Despite searing heat and heavy showers at various times this month, the National Oceanic and Atmospheric Administration is sticking to its prediction that western Lake Erie’s algal bloom this summer will be as small as last year’s and relatively mild overall.
“The bloom will be similar in size to 2020, making this the first time in more than a dozen years that relatively mild blooms will have occurred in consecutive summers,” NOAA said in a bulletin released Wednesday after the conclusion of an annual event in which several government and university researchers explained the science behind the forecast.
The forecast is an ensemble of work that includes data collected and analyzed by NOAA and its partner universities in the western Lake Erie region, including Heidelberg University’s National Center for Water Quality Research, which has been tracking algae-forming phosphorus in water samples since 1974. Heidelberg’s sampling set is the Great Lakes region’s longest continuing set of such data.
The final prediction is generated by comparing the NOAA-led model with separate ones from the University of Michigan, Stanford University, and the Washington-based Carnegie Institution for Science. Researchers from North Carolina State University, the University of Toledo, Ohio State University, and LimnoTech also contribute.
This year’s forecast is for a bloom with a severity index of only 3 on a scale of 1 to 10, with 10 being the highest.
The scale was developed years ago when it was assumed there would never be a bloom larger and more intense than the one in the summer of 2011. But that one was surpassed in 2015, which scientists classified as a 10.5.
This year’s forecast has a plus-or-minus variance with a potential low of a 2 to a high of 4.5 on that scale.
“We had a little bit of rain in March, a very, very dry April and spotty thunderstorms since then,” said Laura Johnson, the Heidelberg water research center’s director.
The forecasts — which have become more accurate each year as more is learned about the science of developing them — are important to water-treatment plant operators, charter fishing-boat captains, other tourist-related businesses, and others that depend on Lake Erie water quality.
The severity index is based on the biomass of a bloom over a sustained period.
It is not sophisticated enough yet to predict toxin levels weeks in advance, but that is the ultimate goal, according Rick Stumpf, an oceanographer from NOAA’s National Centers for Coastal Ocean Science in Maryland who helped develop and has overseen the forecasting program since its inception several years ago.
Similar modeling is being considered for other algae-prone parts of the Great Lakes region, such as Saginaw Bay and Green Bay, Mr. Stumpf said.
“There's a lot of variability and that comes back to wind conditions,” Mr. Stumpf said. “Unfortunately, we can't predict those.”
Although encouraged by what the DeWine administration is trying to do for Lake Erie under its H2Ohio program, which promotes more wetlands and better farming practices, Mr. Stumpf and Ms. Johnson cautioned against giving the governor’s program too much credit for this year’s more modest algae forecast.
Water samples drawn by Heidelberg show phosphorus and nitrogen concentrations remain higher than they now should be under an agreement signed among Ohio, Michigan, and Ontario years ago to reduce those inputs 40 percent by 2025.
Most of those fertilizers come from farm runoff.
The lower flow doesn’t mean agriculture has done its job yet, Ms. Stump and Ms. Johnson said — It simply means there wasn’t as much rain in March and April as in years past.
“If we had already met the target, we would have virtually no bloom this year,” Mr. Stumpf said. “It's a result of lower flow, not a reduction of nutrients going into the water.”
The region appears to be getting another reprieve because of rain’s timing. Efforts to control agricultural runoff must continue, he said.
“Until we begin to see reductions in the concentration of phosphorus, the next year with above-average rainfall will have a more severe bloom,” Mr. Stumpf said.
Ms. Johnson said the region’s water flow into the Maumee River and other western Lake Erie tributaries this past spring hasn’t been this low since the spring of 2012, which turned out to be one of the Great Lakes region’s most notable drought years.
The region is not in a drought now, nor is it expected to be in one this year because of rainfall that came in June and is expected to continue into July.
Climate scientists have said the Great Lakes region and the rest of the Midwest is second only to New England in terms of precipitation increases since the 1960s, and they have said this region can expect more frequent and intense storms as the effects of climate change become more acute.
But for purposes of predicting summer algal blooms, scientists are most concerned about what falls and when between March 1 and July 31, especially on the season’s front end. The frequency and intensity of storms in March and April — not just the volume of water — are major factors.
Ms. Johnson also said that research from the 2019 algae season shows that farm operators can indeed make a big difference with more targeted use of manure and other fertilizers: at the right place, the right time, and in the right amounts.
“That nutrient management is really going to be key,” Ms. Johnson said. “I'm really hopeful with H2Ohio. I think once we get that going, we're going to see some effects.”
Regardless how much green scum is present, it’s important to stay away from it and to keep dogs and other pets away from it. Several dogs are known to have died from the algal toxin produced in Lake Erie and its tributaries.
“Keep dogs out of the water,” Mr. Stumpf said. “It's quite dangerous for dogs. They don't need to ingest this stuff.”
NOAA tracks the bloom at different altitudes to complement research scientists do on the surface level throughout the summer.
It now uses high-quality satellite imagery from both of the European Union’s Copernicus Sentinel-3 satellites, which were designed to detect blooms in large lakes and estuaries.
First Published June 30, 2021, 2:29 p.m.
