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Florida visitors discovering unpleasant surprise at beaches — red tide. What is it?

The toxic algae blooms are killing marine life and turning waters red from Tampa to Naples.
/ Source: TODAY

Spring breakers are flocking to Florida in hopes of enjoying clear water and white sand beaches, but many are instead discovering red tide during their vacations.

The micro-organism that causes red tide has impacted areas from Tampa to Naples this year, turning waters red and killing marine life.

Red tide has visited Florida repeatedly in recent years, and since it returned in 2023, dead fish have washed up on Florida's beaches and officials are warning of possible respiratory impacts from contaminated water and air.

What is red tide?

Red tide occurs when naturally-occurring micro-organisms in oceans and other bodies of water multiply, causing harmful algae blooms in the water.

Many different types of algae species can cause these blooms, but in Florida the organism is called Karenia brevis, according to the Florida Fish and Wildlife Conservation Commission.

When Karenia brevis algae multiply in large numbers due to excess nutrients, it causes a reddish-brown stain in the water.

"That causes this organism, that is typically in very low abundance, to basically dominate and to the point where it produces toxins, it releases those toxins into the water that leads to fish kills and obviously that has human health effects as well," Dr. Steve Davis, chief science officer at the Everglades Foundation, said on TODAY.

Samples of Karenia brevis have been detected in Pinellas County, Manatee County, Sarasota County, Charlotte County, Lee County, Collier County and Monroe County in the past week, according to the Florida Fish and Wildlife Conservation Commission.

What happens during red tide?

In addition to the red hue in the water, the algae bloom can kill fish and lead to respiratory effects in humans.

In Manatee County, officials said they have already cleaned up 7,000 pounds of dead fish in the past few days.

Vacationers have posted photos on social media of dead fish washing up on the shores, while drone footage has captured the blooms throughout southwest Florida.

Noah Boyle, who was on spring break in Clearwater, Florida, told TODAY he saw dead fish "all over the place."

"I didn’t see any in the water, but they washed up right around here on the shore and they’re everywhere," Boyle said.

Other spring breakers said they started feeling unwell after being exposed to the blooms.

"I’ve gotten a little bit of a cough and a little bit ill while I’m here," Tristanal Bisceglia told TODAY.

The Florida Fish And Wildlife Conservation Commission warns people not to swim in or around red tide waters because the toxin can cause skin irritation, rashes and burning and sore eyes.

The commission also urges people with asthma or lung disease to avoid beaches affected by the toxic algae, as winds can blow the toxin on shore.

How can we reduce red tide?

While the algae has been detected in Florida for the past several years, scientists said the effects of Hurricane Ian in 2022 might also be playing a role in this year’s blooms, due to the storm surge that pulled chemicals and fertilizers back into Florida’s waterways.

Davis said the best way to reduce red tide is to restore Florida's wetlands, which can help filter polluted water.

"That is the one sort of dial in this situation that we have control over," Davis said.

State and federal officials have made record investments in restoring the Everglades to help with the issue, including an allotted $2 billion from the federal government over the past two years, according to the Department of the Interior.