Residents of Florida’s Gulf Coast are facing yet another threat following back-to-back hurricanes: deadly ‘red tides.’
Water samples and satellite images have shown medium to high levels of Karenia brevis – the type of algae that causes red tides – offshore of Tampa Bay.
Red tides occur when Karenia brevis grows out of control, turning waters reddish-brown and producing a potent neurotoxin that can be suspended in the air near beaches.
This toxin can kill fish and sicken humans and pets with respiratory symptoms including shortness of breath, coughing and sneezing.
In extreme cases, breathing red tide toxins can cause serious respiratory conditions such as pneumonia, bronchitis and worsening of asthma.
Red tides can turn deadly when respiratory symptoms become severe, or when a person consumes shellfish that has been contaminated by these toxins.
This causes paralytic shellfish poisoning (PSP), which is fatal in roughly 8.5 percent of cases.
Red tides occur when Karenia brevis grows out of control, turning waters reddish-brown and producing a potent neurotoxin
‘Karenia brevis (red tide) is present along the coast at concentrations that may cause respiratory irritation with onshore winds in Pinellas and Sarasota counties,’ the The National Centers for Coastal Ocean Science (NCCOS) currently states.
‘A moderate to high risk of respiratory irritation is most likely when winds are blowing onshore or alongshore, and less likely when winds are blowing offshore.’
Red tide toxins cause symptoms similar to an ‘instant cold,’ Richard Stumpf, an oceanographer with the National Oceanic and Atmospheric Administration (NOAA), told the Associated Press.
Symptoms typically resolve within minutes of leaving the contaminated area, he added.
But for those with asthma or other underlying respiratory issues, symptoms may become serious or even require medical attention.
And some pets that have come into contact with red tide toxins have become seriously ill or died.
Red tides can also cause massive die-offs of fish and other marine animals, covering beaches with rotting carcasses.
In March 2023 for example, red tide caused countless dead fish to wash up on beaches along the Gulf Coast, especially in Sarasota and Pinellas counties.
NOAA satellite imagery shows the location of an algae bloom that contains Karenia brevis, also known as a red tide
The impact drove organizers of the annual BeachFest in Indian Rocks Beach to cancel the festival even though it was still more than a month away.
In Florida, red tide is most common in late summer and early fall, but researchers said that this year’s threat was stirred up by Hurricanes Helene and Milton.
Hurricanes do not cause red tides, but they can make existing harmful algae blooms worse.
The Florida Fish and Wildlife Commission reported medium and high levels of Karenia brevis concentrations in some coastal locations near Pinellas County between September 26 and October 3 – right when Hurricane Helene made landfall.
Hurricane Milton hit Florida soon after on October 9.
A hurricane can move harmful algae blooms closer to shore, sometimes pushing them hundreds of miles up the coast
Tropical storms churn up nutrient-rich water that feeds algae.
They also produce a lot of rain, which can increase the amount of runoff from land and thus the amount of nutrients entering the water,
If a harmful bloom is already present when a hurricane hits, the storm can fuel its growth and help a red tide form.
A hurricane can also move harmful algae blooms closer to shore, sometimes pushing them hundreds of miles up the coast, Stumpf said.
This increases their threat to human health, making beachgoers and coastal community members more likely to come into contact with red tide toxins
This red tide threat comes as Floridians are still recovering from the impact of back-to-back hurricanes.
Red tides can also cause massive die-offs of fish and other marine animals, covering beaches with rotting carcasses
Category 4 Hurricane Helene shattered records along Florida’s west coast, delivering over 15 feet of flooding to the Big Bend region and up to 10 feet of flooding in other areas.
The hurricane battered the state with 140 mph winds, which caused lasting damage to homes, buildings and other infrastructure.
An estimated 20 Florida residents were killed by the storm, which ultimately moved up the East Coast and claimed a total of 215 lives across multiple states.
Still reeling from Helene, Florida braced for Hurricane Milton, which made landfall as a Category 3 storm just two weeks later.
Milton knocked out power for more than 3 million Floridians, delivering up to 18 inches of rain, 10 feet of storm surge and over 100 mph wind gusts.
This hurricane also triggered a scourge of deadly tornadoes, which ripped across the state and caused significant destruction.
At least 24 people were killed by the storm, which only impacted Florida.
