Corals are the guards of the coast, and heart of the ocean. Without corals, the ocean is lifeless, it has no beauty and calmness. On the other hand, for people living around the coast, corals are their bread and butter as they feed the sea food which people depend on.
Sri Lanka also has a long line of coral reefs though most of them are in danger because of human activity. However, a group of French researchers recently amazed the world by discovering one of the world’s largest pristine coral reefs off the coast of Tahiti, an island in the Pacific Ocean that is part of French Polynesia. Though it was disclosed last week, they found it in December.
Rose-shaped giant
The length of the coral reef is estimated to be almost two miles long and 200 feet wide. The corals are rose-shaped and some of them are giants, measuring up to more than 6.5 feet across. Generally, coral reefs are developed in warmer waters at depths of up to 25 metres, because they need sunlight to grow. But Tahiti reef lies in the ‘twilight zone’ 30 to 120 metres below the sea surface where there is still enough light for corals to grow and reproduce. The reason for its rose-shape is that they need to cover more area to absorb the little sunlight that filtered into the deep sea, according to the scientists.
Who discovered it ?
The coral reef was first discovered by a recreational diving club. Then, an exploration team of France dived to explore the reef. The team was headed by the photojournalist Alexis Rosenfeld and France’s CNRS-CRIOBE, an organization linked to the French National Center for Scientific Research (FNCSR). Cinematographer John Jackson and Dr Laetitia Hédouin, a researcher at FNCSR, were also among the explorers who dived to see the reef along with local diving club months earlier.
Alexis Rosenfeld, the leader of the team of international divers, said the reef, which stretched “as far as the eye can see,” was “magical to witness.”
“It was like a work of art,” he said.
“In times when we talk a lot about sad, anxiety-provoking and catastrophic topics, it’s fascinating to realize that there are extraordinary things that exist and that can still be discovered,” he further said.
“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 Dr Hédouin, a marine biologist with the FNCSR and the environmental research center CRIOBE. What struck Dr Hédouin was that the corals looked healthy and weren’t affected by a bleaching event in 2019.
UNESCO support
The whole project was supported by UNESCO, the UN Educational, Scientific and Cultural Organization. In fact, the exploration is part of One Ocean project by UNESCO to map the whole world’s seabed. Their aim is to complete the project by 2030 and study the unexplored parts of the seabed. For the moment, it is only 20% seabed that has been mapped.
“To date, we know the surface of the moon better than the deep ocean,” UNESCO Director General Audrey Azoulay said sarcastically about that in a release.
“The discovery suggests that there are, in fact, many more large reefs out in our ocean at depths of more than 30 meters, which have not been mapped,” UNESCO marine policy official Julian Barbiere said. “It’s quite a puzzling finding.”
Barbière was also of the view that one of the key questions going forward will be to understand not only how the Tahiti reef is “in such good condition” but also “how such coral reefs can grow in this twilight zone of the ocean.”
“While we are witnessing major investment in space exploration, there’s not enough on studying our own home and the ocean in particular,” he said. “And I think this is really where we want to put our emphasis in the next 10 years - to create the knowledge we need to put the planet on the sustainable path through marine protected areas.”
According to France’s National Oceanic and Atmospheric Administration oceanographer Mark Eakin, the reef wasn’t uncovered until now, because it is in a spot where many researchers haven’t spent a lot of time in.
As UNESCO marine policy official Julian Barbière said, the extraordinary thing about the coral reef is that it was not affected by the recent volcanic eruption in Tonga that triggered tsunami waves across the Pacific. Dr Hédouin 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. So, more dives are planned in the coming months.
Wonder of technology
Anyway, the Tahiti exploration project was successful thanks to scientific development, because divers need high tech apparatus to stay for longer periods of time at the deep sea. So in this effort the divers were helped by scuba rebreathers, which filter carbon dioxide out of exhaled air and recycle much of the unused oxygen. Thus the dive team was able to spend about 200 hours studying the reef. The rebreathers contain a special helium-based gas mixture that guards against narcosis or a state of drowsiness.
The threat
We know that coral reefs are the main component which protects the coastline from sea erosion. But the most important thing about coral reefs is that it is crucial to Earth’s biodiversity. They are an important food source, as well as habitat, for a wide array of marine organisms. Yet the problem is how these ecosystems could sustain with increasing human-caused climate changing threats.
Roughly 4,000 miles west of Tahiti, off the coast of Australia, the Great Barrier Reef - the largest reef system in the world - has suffered several large-scale coral bleaching events over the past two decades due to extreme ocean warming. As CNN article on the Tahiti coral reef by Rachel Ramirez puts, a 2021 study found 98% of the reef had been impacted by bleaching since 1998. And despite having adapted to higher heat thresholds, the study found the corals now have less time to recover between more frequent bleaching events.
Meanwhile, Steven Mana’oakamai Johnson, a postdoctoral research scholar and marine scientist at Arizona State University, has said to CNN that though the Tahiti reef appears healthy right now, there’s still concern that the effects of climate change will reach it.
“Just because the reef currently doesn’t show any impacts from climate change, it doesn’t mean that’s going to hold into the future,” Johnson told CNN. “And so we can’t just assume that because no one knew it was there, and when we found it, it was in good shape that it will continue to dodge the proverbial climate bullets.”
Johnson’s recent research found that 60% to 87% of the world’s oceans are expected to experience devastating biological and chemical changes, including higher levels of acidity and shifts in oxygen levels by 2060, which would drastically harm the planet’s vast coral reefs. And in a special report on oceans in 2019, the UN Intergovernmental Panel on Climate Change concluded with high confidence that the impact on marine ecosystems will worsen if fossil fuel emissions continue at-pace.
Even if global warming is limited to 1.5 degrees Celsius - the ideal goal of the Paris Agreement - “coral reefs are projected to suffer significant losses of area and local extinctions,” CNN quoted scientists’ report, noting that efforts to restore them will likely be futile at that point, given the enormous stress they are already under.
“The big takeaway is that (the UNESCO team) found this track of reef that’s in good condition, which definitely speaks to how little we’ve done to truly map the ocean,” said Johnson to CNN, who is not involved with the research. “This emphasizes the importance of passing meaningful climate policy including finding ways to support the traditional stewards of these oceanscapes.”
So, though we are fascinated by the new discovery in Tahiti, there is a lot more to be done.