Putting the Pieces Together

Has a Longboat Key Retiree Solved the Puzzle of Red Tide?

The effects of red tide and how we might mitigate it remain as relevant as ever.

By Pam Daniel April 30, 2019 Published in the May 2019 issue of Sarasota Magazine

Editor’s note: This story was published a year ago after a devastating outbreak of red tide in 2018. Thankfully, the Florida Fish and Wildlife Conservation Commission is not reporting any concentrations of red tide along the Florida coast in April 2020. But the effects of red tide and how we might mitigate it remain as relevant as ever, and this story reveals the complexity of the problem and the actions we could take.

Not every Longboat senior spends lazy days playing golf and lounging by the pool. Since he retired to the key in 2002, after a long career at General Electric Aircraft Engines, Lenny Landau has earned a reputation for deep dives into complex issues affecting the region. Dubbed “the data king of Longboat Key” by an island newspaper, the determined 76-year-old mechanical engineer has immersed himself in white papers, scientific abstracts and studies most of us would find dry and daunting, learning about topics from beach erosion to sewer systems. He says he likes to reflect on his research and “put the puzzle together” while riding his bike along Gulf of Mexico Drive or walking his 160-pound English mastiff.

The puzzle that has consumed Landau for the past several years is red tide. A few months ago, he talked about his findings at a seminar at USF Sarasota-Manatee that was presented in partnership with the Global Interdependence Center and Cumberland Advisors. Landau likes to stress that he is not a scientist, but seminar moderator and meteorologist Bob Bunting, a former National Oceanic and Atmospheric Administration scientist, says Landau has done something scientists haven’t done—and aren’t meant to do. “Their mission is discoveries, and not translation and application,” says Bunting. “Landau has unearthed the puzzle pieces, many buried here and there, and put them together in a way that people can understand and begin to act on.”

About two years ago, Landau began studying the possible effects of climate change—particularly sea level rise—on our region. As serious as such issues are, he says, people tend to avoid dealing with them because they think they won’t suffer dire consequences during their lifetimes. But when he came across research linking climate change to red tide, he realized this was an issue that was already impacting us.

“Red tide affects everything,” he emphasizes. “The environment, property values, the economy, even public health.”

During last year’s horrific outbreak, Landau was exasperated by the fatalistic approach many civic leaders and scientists espoused. “They were saying you can’t get rid of it, applied solutions would be impossible [because the ocean is too big and complex] and the best advice is to avoid it,” he recalls. “The final straw was when I read in the local newspaper that the solution was to reimburse businesses for their losses.”

To a lifelong data geek and problem solver, that approach seemed incomprehensible.

“I had to empty my brain of what I was reading [in the newspaper],” he says. “I was determined to go from hopelessness to hope.”

After thousands of hours spent talking to climate and marine scientists and poring over peer-reviewed studies (the gold standard in research, peer-reviewed studies are conducted by a scientist and assessed by others in his or her field), Landau does indeed feel hopeful. 

He’s learned that it takes a complex interplay of factors to transform a few clumps of algae far out in the Gulf into a toxic plague that can extend, as it did last year, from Marco Island to St. Petersburg, turning near-shore waters into a dark graveyard.

“It takes a perfect storm to have a major red tide episode,” he says.

Scientists have studied many of the individual factors—which range from naturally occurring marine bacteria and a wayward Gulf current to African dust—but Landau tried to see whether and how they work together to ignite blooms.

Lenny Landau

Image: Chris Lake

Contrary to popular opinion, he says, a huge amount of data on red tide has been compiled over the past 25 years, but that data is “fragmented and disconnected.” Scientists tend to work in “silos,” he says, conducting individual studies—some of them repetitive—funded by grants from disparate organizations. “People don’t talk to each other, and each one looks at only a piece of the problem,” he says. And because no central authority is directing and reviewing research, some critical data is not being collected and analyzed.

Some of Landau’s conclusions go beyond what most scientists have been willing to say. Scientists require definitive proof; but if he found enough evidence, Landau made some logical leaps about how one factor was affecting and intensifying others. For example, most scientists avoid saying that pollution makes red tide worse, insisting they just don’t know enough to draw that conclusion. But Landau says it’s clear that pollution plays a big role. He also believes that climate change is making outbreaks worse. Most important, he says, his research suggests how we can attack and subdue red tide. And that’s a battle we need to win.

