Lake Vostok, located in the immediate vicinity of the South Geomagnetic Pole of the Earth, is perhaps one of the last serious mysteries of our world. The water in the lake, taken in ice captivity for 20 to 14 million years! back, saved an informational "snapshot" of the prehistoric state of the planet Earth. And this means that people have the opportunity to look into such a distant past, which they did not dare to dream of. For example, by the state of the water it will be possible to judge the composition of the ancient atmosphere, volcanic processes that shook the planet at the beginning of the Quaternary period. And even about the most ancient forms of life.
To date, 45 states have their stations in Antarctica and carry out active scientific work. And the Russians have the palm in the discovery of the subglacial "relic", namely the flag navigator of the aviation detachment of the 4th Soviet Antarctic Expedition R. V. Robinson. He, like other pilots who later flew from Mirny station to the region of Vostok station, saw very large areas of the surface, which sharply differed from the rest and were conventionally called "lakes".
They always met in the same places, so they were even used for navigation. But then no one took it seriously. The same fate awaited the hypothesis of the famous glaciologist I. A. Zotnikov (now Corresponding Member of the Russian Academy of Sciences, Doctor of Geographical Sciences), who suggested the possibility of melting of the thickness of the Antarctic glacier during its movement.
It would seem, what kind of lake can we talk about when the average temperature in Antarctica reaches -57 ° C. Water freezes at this temperature without a doubt. However, the fact of the matter is that the lake is not located on the surface, but under a 4-kilometer layer of ice. To tell the truth, even when these flat plains were discovered by the pilots, they called them lakes for a surface that resembles a lake from a height. It so happened that it was over such a lake, without knowing it, that in 1957 the participants of the Soviet polar expedition set up the Vostok station (the lake was given the same name in 1993).
Even A. Kapitsa, then a novice geographer, and later an academician, having received a non-standard reflected signal during seismic sounding in 1959 and 1964, did not dare to make such a bold guess. The signal gave two reflection peaks instead of one - at 3730 and 4130 m. From this it turned out that the glacier strata extended to a depth of 3730 m, and the bedrock rocks of Antarctica began at a depth of 4130 m. Scientists then explained the mysterious form of the signal by sedimentary rocks lying under the ice.
Now they have found out for sure that seismic waves "stumbled" not on sedimentary deposits, but on a 400-meter water column. And in the 1970s, the Scottish British Polar Institute carried out a large program of air flights with radio waves sounding the glaciers of Central Antarctica. On the radio sounding tapes, the routes in some places crossed the areas where reflections under the ice had a rather peculiar character. It was possible to make an assumption that it was at these points that the flight lines crossed large accumulations of subglacial waters, which then, in the 1970s, were called subglacial lakes. And the lake, above which the Vostok station was located, was named after her. But all this was still just a scientific hypothesis.
And only at the beginning of the 1990s, when scientists obtained laser altimetry data obtained from the ERS-1 space satellite, it became obvious: in the Vostok station area there is a large flat plain up to 280 km long and up to 70 km wide. These data forced A. Kapitsa to raise the results of his long-standing seismic sounding. Having collected all the available scientific research, the academician made a report that became a real world sensation. So in 1994, the world learned that inside the lifeless pole of cold there is an ancient conserved lake. The discovery of a giant subglacial lake in Antarctica near the Russian Vostok station is rightly ranked among the largest geographical discoveries of the 20th century.
The size of the lake was impressive: it is more than 280 km long and 50 km wide. Thus, the area of the water surface is more than 10,000 km? and is comparable only with such lakes as Onega (Europe), Chad and Rudolph (Africa), Nicaragua (Central America) and Titicaca (South America). The average depth in the lake is 750 meters. After that, Soviet specialists from the polar marine geological exploration expedition thoroughly "probed" the lake using the method of ground sounding.
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Over the years, thousands of continuous seismic sections have been carried out in various directions of the lake. The results were stunning: for the first time a man "saw" what was hidden from him under a 4-kilometer thick layer of ice. For example, they found out that on the western part of Lake Vostok there are many bays, bays, peninsulas. It is shallow, in contrast to the eastern one, which has a steep deep-water coastal edge.
The bottom of this freshwater basin curved with a crescent has a sharply rugged relief, the depth in some places reaches 1200 m. Thermal scanning of the surface showed that the water temperature in the lake is quite high - approximately from + 10 ° to + 18 ° C. And recent studies by Japanese and American scientists show that the lake is divided by a reef into two independent areas, each of which may have its own unique microbiological environment.
