| PatagoniaMet: A multi-source hydrometeorological dataset for Western Patagonia | Scientific Data | Aguayo, R.; León-Muñoz, J.; Aguayo, M.; Baez-Villanueva, O.; Zambrano-Bigiarini, M.; Fernández, A.; Jacques-Coper, M. | 2024 | Agua y Extremos; Zonas Costeras | 10.1038/s41597-023-02828-2 | https://doi.org/10.1038/s41597-023-02828-2 | art6 | Vol: 11 Issue: 1 | 20524463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Western Patagonia (40–56°S) is a clear example of how the systematic lack of publicly available data and poor quality control protocols have hindered further hydrometeorological studies. To address these limitations, we present PatagoniaMet (PMET), a compilation of ground-based hydrometeorological data (PMET-obs; 1950–2020), and a daily gridded product of precipitation and temperature (PMET-sim; 1980–2020). PMET-obs was developed considering a 4-step quality control process applied to 523 hydrometeorological time series obtained from eight institutions in Chile and Argentina. Following current guidelines for hydrological datasets, several climatic and geographic attributes were derived for each catchment. PMET-sim was developed using statistical bias correction procedures, spatial regression models and hydrological methods, and was compared against other bias-corrected alternatives using hydrological modelling. PMET-sim was able to achieve Kling-Gupta efficiencies greater than 0.7 in 72% of the catchments, while other alternatives exceeded this threshold in only 50% of the catchments. PatagoniaMet represents an important milestone in the availability of hydro-meteorological data that will facilitate new studies in one of the largest freshwater ecosystems in the world. © 2024, The Author(s). |
| HESS Opinions: The unsustainable use of groundwater conceals a "Day Zero" | Hydrology and Earth System Sciences | Alvarez-Garreton, C.; Boisier, J.; Garreaud, R.; González, J.; Rondanelli, R.; Gayó, E.; Zambrano-Bigiarini, M. | 2024 | Agua y Extremos; Zonas Costeras; Ciudades Resilientes | 10.5194/hess-28-1605-2024 | https://doi.org/10.5194/hess-28-1605-2024 | 1605-1616 | Vol: 28 Issue: 7 | 10275606 | Thomson Reuters ISI (SCIE) | | English | Water scarcity is a pressing global issue driven by increasing water demands and changing climate conditions. Based on novel estimates of water availability and water use in Chile, we examine the challenges and risks associated with groundwater (GW) withdrawals in the country's central-north region (27-35°ĝ€¯S), where extreme water stress conditions prevail. As total water use within a basin approaches the renewable freshwater resources, the dependence on GW reserves intensifies in unsustainable ways. This overuse has consequences that extend beyond mere resource depletion, manifesting into environmental degradation, societal conflict, and economic costs. We argue that the "Day Zero"scenario, often concealed by the uncertain attributes of GW resources, calls for a reconsideration of water allocation rules and a broader recognition of the long-term implications of unsustainable GW use. Our results offer insights for regions worldwide facing similar water scarcity challenges and emphasize the importance of proactive and sustainable water management strategies. © 2024 Camila Alvarez-Garreton et al. |
| Acidithiobacillia class members originating at sites within the Pacific Ring of Fire and other tectonically active locations and description of the novel genus ‘Igneacidithiobacillus’ | Frontiers in Microbiology | Arisan, D.; Moya-Beltrán, A.; Rojas-Villalobos, C.; Issotta, F.; Castro, M.; Ulloa, R.; Chiacchiarini, P.; Díez, B.; Martín, A.; Ñancucheo, I.; Giaveno, A.; Johnson, D.; Quatrini, R. | 2024 | Zonas Costeras | 10.3389/fmicb.2024.1360268 | https://doi.org/10.3389/fmicb.2024.1360268 | art1360268 | Vol: 15 | 1664302X | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Recent studies have expanded the genomic contours of the Acidithiobacillia, highlighting important lacunae in our comprehension of the phylogenetic space occupied by certain lineages of the class. One such lineage is ‘Igneacidithiobacillus’, a novel genus-level taxon, represented by ‘Igneacidithiobacillus copahuensis’ VAN18-1T as its type species, along with two other uncultivated metagenome-assembled genomes (MAGs) originating from geothermally active sites across the Pacific Ring of Fire. In this study, we investigate the genetic and genomic diversity, and the distribution patterns of several uncharacterized Acidithiobacillia class strains and sequence clones, which are ascribed to the same 16S rRNA gene sequence clade. By digging deeper into this data and contributing to novel MAGs emerging from environmental studies in tectonically active locations, the description of this novel genus has been consolidated. Using state-of-the-art genomic taxonomy methods, we added to already recognized taxa, an additional four novel Candidate (Ca.) species, including ‘Ca. Igneacidithiobacillus chanchocoensis’ (mCHCt20-1TS), ‘Igneacidithiobacillus siniensis’ (S30A2T), ‘Ca. Igneacidithiobacillus taupoensis’ (TVZ-G3 TS), and ‘Ca. Igneacidithiobacillus waiarikiensis’ (TVZ-G4 TS). Analysis of published data on the isolation, enrichment, cultivation, and preliminary microbiological characterization of several of these unassigned or misassigned strains, along with the type species of the genus, plus the recoverable environmental data from metagenomic studies, allowed us to identify habitat preferences of these taxa. Commonalities and lineage-specific adaptations of the seven species of the genus were derived from pangenome analysis and comparative genomic metabolic reconstruction. The findings emerging from this study lay the groundwork for further research on the ecology, evolution, and biotechnological potential of the novel genus ‘Igneacidithiobacillus’. Copyright © 2024 Arisan, Moya-Beltrán, Rojas-Villalobos, Issotta, Castro, Ulloa, Chiaccharini, Díez, Martín, Ñancucheo, Giaveno, Johnson and Quatrini. |
| Atmospheric River Brings Warmth and Rainfall to the Northern Antarctic Peninsula During the Mid-Austral Winter of 2023 | Geophysical Research Letters | Bozkurt, D.; Carrasco, J.; Cordero, R.; Fernandoy, F.; Gómez-Contreras, A.; Carrillo, B.; Guan, B. | 2024 | Zonas Costeras | 10.1029/2024GL108391 | https://doi.org/10.1029/2024GL108391 | arte2024GL108391 | Vol: 51 Issue: 13 | 00948276 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Contrasting the extensive research on summer atmospheric rivers (ARs) in the Antarctic Peninsula (AP), winter AR impacts are less understood. This study examines a unique warming event from 1 to 3 July 2023, using in situ winter observations and ERA5 reanalysis. On 2 July, Frei station experienced an extreme warm event with a temperature of 2.7°C and a significant rise in the freezing level, coinciding with winter rainfall. A pressure dipole pattern over the AP, with contrasting circulations over Bellingshausen and Weddell Seas, facilitated an AR, carrying warm, humid air initially from South America/Atlantic and then the southeast Pacific. This shift resulted in anomalous water stable isotope composition in precipitation. Trends suggest a strengthening winter pressure dipole, associated with increased AR frequency and higher temperatures in northern AP. These findings highlight the importance of winter observations in exploring AR impacts, bridging knowledge gaps about winter AR behaviors. © 2024. The Author(s). |
| Atmospheric blocking and temperatures in the Antarctic Peninsula | Science of the Total Environment | Bozkurt, D.; Marín, J.; Verdugo, C.; Barrett, B. | 2024 | Zonas Costeras | 10.1016/j.scitotenv.2024.172852 | https://doi.org/10.1016/j.scitotenv.2024.172852 | art172852 | Vol: 931 | 00489697 | Thomson Reuters ISI (SCIE) | | English | The Antarctic Peninsula (AP) has displayed a propensity for persistent blocking ridges and anticyclonic conditions, particularly during recent summertime extreme weather events. This study investigates atmospheric blocking patterns over the AP through historical (1981–2010) and future (2071–2100, SSP5–8.5) periods using ERA5 reanalysis and six CMIP6 models, including multi-member realizations from two models totaling ten simulations. We focus particularly on 500 hPa geopotential height (Z500) and near-surface air temperature (T2m) anomalies. The historical analysis highlights significant differences between the CMIP6 models and ERA5 reanalysis, especially in the austral winter, with EC-Earth3 and INM-CM4 models matching closest with the ERA5. Future projections show that while the northern AP and the Drake Passage largely do not exhibit a clear trend towards increased blocking, there are exceptions. The EC-Earth3 model predicts more blocking–like conditions northwest of the AP in summer and a pronounced ridge over the Bellingshausen Sea in winter, indicating a potential increase in blocking events. The INM-CM4 model projects a minor increase in summer Z500 heights off the western and southern AP, without clear blocking patterns over the AP, and negligible winter changes. Localized intensification is noted in the northern parts of the blocking domain and southern AP during extreme blocking conditions. These variations are mirrored in T2m anomalies, suggesting warming in the northern and southern sections of AP but little change elsewhere. The results of this study underscore the need to more accurately capture complex blocking mechanisms and their impacts on regional climate patterns around the AP. We also suggest employing refined blocking definitions and incorporating a broader range of climate models to enhance our understanding of blocking patterns and their impacts in a changing climate. © 2024 Elsevier B.V. |
| Characterization of Multi-Decadal Beach Changes in Cartagena Bay (Valparaíso, Chile) from Satellite Imagery | Remote Sensing | Briceño de Urbaneja, I.; Pardo-Pascual, J.; Cabezas-Rabadán, C.; Aguirre, C.; Martínez, C.; Pérez-Martínez, W.; Palomar-Vázquez, J. | 2024 | Zonas Costeras | 10.3390/rs16132360 | https://doi.org/10.3390/rs16132360 | art2360 | Vol: 16 Issue: 13 | 20724292 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Sandy coastlines are very dynamic spaces affected by a variety of natural and human factors. In Central Chile, changes in oceanographic and wave conditions, modes of inter-annual climate variability such as El Niño Southern Oscillation (ENSO), and extreme events such as earthquakes and tsunamis condition the beach morphology. At the same time, direct human actions alter the arrival of sediments to the coast and their alongshore distribution. Despite the relevance of the beaches for this coastal region and the interesting relationship their morphology has with the aforementioned factors, there is a lack of robust morphological datasets to provide a deep characterization and understanding of the dynamism of the Chilean coast. Based on the information provided by satellite-derived shorelines (SDSs) defined by using the SHOREX algorithm, this paper characterizes the morphological changes of Playa Grande in Cartagena Bay (Central Chile) during the period 1985–2019. The shoreline position data are analyzed in the context of changing beach transforming elements, allowing for a better understanding of the changes according to multiple drivers. While some of these factors, such as earthquakes or coastal storms, have a punctual character, changes in wave patterns vary at different time scales, from seasonal to multi-annual, linked to climate phases such as ENSO. Its effects are translated into shoreline erosion and accretion conditioned by the morphology and orientation of the coast while influenced by the availability of sediment in the coastal system. According to that, a conceptual model of the dynamism and redistribution of sediment in the Bay of Cartagena is proposed. The work proves the high utility that the systematic analysis of multi-decadal SDS datasets obtained from the images acquired in the optical by the Landsat and Sentinel-2 offer for beach monitoring and understanding the coastal dynamism. © 2024 by the authors. |
| Women gatherers of nalca (Gunnera tinctoria) as guardians of socioecosystems: Local history, extractivism and restoration in Chile | Extractive Industries and Society | Cameron, J.; Vergara-Pinto, F.; Carrasco Henríquez, N.; Neves, C.; de Cortillas, N.; Flores, C. | 2024 | Zonas Costeras | 10.1016/j.exis.2023.101394 | https://doi.org/10.1016/j.exis.2023.101394 | art101394 | Vol: 17 | 2214790X | Thomson Reuters ISI (SSCI) | | English | In the coastal areas of southern Chile, an interdependence exists between gatherers and the nalca ecosystem known as “pajonal” (swampy spaces), as it provides livelihoods for families and gatherers work to restore and maintain the pajonales. However, the forestry industry has left significant parts of these ecosystems within their margins, impacting their distribution. In this regard, little attention has been paid to the effects of nalca decline on the lives of gatherers and their community responses. Through a historical and ethnographic approach, this paper aims to examine the trajectory followed by women gatherers of the "Agrupación Nalqueros de Pehuén'' in Lebu (Arauco Province, Chile), who have dedicated themselves to the care of socio-ecosystems amidst the globalisation of forest industry and certification process. The results revealed a historical trajectory of nalca gathering marked by interscalar processes that led to governance practices in the interstices of an imposed monocultural geography. In response, the group has resisted and made efforts to achieve the restoration of pajonales amidst forest extractivism. Caring for the nalcas involves territorialising the pajonal and redefining it in accordance with ethical and ecological principles adopted over time for the well-being of their community and the commons they care for. © 2023 Elsevier Ltd |
| Indigenous Knowledge in Post-Pandemic Cultural Tourism: Discussion from Arauco Territories, Chile | Heritage | Carrasco Henríquez, N.; Cid Aguayo, B.; Neves Guzmán, C.; Orellana Ojeda, J. | 2024 | Zonas Costeras | 10.3390/heritage7020040 | https://doi.org/10.3390/heritage7020040 | 829-843 | Vol: 7 Issue: 2 | 25719408 | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | English | In the last two decades, cultural tourism has transformed the aesthetics and the relationship between the actors of the Arauco territories. In the post-COVID context, these transformations could be reinforced, especially considering the actual legal scenario about indigenous rights and the global ecological crisis. In most cases, the indigenous people, with cultural tourism initiatives, highlight their world vision, including the relations with nature. For this reason, we propose to study this scientific problem from the relational ontology perspective. In this study, we describe the situation of cultural tourism in Arauco Province, Chile, where Mapuche people, the Chilean State, and the international market coexist in permanent friction. The main objective is to analyze how the pandemic influenced Mapuche cultural tourism, from the Mapuche cultural perspective and the global conditions for their development. The methods of research mixed historical and ethnographic approaches with a sample of key actors of Mapuche cultural tourism. As results, we can show the Mapuche way of understanding cultural tourism and the new conditions derived from the pandemic and post-pandemic contexts. © 2024 by the authors. |
| Climate and ice sheet dynamics in Patagonia throughout marine isotope stages 2 and 3 | Climate of the Past | Castillo-Llarena, A.; Retamal-Ramírez, F.; Bernales, J.; Jacques-Coper, M.; Prange, M.; Rogozhina, I. | 2024 | Zonas Costeras | 10.5194/cp-20-1559-2024 | https://doi.org/10.5194/cp-20-1559-2024 | 1559-1577 | Vol: 20 Issue: 7 | 18149324 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | During the Last Glacial Maximum (LGM, ∼23 000 to 19 000 years ago), the Patagonian Ice Sheet (PIS) covered the central chain of the Andes between ∼38 to 55° S. Existing paleoclimate evidence-mostly derived from glacial landforms-suggests that maximum ice sheet expansions in the Southern Hemisphere and Northern Hemisphere were not synchronized. However, large uncertainties still exist in the timing of the onset of regional deglaciation and its major drivers. Here we present an ensemble of numerical simulations of the PIS during the LGM. We assess the skill of paleoclimate model products in reproducing the range of atmospheric conditions needed to enable an ice sheet growth in concordance with geomorphological and geochronological evidence. The resulting best-fit climate product is then combined with records from southern South America offshore sediment cores and Antarctic ice cores to drive transient simulations throughout the last 70 ka using a glacial index approach. Our analysis suggests a strong dependence of the PIS geometry on near-surface air temperature forcing. Most ensemble members underestimate the ice cover in the northern part of Patagonia, while tending to expand beyond its constrained eastern boundaries. We largely attribute these discrepancies between the model-based ice geometries and geological evidence to the low resolution of paleoclimate models and their prescribed ice mask. In the southernmost sector, evidence suggests full glacial conditions during marine isotope stage 3 (MIS3, ∼59 400 to 27 800 years ago), followed by a warming trend towards MIS2 (∼27 800 to 14 700 years ago). However, in northern Patagonia, this deglacial trend is absent, indicating a relatively consistent signal throughout MIS3 and MIS2. Notably, Antarctic cores do not reflect a glacial history consistent with the geochronological observations. Therefore, investigations of the glacial history of the PIS should take into account southern midlatitude records to capture effectively its past climatic variability. © Copyright: 2024 Andrés Castillo-Llarena et al. |
| Vertically distinct sources modulate stable isotope signatures and distribution of Mesozooplankton in central Patagonia: The Golfo de Penas - Baker Channel connection and analogies with the Beagle Channel | Journal of Marine Systems | Castro, L.; Soto-Mendoza, S.; Riccialdelli, L.; Presta, M.; Barrientos, P.; González, H.; Daneri, G.; Gutiérrez, M.; Montero, P.; Masotti, I.; Díez, B. | 2024 | Zonas Costeras | 10.1016/j.jmarsys.2023.103892 | https://doi.org/10.1016/j.jmarsys.2023.103892 | art: 103892 | Vol: 241 | 0924-7963 | Thomson Reuters ISI (SCIE) | | English | Using hydrographic and zooplankton sampling along with stable isotope analyses, we determined the influence of freshwater input and of oceanic water ingress at the Golfo de Penas to the Baker Channel (47°S), central Patagonia, on the zooplankton community during mid-spring. Our results show that different taxonomic and functional groups occurred within the mesozooplankton community along an offshore-inshore-oriented transect. Some groups occurred mostly offshore (i.e. euphausiids, fish larvae, stomatopods, amphipods), while others occurred in higher abundance inshore (i.e. medusae, chaetognaths, siphonophores, ostracods). Early life stages of ecologically key species, such as Euphausia vallentini and pelagic stages of Munida gregaria, occurred mostly at the Golfo de Penas. Higher trophic positions estimated from δ15N occurred in mesozooplankton groups inshore (Baker Channel) and lower at the Golfo de Penas, coinciding with the decrease in C:N ratio in zooplankton and with an increase in chlorophyll-a values in the seawater seawards. The δ13C distribution in the zooplankton groups along the offshore-inshore transect showed a positive gradient from the inshore most stations towards the Baker Channel mouth, suggesting a negative relationship with freshwater carrying terrestrial organic carbon and a positive relationship with seawater. However, from the channel mouth seawards, a decrease in δ13C in most zooplankton groups occurred. Within the Baker Channel, low δ13C values occurred in particulate organic matter (POM) at the surface layer, higher values at intermediate depths, and low values at the deepest zones. This uneven distribution of δ13C values in POM and zooplankton, along with the presence of different water masses at different depths suggest an along-basin transport of organic carbon of different sources at different layers: of terrestrial origin at surface, marine origin at mid depth, and from degraded organic matter from offshore entering at higher depths. Thus, a complex scenario of lateral transport of water of different characteristics modulates the presence of zooplankton in different locations and their food sources along the area. These findings resemble others observed in further south in the Beagle Channel (57°S) also in spring but the relative contribution of different carbon sources may differ between Patagonian systems. © 2023 Elsevier B.V. |
| Advancing South American Water and Climate Science through Multidecadal Convection-Permitting Modeling | Bulletin of the American Meteorological Society | Dominguez, F.; Rasmussen, R.; Liu, C.; Ikeda, K.; Prein, A.; Varble, A.; Arias, P.; Bacmeister, J.; Bettolli, M.; Callaghan, P.; Carvalho, L.; Castro, C.; Chen, F.; Chug, D.; Chun, K.; Dai, A.; Danaila, L.; da Rocha, R.; de Lima Nascimento, E.; Dougherty, E.; Dudhia, J.; Eidhammer, T.; Feng, Z.; Fit... | 2024 | Zonas Costeras | 10.1175/BAMS-D-22-0226.1 | https://doi.org/10.1175/BAMS-D-22-0226.1 | E32-E44 | Vol: 105 Issue: 1 | 00030007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | |
| Impact of atmospheric rivers on the winter snowpack in the headwaters of Euphrates-Tigris basin | Climate Dynamics | Ezber, Y.; Bozkurt, D.; Sen, O. | 2024 | Zonas Costeras | 10.1007/s00382-024-07267-2 | https://doi.org/10.1007/s00382-024-07267-2 | | | 09307575 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Understanding the hydrometeorological impacts of atmospheric rivers (ARs) on mountain snowpack is crucial for water resources management in the snow-fed river basins such as the Euphrates-Tigris (ET). In this study, we investigate the contribution of wintertime (December-January–February) ARs to precipitation and snowpack in the headwater regions of the ET Basin for the period of 1979–2019 using a state-of-the-art AR catalog and ERA5 reanalysis data. The results show that AR days in the headwaters region could be warmer by up to 3 °C and wetter by over 5 mm day−1 compared to non-AR days. The contribution of ARs to the total winter precipitation varies from year to year, with a maximum contribution of over 80% in 2010 and an average contribution of 60% over the 40-year period. While snow accumulation on AR days shows spatial variability, the average snow contribution is 27% of the seasonal average, ranging from 12 to 57% for different years. The south-facing parts of the mountain range experience significant snowmelt, with contributions ranging from 15 to 80% for different years. The high total precipitation (60%) and low snowpack (27%) contribution can be attributed to the semi-arid characteristics of the region and the occurrence of rain-on-snow events, where rain falling on existing snow rapidly melts the snowpack. The findings have implications for water resource management and call for continued research to improve our knowledge of ARs and their interactions with the complex terrain of the ET Basin. © The Author(s) 2024. |
| Understanding the impacts of coastal deoxygenation in nitrogen dynamics: an observational analysis | Scientific Reports | Farias, L.; de la Maza, L. | 2024 | Zonas Costeras | 10.1038/s41598-024-62186-w | https://doi.org/10.1038/s41598-024-62186-w | art11826 | Vol: 14 Issue: 1 | 20452322 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Biological production and outgassing of greenhouse gasses (GHG) in Eastern Boundary Upwelling Systems (EBUS) are vital for fishing productivity and climate regulation. This study examines temporal variability of biogeochemical and oceanographic variables, focusing on dissolved oxygen (DO), nitrate, nitrogen deficit (N deficit), nitrous oxide (N2O) and air-sea N2O flux. This analysis is based on monthly observations from 2000 to 2023 in a region of intense seasonal coastal upwelling off central Chile (36°S). Strong correlations are estimated among N2O concentrations and N deficit in the 30–80 m layer, and N2O air-sea fluxes with the proportion of hypoxic water (4 < DO < 89 µmol L−1) in the water column, suggesting that N2O accumulation and its exchange are mainly associated with partial denitrification. Furthermore, we observe interannual variability in concentrations and inventories in the water column of DO, nitrate, N deficit, as well as air-sea N2O fluxes in both downwelling and upwelling seasons. These variabilities are not associated with El Niño-Southern Oscillation (ENSO) indices but are related to interannual differences in upwelling intensity. The time series reveals significant nitrate removal and N2O accumulation in both mid and bottom layers, occurring at rates of 1.5 µmol L−1 and 2.9 nmol L−1 per decade, respectively. Particularly significant is the increase over the past two decades of air-sea N2O fluxes at a rate of 2.9 µmol m−2 d−1 per decade. These observations suggest that changes in the EBUS, such as intensification of upwelling and the prevalence of hypoxic waters may have implications for N2O emissions and fixed nitrogen loss, potentially influencing coastal productivity and climate. © The Author(s) 2024. |
| Atmospheric River Rapids and Their Role in the Extreme Rainfall Event of April 2023 in the Middle East | Geophysical Research Letters | Francis, D.; Fonseca, R.; Bozkurt, D.; Nelli, N.; Guan, B. | 2024 | Zonas Costeras | 10.1029/2024GL109446 | https://doi.org/10.1029/2024GL109446 | arte2024GL109446 | Vol: 51 Issue: 12 | 00948276 | Thomson Reuters ISI (SCIE) | | English | The mesoscale dynamics of a record-breaking Atmospheric River (AR) that impacted the Middle East in mid-April 2023 and caused property damage and loss of life are investigated using model, reanalysis and observational data. The high-resolution (2.5 km) simulations revealed the presence of AR rapids, narrow and long convective structures embedded within the AR that generated heavy precipitation (>4 mm hr−1) as they moved at high speeds (>30 m s−1) from northeastern Africa into western Iran. Gravity waves triggered by the complex terrain in Saudi Arabia further intensified their effects. Given the rising frequency of ARs in this region, AR rapids may be even more impactful in a warming climate, and need to be accounted for in reanalysis and numerical models. © 2024. The Author(s). |
| Atmospheric Rivers in South-Central Chile: Zonal and Tilted Events | Atmosphere | Garreaud, R.; Jacques-Coper, M.; Marín, J.; Narváez, D. | 2024 | Zonas Costeras; Agua y Extremos | 10.3390/atmos15040406 | https://doi.org/10.3390/atmos15040406 | art406 | Vol: 15 Issue: 4 | 20734433 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The extratropical west coast of South America has one of the largest frequencies of landfalling atmospheric rivers (ARs), with dozens of events per season that account for ~50% of the annual precipitation and can produce extreme rainfall events in south-central Chile. Most ARs form an acute angle with the Andes, but, in some cases, the moist stream impinges nearly perpendicular to the mountains, referred to as zonal atmospheric rivers (ZARs). Enhanced surface-based and upper-air measurements in Concepcion (36.8° S), as well as numerical simulations, were used to characterize a ZAR and a meridionally oriented AR in July 2022. They represent extremes of the broad distribution of winter storms in this region and exhibit key features that were found in a composite analysis based on larger samples of ZARs and tilted ARs. The latter is associated with an upper-level trough, broad-scale ascent, extratropical cyclone, and cold front reaching southern Chile. Instead, ZARs are associated with tropospheric-deep, strong zonal flow and a stationary front across the South Pacific, with ascent restricted upstream of the Andes. Consequently, ZARs have minimum precipitation offshore but a marked orographic precipitation enhancement and exhibit relatively warm temperatures, thus resulting in an augmented risk of hydrometeorological extreme events. © 2024 by the authors. |
| Screening CMIP6 models for Chile based on past performance and code genealogy | Climatic Change | Gateño, F.; Mendoza, P.; Vásquez, N.; Lagos-Zúñiga, M.; Jiménez, H.; Jerez, C.; Vargas, X.; Rubio-Álvarez, E.; Montserrat, S. | 2024 | Zonas Costeras | 10.1007/s10584-024-03742-1 | https://doi.org/10.1007/s10584-024-03742-1 | art87 | Vol: 177 Issue: 6 | 01650009 | Thomson Reuters ISI (SCIE) | | English | We describe and demonstrate a two-step approach for screening global climate models (GCMs) and produce robust annual and seasonal climate projections for Chile. First, we assess climate model simulations through a Past Performance Index (PPI) inspired by the Kling-Gupta Efficiency, which accounts for climatological averages, interannual variability, seasonal cycles, monthly probabilistic distribution, spatial patterns of climatological means, and the capability of the GCMs to reproduce teleconnection responses to El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). The PPI formulation is flexible enough to include additional variables and evaluation metrics and weight them differently. Secondly, we use a recently proposed GCM classification based on model code genealogy to obtain a subset of independent model structures from the top 60% GCMs in terms of PPI values. We use this approach to evaluate 27 models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and generate projections in five regions with very different climates across continental Chile. The results show that the GCM evaluation framework is able to identify pools of poor-performing and well-behaved models at each macrozone. Because of its flexibility, the model features that may be improved through bias correction can be excluded from the model evaluation process to avoid culling GCMs that can replicate other climate features and observed teleconnections. More generally, the results presented here can be used as a reference for regional studies and GCM selection for dynamical downscaling, while highlighting the difficulty in constraining precipitation and temperature projections. © The Author(s), under exclusive licence to Springer Nature B.V. 2024. |
| Trends in seasonal precipitation extremes and associated temperatures along continental Chile | Climate Dynamics | Lagos-Zúñiga, M.; Mendoza, P.; Campos, D.; Rondanelli, R. | 2024 | Zonas Costeras | 10.1007/s00382-024-07127-z | https://link.springer.com/10.1007/s00382-024-07127-z | 4205-4222 | Vol: 62 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | We characterize trends in maximum seasonal daily precipitation (seasonal Rx1day), minimum (Tn), and maximum (Tx) daily temperatures during days with precipitation over continental Chile for the period 1979–2017, using surface stations and the AgERA5 gridded product derived from the ERA5 reanalysis dataset. We also examine seasonal trends of Sea Surface Temperature (SST), Precipitable Water (PW), Convective Available Potential Energy (CAPE), Eddy Kinetic Energy (EKE), Atmospheric Rivers (ARs) frequency, and upper air observations to seek possible mechanisms that explain precipitation trends. Our results show an increase in seasonal Rx1day during fall in the south part of Northern Chile (15–30°S) and during fall and winter in Austral Chile (45–57°S), and mostly negative trends in Central Chile (30–36°S), where a few locations with positive trends along the coast during summer. Temperature trends presented cooling patterns north of 33°S in almost all the seasons (< -2 °C/dec), while warming trends prevail south of 38°S (> 1 °C/dec). The highest values in Tn trends are obtained on the western slopes of the Andes around 30°S. We also explore temperature scaling in surface stations, finding strong positive super Clausius Clapeyron with Tn, especially between fall and spring in the 33–40°S region. Sounding observations in five stations across Chile suggest warming trends at 23.5°, 33°S, and 53°S, with a stabilization effect by enhanced warming in the upper troposphere, while presenting cooling trends in Puerto Montt (41.5°S). Seasonal trends in PW reveal moistening along southern Peru and northern Chile during spring and summer. Positive trends in CAPE are observed over 35–40°S (austral summer and fall) and the north Altiplano (autumn). SST analyses reveal strong cooling around 30°S in winter, which may explain the negative trends in seasonal Rx1day in central Chile. A warming spot on the northern Peruvian coast during fall may be responsible for humidification in front of Northern Chile, particularly during summer and fall. Positive EKE trends are detected south of 40°S, being stronger and reaching almost all of the coast during spring. ARs frequency unveils negative trends up to -5 days/dec during summer and positive trends of 1 day/dec in 40°- 50°S coastal regions during spring. More generally, the results presented here shed light on the main large-scale processes driving recent trends in precipitation extremes across continental Chile. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024. |
| Unraveling the Dynamics of Moisture Transport During Atmospheric Rivers Producing Rainfall in the Southern Andes | Geophysical Research Letters | Mudiar, D.; Rondanelli, R.; Valenzuela, R.; Garreaud, R. | 2024 | Zonas Costeras; Agua y Extremos | 10.1029/2024GL108664 | https://doi.org/10.1029/2024GL108664 | arte2024GL108664 | Vol: 51 Issue: 13 | 00948276 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Atmospheric rivers (ARs) are known to produce both beneficial and extreme rainfall, leading to natural hazards in Chile. Motivated to understand moisture transport during AR events, this study performs a moisture budget analysis along 50 zonally elongated ARs reaching the western coast of South America. We identify the convergence of moist air masses of tropical/subtropical origin along the AR as the primary source of vertically integrated water vapor (IWV). Over the open ocean, moisture convergence is nearly balanced by precipitation. The advection of moisture along the AR, although smaller compared to mass convergence, significantly increases toward the landfalling region. The near conservation of IWV over the open ocean, observed by tracking a Lagrangian atmospheric column along the ARs, is the explanation behind the seemingly tropical origin of ARs in time-lapse visualizations of IWV. © 2024. The Author(s). |
| Exploring the multifunctional landscapes model in areas dominated by non-native tree plantations | Trees, Forests and People | Ortiz, A.; Gayó, E.; Henríquez, N.; Henríquez, B.; Pauchard, A. | 2024 | Zonas Costeras; Ciudades Resilientes | 10.1016/j.tfp.2024.100617 | https://doi.org/10.1016/j.tfp.2024.100617 | art100617 | Vol: 17 | 26667193 | Thomson Reuters ISI (ESCI) | All Open Access; Hybrid Gold Open Access | English | Multifunctional landscapes offer an integrated approach to production, conservation, and human well-being. However, the challenges of implementing them in territories where plantations dominate are yet not well understood. This is the case in Chile, where plantations of non-native pines and eucalypts are extensively planted in its South-Central regions for timber and pulp. The resulting landscape homogenization, environmental degradation, and increased wildfire risk have caused and exacerbated conflicts, impacting biodiversity and the well-being of local communities and the Indigenous Mapuche Peoples. After the mega-wildfires in the region in 2023, science-policy discourse promoted the multifunctional landscapes model as a way to increase resilience. But what does this multifunctionality mean in challenging social-ecological contexts? Here, we aim to explore and deconstruct the multifunctional landscapes model in the context of the complex social-ecological systems of South-Central Chile. In this study, a review of the literature and semi-structured interviews with regional experts were used to better understand the challenges and opportunities presented by multifunctional landscapes. The results show a need to deepen the knowledge of how to move the model into practice, such as how to identify and decide compatible activities in the landscape. The thematic analysis of the interviews showed that restoration and water security are shared goals across the diverse actors in South-Central Chile. However, there were significant differences in knowledge, experiences and resources. While a number of landscape initiatives exist in the region, significant work is needed to build a common vision before the potential of multifunctional landscapes can be realized. © 2024 The Author(s) |
| Toward a South American High-Impact Weather Reports Database | Bulletin of the American Meteorological Society | Salio, P.; Bechis, H.; Ribeiro, B.; de Lima Nascimento, E.; Galligani, V.; Garcia, F.; Alvarenga, L.; de los Milagros Alvarezs Imaz, M.; Baissac, D.; Barle, M.; Bastías-Curivil, C.; Benedicto, M.; Cancelada, M.; da Costa, I.; D’Amen, D.; de Elia, R.; Diaz, D.; Páez, A.; González, S.; Goede, V.; Goñi... | 2024 | Zonas Costeras; Agua y Extremos | 10.1175/BAMS-D-23-0063.1 | https://doi.org/10.1175/BAMS-D-23-0063.1 | E1204-E1217 | Vol: 105 Issue: 7 | 00030007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Despite southern South America being recognized as a hotspot for deep convective storms, little is known about the socioenvironmental impacts of high-impact weather (HIW) events. Although there have been past efforts to collect severe weather reports in the region, they have been highly fragmented among and within countries, sharing no common protocol, and limited to a particular phenomenon, a very specific region, or a short period of time. There is a pressing need for a more comprehensive understanding of the present risks linked to HIW events, specifically deep convective storms, on a global scale as well as their variability and potential future evolution in the context of climate change. A database of high-quality and systematic HIW reports and associated socioenvironmental impacts is essential to understand the regional atmospheric conditions leading to hazardous weather, to quantify its predictability, and to build robust early warning systems. To tackle this problem and following successful initiatives in other regions of the world, researchers, national weather service members, and weather enthusiasts from Argentina, Brazil, Chile, Paraguay, and Uruguay have embarked on a multinational collaboration to generate a standardized database of reports of HIW events principally associated with convective storms and their socioenvironmental impacts in South America. The goal of this paper is to describe this unprecedented initiative over the region, to summarize first results, and to discuss the potential applications of this collaboration. SIGNIFICANCE STATEMENT: The South American Meteorological Hazards and their Impacts Database represents a collaborative multinational initiative aimed at systematically gathering data on high-impact weather events. Cross-border information exchange and collaborative efforts between national weather services, the academic sector, users, and weather enthusiasts will improve multihazard-impact-based forecasts and risk management strategies in the region. © 2024 American Meteorological Society. |
| Diversity and functionality of soil prokaryotic communities in antarctic volcanic soils: insights from penguin-influenced environments | Polar Biology | Segura, D.; Jordaan, K.; Díez, B.; Tamayo-Leiva, J.; Doetterl, S.; Wasner, D.; Cifuentes-Anticevic, J.; Casanova-Katny, A. | 2024 | Zonas Costeras | 10.1007/s00300-024-03273-6 | https://doi.org/10.1007/s00300-024-03273-6 | | | 07224060 | Thomson Reuters ISI (SCIE) | | English | In the nutrient-limited Antarctic terrestrial habitat, penguins transfer a significant amount of nutrients from the marine to the terrestrial ecosystem through their depositions (i.e., guano). This guano influences soil physicochemical properties, leading to the formation of ornithogenic soil rich in nutrients and organic matter. We hypothesize that soil prokaryotic communities will be strongly influenced by the contribution of nitrogenous nutrients from penguin rookeries, maintaining the influence over long distances. The objective was to establish how the soil prokaryotic diversity and community structure change with distance from a penguin colony, which provides large amounts of guano and nitrogenous compounds, and to study the effects of these nutrients on the functional role of these communities. Methods include volcanic soil sampling along a 1200 m transect from the penguin active rookery and the characterization of soil nutrient content and soil prokaryotic communities using 16S rRNA high-throughput amplicon sequencing. In contrast to our hypothesis, the results showed that the impact of guano from the penguin colony was restricted to the first 300 m. Probably because the penguin rookery was sheltered, strong wind and wind direction did not affect the transport of nutrients from the penguin rookery. Areas close to the penguin rookery were dominated by Proteobacteria and Bacteroidetes, while areas situated further away were dominated by Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Nitrospirae, and Planctomycetes. Beta diversity analysis among the soil prokaryotic communities revealed a high degree of community heterogeneity, strongly associated with N compound characteristics (NH4, NO3, and %N), C, and pH. Inferences from N metabolism genes suggest a high potential of the microbial community for dissimilatory nitrate reduction genes (DNRA) to ammonium, assimilatory nitrate reduction (ANR), and denitrification. Although it is assumed that the nitrogenous compounds of the penguin colonies reach long distances and affect the prokaryotic community, this effect can vary with wind directions or the morphology of the site, reducing the impact of the guano over long distances, as our results indicate. On the other hand, functional predictions give some clues about the main actors in nitrogen cycling, through processes like dissimilatory nitrate reduction, assimilatory nitrate reduction, and denitrification. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024. |
