When will SW Florida waters return to normal? Soon, scientists hope

An algal bloom turns ocean water to a murky brown color on Tuesday, October 2, 2018, at Vanderbilt Beach in Naples.

For months a toxic red tide algal bloom has plagued the shores of Southwest Florida, washing up dead sea animals and making it difficult for beachgoers to breathe. 

Recently a new type of bloom has appeared, turning the water a deep murky brown.

Now the question on everybody's mind is: When will the water return to normal?  

Discolored water has been reported at multiple locations, including Barefoot Beach, Seagate Beach and the Naples Pier, according to Naples' natural resources manager, Stephanie Molloy. Beachgoers on social media also reported a similar discoloration at Bonita Beach on Sunday.

But while red tide spells have ravaged Southwest Florida beaches and sea life for months, the discoloration is being caused by a bloom of a nontoxic diatom, called Cylindrotheca, Molloy said.

Previously:What's turning Southwest Florida's shores brown? It's not red tide

More:Murky waters at Naples Pier keep swimmers away

Florida Gulf Coast University marine sciences professor Michael Parsons said the diatom can grow "a lot faster" than the red tide organism, Karenia brevis, but he also said offshore winds could start to break up the bloom.

"The winds are coming out of the east-northeast, which should move the bloom offshore, so that will help," Parsons wrote in an email Tuesday afternoon. "These offshore winds will also help dissipate the bloom."

A dead fish lays on the shore on Tuesday, October 2, 2018, at Vanderbilt Beach in Naples.

Parsons also said diatom blooms typically last less than 30 days, and conditions are favorable for it to vanish even sooner.

"With continued offshore winds and the onset of dry season, I hope that the bloom will stay offshore, little runoff will occur due to reduction in rainfall, and the bloom will starve," he wrote.

Those factors will also help break up the remaining red tide, Parsons said, but there needs to be a cold front, too.

"Cold fronts, particularly strong ones that mix the water, will be needed to re-oxygenate the waters and break apart the red tide cells," he wrote.

The water on Sanibel Island’s Bowman’s Beach also has been darkly discolored by a bloom of another microorganism, a nontoxic dinoflagellate called Peridinium, said Sanibel-Captiva Conservation Foundation research scientist Rick Bartleson.

The diatom causing the discolored water in Collier and south Lee also can contribute to  poor oxygen levels, which can lead to fish kills, Parsons said.

Beachgoers stay out of the water, which has turned a murky brown color due to an algal bloom, on Tuesday, October 2, 2018, at Vanderbilt Beach in Naples.

More:Third species of algae, fueled by decomposing fish, is found blooming in Southwest Florida waters

Election 2018: Gov. Scott cancels Naples campaign event after red tide protesters confront him in Venice

In Collier the brown water started showing up last week and has been moving back and forth between Barefoot Beach and the Naples Pier, said Rhonda Watkins, a senior operations analyst with Collier County Pollution Control.

Jack Wert, Collier County’s tourism director, said the diatom hasn’t had an adverse effect on tourism, in part because it’s nontoxic and more isolated than red tide. However, the number of tourists in Collier declined in August due to red tide, and Wert said he is worried the trend could carry over into season.

“We are concerned that there could be longer-term negative effects because it seems like a lot of people don’t understand Florida geography,” he said. “So they see a story about red tide affecting the beaches in Clearwater and think that it affects the entire west coast, and that’s just not the case.”

Florida algae crisis:Collier had fewer visitors in August, in part due to red tide

Response to red tide:County plans tourism marketing for when coast is clear

Wert’s department plans to launch a public relations campaign later this month to let people know Southwest Florida’s beaches are clear and ready for tourists. The campaign will include social media posts, pictures and videos of the beaches, and real-time updates about beach conditions.

"We're monitoring the beaches on a daily basis and constantly posting that information on our website so people can see for themselves that the beaches are OK," Wert said.

Collier County reporter Patrick Riley and Fort Myers News-Press reporter Amy Bennett Williams contributed to this report.

Connect with the reporter at Lisa.Conley@naplesnews.com or on Twitter @LNConley.