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Researchers have found that two of the key coral species comprising Florida's reef are now functionally extinct following a withering ocean heatwave caused devastating losses.

The Meaning Behind 'Functional Extinction' Means

The near-total collapse 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 support a variety of marine life.

Functional extinction is a phase before total extinction, a threat that now looms for many coral species.

Scientists recently warned that a critical threshold had been reached, meaning corals around the world are set to be eradicated due to climate change, which is increasing ocean temperatures to intolerable levels.

Researcher Insight

"We're running out of time," stated Ross Cunning of the recent research. "Severe marine heatwaves are becoming more frequent and intense due to climate change, and absent immediate, ambitious actions to slow ocean warming and enhance coral survival, we face the danger of the extinction of even more corals from reefs in Florida and worldwide."

Details of the Recent Study

The recent study, featured in the Science journal, analyzed the fate of staghorn coral and elkhorn coral corals off the Florida coast following 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, in turn, the antlers of male deer and elk.

However, researchers who performed underwater surveys of over fifty-two thousand colonies of the species, across nearly four hundred sites along Florida's coast, found widespread, often catastrophic, losses.

Geographic Impact

• In the Florida Keys, death rates reached 98% and even 100%, showing a total eradication of the corals.
• In south-east Florida, where temperatures have been lower, mortality rates were lower, 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 poor water quality from contaminants that run off the land, as well as disease.

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

The 2023 event caused the ninth occurrence of bleaching on the Florida reef – a process whereby corals become heat-stressed and expel the symbiotic algae living in their tissues, causing them to become ghostly white.

If temperatures stay high, the corals perish completely.

Worldwide Implications

Worldwide, coral reefs are among the ecosystems most at risk to the human-caused climate crisis.

This poses a major threat to:

• A quarter of all ocean life that relies upon what are effectively the marine rainforests.
• Hundreds of millions of people who depend upon corals to sustain fish that they can eat and gain an income from.

Corals also serve as a protective barrier to protect our shorelines from intense hurricanes, which are themselves being intensified by rising global temperatures.

Preservation Efforts

In a last-ditch effort to prevent a decline of threatened corals, scientists have established collections of Acropora in marine facilities and ocean-based nurseries.

Efforts have been made 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 Expert Commentary

"Elkhorn species, especially, are some of the most important wave-breaking coral species in the region," said Andrew Baker, 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 keep safeguarding our coastlines from flooding during storms, it is worthwhile taking exceptional steps to ensure we preserve these corals altogether."