“If someone were at war with the state of Florida and looking for a weapon, red tide would be perfect,” he says. “It could kill this place.”

Statistics bear him out. After last summer’s outbreak, a Visit Florida survey found 46 percent of local businesses reporting their sales had been cut in half. Sarasota hotel occupancy plunged by 11 percent in the last three months of 2018, the steepest dive since after Sept. 11, 2001, as tourists, revolted by pictures on social media and reports in national media about fish kills and empty beaches, canceled their vacation plans. Even after the red tide abated, bookings for 2019 tanked.

Jon Thaxton, senior vice president for community investment for Gulf Coast Community Foundation, has studied red tide extensively and speaks to groups about it. He says he agrees with Landau’s conclusions and appreciates his timing. “Lenny did the research, then assimilated and communicated—and he did it at the right time,” says Thaxton. He notes that Landau’s findings about pollution are “what a lot of us were saying—but nobody was listening.” After last year’s outbreak, Thaxton thinks people may be ready to listen—and act.

Here’s a look at Landau’s findings.

A Bloom is Born

Red tide, or Karenia brevis, is a tiny, single-cell alga that originates only in the Gulf of Mexico. (Currents sometimes carry the algae from the Gulf into Atlantic waters off the east coast of Florida.) It’s the only alga known to emit neurotoxins that, in large clusters, kill sea life and cause respiratory distress in humans. Small patches of Karenia brevis are always floating in the Gulf, but from time to time, the algae multiply exponentially, staining the water copper-brown and causing widespread fish kills. Blooms have been reported throughout history, including by Spanish explorers in the 1500s, but during the last few decades, they seem to be getting larger and lasting longer.

To thrive, red tide needs sunshine and salinity—both present in ample amounts in the Gulf off Southwest Florida. It also needs warm water. It flourishes in temperatures between 59 to 86 degrees Fahrenheit and begins to die off in water below 58 degrees.

Warmer Winters Make Red Tide Year-Round

In the past, red tide usually bloomed during our steamy summers and autumns and died off when the Gulf cooled in winter. Global warming has changed that. Our days are getting warmer—Sarasota’s average high temperatures have risen by 2 degrees Fahrenheit over the last 50 years; and our nights are heating up even faster, with average lows rising by 4 degrees. As a result, some recent Southwest Florida winters didn’t get cold enough to kill red tide. Case in point: last year’s outbreak, which actually began in 2017. A mild winter kept it alive, and when Gulf waters warmed in June, the bloom exploded. Even in January of this year, masses of that 2017 red tide were still floating offshore. Only when the polar vortex made a rare dip south and Gulf temperatures plunged did much of the algae finally die off.

Pollution Fuels Bigger Blooms

Red tide algae are hungry little creatures that eat all sorts of things, from other miniscule marine organisms to manmade pollutants. Nitrogen, in particular, plays a big role in their proliferation.

The Gulf is awash in nitrogen, some of it absorbed from the atmosphere and such natural sources as decaying fish; an ever-increasing amount comes from wastewater leaks, sewage from leaky septic systems, and stormwater runoff. That runoff is laden with nitrogen-based fertilizers.

Red tide algae can’t eat nitrogen particles. But a natural interaction solves that problem. Trichodesmium, a bacteria found in seawater, transforms nitrogen into a substance that the algae can ingest. Scientists call this “bio-available nitrogen.”

Trichodesmium needs iron to make bio-available nitrogen, and luckily for red tide, climate change is delivering more iron to Gulf waters. Anywhere between 60 and 200 million tons of iron-rich dust sweep across the Atlantic from Africa every year, much of it drifting down from the atmosphere into the Gulf of Mexico. (It turns out African dust in Southwest Florida’s skies creates those vivid sunsets we’re famous for.) That dust has increased in the last few decades, with much of the increase coming from Africa’s Lake Chad. The lake was once the size of Lake Erie, but rising temperatures have dried up most of it. Once the dust sifts down into the Gulf, the Trichodesmium bacteria get busy utilizing its iron to convert more nitrogen into what will become food for red tide algae.

