Geoscientist Martin Siegert, of the University of Bristol in the UK, discovered Lake Ellsworth in 1996 and is the principal investigator in a collaborative British effort to explore it. He says that drilling through three kilometers of ice to reveal the secrets of an entombed lake was never going to be easy.
Jon White: Why do you want to drill through three kilometers of ice to tap Lake Ellsworth, which has lain undisturbed for half a million years?
Martin Siegert: We are trying to test two hypotheses: that life exists in ancient deepwater subglacial lakes, and that sediments on these lake floors contain important climate records, potentially revealing the history of the West Antarctic ice sheet.
Jon White: Why did you have to stop the pioneering hot-water drilling on Christmas Day?
Martin Siegert: Our procedure was to drill down three hundred meters with a short hose and pause it there to create a cavity of water, which would then be pumped to the ice surface and used to supply water to the main hose, 3,400 meters in length. Once the cavity was established, the main hose was drilled to three hundred meters and should have connected to the cavity. This is necessary as the pump in the short hose could then be used to regulate the pressure in the main borehole— vital prior to lake entry. The problem was that the main hose did not connect to the cavity. Our attempts to do this reduced our fuel supply to the point where we could no longer reach the lake, even if we did connect to the cavity.
Jon White: How did it feel to make that decision, after so many years of preparation?
Martin Siegert: It was a really sad moment, but the information we had was easy enough to interpret and the call to stop was unavoidable. The annoying thing is that despite our difficulties, we were very close to being successful. If we had linked the cavity, the drill to three thousand meters was not a technical challenge.
Jon White: What happens next?
Martin Siegert: We are determined to learn from our experience and to put the lessons learned to good use in a revised plan. Realistically, this is likely to take three to five years, as equipment needs to come back to the United Kingdom, be serviced and modified, and then reinstalled in Antarctica. We really do wish to see it through to completion. Science is often characterized by setbacks. Our challenge is to deal with these professionally and to make sure that when we try again we are successful.
Jon White: What positives do you take home with you?
Martin Siegert: We've learned a great deal. No one has drilled this far before using the technique. We have trialed the whole system in Antarctica and it works well. Our field site and its logistics are well suited to the experiment. Our probe deployment system was field-trialed. Our sterility protocols work well. In fact, bar the issue with the cavity, the actual running of the experiment worked very well. We have much to be positive about, although of course we are hugely disappointed that we didn't do what we wished to this time.
Jon White: Might your efforts inform plans to check the frozen oceans of icy moons in the solar system for signs of life?
Martin Siegert: Our need for cleanliness is certainly similar to that used in space science, and the experiment itself is comparable: using a remote device to measure and sample an extreme environment. I think there is a lot that future space missions might learn from our work, which is one of the reasons for us to be so open about things, both good and bad!
Rico says he's sure it was a sad (and expensive) day...
No comments:
Post a Comment