Exploring Microbial Ecosystems in the Submerged Sinkholes of the Great Lakes

Dear Eos,

Colorful microbial mats composed of photosynthetic cyanobacteria (dark purple layers) and chemosynthetic microbes (white patches) thrive in the cold, oxygen-poor, sulfur-rich waters of submerged sinkholes in Lake Huron.  The carbon and oxygen cycles of these microbial ecosystems remain an enigma.  Here, we are diving to monitor and sample field experiments set up to measure the changing composition of water overlying the microbial lakescape for quantifying their photosynthetic, chemosynthetic and respiratory roles using in situ sensors and follow up analyses (photo of Joe Hoyt by Tane Casserley).  Cyanobacteria-dominated microbial mats such as this – prevailing in the shallow oxygen-less, sulfur-laden seas of the Proterozoic – may have oxygenated our planet during its youth.  We are hoping our exploration of these modern-day analogs will provide clues to the life-changing phenomena that began in the distant past.

Tony Weinke and Bopi Biddanda

Annis Water Resources Institute, Grand Valley State University

http://www.gvsu.edu/wri/

Russell Green, Joe Hoyt and Tane Casserley

NOAA Office of Marine Sanctuaries

https://sanctuaries.noaa.gov/