That life can thrive under such extreme conditions – in the dark and at very low temperatures – is a complete surprise.

The lion’s share of the Antarctic coast is surrounded by ice shelves or ice shelves: large floating expanses of ice fed by glaciers and attached to land. Together they cover nearly 1.6 million square kilometers of water and the underlying seabed. The underlying water is not very inviting due to the presence of those ice shelves; it is pitch dark and extremely cold. And yet there is life in those waters. In fact; there is a thriving ecosystem with a wide range of species. Researchers write that in the magazine Current Biology.

Ekstrom

They are based on research under the Ekström Ice Shelf. This ice shelf covers an area of ​​about 8,700 square kilometers and is up to 200 meters thick in places.

To drill

To better understand what lives beneath the ice shelf, researchers used warm water to drill two holes in the ice shelf. They then collected and identified life forms that lived in the waters and seafloor beneath that ice. And against all expectations, this resulted in much more work than expected. For the waters turned out to be home to a wide variety of species. “The discovery of so much life under these extreme conditions is a complete surprise and a reminder of how unique and special Antarctic marine life is,” said researcher David Barnes.

In total, the researchers encountered no fewer than 77 different species, including bryozoans and tube worms. “It’s great that we’ve found evidence for so many different types of animals,” said Barnes. But it also raises questions. “Most feed on micro-algae (phytoplankton), but plants or algae cannot live in this environment. So the big question is, how can these animals survive and thrive here?” For now, algae living further up in open water are believed to be fed under the ice shelf. And apparently on such a large scale that the animals that live under the ice shelf can not only survive, but actually prosper; for example, at least four of the species discovered under the ice shelf were found to grow just as fast on an annual basis as comparable organisms that lived in open water.

Almost 6000 years

But it wasn’t just the wide array of life forms that amazed researchers. The extreme habitat turned out to have another surprise in store. For example, a radiocarbon dating of dead fragments of animals resting on the seafloor indicated that some of those animals had died very recently and others as much as 5800 years ago. “So even though we’re three to nine kilometers from the nearest open water here, an oasis of life may have existed here under the ice shelf for nearly 6,000 years in a row,” said researcher Gerhard Kuhn.

Previous research

This is not the first time that researchers have taken a look under an ice shelf. Previously, holes were also drilled in ice shelves in order to then use cameras to see what can be found underneath. What makes this study special is that the animals that live under the ice shelf have actually been collected and identified. In addition, the wide range of species is also unique; more species have been found under the Ekström Ice Shelf than were known to us until recently under all the ice shelves combined.

For now, the study is at least calling into question an important assumption about life under ice shelves. For example, researchers thought that the number of life forms and species gradually decreases the further you are away from open water (and therefore also sunlight). It was expected that filter feeders would be the first to drop out, but that turned out not to be the case. Life at a considerable distance from open water is also much more diverse than expected.

More research into what lies beneath the ice shelves – which can also be found around Greenland, for example – is urgently needed. This is the only way to get a better picture of what lives there now and what has lived in the past. However, the research into this is a race against time, the researchers emphasize. Climate change is causing the ice shelves to thin and several plateaus have already lost significant chunks of ice and some have even collapsed completely. And that obviously also has consequences for the ecosystem below, which has been able to survive for thousands of years in darkness, cold and with limited resources. “The least disturbed habitat on Earth could be the first habitat to disappear as climate change causes the ice shelves to disappear.”