A large and rare coral reef in excellent health was found in Tahiti by a UNESCO mission. The finding is surprising, considering that corals are not expected to be found in areas as deep as this one, at more than 30 meters deep.
“It’s a positive story about coral reefs,” he tells leaf Julian Barbiere, head of marine policy at UNESCO. “That doesn’t happen often these days,” he says, highlighting the loss of about half of the world’s coral reefs since 1950.
The reef —which are animals, it is worth remembering— found is about 3 km long, with widths between 30 and 65 meters. The corals are shaped like giant roses, some reaching 2 meters in diameter. In addition to the flashy size, the good conditions of the coral stand out.
According to UNESCO, it is one of the largest coral reefs ever observed in the ocean area known as the twilight zone, which represents ocean depths ranging from 30 to 120 meters – which still have some light and, in this way, allow the development of corals, which are living beings.
Most commonly, corals are found at depths of up to 25 meters.
Barbiere says the discovery — made possible by advances in diving equipment, which allow for longer and deeper exploration — suggests that there may be even more undiscovered corals at greater depths.
Laetitia Hédouin, a researcher on the expedition and a scientist at the CNRS (a scientific research center in France), points out that corals in the region where the new reef was found suffered a significant bleaching event in 2019.
“This reef does not appear to have been significantly affected. We believe that deeper reefs may be better protected from climate change,” says Hédouin.
The discovery also shows how little humans know about the ocean, says Barbiere. “Our work at UNESCO is to facilitate the discovery of this type of ecosystem, but also, by learning that it exists, to help countries implement protection measures, for example from marine protected areas.”
Corals are of great importance to marine biodiversity. According to estimates, around 25% of the ocean’s fish species depend on these living structures. Countless animals feed, reproduce and find shelter in corals.
These living beings, therefore, become important for tourism, for fishing, in addition to preventing coastal erosion by waves and storms, and absorbing carbon.
The big problem is that corals are under severe threat, mainly because of climate change. Temperature rises cause stress and bleaching events — which can lead to death. In bleaching, in general, corals lose the photosynthetic algae that produce food.
According to UNEP (United Nations environmental program), all corals in the world can be bleached by the end of the century. The world’s longest bleaching event is recent. It took place from 2014 to 2017.
The mission took place as part of the UN Decade of Ocean Science for Sustainable Development. The researchers spent about 200 hours studying the corals at the site.
In addition to Hédouin, French photographer Alexis Rosenfeld, who is dedicated to ocean exploration through the Unesco-supported 1 Ocean campaign, led the team of divers, which also included researchers from the environmental research group Criobe.
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