🔗 Share this article Two Vital Florida Coral Species Declared 'Functionally Extinct' After Severe Ocean Heatwave Researchers have found that two of the primary coral species forming Florida's reef are now ecologically extinct following a withering ocean heatwave led to devastating losses. What 'Functional Extinction' Means The almost complete decline of these corals, which once served as the backbone of reefs in Florida and the Caribbean, means they are no longer able to fulfill their previously crucial role in building and sustaining reef ecosystems that support a variety of marine life. Ecological extinction is a stage before global extinction, a threat that now hangs for many coral species. Researchers recently warned that a critical threshold had been reached, whereby corals globally are set to be eradicated due to climate change, which is increasing ocean temperatures to intolerable levels. Expert Perspective "Time is running out," stated the lead author of the recent research. "Extreme heatwaves are increasing in frequency and severity due to global warming, and without immediate, ambitious actions to slow ocean warming and boost coral resilience, we face the danger of the extinction of even more corals from reefs in Florida and worldwide." The New Research The recent study, published in the journal Science, examined the outcome of staghorn coral and elkhorn corals off the Florida coast after a intense marine heatwave in 2023. This event elevated temperatures on Florida's deteriorating coral reefs to their peak temperatures in more than a century and a half. The two species are complex, reef-building corals and are named because they look like, respectively, the antlers of male deer and elk. However, scientists who conducted diver surveys of more than 52,000 colonies of the species, across 391 sites along Florida's coast, found widespread, often catastrophic, losses. Geographic Impact Along the Florida Keys, death rates reached 98% and even one hundred percent, showing a complete annihilation of the corals. In south-east Florida, where temperatures have been lower, death rates were reduced, at about thirty-eight percent. Past and Present Dangers The two Acropora species had already suffered from many years of regional pressures in Florida, such as poor water quality from contaminants that run off the land, as well as disease. But the 2023 heatwave has proved fatal for these heat-sensitive species. The 2023 heat event caused the ninth episode of coral bleaching on the Florida reef – a process whereby corals become thermally stressed and eject the symbiotic algae living in their tissues, causing them to become ghostly white. If temperatures stay high, the corals perish completely. Worldwide Consequences Worldwide, coral reefs are among the ecosystems most at risk to the anthropogenic climate emergency. This presents a significant danger to: A quarter of all ocean life that relies upon what are effectively the marine rainforests. Hundreds of millions of people who rely on corals to sustain fish that they can consume and earn a livelihood from. Corals also act as a protective barrier to safeguard our shorelines from powerful storms, which are themselves being intensified by rising global temperatures. Preservation Efforts In a last-ditch effort to avert a death spiral of endangered corals, scientists have established repositories of Acropora in marine facilities and ocean-based nurseries. Attempts have been made to reseed corals on reefs in Florida, too, in an effort to regain some of the 90% of coral cover disappeared off the state in the past four decades. But as global heating continues to intensify, there is slim chance of continued existence of these species without significant actions, researchers warn. Further Researcher Insight "Elkhorn corals, in particular, are some of the key wave-dampening coral species in the area," noted Andrew Baker, a ocean scientist at the University of Miami. "They were once abundant on shallow reef tops in the Caribbean, and if we want our reefs to continue protecting our coastlines from flooding during storms, it is worthwhile taking exceptional steps to ensure we preserve these corals completely."