British geologists and explorers near Lake Ellsworth.
Credit: British Antarctic Survey
Along with all the
festivities surrounding the anniversary of explorer Robert Falcon Scott's reaching the South Pole on 17 January 1912, Antarctic researchers are at the edge of their seats waiting for news that will merit another celebration. The centennial coincides with an expected
new landmark: This week, a Russian team drilling into Lake Vostok in the center of the Antarctic continent is likely to break through the ice to water.
It will be the first time that a subglacial lake has been breached. These modern-day explorers hope to discover whether Vostok, which at 5000 km3 is the third deepest lake on the planet, is teeming with hidden, cold-loving life that could have evolved separately from the rest of the
world for hundreds of thousands of years.
Microbiologist John Priscu of Montana State University in Bozeman, who was one of the original planners of the Vostok mission, has been getting regular
updates from the Russian team. As of 13 January, they had reached a depth of 3737.5 meters, about 15 meters away from liquid water. With three teams
drilling around the clock and making progress at an average of 2 meters per day, Priscu says they're on track to break through within the week. "This
is an epic event. I really wish them luck," he says. "I wish I was out there with them."
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After drilling 3720 meters last February, time ran out for the team and the
project was stymied just 29.5 meters from its destination as winter set in. Over the summer, they modified their drill bits and now the team is back at work with plenty of time to spare. They had left the large hole filled
with antifreeze, so it was ready and waiting for them. It will remain open for years to come, Priscu says, potentially allowing other teams to sample
the waters in the future.
It's a nerve-wracking moment for the drillers, however. The lake water is under immense pressure, making it imperative that the team's calculations are
correct. In the worst case scenario, Priscu says, "water could come up the hole and degas explosively, blowing out the whole borehole."
Now that the team is at the interface of the water and ice, the ice is very warm and forms large crystals that are challenging to drill through and
caused the team's drill to get stuck last year. But the modifications they've made seem to be working so far, Priscu says. The team will switch drill
bits from the large one that takes ice cores as it goes to a smaller one only a few centimetres in diameter, which will melt its way down using a
sterile silicone fluid. The team will then leave the lake water to rise about 50 meters into the hole and freeze; when they return next winter, they
will be able to retrieve this core and examine it for microbial life.
As exciting as the breakthrough is, this water sample will be "like going to the Pacific Ocean and putting a sampling bucket over the side of a ship
and saying this is what the Pacific is like," Priscu says. Recent publications analyzing the Russian ice cores have suggested the presence of
heat-loving microorganisms called thermophiles, suggesting hot geothermal vents like those in the ocean may exist at the bottom of the lake. That opens
the possibility of the presence of larger life, such as tubeworms and crabs, that had evolved in isolation for thousands of years, Priscu says. But reaching those depths would be extraordinarily
difficult to do without contaminating the lake—a major concern for the drilling team that they have taken great measures to avoid.
The Russians aren't the only ones planning to breach an Antarctic lake. A British team directed by
University of Edinburgh glaciologist Martin Siegert of the British Antarctic Survey returned from Antarctica's Lake Ellsworth last week, where it
dropped off a drill, 3400 meters of hose, a giant hot water boiler, and four 1.5 megawatt generators. This fall, the researchers will return and drill
into the lake, collect water samples, and analyze them, all within 3 days. Theirs is a different approach from the Russians': rather than using a giant
drill bit to make a permanent hole, they will be melting their way through with hot water, leaving a hole that's open for only about 48 hours in which
they can take water samples before it freezes shut. But unlike the Russian team, they hope to get answers on the presence of microbial life right away,
Siegert says, as they'll be analyzing the contents of each bottle of lakewater as they get it. "We've been planning Ellsworth for 10 years, for a day
of drilling and a day of labs," he says.
Priscu is looking forward to a similar U.S. effort called the Whillans Ice Stream Subglacial Access Research Drilling project next year, which will use a similar approach of
melting a hole with hot water in order to reach the river-fed Whillans Ice Stream in West Antarctica. "It's just going to be fantastic when [the teams]
get that first profile," he says. "It will transform the way we view the continent."
"It's hard not to think of yourselves as pioneers," Siegert says "At this moment, we're looking back 100 years to [Robert Falcon Scott's] expedition.
In another hundred years' time, we'll look back and think [our] experiments are basic. But there is a feeling we're exploring things that have never
been seen before and an awareness that, on our planet, that kind of work can only continue for so long."
*This item has been corrected 20 January. Vostok is the third deepest lake on the planet, not the third largest.