Blue-green algae detected at 2 popular Minneapolis beaches

A potentially harmful bloom of blue-green algae at two popular Minneapolis beaches has prompted city officials to issue an alert to community members. A blue-green algae advisory is in place at Lake Nokomis' Main Beach and 50th Street Beach after microcystin was detected in this week’s water samples. That’s the chemical that blue-green algae can produce, and its levels on the Minneapolis lake exceeded the amount that state agencies recommend for safe swimming and water activities.The naturally occurring algal bloom can be toxic to both humans and animals, but there is no way to tell if it is toxic just by looking at it.Officials are now asking residents to keep children and pets out of the water while the algal bloom is present. Minnesota Pollution Control Agency The Minnesota Department of Health advises, “When in doubt, stay out!” and to avoid swimming if you can’t see your feet in knee-high water. If you think you or your pet has been swimming or wading in an algae bloom, wash them off with fresh water immediately.Blue-green algal blooms are most common in warm, calm, sunny weather when temperatures are over 75 degrees, and typically occur during summer and early fall. It typically looks like pea soup or spilled green paint on the water.The advisory comes as the Minneapolis Park and Recreation Board is also investigating a reported fish kill on Lake Nokomis, where about 150 fish were found dead Monday near the boat launch and on the western lakeshore.According to the Minnesota Department of Natural Resources, lake fish can be prone to disease in the late spring and early summer because warming water stresses out the aquatic animal's immune systems and deprives them of oxygen. Fish kills do not impact the lake's water quality for swimming or boating.The early summer water quality issues aren't limited to Minneapolis, either. Across Hennepin County, weekly water testing is now underway at public beaches to ensure they remain safe for swimming.The city of Plymouth announced Thursday that East Medicine Lake Beach will be closed until further notice due to high levels of E. coli bacteria, though another beach on the west side of the lake remains open.Weekly testing will run through Labor Day. For more information about Hennepin County swimming beach closures, click here.For up-to-date information on Minneapolis lake water quality, click here.