Two new lakes found beneath Antarctic ice sheet

January 26, 2006
Two new lakes found beneath Antarctic ice sheet 1
Figure 1: MODIS satellite image showing location of Sovetskaya Antarctic research station and 90╨E Lake in relation to Lake Vostok. Detail of area in the white box is shown in Figure 2.

The Earth Institute at Columbia University--Lying beneath more than two miles of Antarctic ice, Lake Vostok may be the best-known and largest subglacial lake in the world, but it is not alone down there. Scientists have identified more than 145 other lakes trapped under the ice. Until now, however, none have approached Vostok's size or depth.

In the February 2006 issue of Geophysical Research Letters, scientists from the Lamont-Doherty Earth Observatory, a member of The Earth Institute at Columbia University, describe for the first time the size, depth and origin of Vostok's two largest neighbors. The two ice-bound lakes are referred to as 90╨E and Sovetskaya for the longitude of one and the Russian research station coincidentally built above the other. The scientists' 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.

Geophysicists Robin Bell and Michael Studinger of Lamont-Doherty combined data from ice-penetrating radar, gravity surveys, satellite images, laser altimetry and records of a Soviet Antarctic Expedition that unknowingly traversed the lakes in 1958-1959. The shorelines of the lakes appeared in satellite images of the region as perturbations in the surface of the East Antarctic ice sheet. In addition, because the ice is effectively floating on the surface of the lakes, the ice sheet exhibits slight depressions over the lakes that appear in radar and laser elevations.

Two new lakes found beneath Antarctic ice sheet 2
Figure 2: Detail of ice surface revealing outline of 90╨E lake (center) and part of Sovetskaya Lake (beneath Sovetskaya research station). Data from 1958 Soviet study (colored dots) revealed a noticeable drop in the Earth's gravitational pull above the two lakes. White triangles mark the locations of smaller lakes beneath the ice.

Bell and Studinger, along with colleagues from the University of New Hampshire and NASA, report that the 90╨E Lake has a surface area of 2,000km2, which is about the size of Rhode Island, and is second only to Lake Vostok's 14,000km2 surface area. Sovetskaya Lake was calculated to be about 1,600 km2. 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 lake system is tectonic in origin, the authors conclude.

Shallow lakes scooped out by glaciers or a meteorite impact can quickly fill with sediment, and thus are short lived. Lakes created by faulted blocks of the Earth's crust, however, are deeper and don't fill in as rapidly. Many of the smaller sub-glacial lakes scientists have identified so far are believed to be shallow "ephemeral" lakes that were suddenly sealed off by the ice.

The combination of heat from below and a thick layer of insulating ice above keeps the water temperature at the top of 90ºE and Sovetskaya at a balmy √2 degrees Celsius, despite temperatures on the surface that can drop to √80 degrees Celsius in winter. Since the lakes are bounded by faults, Bell said it is likely the lakes receive flows of nutrients that could support unique ecosystems. Moreover, laser mapping of the ice sheet surface by NASA's Ice Cloud and Land Elevation Satellite (ICESat) revealed that this water-ice boundary, or ceiling, is tilted.

"Since the surface is tilted, we know that the ice sheet changes thickness over the lake and that will drive circulation in the lake," said Bell. "This will provide mixing and distribute whatever nutrients are in the lake, which is an important component of subglacial ecosystems."

This, along with the tectonic origin of the lakes, supports the idea that despite climate changes on the surface over the last 10 million to 35 million years, the volume of the lakes have remained remarkably constant, providing a stable, if inhospitable, environment that may harbor an ancient and alien ecosystem adapted to life beneath the ice sheet. However, 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.

Source: The Earth Institute at Columbia University

Explore further: Mystery at misfits flat

Related Stories

Mystery at misfits flat

July 29, 2015

An amateur has discovered a trove of meteorites on Misfits Flat dry lake in Nevada. No meteorites had been found at this tiny lakebed before. In an unusual twist, at least some of those turn out to have fallen less than 300 ...

New technology aids recovery of Alaska plane wreck

July 22, 2015

On Alaska's Mount Gannett, pleasant weather can turn nasty quickly. Sunshine gives way to frigid rain; clear skies fall victim to thick storm clouds and fog. Not ideal conditions for exploring a 63-year-old plane wreck on ...

Recommended for you

Earth flyby of 'space peanut' captured in new video

July 31, 2015

NASA scientists have used two giant, Earth-based radio telescopes to bounce radar signals off a passing asteroid and produce images of the peanut-shaped body as it approached close to Earth this past weekend.

Image: Hubble sees a dying star's final moments

July 31, 2015

A dying star's final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star's demise is still quite ...

How bees naturally vaccinate their babies

July 31, 2015

When it comes to vaccinating their babies, bees don't have a choice—they naturally immunize their offspring against specific diseases found in their environments. And now for the first time, scientists have discovered how ...

Exoplanets 20/20: Looking back to the future

July 31, 2015

Geoff Marcy remembers the hair standing up on the back of his neck. Paul Butler remembers being dead tired. The two men had just made history: the first confirmation of a planet orbiting another star.

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.