Toxic blooms still threaten Lake Erie

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Capital News Service

LANSING — Toxic algae blooming in Lake Erie is creating safety concerns for humans and aquatic life, prompting the state to work with farmers to reduce the phosphorus levels in field runoff. 

Algal blooms have left parts of the Great Lake’s surface green, slimy and covered with scum. The scum is often found in areas with high levels of blue-green algae, or cyanobacteria. 

The bacteria produces cyanotoxins which can be harmful to humans and wildlife.

Other parts of the lake water may only be slightly green, but can still be just as toxic, said Craig Stow, a scientist at the National Oceanic and Atmospheric Administration’s (NOAA) Great Lakes Environmental Research Laboratory in Ann Arbor.

“Just because you don’t see the scums – sometimes the water may just appear to be kind of an off-green color – it doesn’t mean those algae aren’t there,” Stow said. “Sometimes they’re just dispersed in the water and may still be producing toxins or other nuisance kind of effects.”

The factors that cause that toxicity are not well understood as algal blooms can also be green and slimy without being toxic, and size has no effect, he said.

Blooms appear in ecosystems that receive an excess of nutrients like nitrogen or phosphorus that the algae feed on.

Lake Erie faced the same problem in the 1960s and 1970s, Stow said. Too much phosphorus was entering the lake in wastewater from sewage treatment and industrial plants. The state took measures to reduce phosphorus levels in the late 1970s, and conditions improved by the 1990s.

Then, the blooms returned, from a new source, in the 2000s.

“It seemed that we had fixed the problem in Lake Erie and we were good to go,” Stow said. “But as we’ve learned more, we’ve recognized that they aren’t really broken or fixed. You can control a problem through management and that control has to be ongoing and may not have a clear end point.”

The current algal blooms have caused areas of Lake Erie to turn green, slimy, and often foul- smelling, making the water undesirable for activities like swimming and fishing. In some places, cyanotoxins from blooms can harm water quality in surrounding cities.

The bloom occurs predominantly, but not exclusively, in western Lake Erie, Stow said. The size varies each year depending on the flush from the Maumee River, a main input of nutrients into the lake.

This year, NOAA has also spotted blooms in Sandusky Bay and further east in the central basin of Lake Erie.

The main source of Lake Erie phosphorus is agricultural water runoff because of its common use in fertilizer, said James Johnson, the director of the Environmental Stewardship Division in the Department of Agriculture and Rural Development.

“Phosphorus is a naturally occurring thing,” Johnson said. “Algae actually feed on phosphorus. Algae actually tends to be a very basic form of any healthy aquatic system, but too much algae actually ends up being a problem.”

Johnson helped write Michigan’s Adaptive Management Plan for Lake Erie. It’s part of the Lake Erie Domestic Action Plan, a larger guide towards making the lake a healthier ecosystem.

The plan specifically identifies steps Michigan agencies will take towards reducing phosphorus levels and how they will collect and analyze data to adjust the course of action through repeated work plans.

Johnson said reducing phosphorus levels is a significant challenge because many decisions must be made and there’s no one-size-fits-all solution.

Each agricultural field is different, so agencies will need to work with growers field by field to implement best management practices for each one. These are structural, vegetative or managerial practices to reduce water pollution.

And there are a lot of options.

Potential practices include changing the application and amount of applied nutrients and reduced tilling practices so organic material like weeds grow on a field’s surface to slow the movement of water in rainstorms.

The goals include reducing phosphorus entering the lake from U.S. and Canadian watersheds by 40%.

However, it may be tough to reach those goals in within five years because of how complex the solution is to the algal bloom problem.

“We’re going to struggle to meet our goals by 2025,” said Michael Alexander of the Water Resources Division in the Department of Environment, Great Lakes and Energy. “We’re hopeful that we can, between now and 2025, show a significant amount of progress and have a better understanding of how we can be successful and meet all of our goals, but it’s going to be difficult.”

The public comment period in June showed the plan needs clarification on what practices to implement and better documentation on watershed planning, Alexander said. 

Taylor Haelterman reports for WKAR Radio and Great Lakes Echo.

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