Antarctic Drillers Seek Clues to Life Two Miles Below Ice
A British-led team of researchers is racing against time and the elements as they drill through 3.2 kilometers of Antarctic ice to search for new forms of life on Earth.
Lake Ellsworth is a body of liquid water trapped between ice and bedrock 3.2 kilometers (2 miles) beneath the surface of Antarctica. One of more than 350 known sub-glacial Antarctic lakes, it’s been isolated from the terrestrial biosphere for at least several hundred thousand years. The operation, which has an 8 million pound (almost $13 million) budget and is using about 100 tons of equipment, is designed to help scientists better understand the ecological limits that can support life and make discoveries about the frozen continent's past climate.
In October, I caught up with the British Antarctic Survey's Chris Hill, Program Manager of the Lake Ellsworth drilling program, and David Pearce, a BAS microbiologist working on the search for life in the samples BAS retrieves. Speaking in separate interviews, they told me about the pitfalls of working in Antarctica's harsh environment, the space-grade technology and hot-water drills they're using, and the lengths they’re going to ensure they don’t contaminate the lake. Publishable results might come by early 2014.
Q: What do you think you might find?
Chris Hill: What we're most likely to find in terms of life is some sort of microbial life. It's what biologists refer to as extremophiles, which are microbes that have adapted to very extreme environments.
The interesting thing will be to see whether those microbes are thriving in that environment or whether they’re just clinging on at the very edges of existence. If we find just a sterile body of water that will almost be more interesting.
Life finds its way to exist in every environment on this planet where there is water. If we find the first body of water on the planet that has no life in it, we can start to write the book on what the limits of life are, which has huge implications for outer space exploration.
David Pearce: It’s ultimately the search for life. Is there life, and if there is, what form does it take, how does it survive, what constraints does it have.
The second question is to find out about the stability of the West Antarctic Ice Sheet from the sediment. Primarily, whether the ice sheet melted in the past or not.
Q: Are there any applications for what you’re doing?
David Pearce: Limitless. As scientists we're governed by politics and funding. The next stage in sub-glacial exploration will depend on what we find. If we find organisms that are common in the rest of the world, well that's interesting, but it doesn’t tell us very much.
If we find unusual organisms, why is it unusual and what is it about them that can be useful to us? They might have biochemistry that enables them to change chemicals in the atmosphere in ways that we haven’t thought of before.
They may contain antibiotic molecules that we hadn’t encountered before and they use in competition with other bugs down there that we could adapt and use in biotechnology.
Q: The nail-biting element of this operation is that you have to take your samples before the hole refreezes. How are you planning to use that time? How do you know any organisms in the samples aren’t contaminants from the journey up or the surface?
Chris Hill: So we reach the lake, we take the drill out of the hole to clear the hole for the instruments. Once we've removed the drill, of course, we've removed the heat source, which is the only thing keeping the hole open, so the clock starts ticking.
The first thing we deploy is a very, very strong ultraviolet light so that if there's any microbial life at the edges of the hole, we can just irradiate it.
The moment it comes out, the cap is sealed on the wellhead and that is now closed -- it’s a completely sterile hole. Everything then that goes down the hole goes through an airlock. It’s almost like NASA space technology here. We're creating complete airlocks at every stage and nothing can get in or out.
Q: You’re confident you’re not going to get any contamination?
Chris Hill: We're absolutely confident we've gone above and beyond what’s required of us to keep this lake as clean as we possibly can.
Q: What stops the water gushing up from the lake or the snow melted for the drill from going down to the lake?
Chris Hill: It's essentially a pressure-balancing act. We can reasonably approximate the pressure the lake is at -- 310 bar of pressure. The challenge is to equalize that by creating 310 bar of pressure in the hole.
The beauty of this is if we get it wrong, the water in the hole is sterile. We're going to filter that snow. We have a bank of four filters, four stages. The final stage of that is 0.1 microns, which is double the standard the pharmaceutical industry uses. And then we're going to run that same water through an ultraviolet chamber so that if anything's made it through the filters, we're going to kill it.
Q: Tell me about the sampling probe you're sending down:
Chris Hill: It contains 24 individual sample bottles of 100 milliliters, each of which can be fired completely independently. So we can gather a water sample from 24 different depths down the lake. In reality what we'll probably do is gather them in triplicate -- so we'll get three at one depth, three at another depth and so forth.
David Pearce: Where we're going it's about 160 meters deep. We're using one bottle for microbiology, one bottle for organic geochemistry, and one for hydrochemistry.
The organic geochemistry tells us what organic molecules are present in the water, and these can be indicative of life and what it’s doing now. The hydrochemistry tells us about the physical and chemical conditions of the lake water; whether it’s oxic or anoxic.
Q: What happens once the water samples come up?
Chris Hill: We take our samples and recover that instrument back to the surface, back into sterile containment. We then deploy the sediment corer. It has one job. To go to the very bottom of the lake, to position itself right on the lake bed, on the sediment, and to hammer out a three-meter barrel to give us a three-meter core of the sediment of the lake.
Hopefully that should take a matter of minutes. We've got cameras top and bottom.
Q: You'll drop two sets of samplers and corers down if you have time. Do you need to redrill the hole?
Chris Hill: I think we will. We'll have a window between 24 and 30 hours to get our samples. We think we can deploy and recover the probe in approximately 6 to 8 hours. The corer should be a bit quicker, more like 4 to 6 hours. Then obviously we have the sterile UV lamp at the start, which will be about 6 hours as well. When you start adding those up, you don’t have a lot of margin.
We need [an opening of at least] 200 millimeters (almost 7.9 inches) for the instruments. The hole starts out at 400 millimeters. After 24 hours it’s down to about 300 millimeters, and that's about as far as we want to go so it doesn’t get stuck. We've got a 3.2-kilometer hole. We need to make sure we can get these instruments out. It would be a disastrous if we got halfway up and it got jammed. So we've built in significant tolerances so we can recover everything.
Using the second set of probes wouldn’t be down to time, it would be down to fuel. Everything is fuel dependent. It all burns on jet aviation fuel. The reason for that: it's reasonably safe, has a high flashpoint, and is really clean. Of all the fuels you can burn down there it has the least emissions.
Q: What are the potential pitfalls?
Chris Hill: There are a lot. Working in Antarctica is extremely risky. Many field camps in Antarctica if they wake up and the weather's particularly bad, they'll just take a day off. We can’t do that once we've started this process. If we stopped it and took the heat source away, the water would freeze in the pipes and that would be game over.
Once we make the decision to start we have to commit to it and stick to it all the way through.
Q: It must be fascinating being involved in a project like this.
David Pearce: It's the pinnacle of a career. It's taken me 15 years training to get to a stage where I can do this. The whole project has taken about 10 years from its inception to get to the stage where we're ready to go into the field. Everything's got such a long lead-in time. So it’s a bit like a space mission. You work at it for years and years and years, you get one shot at it and that either works or it doesn’t work. And if it does work, the data you get, you can spend the rest of your career analysing it. If it doesn’t work, you’re back to the drawing board and starting work again. If it all comes off it'll be really exciting. I compare it to finding life on another planet.
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