Just days after residents of Toledo, Ohio were told to avoid the tap because toxic algae blooms in Lake Erie had contaminated the water supply with mycrocystin that water treatment stations can’t deal with, Florida is facing its own algal menace. Scientists at the Optical Oceanography Laboratory at the University of South Florida (USF) have spotted an enormous algae bloom bigger than Rhode Island threatening Florida’s west coast and killing marine life along the way.

Algae Bloom

Red tides are dangerous for people with respiratory conditions

The name Red Tide is a bit of a misnomer since tidal forces aren’t actually involved, but a harmful algal blooms in the Gulf of Mexico are caused by a tiny marine algae called Karenia brevis that’s always present but typically in very small amounts. When the concentration swells it produces toxins that color the water red or brown and can poison marine like in addition to depleting dissolved oxygen (which marine life needs to breathe). Severe red tides are also dangerous for people with respiratory conditions who live in coastal towns, and can be an irritant for everyone else. Contaminated seafood occasionally makes it all the way to the dinner table, making people extremely ill.

Climate change makes algal blooms more frequent and severe

It would be easy to draw a strong connection between the two events, but the Lake Erie blooms were caused by agricultural pollution, while the presence of Karenia brevis in the Gulf of Mexico and the occasional red tide are natural phenomena being exacerbated by climate change. Both can be connected to human activity, but one in a very direct way (Ohio is already planning new regulations on fertilizer use) and the other maddeningly indirect. But the connection between climate change and more frequent harmful algal blooms has been documented for years. Since algae benefit from higher water temperatures, this has been one of the easier predictions for scientists to make (though timing, as in finance, is a lot more difficult).

Unfortunately for Ohio those regulations may come too late. OSU postdoctoral scholar Timothy Otten has found that once cyanobacteria take hold in a lake it’s extremely difficult to get them out.

Cyanobacteria are basically the cockroaches of the aquatic world,” said Otten. “They’re the uninvited guest that just won’t leave.”