Publicaciones / Papers

1. Publicaciones en Revistas Internacionales:

Línea de InvestigaciónAñoAutoresTítuloRevistaDOIAccesoAbstractPáginasNúmeroVolumen
Servicios Ecosistémicos2013Delgado-Baquerizo, M., Maestre, F. T., Gallardo, A., Bowker, M. A., Wallenstein, M. D., Quero, J. L., Gómez-González, S., … Zaady, E. Decoupling of soil nutrient cycles as a function of aridity in global drylandsNature10.1038/nature12670 biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems1. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes1, 2, 3, 4, 5. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability6, 7, 8. The increase in aridity predicted for the twenty-first century in many drylands worldwide9, 10, 11 may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients12, 13, 14. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition12, 13, 14. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.672-6767473502
Modelación y Sistemas de Observación2013Eby, M., Weaver, A. J., Alexander, K., Zickfeld, K., Abe-Ouchi, A., Cimatoribus, A. A., Shaffer, G., … Zhao, F.Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexityClim. Past10.5194/cp-9-1111-2013 historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20th century trends in surface air temperature and carbon uptake are reasonably well simulated when compared to observed trends. Land carbon fluxes show much more variation between models than ocean carbon fluxes, and recent land fluxes appear to be slightly underestimated. It is possible that recent modelled climate trends or climate–carbon feedbacks are overestimated resulting in too much land carbon loss or that carbon uptake due to CO2 and/or nitrogen fertilization is underestimated. Several one thousand year long, idealized, 2 × and 4 × CO2 experiments are used to quantify standard model characteristics, including transient and equilibrium climate sensitivities, and climate–carbon feedbacks. The values from EMICs generally fall within the range given by general circulation models. Seven additional historical simulations, each including a single specified forcing, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows a non-linear interaction between land-use change and CO2 forcings for some models. Finally, the preindustrial portions of the last millennium simulations are used to assess historical model carbon-climate feedbacks. Given the specified forcing, there is a tendency for the EMICs to underestimate the drop in surface air temperature and CO2 between the Medieval Climate Anomaly and the Little Ice Age estimated from palaeoclimate reconstructions. This in turn could be a result of unforced variability within the climate system, uncertainty in the reconstructions of temperature and CO2, errors in the reconstructions of forcing used to drive the models, or the incomplete representation of certain processes within the models. Given the forcing datasets used in this study, the models calculate significant land-use emissions over the pre-industrial period. This implies that land-use emissions might need to be taken into account, when making estimates of climate–carbon feedbacks from palaeoclimate reconstructions.1111-114039
Dinámica del Clima2013Flores, F., Garreaud, R., & Muñoz, R. C. CFD simulations of turbulent buoyant atmospheric flows over complex geometry: Solver development in OpenFOAMComputers & Fluids10.1016/j.compfluid.2013.04.029 paper, first of a two-part work, presents an overview of the development of a computational fluid dynamics (CFD) solver in OpenFOAM platform to simulate the internal ventilation regime within an open pit including the effects of developed turbulence, buoyancy and stratification. To incorporate the effect of stratification in the simulations we have chosen a formulation that includes density as a variable in the system of equations, thus facilitating further study of buoyant flows. Given the importance of turbulence in this type of large-scale flows we have used Large Eddy Simulation (LES) to incorporate it in the calculation, using a Detached Eddy Simulation (DES) approach to solve the flow near walls. Specific initial and boundary conditions were defined. The results presented in this paper, including several tests of the solver where we compared our results with experimental or numerical data, have demonstrated the validity of using OpenFOAM to study this type of complex multiphysics problems. Especially advantageous in this regard are the flexibility provided by the modular structure of the code, the possibility of defining specific boundary and initial conditions for each case, and the ability of generating detailed meshes of complex geometries. Also we probed the benefits of using a DES approach, allowing us to solve developed turbulence and the interaction of the flow with detailed geometry. A second paper associated to this work will expose the application of the solver to large open pit mines, simulating the particular case of Chuquicamata, one of the largest open pit mines in the world, located in northern Chile.1-1382
Dinámica del Clima; Modelación y Sistemas de Observación2012Garreaud, R., Lopez, P., Minvielle, M., & Rojas, M. Large-Scale Control on the Patagonian ClimateJournal of Climate10.1175/JCLI-D-12-00001.1, located in southern South America, is a vast and remote region holding a rich variety of past environmental records but a small number of meteorological stations. Precipitation over this region is mostly produced by disturbances embedded in the westerly flow and is strongly modified by the austral Andes. Uplift on the windward side leads to hyperhumid conditions along the Pacific coast and the western slope of the Andes; in contrast, downslope subsidence dries the eastern plains leading to arid, highly evaporative conditions.The authors investigate the dependence of Patagonia’s local climate (precipitation and near-surface air temperature) year-to-year variability on large-scale circulation anomalies using results from a 30-yr-long high-resolution numerical simulation. Variations of the low-level zonal wind account for a large fraction of the rainfall variability at synoptic and interannual time scales. Zonal wind also controls the amplitude of the air temperature annual cycle by changing the intensity of the seasonally varying temperature advection.The main modes of year-to-year variability of the zonal flow over southern South America are also investigated. Year round there is a dipole between mid- and high latitudes. The node separating wind anomalies of opposite sign migrates through the seasons, leading to a dipole over Patagonia during austral summer and a monopole during winter. Reanalysis data also suggests that westerly flow has mostly decreased over north-central Patagonia during the last four decades, causing a drying trend to the west of the Andes, but a modest increase is exhibited over the southern tip of the continent.215-230126
Modelación y Sistemas de Observación2012Glasow, R. von, Jickells, T. D., Baklanov, A., Carmichael, G. R., Church, T. M., Gallardo, L., … Zhu, T. Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine EcosystemsAMBIO10.1007/s13280-012-0343-9 are not only important drivers for socio-economic development but also sources of environmental challenges. Many megacities and large urban agglomerations are located in the coastal zone where land, atmosphere, and ocean meet, posing multiple environmental challenges which we consider here. The atmospheric flow around megacities is complicated by urban heat island effects and topographic flows and sea breezes and influences air pollution and human health. The outflow of polluted air over the ocean perturbs biogeochemical processes. Contaminant inputs can damage downstream coastal zone ecosystem function and resources including fisheries, induce harmful algal blooms and feedback to the atmosphere via marine emissions. The scale of influence of megacities in the coastal zone is hundreds to thousands of kilometers in the atmosphere and tens to hundreds of kilometers in the ocean. We list research needs to further our understanding of coastal megacities with the ultimate aim to improve their environmental management.13-28142
Modelación y Sistemas de Observación2013Joos, F., Roth, R., Fuglestvedt, J. S., Peters, G. P., Enting, I. G., von Bloh, W., Shaffer, G., … Weaver, A. J. Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: a multi-model analysisAtmos. Chem. Phys.10.5194/acp-13-2793-2013 responses of carbon dioxide (CO2) and other climate variables to an emission pulse of CO2 into the atmosphere are often used to compute the Global Warming Potential (GWP) and Global Temperature change Potential (GTP), to characterize the response timescales of Earth System models, and to build reduced-form models. In this carbon cycle-climate model intercomparison project, which spans the full model hierarchy, we quantify responses to emission pulses of different magnitudes injected under different conditions. The CO2 response shows the known rapid decline in the first few decades followed by a millennium-scale tail. For a 100 Gt-C emission pulse added to a constant CO2 concentration of 389 ppm, 25 ± 9% is still found in the atmosphere after 1000 yr; the ocean has absorbed 59 ± 12% and the land the remainder (16 ± 14%). The response in global mean surface air temperature is an increase by 0.20 ± 0.12 °C within the first twenty years; thereafter and until year 1000, temperature decreases only slightly, whereas ocean heat content and sea level continue to rise. Our best estimate for the Absolute Global Warming Potential, given by the time-integrated response in CO2 at year 100 multiplied by its radiative efficiency, is 92.5 × 10−15 yr W m−2 per kg-CO2. This value very likely (5 to 95% confidence) lies within the range of (68 to 117) × 10−15 yr W m−2 per kg-CO2. Estimates for time-integrated response in CO2 published in the IPCC First, Second, and Fourth Assessment and our multi-model best estimate all agree within 15% during the first 100 yr. The integrated CO2 response, normalized by the pulse size, is lower for pre-industrial conditions, compared to present day, and lower for smaller pulses than larger pulses. In contrast, the response in temperature, sea level and ocean heat content is less sensitive to these choices. Although, choices in pulse size, background concentration, and model lead to uncertainties, the most important and subjective choice to determine AGWP of CO2 and GWP is the time horizon.2793-2825513
Servicios Ecosistémicos2013Labarca Encina, R., Pino, M., & Recabarren, O. Los Lamini (Cetartiodactyla: Camelidae) extintos del yacimiento de Pilauco (Norpatagonia chilena): aspectos taxonómicos y tafonómicos preliminaresEstudios Geológicos10.3989/egeol.40862.219 present a preliminary description and taxonomic assignment of the Lamini fossil remains recovered from the paleontological site of Pilauco (late Pleistocene) in southern Chile. Based on metric variables the fossils are temporarily asigned to cf. Hemiauchenia paradoxa Gervais & Ameghino 1880, waiting for new and more diagnostic remains. We present and discuss some taphonomic processes occurring within the site, starting from the study of the marks observed in the surface of the fossils, wich are consistent with the bog environment with occasional fluvial flooding described for the site.255-269269
Servicios Ecosistémicos2013Molina-Montenegro, M. A., Ricote-Martínez, N., Muñoz-Ramírez, C., Gómez-González, S., Torres-Díaz, C., Salgado-Luarte, C., & Gianoli, E.Positive interactions between the lichen Usnea antarctica (Parmeliaceae) and the native flora in Maritime AntarcticaJournal of Vegetation Science10.1111/j.1654-1103.2012.01480.x Is the macrolichen Usnea antarctica a ‘nurse’ species to Antarctic flora? Are positive plant–plant interactions more frequent than negative interactions in Antarctic ecosystems? Are microclimatic modifications by cushions of U. antarctica responsible for the nurse effect? Location Two sites in Antarctica: King George Island, South Shetland (62°11′ S, 58°56′ W; 62°11′ S, 58°59′ W). Methods We evaluated the association of plant species with U. antarctica cushions by recording species growing – in equivalent areas – within and outside U. antarctica cushions. Additionally, we performed transplant experiments with Deschampsia antarctica individuals to assess if U. antarctica cushions enhance plant survival. In both study sites we monitored temperature, moisture and nutrient status of soil outside and within the cushions to provide insights into potential mechanisms underlying possible interactions between U. antarctica and other plant species. Results Eight out of 13 species were positively associated with cushions of the widespread lichen U. antarctica, while only one species (U. aurantiaco-atra) showed a negative association with U. antarctica. Survival of Deschampsia was enhanced when growing associated with U. antarctica cushions. Our results indicate that cushions ameliorated the extreme conditions of Antarctic islands through increased temperature and soil moisture, decreased radiation and evaporative water loss and increased nutrient availability. Conclusions The nurse effect of U. antarctica is verified. Cushions of this macrolichen may be a key component in structuring the Antarctic landscape and maintaining local species richness, and their presence might influence range expansion of other species.463-472324
Servicios Ecosistémicos2013Pino, M., Chávez-Hoffmeister, M., Navarro-Harris, X., & Labarca, R. The late Pleistocene Pilauco site, Osorno, south-central ChileQuaternary International10.1016/j.quaint.2012.05.001 and archaeological sites have frequently been found in open locations of the Intermediate Depression of south-central Chile. This paper presents the results of two field sampling seasons carried out at the Pilauco Site (ca. 39°S) and compares them with those of three well known sites in Chile: Quereo, Tagua-Tagua and Monte Verde, ca. 32°, 34° and 41°S, respectively. Stratigraphic data collected at Pilauco and the resulting radiocarbon age model suggest that before 12,540 ± 90 BP the old Damas River eroded an older volcaniclastic hill, which was followed by a bog formation in an ox-bow lake. The site was developing up to 11,004 ± 186 BP, the date of the youngest vertebrate fossil. Two younger peat beds seal the site. As in Tagua-Tagua and Monte Verde, Gomphotheres are the most represented megafauna. Fossils of Equidae, Camelidae, Cervidae, Mephitidae, Muridae, Myocastoridae and Xenarthra are also found in Pilauco. As a whole, 718 bones, 30 teeth and 11 coprolites represent the extinct and extant vertebrates. Preliminary taphonomic results suggest action of various agents in the bones, i.e. trampling, root etching, abrasion, and carnivore gnawing. The spatial analysis suggests the transfer of smaller anatomical units (e.g. bones of camelids and horses) and the rearrangement of some pieces comparatively large (e.g. gomphothere bones). Similar to the present day north Patagonian landscape, the area where Pilauco site is located had a variety of animal resources, plants and stones in an ecotone between hills, floodplains and wetlands. A total of 101 lithics were recorded: basalt and quartzite were collected from nearby fluvial deposits and dacitic obsidian from the local volcaniclastic deposits. Debitage is the most represented lithic item (75%); cores and marginal edge-trimmed artifacts represented 12 and 13%, respectively. Artifacts and flakes are spatially and temporality associated in the same PB-7 bed with high bone concentrations in some specific areas, between 361 and 424 cm of local altitude. This industry is characterized by a recurrent lithic expedite technology with production of flakes and chips which mastered marginal retouches over the bifacial trimming. This seems to be connected to strategic conditions of high resource diversity, especially of human groups with a high or medium mobility across land. Pilauco represents a site contemporaneous to Monte Verde related as well to the first human occupation in the southern cone of South America, but with higher mammal diversity.3-12299
Dinámica del Clima2013Power, M. J., Mayle, F. E., Bartlein, P. J., Marlon, J. R., Anderson, R. S., Behling, H., Moreno, P.I, … Walsh, M. K. Climatic control of the biomass-burning decline in the Americas after ad 1500The Holocene10.1177/0959683612450196 significance and cause of the decline in biomass burning across the Americas after ad 1500 is a topic of considerable debate. We synthesized charcoal records (a proxy for biomass burning) from the Americas and from the remainder of the globe over the past 2000 years, and compared these with paleoclimatic records and population reconstructions. A distinct post-ad 1500 decrease in biomass burning is evident, not only in the Americas, but also globally, and both are similar in duration and timing to ‘Little Ice Age’ climate change. There is temporal and spatial variability in the expression of the biomass-burning decline across the Americas but, at a regional–continental scale, ‘Little Ice Age’ climate change was likely more important than indigenous population collapse in driving this decline.3-13123
Modelación y Sistemas de Observación2013Rojas, M. Sensitivity of Southern Hemisphere circulation to LGM and 4 × CO2 climatesGeophysical Research Letters10.1002/grl.50195 paper investigates the effect of Last Glacial Maximum (LGM) versus high CO2 world boundary condition on the Southern Hemisphere atmospheric circulation, in particular on the strength and latitudinal position of the near surface Southern Westerly Winds (SWW). PMIP2 and PMIP3 experiments, as well as the “abrupt 4 × CO2” simulations from CMIP5, were analyzed. Robust findings include poleward expansion of the Mean Meridional Circulation (MMC) and intensified and poleward-shifted SWW in the 4 × CO2 simulations (consistent with recent observations and 21st century climate change projections); and for the LGM, stronger and southward shifted northern hemisphere MMC, and weakened southern Hadley cell. However, six of the eight LGM simulations show a decrease in the SWW, the other two models simulate the opposite. A critical difference between the models is strong coupling between sea-ice extent, surface temperature gradients, SWW, and Ferrel cell in the two models with stronger and poleward-shifted SWW.965-970540
Modelación y Sistemas de Observación2013Rojas, M., Li, L. Z., Kanakidou, M., Hatzianastassiou, N., Seze, G., & Treut, H. L. Winter weather regimes over the Mediterranean region: their role for the regional climate and projected changes in the twenty-first centuryClimate Dynamics10.1007/s00382-013-1823-8 winter time weather variability over the Mediterranean is studied in relation to the prevailing weather regimes (WRs) over the region. Using daily geopotential heights at 700 hPa from the ECMWF ERA40 Reanalysis Project and Cluster Analysis, four WRs are identified, in increasing order of frequency of occurrence, as cyclonic (22.0 %), zonal (24.8 %), meridional (25.2 %) and anticyclonic (28.0 %). The surface climate, cloud distribution and radiation patterns associated with these winter WRs are deduced from satellite (ISCCP) and other observational (E-OBS, ERA40) datasets. The LMDz atmosphere–ocean regional climate model is able to simulate successfully the same four Mediterranean weather regimes and reproduce the associated surface and atmospheric conditions for the present climate (1961–1990). Both observational- and LMDz-based computations show that the four Mediterranean weather regimes control the region’s weather and climate conditions during winter, exhibiting significant differences between them as for temperature, precipitation, cloudiness and radiation distributions within the region. Projections (2021–2050) of the winter Mediterranean weather and climate are obtained using the LMDz model and analysed in relation to the simulated changes in the four WRs. According to the SRES A1B emission scenario, a significant warming (between 2 and 4 °C) is projected to occur in the region, along with a precipitation decrease by 10–20 % in southern Europe, Mediterranean Sea and North Africa, against a 10 % precipitation increase in northern European areas. The projected changes in temperature and precipitation in the Mediterranean are explained by the model-predicted changes in the frequency of occurrence as well as in the intra-seasonal variability of the regional weather regimes. The anticyclonic configuration is projected to become more recurrent, contributing to the decreased precipitation over most of the basin, while the cyclonic and zonal ones become more sporadic, resulting in more days with below normal precipitation over most of the basin, and on the eastern part of the region, respectively. The changes in frequency and intra-seasonal variability highlights the usefulness of dynamics versus statistical downscaling techniques for climate change studies.551-5713-441
Servicios Ecosistémicos2013Swanson, F. J., Jones, J. A., Crisafulli, C. M., & Lara, A. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, ChileAndean Geology10.5027/andgeoV40n2-a10 2008-2009 eruption of Chaitén Volcano (Chile) involved a variety of volcanic and associated hydrologic processes that damaged nearby forests. These processes included coarse (gravel) and fine (silt to sand) tephra fall, a laterally directed blast, fluvial deposition of remobilized tephra, a variety of low-temperature mass-movement processes, and a pyroclastic flow. Each of these geophysical processes constitutes a type of ecosystem disturbance which involves a distinctive suite of disturbance mechanisms, namely burial by tephra and sediment, heating, abrasion, impact force, and canopy loading (accumulation of tephra in tree crowns). Each process affected specific areas, and created patches and disturbance gradients in the forest landscape. Coarse tephra (‘gravel rain’, >5 cm depth) abraded foliage from tree canopies over an area of approximately 50 km2 north-northeast of the vent. Fine tephra (>10 cm depth) accumulated in tree crowns and led to breakage of branches in old forest and bowing of flexible, young trees over an area of about 480 km2. A directed blast down the north flank of the volcano damaged forest over an area of 4 km2. This blast zone included an area of tree removal near the crater rim, toppled forest farther down the slope, and standing, scorched forest around the blast perimeter. Fluvial deposition of >100 cm of remobilized tephra, beginning about 10 days after initiation of the eruption, buried floodplain forest in distinct, elongate streamside patches covering 5 km2 of the lower 19 km of the Rayas River and several km2 of the lower Chaitén River. Across this array of disturbance processes the fate of affected trees varied from complete mortality in the tree removal and pyroclastic flow areas, to no mortality in areas of thin tephra fall deposits. Tree damage included defoliation, loss of branches, snapping of tree trunks, abrasion of bark and ephiphytes, and uprooting. Damaged trees sprouted from epicormic buds located in trunks and branches, but sprouting varied over time among disturbance mechanisms and species. Although some effects of the Chaitén eruption are very similar to those from the 1980 eruption of Mount St. Helens (USA), interactions between biota and geophysical processes at Chaitén produced some unique effects. Examination of vegetation response helps interpret geophysical processes, and disturbance mechanisms influence early stages of biotic response to an eruption.240
Modelación y Sistemas de Observación2013Zickfeld, K., Eby, M., Weaver, A. J., Alexander, K., Crespin, E., Edwards, N. R., Shaffer, G., … Zhao, F.Long-Term Climate Change Commitment and Reversibility: An EMIC IntercomparisonJournal of Climate10.1175/JCLI-D-12-00584.1 paper summarizes the results of an intercomparison project with Earth System Models of Intermediate Complexity (EMICs) undertaken in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The focus is on long-term climate projections designed to 1) quantify the climate change commitment of different radiative forcing trajectories and 2) explore the extent to which climate change is reversible on human time scales. All commitment simulations follow the four representative concentration pathways (RCPs) and their extensions to year 2300. Most EMICs simulate substantial surface air temperature and thermosteric sea level rise commitment following stabilization of the atmospheric composition at year-2300 levels. The meridional overturning circulation (MOC) is weakened temporarily and recovers to near-preindustrial values in most models for RCPs 2.6–6.0. The MOC weakening is more persistent for RCP8.5. Elimination of anthropogenic CO2 emissions after 2300 results in slowly decreasing atmospheric CO2 concentrations. At year 3000 atmospheric CO2 is still at more than half its year-2300 level in all EMICs for RCPs 4.5–8.5. Surface air temperature remains constant or decreases slightly and thermosteric sea level rise continues for centuries after elimination of CO2 emissions in all EMICs. Restoration of atmospheric CO2 from RCP to preindustrial levels over 100–1000 years requires large artificial removal of CO2 from the atmosphere and does not result in the simultaneous return to preindustrial climate conditions, as surface air temperature and sea level response exhibit a substantial time lag relative to atmospheric CO2.5782-58091626
Dinámica del Clima; Servicios Ecosistémicos2013Ahmed, M., Anchukaitis, K. J., Asrat, A., Borgaonkar, H. P., Braida, M., Buckley, B. M., … Zorita, E.Continental-scale temperature variability during the past two millenniaNature Geoscience10.1038/NGEO1797 global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi- decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years. D339–346April6
Biogeoquímica2013Daniel, I., DeGrandpre, M., & Farías, L.Greenhouse gas emissions from the Tubul-Raqui estuary (central Chile 36°S)Estuarine, Coastal and Shelf Science10.1016/j.ecss.2013.09.019 Tubul-Raqui estuary is a coastal system off central Chile at 37°S, adjacent to an active coastal upwelling area, which undergoes rapid changes associated with natural and anthropogenic perturbations. Biogenic greenhouse gas cycling and the gas saturation levels are good indicators of microbial metabolism and trophic status in estuaries. The dissolved greenhouse gases CO2, CH4 and N2O and other biological and chemical variables were spatially recorded in this estuary over two seasons (summer and winter) and over one-half of one tidal cycle. Tidal and spatial variability of these gases indicated they had different origins within the system. Surface waters were always oversaturated in CO2 (up to 578%) and CH4 (up to 6200%) with respect to the atmosphere. But while CO2 seems to come from marine and in situ metabolism, CH4 appears to be more influenced by fluvial and adjacent salt marsh areas. In contrast, N2O was mostly undersaturated and sediments seem to be largely responsible for its consumption. Strong seasonal variability was also observed in CO2 and CH4 fluxes, being tenfold (from-319 to 714mmolm-2d-1) and fivefold (from 0.33 to 2.5mmolm-2d-1) higher, respectively, in the austral summer compared to winter. In contrast, only small seasonal differences in N2O fluxes were found ranging from -59 to 28 μmol m-2 d-1. These temporal patterns can be explained not only in terms of hydrological and nutrient balances within the system, but also by the influence of wind-driven upwelling processes. Additionally, potential effects of changes in nutrient load and freshwater discharge on net ecosystem metabolism (i.e., autotrophy or heterotrophy) and therefore, on the production/removal of greenhouse gases in this system were explored. © 2013 Elsevier Ltd.31–44134
Biogeoquímica2013Farías, L., Faúndez, J., Fernández, C., Cornejo, M., Sanhueza, S., & Carrasco, C.Biological N2O fixation in the Eastern South Pacific Ocean and marine cyanobacterial cultures.PloS one10.1371/journal.pone.0063956 the importance of nitrous oxide (N2O) in the global radiative balance and atmospheric ozone chemistry, its sources and sinks within the Earth's system are still poorly understood. In the ocean, N2O is produced by microbiological processes such as nitrification and partial denitrification, which account for about a third of global emissions. Conversely, complete denitrification (the dissimilative reduction of N2O to N2) under suboxic/anoxic conditions is the only known pathway accountable for N2O consumption in the ocean. In this work, it is demonstrated that the biological assimilation of N2O could be a significant pathway capable of directly transforming this gas into particulate organic nitrogen (PON). N2O is shown to be biologically fixed within the subtropical and tropical waters of the eastern South Pacific Ocean, under a wide range of oceanographic conditions and at rates ranging from 2 pmol N L(-1) d(-) to 14.8 nmol N L(-1) d(-1) (mean ± SE of 0.522 ± 1.06 nmol N L(-1) d(-1), n = 93). Additional assays revealed that cultured cyanobacterial strains of Trichodesmium (H-9 and IMS 101), and Crocosphaera (W-8501) have the capacity to directly fix N2O under laboratory conditions; suggesting that marine photoautotrophic diazotrophs could be using N2O as a substrate. This metabolic capacity however was absent in Synechococcus (RCC 1029). The findings presented here indicate that assimilative N2O fixation takes place under extreme environmental conditions (i.e., light, nutrient, oxygen) where both autotrophic (including cyanobacteria) and heterotrophic microbes appear to be involved. This process could provide a globally significant sink for atmospheric N2O which in turn affects the oceanic N2O inventory and may also represent a yet unexplored global oceanic source of fixed N.e6395658
Biogeoquímica2013Florez-Leiva, L., Damm, E., & Farías, L.Methane production induced by dimethylsulfide in surface water of an upwelling ecosystemProgress in Oceanography10.1016/j.pocean.2013.03.005 upwelling ecosystems are areas of high productivity and strong outgassing, where most gases, such as N2O and CH4, are produced in subsurface waters by anaerobic metabolisms. We describe seasonal CH4 variation as well as potential mechanisms producing CH4 in surface waters of the central Chile upwelling ecosystem (36°S). Surface waters were always supersaturated in CH4 (from 125% up to 550%), showing a clear seasonal signal triggered by wind driven upwelling processes (austral spring-summer period), that matched with the periods of high chlorophyll-a and dimethylsulfoniopropionate (DMSP) levels. Methane cycling experiments, with/without the addition of dimethylsulfide (including 13C-DMS) and acetylene (a nonspecific inhibitor of CH4 oxidation) along with monthly measurements of CH4, DMSP and other oceanographic variables revealed that DMS can be a CH4 precursor. Net CH4 cycling rates (control) fluctuated between -0.64 and 1.44nmolL-1d-1. After the addition of acetylene, CH4 cycling rates almost duplicated relative to the control, suggesting a strong methanotrophic activity. With a spike of DMS, the net CH4 cycling rate significantly increased relative to the acetylene and control treatment. Additionally, the δ13C values of CH4 at the end of the incubations (after addition of 13C enriched-DMS) were changed, reaching -32‰ PDB compared to natural values between -44‰ and -46‰ PDB. These findings indicate that, in spite of the strong CH4 consumption by methanotrophs, this upwelling area is an important source of CH4 to the atmosphere. The effluxes are derived partially from in situ surface production and seem to be related to DMSP/DMS metabolism. © 2013 Elsevier Ltd.38–48112-113
Biogeoquímica2013Galbraith, E. D., Kienast, M., Albuquerque, A. L., Altabet, M. A., Batista, F., Bianchi, D., de Pol-Holz, R., … Terence Yang, J.-Y.The acceleration of oceanic denitrification during deglacial warmingNature Geoscience10.1038/ngeo1832 much of the ocean’s surface, productivity and growth are limited by a scarcity of bioavailable nitrogen. Sedimentary δ15N records spanning the last deglaciation suggest marked shifts in the nitrogen cycle during this time, but the quantification of these changes has been hinderedby the complexity of nitrogen isotope cycling. Herewe present a database of δ15Nin sediments throughout the world’s oceans, including 2,329 modern seafloor samples, and 76 timeseries spanning the past 30,000 years. We showthat the δ15Nvalues of modern seafloor sediments are consistent with values predicted by our knowledge of nitrogen cycling in thewater column. Despite many local deglacial changes, the globally averaged δ15N values of sinking organic matter were similar during the Last Glacial Maximum and Early Holocene. Considering the global isotopic mass balance, we explain these observations with the following deglacial history of nitrogen inventory processes. During the Last Glacial Maximum, the nitrogen cycle was near steady state. During the deglaciation, denitrification in the pelagic water column accelerated. The flooding of continental shelves subsequently increased denitrification at the seafloor, and denitrification reached near steady-state conditions again in the Early Holocene.We use a recent parameterization of seafloor denitrification to estimate a 30–120% increase in benthic denitrification between 15,000 and 8,000 years ago. Based on the similarity of globally averaged δ15N values during the Last Glacial Maximum and Early Holocene, we infer that pelagic denitrification must have increased by a similar amount between the two steady states.579–58476
Dinámica del Clima2013Garreaud, R.Warm Winter Storms in Central ChileJournal of Hydrometeorology10.1175/JHM-D-12-0135.1 Chile is a densely populated region along the west coast of subtropical SouthAmerica (30°-36°S), limited to the east by the Andes. Precipitation is concentrated in austral winter, mostly associated with the passage of cold fronts. The freezing level over central Chile is typically between 1500 and 2500m when precipitation is present. In about a third of the cases, however, precipitation occurs accompanied by warm temperatures and freezing levels above 3000 m, leading to a sizeable increment in the pluvial area of Andean basins and setting the stage for hydrometeorological hazards. Here, warm winter storms in central Chile are studied, including a statistical description of their occurrence and an estimate of their hydrological impacts. Remote-sensed data and high-resolution reanalysis are used to explore the synoptic-scale environment of a typical case, generalized later by a compositing analysis. The structure of warm storms is also contrasted with that of the more recurrent cold cases. Precipitation during warm events occurs in the warm sector of a slow-moving cold front because of the intense moisture flux against the mountains in connection with a land-falling atmospheric river. This is in turn driven by a strong zonal jet aloft and reduced mechanical blocking upstream of the Andes. On a broader scale, a key element is the presence of a slowly moving anticyclone over the south Pacific, fostering advection of cold air intomidlatitudes. The intense and persistent zonal jet stretches a moist-air corridor from the central Pacific to the west coast of South America. © 2013 American Meteorological Society.1515–1534514
