An ambitious British plan to search for minute forms of life in an ancient lake beneath Antarctica's ice has been suspended because of technical problems, the scientist leading the project said on Thursday.
In a move that clears the way for U.S. and Russian teams to take the lead, Professor Martin Siegert said technical problems and a lack of fuel had forced the closure on Christmas Day of the 7-million-pound ($11 million) project, which was looking for life forms and climate change clues in the lake-bed sediment.
"This is of course, hugely frustrating for us, but we have learned a lot this year," said Siegert of the University of Bristol, principal investigator for the mission, which was headed by the British Antarctic Survey (BAS).
"By the end, the equipment was working well, and much of it has now been fully field-tested," he said on the BAS website.
Experts from Britain's Lake Ellsworth mission had expected to find minute forms of life in the lake three km (two miles) under Antarctica's ice, the most remote and extreme environment known on Earth.
They had also hoped that by dating bits of seashell found in the water they would have been able to ascertain when the ice sheet last broke up and to better understand the risks of it happening again.
The U.S. team is aiming to start drilling in Lake Whillans, one of 360 known sub-glacial lakes in Antarctica, in January or February 2013.
Russia was the first to pierce 3,769 metres (12,365 ft) of solid ice to reach Lake Vostok early in 2012. But some scientists believe their samples may have been contaminated by drilling fluids.
The British scientists decided to abandon the mission after trying for 20 hours to connect two holes in the ice that were needed for the hot-water drill to work, said a BAS spokeswoman.
Without a connection between the two holes, the hot water would seep into the porous surface layers of ice and be lost, reducing the pressure and rendering the drill ineffective.
The team tried to melt and dig more snow to compensate for the water loss, but without success.
As a result of the extra time taken to fix the problem, fuel stocks had been depleted to such a level as to make the operation unviable.
Asked how long the delay might be before the project could be resumed, Siegert told the BBC: "It will take a season or two to get all our equipment out of Antarctica and back to the UK, so at a minimum we're looking at three to four, maybe five years I would have thought."
However, he said he felt this year's mission had not been a complete loss.
The BAS spokeswoman said: "It's very possible that either the U.S. or Russia may take the lead but I think the one thing we've learned here is that anything can go wrong."
"We've never depicted this as a race. All sub-glacial lakes would give different information," she said.