Everything about Lake Vostok totally explained
Lake Vostok ("east") is the largest of more than 140
subglacial lakes found under the surface of
Earth's southern-most
continent —
Antarctica. It is located at, beneath
Russia's
Vostok Station, 4,000
meters (13,000
feet) under the surface of the central Antarctic
ice sheet. It is 250 km long by 50 km wide at its widest point, thus similar in size to
Lake Ontario, and is divided into two deep basins by a ridge. The water over the ridge is about 200 m (650 feet) deep, compared to roughly 400 m (1,300 feet) deep in the northern basin and 800 m (2,600 feet) deep in the southern. Lake Vostok covers an area of 15,690 km² (6,058 mi²). It has an estimated volume of 5,400 km³ (1,300 cubic miles) and consists of
fresh water. The average depth is 344 m. In May 2005 an island was found in the center of the lake.
Discovery
Radar imaging
Russian and
British scientists discovered the lake's existence in 1996 by integrating a variety of data, including airborne ice-penetrating
radar imaging observations and spaceborne radar
altimetry. It has been confirmed that the lake contains plenty of liquid water under the more than three-kilometer thick
icecap, promising to be the most unspoiled lake on Earth. Its water is very old, with a mean
residence time in the order of one
million years (as compared with six years for
Lake Ontario, which is typical for lakes of that size). above the suspected boundary where the ice sheet and the liquid waters of the lake are thought to meet to prevent contamination of the lake from the 60 ton column of
freon and aviation fuel the Russians filled it with to prevent it from freezing over.
From this core, specifically from ice that's thought to have formed from lake water freezing onto the base of the ice sheet, evidence has been found, in the form of microbes, to suggest that the lake water supports life. Scientists suggested that the lake could possess a unique habitat for ancient bacteria with an isolated microbial
gene pool containing characteristics developed perhaps 500,000 years ago.
Environment
Ecosystems
Since it has been discovered that Lake Vostok consists of two separate basins divided by a ridge, it has been suggested that the chemical and biological compositions of these two
ecosystems are likely to be different.
Pressure and Oxygen
Lake Vostok is an
oligotrophic extreme environment, one that's
supersaturated with
oxygen, with oxygen levels 50 times higher than those typically found in ordinary
freshwater lakes on Earth. The sheer weight of the continental icecap sitting on top of Lake Vostok is believed to contribute to the high oxygen concentration. Besides dissolving in the water, oxygen and other
gases are trapped in a type of structure called a
clathrate. In clathrate structures, gases are enclosed in an icy cage and look like packed snow. These structures form at the high-pressure depths of Lake Vostok and would become unstable if brought to the surface.
Due to this high-pressure extreme environment, if water were to be released from Lake Vostok (from drilling, for example), it could gush like a popped
carbonated drink can and, if not contained, open the lake to possible contamination and pose a potential hazard to scientists.
Life
No other natural lake environment on Earth has this much oxygen. Any organisms in Lake Vostok must be capable of overcoming very high oxygen stress. Some have speculated that such organisms may have had to evolve special adaptations, such as high concentrations of protective
enzymes, in order to survive the lake's oxygen-rich environment.
Due to the lake's similarity to a moon of
Jupiter,
Europa, confirmation that life can exist in Lake Vostok might strengthen the argument for the presence of life on Europa.
Tidal forces
In April 2005,
German,
Russian, and
Japanese
researchers found that the lake has
tides. Depending on the position of the
Sun and the
Moon, the surface of the lake rises between 1 and 2 cm. The researchers assume that the fluctuation of the lake surface has the effect of a pump that keeps the water circulating, which would be necessary for the survival of
microorganisms if there are any.
Research
To probe, without contamination, the waters of Lake Vostok for life, plans were initiated in
2001 by the
Jet Propulsion Laboratory to start with a melter probe — the so-called "
cryobot" — which melts down through the ice over Lake Vostok, unspooling a communications and power cable as it goes. The cryobot carries with it a small submersible, called a "hydrobot", which is deployed when the cryobot has melted to the ice-water interface. The hydrobot then swims off and "looks for life" with a camera and other instruments.
In January 2006, Robin Bell and Michael Studinger, Geophysical researchers from
Columbia University, announced in
Geophysical Research Letters the discovery of two smaller lakes under the icecap, named
90 Degrees East and
Sovetskaya.
It is also suspected that the Antarctic
subglacial lakes may be connected by a network of
subterranean rivers. Glaciologists Duncan Wingham (
University College,
London) and Martin Siegert (
University of Bristol, now
University of Edinburgh) published in
Nature in 2006 that many of the subglacial lakes of Antarctica are at least temporarily interconnected. Obviously because of varying water pressure in individual lakes, large, sub-surface rivers may suddenly form and then force large amounts of water through the solid ice.
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