Armed with scrub brushes, young scuba divers took to the waters of Florida’s Alligator Reef in late July to try to help corals struggling to survive 2023’s extraordinary marine heat wave. They carefully scraped away harmful algae and predators impinging on staghorn fragments, under the supervision and training of interns from Islamorada Conservation and Restoration Education, or I.CARE.
Normally, I.CARE’s volunteer divers would be transplanting corals to waters off the Florida Keys this time of year, as part of a national effort to restore the Florida Reef. But this year, everything is going in reverse.
As water temperatures spiked in the Florida Keys, scientists from universities, coral reef restoration groups and government agencies launched a heroic effort to save the corals. Divers have been in the water every day, collecting thousands of corals from ocean nurseries along the Florida Keys reef tract and moving them to cooler water and into giant tanks on land.
Marine scientist Ken Nedimyer and his team at Reef Renewal USA moved an entire coral tree nursery from shallow waters off Tavernier to an area 60 feet deep and 2 degrees Fahrenheit (1.1 Celsius) cooler. Even there, temperatures were running about 85 to 86 F (30 C).
Marine scientist Ken Nedimyer collects still-healthy elkhorn coral fragments for moving. The tree structure keeps the corals free of harmful algae.
Reef Renewal USA
Their efforts are part of an emergency response on a scale never before seen in Florida.
The Florida Reef – a nearly 350-mile arc along the Florida Keys that is crucial to fish habitat, coastal storm protection and the local economy – began experiencing record-hot ocean temperatures in June 2023, weeks earlier than expected. The continuing heat has triggered widespread coral bleaching off Florida in particular, but also beyond.
By mid-August, coral bleaching had been reported in the Bahamas, Cuba, Mexico, Belize, El Salvador, Costa Rica, Panama and Colombia, as well as Puerto Rico and the U.S. Virgin Islands. This is particularly devastating because some of the healthiest remaining coral reefs are in the southern Caribbean. Scientists worry they may be seeing the sixth mass bleaching of Caribbean corals since 1995 and the third within the past 12 years, and the heat is likely to continue.
A bleached mound of coral at the Cheeca Rocks monitoring site in the Florida Keys National Marine Sanctuary that had been previously tagged shows the coral skeleton.
NOAA AOML
While corals can recover from mass bleaching events, long periods of high heat can leave them weak and vulnerable to disease that can ultimately kill them.
That’s what scientists and volunteers have been scrambling to avoid.
The heartbeat of the reef
The Florida Reef has struggled for years under the pressure of overfishing, disease, storms and global warming that have decimated its live corals….