| Picoplanktonic methane production in eutrophic surface waters | Biogeosciences | Tenorio, S.; Farías, L. | 2024 | Zonas Costeras | 10.5194/bg-21-2029-2024 | https://doi.org/10.5194/bg-21-2029-2024 | 2029-2050 | Vol: 21 Issue: 8 | 17264170 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Over the past decade, extensive research has delved into the methane (CH4) paradox, which involves aerobic CH4 production. We present noteworthy observations of CH4 oversaturation within the surface layer of the central Chile upwelling zone (36°S, 73°W) over two consecutive seasonal cycles (2018-2021). Complementing these observations, CH4 cycling experiments were conducted, utilizing distinct plankton fractions (encompassing the natural planktonic community, fractions <150, <3 and <0.2μm), in different productivity periods of phytoplanktonic production and composition throughout the year. Our findings underscore the pivotal role of picoplankton (<3μm) in CH4 production on the ocean surface, contrasting with the limited contribution of larger microorganisms (<150μm). Notably, incubations with methylated substrates, such as methylphosphonic acid (MPn) and trimethylamine (TMA), induce heightened CH4 production within the picoplanktonic fraction. This phenomenon is consistently observed during both upwelling (austral spring-summer) and non-upwelling (winter) seasons, with significance in the latter period, when Synechococcus sp. exhibits notably high relative abundance. Long-term microcosm experiments highlight the crucial roles played by heterotrophic bacteria and cyanobacteria in methylotrophic methanogenesis. This process enhances CH4 production, facilitated by the recycling of dissolved organic carbon (DOC). Picoplankton emerges as a pivotal factor influencing the recycling of methylated substrates, and it is responsible for maintaining CH4 supersaturation. These findings provide valuable insights into the biogeochemical processes driving CH4 dynamics, particularly in highly productive upwelling areas. © Copyright: |
| New insights on the interannual surface mass balance variability on the South Shetland Islands glaciers, northerly Antarctic Peninsula | Global and Planetary Change | Torres, C.; Bozkurt, D.; Carrasco-Escaff, T.; Bolibar, J.; Arigony-Neto, J. | 2024 | Zonas Costeras; Agua y Extremos | 10.1016/j.gloplacha.2024.104506 | https://doi.org/10.1016/j.gloplacha.2024.104506 | art104506 | Vol: 239 | 09218181 | Thomson Reuters ISI (SCIE) | | English | Few studies have assessed a comprehensive understanding of how the seasonal and interannual variability and trends of the surface mass balance (SMB), including the influence of atmospheric river (ARs), are governed by the climate on the South Shetland Islands (SSI) glaciers located in the northerly Antarctic Peninsula (AP). To address this gap, we comprehensively analyzed the correlations and regressions between seasonal and annual SMB with regional to global climate indices and a state-of-the-art AR tracking database from 1980 to 2019. The daily and monthly SMB was obtained from two physical glaciological models, which was verified against 19 years of annual and seasonal glacier-wide SMB observations available in three glaciers (Johnsons, Hurd, and Bellingshausen), showing a good ability to capture interannual and seasonal variability. Results indicate a low dependence of the SMB on main atmospheric modes of variability (e.g., El Niño-Southern Oscillation and the Southern Annular Mode), and a moderate dependence on regional climate indices based on atmospheric pressure anomalies and sea surface temperature anomalies over the Drake Passage. Furthermore, our findings reveal that ARs have different effects on the SMB depending on the season. For example, winter ARs tend to boost accumulation due to increased snowfall, while summer ARs tend to intensify surface melting due to increased sensible heat flux. Our study highlights the Drake Passage as a key region that has the potential to influence the interannual and seasonal variability of the SMB and other climate variables, such as air temperature and snowfall over the SSI. We suggest that future work should consider this region to better understand the past, present and future climate changes on the SSI and surrounding areas. © 2024 |
| Role of atmospheric rivers in shaping long term Arctic moisture variability | Nature Communications | Wang, Z.; Ding, Q.; Wu, R.; Ballinger, T.; Guan, B.; Bozkurt, D.; Nash, D.; Baxter, I.; Topál, D.; Li, Z.; Huang, G.; Chen, W.; Chen, S.; Cao, X.; Chen, Z. | 2024 | Zonas Costeras | 10.1038/s41467-024-49857-y | https://doi.org/10.1038/s41467-024-49857-y | art5505 | Vol: 15 Issue: 1 | 20411723 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Atmospheric rivers (ARs) reaching high-latitudes in summer contribute to the majority of climatological poleward water vapor transport into the Arctic. This transport has exhibited long term changes over the past decades, which cannot be entirely explained by anthropogenic forcing according to ensemble model responses. Here, through observational analyses and model experiments in which winds are adjusted to match observations, we demonstrate that low-frequency, large-scale circulation changes in the Arctic play a decisive role in regulating AR activity and thus inducing the recent upsurge of this activity in the region. It is estimated that the trend in summertime AR activity may contribute to 36% of the increasing trend of atmospheric summer moisture over the entire Arctic since 1979 and account for over half of the humidity trends in certain areas experiencing significant recent warming, such as western Greenland, northern Europe, and eastern Siberia. This indicates that AR activity, mostly driven by strong synoptic weather systems often regarded as stochastic, may serve as a vital mechanism in regulating long term moisture variability in the Arctic. © The Author(s) 2024. |
| The Extraordinary March 2022 East Antarctica “Heat” Wave. Part I: Observations and Meteorological Drivers | Journal of Climate | Wille, J.; Alexander, S.; Amory, C.; Baiman, R.; Barthélemy, L.; Bergstrom, D.; Berne, A.; Binder, H.; Blanchet, J.; Bozkurt, D.; Bracegirdle, T.; Casado, M.; Choi, T.; Clem, K.; Codron, F.; Datta, R.; Di Battista, S.; Favier, V.; Francis, D.; Fraser, A.; Fourré, E.; Garreaud, R.; Genthon, C.; Gorod... | 2024 | Zonas Costeras; Agua y Extremos | 10.1175/JCLI-D-23-0175.1 | https://doi.org/10.1175/JCLI-D-23-0175.1 | 757-778 | Vol: 37 Issue: 3 | 08948755 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30°–40°C temperature anomalies across the ice sheet. This record-shattering event saw numerous monthly temperature records being broken including a new all-time temperature record of -9.4°C on 18 March at Concordia Station despite March typically being a transition month to the Antarctic coreless winter. The driver for these temperature extremes was an intense atmospheric river advecting subtropical/midlatitude heat and moisture deep into the Antarctic interior. The scope of the temperature records spurred a large, diverse collaborative effort to study the heat wave’s meteorological drivers, impacts, and historical climate context. Here we focus on describing those temperature records along with the intricate meteorological drivers that led to the most intense atmospheric river observed over East Antarctica. These efforts describe the Rossby wave activity forced from intense tropical convection over the Indian Ocean. This led to an atmospheric river and warm conveyor belt intensification near the coastline, which reinforced atmospheric blocking deep into East Antarctica. The resulting moisture flux and upper-level warm-air advection eroded the typical surface temperature inversions over the ice sheet. At the peak of the heat wave, an area of 3.3 million km2 in East Antarctica exceeded previous March monthly temperature records. Despite a temperature anomaly return time of about 100 years, a closer recurrence of such an event is possible under future climate projections. In Part II we describe the various impacts this extreme event had on the East Antarctic cryosphere. © 2024 American Meteorological Society. |
| The Extraordinary March 2022 East Antarctica “Heat” Wave. Part II: Impacts on the Antarctic Ice Sheet | Journal of Climate | Wille, J.; Alexander, S.; Amory, C.; Baiman, R.; Barthélemy, L.; Bergstrom, D.; Berne, A.; Binder, H.; Blanchet, J.; Bozkurt, D.; Bracegirdle, T.; Casado, M.; Choi, T.; Clem, K.; Codron, F.; Datta, R.; Di Battista, S.; Favier, V.; Francis, D.; Fraser, A.; Fourré, E.; Garreaud, R.; Genthon, C.; Gorod... | 2024 | Zonas Costeras; Agua y Extremos | 10.1175/JCLI-D-23-0176.1 | https://doi.org/10.1175/JCLI-D-23-0176.1 | 779-799 | Vol: 37 Issue: 3 | 08948755 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 308–408C temperature anomalies across the ice sheet. In Part I, we assessed the meteorological drivers that generated an intense atmospheric river (AR) that caused these record-shattering temperature anomalies. Here, we continue our large collaborative study by analyzing the widespread and diverse impacts driven by the AR landfall. These impacts included widespread rain and surface melt that was recorded along coastal areas, but this was outweighed by widespread high snowfall accumulations resulting in a largely positive surface mass balance contribution to the East Antarctic region. An analysis of the surface energy budget indicated that widespread downward longwave radiation anomalies caused by large cloud-liquid water contents along with some scattered solar radiation produced intense surface warming. Isotope measurements of the moisture were highly elevated, likely imprinting a strong signal for past climate reconstructions. The AR event attenuated cosmic ray measurements at Concordia, something previously never observed. Last, an extratropical cyclone west of the AR landfall likely triggered the final collapse of the critically unstable Conger Ice Shelf while further reducing an already record low sea ice extent. © 2024 American Meteorological Society. |
| Climate projections of oceanographic variables in the Exclusive Economic Zone of Ecuador: A 21st century perspective to inform impact and adaptation assessment | Regional Studies in Marine Science | Winckler, P.; Farías, L.; Vicuña, S.; Esparza, C.; Mora, J.; Chubretovic, R.; Cabrera, F.; Zambrano-Sánchez, N.; Caza, P.; González, R. | 2024 | Zonas Costeras | 10.1016/j.rsma.2024.103612 | https://doi.org/10.1016/j.rsma.2024.103612 | art103612 | Vol: 77 | 23524855 | Thomson Reuters ISI (SCIE) | | English | Climate projections of ocean variables are essential to inform adaptation strategies and plans involving open and coastal oceanic regions. Assessment of baseline and projections of sea surface temperature (SST), pH, dissolved oxygen (DO), mean sea level (MSL), waves coastal flooding within Ecuador's Exclusive Economic Zone, including Galapagos Islands are reported herein. With different magnitudes of change, both near-future (2021–2050) and far-future projections (2051–2080) show a statistically robust increase in SST, MSL rise and a reduction in pH, a proxy for acidification. In contrast, DO decrease is only observed in surface (0–100 m) but not in subsurface waters (100–400 m). The likelihood of extreme sea level events in the coastal cities of La Libertad, Manta and Esmeraldas would remain almost unchanged for near-future projections (2026–2045) whereas, for end-of-century projections (2081–2100), historical 1 in a 100-year extreme flooding events would become yearly occurrences. The generated data product offers a state-of-the-art research and management tool for the 21st century under the combined stressors of global climate change. Since the eastern Tropical Pacific Ocean is one of the most productive and biodiverse worldwide due to the equatorial upwelling system, possible impacts on marine biodiversity, social, and economic systems are discussed. © 2024 Elsevier B.V. |
| Variability in oceanographic conditions affecting Mesophotic Ecosystems along the South Eastern Pacific: Latitudinal trends and potential for climate refugia | Journal of Marine Systems | de la Maza, L.; Wieters, E.; Beldade, R.; Landaeta, M.; Perez-Matus, A.; Navarrete, S. | 2024 | Zonas Costeras | 10.1016/j.jmarsys.2024.103999 | https://doi.org/10.1016/j.jmarsys.2024.103999 | art103999 | Vol: 245 | 09247963 | Thomson Reuters ISI (SCIE) | | English | Oceans have been changing at the fastest pace since the beginning of the Holocene. The South Eastern Pacific (SEP), including the Humboldt Upwelling Ecosystem (HUE) is subject to changes in upwelling winds, temperature, El Niño, and the ever-increasing local anthropogenic stressors, all of which have been documented for surface coastal waters where in-situ and remote observations are readily available. Temporal and spatial changes in the adjacent deeper waters where diverse Mesophotic Ecosystems are found have been scarcely documented. These marine ecosystems have been the focus of ecological studies for less than two decades. Here we provide an overview of the thermal variability at mesophotic depths and assess their potential as climatic refugia along all SEP ecoregions. We analyzed a time series of temperature and salinity from a 19 yr reanalysis based on remote and in-situ observations (CTD, ARGO, XBTs, moorings) to quantify variability in the Tropical (0–5°S), Northern Warm Temperate (5–30°S); Southern Warm Temperate (30–39.5°S) and Magellanic subregions (39.5–45°S), at two mesophotic depth strata (50 and 100 m), and a reference surface (5 m) depth. We assessed variability in the seasonal, interannual (El Niño) and ‘long-term’ (ca. 20 yr) scales, and the relationship with wind velocities. The thermal depth gradient between surface and mesophotic depths did not change smoothly with latitude but peaked within the northern portion of the warm temperate subregion, decreasing towards lower and higher latitudes. Seasonal variation in temperature was also largest in the north and south temperate subregions and minimal in the Magellanic subregion. Depth dampening of seasonal temperature variation was also strengthened at intermediate latitudes and much reduced in the tropics, where seasonal variation at mesophotic depths was similar to that at the surface. The strong interannual El Niño events were identified at all depths in tropical and temperate subregions, with stronger standardized effects at mesophotic layers than at the surface. Long-term (ca. two decades) temperature trends were significant and changed direction from warming to cooling along the SEP but were generally patchier at mesophotic layers. Spatial temperature gradients have remained relatively stable over the past two decades and were stronger at the surface than at mesophotic depths, and stronger within the tropics than in all other subregions. Surprisingly, the velocity of climate change was patchier and generally faster at mesophotic layers than at the surface. We conclude that, judging solely by physical environmental conditions, mesophotic ecosystems may be used by species with very different temperature affinities in temperate subregions, while in the tropics, more overlap in temperature affinities of component species may be found. Importantly, while the seasonal amplitude is reduced at mesophotic depth in most subregions, except the tropics, interannual disturbances affect mesophotic depths at least as strongly as they do surface waters and climate change velocities are faster at mesophotic depths than at surface. Thus, these ecosystems are not sheltered from inter-annual and longer-term forcing and their biotas might be more vulnerable to climate change than shallow coastal ecosystems. © 2024 Elsevier B.V. |
| Snow Cover Reconstruction in the Brunswick Peninsula, Patagonia, Derived from a Combination of the Spectral Fusion, Mixture Analysis, and Temporal Interpolation of MODIS Data | Remote Sensing | Aguirre, F.; Bozkurt, D.; Sauter, T.; Carrasco, J.; Schneider, C.; Jaña, R.; Casassa, G. | 2023 | Zonas Costeras | 10.3390/rs15225430 | https://doi.org/10.3390/rs15225430 | art5430 | Vol: 15 Issue: 22 | 20724292 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Several methods based on satellite data products are available to estimate snow cover properties, each one with its pros and cons. This work proposes and implements a novel methodology that integrates three main processes applied to MODIS satellite data for snow cover property reconstruction: (1) the increase in the spatial resolution of MODIS (MOD09) data to 250 m using a spectral fusion technique; (2) a new proposal of snow-cloud discrimination; (3) the daily spatio-temporal reconstruction of snow extent and its albedo signature using the endmembers extraction and spectral mixture analyses. The snow cover reconstruction method was applied to the Brunswick Peninsula, Chilean Patagonia, a low-elevation (<1500 m a.s.l.) mid-latitude area. The results show a 98% agreement between MODIS snow detection and ground-based snow measurements at the automatic weather station, Tres Morros (53.3174°S, 71.2790°W), with fractional snow cover values between 20% and 50%, showing a close relationship between snow and vegetation type. The number of snow days compiled from the MODIS data indicates a good performance (Pearson’s correlation of 0.9) compared with the number of skiing days at the Cerro Mirador ski center, Punta Arenas. Although the number of seasonal snow days showed a significant increasing trend of 0.54 days/year in the Brunswick Peninsula during the 2000–2020 period, a significant decrease of −4.64 days/year was detected in 2010–2020. © 2023 by the authors. |
| Effects of hydrogeochemistry on the microbial ecology of terrestrial hot springs | Microbiology Spectrum | Barbosa, C.; Tamayo-Leiva, J.; Alcorta, J.; Salgado, O.; Daniele, L.; Morata, D.; Díez, B. | 2023 | Zonas Costeras | 10.1128/SPECTRUM.00249-23 | https://doi.org/10.1128/SPECTRUM.00249-23 | 1-23 | Vol: 11 Issue: 5 | 21650497 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Temperature, pH, and hydrochemistry of terrestrial hot springs play a critical role in shaping thermal microbial communities. However, the interactions of biotic and abiotic factors at this terrestrial-aquatic interface are still not well understood on a global scale, and the question of how underground events influence microbial communities remains open. To answer this, 11 new samples obtained from the El Tatio geothermal field were analyzed by 16S rRNA amplicon sequencing (V4 region), along with 191 samples from previous publications obtained from the Taupo Volcanic Zone, the Yellowstone Plateau Volcanic Field, and the Eastern Tibetan Plateau, with their temperature, pH, and major ion concentration. Microbial alpha diversity was lower in acid-sulfate waters, and no significant correlations were found with temperature. However, moderate correlations were observed between chemical parameters such as pH (mostly constrained to temperatures below 70°C), SO42− and abundances of members of the phyla Armatimonadota, Deinococcota, Chloroflexota, Campilobacterota, and Thermoplasmatota. pH and SO42− gradients were explained by phase separation of sulfur-rich hydrothermal fluids and oxidation of reduced sulfur in the steam phase, which were identified as key processes shaping these communities. Ordination and permutational analysis of variance showed that temperature, pH, and major element hydrochemistry explain only 24% of the microbial community structure. Therefore, most of the variance remained unexplained, suggesting that other environmental or biotic factors are also involved and highlighting the environmental complexity of the ecosystem and its great potential to test niche theory ecological associated questions. Copyright © 2023 Barbosa et al. |
| Engineering the catalytic activity of an Antarctic PET-degrading enzyme by loop exchange | Protein Science | Blázquez-Sánchez, P.; Vargas, J.; Furtado, A.; Griñen, A.; Leonardo, D.; Sculaccio, S.; Pereira, H.; Sonnendecker, C.; Zimmermann, W.; Díez, B.; Garratt, R.; Ramírez-Sarmiento, C. | 2023 | Zonas Costeras | 10.1002/pro.4757 | https://doi.org/10.1002/pro.4757 | arte4757 | Vol: 32 Issue: 9 | 09618368 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Several hydrolases have been described to degrade polyethylene terephthalate (PET) at moderate temperatures ranging from 25°C to 40°C. These mesophilic PET hydrolases (PETases) are less efficient in degrading this plastic polymer than their thermophilic homologs and have, therefore, been the subject of many protein engineering campaigns. However, enhancing their enzymatic activity through rational design or directed evolution poses a formidable challenge due to the need for exploring a large number of mutations. Additionally, evaluating the improvements in both activity and stability requires screening numerous variants, either individually or using high-throughput screening methods. Here, we utilize instead the design of chimeras as a protein engineering strategy to increase the activity and stability of Mors1, an Antarctic PETase active at 25°C. First, we obtained the crystal structure of Mors1 at 1.6 Å resolution, which we used as a scaffold for structure- and sequence-based chimeric design. Then, we designed a Mors1 chimera via loop exchange of a highly divergent active site loop from the thermophilic leaf-branch compost cutinase (LCC) into the equivalent region in Mors1. After restitution of an active site disulfide bond into this chimera, the enzyme exhibited a shift in optimal temperature for activity to 45°C and an increase in fivefold in PET hydrolysis when compared with wild-type Mors1 at 25°C. Our results serve as a proof of concept of the utility of chimeric design to further improve the activity and stability of PETases active at moderate temperatures. © 2023 The Protein Society. |
| ENSO-Related Precipitation Variability in Central Chile: The Role of Large Scale Moisture Transport | Journal of Geophysical Research: Atmospheres | Campos, D.; Rondanelli, R. | 2023 | Zonas Costeras | 10.1029/2023JD038671 | https://doi.org/10.1029/2023JD038671 | arte2023JD038671 | Vol: 128 Issue: 17 | 2169897X | Thomson Reuters ISI (SCIE) | All Open Access; Green Open Access | English | Interannual variability of precipitation in Central Chile has long been associated with changes in the dry atmospheric dynamics of the Southern Pacific. This is due to the interaction between the extratropical storm track and the polar anticyclonic circulations established by the Pacific South American (PSA) teleconnection mode, which results from changes in tropical convection. Here, we show that an enhanced subtropical moisture transport during the warm ENSO phase leads to an increase in the frequency of atmospheric rivers, larger values of precipitable water, and heightened zonal integrated water vapor transport. This occurs in a region of the Southern Pacific situated between the tropical high and the subtropical low of the PSA mode. These increases in zonal water vapor transport result in greater precipitation and moister, long-lived atmospheric rivers making landfall in Central Chile. © 2023. American Geophysical Union. All Rights Reserved. |
| Coastal territorialities and ontologies in friction: a review of multiple coastal settlements in the context of climate change | Journal of Coastal Conservation | Carrasco Henríquez, N.; Vergara-Pinto, F. | 2023 | Zonas Costeras | 10.1007/s11852-023-00947-x | https://doi.org/10.1007/s11852-023-00947-x | art: 17 | Vol: 27 Issue: 3 | 1400-0350 | Thomson Reuters ISI (SCIE) | | English | Co-existence among multiple coastal settlements (MCS) following diverse ecological, economic, and cultural traditions drives to examine the territorial and ontological dimensions underlying the development of heterogeneous worldviews within common coastal geographies. In the case of the coastal zone in Chile, cultural diversity is evident as a historical field of dispute, which in the current context of adaptation to climate change may be reproducing or moving to other new trajectories. Using a literature review specifically on the case of the Arauco province in Chile, this article aims to identify a typology of multiple territorialities and ontologies interacting and being sustained by common coastal environments, although embedded in frictions and both structural and historical inequalities. Through thematic analysis framed in poststructuralist political ecology, this review identified three categories of territorialities that develop in the study area (i.e. colonial, intercultural, and interstitial). Each one leads to recognising the power dynamics that underlie the interactions of practices and discourses on the territory, the sea, and the conservation of nature. Results show that the historical predominance of modern ontology has produced permissible ways of being and moving through this geography. In contrast, resistance has been generated by other ways of living based on relational, traditional, and contemporaneous ontologies with discourses aimed at socio-ecological equilibrium. The current challenge is understanding these ontological frictions and interstices wherein multiple territorialities configured in a common coastal geography can co-exist and co-participate in climate change governance. © 2023, The Author(s), under exclusive licence to Springer Nature B.V. |
| Main drivers of marine heat waves in the eastern South Pacific | Frontiers in Marine Science | Carrasco, D.; Pizarro, O.; Jacques-Coper, M.; Narváez, D. | 2023 | Zonas Costeras | 10.3389/fmars.2023.1129276 | https://doi.org/10.3389/fmars.2023.1129276 | art: 1129276 | Vol: 10 | 2296-7745 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | During the last decades, marine heat waves (MHWs) have increased in frequency and duration, with important impacts on marine ecosystems. This trend has been related to rising global sea surface temperatures, which are expected to continue in the future. Here, we analyze the main characteristics and possible drivers of MHWs in the eastern South Pacific off Chile. Our results show that MHWs usually exhibit spatial extensions on the order of 103-104 km2, temperature anomalies in the mixing layer between 1 and 1.3°C, and durations of 10 to 40 days, with exceptional events lasting several months. In this region, MHW are closely related to the ENSO cycles, in such a way that El Niño and, to a lesser extent, La Niña events increase the probability of high intensity and extreme duration MHWs. To analyze the MHW drivers, we use the global ocean reanalysis GLORYS2 to perform a heat budget in the surface mixed layer. We find that most events are dominated by diminished heat loss –associated with reduced evaporation– and enhanced insolation; thus, this group is called ASHF (for air-sea heat fluxes). The second type of MHWs is driven by heat advection, predominantly forced by anomalous eastward surface currents superimposed on a mean westward temperature gradient. The third type of MHWs results from a combination of positive (seaward) anomalies of air-sea heat fluxes and heat advection; this group exhibits the greatest values of spatial extension, intensity, and duration. Copyright © 2023 Carrasco, Pizarro, Jacques-Coper and Narváez. |
| Climatic control of the surface mass balance of the Patagonian Icefields | Cryosphere | Carrasco-Escaff, T.; Rojas, M.; Garreaud, R.; Bozkurt, D.; Schaefer, M. | 2023 | Agua y Extremos; Zonas Costeras; l | 10.5194/tc-17-1127-2023 | https://doi.org/10.5194/tc-17-1127-2023 | 1127-1149 | Vol: 17 Issue: 3 | 1994-0416 | Thomson Reuters ISI (SCIE) | | English | The Patagonian Icefields (Northern and Southern Patagonian Icefield) are the largest ice masses in the Andes Cordillera. Despite its importance, little is known about the main mechanisms that underpin the interaction between these ice masses and climate. Furthermore, the nature of large-scale climatic control over the surface mass variations of the Patagonian Icefields still remains unclear. The main aim of this study is to understand the present-day climatic control of the surface mass balance (SMB) of the Patagonian Icefields at interannual timescales, especially considering large-scale processes. We modeled the present-day (1980-2015) glacioclimatic surface conditions for the southern Andes Cordillera by statistically downscaling the output from a regional climate model (RegCMv4) from a 10km spatial resolution to a 450m resolution grid and then using the downscaled fields as input for a simplified SMB model. Series of spatially averaged modeled fields over the Patagonian Icefields were used to derive regression and correlation maps against fields of climate variables from the ERA-Interim reanalysis. Years of relatively high SMB are associated with the establishment of an anomalous low-pressure center near the Drake Passage, the Drake low, that induces an anomalous cyclonic circulation accompanied with enhanced westerlies impinging on the Patagonian Icefields, which in turn leads to increases in the precipitation and the accumulation over the icefields. Also, the Drake low is thermodynamically maintained by a core of cold air that tends to reduce the ablation. Years of relatively low SMB are associated with the opposite conditions. We found low dependence of the SMB on main atmospheric modes of variability (El Niño-Southern Oscillation, Southern Annular Mode), revealing a poor ability of the associated indices to reproduce the interannual variability of the SMB. Instead, this study highlights the Drake Passage as a key region that has the potential to influence the SMB variability of the Patagonian Icefields. © 2023 The Author(s). |
| Seasonal and Spatially Distributed Viral Metagenomes from Comau Fjord (42°S), Patagonia | Microbiology Resource Announcements | Castro-Nallar, E.; Berríos-Farías, V.; Díez, B.; Guajardo-Leiva, S. | 2023 | Zonas Costeras | 10.1128/mra.00082-23 | https://doi.org/10.1128/mra.00082-23 | 1-5 | Vol: 12 Issue: 4 | 2576-098X | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | English | Viruses are key players in marine environments, affecting food webs and biogeochemical cycles. We present 48 viral metagenomes and 5,656 viral operational taxonomic units (vOTUs) from Comau Fjord, Patagonia (42°S), to understand viral-mediated processes in coastal and estuarine waters. These data represent a spatial (35-km transect, two depths) and seasonal (winter and fall) data set. Copyright © 2023 Castro-Nallar et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license. |
| Spatially and Temporally Explicit Metagenomes and Metagenome-Assembled Genomes from the Comau Fjord (42°S), Patagonia | Microbiology Resource Announcements | Castro-Nallar, E.; Berríos-Farías, V.; Díez, B.; Guajardo-Leiva, S. | 2023 | Zonas Costeras | 10.1128/mra.00059-23 | https://doi.org/10.1128/mra.00059-23 | 1-3 | Vol: 12 Issue: 6 | 2576098X | Thomson Reuters ISI (ESCI) | All Open Access; Gold Open Access | English | Microbes play an important role in coastal and estuarine waters. We present 93 metagenomes and 677 metagenome-assembled genomes (MAGs) from Comau Fjord, Patagonia (42°S), to further understand the microbial dynamics and their response to anthropogenic disturbances. These data represent a spatially (35-km transect) and temporally (2016 to 2019) explicit data set. © 2023 Castro-Nallar et al. |
| Assessment of the RegCM4-CORDEX-CORE performance in simulating cyclones affecting the western coast of South America | Climate Dynamics | Crespo, N.; Reboita, M.; Gozzo, L.; de Jesus, E.; Torres-Alavez, J.; Lagos-Zúñiga, M.; Torrez-Rodriguez, L.; Reale, M.; da Rocha, R. | 2023 | Zonas Costeras | 10.1007/s00382-022-06419-6 | https://doi.org/10.1007/s00382-022-06419-6 | 2041-2059 | Vol: 60 Issue: 7-8 | 0930-7575 | Thomson Reuters ISI (SCIE) | | English | In this study, we assess the performance of the Regional Climate Model version 4 (RegCM4) in simulating the climatology of the cyclones near the west coast of South America. The synoptic evolution and seasonality of these systems are thoroughly investigated. The analyses are based on four simulations from the CORDEX-CORE Southern America (SA) domain, at 0.25° of horizontal resolution: one driven by ERA-Interim and three driven by different GCMs. The reference dataset is represented by ERA5. Cyclones were detected by an objective scheme in the period 1995–2005 and classified in three different classes: (i) Coastal Lows (CLs) and cyclones affecting the coast (CAC) (ii) crossing and (iii) not crossing the Andes. In general, RegCM4 is able to reproduce the climatology of cyclones affecting the western coast of SA. In particular: (i) CLs are shown to be more frequent in austral summer although their frequency is underestimated by the simulations in this season; (ii) CAC not crossing the Andes represent 76% of all CAC and are more frequent in winter, with simulation underestimating their frequency by ~ 22% due to the differences in the simulated upper-level jets, which tend to get weaker (by ~ 5–10 m s− 1) northwards of 30°S; (iii) the frequency of CAC crossing the Andes tends to be overestimated mainly in winter, which is associated with the combination of the stronger upper-level jets and weaker SLP in the simulations, especially southwards of 40°S. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. |
| The intensification of coastal hypoxia off central Chile: Long term and high frequency variability | Frontiers in Earth Science | De La Maza, L.; Farías, L. | 2023 | Zonas Costeras | 10.3389/feart.2022.929271 | https://www.frontiersin.org/articles/10.3389/feart.2022.929271/full | 929271 | Vol: 10 | 2296-6463 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Hypoxia is a phenomenon where dissolved oxygen (DO) is reduced to levels that are low enough to strongly affect ecological and biogeochemical processes. This occurs within the continental shelf off central Chile (36°S), influenced by seasonal coastal upwelling (Spring-Summer). Monthly measurements of DO and other oceanographic variables in the water column (1997−2021) over the 92 m isobath along with high-resolution and near-surface observations (POSAR buoy), are analyzed to examine incidences of hypoxia and understand the physical and biogeochemical processes modulating DO vertical distribution and its temporal variability. On average, the percentage of the water column with DO levels below 89 (hypoxia) and 22 (severe hypoxia) μmol L
−1
reaches 68% (i.e., hypoxic waters are found below 30 m) and 44% (below 50 m depth), respectively, but during the upwelling season, as much as 87% (below 12 m depth) and 81% (below 17 m depth) of the water column exhibits these levels. On the sub-seasonal scale during upwelling season six hypoxic events lasting at least 2 days occur at 10 m depth. There is a strong seasonal correlation between the volume of the seawater presenting hypoxia and upwelling favorable winds. Furthermore, there is a high DO interannual variability partially related to the El Niño Southern Oscillation (ENSO). Over 2 decades, it is estimated that DO concentration in surface and subsurface layers decreases (up to 21 μmol L
−1
decade
−1
) as waters get colder (up to 0.29°C decade
−1
). Remarkably, the volume of hypoxic and severe hypoxic waters over the shelf has increased more than 2 times since 1997 and shows a significant positive correlation with the upwelling index. These preliminary findings indicate that the increase in local DO consumption is partially associated with upwelling intensification. Given the clear evidence of wind intensification in coastal upwelling ecosystems and thus the increase in hypoxic events, the coastal zone may be highly vulnerable to hypoxia, impacting biological resources and biogeochemical cycles. |
| The impact of local and climate change drivers on the formation, dynamics, and potential recurrence of a massive fish-killing microalgal bloom in Patagonian fjord | Science of The Total Environment | Díaz, P.; Pérez-Santos, I.; Basti, L.; Garreaud, R.; Pinilla, E.; Barrera, F.; Tello, A.; Schwerter, C.; Arenas-Uribe, S.; Soto-Riquelme, C.; Navarro, P.; Díaz, M.; Álvarez, G.; Linford, P.; Altamirano, R.; Mancilla-Gutiérrez, G.; Rodríguez-Villegas, C.; Figueroa, R. | 2023 | Agua y Extremos; Zonas Costeras | 10.1016/j.scitotenv.2022.161288 | https://linkinghub.elsevier.com/retrieve/pii/S0048969722083929 | 161288 | Vol: 865 | 00489697 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Harmful algal blooms (HABs) in southern Chile are a serious threat to public health, tourism, artisanal fisheries, and aquaculture in this region. Ichthyotoxic HAB species have recently become a major annual threat to the Chilean salmon farming industry, due to their severe economic impacts. In early austral autumn 2021, an intense bloom of the raphidophyte Heterosigma akashiwo was detected in Comau Fjord, Chilean Patagonia, resulting in a high mortality of farmed salmon (nearly 6000 tons of biomass) within 15 days. H. akashiwo cells were first detected at the head of the fjord on March 16, 2021 (up to 478 cells mL−1). On March 31, the cell density at the surface had reached a maximum of 2 × 105 cells mL−1, with intense brown spots visible on the water surface. Strong and persistent high-pressure anomalies over the southern tip of South America, consistent with the positive phase of the Southern Annular Mode (SAM), resulted in extremely dry conditions, high solar radiation, and strong southerly winds. A coupling of these features with the high water retention times inside the fjord can explain the spatial-temporal dynamics of this bloom event. Other factors, such as the internal local physical uplift process (favored by the north-to-south orientation of the fjord), salt-fingering events, and the uplift of subantarctic deep-water renewal, likely resulted in the injection of nutrients into the euphotic layer, which in turn could have promoted cell growth and thus high microalgal cell densities, such as reached by the bloom. © 2022 Elsevier B.V. |
| Cooling the Coldest Continent The 4 December 2021 Total Solar Eclipse over Antarctica | Bulletin of the American Meteorological Society | Garreaud, R.; Bozkurt, D.; Spangrude, C.; Carrasco-Escaff, T.; Rondanelli, R.; Muñoz, R.; Jubier, X.; Lazzara, M.; Keller, L.; Rojo, P. | 2023 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-22-0272.1 | https://doi.org/10.1175/BAMS-D-22-0272.1 | E2265-E2285 | Vol: 104 Issue: 12 | 00030007 | Thomson Reuters ISI (SCIE) | All Open Access; Bronze Open Access | English | Total solar eclipses (TSEs) are impressive astronomical events that have attracted people’s curiosity since ancient times. Their abrupt alterations to the radiation balance have stimulated studies on “eclipse meteorology,” most of them documenting events in the Northern Hemisphere while only one TSE (23 November 2003) has been described over Antarctica. On 4 December 2021—just a few days before the austral summer solstice—the moon blocked the sun over the austral high latitudes, with the path of totality arching from the Weddell Sea to the Amundsen Sea, thus producing a ∼2-min central TSE. In this work we present high-resolution meteorological observations from Union Glacier Camp (80°S, 83°W), the only location with a working station under totality, and South Pole station. These observations were complemented with meteorological records from 37 surface stations across Antarctica. Notably, the largest cooling (∼5°C) was observed over the East Antarctic dome, where obscurity was ∼85% while many sectors experienced insignificant temperature changes. This heterogenous cooling distribution, at odds with the seemingly homogeneous land surface of Antarctica, is partially captured by a simple radiative model. To further diagnose the effect of the eclipse on the surface meteorology, we ran multiple pairs of simulations (eclipse enabled and disabled) using the Weather Research and Forecasting (WRF) Model. The overall pattern and magnitude of the simulated cooling agree well with the observations and reveal that, in addition to the solar radiation deficit and cloud cover, low-level winds and the height of the planetary boundary layer are key determinants of the temperature changes and their spatial variability. © 2023 American Meteorological Society. This published article is licensed under the terms of the default AMS reuse license. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). |
