Algae is blooming across state waterways and up the St. Johns River, and toxicity levels are extremely high, test results released by the Riverkeeper show.
Test results show toxin levels are more than 100 times higher than what's recommended for recreational exposure.
"I was surprised at how high they were," said Dr. Quinton White, of Jacksonville University's Marine Science Research Institute.
Just because you can't always see the slime doesn't mean it's not there. That's because it's prevalent under the surface.
"It's a long-term toxin. That's the trouble," White said. "People get in it, get exposed to it, think, 'Oh, I'm fine.' It's actually toxic to the liver, so it may be a much longer time before you see any kind of results."
Exposure to the algae can also cause respiratory problems, which is concerning to the JU rowing team, which is prepping for a regatta this weekend.
"We're definitely breathing hard out on the river, so we don't want to chance anything with our athletes," rowing director Jim Mitchell said.
The algae outbreak is caused by warm water coupled with excess nutrient-pollution.
One of the reasons the river is turning up green is people mow their grass and let the clippings go into the storm drains, which runs off into the river.
"Jacksonville needs to take care of its own backyard," White said. "People can do their part by limiting fertilizer, fixing leaking septic tanks, watching how much they're watering, being a good steward of their resources."
"This is the place where we work and we play, and so we want to see a healthy river, especially with how much it means to the city," Mitchell said. "And so we see the dolphins every day and we don't want to see any negative impact that way."