Aquatic metabolism and carbon dioxide flux: Linking physical and biological processes in Amazon floodplains

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Changes in carbon dioxide in the atmosphere are influenced by the activities of wetland plants and microbes. Wetlands are a major natural source of greenhouse gases. The Amazon basin contains the largest area of tropical wetlands on Earth. Wetlands in this region consist of floating grasses, flooded forests and lakes surrounded by upland rainforests. Human activities and environmental changes are changing the landscape in the Amazon. How these changes affect wetlands is critical for understanding the global carbon cycle. The immense size and remoteness of much of the Amazon has limited this understanding. This project will take advantage of new satellite technology to map flooding and measure the extent of wetlands in the Amazon. This research will also apply new techniques to measure greenhouse gas emissions in remote locations. These new approaches will produce critical knowledge on biological activities responsible for wetland greenhouse gas emissions. The results will lead to better resource management strategies, and improved accounting of global carbon dioxide emissions. In addition, this project will provide training for postdoctoral scientists and graduate students in cutting-edge technologies for studying global carbon cycling. Inland aquatic ecosystems, including wetlands, have a large and disproportionate impact on carbon cycling and greenhouse gas emissions. Predicting how human activities and environmental changes will alter carbon cycling in tropical wetlands, such as those in the Amazon basin, requires combining intensive field measurements with remote sensing and mathematical models. The exchange of greenhouse gases, such as carbon dioxide, between wetlands and the atmosphere depends on hydrodynamic, chemical and biological processes. This research is designed to test the hypothesis that most of the carbon dioxide released to the atmosphere from Amazonian wetlands represents recycled aquatic productivity rather than lateral transport of organic matter from uplands. To test this hypothesis, the project applies state-of-the-art measurements of turbulence, fluxes of greenhouse gases, and remote sensing of flooded areas and aquatic plants. The distinction between aquatic and terrestrial sources of organic matter is critical to predicting the impacts of changes in land-use and climate on wetland greenhouse gas fluxes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.