How red tide made it to Brevard County

Gulf Stream, small branches of circulation carry Karenia Brevis

BREVARD COUNTY, Fla. – Karenia brevis, also known as red tide, is inherent and blooms almost exclusively in the Gulf of Mexico. However, recently it's been confirmed on Florida's east coast, as far north as Brevard County.

So how did it get here? The short answer is that red tide is transported here on a warm water conveyor belt called the Gulf Stream.

The Gulf Stream loops around the Gulf of Mexico, rides along the Florida Straits and slides up the Eastern Seaboard of the U.S. Its main role is to transport warm water up north, helping maintain the temperature balance of the oceans.

Seasonally, these algae blooms on Florida's west coast usually remain in the Gulf. It’s during the rare event where red tide is high that it has the ability to travel hundreds of miles, due in part to the constantly flowing Gulf Stream.

The Gulf Stream location in the Global Real Time Ocean Forecast System model  and in the Navy Coastal Ocean Model is compared to the Naval Oceanographic Office Gulf Stream analysis. (Image: NOAA)
The Gulf Stream location in the Global Real Time Ocean Forecast System model and in the Navy Coastal Ocean Model is compared to the Naval Oceanographic Office Gulf Stream analysis. (Image: NOAA)

Nick Shay, a professor of ocean sciences at the University of Miami Rosenstiel School of Marine and Atmospheric Science, compares the travel of red tide with the 2010 oil spill in the Gulf of Mexico.

“The strength of the fast-moving currents that circulate from the Gulf into the Florida Straits and then up along Florida’s Atlantic coast are a reason the oil spill in 2010 was such a concern for the entire state, even though only a small portion of beaches in the Panhandle ultimately were affected” Shay said.

Small shifts in the Gulf Stream can play a vital role in where the red tide shows up along the coast. 

“These meanders can occur daily or weekly or seasonally,” Shay said. “If the Florida current meanders toward the coast, that could amplify an already bad situation into a worst-case scenario.” Shay said.

Along with the main current, small branches of circulation, or vortexes, create their own individual paths toward and away from the coast. This could explain why blooms were found in West Palm and then further south in Miami Dade and Broward about a week later.

[MORE COVERAGE: Beachgoers beware: Red tide can affect your health | Red tide now present in Brevard, Indian River counties]

Although red tide along the East Coast is unusual, it’s not impossible, especially during high red tide years. The last time red tide reached east Central Florida was in 2007, when Karenia brevis was confirmed in parts of Volusia County. The last time Brevard County experienced a large area of red tide was back in 2002.

Another possible player in the recent spread of red tide could be Hurricane Michael. As the Category 4 hurricane tracked over the Gulf, it churned up the waters, breaking apart massive blooms along Florida’s west coast. These smaller patches then traveled on the Florida current and now are showing up along the Atlantic coast.

Unfortunately, there is no clear answer to how long these blooms will linger on the East Coast. Some small patches can linger for a few days, while other, more persistent blooms can last weeks. The 2002 bloom along Brevard arrived in November and lasted into early the following year.

The science behind red tide is always evolving, and research is being done. Scientists with the National Oceanic Atmospheric Administration fisheries and the University of Miami are on a mission off  the Florida Keys collecting data and learning more about red tide impacts on the ecosystem and human health. Follow updates and findings at aoml.noaa.gov.

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