Toxic algae blooms are lasting longer in Lake Erie − why that's a worry for people and pets
Federal scientists released their annual forecast for Lake Erie’s harmful algal blooms on June 26, 2025, and they expect a mild to moderate season. However, anyone who comes in contact with the blooms can face health risks, and it’s worth remembering that 2014, when toxins from algae blooms contaminated the water supply in Toledo, Ohio, was considered a moderate year, too.
We asked Gregory J. Dick, who leads the Cooperative Institute for Great Lakes Research, a federally funded center at the University of Michigan that studies harmful algal blooms among other Great Lakes issues, why they’re such a concern.
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Today, agriculture is the main source of excess nutrients from chemical fertilizer or manure applied to farm fields to grow crops. Rainstorms wash these nutrients into streams and rivers that deliver them to lakes and coastal areas, where they fertilize algal blooms. In the U.S., most of these nutrients come from industrial-scale corn production, which is largely used as animal feed or to produce ethanol for gasoline.
Climate change also exacerbates the problem in two ways. First, cyanobacteria grow faster at higher temperatures. Second, climate-driven increases in precipitation, especially large storms, cause more nutrient runoff that has led to record-setting blooms.
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Harmful algal blooms are unsightly and smelly, making them a concern for recreation, property values and businesses. They can disrupt food webs and harm aquatic life, though a recent study suggested that their effects on the Lake Erie food web so far are not substantial.
But the biggest impact is from the toxins these algae produce that are harmful to humans and lethal to pets.
The toxins can cause acute health problems such as gastrointestinal symptoms, headache, fever and skin irritation. Dogs can die from ingesting lake water with harmful algal blooms. Emerging science suggests that long-term exposure to harmful algal blooms, for example over months or years, can cause or exacerbate chronic respiratory, cardiovascular and gastrointestinal problems and may be linked to liver cancers, kidney disease and neurological issues.
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https://theconversation.com/toxic-algae-blooms-are-lasting-longer-in-lake-erie-why-thats-a-worry-for-people-and-pets-259954