A pioneering British expedition to sample a lake under the Antarctic ice hopes to find unknown forms of life and clues to future climate impacts. The mission will use hot water to melt its way through ice 3km (2 miles) thick to reach Lake Ellsworth, which has been isolated from the outside world between 125,000 and one million years. The team hopes to be the first to sample a sub-glacial Antarctic lake. The project, funded to the tune of £7m by the UK's Natural Environment Research Council, aims to obtain samples of the lake water itself and of sediment on the lake floor.
Understanding the West Antarctic Ice Sheet is seen as crucial to forecasting future climate change impacts, as it holds enough ice to raise global sea levels by between 3m (10ft) and 7m (23ft). Exploring sub-glacial lakes may also help scientists design missions to search for life on other worlds such as Jupiter's moon Europa, which is thought to feature a liquid ocean beneath a thick layer of ice.
The UK team has carefully designed its equipment and its procedures in order to avoid taking surface organisms down as they drill. "Just about everywhere we look on the planet, we find life, from the outer reaches of the stratosphere to the deepest ocean trenches," said Dr David Pearce from the British Antarctic Survey (BAS), who heads the search for microbiological life in Lake Ellsworth. "Any form of life we find there, we won't have encountered before - there will probably be viruses, and we may have bacteria, archaea (other single-celled organisms) and... maybe fungi." If the lake contains no life, said Dr Pearce, that would be interesting as well, helping to define the conditions under which life can and cannot exist. It means that transporting surface life into this pristine environment would be a disaster, that could not be undone.
An engineering team leaves the UK in the coming week with 70 tonnes of gear. The heavy equipment has to be airlifted in to Antarctica and then hauled over land to the drilling location. "Our project will look for life in Lake Ellsworth, and look for the climate record of the West Antarctic Ice Sheet," said the project's principal investigator Professor Martin Siegert 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 reporters.
Much of the equipment has been designed and built at the National Oceanography Centre in Southampton, under the supervision of Matt Mowlem. "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."
The equipment will be delivered to the Ellsworth base during the coming Antarctic summer, and stored away against the harsh winter. The main scientific party will fly out in about a year's time, unpack the equipment, and begin the hunt.