Dinámica del Clima2013Li, J., Xie, S.-P., Cook, E. R., Morales, M. S., Christie, D. A., Johnson, N. C., … Fang, K.El Niño modulations over the past seven centuriesNature Climate Change10.1038/nclimate1936 how the El Niño/Southern Oscillation (ENSO) will change with global warming is of enormous importance to society. ENSO exhibits considerable natural variability at interdecadal-centennial timescales. Instrumental records are too short to determine whether ENSO has changed and existing reconstructions are often developed without adequate tropical records. Here we present a seven-century-long ENSO reconstruction based on 2,222 tree-ring chronologies from both the tropics and mid-latitudes in both hemispheres. The inclusion of tropical records enables us to achieve unprecedented accuracy, as attested by high correlations with equatorial Pacific corals and coherent modulation of global teleconnections that are consistent with an independent Northern Hemisphere temperature reconstruction. Our data indicate that ENSO activity in the late twentieth century was anomalously high over the past seven centuries, suggestive of a response to continuing global warming. Climate models disagree on the ENSO response to global warming, suggesting that many models underestimate the sensitivity to radiative perturbations. Illustrating the radiative effect, our reconstruction reveals a robust ENSO response to large tropical eruptions, with anomalous cooling in the east-central tropical Pacific in the year of eruption, followed by anomalous warming one year after. Our observations provide crucial constraints for improving climate models and their future projections. © 2013 Macmillan Publishers Limited. All rights reserved.822–82693
Biogeoquímica2013Martínez-Méndez, G., Hebbeln, D., Mohtadi, M., Lamy, F., de Pol-Holz, R., Reyes-Macaya, D., & Freudenthal, T.Changes in the advection of Antarctic Intermediate Water to the northern Chilean coast during the last 970 kyrPaleoceanography10.1002/palo.20047 Antarctic Intermediate Water (AAIW) is a key player in global-scale oceanic overturning processes and an important conduit for heat, fresh water, and carbon transport. The AAIW past variability is poorly understood mainly due to the lack of sedimentary archives at intermediate water depths. We present records of benthic stable isotopes from sediments retrieved with the seafloor drill rig MARUM-MeBo at 956 m water depth off northern Chile (GeoB15016, 27°29.48′S, 71°07.58′W) that extend back to 970 ka. The sediments at this site are presently deposited at the boundary between AAIW and Pacific Deep Water (PDW). For previous peak interglacials, our results reveal similar benthic δ13C values at site GeoB15016 and of a newly generated stack of benthic δ13C from various deep Pacific cores representing the "average PDW." This suggests, unlike today, the absence of AAIW at the site and the presence of nearly pure PDW. In contrast, more positive δ13C values at site GeoB15016 compared to the stack imply a considerable AAIW contribution during cold phases of interglacials and especially during glacials. Besides, we used three short sediment cores to reconstruct benthic δ13C values from the AAIW core during the last glacial and found a δ13C signature similar to today's. Assuming that this was the case also for the past 970 kyr, we demonstrate that sea level changes and latitudinal migrations of the AAIW formation site can only account for about 50% of the full range of past δ13C increases at site GeoB15016 during cold periods. Other processes that could explain the remaining of the positive δ13C anomalies are increases in glacial AAIW production and/or deeper convection of the AAIW with respect to preceding interglacials. Key Points Absence of AAIW off northern Chile during past peak interglacial periods Increase advection of AAIW to the northern Chilean margin during cold periods Present and LGM AAIW production similar and the highest since 970 ka ©2013. American Geophysical Union. All Rights Reserved.607–618428
Dimensión Humana; Servicios Ecosistémicos2013Mastrangelo, M. E., Weyland, F., Villarino, S. H., Barral, M. P., Nahuelhual, L., & Laterra, P.Concepts and methods for landscape multifunctionality and a unifying framework based on ecosystem servicesLandscape Ecology10.1007/s10980-013-9959-9 potential of landscapes to supply multiple benefits to society beyond commodities production has received increasing research and policy attention. Linking the concept of multifunctionality with the ecosystem services (ES) approach offers a promising avenue for producing scientific evidence to inform landscape planning, e.g., about the relative utility of land-sharing and land-sparing. However, the value for decision-making of ES-based multifunctionality assessments has been constrained by a significant conceptual and methodological dispersion. To contribute towards a cohesive framework for landscape multifunctionality, we analyse case studies of joint ES supply regarding ten criteria designed to ultimately answer four aspects: (i) the multifunctionality of what (e.g., landscapes), (ii) the type of multifunctionality (e.g., based on ES synergies), (iii) the procedure of multifunctionality assessments, and (iv) the purpose of multifunctionality. We constructed a typology of methodological approaches based on scores for criteria describing the evaluation method and the level of stakeholder participation in assessments of joint ES supply. Surveyed studies and underlying types of methodological approaches (spatial, socio-spatial, functional, spatio-functional) differed in most criteria. We illustrate the influence of methodological divergence on planning recommendations by comparing two studies employing contrasting approaches (spatial and functional) to assess the joint supply of wildlife habitat and agricultural production in the Argentine Chaco. We distinguish between a pattern-based and process-based multifunctionality, where the latter can only be detected through approaches considering the ecological processes (e.g., ES complementarities) supporting the supply of multiple ES (functional and spatio-functional). Finally, we propose an integrated approach for assessing a socially-relevant process-based multifunctionality. © 2013 Springer Science+Business Media Dordrecht.345–358229
Dimensión Humana; Servicios Ecosistémicos2013Nahuelhual, L., Carmona, A., Aguayo, M., & Echeverría, C.Land use change and ecosystem services provision: a case study of recreation and ecotourism opportunities in southern ChileLandscape Ecology10.1007/s10980-013-9958-x use and cover change (LUCC) is among the most important factors affecting ecosystem services. This study examines the influence of LUCC on recreation and ecotourism opportunities over three decades in southern Chile. An in-depth analysis of the transition matrix was conducted based on Landsat images from 1976, 1985, 1999 and 2007. Main LUCC trajectories were linked to two ecosystem service indicators: (i) Recreation and ecotourism potential, measured in a 0-100 point scale; and (ii) Recreation and ecotourism opportunities, measured in visitors/ha. A total of 900 trajectories occurred in the landscape between 1976 and 2007. The most important trajectories in terms of area, were the recent degradation of old-growth to secondary forest between 1999 and 2007 (23,290 ha; 13.5 % of landscape), and the early clearing of shrublands for agriculture and pasture land between 1976 and 1985 (7,187 ha, 4.2 % of landscape). In turn, the single most influential trajectory on the magnitude of the indicators was early and permanent degradation of old-growth forest to secondary forest. As a result of these landscape changes, recreation and ecotourism opportunities for the entire landscape were reduced from 65,050 persons in 1976 to 25,038 persons in 1985, further declining to 22,346 and 21,608 persons in 1999 and 2007, respectively. This decrease resulted from changes in specific attributes (i.e. emblematic flora and fauna and forest structure) that were affected by forest degradation and fragmentation. These results highlight the substantial impact of LUCC on recreation opportunity decline, which mirrors biodiversity losses in the study area. © 2013 Springer Science+Business Media Dordrecht.329–344229
Modelación y Sistemas de Observación2013Osses, A., Gallardo, L., & Faundez, T.Analysis and evolution of air quality monitoring networks using combined statistical information indexesTellus B10.3402/tellusb.v65i0.19822 this work, we present combined statistical indexes for evaluating air quality monitoring networks based on concepts derived from the information theory and Kullback–Liebler divergence. More precisely, we introduce: (1) the standard measure of complementary mutual information or ‘specificity’ index; (2) a new measure of information gain or ‘representativity’ index; (3) the information gaps associated with the evolution of a network and (4) the normalised information distance used in clustering analysis. All these information concepts are illustrated by applying them to 14 yr of data collected by the air quality monitoring network in Santiago de Chile (33.5 S, 70.5 W, 500 m a.s.l.). We find that downtown stations, located in a relatively flat area of the Santiago basin, generally show high ‘representativity’ and low ‘specificity’, whereas the contrary is found for a station located in a canyon to the east of the basin, consistently with known emission and circulation patterns of Santiago. We also show interesting applications of information gain to the analysis of the evolution of a network, where the choice of background information is also discussed, and of mutual information distance to the classifications of stations. Our analyses show that information as those presented here should of course be used in a complementary way when addressing the analysis of an air quality network for planning and evaluation purposes.19822065
Dimensión Humana2013Romero-Lankao, P., Hughes, S., Rosas-Huerta, A., Borquez, R., & Gnatz, D. M.Institutional capacity for climate change responses: an examination of construction and pathways in Mexico City and SantiagoEnvironment and Planning C: Government and Policy10.1068/c12173 have focused on understanding the motivations behind urban authorities' efforts to respond to climate change, yet the determinants of institutional response capacity are less well known, particularly in Latin America. This paper develops a framework to understand the political-economic determinants of institutional response capacity through an examination of climate change governance in Mexico City and Santiago, Chile. We ask whether being a frontrunner (Mexico City) is an indicator of greater institutional response capacity. Although Mexico City has slightly higher levels of institutional capacity than Santiago, both are faced with similar challenges, such as fragmented governance arrangements, asymmetries in access to information, and topdown decision making. However, both also have similar opportunities, such as leadership, participation in transnational networks, and potential to integrate climate change goals into existing policy agendas. Examining urban climate change planning in isolation from other institutions is therefore likely to provide a false sense of a city's response capacity.785–805531
Dinámica del Clima2013Rutllant, J., Muñoz, R. C., & Garreaud, R.Meteorological observations on the northern Chilean coast during VOCALS-RExAtmospheric Chemistry and Physics10.5194/acp-13-3409-2013 coastal observations from two automatic weather stations at Paposo (∼25 °S) and radiosonde observations at Paposo and Iquique (∼20 °S) were carried out during VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment). Within the coastal marine boundary layer (MBL), sea-land breezes are superimposed on the prevailing southerlies, resulting in light northeasterly winds from midnight to early morning and strong southwesterlies in the afternoon. The prevailing northerlies above the MBL and below the top of the Andes are modulated by the onshore-offshore (zonal) flow forced by the diurnal cycle of surface heating/cooling along the western slope of the Andes. The daytime phase of this diurnal cycle is consistent with an enhanced afternoon coastal subsidence manifested in afternoon warming near the top of the subsidence inversion (∼1.8 K at 800 hPa), lowering (∼130 m) of its base (top of the MBL), and clearing of coastal Sc (stratocumulus) clouds. Results from a numerical simulation of the atmospheric circulation in a mean zonal cross section over the study area capture the afternoon zonal wind divergence and resulting subsidence of about 2 cm s-1 along a narrow (∼10 km) coastal strip maximizing at around 800 hPa. Day-to-day variability in the MBL depth during VOCALS-REx shows sub-synoptic oscillations, aside from two major disruptions in connection with a deep trough and a cutoff low, as described elsewhere. These oscillations are phase-locked to those in sea-level pressure and afternoon alongshore southerlies, as found in connection with coastal lows farther south. From 24-h forward trajectories issued from significant points at the coast and inland at the extremes of the diurnal cycle, it can be concluded that the strong mean daytime Andean pumping prevents any possibility of continental sulfur sources from reaching the free troposphere above the Sc cloud deck in at least a one-day timescale, under mean conditions. Conversely, coastal sources could contribute with sulfur aerosols preferentially in the morning, provided that the weak daytime inland flow becomes partially blocked by the coastal terrain. © 2013 Author(s). CC Attribution 3.0 License.3409–3422613
Biogeoquímica2013Seguel, R. J., Mancilla, C. A., Rondanelli, R., Leiva, M. A., & Morales, R. G. E.Ozone distribution in the lower troposphere over complex terrain in Central ChileJournal of Geophysical Research: Atmospheres10.1002/jgrd.50293 were performed in 12 communities of Central Chile in order to determine the horizontal gradients of ozone in the Santiago Basin and surrounding valleys. Higher ozone mixing ratios were found northeast of the Santiago Basin and included east of the Aconcagua Valley (∼70 km from Santiago) suggesting that photochemical pollution produced in Santiago is capable of passing through the Chacabuco mountain chain (∼1.3 km) and have impact downwind from the regions with the largest NOx and VOC emissions. To complement existing surface observations, ozonesonde and tethersonde campaigns were performed in the Santiago Basin and the Aconcagua Valley. The results suggest ozone can accumulate in layers aloft (e.g., >102 ppb at 2 km) similarly to layers observed in complex topography coastal regions like Southern California. Layers of significant ozone concentrations having a near surface origin were observed above the mixed layer and below the subsidence inversion base. We propose that the ozone in this residual layer can be transported large distances (at least to 70 km) to further penetrate into the local environment under conditions of a well-mixed boundary layer. © 2013. American Geophysical Union. All Rights Reserved.2966–29807118
Biogeoquímica2013Siani, G., Michel, E., de Pol-Holz, R., Devries, T., Lamy, F., Carel, M., … Lourantou, A.Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation.Nature communications10.1038/ncomms3758 Southern Ocean plays a prominent role in the Earth's climate and carbon cycle. Changes in the Southern Ocean circulation may have regulated the release of CO₂ to the atmosphere from a deep-ocean reservoir during the last deglaciation. However, the path and exact timing of this deglacial CO₂ release are still under debate. Here we present measurements of deglacial surface reservoir ¹⁴C age changes in the eastern Pacific sector of the Southern Ocean, obtained by ¹⁴C dating of tephra deposited over the marine and terrestrial regions. These results, along with records of foraminifera benthic-planktic ¹⁴C age and δ¹³C difference, provide evidence for three periods of enhanced upwelling in the Southern Ocean during the last deglaciation, supporting the hypothesis that Southern Ocean upwelling contributed to the deglacial rise in atmospheric CO₂. These independently dated marine records suggest synchronous changes in the Southern Ocean circulation and Antarctic climate during the last deglaciation.27584
Dinámica del Clima2014Aguirre, C., Garreaud, R., & Rutllant, J. A.Surface ocean response to synoptic-scale variability in wind stress and heat fluxes off south-central ChileDynamics of Atmospheres and Oceans10.1016/j.dynatmoce.2013.11.001 effect of the high frequency (synoptic) variability of wind and heat fluxes upon the surface ocean off south-central Chile (west coast of South America) is investigated using a regional ocean model. We focus our analysis in austral summer, when the regional wind experiences significant day-to-day variability superimposed on a mean, upwelling favorable flow. To evaluate the nature and magnitude of these effects, we performed three identical simulations except for the surface forcing: the climatological run, with long-term monthly mean wind-stresses and heat fluxes; the wind-synoptic run, with daily wind stresses and climatological heat fluxes; and the full-synoptic run, with daily wind-stresses and daily fluxes. The mean currents and surface geostrophic EKE fields show no major differences between simulations, and agree well with those observed in this ocean area. Nevertheless, substantially more ageostrophic EKE is found in the simulations which include synoptic variability of wind-stresses, impacting the total surface EKE and diffusivities, particularly south of Punta Lavapie (37°. S), where the lack of major currents implies low levels of geostrophic EKE. Summer mean SSTs are similar in all simulations and agree with observations, but SST variability along the coast is larger in the runs including wind-stress synoptic variability, suggesting a rather linear response of the ocean to cycles of southerly wind strengthening and relaxation. We found that coastal SST variability does not change significantly in the first tenths of kilometers from the shore when including daily heat fluxes, highlighting the prominent role of wind-driven upwelling cycles. In contrast, in the offshore region situated beyond the 50. km coastal strip, it is necessary to include synoptic variability in the heat fluxes to account for a realistic SST variability. © 2013 The Authors.64–8565
Dimensión Humana2014Aldunce, P., Beilin, R., Handmer, J., & Howden, M.Framing disaster resilience: The implications of the diverse conceptualisations of “bouncing back”Disaster Prevention and Management10.1108/DPM-07-2013-0130 To confront the increasingly devastating impacts of disasters and the challenges that climate change is posing to disaster risk management (DRM) there is an imperative to further develop DRM. The resilience approach is emerging as one way to do this, and in the last decade has been strongly introduced into the policy arena, although it is not new for DRM practitioners and researchers. Nevertheless, resilience is a highly contested issue, and there is no agreed definition of it, which has resulted in confusion for stakeholders when applying it to practice. Therefore, the purpose of this paper is to investigate how resilience is framed by researchers and DRM practitioners. Design/methodology/approach: The analytical framework used was Hajer's "social-interactive discourse theory", combined with analysis of government documents, in-depth interviews with practitioners and observation of field and practices within the context of the Natural Disaster Resilience Program in Queensland, Australia. Findings: One of the key findings is that the idea of "bouncing back" is central to the resilience discourse but different interpretations of this idea results in real-world implications. Three different ways (storylines) in which practitioners construct the meaning of disaster resilience emerge from this study. Importantly the divergences between these storylines reveal possibilities for reframing to occur and these could lead to different policy options and practices. Originality/value: The results presented in this paper offer empirical evidence on how resilience is understood on the ground, contributing to extending resilience theory and informing DRM and resilience practice. © Emerald Group Publishing Limited.252–270323
Biogeoquímica; Modelación y Sistemas de Observación2014Escribano, J., Gallardo, L., Rondanelli, R., & Choi, Y. S.Satellite retrievals of aerosol optical depth over a subtropical urban area: The role of stratification and surface reflectanceAerosol and Air Quality Research10.4209/aaqr.2013.03.0082 explore the relationship between satellite retrievals of aerosol optical depth (AOD) and surface aerosol mass concentrations over a subtropical urban area, namely, Santiago, Chile (33.5°S, 70.6°W, 500 m.a.s.l.). We compare 11 years of AOD from the MODerate resolution Imaging Spectroradiometer (MODIS) with in situ particulate matter mass concentrations (PM). MODIS AOD reaches its maximum in summer and minimum in winter, the opposite of the annual cycle of surface PM. To improve our understanding of the relevant governing processes, we use a simple model that estimates the boundary layer (BL) AOD based on measured PM, relative humidity and BL height (BLH) as well as best estimates of aerosol composition, size distribution, and optical properties. Model results indicate that a weak annual AOD cycle is due to the opposite annual cycles in BLH and PM, which is largely supported by the Aerosol Robotic NETwork (AERONET) data collected in 2001 and 2002 in Santiago. We identify a possible bias linked to the operational estimate of surface reflectance that may lead to a spurious summer maximum in MODIS AOD over Santiago. This misfit in surface reflectance appears to affect not only Santiago but also a significant area of the semi-arid Southern South America. Sensitivity experiments with the simple model indicate an underestimate of simulated AOD as compared to AERONET data. This underestimate points to the possible role of residual aerosol layers in the AOD measured at the surface (not included in the simple model). Cirrus clouds appear not to play a significant role in explaining the MODIS AOD seasonality. The need for improved characterizations of aerosol properties and their temporal and spatial distribution in cities such as Santiago is emphasized.596–607314
Dinámica del Clima2014Flores, F., Garreaud, R., & Muñoz, R. C.OpenFOAM applied to the CFD simulation of turbulent buoyant atmospheric flows and pollutant dispersion inside large open pit mines under intense insolationComputers & Fluids10.1016/j.compfluid.2013.11.012 particular conditions of air circulation inside large open pit mines under intense insolation, dominated by mechanical and buoyant effects, are crucial when studying the dispersion of pollutants inside and outside the pit. Considering this, we study this problem using CFD tools able to include the complex geometry characterizing it and the different processes affecting circulation: flow interaction with obstacles, buoyancy, stratification and turbulence. We performed simulations using a previously developed OpenFOAM solver, focusing in the particular case of Chuquicamata, a large open pit mine (∼1. km deep) located in northern Chile. Both idealized and real topographies were used. Given the importance of turbulence in this type of large-scale flows we have used LES to incorporate it in the calculation, using a DES approach to solve the flow near walls.The results from the idealized cases support the idea that buoyant currents foster the exit of particles from the pit and increase the turbulence inside its atmosphere, modifying the purely mechanical recirculatory flow inside the cavity. Differences in the air circulation and dispersion of particles between idealized and non-idealized cases are reported. In particular, there are changes in the intensity and location of the recirculation inside the pit due to variations in the aspect ratio (length/depth) of the cavity along the axis perpendicular to the main flow. Also, the topography surrounding the mine affects the main flow that sweeps the cavity, channeling it along the main axis of the pit and forcing it to enter the cavity through the lower level of the top edge. As a consequence, the patterns of pollutant transport observed in the idealized cases, dominated by near-wall upward currents, are different than those observed in the cases with complex topography, where the dispersion is dominated by internal buoyant upward currents. Anyhow, whether by internal or near wall upward currents, in all buoyant cases considered a large percentage of the particles injected inside the pit leaves the cavity.Further experiments studying the effect of 3D aspect ratio over the mechanically forced internal flow are needed to fully understand the effect of the internal geometry of the pit over the flow. © 2013 Elsevier Ltd.72–8790
Biogeoquímica2014Galán, A., Faúndez, J., Thamdrup, B., Santibáñez, J. F., & Farías, L.Temporal dynamics of nitrogen loss in the coastal upwelling ecosystem off central Chile: Evidence of autotrophic denitrification through sulfide oxidationLimnology and Oceanography10.4319/lo.2014.59.6.1865 upwelling areas are highly productive marine systems in which the development of oxygen-depleted conditions and the availability of diverse electron donors (e.g., organic matter, NHz 4 ,H2S) favor the processes involved in nitrogen (N) loss. We characterize the temporal and vertical variability of anammox and denitrification over the continental shelf off central Chile (36.5°S), through 15N and 13C tracer experiments, including amendments with H2S and S2O2- 3 along with measurements of 15N2 and 15N2O production and oceanographic variables during a year (2009 to 2010). Restricted to the bottom waters, both anammox and denitrification contributed similarly (∼ 500 nmol N2 L-1 d-1) to N loss during spring, while a marked decrease in the activity of these processes occurred in summer (103 and 14 nmolN2 L-1 d-1 for anammox and denitrification, respectively). During fall, denitrification was the only contributor to the observed nitrogen deficit (894 nmol N2 L-1 d-1). Interestingly, a substantial increase in the rates of denitrification (∼ 1200 nmol N2 L-1 d-1) and dark 13C assimilation were observed after the addition of H2S, indicating an autotrophic contribution to denitrification, which could be fueled in situ by H2S emitted from sediments or produced in the water column. The observed patterns seem to be controlled (stimulated or inhibited) by the availability of oxygen, organic matter, andH2S. This study establishes the magnitude and co-occurrence of the different processes responsible for N removal in the coastal upwelling system of central Chile. This linkage of the nitrogen, carbon, and sulfur cycles is relevant to a global climate change scenario.1865–1878659
Dinámica del Clima2014Garreaud, R., Gabriela Nicora, M., Bürgesser, R. E., & Ávila, E. E.Lightning in Western PatagoniaJournal of Geophysical Research: Atmospheres10.1002/2013JD021160 the basis of 8-years (2005-2012) of stroke data from the World Wide Lightning Location Network we describe the spatial distribution and temporal variability of lightning activity over Western Patagonia. This region extends from ∼40°S to 55°S along the west coast of South America, is limited to the east by the austral Andes, and features a hyper-humid, maritime climate. Stroke density exhibits a sharp maximum along the coast of southern Chile. Although precipitation there is largely produced by cold nimbostratus, days with more than one stroke occur up to a third of the time somewhere along the coastal strip. Disperse strokes are also observed off southern Chile. In contrast, strokes are virtually nonexistent over the austral Andes - where precipitation is maximum - and farther east over the dry lowlands of Argentina. Atmospheric reanalysis and satellite imagery are used to characterize the synoptic environment of lightning-producing storms, exemplified by a case study and generalized by a compositing analysis. Lightning activity tends to occur when Western Patagonia is immersed in a pool of cold air behind a front that has reached the coast at ∼40°S. Under these circumstances, midlevel cooling occurs before and is more prominent than near-surface cooling, leading to a weakly unstable postfrontal condition. Forced uplift of the strong westerlies impinging on the coastal mountains can trigger convection and produces significant lightning activity in this zone. Farther offshore, large-scale ascent near the cyclone's center may lift near-surface air parcels, fostering shallow convection and dispersing lightning activity. Key Points Significant lightning activity occurs in Western Patagonia Lightning storms develop under a cold, weakly unstable postfrontal condition Topography and ocean conditions favor lightning activity in Western Patagonia. © 2014. American Geophysical Union. All Rights Reserved.4471–44858119
Modelación y Sistemas de Observación2014Huneeus, N., Boucher, O., Alterskjaer, K., Cole, J. N. S., Curry, C. L., Ji, D., … Yoon, J.-H.Forcings and feedbacks in the GeoMIP ensemble for a reduction in solar irradiance and increase in CO 2Journal of Geophysical Research: Atmospheres10.1002/2013JD021110 effective radiative forcings (including rapid adjustments) and feedbacks associated with an instantaneous quadrupling of the preindustrial CO2 concentration and a counterbalancing reduction of the solar constant are investigated in the context of the Geoengineering Model Intercomparison Project (GeoMIP). The forcing and feedback parameters of the net energy flux, as well as its different components at the top-of-atmosphere (TOA) and surface, were examined in 10 Earth System Models to better understand the impact of solar radiation management on the energy budget. In spite of their very different nature, the feedback parameter and its components at the TOA and surface are almost identical for the two forcing mechanisms, not only in the global mean but also in their geographical distributions. This conclusion holds for each of the individual models despite intermodel differences in how feedbacks affect the energy budget. This indicates that the climate sensitivity parameter is independent of the forcing (when measured as an effective radiative forcing). We also show the existence of a large contribution of the cloudy-sky component to the shortwave effective radiative forcing at the TOA suggesting rapid cloud adjustments to a change in solar irradiance. In addition, the models present significant diversity in the spatial distribution of the shortwave feedback parameter in cloudy regions, indicating persistent uncertainties in cloud feedback mechanisms. ©2014. American Geophysical Union. All Rights Reserved.5226–52399119
Dimensión Humana2014Iverson, L., Echeverría, C., Nahuelhual, L., & Luque, S.Ecosystem services in changing landscapes: An introductionLandscape Ecology10.1007/s10980-014-9993-2 concept of ecosystem services from landscapes is rapidly gaining momentum as a language to communicate values and benefits to scientists and lay alike. Landscape ecology has an enormous contribution to make to this field, and one could argue, uniquely so. Tools developed or adapted for landscape ecology are being increasingly used to assist with the quantification, modelling, mapping, and valuing of ecosystem services. Several of these tools and methods encased therein are described among the eleven papers presented in this special issue, and their application has the potential to facilitate the management and promotion of services within ecosystems. Papers are associated with each of the four key categories of services that ecosystems provide to humans: supporting, provisioning, regulating, and cultural. The papers represent work conducted in eleven different countries, especially from South America. Each carries a unique approach to address a particular question pertaining to a particular set of ecosystem services. These studies are designed to inform and improve the economic, environmental and social values of the ecosystem services. This knowledge should help to develop new management alternatives for sustaining and planning ecosystems and the services they provide at different scales in space and time. We believe that these papers will create interest and inform management of some potential methods to evaluate ecosystem services at the landscape level with an integrative approach, offering new tools for management and conservation. © 2014 Springer Science+Business Media Dordrecht (outside the USA).181–186229
Dinámica del Clima2014Jara, I. A., & Moreno, P. I.Climatic and disturbance influences on the temperate rainforests of northwestern Patagonia (40 °S) since ∼14,500 cal yr BPQuaternary Science Reviews10.1016/j.quascirev.2014.01.024 present a detailed record from Lago Pichilafquén to unravel the vegetation, climate and disturbance history of the lowlands of northwestern Patagonia (40°S) since 14,500calyrBP. The presence of 30 tephras throughout the record attest for the proximity of the site to active volcanic centres and allows assessment of the role of volcanic disturbance on past vegetation and fire regime shifts. We interpretalternations in dominance between North Patagonian and Valdivian rainforests driven by changes in temperature and precipitation of westerly origin at multi-millennial and millennial timescales. These trends were punctuated by centennial-scale changes, most of which were coeval with or immediately followed the deposition of tephras and/or paleofires. We identify departures of the local vegetation from the regional trend between 2400 and 7100calyrBP, which we interpret as a response of rainforest vegetation and local fire regimes to the disturbance effect of tephra deposition near Lago Pichilafquén. We also find that volcanic disturbance promoted consistent increases in Eucryphia/Caldcluvia within 30 years and paleofires between 60 and 120years following tephra deposition. Comparisons with palynological records having similar span, time resolution and age control suggest that regional climate has played a central role on the establishment, composition and maintenance of temperate rainforests. This influence is overprinted by disturbance regimes at the local and landscape level, driving divergences and heterogeneity especially at times of relatively weak climatic forcing. © 2014 Elsevier Ltd.217–22890
Biogeoquímica2014Kerber, F., Querel, R. R., Rondanelli, R., Hanuschik, R., van den Ancker, M., Cuevas, O., … Czekala, H.An episode of extremely low precipitable water vapour over Paranal observatoryMonthly Notices of the Royal Astronomical Society10.1093/mnras/stt2404 report on an episode of extremely low precipitable water vapour (PWV) of approximately 0.1mm with a duration of more than 12 h at European Southern Observatory's Paranal observatory [2635m above sea level (asl)]. Such conditions are more commonly expected at sites at much higher altitude such as ALMA on the Chajnantor plateau (5000m asl) or otherwise particularly dry sites such as locations in Antarctica. We provide a full account ofthe measurements of PWV and other relevant atmospheric parameters. An explanation of the observed conditions is given in terms of the prevailing meteorological pattern. Based on statistical evidence from measurements by VLT spectrographs (UVES and CRIRES) covering more than a decade, we find that PWV <0.2mm can be expected on less than 1 per cent of the nights, while <0.5mm is encountered on 6-7 nights per year (≈2 per cent). The scientificpotential of using this small but significant fraction of observing time is illustrated in the context of service modeSociety. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.247–2551439