| Evolution of heatwaves in Chile since 1980 | Weather and Climate Extremes | González-Reyes, Á.; Jacques-Coper, M.; Bravo, C.; Rojas, M.; Garreaud, R. | 2023 | Agua y Extremos; Zonas Costeras; l | 10.1016/j.wace.2023.100588 | https://doi.org/10.1016/j.wace.2023.100588 | art100588 | Vol: 41 | 22120947 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Heatwaves (HWs) are highly dangerous threats to human and ecosystem health, as well as to many economic sectors around the world. In the present work focused on Chile, we use a high-resolution (∼5 km) gridded product (CR2Met v2.0) to evaluate the spatiotemporal distribution and trends of HWs. We analyze daily maximum temperatures (Tx) from late austral spring to early autumn (November to March) to evaluate the HWs behavior during 1980–2020, using three criteria: i) three consecutive days with Tx > 30°C, ii) three consecutive days with Tx > 90th percentile (P90), and iii) three consecutive days with Tx > 95th percentile (P95). We validated our results using HWs statistics based on eighteen official meteorological stations; this procedure revealed a coherence with gridded data mainly over the Central Valley and the Andes. Using the P90 threshold, we found upward trends across the Andes between 20° and 36°S (>1 events per decade), and in the Central Valley between 34° - 43°S (>0.75 events per decade). In addition, using the P90 and P95 thresholds, HWs exhibit upward trends (>1 and 0.5 events per decade, respectively) throughout most of Chile, including Andes and Patagonia. Moreover, using all thresholds, we found an increase in HW frequency during the 2011–2020 megadrought period (ranging from 1 to 4 HWs events/decade) in comparison to the previous period (1980–2010). Meteorological factors such as an increase in the frequency of Puelche (Föhn-like) winds are proposed as an amplifying mechanism of HWs in South-Central Chile. © 2023 |
| A First Insight into the Microbial and Viral Communities of Comau Fjord—A Unique Human-Impacted Ecosystem in Patagonia (42° S) | Microorganisms | Guajardo-Leiva, S.; Mendez, K.; Meneses, C.; Díez, B.; Castro-Nallar, E. | 2023 | Zonas Costeras | 10.3390/microorganisms11040904 | https://doi.org/10.3390/microorganisms11040904 | art: 904 | Vol: 11 Issue: 4 | 2076-2607 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | While progress has been made in surveying the oceans to understand microbial and viral communities, the coastal ocean and, specifically, estuarine waters, where the effects of anthropogenic activity are greatest, remain partially understudied. The coastal waters of Northern Patagonia are of interest since this region experiences high-density salmon farming as well as other disturbances such as maritime transport of humans and cargo. Here, we hypothesized that viral and microbial communities from the Comau Fjord would be distinct from those collected in global surveys yet would have the distinctive features of microbes from coastal and temperate regions. We further hypothesized that microbial communities will be functionally enriched in antibiotic resistance genes (ARGs) in general and in those related to salmon farming in particular. Here, the analysis of metagenomes and viromes obtained for three surface water sites showed that the structure of the microbial communities was distinct in comparison to global surveys such as the Tara Ocean, though their composition converges with that of cosmopolitan marine microbes belonging to Proteobacteria, Bacteroidetes, and Actinobacteria. Similarly, viral communities were also divergent in structure and composition but matched known viral members from North America and the southern oceans. Microbial communities were functionally enriched in ARGs dominated by beta-lactams and tetracyclines, bacitracin, and the group macrolide–lincosamide–streptogramin (MLS) but were not different from other communities from the South Atlantic, South Pacific, and Southern Oceans. Similarly, viral communities were characterized by exhibiting protein clusters similar to those described globally (Tara Oceans Virome); however, Comau Fjord viromes displayed up to 50% uniqueness in their protein content. Altogether, our results indicate that microbial and viral communities from the Comau Fjord are a reservoir of untapped diversity and that, given the increasing anthropogenic impacts in the region, they warrant further study, specifically regarding resilience and resistance against antimicrobials and hydrocarbons. © 2023 by the authors. |
| Synoptic-to-intraseasonal atmospheric modulation of phytoplankton biomass in the inner sea of Chiloé, Northwest Patagonia (42.5°-43.5°S, 72.5°-74°W), Chile | Frontiers in Marine Science | Jacques-Coper, M.; Segura, C.; De La Torre, M.; Valdebenito Muñoz, P.; Vásquez, S.; Narváez, D. | 2023 | Zonas Costeras | 10.3389/fmars.2023.1160230 | https://doi.org/10.3389/fmars.2023.1160230 | 1160230 | Vol: 10 | 2296-7745 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | The Inner Sea of Chiloé (ISC) in northwestern Patagonia has experienced large harmful algal blooms in the past decade, impacting human health and affecting the large aquaculture industry of the region. Thus, the investigation of factors favouring regional phytoplankton growth are of particular interest. Analysing the synoptic-to-intraseasonal variability, we explore changes in phytoplankton biomass in southern ISC (S-ISC, 42.5°-43.5°S, 72.5°-74°W) and their concurrent mesoscale and large-scale meteorological and oceanographic conditions. We use high-resolution satellite normalized fluorescence line height (nFLH) and chlorophyll-a (CHL-A) from the MODIS-Aqua sensor as proxies for phytoplankton biomass, besides oceanic and atmospheric variables derived from various remote-sensing sources and atmospheric fields from the ERA5 reanalysis. Specifically, we focus on high phytoplankton biomass events HBEs, which are defined as those cases when intraseasonal nFLH anomaly (nFLH’) exceeds the 95th percentile threshold. Each event was characterised by its first date of occurrence (called day 0). We detected 16 HBE between 2003 and 2019 in S-ISC. HBEs tend to occur under the influence of a mid-latitude migratory anticyclone that induce persistent cloudless conditions preceding day 0, leading to enhanced photosynthetically active radiation (PAR) starting around day -8, and positive sea surface temperature (SST) anomalies between days -4 and +4. We hypothesise that HBEs are mainly modulated by i) mixing and advection that could contribute to a greater availability of nutrients in the upper sea layers before the onset of the anticyclonic anomalies; and ii) increased thermal stratification related to positive PAR and SST anomalies that would promote phytoplankton growth during the anticyclonic regime. Furthermore, we show that the Madden-Julian Oscillation modulates the frequency of nFLH’ and thus of HBEs, a result that suggests an enhanced predictability of these cases. |
| Distribution and Activity of Sulfur-Metabolizing Bacteria along the Temperature Gradient in Phototrophic Mats of the Chilean Hot Spring Porcelana | Microorganisms | Konrad, R.; Vergara-Barros, P.; Alcorta, J.; Alcamán-Arias, M.; Levicán, G.; Ridley, C.; Díez, B. | 2023 | Zonas Costeras | 10.3390/microorganisms11071803 | https://doi.org/10.3390/microorganisms11071803 | art1803 | Vol: 11 Issue: 7 | 2076-2607 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | In terrestrial hot springs, some members of the microbial mat community utilize sulfur chemical species for reduction and oxidization metabolism. In this study, the diversity and activity of sulfur-metabolizing bacteria were evaluated along a temperature gradient (48–69 °C) in non-acidic phototrophic mats of the Porcelana hot spring (Northern Patagonia, Chile) using complementary meta-omic methodologies and specific amplification of the aprA (APS reductase) and soxB (thiosulfohydrolase) genes. Overall, the key players in sulfur metabolism varied mostly in abundance along the temperature gradient, which is relevant for evaluating the possible implications of microorganisms associated with sulfur cycling under the current global climate change scenario. Our results strongly suggest that sulfate reduction occurs throughout the whole temperature gradient, being supported by different taxa depending on temperature. Assimilative sulfate reduction is the most relevant pathway in terms of taxonomic abundance and activity, whereas the sulfur-oxidizing system (Sox) is likely to be more diverse at low rather than at high temperatures. Members of the phylum Chloroflexota showed higher sulfur cycle-related transcriptional activity at 66 °C, with a potential contribution to sulfate reduction and oxidation to thiosulfate. In contrast, at the lowest temperature (48 °C), Burkholderiales and Acetobacterales (both Pseudomonadota, also known as Proteobacteria) showed a higher contribution to dissimilative sulfate reduction/oxidation as well as to thiosulfate metabolism. Cyanobacteriota and Planctomycetota were especially active in assimilatory sulfate reduction. Analysis of the aprA and soxB genes pointed to members of the order Burkholderiales (Gammaproteobacteria) as the most dominant and active along the temperature gradient for these genes. Changes in the diversity and activity of different sulfur-metabolizing bacteria in photoautotrophic microbial mats along a temperature gradient revealed their important role in hot spring environments, especially the main primary producers (Chloroflexota/Cyanobacteriota) and diazotrophs (Cyanobacteriota), showing that carbon, nitrogen, and sulfur cycles are highly linked in these extreme systems. © 2023 by the authors. |
| Spatio-temporal multidisciplinary analysis of socio-environmental conditions to explore the COVID-19 early evolution in urban sites in South America | Heliyon | Mantilla Caicedo, G.; Rusticucci, M.; Suli, S.; Dankiewicz, V.; Ayala, S.; Caiman Peñarete, A.; Díaz, M.; Fontán, S.; Chesini, F.; Jiménez-Buitrago, D.; Barreto Pedraza, L.; Barrera, F. | 2023 | Zonas Costeras | 10.1016/j.heliyon.2023.e16056 | https://doi.org/10.1016/j.heliyon.2023.e16056 | art: e16056 | Vol: 9 Issue: 5 | 2405-8440 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access; Green Open Access | English | This study aimed to analyse how socio-environmental conditions affected the early evolution of COVID-19 in 14 urban sites in South America based on a spatio-temporal multidisciplinary approach. The daily incidence rate of new COVID-19 cases with symptoms as the dependent variable and meteorological-climatic data (mean, maximum, and minimum temperature, precipitation, and relative humidity) as the independent variables were analysed. The study period was from March to November of 2020. We inquired associations of these variables with COVID-19 data using Spearman's non-parametric correlation test, and a principal component analysis considering socio economic and demographic variables, new cases, and rates of COVID-19 new cases. Finally, an analysis using non-metric multidimensional scale ordering by the Bray-Curtis similarity matrix of meteorological data, socio economic and demographic variables, and COVID-19 was performed. Our findings revealed that the average, maximum, and minimum temperatures and relative humidity were significantly associated with rates of COVID-19 new cases in most of the sites, while precipitation was significantly associated only in four sites. Additionally, demographic variables such as the number of inhabitants, the percentage of the population aged 60 years and above, the masculinity index, and the GINI index showed a significant correlation with COVID-19 cases. Due to the rapid evolution of the COVID-19 pandemic, these findings provide strong evidence that biomedical, social, and physical sciences should join forces in truly multidisciplinary research that is critically needed in the current state of our region. © 2023 |
| Kanamycin treatment in the pre-symptomatic stage of a Drosophila PD model prevents the onset of non-motor alterations | Neuropharmacology | Molina-Mateo, D.; Valderrama, B.; Zárate, R.; Hidalgo, S.; Tamayo-Leiva, J.; Soto-González, A.; Guerra-Ayala, S.; Arriagada-Vera, V.; Oliva, C.; Diez, B.; Campusano, J. | 2023 | Zonas Costeras | 10.1016/j.neuropharm.2023.109573 | https://doi.org/10.1016/j.neuropharm.2023.109573 | art: 109573 | Vol: 236 | 0028-3908 | Thomson Reuters ISI (SCIE) | | English | Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor alterations, which is preceded by a prodromal stage where non-motor symptoms are observed. Over recent years, it has become evident that this disorder involves other organs that communicate with the brain like the gut. Importantly, the microbial community that lives in the gut plays a key role in this communication, the so-called microbiota-gut-brain axis. Alterations in this axis have been associated to several disorders including PD. Here we proposed that the gut microbiota is different in the presymptomatic stage of a Drosophila model for PD, the Pink1B9 mutant fly, as compared to that observed in control animals. Our results show this is the case: there is basal dysbiosis in mutant animals evidenced by substantial difference in the composition of midgut microbiota in 8–9 days old Pink1B9 mutant flies as compared with control animals. Further, we fed young adult control and mutant flies kanamycin and analyzed motor and non-motor behavioral parameters in these animals. Data show that kanamycin treatment induces the recovery of some of the non-motor parameters altered in the pre-motor stage of the PD fly model, while there is no substantial change in locomotor parameters recorded at this stage. On the other hand, our results show that feeding young animals the antibiotic, results in a long-lasting improvement of locomotion in control flies. Our data support that manipulations of gut microbiota in young animals could have beneficial effects on PD progression and age-dependent motor impairments. © 2023 Elsevier Ltd |
| Prokaryotic community dynamics and nitrogen-cycling genes in an oxygen-deficient upwelling system during La Niña and El Niño conditions | Environmental Microbiology | Pajares, S.; Merino-Ibarra, M.; Farías, L. | 2023 | Zonas Costeras | 10.1111/1462-2920.16362 | https://doi.org/10.1111/1462-2920.16362 | 1281-1299 | Vol: 25 | 1462-2912 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | Dissolved oxygen regulates microbial distribution and nitrogen cycling and, therefore, ocean productivity and Earth's climate. To date, the assembly of microbial communities in relation to oceanographic changes due to El Niño Southern Oscillation (ENSO) remains poorly understood in oxygen minimum zones (OMZ). The Mexican Pacific upwelling system supports high productivity and a permanent OMZ. Here, the spatiotemporal distribution of the prokaryotic community and nitrogen-cycling genes was investigated along a repeated transect subjected to varying oceanographic conditions associated with La Niña in 2018 and El Niño in 2019. The community was more diverse during La Niña and in the aphotic OMZ, dominated by the Subtropical Subsurface water mass, where the highest abundances of nitrogen-cycling genes were found. The largest proportion of the Gulf of California water mass during El Niño provided warmer, more oxygenated, and nutrient-poor waters towards the coast, leading to a significant increase of Synechococcus in the euphotic layer compared with the opposite conditions during La Niña. These findings suggest that prokaryotic assemblages and nitrogen genes are linked to local physicochemical conditions (e.g. light, oxygen, nutrients), but also to oceanographic fluctuations associated with ENSO phases, indicating the crucial role of climate variability in microbial community dynamics in this OMZ. © 2023 The Authors. Environmental Microbiology published by Applied Microbiology International and John Wiley & Sons Ltd. |
| Hydrological connections in a glaciated Andean catchment under permafrost conditions (33°S) | Journal of Hydrology: Regional Studies | Pereira, S.; Díez, B.; Cifuentes-Anticevic, J.; Leray, S.; Fernandoy, F.; Marquardt, C.; Lambert, F. | 2023 | Ciudades Resilientes; Zonas Costeras | 10.1016/j.ejrh.2022.101311 | https://www.sciencedirect.com/science/article/pii/S221458182200324X | 101311 | Vol: 45 | 22145818 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Fresh water supply is critical along the Andes, where drought conditions over the past decade are projected to persist. At high Andean headwater catchments, frozen ground conditions are assumed to modulate groundwater flow paths and their hydrological signals at different timescales. However, knowledge of hydrological connections in subtropical Andean catchments is still very sparse. This study assessed hydrological connections and their impacts on groundwater contribution to baseflow in a headwater proglacial aquifer located in central Chile at 33° S and 3600 m a.s.l. We collected and analyzed snow, glacial stream, and groundwater spring water samples between 2019 and 2021. We combined of water isotope and metagenomic proxies with the hydraulic parameterization of the catchment to deliver mean transit time distributions through the proglacial aquifer. The new hydrological insights for the region include the finding that groundwater spring signals delivered sub-decadal transit times, implying likely origins from glacial or interstitial ice. Additionally, the stable isotope signature showed that groundwater consistently differs from snow and surface runoff. The 16S rRNA metabarcoding analyses demonstrated the presence of psychrophilic microorganisms in groundwater springs, supporting the idea of a late warm-season activation of interstitial ice due to thawing events associated with a differential relative-abundance of specific cryophilic bacteria. Finally, our results suggest hydrological connections and dampening timeframes between glaciers, proglacial areas, and groundwater springs, most likely from thawing sources. © 2023 The Authors |
| On the interpretation of changes in the subtropical oxygen minimum zone volume off Chile during two La Niña events (2001 and 2007) | Frontiers in Marine Science | Pizarro-Koch, M.; Pizarro, O.; Dewitte, B.; Montes, I.; Paulmier, A.; Garçon, V.; Sepulveda, H.; Corredor-Acosta, A.; Aguirre, C.; Ramos, M. | 2023 | Zonas Costeras | 10.3389/fmars.2023.1155932 | http://hdl.handle.net/20.500.12816/5436 | art1155932 | Vol: 10 | 22967745 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration is extremely low. They are suspected to be expanding in response to global warming. However, currently, the mechanisms by which OMZ varies in response to climate variability are still uncertain. Here, the variability of the subtropical OMZ off central Chile of a regional coupled physical–biogeochemical regional model simulation was analyzed for the period 2000–2008, noting that its fluctuations were significant despite the relatively weak amplitude of the El Niño/Southern Oscillation (ENSO). In particular, the interannual variability in the OMZ volume (OMZVOL, defined as the volume with dissolved oxygen concentration (DO) ≤ 45μM) was approximately 38% larger than that of the seasonal cycle, with maximum and minimum anomalies of OMZVOL taking place during two cold La Niña (LN) years (2001 and 2007). The model analyses further reveal that these anomalies resulted from a combined effect of changes in (1) the oxygen-poor waters poleward transport by the Peru–Chile undercurrent (PCUC), (2) the intensity of quasi-zonal jets influencing the transport of water to and from the OMZ, and (3) the zonal DO transport related to mesoscale eddy activity. Specifically, the interannual variability of the PCUC modulated primarily the DO contents of the OMZ core [(DO) ≤ 20μM] and secondarily the OMZVOL, while cross-shore DO transport by the zonal jets and the eddy fluxes played a major role in ventilating and shaping the offshore extent of the OMZ. When the OMZVOL was maximum (minimum), the PCUC transport was slightly increased (reduced), which was associated with a reduction (increase) in the ventilation of the OMZ through negative (positive) anomalies of zonal advection and DO eddy fluxes. Our results demonstrate that significant natural interannual variability in the subtropical OMZ off Chile originates from the interplay between oceanic equatorial teleconnection (PCUC transport) and local non-linear dynamics (the zonal jets and mesoscale eddies). Copyright © 2023 Pizarro-Koch, Pizarro, Dewitte, Montes, Paulmier, Garçon, Sepulveda, Corredor-Acosta, Aguirre and Ramos. |
| The role of atmospheric rivers in rainfall-induced landslides: A study from the Elqui valley | Journal of Arid Environments | Rutllant, J.; Matus, F.; Rudloff, V.; Rondanelli, R. | 2023 | Zonas Costeras | 10.1016/j.jaridenv.2023.105016 | https://doi.org/10.1016/j.jaridenv.2023.105016 | 105016 | Vol: 216 | 01401963 | Thomson Reuters ISI (SCIE) | All Open Access; Hybrid Gold Open Access | English | The purpose of the present study is to explore the synoptic-scale atmospheric circulation and water vapor transport that contribute to triggering landslides in the mid-Elqui basin (30°S, 70.5°W) since the early 20th century. A total of 12 storms during the modern period (1957–2017) were identified from various sources and analyzed using ERA5 Reanalysis data. An additional set of eight storms was included and characterized using 20th Century Reanalysis data. The results reveal that high-amplitude, deep troughs extending into the subtropics off the west coast of South America are ubiquitous in these storms. Maximum integrated water vapor transport from the northwest (NW) or west-northwest (WNW) was observed on the coast (25–30°S), with values sometimes exceeding 300 kg s-1 m-1, often reaching more than five standard deviations above the mean. Atmospheric rivers near the study region were found to be involved in all 12 modern landslide-producing storms. Moreover, most storms occur during the warm phase of the El Niño–Southern Oscillation (ENSO) and/or phases 7–8–1 of the Madden–Julian Oscillation (MJO). Backward-trajectory analyses indicate that in all but one of the modern storms, water vapor transport originated in the Central Tropical Pacific, where ocean warming characterizes the convective phases of ENSO and/or MJO. © 2023 The Authors |
| Volatile organic compounds measured by proton transfer reaction mass spectrometry over the complex terrain of Quintero Bay, Central Chile | Environmental Pollution | Seguel, R.; Garreaud, R.; Muñoz, R.; Bozkurt, D.; Gallardo, L.; Opazo, C.; Jorquera, H.; Castillo, L.; Menares, C. | 2023 | Agua y Extremos; Ciudades Resilientes; Zonas Costeras | 10.1016/j.envpol.2023.121759 | https://doi.org/10.1016/j.envpol.2023.121759 | 121759 | Vol: 330 | 02697491 | Thomson Reuters ISI (SCIE) | | English | This research provides new evidence regarding the different kinds of air quality episodes, and their underlying mechanisms, that frequently impact the urban area of Quintero Bay in Central Chile, which is located along complex coastal terrain and is surrounded by industries. The monitoring campaign was carried out in January 2022 and encompassed two distinctive meteorological regimes. The first part of the month was dominated by a coastal low centered to the south of Quintero, which resulted in prevailing northerly flow (or weak southerlies) and a deep cloud-topped marine boundary layer. After a 2–3-day transition, the latter collapsed, and a clear-sky regime ensued, which was characterized by a shallow boundary layer and strong southerly winds during the daytime that lasted until the end of the campaign. By using proton transfer reaction time of flight mass spectrometry (PTR–TOF–MS) at a high temporal resolution (1 s), we measured high levels of volatile organic compounds (VOCs) during air quality episodes in real time. The episodes detected were associated with different prevailing meteorological regimes, suggesting that different point sources were involved. In the first episode, propene/cyclopropane, butenes, benzene, toluene and ethylbenzene/xylenes were associated with north and northwesterly weak winds. Complaints associated with hydrocarbon odor were reported. The pollution originated from industrial and petrochemical units located to the north of Quintero, which transport and store natural gas, liquified petroleum gas and oil. The second episode was linked to an oil refinery located south of our measurement site. In this case, high levels of phenol, furan and cresols occurred under strong southwesterly winds. During this event, headaches and dizziness were reported. By contrast, the levels of other aromatic compounds (benzene, toluene, ethylbenzene/xylenes) were lower than in the first air pollution episode. © 2023 Elsevier Ltd |
| Large-scale and regional climatic influences on surface temperature and precipitation in the South Shetland Islands, northern Antarctic Peninsula | Anais da Academia Brasileira de Ciencias | Torres, C.; Bozkurt, D.; Arigony-Neto, J. | 2023 | Zonas Costeras | 10.1590/0001-3765202320230685 | https://doi.org/10.1590/0001-3765202320230685 | arte20230685 | Vol: 95 | 00013765 | Thomson Reuters ISI (SCIE) | All Open Access; Gold Open Access | English | Using data from SCAR observations, ERA5 reanalysis, and regional climate model simulations (RACMO), we examined the influence of large-and regional-scale climate forcing on temperature and precipitation variations in the South Shetland Islands (SSI). Specifically, we focused on understanding how regional climate indices influence the temporal variability of temperature and precipitation on the SSI. Our findings indicate that both large-and regional-scale climate indices significantly impact the interannual and seasonal temperature variability in the SSI. For instance, the Amundsen Sea Low, characterised by low-pressure systems over the Amundsen Sea, and sea ice extent in the northwestern part of the Weddell Sea, exert a strong influence on temperature variability (r from-0.64 to-0.87; p < 0.05). In contrast, precipitation variability in this region is primarily controlled by regional climatic indices. Particularly, anomalies in atmospheric and surface pressure over the Drake Passage region strongly regulate the interannual variability of precipitation in the SSI (r from-0.46 to-0.70; p < 0.05). Large-scale climatic indices demonstrate low but statistically significant correlations, including the Southern Annular Mode and deep convection in the central tropical Pacific. Given the importance of temperature and precipitation in the glacier changes, we recommend assessing the impact of the Drake region on SSI glaciers. © 2023, Academia Brasileira de Ciencias. All rights reserved. |
| Surface Ammonia-Oxidizer Abundance During the Late Summer in the West Antarctic Coastal System | Frontiers in Microbiology | Alcamán-Arias, M.; Cifuentes-Anticevic, J.; Díez, B.; Testa, G.; Troncoso, M.; Bello, E.; Farías, L. | 2022 | Zonas Costeras | 10.3389/fmicb.2022.821902 | https://www.frontiersin.org/articles/10.3389/fmicb.2022.821902/full | 821902 | Vol: 13 | 1664-302X | Thomson Reuters ISI (SCIE) | | English | Marine ammonia oxidizers that oxidize ammonium to nitrite are abundant in polar waters, especially during the winter in the deeper mixed-layer of West Antarctic Peninsula (WAP) waters. However, the activity and abundance of ammonia-oxidizers during the summer in surface coastal Antarctic waters remain unclear. In this study, the ammonia-oxidation rates, abundance and identity of ammonia-oxidizing bacteria (AOB) and archaea (AOA) were evaluated in the marine surface layer (to 30 m depth) in Chile Bay (Greenwich Island, WAP) over three consecutive late-summer periods (2017, 2018, and 2019). Ammonia-oxidation rates of 68.31 nmol N L
−1
day
−1
(2018) and 37.28 nmol N L
−1
day
−1
(2019) were detected from illuminated 2 m seawater incubations. However, high ammonia-oxidation rates between 267.75 and 109.38 nmol N L
−1
day
−1
were obtained under the dark condition at 30 m in 2018 and 2019, respectively. During the late-summer sampling periods both stratifying and mixing events occurring in the water column over short timescales (February–March). Metagenomic analysis of seven nitrogen cycle modules revealed the presence of ammonia-oxidizers, such as the Archaea
Nitrosopumilus
and the Bacteria
Nitrosomonas
and
Nitrosospira
, with AOA often being more abundant than AOB. However, quantification of specific
amo
A gene transcripts showed number of AOB being two orders of magnitude higher than AOA, with
Nitrosomonas
representing the most transcriptionally active AOB in the surface waters. Additionally,
Candidatus
Nitrosopelagicus and
Nitrosopumilus
, phylogenetically related to surface members of the NP-ε and NP-γ clades respectively, were the predominant AOA. Our findings expand the known distribution of ammonium-oxidizers to the marine surface layer, exposing their potential ecological role in supporting the marine Antarctic system during the productive summer periods. |
| Antarctic Polyester Hydrolases Degrade Aliphatic and Aromatic Polyesters at Moderate Temperatures | Applied and Environmental Microbiology | Blázquez-Sánchez, P.; Engelberger, F.; Cifuentes-Anticevic, J.; Sonnendecker, C.; Griñén, A.; Reyes, J.; Díez, B.; Guixé, V.; Richter, P.; Zimmermann, W.; Ramírez-Sarmiento, C. | 2022 | Zonas Costeras | 10.1128/AEM.01842-21 | https://journals.asm.org/doi/10.1128/AEM.01842-21 | e01842-21 | Vol: 88 Issue: 1 | 0099-2240, 1098-5336 | Thomson Reuters ISI (SCIE) | | English | A myriad of consumer products contains polyethylene terephthalate (PET), a plastic that has accumulated as waste in the environment due to its long-term stability and poor waste management. One promising solution is the enzymatic biodegradation of PET, with most known enzymes only catalyzing this process at high temperatures.
,
ABSTRACT
Polyethylene terephthalate (PET) is one of the most widely used synthetic plastics in the packaging industry, and consequently has become one of the main components of plastic waste found in the environment. However, several microorganisms have been described to encode enzymes that catalyze the depolymerization of PET. While most known PET hydrolases are thermophilic and require reaction temperatures between 60°C and 70°C for an efficient hydrolysis of PET, a partial hydrolysis of amorphous PET at lower temperatures by the polyester hydrolase
Is
PETase from the mesophilic bacterium
Ideonella sakaiensis
has also been reported. We show that polyester hydrolases from the Antarctic bacteria
Moraxella
sp. strain TA144 (Mors1) and
Oleispira antarctica
RB-8 (OaCut) were able to hydrolyze the aliphatic polyester polycaprolactone as well as the aromatic polyester PET at a reaction temperature of 25°C. Mors1 caused a weight loss of amorphous PET films and thus constitutes a PET-degrading psychrophilic enzyme. Comparative modeling of Mors1 showed that the amino acid composition of its active site resembled both thermophilic and mesophilic PET hydrolases. Lastly, bioinformatic analysis of Antarctic metagenomic samples demonstrated that members of the
Moraxellaceae
family carry candidate genes coding for further potential psychrophilic PET hydrolases.
IMPORTANCE
A myriad of consumer products contains polyethylene terephthalate (PET), a plastic that has accumulated as waste in the environment due to its long-term stability and poor waste management. One promising solution is the enzymatic biodegradation of PET, with most known enzymes only catalyzing this process at high temperatures. Here, we bioinformatically identified and biochemically characterized an enzyme from an Antarctic organism that degrades PET at 25°C with similar efficiency to the few PET-degrading enzymes active at moderate temperatures. Reasoning that Antarctica harbors other PET-degrading enzymes, we analyzed available data from Antarctic metagenomic samples and successfully identified other potential enzymes. Our findings contribute to increasing the repertoire of known PET-degrading enzymes that are currently being considered as biocatalysts for the biological recycling of plastic waste. |
| Callampas of disaster: negotiations and struggles for the commons under forestry hegemony in Chile | Community Development Journal | Cid-Aguayo, B.; Krstulovic-Matus, J.; Carrasco Henríquez, N.; Mella-Moraga, V.; Oñate Vargas, D. | 2022 | Zonas Costeras | 10.1093/cdj/bsac030 | https://academic.oup.com/cdj/advance-article/doi/10.1093/cdj/bsac030/6762889 | bsac030 | Vol: 58 | 0010-3802, 1468-2656 | Thomson Reuters ISI (SSCI) | | English | The massive planting of exotic species under the so-called forestry model has dramatically transformed the landscapes of south-central Chile, replacing diverse agricultural, livestock and forest landscapes with forest monocultures, which are highly water-consuming and prone to massive fires. This has meant a productive simplification, and peasant communities have been displaced and stripped of their traditional ways of life. However, in this landscape of disaster, biotic communities of fungi have flourished, and with them human communities of collectors have learned to sustain themselves in a monocultural and privatized scenario. This paper is based on a multi-local ethnographic approach, built upon 26 semi-structured interviews, participant observation, social mapping, creating a calendar and a trend line. The text documents the processes of two communities affected by massive fires which have developed organization, agencies and practices. Mushrooms (callampas in Chilean Spanish) are claimed as a common good derived from the forestry model, claiming access to their use and usufruct of land belonging to forestry companies. They have also developed local governance systems for the care and better use of this new resource for common use. Forestry companies, for their part, try to subsume these practices in their territorial governance processes, disputing these commons’ meaning and purpose. Both cases contribute to empirically address the central thesis of this article, according to which communalization exercises within contexts of capitalist expansion constitute responses of survival, resistance and adaptation in landscapes transformed and devastated by extractivist industries. |
| Impact of biomass burning and stratospheric intrusions in the remote South Pacific Ocean troposphere | Atmospheric Chemistry and Physics | Daskalakis, N.; Gallardo, L.; Kanakidou, M.; Nüß, J.; Menares, C.; Rondanelli, R.; Thompson, A.; Vrekoussis, M. | 2022 | Ciudades Resilientes; Zonas Costeras | 10.5194/acp-22-4075-2022 | https://acp.copernicus.org/articles/22/4075/2022/ | 4075-4099 | Vol: 22 Issue: 6 | 1680-7324 | Thomson Reuters ISI (SCIE) | | English | Abstract. The ozone mixing ratio spatiotemporal variability in the pristine South Pacific Ocean is studied, for the first time, using 21-year-long ozone (O3) records from the entire southern tropical and subtropical Pacific between 1994 and 2014. The analysis considered regional O3 vertical observations from ozonesondes, surface carbon monoxide (CO) observations from flasks, and three-dimensional chemistry-transport model simulations of the global troposphere. Two 21-year-long numerical simulations, with and without biomass burning emissions, were performed to
disentangle the importance of biomass burning relative to stratospheric
intrusions for ambient ozone levels in the region. Tagged tracers of O3 from the stratosphere and CO from various biomass burning regions have been used to track the impact of these different regions on the southern tropical Pacific O3 and CO levels. Patterns have been analyzed based on atmospheric dynamics variability. Considering the interannual variability in the observations, the model can
capture the observed ozone gradients in the troposphere with a positive bias of 7.5 % in the upper troposphere/lower stratosphere (UTLS) as well as near the surface. Remarkably, even the most pristine region of the global ocean is affected by distant biomass burning emissions by convective outflow through the mid and high troposphere and subsequent subsidence over the pristine oceanic region. Therefore, the biomass burning contribution to
tropospheric CO levels maximizes in the UTLS. The Southeast Asian open fires have been identified as the major contributing source to CO from biomass burning in the tropical South Pacific, contributing on average for the study period about 8.5 and 13 ppbv of CO at Rapa Nui and Samoa,
respectively, at an altitude of around 12 km during the burning season in
the spring of the Southern Hemisphere. South America is the second-most important biomass burning source region that influences the study area. Its
impact maximizes in the lower troposphere (6.5 ppbv for Rapa Nui and 3.8 ppbv for Samoa). All biomass burning sources contribute about 15–23 ppbv of CO at Rapa Nui and Samoa and account for about 25 % of the total CO in the entire troposphere of the tropical and subtropical South Pacific. This impact is also seen on tropospheric O3, to which biomass burning O3 precursor emissions contribute only a few ppbv during the burning period, while the stratosphere–troposphere exchange is the most important source of O3 for the mid troposphere of the South Pacific Ocean, contributing about 15–20 ppbv in the subtropics. |
| Atmospheric rivers drive exceptional Saharan dust transport towards Europe | Atmospheric Research | Francis, D.; Fonseca, R.; Nelli, N.; Bozkurt, D.; Picard, G.; Guan, B. | 2022 | Zonas Costeras | 10.1016/j.atmosres.2021.105959 | https://linkinghub.elsevier.com/retrieve/pii/S0169809521005159 | 105959 | Vol: 266 | 0169-8095 | Thomson Reuters ISI (SCIE) | | English | This study highlights the occurrence of atmospheric rivers (ARs) over northwest Africa towards Europe, which were accompanied by intense episodes of Saharan dust transport all the way to Scandinavia, in the winter season. Using a combination of observational and reanalysis data, we investigate two extreme dusty AR events in February 2021 and assess their impact on snow melt in the Alps. The warm, moist, and dusty air mass (spatially-averaged 2-meter temperature and water vapour mixing ratio anomalies of up to 8 K and 3 g kg−1, and aerosol optical depths and dust loadings of up to 0.85 and 11 g m−2, respectively) led to a 50% and 40% decrease in snow depth and surface albedo, respectively, in less than one month during the winter season. ARs over northwest Africa show increasing trends over the past 4 decades, with 78% of AR events associated with severe dust episodes over Europe. © 2021 The Authors |
| Climate change-related risks and adaptation potential in Central and South America during the 21st century | Environmental Research Letters | Hagen, I.; Huggel, C.; Ramajo, L.; Chacón, N.; Ometto, J.; Postigo, J.; Castellanos, E. | 2022 | Zonas Costeras | 10.1088/1748-9326/ac5271 | https://iopscience.iop.org/article/10.1088/1748-9326/ac5271 | 033002 | Vol: 17 Issue: 3 | 1748-9326 | | | English | Abstract
Climate-related risks in Central and South America have received increased attention and concern in science and policy, but an up-to-date comprehensive review and synthesis of risks and adaptation potential is currently missing. For this paper we evaluated over 200 peer-reviewed articles and grey literature documents published since 2012. We found that climate change in Central and South America during the 21st century may increase the risk to severe levels for the following topical risk clusters: (a) Food insecurity; (b) Floods and landslides; (c) Water scarcity; (d) Epidemics of vector-borne diseases; (e) Amazon Forest biome shift; (f). Coral bleaching; (g) Coastal risks of sea level rise, storm surges and erosion; (h) Systemic failure due to cascading impacts of hazards and epidemics. Our synthesis also identified feasible adaptation measures for each risk. The impacts of the risks will be heterogeneous throughout the region, with rural communities, Indigenous peoples, Afro-Latin Americans, women, disabled people, and migrants identified as being the most severely affected. We refer to a number of adaptation options for each risk. However, unabated climate change together with low adaptive capacity will strictly limit adaptation options. Immediate strengthening of policies for building adaptive capacity and increase of research on the risk-adaptation nexus in Central and South America are paramount. Our findings might contribute to guide the adjustment and emphasis of adaptation policies and climate risk management strategies from local to national level. |
| Microbial Biogeochemical Cycling of Nitrogen in Arid Ecosystems | Microbiology and Molecular Biology Reviews | Ramond, J.; Jordaan, K.; Díez, B.; Heinzelmann, S.; Cowan, D. | 2022 | Zonas Costeras | 10.1128/mmbr.00109-21 | https://journals.asm.org/doi/10.1128/mmbr.00109-21 | e00109-21 | Vol: 86 Issue: 2 | 1092-2172, 1098-5557 | Thomson Reuters ISI (SCIE) | | English | Arid ecosystems cover ∼40% of the Earth’s terrestrial surface and store a high proportion of the global nitrogen (N) pool. They are low-productivity, low-biomass, and polyextreme ecosystems, i.e., with (hyper)arid and (hyper)oligotrophic conditions and high surface UV irradiation and evapotranspiration. These polyextreme conditions severely limit the presence of macrofauna and -flora and, particularly, the growth and productivity of plant species.
