Isanti Soil & Water Conservation District

Blue Green Algae 

blue green algae

Blue Green Algae is a type of harmful algae bloom found in Minnesota. These blooms can be harmful to humans and pets. Although it is called algae, these blooms are actually a type of bacteria called cyanobacteria. 


These blooms often look like spilled pant or pea soup in the water. However, they are not always thick and dense. Blue Green Algae blooms can be thin and barely visible as well. They can also have a swampy odor. There are ways to test if you have a Blue Green Algae bloom. 

  1. Collect a jar of water from the surface. Let the water sit until the algae settles. If it settles to the bottom it is not blue green algae. If it floats to the top there is likely blue green algae present. More about this method can be found here along with information to perform a stick test.
  2. Test strips can be used to determine if toxic bacteria is present. These can be purchased online. 


Helpful links:

Pollution Control Agency

University of Minnesota Extension