Now 77 lakes have been discovered under the ice shell of Antarctica. But the largest of them is Lake Vostok. And its uniqueness lies in the fact that the lake waters were completely cut off from direct contacts with the atmosphere, with the sun, winds and life on the surface for several million years by the thickness of ice. This means that the biological and chemical composition of water throughout this time remained unchanged. Many of the researchers believe that unique life forms can inhabit the ancient water. Lake Vostok differs in the force of gravity: the researchers were convinced that gravity is weaker over deep-water bodies of water, because the density of water is half the density of a stone.
Flying around the lake by plane, scientists have compiled a map of its bottom. Their work showed that the lake contains about 5.4 thousand cubic kilometers of water - approximately 5% of the world's total freshwater supply. It was also suggested that Lake Vostok is located in a rift fault in the earth's crust. Then, it is likely that processes close to volcanic ones occur at its bottom, with the eruption of salt flows. Therefore, in the bottom layers, the water can be salty. And from above, due to the melting of the glacier, the water is most likely fresh.
The data obtained also made it possible for scientists to determine the height (level) of the free surface of the water. It turned out that it is 3100 m above sea level, that is, the water of Lake Vostok does not have direct contact with the ocean that surrounds Antarctica on all sides. In addition, above the water surface there is a domed vault of hundreds of meters high, filled with ancient air.
Why are glaciers melting at such a low temperature? The scientific answer for the untrained person can explain little. But in short it looks like this. Following the Russian glaciologist I. Zotnikov, scientists from the University of Bristol carried out in 2000 a threefold radar survey of the lake.
It turned out that near its western and northern outskirts, despite the low temperatures, almost 10 centimeter layer of ice melts every year (the melting temperature is lower than usual due to the high pressure of the ice sheet lying on top!). It's even simpler - the ice cap acts as a thermos, and the heat of the Earth melts the ice. Subsequently, the melt water freezes again at the base of the ice cover, increasing it from below, but already at the opposite shores. Thus, the waters of Lake Vostok are slowly circulating and the full cycle of their renewal, according to researchers' estimates, takes 15-30,000 years.
Back in the early 70s of the last century, when there were only guesses about the existence of the lake, a project for deep ice drilling began at Vostok station. Initially, the main purpose of deep drilling was to obtain a continuous ice core - a cylindrical column of ice - a kind of glacier slice, the study of which made it possible to reconstruct all climate changes on our planet over the past 420,000 years, recorded in layers of accumulated ice.
Back in 1959, the head of the Vostok station, VS Ignatov, was able to reach a 40-meter depth with the help of a thermal drill. A year later, the thermal drill, designed by I. A. Zotikov, went 10 meters more. Due to imperfect technology, it was not possible to achieve more impressive results then - the drill simply froze into the ice. The situation changed with the arrival of specialists from the Leningrad Mining Institute in 1967, who had been drilling ice for three decades at the Vostok station, having managed to go deep into the ice strata to 3623 m.
Scientists have obtained accurate data on changes in climate over the past 420,000 years. Thus, we received information about four complete climatic cycles on Earth. But it was this well that became the subject of discussion. When Russian researchers began to deepen the well, they found out that ice of non-atmospheric origin, according to isotopic analysis, was below a depth of 3543 m. As Valery Lukin said, atmospheric ice is formed as a result of snow falling, which, under its own weight, turns into firn, and later into ice. But the ice from the well was clearly formed as a result of water freezing.
Based on this, the aforementioned Igor Zotikov proposed a new theory. Based on the hypothesis of the existence of the supercontinent Gondwana (it included Africa, South America, Asia, Australia and, possibly, Antarctica, which, subsequently split, began to drift around the globe and subsequently took up the present position), he suggested that Lake Vostok appeared just before the glaciation of Antarctica, which began after the continent slipped to the cold pole. The waters of the newly formed lake were covered with ice along with the entire continent. According to Russian researchers, the thickness of the lake ice above the water is 210 m. Academician Zotikov suggested that this is the very equilibrium value through which a cold wave cannot penetrate for 50 million years.
1994 - Russian glaciologists drilled three-quarters of the way to the lake, studying the 400-thousand-year climatic history of the Earth, recorded in layers of growing ice. Samples taken very close to the "dome" show the presence of microbes (including those previously unknown to science), nutrients and various gases, including methane. In other words, all the typical signs of biological processes have been found now, perhaps, occurring in a completely isolated ecosystem. That is, it is a unique "capsule from the ancient world", opening which, scientists will be able to solve many of the most complex unsolved problems in the history of the Earth.
