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Researchers have found that two of the key coral species forming Florida's reef have become ecologically extinct after a intense ocean heatwave caused devastating losses.

The Meaning Behind '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 fulfill their once vital role in building and sustaining reef ecosystems that host a variety of marine life.

Ecological extinction is a stage preceding global extinction, a threat that now hangs for many coral species.

Researchers recently alerted that a tipping point has been crossed, whereby corals globally are likely to be eradicated due to global heating, which is increasing ocean temperatures to unbearable levels.

Expert 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 global warming, and absent swift, decisive measures to slow ocean warming and enhance coral survival, we risk the extinction of additional coral species from reefs in Florida and worldwide."

Details of the Recent Study

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

This event raised temperatures on Florida's deteriorating coral reefs to their highest levels in over 150 years.

The two species are complex, reef-building corals and are named because they resemble, in turn, the horns of stags and elk.

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

Geographic Impact

• Along the Florida Keys, mortality rates hit 98% and even one hundred percent, revealing a total eradication of the corals.
• In south-east Florida, where temperatures have been cooler, mortality rates were lower, at about thirty-eight percent.

Past and Current Dangers

The two Acropora species had already suffered from decades of regional pressures in Florida, such as contaminated water from contaminants 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 bleaching on the Florida reef – a process whereby corals become heat-stressed and eject the symbiotic algae living in their tissues, causing them to become bleached white.

If temperatures remain elevated, the corals die off completely.

Global Implications

Globally, coral reefs are among the ecosystems most vulnerable to the human-caused climate crisis.

This presents a major threat to:

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

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

Conservation Efforts

In a last-ditch effort to prevent a death spiral of endangered corals, scientists have established repositories of Acropora in aquariums and offshore coral 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 lost off the state in the last forty years.

But as global heating continues to escalate, there is little hope of long-term survival of these species without significant actions, researchers warn.

Further Expert Commentary

"Elkhorn corals, in particular, are some of the key wave-breaking coral species in the region," noted Andrew Baker, a ocean scientist 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 inundation during storms, it is worthwhile taking exceptional steps to ensure we preserve these corals completely."