A new discovery here on Earth may have implications for the search for life elsewhere, in particular icy waterworlds like Jupiter’s moon Europa.
Lake Vida in Antarctica is not the kind of place you might think would be teeming with life – a very cold lake frozen over by a sheet of ice up to 27 metres (88 feet) thick. With no sunlight and salt content six times higher than seawater, it would seem quite inhospitable, perhaps even to the hardiest known life forms.
But as we’ve learned before, things are not always as they seem. Lake Vida is not only habitable, it is indeed inhabited by an amazing variety of microorganisms, according to new research just published yesterday in Proceedings of the National Academy of Sciences.
The microbes were discovered after scientists drilled through the ice into the water below, in 2005 and 2010.
The abundance of microbes is less than in freshwater lakes in temperate zones, about one-tenth the amount, but the fact they are even there is a fascinating testament to just how adaptable and resilient life can be.
As Peter Doran, a scientist from the University of Illinois at Chicago and team member, says, “Lake Vida is not a nice place to make a living in. It is quite remarkable that something wants to live in that cold, dark and salty environment at all.”
Some of the microbes are about the same “normal” size as other microbes, 1 micrometre in diameter or so, but most of them are much smaller, only about 0.2 micrometres.
Even more interesting is how this discovery may relate to similar environments elsewhere in the solar system, such as Europa, as well as Saturn’s moons Enceladus and Titan.
All of these moons are now thought to have oceans and / or lakes beneath their ice-covered and frozen surfaces. These alien waters would also be deep, dark and cold; could life exist there too? On Earth, such extreme life forms can use dissolved organic carbon or molecular hydrogen for energy, without the need for sunlight.
In the coming months, US, British and Russian scientists are planning to drill into other subsurface Antarctic lakes – Ellsworth, Whillans and Vostok – which are subglacial lakes covered by thicker ice for millions of years. What might be found there?
The more we learn about these extreme habitats on our own planet, the better idea we will have of what may be out there, as well.
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