What to do when a bay blooms bright blue …and green

Cyanobacterial bloom on Chicaugon Lake. Photo by Chris Wentworth.

By Vicki Browne
Iron County Lakes & Streams Partnership
On Aug. 23 three property owners looked out onto Chicaugon Lake and saw something none had ever seen before: bright blue and green swirls near the shore in a shallow bay. My neighbor and I were two of those people, and the third person was at the opposite end of the lake. 
I had written an article earlier this summer about the differences between filamentous algae and cyanobacteria. This nearly neon-colored bloom did not look like filamentous algae. Trying to scoop some out with a net merely swirled the particles around, confirming that it was definitely not filamentous algae. 
It was time to get confirmation from experts. Jen Ricker-Feak at the Iron Baraga Conservation District encouraged us to send pictures to Sally Hedtke at White Water Associates, a consulting firm based in Amasa. We also sent pictures to algaebloom@michigan.gov, which is monitored by the Michigan Environmental Assistance Center. John Matousek, an aquatic biologist with the Michigan Department of Environment, Great Lakes and Energy confirmed, as did the biologists at White Water Associates, that the bloom looked like cyanobacteria.
“This does look like a possible cyanobacterial bloom which can potentially produce toxins,” wrote Matousek. “Our guidance is to keep pets and people out of the visible bloom. Areas of the lake with clear water can be used for recreation.”
Jay Parent, supervisor for the Marquette District Office of EGLE, was dispatched to Chicaugon Lake to test the bloom for toxins. Parent took a sample and conducted a ‘rapid’ test for toxins. The process had multiple stages, took almost an hour, and revealed no toxins present. The remainder of the sample would be sent on to Lansing for further testing.
Parent indicated that cyanobacterial blooms do occur in the U.P. and that conditions must have been right at both ends of the lake for blooms to appear in three distinct locations. 
“This is a natural phenomenon,” Parent said, adding, “We have never had a positive test for toxins in this region.”
Blooms will occur, especially later in the summer. They also dissipate fairly quickly. 
“They sent me out immediately,” said Parent. “By the time I get there the bloom has usually disappeared.”
The recommendations whenever a potential cyanobacterial bloom occurs on any lake are:
1) Do not swim or fish in the area.
2) Keep pets away as blooms are particularly dangerous for pets.
3) Send a photograph to algaebloom@michigan.gov