New research suggests that the lakes underneath Antarctica’s thick ice could be home to more microbial life than the scientific community has previously recognized. Expeditions led to investigate two subglacial lakes that have been largely isolated for millions of years could answer questions about evolution on Earth as well as life on other planetary bodies, like Jupiter and Saturn’s icy moons and Mars’s southern ice cap. The findings are reported in the journal Science Advances.
"Our eyes now turn to predicting the physical conditions in liquid water reservoirs on icy moons and planets. The physics of subglacial water pockets is similar on Earth and icy moons, but the geophysical setting is quite different, which means that we're working on new models and theories. With new missions targeting icy moons and increasing computing capabilities, it's a great time for astrobiology and the search for life beyond the Earth," says co-author Professor Martin Siegert, Co-Director of the Grantham Institute - Climate Change and Environment at Imperial.
While prior expeditions have discovered over 400 subglacial lakes underneath Antarctica, their environments are still largely an enigma. Many of the lakes have been, shall we say, “quarantined” from each other and the atmosphere for millions of years due to the topography of the ice sheet. This has provided the unique conditions for evolution to take place in relative isolation.
Professor Siegert, along with his colleagues at Imperial College London, the University of Lyon, and the British Antarctic Survey, was curious to learn about how microbes could evolve to survive persistent extreme cold conditions without access to sunlight.
Now the team has detected that geothermal heat from Earth’s interior generates convection currents within the subglacial lakes, resulting in the movement of sedimentary particles and oxygen throughout the water. This, they say, could explain why more of the lakes seem to be able to support life.
Lead researcher Dr. Louis Couston comments: "The water in lakes isolated under the Antarctic ice sheet for millions of years is not still and motionless; the flow of water is actually quite dynamic, enough to cause fine sediment to be suspended in the water. With dynamic flow of water, the entire body of water may be habitable, even if more life remains focused on the floors. This changes our appreciation of how these habitats work, and how in future we might plan to sample them when their exploration takes place."