An intricate network of channels beneath Antarctica's ice sheets could allow water, and possibly life, to shuttle from one underground lake to another, a new study suggests.
Using ultra-precise radar measurements taken with the European Space Agency's ERS-2 satellite, researchers discovered small changes in the heights of surface ice overlying subglacial lakes in a region of the East Antarctic Ice Sheet known as Dome Concordia.
As one region lowered by about 10 feet, two others, located some 180 miles away, rose by about 3 feet.
The researchers believe this teeter-totter effect can be explained by the transfer of nearly half a cubic mile of water from one lake to two subglacial lakes over a 16-month period.
At its peak, this flow would have been equal to the water contained in nearly half a million 10-foot-deep Olympic-sized swimming pools.
The finding is detailed in the March 20 issue of the journal Nature.
Like beads on a string
"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 study leader Duncan Wingham from University College London.
Usually, there is little flow along the string. Over time, however, a buildup of pressure in one lake could send water flowing along the string, where it dumps into the next lake.
Once this process is set in motion, it triggers a positive feedback loop where flowing water melts the ice and carves out larger channels, allowing more water to flow.
Some of these discharges might even carry lake water all the way to the coast of Antarctica, where it gets dumped into the ocean, the researchers speculate. Such discharges could explain strange landscape features in East and West Antarctica that appear to have been sculpted by flowing water.
Contamination could spread
The new finding challenges a widely held notion that subglacial lakes formed in isolation and are long-lived.
It could also put a damper on planned drillings into Antarctica's largest subglacial Lake Vostok, to probe for signs of microbial life.
If subglacial lakes are interconnected, as the new finding suggests, then any type of contamination introduced into one lake could spread to others.
"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," Wingham said. "We had thought of these lakes as isolated biological laboratories. Now we are going to have to think again."