Modelación y Sistemas de Observación2014Lamy, F., Gersonde, R., Winckler, G., Esper, O., Jaeschke, A., Kuhn, G., Lambert, F. … Kilian, R.Increased dust deposition in the Pacific Southern Ocean during glacial periods.Science (New York, N.Y.)10.1126/science.1245424 deposition in the Southern Ocean constitutes a critical modulator of past global climate variability, but how it has varied temporally and geographically is underdetermined. Here, we present data sets of glacial-interglacial dust-supply cycles from the largest Southern Ocean sector, the polar South Pacific, indicating three times higher dust deposition during glacial periods than during interglacials for the past million years. Although the most likely dust source for the South Pacific is Australia and New Zealand, the glacial-interglacial pattern and timing of lithogenic sediment deposition is similar to dust records from Antarctica and the South Atlantic dominated by Patagonian sources. These similarities imply large-scale common climate forcings, such as latitudinal shifts of the southern westerlies and regionally enhanced glaciogenic dust mobilization in New Zealand and Patagonia.403–76169343
Dinámica del Clima2014Mechoso, C. R., Wood, R., Weller, R., Bretherton, C. S., Clarke, A. D., Coe, H., Garreaud, R. D., … Zuidema, P.Ocean–Cloud–Atmosphere–Land Interactions in the Southeastern Pacific: The VOCALS ProgramBulletin of the American Meteorological Society10.1175/BAMS-D-11-00246.1 Variability of American Monsoon Systems (VAMOS) Ocean-Cloud-Atmosphere- Land Study (VOCALS) is an international research program focused upon improved understanding and modeling of the southeast Pacific (SEP) climate system on diurnal to inter annual time scales. The SEP is characterized by strong coastal ocean upwelling, the coldest sea surface temperatures (SST) at comparable latitudes, the planet's most extensive subtropical stratocumulus deck, and a high and steep cordillera to the east. The VOCALS program is built on several research activities in SEP climate research (Mechoso and Wood 2010). The preceding Eastern Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC) provided important insight on the intertropical convergence zone (ITCZ)/cold-tongue complex and marine boundary layer (MBL) clouds over the SEP.357–375395
Biogeoquímica2014Mohtadi, M., Prange, M., Oppo, D. W., de Pol-Holz, R., Merkel, U., Zhang, X., … Lückge, A.North Atlantic forcing of tropical Indian Ocean climate.Nature10.1038/nature13196 response of the tropical climate in the Indian Ocean realm to abrupt climate change events in the North Atlantic Ocean is contentious. Repositioning of the intertropical convergence zone is thought to have been responsible for changes in tropical hydroclimate during North Atlantic cold spells, but the dearth of high-resolution records outside the monsoon realm in the Indian Ocean precludes a full understanding of this remote relationship and its underlying mechanisms. Here we show that slowdowns of the Atlantic meridional overturning circulation during Heinrich stadials and the Younger Dryas stadial affected the tropical Indian Ocean hydroclimate through changes to the Hadley circulation including a southward shift in the rising branch (the intertropical convergence zone) and an overall weakening over the southern Indian Ocean. Our results are based on new, high-resolution sea surface temperature and seawater oxygen isotope records of well-dated sedimentary archives from the tropical eastern Indian Ocean for the past 45,000 years, combined with climate model simulations of Atlantic circulation slowdown under Marine Isotope Stages 2 and 3 boundary conditions. Similar conditions in the east and west of the basin rule out a zonal dipole structure as the dominant forcing of the tropical Indian Ocean hydroclimate of millennial-scale events. Results from our simulations and proxy data suggest dry conditions in the northern Indian Ocean realm and wet and warm conditions in the southern realm during North Atlantic cold spells.76–807498509
Dinámica del Clima; Modelación y Sistemas de Observación; Servicios Ecosistémicos2014Moreno, P. I., Vilanova, I., Villa-Martínez, R., Garreaud, R., Rojas, M., & de Pol-Holz, R.Southern Annular Mode-like changes in southwestern Patagonia at centennial timescales over the last three millennia.Nature communications10.1038/ncomms5375 twentieth-century instrumental records reveal a persistent southward shift of the Southern Westerly Winds during austral summer and autumn associated with a positive trend of the Southern Annular Mode (SAM) and contemporaneous with glacial recession, steady increases in atmospheric temperatures and CO2 concentrations at a global scale. However, despite the clear importance of the SAM in the modern/future climate, very little is known regarding its behaviour during pre-Industrial times. Here we present a stratigraphic record from Lago Cipreses (51°S), southwestern Patagonia, that reveals recurrent ∼200-year long dry/warm phases over the last three millennia, which we interpret as positive SAM-like states. These correspond in timing with the Industrial revolution, the Mediaeval Climate Anomaly, the Roman and Late Bronze Age Warm Periods and alternate with cold/wet multi-centennial phases in European palaeoclimate records. We conclude that SAM-like changes at centennial timescales in southwestern Patagonia represent in-phase interhemispheric coupling of palaeoclimate over the last 3,000 years through atmospheric teleconnections.43755
Dinámica del Clima; Servicios Ecosistémicos2014Muñoz, A. A., Barichivich, J., Christie, D. A., Dorigo, W., Sauchyn, D., González-Reyes, Á., … González, M. E.Patterns and drivers of Araucaria araucana forest growth along a biophysical gradient in the northern Patagonian Andes: Linking tree rings with satellite observations of soil moistureAustral Ecology10.1111/aec.12054 araucana (Araucaria) is a long-lived conifer growing along a sharp west-east biophysical gradient in the Patagonian Andes. The patterns and climate drivers of Araucaria growth have typically been documented on the driest part of the gradient relying on correlations with meteorological records, but the lack of in situ soil moisture observations has precluded an assessment of the growth responses to soil moisture variability. Here, we use a network of 21 tree-ring width chronologies to investigate the spatiotemporal patterns of tree growth through the entire gradient and evaluate their linkages with regional climate and satellite-observed surface soil moisture variability. We found that temporal variations in tree growth are remarkably similar throughout the gradient and largely driven by soil moisture variability. The regional spatiotemporal pattern of tree growth was positively correlated with precipitation (r=0.35 for January 1920-1974; P<0.01) and predominantly negatively correlated with temperature (r=-0.38 for January-March 1920-1974; P<0.01) during the previous growing season. These correlations suggest a temporally lagged growth response to summer moisture that could be associated with known physiological carry-over processes in conifers and to a response to moisture variability at deeper layers of the rooting zone. Notably, satellite observations revealed a previously unobserved response of Araucaria growth to summer surface soil moisture during the current rather than the previous growing season (r=0.65 for 1979-2000; P<0.05). This new response has a large spatial footprint across the mid-latitudes of the South American continent (35°-45°S) and highlights the potential of Araucaria tree rings for palaeoclimatic applications. The strong moisture constraint on tree growth revealed by satellite observations suggests that projected summer drying during the coming decades may result in regional growth declines in Araucaria forests and other water-limited ecosystems in the Patagonian Andes. © 2013 Ecological Society of Australia.158–169239
Dimensión Humana2014Nahuelhual, L., Carmona, A., Laterra, P., Barrena, J., & Aguayo, M.A mapping approach to assess intangible cultural ecosystem services: The case of agriculture heritage in Southern ChileEcological Indicators10.1016/j.ecolind.2014.01.005 and mapping of cultural ecosystem services (CES) represents a significant gap in ecosystem service research. A GIS-based methodological framework was developed and applied to map agricultural heritage (AH), understood as a non-divisible combination of three cultural services (dimensions, D): the heritage value associated to a culturally significant species (i.e. Chiloé native potato) (D1); the traditional systems of knowledge of AH keepers (D2); and the social relations among them (D3). The final aim of the study was to provide indicators of the "final" service (AHi, measured in a 0-100 point scale) and its benefits (AHB, measured in US$/ha), capable to display areas where high value farmland was located. In essence, AHi comprised a set of biocultural variables validated and weighted by expert opinion. The experts gave the maximum importance to 5 variables: number of native potato varieties cultivated (D1), use of own seed (D1), form in which cultivation knowledge was acquired by the keeper (D2), exchange of own seed (D3), and number of other potato keepers known (D3). In turn, AHB reflected society's willingness to pay for the nonmaterial benefits of AH conservation. Since these benefits "propagate" across space extending from local to unknown and distant beneficiaries, and the aim was to identify the most valuable areas for their capacity to satisfy a potential demand, AHB was spatialized following the approach of "ascribing" the potential benefits to their "point of provision". Thus the highest values of AHi coincided with the highest values of AHB (US$10.64-8.64 ha-1) a comprised 5608 ha of the landscape, and similarly the lowest values of AHi matched the lowest values of AHB (US$1.69-0.18 ha-1) comprising 13,070 ha of the landscape. © 2014 Elsevier Ltd.90–10140
Dinámica del Clima2014Pesce, O. H., & Moreno, P. I.Vegetation, fire and climate change in central-east Isla Grande de Chiloé (43°S) since the Last Glacial Maximum, northwestern PatagoniaQuaternary Science Reviews10.1016/j.quascirev.2014.02.021 present a detailed record from Lago Lepué to examine vegetation, climate and fire-regime changes since the Last Glacial Maximum (LGM) in central-east Isla Grande de Chiloé (43°S), northwestern Patagonia. Precipitation in this region correlates with the intensity of the southern westerly winds (SWW), allowing reconstruction of past SWW behavior through precipitation-sensitive sensors. Recession from the LGM glacier margins exposed the central-east sector of Isla Grande de Chiloé by 17,800calyrBP, followed by the immediate colonization of pioneer cold-resistant herbs/shrubs and rapid establishment of closed-canopy Nothofagus forests by 17,000calyrBP. Broad-leaved temperate rainforests have persisted since then with compositional changes driven by changes in temperature, hydrologic balance and disturbance regimes. We detect low lake levels and enhanced fire activity between 800-2000, 4000-4300, ∼8000-11,000 and 16,100-17,800calyrBP, implying southward shifts and/or weaker SWW flow that alternated with cold, humid phases with muted fire activity. Covariation in paleoclimate trends revealed by the Lago Lepué record with tropical and Antarctic records since the LGM, suggests that the SWW have been a highly dynamic component of the climate system capable of linking climate changes from low- and high-southern latitudes during the Last Glacial termination and the current interglacial. © 2014 Elsevier Ltd.143–15790
Dinámica del Clima2014Rahn, D. A., & Garreaud, R.A synoptic climatology of the near-surface wind along the west coast of South AmericaInternational Journal of Climatology10.1002/joc.3724 wind along the west coast of South America is equatorward, driven by the southeast Pacific anticyclone. The wind induces strong coastal upwelling that supports one of the most important fisheries in the world. This region lacks a dense network of in situ observations, so the high resolution (0.313°) NCEP Climate Forecast System Reanalysis is used here to present a synoptic climatology of the coastal wind along the Chile/Peru coast. Covariability between the alongshore pressure gradient and alongshore wind, which was previously identified for synoptic time scales near central Chile, is generalized for the whole coast and over annual time scales. Particular attention is paid to three prominent upwelling regions: Pisco (14.8°S), Punta Lengua de Vaca (30.0°S), and Punta Lavapie (36.4°S). Previous work has identified local maxima at these points but these are embedded in a broader low-level jet that exhibits a marked seasonal cycle of strong wind days due to the migration of the anticyclone and is associated with a shift of both the mean wind and a more frequent recurrence of strong wind events. Alongshore wind near Pisco is normally distributed year-round with a seasonal shift in the mean. Larger variability in the mean and distribution is found at Lavapie, associated with the seasonal change in storm tracks. The synoptic evolution that drives high-wind events at each location is characterized. A midlevel trough and surface cyclone precede wind maxima at each location and are followed by strong midlevel ridging and a strengthened surface anticyclone. © 2013 Royal Meteorological Society780–792334
Dimensión Humana2014Romero-Lankao, P., Hughes, S., Qin, H., Hardoy, J., Rosas-Huerta, A., Borquez, R., & Lampis, A.Scale, urban risk and adaptation capacity in neighborhoods of Latin American citiesHabitat International10.1016/j.habitatint.2013.12.008 urbanites are vulnerable to a suite of risks that climate change might aggravate (e.g., mortality from extreme temperatures and property damages from floods), urban populations and decision makers may also be positioned to most effectively respond to such risks. Research is needed however, exploring both the multilevel factors and processes that determine urban risk and the complex pathways from hazards to impacts, and from perceptions and coping responses to adaptation. This paper analyzes whether and under what circumstances urban populations experience risk in selected Latin American neighborhoods of Bogotá, Buenos Aires, Mexico and Santiago; it assesses their adaptation capacity, i.e., ability to perceive and respond to hazards. It finds that urban risk depends on scale: hazards, adaptation capacities, responses and their underlying societal and physical drivers vary across urban households, neighborhoods and cities. Informality is a state of regulatory flux, where access to land and livelihood options cannot be fixed and mapped according to any prearranged sets of laws and planning mechanisms, that has a profound influence on risk and adaptation capacities across scales. For instance, informality becomes the site of considerable state power where some forms of growth in risk-prone areas enjoy state sanction while others are criminalized. The informal status becomes both a source of stigmatization that disempowers informal neighborhoods and a systemic determinant of lack of access to assets and options for adaptation capacity.224–23542
Servicios Ecosistémicos2014Romero-Mieres, M., González, M. E., & Lara, A.Recuperación natural del bosque siempreverde afectado por tala rasa y quema en la Reserva Costera Valdiviana, ChileBosque (Valdivia)10.4067/S0717-92002014000300001 study aimed at understanding the natural recovery of the evergreen forest a decade after being affected by clearcutting and burning, in a site located in the Valdivian Coastal Reserve (39°56’ S-73°40’ W). A total of 27 circular (50.2 m2) plots with eight subplots each were established. Floristic composition was recorded and quantitative, diametric and age structures were determined. The results show a richness of 77 vascular species (84.4% natives), with Lophosoria quadripinnata presenting the highest relative cover (20.7%). The presence of hemicryptophytes (35%) indicates human intervention in the place. Trees were the main form of growth, being Drimys winteri, Saxegothaea conspicua and Amomyrtus luma the species with higher plant density. The latter two species growing under Chusquea macrostachya and Lophosoria quadripinnata cover. Drimys winteri and Embothrium coccineum were established immediately after the anthropogenic disturbance of clearcutting and burning, confirming the pioneering character of these two species after highly severe disturbances. Regeneration of Nothofagus nitida was scarce in the area, probably associated with low availability and seed dispersal capacity from surrounding forests. Understanding the early response of evergreen forests affected by anthropogenic disturbance is very important for assisting and guiding the ecological restoration of these forest ecosystems.257–267335
Modelación y Sistemas de Observación2014Shaffer, G.Formulation, calibration and validation of the DAIS model (version 1), a simple Antarctic ice sheet model sensitive to variations of sea level and ocean subsurface temperatureGeoscientific Model Development10.5194/gmd-7-1803-2014 DCESS (Danish Center for Earth System Science) Antarctic Ice Sheet (DAIS) model is presented. Model hindcasts of Antarctic ice sheet (AIS) sea level equivalent are forced by reconstructed Antarctic temperatures, global mean sea level and high-latitude, ocean subsurface temperatures, the latter calculated using the DCESS model forced by reconstructed global mean atmospheric temperatures. The model is calibrated by comparing such hindcasts for different model configurations with paleoreconstructions of AIS sea level equivalent from the last interglacial, the last glacial maximum and the mid-Holocene. The calibrated model is then validated against present estimates of the rate of AIS ice loss. It is found that a high-order dependency of ice flow at the grounding line on water depth there is needed to capture the observed response of the AIS at ice age terminations. Furthermore, it is found that a dependency of this ice flow on ocean subsurface temperature by way of ice shelf demise and a resulting buttressing decrease is needed to explain the contribution of the AIS to global mean sea level rise at the last interglacial. When forced and calibrated in this way, model hindcasts of the rate of present-day AIS ice loss agree with recent, data-based estimates of this ice loss rate. © Author(s) 2014.1803–181847
Servicios Ecosistémicos2014Ulrich, W., Soliveres, S., Maestre, F. T., Gotelli, N. J., Quero, J. L., Delgado-Baquerizo, M., Gómez-González, S., … Zaady, E.Climate and soil attributes determine plant species turnover in global drylands.Journal of biogeography10.1111/jbi.12377 Geographic, climatic, and soil factors are major drivers of plant beta diversity, but their importance for dryland plant communities is poorly known. This study aims to: i) characterize patterns of beta diversity in global drylands, ii) detect common environmental drivers of beta diversity, and iii) test for thresholds in environmental conditions driving potential shifts in plant species composition. LOCATION: 224 sites in diverse dryland plant communities from 22 geographical regions in six continents. METHODS: Beta diversity was quantified with four complementary measures: the percentage of singletons (species occurring at only one site), Whittake's beta diversity (β(W)), a directional beta diversity metric based on the correlation in species occurrences among spatially contiguous sites (β(R(2))), and a multivariate abundance-based metric (β(MV)). We used linear modelling to quantify the relationships between these metrics of beta diversity and geographic, climatic, and soil variables. RESULTS: Soil fertility and variability in temperature and rainfall, and to a lesser extent latitude, were the most important environmental predictors of beta diversity. Metrics related to species identity (percentage of singletons and β(W)) were most sensitive to soil fertility, whereas those metrics related to environmental gradients and abundance ((β(R(2))) and β(MV)) were more associated with climate variability. Interactions among soil variables, climatic factors, and plant cover were not important determinants of beta diversity. Sites receiving less than 178 mm of annual rainfall differed sharply in species composition from more mesic sites (> 200 mm). MAIN CONCLUSIONS: Soil fertility and variability in temperature and rainfall are the most important environmental predictors of variation in plant beta diversity in global drylands. Our results suggest that those sites annually receiving ∼ 178 mm of rainfall will be especially sensitive to future climate changes. These findings may help to define appropriate conservation strategies for mitigating effects of climate change on dryland vegetation.2307–23191241
Dinámica del Clima2014Viale, M., & Garreaud, R.Summer Precipitation Events over the Western Slope of the Subtropical AndesMonthly Weather Review10.1175/MWR-D-13-00259.1 [December-February (DJF)] precipitation over the western slopes of the subtropical Andes (32°-368°) accounts for less than 10% of the annual accumulation, but it mostly occurs as rain and may trigger landslides leading to serious damages. Based on 13 year of reanalysis, in situ observations, and satellite imagery, a synoptic climatology and physical diagnosis reveal two main weather types lead to distinct precipitation systems. The most frequent type (̃80% of the cases) occurs when a short-wave midlevel trough with weak winds and thermally driven mountain winds favor the development of convective precipitation during the daytime. The trough progresses northwest of a long-lasting warm ridge, which produces low-level easterly airflow that enhances its buoyancy as it moves over the arid land of western Argentina toward the Andes. The weak winds aloft facilitate the penetration of the moist easterly flow into the Andes. Midlevel flow coming from the west side of the Andes is decoupled from the low-level maritime air by a temperature inversion, and thus provides little moisture to support precipitation. The less frequent type (̃20% of the cases) occurs when a deep midlevel trough and strong westerly flow produces stratiform precipitation. This type has a baroclinic nature akin to winter storms, except that they are rare in summer and there is no evidence of a frontal passage at low levels. The lifting and cooling ahead of the trough erode the typical temperature inversion over the Pacific coast, and thus allows upslope transport of low-level marine air by the strong westerlies forming a precipitating cloud cap on the western slope of the Andes. © 2014 American Meteorological Society.1074–10923142
Biogeoquímica2015Alcamán, M. E., Fernandez, C., Delgado-Huertas, A., Bergman, B., & Díez, B.The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial matThe ISME Journal10.1038/ismej.2015.63 from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011-2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69-38 °C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of (15)N2) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58 °C to 46 °C, with maximum daily rates of 600 nmol C2H4 cm(-2) per day and 94.1 nmol N cm(-2) per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed ∼3 g N m(-2) per year and 27 g C m(-2) per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.2290–2303109
Dimensión Humana2015Aldunce, P., Beilin, R., Howden, M., & Handmer, J.Resilience for disaster risk management in a changing climate: Practitioners’ frames and practicesGlobal Environmental Change10.1016/j.gloenvcha.2014.10.010 is a growing use of resilience ideas within the disaster risk management literature and policy domain. However, few empirical studies have focused on how resilience ideas are conceptualized by practitioners, as they implement them in practice. Using Hajer's 'social-interactive discourse theory' this research contributes to the understanding of how practitioners frame, construct and make sense of resilience ideas in the context of changes in institutional arrangements for disaster risk management that explicitly include the resilience approach and climate change considerations. The case study involved the roll out of the Natural Disaster Resilience Program in Queensland, Australia, and the study involved three sites in Queensland. The methods used were observation of different activities and the physical sites, revision of documents related to the Natural Disaster Resilience Program and in-depth semi-structured interviews with key informants, all practitioners who had direct interaction with the program. The research findings show that practitioners construct the meaning of disaster resilience differently, and these are embedded in diverse storylines. Within these storylines, practitioners gave different interpretations and emphasis to the seven discourse categories that characterized their resilience discourse. Self-reliance emerged as one of the paramount discourse categories but we argue that caution needs to be used when promoting values of self-reliance. If the policy impetus is a focus on learning, research findings indicate it is also pertinent to move from experiential learning toward social learning. The results presented in this study provide helpful insights to inform policy design and implementation of resilience ideas in disaster risk management and climate change, and to inform theory.1–1130
Dinámica del Clima2015Álvarez, C., Veblen, T. T., Christie, D. A., & González-Reyes, Á.Relationships between climate variability and radial growth of Nothofagus pumilio near altitudinal treeline in the Andes of northern Patagonia, ChileForest Ecology and Management10.1016/j.foreco.2015.01.018 warming is expected to enhance radial tree growth at alpine treeline sites worldwide. We developed a well-replicated tree-ring chronology from Nothofagus pumilio near treeline in a high precipitation climate on Choshuenco Volcano (40°S) in Chile to examine: (a) variation in tree radial growth in relation to interannual climatic variability; and (b) relationships of radial growth to variability in El Niño Southern Oscillation (ENSO) and the Antarctic Oscillation (AAO) at interannual and decadal time scales. A tree-ring chronology based on 99 tree-ring series from 80 N. pumilio trees near treeline showed a high series intercorrelation (0.48) indicating a strong common environmental signal. Radial growth is negatively correlated with precipitation in late spring (November–December). Temperature and tree growth are positively correlated during late spring and early summer (November–January). Interannual variability in both seasonal climate and in tree growth is strongly teleconnected to ENSO and AAO variability. Radial growth of N. pumilio in this humid high-elevation forest does not show a positive trend over the past half century as predicted from global treeline theory and broadscale warming in the Patagonian-Andean region. Instead, tree growth increased sharply from the 1960s to a peak in the early 1980s but subsequently declined for c. 30years to its lowest level in >100years. The shift to higher radial growth after c. 1976 coincides with a shift towards warmer sea surface temperatures in the tropical Pacific which in turn are associated with warmer growing season temperatures. The decline in tree growth since the mid-1990s is coincident with the increasingly positive phase of the AAO and high spring precipitation periods associated with El Niño conditions. The recent shift towards reduced growth of N. pumilio at this humid high-elevation site coincident with rising AAO mirrors the reduced tree growth beginning in the 1960s for trees growing in relatively xeric, lower elevation sites throughout the Patagonian-Andean region. The current study indicates that N. pumilio growth response in humid high-elevation environments to recent broad-scale warming has been non-linear, and that AAO and ENSO are key climatic forcings of tree growth variability.112–121342
Modelación y Sistemas de Observación2015Arias, P. A., Fu, R., Vera, C., & Rojas, M.A correlated shortening of the North and South American monsoon seasons in the past few decadesClimate Dynamics10.1007/s00382-015-2533-1 observational analysis shows that the wet seasons of the American monsoon systems have shortened since 1978 due to correlated earlier retreats of the North American monsoon (NAM) and late onsets of the southern Amazon wet season, an important part of the South American monsoon (SAM). These changes are related to the combination of the global sea surface temperature (SST) warming mode, the El Niño-Southern Oscillation (ENSO), the Atlantic Multidecadal Oscillation (AMO), the westward shift of the North Atlantic subtropical high (NASH), and the enhancement of Pacific South American and Pacific North American wave train patterns, which induces variations of the regional circulation at interannual and decadal scales. The joint contributions from these forcing factors are associated with a stronger and more equatorward regional Hadley cell, which enhances convergence towards the equator, strengthening and possibly delaying the retreat of the tropical part of the NAM. This in turn accelerates the demise of the northern NAM and delays the reversal of the cross-equatorial flow over South America, reducing moisture transport to the SAM and delaying its onset. In addition, the thermodynamic response to warming appears to cause local drier land conditions over both regions, reinforcing the observed changes in these monsoons. Although previous studies have identified the isolated influence of the regional Hadley cell, ENSO, AMO, global SST warming, and NASH on the NAM, the correlated changes between NAM and SAM through variations of the cross-equatorial flow had not been established before.3183–320311-1245
Dinámica del Clima2015Boisier, J. P., Ciais, P., Ducharne, A., & Guimberteau, M.Projected strengthening of Amazonian dry season by constrained climate model simulationsNature Climate Change10.1038/nclimate2658 vulnerability of Amazonian rainforest, and the ecological services it provides, depends on an adequate supply of dry-season water, either as precipitation or stored soil moisture. How the rain-bearing South American monsoon will evolve across the twenty-first century is thus a question of major interest. Extensive savanization, with its loss of forest carbon stock and uptake capacity, is an extreme although very uncertain scenario. We show that the contrasting rainfall projections simulated for Amazonia by 36 global climate models (GCMs) can be reproduced with empirical precipitation models, calibrated with historical GCM data as functions of the large-scale circulation. A set of these simple models was therefore calibrated with observations and used to constrain the GCM simulations. In agreement with the current hydrologic trends, the resulting projection towards the end of the twenty-first century is for a strengthening of the monsoon seasonal cycle, and a dry-season lengthening in southern Amazonia. With this approach, the increase in the area subjected to lengthy - savannah-prone - dry seasons is substantially larger than the GCM-simulated one. Our results confirm the dominant picture shown by the state-of-the-art GCMs, but suggest that the â € model democracy'view of these impacts can be significantly underestimated.656–66075
Biogeoquímica; Dinámica del Clima; Modelación y Sistemas de Observación2015Boisier, J. P., Rondanelli, R., Garreaud, R., & Muñoz, F.Anthropogenic and natural contributions to the Southeast Pacific precipitation decline and recent mega-drought in central ChileGeophysical Research Letters10.1002/2015GL067265 large uncertainties in the precipitation response to greenhouse gas forcing, the Southeast Pacific drying stands out as a robust signature within climate models. A precipitation decline, of consistent direction but of larger amplitude than obtained in simulations with historical climate forcing, has been observed in central Chile since the late 1970s. To attribute the causes of this trend, we analyze local rain gauge data and contrast them to a large ensemble of both fully coupled and sea surface temperature-forced simulations. We show that in concomitance with large-scale circulation changes, the Pacific Decadal Oscillation explains about half of the precipitation trend observed in central Chile. The remaining fraction is unlikely to be driven exclusively by natural phenomena but rather consistent with the simulated regional effect of anthropogenic climate change. We particularly estimate that a quarter of the rainfall deficit affecting this region since 2010 is of anthropogenic origin. An increased persistence and recurrence of droughts in central Chile emerges then as a realistic scenario under the current socioeconomic pathway.413–421143
Modelación y Sistemas de Observación2015Bozkurt, D., Sen, O., & Hagemann, S.Projected river discharge in the Euphrates–Tigris Basin from a hydrological discharge model forced with RCM and GCM outputsClimate Research10.3354/cr01268 hydrological discharge (HD) model of Max Planck Institute for Meteorology is forced by a variety of climate model datasets to investigate the future of discharge in the Euphrates-Tigris Basin. The data include daily time series of surface runoff and sub-surface runoff outputs of 2 global climate models (GCMs) (the SRES A1B scenario simulation of ECHAM5/MPIOM and the RCP 4.5 scenario simulation of MPI-ESM-LR) and the dynamically downscaled outputs of ECHAM5/MPIOM and NCAR-CCSM3 scenario (SRES A1FI, A2 and B1) simulations. The suite of simulations enables a comprehensive analysis of the projected river discharge, and allows a comparison between CMIP5 simulations of MPI-ESM-LR and CMIP3 results from its predecessor ECHAM5/MPIOM on a basin scale. We demonstrate that HD simulations forced with relatively low-resolution GCM outputs are not good at reproducing the seasonal cycle of discharge, which is typically characterized by less flow in the peak season and an earlier peak in annual discharge. Simulations forced with the MPI-ESM-LR yield more robust information on the annual cycle and timing of the annual peak discharge than ECHAM5-forced simulations. In contrast to GCM-forced simulations, high-resolution RCM-forced simulations reproduce the annual cycle of discharge reasonably well; however, overestimation of discharge during the cold season and bias in the timing of springtime snowmelt peaks persist in the RCM-forced simulations. Different RCM-forced scenario simulations indicate substantial decreases in mean annual discharge for the Euphrates and Tigris Rivers by the end of the century, ranging from 19-58%. Significant temporal shifts to earlier days (3-5 wk by the end of the 21st century) in the center time of the discharges are also projected for these rivers. As the basin is considered water-stressed and the region is strongly influenced by water-scarcity events, these unfavorable changes may potentially increase water disputes among the basin countries.131–147262
Dinámica del Clima; Modelación y Sistemas de Observación2015Bravo, C., Rojas, M., Anderson, B., Mackintosh, A. N., Sagredo, E., & Moreno, P. I.Modelled glacier equilibrium line altitudes during the mid-Holocene in the southern mid-latitudesClimate of the Past10.5194/cp-11-1575-2015 behaviour during the mid-Holocene (MH, 6000 years BP) in the Southern Hemisphere provides observational data to constrain our understanding of the origin and propagation of palaeoclimate signals. In this study we examine the climatic forcing of glacier response in the MH by evaluating modelled glacier equilibrium line altitudes (ELAs) and climatic conditions during the MH compared with pre-industrial time (PI, year 1750). We focus on the middle latitudes of the Southern Hemisphere, specifically Patagonia and the South Island of New Zealand. Climate conditions for the MH were obtained from PMIP2 model simulations, which in turn were used to force a simple glacier mass balance model to simulate changes in ELA. In Patagonia, the models simulate colder conditions during the MH in austral summer (-0.2 °C), autumn (-0.5 °C), and winter (-0.4), and warmer temperatures (0.2 °C) during spring. In the Southern Alps the models show colder MH conditions in autumn (-0.7 °C) and winter (-0.4 °C), warmer conditions in spring (0.3 °C), and no significant change in summer temperature. Precipitation does not show significant changes but exhibits a seasonal shift, with less precipitation from April to September and more precipitation from October to April during the MH in both regions. The mass balance model simulates a climatic ELA that is 15-33 m lower during the MH compared with PI conditions. We suggest that the main causes of this difference are driven mainly by colder temperatures associated with the MH simulation. Differences in temperature have a dual effect on glacier mass balance: (i) less energy is available for ablation during summer and early autumn and (ii) lower temperatures cause more precipitation to fall as snow rather than rain in late autumn and winter, resulting in more accumulation and higher surface albedo. For these reasons, we postulate that the modelled ELA changes, although small, may help to explain larger glacier extents observed by 6000 years BP in South America and New Zealand.1575–15861111
