British Scientists Begin To Drill Antarctic Ice Sheet To Hunt For Life
[Watch Video: Tractor Train From Union Glacier To Lake Ellsworth]
Lawrence LeBlond for redOrbit.com – Your Universe Online
A British team of researchers is about to drill for life in Antarctica. It is a project that has been in the making for more than 15 years and is now becoming a reality for 12 scientists and engineers who want to explore an ancient lake deep below the Antarctic ice sheet. But getting there requires drilling through 2 miles of ice.
The site, Lake Ellsworth, was discovered in 1996 by British scientist Martin Siegert, who is part of the current mission. The lake is one of 387 known subglacial bodies of water in Antarctica and experts believe it is the best candidate for the search for microbial life. Finding life in these dark, nutrient-poor, atmosphere-deprived waters would be significant, as scientists have speculated any life that has evolved here would have been isolated for the last half-million years.
The drilling, which starts today, is a delicate process. The $12-million operation utilizes nearly 100 tons of equipment, including a high-pressure hose with sterilized water near boiling point to blast through more than two miles of ice. Initial drilling will be done in short bursts as they test out the equipment.
Chris Hill, program manager at the British Antarctic Survey for the project said the team hopes to reach the lake by Sunday.
“Since that boiler fired up, the mood’s been pretty good,” Hill said in a satellite phone interview with Bloomberg. “We have to wait on this like expectant fathers.”
Siegert explained that the initial process will be to open a bore-hole, which will take about five days. Following that process, the crew plans to start a rapid sampling operation before the ice refreezes. He told the BBC’s David Shukman that “everything has to be done in ultra clean conditions.”
“We don’t want to contaminate this pristine environment – and unless we keep the experiment very clean, we’re likely just to measure the things that we bring down us with, which would be pointless,” he added.
The goal of the mission is to recover water and sediment samples from the lake to determine if life exists there and also to offer clues on the continent’s climate history in ancient times.
“The most likely organisms to be found will be bacterial – - they’re everywhere,” David Pearce, a microbiologist at the program said in an October interview, shortly before heading to the southern continent to begin preparations. “If there’s nothing there, that will tell us the limits for the existence of life on Earth.”
Andy Tait, the engineer in charge of the drilling process, also described the operation as “delicate.” He explained that while the technology of hot-water drilling “has been used extensively by scientists in the past, this is the first time we’ve ever attempted to go through [2 miles] of solid ice – this will be the deepest borehole ever made this way.”
Tait said that the boilers are fired up to around 194 degrees F and water pressure comes out of the hose at around 2,000 PSI—or about 15 to 20 times more powerful than the pressure found in car wash hoses.
After initial drill tests, the team will bore down about 1,000 feet and create a water-filled cavity to help balance the water pressure between the lake and the hole. Then, they will start a new hole from the top and bore down to the cavity and then on down to the lake.
Once the holes are drilled, the process gets tricky. Hill said researchers have a relatively short window of 24 to 30 hours to recover samples before the hole freezes and becomes too narrow to safely lower and then remove instruments.
After drilling, the first instrument to be lowered into the hole will be a sterile ultraviolet lamp to irradiate any life around the edges of the hole, said Hill during the October mission briefing. The second instrument to be lowered will be a probe with canisters that will collect water samples from different depths. Finally, a sediment corer will be lowered down to recover sediment from the lake bed. Scientists hope by getting sediments from the lake bed, they will be able to tell whether the ice sheet has retreated in the past, which could be indicative if they find any fossilized organisms deeper in the silt.
Siegert said exploring for life in such an extreme environment—in pitch-black conditions under high pressure beneath the ice sheet—could open up possibilities for life in other extreme environments, such as Jupiter’s moon Europa.
“The experiment we’re doing is very similar to an experiment one might do to see whether there is life on Europa,” explained Siegert in the BBC interview. “We know Europa has an icy crust and an ocean beneath it. If there’s life on Europa it’ll be living in a very similar way to life in Lake Ellsworth with total darkness, lots of pressure and using chemical processes rather than sunlight to power biological processes.”
Hill said researchers will be able to study the samples nearly as soon as they are returned from the deep. Other samples will be shipped back to mainland UK, where they will be further scrutinized by laboratories around the country. He said the first scientific papers on their findings could be published by late 2013 or early 2014.
If everything goes smoothly and the conditions are manageable, Hill told Bloomberg that the team will re-drill and lower a second set of instruments down for more samples. Hill said the five-day forecast predicts low winds and some cloud cover. The Antarctic summer usually sees temperatures hovering around 0 degrees F during the day, with night-time temps dipping to -35 degrees with a wind chill.
The project, 16 years in the making, would likely not have surfaced if it weren’t for radio echo-sounding data compiled by Siegert in the 1990s. Siegert, a glaciologist at the University of Edinburgh, was the first to uncover Antarctic’s lakes through his research. Lake Ellsworth, which Siegert discovered in 1996, was first identified as a potential target for exploration around 2004.
The multi-million-dollar project is being funded by a consortium of UK universities.
A Russian team became the first to drill the ice sheet for life back in February. They drilled through more than 2 miles of ice to reach the water of Lake Vostok. That group collected samples of “fresh frozen” water, according to the country’s Arctic and Antarctic Research Institute. No findings have been published on that project as of yet.
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2012-12-12 19:40:29
Source: http://www.redorbit.com/news/science/1112746829/scientists-drill-antarctic-ice-life-121212/
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