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Researchers have found that two of the most important coral species forming Florida's reef are now ecologically extinct following a intense ocean heatwave caused catastrophic losses.

The Meaning Behind 'Functional Extinction' Means

The near-total collapse of these corals, which once formed the backbone of reefs in Florida and the Caribbean, means they are no longer able to fulfill their once vital role in building and sustaining reef ecosystems that support a diversity of marine life.

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

Scientists recently alerted that a tipping point has been crossed, meaning corals around the world are set to be eradicated due to climate change, which is raising ocean temperatures to unbearable levels.

Expert Insight

"Time is running out," stated the lead author of the recent research. "Severe marine heatwaves are becoming more frequent and intense due to global warming, and absent swift, decisive measures to reduce ocean heating and enhance coral survival, we risk the disappearance of additional coral species from reefs in Florida and worldwide."

The New Research

The new research, featured in the journal Science, analyzed the outcome of staghorn coral and elkhorn coral corals off the Florida coast following a intense marine heatwave in 2023.

This event raised temperatures on Florida's fraying coral reefs to their peak temperatures in over 150 years.

The two species are complex, reef-forming corals and are named because they look like, respectively, the horns of male deer and elk.

However, scientists who conducted diver surveys of more than 52,000 colonies of the species, across 391 sites along Florida's coast, found widespread, often devastating, losses.

Regional Impact

• Along the Florida Keys, mortality rates reached 98% and even 100%, showing a total eradication of the corals.
• In southeastern Florida, where temperatures have been lower, death rates were reduced, at about thirty-eight percent.

Past and Present Dangers

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

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

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

If temperatures stay high, the corals perish completely.

Global Implications

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

This presents a significant danger to:

• One-fourth of all ocean life that relies upon what are essentially the marine rainforests.
• Millions of people who rely on corals to sustain fish that they can eat and gain an income from.

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

Conservation Efforts

In a last-ditch effort to avert a decline of endangered corals, scientists have created 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 climate change continues to intensify, there is slim chance of long-term survival of these species without major interventions, researchers warn.

Further Expert Commentary

"Elkhorn corals, in particular, are some of the key wave-breaking coral species in the region," said Andrew Baker, a ocean scientist at the Miami University.

"They used to be common on shallow reef crests in the Caribbean, and if we want our reefs to keep safeguarding our coastlines from flooding during storms, its worth taking exceptional steps to ensure we don't lose these corals altogether."