Red tide is everywhere.
From Tampa Bay south to Ten Thousand Islands, local groups and state agencies that test for and track red tide are warning that the harmful algae bloom that kills fish and sickens dogs, and whose acrid air chases people off the beach, is here.
And there. And there. And there.
Red tide was detected at every beach in Sarasota County soon after Hurricane Ian made landfall near Fort Myers in late September. Earlier this month, the Florida Fish and Wildlife Conservation Commission found the red tide organism, Karenia brevis, in nearly 100 samples throughout Southwest Florida.
Florida Department of Health officials in Manatee, Sarasota, Charlotte, Lee, and Collier counties are issuing health alerts daily warning of the real and present danger to human and animals.
The red tide is so prevalent, so pungent, and so potentially poisonous that the authors of the health advisories ignored the long-established practice of softening the language to avoid scaring away tourists.
“Stay away from the water,” a Charlotte County health advisory warned. “Do not swim in waters with dead fish. Wash your skin and clothing with soap and fresh water if you have had recent contact with red tide. Those with chronic respiratory problems should be especially cautious and stay away … as red tide can affect your breathing. Keep pets and livestock away and out of the water, sea foam and dead sea life. If your pet swims in waters with red tide, wash it as soon as possible. Do not harvest or eat molluscan shellfish or distressed or dead fish from this location. Residents may want to wear masks.”
There was a lot of not-so-quiet resignation in the seven weeks since Hurricane Ian that red tide would follow. Local charter captains and coastal environmental groups say anecdotal evidence is enough for them: the massive red tide that lasted from 2017 to 2019 followed hurricanes Irma and Maria.
And scientific evidence is mounting as well. A pair of otherwise unrelated research projects found that, while the organism that causes red tide is always present in the Gulf of Mexico, if nature decides it’s time for a bloom the influx of nutrient pollution “feeds” it, which can bolster the bloom into lasting longer and being stronger.
The ground scrubbing done by the massive amount of rain, storm surge, and flood waters from hurricanes like Ian wash a sick mess of pollutants into streams and rivers. Nitrogen and phosphorus from fertilizers; human waste from many of the region’s 100,000-plus antiquated septic systems that were inundated; animal feces; lawn clippings; it all flows from those streams and rivers into the bays that mix with the Gulf of Mexico.
Chemical processes between the saltwater and all the stuff in the runoff break things down into various microscopic nutrients that become available to a fledgling red tide bloom.
“We have no evidence that a hurricane causes red tide,” said Michael Parsons, a professor of marine science at Florida Gulf Coast University and director of FGCU's Vester Marine and Environmental Science Research Field Station. “We don't influence their start, as far as we know. But between hurricanes and runoff from human activities, we could be making them worse.”
‘Human activity has helped’
Imagine a hurricane with the particulars of Ian being as huge washing machine, and the height of the storm being the wash cycle.
More than a foot of rain fell onto the ground and was blown, hard, in ever-changing directions, which rinsed off buildings, cars, traffic lights, business signs, and billboards. Storm surge chugged inland up to two miles in places and was swished about as the storm slowly drifted over and the wind direction constantly changed, scouring roads and sidewalks, filling and draining Dumpsters, washing over farms and yards.
As Ian moved away, the rinse cycle started.
All that water, filled with the pollutants of everyday life, flooded back toward the Gulf of Mexico gathering more detritus along the way: motor oil, rubber from tires, microplastics from discarded face masks, cigarette butts filled with chemicals, and tons and tons of garbage.
In June, researchers from the University of Bristol Veterinary School in the United Kingdom and the Clinic for the Rehabilitation of Wildlife on Sanibel Island published a paper in the journal Harmful Algae that found discharges of water from Lake Okeechobee into the Caloosahatchee River “were significantly correlated” with red tide blooms.
“Sanibel Island, located off the central west coast of Florida, is an epicenter for red tides,” the researchers wrote. “In recent years, K. brevis blooms seem to have become more frequent and intense.”
Red tide blooms produce brevetoxins, potent neurotoxins that cause various species of marine wildlife to get sick or die.
“Clear correlations were found between K. brevis densities and brevetoxicosis patient numbers admitted. This further confirms brevetoxins as the likely cause of their morbidity,” the researchers reported. “Water discharges from the Okeechobee waterway (including Lake Okeechobee and the Caloosahatchee Estuary) into the Gulf of Mexico were significantly correlated with K. brevis densities."
A University of Florida-led study published in the journal Science of the Total Environment earlier this year also proved humans can provide the fuel for red tides that makes the smelly, fish-killing events stronger and last longer.
Environmental researchers led by the University of Florida’s Center for Coastal Solutions documented the link after studying a decade of red tide data from the Caloosahatchee River, Charlotte Harbor, and the surrounding watersheds including the coasts of Charlotte and Lee counties.
