Early projection predicts smaller harmful algal bloom than 2020, 2019

PORT CLINTON - For the second consecutive year, experts are anticipating Lake Erie’s seasonal harmful algal bloom will be smaller than the year before, according to the most recent early projection made by the National Oceanic and Atmospheric Administration. 

In 2020, the severity of the bloom was measured by NOAA as a 3 on a scale of 1 to 10, considerably lower than the 7.5 in 2019. 

This year is projected to likely measure between 2 and 3, or the highest potential severity of less than 5, which is still a lower and narrower range than was predicted for the bloom in 2020. 

Bloom prediction based on recent weather conditions 

Tthe bloom is expected to be smaller due to weather conditions over the past several months, according to researchers studying the problem in Lake Erie. 

The severity varies from year to year based on the level of total bioavailable phosphorus, primarily from agricultural runoff after heavy rains reaching the Maumee River during the five-month loading season, which begins in March and runs through July.

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Through March and April, the Maumee River was discharging water into Lake Erie at a below average rate due to lower than average rainfall, which led to low phosphorus loads in early spring.

However, from May through early June, there was somewhat higher than average rainfall.

“While there is still uncertainty in the rainfall for the rest of June, we expect to start into a normal summer weather pattern which is drier than spring,” stated NOAA's June 14 report. 

Algal bloom reports released weekly 

During the early season, which runs from May through June, NOAA issues weekly updates to the projections based on the most recent phosphorus loading data from the National Center for Water Quality Research at Heidelberg University and modeling from the National Weather Service’s Ohio River Forecast Center.

Later this month, NOAA will then issue its more complete annual Lake Erie harmful algal forecast for that season at the Ohio State University’s Stone Laboratory and Ohio Sea Grant on Gibraltar Island, which sits just north of Put-in-Bay.

As experts note any bloom that develops will change with time and move with the wind, following the forecast, NOAA also issues multiple bulletins available to anyone with email access each week during the harmful algal bloom season, primarily July through August.

Despite the second consecutive year of an anticipated smaller bloom, lake experts are still stressing the importance of the need to reduce phosphorus runoff to adequately address the issue, evening during rainier seasons. 

“We’re trying to get nutrients down by 40% relative to 2008,” said Chris Winslow, director of Ohio Sea Grant. 

Target level set by 2012 treaty

That 40% target is based on a treaty signed in 2012 by Ohio, Michigan, and Ontario, Canada, which Winslow explained would result in a bloom that would fall below what is considered an “acceptable” level of severity on an average of nine out of 10 years as described by that agreement. 

Winslow said the phosphorus loading data relative to when rain events occur has shown the timing of when farmers apply nutrients to their fields plays an important role in reaching that reduction goal. 

“The phosphorus that we’re applying in any given growing season, or prior to that growing season, has the potential to run off and we see that,” he said. “And when you don’t apply that phosphorus, you reduce the amount of runoff in that given year.”

There is also an additional impact from what is referred to as “legacy” phosphorus, which means it was applied during a prior growing season. 

jstinchcom@gannett.com 

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Twitter: @JonDBN