Great Lakes Region


Left: A harmful algal bloom in western Lake Erie (Credit: NOAA GLERL).
Right: A dead fish surrounded by algae along the southeast shore of Pelee Island, Ontario, in Lake Erie, during a record-setting algal bloom (Credit: Tom Archer, 2011).

What are Harmful Algal Blooms (HABs)?

Harmful Algal Blooms (HABs) are characterized by an overgrowth of algae in water, or an algae bloom. The algae bloom occurs when single-celled organisms, including algae and dinoflagellates, reproduce rapidly due to certain conditions being present, such as high nutrient levels or slow-moving water.

Algae blooms become harmful to the ecosystem when the blooming organisms contain toxins, noxious chemicals or pathogens, which can lead to death of nearby fish and produce harmful conditions to marine and human life.

What causes an algal bloom?

The presence of nutrients, warm temperatures and light encourage the growth of algae in our waterways. While an increase in temperature and light is primarily caused by natural factors, an increase in nutrient level is largely due to anthropogenic factors, such as poor farming practices. Poor farming practices result in increased levels of phosphorus in the water due to high use of fertilizers and the presence of livestock near water supplies.

What are the dangers?

HABs can…

  • Spoil water quality by producing odors or thick scums
  • Cause drinking water to taste and small bad
  • Decrease scenic beauty of recreational areas
  • Kill fish by decreasing oxygen levels
  • Can contain cyanobacteria, which are poisonous to humans and deadly to livestock and pets

What are we doing about them?

The Great Lakes Environmental Research Laboratory (GLERL) and the Cooperative Institute for Great Lakes Research (CIGLR) are working to identify factors that influence HABs, as well as developing methods to forecast cyanobacteria blooms. The research is aiming to predict the time at which algal blooms will occur, whether or not they are toxic, and their impact on human health. GLERL researchers are monitoring six master stations and two fixed mooring in western Lake Erie, a site highly susceptible to HABs. The information gathered from these stations will be used to develop a probabilistic model for HABs in Lake Erie.

Lake Erie HABs Tracker: The HABs tracker is a tool that uses remote sensoring, monitoring and modeling to produce five-day forecasts of bloom transport and concentration. Click here to view the Lake Erie HABS tracker now!

NOAA Facebook NOAA Twitter RSS Feed for this site Email Us NOAA's Flickr Feed