🔗 Share this article A Pair of Vital Florida Coral Species Deemed 'Functionally Extinct' Following Severe Ocean Heatwave Researchers have found that two of the key coral species comprising Florida's reef have become ecologically extinct following a intense ocean heatwave caused devastating losses. What 'Functional Extinction' Signifies The near-total collapse of these corals, which once served as the backbone of reefs in Florida and the Caribbean, indicates they can no longer play their once vital role in building and sustaining reef ecosystems that host a diversity of marine life. Functional extinction is a stage before total extinction, a danger that now looms for many coral species. Scientists this month alerted that a tipping point has been crossed, whereby corals around the world are likely to be eradicated due to climate change, which is raising ocean temperatures to intolerable levels. Expert Insight "Time is running out," stated the lead author of the new Florida study. "Extreme heatwaves are increasing in frequency and severity due to global warming, and absent immediate, ambitious actions to reduce ocean heating and enhance coral survival, we face the danger of the extinction of additional coral species from reefs in Florida and around the world." The New Research The new research, featured in the Science journal, examined the outcome of staghorn coral and elkhorn coral corals off the Florida coast after a intense marine heatwave in 2023. This event raised temperatures on Florida's deteriorating coral reefs to their highest levels in more than a century and a half. The two species are intricate, reef-forming corals and are named because they look like, in turn, the horns of stags and elks. However, scientists who conducted underwater 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, mortality rates hit 98% and even 100%, showing a total eradication of the corals. In south-east Florida, where temperatures have been lower, death rates were reduced, at about thirty-eight percent. Past and Current Dangers 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 disease. But the 2023 marine heatwave has been fatal for these temperature-sensitive species. The 2023 heat event caused the ninth episode of coral bleaching on the Florida reef – a phenomenon whereby corals become heat-stressed and expel the algae partners living in their tissues, causing them to become bleached white. If temperatures stay high, the corals die off entirely. Global Consequences Worldwide, coral reefs are among the ecosystems most at risk to the human-caused climate crisis. This poses a significant danger to: One-fourth of all ocean life that relies upon what are essentially the marine rainforests. Millions of people who depend upon corals to support fish that they can consume and earn a livelihood from. Corals also act as a barrier to protect our shorelines from powerful storms, which are themselves being intensified by increasing global heat. Preservation Attempts In a desperate attempt to prevent a decline of threatened corals, scientists have established collections of Acropora in aquariums and offshore coral nurseries. Attempts 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 global heating continues to intensify, there is slim chance of long-term survival of these species without major interventions, scientists caution. Additional Expert Commentary "Elkhorn corals, especially, are some of the key wave-dampening coral species in the area," noted a study co-author, a marine biologist at the University of Miami. "They used to be common on shallow reef tops in the Caribbean, and if we want our reefs to continue protecting our coastlines from flooding during storms, its worth taking exceptional steps to ensure we don't lose these corals completely."