Servicios Ecosistémicos2015Cabezas, J., Galleguillos, M., Valdés, A., Fuentes, J. P., Pérez, C., & Perez-Quezada, J. F.Evaluation of impacts of management in an anthropogenic peatland using field and remote sensing dataEcosphere10.1890/ES15-00232.1 are a type of wetland characterized by the accumulation of organic matter, called peat, and are important carbon reservoirs. In areas with poor drainage, human-induced forest fires and logging can produce flooded conditions and organic matter accumulation, which generates an ecosystem called anthropogenic peatland. Productive management activities such as Sphagnum moss harvesting and livestock grazing take place there. Our hypothesis was that productive management has a strong impact on the aboveground C reservoir and increases the presence of exotic species. We established 44 sampling points in a 16-ha anthropogenic peatland on Chiloé Island, Chile, comparing productive and conservation types of managements. Carbon stocks, vegetation structure and composition variables were quantified. These variables were used to classify the ecosystem into microsites to analyze the different locations in the peatland. In addition, predictive models of aboveground carbon were created using Landsat 8 OLI and Pleiades images. The results revealed a carbon stock of 11.99 ± 0.77 kg C m−2, which is smaller than in natural peatlands, and showed a wide variability of conditions within the peatland itself. This variability, mainly expressed in aboveground carbon, produces microsites dominated by either shrubs, species of the genus Juncus or grasses. Productive management reduced accumulated carbon in the aboveground stock and in the woody debris. However, the strongest impact was found on the vegetation variables, with a decrease in total cover, cover of shrubs and herbaceous plants, and in vegetation height. There was also an increase in the richness and presence of exotic species. The spatial prediction of aboveground carbon yielded significant results using only spectral indices, showing also that the impact of productive management is not homogenous, being less intense in waterlogged areas. This study is the first to quantify carbon reservoirs in this type of ecosystem and to propose variables that can be used as indicators of the impact of human activities.art282126
Biogeoquímica2015Castro-González, M., & Farías, L.The influence of anoxia and substrate availability on N2O cycling by denitrification in the upper boundary of the oxygen minimum zone off northern ChileJournal of Marine Research10.1357/002224015817391285 accumulations of N2O at oxyclines are some of the most conspicuous features of the world’s oceans. However, the origin of these maxima, and the relative contribution of nitrification and denitrification in N2O cycling, remains unclear. In order to gain insight into the importance of denitrification and factors regulating N2O cycling at upper oxyclines in the eastern South Pacific, the production and consumption of N2O by denitrification were measured using a classical acetylene method under induced anoxia with the addition of an electron acceptor (nitrite) and donors (sodium acetate and glucose). The results indicated that decreased O2 clearly affected the ratio in which N2O is reduced to N2 at the midoxycline (∼40 m depth) and at the oxycline’s base (∼80 m depth). Under induced anoxia, higherN2Oproduction (fromNO− 2 toN2Oof 67.2 nM d−1) occurred at 40mdepth, with half of the total quantity being consumed by denitrification (from N2OtoN2 of 32 nM d−1); conversely,100%of theN2Owas reduced toN2 at 80mdepth. In comparison with previously reported results at the base of the oxycline at an offshore station, the addition ofNO− 2 (as sodium nitrite) along with dissolved organic carbon (as sodium acetate and glucose) doubled the net N2O production by denitrification (∼20 nM d−1). Our results suggest that decreasing O2 levels along with an increased availability of NO− 2 and organic compounds in the upper oxycline may impact the N2O/N2 ratio and, therefore, the N2O efflux to the atmosphere185–205673
Biogeoquímica2015Castro-González, M., Ulloa, O., & Farías, L.Structure of denitrifying communities reducing N2O at suboxic waters off northern Chile and PerúBiología Marina y Oceanografía10.4067/S0718-19572015000100008 nosZ gene, which encodes for N2 O reduction to N2 , was used to study the structure of denitrifying communities in the oxygen minimum zone off Chilean and Peruvian coast throughout terminal restriction fragment length polymorphism (TRFLP) and cloning of nosZ genes. TRFLP analysis showed little diversity of nosZ genes at suboxic depths (Oxygen Minimum Zone´s core) compared with depths where O2 largely varied (upper limit of OMZ or ULOMZ). The nosZ-denitrifying communities showed differences in its structure between geographical locations and time sampling suggesting an association with the shift in the environmental conditions. The canonical correspondence analysis showed that the environmental parameters selected as predictor variables (N2 O, O2 , NH4 + and NO2 -) explained well the differences in nosZ-denitrifying community composition among sampling sites. The phylogenetic analysis showed little nosZ sequence diversity and grouped 81% of nosZ-clones near the cluster of sediments sequences from Pacific. Our sequences did not branch with any known denitrifying bacteria or seawater nosZ-sequences available, demonstrating the novelty of phylotypes founded in this area.95–110150
Biogeoquímica2015Cornejo, M., Murillo, A. A., & Farías, L.An unaccounted for N2O sink in the surface water of the eastern subtropical South Pacific: Physical versus biological mechanismsProgress in Oceanography10.1016/j.pocean.2014.12.016 oxide (N2O) is a trace gas affecting atmospheric radiative forcing through its greenhouse effect in the troposphere and destroying the ozone in the stratosphere. The oceans account for one-third of the global atmospheric N2O emissions, in which they are primarily cycled by nitrification and denitrification, with high N2O production in the subsurface waters. The surface waters are generally reported to be in equilibrium or slightly supersaturated with respect to the atmosphere. However, surface N2O sub-saturations have been observed in several regions of the world's oceans, such as off south-central Chile, which is bathed by the Sub-Antarctic Water Mass (SAAW), where N2O subsaturations as low as 35% have been registered during the austral spring and summer. An analysis of the mechanisms driving such surface N2O subsaturations (physical or biological) showed that physical mechanisms were not responsible for the high surface N2O deficit. In contrast, in situ potential experiments in surface waters with 15N2O addition showed an active biological N2O fixation (between 0.43 and 87.34nmol/L/d), with the highest N2O fixation rates associated with the SAAW (25.25-25.75kg/m3).Additionally, incubation experiments with 15N2O in surface water samples from one oceanic station showed high 15N-POM enrichment (0.44‰) and an inhibition of 15N-POM enrichment when an additional nitrogen source was added (NO2 - and NH4 +). These results suggest the existence of a mechanism able to use several nitrogen sources, including N2O. Molecular analyses (16S rRNA gene) from these experiments showed the presence of three major groups of bacteria: Gammaproteobacteria, Flavobacteria and Cyanobacteria, with Synechococcus sp. being the dominant group in the culture. However, the analysis of the nifH gene showed a taxonomic affiliation to the order Stigonematales associated with Mastigocladus sp. and Fischerella sp. and the order Oscillatoriales associated with Trichodesmium sp.Finally, the oceanic region exhibiting surface N2O subsaturations acts as a sink for atmospheric N2O, consuming ∼11.4 Gg of N2O in a six-month period. The N2O levels in the sink are 75% higher than those of the reported N2O source from the coastal band. The balance between the oceanic region and the coastal band results in a sink region of 4.94 Gg of N2O during this period.12–23137
Dinámica del Clima2015Cuyckens, G. A. E., Christie, D. A., Domic, A. I., Malizia, L. R., & Renison, D.Climate change and the distribution and conservation of the world’s highest elevation woodlands in the South American AltiplanoGlobal and Planetary Change10.1016/j.gloplacha.2015.12.010 8115301600Climate change is becoming an increasing threat to biodiversity. Consequently, methods for delineation, establishment and management of protected areas must consider the species' future distribution in response to future climate conditions. Biodiversity in high altitude semiarid regions may be particularly threatened by future climate change. In this study we assess the main environmental variables that best explain present day presence of the world's highest elevation woodlands in the South American Altiplano, and model how climate change may affect the future distribution of this unique ecosystem under different climate change scenarios. These woodlands are dominated by Polylepis tarapacana (Rosaceae), a species that forms unique biological communities with important conservation value. Our results indicate that five environmental variables are responsible for 91% and 90.3% of the present and future P. tarapacana distribution models respectively, and suggest that at the end of the 21st century, there will be a significant reduction (56%) in the potential habitat for this species due to more arid conditions. Since it is predicted that P. tarapacana's potential distribution will be severely reduced in the future, we propose a new network of national protected areas across this species distribution range in order to insure the future conservation of this unique ecosystem. Based on an extensive literature review we identify research topics and recommendations for on-ground conservation and management of P. tarapacana woodlands.79–87137
Biogeoquímica2015Farías, L., Besoain, V., & García-Loyola, S.Dissolved greenhouse gases (nitrous oxide and methane) associated with the naturally iron-fertilized Kerguelen region (KEOPS 2 cruise) in the Southern OceanBiogeosciences10.5194/bg-12-1925-2015 concentrations of greenhouse gases (GHGs), such as nitrous oxide (N2O) and methane (CH4), were measured in the Kerguelen Plateau region (KPR). The KPR is affected by an annual microalgal bloom caused by natural iron fertilization, and this may stimulate the microbes involved in GHG cycling. This study was carried out during the KEOPS 2 cruise during the austral spring of 2011. Oceanographic variables, including N2O and CH4, were sampled (from the surface to 500 m depth) in two transects along and across the KRP, the north-south (TNS) transect (46°-51° S, ∼ 72° E) and the east-west (TEW) transect (66°-75° E, ∼ 48.3° S), both associated with the presence of a plateau, polar front (PF) and other mesoscale features. The TEW presented N2O levels ranging from equilibrium (105%) to slightly supersaturated (120%) with respect to the atmosphere, whereas CH4 levels fluctuated dramatically, being highly supersaturated (120-970%) in areas close to the coastal waters of the Kerguelen Islands and in the PF. The TNS showed a more homogenous distribution for both gases, with N2O and CH4 levels ranging from 88 to 171% and 45 to 666% saturation, respectively. Surface CH4 peaked at southeastern stations of the KPR (A3 stations), where a phytoplankton bloom was observed. Both gases responded significantly, but in contrasting ways (CH4 accumulation and N2O depletion), to the patchy distribution of chlorophyll a. This seems to be associated to the supply of iron from various sources. Air-sea fluxes for N2O (from -10.5 to 8.65, mean 1.25 ± 4.04 μmol m-2 d-1) and for CH4 (from 0.32 to 38.1, mean 10.01 ± 9.97 μmol-2 d-1) indicated that the KPR is both a sink and a source for N2O, as well as a considerable and variable source of CH4. This appears to be associated with biological factors, as well as the transport of water masses enriched with Fe and CH4 from the coastal area of the Kerguelen Islands. These previously unreported results for the Southern Ocean suggest an intense microbial CH4 production in the study area.1925–1940612
Biogeoquímica2015Farías, L., Florez-Leiva, L., Besoain, V., Sarthou, G., & Fernández, C.Presence of nitrous oxide hotspots in the coastal upwelling area off central Chile: an analysis of temporal variability based on ten years of a biogeochemical time seriesEnvironmental Research Letters10.1088/1748-9326/10/4/044017 and inter-annual variabilities of biogeochemical variables, including nitrous oxide (N2O), an important climate active gas, were analyzed during monthly observations between 2002 and 2012 at an ocean Time-Series station in the coastal upwelling area off central Chile (36° 30.8′; 73° 15′). Oxygen, N2O, nutrients and chlorophyll-a (Chl-a) showed clear seasonal variability associated with upwelling favorable winds (spring–summer) and also inter-annual variability, which in the case of N2O was clearly observed during the occurrence of N2O hotspots with saturation levels of up to 4849%. These hotspots consistently took place during the upwelling-favorable periods in 2004, 2006, 2008, 2010 and 2011, below the mixed layer (15–50 m depth) in waters with hypoxia and some accumulation. The N2O hotspots displayed excesses of N2O (ΔN2O) three times higher than the average monthly anomalies (2002–2012). Estimated relationships of ΔN2O versus apparent oxygen utilization (AOU), and ΔN2O versus suggest that aerobic ammonium oxidation (AAO) and partial denitrification are the processes responsible for high N2O accumulation in subsurface water. Chl-a levels were reasonably correlated with the presence of the N2O hotspots, suggesting that microbial activities fuelled by high availability of organic matters lead to high N2O production. As a result, this causes a substantial N2O efflux into the atmosphere of up to 260 μmol m−2 d−1. The N2O hotspots are transient events or hot moments, which may occur more frequently than they are observed. If so, this upwelling area is producing and emitting greater than expected amounts of N2O and is therefore an important N2O source that should be considered in the global atmospheric N2O balance.44017410
Biogeoquímica2015Fernandez, C., González, M. L., Muñoz, C., Molina, V., & Farías, L.Temporal and spatial variability of biological nitrogen fixation off the upwelling system of central Chile (35-38.5°S)Journal of Geophysical Research: Oceans10.1002/2014JC010410 N2 fixation could represent a supplementary source of bioavailable nitrogen in coastal upwelling areas and underlying oxygen minimum zones (OMZs), the limited data available prevent assessing its variability and biogeochemical significance. Here we report the most extensive N2 fixation data set gathered to date in the upwelling area off central Chile (36°S). It covers interannual to high frequency time scales in an area of about 82,500 km2 in the eastern South Pacific (ESP). Because heterotrophic N2 fixation may be regulated by DOM availability in the ESP, we conducted experiments at different oxygen conditions and included DOM amendments in order to test diazotrophic activity. Rates in the euphotic zone showed strong temporal variability which resulted in values reaching 0.5 nmol L-1 d-1 in 2006 (average 0.32 ± 0.17 nmol L-1 d-1) and up to 126.8 nmol L-1 d-1 (average 24.75 ± 37.9 nmol L-1 d-1) in 2011. N2 fixation in subsurface suboxic conditions (1.5 ± 1.16 nmol L-1 d-1) also occurred mainly during late summer and autumn while virtually absent in winter. The diversity of diazotrophs was dominated by heterotrophs, with higher richness in surface compared to OMZ waters. Rates in oxygen depleted conditions could exceed values obtained in the euphotic layer, but rates were not dependent on the availability of dissolved organic matter. N2 fixation also showed a positive correlation with total chlorophyll and the C:N ratio of phytoplankton, but not to the P excess compared to N. We conclude that the diazotrophic community responds to the composition of phytoplankton rather than the extent of N deficiency and the availability of bulk DOM in this system. Key Points: The largest N2 fixation data set for the Eastern South Pacific is presented N2 fixation activity decreases from coast to open ocean N2 fixation is likely to be dominated by heterotrophic bacterioplankton3330–33495120
Biogeoquímica2015Fink, H. G., Wienberg, C., de Pol-Holz, R., & Hebbeln, D.Spatio-temporal distribution patterns of Mediterranean cold-water corals (Lophelia pertusa and Madrepora oculata) during the past 14,000 yearsDeep Sea Research Part I: Oceanographic Research Papers10.1016/j.dsr.2015.05.006 study presents newly obtained coral ages of the cold-water corals Lophelia pertusa and Madrepora oculata collected in the Alboran Sea and the Strait of Sicily (Urania Bank). These data were combined with all available Mediterranean Lophelia and Madrepora ages compiled from literature to conduct a basin-wide assessment of the spatial and temporal occurrence of these prominent framework-forming scleractinian species in the Mediterranean realm and to unravel the palaeo-environmental conditions that controlled their proliferation or decline. For the first time special focus was placed on a closer examination of potential differences occurring between the eastern and western Mediterranean sub-basins. Our results clearly demonstrate that cold-water corals occurred sparsely in the entire Mediterranean during the last glacial before becoming abundant during the Bølling-Allerød warm interval, pointing to a basin-wide, almost concurrent onset in (re-)colonisation after ∼13.5. ka. This time coincides with a peak in meltwater discharge originating from the northern Mediterranean borderlands which caused a major reorganisation of the Mediterranean thermohaline circulation. During the Younger Dryas and Holocene, some striking differences in coral proliferation were identified between the sub-basins such as periods of highly prolific coral growth in the eastern Mediterranean Sea during the Younger Dryas and in the western basin during the Early Holocene, whereas a temporary pronounced coral decline during the Younger Dryas was exclusively affecting coral sites in the Alboran Sea. Comparison with environmental and oceanographic data revealed that the proliferation of the Mediterranean corals is linked with enhanced productivity conditions. Moreover, corals thrived in intermediate depths and showed a close relationship with intermediate water mass circulation in the Mediterranean sub-basins. For instance, reduced Levantine Intermediate Water formation hampered coral growth in the eastern Mediterranean Sea during sapropel S1 event as reduced Winter Intermediate Water formation did in the westernmost part of the Mediterranean (Alboran Sea) during the Mid-Holocene. Overall, this study clearly demonstrates the importance to consider region-specific environmental changes as well as species-specific environmental preferences in interpreting coral chronologies. Moreover, it highlights that the occurrence or decline of cold-water corals is not controlled by one key parameter but rather by a complex interplay of various environmental variables.37–48103
Dinámica del Clima2015García-Plazaola, J. I., Rojas, R., Christie, D. A., & Coopman, R. E.Photosynthetic responses of trees in high-elevation forests: Comparing evergreen species along an elevation gradient in the Central Andes.AoB plants10.1093/aobpla/plv058 growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation, and water scarcity. These conditions are particularly harsh in the tropics, where the highest elevation treelines occur. In this environment the maintenance of a positive carbon balance involves protecting the photosynthetic apparatus and taking advantage of any climatically favorable periods. To characterize photoprotective mechanisms at such high elevations, and particularly to address the question of whether these mechanisms are the same as those previously described in woody plants along extratropical treelines, we have studied photosynthetic responses in Polylepis tarapacana in the central Andes (18 °S) along an elevational gradient from 4,300 to 4,900 m. For comparative purposes this gradient has been complemented with a lower elevation site (3,700 m) where another Polylepis species (P. rugulosa) occurs. During the daily cycle, two periods of photosynthetic activity were observed: one during the morning when, despite low temperatures, assimilation was high; and the second starting at noon when the stomata closed because of a rise in the vapor pressure deficit and thermal dissipation is prevalent over photosynthesis. From dawn to noon there was a decrease in the content of antenna pigments (chlorophyll b and neoxanthin), together with an increase in the content of xanthophyll cycle carotenoids. These results could be caused by a reduction in the antenna size along with an increase in photo-protection. Additionally, photo-protection was enhanced by a partial overnight retention of de-epoxised xanthophylls. The unique combination of all of these mechanisms made possible the efficient use of the favorable conditions during the morning while still providing enough protection for the rest of the day. This strategy differs completely from that of extratropical mountain trees, which uncouple light-harvesting and energy-use during long periods of unfavorable, winter conditions.plv05807
Biogeoquímica2015Gayo, E. M., Latorre, C., & Santoro, C. M.Timing of occupation and regional settlement patterns revealed by time-series analyses of an archaeological radiocarbon database for the South-Central Andes (16°–25°S)Quaternary International10.1016/j.quaint.2014.09.076 spatially resolved high-resolution datasets of robust long-term changes in human demography constitutes a major challenge for archaeology. One approach is to use the distribution of summed radiocarbon-age probabilities to infer long-term population dynamics (i.e. palaeodemography). However, these can often be biased by preservation potential, site taphonomy or researcher priorities among other aspects, all of which require large datasets to resolve adequately. For this report, we have created such a dataset for the South-Central Andes (16°-25°S), here termed the South Central Andes Radiocarbon (SCAR) database. SCAR spans the last 15,000 years and incorporates ∼1700 14C-dates from 519 archeological sites reported across an extreme bioclimatic gradient that includes the hyperarid coastal Atacama Desert and adjacent cold, high-elevation Altiplano. Among the possible methodological biases, we first evaluated those related to calibration procedures. Otherwise, changes in summed probability curves show no other relevant biases except for possible research interest/priorities that could be responsible for the gaps in the record from the Bolivian altiplano. Our temporally continuous time-series indicates that prehispanic populations exhibited significant demographic changes during the last 13,100calBP. Except for coastal populations; most regions show strongly coordinated demographic fluctuations that follow the same major patterns. Thus, we identified two broad scale population events across the South-Central Andes (Atacama inland, Bolivian Altiplano) from 13,100-4000calBP and then from 4000calBP to the present. In contrast, the Atacama coastal records suggest a different and more variable occupation pattern over the last 13,460calBP, which could be driven by the interaction with oceanographic processes (i.e. upwelling). A widespread major decline at 700calBP clearly predates the Spanish colonization and occurs in all of our regions. This widespread decline does not appear to be due to methodological biases, and suggests that a population crash occurred before European occupation. Overall, the SCAR database constitutes a valuable proxy for establishing the long-term dynamics of prehistoric societies that inhabited the western Andean slope. Time-series analyses that use SCAR will shed new light on the demographic and cultural dynamics at different spatial-scales, and help clarify the processes involved in the migrational trajectories and cultural evolution of the peoples that inhabited the South-Central Andes over the last 15,000 years.4–14356
Servicios Ecosistémicos2015González, M. E., Donoso, P. J., & Szejner, P.Tree-fall gaps and patterns of tree recruitment and growth in Andean old-growth forests in south-central ChileBosque10.4067/S0717-92002015000300006 gaps have been recognized as an important process in the regeneration dynamics of Andean old-growth forests (ca. 40º S). The objectives of the study were to determine main tree-fall gap attributes and to assess tree recruitment and growth patterns in tree-fall gaps of two mid-elevation Andean old-growth forests. We measured the canopy and expanded area of each gap, and for the gap-maker species we measured its diameter at breast height (dbh), felling direction and type of treefall. In each gap, tree seedlings, saplings and bamboo culms were counted in subplots. Increment cores of potential successors were obtained to examine growth patterns. There was a larger area in canopy gaps in NF than in STF (25.8 vs. 11.9 %). Expanded gaps were on average larger in NF than in STF (547 vs. 440 m2 ). Most gaps were originated by wind-snap and upturned root-plates of all the major tree species (Laureliopsis philippiana, Saxegothaea conspicua and Dasyphyllum diacanthoides, and Nothofagus dombeyi in NF). The understory species Chusquea culeou was an important competitor in gaps, especially in STF where the bamboo was more effective inhibiting the recruitment of tree seedlings. The successful recruitment of shade-tolerant tree species beneath endogenous tree-fall gaps indicates that these species follow a gap-phase regeneration mode through which –after several growth releases- they can reach the main canopy. These studies could offer valuable insights for the urgently required restoration and management of Andean old-growth forests.383–394336
Servicios Ecosistémicos2015González, M. E., & Lara, A.Large fires in the Andean Araucaria forests: when a natural ecological process becomes a threatOryx10.1017/S0030605315000599 fire season of 2014–2015 in Chile has been one of the worst of the last 50 years, with large and simultaneous fires affecting vast areas of Andean Araucaria–Nothofagus forests in several national parks, forest reserves and private properties. The worst-affected protected areas are China Muerta and Malleco National Reserves, and Conguillío and Tolhuaca National Parks, with an estimated total area of.12,000 ha burned. In 2002 fires burned.20,000 ha, af- fecting mostly the same protected areas and other private land covered by Araucaria forests, with c. 30 and 60%of the total area of Malleco National Reserve and Tolhuaca National Park burned, respectively. As then, the 2014–2015 fires have stirred public, political and scientific concern.394349
Servicios Ecosistémicos2015González, M. E., Szejner, P., Donoso, P. J., & Salas, C.Fire, logging and establishment patterns of second-growth forests in south-central Chile: implications for their management and restorationCiencia e investigación agraria10.4067/S0718-16202015000300011 forests represent the greatest potential resource for forest management and large-scale ecological restoration in many regions. In south-central Chile, second-growth forests include those dominated by Nothofagus obliqua , N. dombeyi , Drimys winteri , and a mixture of evergreen species, especially hardwoods. This article examines the influence of fire and logging on the establishment patterns and development of second-growth forests in south-central Chile. We characterize the size structure and composition of these four types of forests with sampling plots. The identification of the type of disturbance and its date of occurrence was determined from evidence such as fire scars and even-aged pulses of tree establishment. The size, structure and species composition of these forests indicate an intermediate state of development with an average density and basal area ranging from 1294 to 5038 trees ha -1 and from 59 to 85 m 2 ha -1 , respectively. Logging and/or devastating fires that occurred in the early decades of the 1900s promoted the relatively rapid establishment and growth of pioneer species ( Nothofagus obliqua, N. dombeyi, D. winteri ). In the Mixed Evergreen second-growth forests, mid-shade or shade tolerant species (e.g., Gevuina avellana, Eucryphia cordifolia, Amomyrtus luma, and A. meli ) became established mostly through vegetative sprouting. Fires and logging have been pervasive factors in determining the structural and compositional uniformity of the native forests of south-central Chile. Ecological restoration at a landscape level, either by ecological processes (i.e., a reduction in fire frequency) and/or the structure and composition of second-growth forests, provide a relevant approach to accelerating the generation of attributes of old-growth forests, therefore meeting manifold societal demands for forest goods and services. Los bosques secundarios representan el mayor recurso forestal para el manejo y la restauración de gran escala en muchas regiones del mundo. En el centro-sur de Chile los bosques secundarios están dominados por Nothofagus obliqua , N. dombeyi , D. winteri , y Siempreverde mixtos. El presente artículo examina la influencia del fuego y tala en los patrones de establecimiento y desarrollo de bosques secundarios de la región centro-sur de Chile. Para la caracterización de la estructura y composición de cada bosque secundario se seleccionaron rodales representativos estableciendo 4-6 parcelas de 900 m 2 . El tipo de disturbio y su fecha de ocurrencia fue establecido a través de evidencias tales como cicatrices de fuego y pulsos de establecimiento de árboles. La estructura de tamaños y composición indican un estado de desarrollo intermedio o de reiniciación del sotobosque presentando en promedio una densidad y área basal que varía entre 1294 y 5038 árboles ha -1 y entre 59 y 85 m 2 ha -1 , respectivamente. Incendios de gran severidad y/o madereo ocurridos en las primeras décadas de los 1900 promovieron un rápido establecimiento de las principales especies pioneras ( Nothofagus obliqua, N. dombeyi, D. winteri ). En los bosques secundarios Siempreverde mixtos, el establecimiento de especies tolerantes o semi-tolerantes a la sombra (ej., Gevuina avellana, Eucryphia cordifolia ), fue principalmente por rebrotes vegetativos. El fuego y madereo han sido agentes clave en determinar la uniformidad estructural y composicional de los bosques nativos del centro-sur de Chile. La restauración ecológica a escala de paisaje, tanto de procesos ecológicos (frecuencia incendios) como de la estructura y composición de los bosques secundarios, ofrece una relevante aproximación para acelerar la generación de atributos de bosques antiguos que satisfagan los múltiples bienes y servicios ecosistémicos demandados por la sociedad.11–11342
Modelación y Sistemas de Observación2015Henriquez, A., Osses, A., Gallardo, L., & Diaz Resquin, M.Analysis and optimal design of air quality monitoring networks using a variational approachTellus B10.3402/tellusb.v67.25385 quality networks need revision and optimisation as instruments and network requirements, both scientific and societal, evolve over time. Assessing and optimising the information content of a monitoring network is a non-trivial problem. Here, we introduce a methodology formulated in a variational framework using an air quality model to simulate the dispersion of carbon monoxide (CO) as a passive tracer at the city scale.Weaddress the specific case of adding or removing stations, and the more general situation of optimally distributing a given number of stations in a domain taking into account transport patterns and spatial factors such as population density and emission patterns.Weconsider three quality indicators: precision gain, information gain and degrees of freedom for a signal. These metrics are all functions of the singular values of the sensitivity matrix that links emissions and observations in the variational framework.Weillustrate the application of the methodology in the case of Santiago (33.58S, 70.58W, 500ma.s.l.), a city of ca. 7 million inhabitants with significant pollution levels. Wedeem information gain as the best of the above indicators for this case.Wethen quantify the actual evolution of Santiago’s network and compare it with the optimal configuration suggested by our methodology and with results previously obtained using a statistical approach. The application is restricted to diurnal and summer conditions, for which the dispersion model shows a good agreement with observations. The current method offers advantages in that it allows extending a network to include new sites, and it explicitly considers the effects of dispersion patterns, and desired weighting functions such as emission fluxes and population density. We find that Santiago’s air quality has improved two-fold since 1988, regarding CO under diurnal summer conditions. Still, according to our results, the current configuration could be improved by integrating more suburban stations in the southwest of the basin.1–13067
Dinámica del Clima2015Henríquez, W. I., Moreno, P. I., Alloway, B. V., & Villarosa, G.Vegetation and climate change, fire-regime shifts and volcanic disturbance in Chiloé Continental (43°S) during the last 10,000 yearsQuaternary Science Reviews10.1016/j.quascirev.2015.06.017 the roles of paleofires and explosive volcanism from climatic drivers of past vegetation change is a subject insufficiently addressed in the paleoecological literature. The coastal region of the Chiloé Continental sector of northwestern Patagonia is ideal in this regard considering its proximity to active eruptive centers and the possibility of establishing comparisons with more distal, upwind sites where volcanic influence is minimal. Here we present a fine-resolution pollen and macroscopic charcoal record from Lago Teo with the aim of documenting the local vegetation and climate history, and assessing the role of disturbance regimes as drivers of vegetation change during the last ∼10,000 years. The Lago Teo record shows a conspicuous warm/dry interval between ∼7500 and 10,000 cal yrs BP followed by a cooling trend and increase in precipitation that has persisted until the present, in agreement with previous studies in the region and interpretations of past southern westerly wind activity at multi-millennial scales. The presence of 26 tephras throughout the record allows examination of the relationship between explosive volcanism and vegetation change under contrasting climatic states of the Holocene. We found consistent statistically significant increases in Tepualia stipularis after tephra deposition over the last 10,000 years, in Eucryphia/Caldcluvia between 7500 and 10,000 cal yrs BP and in Hydrangea over the last 7500 years. Our results indicate a primary role of climate change as driver of long-term vegetation change and as a modulator of vegetation responses to volcanic disturbance at multidecadal and centennial timescales.158–167123