In addition to nitrogen, fertilizers supply another catalyst for red tide blooms: urea. Present in animal waste, urea is a major component of nitrogen fertilizers. In an unfortunate series of links in the food chain, urea ends up speeding the growth of red tide. Here’s how it works: A bacteria in the water called Synechoccus feeds on urea, rapidly multiplying when it’s present. That’s good news for Karenia brevis, which likes to eat Synechocci. When large amounts of urea are present in coastal waters, large amounts of Synechoccus develop—and red tide mushrooms.   

The Loop Current Stirs Up Nutrients

Red tide blooms usually start 10 to 40 miles offshore. Wind and currents drive them to the coast, where pollution from runoff is heaviest, creating a hearty stew for the algae.

In addition, a powerful current called the Loop Current drives more nutrients to the coast. Like a rushing underwater river, the Loop Current is almost as strong as the Gulfstream in the Atlantic—strong enough it could knock down a man who tried to stand in it. The current loops around the Gulf, every now and then approaching what’s called the west Florida shelf. Ages ago, Florida was much wider than it is now; as seas rose, the edges of ancient Florida—the shelf—were submerged in shallow water. Like a cliff surrounding the state, the shelf extends out about 150 miles under water that is only 1,000 feet deep. Then the Gulf drops off to 8,000-feet depths.

When the Loop Current runs into the shelf, it generates currents that cause upwellings, which stir up the seafloor and push deposited nutrients—dead fish, iron dust, bio-available nitrogen and more—to the surface. This special-delivery feast for red tide is driven to the coast by winds and tides, where the red tide is further fed by near-shore pollution. It’s well documented that the Loop Current is associated with red tide outbreaks. Last June, the Loop Current intersected with the shelf off west Florida; a few days later, the red tide that had been floating offshore for months ballooned into a massive outbreak.

Fish kills up and down the coast emptied beaches last year.

What's Next: Taking Action

It’s essential we stop the pollution from fertilizers, septic systems and other sources that fuels red tide blooms near the shore, says Landau. “There is no downside to cleaning up the water,” he emphasizes. “It’s all good.”

History shows pollution can be reversed. Landau points to the clean-up of the Chesapeake Bay. Several decades ago, the bay was so filthy that most major marine species were dying off. A 15-year, $19 billion cleanup plan, directed by the Environmental Protection Agency and mandated by an executive order from President Obama in 2010, required six different states and the District of Columbia to limit pollution levels, improve wastewater treatment and reduce runoff—or risk severe fines.  It worked; the bay is now in its best shape in 30 years.

That multi-state effort was much more ambitious than cleaning up the water just in Florida, Landau says. He’s encouraged that new governor Ron DeSantis seems determined to address the state’s pressing water issues; a red tide “czar” who coordinates and directs research and clean-up would also be a step forward.

One indirect factor spurring red tide blooms is already being addressed: African officials have come up with a plan to refill Lake Chad, which would reduce the iron dust coming across the Atlantic Ocean.

We also need to do more to monitor the extent and intensity of red tide outbreaks, says Landau. He believes such information will help us develop technology to reduce outbreaks and even clean up blooms in confined bodies of water, like canals and bays.

At USF’s January seminar on adapting to a changing climate, Landau and other speakers raised the possibility of our region becoming a center of climate change research and adaptation. They noted that Florida’s economy ranks just behind the 16th largest national economies in the world, and we have programs in marine science and climate at close to a dozen universities. We’re also home to the National Hurricane Center and to Mote Marine Laboratory, which recently established a Red Tide Institute.

Bunting, the event moderator, envisions a Climate Adaptation and Mitigation Center, possibly headquartered at USF Sarasota-Manatee. The center would integrate research in a way that would inform further research, decision-making and solutions. It could also spur the development of products and services that respond to the impacts of climate change, including red tide. In addition to solving critical problems, such a center would be a boon to economic growth, Bunting says.

To learn more or to get involved, email [email protected].


Opening photo: Mike Lang/Sarasota Herald-Tribune via Associated Press

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