FL - Scientists Reveal The Underwater Damage Hurricane Ian Caused Off Florida’s Coast

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.”

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