Scientists discover 149 new marine species off Christmas and Cocos (Keeling) Islands
Chunky sea stars, such as Atheraster umbo, were among the 149 species uncovered near the Indian Ocean territories. (Supplied: CSIRO)
In short:
Researchers say they have catalogued at least 149 new species from waters around Christmas and Cocos (Keeling) Islands.
The animals have been catalogued over the past five years following voyages in 2021 and 2022.
What's next?
The data will help inform the management of Australia's most remote marine parks.
More than 100 new species have been recorded and catalogued for the first time in some of Australia's most remote territorial waters.
The often bizarre benthic creatures were found dwelling across 22 seamounts, or massive subsea mountains, near the Christmas and Cocos (Keeling) Islands, nearly 3,000 kilometres north-west of Perth.
Scientists from Museums Victoria, CSIRO and Australian Museum collected 1,000 specimens over two voyages in 2021 and 2022 aboard their 94-metre oceanographic research vessel, the Investigator.
A close relative of the starfish, brittle stars or ophiuroids were the most abundant creature of all those found. (Supplied: CSIRO)
Their findings, published this week, suggest at least 149 — everything from sea stars to worms to sea cucumbers — were unknown to humanity until now.
"It's an incredibly important environment, and we know nothing about it," paper co-author and jellyfish expert Claire Rowe said.
A new species of greeneye fish. (Supplied: CSIRO)
"Some of these specimens have been collected down to 5,000 metres below the surface. I can't even run 5ks.
"They're all weird and wacky, but really adapted to their environment, which is incredibly cool."
Claire Rowe sorts specimens aboard the RV Investigator. (Supplied: CSIRO)
Deep-sea 'flower'
One of the new species is among the deepest ever discovered in more than 100 voyages by the RV Investigator.
The annelid worm, which scientists have named Bathyvermilioides juliebrocka, is just millimetres long and was captured at a depth of around 4,990 metres.
Translucent worms like this one (Laetmonice murrayae) were found thousands of metres beneath the surface. (Supplied: CSIRO)
The animal itself is a rare sight, beyond the feather-like tentacle that protrudes from its hard tubular shell of calcium carbonate.
"In a way, it looks like a little flower," explained Elena Kupriyanova, a deep-sea worm researcher and voyage crew member
Dr Kupriyanova said it was "surprising" to find a firm-bodied creature so far down, where others had evolved to be gelatinous under the crushing weight of roughly 500 atmospheres.
"Somehow these animals managed to calcify and maintain their tube despite this high pressure in the abyss," she said.
Another of the new species, O'Loughlin's Sea Cucumber (Deima oloughlini), was named for respected Australian marine taxonomist Mark O'Loughlin. (Supplied: CSIRO)
Dr Kupriyanova said the seamounts' rich biodiversity helped dispel the long-held "endemism" theory that these habitats had developed in isolation.
Instead, she likened them to "stepping stones", allowing deep-sea organisms to hop from one to the next in a chain of ecosystems.
"Because we can have examples of both unique fauna and actually quite common species on different seamounts around the world," Dr Kupriyanova said.
Far friendlier in appearance was the sponge crab (Sphaerodromia brizops), known for its habit of wearing marine invertebrates like a hat. (Supplied: Museums Victoria/Benjamin Healley)
Snapshot of a world in flux
Almost half a decade later, the two expeditions of the RV Investigator continue to yield tranches of discoveries and a long string of publications, with more than 400 collected species still on the shelf, waiting to be described.
The often lengthy and laborious process requires scientists to prove their finds using genetic material and compare them against international databases.
The RV Investigator docked in deep water off the Cocos (Keeling) Islands in 2022. (Supplied: Museums Victoria/Benjamin Healley)
Parks Australia acting director Allyn White said the results offered important data for managing two of the authority's most distant and pristine marine parks.
The trips also involved mapping the sea floor using the vessel's advanced sonar system.
"What it does give us is a really great snapshot of what the deep-sea environment was like when the marine parks were created and what sort of species were there," he said.
"So that when you come back … you've got baseline information and you can understand what changes may happen over time in the marine environment."
Claire Rowe says deep-sea jellyfish come in brilliant colours. (Supplied: CSIRO)
Dr Rowe said it was especially critical for combating human impacts in the region.
"There are so many threats to our marine environment at the moment: overfishing, climate change," she said.
"The more we find now, the more we can understand how some species may adapt, how some species may not. It's all connected."