Rare algae bloom near Sanibel sparks environmental concerns

The waters near Sanibel have turned murky due in part to a rare algae bloom called Margalefidinium polykrikoides, or rust tide, which has been recorded in Southwest Florida for only the second time. "The water looks a little murky. It caught our attention, but well, we don't know what's causing it," Lee County resident Mercedes Morales said in Spanish. Rick Bartleson, a researcher with the Sanibel-Captiva Conservation Foundation who has studied water quality for 50 years, said the bloom is a threat to Southwest Florida. "It is a bad thing for the environment," Bartleson said. This algae bloom depletes oxygen in water, suffocating marine animals and plants and creating conditions for other algae blooms to thrive. "That kills a lot of things that are at the bottom, in the sediments on the mangroves: animals invertebrates that can't swim to where there's more oxygen," Bartleson said. While researchers say eating fish that have consumed the algae is unlikely to make people sick, they caution that it is too early to determine whether other algae blooms will follow. "It doesn't have the same airborne human impacts as red tide, but anytime you see a species blooming in such high cell counts, we're definitely concerned about that," said Jason Pim with Calusa Waterkeeper. Pim advised people to avoid water showing signs of algae blooms. "'When in doubt, stay out' is kind of one of the rules of thumb," Pim said. Morales said she plans to follow that advice on her next fishing trip. "I'm not going to eat a single one, and I'll avoid going in the water for a while, too, until we know for sure what it might cause," she said in Spanish. Researchers noted that recent thunderstorms have contributed to the algae bloom, which they expect to persist for now. DOWNLOAD the free Gulf Coast News app for your latest news and alerts on breaking news, weather, sports, entertainment, and more on your phone or tablet. And check out the Very Local Gulf Coast app to stream news, entertainment and original programming on your TV.