The bad news about this year’s Lake Erie algal toxins is that the harmful blooms are likely to be “significant” and could range up to 9 on a severity index that has only gone over 10 once.
That would make this year’s algal blooms potentially the worst since 2015, when they hit 10.5 on the severity index, the highest ever recorded.
The even worse news is that this year’s blooms — both in western Lake Erie and in Sandusky Bay, where they are produced by different types of toxin-producing algae — are already yielding small amounts of microcystins, the liver toxin that can kill pets and livestock, close beaches and threaten public water supplies.
And even as the toxic algae return to threaten one of Ohio’s most important economic and natural-resource assets, the state lacks a clear plan of attack for reducing their cause: phosphorus and nitrogen runoff.
The chief culprits in this runoff are known: Prior studies by the Ohio Environmental Protection Agency identified fertilizer, manure and other runoff from farms and livestock operations in the Maumee basin as the main sources feeding western Lake Erie’s toxic algal blooms.
But opponents to credible plans to reduce this runoff are powerful. An effort by Gov. John Kasich last year, late in his administration, to kickstart the planning and regulatory process needed to reduce Maumee basin runoff was stymied by powerful agricultural interests.
Since taking office, Gov. Mike DeWine has been silent on whether he will initiate a similar directive.
DeWine has not been silent about Lake Erie, however.
He has pledged to reduce Ohio’s phosphorus runoff as part of regional efforts to cure the algal problem. He’s properly called Lake Erie a jewel. He’s asked the legislature for a nearly $1 billion H2Ohio fund to pay for freshwater protections throughout the state.
But none of these adds up to a real game plan for phosphorus reductions where it counts, in the vast watershed of the Maumee River feeding these nutrients directly into Lake Erie. As our editorial board has said more than once, an actual phosphorus reduction plan is critical.
The harmful algal bloom forecast released Thursday by the National Oceanic and Atmospheric Administration and its partners is just a prediction. It includes a severity forecast of 7.5 for this year’s blooms, just below 2017’s 8.0, and a possible range from 6 to 9.
The rainfall this spring and early summer — rainfall that’s expected to make the blooms more severe — also has kept lake temperatures relatively cool, delaying the predicted onset of the worst of the blooms until later this month.
There’s an additional unknown, however: The toxicity of a bloom doesn’t correlate with its size. And scientists don’t know what causes some algal blooms to be more toxic than others. The 2014 bloom that cut off Lake Erie drinking water to nearly half a million people in the Toledo area, for instance, registered at less than 7 on the severity scale — lower than the predicted severity rate this year.
NOAA and allied researchers, including at Ohio universities and the Ohio Sea Grant and Stone Laboratory, are actively investigating what drives a bloom to produce large amounts of the potentially lethal microcystin liver toxins.
As just one venture, NOAA and others are using unmanned underwater vehicles to assess the depth of toxins and gather samples for later genetic analysis.
Researchers from Bowling Green State University’s Great Lakes Center for Fresh Waters and Human Health, meanwhile, are trying to understand what’s behind toxic algal blooms in Sandusky Bay. There, the blooms trace to Planktothrix, a type of microcystin-causing algae that feeds off nitrogen rather than phosphorus. It turns the water a lighter green than the pea-green algae of western Lake Erie.
Such research is critical. But the only way to reduce the persistently harmful algal blooms in western Lake Erie is to attack them at their source: the agricultural runoff from the Maumee basin that fuels them in the first place.
If Gov. DeWine truly believes Lake Erie is the jewel it is, he must act to create a credible, practical, enforceable plan — in consultation with farming interests, but not in thrall to them — that will finally reduce phosphorus and nitrogen runoff.