Scientists have located the ideal drill site for the first
ever exploration of an Antarctic sub-glacial lake, a development that is likely
to facilitate a revolution in climate-change research and that may lead to the
discovery of life-forms cut off from the main line of evolution for millions of
years.
In a recent paper published inGeophysical Research Letters,
scientists from Northumbria University, the University
of Edinburgh and the British Antarctic
Survey have revealed the optimal drill site for exploring Lake
Ellsworth, a sub-glacial lake
comparable in size to Lake Windermere, which
is covered by 1.8 miles of ice.
No one has yet drilled into an Antarctic sub-glacial lake.
But microbiologists believe that such lakes could harbor uniquely adapted
life-forms cut-off from other lines of evolution.
Paleoclimatologists
also suggest that sediments on the lake floors could contain records of ice
sheets and climate history that would revolutionize research into global
warming.
In order to access the lake water and the undisturbed
sediment containing the climate record, it is essential to drill in the right
place.
The optimal drilling site has to avoid possible areas of
in-coming water that would disturb the sediment, as well as areas of so-called
basal freezing – where lake water freezes to the underside of the ice. It also
has to avoid any concentrations of trapped gases that could rush up the borehole
to cause a potentially dangerous blowout at the surface.
The Scientific Committee on Arctic Research identified Lake Ellsworth
as an excellent candidate for the first drill site.
Dr. John Woodward, from Northumbria
University’s School of Applied Sciences,
comments: “The location provides a deep water column for sampling and reduces
the risk from possible basal-freezing mechanisms. It optimizes the chances of
recovering an undisturbed, continuous sedimentary sequence from the lake floor,
and minimizes the potential for trapped gases to gain entry to the borehole.”
Dr. Andy Smith of the British Antarctic Survey adds: “This
is an eagerly-anticipated result – the final piece of the jigsaw that we need
to plan the exploration of Lake
Ellsworth. That
exploration can now go ahead at full speed.”
To locate the optimal drill site, the team had to conduct
the first detailed characterization of the physiography of a sub-glacial lake.
Between 2007-2009, the lake was subject to a ground-based geophysics campaign
involving an ice-penetrating radar to investigate ice thickness, seismic
surveys to calculate lake water depths and flow measurements to calculate how
the ice sheet flows over the underlying lake.
The
climactic stage in the project will take place in the 2012-13 Antarctic summer
when the Lake Ellsworth Consortium will use the data in the paper to access a
sub-glacial lake for the first time.
