Deep below the ice shelves of Antarctica, an abundance of new and unexpected lifeforms has been discovered. They may not be big and they may not be pretty, but the surprising discovery is teaching scientists how life can persist in one of the most obscure environments on Earth.
As reported in the journal Current Biology, researchers from the British Antarctic Survey have recently announced the discovery of 77 new species beneath the Antarctic ice shelves, including sword-shaped bryozoans and serpulid worms.
Bryozoa, commonly known as moss animals, are a phylum of simple invertebrate animals that live in aquatic environments. Typically no larger than a millimeter, these animals often consist of tough exoskeletons, similar to those of corals, with a bunch of hair-like tentacles used to filter feed. Serpulid worms are similar, sedentary suspension feeders.
Fragments of Bryozoans were discovered on the seabed. Image credit: David Barnes
Even the presence of these simple creatures raises some big questions. Most ecosystems start with sunlight, which is absorbed and converted into usable forms of energy via photosynthesis. However, the animals live beneath hundreds of meters of ice where no light can penetrate. So, how on Earth do they sustain themselves?
“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,” Dr David Barnes, lead study author and marine biologist at British Antarctic Survey, said in a statement.
“So the big question is how do these animals survive and flourish here?”
The team suspects the answer lies in significant amounts of algae that have been carried under the ice shelf from open water, although questions still remain. Curiously, life is more abundant beneath the ice shelf than the open waters.
This little-known environment was accessed using a 200-meter (656-foot) deep hole that was drilled back in 2018 on the Ekström Ice Shelf near Neumayer Station III in the South Eastern Weddell Sea. Conditions on the surface here are incredibly harsh, with temperatures often dipping below zero degrees centigrade. While lifeforms have been discovered beneath the ice shelves of Antarctica before, ranging from krill to even fish, this new research has raised plenty of surprises.
“Another surprise was to find out how long life has existed here,” explained Dr Gerhard Kuhn, study co-author from the Alfred Wegener Institute who coordinated the drilling project, Carbon dating of dead fragments of these seafloor animals varied from current to 5800 years. So, despite living 3-9 km from the nearest open water, an oasis of life may have existed continuously for nearly 6000 years under the ice shelf. Only samples from the sea floor beneath the floating ice shelf will tell us stories from its past history.”
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