🔗 Share this article A Pair of Crucial Florida Coral Species Declared 'Functionally Extinct' Following Severe Ocean Heatwave Researchers have found that two of the primary coral species forming Florida's reef are now functionally extinct after a withering ocean heatwave caused devastating 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 can no longer fulfill their previously crucial role in building and sustaining reef ecosystems that host a variety of marine life. Functional extinction is a phase preceding global extinction, a danger that now hangs for many coral species. Researchers this month alerted that a critical threshold had been reached, whereby corals around the world are likely to be eradicated due to global heating, which is increasing ocean temperatures to intolerable levels. Expert Perspective "Time is running out," stated Ross Cunning of the new Florida study. "Extreme heatwaves are increasing in frequency and severity due to climate change, and absent swift, decisive measures to reduce ocean heating and boost coral resilience, we face the danger of the disappearance of even more corals from reefs in Florida and around the world." Details of the Recent Study The recent study, featured in the Science journal, analyzed the outcome of staghorn and elkhorn corals off the Florida coast following a intense marine heatwave in 2023. This event raised temperatures on Florida's fraying coral reefs to their highest levels in more than a century and a half. The two species are complex, reef-forming corals and are named because they resemble, respectively, the antlers of stags and elk. However, researchers who conducted diver surveys of more than 52,000 colonies of the species, across nearly four hundred sites along Florida's coast, found extensive, often catastrophic, losses. Regional Effects Along the Florida Keys, death rates hit ninety-eight percent and even 100%, showing a total eradication of the corals. In south-east Florida, where temperatures have been lower, death rates were lower, at about thirty-eight percent. Past and Current Threats The two Acropora species had already suffered from many years of regional pressures in Florida, such as contaminated water from pollutants that wash 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 coral bleaching on the Florida reef – a process whereby corals become thermally stressed and expel the symbiotic algae living in their tissues, causing them to become ghostly white. If temperatures stay high, the corals die off entirely. Worldwide Implications Worldwide, 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 effectively the rainforests of the sea. Millions of people who depend upon corals to support fish that they can consume and earn a livelihood from. Corals also serve 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 created collections of Acropora in marine facilities and offshore coral nurseries. Efforts have been undertaken to reseed corals on reefs in Florida, too, in an effort to restore some of the ninety percent of coral cover disappeared off the state in the last forty years. But as climate change continues to escalate, there is slim chance of long-term survival of these species without major interventions, researchers warn. Further Researcher Insight "Elkhorn species, especially, are some of the most important wave-breaking coral species in the area," noted Andrew Baker, a ocean scientist at the University of Miami. "They used to be common on shallow reef crests 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 don't lose these corals completely."