Largest Known Coral Colony Discovered Near Solomon Islands

The largest known coral colony in the world has been found in the southwest Pacific, near the Solomon Islands.

Visible from space, the “mega coral” — a collection of tiny coral polyps forming one organism — could be over three centuries old, reported BBC News.

The giant coral colony was discovered by a National Geographic cinematographer while visiting remote areas of the Pacific to find out how they had been impacted by climate change.

“I went diving in a place where the map said there was a shipwreck and then I saw something,” diver and cinematographer Manu San Félix said, as BBC News reported.

San Félix called to his son Inigo, who was also his diving partner, and the two ventured further below the surface to survey the coral.

San Félix described catching sight of the coral as like seeing a “cathedral underwater.”

“It’s very emotional. I felt this huge respect for something that’s stayed in one place and survived for hundreds of years,” San Felix said. “I thought, ‘Wow, this was here when Napoleon was alive.’”

The mega coral measures 112 by 105 feet, bigger than a blue whale, according to the National Geographic Society’s Pristine Seas team, reported National Geographic.

Molly Timmers, lead scientist of the expedition, said the discovery “was really serendipitous.”

“It was found the night before we were moving to another section,” Timmers said.

The colony is believed to be composed of almost one billion coral polyps, genetically identical and working in tandem like a single organism.

Though the coral colony is in “excellent health,” the researchers are concerned about global warming and overfishing — threats coral species all over the world face.

The research team hopes their discovery will lead to increased protection of Solomon Islands marine habitats.

“Finding this mega coral is like discovering the tallest tree on earth,” said founder of Pristine Seas Enric Sala via e-mail. “This discovery rekindles our sense of awe and wonder about the ocean.”

Timmers said the coral is Pavona clavus — a type of hard coral, or “shoulder blade coral” — so called due to columns that “kind of [look] like shoulders.”

The coral is primarily brown with pink, red, yellow and blue patches.

Relatives of sea anemones and jellyfish, corals are actually animals.

Since it sat surrounded by sand 42 feet below the surface, locals might have thought the coral colony was an enormous rock.

“There’s this Western belief that we have seen all of our [coastal] waters,” Timmers said in National Geographic, “but many, many people don’t have the masks and snorkels to actually put their heads in the water to see it.”

The height of a coral is typically used to estimate their age. This colony is 16 feet tall, leading researchers to believe it is roughly 300 years old, but the remarkable coral could be older than that.

“It gives you that wow factor — life really created this and has sustained this massive colony,” Timmers said. “It’s like our ancestors are still there in the water.”

The resilient organism has lived through pollution, overfishing, global heating and ocean acidification.

At a nearby reef, the team witnessed many dead corals, and they aren’t sure how resilient the recently discovered colony will be against these threats.

Corals are extremely sensitive to environmental changes. As the ocean absorbs increasing amounts of carbon dioxide, the water’s pH balance is affected, which can lead to stress for corals.

“Our climate crisis is making the ocean warmer and more acidic, and that’s eating corals worldwide, including the mega coral,” Sala said.

More acidic waters make it harder for corals to develop strong and healthy exoskeletons, which are made from calcium carbonate in the water and protect them from predators.

In 2023 and 2024, 77 percent of coral reefs around the world were subjected to temperatures high enough to cause bleaching.

“You have this life pillar that’s still there,” Timmers said. “It gives you this awe, this hope. Just seeing how big it is — the mega coral — and its survival in an area that wasn’t as healthy.”

Timmers said the location of the colony in cooler, deeper waters protected by a shelf and a slope “is really an ideal spot” that might be the reason it has stayed so healthy.

Sala said protecting 30 percent of the world’s ocean and phasing out fossil fuels is essential for the survival of corals.

“Just when we think there is nothing left to discover on planet Earth, we find a massive coral made of nearly 1bn little polyps, pulsing with life and colour,” Sala said, as The Guardian reported. “But there is cause for alarm. Despite its remote location, this coral is not safe from global warming and other human threats.”