The variety of species found below an Antarctic ice shelf shows that life can survive in hostile, food-poor environments for thousands of years
20 December 2021
An astonishing variety of marine life has been discovered in the freezing darkness hundreds of metres below Antarctica’s ice shelves, including corals, clams, sea mosses, snails and worms.
In 2018, a German research team drilled holes in the Ekström Ice Shelf using hot water and collected samples from two sites in the water beneath. An analysis of the samples they collected suggests the environment is home to 77 species – a greater number than found during all previous studies below Antarctica’s ice put together.
“It’s a tantalising view of one of our least-known habitats,” says David Barnes at the British Antartic Survey, who studied the organisms under the microscope. “These two samples are very rich. The thing that really leaps out is just how rich the bryozoans – the sea moss animals – are.”
Radiocarbon dating shows some of the bryozoans are several thousand years old. Most of the species found are immobile, so their discovery in such a hostile and low-food environment suggests they are surviving on phytoplankton carried by poorly understood currents beneath the ice shelves.
They appear to be growing just as fast as the same species found growing on open-water continental shelves, to Barnes’ surprise. He says it shows how long life can persist with very little food and by conserving energy.
The research follows another study earlier this year that found a surprising array of sponges on a boulder deep beneath Antarctica’s ice. The variety of life found this time suggests that environments below the ice are more habitable than previously thought, says Barnes. “Perhaps life is capable of surviving much more ice cover than we thought was the case,” he adds.
However, Barnes and colleagues note that this undisturbed and biodiverse habitat beneath the ice “could be the first habitat to go extinct” as Antarctica’s ice shelves collapse due to climate change.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2021.11.015.
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