Scientists in Florida have launched an emergency effort to protect one of the Caribbean’s most important reef-building corals from disappearing altogether. Researchers at the University of Miami have transported 30 fragments of endangered elkhorn coral from underwater nurseries to a land-based hatchery, fearing that another intense marine heatwave this summer could trigger widespread coral bleaching. The move comes after successive heatwaves in 2023 and 2024 devastated Florida’s coral reefs, leaving elkhorn coral functionally extinct across much of South Florida. By bringing the coral ashore, scientists hope to preserve its remaining genetic diversity until ocean conditions become safe enough for future restoration efforts.
Florida scientists move endangered elkhorn coral ashore as heatwave threat grows
The emergency relocation was carried out by researchers from the University of Miami, who have been cultivating endangered elkhorn coral in offshore nurseries for years. However, forecasts of unusually warm ocean temperatures this summer have raised fears that another severe bleaching event could destroy even these carefully managed populations.Marine biologist Diego Lirman, an associate professor at the University of Miami, said early signs suggest 2026 could become an especially difficult year for Florida’s corals. Some corals have already begun showing signs of heat stress, prompting scientists to act before temperatures climb further.Divers collected 30 genetically diverse coral fragments, wrapped each piece in wet bubble wrap to prevent dehydration and transported them in insulated coolers to the university’s hatchery. Once there, the corals were sanitised and placed into specially maintained tanks where water temperature, salinity and other conditions can be closely controlled.
What is elkhorn coral and why does it matter?
Elkhorn coral (Acropora palmata) is one of the most important reef-building coral species found in the Caribbean and the waters surrounding Florida. Named for its broad branches that resemble the antlers of an elk, it grows relatively quickly and forms large reef structures in shallow coastal waters.These reefs provide habitat for countless marine species, support commercial and recreational fisheries, attract tourists and act as natural barriers that absorb wave energy during storms and hurricanes. Although coral reefs cover less than one per cent of the ocean floor, they support around a quarter of all known marine species at some stage of their lives.Because of its ecological importance and dramatic decline, elkhorn coral is listed as critically endangered by the International Union for Conservation of Nature and is protected under the US Endangered Species Act.
Why coral bleaching is becoming a growing threat
Coral bleaching occurs when prolonged periods of unusually warm seawater place corals under stress. Healthy corals live in partnership with microscopic algae called zooxanthellae, which provide them with most of their food through photosynthesis and give reefs their vibrant colours.When water temperatures rise beyond what corals can tolerate, they expel these algae and turn white, a process known as bleaching. Bleached corals are not immediately dead, but if stressful conditions continue for weeks, they lose their primary food source and often die.Florida has experienced four mass bleaching events within the past decade, with little time between them for reefs to recover. Researchers say repeated marine heatwaves linked to climate change are making these events more frequent and more severe.
What ‘functionally extinct’ means for Florida’s reefs
Scientists say elkhorn coral has become functionally extinct across much of South Florida, stretching from Broward County to the Florida Keys.Functionally extinct does not mean every coral colony has disappeared. Instead, so few colonies remain, and they are so widely separated, that they can no longer reproduce naturally in numbers sufficient to restore healthy populations.The devastating marine heatwave of 2023 caused widespread coral mortality, while another, although less severe, bleaching event in 2024 further weakened the remaining populations. Researchers now fear another exceptionally hot summer could eliminate many of the surviving colonies if no protective measures are taken.
Preserving genetic diversity for future restoration
One of the main goals of relocating the coral is to preserve as much genetic diversity as possible. Every coral fragment carries unique genetic traits that could prove crucial for the species’ long-term survival.Some corals may naturally tolerate higher temperatures, while others could possess greater resistance to disease or ocean acidification. Losing those genetic traits would make future restoration significantly more difficult.To reduce that risk, the University of Miami exchanges coral fragments with other research institutions, aquariums and conservation facilities. Maintaining genetically diverse collections at multiple locations ensures that a single disease outbreak or environmental disaster cannot wipe out the remaining breeding stock.
How coral nurseries are helping restore reefs
Over the past decade, Florida scientists have developed underwater coral nurseries to help rebuild damaged reefs. Small coral fragments are attached to underwater frames or suspended structures where they grow under monitored conditions before being transplanted back onto natural reefs.Thousands of coral colonies have already been restored using this technique, although repeated marine heatwaves continue to threaten those gains.The temporary transfer of some coral fragments to land represents an additional layer of protection during periods of extreme ocean warming. Researchers hope the rescued colonies can eventually be returned to the sea once environmental conditions improve.
Climate change is increasing the urgency
Scientists say rising global temperatures are warming the oceans, increasing both the frequency and intensity of marine heatwaves. Unlike isolated bleaching events seen decades ago, today’s heatwaves are occurring so often that corals have little opportunity to recover before facing the next episode.According to the University of Miami researchers, the bleaching seasons are beginning to overlap, leaving coral reefs under almost continuous stress. If this trend continues, more reef-building coral species could face severe population declines despite ongoing restoration efforts.
