This image by NASA from July 28 shows algal blooms near Toledo, Ohio.
This image by NASA from July 28 shows algal blooms near Toledo, Ohio. - 
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Last year’s toxic algae bloom in Lake Erie was so bad it shut down the water supply of Toledo, Ohio. This year’s is expected to be worse, and Congress has ordered the EPA  to work on a solution

The EPA can’t do much about one factor driving these algae problems: Climate change. Algae like it warm. However, people could give the algae less to eat, according to Timothy Davis, who studies harmful algae blooms for the National Oceanic and Atmospheric Administration. 

"If you limit the nutrition, you limit the size and toxicity of these blooms," Davis says.

Most important is to limit the phosphorous hitting the lake. According to Laura Johnson, a research scientist from Heidelberg University's National Center for Water Quality Research, the biggest problem is a form called "dissolved phosphorous," which comes from farms.

"It’s really yummy stuff for algae to use," Johnson says. "They grow explosively when they have dissolved phosphorous."

One possible remedy would be to inject fertilizer into the soil, instead of spreading it on top, where rain can wash it away. Injecting fertilizer would require new expensive gear, but Johnson says there might be some compensatory savings for farmers.

"If you’re losing phosphorous off your soil, you’re losing something that you applied," she says. "And anything that’s running off is lost money."

However, she admits the savings might be small. Studies show that in the most critical region, around the Maumee River, only about one percent of the phosphorous applied shows up as runoff. "That's pretty efficient," she says.

Follow Dan Weissmann at @danweissmann