Particularly strong, long-lived red tide still enveloping region

Chad Gillis
The News-Press

Ann and David Williams strolled along Bunche Beach on Tuesday shortly after leaving Sanibel because red tide conditions there were too much for the retired couple. 

"We went to Fort Myers Beach last night, and there's still fish on the beach, and it smells," Ann Williams said while coughing. 

The English couple has lived here part-time for about 30 years and agreed this is the worst red tide they've seen.

Images from Bunche Beach and the Sanibel Causeway. A suspected red tide outbreak is ravaging the marine life in Southwest Florida.

They know the red tide basics: that it occurs naturally at background levels, and that nutrients from human activities can feed the blooms. 

They know about the fish, sea turtle and manatee kills. 

They know what a bloom can do to the local economy, but still they have questions.

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 "What no one is telling is me why," Ann Williams said. "I need to know. Why is it so strong? And why is it happening now?"

This red tide has been particularly strong, the strongest since at least the 2005-06 outbreak. 

It's also long-lived. 

Historically, experts say, red tides appeared in the late summer or fall and disappeared soon after. 

And they weren't recorded every year. 

So why has this red tide been unlike others? Why are red tide counts during the summer literally off the measuring charts? 

"It’s not an easy thing to explain, and it’s not a cut-and-dry answer," said Michelle Kerr, spokeswoman for the Florida Fish and Wildlife Conservation Commission. "Red tide relies on a variety of different factors, kind of like a perfect storm. It’s very dependent on the strength and direction of winds and currents, and red tide can also feed off nutrients and runoff from land."

The bloom comes on the heels of the wettest wet season the South Florida Water Management District has ever recorded. 

Heavy rains last summer were capped off by Hurricane Irma, which dropped a foot or more of rain across much of the state. 

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The bloom popped up about six weeks after Irma and then lingered along the coast until May, when the wettest May on record hit. 

Heavy rains then washed nutrients off the landscape and into the Everglades drainage system, which stretches from just south of Orlando to the Florida Keys. 

The bloom has gotten more intense since then with counts of 1 million cells per liter and higher being recorded along most of the Southwest Florida coast in recent weeks. 

Fish, marine mammal and sea turtle kills can start when levels reach 10,000 cells per liter, according to the FWC. 

Levels in the Sanibel area have been measured at 100 million cells per liter and higher, according to the Sanibel-Captiva Conservation Foundation.

Hundreds of stranded and dead sea turtles have washed up on Southwest Florida beaches in the past two months. 

But these conditions were expected by some scientists and experts. 

"People who follow this stuff knew we were going to have a red tide this year," said Jim Beever, a planner and climate expert at the Southwest Florida Regional Planning Council. 

Beever noted that Irma dumped heavy rains across this region and on Lake Okeechobee and the Kissimmee River, which flows into the lake. So rain that fell hundreds of miles away ended up in Lake Okeechobee before flowing through the Caloosahatchee River. 

The water picked up nutrients in the Kissimmee, in Lake O and in the channelized portion of the Caloosahatchee River, which is surrounded mostly by agriculture fields, and delivered it to the Gulf of Mexico. 

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Changes to the landscape and the implementation of water management has contributed to the impacts of algal blooms like red tide, Beever said. 

"This is an unnatural situation," Beever said. "They don’t go on this long. They don’t occur every year naturally. People say look at the historic record and the Spanish recorded it and pirates recorded it, but if you look at the periods (of red tide) it’s nothing like we’re having now."

The blue-green algae bloom that's been in the lake and the Caloosahatchee and St. Lucie rivers since June is also fueling the red tide, Beever said. 

"It goes down the river, hits the saltwater, saltwater kills it, and then there’s all these nutrients available in the Gulf, and what’s there to take advantage of that is red tide," Beever said. "Functionally, (the Caloosahatchee) is almost like a nutrient delivery conveyor belt."

Larry Brand, a marine biology professor and researcher at the University of Miami, agreed with Beever on the nutrients and Irma's impact. 

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Brand has studied red tide events dating to the 1800s and says the blooms are stronger today because of human activities. 

"Today (red tide) is 15 times more abundant, and to get 15 times more algae you need 15 times the nutrients," Brand said. "So this is human runoff primarily from agriculture but also sewage. It’s making it worse than it used to be." 

Brand said Hurricane Irma may have contributed to the problems but that the root causes are in place every year there are heavy Lake Okeechobee releases. 

Even vegetation that was thriving last summer but killed by Hurricane Irma is contributing to the problem, Brand said. 

"Irma destroyed a lot of aquatic vegetation, and you have that decomposing and releasing nutrients," Brand said. "And in May we had record rains, so now you’re flushing all of these nutrients from the land into the water bodies. And when that lake gets too high the Army Corps doesn’t have any choice but to release the water to the coastal areas."

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So are Lake Okeechobee releases related to the strength of this red tide? 

"We get a lot of runoff every year, but we don’t necessarily get a strong red tide every year," Brand said. 

Kerr said the relationship with red tide and weather is complex, that it's impossible to tell if Hurricane Irma had a direct impact on this bloom. 

"There’s no direct link between nutrient pollution with urban or agriculture runoff and the start of a red tide, but at the same time, once the blooms are transferred inshore like they are now, the nutrients can fuel them," Kerr said. 

A few people braved the effects of red tide to relax on the beach on Friday morning. A pile of sand and organic material sits near sunbathers.

Kathy Worley, director of environmental science at the Conservancy of Southwest Florida, said there are some similarities between this year and the red tide that hit in 2005-06 but that there is little solid proof of the correlations between hurricanes and red tide blooms. 

"None of this is proven, but if you remember after Wilma we also had one," Worley said. "It was a yearlong red tide, and that was the last ‘worst’ one." Wilma hit Florida in October 2005. 

The University of South Florida's College of Marine Science predicts that the red tide will drift mostly to the south over the next three days, toward south Lee and Collier counties. 

Beever said he expects the red tide to stay in the region for the next few months. 

"We’re going to have it for a lot longer," Beever said. "I don’t think you’re going to see much of an end to this until we get into the dry season. And it will be a combination of a lack of nutrients delivery (when summer rains stop) to feed it and, with luck, the water cooling."

Worley said it's impossible to say exactly why this particular red tide is so strong. 

"There’s no one thing that you can point your finger at and say that’s the cause," Worley said. "Obviously it has to be fed, but there’s been no direct link between feeding nutrients to red tide and blooms. So we’re missing something. Unfortunately it’s still a mystery."

Connect with this reporter: Chad Gillis on Twitter. 

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