Carbon Cycling and Microbial Community Characteristics in a High-Latitude Wetland

As dynamic systems, high-latitude watersheds are particularly impacted by climate change. Because we do not fully understand how they function we cannot predict how crucial aspects of these systems will develop in the future. Globally, high-latitude wetlands will likely experience changes in microbial biodiversity and the rates of biogeochemical processes, and these changes will in turn influence carbon-bearing compounds in the system. The objective of our research is to determine the key processes associated with carbon biogeochemistry along two axes on the Copper River Delta (CRD) in Alaska: 1) a depth axis in wetland sediments, and 2) a distance axis between glaciers and the ocean. Thus far, results reveal springtime spikes of dissolved methane >250 μM in CRD ponds and rates of carbon burial as high as 390 g organic C per m² per yr. Maximum carbon burial rates were over 60x higher in pond sediments proximal to glaciers with high levels of total iron than in those distant from glaciers with lower total iron. These observations may be partly due to high sediment delivery near the glaciers. DNA has been extracted and amplified from over 40 wetland sediment samples from five different ponds, and microbiome analysis to determine diversity and functional capability is underway. These measurements bring to light the importance of understanding changing biogeochemical processes in high-latitude wetlands and the potential influence that location and iron chemistry may have on carbon cycling.