'Remarkable' giant coral reef with rose-shaped corals found off Tahiti
The rose-shaped corals were found to be healthy Alexis ROSENFELD Alexis Rosenfeld/AFP/File

Scientists have discovered one of the world's largest coral reefs off the coast of Tahiti, a vast area of "pristine" rose-shaped corals deep under water apparently unharmed by climate change, UNESCO announced Thursday.

The area of healthy coral in cooler waters between 30 and 65 meters (98 to 213 feet) deep is a "highly unusual" find, UNESCO said, and could suggest there are more reefs in the ocean depth that may be safer from the impacts of warming waters.

"The discovery of this reef in such a pristine condition is good news and can inspire future conservation," said Laetitia Hedouin, a marine biologist at French research agency (CNRS).

"We think that deeper reefs may be better protected from global warming."

The reef is approximately three kilometers (two miles) in length and up to 65 meters wide in places, which UNESCO said "makes it one of the most extensive healthy coral reefs on record".

Most of the world's known reefs have been found at depths of up to 25 meters and the UN heritage body said the Tahiti reef could suggest there are more areas of healthy coral in the ocean's unmapped "twilight zone".

"To date, we know the surface of the moon better than the deep ocean," said UNESCO Director-General Audrey Azoulay, adding that only 20 percent of the world's seabed had been mapped.

"This remarkable discovery in Tahiti demonstrates the incredible work of scientists who, with the support of UNESCO, further the extent of our knowledge about what lies beneath."

French Polynesia suffered a significant bleaching event back in 2019 however this reef does not appear to have been significantly affected.

The giant rose-shaped corals are each up to two meters in diameter.

"These corals do not show signs of stress or disease," Hedouin told AFP.

Bleaching occurs when healthy corals become stressed by spikes in ocean temperatures, causing them to expel algae living in their tissues, leaving graveyards of bleached skeletons where vibrant ecosystems once thrived.

© 2022 AFP