Algae-bloom boom likely for Lake Erie, water quality researchers predict

With higher-than-average rainfall and sizzling temperatures, conditions are ripe this summer for toxic algae blooms in Lake Erie, water quality researchers predict.

An algae bloom from Lake Erie appears in the boat basin at International Park in Toledo, Ohio, in this 2017 file photo.

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With higher-than-average rainfall, high phosphorus levels entering the lake and sizzling temperatures, conditions are ripe this summer for toxic blue-green algae blooms in Lake Erie, water quality ­researchers predict.

The lake, which creates hundreds of kilometres of Southwestern Ontario shoreline, has been plagued by growth of cyanobacteria, also called blue-green algae, in recent years, a threat to drinking water intakes, marine life and tourism.

A problem especially in the lake’s western basin, one colony a few years ago grew almost as large as Prince Edward Island.

“From all signs, the potential is high for a large bloom event,” said Michael McKay, executive director of the Great Lakes Institute for Environmental Research at the University of Windsor.

A satellite image shows a harmful blue-green cyanobacteria bloom in the western basin of Lake Erie in September 2017. That bloom was an eight on the severity index, compared to this year’s prediction of a 7.5. (National Oceanic and Atmospheric Administration)

McKay, speaking from China where he was teaching, said there’s also worry this season that Lake St. Clair, the small lake into which the Thames River empties, is also at risk for the cyanobacteria blooms.

St. Clair has had cyanobacteria blooms before, including a large one in 2015.

The blue-green bacterial blooms, which have taken off in the warm, shallow waters of Lake Erie since the mid-1990s consume oxygen, contributing to dead zones in the lake with almost no life, and produce toxins that can be lethal to pets and harmful to people.

Cyanobacteria is natural, but the growth of large blooms that foul municipal water intakes and make swimming and water sports inadvisable is linked to phosphorus from farm runoff and human sewage washed into the lake during heavy rains.

What’s different this year is the heavy rainfall the region received before summer, said Sandy Bihn, of Lake Erie Waterkeeper, an Ohio-based environmental group.

The wet spring delayed planting which means fertilizers weren’t applied in the usual time frame, which raises a question: Why is the level of phosphorus, a main ingredient in chemical fertilizers, so high?

Maumee Watershed

Bihn speculates that more farm animals packed into the same region — especially the large U.S. Midwest farm belt that drains into the lake — is a key contributor to the cyanobacteria problem.

“I would suggest that the answer is we keep increasing the number of (farm) animals, the amount of manure, and . . . that manure is ­running off and is a major ­component of the high levels of phosphorus we’re seeing this year,” she said.

“The phosphorus readings ­coming out of the Maumee River (which empties into Erie at ­Toledo, Ohio,) are very high and that’s usually the indicator they use for the size of the bloom,” said Bihn.

Last year’s bloom started early but was relatively small compared to past years, she said.
“We’ve seen some scum and some indication that the (blue-green) algae is coming,” she said. “So, it’s kind of on a wait-and-see mode.”

In Southwestern Ontario, including the Thames River valley, a number of projects are on the go to fight cyanobacteria in Erie by reducing the level of phosphorus flowing into Erie.

They include mimicking natural processes to hold and filter water in urban developments, slowing it down before it runs off, and ­improved winter field cover in rural areas to minimize nutrient runoff.