October 11, 2011
Scientists To Study Underground Lake In Antarctica
An Antarctic lake hidden under 1.8 miles of ice in the western region of the continent could reveal what life on Earth looked like a million years ago and could narrow down the search for extraterrestrial life, as well as give scientists clues to future climate impacts, according to a British expedition taking up the study.
Expedition members will use hot water to melt down through the nearly 2-mile-thick ice to reach Lake Ellsworth, which has been isolated from the outside world for more than 100,000 years -- perhaps as long as a million.
Lake Ellsworth is most likely to contain bacteria, microbes and other simple life forms that experts believe have had no influence from the rest of the natural world for up to a million years. Samples from the lake could reveal undiscovered species of life which existed before the lake froze over, and give scientists a possible picture of what the climate was like in the past.
Sediment collected from the lake bed is expected to support the theory that the West Antarctic Ice Sheet, which is currently on the wane due to global warming, has melted and collapsed in the past.
Scientists also hope to learn how any life is able to exist in such an extreme environment such as Antarctica -- which could aid astronomers in their search for life beyond Earth.
“Our project will look for life in Lake Ellsworth, and look for the climate record of the West Antarctic Ice Sheet,” said Professor Martin Siegert, the project´s principal investigator, who hails from Edinburgh University. “If we're successful, we'll make profound discoveries on both the limits to life on Earth and the history of West Antarctica,” he told BBC News.
Understanding the West Antarctic Ice Sheet is critical in order for better forecasting future climate change impacts, as it holds enough ice to raise sea levels by at least 10 feet around the world, and possibly as high as 23 feet.
A similar project has been in operation at Vostok, another underground lake in Antarctica, by Russian scientists. But that project has suffered many delays and technical setbacks for several years. The British team, hoping for better success, aim to drill through the ice, obtain the samples and bring them to the surface in a matter of hours.
The expedition marks the peak of a 15-year project by British universities, the British Antarctic Survey and the National Oceanography Center. A party of four scientists led by Chris Hill of the British Antarctic Survey will depart next week to begin transporting the equipment to the site, so the project can begin next October.
The team´s first battle will be making the 10,000 mile journey to the site above Lake Ellsworth, which is about the size of England´s biggest lake, Lake Windermere. Once in place, they will utilize a specially-designed hot water drill to bore down into the lake. A probe about the width of a CD will then collect, filter and analyze samples of the water within the lake. A second piece of equipment will be lowered down the shaft to hammer into the sediment on the lake´s bed and collect more samples.
Scientists expect the drilling process will take about eight hours, but the team will spend about three months living in tents at the site, studying and analyzing whatever samples they can bring back up.
“For almost 15 years we have been planning to explore this hidden world. It´s only now that we have the expertise and technology to drill through Antarctica´s thickest ice and collect samples without contaminating this untouched and pristine environment,” Siegert told BBC News.
Dr. David Pearce, of the British Antarctic Survey, said uncovering a “relic population” that has been isolated from the rest of the world for hundreds of thousands of years could “give us some insight into what early life might have been like on Earth.”
“Here we have one of the final frontiers for the search for life on our planet ... we just don't know what might be there but we can predict it is highly likely to contain some form of life,” he told the Telegraph. “There may well be relic populations down there that have carried on doing what the first microorganisms would have done ... it will give us some insight into what early life might have been like on the Earth.”
Finding nothing at all would be even more significant, he added, because it would “define limits at which life can longer exist on the planet.”
Lake Ellsworth is kept liquid by natural geothermal heat coming from the Earth´s interior. The lake has been mapped out by using ground-penetrating radar and seismic tests. The investigations revealed that the lake has a soft floor, which means there should be a thick layer of sediment.
Matt Mowlem, a supervisor at the National Oceanography Center, said the equipment being used for the project was specifically designed and built for the harsh-climate project. “This is an unknown environment - we don't know for example whether there will be dissolved gases in the water,” he said.
“So the water at its pressure of 300 atmospheres will be sampled. But when we pull the probe up and the flasks hit the cold air in the borehole, the water will try to freeze; the pressure then increases to around 2,700 atmospheres, and that's greater than anything experienced in ocean engineering,” he explained.
Once the probe is hauled up, a coring device will be lowered down the borehole to take more samples. The whole process is a race against time, he added.
Water on the sides of the borehole will freeze quickly, making the hole progressively smaller. Siegert estimates there is a window of about 24 hours to complete the dual sampling before the holes becomes too small.
The team hopes all works out according to plan. After all equipment is delivered to the Lake site during the coming Antarctic summer and is properly stored to survive the harsh winter that follows, the main party will head out, around next October, unpack the equipment, and begin drilling into the unknown.
Image Caption: Ellsworth Mountains. Credit: British Antarctic Survey
On the Net
- Project website
- Natural Environment Research Council
- British Antarctic Survey
- National Oceanography Center