Finding Life in the Ice

As we contemplate using long-range tools like spectroscopy to examine distant exoplanets for life, we’re also developing the hands-on equipment we’ll need for seeking it out in our own Solar System. Project SLIce (Signatures of Life in Ice) is a case in point, an attempt to study how organic material behaves in ice on other worlds by using Earth settings as an analogy. On that score, the archipelago of Svalbard has proven to be a helpful testbed.

Located in the Arctic Ocean between Norway and the North Pole, Svalbard is icy and spectacular. The image below conjures up memories of a nautical journey I took around Iceland in the 1970s, with white-capped seas pushing up against snow-clad peaks. The SLIce team sees Svalbard as a laboratory for looking for extant or extinct life, and a place to develop the protocols for working with rovers in operating environments like Mars.

Image: I love Iceland, but pushing as far north as Svalbard would really bring out the adventurer in me. Here we see rough seas in the Arctic Ocean with mountains and glaciers in the distance. Credit: NASA/AMASE/Kirsten Fristad.

Here’s Liane Benning (University of Leeds) discussing the procedures under examination:

“For SLIce, we applied the protocol we had developed to take ice cores, process them and analyze them in the field just as would happen on a rover on Mars, and then of course we took them back to the lab and did a much wider range of tests, so we really knew what we had found. There could be microbes living in the ice, but there could also be the dead bodies of microbes that used to live there, and there could be biological molecules that blew in from dust and micrometeorites. We need to identify what we’ve got, so that we know what it’s telling us.”

And if that earlier image didn’t make you think of Mars, at least the non-aqueous part of the image below should. Here’s we’re looking at the Redbeds in Bockfjorden. These are layered sediments in northern Svalbard that may be similar to layered sedimentary deposits on Mars (credit: Kjell Ove Storvick/AMASE).

An early SLIce result, described at the Goldschmidt2009 geochemistry meeting in Davos last week: The best place to look for microorganisms in ice is in the layers close to the surface. That’s good to know, because a planetary rover is going to be able to sample such environments much more readily than those several meters beneath. Also helpful is the team’s discovery that cleaning the rover’s sample scoop is harder than it looks, leaving dead micro-organisms on it even after it had apparently been sterilized. New procedures have resolved the problem, ensuring we don’t inadvertently ‘discover’ Earth organisms that have found their way along for the ride.

What happens as we move further out in the Solar System? It’s interesting to speculate on the status of microorganisms near the surface in a radiation-withered environment like that of Europa. But as Richard Greenberg has convincingly demonstrated in his book Unmasking Europa (Springer, 2008), the movement of ice on that world should bring material to the surface — search in the right place and life’s remnants may be close at hand. Now all we have to do is find the funding for a Europa lander (which may be harder to do than flying the mission itself), while developing sufficient radiation shielding to make it feasible. Astrobiology offers no shortage of challenges.