Rivers as big as the Thames in England that may connect subglacial lakes have been found deep under the Antarctic ice, scientists said Wednesday.
British researchers who discovered the plumbing system that moves water hundreds of miles said it challenges the notion that the lakes under the Antarctic ice evolved independently and could support pristine ancient life.
"Previously, it was thought water moves underneath the ice by very slow seepage," said Professor Duncan Wingham of University College London, who headed the research team. "But 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."
Scientists had plans to drill through the ice to take samples from the lakes but were worried about contaminating them with new microbes.
"We had thought of these lakes as isolated biological laboratories. Now we are going to have to think again," Wingham added in a statement.
The research, which is reported in the journal Nature, also means that water from the subglacial Antarctic lakes, which were first discovered in the 1960s, could have flowed into the ocean in the past and that it could happen again.
About 150 subglacial lakes have been discovered in Antarctica, but researchers believe there could be thousands. Lake Vostok, at 15 million to 20 million years old, is thought to be the most ancient.
Scientists from University College London and Britain's Natural Environment Research Council Center for Polar Observation and Modeling found the rivers by examining changes in measurements taken by the European Space Agency's ERS-2 satellite over a region in East Antarctica known as the Dome Concordia.
They suspect the changes in the ice sheet show a flow of water from one subglacial lake to others.
"The lakes are like a set of beads on a string, where the lakes are the beads connected by a string or river of water," said Wingham.
The scientists believe when the pressure in one of the lakes increases, a flood fills the next bead down the string. But they do not know whether the flow of water which melts ice causes a chain reaction down the string.