Red Tide: A Wave of Destruction Far Worse Than Its Name
Toxic algal blooms are killing Tampa Bay wildlife and affecting residents’ health.
I first heard of the red tide when visiting my parents in St. Petersburg, Florida this summer. It was the beginning of June; the sun was bright, the rains hadn’t gotten bad yet, and the beaches were packed. I was in paradise.
My parents mentioned how a few years ago there was a really bad “red tide” that had all but shut down St. Pete/ Clearwater beaches.
New to the term, they explained to me that red tide was when algal blooms caused marine life to die in large quantities. Fish, sea turtles, and even manatees would wash up in canals and on beaches, creating a gut-wrenching smell.
Looking around at the sunbathing New Yorkers stretched along the beautiful turquoise ocean, I couldn’t imagine this kind of destruction happening here. But only a week later, my dad and I were out fishing off Tierra Verde when I noticed the back of my throat start to burn. I instinctively coughed, and our fishing guide — the now-viral Captain Tyler Kapela — gave an unamused chuckle. “You can feel that red tide starting, huh?”
I looked at him cluelessly. I couldn’t see any masses of dead sea life, and even if I did, why would it irritate my throat?
Seeing that I didn’t understand, Cpt. Tyler explained to me that red tide is a toxin that can cause respiratory issues in humans that mimic allergies and even the flu.
My mind was blown: what was this invisible biochemical circulating in the beautiful blue Tampa Bay waters? As we continued fishing, I started to notice a few dead fish here and there. They were few and far between, but sure enough, there they were floating on top of the water — stomachs full of air, flesh corroded, and eyes missing. I was disturbed.
My parents explained that when they moved here in 2019, they arrived a year after a really bad red tide season. They heard from a few neighbors and locals about how unbearable the stench of rotting fish had been, how they couldn’t walk along the beaches to see the sunset, and how everyone living along the water stayed inside during the day to avoid exposure to the toxin. My parents listened to their stories in awe and fear but never experienced red tide firsthand — until this summer.
July 2021: Red tide arrives on the back of Tropical Storm Elsa
During the first week of July, Tropical Storm Elsa was forecasted to hit both St. Pete and Tampa directly, with winds over 35 mph and torrential rains. Elsa did little physical damage to the Tampa area, but it did stir up the red tide organism that had been lying dormant.
Back in April of 2021, there was a major leak at a long-abandoned fertilizer plant in Manatee County, just south of Tampa. The fertilizer plant, Piney Point, had stored phosphate and phosphogypsum — the radioactive waste left over from phosphate mining — at its site since the 1960s. But the facility went bankrupt in 2001, and its phosphogypsum stacks (called “gyp stacks”) and toxic reservoirs were all but abandoned.
To clean up the spill, officials agreed to discharge hundreds of millions of gallons of contaminated wastewater into nearby Tampa Bay and inject even more into underground aquifers.
Locals voiced concern that the nutrient-laden wastewater could cause algal blooms in the Bay, hurt local aquaculture operations, and affect groundwater supplies.
Algae: The key to understanding red tide
To understand red tide, you first must understand algae. Algae are aquatic plants that live in virtually all bodies of water, from oceans and bays to lakes and ponds. You may know algae by some of its more informal names, like seaweed and pond scum. Algae provides a few major benefits to ecosystems:
- Because algae photosynthesize, it produces oxygen, which is necessary to sustain both marine and terrestrial life. In fact, NOAA estimates that algae provide up to 80% of the Earth’s oxygen.
- Algae is the primary food source for a large percentage of marine life and is an integral part of many Asian diets.
While algae are critical to sustaining life on earth, they can also be detrimental. When algae “blooms,” it can quickly take over the surface of a body of water. (You’ve likely seen ponds covered with slimy green algae.)
An algal bloom can occur naturally, but it is often triggered by excess phosphorus and nitrogen entering the water supply (this is known as nutrient pollution), or from warmer water temperatures, which allow algae to grow thicker and faster. When algal blooms proliferate in an area, they are called harmful algal blooms, or HABs.
The algal blooms can produce toxins to prevent predators from eating them, which can kill fish and other life. When blooms proliferate, they can also cover and suffocate sea life. However, the living algal blooms aren’t necessarily the problem, at least in terms of their effects on humans and animals: once an algal bloom has consumed all of the nutrients in a given area, it dies, leading to huge growths of oxygen-consuming bacteria.
Once an area becomes deprived of oxygen, it turns into a “dead zone,” aptly named because it can no longer support aquatic life. But dead zones don’t just affect marine life; they also reduce the overall amount of oxygen produced on earth, affecting all living creatures.
What is red tide?
As the name suggests, the algal blooms often turn the water copperish-red. According to NOAA, when people eat fish or shellfish that have been in the water with toxic algae, they can become sick from the toxins.
