Award: OCE-1636052

Coastal wetlands are one of the most productive ecosystems on the earth. Wetlands are increasingly recognized and valued for sequestration and storage of carbon for centuries to millennia. The top 1 meter of all soil contain almost twice the amount of carbon that is in the atmosphere and wetlands, while only about 5% of the land area, have 1/3 of all soil carbon. While focus of soil carbon is on the top meter, there can be a lot more C stored below that depth. Sea level rise is causing the erosion of coastal wetland carbon (Figure 1). Carbon, that has been stored in the wetland soil for up to 800 years under anaerobic conditions, is being release as wetlands are eroded. In some cases, there is more carbon stored at depth than at the surface (Figure 2). This erosion is caused by small wind driven waves as well as by large episodic tropical cyclone waves. Once released, this carbon is broken down by microbes and converted to mostly carbon dioxide and released into the air. This carbon release has consequences for the global carbon cycle, specifically increasing CO2 in the atmosphere. In addition to the release of carbon, there are also nutrient releases of nitrogen and phosphorus into the surface water as the organic matter breaks down. The export of carbon and nutrients to the coastal ocean can play a role in hypoxia, or the creation of low oxygen coastal water which could affect fish and benthic organisms. It is possible to slow the erosion rate by increasing mineral sediment in the coastal marsh soil as well as providing protection from the waves. The project allowed for the cross-disciplinary training of a number of graduate and undergraduate students with the overall concept of the proposal?s focus on fate of eroded coastal wetland carbon. The results have been and will continue to be presented to Dr. White's advanced undergraduate wetlands class and graduate wetland biogeochemistry class as well as shared with the citizens of Louisiana that are being affected directly by this high rate of coastal wetland loss. The techniques, methods, and the carbon characteristics and age yielded by this research will continue to be utilized for a range of research projects in the PIs laboratories. Last Modified: 02/17/2022 Submitted by: John R White