Dinámica del Clima2015Jacques-Coper, M., & Garreaud, R.Characterization of the 1970s climate shift in South AmericaInternational Journal of Climatology10.1002/joc.4120 1976-1977 cold-to-warm sea surface temperature (SST) shift in the tropical Pacific Ocean, which has been associated with a phase change of the Pacific Decadal Oscillation (PDO) index, separated a 'La Niña-like' decadal regime from an 'El Niño-like' one. In this article, we analyse the differences of mean of annual and austral-summer (DJF) temperature, precipitation, and sea-level pressure (SLP) over South America (SA) between 1961-1973 and 1978-1990, and explore the occurrence of significant shifts in their time series. Our sources are instrumental records, gridded interpolated data, and reanalyses. Although major regional differences in the intensity of the signal are detected, the climate shift is identified in all variables. In the mid-1970s at annual level, reanalysis SLP data reveal the onset of a step-like anticyclonic circulation anomaly in the southern tip of SA and an abrupt weakening of the Southeast Pacific Subtropical Anticyclone (SEPA). This latter feature may have partly induced the rapid warming observed along the tropical-extratropical west coast of the continent through the weakening of the cold Humboldt current system. An abrupt warming was also detected in surface air temperature (SAT) composites located along the coast of the northern part of SA and in Southeastern SA (SESA). During summer, we found a particularly conspicuous shift-like warming over Southern South America (SSA, comprising Patagonia). Besides, a shift-like increase (decrease) in annual mean precipitation is observed over Central Argentina and in the tropics, to the south (north) of 10°S. In line with previous studies, we conclude that both the interannual (El Niño-Southern Oscillation, ENSO) and the interdecadal (PDO) variability modes seem to have had an incidence in the manifestation of the 1970s climate shift, and that its magnitude appears to be unprecedented during the 20th century, as shown in particular by century-long SAT composites from northern Chile and SSA.2164–2179835
Biogeoquímica; Modelación y Sistemas de Observación2015Lambert, F., Tagliabue, A., Shaffer, G., Lamy, F., Winckler, G., Farías, L., … de Pol-Holz, R.Dust fluxes and iron fertilization in Holocene and Last Glacial Maximum climatesGeophysical Research Letters10.1002/2015GL064250 dust aerosols play a major role in present and past climates. To date, we rely on climate models for estimates of dust fluxes to calculate the impact of airborne micronutrients on biogeochemical cycles. Here we provide a new global dust flux data set for Holocene and Last Glacial Maximum (LGM) conditions based on observational data. A comparison with dust flux simulations highlights regional differences between observations and models. By forcing a biogeochemical model with our new data set and using this model's results to guide a millennial-scale Earth System Model simulation, we calculate the impact of enhanced glacial oceanic iron deposition on the LGM-Holocene carbon cycle. On centennial timescales, the higher LGM dust deposition results in a weak reduction of <10ppm in atmospheric CO2 due to enhanced efficiency of the biological pump. This is followed by a further ∼10ppm reduction over millennial timescales due to greater carbon burial and carbonate compensation.6014–60231442
Modelación y Sistemas de Observación2015Landais, A., Masson-Delmotte, V., Stenni, B., Selmo, E., Roche, D. M., Jouzel, J., Lambert, F., … Popp, T.A review of the bipolar see–saw from synchronized and high resolution ice core water stable isotope records from Greenland and East AntarcticaQuaternary Science Reviews10.1016/j.quascirev.2015.01.031 ice core records are now available that cover the Last Glacial cycle both in Greenland and in Antarctica. Recent developments in coherent ice core chronologies now enable us to depict with a precision of a few centuries the relationship between climate records in Greenland and Antarctica over the millennial scale variability of the Last Glacial period. Stacks of Greenland and Antarctic water isotopic records nicely illustrate a seesaw pattern with the abrupt warming in Greenland being concomitant with the beginning of the cooling in Antarctica at the Antarctic Isotopic Maximum (AIM). In addition, from the precise estimate of chronological error bars and additional high resolution measurements performed on the EDC and TALDICE ice cores, we show that the seesaw pattern does not explain the regional variability in Antarctic records with clear two step structures occurring during the warming phase of AIM 8 and 12. Our Antarctic high resolution data also suggest possible teleconnections between changes in low latitude atmospheric circulation and Antarctic without any Greenland temperature fingerprint.18–32114
Servicios Ecosistémicos2015Lara, A., Bahamondez, A., González-Reyes, A., Muñoz, A. A., Cuq, E., & Ruiz-Gómez, C.Reconstructing streamflow variation of the Baker River from tree-rings in Northern Patagonia since 1765Journal of Hydrology10.1016/j.jhydrol.2014.12.007 understanding of the long-term variation of large rivers streamflow with a high economic and social relevance is necessary in order to improve the planning and management of water resources in different regions of the world. The Baker River has the highest mean discharge of those draining both slopes of the Andes South of 20°S and it is among the six rivers with the highest mean streamflow in the Pacific domain of South America (1100m3s-1 at its outlet). It drains an international basin of 29,000km2 shared by Chile and Argentina and has a high ecologic and economic value including conservation, tourism, recreational fishing, and projected hydropower. This study reconstructs the austral summer - early fall (January-April) streamflow for the Baker River from Nothofagus pumilio tree-rings for the period 1765-2004. Summer streamflow represents 45.2% of the annual discharge. The regression model for the period (1961-2004) explains 54% of the variance of the Baker River streamflow (R2adj=0.54). The most significant temporal pattern in the record is the sustained decline since the 1980s (τ=-0.633, p=1.0144*10-5 for the 1985-2004 period), which is unprecedented since 1765. The Correlation of the Baker streamflow with the November-April observed Southern Annular Mode (SAM) is significant (1961-2004, r=-0.55, p511–523P2529
Servicios Ecosistémicos2015Little, C., Cuevas, J. G., Lara, A., Pino, M., & Schoenholtz, S.Buffer effects of streamside native forests on water provision in watersheds dominated by exotic forest plantationsEcohydrology10.1002/eco.1575 Valdivian rainforest ecoregion in Chile (35°-48°S) has a high conservation priority worldwide. These forests are also keys for social welfare as a result of their supply of timber as well as ecosystem services. Forests in the ecoregion have been extensively converted to fast growing Pinus radiata and Eucalyptus spp. plantations for timber production promoted by public policies and timber companies. This study describes the results of detailed measurements of hydrology and stream water chemistry in eight small watersheds in south central Chile, subjected to replacement of native temperate rainforest by exotic Eucalyptus plantations. In this system, watersheds have streamside buffers of native forest (SNFW) with varying widths. Results indicate that retention of SNFW counteracts hydrologic effects of Eucalyptus plantations, which are widely known to reduce water yields. A 1.4% rate of increase of the run-off coefficient for each metre of increase of SNFW was observed. In addition, a decrease in the concentrations of total nitrogen, dissolved inorganic nitrogen (DIN), nitrate-N, and different sized fractions of particulate organic matter were found in streams draining these plantations as a function of increasing SNFW. Streamside buffer widths of 17-22m for total nitrogen and DIN concentrations and ≥36m for sediments were required to provide comparable values to reference watersheds (100% native forest). The findings from this study suggest that SNFW may significantly reduce adverse effects from exotic species forestry plantations on water provision in an area of south central Chile where exotic forest plantations are rapidly expanding. © 2015 John Wiley1205–121778
Biogeoquímica2015Masotti, I., Belviso, S., Bopp, L., Tagliabue, A., & Bucciarelli, E.Effects of light and phosphorus on summer DMS dynamics in subtropical waters using a global ocean biogeochemical modelEnvironmental Chemistry10.1071/EN14265 occurrence of a summer DMS paradox in the vast subtropical gyres is a strong matter of debate because approaches using discrete measurements, climatological data and model simulations yielded contradictory results. The major conclusion of the first appraisal of prognostic ocean DMS models was that such models need to give more weight to the direct effect of environmental forcings (e.g. irradiance) on DMS dynamics to decouple them from ecological processes. Here, the relative role of light and phosphorus on summer DMS dynamics in subtropical waters is assessed using the ocean general circulation and biogeochemistry model NEMO-PISCES in which macronutrient concentrations were restored to monthly climatological data values to improve the representation of phosphate concentrations. Results show that the vertical and temporal decoupling between chlorophyll and DMS concentrations observed in the Sargasso Sea during the summer months is captured by the model. Additional sensitivity tests show that the simulated control of phosphorus on surface DMS concentrations in the Sargasso Sea is much more important than that of light. By extending the analysis to the whole North Atlantic Ocean, we show that the longitudinal distribution of DMS during summer is asymmetrical and that a correlation between the solar radiation dose and DMS concentrations only occurs in the Sargasso Sea. The lack of a widespread summer DMS paradox in our model simulation as well as in the comparison of discrete and climatological data could be due to the limited occurrence of phosphorus limitation in the global ocean.
Servicios Ecosistémicos2015Miranda, A., Altamirano, A., Cayuela, L., Pincheira, F., & Lara, A.Different times, same story: Native forest loss and landscape homogenization in three physiographical areas of south-central of ChileApplied Geography10.1016/j.apgeog.2015.02.016 forest represents the smallest area among the main world's forest biomes, but is one of those most threatened by forest loss. Chile contains most of the temperate forest in South America and more than half of the temperate forest in the southern hemisphere. Chilean temperate forest is considered to be one of the world's biodiversity hotspots. In this study we assessed the rate of land use and land cover (LULC) change over time, identified the main LULCs replacing native forest, and described how changes have evolved in contrasting physiographical conditions and through different historical phases of the landscape over the last 40 years. To achieve this, we analysed LULC change with particular focus on forest cover in three areas representing different physiographical conditions and histories of human occupation in the Araucanía Region of Chile, namely the Central Valley, the Coastal range, and the Andean range. We found substantial differences in temporal and intra-regional patterns of forest loss and LULC change. In the Central Valley, forest loss started long ago, and the area occupied by native forest nowadays is less than 5% of the landscape. In the Coastal range, rapid land cover change has taken place since 1973, with an increasing rate of forest loss over time. We detected a similar but less intense pattern in the forests of the Andean range. Overall, the general pattern points to a process of landscape homogenization in all three physiographical areas. Exotic tree plantations have spread over large geographical areas, becoming the dominant land cover. Land cover change in the Araucanía Region reflects a model of change in which areas with better environmental conditions and accessibility are occupied first for productive activities. As the availability of suitable areas for the expansion of productive activities diminishes, these activities start to move into physiographical areas which were previously “protected” by adverse environmental conditions or poor accessibility. This model of production growth could lead to the complete deforestation of areas outside national protected areas, and other areas which still remain inaccessible due to technological restrictions on exploitation.20–2860
Dimensión Humana; Dinámica del Clima; Modelación y Sistemas de Observación2015Molina, L. T., Gallardo, L., Andrade, M., Baumgardner, D., Borbor- Córdova, M., Bórquez, R., Garreaud, R. D., Huneeus, N., Lambert, F., … Schwarz, J. P.Pollution and its impacts on the South American Cryosphere (PISAC)Earth's Future10.1002/2015EF000311 article is a review of the science goals and activities initiatedwithin the framework of the Pollution and its Impacts on the South American Cryosphere (PISAC) initiative. Air pollution associated with biomass burning and urban emissions affects extensive areas of South America.We focus on black carbon (BC) aerosol and its impacts on air quality, water availability, and climate, with an emphasis on the Andean cryosphere. BC is one of the key short-lived climate pollutants that is a topic of growing interest for near-termmitigation of these issues. Limited scientific evidence indicates that the Andean cryosphere has already responded to climate change with receding glaciers and snow cover, which directly affect water resources, agriculture, and energy production in the Andean region of South America. Despite the paucity of systematic observations along the Andes, a few studies have detected BC on snow and glaciers in the Andes. These, in addition to existing and projected emissions and weather patterns, suggest a pos- sible contribution of BC to the observed retreat of the Andean cryosphere. Here we provide an overview of the current understanding of these issues from scientific and policy perspectives, and propose strategic expansionsn/a–n/a123
Dinámica del Clima2015Moreno, P. I., Denton, G. H., Moreno, H., Lowell, T. V., Putnam, A. E., & Kaplan, M. R.Radiocarbon chronology of the last glacial maximum and its termination in northwestern PatagoniaQuaternary Science Reviews10.1016/j.quascirev.2015.05.027 examine the timing and magnitude of the last glacial maximum (LGM) and the last glacial termination (LGT) in northwestern Patagonia, situated in the middle latitudes of South America. Our data indicate that the main phase of the LGT began with abrupt warm pulses at 17,800 and 17,100calyrs BP, accompanied by rapid establishment of evergreen temperate rainforests and extensive deglaciation of the Andes within 1000 years. This response shows that South American middle-latitude temperatures had approached average interglacial values by 16,800calyrs BP. The temperature rise in northwestern Patagonia coincides with the beginning of major warming and glacier recession in the Southern Alps of New Zealand at southern mid-latitudes on the opposite side of the Pacific Ocean. From this correspondence, the warming that began at 17,800calyrs BP appears to have been widespread in middle latitudes of the Southern Hemisphere, accounting for at least 75% of the total temperature recovery from the LGM to the Holocene. Moreover, this warming pulse is coeval with the first half of the Heinrich Stadial 1 (HS1) in the North Atlantic region. HS1 featured a decline of North Atlantic meridional overturning circulation, a southward shift of the westerly wind belt in both hemispheres and of the Intertropical Convergence Zone, as well as a weakening of the Asian monsoon. Along with the initiating trigger, identifying the mechanisms whereby these opposing climate signals in the two polar hemispheres interacted -whether through an oceanic or an atmospheric bipolar seesaw, or both- lies at the heart of understanding the LGT.233–249122
Dinámica del Clima2015Neukom, R., Rohrer, M., Calanca, P., Salzmann, N., Huggel, C., Acuña, D., Christie, D. A., … Morales, M. S.Facing unprecedented drying of the Central Andes? Precipitation variability over the period AD 1000–2100Environmental Research Letters10.1088/1748-9326/10/8/084017 future trends in water availability are associated with large uncertainties in many regions of the globe. In mountain areas with complex topography, climate models have often limited capabilities to adequately simulate the precipitation variability on small spatial scales. Also, their validation is hampered by typically very low station density. In the Central Andes of South America, a semi-arid high-mountain region with strong seasonality, zonal wind in the upper troposphere is a good proxy for interannual precipitation variability. Here, we combine instrumental measurements, reanalysis and paleoclimate data, and a 57-member ensemble of CMIP5 model simulations to assess changes in Central Andes precipitation over the period AD 1000–2100. This new database allows us to put future projections of precipitation into a previously missing multi-centennial and pre-industrial context. Our results confirm the relationship between regional summer precipitation and 200 hPa zonal wind in the Central Andes, with stronger Westerly winds leading to decreased precipitation. The period of instrumental coverage (1965–2010) is slightly dryer compared to pre-industrial times as represented by control simulations, simulations from the past Millennium, ice core data from Quelccaya ice cap and a tree-ring based precipitation reconstruction. The model ensemble identifies a clear reduction in precipitation already in the early 21st century: the 10 year running mean model uncertainty range (ensemble 16–84% spread) is continuously above the pre-industrial mean after AD 2023 (AD 2028) until the end of the 21st century in the RCP2.6 (RCP8.5) emission scenario. Average precipitation over AD 2071–2100 is outside the range of natural pre-industrial variability in 47 of the 57 model simulations for both emission scenarios. The ensemble median fraction of dry years (defined by the 5th percentile in pre-industrial conditions) is projected to increase by a factor of 4 until 2071–2100 in the RCP8.5 scenario. Even under the strong reduction of greenhouse gas emissions projected by the RCP2.6 scenario, the Central Andes will experience a reduction in precipitation outside pre-industrial natural variability. This is of concern for the Central Andes, because society and economy are highly vulnerable to changes in the hydrological cycle and already have to face decreases in fresh water availability caused by glacier retreat.84017810
Dinámica del Clima2015Pino, P., Iglesias, V., Garreaud, R., Cortés, S., Canals, M., Folch, W., … Steenland, K.Chile Confronts its Environmental Health Future After 25 Years of Accelerated GrowthAnnals of Global Health10.1016/j.aogh.2015.06.008 Chile has recently been reclassified by the World Bank from an upper-middle-income country to a high-income country. There has been great progress in the last 20 to 30 years in relation to air and water pollution in Chile. Yet after 25 years of unrestrained growth, there remain clear challenges posed by air and water pollution, as well as climate change. OBJECTIVE: The aim of this study was to review environmental health in Chile. METHODS: In late 2013, a 3-day workshop on environmental health was held in Santiago, Chile, bringing together researchers and government policymakers. As a follow-up to that workshop, here we review the progress made in environmental health in the past 20 to 30 years and discuss the challenges of the future. We focus on air and water pollution and climate change, which we believe are among the most important areas of environmental health in Chile. RESULTS: Air pollution in some cities remains among the highest in the continent. Potable water is generally available, but weak state supervision has led to serious outbreaks of infectious disease and ongoing issues with arsenic exposure in some regions. Climate change modeling in Chile is quite sophisticated, and a number of the impacts of climate change can be reasonably predicted in terms of which areas of the country are most likely to be affected by increased temperature and decreased availability of water, as well as expansion of vector territory. Some health effects, including changes in vector-borne diseases and excess heat mortality, can be predicted. However, there has yet to be an integration of such research with government planning. CONCLUSIONS: Although great progress has been made, currently there are a number of problems. We suspect that the Chilean experience in environmental health may be of some use for other Latin American countries with rapid economic development.354–367381
Biogeoquímica2015Rondanelli, R., Molina, A., & Falvey, M.The Atacama Surface Solar MaximumBulletin of the American Meteorological Society10.1175/BAMS-D-13-00175.1 have presented a descriptive analysis showing a suite of different global products that combine information from models and satellites to provide the global distribution of surface total solar radiation as well as the distribution of the main substances that explain the atmospheric extinction of solar radiation reaching the surface. Latitude, elevation, cloud fraction, water vapor, and aerosols have a first-order influence on the distribution of surface solar radiation over the planet, and no single factor explains the combined distribution. The most likely location of the total solar radiation over the surface of the planet is on the pre-Andean Domeyko Cordillera, a mountain range with elevations between 3,500 and 5,000 m. The regional climate of the Atacama is such that extremely low values of water vapor, cloud cover, ozone, and aerosols concur in this region. The atmospheric transparency in the visible and infrared provided by these conditions, together with a relatively high elevation and low latitude, conspire to produce a region where mean total radiation values exceed 300 W m-2. According to a semiempirical model for surface solar radiation that takes into account extinction by gases, clouds, aerosols, and the effect of topography, the maximum is about 310 ± 15 W m-2, although for individual years, especially those with dry summertime Altiplano conditions, the solar maximum should be located in the Altiplano region near to the Chajnantor Plateau. The delicate combination of elements that concurs in the Atacama region still justifies the increase in observational capabilities of solar radiation and atmospheric composition as it was first devised and executed by the pioneers of solar research in Mount Montezuma in the early twentieth century.405–418396
Modelación y Sistemas de Observación2015Saide, P. E., Mena-Carrasco, M., Tolvett, S., Hernandez, P., & Carmichael, G. R.Air quality forecasting for winter-time PM 2.5 episodes occurring in multiple cities in central and southern ChileJournal of Geophysical Research: Atmospheres10.1002/2015JD023949 air quality degradation due to particles occurs in multiple cities in central and southern Chile during the austral winter reaching levels up to 300–800 µg/m3 hourly PM2.5, which can be associated with severe effects on human health. An air quality prediction system is developed to predict such events in near real time up to 3 days in advance for nine cities with regular air quality monitoring: Santiago, Rancagua, Curicó, Talca, Chillan, Los Ángeles, Temuco, Valdivia, and Osorno. The system uses the Weather Research and Forecasting with Chemistry model configured with a nested 2 km grid-spacing domain to predict weather and inert tracers. The tracers are converted to hourly PM2.5 concentrations using an observationally based calibration which is substantially less computationally intensive than a full chemistry model. The conversion takes into account processes occurring in these cities, including higher likelihood of episode occurrence during weekends and during colder days, the latter related to increased wood-burning-stove activity for heating. The system is calibrated and evaluated for April–August 2014 where it has an overall skill of 53–72% of episodes accurately forecasted (61–76% for the best initialization) which is better than persistence for most stations. Forecasts one, two, and three days in advance all have skill in forecasting events but often present large variability within them due to different meteorological initializations. The system is being implemented in Chile to assist authority decisions not only to warn the population but also to take contingency-based emission restrictions to try to avoid severe pollution events.n/a–n/a1121
Biogeoquímica2015Titschack, J., Baum, D., de Pol-Holz, R., López Correa, M., Forster, N., Flögel, S., … Freiwald, A.Aggradation and carbonate accumulation of Holocene Norwegian cold-water coral reefsSedimentology10.1111/sed.12206 coral ecosystems present common carbonate factories along the Atlantic continental margins, where they can form large reef structures. There is increasing knowledge on their ecology, molecular genetics, environmental controls and threats available. However, information on their carbo-nate production and accumulation is still very limited, even though this information is essential for their evaluation as carbonate sinks. The aim of this study is to provide high-resolution reef aggradation and carbonate accumulation rates for Norwegian cold-water coral reefs from various settings (sunds, inner shelf and shelf margin). Furthermore, it introduces a new approach for the evaluation of the cold-water coral preservation within cold-water coral deposits by computed tomography analysis. This approach allows the differentiation of various kinds of cold-water coral deposits by their macrofossil clast size and orientation signature. The obtained results suggest that preservation of cold-water coral frameworks in living position is favoured by high reef aggradation rates, while preservation of coral rubble prevails by moderate aggradation rates. A high degree of macrofossil fragmentation indicates condensed intervals or unconformities. The observed aggradation rates with up to 1500 cm kyr−1 exhibit the highest rates from cold-water coral reefs so far. Reef aggradation within the studied cores was restricted to the Early and Late Holocene. Available datings of Norwegian cold-water corals support this age pattern for other fjords while, on the shelf, cold-water coral ages are reported additionally from the early Middle Holocene. The obtained mean carbonate accumulation rates of up to 103 g cm−2 kyr−1 exceed previous estimates of cold-water coral reefs by a factor of two to three and by almost one order of magnitude to adjacent sedimentary environments (shelf, slope and deep sea). Only fjord basins locally exhibit carbonate accumulation rates in the range of the cold-water coral reefs. Furthermore, cold-water coral reef carbonate accumulation rates are in the range of tropical reef carbonate accumulation rates. These results clearly suggest the importance of cold-water coral reefs as local, maybe regional to global, carbonate sinks.1873–1898762
Biogeoquímica2015Ugalde, P. C., Santoro, C. M., Gayo, E. M., Latorre, C., Maldonado, S., de Pol-Holz, R., & Jackson, D.How Do Surficial Lithic Assemblages Weather in Arid Environments? A Case Study from the Atacama Desert, Northern ChileGeoarchaeology10.1002/gea.21512 sites composed only of surficial lithics are widespread in arid environments. Numerical dating of such sites is challenging, however, and even establishing a relative chronology can be daunting. One potentially helpful method for assigning relative chronologies is to use lithic weathering, on the assumption that the most weathered artifacts are also the oldest. Yet, few studies have systematically assessed how local environmental processes affect weathering of surficial lithics. Using macroscopic analyses, we compared the weathering of surficial lithic assemblages from seven mid-to-late Holocene archaeological sites sampled from four different microenvironments in the Atacama Desert of northern Chile. Changes in polish, texture, shine, and color were used to establish significant differences in weathering between two kinds of locations: interfluves and canyon sites. Lithics from interfluve sites were moderately to highly weathered by wind and possessed a dark coating, whereas canyon lithics were mildly weathered despite greater exposure to moisture, often lacked indications of eolian abrasion, and lacked dark coatings. Our results show that lithic weathering can be used as a proxy for relative age, but only after considering local environmental factors. The power of such chronologies can be improved by combining archaeological, paleoenvironmental, geomorphological, and taphonomic data.352–368430
Servicios Ecosistémicos2015Urrutia-Jalabert, R., Malhi, Y., Barichivich, J., Lara, A., Delgado-Huertas, A., Rodríguez, C. G., & Cuq, E.Increased water use efficiency but contrasting tree growth patterns in Fitzroya cupressoides forests of southern Chile during recent decadesJournal of Geophysical Research: Biogeosciences10.1002/2015JG003098 is known about how old-growth and massive forests are responding to environmental change. We investigated tree-ring growth and carbon isotopes of the long-lived and high biomass Fitzroya cupressoides in two stands growing in contrasting environmental conditions in the Coastal Range (∼300 years old) and Andean Cordilleras (>1500 years old) of southern Chile. The interannual variability in δ13C was assessed for the period 1800–2010, and changes in discrimination and intrinsic water use efficiency (iWUE) were evaluated in relation to changes in climate and tree-ring growth during the last century. 13C discrimination has significantly decreased, and iWUE has increased since the 1900s in both sites. However, these trends in isotopic composition have been accompanied by different growth patterns: decreasing growth rates in the Coastal Range since the 1970s and increasing growth rates in the Andes since the 1900s. Trees growing in the Coastal Range have become more efficient in their use of water, probably due to reduced stomatal conductance caused by increases in CO2 and warming. Trees growing in the Andes have also become more water use efficient, but this has been likely due to increased photosynthetic rates. Fitzroya forests, including particularly old-growth stands, are responding to recent environmental changes, and their response has been site dependent. The growth of forests under a more Mediterranean climate influence and restrictive soil conditions in the Coastal Range has been more negatively affected by current warming and drying; while the growth of old stands in thewet Andes has been positively affected by changes in climate (decreasing cloudiness) and increasing CO2. Permanent monitoring of these endangered forests under ongoing environmental changes is needed in order to reassure the long-term preservation of this millennial-aged species.2505–252412120
Servicios Ecosistémicos2015Urrutia-Jalabert, R., Malhi, Y., & Lara, A.The Oldest , Slowest Rainforests in the World ? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests inPloS one10.5061/dryad.2kh91 temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP), carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC) in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA) in the Andean Cordillera. Aboveground live biomass was 113-114 Mg C ha(-1) and 448-517 Mg C ha(-1) in AC and AA, respectively. Aboveground productivity was 3.35-3.36 Mg C ha(-1) year(-1) in AC and 2.22-2.54 Mg C ha(-1) year(-1) in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21-4.24 and 3.78-4.10 Mg C ha(-1) year(-1) in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539-640 years for the whole forest in the Andes and 1368-1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia.1–24910
Servicios Ecosistémicos2015Urrutia-Jalabert, R., Rossi, S., Deslauriers, A., Malhi, Y., & Lara, A.Environmental correlates of stem radius change in the endangered Fitzroya cupressoides forests of southern ChileAgricultural and Forest Meteorology10.1016/j.agrformet.2014.10.001 between environmental factors and stem radius variation at short temporal scales can provide useful information regarding the sensitivity of tree species' productivity to climate change. This study used automatic point dendrometers to assess the relationship between environmental variables and stem radius contraction and increment in ten Fitzroya cupressoides trees growing in two sites, the Coastal Range (Alerce Costero National Park) and the Andean Cordillera (Alerce Andino National Park) of southern Chile. The growing season in each site, determined using stem daily cycle patterns for each month, was longer in the Coastal Range site than in the Andes. Warmer and sunnier conditions were positively related with daytime tree radius contraction in both areas, and relationships were stronger in the Coastal Range site where more pronounced shrinking events were associated with prolonged warm and dry conditions compared to the Andes. Stem increment was positively related with precipitation and humidity in both sites, reflecting the positive effect of water on cell turgidity and consequent enlargement. Relationships between stem radius change and environmental variables considering longer temporal scales (7 to 31 days), confirmed a stronger association with humidity/vapor pressure deficit and precipitation, rather than with temperature. Although Fitzroya grows in particularly wet and cool areas, current and projected drier and warmer summer conditions in southern Chile may have a negative effect on Fitzroya stem increment and carbon accumulation in both sites. This effect would be more critical in the Coastal Range compared with the Andes though, due in part to more limiting soil conditions and less summer precipitation in this area. Long-term research is needed to monitor different aspects of the response of these endangered ecosystems to this additional threat imposed by climate change.209–221200
Biogeoquímica2015Valenzuela, D., Santoro, C. M., Capriles, J. M., Quinteros, M. J., Peredo, R., Gayo, E. M., … Sepúlveda, M.Consumption of animals beyond diet in the Atacama Desert, northern Chile (13,000–410BP): Comparing rock art motifs and archaeofaunal recordsJournal of Anthropological Archaeology10.1016/j.jaa.2015.09.004 relations between humans and animals extend into socio-cultural aspects that go beyond the mere acquisition of food, meaning that animals constitute cultural resources that fulfill diverse roles in social and cultural systems. Visual images in different media, including rock art, represent one of the ways in which these complex relationships take place. While in the New World few comparative analyses of archaeofaunal and visual data have been addressed, in the Old World these studies have been framed by a dichotomist view between drawn (thought) and consumed (eaten) understanding, both terms as separate and disconnected social realms. This view also structures an abstract, non-pragmatic, rather passive, world drawn in art, against a concrete, practical, active world of consumption. The analysis we present here, based on principles of substantive economy theory, explores the relation between humans and animals in the prehistory of the Atacama Desert (ca. 13,000-410. BP), by comparing visual images of fauna depicted in rock art (engravings and paintings) with archaeofaunal remains from domestic and funerary contexts. The dataset (comprised of 1534 archaeofaunal items and 729 rock art animal motifs from 117 sites) was standardized by calculating the percentage of ubiquity of each animal item per period of time, using Spearman's rank correlation coefficients to identify synchronic and diachronic changes in the relative importance of certain animals consumed. We observed important temporal and contextual variations in the consumption of animals drawn in rock art in the Atacama Desert, and we conclude that they reflect a selection of a wide range of ritual and utilitarian, but not mutually exclusive, functions. In particular, images of camelids emphasized the importance of providing fiber for the creation of textile artifacts and camelid use as pack animals in the caravan trade, both activities that were fundamental in the economy of local societies.250–26540
