Antarctic test of novel ice drill poised to begin
It’s a chance to get the kinks out before an American team deploys the system in January to bore for the first time into a pristine, subglacial lake
ROSS ICE SHELF, ANTARCTICA — Any day now, a team of 40 scientists and support personnel expects to begin shoveling ice and snow into a melting bin. Over the next 24 to 36 hours, they’ll send the resulting 90 degree Celsius water down through a clean hose that they’ll unspool from above. They’ll use the warm, high pressure jet to bore a 30-centimeter hole through 83 meters of ice. Once it breaks through to the sea below, they’ll have a few days to quickly sample life from water before the hole begins freezing up again.
It’s only a test. But if all goes well, the group will immediately pack up their 13 vans and cargo containers and begin hauling them in a tractor-drawn caravan over the ice to a spot 700 miles away — to just past where the floating ice shelf meets the Ross Ice Sheet. At the site they’ve chosen, 800-meter-thick glacial ice is slowly advancing across land to the sea. Here, the ice doesn’t just cover rock. It also overlays a network of subglacial lakes.
And at some point in mid-January, the intrepid research crew representing a consortium of U.S. universities expects to unpack its equipment and unspool some 1,000 meters of hose to again drill through the ice. This time, they hope to puncture into Lake Whillans, searching for freshwater life that may have been living for eons outside even indirect contact with Earth’s atmosphere.
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The expectation, of course, is that anything they find will be microbial — bacteria, viruses or archaea. But if some toothy eel-like fish were to swim by, there will be a camera to capture its mug.
In the current tests, all of the many integrated systems will be given a shake-down run. There’s the system to power the whole enterprise: a pair of 225-kilowatt diesel-powered generators, notes Frank Rack of the University of Nebraska, Lincoln. They will slurp down some 1,000 gallons of that diesel per day. So part of the January caravan will be devoted to moving the fuel to power a tent city for quite a while out on the ice.
The project’s tank to hold the meltwater fueling the novel drill has a 3,700 gallon capacity. That’s more than enough to puncture through the ice, Rack says, since this water will be continuously recirculated into and up through the ice.
Biology labs are being erected next to the drill. Their job will be to survey for cells that might collect on fine filters sent down the bore hole. “I’m going to be using some microscopy to look for viruses,” says Tristy Vick-Majors of Montana State University in Bozeman. Others will survey for different microbial types, sometimes just by assaying for the presence of some type of DNA. Ultimately, she says, the goal is to identify what types of communities have developed in these deeply buried lakes — and what fuels their growth, because in their perpetually dark ecosystems, there can be no photosynthesis.
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I asked Vick-Majors how long it might be before she and her colleagues could establish the presence of any life beneath the ice? Almost immediately, she quipped. “As soon as the water comes out of the hole we’re going to take it into the lab, filter out the cells, stain them and put them under a microscope.” The initial findings won’t identify the germs by species, she says. But it will give biologists an idea of the community structures that have assembled.
Key to safely studying the community is ensuring that the drilling activities and samplers do not introduce any terrestrial contaminants. So every piece of equipment going down the hole will be blasted by a mixture of hot water and compressed air, followed by hydrogen peroxide. Filters will trap minerals and other contaminants 0.2 micrometers or larger that may be in the water. And as the equipment descends, everything will pass a bank of ultraviolet lights that bathes it with 40,000 microwatts per square centimeter of cell-killing energy. “Basically, this will just cook anything that’s on its way down,” Rack says.
Many of the pieces of custom equipment were only fabricated a few months back and shipped to the site. So during the upcoming test, “there are still some things that we will discover about the drill and how it operates that may differ from the design characteristics,” says Rack, whose team engineered the drill. “But we’re pretty confident it’s going to work well.”
Stay tuned for an update….
And here it is: Drilling commenced on December 17. The hot-water borer cut through 85 meters of ice to reach the Ross Sea one day later. On the 19th, the drilling team lowered an Instrumentation Package for Sub-Ice Exploration, or IPSIE, down the borehole. There it began collecting data and real-time video today. Two days after that, the scientists deployed a geothermal probe, sending it 1.5 meters into the seafloor sediment.
All in all, the researchers judged their experimental test-drive a success. Now the team is packing up their tools and mobile labs so that they can be shipped out to the ice sheet for the real deal: Boring through a half-mile of ice covering Lake Whillans.