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Researchers have found that two of the primary coral species forming Florida's reef are now ecologically extinct after a withering ocean heatwave led to catastrophic losses.

The Meaning Behind 'Functional Extinction' Means

The near-total collapse of these corals, which once served as the foundation of reefs in Florida and the Caribbean, indicates they can no longer fulfill their previously crucial role in constructing and maintaining reef ecosystems that host a variety of marine life.

Ecological extinction is a stage preceding total extinction, a danger that now looms for many coral species.

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

Researcher Perspective

"We're running out of time," said the lead author of the recent research. "Extreme heatwaves are becoming more frequent and intense due to global warming, and without immediate, ambitious actions to slow ocean warming and enhance coral survival, we risk the disappearance of even more corals from reefs in Florida and around the world."

The Recent Study

The new research, featured in the Science journal, examined 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 deteriorating coral reefs to their highest levels in more than a century and a half.

The two species are intricate, reef-forming corals and are named because they resemble, respectively, the horns of stags and elk.

However, scientists who performed diver surveys of more than 52,000 colonies of the species, across nearly four hundred sites along Florida's coast, found widespread, often catastrophic, losses.

Regional Effects

• In the Florida Keys, mortality rates hit ninety-eight percent and even 100%, revealing a complete annihilation of the corals.
• In southeastern Florida, where temperatures have been lower, death rates were lower, 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 contaminants that run off the land, as well as illness.

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

The 2023 event caused the ninth episode of coral 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 ghostly white.

If temperatures stay high, the corals perish entirely.

Global Consequences

Globally, 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 relies upon what are essentially the rainforests of the sea.
• 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 powerful storms, which are themselves being worsened by rising global temperatures.

Preservation Attempts

In a desperate attempt to prevent a death spiral of endangered corals, scientists have established collections of Acropora in aquariums and offshore coral nurseries.

Attempts have been made to replant corals on reefs in Florida, as well, in an effort to regain some of the ninety percent of coral cover lost off the state in the past four decades.

But as climate change continues to escalate, there is slim chance of continued existence of these species without significant actions, scientists caution.

Additional Researcher Insight

"Elkhorn species, in particular, are some of the key wave-breaking coral species in the area," noted a study co-author, a ocean scientist at the Miami University.

"They were once abundant on shallow reef tops in the Caribbean, and if we want our reefs to continue protecting our coastlines from flooding during storms, its worth taking extraordinary measures to ensure we don't lose these corals altogether."