Most freshwater systems are net carbon dioxide emitters due to the processing of terrestrial carbon. Globally this amounts to an estimated total of 1.9 Petagrams (nearly 2 billion kilograms) terrestrial carbon per year, nearly half of which is emitted. This number is of the same order of magnitude as the net ecosystem productivity of the terrestrial biosphere. Accounting for roughly 20 percent of all surface freshwater, the Laurentian Great Lakes are the largest surface freshwater system in the world and are threatened by significant regional changes in the next century due to global change. While the role of bacterio- and virioplankton communities as part of the aquatic microbial loop is well appreciated, the resolution at which these communities are incorporated into food web models is very coarse. Efforts to increase this resolution by metagenomic sequencing are rapidly increasing our insights into marine microbial life yet lag significantly behind in freshwater environments. To learn more about microbial feedback responses to global change in the Great Lakes region, this project focuses on samples from Lake Huron to learn more about how gradients such as temperature, dissolved oxygen and nutrients constrain microbial community structure and activity.
PI: Vincent Denef, University of Michigan