Thursday, 15 February 2007, 19:45 GMT
By Jonathan Fildes
Science and technology reporter, BBC News, San Francisco
Satellite images reveal the changes in volume of water (Link to larger version at link below)
Giant "blisters" containing water that rapidly expand and contract have been mapped beneath the Antarctic ice sheet.Fed by a complex network of rivers, the subglacial reservoirs force the overlying ice to rise and fall.
By tracking these changes with Nasa's Ice Cloud and land Elevation Satellite (ICESat) scientists were able to map the extent of the subglacial plumbing.
The results, published in the journal Science, show that some areas fell by up to 9m (30ft) over just two years.
"We didn't realise that the water under these ice streams was moving in such large quantities, and on such short time scales," said Dr Helen Fricker of the Scripps Institution of Oceanography, University of California, and one of the authors of the paper....
(more at link)
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