Using various methods, including airborne radar surveys, scientists have built a knowledge base about Antarctica's subglacial hydrological system over the past 40 years. The largest of the subglacial lakes, subglacial Lake Vostok in East Antarctica, is one of the largest lakes on our planet in terms of volume and depth and has been isolated beneath the ice sheet for more than 10 million years.
Samples of microbes from Lake Vostok have been collected indirectly by examining ice collected above the liquid part of the Lake- ice that refroze--accreted--on the bottom of the ice sheet.
These samples, which were described in 1999 by Priscu, the chief scientist of the WISSARD project, and David Karl, of the University of Hawaii, presented the first evidence for life beneath the huge Antarctic ice sheet.
However, the drilling techniques used to retrieve the Vostok samples and the low amount of microbial biomass present in the samples have called into question previous studies that concluded the lake supports a living ecosystem.
The WISSARD team drilled into subglacial Lake Whillans using a clean hot-water drill and incorporated rigorous measures to avoid the introduction of foreign material into the lake.
The approach to drilling was guided by recommendations in the 2007 National Research Council-sponsored report, "Exploration of Antarctic SubglacialAquatic Environments: Environmental and Scientific Stewardship," aimed to protect these unique environments from contamination.
A team of engineers and technicians directed by Frank Rack, of the University of Nebraska-Lincoln, designed and fabricated the specialized hot-water drill that was fitted with a filtration and germicidal UV system to prevent contamination of the subglacial environment and to recover clean samples for microbial analyses. In addition, the numerous customized scientific samplers and instruments use
|Contact: Dawn Jenkins|
Louisiana State University