When a whale dies its rotting remains sink to the deep sea floor, where it becomes a habitat for all sorts of creatures. Finding one of these natural whale-falls would be like finding a needle in a haystack, in fact only 6 have ever been spotted.
Whale backbone on the sea floor © NERC ChEsSo Consortium
However a team of scientists have not only found the first natural whale-fall in Antarctica, but have identified 9 new species of creatures living there, giving more clues about the biodiversity of the deep, dark sea.
Marine biologist Diva Amon of the Natural History Museum and University of Southampton and her team publish their findings today.
Scientists mainly study whale-falls by deliberately sinking a carcass to the sea floor. It soon attracts scavengers that strip it of its flesh and then other colonies of animals move in to use up the remaining nutrients.
New species of amphipod © NERC ChEsSo Consortium
This Antarctic whale-fall was discovered by chance when the team was at the end of an investigation into deep-sea vents in the oceans of the area.
They were using an underwater remotely-operated vehicle (ROV) called ISIS. 'We were preparing for the ROV to begin ascent back to the sea surface when we noticed some white blocks in the distance,' said Amon. This was the backbone of a whale on the seabed, almost 1.4km (a mile) deep in an undersea crater.
The team sent the ROV, with its high-definition camera, back to investigate. And they collected samples of the bones and the creatures living there.
Osedax bone-eating worm © NERC ChEsSo Consortium
'This is the first whale-fall to have been found in the Antarctic, which is ironic considering the large numbers of cetaceans present in the area, but understandable considering how poorly explored the deep sea is around the Antarctic,' adds Amon.
DNA tests revealed the bones belonged to a southern minke whale. And the team identified 4 new species of worms, including one of the bone-eating worms from the Osedax genus, 2 new species of crustaceans, and 3 new species of gastropod.
'There was a wealth of new life living on the skeleton,' says Amon. 'It is still surprising to me that in this day and age, new species are still being found on our planet!
New species of polychaete worm © NERC ChEsSo Consortium
'The skeleton was very badly eroded implying that it had been on the sea floor for possibly decades and yet there were so many animals still using it for food and shelter.'
The team say this find highlights how the planet’s largest animals are also part of the ecology of the very deep ocean.
They provide food and shelter long after their deaths, helping us to understand more about how organic matter is recycled in the oceans.
Studying this whale-fall is also helping scientists learn how species evolve and disperse across the vast distances of the deep ocean.
The research involved the University of Southampton, Natural History Museum, British Antarctic Survey, National Oceanography Centre and Oxford University, is published today in Deep-Sea Research II: Topical Studies in Oceanography.