BonitaNews.com

Bloom washing ashore in Southwest Florida

By Julio Ochoa (Contact)

Sunday, July 22, 2007

http://www.bonitanews.com/news/2007/jul/22/bloom_washing_ashore_southwest_florida/

It’s not red tide. It’s not red drift algae. And it’s not anything that locals can blame on Lake Okeechobee.

“I’ve been here 40 years and I’ve never seen anything like it,” said Debra Hale, owner of Gulf Breeze Concessions, a hot dog stand at the Bonita Beach public access area. “That looks like sewer water.”

It could be one of two naturally occurring algae that have been menacing the Southwest Florida coast for the past few months.

If it looks like sewage is likely a form of algae called Lyngbya majuscula, said Rick Bartleson, a research scientist for the Sanibel-Captiva Conservation Foundation.

Some of the sewage-like algae has been washing up on Sanibel beaches too, Bartleson said.

But it could also be algae from a massive bloom off the coast called Trichodesmium, he said.

That bloom, which appears to be about 50 square miles in size, has been washing ashore in Southwest Florida from Collier County to Charlotte County for the past month.

Though the Florida Fish and Wildlife Research Institute classifies the Trichodesmium as non-toxic, Bartleson said he’s found evidence to the contrary.

Some studies confirm both forms of algae produce toxins. The production rate is very low, but it has been known to kill oysters, Bartleson said.

It’s possible the large bloom of Trichodesmium is responsible for the scores of dead scallop that washed ashore in Sanibel late last year and early this year, he said.

There is a form of Lyngbya in Australia that is so toxic, it’s called fireweed because it gives people severe rashes.

Nancy Conway said the bloom of slime she waded through off Bonita Beach gave her a sting.

The water off her beach home can be completely clear in the morning when the tide is high. But when the tide when out this week, the brown algae, which smells fishy, started washing ashore.

“At first we though they let the water out of Lake Okeechobee or something,” said Conway who has been coming down to Bonita Springs for 20 years.

“It’s completely different. We thought we best check it out before we wade through it.”

The Florida Fish and Wildlife Research Institute received its first report of the Trichodesmium on June 8 from Rookery Bay.

Since then, evidence of the bloom has shown up in its weekly tests.

The bloom is fairly common in the summer months, said Jeremy Lake, spokesman for FWRI.

When the algae is present the water can turn brown or green and get a bit chunky, Lake said.

“It could look like cereal that’s floated in milk for a couple of days when it’s heavily matted up in there,” he said. “But at this point, we’re nowhere near that level.”

Both forms of algae are naturally occurring and grow in on the surface of oceans throughout the world. But such a large bloom could be evidence of excess phosphorus and iron in the water, Bartleson said.

The chemicals enter the water from common fertilizers, the phosphate industry or cattle manure, he said.

Also, hundreds of tons of phosphorus entered the system after the 2005 hurricanes and is still being cycled and recycled, Bartleson said.

What’s odd is that the massive bloom is drifting so close to shore, he said.

“I haven’t heard of a Trichodesmium bloom like this so near shore,” Bartleson said. “I’ve been here 50 years and I think this is unusual.”

Since the algae started washing ashore in Bonita this week, Conway said she’s heard plenty of theories about what it is.

“Somebody told me it’s renourishing the sand,” she said. “But I don’t believe that either.”