There have been a few reports of blue-green algae on Lake Superior over the years with a first confirmed sighting in 2012. This summer researchers from universities, state and federal agencies from around the region are undertaking a coordinated effort to intensively study and monitor Lake Superior to determine when and where blooms occur on the lake.. Read the full story by MPR News.
Great Lakes Commission
https://www.glc.org/dailynews/20210728-algae-blooms