,
SUMMARY
Arid ecosystems cover ∼40% of the Earth’s terrestrial surface and store a high proportion of the global nitrogen (N) pool. They are low-productivity, low-biomass, and polyextreme ecosystems, i.e., with (hyper)arid and (hyper)oligotrophic conditions and high surface UV irradiation and evapotranspiration. These polyextreme conditions severely limit the presence of macrofauna and -flora and, particularly, the growth and productivity of plant species. Therefore, it is generally recognized that much of the primary production (including N-input processes) and nutrient biogeochemical cycling (particularly N cycling) in these ecosystems are microbially mediated. Consequently, we present a comprehensive survey of the current state of knowledge of biotic and abiotic N-cycling processes of edaphic (i.e., open soil, biological soil crust, or plant-associated rhizosphere and rhizosheath) and hypo/endolithic refuge niches from drylands in general, including hot, cold, and polar desert ecosystems. We particularly focused on the microbially mediated biological nitrogen fixation, N mineralization, assimilatory and dissimilatory nitrate reduction, and nitrification N-input processes and the denitrification and anaerobic ammonium oxidation (anammox) N-loss processes. We note that the application of modern meta-omics and related methods has generated comprehensive data sets on the abundance, diversity, and ecology of the different N-cycling microbial guilds. However, it is worth mentioning that microbial N-cycling data from important deserts (e.g., Sahara) and quantitative rate data on N transformation processes from various desert niches are lacking or sparse. Filling this knowledge gap is particularly important, as climate change models often lack data on microbial activity and environmental microbial N-cycling communities can be key actors of climate change by producing or consuming nitrous oxide (N
2
O), a potent greenhouse gas. |
| Isotopic Characterization of Water Masses in the Southeast Pacific Region: Paleoceanographic Implications | Journal of Geophysical Research: Oceans | Reyes‐Macaya, D.; Hoogakker, B.; Martínez‐Méndez, G.; Llanillo, P.; Grasse, P.; Mohtadi, M.; Mix, A.; Leng, M.; Struck, U.; McCorkle, D.; Troncoso, M.; Gayo, E.; Lange, C.; Farías, L.; Carhuapoma, W.; Graco, M.; Cornejo‐D’Ottone, M.; De Pol Holz, R.; Fernandez, C.; Narvaez, D.; Vargas, C.; García‐Ar... | 2022 | Zonas Costeras | 10.1029/2021JC017525 | https://onlinelibrary.wiley.com/doi/10.1029/2021JC017525 | art: e2021JC017525 | Vol: 127 Issue: 1 | 2169-9275, 2169-9291 | Thomson Reuters ISI (SCIE) | | English | In this study, we used stable isotopes of oxygen (δ18O), deuterium (δD), and dissolved inorganic carbon (δ13CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71°–78°W) and an oceanic (82°–98°W) water masses (SAAW—Subantarctic Surface Water; STW—Subtropical Water; ESSW—Equatorial Subsurface water; AAIW—Antarctic Intermediate Water; PDW—Pacific Deep Water) of the Southeast Pacific (SEP). The results show that δ18O and δD can be used to differentiate between SAAW-STW, SAAW-ESSW, and ESSW-AAIW. δ13CDIC signatures can be used to differentiate between STW-ESSW (oceanic section), SAAW-ESSW, ESSW-AAIW, and AAIW-PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1,000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present-day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples. © 2021. The Authors. |
| Recent Changes in the Low-Level Jet along the Subtropical West Coast of South America | Atmosphere | Aguirre, C.; Flores-Aqueveque, V.; Vilches, P.; Vásquez, A.; Rutllant, J.; Garreaud, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.3390/atmos12040465 | https://www.mdpi.com/2073-4433/12/4/465 | 465 | Vol: 12 Issue: 4 | 2073-4433 | Thomson Reuters ISI (SCIE) | | English | Surface winds along the subtropical west coast of South America are characterized by the quasi-weekly occurrences of low-level jet events. These short lived but intense wind events impact the coastal ocean environment. Hence, identifying long-term trends in the coastal low-level jet (CLLJ) is essential for understanding changes in marine ecosystems. Here we use ERA5 reanalysis (1979–2019) and an objective algorithm to track anticyclones to investigate recent changes in CLLJ events off central Chile (25–43 °S). Results present evidence that the number of days with intense wind (≥10 ms−1), and the number and duration of CLLJ events have significantly changed off central Chile in recent decades. There is an increase in the number of CLLJ events in the whole study area during winter (June-July-August; JJA), while during summer (December–January–February; DJF) a decrease is observed at lower latitudes (29–34 °S), and an increase is found at the southern boundary of the Humboldt system. We suggest that changes in the central pressures and frequency of extratropical, migratory anticyclones that reach the coast of South America, which force CLLJs, have played an important role in the recent CLLJ changes observed in this region. |
| High-Frequency Variability of the Surface Ocean Properties Off Central Chile During the Upwelling Season | Frontiers in Marine Science | Aguirre, C.; Garreaud, R.; Belmar, L.; Farías, L.; Ramajo, L.; Barrera, F. | 2021 | Agua y Extremos; Zonas Costeras | 10.3389/fmars.2021.702051 | https://www.frontiersin.org/articles/10.3389/fmars.2021.702051/full | 702051 | Vol: 8 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | The ocean off south-central Chile is subject to seasonal upwelling whose intensity is mainly controlled by the latitudinal migration of the southeast Pacific subtropical anticyclone. During austral spring and summer, the mean flow is equatorward favoring coastal upwelling, but periods of strong southerly winds are intermixed with periods of relaxed southerlies or weak northerly winds (downwelling favorable). This sub-seasonal, high-frequency variability of the coastal winds results in pronounced changes in oceanographic conditions and air-sea heat and gas exchanges, whose quantitative description has been limited by the lack of
in-situ
monitoring. In this study, high frequency fluctuations of meteorological, oceanographic and biogeochemical near surface variables were analyzed during two consecutive upwelling seasons (2016–17 and 2017–18) using observations from a coastal buoy located in the continental shelf off south-central Chile (36.4°S, 73°W), ∼10 km off the coast. The radiative-driven diel cycle is noticeable in meteorological variables but less pronounced for oceanographic and biogeochemical variables [ocean temperature, nitrate (NO
3
−), partial pressure of carbon dioxide (
p
CO
2
sea
), pH, dissolved oxygen (DO)]. Fluorescence, as a proxy of chlorophyll-
a
, showed diel variations more controlled by biological processes. In the synoptic scale, 23 active upwelling events (strong southerlies, lasting between 2 and 15 days, 6 days in average) were identified, alternated with periods of relaxed southerlies of shorter duration (4.5 days in average). Upwelling events were related to the development of an atmospheric low-level coastal jet in response to an intense along-shore pressure gradient. Physical and biogeochemical surface seawater properties responded to upwelling favorable wind stress with approximately a 12-h lag. During upwelling events, SST, DO and pH decrease, while NO
3
−,
p
CO
2
sea
, and air-sea fluxes increases. During the relaxed southerly wind periods, opposite tendencies were observed. The fluorescence response to wind variations is complex and diverse, but in many cases there was a reduction in the phytoplankton biomass during the upwelling events followed by higher values during wind relaxations. The sub-seasonal variability of the coastal ocean characterized here is important for biogeochemical and productivity studies. |
| Ecogenomics and Adaptation Strategies of Southern Ocean Viral Communities | mSystems | Alarcón-Schumacher, T.; Guajardo-Leiva, S.; Martinez-Garcia, M.; Díez, B. | 2021 | Zonas Costeras | 10.1128/mSystems.00396-21 | https://journals.asm.org/doi/10.1128/mSystems.00396-21 | e00396-21 | Vol: 6 Issue: 4 | 2379-5077 | Thomson Reuters ISI (SCIE) | | English | Viruses are the most abundant biologic entities in marine systems and strongly influence the microbial community composition and diversity. However, little is known about viral communities’ adaptation and diversification in the ocean.
,
ABSTRACT
The Southern Ocean (SO) represents up to one-fifth of the total carbon drawdown worldwide. Intense selective pressures (low temperature, high UV radiation, and strong seasonality) and physical isolation characterize the SO, serving as a “natural” laboratory for the study of ecogenomics and unique adaptations of endemic viral populations. Here, we report 2,416 novel viral genomes from the SO, obtained from newly sequenced viral metagenomes in combination with mining of publicly available data sets, which represents a 25% increase in the SO viral genomes reported to date. They comprised 567 viral clusters (defined as approximately genus-level groups), with 186 genera endemic to the SO, demonstrating that the SO viral community is predominantly constituted by a large pool of genetically divergent viral species from widespread viral families. The predicted proteome from SO viruses revealed that several protein clusters related to cold-shock-event responses and quorum-sensing mechanisms involved in the lysogenic-lytic cycle shift decision were under positive selection, which is ultimately important for fine adaptation of viral populations in response to the strong selective pressures of the SO. Finally, changes in the hydrophobicity patterns and amino acid frequencies suggested marked temperature-driven genetic selection of the SO viral proteome. Our data provide valuable insights into how viruses adapt and remain successful in this extreme polar marine environment.
IMPORTANCE
Viruses are the most abundant biologic entities in marine systems and strongly influence the microbial community composition and diversity. However, little is known about viral communities’ adaptation and diversification in the ocean. In this work, we take advantage of the geographical isolation and the intense selective pressures of the SO, to which viruses are exposed, to identify potential viral adaptations due to positive environmental selection and dispersal limitation. To that end, we recovered more than two thousand novel viral genomes, revealing a high degree of divergence in these SO endemic communities. Furthermore, we describe remarkable viral adaptations in amino acid frequencies and accessory proteins related to cold shock response and quorum sensing that allow them to thrive at lower temperatures. Consequently, our work greatly expands the understanding of the diversification of the viral communities of the SO and their particular adaptations to low temperatures. |
| Coastal Bacterial Community Response to Glacier Melting in the Western Antarctic Peninsula | Microorganisms | Alcamán-Arias, M.; Fuentes-Alburquenque, S.; Vergara-Barros, P.; Cifuentes-Anticevic, J.; Verdugo, J.; Polz, M.; Farías, L.; Pedrós-Alió, C.; Díez, B. | 2021 | Zonas Costeras | 10.3390/microorganisms9010088 | https://www.mdpi.com/2076-2607/9/1/88 | 88 | Vol: 9 Issue: 1 | 2076-2607 | Thomson Reuters ISI (SCIE) | | English | Current warming in the Western Antarctic Peninsula (WAP) has multiple effects on the marine ecosystem, modifying the trophic web and the nutrient regime. In this study, the effect of decreased surface salinity on the marine microbial community as a consequence of freshening from nearby glaciers was investigated in Chile Bay, Greenwich Island, WAP. In the summer of 2016, samples were collected from glacier ice and transects along the bay for 16S rRNA gene sequencing, while in situ dilution experiments were conducted and analyzed using 16S rRNA gene sequencing and metatranscriptomic analysis. The results reveal that certain common seawater genera, such as Polaribacter, Pseudoalteromonas and HTCC2207, responded positively to decreased salinity in both the bay transect and experiments. The relative abundance of these bacteria slightly decreased, but their functional activity was maintained and increased the over time in the dilution experiments. However, while ice bacteria, such as Flavobacterium and Polaromonas, tolerated the increased salinity after mixing with seawater, their gene expression decreased considerably. We suggest that these bacterial taxa could be defined as sentinels of freshening events in the Antarctic coastal system. Furthermore, these results suggest that a significant portion of the microbial community is resilient and can adapt to disturbances, such as freshening due to the warming effect of climate change in Antarctica. |
| Niche differentiation of Dinophysis acuta and D. acuminata in a stratified fjord | Harmful Algae | Baldrich, Á.; Pérez-Santos, I.; Álvarez, G.; Reguera, B.; Fernández-Pena, C.; Rodríguez-Villegas, C.; Araya, M.; Álvarez, F.; Barrera, F.; Karasiewicz, S.; Díaz, P. | 2021 | Zonas Costeras | 10.1016/j.hal.2021.102010 | https://linkinghub.elsevier.com/retrieve/pii/S1568988321000378 | 102010 | Vol: 103 | 15689883 | Thomson Reuters ISI (SCIE) | | English | Dinophysis acuta and D. acuminata are associated with lipophilic toxins in Southern Chile. Blooms of the two species coincided during summer 2019 in a highly stratified fjord system (Puyuhuapi, Chilean Patagonia). High vertical resolution measurements of physical parameters were carried out during 48 h sampling to i) explore physiological status (e.g., division rates, toxin content) and ii) illustrate the fine scale distribution of D. acuta and D. acuminata populations with a focus on water column structure and co-occurring plastid-bearing ciliates. The species-specific resources and regulators defining the realized niches (sensu Hutchinson) of the two species were identified. Differences in vertical distribution, daily vertical migration and in situ division rates (with record values, 0.76 d−1, in D. acuta), in response to the environmental conditions and potential prey availability, revealed their niche differences. The Outlying Mean Index (OMI) analysis showed that the realized niche of D. acuta (cell maximum 7 × 103 cells L−1 within the pycnocline) was characterized by sub-surface estuarine waters (salinity 23 – 25), lower values of turbulence and PAR, and a narrow niche breath. In contrast, the realized niche of D. acuminata (cell maximum 6.8 × 103 cells L−1 just above the pycnocline) was characterized by fresher (salinity 17 – 20) outflowing surface waters, with higher turbulence and light intensity and a wider niche breadth. Results from OMI and PERMANOVA analyses of co-occurring microplanktonic ciliates were compatible with the hypothesis of species such as those from genera Pseudotontonia and Strombidium constituting an alternative ciliate prey to Mesodinium. The D. acuta cell maximum was associated with DSP (OA and DTX-1) toxins and pectenotoxins; that of D. acuminata only with pectenotoxins. Results presented here contribute to a better understanding of the environmental drivers of species-specific blooms of Dinophysis and management of their distinct effects in Southern Chile. |
| Temperature and precipitation projections for the Antarctic Peninsula over the next two decades: contrasting global and regional climate model simulations | Climate Dynamics | Bozkurt, D.; Bromwich, D.; Carrasco, J.; Rondanelli, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.1007/s00382-021-05667-2 | http://link.springer.com/10.1007/s00382-021-05667-2 | 3853-3874 | Vol: 56 Issue: 11-12 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | | English | This study presents near future (2020–2044) temperature and precipitation changes over the Antarctic Peninsula under the high-emission scenario (RCP8.5). We make use of historical and projected simulations from 19 global climate models (GCMs) participating in Coupled Model Intercomparison Project phase 5 (CMIP5). We compare and contrast GCMs projections with two groups of regional climate model simulations (RCMs): (1) high resolution (15-km) simulations performed with Polar-WRF model forced with bias-corrected NCAR-CESM1 (NC-CORR) over the Antarctic Peninsula, (2) medium resolution (50-km) simulations of KNMI-RACMO21P forced with EC-EARTH (EC) obtained from the CORDEX-Antarctica. A further comparison of historical simulations (1981–2005) with respect to ERA5 reanalysis is also included for circulation patterns and near-surface temperature climatology. In general, both RCM boundary conditions represent well the main circulation patterns of the historical period. Nonetheless, there are important differences in projections such as a notable deepening and weakening of the Amundsen Sea Low in EC and NC-CORR, respectively. Mean annual near-surface temperatures are projected to increase by about 0.5–1.5 ∘C across the entire peninsula. Temperature increase is more substantial in autumn and winter (∼ 2 ∘C). Following opposite circulation pattern changes, both EC and NC-CORR exhibit different warming rates, indicating a possible continuation of natural decadal variability. Although generally showing similar temperature changes, RCM projections show less warming and a smaller increase in melt days in the Larsen Ice Shelf compared to their respective driving fields. Regarding precipitation, there is a broad agreement among the simulations, indicating an increase in mean annual precipitation (∼ 5 to 10%). However, RCMs show some notable differences over the Larsen Ice Shelf where total precipitation decreases (for RACMO) and shows a small increase in rain frequency. We conclude that it seems still difficult to get consistent projections from GCMs for the Antarctic Peninsula as depicted in both RCM boundary conditions. In addition, dominant and common changes from the boundary conditions are largely evident in the RCM simulations. We argue that added value of RCM projections is driven by processes shaped by finer local details and different physics schemes that are introduced by RCMs, particularly over the Larsen Ice Shelf. |
| Projected increases in surface melt and ice loss for the Northern and Southern Patagonian Icefields | Scientific Reports | Bravo, C.; Bozkurt, D.; Ross, A.; Quincey, D. | 2021 | Zonas Costeras | 10.1038/s41598-021-95725-w | https://www.nature.com/articles/s41598-021-95725-w | 16847 | Vol: 11 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | | English | The Northern Patagonian Icefield (NPI) and the Southern Patagonian Icefield (SPI) have increased their ice mass loss in recent decades. In view of the impacts of glacier shrinkage in Patagonia, an assessment of the potential future surface mass balance (SMB) of the icefields is critical. We seek to provide this assessment by modelling the SMB between 1976 and 2050 for both icefields, using regional climate model data (RegCM4.6) and a range of emission scenarios. For the NPI, reductions between 1.5 m w.e. (RCP2.6) and 1.9 m w.e. (RCP8.5) were estimated in the mean SMB during the period 2005–2050 compared to the historical period (1976–2005). For the SPI, the estimated reductions were between 1.1 m w.e. (RCP2.6) and 1.5 m w.e. (RCP8.5). Recently frontal ablation estimates suggest that mean SMB in the SPI is positively biased by 1.5 m w.e., probably due to accumulation overestimation. If it is assumed that frontal ablation rates of the recent past will continue, ice loss and sea-level rise contribution will increase. The trend towards lower SMB is mostly explained by an increase in surface melt. Positive ice loss feedbacks linked to increasing in meltwater availability are expected for calving glaciers. |
| Escuelas Seguras en tiempos del COVID-19 | | Brevis, W.; Cortés, S.; Duarte, I.; Fica, D.; Förster, F.; Martínez, S.; Rojas, M.; Repetto, P.; Rondanelli, R.; Valdés, M. | 2021 | Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://portaluchile.uchile.cl/documentos/escuelas-seguras-en-tiempos-del-covid-19_176441_0_4940.pdf | | | | | | | v1.3 |
| A review of the observed air temperature in the Antarctic Peninsula. Did the warming trend come back after the early 21st hiatus? | Polar Science | Carrasco, J.; Bozkurt, D.; Cordero, R. | 2021 | Zonas Costeras | 10.1016/j.polar.2021.100653 | https://linkinghub.elsevier.com/retrieve/pii/S1873965221000189 | 100653 | Vol: 28 | 18739652 | Thomson Reuters ISI (SCIE) | | English | Recent changes in the near-surface air temperature (nSAT) in the Antarctic Peninsula (AP) suggests that the absence of 21st century warming on Antarctic Peninsula may be coming to end. To examine this, the long-term annual and seasonal variability of the nSAT at eight Antarctic stations located in the AP are analyzed using available data from the SCAR Reader database, complemented with data from the Chilean Weather Service (Frei and O’Higgins). An exponential lter was applied to the original annual and seasonal mean series to obtain a decadal-like variation of the nSAT. A stacked and the standardized anomaly of the nSAT record was constructed to examine the average regional behavior in the AP. Cumulative sum (CUSUM) and changepoint analysis were applied through the stacked nSAT series to highlight signi cant changes caused by variation in weather and climate. The CUSUM and bootstrapping analysis revealed two statistically signi cant breaking points during the 1978–2020 period. The rst one occurred in the late nineties ending a warming period and making the beginning of a cooling period; the second one may have taken place in the mid-2010s and could mark the end of the warming pause. These trends appear to be consistent with the changes observed in the large-scale climate modes (i.e., the Antarctic Annular Mode – AAO). |
| Dissolved nitrous oxide distribution in the central South Pacific | | Charpentier, J.; Farías, L.; Pizarro, O. | 2021 | Zonas Costeras | 10.1594/PANGAEA.928664 | https://doi.pangaea.de/10.1594/PANGAEA.928664 | | | | Pangaea | | English | Nitrous oxide (N2O) is an important atmospheric trace gas involved in tropospheric warming and stratospheric ozone depletion. The ocean is a net source of this gas, contributing around 25% of global N2O sources, although this emission is highly variable. It is the case of eastern South Pacific, a region with marked zonal gradients, ranging from highly productive and suboxic conditions in coastal upwelling systems to oligotrophic and oxygenated conditions in the subtropical gyre. Indeed, South Pacific Ocean has the largest permanent anticyclonic oceanic gyre which has been described as the most oligotrophic zone in the world ocean. Nitrous oxide concentration in the water column was measured on a transect crossing the Subtropical South Pacific Gyre during the BIOSOPE cruise (austral spring, 2004). This dataset includes nitrous oxide and nutrient concentrations at different depths from French program BIOSOPE, funded by the Centre National de la Recherche Scientifique (CNRS), the Institut des Sciences de l'Univers (INSU), the Centre National d'Etudes Spatiales (CNES), the European Space Agency (ESA), The National Aeronautics and Space Administration (NASA) and the Natural Sciences and Engineering Research Council of Canada (NSERC). Nitrous oxide measurements belong to Concepción University. |
| Proteorhodopsin Phototrophy in Antarctic Coastal Waters | mSphere | Cifuentes-Anticevic, J.; Alcamán-Arias, M.; Alarcón-Schumacher, T.; Tamayo-Leiva, J.; Pedrós-Alió, C.; Farías, L.; Díez, B. | 2021 | Zonas Costeras | 10.1128/mSphere.00525-21 | https://journals.asm.org/doi/10.1128/mSphere.00525-21 | 1-17 | Vol: 6 Issue: 4 | 2379-5042 | Thomson Reuters ISI (SCIE) | | English | Proteorhodopsin-bearing microorganisms in the Southern Ocean have been overlooked since their discovery in 2000. The present study identify taxonomy and quantify the relative abundance of proteorhodopsin-bearing bacteria and proteorhodopsin gene transcription in the West Antarctic Peninsula’s coastal waters.
,
ABSTRACT
Microbial proton-pumping rhodopsins are considered the simplest strategy among phototrophs to conserve energy from light. Proteorhodopsins are the most studied rhodopsins thus far because of their ubiquitous presence in the ocean, except in Antarctica, where they remain understudied. We analyzed proteorhodopsin abundance and transcriptional activity in the Western Antarctic coastal seawaters. Combining quantitative PCR (qPCR) and metagenomics, the relative abundance of proteorhodopsin-bearing bacteria accounted on average for 17, 3.5, and 29.7% of the bacterial community in Chile Bay (South Shetland Islands) during 2014, 2016, and 2017 summer-autumn, respectively. The abundance of proteorhodopsin-bearing bacteria changed in relation to environmental conditions such as chlorophyll
a
and temperature.
Alphaproteobacteria
,
Gammaproteobacteria
, and
Flavobacteriia
were the main bacteria that transcribed the proteorhodopsin gene during day and night. Although green light-absorbing proteorhodopsin genes were more abundant than blue-absorbing ones, the latter were transcribed more intensely, resulting in >50% of the proteorhodopsin transcripts during the day and night.
Flavobacteriia
were the most abundant proteorhodopsin-bearing bacteria in the metagenomes; however,
Alphaproteobacteria
and
Gammaproteobacteria
were more represented in the metatranscriptomes, with qPCR quantification suggesting the dominance of the active SAR11 clade. Our results show that proteorhodopsin-bearing bacteria are prevalent in Antarctic coastal waters in late austral summer and early autumn, and their ecological relevance needs to be elucidated to better understand how sunlight energy is used in this marine ecosystem.
IMPORTANCE
Proteorhodopsin-bearing microorganisms in the Southern Ocean have been overlooked since their discovery in 2000. The present study identify taxonomy and quantify the relative abundance of proteorhodopsin-bearing bacteria and proteorhodopsin gene transcription in the West Antarctic Peninsula’s coastal waters. This information is crucial to understand better how sunlight enters this marine environment through alternative ways unrelated to chlorophyll-based strategies. The relative abundance of proteorhodopsin-bearing bacteria seems to be related to environmental parameters (e.g., chlorophyll
a
, temperature) that change yearly at the coastal water of the West Antarctic Peninsula during the austral late summers and early autumns. Proteorhodopsin-bearing bacteria from Antarctic coastal waters are potentially able to exploit both the green and blue spectrum of sunlight and are a prevalent group during the summer in this polar environment. |
| Electrochemical enrichment of marine denitrifying bacteria to enhance nitrate metabolization in seawater | Journal of Environmental Chemical Engineering | De La Fuente, M.; De la Iglesia, R.; Farías, L.; Daims, H.; Lukumbuzya, M.; Vargas, I. | 2021 | Zonas Costeras | 10.1016/j.jece.2021.105604 | https://linkinghub.elsevier.com/retrieve/pii/S2213343721005819 | 105604 | Vol: 9 Issue: 4 | 2213-3437 | Thomson Reuters ISI (SCIE) | | English | High concentrations of nitrate from industrial discharges to coastal marine environments are a matter of concern owing to their ecological consequences. In the last years, Bioelectrochemical Denitrification Systems (BEDS) have emerged as a promising nitrate removal technology. However, they still have limitations, such as the enrichment strategy for specific microbial communities in the electrodes under natural conditions. In this study, three-electrode electrochemical cells were used to test microbial enrichment from natural seawater by applying three reported potentials associated with the dissimilatory denitrification process (−130, −260, and −570 mV vs. Ag/AgCl). The microbial community analysis showed that by applying −260 mV (vs. Ag/AgCl) to the working electrode, it was possible to significantly enrich denitrifying microorganisms, specifically Marinobacter, in comparison with the control. Furthermore, −260 mV (vs. Ag/AgCl) led to a significantly higher nitrate removal than other conditions, which, combined with cyclic voltammetry analysis, suggested that the polarized electrodes worked as external electron donors for nitrate reduction. Hence, this work demonstrates for the first time that it is possible to enrich marine denitrifying microorganisms by applying an overpotential of −260 mV (vs. Ag/AgCl) without the need for a culture medium, the addition of an exogenous electron donor (i.e., organic matter) or a previously enriched inoculum. |
| Identifying key driving mechanisms of heat waves in central Chile | Climate Dynamics | Demortier, A.; Bozkurt, D.; Jacques-Coper, M. | 2021 | Agua y Extremos; Zonas Costeras | 10.1007/s00382-021-05810-z | https://link.springer.com/10.1007/s00382-021-05810-z | 2415-2432 | Vol: 57 Issue: 9-10 | 0930-7575, 1432-0894 | Thomson Reuters ISI (SCIE) | | English | This study explores the main drivers of heat wave (HW) events in central Chile using state-of-the-art reanalysis data (ERA5) and observations during the extended austral summer season (November to March) for the period 1979–2018. Frequency and intensity aspects of the HW events are considered using the total number of the HW events per season and the amplitude. We first contrast ERA5 with several surface meteorological stations in central Chile to evaluate its ability to capture daily maximum temperature variability and the HW events. We then use synoptic- and large-scale fields and teleconnection patterns to address the most favorable conditions of the HW events from a climatological perspective as well as from the extreme January 2017 HW event that swept central Chile with temperature records and wildfires. ERA5 tends to capture temperature extremes and the HW events at the inland stations; on the contrary, it has difficulties in capturing the maximum temperature variability at the coastal stations, which is plausible given the complex terrain features and confined coastal climate zone (only ∼ 7% of all grid boxes within central Chile). The composite HW days based on ERA5 reveals a mid-level trough-ridge dipole pattern exhibiting a blocking anticyclone on the surface over a large part of southwest South America. Relatively dry and warm easterly flow appears to accompany the anomalous warming in a large part of central Chile. The temporal evolution of the HW events yields a wave-like propagation pattern and enhancement of trough-ridge pattern along the South Pacific. This meridional dipole pattern is found to be largely associated with the Pacific South American pattern. In addition, the Madden–Julian Oscillation (MJO) appears to be a key component of the HW events in central Chile. In particular, while active MJO phases 2 and 7 promote sub-seasonal patterns that favor the South Pacific dipole mode, synoptic anomalies can superimpose on them and favor the formation of a migrating anticyclone over central-southern Chile and coastal lows over central Chile. Agreeing with the climatological findings, the extreme January 2017 HW analysis suggests that an eastward migratory mid-latitude trough-ridge pattern associated with MJO phase 2 was at work. We highlight that in addition to large- and synoptic-scale features, sub-synoptic processes such as coastal lows can have an important role in shaping the HW events and can lead to amplification of temperature extremes during the HW events. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. |
| Más de 20 años de monitoreo del sistema de surgencia costera de Chile central | Universidad de Concepción | Farías, L.; Manríquez, V.; De la Maza, L. | 2021 | Zonas Costeras | 10.48665/udec/CMHMEQ | https://www.researchgate.net/publication/355484145_Mas_de_20_anos_de_monitoreo_del_sistema_de_surgencia_costera_de_Chile_central_final | | | | | | | El océano actúa como el regulador del estado medio climático en el planeta Tierra, absorbiendo calor, controlando la concentración de gases de efecto invernadero en la atmósfera
y manteniendo el ciclo hidrológico que suministra agua dulce al planeta. El monitoreo del océano es necesario para comprender su dinámica a diferentes escalas temporales y espaciales, así como para cuantificar el impacto de los procesos globales como el cambio climático (CC) en su funcionamiento. El monitoreo permite finalmente dimensionar impactos y evaluar la vulnerabilidad de sus ecosistemas y comunidades costeras. Los humanos dependen del océano, debido a los múltiples servicios ecosistémicos que este entrega, i.e., pesca, acuicultura, provisión de productos naturales, purificación/desalinización de agua, protección de la costa, transporte y recreación/turismo, entre algunos. Este es el caso de Chile, un país con vocación oceánica altamente vulnerable al CC, pero con escaso monitoreo de océano y, por lo tanto, con limitada capacidad para estimar la intensidad de las amenazas, y para predecir impactos, herramienta esencial para adaptarse al CC y otros fenómenos. |
| Temporal methane variability in the water column of an area of seasonal coastal upwelling: A study based on a 12 year time series | Progress in Oceanography | Farías, L.; Tenorio, S.; Sanzana, K.; Faundez, J. | 2021 | Zonas Costeras | 10.1016/j.pocean.2021.102589 | https://linkinghub.elsevier.com/retrieve/pii/S0079661121000768 | 102589 | Vol: 195 | 0079-6611 | Thomson Reuters ISI (SCIE) | | English | Temporal distribution of dissolved CH4 was analysed in a zone of strong seasonal coastal upwelling off central Chile (36.5°S,73°W). Observations were taken from a twelve-year time series that included monthly sampling of the water at eight depths. CH4 concentration fluctuated between 1.75 and 100.9 nmol L-1 (or 67.11% and 3965% of saturation), with the highest levels at bottom waters, which increase as upwelling evolved. Three kind of CH4 profiles were identified; a classical diffusion–advection distribution, with bottom/surface CH4 concentration ratio > 2, was predominantly observed in ~ 54% of the all profiles and attributed to high CH4 production in the sediments during coastal upwelling season (austral spring-summer); a period of higher biological productivity, as well as in hypoxic/anoxic condition. In contrast, relatively homogeneous profiles (CH4 level ratio between bottom and surface depth < 2) was observed about ~ 46% of all profiles during periods of extreme vertical mixing (such as winter storms). Furthermore, irregular CH4 profile with superficial peaks occurring between the surface and 15–30 m depth was likely observed. These peaks indicated that local production rates exceed turbulent mixing rates, suggesting a rapid CH4 cycling due to microbial processes on the surface. Despite the fact that strong seasonality was observed in most oceanographic variables, according to favourable and non-favourable upwelling periods, only a weak seasonality was observed in CH4 content and its air-sea flux, the latter ranged from 1.27 to 47.02 µmol m−2 d-1 (mean ± SD: 10.94 ± 7.48). The annual weighted mean CH4 effluxes during upwelling (64%) and non-upwelling (36%) periods fluctuated from 1.66 to 6.22 mmol m−2 (mean ± SD: 3.40 ± 1.43), highlighting the importance of the continental shelf under the influence of coastal upwelling as a significant CH4 source toward the atmosphere. © 2021 |
| Spatial Distribution of Dissolved Methane Over Extreme Oceanographic Gradients in the Subtropical Eastern South Pacific (17° to 37°S) | Journal of Geophysical Research: Oceans | Farías, L.; Troncoso, M.; Sanzana, K.; Verdugo, J.; Masotti, I. | 2021 | Zonas Costeras | 10.1029/2020JC016925 | https://onlinelibrary.wiley.com/doi/10.1029/2020JC016925 | art: e2020JC016925 | Vol: 126 Issue: 5 | 2169-9275, 2169-9291 | Thomson Reuters ISI (SCIE) | | English | Methane (CH4) is one of the most powerful greenhouse gases with the capacity to influence the Earth's radiative budget as well as contribute to atmospheric chemistry. Natural oceanic production makes up to ∼4% of the overall global CH4 emissions, however, there is uncertainty around the accuracy of this value due to a lack of accurate measurements. Such is the case in the Subtropical Eastern South Pacific Ocean (SESP), a region with pronounced chlorophyll-a and oxygen gradients, which in turn affect the microbial CH4 cycling. This study was conducted during spring-summer (2014–2016) in the SESP. The region (∼17°–37°S/71°–110°W) is separated into (i) eutrophic, (ii) mesotrophic, and (iii) oligotrophic areas, according to oceanographic and biogeochemical criteria. The SESP presents high CH4 zonal variability with levels ranging from 0.63 to 33.4 nmol L−1, corresponding to 29% and 1,423% saturation, respectively. High CH4 concentrations (>1,000% saturation) are observed in the narrow eutrophic area subjected to coastal upwelling. These conditions clearly differ to those observed in the extended oligotrophic subtropical gyre (∼100% saturation). Furthermore, CH4 also tends to accumulate in the mesotrophic area (with upto 1,423% saturation), where oceanographic conditions as stratification, mesoscale eddies and island mass effect could trigger the presence of a microbial biomass that may be able to induce CH4 regeneration. The CH4 efflux is estimated to be between 0.13 and 19.1 µmol m−2 d−1 (mean ± SD = 4.72 ± 4.67) and the SESP has an emission rate of ∼87.9 Gg CH4 yr−1. |
| Extreme zonal and vertical gradients of nutrients and greenhouse gases in the subtropical Eastern South Pacific basin | | Farías, Laura; Troncoso, Macarena | 2021 | Zonas Costeras | 10.1594/PANGAEA.933734 | https://doi.pangaea.de/10.1594/PANGAEA.933734 | | | | Pangaea | | English | Between October 12 and November 5, 2015, the Cimar 21 “Ocean Islands” cruise was developed, organized and managed by the Navy's Hydrographic and Oceanographic Service (SHOA). This cruise covered the zonal transect in the subtropical region of the Eastern South Pacific Basin from Caldera (27.00°S; 70.88°W) to near Rapa Nui Island (27.04°S; 109.31°W). This region is characterized by presenting very contrasting trophic systems; from the coastal zone with eutrophic (rich in nutrients), colder and suboxic ([O2] <22 µM); to ultra-oligotrophic (with undetectable nutrient levels Raimbault et al., 2008), warmer and oxygenated waters that belong to South Pacific Subtropical Gyre, which has the clearest waters of the global ocean (Morel et al., 2010). In addition to trophic gradient, the Eastern South Pacific region presents an oxygen minimum zone (OMZ (Fuenzalida et al, 2009) with marked oxygen gradients where various biogeochemical processes can recycle greenhouse gases such as nitrous oxide (N2O) (Trocoso et al., 2018) and even methane (CH4) (Farías et al., 2021). From a total of 19 stations sampled, we present a set of data collected between 0 and 500 m depth using a CTD rosette for physicochemical variables such as temperature, salinity and oxygen (obtained from the CTD) and nutrients (nitrite, nitrate, phosphate, silicate) and greenhouse gases N2O and CH4 (obtained from Niskin bottles mounted in an oceanographic rosette). The gas samples were analyzed by gas chromatography through a gas chromatograph (Schimadzu 17A) using an electron capture detector at 350ºC and connected to an autoanalyzer, while the CH4 samples were analyzed manually in a chromatograph gas with flame ionization detector (Agilent Model 6850 GC-Fid) with a Restek RT QS-Bond column (30 meters 053 mm ID, 20 μm Film) with a temperature of 40ºC and a column flow of 4mL min-1. Meanwhile, nutrient samples with micromolar concentration (≥ 1 µM) were analyzed using standard colorimetric techniques (Grasshoff et al., 1983) in a Seal AA3 segmented flow auto-analyzer, whereas when the nutrient concentration was submicromolar (< 1 µM) for samples of nitrite, nitrate, and phosphate in the gyre, the Seal AA3 segmented flow autoanalyzer was used coupled to two 50 cm Liquid waveridge capillary cells (LWCC, Type II), which allowed to increase the sensitivity of the detection spectrophotometric (Troncoso et al., 2018). |
| He Antropoceno i a Tire: he mata ꞌite he haka pūai | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayó, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez, S.; Arriagada, R. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://bit.ly/3sAJOdv | | | | | | | Centro de Ciencia del Clima y la Resiliencia mew (CR)2, ta
iñ kvzawkan mew zujiyiñ fey ta nvxamkagelu Anxopozeno
zugu mew ta iñ inarumeael ka ta iñ gvnezuamael. Femgeci
ta cijkatuyiñ cumgeci cambio climático vñfitumapukey
kiñeke mapu mew Cile mew fanten mew, ta iñ kejuael
zugu mew cew ta cijkatugekey ka gvnezuamgekey weke
rvpv ta iñ kvme wimturpuael zugu mew mvlelu fanten
mew. Wvnelu ta inarumeyiñ ta pu registro geohistórico
pegeltulu cumgeci ta wizvmapukunurpukefuy kuyfi
mew ta cegen mapu mew Cile pigelu faciantv; fey mew
kvmeafuy wiñokintuliyiñ feyti mew kuyfi mew rupalu
ka kejuafulu sistemas socio-ecológicos zugu mew ta
kvpaialu. |
| Anxopozeno Cile mew: Ta iñ inazuamfiel ka cumgeci amulerpuael | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayó, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez, S.; Arriagada, R. | 2021 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://bit.ly/3FyHHL0 | | | | | | | Centro de Ciencia del Clima y la Resiliencia mew (CR)2, ta
iñ kvzawkan mew zujiyiñ fey ta nvxamkagelu Anxopozeno
zugu mew ta iñ inarumeael ka ta iñ gvnezuamael. Femgeci
ta cijkatuyiñ cumgeci cambio climático vñfitumapukey
kiñeke mapu mew Cile mew fanten mew, ta iñ kejuael
zugu mew cew ta cijkatugekey ka gvnezuamgekey weke
rvpv ta iñ kvme wimturpuael zugu mew mvlelu fanten
mew. Wvnelu ta inarumeyiñ ta pu registro geohistórico
pegeltulu cumgeci ta wizvmapukunurpukefuy kuyfi
mew ta cegen mapu mew Cile pigelu faciantv; fey mew
kvmeafuy wiñokintuliyiñ feyti mew kuyfi mew rupalu
ka kejuafulu sistemas socio-ecológicos zugu mew ta
kvpaialu. |
| Automated Low-Cost LED-Based Sun Photometer for City Scale Distributed Measurements | Remote Sensing | Garrido, C.; Toledo, F.; Diaz, M.; Rondanelli, R. | 2021 | Zonas Costeras | 10.3390/rs13224585 | https://www.mdpi.com/2072-4292/13/22/4585 | 4585 | Vol: 13 Issue: 22 | 2072-4292 | Thomson Reuters ISI (SCIE) | | English | We propose a monochromatic low-cost automatic sun photometer (LoCo-ASP) to perform distributed aerosol optical depth (AOD) measurements at the city scale. This kind of network could fill the gap between current automatic ground instruments—with good temporal resolution and accuracy, but few devices per city and satellite products—with global coverage, but lower temporal resolution and accuracy-. As a first approach, we consider a single equivalent wavelength around 408 nm. The cost of materials for the instrument is around 220 dollars. Moreover, we propose a calibration transfer for a pattern instrument, and estimate the uncertainties for several units and due to the internal differences and the calibration process. We achieve a max MAE of 0.026 for 38 sensors at 408 nm compared with AERONET Cimel; a mean standard deviation of 0.0062 among our entire sensor for measurement and a calibration uncertainty of 0.01. Finally, we perform city-scale measurements to show the dynamics of AOD. Our instrument can measure unsupervised, with an expected error for AOD between 0.02 and 0.03. |
| Seasonal precipitation in South Central Chile: trends in extreme events since 1900 | Atmósfera | González-Reyes, Á.; Jacques-Coper, M.; Muñoz, A. | 2021 | Agua y Extremos; Zonas Costeras | 10.20937/ATM.52871 | https://www.revistascca.unam.mx/atm/index.php/atm/article/view/52871 | 371-384 | Vol: 34 Issue: 4 | | Thomson Reuters ISI (SCIE) | | English | We study a regional precipitation time series, built upon seven meteorological records from South Central Chile (SCC; 37° - 42°S), which together cover the period 1900 - 2019. As a first objective, we investigated changes in the return period (RP) of dry ( P80) seasonal extreme events of precipitation (SEE), for each season. We observed a reduction in the RP of wet SEE during 1900 - 1950 in all seasons. Contrarily, the dry SEE RP shows a reduction from 1950 to the present in all seasons. This phenomenon is noteworthy since 1900 for summer and winter, and since 1930 for autumn. Spring registers a constant RP value from 1990 onwards. As a second objective, we study possible relationships between seasonal precipitation variability and climate modes, such as the Southern Annular Mode (SAM) and the Tripolar Index (TPI) of sea surface temperature (SST) over the Pacific Ocean. Summer and autumn precipitation register a significant negative correlation with SAM activity at interannual and decadal scales, while winter and spring precipitation show a significant positive correlation with SST variability over multiple regions of the Pacific Ocean (including the tropics and New Zealand) and the Southern Ocean (Amundsen-Bellingshausen Sea). Finally, we confirm that SAM strongly modulates precipitation in SCC, especially in autumn, and that SEE variability in SCC is considerably characterized by climate modes of tropical and extra-tropical origin. |
| Unveiling Ecological and Genetic Novelty within Lytic and Lysogenic Viral Communities of Hot Spring Phototrophic Microbial Mats | Microbiology Spectrum | Guajardo-Leiva, S.; Santos, F.; Salgado, O.; Regeard, C.; Quillet, L.; Díez, B. | 2021 | Zonas Costeras | 10.1128/Spectrum.00694-21 | https://journals.asm.org/doi/abs/10.1128/Spectrum.00694-21 | arte00694-21 | Vol: 9 Issue: 3 | 2165-0497 | Thomson Reuters ISI (SCIE) | | English | Hot springs harbor microbial communities dominated by a limited variety of microorganisms
and, as such, have become a model for studying community ecology and understanding
how biotic and abiotic interactions shape their structure. Viruses in hot springs
... |