Dinámica del Clima2015Viale, M., & Garreaud, R.Orographic effects of the subtropical and extratropical Andes on upwind precipitating cloudsJournal of Geophysical Research: Atmospheres10.1002/2014JD023014.Received orographic effect of the Andes (30°S–55°S) on upwind precipitating clouds from midlatitude frontal systems is investigated using surface and satellite data. Rain gauges between 33°S and 44°S indicate that annual precipitation increases from the Pacific coast to the windward slopes by a factor of 1.8 ± 0.3. Hourly gauges and instantaneous satellite estimates reveal that the cross-barrier increase in annual precipitation responds to an increase in both the intensity and frequency of precipitation. CloudSat satellite data indicate that orographic effects of the Andes on precipitating ice clouds increase gradually from midlatitudes to subtropics, likely as a result of a reduction of synoptic forcing and an increase of the height of the Andes equatorward. To the south of 40°S, the thickness of clouds slightly decreases from offshore to the Andes. The total ice content increases substantially from the open ocean to the coastal zone (except to the south of 50°S, where there is no much variation over the ocean), and then experience little changes in the cross-mountain direction over the upstream and upslope sectors. Nevertheless, the maximum ice content over the upslope sector is larger and occurs at a lower level than their upwind counterparts. In the subtropics, the offshore clouds contain almost no ice, but the total and maximum ice content significantly increases toward the Andes, with values being much larger than their counterparts over the extratropical Andes. Further, the largest amounts of cloud ice are observed upstream of the tallest Andes, suggesting that upstream blocking dominates there.1–1310120
Dinámica del Clima2015Vuille, M., Franquist, E., Garreaud, R., Sven, W., Casimiro, L., Cáceres, B., … Cáceres, B.Impact of the global warming hiatus on Andean temperatureJournal of Geophysical Research: Atmospheres10.1002/2015JD023126.Received recent hiatus in global warming is likely to be reflected in Andean temperature, given its close dependence on tropical Pacific sea surface temperature (SST). While recent work in the subtropical Andes has indeed documented a cooling along coastal areas, trends in the tropical Andes show continued warming. Here we analyze spatiotemporal temperature variability along the western side of the Andes with a dense station network updated to 2010 and investigate its linkages to tropical Pacific modes of variability. Results indicate that the warming in tropical latitudes has come to a halt and that the subtropical regions continue to experience cooling. Trends, however, are highly dependent on elevation. While coastal regions experience cooling, higher elevations continue to warm. The coastal cooling is consistent with the observed Pacific Decadal Oscillation (PDO) fingerprint and can be accurately simulated using a simple PDO-analog model. Much of the PDO imprint is modulated and transmitted through adjustments in coastal SST off western South America. At inland and higher-elevation locations, however, temperature trends start to diverge from this PDO-analog model in the late 1980s and have by now emerged above the 1σ model spread. Future warming at higher elevation is likely and will contribute to further vertical stratification of atmospheric temperature trends. In coastal locations, future warming or cooling will depend on the potential future intensification of the South Pacific anticyclone but also on continued temperature dependence on the state of the PDO. ©2015.3745–37579120
Modelación y Sistemas de Observación2016Albrecht, F., & Shaffer, G.Regional Sea-Level Change along the Chilean Coast in the 21st centuryJournal of Coastal Research10.2112/JCOASTRES-D-15-00192.1 sea-level change for Chile is considered until the end of the 21st century for the RCP4.5 and RCP8.5 scenarios. The main components that contribute to sea-level change are analyzed and summed to achieve a total estimate of sea-level change along the coast of Chile and in the Southeast Pacific. Included are the steric/dynamic component, the contribution from land ice loss and the sea- level change due to the glacial isostatic adjustment. Regional fingerprints and global means are combined to estimate sea-level change in this area. For the steric/dynamic component two different estimates are considered. The results are compared to those found in the IPCC AR5 report. The total mean sea-level rise along the coast lies between 34 cm and 52 cm for the RCP4.5 scenario and between 46 cm and 74 cm for the RCP8.5 scenario, depending on the location and the steric/dynamic component estimate considered. This component is the main contribution in each scenario. All estimates show a modest, relatively constant decrease in sea-level rise along the coast from north to south.X
Dimensión Humana2016Aldunce, P., Beilin, R., Handmer, J., & Howden, M.Stakeholder participation in building resilience to disasters in a changing climateEnvironmental Hazards10.1080/17477891.2015.1134427 resilience perspective has emerged as a plausible approach to confront the increasingly devastating impacts of disasters; and the challenges and uncertainty climate change poses through an expected rise in frequency and magnitude of hazards. Stakeholder participation is posited as pivotal for building resilience, and resilience is not passive; rather, stakeholders are actively involved in the process of building resilience. Who is involved and how they are involved are crucial aspects for developing resilience in practice. Nevertheless, there are few empirical studies available to inform theory or show how these issues are addressed. This study focuses on revealing how practitioners frame the issue of participation in relation to resilience, its relevance to a changing climate and how, in consequence, they construct practices. Using Hajer's [(1995). The politics of environmental discourse: Ecological modernization and the policy process. New York] ‘Social-interactive discourse theory’, in this...1–16
Dimensión Humana2016Aldunce, P., Handmer, J., Beilin, R., & Howden, M.Is climate change framed as 'business as usual or as a challenging issue? The practitioners dilemmaEnvironment and Planning C: Government and Policy10.1177/0263774X15614734 is growing recognition that routine climate change framing is insufficient for addressing the challenges presented by this change, and that different framings of climate change shape stakeholders' practices and guide policy options. This research investigated how stakeholders conceptualise climate change in terms of its seriousness and related uncertainty, and a resilience approach as a possible policy option to confront this uncertainty. An application of the conceptual framework provided by Handmer and Dovers' typology of emergencies is novel to the climate change field. Results show that there is a tendency to frame climate change as complex (with uncertainty representing part of that complexity) and to confront this complexity with less complex policies and solutions. No pattern of a conceptual link between uncertainty and resilience was observed. The results presented in this study offer empirical evidence to inform theory and provide helpful insights to inform policy design and practice.0263774X15614734
Biogeoquímica2016Cordova, A. M., Arévalo, J., Marín, J. C., Baumgardner, D., Graciela B. Raga, G. B. R., Pozo, D., … Rondanelli, R.On the Transport of Urban Pollution in an Andean Mountain ValleyAerosol and Air Quality Research10.4209/aaqr.2015.05.0371 pollution can often impact surrounding, non-urban regions, through advection and dispersal of pollutants by the prevailing winds. Urban regions located upstream of high mountains, such as the Andes, can potentially impact the cryosphere by deposition of particles onto the surface of the snowpack and glaciers. Santiago, the capital of Chile, has more than 6 million inhabitants and regularly experiences episodes of severe pollution, particularly during the austral winter. Some studies have hypothesized that particle pollution from Santiago can reach the cryosphere downwind of the city, but the scarcity of measurements made high in the mountains prevents the validation of mesoscale models so the proof of actual impact remains elusive. A research project was designed to provide some insight into this question. The Pollution Impact on Snow in the Cordillera - Experiments and Simulations (PISCES) project was carried out in 2014 and includes both observational and modeling components. A five-week field campaign was conducted at the end of winter, at an elevated site in a mountain valley, 65 km to the southeast of the center of Santiago, to characterize some aspects of particulate pollution. During synoptic conditions that result in clear days at the site, the mesoscale mountain-valley circulation is effective in transporting pollutants upwards during the day, leading to diluted particle concentrations beyond the summits of the highest peaks. Cloudy days with reduced up-valley circulation do not show increased concentrations associated with transport. Back trajectories indicate that airmasses reaching the site during the field campaign are seldom influenced by pollution from Santiago.593-605316
Servicios Ecosistémicos2016Delgado-Baquerizo, M., Maestre, F. T., Gallardo, A., Eldridge, D. J., Soliveres, S., Bowker, M. A., Gómez-González, S., … Zaady, E.Human impacts and aridity differentially alter soil N availability in drylands worldwideGlobal Ecology and Biogeography10.1111/geb.12382 Climate and human impacts are changing the nitrogen (N) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We con- ducted a global observational study to evaluate how aridity and human impacts, together with biotic and abiotic factors, affect key soil variables of the N cycle. Location Two hundred and twenty-four dryland sites from all continents except Antarctica widely differing in their environmental conditions and human influence. Methods Using a standardized field survey, we measured aridity, human impacts (i.e. proxies of land uses and air pollution), key biophysical vari- ables (i.e. soil pH and texture and total plant cover) and six important variables related to N cycling in soils: total N, organic N, ammonium, nitrate, dissolved organic:inorganic N and N mineralization rates.We used structural equation modelling to assess the direct and indirect effects of aridity, human impacts and key biophysical variables on the N cycle. Results Human impacts increased the concentration of total N, while aridity reduced it. The effects of aridity and human impacts on the N cycle were spatially disconnected,whichmay favour scarcity of Nin the most arid areas and promote its accumulation in the least arid areas. Main conclusions We found that increasing aridity and anthropogenic pressure are spatially disconnected in drylands. This implies that while places with low aridity and high human impact accumulate N, most arid sites with the lowest human impacts lose N. Our analyses also provide evidence that both increasing aridity and human impacts may enhance the relative dominance of inorganicNin dryland soils, having a negative impact on key functions and services provided by these ecosystems.36–45125
Servicios Ecosistémicos2016Díaz-Hormazábal, I., & González, M. E.Análisis espacio-temporal de incendios forestales en la región del Maule, ChileBosque10.4067/S0717-92002016000100014 las últimas décadas, los incendios forestales han sido una preocupación en distintas regiones del mundo, especialmente por el incremento en su ocurrencia producto de actividades humanas y cambios en el clima. En este estudio se examinaron las tendencias espacio-temporales en la ocurrencia y superficie afectada por incendios en la región del Maule durante el período 1986-2012. Se utilizó la base de datos de incendios de la Corporación Nacional Forestal, cuyos registros fueron representados espacialmente mediante una grilla de 2x2 km. La ocurrencia se mantuvo estable durante el periodo analizado con un promedio de 378 eventos por año. La superficie quemada presentó tres periodos por sobre el promedio de 5.273 hectáreas al año. La mayor parte de los incendios afectó superficies <5ha, mientras que un número muy pequeño de eventos explicaron la mayor parte del área quemada anualmente en la región. Según el combustible de inicio, aumentaron aquellos eventos iniciados en plantaciones forestales y disminuyeron aquellos originados en bosque nativo. Las causas de incendios asociadas al tránsito y al transporte resultaron ser las más importantes. El número de eventos causados accidentalmente por quema de desechos aumentó significativamente en el periodo estudiado. La mayor parte de los incendios se localiza en la zona costera y en el llano central, fuertemente asociados a la red vial y a las ciudades más pobladas. Este trabajo es una contribución a la caracterización de los incendios forestales en la región del Maule, representando las estadísticas de incendios de forma espacialmente explícita.147-158137
Servicios Ecosistémicos2016Lopatin, J., Dolos, K., Hernández, H. J., Galleguillos, M., & Fassnacht, F. E.Comparing Generalized Linear Models and random forest to model vascular plant species richness using LiDAR data in a natural forest in central ChileRemote Sensing of Environment10.1016/j.rse.2015.11.029 is considered to be an essential element of the Earth system, driving important ecosystem services. However, the conservation of biodiversity in a quickly changingworld is a challenging task which requires cost- efficient and precise monitoring systems. In the present study, the suitability of airborne discrete-return LiDAR data for the mapping of vascular plant species richness within a Sub-Mediterranean second growth native forest ecosystemwas examined. The vascular plant richness of four different layers (total, tree, shrub andherb richness) was modeled using twelve LiDAR-derived variables. As species richness values are typically count data, the cor- responding asymmetry and heteroscedasticity in the error distribution has to be considered. In this context,we compared the suitability of randomforest (RF) and a Generalized Linear Model (GLM)with a negative binomial error distribution. Both models were coupled with a feature selection approach to identify the most relevant LiDAR predictors and keep the models parsimonious. The results of RF and GLM agreed that the three most im- portant predictors for all four layers were altitude above sea level, standard deviation of slope and mean canopy height. Thiswas consistent with the preconception of LiDAR's suitability for estimating species richness,which is its capacity to capture three types of information: micro-topographical, macro-topographical and canopy struc- tural. Generalized LinearModels showed higher performances (r2: 0.66, 0.50, 0.52, 0.50; nRMSE: 16.29%, 19.08%, 17.89%, 21.31% for total, tree, shrub and herb richness respectively) than RF (r2: 0.55, 0.33, 0.45, 0.46; nRMSE: 18.30%, 21.90%, 18.95%, 21.00% for total, tree, shrub and herb richness, respectively). Furthermore, the results of the best GLMweremore parsimonious (three predictors) and less biased than the best RFmodels (twelve pre- dictors). We think that this is due to the mentioned non-symmetric error distribution of the species richness values, which RF is unable to properly capture. Fromanecological perspective, thepredicted patterns agreedwell with theknown vegetationcomposition of the area. We found especially high species numbers at low elevations and along riversides. In these areas, overlap- ping distributions of thermopile sclerophyllos species,water demanding Valdivian evergreen species and species growing in Nothofagus obliqua forests occur. The three main conclusions of the study are: 1) appropriatemodel selection is crucialwhenworkingwith biodiver- sitycountdata; 2) the applicationofRFfordatawithnon-symmetricerrordistributions isquestionable; and3) struc- tural and topographic information derived fromLiDAR data is useful for predicting local plant species richness. ©200–210December 2015173
Modelación y Sistemas de Observación2016Rojas, M., Mac-Lean, C., Morales, J., Monares, A., & Fustos, R.Climate change education and literacy at the Faculty of Physical and Mathematical Sciences of the University of ChileInt. J. Global Warming the role that higher education institutions (HEIs) play in terms of catalysing change within societies, over the past years, sustainability initiatives within HEIs have flourished worldwide. Likewise, the scientific evidence of anthropogenic climate change has been on the political and academic agenda for decades, thus, the importance of ameliorating climate change education and literacy both at the society and university training levels. Accordingly, certain questions arise: What are the most effective current climate change educational methodologies? Which road map would be the most appropriate to be suggested to HEIs to promote climate change literacy for future professionals? In order to begin addressing these questions, the Faculty of Mathematical and Physical Sciences of the University of Chile (FCFM) approach to climate change teaching and literacy is here described. The later contemplates the history of the institutionalisation of sustainability at the FCFM, collection of courses and minors for students which incorporate climate change related-topics, as well as climate change related research centres. Keywords:X
Servicios Ecosistémicos2016Swanson F., Jones, J., Crisafulli, C., González, M. E., & Lara, A.Puyehue-Cordón Caulle eruption of 2011: tephra fall and initial forest responses in the Chilean AndesBosque10.4067/S0717-92002016000100009 2011 eruption in the Puyehue-Cordón Caulle volcanic complex deposited up to 50 cm of tephra in a plume that intersected the crest of the Andes along Route 215, offering an excellent opportunity to study disturbance effects on native forests along a gradient of tephra depth. Our observations focused on short-term, species-level, tree mortality and sprouting and tephra fall effects on foliage and limb fall. More than 80 % of the thickest deposits were composed of a basal, pumice, gravel layer containing individual clasts up to 6 cm in length overlain by finer gravel and capped by several cm of sandy tephra. In a sample of four plots with tephra thickness ranging from 10 to 50 cm, we observed a wide range of tree mortality: about 8 % of stems living at the time of the eruption were killed by 10 cm of tephra fall and 54 % were killed by 50 cm. However, properties of the affected forest, such as species composition, foliage sprouting and retention (deciduous 23 versus evergreen) characteristics, and tree size/age, strongly influenced survival. The sites with 35 and 50 cm thick deposits were dominated by the deciduous tree Nothofagus pumilio, which was leafless in the austral winter season of the initial phase of the eruption. The evergreen tree N. dombeyi experienced much greater mortality. The low density of the falling pumice particles appeared to cause minimal abrasion of the canopy.85-96137
Servicios Ecosistémicos2016Veblen, T., González, M. E., Stewart, G., Kitzberger, T., & Brunet, J.Tectonic ecology of the temperate forests of South America and New ZealandNew Zealand Journal of Botany10.1080/0028825X.2015.1130726 disturbances triggered by earthquakes and volcanic eruptions are of fundamental importance in structuring the temperate forests of southwestern South America and New Zealand. We review studies of the ecological effects of these tectonic phenomena and how they have been central to progress in the modern development of forest ecology in both regions. Studies of tectonic influences on the dynamics of southern temperate rainforests of Chile and New Zealand published in the 1970s and early 1980s contributed prominently to the shift away from the equilibrium paradigms dominant globally in the 1960s and towards modern non- equilibrium frameworks of forest dynamics. Empirical studies of tectonic ecology in these temperate forests in combination with critical evaluations of earlier successional theory have significantly advanced understanding of the roles of coarse scale disturbance in the dynamics of forests in southwestern South America and New Zealand. Recognition that cohort forest For Peer Review Only structures triggered by exogenous disturbances such as wind storms and tectonic events are the norm rather than all-aged structures has been of fundamental importance to understanding the dynamics of these forests. The non-equilibrium patch dynamics framework for interpreting forest structure and dynamics bolstered by tectonic ecology studies in southern South America and New Zealand was of key importance in refining older views of these forests as being out of equilibrium with contemporary climate, revising understanding of the effects of introduced browsing animals on forest structure, and guiding the development of appropriate forest management practices.X
Dimensión Humana2016Aldunce, P., Bórquez, R., Adler, C., Blanco, G., & Garreaud, R. Unpacking Resilience for Adaptation: Incorporating Practitioners’ Experiences through a Transdisciplinary Approach to the Case of Drought in ChileSustainability10.3390/su8090905 debate on the implementation of resilience in addressing climatic impacts calls for more pragmatic means of reducing losses. In this study we aimed to generate context-specific knowledge about resilience factors for addressing the impacts of drought, with the expectation that bringing forth experiential knowledge on how impacts were addressed in the past would shed light on what constitutes key resilience factors for practitioners working in urban contexts. The study was carried in three of the largest cities in Chile: Santiago, Concepción, and Valdivia. The analytical framework consists of urban and regional resilience incorporating transdisciplinary approaches applying the Resilience-Wheel tool, combined with participatory methods for the co-production of knowledge and qualitative content analysis of documents and workshops. Results show that key determinants of building resilience to drought were: improving education and access to information, enhancing preparedness, promoting technology transfer, reinforcing organizational linkages and collaboration, decentralizing governance, and encouraging citizen participation. The Resilience-Wheel was useful for navigating the conceptual complexity and diversity of perspectives inherent among social actors. The transdisciplinary approach allowed us to co-produce key knowledge that can be applied to build resilience in future, through a bottom-up approach that bridges the science–policy interface.90598
Servicios Ecosistémicos2016Alvarez-Garreton, C., Ryu, D., Western, A. W., Crow, W. T., Su, C.-H., & Robertson, D. R. Dual assimilation of satellite soil moisture to improve streamflow prediction in data-scarce catchmentsWater Resources Research10.1002/2015WR018429 paper explores the use of active and passive microwave satellite soil moisture products for improving streamflow prediction within four large (>5000km2) semiarid catchments in Australia. We use the probability distributed model (PDM) under a data-scarce scenario and aim at correcting two key controlling factors in the streamflow generation: the rainfall forcing data and the catchment wetness condition. The soil moisture analysis rainfall tool (SMART) is used to correct a near real-time satellite rainfall product (forcing correction scheme) and an ensemble Kalman filter is used to correct the PDM soil moisture state (state correction scheme). These two schemes are combined in a dual correction scheme and we assess the relative improvements of each. Our results demonstrate that the quality of the satellite rainfall product is improved by SMART during moderate-to-high daily rainfall events, which in turn leads to improved streamflow prediction during high flows. When employed individually, the soil moisture state correction scheme generally outperforms the rainfall correction scheme, especially for low flows. Overall, the combined dual correction scheme further improves the streamflow predictions (reduction in root mean square error and false alarm ratio, and increase in correlation coefficient and Nash-Sutcliffe efficiency). Our results provide new evidence of the value of satellite soil moisture observations within data-scarce regions. We also identify a number of challenges and limitations within the schemes.5357-5375752
Modelación y Sistemas de Observación2016Andrade-Flores, M., Rojas, N., Melamed, M. L., Mayol-Bracero, O. L., Dawidowski, L., Gallardo, L., … Huneeus, N. Fostering a Collaborative Atmospheric Chemistry Research Community in the Latin America and Caribbean RegionBulletin of the American Meteorological Society10.1175/BAMS-D-14-00267.1 2013, the international Commission on Atmospheric Chemistry and Global Pollution (iCACGP) and the International Global Atmospheric Chemistry (IGAC) Project Americas Working Group (iCACGP/IGAC AWG) was formed to build a cohesive network and foster the next generation of atmospheric scientists with the goal of contributing to a scientific community focused on building collective knowledge for the Americas. The Latin America–Caribbean (LAC) region shares common history, culture, and socioeconomic issues but, at the same time, it is highly diverse in its physical and human geography. The LAC region is unique because approximately 80% of its population lives in urban areas, resulting in high-density hotspots of urbanization and vast unpopulated rural areas. In recent years, most countries of the region have experienced rapid growth in population and industrialization as their economies emerge. The rapid urbanization, the associated increases in mobile and industrial sources, and the growth of the agricultural activities related to biomass burning have degraded air quality in certain areas of the LAC region. Air pollution has negative implications for human health, ecosystems, and climate. In addition, air pollution and the warming caused by greenhouse gases could impact the melting of Andean glaciers, an important source of freshwater. To better understand the links between air pollution and climate, it is necessary to increase the number of atmospheric scientists and improve our observational, analytical, and modeling capacities. This requires sustained and prioritized funding as well as stronger collaboration within the LAC region.1929-19391097
Biogeoquímica2016Barrett, B. S., Campos, D. A., Veloso, J. V., & Rondanelli, R. Extreme temperature and precipitation events in March 2015 in central and northern ChileJournal of Geophysical Research: Atmospheres10.1002/2016JD024835 18 to 27 March 2015, northern, central, and southern Chile experienced a series of extreme hydrometeorological events. First, the highest surface air temperature ever recorded in Santiago (with reliable records dating to 1877), 36.8°C at Quinta Normal, was measured at 15:47 local time on 20 March 2015. Immediately following this high heat event, an extreme precipitation event, with damaging streamflows from precipitation totals greater than 45 mm, occurred in the semiarid and hyperarid Atacama regions. Finally, concurrent with the heavy precipitation event, extremely warm temperatures were recorded throughout southern Chile. These events were examined from a synoptic perspective with the goal of identifying forcing mechanisms and potential interaction between each analysis which provides operational context by which to identify and predict similar events in the future. Primary findings were as follows: (1) record warm temperatures in central Chile resulted from anomalous lower troposphere ridging and easterly downslope flow, both of which developed in response to an anomalous midtroposphere ridge-trough pattern; (2) a cutoff low with anomalous heights near one standard deviation below normal slowly moved east and was steered ashore near 25°S by circulation around a very strong ridge (anomalies more than 3 standard deviations above normal) centered near 60°S; (3) anomalously high precipitable water content (20 mm above climatological norms) over the Peruvian Bight region was advected southward and eastward ahead of the cutoff low by low-level northwesterly flow, greatly enhancing observed precipitation over northern Chile.2016JD0248359121
Modelación y Sistemas de Observación2016Berman, A. L., Silvestri, G. E., Rojas, M., & Tonello, M. S. Accelerated greenhouse gases versus slow insolation forcing induced climate changes in southern South America since the Mid-HoloceneClimate Dynamics10.1007/s00382-016-3081-z paper is a pioneering analysis of past climates in southern South America combining multiproxy reconstructions and the state-of-the-art CMIP5/PMIP3 paleoclimatic models to investigate the time evolution of regional climatic conditions from the Mid-Holocene (MH) to the present. This analysis allows a comparison between the impact of the long term climate variations associated with insolation changes and the more recent effects of anthropogenic forcing on the region. The PMIP3 multimodel experiments suggest that changes in precipitation over almost all southern South America between MH and pre-industrial (PI) times due to insolation variations are significantly larger than those between PI and the present, which are due to changes in greenhouse gas concentrations. Anthropogenic forcing has been particularly intense over western Patagonia inducing reduction of precipitation in summer, autumn and winter as a consequence of progressively weaker westerly winds over the region, which have moved further poleward, between ca. 35–55°S and have become stronger south of about 50°S. Orbital variations between the MH to the PI period increased insolation over southern South America during summer and autumn inducing warmer conditions in the PI, accentuated by the effect of anthropogenic forcing during the last century. On the other hand, changes in orbital parameters from the MH to the PI period reduced insolation during winter and spring inducing colder conditions, which have been reversed by the anthropogenic forcing.
Dinámica del Clima2016Blunden, J., & Arndt, D. S. (Barichivich, J. co-author of Chapter 2 Section 9)State of the Climate in 2015Bulletin of the American Meteorological Society10.1175/2016BAMSStateoftheClimate.1 2. GLOBAL CLIMATE, Section 9. Monitoring global drought using the self-calibrating Palmer drought severity index. J. Osborn., J. Barichivich, I. Harris,
G. van der Schrier, and P. D. Jones
Dimensión Humana2017Borquez, R., Aldunce, P., & Adler, C. Resilience to climate change: from theory to practice through co-production of knowledge in ChileSustainability Science10.1007/s11625-016-0400-6 theory, building resilience is touted as one way to deal with climate change impacts; however, in practice, there is a need to examine how contexts influence the capacity of building resilience. A participatory process was carried out through workshops in regions affected by drought in Chile in 2014. The aim was to explore how resilience theory can be better applied and articulated into practice vis-á-vis participatory approaches that enrich the research process through the incorporation of co-produced. The results show that there are more differences in responses by type of actor than between regions, where issues of national interest, such as ‘education-information’ and ‘preparedness’, are highlighted over others. However, historically relevant local topics emerged as differentiators: decentralisation, and political will. This reinforces why special attention must be given to the different understandings in knowledge co-production processes. This study provides evidence and lessons on the importance of incorporating processes of the co-production of knowledge as a means to better articulate and transfer abstract concepts, such as resilience theory, into practice.163-176112
Biogeoquímica; Dinámica del Clima2016Bozkurt, D., Rondanelli, R., Garreaud, R., & Arriagada, A. Impact of warmer eastern tropical Pacific SST on the March 2015 Atacama floodsMonthly Weather Review10.1175/MWR-D-16-0041.1 Chile hosts the driest place on Earth in the Atacama Desert. Nonetheless, an extreme precipitation event affected the region on 24-26 March 2015 with 1-day accumulated precipitation exceeding 40 mm in several locations and hourly mean rainfall rates higher than 10 mm h−1, producing floods and resulting in casualties and significant damage. The event is analyzed using ERA-Interim reanalysis, surface station data, sounding observations and satellite based radar. Two main conditions favorable for precipitation were present at the time of the event: (i) a cut-off low (COL) off the coast of Northern Chile and (ii) positive sea surface temperature (SST) anomalies over the eastern tropical Pacific. The circulation driven by the COL was strong but not extraordinary. A regional climate model (RegCM4) is used to test the sensitivity of precipitation to SST anomalies by removing the warm SST anomaly in the eastern tropical Pacific. The cooler simulation produced a very similar COL dry dynamics than that simulated in a control run (with observed SST), but, suppressed the precipitation by 60-80% over Northern Chile and 100% in parts of the Atacama Desert due to the decreased availability of precipitable water. The results indicate that the warm SST anomaly over eastern Pacific, favored by the onset of El Niño 2015-2016, was instrumental to the extreme precipitation event by providing an anomalous source of water vapor transported to Atacama by the circulation ahead of the COL.
Modelación y Sistemas de Observación2016Brasseur, G. P., & Gallardo, L. Climate Services: Lessons Learned and Future ProspectsEarth's Future10.1002/2015EF000338 perspective paper reviews progress made in the last decades to enhance the communication and use of climate information relevant to the political and economic decision process. It focuses, specifically, on the creation and development of climate services, and highlights a number of difficulties that have limited the success of these services. Among them are the insufficient awareness by societal actors of their vulnerability to climate change, the lack of relevant products and services offered by the scientific community, the inappropriate format in which the information is provided, and the inadequate business model adopted by climate services. The authors suggest that, to be effective, centers should host within the same center a diversity of staff including experts in climate science, specialists in impact, adaptation and vulnerability, representatives of the corporate world, agents of the public service as well as social managers and communication specialists. The role and importance of environmental engineering is emphasized.
