El (CR)2 invita a la charla de la Dra. Amy Townsend-Small, Departments of Geology and Geography, University of Cincinnati, USA, el próximo 26 de junio/ 12:00 hrs / 5to piso/ DGF (Blanco Encalada 2002. FCFM): «Using Stable Isotopes and Radiocarbon to Constrain Anthropogenic and Climate- Related C and N cycles Feedbacks»
Abstract: Human impacts have a complicated impact on global cycles of water, carbon, and nitrogen, including on interactions between these cycles. My research focuses on the use of stable isotopes and radiocarbon to explore feedbacks between global climate, urbanization, and water and element cycling. The first part of this talk will explore how climate-driven changes in precipitation and runoff affect delivery of terrestrial organic C and N to the coastal ocean. This includes examples from the Amazon headwaters and the Alaskan Arctic North Slope. The second part of the talk will explore the use of stable isotopes and radiocarbon to partition sources of the powerful greenhouse gases nitrous oxide and methane. Stable isotopes of N and O can be useful at distinguishing between microbial processes that produce nitrous oxide, and this will be illustrated with examples from fertilized soils, wastewater treatment plants, and the ocean, which are all major contributors to global N2O emissions. For methane, stable isotopes of C and H can distinguish between biogenic and thermogenic CH4, with applications in urban areas, Arctic ecosystems, and natural gas drilling regions.