Chinese sub discovers the world’s largest whale graveyard

A startling discovery from the depths of the Indian Ocean has uncovered what scientists say is the world’s largest whale graveyard, where a sweeping field of both recent and ancient carcasses is nourishing dense communities of deep-sea life.

The site is also believed to be the deepest and oldest whale graveyard ever identified, according to research published in Nature, with some fossils traced to 5.3 million years ago.

Peering out from a cramped submersible, the Chinese team encountered a cast of unusual creatures — many thought to be previously unknown to science — feeding on and around the remains.

Among the nearly 500 skeletons recorded along a 1,200km corridor west of Australia, at depths reaching 7,000 metres, researchers also identified a new — though extinct — species of whale.

Scientists already knew that when whales die and sink to the seabed, their bodies — known as “whale falls” — become a vital food source for creatures living on the ocean floor.

“But discovering a necropolis of this scale was completely unexpected. The size of distribution, the depth and the age range were far beyond anything we had imagined,” the scientist said.

The team proposed several possible reasons so many whales may have ended up in this corridor, including its importance as a feeding ground and the presence of a V-shaped trench that may channel carcasses down to the seafloor.

‘Vibrant ecosystems’

The discovery came after 32 dives by the Fendouzhe submersible in 2023, though the findings were only disclosed yesterday.

The vessel carried as many as three people on each descent and used robotic arms to collect fossil samples.

Co-author Peng Zhou said seeing the whale graveyard firsthand “was a truly incredible experience”.

“The vibrant ecosystems we saw offered a completely different perspective on this otherwise dark and cold ocean floor,” the researcher said.

Among the animals found living off the carcasses were jellyfish, worms, snails, crustaceans, brittle stars and molluscs — bivalves among them.

Based on the number of bones recovered — most from beaked whales — the scientists estimated the wider Diamantina Zone may hold more than 10 million carcasses.

Xiaotong Peng said the soft tissue and lipids contained in that many carcasses “translates to roughly 6.7 million tonnes of sequestered carbon”.

That represents a vast store of nourishment for deep-sea animals, much as hydrothermal vents support their own thriving ecosystems on the ocean floor.

Some species observed by the researchers are also known from hydrothermal vents and cold seeps, raising the possibility that whale carcasses help link these isolated deep-sea communities.

Although this is by far the largest whale graveyard yet documented, the study said fossils recovered during trawling suggest others may exist off South Africa, the Iberian peninsula and the Crozet islands.

‘Truly unique discovery’

Craig Smith, a University of Hawaii oceanographer who discovered the first whale fall in 1987 and was not involved in the new research, told AFP the findings were “extremely exciting”.

“The vast number of fossil whale falls documented, including a new species of beaked whale, is truly amazing and is of major importance to understanding whale evolution and whale distributions over geologic time,” he said.

Amy Baco-Taylor, a whale fall researcher at Florida State University, told AFP the “remarkable discovery” would “likely provide many new insights”.

“It does seem very strange” that so many whales died in this area, Ms Baco-Taylor admitted, adding that “we don’t know enough about whale consciousness”.

US palaeontologist Stephen Godfrey likened the “truly unique discovery” to landmark moments in underwater science, including the first identification in 1977 of hydrothermal vents crowded with life on the seabed.

He urged future submersible expeditions to search for more whale graveyards in oceans around the world.

The discovery, Mr Godfrey wrote in a linked Nature paper, “reminded me of a trailer for the first in a series of epic movies”.

“I hope that there will be many more of these blockbusters to come,” he added.