Collaborative Research: Arctic to the Amazon: Physical Processes Controlling Gas Exchange from Freshwater Ecosystems.

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Estimates of carbon dioxide and methane emissions indicate inland aquatic ecosystems play an important role in carbon balances across multiple scales ranging from the local ecosystem scale to regional and global scales. Given ongoing changes in biogeochemical cycles due to global warming and human activities, studies are being conducted worldwide to more accurately assess the role of lakes and reservoirs in regional and global carbon cycles and to estimate metabolic activity in lakes. Essential to these efforts are accurate estimates of gas fluxes at the air and water interface, yet current models do not include all the physical processes which mediate gas exchange. This multiscale modeling research includes field measurements of gas exchange and of processes controlling gas exchange across a range of freshwater bodies from small arctic lakes to the large floodplain lakes of the Amazon. These data will be used to develop gas exchange models for freshwater ecosystems that include not just wind speed but the full range of physical processes that enable fluxes across the interface between air and water. They will also take into account the differences in dominant processes in warm versus cold water lakes. The new models, combined with improved understanding of the underlying dynamics enabling gas exchange, will enable improved estimates of greenhouse gases fluxes from individual freshwater bodies worldwide and accurate scaling up of estimated over broad regions.Results will inform procedures at Global Lake Ecological Observatory Network sites worldwide and proposed lake sites within the National Ecological Observatory Network. Postdoctoral fellows and graduate students in the United States and abroad will receive training in micrometeorology, limnology and biogeochemistry. The principle investigators will contribute to or conduct workshops on techniques for field courses and at national meetings in the United States, Sweden and Brazil.