Adam Heathcote has been studying blue-green algae blooms for more than 15 years, including a lot of work in lakes in Iowa and southern Minnesota surrounded by farms and other development, where it’s common to see severe algae blooms. 

But that didn't prepare him for what he saw last month in the Boundary Waters Canoe Area Wilderness, when he paddled into Burnt and Smoke Lakes — two small lakes off Sawbill Lake, a popular BWCA entry point north of Tofte.

"That was as bad of a bloom as I saw in Iowa during my entire PhD, in a lake that was two portages into the Boundary Waters,” said Heathcote, who directs the Department of Water and Climate Change at the St. Croix Watershed Research Station, part of the Science Museum of Minnesota. 

"I had never seen a bloom to that extent where it was like thick, neon-blue, neon-green paint, lake-wide, not just [in] a little isolated bay,” described Heathcote. “Two of the three lakes that we sampled in the Boundary Waters had this going on across pretty much their entire surface area."

Heathcote was taken aback because these lakes are protected; they're surrounded by wilderness.