Green Scum Found on Lake Superior


For what might be the first time, pond scum has been found on the pristine waters of Lake Superior. The discovery concerns state and federal officials.

This wasn’t the thick green scum found in many inland lakes in the heat of summer, more like a light coating of pollen on the water you’d find in the spring. But about two miles of coastline from Cornucopia to the Apostle Islands sea caves area had this blue-green algae. Apostle Islands resource manager Julie Van Stappen says this could mark a warming of Lake Superior, “It potentially could be.It’s very unusual to have any kind of algae blooms in Lake Superior.”

Van Stappen says the water temperature is 67 degrees, much warmer than the usual peak of 58 degrees. The cause of the pond scum? Department of Natural Resources Lake Superior team leader Nancy Larson says it’s a combination of unusual events, including last month’s flood, “We feel it’s like a perfect storm because of the flood, putting a lot of nutrients into the lake and then the higher temperatures, the warmer temperatures we’ve been experiencing have led to this algae bloom.”

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Larson says since summer has two months to go, the green scum may return, “I hope not. But it could happen again and that’s why we’re asking people to let us know if they observe anything strange like that, like a surface scum of algae or a pea-green soup kind of coloring in the water. We’ll go out and take a look.”

The blue-green algae has since broken up. If ingested by people and wildlife, it can cause flu-like symptoms.

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