“Red tide blooms develop naturally,” said Miles Medina, lead author of the study. “We took a long view and found evidence that human activity has helped fuel coastal blooms in this estuary to varying extents between 2012 and 2021.”
‘Avoiding the beach is advised’
In Sarasota County, the health department’s public health advisory is warning that any storm water remaining from hurricanes Ian and Nicole has another set of dangers.
“Floodwater and standing waters can be dangerous and can make you vulnerable to infectious diseases, chemical hazards, and injuries,” a public notice on their website reads. “Stay out of floodwater.
“We don’t know exactly what is in floodwater at any given point in time. Floodwater can contain: Human and livestock waste, household, medical, and industrial hazardous waste, coal ash waste that can contain carcinogenic compounds such as arsenic, chromium, and mercury, lumber, vehicles, and debris, wild or stray animals such as rodents and snakes.
“Floodwater may contain sharp objects, such as glass or metal fragments, that can cause injury and lead to infection,” the advisory warns. “If you receive a puncture wound or a wound contaminated with feces, soil, or saliva, have a health care professional determine whether a tetanus booster is necessary.”
Tell-tale signs of red tide at a shoreline -- dead fish littering the beach, an acrid smell that permeates the air and often causes watery eyes, scratchy throats, and for some trouble breathing -- are on islands and shorelines in every county in coastal Southwest Florida this week.
Members of the Captiva Erosion Prevention District surveyed the barrier island and found exactly that.
“Upon visual inspection of Captiva’s beaches red tide is present. Fish kills can be found along the mean high-water line island-wide,” the district wrote in its newsletter. “Avoiding the beach is advised at this time. Do not swim. Do not attempt to pick up any remains yourself.”
Water-quality testing by the state departments of environmental protection, of health, and of fish and wildlife also found water fouled with nutrients nearly everywhere along the coast from Ten Thousand Islands north to Sarasota County.
In DEP-speak the testing found “waterbodies that are not meeting the applicable water quality standards and designated uses.”
That means the water along the coast is polluted.
Caloosahatchee concerns
Sanibel-Captiva Conservation Foundation Marine Laboratory scientists partnered with Captains for Clean Water and other environmental researchers to collect and analyze water samples from 26 sites offshore Sanibel and Captiva islands. The team found elevated levels of red tide in every one.
Satellite imagery also “sees” the red tide blooms along the Southwest Florida coast, including offshore of Sanibel and Captiva islands.
The foundation and the captain’s group last week co-authored a letter urging the Army Corps of Engineers to refrain from giving the go-ahead to open the locks too much and release too much water from Lake Okeechobee into the Caloosahatchee estuary. The Army Corps is the agency that decides if, when, and how much flow will be allowed after consultation with the South Florida Water Management District and other governmental water managers and private environmental groups.
“We strongly urge the Corps to maintain (Lake Okeechobee) flows at the lower end of the optimal flow range of 750 cubic feet per second to ensure our coastal waters do not receive excess nutrients that could further feed the ongoing red tide bloom,” the letter dated Nov. 14 reads. “Red tide is not caused by Lake O releases, but these releases and watershed runoff from Hurricane Ian will certainly fuel the intensity and duration of the present bloom.”
In the letter, the SCCF referred to the results of the research project it completed with the University of Florida, the one published in the journal Science of the Total Environment, that also found a direct connection between Southwest Florida’s devastating red tide blooms from 2017 to 2019 and nutrient-polluted discharges from Lake Okeechobee.
The SCCF also mentions the potential health concerns for people and wildlife from the toxins produced by red tide blooms, at which point the groups ask the Army Corps to hold off on the high-volume discharges despite the 16-foot-plus water level in the lake, which is the highest so far this year.
“Fishing guides and beachgoers are reporting dead baitfish, trout, and mullet in Pine Island Sound and the surrounding barrier islands" the statement reads. “Many have canceled charters and are also reporting breathing issues.”
Current data from the National Centers for Coastal Ocean Science and Florida Fish and Wildlife Research Institute also show significant red tide patches from Manatee to Lee counties.
“Our communities in Southwest Florida have been devastated by Hurricane Ian,” said James Evans, CEO of the foundation. “We do not need harmful freshwater discharges from Lake Okeechobee fueling red tide and compounding the impacts that we are already experiencing.”
But that is what they are going to get.
The Army Corps began releasing water from Lake Okeechobee into the Caloosahatchee River this past weekend at 1,200 cubic feet per second. A cubic foot of water is roughly seven gallons of water.
"Lake Okeechobee has risen three feet in the past seven weeks due to Hurricanes Ian and Nicole,” said Col. James Booth, commander of the Army Corps’ district that includes Florida, last Friday before the releases began. “We had paused our releases for Hurricane Nicole and have not made releases since the storm. Based on conditions in the lake, we must begin releases to help manage lake levels.”
Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.
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