Space radar reveals Antarctic rivers
02 May 2006
Scientists have known for decades about many huge lakes that hide beneath the frozen wastes of Antarctica. However, it has usually been assumed that the lakes were isolated. Now a European radar satellite known as ERS-2 has shown that rivers under the ice may transfer huge volumes of flood water from one lake to another.
The discovery was made by British scientists, who were analysing changes in the surface height of the ice sheet. Ultra-precise radar measurements of surface elevation revealed that the ice above one lake had sunk by about three metres. Two hundred and ninety kilometres away, above two different subglacial lakes, the ice had bulged upwards.
These changes in ice elevation can be explained if a river as big as London’s Thames was flowing beneath the 4-km-thick ice sheet. Over a period of 16 months, about 1.8 cubic kilometres of water raced along a tunnel carved in solid ice
“This new data shows that, every so often, the lakes beneath the ice pop off like champagne corks, releasing floods that travel very long distances,” said Prof. Duncan Wingham (University College, London).
“A major concern has been that by drilling down to the lakes new microbes would be introduced,” said Prof. Wingham. “Our data show that any contamination will not be limited to one lake, but will over time extend down the length of the network of rivers.
“We had thought of these lakes as isolated biological laboratories. Now we are going to have to think again.”
