Scientists believe a dry spring in Lake Erie’s western basin watershed will help keep the annual harmful algal bloom in check this summer and early autumn.
The bloom’s biomass is expected to rank 4.5 on a scale of 10 in terms of severity, according to Rick Stumpf, oceanographer with the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science. That is significantly smaller than the 2019 bloom, which was forecast at 7.5, subsequently emerging as a 7.3. The 2018 bloom rated just 3.8.
“It will be a possible range between 4 and 5.5,” Stumpf said. “While we are definitely better than last year we are definitely above the target, which means there will be a noticeable bloom on Lake Erie.”
The bright green bloom usually becomes visible in July and consists of massive swaths of cyanobacteria, a form of blue-green algae known to sometimes produce microcystin toxins which can be harmful to people and pets. The microcystin is the same toxin blamed for the Toledo water crisis during the 2014 bloom. That event garnered worldwide attention after it shut down the drinking water supply in Toledo area for almost three days.
Governments, universities assemble forecast data
The forecast number was determined after data from more than a dozen sources, including NOAA, U.S. Environmental Protection Agency, Heidelberg, Ohio State and North Carolina State universities, NASA, Ohio Sea Grant and universities of Toledo and Michigan, among others, was assembled and studied. A Lake Erie algal bloom forecast has been produced each year since 2002.
Stumpf said lowering bioavailable phosphorous (dissolved phosphorous) loading into the lake would reduce the blooms. However, even with less nutrients, weather is a consideration in the development of the blooms.
Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University, said a single rainfall event in May drained about the same amount of phosphorous from the watershed, sending it into the Maumee River, as the total of the prior two months.
“To talk about loads you have to talk about water first,” she said. “Since the early 2000s we’ve seen this continuous upward trend in flow. We’ve had some very intense rain events, some rainy years in terms of March through July stream flow. It seems like now we’re increasing the frequency of high flows which is going to be an added challenge.”
Stumpf said that while weather conditions will dictate whether HABs are concentrated on the surface as a thick scum, there will be plenty of opportunity this year for people to get on the water and enjoy the resource.
“Definitely use Lake Erie,” he said. “This is an improvement over what we saw last year. I will say much of the lake will be fine most of the time. Blooms are mostly in the Western Basin, but even there they move around a lot with the wind.”
HABs can be present but unseen when winds are strong and wave action in the lake disperses the algae throughout the water column. HABs become most visible when the algae moves to the surface when the lake is calm. Prevailing winds also move the bloom, pushing it in the wind’s direction.
“There will be areas of high concentration. So I can’t emphasize enough, the bloom does produce some toxins, so please stay out of the scum,” Stumpf said. “If you are in Ohio or Michigan, you’re going to want southwest winds. If you’re in Ontario, you’re going to prefer winds out of the north.”
Stumpf said a bloom in the downtown Toledo area on the Maumee River developed recentlyand is especially visible due to a low water flow on the river and high lake levels penning the river in.
“In this case it appears to be developing locally,” he said. “The water is pretty much stopping in downtown Toledo and so the phosphorous is concentrating in that area. We think what’s happening is it’s very still in that area and cyanobacteria like warm water and also a very still flow. So it’s an anomaly due to the combination of low flow and high lake level.”
Chris Winslow, director of Ohio Sea Grant and OSU’s Stone Lab, said scientists have recently sampled that Toledo bloom to find out more.
Stumpf said anyone interested in keeping tabs on Lake Erie’s 2020 bloom can do so with NOAA’s HABs tracker.
Sources of phosphorous pollution still varied
During the last decade, agriculture operations in the Lake Erie Western Basin watershed have been pinpointed as major contributors of nutrients entering the lake – and feeding HABs – with the Maumee River being the main avenue.
“Last year one of the things we learned is that the ways in which farmers apply their fertilizer and manure can potentially have a 30 percent effect on dissolved reactive phosphorous,” said Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University. “That means that an awful lot of that load which comes out, that 70 percent is reflecting some number of past years, from more than the one year we’re measuring.”
Nutrients which remain in soil from previous years applications are often referred to as legacy nutrients. While researchers are still grappling with the problem of how to deal with pre-existing nutrients, they are homing in on how to deal with current nutrients used in farming.
“There are more and more nutrients management plans going out. I would expect that big chunk, you can call it legacy, it’s going to take a bit of time,” Johnson said.
Winslow emphasized the watershed land area which must be managed for nutrients is huge.
“Know that you’re talking about millions and millions of acres in the Western Basin. In my experience in working with producers, there is clearly an uptick in best management practices in the watershed,” he said.
BMPs are a group of farm management practices known to reduce phosphorous runoff and mitigate nutrients pollution.
While runoff from commercially applied fertilizer products and manure from animal farming operations are considered major feeders of HABs, there are still other sources.
Many communities whose waters are Lake Erie tributaries still suffer combined sewer overflow events when they’re hit with heavy rains, which overwhelm sewage treatment plants and municipal drainage systems. In addition to CSOs, failing private septic systems are a source of algae-feeding nutrients as well as fertilizer from golf courses and homes throughout the region.
New tech to see citizen scientists help monitor bloom toxins
A NOAA-funded project currently in the works will help pr
oject the toxicity of algal blooms by linking members of the public with researchers, according to Timothy Davis, associate professor in the biological sciences department at Bowling Green State University.
He said cyanobacteria density doesn’t necessarily corelate with toxicity. Two single-day sample studies in 2018 and 2019, involving a total of 275 near-simultaneous samplings in Western Basin blooms, proved the variability. Researchers then became interested in developing a method to forecast toxicity in addition to bloom severity.
“The data we were able to collect showed that while the blooms were extensive, we see that toxicity varies, and they don’t always align with cyanobacteria density,” he said.
As the group discussed the power of massive sample-taking in single three-hour windows, they discussed how to expand toxins data collection in Lake Erie.
“We thought it would be really neat to involve citizen-scientists in this effort to collect more data,” Davis said. “So we got together and we’re linking a new portable toxin detection technology with researcher and citizen scientist water collection to try to get a more seasonal, better resolution of cyanobacteria toxin in western Lake Erie.”
The MBio detection system allows a person to extract toxins from a water sample and apply the concentration to a small cartridge. The device will then examine the toxins and display a report on a tablet or laptop. The data could then be uploaded, via an app currently being developed, to a database allowing researchers to better inform toxin forecasts.
The project will include data input from water plant operators, charter captains, beach managers and others, Davis said. The new technology was just used in the field in response to a Sandusky Bay resident who expressed concerns about children swimming in what appeared to be water with a significant algae scum. Davis said he received the resident’s email in the morning.
“I was able to send a graduate student to the site where he was able to collect a sample using this technology, extracting and analyzing it on-site. By noon, we had on-the-spot data,” he said.
The cost of the portable field equipment is about $5,200 per unit.
Read more on toxic algae on Great Lakes Now:
Featured image: Toxic algae blooms around the Great Lakes in the summer. (Great Lakes Now Episode 1013)