Servicios Ecosistémicos2016Cabezas, J., Galleguillos, M., & Perez-Quezada, J. F. Predicting Vascular Plant Richness in a Heterogeneous Wetland Using Spectral and Textural Features and a Random Forest AlgorithmIEEE Geoscience and Remote Sensing Letters10.1109/LGRS.2016.2532743 method to predict vascular plant richness using spectral and textural variables in a heterogeneous wetland is presented. Plant richness was measured at 44 sampling plots in a 16-ha anthropogenic peatland. Several spectral indices, first-order statistics (median and standard deviation), and second-order statistics [metrics of a gray-level co-occurrence matrix (GLCM)] were extracted from a Landsat 8 Operational Land Imager image and a Pleiades 1B image. We selected the most important variables for predicting richness using recursive feature elimination and then built a model using random forest regression. The final model was based on only two textural variables obtained from the GLCM and derived from the Landsat 8 image. An accurate predictive capability was reported ( R2=0.6; [Formula: see text]), highlighting the possibility of obtaining parsimonious models using textural variables. In addition, the results showed that the mid-resolution Landsat 8 image provided better predictors of richness than the high-resolution Pleiades image. This is the first study to generate a model for plant richness in a wetland ecosystem.646-650513
Servicios Ecosistémicos2016Carlón Allende, T., Mendoza, M. E., Pérez-Salicrup, D. R., Villanueva-Díaz, J., & Lara, A. Climatic responses of Pinus pseudostrobus and Abies religiosa in the Monarch Butterfly Biosphere Reserve, Central MexicoDendrochronologia10.1016/j.dendro.2016.04.002 the effects of climate on the growth of trees is important to project the response of forests to climate change. Dendrochronological analysis offers a “proxy” source for the effects of climatic variation on tree growth at different spatial and temporal scales. To examine influences of temperature and precipitation on radial growth of Pinus pseudostrobus and Abies religiosa, this study combines measurements of radial growth patterns of forest trees in the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico with temperature and precipitation variables from instrumental records. Dendrochronological samples were collected as cross sections and increment cores by using a chainsaw and increment borers, respectively. Total ring-width chronologies were developed for each site. Principal component analyses (PCA) were used to identify common temperature, precipitation and tree growth variation patterns. Correlation and response function analyses between chronologies and records of temperature and precipitation were used to evaluate the relation of climate variables on tree growth. The months during which tree growth was most strongly affected by precipitation were January, February and October from the previous year; only the temperature of September from the previous year affected the tree growth. In some chronologies, May’s average monthly maximum temperature was negatively correlated with tree growth. PCA and a comparison of PCA factor scores of climatic variables and chronologies showed no significant differences between northern, central or southern portions of the MBBR. Apparently, tree growth in the MBBR is reduced in years of low January–May precipitation combined with high summer (September of the previous year) temperatures, a scenario which is likely to occur as a consequence of global climate change.103-11638
Biogeoquímica2016Cordero, R. R., Damiani, A., Seckmeyer, G., Jorquera, J., Caballero, M., Rondanelli, R., … Laroze, D. The Solar Spectrum in the Atacama DesertScientific Reports10.1038/srep22457 Atacama Desert has been pointed out as one of the places on earth where the highest surface irradiance may occur. This area is characterized by its high altitude, prevalent cloudless conditions and relatively low columns of ozone and water vapor. Aimed at the characterization of the solar spectrum in the Atacama Desert, we carried out in February-March 2015 ground-based measurements of the spectral irradiance (from the ultraviolet to the near infrared) at seven locations that ranged from the city of Antofagasta (on the southern pacific coastline) to the Chajnantor Plateau (5,100 m altitude). Our spectral measurements allowed us to retrieve the total ozone column, the precipitable water, and the aerosol properties at each location. We found that changes in these parameters, as well as the shorter optical path length at high-altitude locations, lead to significant increases in the surface irradiance with the altitude. Our measurements show that, in the range 0–5100 m altitude, surface irradiance increases with the altitude by about 27% in the infrared range, 6% in the visible range, and 20% in the ultraviolet range. Spectral measurements carried out at the Izaña Observatory (Tenerife, Spain), in Hannover (Germany) and in Santiago (Chile), were used for further comparisons.224576
Biogeoquímica2016Cornejo D’Ottone, M., Bravo, L., Ramos, M., Pizarro, O., Karstensen, J., Gallegos, M., … Karp-Boss, L. Biogeochemical characteristics of a long-lived anticyclonic eddy in the eastern South Pacific OceanBiogeosciences10.5194/bg-13-2971-2016 eddies are important, frequent, and persistent features of the circulation in the eastern South Pacific (ESP) Ocean, transporting physical, chemical and biological properties from the productive shelves to the open ocean. Some of these eddies exhibit subsurface hypoxic or suboxic conditions and may serve as important hotspots for nitrogen loss, but little is known about oxygen consumption rates and nitrogen transformation processes associated with these eddies. In the austral fall of 2011, during the Tara Oceans expedition, an intrathermocline, anticyclonic, mesoscale eddy with a suboxic (< 2 µmol kg−1 of O2), subsurface layer (200–400 m) was detected  ∼  900 km off the Chilean shore (30° S, 81° W). The core of the eddy's suboxic layer had a temperature-salinity signature characteristic of Equatorial Subsurface Water (ESSW) that at this latitude is normally restricted to an area near the coast. Measurements of nitrogen species within the eddy revealed undersaturation (below 44 %) of nitrous oxide (N2O) and nitrite accumulation (> 0.5 µM), suggesting that active denitrification occurred in this water mass. Using satellite altimetry, we were able to track the eddy back to its region of formation on the coast of central Chile (36.1° S, 74.6° W). Field studies conducted in Chilean shelf waters close to the time of eddy formation provided estimates of initial O2 and N2O concentrations of the ESSW source water in the eddy. By the time of its offshore sighting, concentrations of both O2 and N2O in the subsurface oxygen minimum zone (OMZ) of the eddy were lower than concentrations in surrounding water and “source water” on the shelf, indicating that these chemical species were consumed as the eddy moved offshore. Estimates of apparent oxygen utilization rates at the OMZ of the eddy ranged from 0.29 to 44 nmol L−1 d−1 and the rate of N2O consumption was 3.92 nmol L−1 d−1. These results show that mesoscale eddies affect open-ocean biogeochemistry in the ESP not only by transporting physical and chemical properties from the coast to the ocean interior but also during advection, local biological consumption of oxygen within an eddy further generates conditions favorable to denitrification and loss of fixed nitrogen from the system.2971-29791013
Biogeoquímica2016Díez, B., Nylander, J. A. A., Ininbergs, K., Dupont, C. L., Allen, A. E., Yooseph, S., … Bergman, B. Metagenomic Analysis of the Indian Ocean Picocyanobacterial Community: Structure, Potential Function and EvolutionPLOS ONE10.1371/journal.pone.0155757 cyanobacteria are ubiquitous photoautotrophic microbes that contribute substantially to global primary production. Picocyanobacteria such as Synechococcus and Prochlorococcus depend on chlorophyll a-binding protein complexes to capture light energy. In addition, Synechococcus has accessory pigments organized into phycobilisomes, and Prochlorococcus contains chlorophyll b . Across a surface water transect spanning the sparsely studied tropical Indian Ocean, we examined Synechococcus and Prochlorococcus occurrence, taxonomy and habitat preference in an evolutionary context. Shotgun sequencing of size fractionated microbial communities from 0.1 μm to 20 μm and subsequent phylogenetic analysis indicated that cyanobacteria account for up to 15% of annotated reads, with the genera Prochlorococcus and Synechococcus comprising 90% of the cyanobacterial reads, even in the largest size fraction (3.0–20 mm). Phylogenetic analyses of cyanobacterial light-harvesting genes (chl-binding pcb/isi A, allophycocyanin ( apc AB), phycocyanin ( cpc AB) and phycoerythin ( cpe AB)) mostly identified picocyanobacteria clades comprised of overlapping sequences obtained from Indian Ocean, Atlantic and/or Pacific Oceans samples. Habitat reconstructions coupled with phylogenetic analysis of the Indian Ocean samples suggested that large Synechococcus -like ancestors in coastal waters expanded their ecological niche towards open oligotrophic waters in the Indian Ocean through lineage diversification and associated streamlining of genomes ( e . g . loss of phycobilisomes and acquisition of Chl b ); resulting in contemporary small celled Prochlorococcus . Comparative metagenomic analysis with picocyanobacteria populations in other oceans suggests that this evolutionary scenario may be globally important.e0155757511
Modelación y Sistemas de Observación2016Escribano, J., Boucher, O., Chevallier, F., & Huneeus, N. Subregional inversion of North African dust sourcesJournal of Geophysical Research: Atmospheres10.1002/2016JD025020 emission of mineral dust aerosols in arid and semiarid regions is a complex process whose representation in atmospheric models remains crude, due to insufficient knowledge about the aerosol lifting process itself, the lack of global data on soil characteristics, and the impossibility for the models to resolve the fine-scale variability in the wind field that drives some of the dust events. As a result, there are large uncertainties in the total emission flux of mineral dust, its natural variability at various timescales, and the possible contribution from anthropogenic land use changes. This work aims for estimating dust emissions and reduces their uncertainty over the Sahara desert and the Arabian Peninsula—the largest dust source region of the globe. We use a data assimilation approach to constrain dust emission fluxes at a monthly resolution for 18 subregions. The Moderate Resolution Imaging Spectroradiometer satellite-derived aerosol optical depth is assimilated in a regional configuration of a general circulation model coupled to an aerosol model. We describe this data assimilation system and apply it for 1 year, resulting in a total mineral dust emissions flux estimate of 2900 Tg yr−1 over the Sahara desert and the Arabian Peninsula for the year 2006. The analysis field of aerosol optical depth shows an improved fit relative to independent Aerosol Robotic Network measurements as compared to the model prior field.2016JD025020
Modelación y Sistemas de Observación2016Gallardo, L., Henríquez, A., Thompson, A. M., Rondanelli, R., Carrasco, J., Orfanoz-Cheuquelaf, A., & Velásquez, P. The first twenty years (1994–2014) of ozone soundings from Rapa Nui (27°S, 109°W, 51 m a.s.l.)Tellus B10.3402/tellusb.v68.29484 (O3) soundings have been performed on Easter Island or Rapa Nui (27 °S, 109 °W, 51 m a.s.l.) since 1994 as part of the Global Atmospheric Watch Programme of the World Meteorological Organization. In this work, we analyse 260 soundings compiled over the period 1994–2014, and make the data available for the international community. We characterise O3 profiles over this remote area of the Pacific by means of statistical analyses that consider, on the one hand, a traditional climatology that describes the data in terms of seasonal cycles based on monthly averages and, on the other hand, a process-oriented analysis based on self-organising maps. Our analyses show the influence of both tropical and subtropical/mid-latitude air masses at Rapa Nui. The former occurs in summer and fall when convective conditions prevail, and the latter in late winter and spring when subsiding conditions are recurrent. The occurrence of stratospheric intrusions in late winter and spring in connection with deep troughs and the presence of the subtropical jet stream is also apparent in the data set. The tropospheric ozone column is in good agreement with the corresponding data derived from satellites but with a systematic overestimate of summer and fall values. There is evidence of an upward trend in ozone near the surface, which suggests the impact of local pollution. We look forward to an enhancement of the Rapa Nui observing site, given its location that offers a privileged position to observe climate change over the sparsely sampled and vast South Pacific Ocean.068
Dinámica del Clima2016Garreaud, R., Falvey, M., & Montecinos, A. Orographic Precipitation in Coastal Southern Chile: Mean Distribution, Temporal Variability, and Linear ContributionJournal of Hydrometeorology10.1175/JHM-D-15-0170.1 Nahuelbuta Mountains (NM) are a semielliptical massif 1300 m high in coastal southern Chile (37°–38°S) facing frontal storms that move from the Pacific. Mean precipitation between 900 and 1200 mm yr−1 is observed in the surrounding lowland, but river flow measurements suggest values ≥3000 mm yr−1 atop the mountains. To verify and characterize such marked orographic enhancement, 15 rain gauges were deployed around and over the NM. The observations were supplemented by a high-resolution WRF simulation and linear theory (LT) modeling during the winter of 2011. The estimated mean precipitation increases gradually from offshore (~1000 mm yr−1) to the north-facing foothills (2000 mm yr−1). The precipitation rapidly increases in the upslope sector to reach ~4000 mm yr−1 over the northern half of the NM elevated plateau, and decreases farther south to reach background values 20–30 km downstream of the mountains. The upstream (downstream) orographic enhancement (suppression) was relatively uniform among storms when considering event accumulations but varied substantially within each storm, with larger modifications during pre- and postfrontal stages and minor modifications during the brief but intense frontal passage. WRF results are in good agreement with observations in terms of seasonal and daily mean rainfall distributions, as well as temporal variability. Given its linear, steady-state formulation, the LT model cannot resolve rainfall variability at short (hourly) time scales, which in WRF is at least characterized by transient, mesoscale rainbands. Nonetheless, the rainbands are mobile so the accumulation field at monthly or longer time scales produced by the linear model is remarkably similar to its WRF counterpart.1185-1202417
Servicios Ecosistémicos2016Gómez-González, S., Ojeda, F., Torres-Morales, P., & Palma, J. E. Seed Pubescence and Shape Modulate Adaptive Responses to Fire CuesPLOS ONE10.1371/journal.pone.0159655 recruitment by seeds is regarded as an adaptive response in fire-prone ecosystems. Nevertheless, little is known about which heritable seed traits are functional to the main signals of fire (heat and smoke), thus having the potential to evolve. Here, we explored whether three seed traits (pubescence, dormancy and shape) and fire regime modulate seed response to fire cues(heat and smoke). As a model study system, we used Helenium aromaticum (Asteraceae), a native annual forb from the Chilean matorral, where fires are anthropogenic. We related seed trait values with fitness responses (germination and survival) after exposure to heat-shock and smoke experimental treatments on seeds from 10 H . aromaticum wild populations. We performed a phenotypic selection experiment to examine the relationship of seed traits with post-treatment fitness within a population (adaptive hypothesis). We then explored whether fire frequency in natural habitats was associated with trait expression across populations, and with germination and survival responses to experimental fire-cues. We found that populations subjected to higher fire frequency had, in average, more rounded and pubescent seeds than populations from rarely burned areas. Populations with more rounded and pubescent seeds were more resistant to 80°C heat-shock and smoke treatments.There was correlated selection on seed traits: pubescent-rounded or glabrouscent-elongated seeds had the highest probability of germinating after heat-shock treatments. Seed pubescence and shape in H . aromaticum are heritable traits that modulate adaptive responses to fire. Our results provide new insights into the process of plant adaptation to fire and highlight the relevance of human-made fires as a strong evolutionary agent in the Anthropocene.e0159655711
Modelación y Sistemas de Observación2016Huneeus, N., Basart, S., Fiedler, S., Morcrette, J.-J., Benedetti, A., Mulcahy, J., … Cvetkovic, B. Forecasting the northern African dust outbreak towards Europe in April 2011: a model intercomparisonAtmospheric Chemistry and Physics10.5194/acp-16-4967-2016 the framework of the World Meteorological Organisation's Sand and Dust Storm Warning Advisory and Assessment System, we evaluated the predictions of five state-of-the-art dust forecast models during an intense Saharan dust outbreak affecting western and northern Europe in April 2011. We assessed the capacity of the models to predict the evolution of the dust cloud with lead times of up to 72 h using observations of aerosol optical depth (AOD) from the AErosol RObotic NETwork (AERONET) and the Moderate Resolution Imaging Spectroradiometer (MODIS) and dust surface concentrations from a ground-based measurement network. In addition, the predicted vertical dust distribution was evaluated with vertical extinction profiles from the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP). To assess the diversity in forecast capability among the models, the analysis was extended to wind field (both surface and profile), synoptic conditions, emissions and deposition fluxes. Models predict the onset and evolution of the AOD for all analysed lead times. On average, differences among the models are larger than differences among lead times for each individual model. In spite of large differences in emission and deposition, the models present comparable skill for AOD. In general, models are better in predicting AOD than near-surface dust concentration over the Iberian Peninsula. Models tend to underestimate the long-range transport towards northern Europe. Our analysis suggests that this is partly due to difficulties in simulating the vertical distribution dust and horizontal wind. Differences in the size distribution and wet scavenging efficiency may also account for model diversity in long-range transport.4967-4986816
Servicios Ecosistémicos2016J. Alaniz, A., Galleguillos, M., & Perez-Quezada, J. F. Assessment of quality of input data used to classify ecosystems according to the IUCN Red List methodology: The case of the central Chile hotspotBiological Conservation10.1016/j.biocon.2016.10.038 the last decade, the IUCN has developed criteria analogous to the Red List of Threatened Species to perform similar risk assessment on ecosystems, creating the Red List of Ecosystems methodology. One of the most significant challenges for the construction of these lists is the gathering and availability of the information needed to apply the criteria. We present a complement to the IUCN's methodology to assess the threat level to ecosystems, estimating the spatial and temporal quality of the information available in scientific publications. We did this by applying the IUCN criteria to determine the threat level to the sclerophyll ecosystems of central Chile. Spatially explicit studies that identify disturbances in the structure of the vegetation were selected, making it possible to quantify effectively the reduction in the ecosystems' distribution. The spatial and temporal quality of the assessment were estimated as the percentage of the potential ecosystem distribution and the time frame recommended by the IUCN (50 years), that the studies represented for each ecosystem. The application of the methodology allowed the assessment of a high percentage of the ecosystems (85%), which were classified based on the studies with ranges of temporal quality from 30 to 100% and spatial quality from 12 to 100%. If only the assessments with more than medium spatio-temporal quality are considered (> 50%), eight of the 17 evaluated ecosystems are classified in threat categories, which represents 22.9% of the study area.378-385204, Part B
Dinámica del Clima2016Jiménez-Muñoz, J. C., Mattar, C., Barichivich, J., Santamaría-Artigas, A., Takahashi, K., Malhi, Y., … Schrier, G. van der. Record-breaking warming and extreme drought in the Amazon rainforest during the course of El Niño 2015–2016Scientific Reports10.1038/srep33130 El Niño-Southern Oscillation (ENSO) is the main driver of interannual climate extremes in Amazonia and other tropical regions. The current 2015/2016 EN event was expected to be as strong as the EN of the century in 1997/98, with extreme heat and drought over most of Amazonian rainforests.331306
Servicios Ecosistémicos2016Jones, J., Almeida, A., Cisneros, F., Iroumé, A., Jobbágy, E., Lara, A., … Villegas, J. C. Forests and water in South AmericaHydrological Processes10.1002/hyp.11035 America is experiencing rapid change in forest cover, of both native and planted forest. Forest cover loss is primarily attributable to fire, logging, and conversion of native forest to agriculture, pasture, and forest plantations, and types of change vary within and among the many diverse types of forests in South America. Major changes in forest cover and growing policy concerns underscore an urgent need for research on sustainable forest management and water ecosystem services in South America. Differences in land ownership and management objectives create trade-offs between wood production and water ecosystem services from forests. Work is needed to quantify how forest change and management affect ecosystem services, such as wood production versus water provision. Current scientific understanding of forest management effects on water ecosystem services in South America has important limitations, including a scarcity of long-term records and few long-term integrated watershed studies. Industry, government, universities, and local communities should collaborate on integrated applied studies of forests and water. Data archiving and publically available data are required. The creation of national networks and a multi-country South America network to identify and implement common water research protocols, share results, and explore their implications would promote common and well-supported policies. Hydrologists working in South America are well placed to tackle the challenges and opportunities for collaborative research that will maintain the intrinsic values and water ecosystem services provided by South America's forests.n/a-n/a
Dimensión Humana2016Laterra, P., Barral, P., Carmona, A., & Nahuelhual, L. Focusing Conservation Efforts on Ecosystem Service Supply May Increase Vulnerability of Socio-Ecological SystemsPLOS ONE10.1371/journal.pone.0155019 concern about the loss of ecosystem services (ES) promotes their spatial representation as a key tool for the internalization of the ES framework into land use policies. Paradoxically, mapping approaches meant to inform policy decisions focus on the magnitude and spatial distribution of the biophysical supply of ES, largely ignoring the social mechanisms by which these services influence human wellbeing. If social mechanisms affecting ES demand, enhancing it or reducing it, are taken more into account, then policies are more effective. By developing and applying a new mapping routine to two distinct socio-ecological systems, we show a strong spatial uncoupling between ES supply and socio-ecological vulnerability to the loss of ES, under scenarios of land use and cover change. Public policies based on ES supply might not only fail at detecting priority conservation areas for the wellbeing of human societies, but may also increase their vulnerability by neglecting areas of currently low, but highly valued ES supply.e0155019511
Dinámica del Clima2016Lima, M., Christie, D. A., Santoro, M. C., & Latorre, C. Coupled Socio-Environmental Changes Triggered Indigenous Aymara Depopulation of the Semiarid Andes of Tarapacá-Chile during the Late 19th-20th CenturiesPLOS ONE10.1371/journal.pone.0160580 and environmental changes are well known causes of demographic collapse of agrarian cultures. The collapse of human societies is a complex phenomenon where historical and cultural dimensions play a key role, and they may interact with the environmental context. However, the importance of the interaction between socio-economic and climatic factors in explaining possible breakdowns in Native American societies has been poorly explored. The aim of this study is to test the role of socio-economic causes and rainfall variability in the collapse suffered by the Aymara people of the semiarid Andean region of Tarapacá during the period 1820–1970. Our motivation is to demonstrate that simple population dynamic models can be helpful in understanding the causes and relative importance of population changes in Andean agro-pastoral societies in responses to socio-environmental variability. Simple logistic models that combine the effects of external socio-economic causes and past rainfall variability (inferred from Gross Domestic Product [GDP] and tree-rings, respectively) were quite accurate in predicting the sustained population decline of the Aymara people. Our results suggest that the depopulation in the semiarid Tarapacá province was caused by the interaction among external socio-economic pressures given by the economic growth of the lowlands and demands for labor coupled with a persistent decline in rainfall. This study constitutes an example of how applied ecological knowledge, in particular the application of the logistic equation and theories pertaining to nonlinear population dynamics and exogenous perturbations, can be used to better understand major demographic changes in human societies.e0160580811
Dinámica del Clima2016Masiokas, M. H., Christie, D. A., Le Quesne, C., Pitte, P., Ruiz, L., McPhee, J., … Barcaza, G. Reconstructing the annual mass balance of the Echaurren Norte glacier (Central Andes, 33.5° S) using local and regional hydroclimatic dataThe Cryosphere10.5194/tc-10-927-2016 the great number and variety of glaciers in southern South America, in situ glacier mass-balance records are extremely scarce and glacier–climate relationships are still poorly understood in this region. Here we use the longest (>  35 years) and most complete in situ mass-balance record, available for the Echaurren Norte glacier (ECH) in the Andes at  ∼  33.5° S, to develop a minimal glacier surface mass-balance model that relies on nearby monthly precipitation and air temperature data as forcing. This basic model is able to explain 78 % of the variance in the annual glacier mass-balance record over the 1978–2013 calibration period. An attribution assessment identified precipitation variability as the dominant forcing modulating annual mass balances at ECH, with temperature variations likely playing a secondary role. A regionally averaged series of mean annual streamflow records from both sides of the Andes between  ∼  30 and 37° S is then used to estimate, through simple linear regression, this glacier's annual mass-balance variations since 1909. The reconstruction model captures 68 % of the observed glacier mass-balance variability and shows three periods of sustained positive mass balances embedded in an overall negative trend over the past 105 years. The three periods of sustained positive mass balances (centered in the 1920s–1930s, in the 1980s and in the first decade of the 21st century) coincide with several documented glacier advances in this region. Similar trends observed in other shorter glacier mass-balance series suggest that the Echaurren Norte glacier reconstruction is representative of larger-scale conditions and could be useful for more detailed glaciological, hydrological and climatological assessments in this portion of the Andes.927-940210
Servicios Ecosistémicos2016Miranda, A., Altamirano, A., Cayuela, L., Lara, A., & González, M. E. Native forest loss in the Chilean biodiversity hotspot: revealing the evidenceRegional Environmental Change10.1007/s10113-016-1010-7 understanding of the spatial and temporal patterns in land use and land cover (LULC) change is a key issue for conservation efforts. In the Chilean hotspot, different studies have attempted to understand variations of LULC change. Nevertheless, a broader understanding of common patterns and variability of LULC over the entire range of the hotspot is lacking. We performed a complete review of the different studies reporting LULC changes and performed a joint analysis of their results using an integrated comprehensive approach. We related the variation of LULC change to latitude, time period and vascular plant richness using generalized linear models. Overall, there were nine studies, which covered 36.5 % of the study area, and reported the loss of 19 % of native forest (782,120 ha) between 1973 and 2011. The highest net forest loss was observed in the 1970–1990 period. This decreased in the 1990–2000 period and rose again in the 2000–2010 period. This result reveals a continuous forest loss in the last 40 years. Conversion of native forest to shrublands is the most important contributor to net native forest loss, accounting for 45 % of the loss. However, in the area of greatest species richness native forests are mainly converted to exotic tree plantations. Chilean forestry model has proved successful in expanding exotic tree plantation, but so far it has not been compatible with native forest conservation and restoration. It is imperative to design a new forestry policy to assure the conservation of one of the most unique biodiversity hotspots worldwide.1-13
Modelación y Sistemas de Observación2016Moisset de Espanés, P., Osses, A., & Rapaport, I. Fixed-points in random Boolean networks: The impact of parallelism in the Barabási–Albert scale-free topology caseBiosystems10.1016/j.biosystems.2016.10.003 points are fundamental states in any dynamical system. In the case of gene regulatory networks (GRNs) they correspond to stable genes profiles associated to the various cell types. We use Kauffman's approach to model GRNs with random Boolean networks (RBNs). In this paper we explore how the topology affects the distribution of the number of fixed points in randomly generated networks. We also study the size of the basins of attraction of these fixed points if we assume the α-asynchronous dynamics (where every node is updated independently with probability 0 ≤ α ≤ 1). It is well-known that asynchrony avoids the cyclic attractors into which parallel dynamics tends to fall. We observe the remarkable property that, in all our simulations, if for a given RBN with Barabási–Albert topology and α-asynchronous dynamics an initial configuration reaches a fixed point, then every configuration also reaches a fixed point. By contrast, in the parallel regime, the percentage of initial configurations reaching a fixed point (for the same networks) is dramatically smaller. We contrast the results of the simulations on Barabási–Albert networks with the classical Erdös–Rényi model of random networks. Everything indicates that Barabási–Albert networks are extremely robust. Finally, we study the mean and maximum time/work needed to reach a fixed point when starting from randomly chosen initial configurations.167-176150
Biogeoquímica2016Moreno-Pino, M., Iglesia, R. D. la, Valdivia, N., Henríquez-Castilo, C., Galán, A., Díez, B., & Trefault, N. Variation in coastal Antarctic microbial community composition at sub-mesoscale: spatial distance or environmental filtering?FEMS Microbiology Ecology10.1093/femsec/fiw088 environmental heterogeneity influences diversity of organisms at different scales. Environmental filtering suggests that local environmental conditions provide habitat-specific scenarios for niche requirements, ultimately determining the composition of local communities. In this work, we analyze the spatial variation of microbial communities across environmental gradients of sea surface temperature, salinity and photosynthetically active radiation and spatial distance in Fildes Bay, King George Island, Antarctica. We hypothesize that environmental filters are the main control of the spatial variation of these communities. Thus, strong relationships between community composition and environmental variation and weak relationships between community composition and spatial distance are expected. Combining physical characterization of the water column, cell counts by flow cytometry, small ribosomal subunit genes fingerprinting and next generation sequencing, we contrast the abundance and composition of photosynthetic eukaryotes and heterotrophic bacterial local communities at a submesoscale. Our results indicate that the strength of the environmental controls differed markedly between eukaryotes and bacterial communities. Whereas eukaryotic photosynthetic assemblages responded weakly to environmental variability, bacteria respond promptly to fine-scale environmental changes in this polar marine system.fiw088792
Dinámica del Clima; Servicios Ecosistémicos2016Munoz, A., Gonzalez-Reyes, A., Lara, A., Sauchyn, D., Christie, D. A., Urrutia-Jalabert, R., … Sheppard, P. R. Streamflow variability in the Chilean Temperate-Mediterranean climate transition (35°S-42°S) during the last four hundred years inferred from tree-ring recordsClimate Dynamics10.1007/s00382-016-3068-9 rainfall in South-Central Chile has decreased in recent decades, local communities and industries have developed an understandable concern about their threatened water supply. Reconstructing streamflows from tree-ring data has been recognized as a useful paleoclimatic tool in providing long-term perspectives on the temporal characteristics of hydroclimate systems. Multi-century long streamflow reconstructions can be compared to relatively short instrumental observations in order to analyze the frequency of low and high water availability through time. In this work, we have developed a Biobío River streamflow reconstruction to explore the long-term hydroclimate variability at the confluence of the Mediterranean-subtropical and the Temperate-humid climate zones, two regions represented by previous reconstructions of the Maule and Puelo Rivers, respectively. In a suite of analyses, the Biobío River reconstruction proves to be more similar to the Puelo River than the Maule River, despite its closer geographic proximity to the latter. This finding corroborates other studies with instrumental data that identify 37.5°S as a latitudinal confluence of two climate zones. The analyzed rivers are affected by climate forcings on interannual and interdecadal time-scales, Tropical (El Niño Southern Oscillation; ENSO) and Antarctic (Southern Annular Mode; SAM). Longer cycles found, around 80-years, are well correlated only with SAM variation, which explains most of the variance in the Biobío and Puelo rivers. This cycle also has been attributed to orbital forcing by other authors. All three rivers showed an increase in the frequency of extreme high and low flow events in the 20th century. The most extreme dry and wet years in the instrumental record (1943-2000) were not the most extreme of the past 400-years reconstructed for the three rivers (1600-2000), yet both instrumental record years did rank in the five most extreme of the streamflow reconstructions as a whole. These findings suggest a high level of natural variability in the hydro-climatic conditions of the region, where extremes characterized the 20th century. This information is particularly useful when evaluating and improving a wide variety of water management models that apply to water resources that are sensitive to agricultural and hydropower industries.
