University of Michigan researchers and their colleagues predict a significant bloom of toxic blue-green algae in Lake Erie late this summer.

This year's predicted algae bloom is expected to be larger than average but considerably smaller than the record-setting 2011 event, according to UM aquatic ecologist Don Scavia and colleagues from the U.S. federal government and several universities.

An algae bloom is a rapid buildup of algae in a body of water, and harmful blooms are those that damage other organisms - including humans - through the production of toxins or by other means.

Agricultural practices in the watersheds that feed into western Lake Erie provide phosphorus and other nutrients that fuel large-scale algae blooms.

“Until we reduce the flow of nutrients from croplands into the lake, large algae blooms will likely continue to plague Lake Erie,” said Scavia, director of the University of Michigan's Graham Sustainability Institute.

Researchers say harmful algae blooms were common on western Lake Erie from the 1960's to the 1990's.

After a lapse of nearly 20 years, they have been steadily increasing over the past decade.

Since 2008, the National Oceanic and Atmospheric Administration, has issued weekly harmful algae bloom bulletins for western Lake Erie as an early warning system to track bloom development.

Blooms of blue-green algae can produce toxins that may taint drinking water and recreational water.

People who drink or swim in water that contains high concentrations of these algae or the toxins may experience gastroenteritis, skin irritation and allergic responses, according to the U.S. Centres for Disease Control and Prevention.

In addition, algae blooms can stink up harbours, clog boat motors, reduce fish populations and sometimes lead to the formation of low-oxygen “dead zones” where most aquatic life cannot survive.

The 2014 Lake Erie seasonal forecast is based on two computer models. One was developed by the National Oceanic and Atmospheric Administration. The other is a jointly funded effort of the University of Michigan Water Center and NOAA’s Great Lakes Environmental Research Laboratory in Ann Arbor.

“Issuing and evaluating these seasonal forecasts improves our understanding of how the blooms form, which leads to strategies to reduce their impacts,” said Richard Stumpf, NOAA’s ecological forecasting applied research lead.

In addition to the satellite monitoring of the lake, NOAA’s Ann Arbor lab, Ohio State University’s Sea Grant Program and Stone Laboratory, Heidelberg University, the University of Toledo and the Ohio Environmental Protection Agency will collect key measurements from the lake as the summer progresses. That information will be shared with regional managers and will help NOAA scientists further refine the forecast models.

“This NOAA model, resulting from a great collaboration, has been incredibly valuable to us as we work to eliminate blooms to protect human health, the Lake Erie ecosystem and its coastal economy,” said Jeff Reutter, director of Ohio State University’s Sea Grant program and Stone Laboratory.