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Antarctic Lakes
Fri Jun 25, 2004
Listen in RealAudio 
The Antarctic interior, the coldest place on Earth, experiences only brief periods each
year with temperatures above freezing. Yet beneath miles of ice, scientists have
discovered liquid fresh water lakes. Hi, I’m Bryan Yeaton for The Weather Notebook.
At least 70 unfrozen lakes lie below the continental icecap. The largest, Lake Vostok, is
1,300 feet deep and covers an area equivalent to Lake Ontario. And, it lies 12,000 feet
below the Antarctic surface.
How can a lake survive two miles under ice at the coldest place on Earth, where
temperatures have plummeted to -129F?
First, ice is a good insulator, thus the cap’s bottom ice is warmer than the upper
surface. Under the pressure of two miles of ice, ice’s melting point falls to about 25
degrees, rather than the usual 32 degrees.
Also, the icecap’s weight causes it to slowly creep toward the ocean, and that creates
heat through friction as ice rubs against the underlying bedrock. Finally, geothermal
heat from Earth’s interior continually flows toward the ice-rock interface, enough to melt
some bottom ice, but not enough to significantly impact the icecap’s thickness.
Lake Vostok has been probed using NASA’s ice-penetrating radar. The lake is
believed to have been isolated from the surface for perhaps 15 million years and its
dark waters may contain unique microbial life.
Researchers started drilling slowly through the ice to learn Vostok’s mysteries in 1998,
but halted about 500 feet short of the liquid water to avoid any contamination. Some
believe the waters could fizz like a pop can when the pressure is relieved. Drilling will
extend another 150 feet this year while scientists debate how the final penetration
should best proceed.
Thanks to our contributing writer, meteorologist Keith Heidorn. The Weather Notebook
receives support from the National Science Foundation, and Subaru: Driven By What’s
Inside.
Today's Links
Lake Vostok:
http://www.ldeo.columbia.edu/~mstuding/vostok.html
A Great Under-Ice Lake in Antarctica:
http://www.earthinstitute.columbia.edu/news/story3_2_01.html
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