Revolutionary new warning system to rank red tide blooms in Florida waters

March 7 -- Frequent occurrences of red tides -- also referred to as harmful algal blooms, or HABs -- have created a national concern because they affect not only the health of the ecosystems and the people near them but also local economies.

In an effort to better inform the public, researchers are taking water samples that date back 60 years to develop an index that will rank red tide blooms along Florida's Gulf Coast, one of the most impacted parts of the country.

According to the National Oceanic and Atmospheric Administration, HABs occur when colonies of algae, which are just simple plants that live in the sea as well as bodies of freshwater like the Great Lakes, grow out of control while producing toxic or harmful effects on people, shellfish, fish, marine mammals and birds.

The toxins make the surrounding air difficult to breathe, and as the name suggests, the bloom often turns the water red. Though rare, human illnesses caused by HABs can be debilitating or even fatal.

"The red tide is caused by a microorganism algal that's in the Gulf of Mexico, and it produced a toxin that can become an aerosol," NOAA oceanographer Rick Stumpf told AccuWeather National Reporter Bill Wadell in an interview. "In my experience, [when] I'm out on the beach in a red tide and the wind's blowing onshore, I feel like I've come down with a cold."

A fish kill lingers near a dock at Burnt Store Marina, Fla. on December 6, 2019, just a few days after a water sample there indicated red tide algae in the area. File Photo by Paul Brinkmann/UPI

A dedicated group of volunteers that had asthma worked with the Gulf of Mexico Coastal Ocean Observing System for 10 years, and the research from the group's data showed that even after a one-hour walk on the beach during a red tide event, they had shortness of breath, wheezing and chest tightness. This research proved that toxins released from the red tide weren't just upper airway irritants but instead were going into people's lungs and harming them.

"The state of Florida has actually been collecting data on the concentration of red tide for 60 years, and in this effort, what we did was take this data and put it together in a way to assess how severe the blooms are each year," said Stumpf. "We've assessed it based on the amount of [coastline] in southwest Florida that was covered by a bloom each month and the months for the year."

The index runs from zero, which means the red tide is non-existent, to 10, the highest level. Based on the severity of the red tide, a particular year is assigned a number on the index.

The years are defined differently than a calendar year. Since the blooms start during September and October, the year-long period that captures these blooms runs from August to August of the following year.

The worst year, which was rated a 10, was during 2018 when the largest bloom to affect Florida occurred. An unusually persistent HAB on the southwestern coast beginning in October 2017 spread to the panhandle and the east coast of Florida before dissipating in the winter of 2018-2019.

"Classically, [red tide blooms] are very patchy. There are patches of bloom, and then you can go half a mile away and the water's clear," Barbara Kirkpatrick, senior adviser for the Gulf of Mexico Coastal Ocean Observing System, told Wadell in an interview. "The 2018 bloom was very different where it was much more consistent on our coastline."

Dead fish float near docks at Burnt Store Marina, Fla. on December 6, 2019, just a few days after a water sample there indicated red tide algae in the area. File Photo by Paul Brinkmann/UPI

Beachgoers must consider the weather, and more recently their comfort level with the COVID-19 pandemic, when planning to go to the beach.

"This is just another factor," Kirkpatrick said.

There has not been a good metric in order to determine what a major or small bloom is, so this research and index is the first essential step at looking at what causes major blooms one year compared to smaller blooms in other years.

Testing for red tide is done by collecting water samples and counting the organisms under a microscope. Since water samples don't include just red tide organisms but also other specimens too, it takes a lot of skill from the people who are conducting the research. The goal is to get an update out every month, but as of right now, the project releases an update each spring and summer, according to Stumpf.

"There is no red tide out on the Florida coast now, and that would tend to mean that we shouldn't see anything through the spring and into the summer," Stumpf said. "In past years, the summer blooms have typically been carry-overs from the previous year. Last year's bloom has ended. That's a good thing. So right now, we're looking very good for spring and summer."

With the 2022 Atlantic hurricane season approaching, Stumpf shared that hurricanes can sometimes move the red tide around to different locations, but they do not improve or worsen the red tide.

Another update will come out in the summer addressing the current state of the red tide at that time.