As oceans warm, Florida scientists hunt for heat-resistant coral
Off Florida's coast, a team of scientists and trained volunteers in scuba gear descends to the ocean floor, planting young coral onto a reef and examining how others are faring in increasingly warm waters.
It is part of a long-running "Rescue a Reef" program run by the University of Miami that aims to advance conservation efforts and raise public awareness.
Part of that work involves researching which coral species are better able to withstand rapidly warming oceans as a result of human-caused climate change.
"Certain species may be more resilient and able to better survive and recover from thermal stress events," program manager Devon Ledbetter explained to AFP during a recent dive to Rainbow Reef, about 3 miles (5 kilometers) offshore from Key Biscayne.
Coral reefs support vibrant marine ecosystems but also act as breakwaters, protecting coastlines from storm-driven erosion and flooding.
The situation, however, is increasingly dire.
A record-breaking marine heat wave that began in 2023 left two ecologically vital coral species, elkhorn and staghorn, "functionally extinct" in Florida's Coral Reef, highlighting the growing dangers a warming climate poses for the world's oceans.
The National Oceanic and Atmospheric Administration believes that this fourth global coral bleaching event likely concluded in mid-2025. But the arrival of a very strong El Niño could bring a return to more widespread bleaching—including in Florida's waters.
Researchers place color reference charts around newly planted coral to record the pigmentation, a method used to monitor its health and detect early signs of heat stress.
A diver swims above a mass of bleached staghorn coral, its pale and white branches a sign of stress after prolonged exposure to abnormally warm ocean waters, off the coast of Key Biscayne, Florida.
Some coral species with fast-growing branches are planted onto "coral trees" that look like old television antennas and are suspended in the water column, with floats to keep them upright.