Written by Caitlin DevorThere’s life under ice. Scientists found an entire community of bacteria living 800 metres under the surface of glaciers in Antarctica. These bacteria rely on each other to survive in the dark, isolated, subzero lake.
At the south-eastern edge of the Ross Ice Shelf, under the ice of glaciers, lies the liquid water of Lake Whillans. The thick layer of ice keeps the freshwater lake isolated from the world above, stopping nutrients from flowing down into it. How could anything survive there?
Recently, almost 4000 species of bacteria were found in Lake Whillans. The bacteria seem to survive by getting nutrients from the bedrock. The weight of the ice crushes the rocks, and the minerals in the rocks react with oxygen in the water. This reaction makes the rocks a source of energy for the bacteria.
The bacteria living in Lake Whillans also carefully recycle all the nutrients they can. The ecosystem of bacteria relies on rescuing nitrogen, another important nutrient, from dead bacterial cells.
When studying Lake Whillans, scientists had to be careful not to contaminate the lake with bacteria from above ground. If samples from the lake were contaminated, the researchers wouldn’t know if bacteria actually came from the lake, or if they were just carried on the equipment.
Introducing new bacteria into Lake Whillans could also be dangerous for the bacteria living beneath the ice. After being isolated for so long, the ecosystem could be disrupted by visitors. To break into the lake, researchers melted a hole in the ice using hot water. The hot water was kept super clean by filtering it, blasting it with ultraviolet radiation, heating it, and disinfecting it with hydrogen peroxide.
The ecosystem of bacteria in Lake Whillans shows how life can survive in harsh conditions. Perhaps single-celled life could also live beneath sheets of ice on Mars, feasting on the rocks.
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