ST. JAMES CITY, Fla. — Floating gunk is causing concern for residents of St. James City. They want to know what the substance is and what’s causing it.

“It comes in in the afternoon, typically on the canal…and it just kinda is not there in the morning when we come back in,” Rachel Milmont said. “It doesn’t smell anything, not making us cough; it’s just there.”

We got a sample and took it over to Dr. Barry Rosen at FGCU’s Water School. 

“It’s basically a mass of blue-green algae that’s come up. It’s not considered a bloom because it’s just material that comes up off the bottom,” he explained. “If it gets too much sun, it can start to bleach a little bit and that whiteness could be from too much sun or something else I didn’t see in this sample.”

The reason it comes in more in the afternoon is simple, according to Rosen.

“These clumps, they produce oxygen, all Cyanobacteria produce oxygen, and when they do that they trap some of the gas and that oxygen lifts these clumps up later in the day because they’ve been photosynthesizing long enough to pull themselves off the bottom,” he said.

Thankfully Dr. Rosen said the sample we brought in isn’t toxic. It won’t make you sick unless you decide to drink from the canal.