Extreme weather rocked the United States in 2023. Summer brought a massive heat wave throughout the world, triggering storms, breaking records and generally making life miserable. Under the waves, the ocean was also heating up, causing a widespread coral bleaching event.
When temperature spikes strike, coral normally can’t just migrate to cooler waters — at least not without a lot of help. The Keys Marine Laboratory and several other organizations, like the Coral Restoration Foundation, jumped in to save the fragile coral nurseries off the Florida Keys. They hosted around 5,000 coral specimens in special containers on land during the ocean heat wave.
While housing the coral, the teams still had to combat the heat. They did so by placing the coral under large shades and pumping temperature-controlled seawater through the bright blue tubs.
The waters around Florida, and much of the world, stayed at coral bleaching alert level two for several months, which sparked upheaval in the fragile coral ecosystem and caused coral to expel their symbiotic algae and turn white from starvation. Level two is the highest point on the National Oceanic and Atmospheric Administration (NOAA)’s alert scale, warning that severe mortality and bleaching are likely.
Dr. Cindy Lewis, director of the Keys Marine Laboratory, described the starving coral as looking like “giant snowflakes.” But the sight of bone-white coral is a warning flag for changing climates and struggling ecosystems. In some places, the surface ocean temperature reached critical levels, raising warning flags around the world.
Allison Crimmins directed the USA’s Fifth National Climate Assessment earlier this year. She delivered a statement alongside the report at the White House, taking the time to point out the struggles faced by coral reefs.
“Waters off the coast of Florida hit 101 degrees Fahrenheit, exposing our nation’s precious coral reefs to hot-tub-level temperatures. Climate impacts are costing lives, disrupting livelihoods, and threatening the people, places, and pastimes we care about,” Crimmins said.
Around mid-October to early November 2023, the ocean cooled down enough for the rescued coral to begin the return journey to the ocean, the conclusion of a significant operation with a laundry-list of requirements to be met. This includes a clean bill of health from a coral veterinarian, cool waters around the nurseries, and calm seas for the boats.
“There is just an undertone of amazing excitement with everybody that’s on-site,” Dr. Lewis said. “Everybody is just so excited that every coral returned is a success. Yes, we’ve lost some … but the ones that survived, it’s a huge success.”
