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Toxic algae blooms in Lake Erie raise health concerns

Published: 16 Sep. 2025, 08:00

On the shore of Lake Erie’s western basin, the remains of Lyngbya are drifting in the water on Aug. 13. [JEONG EUN-HYE]

TOLEDO, Ohio — Toxic algae blooms are turning Lake Erie green, choking its shoreline with foul-smelling sludge and leaving residents battling health problems as scientists warn the outbreaks are growing longer and more dangerous with climate change.

The western shore of Lake Erie rippled under the summer sun on Aug. 13 with waves tinted green. The discoloration came from a surge of Microcystis, a harmful cyanobacteria more commonly known as blue-green algae.

Closer to shore, black clumps drifted along the current like strands of hair — they were the remains of Lyngbya, another species of cyanobacteria.

Once common in tropical and subtropical waters, it has begun to appear in temperate regions as the climate warms. When it decays, Lyngbya releases toxins that cause foul odors, skin irritation, respiratory illness and animal deaths.

Remains of Lyngbya [JEONG EUN-HYE]

Ken Sabin, 75, who spent his life working on boats on Lake Erie, said he has felt the effects. He recovered from childhood pneumonia without lasting issues, but his lung condition deteriorated after the massive algae bloom in 2014, leaving him dependent on a respirator at home.

Lake Erie, which is about one-quarter the size of Korea at 26,720 square kilometers (10,320 square miles), experiences severe blooms in its shallow western basin every summer as farm and urban runoff flows in from nearby rivers. In 2014, toxins from the algae entered the public water system, leaving some 500,000 residents unable to use tap water.

Rising water temperatures have worsened the problem. Harmful algae now appear earlier each year and persist for longer stretches. This spring, scientists detected toxins as early as April.

Researchers working at the site said that cyanobacteria that release toxins are evolving with climate change.

While Microcystis remains the most common species, Lyngbya has gained ground, and Dolichospermum — formerly known as Anabaena — has also begun to appear.

Thomas Bridgeman, an ecology professor at the University of Toledo and director of the UToledo Lake Erie Center, explained that Dolichospermum is more resilient than other species, able to survive in both hot and cold conditions, which allows its blooms to persist longer. He noted that it also generates a separate class of toxins that heighten risks to public health.

Researchers have focused on a potential link between algae and respiratory illness. Since the mid-2010s, when severe blooms began, the Lake Erie region has been called the "Ohio-Erie Asthma Belt" for its unusually high asthma rates.

David Kennedy, a professor of medicine at the University of Toledo, is studying residents to determine how aerosolized algae toxins affect patients with preexisting conditions. He said researchers have not yet proven the health risks of airborne algae toxins, but emphasized that people are falling ill and that identifying the link is essential to addressing the problem.

David Kennedy, a professor of medicine at the University of Toledo, points to a drainage outlet where pollutants from nearby farmland flow into the lake on Aug. 13 on the shore of Lake Erie’s western basin in Toledo, Ohio. [JEONG EUN-HYE]

Globally, harmful algal blooms, or HABs, have also increased in frequency and intensity.

Between the 2000s and 2010s, blooms in lakes across Asia and Africa grew by about 44 percent. Europe and the United States have also struggled to contain them despite efforts to reduce pollution, as warming waters fuel continued outbreaks.

The U.S. suffers an estimated $2.2 billion in annual economic losses from HABs, including costs for water treatment, health care and damage to fisheries.

Ohio has spent $2.3 billion since 2011 on wastewater treatment and drinking water improvements, and has invested another $100 million to help farmers cut fertilizer runoff.

In 2020, the state began a 10-year project to spend more than $100 million annually to reduce nitrogen and phosphorus discharge from farmland. However, Lake Erie has shown little improvement so far.

Scientists say more long-term research is needed.

Since 2015, the U.S. government has spent over $37 million on studies into cyanobacteria.

Lee Ji-young, a professor at Ohio State University’s Department of Food Science and Technology, is examining links between algae toxins and conditions such as Alzheimer’s disease. She stressed that evaluating the health risks of algae toxins requires looking at multiple factors, including inhalation, consumption of contaminated fish or crops and the duration of exposure. She added that drawing firm scientific conclusions will require a large amount of data.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY JEONG EUN-HYE [[email protected]]