Hurricane Ian brought widespread destruction to both Florida and its nearby coastal waters.
The Category 4 hurricane, which made landfall near Cayo Costa, Florida, on September 28, had maximum sustained winds of 150 miles per hour and was responsible for a 15-foot storm surge through northern Fort Myers Beach. At least 120 people died in the storm or in its aftermath, most of them in Florida, and insurers estimate potential losses valued up to $60 billion.
What wasn’t known, however, is just how much the storm damaged the underwater area nearby and its consequential impact on marine life.
After a 6-day expedition coordinating efforts among the Florida Institute of Oceanography, the Water School at Florida Gulf Coast University (FGCU), and the Sanibel-Captiva Conservation Foundation (SCCF), researchers have determined that Hurricane Ian also destroyed man-made reefs and hastened red tides (harmful algae blooms that kill fish and birds).
Scientists know red tides often follow hurricanes because large amounts of polluted water typically spill out into the ocean after the storms. That pollution, in turn, fertilizes the algae and causes the bloom.
During the expedition, researchers from SCCF and FGCU took samples from about 50 sites located between 2 and 12 miles off the southwest Florida Gulf Coast. They discovered numerous discolored areas that have now been confirmed as red tide blooms by the Florida Fish & Wildlife Conservation Commission (FWC), according to the SCCF.
Researchers have also identified the storm’s impact on marine life in the area and its habitat.
Rising Red Tide
Heavy rainfall and flooding after a hurricane cause land-based nutrients to flow outward to coastal waters and algae blooms feed off those nutrients. For instance, the massive red tide bloom of 2018 was most likely made worse by Hurricanes Irma and Maria, according to the Florida Institute of Oceanography.
High counts of Karenia brevis, the dinoflagellate (or marine plankton) that causes red tide blooms, have been found offshore Punta Gorda, Boca Grande, and southwest of Sanibel in Florida. Medium counts have also been documented off North Captiva and Captiva Islands, Florida Institute of Oceanography reports.
“The bloom is more widespread than FWC samples indicated yesterday and continues to extend south,” SCCF Marine Lab Director Eric Milbrandt, Ph.D., said in a statement. “We were able to characterize nearshore ocean conditions before the bloom but after Hurricane Ian, which will help us better understand red tide blooms.”
The red tide outbreak also threatens manatees off Sarasota and Charlotte counties because they rely on seagrass for food, the Ocean Conservancy notes.
“Florida is at a crossroads, with a record number of manatees dying,” said J.P. Brooker, director of Florida conservation for the Ocean Conservancy, according to the Associated Press. “We must keep this issue at the forefront, so leaders statewide will invest in solutions to improve water quality — protecting natural habitats to save our beloved manatees.”
Through mid-October, there have been 719 manatee deaths recorded by Florida wildlife officials, the Associated Press reports. Last year, 982 manatees died in Florida.
Reef Destruction And Impact On Marine Life
Calli Johnson, chair of the Sanibel & Captiva Islands Chamber of Commerce, was also on the expedition as a safety dive officer for FGCU and to document the underwater habitat. She also knows the area well since her family founded Bailey’s General Store on Sanibel more than a century ago.
“While diving in our southwest Florida local waters, [the hurricane’s impact was seen] both above and underwater,” Johnson said. “Artificial reefs that are 30 miles offshore are substantially affected by the hurricane. The one-time vibrant reefs are now underwater disaster sites themselves. Where there used to be a complete ecosystem, there are now only fish that were able to return after swimming away.”
While the scope of destruction is widespread, there is still room for hope, Johnson continued.
“There are inspiring signs of life, for example, many of our favorite recreational fish are abundant, but the greater systems that support those fish were heavily affected,” Johnson said. “Time will tell how this affects our greater economy, because changes in the fishing industry and tourism will come from changes in our underwater world.”