A team of researchers led by Bob Sterner, director of the Large Lakes Observatory at University of Minnesota Duluth, has identified two major factors that contribute to the presence of cyanobacterial algae blooms on Lake Superior, and one of them is already in play.

“It’s been a warm year and past blooms have happened in warm years,” Sterner said in a news release Tuesday from UMD. “The other factor we’re looking for is a major weather event or historic rainfall.”

Sterner is the lead researcher of a group at UMD, partnered with the National Park Service, that has been gathering and examining data on algae blooms along Lake Superior’s southern shore since 2011 to get a better understanding of what causes them.

Bob Sterner
Bob Sterner

Sterner is also part of a broader Algal Bloom Response Team that is sharing information and coordinating resources to monitor and eventually help protect Lake Superior from toxic blooms that could have a devastating impact on lake economies, the release said.

The Response Team includes representatives from Northland College in Ashland, Wisconsin Department of Natural Resources, the Environmental Protection Agency, the National Park Service and the Red Cliff Band of Lake Superior Chippewa.

Sterner explains that the broader involvement of these agencies improves researchers’ ability to learn of blooms that pop up and to respond and gather more information. The public has a part to play in assisting this effort, too.

“Floating green scum indicates a bloom and we’d like people to take photos, note the location, size of the bloom, place and time and, if it can be done safely, collect a water sample,” Sterner said in the release.

The University of Minnesota Duluth and National Park Service have been researching algae blooms along Lake Superior’s southern shore since 2011. (Photomicrographs by Gina LaLiberte / Wisconsin Department of Natural Resources)
The University of Minnesota Duluth and National Park Service have been researching algae blooms along Lake Superior’s southern shore since 2011. (Photomicrographs by Gina LaLiberte / Wisconsin Department of Natural Resources)

The first documented Lake Superior bloom occurred in 2012. Another, even larger bloom in 2018 provided an opportunity to gather valuable data. No evidence of toxicity in Lake Superior blooms has yet been seen, but Sterner said that certain environmental factors like high nitrogen levels can trigger toxicity.

“Lake Superior is high in nitrogen, but we haven’t seen a toxic bloom yet, so we keep watching,” he said.

Many UMD students have been part of the Large Lakes Observatory research team. Doctoral candidate Kaitlin Reinl spent several months collecting water and sediment samples from nearshore locations and tributaries that feed into Lake Superior and analyzing the data gathered.

“I think most people think of Lake Superior as enormous and pristine, but we’re starting to feel the effects of a changing climate with the lake temperature rising,” Reinl said in the release. “We have an opportunity to be proactive instead of reactive and we need people to be aware of this research and how they can help us.”

To report an algae bloom, email dnrhabs@wisconsin.gov. The response team is unable to test every bloom, but the following details are helpful:

  • Approximate bloom size;

  • Duration;

  • Location with water body name, town name and county name;

  • Photos for verification including close-ups and overall views.

Algae blooms at a Lake Superior beach in August 2018. (Photo by Brenda Lafrancoise)
Algae blooms at a Lake Superior beach in August 2018. (Photo by Brenda Lafrancoise)