Deep beneath the Antarctic ice shelves, the environment is about as harsh as it gets.
Extremely cold, perpetually dark and with food sources almost non-existent, it is not exactly conducive to life, even if the Earth is home to some remarkably hardy and resolute creatures that exist in all corners of the world.
But rather surprisingly scientists have actually discovered 77 species living there, including evidence that this ‘oasis of life’ dates back some 6,000 years.
Among them were sabre-shaped moss animals and unusual worms, researchers in Germany found.
Using hot water, the team from the Alfred Wegener Institute (AWI) drilled two holes through nearly 656ft (200 metres) of the Ekström Ice Shelf near Neumayer Station III in the South Eastern Weddell Sea in 2018.
Discovery: Scientists recovered 77 species living beneath Antarctica’s Ekström Ice Shelf, including sabre-shaped bryozoans (pictured) such as Melicerita obliqua and serpulid worms
WHAT ARE SERPULID WORMS AND MOSS ANIMALS?
Serpulid worms such as Paralaeospira sicula are marine tubeworms with a crown of feathery tentacles that are bright red, pink and orange.
There are currently about 300 species of living serpulids, which live in a wide range of ocean habitats all over the world.
They build calcareous tubes and use fanlike structures to gather food particles out of the water.
Sabre-shaped bryozoans, however, are common on Antarctic shelves.
They grow in colonies that can live for up to 45 years.
Melicerita obliqua is hermaphroditic, with fertilisation and egg brooding either be internal or external.
Despite being several miles from the open sea, the biodiversity of the specimens they collected was extremely rich.
Richer, in fact, than many open water samples found on the continental shelf where there is light and food sources.
The fragments of life on the seabed collected were extraordinary and completely unexpected, the researchers said.
They discovered 77 species — including sabre-shaped bryozoans (moss animals) such as Melicerita obliqua and serpulid worms such as Paralaeospira sicula.
Lead author Dr David Barnes, a marine biologist at the British Antarctic Survey, said: ‘This discovery of so much life living in these extreme conditions is a complete surprise and reminds us how Antarctic marine life is so unique and special.
‘It’s amazing that we found evidence of so many animal types, most feed on micro-algae (phytoplankton) yet no plants or algae can live in this environment.
‘So the big question is how do these animals survive and flourish here?’
The team concluded that there must be enough algae carried under the ice shelf from open water to fuel a strong food web.
Microscopy of samples showed that, surprisingly, annual growth of four of the species was comparable with similar animals in open marine Antarctic shelf habitats.
Co-author Dr Gerhard Kuhn (AWI), who coordinated the drilling project, said: ‘Another surprise was to find out how long life has existed here.
‘Carbon dating of dead fragments of these seafloor animals varied from current to 5,800 years.
‘So, despite living 3-9km (1.8-5.5 miles) from the nearest open water, an oasis of life may have existed continuously for nearly 6,000 years under the ice shelf.
Using hot water, the Alfred Wegener Institute team drilled two holes through nearly 656ft of the Ekström Ice Shelf near Neumayer Station III in the South Eastern Weddell Sea in 2018
‘Only samples from the sea floor beneath the floating ice shelf will tell us stories from its past history.’
Despite occupying nearly 618,000 square miles (1.6 million km2), ice shelves are amongst the least known environments on Earth.
Life has been seen on camera in these dark, minus 2.2 degrees centigrade (28 Fahrenheit) cold and still habitats but rarely collected.
Current theories on what could survive under ice shelves suggest all life becomes less abundant as you move further away from open water and sunlight.
Past studies have found some small mobile scavengers and predators, such as fish, worms, jellyfish or krill, in these habitats.
But filter feeding organisms – which depend on a supply of food from above – were expected to be amongst the first to disappear further under the ice.
Researchers added that with climate change and the collapse of these ice shelves, time is running out to study and protect these ecosystems.
The study has been published in the journal Current Biology.