New lakes found beneath Antarctic ice
and World Science staff
Scientists say they have discovered the second and third largest known of nearly 150 lakes locked under Antarctic ice.
The lakes, big enough to measurably weaken the Earth’s gravity in the area, may house exotic organisms adapted for extreme cold, they add.
The largest of these “subglacial lakes” worldwide is Lake Vostok, which lies under more than two miles of Antarctic ice. Scientists have identified more than 145 other lakes trapped under the ice, none of which have approached Vostok’s size or depth.
In the February issue of the journal Geophysical Research Letters, scientists from the Lamont-Doherty Earth Observatory of Columbia University, New York, describe the size, depth and origin of Vostok’s two largest neighbors.
One of these has been dubbed simply “90ºE,” marking its longitudinal position on the Earth. The other is named Sovetskaya after a Russian research station coincidentally built above it. The findings also indicate that, as suspected with Lake Vostok, an exotic ecosystem may still be thriving in the icy waters 35 million years after being sealed off from the surface, the researchers said.
Geophysicists Robin Bell and Michael Studinger pieced together the information using data from ice-penetrating radar, gravity surveys, satellite images, laser techniques, and from of a Soviet expedition that unknowingly crossed the lakes in 1958 and 1959.
The researchers reported that 90ºE covers 2,000 square kilometers, which is about the size of Rhode Island, and is second only to Lake Vostok’s 14,000 square kilometers. Sovetskaya Lake was calculated to be about 1,600 square kilometers. Both are sealed beneath more than two miles of ice.
The lake depths, estimated to be at least 900 meters, were calculated from gravity data taken during aerial surveys in 2000 and 2001. Because gravitational force is directly related to mass, a decrease in gravitational pull over the ice sheet corresponds to a decrease in mass beneath the ice. “Over the lakes, the pull of gravity is much weaker, so we know there must be a big hole down there,” said Bell.
Their depth, along with the fact that they are parallel to each other and Lake Vostok, indicate that the lakes are created by deep faults in the Earth’s crust, the researchers concluded.
Bell added that there are several reasons to think the lakes receive nutrient flows and undergo mixing of the water, both of which would help support life.
The scientists suspect that despite climate changes on the surface over the last 10 million to 35 million years, the the lakes have remained remarkably constant in size, providing a stable, if inhospitable, environment that may harbor an ancient and alien ecosystem. But just how, when or even whether scientists will risk the possibility of contaminating the lakes to confirm their suspicions remains the subject of an ongoing international debate.
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