Lake Erie’s Sandusky Bay is already struggling with a species of toxin-producing algae, another sign that the rest of the lake’s western basin is likely headed for another massive bloom this summer.
Called planktothrix, Sandusky Bay’s dominant form of cyanobacteria — or what most people euphemistically simply call toxic algae — differs from microcystis in how it grows and how it responds to anything from sunlight to phosphorus. Microcystis has been the most dominant type of harmful algal bloom in the vast majority of western Lake Erie since at least 1995.
Why is it that one form of algae tends to take over Sandusky Bay and another tends to take over the rest of the lake’s western basin and occasionally move into its central basin?
That’s one of the great mysteries of science. After all, it’s the same lake.
But here’s the most important thing to know: Both planktothrix and microcystis produce the same toxin, microcystin, that’s been found to be one of the most potent, naturally occurring toxins in nature.
It has the capability of killing people, as it did when about 75 people died at a kidney dialysis center in Brazil when on-site water treatment broke down nearly 25 years ago. It’s more potent than arsenic and saxitoxin, a toxin associated with shellfish poisoning that can paralyze and kill humans.
So far, the microcystin levels found in Sandusky Bay have been relatively low and not a threat to drinking water systems.
George Bullerjahn, director and principal investigator of Bowling Green State University’s Great Lakes Center for Fresh Waters and Human Health, said results from a June 10 sampling showed some of the raw Sandusky Bay water had toxin levels over 20 parts per billion, the advisory limit for human body contact but well within what water-treatment plant operators typically deal with.
And even with all of the rain, the planktothrix — which almost always arrives before microcystis — didn’t arrive particularly early when it started to form in May. A big difference, though, is that it didn’t take long before it looked almost as thick as blooms do in July.
Planktothrix has been known to stay as late as November, Mr. Bullerjahn said.
Microcystis was found in the open water in June, 2018. In years past, it might not have formed until August and usually vanished by early to mid-October.
Satellite tracking shows the Sandusky Bay’s planktothrix bloom is already moving beyond the bay into the open lake water near Cedar Point. That doesn’t always happen, because wind often keeps it somewhat confined to the bay, Mr. Bullerjahn said.
“This happens sometimes, but is not common,” said Rick Stumpf, an oceanographer from the National Oceanic and Atmospheric Administration who heads up Lake Erie’s algae-forecasting program.
It was documented leaving Sandusky Bay and mixed into the open western Lake Erie water via satellite Tuesday, Mr. Stumpf, part of NOAA’s National Centers for Coastal Ocean Science in Maryland, said.
“Heavy rain increased the Sandusky River discharge, pushing the planktothrix bloom into the lake,” he said.
So now, with this spring’s unusually heavy rain — which kept many northwest Ohio farmers from planting seed and fertilizing their fields — one of the big research opportunities will be gauging the residual threat of so-called “legacy” phosphorus.
Legacy phosphorus is what has embedded in soil for years, as opposed to the most recent springtime application. It’s been hard distinguishing between the two, but it could be easier this year if less manure and commercial fertilizer was applied because of the rain.
Environmental activists have questioned this spring if massive lagoons holding manure produced by large livestock facilities — known as concentrated animal feeding operations, or CAFOs — have overfilled and spilled into area creeks and tributaries. The Ohio Department of Agriculture told The Blade a couple of weeks ago it had not seen anything out of the ordinary.
Planktothrix is the same algae that overwhelmed Ohio’s Grand Lake St. Marys with a record bloom in 2010. It has been known to alternate with microcystis as the nuisance species in the Maumee River as far away as Defiance. It also has been found in South Florida’s Lake Okeechobee.
Nitrogen, not phosphorus, is the main driver behind it. It can grow quite well under low-phosphorus conditions, as long as it has an abundance of nitrogen to feed off.
Planktothrix differs from microcystis in that it is evenly suspended in the water. It also has a much lighter color than the darker, pea green hue of microcystis.
BGSU, which has taken the lead on Sandusky Bay algae research, now has eight sites it samples for planktothrix regularly.
Researchers are scheduled to meet on Gibraltar Island’s Stone Laboratory for their final 2019 summer algae prediction for western Lake Erie. NOAA, Heidelberg University, Ohio Sea Grant, and others are now predicting this year’s bloom will be one of the more severe ones since record-keeping began in 2002 because of all of the rain, probably a 7 or higher on a scale of 10.
First Published June 28, 2019, 7:43 p.m.
