Hot temperatures and sunny days are great to get out on Wisconsin beaches, but it’s also a recipe for toxic lake scum.
That scum is ‘cyanobacteria’ commonly called blue-green algae. Gina LaLiberte with the DNR says the name ‘blue-green’ can be misleading, and that you should be careful with any brackish water. “People hear the word blue in blue-green algae, and they think it’s going to be blue. But active growing blue-green algae are most often green when they’re forming blooms in Wisconsin lakes.”
The algae forms any time there’s high temperatures, plenty of sunlight, and little wind. In Wisconsin blooms typically peak from July to September.
Swimming through them can cause rashes, gastrointestinal ailments and respiratory irritation. If you think you’ve been sickened, contact your doctor to get tested.