Dinámica del Clima2016Muñoz, R. C., Quintana, J., Falvey, M. J., Rutllant, J. A., & Garreaud, R. Coastal Clouds at the Eastern Margin of the Southeast Pacific: Climatology and TrendsJournal of Climate10.1175/JCLI-D-15-0757.1 climatology and recent trends of low-level coastal clouds at three sites along the northern Chilean coast (18.3°–23.4°S) are documented based upon up to 45 years of hourly observations of cloud type, coverage, and heights. Consistent with the subtropical location, cloud types are dominated by stratocumuli having greatest coverage (>7 oktas) and smaller heights (600–750 m) during the nighttime of austral winter and spring. Meridionally, nighttime cloud fraction and cloud-base heights increase from south to north. Long-term trends in mean cloud cover are observed at all sites albeit with a seasonal modulation, with increasing (decreasing) coverage in the spring (fall). Consistent trend patterns are also observed in independent sunshine hour measurements at the same sites. Cloud heights show negative trends of about 100 m decade−1 (1995–2010), although the onset time of this tendency differs between sites. The positive cloud fraction trends during the cloudy season reported here disagree with previous studies, with discrepancies attributed to differences in datasets used or to methodological differences in data analysis. The cloud-base height tendency, together with a less rapid lowering of the subsidence inversion base height, suggests a deepening of the coastal cloud layer. While consistent with the tendency toward greater low-level cloud cover and the known cooling of the marine boundary layer in this region, these tendencies are at odds with a drying trend of the near-surface air documented here as well. Assessing whether this intriguing result is caused by physical factors or by limitations of the data demands more detailed observations, some of which are currently under way.4525-45421229
Dimensión Humana2016Nahuelhual, L., Benra Ochoa, F., Rojas, F., Díaz, G. I., & Carmona, A. Mapping social values of ecosystem services: What is behind the map?Ecology and Society10.5751/ES-08676-210324 growing interest in mapping the social value of ecosystem services (ES) is not yet methodologically aligned with what is actually being mapped. We critically examine aspects of the social value mapping process that might influence map outcomes and limit their practical use in decision making. We rely on an empirical case of participatory mapping, for a single ES (recreation opportunities), which involves diverse stakeholders such as planners, researchers, and community representatives. Value elicitation relied on an individual open-ended interview and a mapping exercise. Interpretation of the narratives and GIS calculations of proximity, centrality, and dispersion helped in exploring the factors driving participants’ answers. Narratives reveal diverse value types. Whereas planners highlighted utilitarian and aesthetic values, the answers from researchers revealed naturalistic values as well. In turn community representatives acknowledged symbolic values. When remitted to the map, these values were constrained to statements toward a much narrower set of features of the physical (e.g., volcanoes) and built landscape (e.g., roads). The results suggest that mapping, as an instrumental approach toward social valuation, may capture only a subset of relevant assigned values. This outcome is the interplay between participants’ characteristics, including their acquaintance with the territory and their ability with maps, and the mapping procedure itself, including the proxies used to represent the ES and the value typology chosen, the elicitation question, the cartographic features displayed on the base map, and the spatial scale.321
Dinámica del Clima2016Parada, C., Frusher, S., Bustamante, R. H., Di Lorenzo, E., Bernal, P., Garreaud, R., … Yannicelli, B. South Pacific Integrated Ecosystem Studies meeting: toward conservation and sustainable use of marine resources in the South PacificFisheries Oceanography10.1111/fog.12148 South Pacific region represents the world's largest oceanic water mass and plays a significant role in the earth's climate systems. This region also contains the largest group of island nations, most of whom are dependent on marine resources for their livelihoods. Several of the largest coastal and oceanic gisheries also occur in this region (FAO, 2014). In addition, for the countries associated with the southern Pacific Ocean region, the sea provides significant social, cultural and economic benefits, with many countries being heavily reliant on both coastal and oceanic marine resources (Bell et al., 2013). Increasing coastal populations and climate change are expected to augment human demands on already fully exploited or over-exploited marine resources, threatening both food security and sustainable livelihoods (Bell et al. 2011). Therefore, its imperative that the science that describes and predicts linked biophysical and human systems is understood and developed to meet these needs. Climate change will have many impacts on marine ecosystems, with implications for end users including individuals, local communities, industries and governments. Improved scientific support for policy and management decision-making in the face of these potential impacts is essential.1-425
Servicios Ecosistémicos2016Perez-Quezada, J. F., Brito, C. E., Cabezas, J., Galleguillos, M., Fuentes, J. P., Bown, H. E., & Franck, N. How many measurements are needed to estimate accurate daily and annual soil respiration fluxes? Analysis using data from a temperate rainforestBiogeosciences10.5194/bg-13-6599-2016 accurate estimations of daily and annual Rs fluxes is key for understanding the carbon cycle process and projecting effects of climate change. In this study we used high-frequency sampling (24 measurements per day) of Rs in a temperate rainforest during 1 year, with the objective of answering the questions of when and how often measurements should be made to obtain accurate estimations of daily and annual Rs. We randomly selected data to simulate samplings of 1, 2, 4 or 6 measurements per day (distributed either during the whole day or only during daytime), combined with 4, 6, 12, 26 or 52 measurements per year. Based on the comparison of partial-data series with the full-data series, we estimated the performance of different partial sampling strategies based on bias, precision and accuracy. In the case of annual Rs estimation, we compared the performance of interpolation vs. using non-linear modelling based on soil temperature. The results show that, under our study conditions, sampling twice a day was enough to accurately estimate daily Rs (RMSE  <  10 % of average daily flux), even if both measurements were done during daytime. The highest reduction in RMSE for the estimation of annual Rs was achieved when increasing from four to six measurements per year, but reductions were still relevant when further increasing the frequency of sampling. We found that increasing the number of field campaigns was more effective than increasing the number of measurements per day, provided a minimum of two measurements per day was used. Including night-time measurements significantly reduced the bias and was relevant in reducing the number of field campaigns when a lower level of acceptable error (RMSE  <  5 %) was established. Using non-linear modelling instead of linear interpolation did improve the estimation of annual Rs, but not as expected. In conclusion, given that most of the studies of Rs use manual sampling techniques and apply only one measurement per day, we suggest performing an intensive sampling at the beginning of the study to determine minimum daily and annual frequencies of sampling.6599-66092413
Modelación y Sistemas de Observación2016Rojas, M., Arias, P. A., Flores-Aqueveque, V., Seth, A., & Vuille, M. The South American monsoon variability over the last millennium in climate modelsClim. Past10.5194/cp-12-1681-2016 this paper we assess South American monsoon system (SAMS) variability in the last millennium as depicted by global coupled climate model simulations. High-resolution proxy records for the South American monsoon over this period show a coherent regional picture of a weak monsoon during the Medieval Climate Anomaly and a stronger monsoon during the Little Ice Age (LIA). Due to the small external forcing during the past 1000 years, model simulations do not show very strong temperature anomalies over these two specific periods, which in turn do not translate into clear precipitation anomalies, in contrast with the rainfall reconstructions in South America. Therefore, we used an ad hoc definition of these two periods for each model simulation in order to account for model-specific signals. Thereby, several coherent large-scale atmospheric circulation anomalies are identified. The models feature a stronger monsoon during the LIA associated with (i) an enhancement of the rising motion in the SAMS domain in austral summer; (ii) a stronger monsoon-related upper-tropospheric anticyclone; (iii) activation of the South American dipole, which results in a poleward shift of the South Atlantic Convergence Zone; and (iv) a weaker upper-level subtropical jet over South America. The diagnosed changes provide important insights into the mechanisms of these climate anomalies over South America during the past millennium.1681-1691812
Biogeoquímica2016Ronge, T. A., Tiedemann, R., Lamy, F., Köhler, P., Alloway, B. V., De Pol-Holz, R., … Wacker, L. Radiocarbon constraints on the extent and evolution of the South Pacific glacial carbon poolNature Communications10.1038/ncomms11487 the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (Δ14C) suggest the release of 14C-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this 14C-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores retrieved along a South Pacific transect to reconstruct the spatio-temporal evolution of Δ14C over the last 30,000 years. In ~2,500–3,600 m water depth, we find 14C-depleted deep waters with a maximum glacial offset to atmospheric 14C (ΔΔ14C=−1,000‰). Using a box model, we test the hypothesis that these low values might have been caused by an interaction of aging and hydrothermal CO2 influx. We observe a rejuvenation of circumpolar deep waters synchronous and potentially contributing to the initial deglacial rise in atmospheric CO2. These findings constrain parts of the glacial carbon pool to the deep South Pacific.114877
Biogeoquímica2016Santoro, C. M., Capriles, J. M., Gayo, E. M., de Porras, M. E., Maldonado, A., Standen, V. G., … Marquet, P. A. Continuities and discontinuities in the socio-environmental systems of the Atacama Desert during the last 13,000 yearsJournal of Anthropological Archaeology10.1016/j.jaa.2016.08.006 how human societies interacted with environmental changes is a major goal of archaeology and other socio-natural sciences. In this paper, we assess the human-environment interactions in the Pampa del Tamarugal (PDT) basin of the Atacama Desert over the last 13,000 years. By relying on a socio-environmental model that integrates ecosystem services with adaptive strategies, we review past climate changes, shifting environmental conditions, and the continuities and discontinuities in the nature and intensity of the human occupation of the PDT. As a result we highlight the importance of certain key resources such as water, an essential factor in the long-term trajectory of eco-historical change. Without water the outcome of human societies becomes hazardous.
Biogeoquímica2016Schefuß, E., Eglinton, T. I., Spencer-Jones, C. L., Rullkötter, J., De Pol-Holz, R., Talbot, H. M., … Schneider, R. R. Hydrologic control of carbon cycling and aged carbon discharge in the Congo River basinNature Geoscience10.1038/ngeo2778 age of organic material discharged by rivers provides information about its sources and carbon cycling processes within watersheds. Although elevated ages in fluvially transported organic matter are usually explained by erosion of soils and sedimentary deposits, it is commonly assumed that mainly young organic material is discharged from flat tropical watersheds due to their extensive plant cover and rapid carbon turnover. Here we present compound-specific radiocarbon data of terrigenous organic fractions from a sedimentary archive offshore the Congo River, in conjunction with molecular markers for methane-producing land cover reflecting wetland extent. We find that the Congo River has been discharging aged organic matter for several thousand years, with apparently increasing ages from the mid- to the Late Holocene. This suggests that aged organic matter in modern samples is concealed by radiocarbon from atmospheric nuclear weapons testing. By comparison to indicators for past rainfall changes we detect a systematic control of organic matter sequestration and release by continental hydrology, mediating temporary carbon storage in wetlands. As aridification also leads to exposure and rapid remineralization of large amounts of previously stored labile organic matter, we infer that this process may cause a profound direct climate feedback that is at present underestimated in carbon cycle assessments.687-69099
Biogeoquímica2016Shaffer, G., Huber, M., Rondanelli, R., & Pepke Pedersen, J. O. Deep time evidence for climate sensitivity increase with warmingGeophysical Research Letters10.1002/2016GL069243 global warming from anthropogenic greenhouse gas emissions will depend on climate feedbacks, the effect of which is expressed by climate sensitivity, the warming for a doubling of atmospheric CO2 content. It is not clear how feedbacks, sensitivity, and temperature will evolve in our warming world, but past warming events may provide insight. Here we employ paleoreconstructions and new climate-carbon model simulations in a novel framework to explore a wide scenario range for the Paleocene-Eocene Thermal Maximum (PETM) carbon release and global warming event 55.8 Ma ago, a possible future warming analogue. We obtain constrained estimates of CO2 and climate sensitivity before and during the PETM and of the PETM carbon input amount and nature. Sensitivity increased from 3.3–5.6 to 3.7–6.5 K (Kelvin) into the PETM. When taken together with Last Glacial Maximum and modern estimates, this result indicates climate sensitivity increase with global warming.2016GL0692431243
Biogeoquímica; Dinámica del Clima2016Stern, C. R., Moreno, P. I., Henríquez, W. I., Villa-Martínez, R., Sagredo, E., Aravena, J. C., & De Pol-Holz, R. Holocene tephrochronology around Cochrane (∼ 47 S), southern ChileAndean Geology10.5027/andgeoV43n1-a01 Holocene tephras encountered in outcrops, cores and trenches in bogs, and lake cores in the area around Cochrane, southern Chile, are identified (based on their age, tephra glass color and morphology, mineralogy, and both bulk and glass chemistry) as H1 derived from Hudson volcano, and MEN1 derived from Mentolat volcano. New AMS radiocarbon ages indicate systematic differences between those determined in lake cores (MEN1=7,689 and H1=8,440 cal yrs BP) and surface deposits (MEN1=7,471 and H1=7,891 cal yrs BP), with the lake cores being somewhat older. H1 tephra layers range from 8 to 18 cm thick, suggesting that both the area of the 10 cm isopach and the volume of this eruption were larger than previously suggested, but not greatly, and that the direction of maximum dispersion was more to the south. MEN1 tephra layers range from 1-4 cm in thickness, indicating that this was probably a reasonably large (>5 km 3 ) eruption. Some of the lake cores also contain thin layers (<2 cm) of late Holocene H2 tephra and the recent H3 (1991 AD) tephra, both derived from the Hudson volcano. No tephra evidence has been observed for any late Pleistocene tephra, nor for the existence of the supposed Arenales volcano, proposed to be located west of Cochrane.1-19143
Modelación y Sistemas de Observación2016Van den Hoof, C., & Lambert, F. Mitigation of Drought Negative Effect on Ecosystem Productivity by Vegetation MixingJournal of Geophysical Research: Biogeosciences10.1002/2016JG003625 diversity and interaction is thought to have a beneficial effect on ecosystem functioning, particularly improving ecosystem resistance to drought. This is of significant importance in the context of a warmer world, as extreme events such as droughts become more likely. Most of the studies performed so far on vegetation interaction are based on observations. Here we use the land surface model JULES to study the potential of vegetation mixing to mitigate the negative effect of drought events on the land surface through interaction, a mechanism which is difficult to study in situ at large scales. Using a set of simulations with mixed and unmixed vegetation, we show that the carbon, water, and energy fluxes are significantly affected by vegetation competition for water resources. The interaction is in general beneficial for the ecosystem carbon assimilation due to a better use of water resources. This benefit is highest when traits between vegetation types concerning resource competition overlap least. For a tree-grass combination, mixing improves carbon assimilation by 5% to 8% during summer. The NPP benefit of mixing increases further under progressively more resource-limited conditions up to an inflection point with a benefit of 14%, after which it falls back to zero under extremely dry conditions. Mixing also tends to reduce the inter-annual variability of the ecosystem carbon sink and therefore improves the resistance of the ecosystem. Our results highlight the importance of vegetation interaction in climate simulations and impact studies, and the potential of vegetation mixing as a mitigation tool.2016JG003625
Biogeoquímica2016Verdugo, J., Damm, E., Snoeijs, P., Díez, B., & Farías, L. Climate relevant trace gases (N2O and CH4) in the Eurasian Basin (Arctic Ocean)Deep Sea Research Part I: Oceanographic Research Papers10.1016/j.dsr.2016.08.016 concentration of greenhouse gases, including nitrous oxide (N2O), methane (CH4), and compounds such as total dimethylsulfoniopropionate (DMSPt), along with other oceanographic variables were measured in the ice-covered Arctic Ocean within the Eurasian Basin (EAB). The EAB is affected by the perennial ice-pack and has seasonal microalgal blooms, which in turn may stimulate microbes involved in trace gas cycling. Data collection was carried out on board the LOMROG III cruise during the boreal summer of 2012. Water samples were collected from the surface to the bottom layer (reaching 4300 m depth) along a South-North transect (SNT), from 82.19°N, 8.75°E to 89.26°N, 58.84°W, crossing the EAB through the Nansen and Amundsen Basins. The Polar Mixed Layer and halocline waters along the SNT showed a heterogeneous distribution of N2O, CH4 and DMSPt, fluctuating between 42-111 and 27–649% saturation for N2O and CH4, respectively; and from 3.5 to 58.9 nmol L−1 for DMSPt. Spatial patterns revealed that while CH4 and DMSPt peaked in the Nansen Basin, N2O was higher in the Amundsen Basin. In the Atlantic Intermediate Water and Arctic Deep Water N2O and CH4 distributions were also heterogeneous with saturations between 52% and 106% and 28% and 340%, respectively. Remarkably, the Amundsen Basin contained less CH4 than the Nansen Basin and while both basins were mostly under-saturated in N2O. We propose that part of the CH4 and N2O may be microbiologically consumed via methanotrophy, denitrification, or even diazotrophy, as intermediate and deep waters move throughout EAB associated with the overturning water mass circulation. This study contributes to baseline information on gas distribution in a region that is increasingly subject to rapid environmental changes, and that has an important role on global ocean circulation and climate regulation.84-94117
Biogeoquímica2016Yevenes, M. A., Arumí, J. L., & Farías, L. Unravel biophysical factors on river water quality response in Chilean Central-Southern watershedsEnvironmental Monitoring and Assessment10.1007/s10661-016-5235-1 the key anthropogenic (land uses) and natural (topography and climate) biophysical drivers affecting river water quality is essential for efficient management of water resources. We tested the hypothesis that water quality can be predicted by different biophysical factors. Multivariate statistics based on a geographical information system (GIS) were used to explore the influence of factors (i.e., precipitation, topography, and land uses) on water quality (i.e., nitrate (NO 3 − ), phosphate (PO 4 3 − ), silicate (Si(OH)4), dissolved oxygen (DO), suspended solids (TSS), biological oxygen demand (DO), temperature (T), conductivity (EC), and pH) for two consecutive years in the Itata and Biobío river watersheds, Central Chile (36° 00′ and 38° 30′). The results showed that (NO 3 − ), (PO 4 3 − ), Si(OH)4, TSS, EC, and DO were higher during rainy season (austral fall, winter, and spring), whereas BOD and temperature were higher during dry season. The spatial variation of these parameters in both watersheds was related to land use, topography (e.g., soil moisture, soil hydrological group, and erodability), and precipitation. Soil hydrological group and soil moisture were the strongest explanatory predictors for PO 4 3 − , Si(OH)4 and EC in the river, followed by land use such as agriculture for NO 3 − and DO and silviculture for TSS and Si(OH)4. High-resolution water leaching and runoff maps allowed us to identify agriculture areas with major probability of water leaching and higher probability of runoff in silviculture areas. Moreover, redundancy analysis (RDA) revealed that land uses (agriculture and silviculture) explained in 60 % the river water quality variation. Our finding highlights the vulnerability of Chilean river waters to different biophysical drivers, rather than climate conditions alone, which is amplified by human-induced degradation.5188
Biogeoquímica2016Yevenes, M. A., Bello, E., Sanhueza-Guevara, S., & Farías, L. Spatial Distribution of Nitrous Oxide (N2O) in the Reloncaví Estuary–Sound and Adjacent Sea (41°–43° S), Chilean PatagoniaEstuaries and Coasts10.1007/s12237-016-0184-z and estuaries exchange large amounts of solutes, gases, and particulates between fluvial and marine systems. These exchanges and their relative distributions of compounds/particles are partially controlled by stratification and water circulation. The spatial and vertical distributions of N2O, an important greenhouse gas, along with other oceanographic variables, are analyzed from the Reloncaví estuary (RE) (~41° 30′ S) to the gulf of Corcovado in the interior sea of Chiloé (43° 45′ S) during the austral winter. Freshwater runoff into the estuary regulated salinity and stratification of the water column, clearly demarking the surface (<5 m depth) and subsurface layer (>5 m depth) and also separating estuarine and marine influenced areas. N2O levels varied between 8.3 and 21 nM (corresponding to 80 and 170 % saturation, respectively), being significantly lower (11.8 ± 1.70) at the surface than in subsurface waters in the Reloncaví estuary (14.5 ± 1.73). Low salinity and NO3 −, NO2 −, and PO4 3− levels, as well as high Si(OH)4 values were associated with low surface N2O levels. Remarkably, an accumulation of N2O was observed in the subsurface waters of the Reloncaví sound, associated with a relatively high consumption of O2. The sound is exposed to increasing anthropogenic impacts from aquaculture and urban discharge, occurring simultaneously with an internal recirculation, which leads to potential signals of early eutrophication. In contrast, within the interior sea of Chiloé (ISC), most of water column was quasi homohaline and occupied by modified subantarctic water (MSAAW), which was relatively rich in N2O (12.6 ± 2.36 nM) and NO3 − (18.3 ± 1.63 μM). The relationship between salinity, nutrients, and N2O revealed that water from the open ocean, entering into ISC (the Gulf of Corcovado) through the Guafo mouth, was the main source of N2O (up to 21 nM), as it gradually mixed with estuarine water. In addition, significant relationships between N2O excess vs. AOU and N2O excess vs. NO3 − suggest that part of N2O is also produced by nitrification. Our results show that the estuarine and marine waters can act as light source or sink of N2O to the atmosphere (air–sea N2O fluxes ranged from −1.57 to 5.75 μmol m−2 day−1), respectively; influxes seem to be associated to brackish water depleted in N2O that also caused a strong stratification, creating a barrier to gas exchange.
Biogeoquímica2016Yevenes, M. A., Soetaert, K., & Mannaerts, C. M. Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South PortugalWater10.3390/w8090385 identification of nitrate-nitrogen (NO3–N) origin is important in the control of surface and ground water quality. These are the main sources of available drinking water. Stable isotopes (15N and 18O) for NO3–N and along with a 1-D reactive transport model were used to study the origin and processes that lead to nitrogen transformation and loss in a major stream that flows into a reservoir within an intensively cultivated catchment area (352 km2) in Alentejo-Portugal. Seasonal water samples (October–November 2008, March 2009 and September 2009) of stream surface water, wells and sediment pore water were collected. The results showed consistently increasing isotope values and decreasing NO3–N concentrations downstream. During winter (wet period, November 2008 and March 2009) slightly higher NO3–N concentrations were found in comparison to early fall (dry period: October 2008) and summer (dry period: September 2009). Isotopic composition of 15N and 18O values in surface water samples from the stream and wells indicated that the dominant NO3–N sources were derived mainly from the soil and fertilizers. There was also significant nitrification in surface water at the head of the stream. Sediment pore waters showed high NO3–N values near the sediment-water interface (reaching 25 mg·N·L−1) and NO3–N concentrations sharply decreasing with sediment depth, suggesting significant NO3–N consumption. Denitrification was also detected using the 15N signature in upstream waters, but not downstream where very low NO3–N levels were measured. In the stream, the calculated isotopic enrichment factor for NO3–N was −2.9‰ for 15N and −1.78 for 18O, this indicates that denitrification accounts for 7.8% to 48% of nitrate removal.38598
Servicios Ecosistémicos2016Zhao, Y., Feng, D., Yu, L., Wang, X., Chen, Y., Galleguillos, M., … Gong, P. Detailed dynamic land cover mapping of Chile: Accuracy improvement by integrating multi-temporal dataRemote Sensing of Environment10.1016/j.rse.2016.05.016 over 4300 km north to south, Chile is a special country with complicated landscapes and rich biodiversity. Accurate and timely updated land cover map of Chile in detailed classification categories is highly demanded for many applications. A conclusive land cover map integrated from multi-seasonal mapping results and a seasonal dynamic map series were produced using Landsat 8 imagery mainly acquired in 2013 and 2014, supplemented by MODIS Enhanced Vegetation Index data, high resolution imagery on Google Earth, and Shuttle Radar Topography Mission DEM data. The overall accuracy is 80% for the integrated map at level 1 and 73% for level 2 based on independent validation data. Accuracies for seasonal map series were also assessed, which is around 70% for each season, greatly improved by integrated use of seasonal information. The importance of growing season imagery was proved in our analysis. The analysis of the spatial variation of accuracies among various ecoregions indicates that the accuracy for land cover mapping decreases gradually from central Chile to both north and south. More mapping efforts for those ecoregions are needed. In addition, the training dataset includes sample points spatially distributed in the whole country, temporally distributed throughout the year, and categorically encompassing all land cover types. This training dataset constitutes a universal sample set allowing us to map land cover from any Landsat 8 image acquired in Chile without additional ad hoc training sample collection.170-185183

2. Libros y Monografías

AutoresEditores Título del LibroTítulo del CapítuloPáginasEditorial/País/ CiudadAño
Moraga, P.Moraga, P. Energía, Cambio Climático y Sustentabilidad: Una Mirada desde el Derecho270 ppEditorial Thomson Reuters.2013
Moraga, P. Energía, Cambio Climático y Sustentabilidad: Una Mirada desde el DerechoEnergía, desarrollo sustentable y derecho internacional.255-266
Editorial Thomson Reuters.2013
Villarroel, S.
Energía, Cambio Climático y Sustentabilidad: Una Mirada desde el DerechoGestión estratégica de stakeholders en un proyecto de energías renovables no convencionales: Lecciones del caso del proyecto eólico Chiloé.125-150Editorial Thomson Reuters.2013
Donoso, C., González, M.E., Lara, A. (eds). Ecología Forestal: Bases para un Manejo
sustentable de los Bosques Nativos.
610 p.Marisa Cuneo Editores. Valdivia. 2013
Lara, A., Laterra, P., Manson, R., and Barrantes, G.Servicios Ecosistémicos hídricos: estudios de caso en América Latina y el Caribe. Valdivia, Chile.
312 p.Red ProAgua CYTED. Imprenta América. 2013
Aldunce, P., Levín, V and León, A.L. Sygna;
K. O'Brien; J. Wolf(Eds)
A Changing Environment for
Human Security: Transformative Approaches to Research, Policy and Action
A.Disaster risk reduction informing climate change
adaptation: Social Capital in Aguita de la Perdiz, n. 29
336-346 E. Routledge, Taylor and Francis Group2013
Cárcamo M., A. Lara, L. Palma, M. Lavado, D. Roco, R. BravoLara A., P Laterra, R Manson, G Barrantes (eds.)Servicios ecosistémicos hídricos: estudios de caso en
América Latina y el Caribe
Proyecto Innova Cuencas
APR; Una oportunidad para generar condiciones habilitantes para el desarrollo de
comunidades rurales: Hacia la construcción de un modelo de gestión de cuencas en la
región de Los Ríos, Chile
169-185Red ProAgua CYTED. Valdivia, Chile. Imprenta América.2013
Lara A, Little C, Cortés M, Cruz E, González M, Echeverría C, Suarez J, Bahamondez A,
Coopman R
Donoso, C., M. González, A.
Lara, (eds.)
Ecología Forestal:
Bases para un manejo sustentable de los Bosques Nativos
Restauración de ecosistemas forestalesMarisa Cuneo Editores. Valdivia.2013
Lara A., C. Little, M.E. González, D. LobosLara A., P Laterra, R Manson,
G Barrantes.
Servicios ecosistémicos
hídricos: estudios de caso en América Latina y el Caribe.
Restauración de bosques nativos para
aumentar la provisión de agua como un servicio ecosistémico en el centro-sur de Chile:
desde las pequeñas cuencas a la escala de paisaje
57-78Red ProAgua CYTED. Valdivia, Chile. Imprenta
Red ProAgua CYTED. Valdivia, Chile. Imprenta
Donoso, C., González, M., Lara, A. (eds.) Ecología Forestal: Bases para un manejo sustentable de los
Bosques Nativos
Sucesión y Dinámica de Bosques
Templados en Chile.
Marisa Cuneo Editores.
Little C., A. Lara. Donoso, C., M. González, A. Lara (eds.)Servicios ecosistémicos de los bosques nativos del centro sur de
Ecología Forestal: Bases para un manejo sustentable de los
Bosques Nativos
Marisa Cuneo Editores. Valdivia2013
Little, C, A. Lara, M.E. González.A. Clewell and J. Aronson (eds) Ecological Restoration: Principles, Values, and Structure of an Emerging
Temperate Rainforest Restoration in Chile190-196Society of Ecological Restoration,
2nd Edition, Island Press, San Diego, USA.
Masson-Delmotte, V., M. Schulz, M. Rojas,y otrosStocker, T. F., D. Qin, y otros Climate Change 2013: The Physical Science Basis. Contribution of
Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on
Climate Change
Information from Paleoclimate
Cambridge, United Kingdom and New York, NY, USA2013
Stocker, T. F., D. Qin, M. Rojas, y otrosStocker, T. F., D. Qin, y
Climate Change 2013:
The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment
Report of the Intergovernmental Panel on Climate Change
Technical Summary Cambridge University Press, Cambridge, United Kingdom and New York, NY,

4. Boletín Jurídico 2014

Boletín preparado por el Área Jurídica de Dimensión Humana del (CR)2, mensualmente y con miras a la Conferencia de las Partes de la Convención Marco de Naciones Unidas sobre Cambio Climático, COP 21, que se desarrolló en Perú durante el año 2014.

5. Boletín Jurídico 2015

Boletín preparado por el Área Jurídica de Dimensión Humana del Centro, mensualmente y con miras a la Conferencia de las Partes de la Convención Marco de Naciones Unidas sobre Cambio Climático, COP 21, que se desarrollará en Francia durante el presente año.

Número 9, abril de 2015 | “Herramientas del derecho internacional hacia la COP 21”

6. Tesis Concluídas

  • “Intercambio de gases invernadero hacia la atmósfera versus acumulación de carbono y nitrógeno en los sedimentos del estuario/humedal Tubul-Raqui”, alumno Inger Daniel, dirigida por Laura Farías (Universidad de Concepción)
  • “Cambios multicenteniales en el crecimiento de bosques de Nothofagus dombeyi en los Andes valdivianos” alumna Paulina Montory, dirigida por Duncan Christie (Universidad Austral)
  • “Estudio de la interacción entre agua superficial y subterránea en la cuenca del río San José” alumno Carlos Ardissoni, dirigida Paulo Herrera   (Universidad de Chile)
  • “Influencias de la discusión sobre Equidad en el Acceso al Desarrollo Sostenible en conceptos y principios del derecho ambiental internacional: Nuestro presente común” alumno Miguel Pelayo, dirigida por Pilar Moraga (Universidad de Chile)
  • “Modelación de Flujos en geometría compleja (Rajos Mineros)” alumno Federico Flores, dirigida por René Garreaud (Universidad de Chile)
  • “Patrones multicenteniales de crecimiento de Nothofagus pumilio a traves de un gradiente altitudinal en los Andes valdivianos” alumno Gonzalo Duarte, dirigida por Duncan Christie (Universidad Austral)