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Updated January 18, 2019: Scientists analyzing the lake samples have now found signs of ancient life, Nature reports. Carcasses of crustaceans and a tardigrade no bigger than a poppy seed have been discovered, to the surprise of the team. Curiously, at least some of these tiny creatures would have been land dwellers. That includes the tardigrade, which looks a lot like a species found in damp soils, and the tendrils of a plant or fungus. How they got there is a mystery but scientists suspect they lived in the ponds and streams in the Transantarctic Mountains during a brief period of warmer weather (circa 10,000 years ago or circa 120,000 years ago). These mountains are approximately 50 kilometers from Lake Mercer so how exactly they ended up there is a big question we have yet to find the answer for. Next steps involve sequencing the animals' DNA and carbon dating the material to determine its age.
Antarctica might look like a vast, inhospitable wasteland of ice and snow, and for the most part, it is. Even the penguins that call the continent their home stick the coastal peripheries. But there are at least some areas in Antarctica that are teeming with life.
In waters far below the West Antarctic ice sheet there is a subglacial lake called Lake Mercer accommodating colonies of bacteria – a fact that could have huge significance for the search for extra-terrestrial life, and life on Mars in particular. Only last year, astronomers discovered Mars was hiding a giant lake full of subterranean water, which may potentially – like Lake Mercer – be alive with microbial beings.
The discovery of these Antarctic-dwelling microbes is the result of a project that saw a team of polar scientists drill a 1,000-meter-deep (3,280-foot) borehole towards Lake Mercer in December, in order to determine the diversity of life there. The lake itself is more than twice the size of Manhattan.
Early testing suggests that there are as many as 10,000 bacterial cells per milliliter of water. And while that is just a hundredth of the number usually found in the open ocean, it goes to show Antarctica is far from barren. It is far too early to say for sure but it may even suggest the potential for higher life-forms (tardigrades, for example, not aliens) to exist.
“We saw lots of bacteria – and the [lake] system has enough organic matter, you would think, to support higher life-forms,” John Priscu, expedition leader and a professor of ecology at the University of Montana, told Live Science. Adding, the search for these higher life-forms won’t happen for another couple of months.
But Lake Mercer is not the only subglacial lake beneath the West Antarctic Ice Sheet to be found brimming with bacterial lifeforms. In 2013, polar scientists drilled 800 meters (2,600 feet) to Lake Whillans, where they found bacteria that feed on methane. Not only does this this go to show that life (even if only on a microbial level) is able to survive such hostile environments – raising the possibility of life in areas of the Solar System like Saturn and Jupiter’s icy moons – it may even help us find a way to manage greenhouse gas emissions, protecting life here on Earth.
The exploration of these great subglacial lakes has apparently only just begun. Priscu said he believes the entire continent of Antarctica is one giant eco-system of wetland, comprising of hundreds of these buried lakes each connected to one another via a network of rivers – a little like a canal system.
For now, though, we’ll have to wait and see.
[H/T: Live Science]
