Though western Lake Erie’s 2023 algal bloom season is finally over, a Wisconsin researcher pointed out that the whole mind-set of how the public views algal blooms needs to change as scum formations continue to form earlier, hang around longer, and become more prominent throughout the Great Lakes region and the rest of the world.

Gina D. LaLiberte, a Wisconsin Department of Natural Resources research scientist, made her comments during an hourlong Zoom webinar Wednesday hosted by the North Central Region Water Network, a little-known collaboration between 12 state extension offices in the Midwest. The network has a regional director and a team of extension-appointed state contacts.

Ms. LaLiberte opened her presentation by saying there is often a misguided belief that algal blooms are just something that happens during the peak summer months.

Researchers are finding blooms are much more complicated and resilient than that, with nutrients playing a bigger role than intense heat and sunlight. The clusters of scum formations that algae forms are often more a result of wind, buoyancy, and other factors, she said.

Pea green-colored water usually isn’t from a rush of phosphorus, nitrogen, and other types of nutrients that got into waterways hours or days before blooms are noticed. It’s more likely a result of what entered months earlier, Ms. LaLiberte said.

“The truth is there can be some time-significant inputs,” she said.

Scientists also are finding some cyanobacteria species, the term of blue-green harmful algal blooms, that are adapting to lower-nutrient, cooler water. That’s what has been happening in Lake Erie the past two years when there’s a biological handoff in the fall from warm-weather microcystis to cooler-tolerant dolichospermum, a type of cyanobacteria that used to be called anabaena.

Microcystis and dolichospermum have the potential to release toxins into the water, although this year’s release was lower than in the past.

“It can be really perplexing to people to see blooms in late fall into winter,” Ms. LaLiberte said.

The other speaker featured on the webinar, Anna Boegehold, a researcher with the National Oceanic and Atmospheric Administration’s Cooperative Institute for Great Lakes Research at the University of Michigan, agreed.

She said Lake Erie has “been shifting to dolichospermum” the last couple of years as the lake’s most dominant form of cyanobacteria, microcystis, fades away.

The change is too subtle for most to realize. To the general public, the comeback of dolichospermum simply means longer seasons of algal blooms.

Having one come in right after another has become a puzzle to scientists.

“We have a lot more [work to do] to be able to tell that whole story,” Ms. Boegehold said.

Wisconsin also is finding more evidence of another toxin-producing form of cyanobacteria, planktothrix, surviving beneath ice, Ms. LaLiberte said.

Scientists also don’t know yet why there are more toxins produced some years than others. The size of blooms does not correlate to the amount of toxins produced.

“While not all cyanobacteria can make toxins, those that can don't make them all of the time,” Ms. LaLiberte said.

The standard advice applies to stay away from water that looks like it could have algae in it, no matter the time of year.

“Be especially careful with dogs,” Ms. LaLiberte said. “We've had a number of dog deaths nationally. Be careful around anything if you don't know what it is.”

First Published December 10, 2023, 10:55 p.m.