NewsLocal NewsLee County


Smelly, nutrient fed algae mats return to Matlacha and Pine Island

Posted at 3:57 PM, May 19, 2023
and last updated 2023-05-19 18:49:29-04

MATLACHA, Fla. — Matlacha and Pine Island are seeing the return of their yearly visitor. It’s not a tourist, but instead, algae lining the coastline.

Not only does it look bad, but it smells bad, like rotten eggs.

These are all Dapis algae, a type of blue-green algae that has been hanging out around Pine Island for about a week or two now. This has been a yearly occurrence, according to Sanibel Captiva Conservation Foundation, but this year is particularly bad.

“I used to go up there fishing with my dad as a kid, it wasn’t anything like that,” said SCCF Research Scientist Dr. Rick Bartleson.

Dr. Bartleson adds that Matlacha and Pine Island have had these algae outbreaks since 2006. And not only does it look gross...

“In some places, it smells,” said Matlacha resident Mike Zazao. “It doesn’t smell for us back here, just we have a strong cross breeze, but it is not nice out here sometimes.”

Zazao says this happens every time the weather warms up.

“When the sun comes out, we get the mess that we get,” said Zazao.

Dr. Barlteson says the problem is nutrients getting stuck in Matlacha Pass from all over the place.

“Peace River has a phosphorus mine in its watershed,” said Dr. Bartleson. “The Caloosahatchee has Okeechobee water in its watershed. So, we are adding nutrients from the north to the south. From septic tanks along Pine Island Sound, Cape Coral, north of the Matlacha bridges, still on septic.”

And these continued algae outbreaks are leading to fish kills and loss of seagrass. In fact, Matlacha Pass has lost about 90% of its seagrass over the last 10 years according to South Florida Water Management. As for the fish kills, the animals that live in the mud can’t escape the anoxic water.

“It’s bad for the whole ecosystem because a lot of the animals that die from lack of oxygen are what feed the fish,” said Dr. Bartleson.

It isn’t just bad to sea critters, but it also could spell trouble if ingested.

“If they have the secondary metabolites that affect other bacteria then you don’t want those to be in your stomach or your dog's stomach, because your stomach has a lot of good bacteria that you don’t want to go away,” said Dr. Bartleson.

The mats could also feed harmful algal blooms.

“They are a rich source of nutrients for other types of algae as they decompose. So, they are full of other kinds of algae that might have cyanotoxins or HAB (harmful algal bloom) toxins.”

Despite how gross these algae mats look, experts tell Fox 4 there are no airborne toxins produced by the algae mat that are harmful to humans, despite the smell.