🔗 Share this article A Pair of Vital Florida Coral Species Deemed 'Functionally Extinct' After Severe Ocean Heatwave Scientists have discovered that two of the key coral species comprising Florida's reef are now functionally extinct after a intense ocean heatwave led to devastating losses. The Meaning Behind 'Functional Extinction' Means The almost complete collapse 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 constructing and maintaining reef ecosystems that host a variety of marine life. Functional extinction is a phase preceding global extinction, a threat that now hangs for many coral species. Scientists this month alerted that a critical threshold has been crossed, whereby corals around the world are likely to be wiped out due to global heating, which is increasing ocean temperatures to intolerable levels. Researcher Insight "Time is running out," said the lead author of the recent research. "Extreme heatwaves are becoming more frequent and intense due to global warming, and absent 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 around the world." The New Research The new research, featured in the Science journal, examined the outcome of staghorn and elkhorn coral 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 over 150 years. The two species are intricate, reef-forming corals and are identified because they resemble, in turn, the antlers of male deer and elks. However, researchers who performed diver surveys of more than 52,000 colonies of the species, across 391 sites along Florida's coast, found extensive, often catastrophic, losses. Regional Impact In the Florida Keys, death rates reached 98% and even one hundred percent, showing a total eradication of the corals. In south-east Florida, where temperatures have been cooler, mortality rates were lower, at about thirty-eight percent. Past and Current Dangers The two Acropora species had already endured from decades of regional pressures in Florida, such as contaminated water from pollutants that run off the land, as well as disease. But the 2023 heatwave has proved lethal for these temperature-sensitive species. The 2023 event caused the ninth occurrence of bleaching on the Florida reef – a phenomenon whereby corals become heat-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 Worldwide, coral reefs are among the ecosystems most vulnerable to the anthropogenic climate emergency. This poses a significant danger to: A quarter of all ocean life that relies upon what are effectively the rainforests of the sea. Hundreds of millions of people who rely on corals to support fish that they can eat and gain an income from. Corals also act as a protective barrier to protect our shorelines from intense hurricanes, which are themselves being intensified by increasing global heat. Preservation Attempts In a last-ditch effort to avert a death spiral of threatened corals, scientists have established repositories of Acropora in aquariums and ocean-based nurseries. Attempts have been undertaken to reseed corals on reefs in Florida, as well, 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 intensify, there is little hope of long-term survival of these species without major interventions, scientists caution. Further Researcher Insight "Elkhorn corals, in particular, are some of the most important wave-dampening coral species in the area," said a study co-author, a ocean scientist at the University of Miami. "They were once common 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 altogether."