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Researchers have found that two of the most important coral species comprising Florida's reef have become ecologically extinct following a withering ocean heatwave caused catastrophic losses.

The Meaning Behind '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 are no longer able to play their once vital role in constructing and maintaining reef ecosystems that host a diversity of marine life.

Ecological extinction is a stage before total extinction, a danger that now hangs for many coral species.

Researchers recently alerted that a tipping point has been crossed, meaning corals globally are set to be eradicated due to climate change, which is increasing ocean temperatures to unbearable levels.

Expert Insight

"We're running out of time," stated the lead author of the new Florida study. "Extreme heatwaves are becoming more frequent and intense due to global warming, and without immediate, ambitious actions to reduce ocean heating and boost coral resilience, we risk the disappearance of even more corals from reefs in Florida and around the world."

Details of the New Research

The recent study, published in the journal Science, analyzed the outcome of staghorn and elkhorn coral corals off the Florida coast after a intense marine heatwave in 2023.

This event elevated temperatures on Florida's deteriorating 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 look like, respectively, the horns of stags and elks.

However, researchers who conducted underwater surveys of over fifty-two thousand colonies of the species, across 391 sites along Florida's coast, found widespread, often devastating, losses.

Geographic Effects

• Along the Florida Keys, mortality rates hit 98% and even 100%, showing a complete annihilation of the corals.
• In south-east Florida, where temperatures have been lower, death rates were reduced, at about thirty-eight percent.

Historical and Current Dangers

The two Acropora species had already endured from many years of regional pressures in Florida, such as contaminated water from contaminants that run off the land, as well as disease.

But the 2023 heatwave has been fatal for these heat-sensitive species.

The 2023 event caused the ninth episode of bleaching on the Florida reef – a phenomenon whereby corals become thermally stressed and eject the symbiotic algae living in their tissues, causing them to become ghostly white.

If temperatures remain elevated, the corals perish entirely.

Worldwide Consequences

Worldwide, coral reefs are among the ecosystems most vulnerable to the anthropogenic climate emergency.

This presents a major threat to:

• A quarter of all ocean life that depends on what are effectively the marine rainforests.
• Hundreds of millions of people who depend upon corals to sustain fish that they can consume and earn a livelihood from.

Corals also serve as a barrier to safeguard our shorelines from intense hurricanes, which are themselves being worsened by increasing global heat.

Conservation Efforts

In a last-ditch effort to prevent a decline of endangered corals, scientists have established repositories of Acropora in marine facilities and offshore coral nurseries.

Efforts have been made to replant corals on reefs in Florida, as well, in an effort to restore some of the 90% of coral cover disappeared off the state in the last forty years.

But as global heating continues to intensify, there is little hope of continued existence of these species without significant actions, scientists caution.

Further Expert Commentary

"Elkhorn corals, especially, are some of the most important wave-breaking coral species in the region," said a study co-author, a marine biologist 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 inundation during storms, its worth taking extraordinary measures to ensure we preserve these corals completely."