Freshwater Futures

On a hot August weekend in 2014, nearly half a million residents of Toledo, Ohio, woke up to an alarming message: Do not drink or even touch your tap water. Lake Erie, Toledo’s main water supply, was fully contaminated by a harmful algae bloom toxin, microcystin. As boiling only increases the concentration of the toxin, residents had to rely on bottled water for drinking, pet care, washing, cooking, and brushing their teeth. Clean water, something most had taken for granted up until that point, was entirely inaccessible for three days.

The event became known as the Toledo Water Crisis, although it also impacted communities in Southeast Michigan and spread to Pelee Island, Ontario, a few weeks later. For many, the crisis shed light on how algal blooms can disrupt entire communities, threaten public health, strangle ecosystems, and dampen the recreational spirit so treasured by Great Lakes residents. 

Over a decade later, Berk Durutürk, a Ph.D. candidate at the School for Environment and Sustainability (SEAS) and a senior member of the University of Michigan’s Aquatic Biogeochemistry Lab, is continuing to push for a better understanding of algae blooms to help efforts to protect our Great Lakes.

“I want people to see that the Great Lakes are our future. They supply freshwater for millions of Americans and Canadians, and they play a crucial role in our lives,” he says.

Durutürk’s path to U-M stretches from Türkiye to Russia and, finally, to Ann Arbor. Initially drawn to freshwater lakes for their ability to act as natural vaults for Earth’s history, perfectly preserving our past in the sediment, he now focuses on protecting freshwater futures. 

“Lake Erie and Lake Superior are polar opposites,” Durutürk says. “Superior is so clear, so pristine—Erie is so contaminated it feels almost like a dystopia. You go to places like Kelley’s Island or Put-in-Bay, beautiful tourist destinations of Lake Erie, and you can’t even swim because the water is toxic.”

Durutürk explains that two nutrients are the heart of the problem: nitrogen and phosphorus. While both nutrients are perfectly natural on their own, human activities like using agricultural fertilizers, allowing sewage run-off, and dumping industrial waste have sent their levels soaring.

University of Michigan researchers, led by SEAS Professor and Michigan Sea Grant Director Silvia Newell at her Aquatic Biogeochemistry Lab, note that human actions have quadrupled the amount of “fixed” nitrogen cycling in our planet’s ecosystems over the past century. Historically, healthy lakes, such as Lake Superior, have always handled some nutrients, but the current nutrient load is more than many lakes can manage.

While algal bloom harms make the news when they impact people, natural ecosystems also experience intense harm as the blooms block sunlight that native aquatic plants and fish need to survive. When the blooms die and sink to the bottom of the lake, the ecological devastation continues as decomposition gobbles up oxygen, starving fish and other aquatic life. 

On a possibly less dire but deeply felt level, especially for those who grew up near the Great Lakes, scummy water is no place for a swim. This fact has the potential to upend the culture—and summer tourism dollars—of the Midwest. “Any sensible person will look at a murky green puddle and decide not to swim,” Durutürk says.

Excess nitrogen and phosphorus are magnified in shallow, fast-circulating lakes like Erie. “In summer, the winds churn everything up, temperature increases, and there’s lots of input. It’s a prime and ideal algae environment. Basically, that’s why Erie gets those wild green blooms every summer,” he said. 

As an opposing endpoint, Superior’s colder, deeper, less productive waters have only recently started showing coastal blooms. “If Superior is next, it will be a tragedy—these are completely different ecosystems, but both are at risk.”

To learn more about the trajectories of Lake Erie and Lake Superior, Durutürk traces the invisible movement of nitrogen and phosphorus isotopes through water and sediment incubations.

“We collect lake bottom sediment cores from carefully chosen sites on both lakes, then put them in controlled systems in the lab,” he explains. “We pump stable isotopic forms of nitrogen—tracer methods—so we can measure how the nitrogen transforms into different forms right before our eyes.”

For Lake Erie, the experiments follow nitrogen alone. For Lake Superior, both nitrogen and phosphorus are tracked, since nutrient limitations are part of Superior’s story. “The incubation runs for 72 hours, with samples every 24 hours. You end up with mountains of data—it’s a three-years-long marathon,” Durutürk says.

Durutürk’s preliminary findings prompt caution: “It’s not a perfect comparison, but if current patterns hold, Superior’s pristine reputation could start slipping,” he says.

For those living near or visiting the Great Lakes, Durutürk says public awareness is key. “We need more conscious industry and farmers—fertilizer and industrial runoff have always been a tremendous issue. But citizen scientists can help, too, especially through reporting.”

He encourages residents to report suspicious-looking algae—pea soup color, thick scum, paint-like slicks—to the Environmental Assistance Center of the Michigan Department of Environment, Great Lakes, and Energy (EGLE). “If you wouldn’t consider drinking it, don’t touch it! Reporting helps researchers track changes.”

More broadly, community is crucial. “In Türkiye, we all knew our neighbors, at least whereI grew up,” Durutürk recalled. “Unity, supporting each other, and staying aware of what’s happening is how we protect our shared treasures like The Great Lakes. If you lose hope, everything feels lost. But working together, reporting, supporting well-designed, collectively-decided, and sustainable policies—That adds up.”

Department of Environment, Great Lakes, and Energy Algal Bloom Information and Reporting.