COLUMBUS, Ohio - A midsummer algal bloom again is turning western Lake Erie's waters green. While it's predicted to become fairly severe, researchers say it could be worse.
The severity of this year's bloom is forecast to be a 7.5 on a scale of zero to 10. Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University, said that's larger than last year, but smaller than in 2015 when a bloom exceeded the scale at 10.5. She said this year's bloom started to form a couple weeks ago.
"It was fairly mild, not much there," she said, "but it seems like it's really shown up with this heat wave that came through. It's moving around, it's growing in some spots and not in others, or it's starting to get mixed into the water column in different ways. Any of these things are possible."
Johnson said the current algal bloom stretches from Maumee Bay north along the Michigan coast, and about 30 miles east along the Ohio coast to the Portage River. The bloom is expected to stay confined to the western basin and peak in September.
Algal blooms are connected to phosphorus runoff from agriculture. Given the amount of rainfall this spring, Johnson said, a much larger bloom would be expected. However, unusually wet weather last fall and into the spring reduced the amount of phosphorus fertilizer farmers were able to apply.
"If we can win one thing from how difficult this year has been for our agricultural community," she said, "that is that we have a better understanding of how important the application of phosphorus is from one given year on what is actually happening months later, down the road."
Johnson said the current dynamics indicate that applying nutrients below the surface is a promising practice for farmers.
"So, trying to get that phosphorus or nitrogen off of the surface of the soil and injected into the soil more, where it has more interaction and it's in the root zones of these plants, that's going to be effective," she said. "That's what this year is telling us is, is that playing around with those application rates is really important."
Toxins in algal blooms are dangerous for people and animals, and hamper local fishing, boating and other recreational activities. Toxic blooms can be costly for cities that need to treat drinking water.
The bloom forecast is online at tidesandcurrents.noaa.gov.
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