The toxins may also make the surrounding air dangerous to breathe. According to a Pinellas County press release, the red tide may mimic allergy and cold symptoms in humans and may make it more difficult to breathe for those suffering from respiratory illnesses like asthma, COPD, or emphysema — just like Cpt. Tyler had told me. This is thought to be caused by the Florida red tide organism, Karenia brevis, which is transported by offshore winds.
Karenia brevis is a neurotoxin that can be absorbed by fish and shellfish. When humans consume seafood containing the neurotoxin, they can experience symptoms including paresthesias, reversal of hot and cold temperature sensation, ataxia, nausea, vomiting, disorientation, and diarrhea.
According to the Mote Marine Laboratory and Aquarium in Sarasota, FL, Karenia brevis can be transported up to a mile from the ocean. The organization also says that Karenia brevis can only thrive in high-salinity waters, which is why Florida’s red tide can be found in oceans, bays, and estuaries but not in freshwater sources like lakes and rivers.
Is red tide natural?
According to a 2019 PNAS article, red tide blooms have been noted on the Florida coasts since the 1500s when Native Americans warned Spanish explorers about their dangers. While storms and changes in ocean currents are known to influence the occurrence and severity of red tide events, a recent NPR article noted that its effects and timing can be exacerbated by anthropogenic factors.
The last bad red tide in the Tampa Bay area occurred in the summer of 2018. In a news release, former Governor Rick Scott referred to red tide as “naturally occurring” 7 times, abstaining from any mention that the toxic algal blooms could be influenced by human activity. While 2018’s red tide was bad (the governor declared a state of emergency for 7 Tampa Bay counties), locals say this year’s is worse.
According to the Mote Marine Lab, excess coastal nutrients can influence blooms. The PNAS article seconds this, explaining that although a bloom can develop naturally, it can grow faster and last longer when it reaches coastal waters due to fertilizer runoff from agricultural operations and golf courses.
According to a 2018 Sun Sentinel article, discharge of fertilizer-laden water from Lake Okeechobee into the Gulf of Mexico may be a large contributor to red tide growth.
Sewage spills fuel red tide
Tampa Bay also has a history of sewage spills. Most recently, on July 18 and 19, the City of St. Petersburg tweeted that a mechanical failure led to approximately 1,300 gallons of wastewater being discharged into Smacks Bayou off Snell Isle, an area that has been experiencing exceptionally bad red tide this summer. WFLA News 8 reported there have already been 3 sewage spills this summer:
- Tampa released 2,700 gallons of wastewater into a ditch due to a grease blockage
- 75,000 gallons of wastewater spilled into a drainage ditch in Lakeland after the sanitary sewer system was overwhelmed
- Pinellas County released more than 4,000 gallons of “industrial reuse water” around Weedon Island due to a fire water leak
Rising sea temperatures fuel red tide
According to Karl Havens from the University of Florida, rising sea temperatures fueled by climate change may also be exacerbating red tide. Algal blooms thrive in warmer temperatures, which is one of the reasons red tide occurs in the summer months.
The International Panel on Climate Change predicts that surface ocean temperatures in Florida will increase by 1 to 3°C by the end of this century, and surface ocean temperatures have already increased globally by an average of 1°C since 1900.
What are the effects of red tide?
Red tide harms marine life, local fishing economies, and tourism. When red tide is present, the Florida Department of Agriculture and Consumer Services puts out a consumer warning not to eat locally sourced seafood to avoid neurotoxic shellfish poisoning. The department also restricts fishing in certain areas of the Bay during red tide season. This hurts local fishers and restaurants.
Waterfront homeowners become especially upset by the sight and smell of dead sea life washing into their canals and up against their seawalls. Imagine if you bought a multi-million dollar home on the water and couldn’t go outside.
Since wealthier people tend to live on the water, red tide is one of the few environmental issues that doesn’t disproportionately affect poor and non-white communities. This is especially true in St. Petersburg where the worst residential impacts of red tide this year have been between Snell Isle and Coquina Key and can be observed along the heavily-trafficked downtown waterfront area.
Another concern over this year’s red tide is the potential radioactivity of the Piney Point phosphorus plant leak. Although the Florida Department of Environmental Protection said the wastewater discharged from Piney Point in April wasn’t radioactive, the gyp stacks present at the plant contained radioactive materials, including uranium, thorium, and radium. If this radioactive material finds its way into the Tampa Bay ecosystem, can it be absorbed by sea life and bioaccumulate within the ocean food chain?
Is the Piney Point leak responsible for Tampa’s red tide?
According to Tom Frazer, Florida’s former chief science officer and dean of the College of Marine Science at the University of South Florida, the wastewater discharged from Piney Point is not the cause of this year’s red tide, but it may be making it worse. Frazer added that red tide could also be fueled by runoff from residents’ septic tanks and the region’s 18 stormwater systems.
