An underwater mapping project recently took an unexpected turn off the coast of Tahiti, where deep-sea explorers this week said they’d discovered a vast coral reef resembling a bed of roses that appeared largely unscathed by climate change.
The reef, which stretches for about two miles, is remarkably well-preserved and is among the largest ever found at its depth, according to those involved in the mapping project sponsored by the United Nations Educational Organization (UNESCO) science and culture.
Some even described the condition of the reef, hidden at depths between 30 meters (about 100 feet) and 100 meters in the crystal clear waters of the South Pacific, as “pristine”.
Alexis Rosenfeld, an underwater photographer from Marseille, France, said Thursday that the reef lived up to what he envisioned when he first explored it shortly after its discovery in November.
“This, my dream, is exactly like the reality,” Mr Rosenfeld said of the reef, which is about two kilometers offshore.
Rosenfeld, 52, photographed the reef as part of a deep-sea exploration project called 1 Ocean, in collaboration with UNESCO and researchers at CRIOBE, a leading French laboratory specializing in the study of coral reef ecosystems., and the French National Center for Scientific Research.
The reef occupies part of the ocean known as the mesophotic zone — from the Greek words for middle and light — where the algae that coral depends on for survival can still grow, but where light penetration is significantly reduced, scientists say. .
Unlike coral reefs found at shallower depths, which are often shaped like branches and more susceptible to damage from rising ocean temperatures, scientists said, mesophotic reefs shape their flower shape to gain more surface area and receive more light. To take pictures in low light, said Mr. Rosenfeld that he was using a Sony Alpha 1, a mirrorless full-frame camera.
Julian Barbara, head of the Marine Policy and Regional Coordination Division of the Intergovernmental Oceanographic Commission at UNESCO, said on Thursday that he was blown away by the expanse of rose petals captured in the photos.
“You can see them as far as the eye can see,” he said. “When they came back and showed the pictures, we were really amazed at the quality of the ecosystem there.”
Mr. Barbara noted that climate change poses a significant threat to coral reefs, especially those at shallower depths, such as those damaged in recent years in the South Pacific by what is known as bleaching. As part of that process, coral loses its color and its skeleton is exposed.
“That could destroy or really affect the coral reef,” he said.
Reaching the coral reef posed a particular challenge for scientists and photographers because of its depth, those involved in the project said. They had to use special breathing equipment and a mixture of gases that contained helium, they said.
John Jackson, a 1 Ocean film director involved in the project, likened the reef’s shape to lace. In an interview on Thursday, he said there was still a lot of work to be done when it came to underwater exploration, pointing out that only about 20 percent of the world’s seabeds had been mapped.
“We know every detail of Mars, every detail of the Moon and certain planets,” said Mr. Jackson.
Richard Norris, a professor of paleobiology at the Scripps Institution of Oceanography at the University of California, San Diego, who was not involved in the project, said Thursday the discovery was gratifying.
“Tahiti is beautiful because it is far from sediment sources on land where the water can become cloudy and it becomes more difficult for the algae to grow in these deepwater reefs,” said Professor Norris.
He compared the relationship between coral and algae to that of the human body and yeast, and said it was critical to maintain a delicate balance.
“If they are stressed by, for example, unusually warm temperatures, a symbiotic relationship with the algae turns into an antagonistic relationship, with the algae damaging the coral and the coral losing them,” said Professor Norris.
Once the reef and the marine species that call it home are better understood, those involved in the project said they would try to take conservation measures to protect the ecosystem.
“Without research,” Mr. Rosenfeld said, “you can’t have science.”