The coral that beat climate change — and us
Scientists have explored a rare stretch of pristine corals shaped like roses off the coast of Tahiti. The reef is thought to be one of the largest found at such depths and seems untouched by climate change or human activities.
Laetitia Hedouin said she first saw the corals during a recreational dive months earlier.
“When I went there for the first time, I thought, ‘Wow — we need to study that reef. There’s something special about that reef ’,” said Hedouin, a researcher at the French National Centre for Scientific Research in Moorea, French Polynesia.
What struck Hedouin was that the corals looked healthy and weren’t affected by a bleaching event in 2019.
Corals are tiny animals that grow and form ocean reefs. Globally, coral reefs have been depleted from overfishing and pollution. Climate change is also harming delicate corals, with severe bleaching caused by warmer waters. Between 2009 and 2018,
14 per cent of the world’s corals were killed, according to a 2020 report by the Global Coral Reef Monitoring Project.
The newfound reef, stretching
3km, was studied late last year during a dive expedition supported by Unesco. Unlike most of the world’s mapped corals, which are found in relatively shallow waters, this one was deeper — between 35 and 70m.
Exploring such depths posed a challenge: the deeper a diver goes underwater, the shorter amount of time can be safely spent at each depth.
The team was equipped with special tanks and did 200 hours of diving to study the reef, including taking photographs, measurements and coral samples.
The reef is in a spot where many researchers haven’t spent a lot of time, former National Oceanic and Atmospheric Administration oceanographer Mark Eakin said.
“We’ll be seeing more of these discoveries as the technology is applied to these locations,” said Eakin. “We may find some bigger ones somewhere, but I think this is always going to be an unusual reef.”
The recent volcanic eruption in Tonga that triggered tsunami waves had not affected the reef off Tahiti, Hedouin said.
Hdouin hopes the research can help experts understand how the reef has been resilient to climate change and human pressures, and what role these deeper corals might play in the ocean ecosystem.
More dives are planned in the coming months.
“We know very little about the ocean, and there’s still so much that needs to be recorded, needs to be measured,” said Julian Barbiere, the head of Unesco’s marine policy and regional coordination.