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

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.
🌿 Educators—Explore Restoration in Action! Join us Thursday, July 31 at Purdue Northwest (Hammond, IN) for a FREE full-day workshop diving into the transformation of the Grand Calumet River Area of Concern.🚍 Tour restored sites🧠 Engage with VR curriculum📚 Earn 6 PD hours🥐 Breakfast & lunch included🔗 Register now at the link in bio and bring real-world science to your classroom.Register by July 21st.
Attention STEM educators! Our new aquaponics curriculum is here! Designed for 9-12th grade classrooms with operating aquaponics systems, this curriculum, created by educators for educators, teaches STEM concepts through the lens of aquaponics, aligning with NGSS and Great Lakes Literacy Principles. Learn more at the link in bio.
Big news from Illinois‑Indiana Sea Grant! We’re thrilled to announce Dr. Stuart Carlton, our Assistant Director since 2018, will step into the Director role on July 14, 2025. Join us in congratulating Stuart, and read on at the link in bio to find out more about the transition!
Skip to content