CHRISTY MCDONALD, Detroit Public Television:

Lake Erie has long been considered the canary in the coal mine for the Great Lakes system.

The southernmost, warmest, and shallowest of the five lakes, Erie provides an ideal habitat for an unwelcome summer visitor, algae, particularly the toxic kind that caused drinking water problems for Toledo, Ohio, several weeks ago.

And that makes it an ideal place to look for solutions to that problem. Here at the Stone lab in Put-in-Bay, Ohio, they have been studying algal blooms since the '70s. At that time, significant improvements were made to sewage treatment plants, ushering in 30 years of improved health for Lake Erie.

But in the early 2000s, large algal blooms started to reappear, with the worst on record occurring in 2011.

For Jeff Reutter, director of the Ohio Sea Grant College and Stone Lab at the Ohio State University, that algae bloom was like nothing he'd seen before.

JEFF REUTTER, Director, Ohio Sea Grant College and Stone Lab, Ohio State University: The bloom in 2011 really got everybody's attention. That bloom was two-and-a-half times worse than anything we'd ever seen before. And it was really a bloom like I'd never experienced and I have been working on Lake Erie since 1971. And I have seen these before, but I had never seen a bloom that when you hit it with a boat, it actually slowed you down, it was that dense.