| Intraseasonal teleconnections leading to heat waves in central Chile | International Journal of Climatology | Jacques‐Coper, M.; Veloso‐Aguila, D.; Segura, C.; Valencia, A. | 2021 | Zonas Costeras | 10.1002/joc.7096 | https://onlinelibrary.wiley.com/doi/10.1002/joc.7096 | 4712-4731 | Vol: 41 Issue: 9 | 0899-8418, 1097-0088 | Thomson Reuters ISI (SCIE) | | English | The ability to anticipate meteorological extreme events beyond the synoptic range of ~1 week offers direct applications, for example, to limit their ecological and socioeconomical impacts. This study focuses on precursors of summer (December–February, DJF) warm events, particularly heat waves, in central Chile (CCh), which are typically induced by low-level anticyclonic anomalies located to the south of this region. Considering that such atmospheric configuration can be part of a large-scale wave-train circulation pattern located upstream of CCh, we investigate signals that might provide guidance concerning the genesis of warm events in CCh. For a historical period (DJF 1872–2010) based on the 20th century reanalysis version 2 (20CR), our results present teleconnections that indicate higher probabilities of occurrence of such warm events with respect to expected climatological values. These signals can be monitored at least ~2 weeks in advance. Specifically, we explore the relationship between warm events in CCh and (a) the Madden-Julian Oscillation (MJO) as a tropical source of variability, and (b) an extra-tropical index (ETI), representative of the internal dynamics of the Southern Hemipshere mid-latitudes, presented as an original contribution from this study following a novel approach. Both signals, and apparently their constructive superposition, seem to contribute to the organization of the large-scale circulation anomalies leading ultimately to heat waves in CCh. We confirm these results for recent decades (DJF 1981–2020) using temperature observations and further data sets, namely the NCEP-NCAR Reanalysis (NNR) and the Climate Forecast System Reanalysis versions 1 and 2 (CFSR and CFSv2, respectively). Finally, we describe three recent heat wave events in CCh (DJF 2019–2020) to illustrate the suitability of this conceptualization. © 2021 Royal Meteorological Society |
| Contaminant emissions as indicators of chemical elements in the snow along a latitudinal gradient in southern Andes | Scientific Reports | Pizarro, J.; Vergara, P.; Cerda, S.; Cordero, R.; Castillo, X.; Rowe, P.; Casassa, G.; Carrasco, J.; Damiani, A.; Llanillo, P.; Lambert, F.; Rondanelli, R.; Huneeus, N.; Fernandoy, F.; Alfonso, J.; Neshyba, S. | 2021 | Zonas Costeras | 10.1038/s41598-021-93895-1 | http://www.nature.com/articles/s41598-021-93895-1 | 14530 | Vol: 11 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | | English | The chemical composition of snow provides insights on atmospheric transport of anthropogenic contaminants at different spatial scales. In this study, we assess how human activities influence the concentration of elements in the Andean mountain snow along a latitudinal transect throughout Chile. The concentration of seven elements (Al, Cu, Fe, Li, Mg, Mn and Zn) was associated to gaseous and particulate contaminants emitted at different spatial scales. Our results indicate carbon monoxide (CO) averaged at 20 km and nitrogen oxide (NOx) at 40 km as the main indicators of the chemical elements analyzed. CO was found to be a significant predictor of most element concentrations while concentrations of Cu, Mn, Mg and Zn were positively associated to emissions of NOx. Emission of 2.5 μm and 10 μm particulate matter averaged at different spatial scales was positively associated to concentration of Li. Finally, the concentration of Zn was positively associated to volatile organic compounds (VOC) averaged at 40 km around sampling sites. The association between air contaminants and chemical composition of snow suggests that regions with intensive anthropogenic pollution face reduced quality of freshwater originated from glacier and snow melting. |
| Drivers of dinoflagellate benthic cyst assemblages in the NW Patagonian Fjords System and its adjacent oceanic shelf, with a focus on harmful species | Science of The Total Environment | Rodríguez-Villegas, C.; Lee, M.; Salgado, P.; Figueroa, R.; Baldrich, Á.; Pérez-Santos, I.; Tomasetti, S.; Niklitschek, E.; Díaz, M.; Álvarez, G.; Marín, S.; Seguel, M.; Farías, L.; Díaz, P. | 2021 | Zonas Costeras | 10.1016/j.scitotenv.2021.147378 | https://linkinghub.elsevier.com/retrieve/pii/S0048969721024499 | 147378 | Vol: 785 | 0048-9697 | Thomson Reuters ISI (SCIE) | | English | In recent decades, the alteration of coastal food webs (via aquaculture, fishing, and leisure activities), nutrient loading, and an expansion of monitoring programs have prompted an apparent worldwide rise in Harmful Algae Blooms (HABs). Over this time, a parallel increase in HABs has also been observed in the Chilean southern austral region (Patagonia fjords). HAB species like Alexandrium catenella—responsible for Paralytic Shellfish Poisoning (PSP)—are of great public concern due to their negative socioeconomic impacts and significant northward geographical range expansion. Many toxic dinoflagellate species (like A. catenella) produce benthic resting cysts, yet a holistic understanding of the physical-chemical and biological conditions influencing the distributions of cysts in this region is lacking. In this study, we measured a combination of hydrographic (temperature, salinity, and dissolved oxygen) and sediment physical-chemical properties (temperature, pH and redox potential), in addition to meiofaunal abundances –as sediment bioturbators and potential cyst predators– to determine the factors influencing dinoflagellate cyst distribution, with emphasis on A. catenella in and around a “hotspot” area of southern Chile. An analysis of similarities (ANOSIM) test revealed significant differences (p < 0.011) in cyst assemblages between the fjords and oceanic environments. Permutational Analysis of Variance (PERMANOVA) showed significant effects of sediment temperature and silt proportion in explaining differences in the cyst assemblages. A generalized linear model (GLM) indicated that sediment temperature, silt/sand, anoxic conditions, and low abundances of Harpacticoida —a meiofauna herbivore group and potential bioturbator— are associated with the higher resting cyst abundances of the harmful species A. catenella. The implications for A. catenella resting cysts dynamics are discussed, highlighting physical-chemical and biological interactions and their potential for PSP outbreak initiation. |
| Comité Científico de Cambio Climático: Informe previo de la Estrategia Climática de Largo Plazo | | Rojas, M.; Farías, L.; González, H.; Marquet, P.; Muñoz, J.; Palma, R.; Stehr, A.; Vicuña, S. | 2021 | Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://comitecientifico.minciencia.gob.cl/wp-content/uploads/2021/11/Informe_Previo_ECLP_07.pdf | | | | | | | |
| The 21st-century fate of the Mocho-Choshuenco ice cap in southern Chile | The Cryosphere | Scheiter, M.; Schaefer, M.; Flández, E.; Bozkurt, D.; Greve, R. | 2021 | Agua y Extremos; Zonas Costeras | 10.5194/tc-15-3637-2021 | https://tc.copernicus.org/articles/15/3637/2021/ | 3637-3654 | Vol: 15 Issue: 8 | 1994-0424 | Thomson Reuters ISI (SCIE) | | English | Glaciers and ice caps are thinning and retreating along the entire Andes ridge, and drivers of this mass loss vary between the different climate zones. The southern part of the Andes (Wet Andes) has the highest abundance of glaciers in number and size, and a proper understanding of ice dynamics is important to assess their evolution. In this contribution, we apply the ice-sheet model SICOPOLIS (SImulation COde for POLythermal Ice Sheets) to the Mocho-Choshuenco ice cap in the Chilean Lake District (40∘ S, 72∘ W; Wet Andes) to reproduce its current state and to project its evolution until the end of the 21st century under different global warming scenarios. First, we create a model spin-up using observed surface mass balance data on the south-eastern catchment, extrapolating them to the whole ice cap using an aspect-dependent parameterization. This spin-up is able to reproduce the most important present-day glacier features. Based on the spin-up, we then run the model 80 years into the future, forced by projected surface temperature anomalies from different global climate models under different radiative pathway scenarios to obtain estimates of the ice cap's state by the end of the 21st century. The mean projected ice volume losses are 56±16 % (RCP2.6), 81±6 % (RCP4.5), and 97±2 % (RCP8.5) with respect to the ice volume estimated by radio-echo sounding data from 2013. We estimate the uncertainty of our projections based on the spread of the results when forcing with different global climate models and on the uncertainty associated with the variation of the equilibrium line altitude with temperature change. Considering our results, we project a considerable deglaciation of the Chilean Lake District by the end of the 21st century. |
| Trace elements in Antarctic penguins and the potential role of guano as source of recycled metals in the Southern Ocean | Chemosphere | Sparaventi, E.; Rodríguez-Romero, A.; Barbosa, A.; Ramajo, L.; Tovar-Sánchez, A. | 2021 | Zonas Costeras | 10.1016/j.chemosphere.2021.131423 | https://linkinghub.elsevier.com/retrieve/pii/S0045653521018956 | 131423 | Vol: 285 | 00456535 | Thomson Reuters ISI (SCIE) | | English | Penguins dominate the Antarctic avifauna. As key animals in the Antarctic ecosystem, they are monitored to evaluate the ecological status of this pristine and remote region and specifically, they have been used as effective bioindicators suitable for long-term monitoring of metals in the Antarctic environment. However, studies about the role of this emblematic organism could play in the recycling of trace metals (TMs) in the Antarctic ecosystem are very limited. In this study we evaluate, using the peer review research articles already published and our own findings, the distribution of metals (i.e., Ca, Fe, Al, Na, Zn, Mg, Cu, K, Cd, Mn, Sr, Cr, Ni, Pb, Hg, V, Ba, Co, La, Ag, Rb, Hf, Sc, Au and Cs) and metalloids (As and Sb), measured in different biotic matrices, with emphasis on guano, of the Chinstrap (Pygoscelis antarcticus), Adélie (Pygoscelis adeliae) and Gentoo (Pygoscelis papua) penguins. Regarding bioactive metals, the high concentrations (μg g−1 dry weight) of Cu (2.0 ± 1.4) x 102, Fe (4.1 ± 2.9) x 102, Mn (30 ± 34) and Zn (210 ± 90) reported in the guano from all the penguin species studied including our data, are of the same order of magnitude as those reported for whale feces (μg g−1 dry weight): Cu (2.9 ± 2.4) x 102, Fe (1.5 ± 1.4) x 102, Mn (28 ± 17) and Zn (6.2 ± 4.3) x 102, and one order of magnitude higher than the metal contents in krill (μg g−1 dry weight) of Cu (10.2 ± 5.5), Fe (24 ± 29) and Zn (13.5 ± 1.7). This suggest that penguin's excretion products could be an important source of these essential elements in the surface water, with an estimated annual release on a breeding season for Cu, Fe, Mn, Zn respectively of 28, 56, 4 and 29 tons, for the Chinstrap, Adélie and Gentoo penguins. The results provide evidence on the potential influence of penguins recycling TMs in the surface layer of the water column. © 2021 The Authors |
| Influence of Estuarine Water on the Microbial Community Structure of Patagonian Fjords | Frontiers in Marine Science | Tamayo-Leiva, J.; Cifuentes-Anticevic, J.; Aparicio-Rizzo, P.; Arroyo, J.; Masotti, I.; Díez, B. | 2021 | Zonas Costeras | 10.3389/fmars.2021.611981 | https://www.frontiersin.org/articles/10.3389/fmars.2021.611981/full | 611981 | Vol: 8 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | Fjords are sensitive areas affected by climate change and can act as a natural laboratory to study microbial ecological processes. The Chilean Patagonian fjords (41–56°S), belonging to the Subantarctic ecosystem (46–60°S), make up one of the world’s largest fjord systems. In this region, Estuarine Water (EW) strongly influences oceanographic conditions, generating sharp gradients of oxygen, salinity and nutrients, the effects of which on the microbial community structure are poorly understood. During the spring of 2017 we studied the ecological patterns (dispersal and oceanographic factors) underlying the microbial community distribution in a linear span of 450 km along the estuarine-influenced Chilean Patagonian fjords. Our results show that widespread microbial dispersion existed along the fjords where bacterioplankton exhibited dependence on the eukaryotic phytoplankton community composition. This dependence was particularly observed under the low chlorophyll-
a
conditions of the Baker Channel area, in which a significant relationship was revealed between SAR11 Clade III and the eukaryotic families Pyrenomonadaceae (Cryptophyte) and Coccomyxaceae (Chlorophyta). Furthermore, dissolved oxygen and salinity were revealed as the main drivers influencing the surface marine microbial communities in these fjords. A strong salinity gradient resulted in the segregation of the Baker Channel prokaryotic communities from the rest of the Patagonian fjords. Likewise, Microbacteriaceae, Burkholderiaceae and SAR11 Clade III, commonly found in freshwater, were strongly associated with EW conditions in these fjords. The direct effect of EW on the microbial community structure and diversity of the fjords exemplifies the significance that climate change and, in particular, deglaciation have on this marine region and its productivity. |
| Comité Científico de Cambio Climático: La importancia de la ventilación | | Tolvett, S.; Rondanelli, R.; Brevis, W.; Valdes, M.; Rojas, M. | 2021 | Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://comitecientifico.minciencia.gob.cl/wp-content/uploads/2021/06/Tolvett-ventilacion_11.pdf | | | | | | | |
| A source of isotopically light organic carbon in a low-pH anoxic marine zone | Nature Communications | Vargas, C.; Cantarero, S.; Sepúlveda, J.; Galán, A.; De Pol-Holz, R.; Walker, B.; Schneider, W.; Farías, L.; D’Ottone, M.; Walker, J.; Xu, X.; Salisbury, J. | 2021 | Zonas Costeras | 10.1038/s41467-021-21871-4 | http://www.nature.com/articles/s41467-021-21871-4 | 1604 | Vol: 12 Issue: 1 | 2041-1723 | Thomson Reuters ISI (SCIE) | | English | Geochemical and stable isotope measurements in the anoxic marine zone (AMZ) off northern Chile during periods of contrasting oceanographic conditions indicate that microbial processes mediating sulfur and nitrogen cycling exert a significant control on the carbonate chemistry (pH, A
T
, DIC and
p
CO
2
) of this region. Here we show that in 2015, a large isotopic fractionation between DIC and POC, a DIC and N deficit in AMZ waters indicate the predominance of in situ dark carbon fixation by sulfur-driven autotrophic denitrification in addition to anammox. In 2018, however, the fractionation between DIC and POC was significantly lower, while the total alkalinity increased in the low-pH AMZ core, suggesting a predominance of heterotrophic processes. An isotope mass-balance model demonstrates that variations in the rates of sulfur- and nitrogen-mediated carbon fixation in AMZ waters contribute ~7–35% of the POC exported to deeper waters. Thus, dark carbon fixation should be included in assessments of future changes in carbon cycling and carbonate chemistry due to AMZ expansion. |
| The Chilean Tornado Outbreak of May 2019: Synoptic, mesoscale, and historical contexts | Bulletin of the American Meteorological Society | Vicencio, J.; Rondanelli, R.; Campos, D.; Valenzuela, R.; Garreaud, R.; Reyes, A.; Padilla, R.; Abarca, R.; Barahona, C.; Delgado, R.; Nicora, G. | 2021 | Agua y Extremos; Zonas Costeras | 10.1175/BAMS-D-19-0218.1 | https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-19-0218.1/BAMS-D-19-0218.1.xml | E611-E634 | Vol: 102 Issue: 3 | 0003-0007, 1520-0477 | Thomson Reuters ISI (SCIE) | | English | In late May 2019, at least seven tornadoes were reported within a 24-h period in southern Chile (western South America, 36°–38°S), including EF1 and EF2 events causing substantial damage to infrastructure, dozens of injuries, and one fatality. Despite anecdotal evidence and chronicles of similar historical events, the threat from tornadoes in Chile was regarded with skepticism until the 2019 outbreak. Herein, we describe the synoptic-scale features instrumental in the development of these tornadic storms, including an extended southwest–northeast trough along the South Pacific, with a large postfrontal instability area. Tornadic storms appear to be embedded in a modestly unstable environment (positive convective available potential energy but less than 1,000 J kg−1) and strong low- and midlevel wind shear, with high near-surface storm-relative helicity values (close to −200 m2 s−2), clearly differing from the Great Plains tornadoes in North America (with highly unstable environments) but resembling cold-season tornadoes previously observed in the midlatitudes of North America, Australia, and Europe. Reanalyzing rainfall and lightning data from the last 10 years, we found that tornadic storms in our region occur associated with locally extreme values of both CAPE and low-level wind shear, where a combination of the two in a low-level vorticity generation parameter appears as a simple first-order discriminant between tornadic and nontornadic environments. Future research should thoroughly examine historical events worldwide to assemble a database of high-shear, low-CAPE midlatitude storms and help improve our understanding of these storms’ underlying physics. |
| Low-Cost Ka-Band Cloud Radar System for Distributed Measurements within the Atmospheric Boundary Layer | Remote Sensing | Aguirre, R.; Toledo, F.; Rodríguez, R.; Rondanelli, R.; Reyes, N.; Díaz, M. | 2020 | Zonas Costeras | 10.3390/rs12233965 | https://www.mdpi.com/2072-4292/12/23/3965 | 3965 | Vol: 12 Issue: 23 | 2072-4292 | Thomson Reuters ISI (SCIE) | | English | Radars are used to retrieve physical parameters related to clouds and fog. With these measurements, models can be developed for several application fields such as climate, agriculture, aviation, energy, and astronomy. In Chile, coastal fog and low marine stratus intersect the coastal topography, forming a thick fog essential to sustain coastal ecosystems. This phenomenon motivates the development of cloud radars to boost scientific research. In this article, we present the design of a Ka-band cloud radar and the experiments that prove its operation. The radar uses a frequency-modulated continuous-wave with a carrier frequency of 38 GHz. By using a drone and a commercial Lidar, we were able to verify that the radar can measure reflectivities in the order of −60 dBZ at 500 m of distance, with a range resolution of 20 m. The lower needed range coverage imposed by our case of study enabled a significant reduction of the instrument cost compared to existent alternatives. The portability and low-cost of the designed instrument enable its implementation in a distributed manner along the coastal mountain range, as well as its use in medium-size aerial vehicles or balloons to study higher layers. The main features, limitations, and possible improvements to the current instrument are discussed. |
| Taxonomic Novelty and Distinctive Genomic Features of Hot Spring Cyanobacteria | Frontiers in Genetics | Alcorta, J.; Alarcón-Schumacher, T.; Salgado, O.; Díez, B. | 2020 | Zonas Costeras | 10.3389/fgene.2020.568223 | https://www.frontiersin.org/articles/10.3389/fgene.2020.568223/full | 568223 | Vol: 11 | 1664-8021 | Thomson Reuters ISI (SCIE) | | English | Several cyanobacterial species are dominant primary producers in hot spring microbial mats. To date, hot spring cyanobacterial taxonomy, as well as the evolution of their genomic adaptations to high temperatures, are poorly understood, with genomic information currently available for only a few dominant genera, including Fischerella and Synechococcus. To address this knowledge gap, the present study expands the genomic landscape of hot spring cyanobacteria and traces the phylum-wide genomic consequences of evolution in high temperature environments. From 21 globally distributed hot spring metagenomes, with temperatures between 32 and 75°C, 57 medium- and high-quality cyanobacterial metagenome-assembled genomes were recovered, representing taxonomic novelty for 1 order, 3 families, 15 genera and 36 species. Comparative genomics of 93 hot spring genomes (including the 57 metagenome-assembled genomes) and 66 non-thermal genomes, showed that the former have smaller genomes and a higher GC content, as well as shorter proteins that are more hydrophilic and basic, when compared to the non-thermal genomes. Additionally, the core accessory orthogroups from the hot spring genomes of some genera had a greater abundance of functional categories, such as inorganic ion metabolism, translation and post-translational modifications. Moreover, hot spring genomes showed increased abundances of inorganic ion transport and amino acid metabolism, as well as less replication and transcription functions in the protein coding sequences. Furthermore, they showed a higher dependence on the CRISPR-Cas defense system against exogenous nucleic acids, and a reduction in secondary metabolism biosynthetic gene clusters. This suggests differences in the cyanobacterial response to environment-specific microbial communities. This phylum-wide study provides new insights into cyanobacterial genomic adaptations to a specific niche where they are dominant, which could be essential to trace bacterial evolution pathways in a warmer world, such as the current global warming scenario. |
| Influence of coastal upwelling on micro-phytoplankton variability at Valparaíso Bay (~33ºS), Central Chile | Revista de Biología Marina y Oceanografía | Aparicio-Rizzo, P.; Masotti, I.; Landaeta, M. | 2020 | Zonas Costeras | 10.22370/rbmo.2020.55.1.2353 | https://revistas.uv.cl/index.php/rbmo/article/view/2353 | 11 | Vol: 55 Issue: 1 | 0718-1957, 0717-3326 | Thomson Reuters ISI (SCIE) | | English | In this work 10 years of data (1986-1996) from a fixed station located in the northern part of Valparaíso Bay (33º00’S; 71º35’W) were analysed to study the influence of coastal upwelling activity on the temporal variation of micro-phytoplankton (20-200 μm) and their relationship with oceanographic conditions. The upwelling activity at the bay was associated to semi-annual wind regime with an intensification of upwelling-favourable S-SW winds from September to March followed by a decrease and the occurrence of downwelling events from April to August. Oceanographic conditions showed the ascent of cold, nutrient-rich salty water in spring (September-November). However, during summertime under highest upwelling index, thermal stratification conditions were registered. This stratification might be associated to either the solar radiation or the presence of an upwelling shadow area in the bay. The upwelling period had the highest micro-phytoplankton abundance mainly dominated by diatoms. This period was associated with an increase in biomass and richness in the bay. Meanwhile during non-upwelling period —under homogenous conditions of temperature, salinity and nutrients— an increase in diversity (but low abundance and richness) associated to dinoflagellates and silicoflagellates was noted. Therefore, the results suggest the presence of a bi-modal regime of micro-phytoplankton in the bay in response to changes in oceanographic conditions related to local wind forcing and mixing/stratification. |
| A multiscale analysis of the tornadoes of 30–31 May 2019 in south-central Chile | Atmospheric Research | Barrett, B.; Marin, J.; Jacques-Coper, M. | 2020 | Zonas Costeras | 10.1016/j.atmosres.2019.104811 | https://linkinghub.elsevier.com/retrieve/pii/S0169809519310683 | 104811 | Vol: 236 | 01698095 | Thomson Reuters ISI (SCIE) | | English | On 30 and 31 May 2019, tornadoes occurred in the cities of Los Angeles and Talcahuano/Concepción in south-central Chile, in a region where tornado activity is not common. The main goal of this study was to analyze these tornadoes across multiple scales: synoptic, mesoscale, and subseasonal. On the synoptic scale, the tornadoes were associated with an anomalous 500-hPa trough and associated surface cyclone to the west of Chile. A strong (20+ m s−1) low-level jet accompanied this trough, potentially enhanced by flow blocking by the Andes. A relatively warm and saturated surface layer combined with cold upper-level temperatures in the trough to yield 200–500 J kg−1 of CAPE on both days. This CAPE was accompanied by high levels of both deep-layer and low-level shear. Storm motions inferred by lightning swaths and GOES-IR imagery, along with estimates of storm motion and updraft helicity from a high-resolution WRF simulation, suggested this CAPE-shear combination was sufficient for the tornadic thunderstorms to be supercells. Finally, anomalies of sea level pressure, 500-hPa height, and surface dew point temperature from 27 to 31 May 2019 resembled long-term composite anomalies for MJO phases 1 and 2, suggesting a subseasonal link between the extreme event in Chile and convection in the tropics. |
| Late Quaternary climatic variability in northern Patagonia, Argentina, based on δ18O of modern and fossil shells of Amiantis purpurata (Bivalvia, Veneridae) | Palaeogeography, Palaeoclimatology, Palaeoecology | Bayer, S.; Beierlein, L.; Morán, G.; Doldán, M.; Morsan, E.; Brey, T.; Mackensen, A.; Farías, L.; García, G.; Gordillo, S. | 2020 | Zonas Costeras | 10.1016/j.palaeo.2020.110012 | https://linkinghub.elsevier.com/retrieve/pii/S0031018220304570 | 110012 | Vol: 560 | 00310182 | Thomson Reuters ISI (SCIE) | | English | Amiantis purpurata is a common warm-temperate water bivalve species distributed from southern Brazil to northern Patagonia, Argentina, which has a rich and well preserved fossil record in the San Matías Gulf (SMG) dating back to the late Quaternary. This study aims to establish A. purpurata shells as a new palaeoarchive of past marine conditions in South America. We compared the stable oxygen and carbon profiles (δ18Oshell; δ13Cshell) of eleven specimens of A. purpurata from different geological times (modern, Late Holocene and interglacial Late Pleistocene), and additionally present in situ oxygen isotope values of seawater within SMG (δ18Owater). Using both sets of information, we calculated and reconstructed palaeowater temperatures for the Late Holocene and compared them to modern water temperatures. Our findings indicate that A. purpurata records past environmental parameters such as water temperatures on a seasonal scale and can therefore be considered a suitable candidate for future palaeoenvironmental reconstructions in Northern Patagonia. This study is the first step towards further stable isotope analyses on fossil A. purpurata shells, which will show whether and if so, to what extent, important global climate events such as the Neoglacial (Early Holocene), the Hypsithermal (Middle Holocene) and the Little Ice Age (Late Holocene) occurred in South America. |
| Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed, Reanalysis and Regional Climate Model Data | Advances in Atmospheric Sciences | Bozkurt, D.; Bromwich, D.; Carrasco, J.; Hines, K.; Maureira, J.; Rondanelli, R. | 2020 | Agua y Extremos; Zonas Costeras | 10.1007/s00376-020-9183-x | http://link.springer.com/10.1007/s00376-020-9183-x | 477-493 | Vol: 37 Issue: 5 | 0256-1530, 1861-9533 | Thomson Reuters ISI (SCIE) | | English | This study investigates the recent near-surface temperature trends over the Antarctic Peninsula. We make use of available surface observations, ECMWF’s ERA5 and its predecessor ERA-Interim, as well as numerical simulations, allowing us to contrast different data sources. We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km (PWRF-45) and 15 km (PWRF-15) spatial resolutions for the period 1991-2015. In addition, we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain (~50 km) for further comparisons. Results show that there is a marked windward warming trend except during summer. This windward warming trend is particularly notable in the autumn season and likely to be associated with the recent deepening of the Amundsen/Bellingshausen Sea low and warm advection towards the Antarctic Peninsula. On the other hand, an overall summer cooling is characterized by the strengthening of the Weddell Sea low as well as an anticyclonic trend over the Amundsen Sea accompanied by northward winds. The persistent cooling trend observed at the Larsen Ice Shelf station is not captured by ERA-Interim, whereas hindcast simulations indicate that there is a clear pattern of windward warming and leeward cooling. Furthermore, larger temporal correlations and lower differences exhibited by PWRF-15 illustrate the existence of the added value in the higher spatial resolution simulation. |
| Connection between Antarctic Ozone and Climate: Interannual Precipitation Changes in the Southern Hemisphere | Atmosphere | Damiani, A.; Cordero, R.; Llanillo, P.; Feron, S.; Boisier, J.; Garreaud, R.; Rondanelli, R.; Irie, H.; Watanabe, S. | 2020 | Agua y Extremos; Zonas Costeras | 10.3390/atmos11060579 | https://www.mdpi.com/2073-4433/11/6/579 | 579 | Vol: 11 Issue: 6 | 2073-4433 | Thomson Reuters ISI (SCIE) | | English | In this study, we explored the connection between anomalies in springtime Antarctic ozone and all-year precipitation in the Southern Hemisphere by using observations from 1960–2018 and coupled simulations for 1960–2050. The observations showed that this correlation was enhanced during the last several decades, when a simultaneously increased coupling between ozone and Southern Annular Mode (SAM) anomalies became broader, covering most of the following summer and part of the previous winter. For eastern Australia, the ozone–precipitation connection shows a greater persistence toward the following summer than for other regions. On the other hand, for South America, the ozone–precipitation correlation seems more robust, especially in the early summer. There, the correlation also covers part of the previous winter, suggesting that winter planetary waves could affect both parameters. Further, we estimated the sensitivity of precipitation to changes in Antarctic ozone. In both observations and simulations, we found comparable sensitivity values during the spring–summer period. Overall, our results indicate that ozone anomalies can be understood as a tracer of stratospheric circulation. However, simulations indicate that stratospheric ozone chemistry still contributes to strengthening the interannual relationship between ozone and surface climate. Because simulations reproduced most of the observed connections, we suggest that including ozone variability in seasonal forecasting systems can potentially improve predictions. |
| Significant decrease of photovoltaic power production by aerosols. The case of Santiago de Chile | Renewable Energy | Del Hoyo, M.; Rondanelli, R.; Escobar, R. | 2020 | Zonas Costeras | 10.1016/j.renene.2019.10.005 | https://linkinghub.elsevier.com/retrieve/pii/S096014811931496X | 1137-1149 | Vol: 148 | 0960-1481 | Thomson Reuters ISI (SCIE) | | English | Santiago de Chile frequently suffers from atmospheric pollution that contributes to the decrease of solarirradiance on the surface, leading to losses in the energy output of photovoltaic systems. In this study, asimple model is used to estimate the effect of aerosols on the solar irradiance over the city throughoutthe year, using as input AERONET sunphotometer data and other in-situ measurements. The results showreductions of 3.5% and 14.1% for global horizontal and direct normal irradiance respectively and an in-crease of 35.4% for diffuse horizontal irradiance between the actual condition in Santiago and a hypo-thetical atmosphere free of aerosols. These effects translate approximately to an annual difference in theenergy output of 7.2% and 8.7% for monocrystalline and amorphous silicon PV technologies respec-tively, and an annual difference of 16.4% for a CPV technology, showing that aerosols can have a sig-nificant effect on the photovoltaic energy production. |
| Nitrous oxide distribution in the continental shelf off Central Chile (2005-2009) | | Farías, L.; Faúndez, J. | 2020 | Zonas Costeras | 10.1594/PANGAEA.916020 | https://doi.pangaea.de/10.1594/PANGAEA.916020 | | | | Pangaea | | English | Continental shelves tend to have high standing stocks of organic carbon and high rates of primary production relative to the open ocean and serve as important link between land and the ocean interior and between the sediment and the water column, playing a key role in the N and C balance, and accounting for up to 50% of the total N loss. One of the widest continental shelves in the eastern South Pacific (ESP) is present off central Chile (36°S). This is an important geographic feature in terms of physical and biological interactions owing to the large area available for coupling between the benthic and pelagic systems. In addition, this area is subjected to a strong coastal upwelling during austral spring and summer; when winds shift to a predominantly northward direction, stressing the sea surface layer and producing an intense cross-shelf transport and uplift of Equatorial Subsurface waters (ESSW) over the shelf. The ESSW, characterized by high NO3- and low O2 content, promotes surface fertilization and, subsequently, intense organic matter respiration and remineralization at depth, along with an efflux of subsurface-accumulated N2O (Farías et al. 2009, Cornejo & Farías, 2012). Thus, periods of maximum productivity and intense suboxia, or even anoxia, when diverse electron donors (e.g., organic matter, NH4+, NO2-, H2S) are present, represent a potential hotspot for fixed N removal processes.We present a data set that has been obtained during different FIP cruises (Fondo de Investigaciones Pesqueras) (2005-2009) which consisted of several transects perpendicular to the coast between 35° and 40°S and from the coast to 77.8° W (central Chile). Data collected include classical oceanographic variables including N2O and important greenhouse gas. |
| Vertical profiles of nitrous oxide, methane and nutrients in coastal water of eastern South Pacific | | Farías, L.; Faúndez, J. | 2020 | Zonas Costeras | 10.1594/PANGAEA.922967 | https://doi.pangaea.de/10.1594/PANGAEA.922967 | | | | Pangaea | | English | Between February 8th and March 4th 2007 an oceanographic cruise (Galathea 3 expedition) on board of Research Vessel Vædderen (Denmark) was performed Legs 13 and 14 of that expedition were devoted to the study of the oxygen minimum zone off northern Chile and Peru The cruise track covered the area between Valparaiso-Chile (32°S) and northern Peru (7.5°S) from total amount of 18 stations visited, we present 21 station with relatively high vertical resolution of Nitrous oxide and other variables. The main objective of the cruise was to study of low oxygen conditions over microbial communities and metabolic pathways related to the N and C cycles. In this region, an emblematic Oxygen Minimum Zone (OMZ), mainly defined by the presence of Subsurface Equatorial Waters (ESSW) between 50 and 400 m depth. These waters determine an important role of the eastern South Pacific in global climate related to the production of green house gases such as CO2, CH4 and N2O. During the cruise researcher was focused on several mechanisms of N and C transformation in the OMZ such as Fixation of molecular nitrogen (N2) and nitrous oxide (N2O) in surface waters and the core of the oxygen minimum zone and production and consumption of N2O by denitrificion and even nitrification.Continuously sampled variables:Temperature, salinity and disolved oxygen were obtained unsing a CTD-O probe (SeaBird)Discretely sampled variables:Water samples were collected using Niskin bottles attached to rosette sampler, in order to obtain discrete measurementsof dissolver oxygen (O2) and nutrients (NO3, NO2, SiO4 and PO43). Discrete samples of DO (in triplicate) were analyzed using the AULOX measurement system, an automatic Winkler method. Samples for NO2, NO3 and PO4 (15 mL in triplicate) were filtered (using a 0.45 μm GF/F glass filter) and stored (frozen) until analysis, using standard colorimetric techniques (Grasshoff, 1983). Measurements of NH4 (40 mL, in triplicate) were carried out using the fluorometric method proposed by Holmes et al. (1999). N2O and CH4 samples were taken in triplicate in 20 mL vials and carefully sealed to avoid air bubbles. They were then preserved with 50 μL of saturated HgCl2 and stored in darkness until analysis. N2O and CH4 was analyzed by creating a 5 mL headspace of ultrapure Helium and then equilibrated to 40◦C. Mesurements were carried out through gas chromatography using an electron capture detector (Varian 3380) and Flame Ionization detector (Shimadzu 17A), respectively. The calibration curves used 0.1, 0.5, and 1 ppm of N2O standards and 1, 2.5, 5 and 10 ppm of CH4 standards, both curves used pure He as 0 value. The analytical error for N2O measurements was ~3% and ~5% for CH4. CH4 was manually analyzed through a capillary column GS-Q (J&W, 0.53 mm×30 m) and 30°C oven temperature The uncertainty of the measurements was calculated from the standard deviation of the triplicate measurements by depth. Samples with a variation coefficient above 10% were not considered. |
| Temporal dynamics of dissolved inorganic nitrogen (DIN) in the aphotic layer of a coastal upwelling system with variable dissolved oxygen | Journal of Marine Systems | Farías, L.; Faúndez, J.; Sanhueza-Guevara, S. | 2020 | Zonas Costeras | 10.1016/j.jmarsys.2018.06.001 | https://linkinghub.elsevier.com/retrieve/pii/S0924796317302075 | 103087 | Vol: 209 | 0924-7963 | Thomson Reuters ISI (SCIE) | | English | Dissolved O2 (DO) concentration is critical to determining ecosystem functions such as organic matter respiration, which can favor fixed nitrogen loss and the accumulation of compounds such as NH4+. This dynamic is observed in central Chile's coastal upwelling system (36 °S), which presents seasonally O2 deficient waters and high biological productivity. Temporal dynamics for dissolved inorganic nitrogen (DIN: NO3−, NO2− and NH4+) are analyzed based on a ten year time series of monthly measurements of DO and DIN and a three year record of absolute DIN uptake rates (ρDIN), respective turnover rates (νDIN), and O2 utilization rates (OUR). Observed O2 deficit gradually increases from hypoxia to near anoxia as the system becomes more productive, favoring the accumulation of NO2− and NH4+. Three temporal phases within the aphotic layer were distinguished: (I) DO > 62 μmol L−1 (May to August), (II) 5 < DO < 62 μmol L−1 (September to December) and (III) DO < 5 μmol L−1 (January to April). From phase I to III, DO and NO3− inventories decreased by eight and two times, respectively, while NH4+ and NO2 inventories increased two- and five-fold, respectively. Uptake rates for NH4+ varied from 0.23 to 450 nmol N L−1 d−1 and from 1.42 to 184 nmol N L−1 d−1 for NO3−. Notably, integrated ρNH4+ increased during phase III, generating a NH4+ turnover time of 12–29 days; whereas integrated ρNO3− peaked during phase II, and removed the NO3− pool over an extended turnover time (>820 days). Integrated OUR gradually increased from phase I to III (from 225 to 422 mmol m−2 d−1), with DO pools replenished over 2.3 to 26 days. NH4+ regeneration rates ranged from 34 to 62 mmol m−2 d−1 and NH4+ pools were replenished within a few days. Variation in DO, which regulates N cycling, may explain the accumulation of N-species within the aphotic layer. Observed trends could be extrapolated to scenarios of upwelling-favorable winds, eutrophication and hypoxia. |
| South Pacific Subtropical High from the late Holocene to the end of the 21st century: insights from climate proxies and general circulation models | Climate of the Past | Flores-Aqueveque, V.; Rojas, M.; Aguirre, C.; Arias, P.; González, C. | 2020 | Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.5194/cp-16-79-2020 | https://cp.copernicus.org/articles/16/79/2020/ | 79-99 | Vol: 16 Issue: 1 | 1814-9332 | Thomson Reuters ISI (SCIE) | | English | The South Pacific Subtropical High (SPSH) is a
predominant feature of the South American climate. The variability of this
high-pressure center induces changes in the intensity of coastal alongshore
winds and precipitation, among others, over southwestern South America. In
recent decades, strengthening and expansion of the SPSH have been observed
and attributed to the current global warming. These changes have led to an
intensification of the southerly winds along the coast of northern to
central Chile and a decrease in precipitation from central to southern
Chile. Motivated by improving our understanding about the regional impacts
of climate change in this part of the Southern Hemisphere, we analyzed SPSH
changes during the two most extreme climate events of the last millennium,
the Little Ice Age (LIA) and the Current Warm Period (CWP: 1970–2000), based
on paleoclimate records and CMIP5/PMIP3 model simulations. In order to
assess the level of agreement of general circulation models, we also compare
them with ERA-Interim reanalysis data for the 1979–2009 period as a
complementary analysis. Finally, with the aim of evaluating future SPSH
behavior, we include 21st century projections under a Representative Concentration Pathway (RCP8.5) scenario in
our analyses. Our results indicate that during the relative warm (cold)
period, the SPSH expands (contracts). Together with this change, alongshore
winds intensify (weaken) south (north) of ∼35∘ S; also, southern westerly winds become stronger
(weaker) and shift southward (northward). Model results generally
underestimate reanalysis data. These changes are in good agreement with
paleoclimate records, which suggest that these variations could be related
to tropical climate dynamics but also to extratropical phenomena. However,
although models adequately represent most of the South American climate
changes, they fail to represent the Intertropical Convergence Zone–Hadley cell system dynamics, emphasizing the importance of improving
tropical system dynamics in simulations for a better understanding of its
effects on South America. Climate model projections indicate that changes
recently observed will continue during the next decades, highlighting the need
to establish effective mitigation and adaptation strategies against their
environmental and socioeconomic impacts. |
| The Central Chile Mega Drought (2010–2018): A climate dynamics perspective | International Journal of Climatology | Garreaud, R.; Boisier, J.; Rondanelli, R.; Montecinos, A.; Sepúlveda, H.; Veloso‐Aguila, D. | 2020 | Agua y Extremos; Zonas Costeras | 10.1002/joc.6219 | https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6219 | 421-439 | Vol: 40 Issue: 1 | 0899-8418 | Thomson Reuters ISI (SCIE) | | English | Central Chile, home to more than 10 million inhabitants, has experienced an uninterrupted sequence of dry years since 2010 with mean rainfall deficits of 20–40%. The so‐called Mega Drought (MD) is the longest event on record and with few analogues in the last millennia. It encompasses a broad area, with detrimental effects on water availability, vegetation and forest fires that have scaled into social and economical impacts. Observations and reanalysis data reveal that the exceptional length of the MD results from the prevalence of a circulation dipole‐hindering the passage of extratropical storms over central Chile—characterized by deep tropospheric anticyclonic anomalies over the subtropical Pacific and cyclonic anomalies over the Amundsen–Bellingshausen Sea. El Niño Southern Oscillation (ENSO) is a major modulator of such dipole, but the MD has occurred mostly under ENSO‐neutral conditions, except for the winters of 2010 (La Niña) and 2015 (strong El Niño). Climate model simulations driven both with historical forcing (natural and anthropogenic) and observed global SST replicate the south Pacific dipole and capture part of the rainfall anomalies. Idealized numerical experiments suggest that most of the atmospheric anomalies emanate from the subtropical southwest Pacific, a region that has experienced a marked surface warming over the last decade. Such warming may excite atmospheric Rossby waves whose propagation intensifies the circulation pattern leading to dry conditions in central Chile. On the other hand, anthropogenic forcing (greenhouse gases concentration increase and stratospheric ozone depletion) and the associated positive trend of the Southern Annular Mode also contribute to the strength of the south Pacific dipole and hence to the intensity and longevity of the MD. Given the concomitance of the seemingly natural (ocean sourced) and anthropogenic forcing, we anticipate only a partial recovery of central Chile precipitation in the decades to come. |
| Informe a las naciones: Incendios en Chile: causas, impactos y resiliencia. | | González, M.; Sapiains A., R.; Gómez-González, S.; Garreaud, R.; Miranda, A.; Galleguillos, M.; Jacques-Coper, M.; Pauchard, A.; Hoyos-Santillan, J.; Cordero, L.; Vasquez-Lavin, F.; Lara, A.; Aldunce, P.; Delgado, V.; Arriagada, R.; Ugarte, A.; Sepulveda-Jauregui, A.; Farías, L.; Garcia, R.; Rondane... | 2020 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2020/01/Informe-CR2-IncendiosforestalesenChile.pdf | 84 | | | | | Spanish | Los resultados presentados en este informe son parte del trabajo interdisciplinario que realiza el Centro de Ciencia
del Clima y la Resiliencia (CR)2.
