The most detailed genetic study of western Lake Erie's shifting cyanobacterial communities is yielding new insights into the factors that were at play last August when high levels of a bacterial toxin shut down the drinking water supply to more than 400,000 Toledo-area residents.

The University of Michigan-led study is revealing that as environmental conditions in the lake changed throughout summer 2014, the relative abundance of various cyanobacterial strains shifted in response, altering the bacterial bloom's toxicity.

"The big question we're trying to answer here is what environmental factors control the toxicity of these blooms, and it now appears there may be multiple factors involved, including the availability of nitrogen," said U-M marine microbiologist and oceanographer Gregory Dick, leader of the multidisciplinary project.

"The cyanobacterial communities in these blooms are changing through time, and we're able to track those changes at a level of detail that has not previously been possible."

Dick leads the team, which includes several others from EEB: Drs. Vincent Denef (co-principal investigator), Melissa Duhaime, George Kling and Tim James, as well as collaborators in the Department of Earth and Environmental Sciences (where Dick's primary appointment is), Cooperative Institute for Limnology and Ecosystems Research, U-M Water Center, and National Oceanic and Atmospheric Administration. 

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