Great Lakes Fact Sheet #5: Algae

File Size4.61 MB
PublishedMarch 9, 2013

Phosphorus and Algal Blooms
How did our Great Lakes turn green?

By the mid-20th century, the phosphorus compounds entering the Great Lakes from agricultural and urban runoff, industrial discharges, untreated sewage, detergents and atmospheric deposits had helped to create the ideal conditions for the proliferation of algae.

Historically, there have been successful initiatives undertaken to manage algae. However, new variables, including climate change, invasive species and changes in land use and agricultural practices, have resulted in an algal resurgence affecting the lakes.