El (CR)2 es un centro de excelencia financiado por el programa FONDAP de CONICYT (Proyecto 15110009) en el cual
participan cerca de 60 científicos asociados a la Universidad de Chile, la Universidad de Concepción y la Universidad
Austral de Chile.
La versión electrónica de este documento está disponible en el sitio web www.cr2.cl/incendios |
| Metagenomic Insights into the Sewage RNA Virosphere of a Large City | Viruses | Guajardo-Leiva, S.; Chnaiderman, J.; Gaggero, A.; Díez, B. | 2020 | Zonas Costeras | 10.3390/v12091050 | https://www.mdpi.com/1999-4915/12/9/1050 | 1050 | Vol: 12 Issue: 9 | 1999-4915 | Thomson Reuters ISI (SCIE) | | English | Sewage-associated viruses can cause several human and animal diseases, such as gastroenteritis, hepatitis, and respiratory infections. Therefore, their detection in wastewater can reflect current infections within the source population. To date, no viral study has been performed using the sewage of any large South American city. In this study, we used viral metagenomics to obtain a single sample snapshot of the RNA virosphere in the wastewater from Santiago de Chile, the seventh largest city in the Americas. Despite the overrepresentation of dsRNA viruses, our results show that Santiago’s sewage RNA virosphere was composed mostly of unknown sequences (88%), while known viral sequences were dominated by viruses that infect bacteria (60%), invertebrates (37%) and humans (2.4%). Interestingly, we discovered three novel genogroups within the Picobirnaviridae family that can fill major gaps in this taxa’s evolutionary history. We also demonstrated the dominance of emerging Rotavirus genotypes, such as G8 and G6, that have displaced other classical genotypes, which is consistent with recent clinical reports. This study supports the usefulness of sewage viral metagenomics for public health surveillance. Moreover, it demonstrates the need to monitor the viral component during the wastewater treatment and recycling process, where this virome can constitute a reservoir of human pathogens. |
| Assessment of ECMWF SEAS5 seasonal forecast performance over South America | Weather and Forecasting | Gubler, S.; Sedlmeier, K.; Bhend, J.; Avalos, G.; Coelho, C.; Escajadillo, Y.; Jacques-Coper, M.; Martinez, R.; Schwierz, C.; de Skansi, M.; Spirig, C. | 2020 | Zonas Costeras | 10.1175/WAF-D-19-0106.1 | http://journals.ametsoc.org/doi/10.1175/WAF-D-19-0106.1 | 561-584 | Vol: 35 Issue: 2 | 0882-8156, 1520-0434 | Thomson Reuters ISI (SCIE) | | English | Seasonal predictions have a great socio-economic potential if they are reliable and skillful. In this study, we assess the prediction performance of SEAS5, version 5 of the seasonal prediction system of the European Centre for Medium-Range Weather Forecasts (ECMWF), over South America against homogenized station data. For temperature, we find highest prediction performances in the tropics during austral summer, where the probability that the predictions correctly discriminate different observed outcomes is 70%. In regions lying to the east of the Andes, the predictions of maximum and minimum temperature still exhibit considerable performance, while further to the south in Chile and Argentina the temperature prediction performance is low. Generally, the prediction performance of minimum temperature is slightly lower than for maximum temperature. The prediction performance of precipitation is generally lower and spatially and temporally more variable than for temperature. The highest prediction performance is observed at the coast and over the highlands of Colombia and Ecuador, over north-eastern part of Brazil, and over an isolated region to the north of Uruguay during DJF.
In general, Nino3.4 has a strong influence on both air temperature and precipitation in the regions where ECMWF SEAS5 shows high performance, in some regions through teleconnections (e.g., to the north of Uruguay). However, we show that SEAS5 outperforms a simple empirical prediction based on Nino3.4 in most regions where the prediction performance of the dynamical model is high, thereby supporting the potential benefit of using a dynamical model instead of statistical relationships for predictions at the seasonal scale. |
| Informe a las naciones: El aire que respiramos: pasado, presente y futuro – Contaminación atmosférica por MP2,5 en el centro y sur de Chile | | Huneeus, N.; Urquiza, A.; Gayo, E.; Osses, M.; Arriagada, R.; Valdés, M.; Álamos, N.; Amigo, C.; Arrieta, D.; Basoa, K.; Billi, M.; Blanco, G.; Boisier, J.; Calvo, R.; Casielles, I.; Castro, M.; Chahúan, J.; Christie, D.; Cordero, L.; Correa, V.; Cortés, J.; Fleming, Z.; Gajardo, N.; Gallardo, L.; G... | 2020 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2020/09/Informe_Contaminacion_Espanol_2020.pdf | 102 | | | Not indexed | | Spanish | Los resultados presentados en este informe son parte del trabajo interdisciplinario que realiza el Centro de Ciencia
del Clima y la Resiliencia (CR)2.
El (CR)2 es un centro de excelencia financiado por el programa FONDAP de CONICYT (Proyecto 15110009) en el cual
participan cerca de 60 científicos asociados a la Universidad de Chile, la Universidad de Concepción y la Universidad
Austral de Chile.
La versión electrónica de este documento está disponible en el sitio web www.cr2.cl/incendios |
| Soil microbial community responses to labile organic carbon fractions in relation to soil type and land use along a climate gradient | Soil Biology and Biochemistry | Ramírez, P.; Fuentes-Alburquenque, S.; Díez, B.; Vargas, I.; Bonilla, C. | 2020 | Zonas Costeras | 10.1016/j.soilbio.2019.107692 | https://linkinghub.elsevier.com/retrieve/pii/S0038071719303566 | 107692 | Vol: 141 | 00380717 | Thomson Reuters ISI (SCIE) | | English | There has been a growing interest in studying the labile C pool in order to promote the sequestration and stabilization of soil organic carbon (SOC). Although labile SOC fractions have emerged as standardized indicators because of their potential to detect early SOC trends over time, the relationships between microbial attributes and labile SOC remains poorly understood. In this study, we explored the influence of labile SOC fractions on the topsoil bacteria-archaea community across 28 sites with different land use, climate aridity, and soil types across a wide range of SOC content (0.6–12%) in central Chile. We applied Illumina sequencing to the 16S rRNA to examine shifts in the diversity and composition of these soil microbial communities. Additionally, labile SOC fractions such as the permanganate oxidizable carbon (POXC) and light fraction organic matter (LFOM), along with the soil physicochemical properties were analyzed. The results demonstrated that among all of the environmental factors tested, the pH, POXC/SOC ratio and LFOM were key drivers of microbial community structure (β-diversity). The α-diversity metrics exhibited a decreasing trend when aridity increased, and community structure was found to vary, with high POXC/SOC in sites associated with drier conditions. In addition, POXC/SOC ratios and LFOM were clearly related to shifts in the relative abundances of specific taxonomic groups at genera level. When there was high POXC/SOC and low LFOM content, members of Bacteroidetes (Adhaeribacter, Flavisolibacter, and Niastella), Proteobacteria (Skermanella, Ramlibacter, and Sphingomonas), and Archaea (Thaumarchaeota) were found to be the most dominant groups; however, the microbial taxa responded differently to both labile C fraction types. These results have implications for understanding how labile C content can potentially be used to predict shifts in the microbial community, thus facilitating the development of predictive ecosystem models, as well as early warning indicators for soil degradation. |
| Fermentation and Anaerobic Oxidation of Organic Carbon in the Oxygen Minimum Zone of the Upwelling Ecosystem Off Concepción, in Central Chile | Frontiers in Marine Science | Srain, B.; Sobarzo, M.; Daneri, G.; González, H.; Testa, G.; Farías, L.; Schwarz, A.; Pérez, N.; Pantoja-Gutiérrez, S. | 2020 | Zonas Costeras | 10.3389/fmars.2020.00533 | https://www.frontiersin.org/article/10.3389/fmars.2020.00533/full | 533 | Vol: 7 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | We studied the dynamics of fermentation and anaerobic degradation of organic matter at a fixed station in the Oxygen Minimum Zone (OMZ) within the Humboldt Current System off Concepción, central Chile. Products of the main anaerobic microbial reactions fermentation, denitrification, and reduction of Fe(OH)3 and SO42– were analyzed during laboratory incubations of OMZ waters. Fermentation of glucose and amino acids resulted in the production of volatile fatty acids, mainly acetate; these compounds were detected year-round in in situ water samples and were associated with high primary production rates and presence of O2-deficient waters at the sampling site. In contrast, whilst ethanol was produced from glucose fermentation by OMZ water microorganisms under laboratory conditions, it was not detected in the water column during the annual cycle. Evidence of acetate oxidation (which is thermodynamically feasible), with Fe(OH)3 as an electron acceptor, suggests that microbial activity could reduce solid-phase Fe carried by rivers using fermented metabolites in oxygen-depleted water, thus releasing dissolved bioavailable Fe. Here we present evidence for productivity-driven seasonality of biogeochemical cycles in the Humboldt system, supported by fermentation and anaerobic consumption of fermentation products oxidized by a variety of electron acceptors including NO3–, Fe(OH)3, and SO42–. Our results suggest that products of fermentation in the OMZ may provide a source of labile organics for advection to oxygenated waters of subantarctic origin during austral winter. Fermentation, anaerobic oxidation and associated advection of fermentation products are likely to be enhanced during the twenty-first century due both to temperature increase and decrease in dissolved O2 in the water column. |
| Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment | Biogeosciences | Wilson, S.; Al-Haj, A.; Bourbonnais, A.; Frey, C.; Fulweiler, R.; Kessler, J.; Marchant, H.; Milucka, J.; Ray, N.; Suntharalingham, P.; Thornton, B.; Upstill-Goddard, R.; Weber, T.; Arévalo-Martínez, D.; Bange, H.; Benway, H.; Bianchi, D.; Borges, A.; Chang, B.; Crill, P.; del Valle, D.; Farías, L.;... | 2020 | Zonas Costeras | 10.5194/bg-17-5809-2020 | https://bg.copernicus.org/articles/17/5809/2020/ | 5809-5828 | Vol: 17 Issue: 22 | 1726-4189 | Thomson Reuters ISI (SCIE) | | English | Abstract. In the current era of rapid climate change, accurate
characterization of climate-relevant gas dynamics – namely production,
consumption, and net emissions – is required for all biomes, especially those
ecosystems most susceptible to the impact of change. Marine environments
include regions that act as net sources or sinks for numerous climate-active
trace gases including methane (CH4) and nitrous oxide (N2O). The
temporal and spatial distributions of CH4 and N2O are controlled
by the interaction of complex biogeochemical and physical processes. To
evaluate and quantify how these mechanisms affect marine CH4 and
N2O cycling requires a combination of traditional scientific
disciplines including oceanography, microbiology, and numerical modeling.
Fundamental to these efforts is ensuring that the datasets produced by
independent scientists are comparable and interoperable. Equally critical is
transparent communication within the research community about the technical
improvements required to increase our collective understanding of marine
CH4 and N2O. A workshop sponsored by Ocean Carbon and Biogeochemistry (OCB)
was organized to enhance dialogue and collaborations pertaining to
marine CH4 and N2O. Here, we summarize the outcomes from the
workshop to describe the challenges and opportunities for near-future
CH4 and N2O research in the marine environment. |
| Evidence of climate-driven changes on atmospheric, hydrological, and oceanographic variables along the Chilean coastal zone | Climatic Change | Winckler-Grez, P.; Aguirre, C.; Farías, L.; Contreras-López, M.; Masotti, Í. | 2020 | Zonas Costeras | 10.1007/s10584-020-02805-3 | http://link.springer.com/10.1007/s10584-020-02805-3 | 633-652 | Vol: 163 Issue: 2 | 0165-0009, 1573-1480 | Thomson Reuters ISI (SCIE) | | English | The Chilean coastal zone (CCZ) is subjected to a complex spectrum of anthropogenic, geophysical, biogeochemical, and climate-driven perturbations. Potentially affected variables including atmospheric sea level pressure (
Pa
), alongshore wind, sea surface temperature (
SST
), chlorophyll-a, rainfall, river discharge, relative mean sea level (
RMSL
), and wave climate are studied using in situ and satellite records, hindcasts, and reanalysis datasets. Linear temporal trends and correlations of anomalies are estimated between 18°S and 55°S along the CCZ. The comparison of some of the variables is achieved by means of a strict homogenization procedure on a monthly basis for 35 years. Our findings show that the poleward drift and strengthening of the Southeast Pacific Subtropical Anticyclone (SPSA) partially explains the increase in
Pa
and reduction in rainfall and river discharge. The enhancement of alongshore winds, also attributable to changes in the SPSA, increases coastal upwelling, which in turn could reduce
SST
and increase chlorophyll-a. Despite differential latitudinal responses, increasing wave heights and a southward rotation are evidenced.
RMSL
does not show significant variation as it is presumably affected by seafloor changes during the seismic cycle. Though some correlations are evidenced, the influence of climate variability at decadal scale (PDO, SAM) may be affecting the detected trends due to the short length of available data. Impacts on coastal communities, infrastructure, and ecosystems are discussed, aiming to highlight that coastal vulnerabilities and risk management should be based on the cumulative impacts of these variables. |
| Role of synoptic activity on projected changes in upwelling-favourable winds at the ocean’s eastern boundaries | npj Climate and Atmospheric Science | Aguirre, C.; Rojas, M.; Garreaud, R.; Rahn, D. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1038/s41612-019-0101-9 | http://www.nature.com/articles/s41612-019-0101-9 | 44 | Vol: 2 Issue: 1 | 2397-3722 | Thomson Reuters ISI (SCIE) | | English | The climate of the ocean’s eastern boundaries is strongly influenced by subtropical anticyclones, which drive a surface wind stress that promotes coastal upwelling of nutrient-rich subsurface water that supports high primary productivity and an abundance of food resources. Understanding the projected response of upwelling-favourable winds to climate change has broad implications for coastal biogeochemistry, ecology, and fisheries. Here we use a reanalysis, an ensemble of global climate simulations, and an objective algorithm to track anticyclones to investigate the projected changes in upwelling-favourable wind events at the California, Canary, Humboldt, and Benguela coastal upwelling systems. Except for the north Pacific, we find consistent poleward shifts of mean and upper percentile daily winds over the ocean basins. We propose that extratropical, synoptic-scale migratory anticyclones that force intense coastal upwelling events—which become more frequent at higher latitudes and less frequent at lower latitudes in the future—play an important role in the projected changes in upwelling-favourable wind events in these coastal upwelling systems. These changes complement large-scale processes such as the poleward shift of the subtropical ridge (STR) and stationary subtropical highs. Hence, both extratropical and tropical processes need to be considered to fully explain projected changes at the coastal upwelling systems under anthropogenic climate change. |
| Elucidating Viral Communities During a Phytoplankton Bloom on the West Antarctic Peninsula | Frontiers in Microbiology | Alarcón-Schumacher, T.; Guajardo-Leiva, S.; Antón, J.; Díez, B. | 2019 | Zonas Costeras | 10.3389/fmicb.2019.01014 | https://www.frontiersin.org/article/10.3389/fmicb.2019.01014/full | 1014 | Vol: 10 | 1664-302X | Thomson Reuters ISI (SCIE) | | English | In Antarctic coastal waters where nutrient limitations are low, viruses are expected to play a major role in the regulation of bloom events. Despite this, research in viral identification and dynamics is scarce, with limited information available for the Southern Ocean (SO). This study presents an integrative-omics approach, comparing variation in the viral and microbial active communities on two contrasting sample conditions from a diatom-dominated phytoplankton bloom occurring in Chile Bay in the West Antarctic Peninsula (WAP) in the summer of 2014. The known viral community, initially dominated by Myoviridae family (∼82% of the total assigned reads), changed to become dominated by Phycodnaviridae (∼90%), while viral activity was predominantly driven by dsDNA members of the Phycodnaviridae (∼50%) and diatom infecting ssRNA viruses (∼38%), becoming more significant as chlorophyll a increased. A genomic and phylogenetic characterization allowed the identification of a new viral lineage within the Myoviridae family. This new lineage of viruses infects Pseudoalteromonas and was dominant in the phage community. In addition, a new Phycodnavirus (PaV) was described, which is predicted to infect Phaeocystis antarctica, the main blooming haptophyte in the SO. This work was able to identify the changes in the main viral players during a bloom development and suggests that the changes observed in the virioplankton could be used as a model to understand the development and decay of blooms that occur throughout the WAP. © 2019 Alarcón-Schumacher, Guajardo-Leiva, Antón and Díez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
| Fischerella thermalis: a model organism to study thermophilic diazotrophy, photosynthesis and multicellularity in cyanobacteria | Extremophiles | Alcorta, J.; Vergara-Barros, P.; Antonaru, L.; Alcamán-Arias, M.; Nürnberg, D.; Díez, B. | 2019 | Zonas Costeras | 10.1007/s00792-019-01125-4 | http://link.springer.com/10.1007/s00792-019-01125-4 | 635-647 | Vol: 23 Issue: 6 | 1431-0651 | Thomson Reuters ISI (SCIE) | | English | The true-branching cyanobacterium Fischerella thermalis (also known as Mastigocladus laminosus) is widely distributed in hot springs around the world. Morphologically, it has been described as early as 1837. However, its taxonomic placement remains controversial. F. thermalis belongs to the same genus as mesophilic Fischerella species but forms a monophyletic clade of thermophilic Fischerella strains and sequences from hot springs. Their recent divergence from freshwater or soil true-branching species and the ongoing process of specialization inside the thermal gradient make them an interesting evolutionary model to study. F. thermalis is one of the most complex prokaryotes. It forms a cellular network in which the main trichome and branches exchange metabolites and regulators via septal junctions. This species can adapt to a variety of environmental conditions, with its photosynthetic apparatus remaining active in a temperature range from 15 to 58 °C.
Together with its nitrogen-fxing ability, this allows it to dominate in hot spring microbial mats and contribute signifcantly to the de novo carbon and nitrogen input. Here, we review the current knowledge on the taxonomy and distribution of F.thermalis, its morphological complexity, and its physiological adaptations to an extreme environment. |
| Inter-annual variability of oceanographic conditions and phytoplankton in Valparaíso Bay (~33°S), central Chile | Revista de Biología Marina y Oceanografía | Aparicio-Rizzo, P.; Masotti, I. | 2019 | Zonas Costeras | 10.22370/rbmo.2019.54.1.1495 | https://revistas.uv.cl/index.php/rbmo/article/view/1495 | 70 | Vol: 54 Issue: 1 | 0717-3326 | Thomson Reuters ISI (SCIE) | | English | The inter-annual variability of oceanographic conditions and phytoplankton abundance and biomass was studied using 10 years (1986-1996) of in situ observations at a fixed station in Valparaíso Bay (~33ºS). The time series analysis revealed that strong S-SW winds drive a quasi-permanent upwelling activity that maintain the nutrients availability in the water column to fuel the phytoplankton in the bay. The most important changes in bio-oceanographic conditions were observed during 1987 El Niño event, which was characterized by higher temperatures but lower values for salinity, nitrate, and phosphate concentrations, together with a decrease of phytoplankton biomass compared to 1988 La Niña event when colder, saltier, and nutrient-rich upwelled water were observed. High Aconcagua River discharges were observed during the El Niño conditions (1987-1988 and 1993), which led to a decrease in surface salinity and a high abundance of dinoflagellates. Two periods with differences in bio-oceanographic conditions were observed; 1988-1992 showed lower temperatures but higher nutrients (nitrate), phytoplankton biomass and abundance of diatoms than 1993-1996 period. Throughout the study period, positive trends in upwelling activity was registered accompanied by a fall in phytoplankton biomass and dinoflagellate abundance. This paper provides new evidences concerning the influence of El Niño Southern Oscillation (ENSO) in phytoplankton and oceanographic conditions in the coastal upwelling off central Chile. |
| A new method to evaluate the vulnerability of watersheds facing several stressors: A case study in mediterranean Chile | Science of The Total Environment | Arriagada, L.; Rojas, O.; Arumí, J.; Munizaga, J.; Rojas, C.; Farías, L.; Vega, C. | 2019 | Zonas Costeras | 10.1016/j.scitotenv.2018.09.237 | https://linkinghub.elsevier.com/retrieve/pii/S0048969718336817 | 1517-1533 | Vol: 651 | 0048-9697 | Thomson Reuters ISI (SCIE) | | English | Freshwater systems are subjected to multiple anthropogenic stressors and natural disturbances that act as debilitating agents and modifiers of river systems, causing cumulative and synergistic effects that deteriorate their health and result in watershed vulnerability. This study proposes an easy-to-apply spatial method of watershed vulnerability evaluation using Geographic Information Systems (GIS) in the Andalién River watershed, located in the Chilean mediterranean. A watershed vulnerability index (WVI) based on three sub-indices – anthropogenic stressors, environmental fragility and natural disturbances – was developed. To determine the index grouping weights, expert surveys were carried out using the Delphi method. We subsequently normalized and integrated the factors of each sub-index with relative weights. The ranges of each thematic layer were re-classified to establish vulnerability scores. The watershed was divided into three sections: headwaters zone, transfer zone and depositional zone. The watershed vulnerability index showed that 41% of the watershed had very low vulnerability and 42% had medium vulnerability, while only 1% – in the depositional zone – had high vulnerability. A one-way ANOVA was carried out to analyze the vulnerability differences among the three sections of the watershed; it showed significant differences (F (2, 16) = 8.15: p < 0.05). The a posteriori test showed differences between the headwaters and depositional zones (Tukey test, p = 0.005) and between the transfer and depositional zones (Tukey test, p = 0.014). To validate the WVI, water quality was measured at 16 stations in the watershed; there was a significant correlation between vulnerability level and NO2 − levels (r = 0.8; p = 0.87; α = 0.05) and pH (r = 0.8; p = 0.80; α = 0.05). The WVI showed the cumulative effects of multiple stressors in the depositional zone of the watershed. This is the first study to evaluate and validate non-regulated watershed vulnerability with GIS using multiple anthropogenic and natural stressors. |
| A Harmonized Nitrous Oxide (N2O) Ocean Observation Network for the 21st Century | Frontiers in Marine Science | Bange, H.; Arévalo-Martínez, D.; de la Paz, M.; Farías, L.; Kaiser, J.; Kock, A.; Law, C.; Rees, A.; Rehder, G.; Tortell, P.; Upstill-Goddard, R.; Wilson, S. | 2019 | Zonas Costeras | 10.3389/fmars.2019.00157 | https://www.frontiersin.org/article/10.3389/fmars.2019.00157/full | 157 | Vol: 6 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | Nitrous oxide (N2O) is an important atmospheric trace gas involved in tropospheric warming and stratospheric ozone depletion. Estimates of the global ocean contribution to N2O emissions average 21% (range: 10 to 53%). Ongoing environmental changes such as warming, deoxygenation and acidification are affecting oceanic N2O cycling and emissions to the atmosphere. International activities over the last decades aimed at improving estimates of global N2O emissions, including (i) the MarinE MethanE and NiTrous Oxide database (MEMENTO) for archiving of quality-controlled data, and (ii) a recent large-scale inter-laboratory comparison by Working Group 143 of the Scientific Committee on Ocean Research (SCOR). To reduce uncertainties in oceanic N2O emission estimates and to characterize the spatial and temporal variability in N2O distributions in a changing ocean, we propose the establishment of a harmonized N2O Observation Network (N2O-ON) combining discrete and continuous data from various platforms. The network will integrate observations obtained by calibrated techniques, using time series measurements at fixed stations and repeated hydrographic sections on voluntary observing ships and research vessels. In addition to exploiting existing oceanographic infrastructure, we propose the establishment of central calibration facilities in selected international laboratories to improve accuracy, and ensure standardization and comparability of N2O measurements. Final data products will include a harmonized global N2O concentration and emission fields for use in model validation and projections of future oceanic N2O emissions, to inform the global research community and policy makers. |
| Dynamical downscaling over the complex terrain of southwest South America: present climate conditions and added value analysis | Climate Dynamics | Bozkurt, D.; Rojas, M.; Boisier, J.; Rondanelli, R.; Garreaud, R.; Gallardo, L. | 2019 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1007/s00382-019-04959-y | http://link.springer.com/10.1007/s00382-019-04959-y | 6745-6767 | Vol: 53 Issue: 11 | 0930-7575 | Thomson Reuters ISI (SCIE) | | English | This study evaluates hindcast simulations performed with a regional climate model (RCM, RegCM4) driven by reanalysis data (ERA-Interim) over the Pacific coast and Andes Cordillera of extratropical South America. A nested domain configuration at \(0.44^{\circ }\) ( \(\sim\) 50 km) and \(0.09^{\circ }\) ( \(\sim\) 10 km) spatial resolutions is used for the simulations. RegCM4 is also driven by a global climate model (GCM, MPI-ESM-MR) on the same domain configuration to asses the added values for temperature and precipitation (historical simulations). Overall, both 10 km hindcast and historical simulation results are promising and exhibit a better representation of near-surface air temperature and precipitation variability compared to the 50 km simulations. High-resolution simulations suppress an overestimation of precipitation over the Andes Cordillera of northern Chile found with the 50 km simulations. The simulated daily temperature and precipitation extreme indices from 10 km hindcast simulation show a closer estimation of the observed fields. A persistent warm bias ( \(\sim +\,{4\,}^{\circ }\hbox {C}\) ) over the Atacama Desert in 10 km hindcast simulation reveals the complexity in representing land surface and radiative processes over the desert. Difficulties in capturing the temperature trend in northern Chile are notable for both hindcast simulations. Both resolutions exhibit added values for temperature and precipitation over large parts of Chile, in particular, the 10 km resolves the coastal-valley Andes transitions over central Chile. Our results highlight that resolutions coarser than 50 km (e.g., GCMs and reanalysis) miss important climate gradients imposed by complex topography. Given that the highest spatial resolution of the current regional simulations over the South America is about 50 km, higher resolutions are important to improve our understanding of the dynamical processes that determine climate over complex terrain and extreme environments. |
| Informe de Síntesis Simulaciones climáticas regionales para el continente Antártico | | Bozkurt, D.; Rondanelli, R.; Carrasco, J.; Boisier, J.; Morales, B.; Muñoz, F.; Valdebenito, N.; Del Hoyo, M.; Troncoso, M.; Bustos, S. | 2019 | Agua y Extremos; Zonas Costeras | | https://cambioclimatico.mma.gob.cl/wp-content/uploads/2020/05/Informe-sintesis-simulacionesantartica.pdf | | | | | | | |
| Informe de Síntesis Simulaciones climáticas regionales para el territorio insular Chileno | | Bozkurt, D.; Rondanelli, R.; Carrasco, J.; Boisier, J.; Morales, B.; Muñoz, F.; Valdebenito, N.; Del Hoyo, M.; Troncoso, M.; Bustos, S. | 2019 | Agua y Extremos; Zonas Costeras | | https://cambioclimatico.mma.gob.cl/wp-content/uploads/2020/05/Informe-sintesis-simulaciones-territorio-insular.pdf | | | | | | | |
| Comentarios Centro de Ciencia del Clima y la Resiliencia (CR)2 a la consulta ciudadana de primera actualización 2019 de la Contribución Determinada a Nivel Nacional (NDC) de Chile. Diciembre 2019 | | Centro de Ciencia del Clima y la Resiliencia (CR)2 | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Resumen-Comentarios-CR2_NDC-2019_02122019.pdf | | | | | | | |
| Comité Científico COP25: Propuesta para la actualización de Plan de Adaptación en Pesca y Acuicultura | | Farías, L.; Acuña, E.; Aguirre, C.; Álvarez, S.; Barbieri, M.; Delgado, V.; Dewitte, B.; Espinoza, Ó.; Fernández, C.; Garrido, P.; Jacob, B.; Lagos, N.; Masotti, I.; Narváez, D.; Navarrete, S.; Pérez-Santos, I.; Pinilla, E.; Ramajo, L.; Saavedra, L.; Silva, C.; Soto, D.; Troncoso, L.; Vargas, C.; Ve... | 2019 | Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Propuesta-de-actualización-para-Plan-de-Adaptación.pdf | 1-87 | | | | | English | El Plan de Adaptación al Cambio Climático en Pesca y Acuicultura (PACCPA) es un instrumento articulador
que delinea acciones y medidas relativas a políticas públicas y gestión pesquera y acuícola, con el objetivo de
fortalecer la capacidad de adaptación del sector al cambio climático. La Mesa Océanos del Comité Científico
COP25 presenta esta propuesta para la actualización y mejoramiento del PACCPA a la luz de los cambios
físicos, químicos y biológicos que afectan al océano, sean estos observados o proyectados; para la evaluación
de diferentes tipos de riesgos en la zona costera y otros antecedentes socioeconómicos, jurídicos, normativos
y de gobernanza que impactan positiva o negativamente sobre la actividad pesquera y acuícola.
El presente documento entrega observaciones y argumentos relativos a los 5 objetivos específicos y 29
acciones delineadas en el primer PACCPA (2015-2020); además, introduce 16 nuevas acciones asociadas a
tres de los objetivos ya planteados y agrega dos nuevos objetivos específicos relativos a fomentar e incentivar
la economía circular y fortalecer el rol de la mujer, para una mejor adaptación de las comunidades costeras.
Se introducen los nuevos antecedentes de: gobernanza climática internacional, en los cuales Chile tiene
compromisos, institucionalidad nacional y del marco normativo y jurídico con el cual administra y gestiona los
recursos marinos y la zona costera. Se releva la necesidad de reformar el concepto de enfoque ecosistémico y
principio precautorio de la Ley de Pesca y Acuicultura en un contexto de cambio climático y, explícitamente,
de incorporar la actividad acuícola bajo estos conceptos. Existe consenso de que la armonización de las estructuras de gobernanza local y/o macrozonas proporcionarán una política general de acción y asignación de
recursos necesarios para la adaptación.
Se analizan, además, los procesos y las variables oceanográficas y climáticas que afectan a las pesquerías
y a la acuicultura (no todas consideradas en el primer PACCPA), como acidificación, desoxigenación, estratificación, aumento de la intensidad de la surgencia y de la frecuencia de eventos El Niño, entre otros, además
de riesgos e impactos del aumento del nivel del mar y marejadas para el sector. Se resalta la necesidad de
profundizar en el conocimiento de parámetros biológicos relacionados con la reproducción, la alimentación y
la sobrevivencia de los recursos pesqueros y de cultivo a diferentes edades.
Con el análisis de planes existentes y nuevas evidencias, se levantaron brechas de conocimiento, gobernanza, ambientales y socioeconómicas; estas últimas importantes de ponderar, pues los trabajadores de este
sector son los que reciben los más bajos ingresos, poseen un menor nivel de educación y de salud y, por ello,
son más vulnerables. En este contexto, el cambio climático profundiza las desigualdades y es un multiplicador
de amenazas.
Se indica que muchas variables/procesos que afectan a los recursos biológicos (amenazas) no deben
ser analizados individualmente, sino como multi-amenazas, debido a la correlación que existe entre ellos;
asimismo, se debe realizar un fortalecimiento institucional, sistematizar y profundizar el conocimiento científico. Relativo a esto último, se repite una y otra vez la necesidad de un Sistema Integrado de Observación del
Océano Chileno (SIOOC) y el uso y mejoramiento de modelos regionales propios; donde se acoplen modelos
oceanográficos con los pesqueros con fines de predicción y comprensión de los mecanismos que entran en
juego, entre los recursos pesqueros y el efecto antrópico (como la sobrepesca), separando así la variabilidad
ambiental del cambio climático y la capacidad de adaptación.
