Watch Out for Blue-Green Algal Blooms

High temperatures can bring harmful algal blooms

Algae, microscopic aquatic plants, are a natural part of any aquatic ecosystem. Most algae are harmless, but under the right conditions certain types of algae can pose health risks. People or animals may become sick if they touch or ingest affected water. In extreme cases, dogs and other animals have died after exposure to lake water containing toxic blue-green algae.

Not all blue-green algae are toxic, and there’s no visual way to predict whether a blue-green algal bloom contains toxins and is harmful to humans or animals. But harmful blooms are sometimes said to look like pea soup, green paint, or floating mats of scum, and they often have a bad odor.

For more information, go to the MPCA’s Blue-green Algae and Harmful Algal Blooms webpage.