ð Share this article A Pair of Essential Florida Coral Species Declared 'Functionally Extinct' Following Devastating Ocean Heatwave Scientists have discovered that two of the key coral species comprising Florida's reef have become functionally extinct after a withering ocean heatwave led to devastating losses. What 'Functional Extinction' Signifies The almost complete collapse of these corals, which once served as the backbone of reefs in Florida and the Caribbean, means they can no longer play their once vital role in building and sustaining reef ecosystems that support a diversity of marine life. Functional extinction is a phase preceding total extinction, a threat that now looms for many coral species. Researchers this month alerted that a tipping point had been reached, whereby corals around the world are set to be eradicated due to global heating, which is raising ocean temperatures to unbearable levels. Expert Insight "Time is running out," stated Ross Cunning of the new Florida study. "Extreme heatwaves are becoming more frequent and intense due to climate change, and without swift, decisive measures to reduce ocean heating and boost coral resilience, we risk the extinction of even more corals from reefs in Florida and worldwide." The Recent Study The new research, featured in the Science journal, analyzed the outcome of staghorn and elkhorn corals off the Florida coast following a severe marine heatwave in 2023. This event raised temperatures on Florida's fraying coral reefs to their peak temperatures in more than a century and a half. The two species are intricate, reef-forming corals and are identified because they resemble, in turn, the antlers of stags and elks. However, scientists who conducted underwater surveys of more than 52,000 colonies of the species, across 391 sites along Florida's coast, found widespread, often devastating, losses. Geographic Effects Along the Florida Keys, mortality rates reached ninety-eight percent and even one hundred percent, showing a complete annihilation of the corals. In southeastern Florida, where temperatures have been cooler, mortality rates were reduced, at about 38%. Historical and Current Dangers The two Acropora species had already suffered from decades of localized impacts in Florida, such as poor water quality from pollutants that wash off the land, as well as disease. But the 2023 marine heatwave has been fatal for these heat-sensitive species. The 2023 heat event caused the ninth occurrence of bleaching on the Florida reef â a process whereby corals become heat-stressed and expel the algae partners living in their tissues, causing them to become bleached white. If temperatures remain elevated, the corals perish entirely. Worldwide Consequences Globally, coral reefs are among the ecosystems most at risk to the human-caused climate crisis. This presents a significant danger to: A quarter of all ocean life that relies upon what are essentially the rainforests of the sea. Millions of people who rely on corals to sustain fish that they can consume and gain an income from. Corals also act as a barrier to protect our shorelines from powerful storms, which are themselves being worsened by rising global temperatures. Preservation Efforts In a desperate attempt to avert a death spiral of threatened corals, scientists have established repositories of Acropora in marine facilities and offshore coral nurseries. Efforts have been undertaken to reseed corals on reefs in Florida, as well, in an effort to regain some of the ninety percent of coral cover lost 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 Expert Commentary "Elkhorn corals, in particular, are some of the most important wave-breaking coral species in the region," noted a study co-author, a marine biologist at the University of Miami. "They used to be abundant on shallow reef tops in the Caribbean, and if we want our reefs to continue protecting our coastlines from inundation during storms, its worth taking extraordinary measures to ensure we don't lose these corals completely."