During the Piney Point leak in April, Jesse Mendoza of the Sarasota Herald-Tribune asserted that the biggest concern over the wastewater released into Tampa Bay was its heavy nutrient content, which, he speculated, could feed a red tide.
30-year Tampa Bay area fishing veteran, Cpt. Zach Zacharias, points out in a Herald-Tribune article that this is the first time he’s seen red tide originate and proliferate within Tampa Bay east of the Skyway Bridge. He points out that this also happens to be where Piney Point’s toxic effluent was discharged.
A WFLA News 8 article points out that while 2018’s red tide was brought on by heavy rains, there has not been substantial rainfall this summer, even with Tropical Storm Elsa. This has led some residents to hypothesize that fish kills from the Piney Point fertilizer spill were already occurring en masse, and Tropical Storm Elsa spread them throughout Tampa Bay.
What’s being done?
From what I can see, the response to red tide can be divided into 3 categories: cleanup, communication, and education.
Cleanup
- According to the recent NPR article, 600 tons of dead sea life have been collected by cleanup crews from beaches, canals, and along the downtown waterfront in Pinellas County since late June. The article suggests that if dead sea life isn’t removed quickly, the algae will continue to feed on their nutrients and proliferate.
- Scientists from the Florida Fish and Wildlife Conservation Commission are trying a new strategy to fight red tide called “clay flocculation” in Sarasota Bay. According to a 10 Tampa Bay article, scientists mix seawater with clay and spray it onto the surface of the water where it combines with red tide cells. Scientists say this process is able to kill and bury the cells in the seafloor.
Though clay flocculation is common in treating drinking water and sewage, its effects on red tide and local ecosystems haven’t been studied extensively outside of laboratories and may cause some of its own problems.
In a 2004 study of clay flocculation using phosphatic clay (the most effective at removing red tide cells), scientists observed a noticeable reduction in oxygen content in areas where the clay mixture was used. Ultimately, scientists concluded that phosphatic clay poses a risk to local waters because of its potential radioactivity, oxygen-reducing effects, and high concentration of metals.
But, scientists with the Woods Hole Oceanographic Institute are trying a new type of clay called “kaolinite clay” to treat red tide in Sarasota Bay this summer. The word is still out on kaolinite clay’s safety and efficacy outside of the lab.
Communication
- NOAA says they have been closely observing red tide for years in order to “give communities advance warnings so they can adequately plan for and deal with the adverse environmental and health effects.”
- The Florida Department of Health advises people with severe or chronic respiratory conditions, such as emphysema or asthma, to avoid red tide areas.
The Florida Fish and Wildlife Conservation Commission provides regular updates regarding red tide status in Pinellas County on their website.
Education
- According to the Mote Marine Laboratory and Aquarium, we can all do our part to mitigate red tide by choosing yard plants that require less fertilizer, using slow-release fertilizer, and minimizing fertilizer use overall. The scientists also say that being more diligent about picking up our pet waste can help prevent toxic algal blooms.
My takeaway: Corporations and government are killing Tampa Bay
As Cpt. Tyler says in his viral Instagram video, “If we don’t do something, Clearwater all the way down to Anna Maria Island is going to become a dead zone. No one will want to live here. No one will want to visit this area. There will be no tourism or local fishing economy.”
He’s right. No one wants to take any blame for red tide, so the main messaging from government officials — irresponsibly supported by local scientists — is that red tide is a naturally-occurring phenomenon, and more research is required to combat it.
But what government officials, corporations, scientists, and even many Pinellas County residents aren’t talking about is preventing activities that worsen red tide. Take the Mote Lab for example; Mote is a major marine science research lab with a lot of credibility. They could use their position as an authority on red tide and the Tampa Bay ecosystem to put out better messaging than using less fertilizer residentially and picking up dog poop can prevent red tide.
We’ve seen companies and government tell consumers for decades that if we try just a little harder to recycle, not litter, and buy reusable water bottles that we can prevent the worst environmental impacts from occurring; but this is a myth.
Red tide is not going away if you pick up your dog poop and buy slow-release fertilizer because millions of gallons of toxic wastewater are being dumped into the Bay by the very same people selling us these lies. Even NOAA, the preeminent authority on national environmental issues, doesn’t address the causes of red tide or how to prevent it on their website. They’ll help you plan your next beach trip with their handy Harmful Algal Bloom Forecast maps, but they won’t caution people against exacerbating algal blooms by dumping sewage and toxic & agricultural wastes into waterways.
If you’re concerned about the effects of red tide, perhaps you needn’t worry. According to a recent Pinellas County press release, “Usually symptoms go away when a person leaves the area or goes indoors.” This all too familiar logic has served us well so far: as long as we separate ourselves from the problem, it will go away.
Thank you for reading.
Additional red tide resources
Track red tide in southwest Florida
Tampa Bay organizations addressing red tide
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