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Researchers have found that two of the primary coral species comprising Florida's reef have become 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, indicates they are no longer able to fulfill their previously crucial role in building and sustaining reef ecosystems that host a diversity of marine life.

Functional extinction is a stage before global extinction, a danger that now hangs for many coral species.

Scientists recently warned that a tipping point has been crossed, meaning corals around the world are likely to be wiped out due to climate change, which is raising ocean temperatures to intolerable levels.

Expert Insight

"Time is running out," stated the lead author of the recent research. "Extreme heatwaves are increasing in frequency and severity due to global warming, and absent immediate, ambitious actions to reduce ocean heating and enhance coral survival, we face the danger of the extinction of even more corals from reefs in Florida and around the world."

Details of the New Research

The recent study, published in the Science journal, examined the fate of staghorn 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 peak temperatures in over 150 years.

The two species are complex, reef-building corals and are identified because they resemble, respectively, the antlers of stags and elk.

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

Regional Effects

• In the Florida Keys, death rates hit 98% and even 100%, showing a total eradication of the corals.
• In southeastern 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 endured from many years of localized impacts in Florida, such as contaminated water from pollutants that run off the land, as well as disease.

But the 2023 heatwave has proved lethal for these temperature-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 algae partners living in their tissues, causing them to become ghostly white.

If temperatures stay high, the corals die off completely.

Global Consequences

Globally, coral reefs are among the ecosystems most vulnerable to the anthropogenic climate emergency.

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 support fish that they can consume and gain an income from.

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

Conservation Attempts

In a desperate attempt to prevent a decline of threatened corals, scientists have created repositories of Acropora in aquariums and ocean-based nurseries.

Efforts have been undertaken to replant corals on reefs in Florida, too, in an effort to restore 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 slim chance of continued existence 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," noted a study co-author, a ocean scientist at the University of Miami.

"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 preserve these corals completely."