Mapping Harmful Algal Outbreaks

Helps Combat Future Threat

Mapping historic harmful algal blooms has increased our understanding of the relationship between blooms and their causal factors and will lead to more effective future management.


In normal concentra­tions, algae are an important component of healthy freshwater systems, but with too many nutri­ents algae can multiply out of control and cause harmful algal blooms. Exposure to contaminated water can result in ailments ranging from liver failure to vomiting and indigestion. Harmful algal blooms can also be fatal to household pets and numerous species of fish and wildlife. Unfortunately, the Great Lakes have seen a dramatic rise in the frequency and severity of harmful algal blooms over the last decade. In 2014, a bloom near Toledo, Ohio, left more than 400,000 people without access to safe drinking water for nearly three days.

Thanks to a grant from the Great Lakes Restoration Initiative, researchers from Michigan Technological University are studying harmful algae bloom trends to help guide future management in Wisconsin’s Green Bay in Lake Michigan, Michigan’s Saginaw Bay in Lake Huron, and the western basin of Lake Erie on the shores of Ohio. Researchers used archived satellite imagery to record the extent and biomass of algal bloom events in these areas from 2002 to 2012. Using these images and other data about nutrients in the ecosystem, researchers were able to improve the quality of their predictive models about when and where algal blooms will strike. Thanks to the results of this monitoring program, health and environmental officials hope to work collaboratively with farmers to find new and creative approaches to fertilization and crop management that will limit nutrient runoff. This study also provides important data on water conditions that can help inform the decision making of fishermen, sailors, beach managers and the general public. Michigan Tech plans to continue monitoring future harmful algal bloom trends to determine the efficacy of these improved practices.

Resource Challenges Addressed

  • Harmful algal outbreaks
  • Agricultural runoff


A researcher gathers a sample of a toxic algal outbreak.

A water sample taken from western Lake Erie during a harmful algal bloom in August, 2013. Photo credit: Michigan Technological University.

Results and Accomplishments

The study provided a fuller understanding of what causes harmful algal blooms, leading to the creation of more advanced models to help researchers target solutions to reduce future outbreaks. Health and environmental officials hope to work collaboratively with farmers to find new and creative approaches to limit nutrient runoff such as altering fertilization schedules, using organic animal waste fertilizers, and establishing riparian buffers between their crops and water bodies to absorb these nutrients before they enter the watershed.