Blue-green algae in Minnesota lakes

Understanding and predicting harmful algal blooms
layer of blue-green algae floats on top of a lake surrounded by trees

Algae blooms can turn water green and smelly, contribute to fish kills, and at times produce toxins that pose a health risk to people and animals. These types of algae blooms are referred to as Harmful Algal Blooms, or HABs, and their occurrence is on the rise in Minnesota lakes, streams and wetlands.

Algae occur naturally in almost all surface waters. They are an essential source of food for many aquatic organisms and come in many shapes and forms.

Under the right temperature and water conditions, blue-green algae (cyanobacteria) can grow very rapidly and form extremely high-density populations or "blooms." These colonies can then float to the water surface and form a dense layer of scum.

More frequent HABs may be triggered by a number of factors, including urban and agricultural runoff and climate change.

Using new lake-monitoring technology, Minnesota state agencies and scientists are creating a better picture of potential HABs in Minnesota.

Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative‐Citizen Commission on Minnesota Resources (LCCMR).