Harmful Algal Blooms

Harmful algal blooms are the excessive growth of a variety of algae, and/or toxin producing algae blooms. Eutrophication, or the enrichment of water bodies in minerals and nutrients is a primary cause of these events. The large growth can have major impacts on ecosystems by blocking sunlight, stealing nutrients, and depleting oxygen. The depletion of oxygen through nightly respiration and the decomposition of dead algae can lead to oxygen levels so low that it forces organisms such as fish to leave the area or die.

Toxic algae 

Certain types of algae can produce toxins at levels that are harmful to humans, wildlife, and pets. A common concern for toxicity in our region is Cyanobacteria (or Blue Green Algae). Cyanobacteria has a variety of appearances, but the more noticeable ones can be seen as a layer of paint, foam, or scum on the water.

Resources

• To report blooms and find toxin data related to cyanobacteria blooms in Washington lakes, ponds, and streams - Washington State Toxic Algae Freshwater Algae Bloom Monitoring Program
• Additional information on Harmful Algae Blooms - Center for Disease Control and Prevention
• You may also contact our Environmental Health office for more information at (509)-886-6400.