Photo: Karl Callwood // Unsplash
According to a study published in the journal Science, climate change has rendered elkhorn and staghorn coral “functionally extinct” in Florida. The findings were based on diver surveys at over 52,000 colonies of staghorn and elkhorn coral across 391 sites.
Coral bleaching is when corals become stressed by changes in conditions such as temperature, light, or nutrients, and expel the symbiotic algae living inside them. The process, which turns the coral white, does not necessarily kill the coral, but renders them extremely vulnerable. As little as a 2°C increase in temperature is enough for many corals to bleach. In 2023, a record-setting marine heat wave triggered the ninth mass coral bleaching event on Florida’s Coral Reef. This, in turn, led to the extinction of wild and replanted corals in the Florida Keys.
“Scientists have been warning of this for quite literally decades,” Andrew Baker, a professor of marine biology at the University of Miami and one of the authors of the study, told The New York Times. “The surprise is that it happened so fast. And it wasn’t more deaths by a thousand cuts. It was a sudden, final kind of guillotine.”
Elkhorn and staghorn coral, native to southern Florida, Mexico and the Caribbean, were already struggling before the heat wave. Their incidence had declined by 90 percent or more before 2023. The heat wave then landed the killing blow, decimating 98 to 100 percent of what remained in the Florida Keys and Dry Tortugas, and 38 percent off the coast of southeast Florida.
“The loss of the staghorn and elkhorn is so significant because those species have been the dominant reef builders on Florida’s reefs for the last 10,000 years,” said Ross Cunning, a coral biologist at the Shedd Aquarium in Chicago and one of the study’s lead authors. “They have the fastest growth rates of Caribbean corals and therefore they grow and build three-dimensional structure more rapidly.”
