Florida's annual King Tide could bring hazardous red tide closer to shore

By Mark Puleo, AccuWeather staff writer

October 06, 2018, 12:22:35 PM EDT

The beaches in Florida continue to stink. As the Gulf Coast of Florida has found itself in the longest red tide outbreak in over a decade, the dead fish and animals have piled up, causing issues for beach goers and residents.

The soon-to-arrive King Tide could make things even worse.

Red tide is a harmful growth and concentration of microscopic algae, a natural occurrence in bodies of water around the world. In the Gulf of Mexico, the red tide is caused by Karenia brevis (K. brevis), a native species to the Gulf. The algal blooms can turn the water reddish brown and often kills fish and other marine animals, such as dolphins and manatees.

King Tide is the nickname for the point in the year when the high tide is at its highest. With the red tide already wreaking havoc, some fear the King Tide could bring the destruction even closer inland.

“King Tide is a very high, high tide that occurs when the sun, moon and Earth are aligned and the moon is at its closest to Earth,” Stephanie Kettle, a spokesperson from the MOTE Marine Labratory and Aquarium, said. "Although the King Tide would affect the Atlantic coast more so than the Gulf Coast, the increase in tidal range will still result in a larger volume of gulf water entering the estuaries, and that could push populations of K. brevis further into the estuaries and bays. This would also increase salinity of estuaries and bays."

Along with the terrible smell, red tide also brings respiratory concerns for residents, particularly those with asthma. Symptoms of the respiratory irritations include an itchy throat and coughing, which has become known as the "red tide tickle."

Florida International University professor Dr. Rebecca Toonkel told AccuWeather that the red tide could also cause skin irritations if people come in contact with the red tide waters, such as from flooding or swimming.

"Skin contact with contaminated waters may also lead to rash or skin sensitivity in some people," she said. "People with chronic lung disease... are at the greatest risk for health concerns related to red tide. Airborne toxins from the algae that cause red tide can lead to shortness of breath, cough and other manifestations of acute exacerbation in these people."

Red tides have occurred naturally for years, Kettle said, without any human influence. But the use of human-contributed nutrients like fertilizers has contributed to the red tide's growth once it reaches shore.

"The scientific data available so far suggests that it is possible for nutrients flowing from land to sea, including natural and human-contributed nutrients carried by storm water runoff and the input of rivers, to serve as additional 'food' for growth of Karenia brevis red tide blooms that have moved to shore," Kettle said. "In short, we know human-contributed nutrients can affect a coastal red tide and we must expand our data and monitoring efforts to confirm whether and how they did in each specific case."

Drew Winchester, a media relations officer with the Sarasota County government, said that the county has been monitoring the cleanliness of the beaches daily.

"Sarasota County continues to monitor and clean our beaches daily, as needed, in accordance with our beach cleaning policy," Winchester said, adding that they have collected 255 tons of debris since Aug. 1. "We also continue to work with our local, state and federal partners to monitor the red tide status of our shoreline, and provide updated information to the community."

When the red tides are brought inshore, by waves and winds, health concerns grow even worse. The concern with the incoming King Tide is that the contaminated water will be brought even closer to towns via floodwaters.

In 2017, the King Tide resulted in minor flooding in coastal Florida towns. Studies have shown that King Tides can pick pollutants from the road and leaky septic tanks, causing health departments to warn residents about avoiding King Tide floodwaters.

This year's King Tide could contain red tide for the first time. Like past years, health officials are again warning residents to avoid wading in floodwaters. But for the first time, this year's concerns could be because of the skin irritations that could flood people's residencies.

"(While) King Tide itself should not make these concerns worse for any single individual, it may just cause more people to come into contact with contaminated water or the airborne toxins as marine waters containing karenia brevis are brought further inland," Dr. Toonkel said. "For this reason, we may see a temporary rise in the incidence... of health concerns related to red tide."