Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Two new lakes found beneath Antarctic ice sheet

26.01.2006


Ancient water bodies may contain ecosystems adapted to life beneath more than two miles of ice



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 Review 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 90ºE 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.

Bell and Studinger, along with colleagues from the University of New Hampshire and NASA, report that the 90ºE 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.

The study was supported by the Lamont-Doherty Earth Observatory, the Palisades Geophysical Institute, NASA, and the National Science Foundation.

Ken Kostel | EurekAlert!
Further information:
http://www.ei.columbia.edu
http://www.earth.columbia.edu
http://www.ldeo.columbia.edu

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>