Across the globe from Lake Erie, one of the world’s largest lakes is also troubled with toxic algae, and its situation could give scientists information for how to handle harmful algal blooms on Lake Erie in the future.
For the past two years, researchers from
Bowling Green State University and other international institutions have traveled to
Lake Victoria in Africa to study its harmful algal blooms.
What they found were some similarities to Lake Erie, including a bay comparable to Sandusky Bay, as well as data that can help the people living along the lake in Kenya be better informed about toxin levels that could harm people, pets, and livestock, says
George Bullerjahn, Ph.D., Emeritus Professor of Biological Sciences and Director of the
Great Lakes Center for Fresh Waters and Human Health at BGSU.
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For the past two years, researchers from Bowling Green State University and other international institutions have traveled to Lake Victoria in Africa to study its harmful algal blooms. “Lake Erie can provide some information on what makes a bloom toxic, but it is always a two-way street,” he says. “(The Kenyan researchers) know so much more about Lake Victoria and the activity around it. It’s really a powerful partnership that I look forward to continuing.”
Lake Victoria is the second-largest freshwater lake in the world, smaller only than Lake Superior. It borders Kenya, Uganda, and Tanzania.
Since the early 2000s, toxic algae, which are cyanobacteria, have bloomed on Lake Erie during the summer and often linger into fall. Cyanobacteria produces toxins that can sicken animals and people, and in 2014, it
shuttered the city of Toledo’s water treatment plant for multiple days.
Tracking the toxins on Lake Erie, Lake Victoria
The research team of BGSU faculty, Kenyan researchers and graduate students from colleges and universities around the United States and Canada sampled water around Lake Victoria last summer and during summer 2022. They worked with the
Kenya Marine and Fisheries Research Institute and
Kisii University.
The research was funded by a
National Science Foundation grant of nearly $400,000.
“We look at two very different lakes, Lake Erie and Lake Victoria, and do a nice comparative study of the cyanobacteria that make these toxins,” Bullerjahn says.
On Lake Erie, the harmful algal blooms are the cyanobacteria that produce the toxin microcystin. Although the team found low levels of microcystin in Lake Victoria, they were surprised to find higher levels of the toxin cylindrospermopsin, also produced by cyanobacteria.
The team hadn’t been looking for this toxin, so it provided new and valuable information for those living around the lake, Bullerjahn says. The researchers traced it to a source near the mouth of a river in a more populated area.
“They don’t have water treatment like we do,” he says. “They let the water settle out, and they wash with it and drink it. This is a potential threat, and we informed the authorities there they should be looking for this particular toxin. I think we’ve provided a lot of good information for the local authorities in collaboration with the Kenyan Marine Fisheries Research Institute.”
Research into the Lake Erie blooms over the past 20 years that the team has shared with Kenyan scientists also gives them some insight into what causes blooms here, how they change over time and when they start producing and releasing toxins, Bullerjahn says. This could give them insight into what to monitor on Lake Victoria.
Other researchers on the trip studied fish to get an idea of whether the toxins were moving up the food chain. They learned that is not the case with fish.
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Although Lake Victoria is located on the equator, it is 3,800 feet above sea level and maintains a temperature of around 82 degrees all year, Bullerjahn says. That’s similar to summer days on Lake Erie. The Nile perch, an invasive species that can reach 100 pounds and is a major source of food for locals, did not have any higher levels of algal toxin than small fish that were sampled. This research was led
by Ken Drouillard, Professor of Biology at the University of Windsor, in Ontario.
“The fish are actually better than the ones in Lake Erie,” Bullerjahn says. “We found out the sources of protein, the fish, were actually good to eat. So that was nice to be able to tell them that.”
Similarities to Lake Erie, looking to the future
Although Lake Victoria is located on the equator, it is 3,800 feet above sea level and maintains a temperature of around 82 degrees all year, Bullerjahn says. That’s similar to summer days on Lake Erie.
“It never freezes,” he says of Lake Victoria. “Studying the harmful algal bloom in Lake Victoria as sort of a glimpse to what Lake Erie could be in 20 to 30 years.”
Since 1980, there has been a 70-percent loss of ice mass on Lake Erie. During many winters in recent years, the lake no longer freezes.
“We know we’re heading toward an ice-free future,” he says. “That’s the reality.”
It’s possible that as the lake continues to warm through climate change, it might begin seeing the same cyanobacteria the team has found on Lake Victoria. If that’s the case, having data for Lake Victoria will help scientists address how to handle that bacteria.
Lake Victoria also has an area that is comparable to Lake Erie’s Sandusky Bay, called the Winam Gulf, located in the northeast corner of Lake Victoria. It extends about 50 miles and is shallow and is a similar system to Sandusky Bay, he says.
Bullerjahn and BGSU researchers have studied Sandusky Bay for more than a decade, so the data recovered between the two different bodies of water could provide important information in the future.
“Water flow in Sandusky Bay is not a raging torrent heading out into the lake,” he says. “It can be kind of a stagnant area. That’s kind of what the Winam Gulf is like.”
There is an island in the Winam Gulf where strong currents often created dangerous situations for boaters attempting to get there. A causeway to the island was built, which blocked the currents and somewhat stagnated the water, he says.
The toxic algae grew worse. The causeway was then replaced with a bridge, which allowed water to flow freely again, and the blooms in that area decreased in severity.
The island reminds him somewhat of Johnson’s Island in the Sandusky Bay, which is accessed by a causeway and bridge.
“There are some parallels there that are so neat,” Bullerjahn says. “If you can improve water flow, you can improve water quality.”
What’s next?
Bullerjahn and some of the team are returning to Lake Victoria for a short trip early next year to take more samples in areas of concern. The goal is to see if there are any changes when samples are taken at a different time of year.
He hopes the researchers can obtain more funding to continue the research and partnership.
“It was very rewarding to see a really diverse team of folks working together effectively and really relying on one another’s experience and expertise to get things done,” he says. “The Kenyan hosts were so tremendous.
“It was a tremendous cultural experience for the students who got to see what it was like to work in a very different environment.”