Giant healthy rose-shaped coral reef discovered off Tahiti

This is an important discovery, as coral reefs suffer from climate change. Scientists have unearthed a healthy, rose-shaped giant coral reef more than 30 meters deep off Tahiti. “It is one of the largest coral reefs in the world to be more than 30 meters deep”, specifies in a press release Unesco, which supports this scientific mission. “The immaculate condition of the rose-shaped corals and the extent of the area they cover make this a very unusual find”, underlines the organization.

The reef extends over three kilometers long and between 30 and 65 meters wide, between 35 and 70 meters deep, adds Unesco. Some giant corals are two meters in diameter. “It’s a little explored area. What we know well are the areas between zero and 30 meters”, explains Laetitia Hedouin, marine biologist and coral specialist, from the French CNRS research center and the environmental research organization Criobe.

“These corals do not show signs of stress or disease”, she continues, while corals located closer to the surface in French Polynesia experienced a bleaching episode in 2019. Starfish can also ravage corals by devouring them.

The diving expedition took place in November 2021, thanks to specific diving equipment to go down that far. “The team made dives totaling around 200 hours to study the reef and were able to witness the spawning of the coral”, says Unesco.

Temperature sensors have been placed in the area. “We are at the start of a monitoring program that we hope will be long term”, to better understand why this coral reef has visibly not suffered from climate change and what its population dynamics are. This finding also raises the question of “the taking into account of these deep zones in the development of marine protected areas”, emphasizes Laetitia Hedouin. As Unesco reminds us, the state of knowledge of the oceans is still limited, “with only 20% of the planet’s seabed (…) mapped”.