SUPERIOR, Wis. (AP) — State park officials have found pond scum on the waters of Lake Superior, a discovery that might be linked to warmer water temperatures.
A Wisconsin Public Radio report says about two miles of coastline from Cornucopia to the Apostle Islands sea caves had a light coating of blue-green algae.
Apostle Islands resource manager Julie Van Stappen says it's unusual to have any kind of algae blooms in the lake.
She says the water temperature is 67 degrees, whereas it's usually about 58 degrees. Lake Superior is experiencing some of its hottest water temperatures in the past 30 years. Some parts of the big lake are reporting 20 degrees above average as we enter August.
Meteorologist Mike Stewart said "It has been the warmest summer in 142 years of data gathering in the Duluth area.”
Nancy Larson is with the state Department of Natural Resources. She says the scum is a result of several factors, including warmer temperatures and flooding that carried nutrients into the lake.
Much of the algae has broken up, but Larson says it's possible it could return.