Researchers found a diverse community of bugs living in the lake's dark environment, at temperatures of -13C.< Furthermore, they say the lake's life forms have been sealed off from the outside world for some 2,800 years.< Details of the work have been outlined in the journal PNAS.< Lake Vida, the largest of several unique lakes found in the McMurdo Dry Valleys, contains no oxygen, is acidic, mostly frozen and possesses the highest nitrous oxide levels of any natural water body on Earth.< A briny liquid that is approximately six times saltier than seawater percolates throughout the icy environment.< Dr Cynan Ellis-Evans, from the British Antarctic Survey (Bas), who was not involved in the recent research, told BBC News: "There are various lakes that are very salty down there... but this is a really freaky one.< "It's almost frozen solid right to the bottom. But you've got this brine 'mush' in the centre. For several years, they've been trying to get into it."< He said the discovery of microbes at such low temperatures was "a very interesting discovery".< Antarctic lake's clue to alien life