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Researchers have found that two of the primary coral species comprising Florida's reef have become ecologically extinct following a intense ocean heatwave led to catastrophic losses.

The Meaning Behind 'Functional Extinction' Means

The almost complete decline of these corals, which once formed the backbone of reefs in Florida and the Caribbean, means they can no longer fulfill their once vital role in constructing and maintaining reef ecosystems that support a variety of marine life.

Functional extinction is a phase before global extinction, a threat that now hangs for many coral species.

Researchers this month alerted that a critical threshold has been crossed, meaning corals around the world are set to be eradicated due to climate change, which is increasing ocean temperatures to unbearable levels.

Expert Insight

"Time is running out," stated the lead author of the recent research. "Extreme heatwaves are becoming more frequent and intense due to global warming, and without swift, decisive measures to slow ocean warming and enhance coral survival, we risk the extinction of even more corals from reefs in Florida and around the world."

Details of the Recent Study

The new research, published in the journal Science, examined the fate of staghorn coral and elkhorn coral corals off the Florida coast after a severe marine heatwave in 2023.

This event elevated 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 horns of male deer 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 extensive, often devastating, losses.

Regional Impact

• In the Florida Keys, death rates reached ninety-eight percent and even 100%, revealing a complete annihilation of the corals.
• In southeastern Florida, where temperatures have been cooler, death rates were reduced, at about thirty-eight percent.

Past and Current Threats

The two Acropora species had already endured from decades of regional pressures in Florida, such as contaminated water from pollutants that wash off the land, as well as illness.

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

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

If temperatures stay high, the corals perish entirely.

Worldwide Consequences

Worldwide, coral reefs are among the ecosystems most at risk to the anthropogenic climate crisis.

This presents a major threat to:

• One-fourth of all ocean life that depends on what are essentially the rainforests of the sea.
• Hundreds of millions of people who rely on corals to sustain fish that they can consume and earn a livelihood from.

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

Preservation Efforts

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

Efforts have been undertaken to reseed corals on reefs in Florida, too, in an effort to regain 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 little hope of long-term survival of these species absent significant actions, scientists caution.

Further Expert Commentary

"Elkhorn corals, especially, are some of the key wave-dampening coral species in the region," noted Andrew Baker, a marine biologist at the University of Miami.

"They used to be abundant 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."