woman holds up a petri dish with visible microbes present
Illinois-Indiana Sea Grant funded Maureen Coleman at the University of Chicago to identify microbes throughout the Great Lakes. (Illinois-Indiana Sea Grant Photo/Irene Miles)

Life on Earth is dependent on microbes to create the air we breathe and transform nutrients. This is of course true for Great Lakes ecosystems, but previously, no comprehensive research has looked at what microbial populations are in these waters.

Now, University of Chicago researchers are the first to systematically identify the species and abundance of viruses, bacteria and other microscopic life in all five Laurentian Great Lakes.

Maureen Coleman and members of her lab have been collecting samples aboard Great Lakes research vessels since 2012. In 2015, Illinois-Indiana Sea Grant began supporting their work to build a baseline understanding of microbial communities. Now, the team, which includes Sara Paver, Justin Podowski and María Hernández-Limón, have been awarded a grant from the National Science Foundation to continue their studies.

“The primary pattern we found is that microbes differ with depth,” said Coleman. “When the lakes are stratified in the summer, the surface heats up and the bottom stays cool. At that point, we see very different communities in the surface and the deep water. It’s driven by temperature and light, probably.”

The microbial communities on the surface are different in the upper lakes—Superior, Michigan and Huron—than the lower lakes—Erie and Ontario. “This makes sense because the upper and lower Great Lakes diverge physically and chemically,” said Coleman.  “In addition to temperature, nitrogen, phosphorus and chlorophyll levels are different between the upper and lower lakes. The microbes respond to that.”

Tony Briscoe, environmental reporter with the Chicago Tribune, has more of the story: “Minuscule microbes wield enormous power over the Great Lakes. But many species remain a mystery.”

 

Writer: Irene Miles, 217.333.8055, miles@illinois.edu

IISG Instagram

📢 Show Your Support for Sea Grant! 📢Continued federal funding for Sea Grant in FY26 is crucial, and we need your help to demonstrate the nationwide support for these essential programs.🖊️ Sign the letter urging Congress to continue funding Illinois-Indiana Sea Grant and all 34 state Sea Grant programs:🔗 https://forms.gle/7sPGHGyh8j8a7vfGA or link in bio
Exciting news! The call for sessions for the 2026 Emerging Contaminants in the Environment Conference has been extended! We are excited to offer the opportunity to propose a speaker or panel session during the 2026 Emerging Contaminants in the Environment Conference April 28-29.  The conference will feature traditional 15-minute presentations and a poster session on the latest in emerging contaminant research, policies, and outreach in the soil, water, and air.The deadline to propose a session is September 30, 2025.Learn more at go.illinois.edu/ecec or the link in bio
Stay safe and have fun this Fourth of July with these 5 water safety tips! Click the link in bio to learn more ways to keep yourself and others safe as you enjoy the Lake Michigan beaches this holiday.
Four science educators from Illinois and Indiana have been selected for the 2025 Shipboard Science Immersion on Lake Michigan July 7-13. The educators will spend a full week alongside researchers aboard the EPA research vessel Lake Guardian. Afterwards, they will bring Great Lakes science back to their classroom. Learn more and meet the four incredible teachers representing Illinois and Indiana at the link in bio.
Skip to content