FORT MYERS, Fla. — Red tide blooms are continuing to cause havoc along the Southwest Florida coastline. On Friday, NOAA’s National Center for Coastal Ocean Science issued a new 36-hour alert for moderate risk of respiratory irritation from red tide along Lee County beaches, as well localized areas in Charlotte, Collier, Manatee, and Sarasota Counties with onshore winds.
Karenia Brevis, commonly called red tide, is a microscopic algae that has been around for 1000s of years. The organism typically grows in the Gulf of Mexico during the summer months and moves towards to the Florida coastline during the Fall. NOAA oceanographer Dr. Rick Stumpf says adding a major hurricane into mix likely added to this year's red tide.
“While we might think a hurricane might break it up, it actually renders a bloom,” said Dr. Stumpf. “It tends to make it worse.”
Dr. Stumpf says we are fortunate that this red tide bloom wasn’t already here when Ian hit, unlike hurricane Michael hit in the Panhandle in 2018.
“Michael up in the Panhandle, actually created a huge bloom afterwards,” said Dr. We could go back two decades and there are a couple more examples. So fortunately, it wasn’t already there, so we are currently in a more typical condition.”
Doctor Stumpf says red tide typically forms in the summer and moves toward Southwest Florida coast in the fall months, but Ian and Nicole will likely still factor into this year’s red tide.
“This year, we certainly need to watch more closely because the rain and winds from Hurricane Ian and Tropical Storm Nicole, there may be more nutrients in the water,” said Dr Stumpf.
Those nutrients as food for red tide and allow the algal bloom to expand and worsen. But due to the significant rainfall of two tropical systems, some of those nutrients are trapped still in freshwater runoff draining into the Gulf of Mexico.
“It doesn’t like low salinity water,” said Dr. Stumpf. “So, the low salinity in the estuaries, hopefully will keep it out of some of the estuaries down there, if that low salinity holds up.”
Dr. Stumpf says despite wishing he had crystal ball to know how long the red tide will last, he is tracking a few factors that will likely play in, including cold fronts like we just had move through and hurricane Nicole, which he says acted similar to cold front to the red tide, pushing the northern side of the bloom further out into the Gulf.
“It is just getting pushed out of the area, and that is not all that unusual as you get repeated fronts starting to come through,” said Dr. Stumpf. “You get strong north winds and that will push it south and out into the Gulf of Mexico. That is one way they can leave, if these fronts hold up. But sometimes they get diseases. It is hard to picture these small organisms getting disease, but sometimes that happens. And occasionally they will run out of nutrients as well.”
While red tide is a natural occurrence, doctor Stumpf says you can still play a roll.
“Reducing the amount of nutrients going into waters will help any number of water quality. If there is less available for the red tide, and it happens to occur in the summer that is a good thing. There are also other blooms that are affected by nutrients. So overall, trying to use less fertilizer. Working in the communities with how they are handling wastewater in the like. In the long term, it will help.
In the short term, we will likely been dealing with the red tide for some time, University of South Florida Ocean Circulation Lab’s latest forecast has high concentrations of red tide drifting southward along our coastline through the weekend. And with rain in the forecast early next week, likely additional nutrient full runoff.