Respecto a la acuicultura, también se requiere por una parte una evaluación profunda y analítica del impacto a nivel macro y microbiológico que ejercen los centros de cultivo sobre su entorno y cómo estos pueden
exacerbar la crisis climática en curso; además de cuantificar cómo los efectos del cambio climático (aumento
de temperatura, cambios en corrientes, acidificación, salinidad, oxigenación, etc.) impactan la sostenibilidad
y productividad del sector.
Finalmente, se concluye y recomienda que es vital incluir los aspectos socioeconómicos, de gobernanza y
financiamiento al nuevo PACCPA, considerando la diversidad de amenazas, pero también las oportunidades
que se presentan para el sector |
| Comité Científico COP25: Océano y Cambio Climático. 50 preguntas y respuestas | | Farías, L.; Aguilera, V.; Aguirre, C.; Barbieri, M.; Castillo-Silva, M.; Contreras-López, M.; Dewitte, B.; Echeveste, P.; Fernández, C.; Gómez-Canchong, P.; Lagos, N.; Lara, L.; Marquet, P.; Miquel, J.; Molina, M.; Montecino, V.; Morales, M.; Narváez, D.; Navarrete, S.; Oliveros-Clavijo, V.; Quiroga... | 2019 | Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/10/El-ABC-del-Océano-y-el-cambio-Cimático.pdf | 1-107 | | | | | Spanish | Todos los que habitamos el planeta dependemos directa o indirectamente del océano. Este provee alimento, transporte,
cultura y, a través del intercambio de agua, energía y carbono; asimismo, es sustento de hábitats únicos que han sido dañados
progresivamente por los efectos del cambio climático.
A nivel global 680 millones de personas habitan zonas costeras. En Chile, nuestra relación es todavía más estrecha. Debido a
nuestra extensa geografía, un cuarto de la población se distribuye en 100 comunas costeras donde más de 500 caletas dan sustento a 90 mil trabajadores vinculados a la pesca artesanal.
La creciente y cada vez más contundente evidencia científica sobre el impacto del cambio climático en los ecosistemas
marinos revela la vulnerabilidad a la que se exponen los habitantes y otros seres vivos de estos territorios, y, por lo mismo, es un llamado urgente que nos moviliza a la acción.
Como Ministerio de Ciencia, Tecnología, Conocimiento e Innovación trabajamos activamente con la comunidad científica
para utilizar la evidencia en el diseño de políticas que nos permitan sobreponernos y anticiparnos a los efectos del cambio
climático.
En esta búsqueda, y con motivo de la cumbre de acción climática COP25, hemos impulsado la organización del Comité
Científico que reúne a más de 550 investigadores nacionales del cambio climático. Este trabajo busca contribuir directamente
al tránsito que necesitamos desde la evidencia a la acción climática ambiciosa y factible.
Las siguientes páginas son el resultado del esfuerzo colectivo de los investigadores e investigadoras de la mesa Océanos
de este comité. Este documento es un aporte al debate ciudadano y a la necesaria sensibilización sobre la importancia de nuestro océano.
Solo si logramos comprender en profundidad procesos como el aumento del nivel del mar, sus cambios de temperatura,
acidificación, oxigenación, eventos extremos asociados al océano y la pérdida de biodiversidad que enfrenta, podremos
impulsar medidas de adaptación y mitigación que apunten a un desarrollo sostenible e integral en beneficio de las personas
y el medioambiente que lo permite. |
| Nitrous oxide and biogeochemical variables related to Intermediate Waters into Eastern South Pacific Ocean, supplement to: Carrasco, Cristina; Karstensen, Johannes; Farías, Laura (2017): On the Nitrous Oxide Accumulation in Intermediate Waters of the Eastern South Pacific Ocean. Frontiers in Marine Science, 4 | | Farías, L.; Carrasco, C.; Faúndez, J. | 2019 | Zonas Costeras | 10.1594/PANGAEA.906231 | https://doi.pangaea.de/10.1594/PANGAEA.906231 | | | | Pangaea | | English | Nitrous oxide (N2O) is a powerful greenhouse gas principally produced by nitrification and denitrification in the marine environment. Observations were made in the eastern South Pacific (ESP), between 10º and 60°S, and ~75° to 88°W, from intermediate waters targeting Antarctic Intermediate Water (AAIW) at potential density of 27.0-27.1 kg m-3. Between 60° to 20°S, a gradual equatorward increase of N2O from 8 to 26 nmol L-1 was observed at density 27.0-27.1 kg m-3 where AAIW penetrates. Positive correlations were found between apparent N2O production (∆N2O) and O2 utilization (AOU), and between ∆N2O and NO3-, which suggested that local N2O production is predominantly produced by nitrification. Closer to the equator, between 20° and 10°S at AAIW core, a strong N2O increase up to 75 nmol L-1 was observed. Because negative correlations were found between ∆N2O vs. NO3- and ∆N2O vs. N* (a Nitrogen deficit index) and because ∆N2O and AOU do not follow a linear trend, we suspect that, in addition to nitrification, denitrification also takes place in N2O cycling. By making use of water mass mixing analyses, we show that an increase in N2O occurs in the region where high oxygen from AAIW merges with low oxygen from Equatorial Subsurface Water (ESSW), creating favorable conditions for local N2O production. We conclude that the non-linearity in the relationship between N2O and O2 is a result of mixing between two water masses with very different source characteristics, paired with the different time frames of nitrification and denitrification processes that impact water masses en route before they finally meet and mix in the ESP region. |
| Comité Científico COP25: Propuesta de un Sistema Integrado de Observación del Océano Chileno | | Farías, L.; Fernández, C.; Garreaud, R.; Guzmán, L.; Hormazábal, S.; Morales, C.; Narváez, D.; Pantoja, S.; Pérez, I.; Soto, D.; Winckler, P. | 2019 | Agua y Extremos; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Propuesta-de-sistema-integrado-de-observación-del-océano.pdf | 1-27 | | | | | Spanish | Chile ocupa el décimo puesto a nivel mundial con mayor territorio marítimo y el primer lugar en Latinoamérica con mayor superficie de mar. El país es dependiente del océano en términos económicos, sociales y
culturales, que incluyen actividades en la zona costera y oceánica. Al mismo tiempo, los procesos climáticos
y oceanográficos constituyen constantes fuentes de riesgo e incertidumbre, aumentando la vulnerabilidad
en los socio-ecosistemas marinos. Chile está declarado un país altamente vulnerable al cambio climático,
basado en estudios derivados de la Agenda 2030 para el Desarrollo Sostenible de las Naciones Unidas. Esto
obliga a buscar propuestas y soluciones para abordar esta vulnerabilidad.
A nivel internacional, varios países han desarrollado e implementado sistemas integrados de observación
del océano basados en información continua sobre su estado y sus recursos, con el objetivo de abordar de
forma operacional la vulnerabilidad. Estos sistemas de observación tienen propósitos, tales como, mejorar la
seguridad en operaciones marinas, fortalecer la seguridad alimentaria, apoyar las actividades económicas de
pequeña y gran escala, reducir el riesgo frente a desastres naturales y disminuir la incertidumbre económica
junto con la conflictividad social y ambiental derivada de esta. El océano chileno está afecto a una serie de
procesos globales asociados al cambio climático, regionales y locales que necesitan, ser estudiados y monitoreados. Por lo tanto, se requiere de la existencia de un sistema de registro continuo de variables atmosféricas
y oceanográficas, que provea la información necesaria para la toma de decisiones, tanto públicas como privadas, y permita realizar análisis retrospectivos y predictivos del estado del océano.
Actualmente, existen en Chile algunas iniciativas de observación y monitoreo del océano, incluyendo
aportes de servicios públicos, instituciones académicas y organizaciones privadas. Sin embargo, estas no son
sistémicas y carecen de continuidad, principalmente por falta de instrumentos financieros de largo aliento y
de la valoración política de la información. En el compromiso nacional e internacional, el Comité Científico
COP25 releva la importancia de contar con información basada en la evidencia para planificar estratégicamente el desarrollo sostenible y la equidad intergeneracional respecto del uso y la conservación del océano,
de los ecosistemas marinos y sus servicios a la humanidad.
En este escenario, académicos, servidores públicos y agentes del sector privado con competencia en la
materia proponen gestar un Sistema Integrado de Observación del Océano Chileno (SIOOC), que permita
disponer de datos de calidad, estandarizados y de acceso público para el estudio, monitoreo, manejo y vigilancia del océano y sus recursos.
Se contemplan para la implementación del SIOOC, basado en la experiencia existente y las necesidades o
brechas del Chile, tres fases en un horizonte de 6 a 8 años:
› Primero, consolidar la integración de los sistemas existentes en una red asociativa y bajo una gobernanza apropiada, con recursos humanos y financiamiento de fuentes múltiples, e incluyendo
la participación del sector privado, productivo y de la sociedad civil.
› Segundo, incorporar al sistema de nuevos equipamientos e infraestructura (primario y secundario), con un análisis de las capacidades habilitantes y la transferencia tecnológica necesaria para
aumentar el tipo, número y cobertura de las observaciones, además de fortalecer las capacidades
de predicción.
› Tercero, incorporar en pleno del SIOOC a otras redes internacionales, especialmente en zonas de
alto interés, como la zona antártica, aguas internacionales e islas oceánicas.
Las universidades y los servicios del Estado participantes en esta propuesta comprometen la infraestructura y los conocimientos existentes para dar lanzamiento al SIOOC. A su vez, esperan que el Estado tome esta
iniciativa y un compromiso nacional e internacional como una acción para proteger nuestros mares. |
| Comité Científico COP25: Nueve medidas basadas en el océano para las Contribuciones Determinadas a nivel Nacional de Chile | | Farías, L.; Ubilla, K.; Aguirre, C.; Bedriñana, L.; Cienfugos, R.; Delgado, V.; Fernández, C.; Fernández, M.; Gaxiola, A.; González, H.; Hucke-Gaete, R.; Marquet, P.; Montencino, V.; Morales, C.; Narváez, D.; Osses, M.; Peceño, B.; Quiroga, E.; Ramajo, L.; Sepúlveda, H.; Soto, D.; Vargas, E.; Viddi,... | 2019 | Ciudades Resilientes; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/12/Nueve-soluciones-para-NDC.pdf | 1-93 | | | | | English | Las Contribuciones Determinadas a nivel Nacional (NDC, por sus siglas en inglés) se han convertido en un instrumento clave para comprometer principalmente metas de mitigación y adaptación al cambio climático. Gestadas en el Acuerdo de París (2015) aspiran a cumplir dos de sus objetivos más ambiciosos: mantener el incremento de la temperatura global muy por debajo de los 2°C, respecto a la era preindustrial, y fortalecer y aumentar la capacidad de adaptación y resiliencia a los efectos adversos del cambio climático. La actualización de las NDC el año 2020 las llevará a convertirse en un instrumento ambicioso y con trazabilidad, luego de la declaración de limitar a 1.5 °C el incremento de temperatura al 2030 (IPCC, 2018) y la cumbre del clima de Katowice (COP24). Chile, ejerciendo la presidencia de la COP25, se debe comprometer a metas más ambiciosas, transparentes y progresivas, entre ellas, la carbono- neutralidad, la COP azul y la economía circular. La mesa Océanos del Comité Científico COP25, a partir de una metodología participativa y colaborativa, propone nueve medidas basadas en el océano, para contribuir a la meta de reducción de sus emisiones, y realiza un análisis de los alcances que tiene la primera propuesta de actualización de las NDC (2020) en el tema océano. Las medidas propuestas en este informe colindan con acciones que: 1) favorecen el secuestro de carbono, como soluciones basada en naturaleza (carbono azul); 2) reducen las emisiones de gases con efecto invernadero (GEI) en la economía del océano; y 3) abordan la vulnerabilidad, riesgos e impactos del cambio climático en el sector pesca y acuicultura, enfocándose en la inequidad social y de género, y la construcción de capacidades relativa a implementar un sistema observación del océano y reducir brechas en su conocimiento, gestión y administración. Se refuerza en el concepto de entierro de carbono como el resultado del funcionamiento a largo plazo de una compleja red de procesos del ciclo del carbono, donde los sedimentos marinos y suelos costeros se constituyen como el mayor reservorio de largo aliento de carbono en el planeta. Al respecto, se reúnen antecedentes de la ventaja competitiva que tiene Chile respecto a la protección de fondos marinos, marismas y bosques de algas pardas; ecosistemas de fundamental importancia para la mitigación del cambio climático, pero, específicamente, vulnerables a su impacto y a la acción humana. Respecto a la economía del océano, la reducción de la emisión de GEI por parte de actividades como el transporte marítimo, acuicultura y el uso de energías marinas son medidas muy factibles e internacionalmente comprobadas, cuyos costos-beneficios van en directa relación con los compromisos y mercados internacionales. Este es especialmente relevante para la acuicultura y la economía circular. Finalmente, para adaptarse deben existir capacidades en un Sistema Integrado de Observación del Océano Chileno (SIOOC) que incluya alertas ambientales tempranas y proyecciones, de modo de reducir riesgos y conflictividades ambientales y sociales, y disminuir las brechas de conocimiento, de gobernanza y económicas respecto al océano. Lo que importa es transformar los compromisos en acciones/medidas trazables, y al respecto, dada su vocación oceánica y su dependencia a este medio, Chile debe tener unas NDC ambiciosas que incluyan los hábitats y ecosistemas marinos (carbono azul) en los presupuestos de carbono nacional (además de las contribuciones en materia de cambio de uso de la tierra y silvicultura, UTCUTS), declarar co-beneficios, dar valoración económica de los servicios ecosistémicos ambientales, y formular políticas públicas dirigidas a la conservación. El presente informe releva la necesidad de generar voluntad política para fortalecer el marco normativo y/o legislativo que permita proteger a los sistemas costeros que cumplen importantes funciones para el cambio climático; fortalecer la capacidad adaptativa de las comunidades pesqueras y acuicultoras, y comprometer Áreas Marinas Protegidas con planes de manejo al corto plazo de modo de aumentar el nivel de ambición y alcanzar la carbono neutralidad. |
| Bacterial community structure in a sympagic habitat expanding with global warming: brackish ice brine at 85–90 °N | The ISME Journal | Fernández-Gómez, B.; Díez, B.; Polz, M.; Arroyo, J.; Alfaro, F.; Marchandon, G.; Sanhueza, C.; Farías, L.; Trefault, N.; Marquet, P.; Molina-Montenegro, M.; Sylvander, P.; Snoeijs-Leijonmalm, P. | 2019 | Zonas Costeras | 10.1038/s41396-018-0268-9 | http://www.nature.com/articles/s41396-018-0268-9 | 316–333 | Vol: 13 | 1751-7362 | Thomson Reuters ISI (SCIE) | | English | Larger volumes of sea ice have been thawing in the Central Arctic Ocean (CAO) during the last decades than during the past 800,000 years. Brackish brine (fed by meltwater inside the ice) is an expanding sympagic habitat in summer all over the CAO. We report for the first time the structure of bacterial communities in this brine. They are composed of psychrophilic extremophiles, many of them related to phylotypes known from Arctic and Antarctic regions. Community structure displayed strong habitat segregation between brackish ice brine (IB; salinity 2.4–9.6) and immediate sub-ice seawater (SW; salinity 33.3–34.9), expressed at all taxonomic levels (class to genus), by dominant phylotypes as well as by the rare biosphere, and with specialists dominating IB and generalists SW. The dominant phylotypes in IB were related to Candidatus Aquiluna and Flavobacterium, those in SW to Balneatrix and ZD0405, and those shared between the habitats to Halomonas, Polaribacter and Shewanella. A meta-analysis for the oligotrophic CAO showed a pattern with Flavobacteriia dominating in melt ponds, Flavobacteriia and Gammaproteobacteria in solid ice cores, Flavobacteriia, Gamma- and Betaproteobacteria, and Actinobacteria in brine, and Alphaproteobacteria in SW. Based on our results, we expect that the roles of Actinobacteria and Betaproteobacteria in the CAO will increase with global warming owing to the increased production of meltwater in summer. IB contained three times more phylotypes than SW and may act as an insurance reservoir for bacterial diversity that can act as a recruitment base when environmental conditions change. |
| Summer phyto- and bacterioplankton communities during low and high productivity scenarios in the Western Antarctic Peninsula | Polar Biology | Fuentes, S.; Arroyo, J.; Rodríguez-Marconi, S.; Masotti, I.; Alarcón-Schumacher, T.; Polz, M.; Trefault, N.; De la Iglesia, R.; Díez, B. | 2019 | Zonas Costeras | 10.1007/s00300-018-2411-5 | https://link.springer.com/10.1007/s00300-018-2411-5 | 159-169 | Vol: 42 Issue: 1 | 0722-4060, 1432-2056 | Thomson Reuters ISI (SCIE) | | English | Phytoplankton blooms taking place during the warm season drive high productivity in Antarctic coastal seawaters. Important temporal and spatial variations exist in productivity patterns, indicating local constraints influencing the phototrophic community. Surface water in Chile Bay (Greenwich Island, South Shetlands) is influenced by freshwater from the melting of sea ice and surrounding glaciers; however, it is not a widely studied system. The phyto- and bacterioplankton communities in Chile Bay were studied over two consecutive summers; during a low productivity period (chlorophyll a < 0.05 mg m−3) and an ascendant phototrophic bloom (chlorophyll a up to 2.38 mg m−3). Microbial communities were analyzed by 16S rRNA—including plastidial—gene sequencing. Diatoms (mainly Thalassiosirales) were the most abundant phytoplankton, particularly during the ascendant bloom. Bacterioplankton in the low productivity period was less diverse and dominated by a few operational taxonomic units (OTUs), related to Colwellia and Pseudoalteromonas. Alpha diversity was higher during the bloom, where several Bacteroidetes taxa absent in the low productivity period were present. Network analysis indicated that phytoplankton relative abundance was correlated with bacterioplankton phylogenetic diversity and the abundance of several bacterial taxa. Hubs—the most connected OTUs in the network—were not the most abundant OTUs and included some poorly described taxa in Antarctica, such as Neptunomonas and Ekhidna. In summary, the results of this study indicate that in Antarctic Peninsula coastal waters, such as Chile Bay, higher bacterioplankton community diversity occurs during a phototrophic bloom. This is likely a result of primary production, providing a source of fresh organic matter to bacterioplankton. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. |
| Informe a las naciones: El Antropoceno en Chile: evidencias y formas de avanzar | | Gallardo, L.; Rudnick, A.; Barraza, J.; Fleming, Z.; Rojas, M.; Gayo, E.; Aguirre, C.; Farías, L.; Boisier, J.; Garreaud, R.; Barría, P.; Miranda, A.; Lara, A.; Gómez-González, S.; Arriagada, R. | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2019/06/Informe-Antropoceno-castellano.pdf | 40 | | | | | English | En el siglo XXI, el desarrollo de Chile está en juego debido a las amenazas planteadas por el Antropoceno. Esta época se caracteriza por la influencia humana sobre el sistema terrestre. Sin embargo, si se enfrenta con audacia, ofrece una oportunidad para un desarrollo sostenible. Independientemente de si hemos entrado en una nueva era geológica, el Antropoceno cuestiona nuestra forma de vivir en el planeta azul del sistema solar. O, dicho de otra manera, la forma de entender el progreso y el desarrollo. En un país con grandes desigualdades sociales, altamente vulnerable al cambio global, enfrentar este desafío es de crucial importancia y puede ofrecer nuevas oportunidades. |
| Summertime precipitation deficits in the southern Peruvian highlands since 1964 | International Journal of Climatology | Imfeld, N.; Barreto Schuler, C.; Correa Marrou, K.; Jacques‐Coper, M.; Sedlmeier, K.; Gubler, S.; Huerta, A.; Brönnimann, S. | 2019 | Zonas Costeras | 10.1002/joc.6087 | https://onlinelibrary.wiley.com/doi/abs/10.1002/joc.6087 | 4497-4513 | Vol: 39 Issue: 11 | 0899-8418 | Thomson Reuters ISI (SCIE) | | English | Precipitation deficits remain a concern to the rural population in the southern Peru-vian highlands and knowledge about their occurrence is lacking because of scarcedata availability. For mountainous regions with sparse station networks, reanalysescan provide valuable information; however, known limitations in reproducing pre-cipitation are aggravated due to unresolved topographical effects. In this study, weassess in a first step the representation of precipitation during the rainy season(January–February–March) in seven reanalysis data sets in comparison to a newlygenerated gridded precipitation data set for Peru. In a second step, we assess sum-mer precipitation deficits in Peru during the second half of the 20th century.In the reanalyses data sets, we find biases strongly influenced by the topography ofthe models and low correlations for the rainy season. Thus, reanalyses do not solvethe problem of data scarcity for this region either. Furthermore, we confirm that ElNiño is not a sufficient stratification criterion for precipitation deficits during therainy season (JFM) in the southern Peruvian highlands. Based on observationalrecords and reanalyses, a considerable fraction of inter-annual variability of precipi-tation can be explained through upper-tropospheric zonal wind anomalies. Westerlywind anomalies, often related to the warming of the troposphere during an El Niñoevent, lead to dry conditions, but not all El Niño events produce these westerly windanomalies. Atmospheric simulations indicate differences between precipitation defi-cits in central Pacific and eastern Pacific El Niño flavours, which cannot beaddressed in observations due to reduced record length: Droughts in the southernPeruvian Andes during eastern Pacific El Niño events seem to be related to a stron-ger warming in the troposphere above the central Pacific ocean, whereas this is notthe case for droughts during central Pacific El Niño events. These results, however,need to be further corroborated by model studies and palaeoclimatological research. |
| Comité Científico COP25: Chilean NDC mitigation proposal: Methodological approach and supporting ambition. Mitigation and energy working group report | | Palma-Behnke, R.; Barría, C.; Basoa, K.; Benavente, D.; Benavides, C.; Campos, B.; de la Maza, N.; Farías, L.; Gallardo, L.; García, M.; Gonzales, L.; Guarda, F.; Guzmán, R.; Jofré, A.; Mager, J.; Martínez, R.; Montedonico, M.; Morán, L.; Muñoz, L.; Osses, M.; Pica, A.; Rojas, M.; Rudnick, A.; SanMa... | 2019 | Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://comitecientifico.minciencia.gob.cl/wp-content/uploads/2021/11/The_Chilean_Potential_for_Exporting_Renewable_Energy_web.pdf | | | | | | | This paper analyses the Chilean Nationally Determined Contributions (NDC) proposal for the mitigation component. The methodological approach and the supporting ambition of a process carried out by the Chilean Government are assessed based on the scientific evidence available and local context. The analysis is developed by representatives of four ministries and a group of 21 researchers from six universities and research centers throughout the country. This exchange experience between the Government and the scientific community enables the identification of future challenges and opportunities for the Chilean transition in terms of mitigation. This process emerges from a bridging approach led by the recently assumed Minister of Science, Technology, Knowledge and Innovation under the presidency of the Government of Chile in the Conference of the Parties (COP25) for the United Nations Framework Convention on Climate Change (UNFCCC). After a description of the methodological approach, key topics that have an impact on the NDC definition are identified and analyzed. These topics include technical, economical, and socio-environmental issues along with a description of the current socio-political context in the country. Additionally, the major uncertainties that would have the highest potential to modify the results and conclusions of this work are identified. Finally, a summary with the main conclusions and recommendations is presented. The analysis framework and key aspects identified in this exercise may be of value for other countries with similar institutional contexts. |
| Validation of Cryogenic Vacuum Extraction of Pore Water from Volcanic Soils for Isotopic Analysis | Water | Rivera, D.; Gutierrez, K.; Valdivia-Cea, W.; Zambrano-Bigiarini, M.; Godoy-Faúndez, A.; Álvez, A.; Farías, L. | 2019 | Agua y Extremos; Zonas Costeras | 10.3390/w11112214 | https://www.mdpi.com/2073-4441/11/11/2214 | 2214 | Vol: 11 Issue: 11 | 2073-4441 | Thomson Reuters ISI (SCIE) | | English | Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores; and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from −1500 to −33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40–50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes. |
| Comité Científico COP25: Evidencia científica y cambio climático en Chile. Resumen para tomadores de decisiones. | | Rojas, M.; Aldunce, P.; Farías, L.; González, H.; Marquet, P.; Muñoz, J.; Palma-Behnke, R.; Stehr, A.; Vicuña, S. | 2019 | Agua y Extremos; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://comitecientifico.minciencia.gob.cl/wp-content/uploads/2021/05/Evidencia-cientifica-y-cambio-climatico-en-Chile-Resumen.pdf | 1-68 | | | | | Spanish | Los resúmenes están basados en los informes y los talleres
del Comité Científico COP25, a los que contribuyeron
investigadores de una red de más de 600 científicos de
todas las disciplinas y regiones de Chile, primordialmente de
universidades y centros de investigación académicos, pero
también de institutos públicos y privados. |
| Strongest MJO on Record Triggers Extreme Atacama Rainfall and Warmth in Antarctica | Geophysical Research Letters | Rondanelli, R.; Hatchett, B.; Rutllant, J.; Bozkurt, D.; Garreaud, R. | 2019 | Agua y Extremos; Zonas Costeras | 10.1029/2018GL081475 | https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081475 | 3482-3491 | Vol: 46 Issue: 6 | 0094-8276 | Thomson Reuters ISI (SCIE) | | English | Tropical perturbations have been shown theoretically and observationally to excite long range atmospheric responses in the form of Rossby wave teleconnections that result from the equator to pole gradient of planetary vorticity. An extreme teleconnection event occurred during March 2015 in the Southeastern Pacific. As a result, extreme high temperatures were observed in Southwestern South America and the Antarctic Peninsula simultaneously with an extreme rainfall and flood event in the hyperarid Atacama desert.%%%%%%We show that the origin of these seemingly disconnected extreme events can be traced to a Rossby wave response to the strongest Madden‐Julian Oscillation (MJO) on record in the tropical central Pacific. A barotropic wavenumber 3 to 4 perturbation with group velocity between 15 to 30 m/s is consistent with the trajectory and timing followed by the upper level anomalies radiating away from the tropics after the MJO episode. |
| Black carbon and other light-absorbing impurities in snow in the Chilean Andes | Scientific Reports | Rowe, P.; Cordero, R.; Warren, S.; Stewart, E.; Doherty, S.; Pankow, A.; Schrempf, M.; Casassa, G.; Carrasco, J.; Pizarro, J.; MacDonell, S.; Damiani, A.; Lambert, F.; Rondanelli, R.; Huneeus, N.; Fernandoy, F.; Neshyba, S. | 2019 | Ciudades Resilientes; Zonas Costeras | 10.1038/s41598-019-39312-0 | http://www.nature.com/articles/s41598-019-39312-0 | art: 4008 | Vol: 9 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | | English | Vertical profiles of black carbon (BC) and other light-absorbing impurities were measured in seasonal snow and permanent snowfields in the Chilean Andes during Austral winters 2015 and 2016, at 22 sites between latitudes 18°S and 41°S. The samples were analyzed for spectrally-resolved visible light absorption. For surface snow, the average mass mixing ratio of BC was 15 ng/g in northern Chile (18–33°S), 28 ng/g near Santiago (a major city near latitude 33°S, where urban pollution plays a significant role), and 13 ng/g in southern Chile (33–41°S). The regional average vertically-integrated loading of BC was 207 µg/m 2 in the north, 780 µg/m 2 near Santiago, and 2500 µg/m 2 in the south, where the snow season was longer and the snow was deeper. For samples collected at locations where there had been no new snowfall for a week or more, the BC concentration in surface snow was high (~10–100 ng/g) and the sub-surface snow was comparatively clean, indicating the dominance of dry deposition of BC. Mean albedo reductions due to light-absorbing impurities were 0.0150, 0.0160, and 0.0077 for snow grain radii of 100 µm for northern Chile, the region near Santiago, and southern Chile; respective mean radiative forcings for the winter months were 2.8, 1.4, and 0.6 W/m 2 . In northern Chile, our measurements indicate that light-absorption by impurities in snow was dominated by dust rather than BC. © 2019, The Author(s). |
| Comité Científico COP25: Recursos hídricos en Chile: Impactos y adaptación al cambio climático. Informe de la mesa de Agua. | | Stehr, A.; Álvarez, C.; Álvarez, P.; Arumí, J.; Baeza, C.; Barra, R.; Berroeta, C.; Castillo, Y.; Chiang, G.; Cotoras, D.; Crespo, S.; Delgado, V.; Donoso, G.; Dussaillant, A.; Ferrando, F.; Figueroa, R.; Frêne, C.; Fuster, R.; Godoy, A.; Gómez, T.; Holzapfel, E.; Huneeus, C.; Jara, M.; Little, C.; ... | 2019 | Agua y Extremos; Cambio de Uso de Suelo; Zonas Costeras | | https://www.minciencia.gob.cl/comitecientifico/documentos/mesa-agua/19.Agua-Recursos-Hidricos-Stehr.pdf | | | | | | | La comparación entre el período 1985-2015 y el período 2030-2060 indica una disminución generalizada de las precipitaciones en comparación con la media histórica, pues se proyectan disminuciones promedio de entre 5% y 15% para la zona comprendida entre las cuencas de los ríos Elqui (región de Coquimbo) y el Baker (región de Aysén). Estas proyecciones se acentuarían hacia la zona sur del país, sobre todo entre la cuenca del río Biobío y el límite sur de la región de Los Lagos (Rojas, 2012). De acuerdo con trabajos como Boisier et al. (2016), se han detectado tendencias climáticas recientes en precipitación que siguen la misma dirección proyectada hacia el futuro y que han sido además atribuidas a una manifestación temprana del cambio climático |
| The influence of temperature and pH on bacterial community composition of microbial mats in hot springs from Costa Rica | MicrobiologyOpen | Uribe‐Lorío, L.; Brenes-Guillén, L.; Hernández‐Ascencio, W.; Mora‐Amador, R.; González, G.; Ramírez‐Umaña, C.; Díez, B.; Pedrós‐Alió, C. | 2019 | Zonas Costeras | 10.1002/mbo3.893 | https://onlinelibrary.wiley.com/doi/10.1002/mbo3.893 | art: e893 | Vol: 8 Issue: 10 | 2045-8827, 2045-8827 | Thomson Reuters ISI (SCIE) | | English | We used the 16S rRNA gene pyrosequencing approach to investigate the microbial diversity and community composition in several Costa Rican hot springs alongside the latitudinal axis of the country, with a range of temperatures (37–63°C), pH (6–7.5) and other geochemical conditions. A principal component analyses of the physicochemical parameters showed the samples were separated into three geochemically distinct habitats associated with the location (North, Central, and South). Cyanobacteria and Chloroflexi comprised 93% of the classified community, the former being the most abundant phylum in all samples except for Rocas Calientes 1, (63°C, pH 6), where Chloroflexi and Deinococcus-Thermus represented 84% of the OTUs. Chloroflexi were more abundant as temperature increased. Proteobacteria, Bacteriodetes and Deinococcus-Thermus comprised 5% of the OTUs represented. Other Phyla were present in very small percentages (<1%). A LINKTREE analysis showed that the community structure of the mats was shaped primarily by pH, separating samples with pH > 6.6 from samples with pH < 6.4. Thus, both pH and temperature were relevant for community composition even within the moderate ranges of variables studied. These results provide a basis for an understanding of the physicochemical influences in moderately thermophilic microbial mats. |
| Comité Científico COP25: Lineamientos para el desarrollo de planes de adaptación: Aplicación de recursos hídricos. Informe de las mesas Adaptación y Agua | | Vicuña, S.; Aldunce, P.; Stehr, A.; Cid, F.; Rivera, A.; Alencar, K.; Álvarez, C.; Barton, J.; Berroeta, C.; Boisier, J.; Bustos, E.; Bustos, S.; Correa, T.; Cortés, S.; Cubillos, L.; De la Barrera, F.; Donoso, F.; Farías, L.; Farías, D.; Fuster, R.; Gese, P.; Godoy, A.; Guerra, L.; Guida, C.; Ibarr... | 2019 | Agua y Extremos; Zonas Costeras | | https://cdn.digital.gob.cl/filer_public/f3/56/f3566a93-a46c-49cf-a73d-86d4a807a5b5/2adaptacion-lineamientosrrhh-vicuna.pdf | | | | | | | La planificación y sus instrumentos de aplicación, como los planes de adaptación, son herramientas fundamentales para abordar los desafíos de la adaptación a distintas escalas espaciales y sectoriales. El uso real de estas herramientas aún es limitado. Su aplicación es dispar, especialmente en el contexto de la región de América Latina. Pocos países han iniciado sus procesos de desarrollo de este tipo de herramientas, y donde se ha hecho, como en Chile, existen vacíos y brechas importantes para desarrollar su potencial. A través de un proceso participativo a lo largo del año basado en talleres con la comunidad científica, se generó una propuesta de lineamientos para el diseño, implementación y seguimiento de planes de adaptación, la que además fue implementada de manera práctica en un ejercicio hipotético de desarrollo de un Plan de Adaptación al Cambio Climático (PACC) para los Recursos Hídricos. Un lineamiento relevante tiene relación con los antecedentes y el proceso de diseño del plan. El explicitar el proceso de diseño utilizado es fundamental para otorgar transparencia y, por lo tanto, validez al plan. En el trabajo de diseño resulta crítico contar con procesos participativos que permitan identificar las principales vulnerabilidades, desafíos y objetivos hacia el futuro. En el contexto de los recursos hídricos esta necesidad es más patente, por lo que se requiere un proceso de participación lo más amplio posible, pero teniendo en cuenta que no es factible —ni deseable— que se incluyan en el desarrollo del plan medidas de adaptación muy específicas en virtud de las necesidades en cada territorio. Estas medidas se deben desarrollar, por ejemplo, en el contexto de planes de acción a una escala regional. Se propone que este proceso se desarrolle al alero de las discusiones que se van a generar respecto de los lineamientos generales de la gestión de recursos hídricos en el país, y en paralelo de las gestiones que actualmente se tienen que desarrollar para resolver los desafíos de la actual megasequía |
| Greenhouse gases, nutrients and the carbonate system in the Reloncaví Fjord (Northern Chilean Patagonia): Implications on aquaculture of the mussel, Mytilus chilensis, during an episodic volcanic eruption | Science of The Total Environment | Yevenes, M.; Lagos, N.; Farías, L.; Vargas, C. | 2019 | Zonas Costeras | 10.1016/j.scitotenv.2019.03.037 | https://linkinghub.elsevier.com/retrieve/pii/S0048969719310150 | 49-61 | Vol: 669 | 0048-9697 | Thomson Reuters ISI (SCIE) | | English | This study investigates the immediate and mid-term effects of the biogeochemical variables input into the Reloncaví fjord (41°40′S; 72°23′O) as a result of the eruption of Calbuco volcano. Reloncaví is an estuarine system supporting one of the largest mussels farming production within Northern Chilean-Patagonia. Field-surveys were conducted immediately after the volcanic eruption (23–30 April 2015), one month (May 2015), and five months posterior to the event (September 2015). Water samples were collected from three stations along the fjord to determine greenhouse gases [GHG: methane (CH 4 ), nitrous oxide (N 2 O)], nutrients [NO 3 − , NO 2 − , PO 4 3− , Si(OH) 4 , sulphate (SO 4 2− )], and carbonate systems parameters [total pH (pHT), temperature, salinity, dissolved oxygen (O 2 ), and total alkalinity (AT)]. Additionally, the impact of physicochemical changes in the water column on juveniles of the produced Chilean blue mussel, Mytilus chilensis, was also studied. Following the eruption, a large phytoplankton bloom led to an increase in pH T , due to the uptake of dissolved-inorganic carbon in photic waters, potentially associated with the runoff of continental soil covered in volcanic ash. Indeed, high surface SO 4 2− and GHG were observed to be associated with river discharges. No direct evidence of the eruption was observed within the carbonate system. Notwithstanding, a vertical pattern was observed, with an undersaturation of aragonite (Ω Ar < 1) both in brackish surface (<3 m) and deep waters (>10 m), and saturated values in subsurface waters (3 to 7 m). Simultaneously, juvenile mussel shells showed maximized length and weight at 4 m depth. Results suggest a localized impact of the volcanic eruption on surface GHG, nutrients and short-term effects on the carbonate system. Optimal conditions for mussel calcification were identified within a subsurface refuge in the fjord. These specific attributes can be integrated into adaptation strategies by the mussel aquaculture industry to confront ocean acidification and changing runoff conditions. © 2019 Elsevier B.V. |
| Insight into anthropogenic forcing on coastal upwelling off south-central Chile | Elem Sci Anth | Aguirre, C.; García-Loyola, S.; Testa, G.; Silva, D.; Farías, L. | 2018 | Zonas Costeras | 10.1525/elementa.314 | https://www.elementascience.org/article/10.1525/elementa.314/ | 59 | Vol: 6 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | | English | Coastal upwelling systems off the coasts of Peru and Chile are among the most productive marine ecosystems in the world, sustaining a significant percentage of global primary production and fishery yields. Seasonal and interannual variability in these systems has been relatively well documented; however, an understanding of recent trends and the influence of climate change on marine processes such as surface cooling and primary productivity is limited. This study presents evidence that winds favorable to upwelling have increased within the southern boundary of the Humboldt Current System (35°–42°S) in recent decades. This trend is consistent with a poleward movement of the influence of the Southeast Pacific Anticyclone and resembles the spatial pattern projected by Global Circulation Models for warming scenarios. Chlorophyll a levels (from 2002 to present) determined by satellite and field-based time-series observations show a positive trend, mainly in austral spring–summer (December–January–February), potentially explained by observed increments in nutrient flux towards surface waters and photosynthetically active radiation. Both parameters appear to respond to alongshore wind stress and cloud cover in the latitudinal range of 35°S to 42°S. In addition, net annual deepening of the mixed layer depth is estimated using density and temperature profiles. Changes in this depth are associated with increasing winds and may explain cooler, more saline, and more productive surface waters, with the latter potentially causing fluctuations in dissolved oxygen and other gases, such as nitrous oxide, sensitive to changes in oxygenation. We argue that these recent changes represent, at least in part, a regional manifestation of the Anthropocene along the Chilean coast. |
