Florida Gov. Rick Scott on Wednesday declared a state of emergency for seven counties in Southwest Florida over an unusually severe red tide outbreak.
The declaration will provide money and resources to address a problem that's lingered since October in Charlotte, Collier, Hillsborough, Lee, Manatee, Pinellas and Sarasota counties.
Red tide is a burst of algae growth in the ocean that can kill marine wildlife and negatively affect humans. Beaches are shut down, local businesses have temporarily closed, and Floridians are wondering when it will all end.
Here’s a look at what red tide is and how it’s affecting Florida.
What is red tide?
Red tide, which scientists call a harmful algae bloom, is caused by a naturally occurring alga (a plant-like microogranism) called Karenia brevis or K. brevis. When K. brevis appears in large quantities – typically in the Gulf of Mexico – it can turn ocean water red, brown or green.
K. brevis contains harmful toxins that can impact the nervous systems of fish, birds and mammals.
Why is red tide happening now?
The red tide has lingered along Florida’s southwest coast throughout the spring and summer, and bloom conditions began in November. Currently, it’s at high levels in Lee County, and is also affecting Sarasota County, Charlotte County and Collier County.
Red tide is caused by a combination of conditions, including wind, currents, and the presence of nutrients that allow the algae to grow. While red tide appears almost every year, the severity varies by year.
“For various reasons, the conditions all come together that make it move from offshore to inshore,” said Quay Dortch, a program manager for the National Oceanic and Atmospheric Administration who studies harmful algal blooms. “Some years, it’s sort of a minor problem and some years – like this year – it’s a major problem.”
How does red tide affect wildlife?
Red tide can have debilitating effects on marine life. If the microorganisms are concentrated at more than a 10,000-cell-per-liter rate, fish of all kinds can start dying.
At least 400 stranded and dead sea turtles have been found since bloom conditions began in November, as well as a manatee and a 26-foot whale shark.
What about humans?
Most people can safely swim in red tide, but it can cause skin irritation and burning eyes. Inhaling the red tide toxins can lead to coughing, sneezing, and teary eyes, though those symptoms are typically temporary.
People with chronic respiratory issues like asthma are advised to avoid red tide.
While the medical effects on humans generally aren’t serious, the red tide is affecting the local economy in Florida: Some small businesses have temporarily closed. One restaurant developed a “Fish Kill” cocktail – a blue-green drink featuring floating Swedish Fish – with proceeds going to a clean water activist group.
How long is the red tide expected to last?
It’s hard to predict how long the red tide will remain, and some have estimated that it could persist through 2019. Red tides can last days, weeks, or months, and can change depending on wind conditions and water currents.
“We’re beginning the season when the blooms occur so it’s likely that it’s gonna stick around for a while,” Dortch said.
Is red tide tied to climate change?
Red tides are not a new phenomena – the first reported incident was in Florida in 1844. Research hasn’t yet found a definitive link between the severity of red tides and climate change.
“Whether climate change will make these more frequent is something that we just don’t know right now,” Dortch said.
