Today's Messages

Please join the Great Lakes Center and Biology Department for the seminar "Lakewide Circulation Structures Microbial Life and Rewires Ecosystem Function Across Lakes Erie and Ontario" presented by Dr. Mar Schmidt at 3:00 p.m. on Tuesday, April 28th in SAMC 176.  All are welcome.

Research Abstract:  The Great Lakes harbor 21% of the world's surface freshwater and supply drinking water to tens of millions of people. A single gallon of lake water contains more microbes than there are people on Earth, yet we lack a predictive understanding of how these invisible engines of aquatic ecosystems are structured in space and time. I present two complementary studies from the lower Great Lakes revealing that basin-scale circulation is a powerful organizer of microbial life, with profound consequences for ecosystem function and water quality. In Lake Ontario, wind-driven upwelling and Kelvin wave propagation act as recurring ecological disturbances, mobilizing rare taxa with unique biogeochemical potential and restructuring shoreline microbial communities. In Lake Erie, basin-scale gyres transport cyanobacterial "cohorts" that structure heterotrophic diversity, biomass, and metabolic activity lakewide. Critically, cyanobacterial identity, not just biomass, determines these outcomes, revealing a circulation-driven pathway connecting bloom dynamics directly to hypoxia. Together these findings reframe Great Lakes microbial ecology: physics does not just move water, it assembles microscopic ecosystems. As climate change drives the Great Lakes toward prolonged stratification and intensified upwelling seasons, these physical-biological feedbacks will increasingly determine the water quality future for tens of millions of people.