Scientists studying Ian’s impact note artificial reef damage, coral loss
6 – minute read
In the aftermath of Hurricane Ian, Southwest Floridians were warned to stay out of Gulf water tainted with a rare, flesh-eating bacteria (vibrio vulnificus) and polluted with an unprecedented concoction including raw sewage, boat parts, house frames and kitchen appliances. To add to the environmental carnage, red tide reared its ugly head again.
That was frightening enough. But what on earth was going on below the surface?
To find out, researchers from The Water School at Florida Gulf Coast University – in partnership with the Florida Institute of Oceanography (FIO) and the Sanibel-Captiva Conservation Foundation (SCCF) – headed out on the W.T. Hogarth Oct. 18 for a seven-day research voyage. Seven FGCU researchers were on board, including two graduate and two undergraduate students.
While the post-Ian Gulf outlook may seem bleak, Adam Catasus says their data and observations convince him that it’s not as bleak as it appears.
“It will take time for the region to recover, but these natural ecosystems have been significantly impacted by hurricanes for hundreds and thousands of years,” says Catasus, coordinator of education and research at FGCU’s Vester Field Station and chief science officer for the Hogarth trip. “They have recovered every time to date, so we are hopeful they will recover naturally. And, hopefully, our community will do everything in its power to help that recovery along.”
Which isn’t to stay that they didn’t see significant evidence a major hurricane had barreled its way through the Gulf with ferocity seldom seen.
“The benthic ecosystem – natural hardbottom areas, artificial reefs and natural limestone ledges – in the Gulf of Mexico was significantly impacted by Hurricane Ian,” says FGCU alum Catasus (’15, marine science; ’17, environmental science master’s). “Many nearshore, natural, live hardbottom areas were completely smothered and covered by fine grain sediment – up to an arm’s length – that were shifted and moved by the hurricane.
“Some artificial reefs that we visited had collapsed: Edison reef bridge pilings were split in half. Others had been completely moved and rearranged a significant distance: Arc reef towers were moved 200 feet from the original coordinates and were laying parallel to the ocean floor instead of standing vertically. Limestone ledges had significantly less living benthic cover—hard corals, soft corals, sponges, bivalves, etc.—which results in less fish being present in these areas.”
Says Marlin Smith (‘22, marine science), a field assistant from The Water School, “From the photo and video data, it appears most organisms that aren’t hard-bottom-based were wiped away by the hurricane. Most organisms found at the sites were organisms attached to some sort of substrate. Mobile organisms that could migrate fast enough likely migrated away toward deeper water ahead of time. It will be interesting to study the succession that occurs over the remainder of the study.”
FGCU researchers were using scientific techniques they had never used before. They had ocean current velocity and direction tilt meters deployed on the bottom of the Gulf of Mexico before Hurricane Ian and after at a few of their routine artificial reef sites in Southwest Florida. They visited all of those sites on the Hogarth and were able to download the data and process it to determine what the current was before, during and after Ian.
Every day is research day with The Water School!😊 #FGCU researchers were looking for fossils in the Caloosahatchee River with a new friend (swipe to see)!🐊 #WingsUp pic.twitter.com/h9p2IfXb5I
— FGCU (@fgcu) February 4, 2023
The data indicate that at Edison Reef (23 miles west of Bonita Beach, in 40 feet of water) and the 240 ledge (35 miles west of Clam Pass, in 70 feet of water), the benthic current velocity meters were maxed out (greater than or equal to 70 cm/second) at both sites. That indicates significant water movement and the increased likelihood of resuspension of material trapped in the sediments.
Also, nitrogen nutrient data in the surface water possibly indicates a significant portion of the nitrogen nutrients present in Southwest Florida post-Ian are not from the outflows from the storm surge or rainwater from land. Instead, these nutrients could be “resident,” or originating from open-ocean sources such as the remineralization of nutrients from the sediments mixed after the storm.
Says Marlin Smith (‘22, marine science), a field assistant from The Water School, “From the photo and video data, it appears most organisms that aren’t hard-bottom-based were wiped away by the hurricane. Most organisms found at the sites were organisms attached to some sort of substrate. Mobile organisms that could migrate fast enough likely migrated away toward deeper water ahead of time. It will be interesting to study the succession that occurs over the remainder of the study.”
FGCU researchers were using scientific techniques they had never used before. They had ocean current velocity and direction tilt meters deployed on the bottom of the Gulf of Mexico before Hurricane Ian and after at a few of their routine artificial reef sites in Southwest Florida. They visited all of those sites on the Hogarth and were able to download the data and process it to determine what the current was before, during and after Ian.
The data indicate that at Edison Reef (23 miles west of Bonita Beach, in 40 feet of water) and the 240 ledge (35 miles west of Clam Pass, in 70 feet of water), the benthic current velocity meters were maxed out (greater than or equal to 70 cm/second) at both sites. That indicates significant water movement and the increased likelihood of resuspension of material trapped in the sediments.
Also, nitrogen nutrient data in the surface water possibly indicates a significant portion of the nitrogen nutrients present in Southwest Florida post-Ian are not from the outflows from the storm surge or rainwater from land. Instead, these nutrients could be “resident,” or originating from open-ocean sources such as the remineralization of nutrients from the sediments mixed after the storm.
Every day is research day with The Water School!😊 #FGCU researchers were looking for fossils in the Caloosahatchee River with a new friend (swipe to see)!🐊 #WingsUp pic.twitter.com/h9p2IfXb5I
— FGCU (@fgcu) February 4, 2023
What’s next?
“The future plan is to find the funds to go back to the 60 sites we sampled on the Hogarth and determine how the marine ecosystem is recovering from the impacts of Hurricane Ian,” Catasus says. “Are we able to determine the acute and chronic impacts from hurricanes along the Southwest Florida coast? Are there ways to manage the impacts and recovery post hurricane? Are there cause-and-effect connections between significant hurricane events and harmful algal blooms, like Florida red tide?”
For Smith, the future includes using this research in his thesis working with the Environmental Protection Agency project.
“It is a great opportunity to turn a bad situation around and focus on better understanding the impacts large storm events have on the natural environment and how increased anthropogenic activity plays a role in this possible destruction as well,” he said, referring to that caused by human activity. “I will use a lot of the techniques learned to continue to monitor water quality going forward. This trip included a plethora of transferable skills that will really apply to anyone’s future in marine research.”