Life - and potentially new species - discovered below 900m Antarctic ice shelf by Cambridge researchers
The extraordinary discovery of life, below 900 metres of Antarctic ice, was described as a “fortunate accident” by Cambridge researchers, who believe they may have uncovered species previously unknown to science.
Some 260km from the open ocean, the team was drilling in the Filchner-Ronne Ice Shelf, on the South Eastern Weddell Sea, for an exploratory survey when they stunned to find the existence of stationary sponge-like animals and unidentified species attached to a boulder on the sea floor.
They exist in complete darkness, and at temperatures of -2.2°C - conditions very few animals have ever been observed to live under before.
Biogeographer Dr Huw Griffiths, of the Madingley-based British Antarctic Survey, said: “This discovery is one of those fortunate accidents that pushes ideas in a different direction and shows us that Antarctic marine life is incredibly special and amazingly adapted to a frozen world.
“Our discovery raises so many more questions than it answers, such as how did they get there? What are they eating? How long have they been there? How common are these boulders covered in life? Are these the same species as we see outside the ice shelf or are they new species? And what would happen to these communities if the ice shelf collapsed?”
Floating ice shelves cover more than 1.5 million square kilometres of the Antarctic continental shelf, but the British Antarctic Survey says only a total area of around the size of a tennis court has been studied, through eight prior boreholes.
It means this is the greatest unexplored habitat in the Southern Ocean, but theories on what might survive under such ice shelves assume all life becomes less abundant the further you go from open water and sunlight.
There have been discoveries of some small mobile scavengers and predators, including fish, worms, jellyfish and krill, in these habitats, but filter-feeding organisms that depend on a supply of food from above were expected to be amongst the first to disappear further under the ice.
But geologists drilling through the ice to collect sediment samples were in for a number of surprises.
First, they hit a rock instead of the expected mud at the bottom of the ocean.
Then the borehole camera footage showed them a large boulder covered in strange creatures.
The British Antarctic Survey says this is the first record of a hard substrate, or boulder, community deep beneath an ice shelf and appears to rewrite the theories of what could survive there.
The researchers have calculated using water currents in the region that this community may be as far as 1,500km upstream from the closest source of photosynthesis.
Glacial melts or chemicals from methane seeps have been known to provide nutrients for other organisms, but understanding what is sustaining this community is not yet known.
And nor will it be until the researchers overcome the substantial challenge of collecting samples of these organisms.
Dr Griffiths said: “To answer our questions we will have to find a way of getting up close with these animals and their environment - and that’s under 900m of ice, 260km away from the ships where our labs are.
“This means that as polar scientists we are going to have to find new and innovative ways to study them and answer all the new questions we have.”
Time is not on our side, of course, or theirs. With climate change bringing about the collapse of these ice shelves, the opportunity to study and protect these ecosystems is limited.
The study, published on Monday in the journal Frontiers in Marine Science, is titled Breaking All the Rules: The First Recorded Hard Substrate Sessile Benthic Community Far Beneath an Antarctic Ice Shelf.
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