Lake Erie, more specifically its western end, experienced a longer and more severe harmful algal bloom (HAB) season last year, according to the Ohio Environmental Council.
HABs are the result of nutrient pollution, most often from nitrogen and phosphorous, to bodies of water, and are extremely toxic to people and wildlife. These blooms typically occur in Lake Erie from July to October each year, and 2024’s bloom reached a severity index (SI) of 6.6, a number slightly higher than what was forecasted for the season and up 1.3 from 2023’s SI of 5.3.
Researchers at Bowling Green State University (BGSU) say climate change is one of the factors causing these algal blooms, and they can create problems for the economy and public health.
“It is estimated there are many billions of dollars of economic activity on the shore of the western end of Lake Erie in Ohio,” said Bob Midden, emeritus professor at BGSU.
“This activity is severely threatened when the water is this green muck that contains high concentrations of some of the most potent toxins that humans know,” he said.
Recreation, tourism and fishing in and surrounding Lake Erie are a major source of revenue for Ohio, and last year’s bloom was most concentrated between Monroe, Michigan and Port Clinton, Ohio. $10.7 billion – nearly 30% – of Ohio’s total tourism dollars are spent by visitors to Ohio’s Lake Erie region, according to the Great Lakes Commission.
Midden said the problem is not only in Lake Erie. Some of the state’s inland bodies of water, like Grand Lake Saint Marys State Park, also saw extreme economic deficits due to algal blooms.
“They estimate $160 million in tourism and recreation economic activity was lost in the summer of 2011 because of a massive, intense algal bloom there,” Midden said.
But the economy is not the only thing negatively affected by HABs. James Metcalf, associate professor at BGSU, said they are a threat to public health as well.
“The term ‘algal bloom’ is a misnomer because these organisms are closer to E. coli than they are to algae,” he said. “They are bacteria; they’re not even plants.”
Metcalf said exposure to toxins found in HABs can potentially cause illness or even death in people and animals. Microcystin is one of the toxins found in the blooms in Lake Erie.
“High enough doses of microcystin can cause death to occur in two hours, as the liver will dissolve,” he said. “Low doses over time increase a person’s risk of primary liver cancer.”
Metcalf said HABs often kill dogs, and animals in the water, like fish, “consume these organisms and the toxins are transferred into their flesh.”
He also said Lake Erie supplies 11 million people with drinking water. In 2014, residents of Toledo getting water from the city’s water treatment plants were told not to drink or bathe in the water due to high levels of poison present from HABs.
“The state of Ohio has decided it would be worthwhile to devote some money to reducing this problem,” Midden said.
Progress toward reducing HAB levels in Lake Erie has been made in the past, but it is unclear what changed in recent years, according to Metcalf. He said restoring Lake Erie will not be possible if people do not express concern over HABs.
“People should be concerned because we are making conditions such that we are destroying our own backyard,” he said. “It’s going to take people’s interest, money, political will and a drive.”
