Lake Erie toxic algal bloom may be smaller than last year’s

By: Kevin Bunch | C&G Newspapers | Published June 26, 2015


According to researchers, the annual bloom of harmful algae on Lake Erie is on track to be on par with the 2009-10 blooms, though still smaller than last year’s bloom that saw the shutdown of the Toledo water system.

The National Oceanic and Atmospheric Administration released its preliminary report June 15 on what it expects from Erie’s bloom this year, with a more accurate one coming in early July.

“The official NOAA seasonal forecast will be made on July 9,” Tim Davis, a NOAA harmful algal bloom research scientist, said. “So far, it’s looking like a moderate bloom.”

According to NOAA’s Great Lakes Environmental Research Laboratory, harmful algal blooms are found in all the Great Lakes, including Lake Huron’s Saginaw Bay and Georgian Bay and Lake Michigan’s Green Bay. They also occur in Lake St. Clair.

While the cyanobacteria that causes the harmful blooms is native to the lakes, the circumstances behind its excessive proliferation each year have changed over the decades. Davis said algal blooms recorded from the 1960s and ’70s occurred due to point-source pollution from factories and industry dumping into the waterways. Once the Great Lakes Water Quality Agreement was signed in 1972, those blooms cleared up. Lake Erie was considered relatively healthy and clean. Algal blooms re-emerged in the 1990s and have continued to be an issue up to today.

“These cyanobacteria are a natural part of the phytoplankton assemblage in the lakes,” Davis said. “It’s when conditions are right that they grow into these blooms we see today — so the blooms we see are (the) visual manifestation of poor lake quality.”

Michigan State University Extension Sea Grant Educator Steve Stewart said a particular genus of cyanobacteria, Microcystis, is the most common one in western Lake Erie and in the Saginaw Bay.

Some algal blooms are harmless “green algae” species that are not toxic, Stewart said, but the “blue-green algae” like the cyanobacteria can foul coastlines, kill fish and birds, and lead to the closure of water systems, like what happened in Toledo last summer. It is not easy to tell the difference just by sight, and the toxins from those harmful species can lead to some adverse effects on humans who make contact with them.

“Most people aren’t going to swim in waters where there are known harmful algal blooms, so use common sense. When you get out of the water, rinse off with fresh water, rinse your pets, and avoid contact with water where you know there is some kind of bloom going on,” Stewart said.

Davis said the harmful blooms are now driven by nutrients getting loaded into waterways, most notably phosphorus and nitrogen. Phosphorus tends to enter the lakes when farmers put down too much fertilizer and rain events wash it into waterways.

He said nitrogen can come from fertilizer, the atmosphere itself, or from major cities following storm events. The element can be found in wastewater, and in older combined water systems, heavy rainfall can cause wastewater to get dumped directly into the lakes without treatment. Fertilizers drive the bulk of these nutrients, though, he said, particularly along the Maumee River basin leading to Lake Erie.

“If you put (fertilizer) down and it rains immediately, more of it goes into the river and gets into the lake,” Davis said. “If you put it down at times without much rain, there is more chance of the fertilizer moving down into the soil, and it’s less likely to run off into the rivers.”

Due to the size of the Great Lakes, the kinds of on-site control efforts that work on smaller inland lakes are not feasible on those waters, he added, so the best way to deal with it is to prevent phosphorus and nitrogen from getting into the lake.

Stewart said there have been efforts to reduce the amount of phosphorus getting into the lakes, as it has been removed from household lawn fertilizers and detergents. There have also been efforts to reduce nutrient loading from agriculture.

Water systems with separated sewer lines do not see the same overflow issues during storm events as combined sewer lines, though according to Eastpointe Department of Public Works Director Mary Van Haaren, the high cost of putting down separated lines in older systems does limit what communities can do.

“It would be better for the area to have them all separated, but it’s enormously cost-prohibitive,” Van Haaren said. “You can imagine putting a brand-new sewer system in a developed area.”

Davis said Detroit Water and Sewer as a whole has made inroads in upgrading its system.

Invasive species like zebra mussels could also be contributing factors to the blooms, Davis said. Species like zebra mussels release phosphorus as waste after eating harmless green algae and other plankton, producing another source for Microcystis as well as clearing space in the ecosystem for it to flourish.

Microcystis can grow with sunlight, nutrients and water like any other plant, Davis said, but once they start dying at the start of fall, other bacteria that eat their remains suck up all the oxygen in the water, which can lead to fish kills. The Microcystis itself is also toxic, so water that has a bloom on it is not safe to drink.

Climate change may lead to more severe blooms, Davis said, as Microcystis prefers to grow in warmer waters. Algal blooms tend to form when water gets above 59 degrees Fahrenheit, reaching a growth peak when waters hit 77 degrees. Microcystis’s growth rates are tied into warmer temperatures more than other species.

Stewart advised people to contact their local health departments to see if algae are blooming on a lake, and to be mindful of any posted warnings at the beach.

The Environmental Protection Agency plans on releasing a smartphone app this year to show where algae blooms are forming — and what kind — to help water treatment facilities and park managers prepare and plan for blooms before they are a danger to health and safety.