Saharan dust may impact SWFL coastal waters

A gigantic dust column from Africa’s Sahara Desert has traveled thousands of miles and will eventually settle over the U.S.

The dust is so thick it can be seen in satellite images, and once it reaches Southwest Florida, it may impact water quality.

Experts say it’s too soon to tell if we’ll have another bad red tide season. As of now, we’ll have to wait and see.

You wouldn’t know it by looking at Bill Crossman’s boat now, but two days ago, while on board a couple miles out from Wiggins Pass, “we hit what looked like sawdust or pollen on the water and then we hit a line of … it looked almost like an oil slick.”

Crossman said it turned his boat brown.

“We tried the regular boat wash and stuff, it didn’t even touch it. Just had to scrub, and we ended up with using a citric cleaner to get it off.”

He isn’t alone. Christopher Mosteiro saw something similar while heading out of Big Carlos Pass.

“Saw this reddish tint on the top of the water, pretty sporadically, about three miles out,” he said.

After sampling, it turned out to be “Trichodesmium,” or sea sawdust.

“Now the reports are coming in more frequently starting Saturday, so people are reporting seeing a couple of miles of this stuff as they’re heading west into the Gulf,” said John Cassani, Calusa Waterkeeper.

Iron fuels it, which can also come from Saharan dust.

“When Trichodesmium grows, it actually can make fertilizer. It can take nitrogen gas out of the air and turn it into nitrogen fertilizer, basically organic nitrogen that we think then feeds red tide,” said Dr. Mike Parsons, professor of marine science at The Water School at FGCU.

“We typically look for a Trichodesmium bloom before there’s a red tide bloom, and that red tide bloom tends to happen at the end of September or early October,” Parsons said.

“When I saw the amount that was out there, it’s a real concern for me,” Crossman said. “It’s impacted the economy here, the fishing industry, everything in this part of Florida for the last couple of years. Yes, I’m concerned.”

Cassani said Trichodesmium has the potential to produce toxins. Although not enough is known about inhaling it, Cassani said it’s best to not sit in the middle of one of these blooms.