🔗 Share this article A Pair of Crucial Florida Coral Species Declared 'Functionally Extinct' After Severe Ocean Heatwave Researchers have found that two of the most important coral species comprising Florida's reef are now ecologically extinct following a intense ocean heatwave caused catastrophic losses. What 'Functional Extinction' Means The near-total decline of these corals, which once formed the foundation of reefs in Florida and the Caribbean, means they are no longer able to play their previously crucial role in building and sustaining reef ecosystems that support a diversity of marine life. Functional extinction is a stage preceding global extinction, a danger that now looms for many coral species. Researchers this month warned that a critical threshold had been reached, meaning corals globally are set to be eradicated due to global heating, which is increasing ocean temperatures to intolerable levels. Expert Perspective "Time is running out," said Ross Cunning of the new Florida study. "Severe marine heatwaves are increasing in frequency and severity due to climate change, and absent swift, decisive measures to reduce ocean heating and enhance coral survival, we risk the extinction of even more corals from reefs in Florida and around the world." The Recent Study The new research, published in the journal Science, analyzed the fate of staghorn coral and elkhorn corals off the Florida coast after a intense marine heatwave in 2023. This event raised temperatures on Florida's deteriorating coral reefs to their peak temperatures in over 150 years. The two species are complex, reef-building corals and are named because they look like, respectively, the horns of male deer and elks. However, scientists who performed diver surveys of more than 52,000 colonies of the species, across nearly four hundred sites along Florida's coast, found extensive, often devastating, losses. Regional Impact Along the Florida Keys, death rates reached 98% and even 100%, showing a complete annihilation of the corals. In southeastern Florida, where temperatures have been cooler, death rates were reduced, at about thirty-eight percent. Past and Present Threats The two Acropora species had already endured from many years of localized impacts in Florida, such as contaminated water from contaminants that run off the land, as well as illness. But the 2023 heatwave has proved fatal for these heat-sensitive species. The 2023 heat event caused the ninth occurrence of bleaching on the Florida reef – a process whereby corals become thermally stressed and eject the algae partners living in their tissues, causing them to become bleached white. If temperatures remain elevated, the corals perish entirely. Global Consequences Globally, coral reefs are among the ecosystems most at risk to the anthropogenic climate crisis. This poses a significant danger to: A quarter of all ocean life that relies upon what are essentially the marine rainforests. Millions of people who rely on corals to sustain fish that they can consume and earn a livelihood from. Corals also serve as a protective barrier to safeguard our shorelines from intense hurricanes, which are themselves being intensified by increasing global heat. Preservation Attempts In a last-ditch effort to prevent a death spiral of endangered corals, scientists have created repositories of Acropora in aquariums and offshore coral nurseries. Efforts have been undertaken to reseed corals on reefs in Florida, too, in an effort to restore some of the 90% of coral cover lost off the state in the past four decades. But as climate change continues to intensify, there is slim chance of continued existence of these species absent major interventions, researchers warn. Additional Researcher Insight "Elkhorn species, especially, are some of the most important wave-breaking coral species in the area," noted a study co-author, a marine biologist at the University of Miami. "They were once common on shallow reef crests in the Caribbean, and if we want our reefs to keep safeguarding our coastlines from inundation during storms, it is worthwhile taking extraordinary measures to ensure we preserve these corals completely."