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Friday, March 15, 2013

Life in subglacial Antarctic lakes


Did you know there are hundreds of lakes underneath the Antarctic ice sheet? These bodies of water, which were detected by ground penetrating radar, are about 800 meters under the ice and are totally isolated from the outside world. This means that anything living in those lakes has had no contact with the outside world since the lakes’ formation. This is a treat that’s too good to pass up for either biologists or astrobiologists. So far it looks like they won’t be disappointed.

Scientists have discovered that under the massive Antarctic ice sheets there lies a vast hydrological system of liquid water.  This water exists because geothermal heat flow from below, coupled with pressure, movement, and the insulating nature of the ice sheet above, is great enough to maintain some areas at the base of the ice sheet above the freezing point, even in the extreme cold of Antarctica.  In topographic depressions there are hundreds of lakes, both large and small; some are isolated, but many are interconnected by water channels and large areas of saturated sediments, the water eventually running out into the Southern Ocean as the ice sheet becomes a floating ice shelf.
WISSARD Project.

Of course, we first have to find out what’s down there. To that end, NASA is funding the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project. The goal of this project is to drill a hole through the ice and see what’s in the lake beneath it. This is vastly more complicated than it sounds for several reasons. To begin with, the team had to drill a hole all the way to Lake Whillans, half a mile down through the ice. Next, the instruments had to be threaded down that long hole and then brought back up with samples and without scraping along the sides and becoming damaged. Also, the instruments had to be completely sterile so as not to contaminate any findings. And lastly, did I mention this was Antarctica? This is not the most hospitable place in which to stand around doing fieldwork.

Alberto Behar, co-investigator of the WISSARD project, gives us a tour:




Although the findings are preliminary, there do appear to be microbes in the subglacial lake water. This is good news for people hoping to find life under the ice sheets of other worlds, such as Europa or Enceladus. The next step is to see how closely these samples resemble other forms of life on Earth.

You can hear interviews with Helen Fricker (discoverer of Lake Whillans), microbiologist Jill Mikucki and planetary scientist Chris McKay on this Feb. 11, 2013 Big Picture Science podcast