Antarctica's Lake Vida, a geologic curiosity that essentially is an ice bottle of brine, is home to some of the oldest and coldest living organisms on Earth. Perpetually covered by more than 60 feet of ice, the brine below – water that is five to seven times more salty than seawater – has been found to be home to cryobiological microbes some 2,800 years old which were revived after a gradual thaw.
That widely reported finding came in 2002 from Peter Doran,
associate professor of earth and environmental sciences at the University of
Illinois at Chicago. But the discovery raised many new questions. Now, Doran
and his department colleague Fabien Kenig with collaborators from the
Nevada-based Desert Research Institute will return to Lake Vida late next year
for more exploration, funded by a $1.1 million National Science Foundation
Doran and Kenig plan to perform the first-ever drilling
entirely through Lake Vida's thick ice cap, into the brine, and down into
sediment below, retrieving about 10 feet or more of core sample for analysis.
"The main goal is to get into that brine pocket and the
sediment beneath it to both document and define the ecosystem that's there
today, and the history of that ecosystem," Doran says.
The sediment samples could yield clues about life in such an
extreme environment dating back thousands of years, which could help
geoscientists draw a better picture of processes that occur as the Earth moves
into colder periods.
"If we took, for example, a Wisconsin lake and started
turning the temperatures down during a climatic downturn, what is the impact on
the lake's ecosystem, and what strategies are used by living things to survive
this extremely cold brine?" Doran says of the salty liquid that hovers
around 10 degrees Fahrenheit year-round. "There are few examples on Earth
of things shown to live in that water temperature."
A University of Wisconsin group will drill the ice hole, but
special care will be required in preparing the site. A tent will be partitioned
to provide both a drilling site cover and adjacent laboratory to analyze
samples. It will be sort of like setting up a hospital operating room in the
Antarctic cold, with the drill requiring the sanitary cleanliness of a
surgeon's scalpel to prevent any surface contaminants from ruining samples.
Kenig, an organic geochemist, will study the lake's carbon
and organic chemistry, as well as molecular fossils in the sediment core. These
preserved organic compounds will point to changes in the ecosystem as the lake
"As this environment was isolated for some time, we
need to be very cautious not to introduce any external elements that could bias
our samples," Kenig says. To assure sample purity, nothing plastic or
rubber will be used in the drilling, and all equipment penetrating the lake
water and sediment will be sterilized.
While specially preserved samples will be shipped back to
UIC and the Desert Research Institute for later analysis, some work, such as
microbial counts, will be done on site. Doran's previous on-site research at
Lake Vida found in the ice the highest concentration of nitrous oxide –
laughing gas – of any ecosystem on Earth. It was a clue that would make any
gas is produced by microbes," Doran notes. "That was a hint that we
had a viable ecosystem there."
Drilling Deeper Below Antarctica's Lake Vida
September 24, 2009