A huge whale graveyard discovered in the southeast Indian Ocean is the deepest, most extensive and oldest known. The necropolis, which could contain up to 10 million corpses, It includes both modern and ancient remains, with fossils that are 5.3 million years old.
The discovery was made by a team led by the Chinese Academy of Sciences and made up of Italian and New Zealand researchers, which publishes the details in Nature.
The cemetery, which extends for about 1,200 kilometers of the seabed, is in the Diamantina fracture zone, in the Indian Ocean and the remains are found up to 7,001 meters deep (in the other known cemeteries they do not exceed 4,200).
But it’s not just a dead place. The study explains that “one of the most fascinating phenomena” of the deep sea is the ‘whale fall’, which occurs when one dies and its corpse sinks to the bottom of the ocean.
There, their remains create “an oasis” of biodiversity that houses specialized communities composed of bone-eating worms, chemosynthetic bivalves and ophiuras (similar to starfish). In the case of the new cemetery, some are unknown to science.
These “exceptional characteristics” of the place offer “a privileged perspective on the evolutionary history of beaked whales, “some enigmatic deep-sea predatory cetaceans,” researcher at the University of Pisa (Italy) Alberto Collareta, one of the signatories of the article, told EFE.
Furthermore, it reveals a fossilization process still little studied, such as the conservation of vertebrate remains directly in the depths thanks to the protective action of thick incrustations of iron and manganese.
Paleontological heritage
This discovery, made in 2023 and which was “largely unexpected” – Collareta acknowledged – was achieved with a Fendouzhe bathyscaphe, which submerged in 32 areas of the Diamantina trench and recovered 43 fossils.
485 fossil sites and five ‘whale falls’ have been located still active (hosting animal communities). Researchers estimate that the area could have more than 10 million corpses, which also represents a large carbon sink.
In almost all explorations the presence of fossils has been documented, often by dozens in each dive, so the researcher considers that the remains directly observed represent “only a minimal part of the immense paleontological heritage that is preserved on the seabed.”
A huge and ancient place, whereThe oldest remains recovered and dated are from 5.3 million years agoin it Pliocene early, specifically, part of a skull of the extinct species Pterocetus benguelae.
Among the identified fossils there are current species, such as the deep-sea beaked whale or the strap-toothed whale, and extinct species such as the Pterocetus diamantinae, until now unknown and which has been described thanks to this research.
This site gives a “privileged perspective” on the beaked whales that, despite their size (up to 12 meters) and the variety of species (at least 24 living), “Its biology is largely unknown, “Well, some have never been sighted at sea and are only known from rare strandings.”
It is not only a necropolis, but also “a fundamental archive to understand how these deep-sea hunters developed such an extreme lifestyle over millions of years.”
Biodiversity oasis
A place that houses a lot of life, because the corpses deposited in the bottom can sustain extremely specialized biological communities for a hundred years, known as ‘whale fall communities’.
Some “extraordinary” ecosystems where there are organisms that feed on the remains – even taking advantage of the collagen and lipids inside the bones – and others that use the skeleton as an anchor point in the background, he explains.
For now, Five active deposits have been detectedamong them one formed by three vertebrae of beaked whale at 6,789 meterswhich is the deepest known and houses organisms that “seem totally new to science.”
Among the bone remains, ophiuras, bone-boring worms (Osedax) and chemosymbiotic bivalves have found refuge. In addition, the presence of the sea daisy associated with wood was recorded for the first time.
