Algae swirling on the Gulf Coast brings a stink near Matlacha

Algae swirling in the Gulf Coast is bringing a smelly odor to the air.

It’s happening around the waters of Matlacha.

“It’s almost a matted, matted surface that resembles a mud flat, but the colors are quite vibrant. And you can go from olives to Browns to cream colors, and then whites and sometimes even a little bit of orange mixed,” said Calusa Waterkeeper Capt.Codty Pierce. “When you smell it, you really smell a very heavy sulfur smell like rotten eggs. Sometimes it even smells like sewage.”

It floats up from the bottom of a water body in big floating patches and can pile up on a shoreline.

“I would say that its type of filamentous algae, perhaps maybe even dapis,” Pierce said.

The only way to know for sure exactly what it is, is to put it under a microscope.

“this is a cyanobacteria filamentous cyanobacteria we call dapis,” said Rick Bartleson, a research scientist with the Sanibel-Captive Conservation Foundation.  

Dapis feed off phosphorus and iron in the environment.

Bartleson has seen it before.

“Since 2006, when I started working here,” he said.

“The algae itself doesn’t produce toxins that would affect us, if we’re touching it or looking at it,” Bartleson said.

But, he warned people should keep their dogs away from it.

While it’s not a big problem now, how it breaks down matters, if it decomposes while wet.

“The sulfur bacteria will produce the hydrogen sulfide, and then some of that hydrogen sulfide will be oxidized to sulfur dioxide. And then that both of those are toxic to breathe in,” Bartleson said.

It’s what causes the smell, but Bartleson said, on a windy day, the hydrogen sulfide level is usually not high enough to be a problem.

The Dapis could be worse this year due to the hurricane as the storm carried nutrients from land into the waters.