A huge, “pristine” coral reef has been discovered off the coast of Tahiti, French Polynesia. Stretching 3 kilometers (nearly 2 miles) – that’s around 27 football fields – it is thought to be one of the biggest coral reefs in the world.
It is also one of the healthiest, which the scientists who discovered it as part of UNESCO’s ocean mapping initiative attribute to the great depth at which it was found. Most of the world’s known reefs are at depths of up to 25 meters (82 feet), whereas the newest member is located between 30 and 65 meters (98 to 213 feet) below the ocean’s surface. The extra few meters, the team believes, could be protecting it from bleaching caused by global warming.
Known as the “twilight zone”, this area of deep ocean is rarely studied, making it a potential untapped resource for discovering coral reefs, which the team hopes can be explored in future.
“To date, we know the surface of the Moon better than the deep ocean. Only 20 percent of the entire seabed has been mapped,” Audrey Azoulay, UNESCO Director-General, said in a statement.
"This remarkable discovery in Tahiti... [will] further the extent of our knowledge about what lies beneath."
The rose-shaped corals discovered in November are each around 2 meters (7 feet) in diameter and are primarily one of two species: Porites rus dominates the upper portion and Pachyseris speciosa the lower, according to New Scientist.
It took UNESCO’s team of international divers a total of 200 hours to study the vast reef, but their toil seems to have paid off.
“It was magical to witness giant, beautiful rose corals which stretch for as far as the eye can see. It was like a work of art,” Alexis Rosenfeld, a French photographer who was part of the team of divers that made the discovery, said.
Findings such as this are vital for research, as coral reefs are an important food source and home to a large number of organisms, meaning they can tell us a lot about biodiversity. They also provide protection against coastal erosion and even tsunamis, and the variety of organisms that live there can be important for medicinal research.
Sadly, they are one of the ocean’s most threatened ecosystems, vulnerable to the effects of global warming: rising sea temperatures, pollution, and increased carbon dioxide levels.
“As shallow waters warm faster than the deeper waters we may find these deeper reef systems are refuges for corals in the future. We need to get out there to map these special places, understand their ecological role and make sure we protect them for the future,” Professor Murray Roberts, a leading marine scientist from the University of Edinburgh, told the BBC.