Divers with the Coral Restoration Foundation swim through bleached staghorn corals at Horseshoe Reef in the Florida Keys on August 3, 2023. One year after the worst bleaching event on record, coral reefs off the coast of Florida are slowly recovering.
Image provided by/Coral Restoration Foundation
hide caption
convert caption
Image provided by/Coral Restoration Foundation
MIAMI — One Year Later worst bleaching event Coral reefs off the coast of Florida are slowly recovering. Despite rising ocean temperatures, scientists say they have not seen significant bleaching this summer.
Corals shed algae when the water gets too warm for too long. Last summer, record ocean temperatures caused by the El Niño climate pattern caused a global coral bleaching event. In the Florida Keys, bleaching was widespread and many corals died, devastating the reefs.
Due to storms and several days of significant cloud cover, water temperatures in Florida have been much lower than last year over the past few weeks. Phanor Montoya-Maya with Coral Restoration Fund said, “We are better than last year but still in a state of alarm.”
Montoya-Maya said there was some coral bleaching in the Florida Keys this summer, but it was at a typical level. “Bleaching happens every summer until September or October,” he said. “But nothing out of the ordinary… under natural summer conditions.”
A partially bleached staghorn coral planted by scientists is seen on Aug. 4, 2023, at Paradise Reef, near Key Biscayne, Fla. Scientists from the University of Miami have established a new restoration research site there to better identify and understand the thermal tolerance of some coral species during bleaching events.
Wilfredo Lee/AP
hide caption
convert caption
Wilfredo Lee/AP
In August, he said, Coral Restoration Foundation staff observed spawning in four coral colonies. Corals, as animals, reproduce both by growing and by sexual reproduction. Once a year, in a mass synchronization event, corals release eggs and sperm at the same time.
Of the four coral colonies in offshore nurseries that spawned in August, only one colony’s gametes were found to be viable, Montoya-Maya said. “The bleaching caused these species and these individuals to invest a lot of energy into survival and not reproduction,” he said. With the return of more normal water temperatures, he hopes the nurseries will resume successful spawning next year.
The Coral Restoration Fund is one of several groups that have formed rescue operations last year to conserve the genetic makeup of endangered coral species. Some have spawned in nurseries and will be replanted on reefs later this year.
Montoya-Maya said populations of elkhorn coral and some other species have grown so large in the nurseries that they need to be pruned or replanted. “We’re confident that as temperatures start to cool and we get out of the bleaching zone, we’ll be able to replant,” he said.
