Explorers discover ‘unrivaled’ reef of rose-shaped corals that could hold lessons for warming oceans

Photos released by the team showed a seabed covered with rose-shaped corals — some of them more than 6 feet (2 meters) in diameter.

Whereas many of the world’s explored tropical reefs are found in relatively shallow water, the Tahiti corals stunned the exploration team because they live far deeper, in areas that remain largely unexplored.

“The fact that we are finding a very healthy and pristine coral reef at depths of 30 to 70 meters (98 to 230 feet) is quite unusual,” said UNESCO marine policy official Julian Barbière, adding that the discovery may have implications that go beyond Tahiti.

“There could be all those reefs out there that have not been mapped or studied,” he said.

Only 20 percent of the world’s seabed has been mapped in high-resolution, he said, and UNESCO has supported efforts to study the unexplored parts.

“To date, we know the surface of the moon better than the deep ocean,” UNESCO Director General Audrey Azoulay said in a release. The U.N. agency wants to support a series of ocean expeditions over the course of this decade.

The expedition that led to the exploration of the Tahiti reef was headed by a team of explorers that included photographer Alexis Rosenfeld and France’s CNRS-CRIOBE research center. UNESCO supported the mission.

Barbière said the discovery could yield important lessons on how to protect coral reefs, as global warming is driving a rise in the number of havoc-wreaking bleaching events.

In 2019, coral reefs off Tahiti went through a dramatic bleaching episode, with researchers estimating that up to two thirds of corals were impacted within days. Corals located in shallow water were hit particularly hard.

But during their expedition last year, the French team found no major evidence of destruction at the deeper reef that had not been explored up until that point.

While corals that are found at greater depth may be less vulnerable to global warming, a lack of sunlight poses different challenges there.

UNESCO official Barbière said one of the key questions going forward will be to understand not only how the Tahiti reef is “in such good condition” but also “how such coral reefs can grow in this twilight zone of the ocean.”

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