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Flooding may spur algae in Lake Erie

2018-03-02  |   Editor : houguangbing  

The torrential rains that have pounded Ohio in the past few weeks have flooded basements and sent creeks spilling into roadways. They also could mean bad news for Lake Erie in this summer. Besides the damage they caused of homeowners and drivers, rains swelled rivers across the state, including near Toledo, which got its average rainfall of more than doubled.

That made this June the fourth-wettest in Toledo's history, according to the National Weather Service.

Those same rains soaked farm fields in northwestern Ohio, then washed into the creeks that feed the Maumee River, a major source of the type of pollution that causes toxic algae blooms to form in the lake each year.

Data from the U.S. Geological Survey show that the Maumee sent more water into Lake Erie in this June than in any June since 1930, when the survey first started tracking the river's outflow.

More water from the Maumee means more pollutants, which was likely to mean a bigger Erie bloom than those scientists anticipated at the start of the month.

"The fact that it's a record of June is unfortunate for the lake," said Rick Stumpf, an oceanographer and toxic-algae expert with the National Oceanic and Atmospheric Administration. "More rain means more runoff, which means there will be more phosphorus going into the lake."

Phosphorus is present in manure and sewage, and is a key ingredient in many commercial agricultural fertilizers. It’s the thing that helps plants grow. But as it feeds crops, it also feeds the toxic algae that coalesce in Lake Erie each year.

A bigger phosphorus load means a bigger algae bloom.d Cause problems for swimmers, boaters and public-drinking-water systems.

A group of scientists, including Stumpf and researchers from Ohio State University and Heidelberg University, plan to announce their official algae bloom prediction on Thursday at Ohio State University’s Stone Laboratory, on Gibraltar Island.

They are still analyzing some of the data. But early forecasts show the bloom will likely be larger than scientists originally thought this year because of the drenching rains that inundated Ohio last month.

Until June 1, phosphorus loads in the Maumee were about average, according to data from both the National Oceanic and Atmospheric Administration and Heidelberg University’s National Center for Water Quality Research.

But after June 1, and especially over the last two weeks, the level of phosphorus in the Maumee River spiked.

That's important, because the severity of the annual Lake Erie algae bloom is directly connected to the amount of phosphorus in the lake.

The bloom likely won't be as bad as the one in 2011, when algae stretched from Toledo to Cleveland. But it probably will be worse than last year, when a smaller bloom settled around Toledo’s public drinking water intake and made tap water unsafe for some 400,000 people.

Laura Johnson, a research scientist at the Heidelberg Center for Water Quality Research, said torrential downpours in June are better for the lake than torrential downpours in August.

Farmers already have planted crops, she said, which can help keep phosphorus on the fields.

And the severity of this year's bloom will depend in part on the lake's temperature. Algae tend to grow better in warmer water than cooler. Lake Erie tends to get more severe blooms than other Great Lakes because it is the shallowest, and most easily warmed, of the five.

Thursday's algae forecast also will likely include conversations about recommendations from the United States and Canada to cut the amount of phosphorus that gets in Lake Erie by 40 percent. Ohio, Michigan and Ontario announced last month that they plan to make those reductions by 2025, and pledged "an aspirational goal" of cutting phosphorus runoff 20 percent by 2020.

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