Collaborative Research: Burial of organic carbon in temperate, shallow lakes

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

There is worldwide concern over increasing concentrations of carbon dioxide in the atmosphere and its influence on global climate. Managing atmospheric concentrations of carbon dioxide requires understanding how ecosystems process carbon, and identifying systems that potentially store carbon for long periods of time. Carbon dynamics of the ocean are critical to atmospheric carbon remediation, but recent work has suggested that storage of carbon in freshwater systems is also important to the global carbon cycle. Understanding the controls of carbon storage in lake and wetland sediments represents a potential regulatory mechanism for increasing atmospheric carbon removal through management practices. This project will assess the role of shallow lakes and wetlands in the global carbon cycle and determine if they can be managed to store carbon in sediments more efficiently. Shallow lakes are dominated by either submerged aquatic plants or algae, and this study will test the hypothesis that shallow lakes dominated by submerged plants store more carbon in sediments than do lakes dominated by algae. It is hypothesized that submerged plants facilitate higher carbon storage because they are more resistant to decomposition relative to algae. These hypotheses will be tested using both modern day measurements and records from lake sediment cores to estimate carbon storage rates over scales of decades to centuries. Modern-day measurements will involve both comparative and experimental approaches, including observations on lakes that are manipulated to shift from algae to submerged-plant dominance.

Many shallow lakes and wetlands are already heavily managed, but not necessarily for carbon removal. This project will increase fundamental knowledge regarding sources and controls of carbon storage in these systems, and determine whether shallow lakes can be managed to increase uptake and storage of atmospheric carbon dioxide. Research efforts will be strongly directed at undergraduate, graduate, and post-graduate training, with results available in traditional scientific literature and on the web. In particular, scientists will coordinate with the Science Museum of Minnesota to develop a website explaining the relevance and results of this work to the general public.