The role of lakes in the global carbon budget has previously been underestimated. The total amount of organic matter stored in the sediments of lakes and reservoirs is estimated to exceed that stored in the sediments of the world’s oceans. Freshwater lakes can act as net sources or sinks of atmospheric carbon, and microbes mediate much of their carbon cycling. The microbial loop ensures that carbon fixed by the autotrophic phytoplankton community (algae and cyanobacteria) supports the growth of the chemotrophic bacterial community. The composition of lake microbial communities varies with trophic status, which determines how much carbon cycles through a lake and the route it takes through the ecosystem. An improved understanding of microbial controls on carbon cycling in lakes is critical for better predicting how aquatic ecosystems will respond to global climate change.
Proposer’s Name: Katherine McMahon, University of Wisconsin-Madison