The Russian record for superdeep drilling has not yet been broken: the Russians were able to reach the prohibitive mark of 3623 m (specialists from other countries have not yet overcome the barrier of 2500). Nevertheless, the samples of ice extracted in 1998 from this depth were divided equally by scientists from Russia, America and France. Having reached this point, the studies were established. Russian equipment could have advanced further, but drilling was stopped due to the danger of non-sterile sampling, which could damage the unique relict system of the lake. Indeed, in a natural niche isolated for hundreds of thousands of years, its own biological balance has developed.
What can happen when the atmospheric air saturated with modern microflora rushes in with the boers? Would an unexpected expansion lead to irreparable consequences? And some of the countries even urge not to invade the unknown. What if from there, out of the age-old darkness, some "plague of the XXI century" emerges?
For a number of physical reasons, there is an assumption that Lake Vostok is oversaturated with gases (in particular, oxygen), and microorganisms that have adapted to these conditions may have unique properties. A careless collision of two worlds can lead to a conflict, and it is not known who can emerge from it as a winner: the microbes of Lake Vostok can suffer from the invasion of microorganisms from the earth's biosphere, but we, theoretically, can also be in the role of a victim.
Therefore, in 1998 at a meeting of SCAR - the International Scientific Committee for Antarctic Research - it was decided to stop drilling. “The lake is very valuable to experiment with,” warns Keenan Ellis-Evans, a microbiologist based in Cambridge, UK.
However, even being completely unsolved, Lake Vostok has already presented science with a lot of invaluable information. For example, his proposed model struck astronomers with a similarity to the natural conditions of Mars. It is known that the north pole of the red planet is also covered by a giant glacier. And millions of years ago Mars, like the Earth, experienced sharp changes in the tilt of the axis of rotation. In other words, the areas that are now the poles of cold, on both planets had a much warmer climate in the past.
Then the hypothesis that our space neighbor also has polar lakes similar to Lake Vostok becomes quite plausible. And if life is found under the glaciers of Antarctica, then why not be found on Mars? Even the US National Space Agency is seriously interested in the problem of the Earth's lake, comparing it with the ocean of Europa, the moon of Jupiter.
It turns out that the subglacial lake on Earth is an ideal testing ground for testing the technology of penetrating under the ice in Europe, where the ocean is at least covered with a 20-kilometer layer of ice, and Lake Vostok is “only” 4 kilometers long. But the problems remain the same. How not to bring "dirt" (terrestrial bacteria) to the Jupiterian moon, how to break through the ice, how to ensure the transmission of a signal from the underwater vehicle to the surface?
The Antarctic core made it possible to judge the global climate changes that have occurred on the planet over the past hundreds of thousands of years. According to the ratio of oxygen isotopes in air bubbles, scientists have determined the change in the content of carbon dioxide in the atmosphere over the past half a million years. It is already reliably known that it has changed - and very much. And most importantly - without any human participation! But it is precisely the "greenhouse effect" caused by the development of human civilization that proponents of global warming explain the increase in average atmospheric temperatures. Studies have shown that volcanic activity or, say, giant forest fires, emitted much more carbon monoxide into the atmosphere.
Further more. According to Academician A. Kapitsa, at first the temperature of the atmosphere rose, and then the content of carbon dioxide in it increased, and not vice versa! In a word, they are already making amazing discoveries! Traces of DNA were found in a core of Antarctic ice taken from a depth of 3543 m. “The researchers immediately realized that they were dealing with a unique natural 'relic,' said V. Lukin, head of the Russian expedition of the Institute of the Arctic and Antarctic.“It is possible that the lake harbors bacterial life forms unknown to modern science, which are about half a million years old. The found DNA, which does not coincide with terrestrial organisms, is a confirmation of this. Specialists in molecular biology are also convinced that this kind of DNA is not in the catalogs of world science."
Research is in full swing and brings new discoveries. In a core of lake ice from a well, molecular biologists from the St. Petersburg Institute of Nuclear Physics discovered three types of thermophilic dead bacteria, unknown to science. Their modern counterparts develop in hydrothermal springs in active regions of oceans and continents at temperatures of + 40–60 ° C. It follows from this that once the waters of Lake Vostok were warmer than all modern southern seas.
The Russian microbiologist S. Abyzov, as a result of core studies from the deepest borehole in Antarctica, proved that microorganisms exist in a state of suspended animation in ice up to the deepest horizons. So far, it is believed that life that can be found in lake water or its bottom sediments is also limited by microorganisms. At the same time, none of those that are known today could exist long enough in this water.
According to V. Lukin, this event, in terms of its scientific significance, can only be compared with the landing of a man on the moon. About 130 meters are left to the surface of the lake. “We expect to cover this distance in three winter quarters,” V. Lukin said.
The water layer of the lake separates only 130 meters of ice from the bottom of the well. What is waiting for humanity behind this small bridge?
V. Syadro, T. Iovleva