Local experts say that Tropical Storm Elsa could have helped or hurt the Red Tide blooms that have plagued the Tampa Bay coastline in recent weeks. However, they will not know for certain until the next round of water sampling, which could happen late this week or early next week.
Jim Ivey, environmental science and policy professor at the University of South Florida, said that Elsa could have diluted the blooms and flushed them out of the area.
Or increased groundwater flow and runoff from the storm could have fertilized the blooms, intensifying Red Tide.
“Tampa Bay receives maybe up to 40 percent of its water through groundwater flow,” Ivey said. “That water that percolates down in the ground from people’s lawns can pick up a lot of nutrients that could fertilize the bloom.”
If Red Tide blooms reach land, they would break up quickly, Ivey said, especially with the additional rainfall, so he wouldn’t expect long-lasting or significant health risks to Tampa Bay residents.
Red Tide is a naturally occurring algal organism with a long record of cropping up in Florida. It can produce toxic or harmful effects on people, birds, fish and other sea life.
Richard P. Stumpf, an oceanographer for the National Centers for Coastal Ocean Science, said that Elsa produced “steady, strong south winds” that could have rearranged the Red Tide blooms.
Before Elsa hit, water samples taken by the Florida Fish and Wildlife Conservation Commission on Tuesday showed that Red Tide blooms were being pushed along the St. Petersburg waterfront due to the prevailing easterly winds.
“I don’t expect the bloom along Pinellas to look the same,” said Stumpf. “It might be pushed north. If we are lucky, it will be dispersed.”
Past hurricanes have taken Red Tide blooms from the Tampa Bay area up to the Florida Panhandle, Stumpf said.
“A positive effect is that this storm may have spread the Red Tide out, and faster-growing cells, like diatoms, which split once or twice a day, could out-compete the Red Tide for nutrients,” Ivey said. “At least I hope that is what happens.”