| Microbial activity during a coastal phytoplankton bloom on the Western Antarctic Peninsula in late summer | FEMS Microbiology Letters | Alcamán-Arias, M.; Farías, L.; Verdugo, J.; Alarcón-Schumacher, T.; Díez, B. | 2018 | Zonas Costeras | 10.1093/femsle/fny090 | https://academic.oup.com/femsle/article/doi/10.1093/femsle/fny090/4961137 | art: fny090 | Vol: 365 Issue: 10 | 1574-6968 | Thomson Reuters ISI (SCIE) | | English | Phytoplankton biomass during the austral summer is influenced by freezing and melting cycles as well as oceanographic processes that enable nutrient redistribution in the West Antarctic Peninsula (WAP). Microbial functional capabilities, metagenomic and metatranscriptomic activities as well as inorganic 13C- and 15N-assimilation rates were studied in the surface waters of Chile Bay during two contrasting summer periods in 2014. Concentrations of Chlorophyll a (Chla) varied from 0.3 mg m−3 in February to a maximum of 2.5 mg m−3 in March, together with a decrease in nutrients; however, nutrients were never depleted. The microbial community composition remained similar throughout both sampling periods; however, microbial abundance and activity changed with Chla levels. An increased biomass of Bacillariophyta, Haptophyceae and Cryptophyceae was observed along with night-grazing activity of Dinophyceae and ciliates (Alveolates). During high Chla conditions, HCO3− uptake rates during daytime incubations increased 5-fold (>2516 nmol C L−1 d−1), and increased photosynthetic transcript numbers that were mainly associated with cryptophytes; meanwhile night time NO3− (>706 nmol N L−1 d−1) and NH4+ (41.7 nmol N L−1 d−1) uptake rates were 2- and 3-fold higher, respectively, due to activity from Alpha-/Gammaproteobacteria and Bacteroidetes (Flavobacteriia). Due to a projected acceleration in climate change in the WAP, this information is valuable for predicting the composition and functional changes in Antarctic microbial communities. |
| Diurnal Changes in Active Carbon and Nitrogen Pathways Along the Temperature Gradient in Porcelana Hot Spring Microbial Mat | Frontiers in Microbiology | Alcamán-Arias, M.; Pedrós-Alió, C.; Tamames, J.; Fernández, C.; Pérez-Pantoja, D.; Vásquez, M.; Díez, B. | 2018 | Zonas Costeras | 10.3389/fmicb.2018.02353 | https://www.frontiersin.org/article/10.3389/fmicb.2018.02353/full | art: 2353 | Vol: 9 | 1664-302X | Thomson Reuters ISI (SCIE) | | English | Composition, carbon and nitrogen uptake, and gene transcription of microbial mat communities in Porcelana neutral hot spring (Northern Chilean Patagonia) were analyzed using metagenomics, metatranscriptomics and isotopically labeled carbon ((HCO3)-C-13) and nitrogen ((NH4Cl)-N-15 and (KNO3)-N-15) assimilation rates. The microbial mat community included 31 phyla, of which only Cyanobacteria and Chloroflexi were dominant. At 58 degrees C both phyla co-occurred, with similar contributions in relative abundances in metagenomes and total transcriptional activity. At 66 degrees C, filamentous anoxygenic phototrophic Chloroflexi were >90% responsible for the total transcriptional activity recovered, while Cyanobacteria contributed most metagenomics and metatranscriptomics reads at 48 degrees C. According to such reads, phototrophy was carried out both through oxygenic photosynthesis by Cyanobacteria (mostly Mastigocladus) and anoxygenic phototrophy due mainly to Chloroflexi. Inorganic carbon assimilation through the Calvin-Benson cycle was almost exclusively due to Mastigocladus, which was the main primary producer at lower temperatures. Two other CO2 fixation pathways were active at certain times and temperatures as indicated by transcripts: 3-hydroxypropionate (3-HP) bi-cycle due to Chloroflexi and 3-hydroxypropionate-4-hydroxybutyrate (HH) cycle carried out by Thaumarchaeota. The active transcription of the genes involved in these C-fixation pathways correlated with high in situ determined carbon fixation rates. In situ measurements of ammonia assimilation and nitrogen fixation (exclusively attributed to Cyanobacteria and mostly to Mastigocladus sp.) showed these were the most important nitrogen acquisition pathways at 58 and 48 degrees C. At 66 degrees C ammonia oxidation genes were actively transcribed (mostly due to Thaumarchaeota). Reads indicated that denitrification was present as a nitrogen sink at all temperatures and that dissimilatory nitrate reduction to ammonia (DNRA) contributed very little. The combination of metagenomic and metatranscriptomic analysis with in situ assimilation rates, allowed the reconstruction of day and night carbon and nitrogen assimilation pathways together with the contribution of keystone microorganisms in this natural hot spring microbial mat. |
| Temperature modulates Fischerella thermalis ecotypes in Porcelana Hot Spring | Systematic and Applied Microbiology | Alcorta, J.; Espinoza, S.; Viver, T.; Alcamán-Arias, M.; Trefault, N.; Rosselló-Móra, R.; Díez, B. | 2018 | Zonas Costeras | 10.1016/j.syapm.2018.05.006 | https://linkinghub.elsevier.com/retrieve/pii/S0723202018302297 | 531-543 | Vol: 41 Issue: 6 | 0723-2020 | Thomson Reuters ISI (SCIE) | | English | In the Porcelana Hot Spring (Northern Patagonia), true-branching cyanobacteria are the dominant primary producers in microbial mats, and they are mainly responsible for carbon and nitrogen fixation. However, little is known about their metabolic and genomic adaptations at high temperatures. Therefore, in this study, a total of 81 Fischerella thermalis strains (also known as Mastigocladus laminosus) were isolated from mat samples in a thermal gradient between 61–46 °C. The complementary use of proteomic comparisons from these strains, and comparative genomics of F. thermalis pangenomes, suggested that at least two different ecotypes were present within these populations. MALDI-TOF MS analysis separated the strains into three clusters; two with strains obtained from mats within the upper temperature range (61 and 54 °C), and a third obtained from mats within the lower temperature range (51 and 46 °C). Both groups possessed different but synonymous nifH alleles. The main proteomic differences were associated with the abundance of photosynthesis-related proteins. Three F. thermalis metagenome assembled genomes (MAGs) were described from 66, 58 and 48 °C metagenomes. These pangenomes indicated a divergence of orthologous genes and a high abundance of exclusive genes at 66 °C. These results improved the current understanding of thermal adaptation of F. thermalis and the evolution of these thermophilic cyanobacterial species. |
| Gene fusion of heterophyletic gamma-globin genes in platyrrhine primates | Journal of Genetics | Arroyo, J.; Nery, M. | 2018 | Zonas Costeras | 10.1007/s12041-018-1039-0 | http://link.springer.com/10.1007/s12041-018-1039-0 | 1473-1478 | Vol: 97 Issue: 5 | 0022-1333, 0973-7731 | Thomson Reuters ISI (SCIE) | | English | We performed phylogenetic analyses of HBG genes to assess its origin and interspecific variation among primates. Our analyses showed variation in HBG genes copy number ranging from one to three, some of them pseudogenes. For platyrrhines HBG genes, phylogenetic reconstructions of flanking regions recovered orthologous clades with distinct topologies for 5′ and 3′ flanking regions. The 5′ region originated in the common ancestor of platyrrhines but the 3′ region had an anthropoid origin. We hypothesize that the platyrrhine HBG genes of 5′ and 3′ heterophyletic origins arose from subsequent fusions of the (earlier) platyrrhine 5′ portion and the (later) anthropoid 3′ portion. |
| Anthropogenic drying in central-southern Chile evidenced by long-term observations and climate model simulations | Elementa: Science of the Anthropocene | Boisier, J.; Alvarez-Garretón, C.; Cordero, R.; Damiani, A.; Gallardo, L.; Garreaud, R.; Lambert, F.; Ramallo, C.; Rojas, M.; Rondanelli, R. | 2018 | Agua y Extremos; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | 10.1525/elementa.328 | https://www.elementascience.org/article/10.1525/elementa.328/ | 74 | Vol: 6 Issue: 1 | 2325-1026 | Thomson Reuters ISI (SCIE) | | English | The socio-ecological sensitivity to water deficits makes Chile highly vulnerable to global change. New evidence of a multi-decadal drying trend and the impacts of a persistent drought that since 2010 has affected several regions of the country, reinforce the need for clear diagnoses of the hydro-climate changes in Chile. Based on the analysis of long-term records (50+ years) of precipitation and streamflow, we confirm a tendency toward a dryer condition in central-southern Chile (30–48°S). We describe the geographical and seasonal character of this trend, as well as the associated large-scale circulation pat- terns. When a large ensemble of climate model simulations is contrasted to observations, anthropogenic forcing appears as the leading factor of precipitation change. In addition to a drying trend driven by greenhouse gas forcing in all seasons, our results indicate that the Antarctic stratospheric ozone deple- tion has played a major role in the summer rainfall decline. Although average model results agree well with the drying trend’s seasonal character, the observed change magnitude is two to three times larger than that simulated, indicating a potential underestimation of future projections for this region. Under present-day carbon emission rates, the drying pathway in Chile will likely prevail during the next decades, although the summer signal should weaken as a result of the gradual ozone layer recovery. The trends and scenarios shown here pose substantial stress on Chilean society and its institutions, and call for urgent action regarding adaptation measures. |
| Foehn Event Triggered by an Atmospheric River Underlies Record-Setting Temperature Along Continental Antarctica | Journal of Geophysical Research: Atmospheres | Bozkurt, D.; Rondanelli, R.; Marín, J.; Garreaud, R. | 2018 | Agua y Extremos; Zonas Costeras | 10.1002/2017JD027796 | http://doi.wiley.com/10.1002/2017JD027796 | 3871-3892 | Vol: 123 Issue: 8 | 2169-897X | Thomson Reuters ISI (SCIE) | | English | A record‐setting temperature of 17.5°C occurred on 24 March 2015 at the Esperanza station located near the northern tip of the Antarctic Peninsula (AP). We studied the event using surface station data, satellite imagery, reanalysis data, and numerical simulations. The Moderate Resolution Imaging Spectroradiometer Antarctic Ice Shelf Image Archive provides clear evidence for disintegration and advection of sea ice, as well as the formation of melt ponds on the ice sheet surface at the base of the AP mountain range. A deep low‐pressure center over the Amundsen‐Bellingshausen Sea and a blocking ridge over the southeast Pacific provided favorable conditions for the development of an atmospheric river with a northwest‐southeast orientation, directing warm and moist air toward the AP, and triggering a widespread foehn episode. A control simulation using a regional climate model shows the existence of local topographically induced warming along the northern tip of the AP (∼60% of the full temperature signal) and the central part of the eastern AP (>90% of the full temperature signal) with respect to a simulation without topography. These modeling results suggest that more than half of the warming experienced at Esperanza can be attributed to the foehn effect (a local process), rather than to the large‐scale advection of warm air from the midlatitudes. Nevertheless, the local foehn effect also has a large‐scale advection component, since the atmospheric river provides water vapor for orographic precipitation enhancement and latent heat release, which makes it difficult to completely disentangle the role of local versus large‐scale processes in explaining the extreme event. |
| Distribution of dissolved methane and nitrous oxide in Chilean coastal systems of the Magellanic Sub-Antarctic region (50°–55°S) | Estuarine, Coastal and Shelf Science | Farías, L.; Bello, E.; Arancibia, G.; Fernandez, J. | 2018 | Zonas Costeras | 10.1016/j.ecss.2018.10.020 | https://linkinghub.elsevier.com/retrieve/pii/S0272771418304785 | 229-240 | Vol: 215 | 0272-7714 | Thomson Reuters ISI (SCIE) | | English | Nitrous oxide (N2O) and methane (CH4) are greenhouse gases and active in the depletion of the ozone layer. These gases, originating from both anthropogenic and natural sources, are mainly released to the atmosphere from coastal areas, including continental shelves, estuaries and fjords. Surface distribution of dissolved N2O and CH4 during the austral spring were described within the Magellanic Sub-Antarctic region (50–55°S, Chile) with a coastal area that has a complex system of fjords, channels, gulf and, bays. A narrow range of N2O concentrations were observed from under-saturations (∼65%), as result of freshwater/glacial flow into fjord heads, to slight super-saturations (∼120–150%) in fjord mouths and adjacent marine zones. One exception was Otway Sound, where a penguin colony is situated, with N2O levels of up to 218%. In contrast, CH4 concentrations presented a wide range of saturations between 47.9% and 483%, with a spatial distribution that mainly corresponded to the type of hydrographic/geomorphologic basin; in the southern Patagonian Andes (mostly covered by the southern Ice Fields) CH4 levels varied between 65 and 80% in the marine area, and 180% saturation in the channels and fjords; whereas in the southern Patagonian tableland (Magellan Strait) higher CH4 concentrations, up to 483% saturation, were observed apparently associated with continental inputs (peatland and tundra vegetation). N2O concentrations were positively correlated with salinity and nutrients, indicating that the majority of N2O and nutrients (except silicate) originated from the Sub-Antarctic Water Mass (SAAW), which mixes with N2O-depleated freshwater. However, CH4 concentrations did not correlate with any oceanographic variables, suggesting that they originate from local marine/terrestrial interactions. The Magellanic Sub-Antarctic region acts as a modest source of N2O and CH4, to the atmosphere with effluxes of 6.20 ± 10.13 and 16.88 ± 27.04 μmol m−2 d−1 respectively. Due to climate change and a growth in anthropogenic activities such as salmon farming, future emissions of N2O and CH4 within this remote region remain uncertain. |
| Active Crossfire Between Cyanobacteria and Cyanophages in Phototrophic Mat Communities Within Hot Springs | Frontiers in Microbiology | Guajardo-Leiva, S.; Pedrós-Alió, C.; Salgado, O.; Pinto, F.; Díez, B. | 2018 | Zonas Costeras | 10.3389/fmicb.2018.02039 | https://www.frontiersin.org/article/10.3389/fmicb.2018.02039/full | art: 2039 | Vol: 9 | 1664-302X | Thomson Reuters ISI (SCIE) | | English | Cyanophages are viruses with a wide distribution in aquatic ecosystems, that specifically infect Cyanobacteria. These viruses can be readily isolated from marine and fresh waters environments; however, their presence in cosmopolitan thermophilic phototrophic mats remains largely unknown. This study investigates the morphological diversity (TEM), taxonomic composition (metagenomics), and active infectivity (metatranscriptomics) of viral communities over a thermal gradient in hot spring phototrophic mats from Northern Patagonia (Chile). The mats were dominated (up to 53%) by cosmopolitan thermophilic filamentous true-branching cyanobacteria from the genus Mastigocladus, the associated viral community was predominantly composed of Caudovirales (70%), with most of the active infections driven by cyanophages (up to 90% of Caudovirales transcripts). Metagenomic assembly lead to the first full genome description of a T7-like Thermophilic Cyanophage recovered from a hot spring (Porcelana Hot Spring, Chile), with a temperature of 58°C (TC-CHP58). This could potentially represent a world-wide thermophilic lineage of podoviruses that infect cyanobacteria. In the hot spring, TC-CHP58 was active over a temperature gradient from 48 to 66°C, showing a high population variability represented by 1979 single nucleotide variants (SNVs). TC-CHP58 was associated to the Mastigocladus spp. by CRISPR spacers. Marked differences in metagenomic CRISPR loci number and spacers diversity, as well as SNVs, in the TC-CHP58 proto-spacers at different temperatures, reinforce the theory of co-evolution between natural virus populations and cyanobacterial hosts. Considering the importance of cyanobacteria in hot spring biogeochemical cycles, the description of this new cyanopodovirus lineage may have global implications for the functioning of these extreme ecosystems. |
| The influence of river discharge on nutrient export and phytoplankton biomass off the Central Chile coast (33º-37ºS). Seasonal cycle and interannual variability | Frontier in Marine Science | Masotti, I.; Aparicio-Rizzo, P.; Yevenes, M.; Garreaud, R.; Farías, L. | 2018 | Zonas Costeras | 10.3389/fmars.2018.00423 | https://doi.org/10.3389/fmars.2018.00423 | 423 | Vol: 5 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | Using in situ hydro-chemical data and MODIS-SeaWiFS ocean color images as a proxy of river plumes and phytoplankton biomass from 2000 to 2014, this study documents the temporal co-variability of river discharge, plume area, nitrate and phosphate export and phytoplankton biomass in the coastal waters off Central Chile (33º-37ºS). Five major rivers (Maipo, Mataquito, Maule, Itata and Biobío) drain into this region with annual mean discharge ranging from 120 to 1000 m3 s-1. River discharge and coastal plume area present a marked seasonal cycle, reaching maximum values during the winter rainy season (June-September). Export of riverine nutrients also peaks in winter, leading to an increase in phytoplankton biomass within the plumes that can be twice larger than the background values in coastal areas away from the river mouths. Wintertime river discharge, plume area and nutrient export are also correlated at interannual time scales. During a recent extended dry period (2010-2014), river discharges, plume areas and nutrient export clearly decreased by about 50% compared to historical values, reducing significantly the size of the chlorophyll pool within plumes off Central Chile during winter. The potential impacts of droughts are discussed in terms of coastal ecology and primary production, a highly relevant issue considering the projections of a dry climate over Central Chile in the future. Systematic evidence of mega-drought effects upon coastal productivity still does not exist, but it remains a priority to further investigate and quantify these impacts. |
| Informe final Océano y NDC | | Moraga Sariego, P.; Farías, L.; Delgado, V.; Urquiza, A.; Morales, B. | 2018 | Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/wp-content/uploads/2018/07/informe_oceano_NDC.pdf | | | | | | | El Acuerdo de París sobre Cambio Climático establece como obligación para los países firmantes presentar una Contribución Nacionalmente Determinada (Nationally Determined Contributions, o NDCs) y revisarla cada cinco años. Es por esta razón que la NDC de Chile está siendo sometida a un proceso de revisión con el propósito de identificar oportunidades de actualización y refinamiento de su primera versión. El Ministerio de Relaciones Exteriores, responsable de llevar a cabo esta actualización, se ha propuesto incorporar la protección y conservación del océano en dicho proceso, en conformidad con los objetivos planteados en la declaración “Because the Ocean”, así como en el “Ocean Pathway Platform” lanzado por la Presidencia de la COP23. Para ello se estableció un marco de colaboración técnica entre el Ministerio de Relaciones Exteriores, el Centro de Ciencia del Clima y la Resiliencia (CR)2 y el Centro de Derecho Ambiental (CDA) de la Facultad de Derecho de la Universidad de Chile, entre los meses de diciembre de 2017 y abril de 2018, con el objeto de generar un informe sobre la incorporación del océano en la NDC de Chile, a la luz de la agenda oceánica y en concordancia con los Objetivos de Desarrollo Sustentable (ODS). |
| Assessment of methane and carbon dioxide emissions in two sub-basins of a small acidic bog lake artificially divided 30 years ago | Freshwater Biology | Sepulveda-Jauregui, A.; Martinez-Cruz, K.; Lau, M.; Casper, P. | 2018 | Zonas Costeras | 10.1111/fwb.13182 | http://doi.wiley.com/10.1111/fwb.13182 | 1534-1549 | Vol: 63 Issue: 12 | 0046-5070 | Thomson Reuters ISI (SCIE) | | English | Although lakes are important sources of methane (CH4) and carbon dioxide (CO2) to the atmosphere contributing to global warming, their CH4 and CO2 emissions are rarely assessed. In particular, increasing inputs of terrestrial dissolved organic carbon (DOC) may affect gas dynamics and alter seasonal changes in gas production. Here, we analysed variations in CH4 and CO2 dynamics in sub-basins of an acidic bog lake, which was artificially divided into four quarters three decades ago, leading to divergence in water chemistry and biology. In the divided lake, only the south-west basin (SW) received DOC inputs from an adjacent peat bog, while the north-east basin (NE) was hydrologically disconnected. A year-long determination of CH4 and CO2 production and emission patterns in the two contrasting basins exposed the indirect mechanisms by which DOC supply exercised control on greenhouse gas dynamics in this shallow lake. In both basins, dissolved CH4 was negatively correlated with dissolved oxygen (O2) through the water column, suggesting that aerobic methanotrophy is an important regulator of CH4 emissions in this lake. In contrast, the amount of CO2 stored in oxic and anoxic layers was not significantly different between the basins, suggesting that O2 is not the most important driver of dissolved CO2. Estimated total CH4 and CO2 emissions were 2.1 and 1.7 times lower in the NE basin than in the SW basin, with major CH4 and CO2 emissions occurring during the fall turnover. The differences in CH4 and CO2 emissions suggest that the hydro-physical properties, namely seasonal temperature, the duration of stratification and O2 availability, are the main drivers of CH4 and CO2 emissions to the atmosphere from small shallow lakes under the influence of DOC inputs under global warming pressure. |
| Temporal Variability in Net Primary Production in an Upwelling Area off Central Chile (36°S) | Frontiers in Marine Science | Testa, G.; Masotti, I.; Farías, L. | 2018 | Zonas Costeras | 10.3389/fmars.2018.00179 | https://www.frontiersin.org/article/10.3389/fmars.2018.00179/full | art: 179 | Vol: 5 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | The temporal variability of Net Primary Production (NPP) off central Chile (36°S, 73°W), an area subjected to seasonal coastal upwelling, was analyzed using monthly in situ 13C incubations within the photic zone, along with bio-oceanographic variables from a fixed time series station; and satellite NPP estimations (NPPE) from the Vertically Generalized Production Model between 2006 and 2015. NPP and NPPE rates varied from 0.03 to 18.29 and from 0.45 to 9.07 g C m−2 d−1, respectively. Both rates were fairly well correlated with each other (r2 = 0.61), but when these data were separated into two periods, higher r2 value was found during winter (r2 = 0.70) with respect to the rest of the year (r2 = 0.24); the latter correlation was partially due to increased weekly NPPE variability during active and relaxed upwelling events. NPP rates along with other biophysical variables allowed for a division of the annual cycle into three distinct periods: September to January (high productivity, mean integrated NPP rates of 4.0 g C m−2 d−1), February to March (intermediate productivity, mean integrated NPP rates of 1.4 g C m−2 d−1), and May to August (basal level, mean integrated NPP rates of 0.5 g C m−2 d−1). NPP appeared to be partially controlled by nutrient inputs, either from upwelling (September-April) and river discharge (May-August), maintaining high NPP rates throughout the entire year, with an annual mean NPP rate of 1.1 kg C m−2 yr−1. In this region, El Niño Southern Oscillation events did not appear to impact the NPP interannual variability. |
| AOT Retrieval Procedure for Distributed Measurements With Low-Cost Sun Photometers: AOT RETRIEVAL METHOD FOR SUN PHOTOMETERS | Journal of Geophysical Research: Atmospheres | Toledo, F.; Garrido, C.; Díaz, M.; Rondanelli, R.; Jorquera, S.; Valdivieso, P. | 2018 | Zonas Costeras | 10.1002/2017JD027309 | http://doi.wiley.com/10.1002/2017JD027309 | 1113-1131 | Vol: 123 Issue: 2 | 2169-897X | Thomson Reuters ISI (SCIE) | | English | We propose a new application of inexpensive light-emitting diode (LED)-based Sun photometers, consisting of measuring the aerosol optical thickness (AOT) with high resolution within metropolitan scales. Previously, these instruments have been used at continental scales by the GLOBE program, but this extension is already covered by more expensive and higher-precision instruments of the AERONET global network. For this we built an open source two-channeled LED-based Sun photometer based on previous developments, with improvements in the hardware, software, and modifications on the calibration procedure. Among these we highlight the use of MODTRAN to characterize the effect introduced by using LED sensors in the AOT retrieval, an open design available for the scientific community and a calibration procedure that takes advantage of a CIMEL Sun photometer located within the city, enables the intercomparison of several LED Sun photometers with a common reference. We estimated the root-mean-square error in the AOT retrieved by the prototypes as 0.006 at the 564 nm and 0.009 at the 408 nm. This error is way under the magnitude of the AOT daily cycle variability measured by us in our campaigns, even for distances closer than 15 km. In addition to inner city campaigns, we also show aerosol-tracing applications by measuring AOT variations from the city of Santiago to the Andes glaciers. Measuring AOT at high spatial resolution in urban areas can improve our understanding of urban scale aerosol circulation, providing information for solar energy planning, health policies, and climatological studies, among others. |
| Toward High-Resolution Vertical Measurements of Dissolved Greenhouse Gases (Nitrous Oxide and Methane) and Nutrients in the Eastern South Pacific | Frontiers in Marine Science | Troncoso, M.; Garcia, G.; Verdugo, J.; Farías, L. | 2018 | Zonas Costeras | 10.3389/fmars.2018.00148 | https://www.frontiersin.org/articles/10.3389/fmars.2018.00148/full | art: 148 | Vol: 5 | 2296-7745 | Thomson Reuters ISI (SCIE) | | English | In this study, in situ, real-time and high-resolution vertical measurements of dissolved greenhouse gases (GHGs) such as nitrous oxide (N2O) and methane (CH4) and nutrients are reported for the eastern South Pacific (ESP); a region with marked zonal gradients, ranging from highly productive and suboxic conditions in coastal upwelling systems to oligotrophic and oxygenated conditions in the subtropical gyre. Four high-resolution vertical profiles for gases (N2O and CH4) and nutrients (NO−3 and PO3−4) were measured using a Pumped Profiling System (PPS), connected with a liquid degassing membrane coupled with Cavity Ring-Down Spectroscopy (CRDS) and a nutrient auto-analyzer, respectively. The membrane-CRDS system maintains a linear response over a wide range of gas concentrations, detecting N2O and CH4 levels as low as 0.0774 ± 0.0004 and 0.1011 ± 0.001 ppm, respectively. Continuous profiles for gases and nutrients were similar to those reported throughout the ESP, with pronounced N2O and CH4 peaks at the upper oxycline and at the base of the euphotic zone and pycnocline, respectively, in the coastal zone; but almost constant depth profiles in the subtropical gyre. Additionally, other vertical gas and nutrient structures were observed using continuous sampling, which would not have been detected by discrete sampling. Our results demonstrate that continuous measurements can be a potentially useful methodology for future GHGs cycle studies. |
| Seasonal drought effects on the water quality of the Biobío River, Central Chile | Environmental Science and Pollution Research | Yevenes, M.; Figueroa, R.; Parra, O. | 2018 | Zonas Costeras | 10.1007/s11356-018-1415-6 | http://link.springer.com/10.1007/s11356-018-1415-6 | 13844-13856 | Vol: 25 Issue: 14 | 0944-1344, 1614-7499 | Thomson Reuters ISI (SCIE) | | English | Quantifying the effect of droughts on ecosystem functions is essential to the development of coastal zone and river management under a changing climate. It is widely acknowledged that climate change is increasing the frequency and intensity of droughts, which can affect important ecosystem services, such as the regional supply of clean water. Very little is understood about how droughts affect the water quality of Chilean high flow rivers. This paper intends to investigate the effect of an, recently identified, unprecedented drought in Chile (2010–2015), on the Biobío River water quality, (36°45′–38°49′ S and 71°00′–73°20′ W), Central Chile. This river is one of the largest Chilean rivers and it provides abundant freshwater. Water quality (water temperature, pH, dissolved oxygen, electrical conductivity, biological oxygen demand, total suspended solids, chloride, sodium, nutrients, and trace metals), during the drought (2010–2015), was compared with a pre-drought period (2000–2009) over two reaches (upstream and downstream) of the river. Multivariate analysis and seasonal Mann-Kendall trend analyses and a Theil-Sen estimator were employed to analyze trends and slopes of the reaches. Results indicated a significant decreased trend in total suspended solids and a slightly increasing trend in water temperature and EC, major ions, and trace metals (chrome, lead, iron, and cobalt), mainly in summer and autumn during the drought. The reduced variability upstream suggested that nutrient and metal concentrations were more constant than downstream. The results evidenced, due to the close relationship between river discharge and water quality, a slightly decline of the water quality downstream of the Biobío River during drought period, which could be attenuated in a post-drought period. These results displayed that water quality is vulnerable to reductions in flow, through historical and emerging solutes/contaminants and induced pH mobilization. Consequently, seasonal changes and a progressive reduction of river flow affect the ecosystem functionality in this key Chilean river. The outcomes from this research can be used to improve how low flow conditions and the effects of a reduction in the river volume and discharge are assessed, which is the case under the scenario of more frequent drought periods. |
| Memoria institucional 2013 - 2017 | | | 2017 | Agua y Extremos; Cambio de Uso de Suelo; Ciudades Resilientes; Gobernanza e Interfaz Ciencia y Política; Zonas Costeras | | https://www.cr2.cl/memoria-institucional-cr2-2013-2017/ | | | | | | | |
| Vertical segregation among pathways mediating nitrogen loss (N2 and N2O production) across the oxygen gradient in a coastal upwelling ecosystem | Biogeosciences | Galán, A.; Thamdrup, B.; Saldías, G.; Farías, L. | 2017 | Zonas Costeras | 10.5194/bg-14-4795-2017 | https://www.biogeosciences.net/14/4795/2017/ | 4795-4813 | Vol: 14 Issue: 20 | 1726-4189 | Thomson Reuters ISI (SCIE) | | English | The upwelling system off central Chile (36.5 S) is seasonally subjected to oxygen (O2)-deficient waters, with a strong vertical gradient in O2 (from oxic to anoxic conditions) that spans a few metres (30-50€m interval) over the shelf. This condition inhibits and/or stimulates processes involved in nitrogen (N) removal (e.g. anammox, denitrification, and nitrification). During austral spring (September 2013) and summer (January 2014), the main pathways involved in N loss and its speciation, in the form of N2 and/or N2O, were studied using 15N-tracer incubations, inhibitor assays, and the natural abundance of nitrate isotopes along with hydrographic information. Incubations were developed using water retrieved from the oxycline (25€m depth) and bottom waters (85€m depth) over the continental shelf off Concepción, Chile. Results of 15N-labelled incubations revealed higher N removal activity during the austral summer, with denitrification as the dominant N2-producing pathway, which occurred together with anammox at all times. Interestingly, in both spring and summer maximum potential N removal rates were observed in the oxycline, where a greater availability of oxygen was observed (maximum O2 fluctuation between 270 and 40€μmol€L'1) relative to the hypoxic bottom waters ( < €20€μmol€O2€L'1). Different pathways were responsible for N2O produced in the oxycline and bottom waters, with ammonium oxidation and dissimilatory nitrite reduction, respectively, as the main source processes. Ammonium produced by dissimilatory nitrite reduction to ammonium (DNiRA) could sustain both anammox and nitrification rates, including the ammonium utilized for N2O production. The temporal and vertical variability of /15N-NO3' confirms that multiple N-cycling processes are modulating the isotopic nitrate composition over the shelf off central Chile during spring and summer. N removal processes in this coastal system appear to be related to the availability and distribution of oxygen and particles, which are a source of organic matter and the fuel for the production of other electron donors (i.e. ammonium) and acceptors (i.e. nitrate and nitrite) after its remineralization. These results highlight the links between several pathways involved in N loss. They also establish that different mechanisms supported by alternative N substrates are responsible for substantial accumulation of N2O, which are frequently observed as hotspots in the oxycline and bottom waters. Considering the extreme variation in oxygen observed in several coastal upwelling systems, these findings could help to understand the ecological and biogeochemical implications due to global warming where intensification and/or expansion of the oceanic OMZs is projected. |
| Plankton composition, biomass, phylogeny and toxin genes in Lake Big Momela, Tanzania | African Journal of Aquatic Science | Hamisi, M.; Lugomela, C.; Lyimo, T.; Bergman, B.; Díez, B. | 2017 | Zonas Costeras | 10.2989/16085914.2017.1334621 | https://www.tandfonline.com/doi/full/10.2989/16085914.2017.1334621 | 109-121 | Vol: 42 Issue: 2 | 1608-5914, 1727-9364 | Thomson Reuters ISI (SCIE) | | English | Lake Big Momela, one of the East African soda lakes in Northern Tanzania characterised by highly saline-alkaline conditions, making them inhospitable to a range of organisms, although supporting massive growths of some adapted planktonic microorganisms that serve as food for birds, such as Lesser Flamingo. The temporal dynamics of plankton, with an emphasis on cyanobacteria, were examined in 2007 using morphological traits and ribosomal genetic markers (16S and 18S rRNA). Cyanobacterial genes encoding for hepatotoxins (mcyE and ndaF) were also screened. Rotifers and copepods dominated the zooplankton, whereas cyanobacteria, such as Anabaenopsis elenkinii and Arthrospira fusiformis dominated the phytoplankton community, and these being related to representatives in other East African soda lakes. The cyanobacteria community also showed distinct seasonal patterns influenced by environmental parameters, mainly salinity, pH and nitrate. Significant positive correlations were found between phytoplankton abundance and nitrate concentrations (r = 0.617, p = 0.033). No signals of the hepatotoxin synthetase genes mcyE and ndaF were retrieved from cyanobacteria during the whole year. In general, our data illustrate the presence of rich planktonic communities, including some unique and potentially endemic cyanobacteria. |
| A solar radiation database for Chile | Scientific Reports | Molina, A.; Falvey, M.; Rondanelli, R. | 2017 | Zonas Costeras | 10.1038/s41598-017-13761-x | http://www.nature.com/articles/s41598-017-13761-x | art14823 | Vol: 7 Issue: 1 | 2045-2322 | Thomson Reuters ISI (SCIE) | | English | Chile hosts some of the sunniest places on earth, which has led to a growing solar energy industry in recent years. However, the lack of high resolution measurements of solar irradiance becomes a critical obstacle for both financing and design of solar installations. Besides the Atacama Desert, Chile displays a large array of "solar climates" due to large latitude and altitude variations, and so provides a useful testbed for the development of solar irradiance maps. Here a new public database for surface solar irradiance over Chile is presented. This database includes hourly irradiance from 2004 to 2016 at 90 m horizontal resolution over continental Chile. Our results are based on global reanalysis data to force a radiative transfer model for clear sky solar irradiance and an empirical model based on geostationary satellite data for cloudy conditions. The results have been validated using 140 surface solar irradiance stations throughout the country. Model mean percentage error in hourly time series of global horizontal irradiance is only 0.73%, considering both clear and cloudy days. The simplicity and accuracy of the model over a wide range of solar conditions provides confidence that the model can be easily generalized to other regions of the world. |
| Implementation of methane cycling for deep-time global warming simulations with the DCESS Earth system model (version 1.2) | Geoscientific Model Development | Shaffer, G.; Fernández Villanueva, E.; Rondanelli, R.; Pedersen, J.; Olsen, S.; Huber, M. | 2017 | Zonas Costeras | 10.5194/gmd-10-4081-2017 | https://www.geosci-model-dev.net/10/4081/2017/ | 4081-4103 | Vol: 10 Issue: 11 | 1991-9603 | Thomson Reuters ISI (SCIE) | | English | Geological records reveal a number of ancient, large and rapid negative excursions of the carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth system over a short duration. These injections may have forced strong global warming events, sometimes accompanied by mass extinctions such as the Triassic-Jurassic and end-Permian extinctions 201 and 252 million years ago, respectively. In many cases, evidence points to methane as the dominant form of injected carbon, whether as thermogenic methane formed by magma intrusions through overlying carbon-rich sediment or from warming-induced dissociation of methane hydrate, a solid compound of methane and water found in ocean sediments. As a consequence of the ubiquity and importance of methane in major Earth events, Earth system models for addressing such events should include a comprehensive treatment of methane cycling but such a treatment has often been lacking. Here we implement methane cycling in the Danish Center for Earth System Science (DCESS) model, a simplified but well-tested Earth system model of intermediate complexity. We use a generic methane input function that allows variation in input type, size, timescale and ocean–atmosphere partition. To be able to treat such massive inputs more correctly, we extend the model to deal with ocean suboxic/anoxic conditions and with radiative forcing and methane lifetimes appropriate for high atmospheric methane concentrations. With this new model version, we carried out an extensive set of simulations for methane inputs of various sizes, timescales and ocean–atmosphere partitions to probe model behavior. We find that larger methane inputs over shorter timescales with more methane dissolving in the ocean lead to ever-increasing ocean anoxia with consequences for ocean life and global carbon cycling. Greater methane input directly to the atmosphere leads to more warming and, for example, greater carbon dioxide release from land soils. Analysis of synthetic sediment cores from the simulations provides guidelines for the interpretation of real sediment cores spanning the warming events. With this improved DCESS model version and paleo-reconstructions, we are now better armed to gauge the amounts, types, timescales and locations of methane injections driving specific, observed deep-time, global warming events. |
| SDR Cloud Radar development with reused radio telescope components | | Toledo, F.; Rodriguez, R.; Rondanelli, R.; Aguirre, R.; Diaz, M. | 2017 | Zonas Costeras | 10.1109/GRSS-CHILE.2017.7996016 | http://ieeexplore.ieee.org/document/7996016/ | 1-5 | | | | | English | The ongoing implementation of a fog observatory in a coastal fog forest in northern Chile is expected to provide valuable information to improve our comprehension of these ecosystems alongside retrieving valuable data to fog scientists. Observing this opportunity and the increase on radio astronomy instrumental it is proposed to develop a low-cost Cloud Radar reutilizing obsolete but operative radio telescope components and software defined radios for modulation. Only preliminary tests have been conducted so far to test the viability of this approach. These tests show that it is in fact possible to build an emitter and receiver operating at 35 GHz using radio telescope components as a Radio Frequency front-end, and that the detected echo coming from the signal is affected by the presence of liquid water droplets in the air. Further development is being carried on the prototype to enable the detection of fog droplets in the boundary layer up to 2 km of height. |
