LESS ALGAE IN FORECAST

Smaller blooms in Lake Erie

With beaches one of its retreats from the COVID-19 lockdown, Southwestern Ontario is catching a break in this summer of pandemic.

The forecast for beach- and water-fouling blue-green algae on Lake Erie is a positive one, spawning a patch that’s expected to be much smaller than 2019, U.S. researchers say.

“There will be some noticeable bloom out on Lake Erie this year. ... But much of the lake will be fine most of the time,” said Rick Stumpf, oceanographer at the United States National Oceanic and Atmospheric Administration (NOAA).

“This is much improvement over what we saw last year.”

Researchers from NOAA, Ohio State University and the Ohio Sea Grant research institute released the Lake Erie forecast in an online presentation Thursday, their ninth annual prediction.

The research team closely tracks phosphorus deposits into the lake year-round, a key driver of the growth of blue-green algae — whose scientific name is cyanobacteria — and uses several different models to predict the severity of the annual blooms.

The severity index is based on the amount of algae in the patch over time.

This summer, the Lake Erie bloom is expected to reach a moderate 4.5 in severity, but could come in anywhere from four to 5.5, Stumpf said.

Where the patch ends up in the lake this summer will depend on wind direction.

“A wind from the north will be better for Ontario,” Stumpf said.

Last summer’s algal bloom was a 7.3 on the researchers’ severity scale, more than double the rating on the 2018 bloom.

The largest, most severe Lake Erie blooms happened in 2011 and 2015, when the slimy green scourge reached a 10 and 10.5 in severity respectively. In 2011, the bloom blanketed a section of Lake Erie’s western basin nearly the size of Prince Edward Island.

The 2020 Lake Erie prediction, while better than last year, is still above the target set by Canada and the United States.

NOAA, the U.S. Environmental Protection Agency, Environment and Climate Change Canada and other partners have set a goal to get annual blooms below a three in severity.

The last time the Lake Erie bloom was below three was 2012.

While blue-green algae could crop up in other places, the western part of Lake Erie is typically the hardest hit by harmful blooms, Stumpf said.

In 2014, a particularly toxic one forced Toledo, Ohio, officials to shut down drinking-water intake valves. Regulators feared the toxin-producing cyanobacteria could be harmful to humans.

The algal patches — which consume oxygen from the lake, leading to dead zones — pose a threat to marine life and Lake Erie’s tourism sector.

Phosphorus, a nutrient found in human sewage, animal waste and chemical fertilizers, is a key culprit in blue-green algal growth on the lake. The nutrient runs off land into waterways, empties into the lake and feeds the algae in the summer.

Co-ordinated efforts to reduce phosphorus from entering waterways in the Great Lakes basin are underway on both sides of the border.

“Addressing nutrient loading and harmful algal blooms clearly demands an ‘all hands on deck’ approach,” Ohio Sea Grant director Christopher Winslow said in a statement.

“The expectation of a smaller bloom than 2019 is clearly something we should welcome. Nevertheless, we still have work to do.”

After cold temperatures in the lake in May and June, visible algae is expected to show up starting in mid- to late-july. The research team said high lake levels are not expected to have an effect on the size of the bloom.