One of the world's largest lakes is located in Antarctica. But you cannot see it: it is sealed from above with four kilometers of ice. This is Lake Vostok, discovered by Soviet and Russian scientists. By studying a non-freezing freshwater reservoir isolated from the outside world millions of years ago, scientists hope to learn how life began on Earth and other planets.
Exactly 60 years ago, on December 16, 1957, Soviet polar explorers founded the Vostok research station in the coldest and most remote region of Antarctica. It is located near the South Magnetic Pole of the Earth at an altitude of 3.4 kilometers above sea level. Through this station, our geophysicists made seismic profiles to find out what is under the ice. Among them was Andrei Kapitsa - the brother of the famous host of the program "Obvious - Incredible" Sergei Kapitsa. Based on the data obtained, he assumed that in the station area under the glacier there is a layer of water.
The contour of Lake Vostok is visible on the surface of the glacier / NASA.
Smooth depressions on the ice surface were noticed by Soviet pilots, who surveyed areas of Antarctica that were completely inaccessible to people at that time. They called them lakes and used them for navigation. As it turned out later, these are indeed projections of lakes on the surface of the glacier.
For a long time, scientists thought that under the ice there were small and scattered areas of water. Only almost forty years after the first geophysical research, in 1994, Andrei Kapitsa announced the discovery of a giant lake in Antarctica, comparable in size to Ladoga.
Danger of infection
By this time, borehole 5G was already in operation at Vostok station. While laying it, the polar explorers, of course, did not know that under their feet was the last "blank spot" on the planet. They wanted to get ice from different depths and reconstruct the climate of past eras using the gas and solid inclusions contained in it. The well was filled with a mixture of kerosene and freon, which did not freeze and allowed to keep the rock pressure. Freon, by that time, was recognized as hazardous to the atmosphere and banned under the Kyoto Protocol. On this basis, and also for fear of contamination of the lake with chemicals and microorganisms from the surface, the international scientific community forbade Russia to drill further and recommended to develop a cleaner method. Well 5G was mothballed in February 1998, when about 130 meters of ice remained to the lake.
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It took eight years to refine the technology and prove that the drill and drilling fluid would never end up in the lake, and samples would be taken strictly inside the well.
Lake Vostok in Antarctica / Photo: FGBU “ AARI ”.
An autopsy revealed
During the forced downtime, Russian scientists found out almost everything about Lake Vostok that remote sensing methods allowed. It is separated from the surface by 3.7 kilometers of ice. The water bowl is elongated for 290 km and is divided into two parts. The southern one is smaller, but deep: about 800-1000 meters. The northern part, large and shallow, has a depth of 300 meters. Geophysicists have recreated the relief of the lake pit and found that it is confined to a fairly young fault in the earth's crust.
Drilling was resumed in winter 2006. The drill bit broke off twice, and when it was not possible to get it, the well had to be started obliquely from the place of the break in order to bypass the problem area. The surface of the lake was reached on February 5, 2012 at a depth of 3769.3 meters.
The second time the reservoir was opened on January 15, 2015. The samples taken from the lake were carefully examined, including for the presence of living organisms. The interest of scientists is understandable. “The main goal of entering the lake is to search for an unusual form of microbial life that can live in extreme conditions at pressures up to 400 bar and temperatures close to freezing point, without light, without organic carbon dissolved in water, with highly diluted ions of basic substances, long-term isolation from surface biota for at least 14 million years and, probably, with an excess of dissolved oxygen,”writes in an article based on the results of the study, head of work Sergei Bulat, head of the cryoastrobiology laboratory at the St. Petersburg Institute of Nuclear Physics. B. P. Konstantinov.
After cleaning the samples, 49 DNAs of different phylotypes of bacteria were identified in them, most of which, as it turned out, were superficial, and only two interested scientists. One type of DNA is similar to the aquatic bacterium Janthinobacterium sp., The other belongs to an unknown species and has less than 86% similarity with known microorganisms.
Is there life on Mars
Biologists have not yet drawn any conclusions from these findings. In fact, it is not even clear yet whether the lake is inhabited. The real breakthrough will come when water samples are taken from the bottom, where it is warmer and saturated with mineral nutrients. It is also advisable to take samples of bottom sediments, where, presumably, hot springs flow. Lake ice, frozen at the bottom of the glacier, told scientists about their existence. It found crystals of minerals that are formed in hydrothermal waters. But such a breakthrough will not happen before the technology of "clean drilling" is invented, which allows getting uncontaminated water. That is why the participants of the Russian Antarctic Expedition come to the Vostok station every year to try to solve this most difficult problem in real conditions.
Scientists believe that Lake Vostok existed before the icing of the mainland, which means that the descendants of ancient organisms that lived there before isolation can be preserved in it. The object is also interesting from the point of view of cosmology, as it represents a model of a reservoir on other planets and their satellites, where life could arise under the ice.
How many secrets Lake Vostok hides - time will show, but it is already obvious what great scientific and social significance this unique object, to which we have made our way through, kilometers of ice, has for the whole world, and how important it is to keep it clean.
Tatiana Pichugina