Lake Erie's severe algal bloom in 2019 stirs worries about 2020

Leonard N. Fleming
The Detroit News

Just ask David Spangler how algal blooms have hurt his charter fishing boat business that operates in Lake Erie, and he will give you chapter and verse about the harmful green slimy substance.

"The unique thing about this particular stuff is, it's buoyant. It floats," said Spangler, who is based in Oak Harbor, Ohio. "When the lake gets very quiet and goes very calm, this stuff just pops right up to the surface. And if you've seen some of the pictures, it looks like you may have dropped green carpet on top of the water, it's that thick."

A long-range autonomous underwater vehicle or robot swims through Lake Erie measuring concentrations of algae in August 2019.

Algal blooms on western Lake Erie this past summer where Spangler has his Toledo area Dr. Bugs Charter business were more severe than the previous year. They could be on the upswing if a wet spring soaks the region in 2020, federal experts said.

This year's harmful algal bloom, according to Michigan officials from the National Oceanic and Atmospheric Administration who track it, had a "severity index" of 7.3 compared with 3.8 in 2018. The bloom index, which captures the amount of bloom biomass over the peak 30 days of a bloom, was 8.0 in 2017.

The annual occurrence of blooms in Lake Erie is caused by an overabundance of nutrients like phosphorus in the water that are fueled by fertilizer runoff and make their way into the watershed.

Although the algal blooms have fluctuated in recent years depending on the amount of rainfall, the amount of blooms have trended upward since 2008, federal researchers said. The largest blooms occurred in 2010 with a severity index of 10 and 10.5 in 2015.

While the harmless algae doesn't kill fish, it does contain materials that lower oxygen levels that hurt marine life and are harmful to humans.

Experts said it's too early to predict what blooms will happen next summer but wet springs do make them stronger.

"We've either been for the last 10 years either in a cycle of wet springs that we may come off for a while or we've in fact seen climate change so we are in more frequent wet springs," said Richard Stumpf, an oceanographer with NOAA's National Centers for Coastal Ocean Science who studies blooms.

Experts like Stumpf said this year's bloom, which ran from July to October, was the strongest in August. But a windy September "caused it to weaken and not really strengthen," he said.

An algal clump floats in Lake Erie on Aug. 19, 2019.

From canceled bookings to a frantic search for spots to fish, Spangler and others have lost income fishing for walleye because of the blooms.

"We typically run April to the end of October, and if you take a six-, seven-, eight-week slot out of there, you can't make that up," he said. "We're getting hit with 15, 20 and sometimes 20 to 25% of our business is lost because we just don't run out."

The trend is that blooms are starting earlier and lasting longer given the amount of rainfall, said Reagan Ererra, a research ecologist with the NOAA's Great Lakes Environmental Research Laboratory based in Ann Arbor.

Lakes Huron and Ontario, as well as Saginaw Bay, do experience some blooms but "Erie is unique because it's shallow and it's warm, so it creates more of a perfect location for these blooms to occur," Ererra said.

"If nutrients keep coming down, we're probably going to have a toxic bloom to begin with that then moves into a non-toxic bloom," she said. "And with increased water temperatures, it's expanding the length of period in which they can bloom. So less colder days, wider expanse of them taking advantage of the warmer waters."

Researchers prepare to drop an environmental sample processor into Lake Erie to measure the severity of algal blooms in July 2019.

The Maumee River's draining into Lake Erie and the heavy concentration of agriculture in the area bring "a concentration of phosphorus" that is much higher than some of the other lakes and rivers, Stumpf said.

Ererra said the increased runoff and precipitation "seem to be a new staple within our ecosystem that we're dealing with."

"Year to year we're going to have fluctuations," she said, mentioning how 2016 was a drought year. "Because of that, the bloom actually never really took off."

Stumpf said that in most cases when a bloom has occurred, "there's no getting around it and you need to plan" if you are a boater, fisherman or swimmer."

"We try very hard to people not where the blooms are but where they are not," he said. "It doesn't cover the whole lake. It doesn't cover the whole western basin."

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Twitter: @leonardnfleming