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Lake Ellsworth Antarctica
October 18, 2011
Geologists will travel great distances for their profession. The record holder in this regard is former
astronaut,
Harrison Schmitt, who went to the
moon on
Apollo 17.
Runners-up are likely the many geologists who have recently converged on
Antarctica to explore that pristine
continent buried under all that
snow and
ice. Of current interest are the many
lakes that are buried under
kilometers of ice. Antarctica's 387 known
sub-glacial lakes are
liquid because of the combined effect of the
geothermal heat of the
Earth and the
pressure of the ice layer.[1] The isolation of these lakes from the rest of the world for hundreds of thousands of years makes them an interesting object of study; and, perhaps, an object of a
science fiction thriller or two.
A team of
British scientists and
engineers has just begun an attempt to drill though the antarctic ice sheet into
Lake Ellsworth, a sub-glacial lake that's about 10 km long and 2-3 km wide (see map).[1-5] Taking heed from the
exobiologists, there's the possibility that various lifeforms will be found in the liquid water, or in the sediment at the lake's bottom. It's possible that unique
species of
bacteria,
fungi and
viruses will be found to have survived in the cold, dark environment.[1]
"X" Marks the Spot.
The location of Lake Ellsworth in Antarctica.
(NASA Image))
The Lake Ellsworth expedition, funded principally by a £7 million grant from the
UK Natural Environment Research Council and additional funds from the
British Antarctic Survey, has been planned for fifteen years.[1,4] This time of year, Antarctic summer, is the most ideal time to commence drilling, which is planned to start in December. It's only recently that technologies have been developed to allow drilling and sampling without contamination of the lake.[1] The operation uses "space-industry standard clean technology."[3]
The drill is essentially a hot water spray at the end of a 1.8 mile (3.2 km) hose. A
boiler will be used to create 90,000
liters of pure water from melted, then filtered, ice.[2] The spray nozzle delivers 2,000
psi water heated to 97
°C to create a 36
cm borehole.[2,5] After boring, a five meter probe will be lowered into the lake.
The
titanium probe will carry twenty-four sampling flasks, lights, a
high definition video camera, and filters to sample suspended solids in the water.[2]
Ground-penetrating radar and
seismic mapping studies have indicated that the lake has a soft floor that suggests a sediment layer several meters thick.[1,2] A
percussion corer will be used to sample the lake bed.[daily mail]
Since the water in the lake is liquid only because of its 300
atmospheres pressure and proximity to the Earth's geothermal heat, the water samples will freeze as they exit, exerting 2,700 atmospheres of pressure on their sampling containers.[2] The sampling operation needs to be completed within 24 hours. The cold antarctic temperatures will cause refreezing of the borehole water, reducing its diameter by about 6
millimeters per
hour.[2,5]
Photovoltaic panels at Lake Ellsworth Antarctica. Notice the unusual orientation of the panels, at least for temperate zone dwellers. The Sun's rays are horizontal.(Photo from Subglacial Lake Ellsworth Website))
The main object of the Lake Ellsworth expedition is recovery of the possible relic organisms that might have survived in isolation from the rest of the planet for hundreds of thousands of years. A few hundred thousand years is not a very long time,
geologically speaking, but the
evolution of
microorganisms proceeds rather quickly.
The US has plans to investigate
Lake Whillans, and the
Russians have been attempting a similar operation on the other side of the continent, at
Lake Vostok, the largest sub-glacial lake.[2] The Lake Vostok project has had problems, and drilling was suspended in February of this year, at the advent of the Antarctic winter, when the Lake Vostok borehole was within fifty meters of the lake.[7]. The drilling is expected to resume soon.
Lake Vostok is a more interesting target, since the lake has been isolated for fifteen million years. [8] It's also a more difficult target, since the lowest recorded temperature on Earth was measured there, -129°F (-89.4°C).[8]
Radar image of Lake Vostok.(NASA satellite radar image))
References:
- Steve Connor, "To coldly go... British team to drill into lost Antarctic world," Independent (UK), October 11, 2011.
- Richard Black, "Antarctic lake mission targets life and climate signs," BBC News, October 10, 2011.
- Leon Watson, "The final frontier... British explorers seek out new life in a lost world hidden for up to a million years beneath the frozen Antarctic wastes," Daily Mail (UK), October 11, 2011.
- Nick Collins, "Antarctic underground lake could hold secrets of Earth's past," Telegraph (UK), October 11, 2011.
- Olivia Solon, "Geologists Prepare to Drill Into Ancient Antarctic Lake," Wired News, October 11, 2011.
- Subglacial Lake Ellsworth Website.
- Lake Vostok Drill On Hold, The Voice of Russia, February 7, 2011.
- Alissa de Carbonnel and David Randall, "Earth's last great virgin habitat invaded - A borehole through Lake Vostok's polar ice could reveal hidden lifeforms," Independent (UK), February 6, 2011.
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