Why scientists are using corals from other countries to help save Florida's reefs

"In a lab at the University of Miami, there are tanks of knobby, tan-colored corals from Florida, Honduras and the Cayman Islands. They've been drafted into a sort of coral Olympics, as scientists look for the ones that can best survive increasingly hotter ocean temperatures driven by climate change. Over the past two years, 80% of the world's reefs saw dangerous levels of heat, which causes coral to bleach, turning a ghostly white color."

"Florida's reefs are on the front line of the crisis. Corals there bleached again this summer, and already more than 90% of the living coral off the Florida Keys has died. So for decades, the focus has been on restoring reefs by growing and planting coral in the ocean, much like replanting a forest. It's one of the largest coral restoration efforts in the world."

"But after much of the restored coral near Florida died in the recent marine heat wave, restoration groups have had to overhaul their strategy. Scientists are now trying to breed corals that can tolerate heat better, speeding up the natural process of evolution. Florida coral has been crossbred with coral from Honduras, creating what researchers call "Flonduran" corals. For the first time in the U.S., those coral babies have been put into the wild in a controlled trial."

Tanks at a University of Miami lab hold knobby, tan corals from Florida, Honduras and the Cayman Islands used to identify individuals that tolerate higher temperatures. Scientists expose corals to warming to select heat-resistant genotypes. Over the past two years, dangerous heat affected 80% of reefs and caused widespread bleaching; Florida reefs are especially hard hit, with more than 90% of living coral off the Florida Keys already dead. Decades of restoration focused on growing and planting corals, but recent marine heat waves killed much restored stock. Researchers now crossbreed corals, producing "Flonduran" hybrids and conducting the first controlled wild trial in the U.S., aiming to scale heat-tolerant restoration globally while acknowledging limits set by rising temperatures.

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