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Topic Last Updated on 21-05-2024
Secrets of the Peaceful Continent
Antarctica was lucky: in 1959 in Washington, the 12 countries that had scientific missions on the continent signed an agreement to ban establishing military bases, conducting military maneuvers, and testing any kind of weapons on its territory. Since then, humans have gone there exclusively in the name of science. The results of the work of one such mission suggested that at a depth of several miles under the ice cap of Antarctica, the temperature is close to the melting point of ice. This assumption was expressed in 1957 and was the first step to a grand discovery.
Andrey Kapitsa
Another mission involved seismic soundings of ice in the area of the Soviet-operated Vostok Station (the word vostok means “east” in Russian), which was conducted by a scientific expedition led by Soviet geographer Andrey Kapitsa, son of Nobel laureate Pyotr Kapitsa. As a result, a signal was recorded, reflecting off a surface under the ice. For about 30 years, it served as evidence of the presence of a layer of frozen rock under an ice shell many miles deep. However, the reflecting plane was so smooth that even Andrey Kapitsa suggested that there must be a huge subglacial lake with a length of more than 155 mi, a width of over 30 mi, and a depth of more than half a mile!
It wasn’t until the 1990s that a technique was developed to confirm the existence of a body of water. The powerful radar and modern radio-locating method of geomagnetic deep sounding (GDS) enabled a British-Russian collective of scientists, led by Gordon Robin, to get results that even the most consummate of skeptics could not doubt: there is a giant lake under the layers of ice. Its contours appear on the icy surface of the continent. Jeff Ridley proved this in 1993 through the use of extremely precise satellite laser altimetry. It turns out that the Vostok Polar Station is in the center of an icy plain that is as flat as a table and can be considered a projection of the lake onto the surface.
The Vostok Station
The climatic conditions at the Russian Vostok station are probably the most severe on the planet. In July 1983, the lowest temperature on Earth was recorded there: –128.6°F (in such cold, eyeballs freeze almost instantaneously). The altitude of the station, 11,443 ft above sea level, causes a constant shortage of oxygen among polar explorers.
Living conditions at Vostok demand extensive adaptation, resulting in weight loss of up to 22–26 lbs. Since 1957, researchers have studied Antarctica’s climate, geology, and drilled into its ice. The nearby South Magnetic Pole is also a subject of study. Life around Vostok is scarce, with only trace amounts of microorganisms. The station hosts up to 50 people in summer but drops to 20 during winter.
Borehole 5G | Lake Vostok
The water in the lake has been completely isolated from the outside world for several million years. However, evolution continued there, and biological species appeared and went extinct. Life underwater “froze,” which, of course, means it is of great interest to researchers.
In 1990, the first thermal drills dug into the ice of Antarctica in the area of the Vostok station. The goal was to get to the lake and take samples of its unique water. It should be noted that Soviet scientific expeditions had been drilling into the ice of the southern continent since the 1970s — four of their wells were classified as being deep.
5G Well
Therefore, when the thermal borehole at Lake Vostok was drilled, the well was called “5G”, from the Russian piataia glubokaia, or “fifth deep well.” This was achieved through thermal boring, when ice is melted by the movement of a heated drill head. This required a huge amount of electricity — ten times more than with traditional mechanical drilling. For this reason, and also because of the poor quality of the ice patch selected, the researchers switched out the thermal drill for the electromechanical KEMS–132. This shift happened at a depth of 9,000 ft.
Why work stopped?
But in 1998, at the 11,886-ft mark, the work was stopped. Why? Drillers were using a mixture of aviation kerosene with a special weighting agent, freon, as drilling fluid. The weighting agent is necessary to fully compensate for the rock pressure of the ice mass: without it, the borehole may collapse into itself. Can you imagine what this poisonous mixture would do if it got into the lake? The majority of its unique biota would die as soon as the drill entered the water.
That is why, for the purpose of preserving the lake’s ecology, work was suspended for eight whole years, just a little under 500 ft away from the lake’s surface. This was on the initiative of SCAR, the Scientific Committee on Antarctic Research. Later, oligodimethylsiloxane silicone fluid compounds came along to help researchers and drillers. This hydrophobic liquid, due to its chemical inertness, is harmless to humans and animals, which means there is a good probability that its effect on the microorganisms of the lake is also neutral. Additionally, the mechanical drill was replaced with a thermal one.
Ice Cuttings from Different Borehole Depths
The ice shell on the surface is constantly forming as snow is compacted by new precipitation and becomes immersed in lower layers, where it has a granular structure and is located at a depth of up to 177 ft. Further on, it becomes denser — in the more recent snow, up to 6,027 ft, bands of annual snowfall are clearly visible. At the bottom of the borehole (10,009 ft), the ice has impurities of sand and silt. The lower the layer of ice, the more pressure it is under.
The TBPO-132 creates an additional buffer layer in thawing water under an organosilicon wash solution. The density of the liquid in the well had to be lowered, the pressure was 0.3–0.4 MPa, below the estimated pressure in Vostok. This way, the drilling mud would not enter the lake. The water had to independently travel 100–130 ft upwards in the borehole and instantly freeze. It was proposed that the “fresh” relict ice be obtained with the help of a mounted electromechanical drill.
The Uncovering
On November 28, 2011, a new drilling unit arrived at the Vostok Station to undertake its journey downwards. By January 12, 2012, the ice-borer reached a depth of 12,262 ft, and on February 4, at a depth of 12,355 ft, it came into contact with the surface of the water, thus ending the under-ice lake’s 15 million years of isolation.
Much of this complicated technical operation did not go as planned. In particular, it turned out that the water temperature in the lake was 27.23°, and that the pressure there exceeded 400 atm! Therefore, the water from Lake Vostok rose 2,000 ft through the borehole, mixing with the drilling fluid and freezing. About 8-10 gal of water mixed with water-polluting microorganisms was extracted from the surface. A year later, they managed to isolate a 6½-foot ice core and investigate its composition. However, ice in the hole complicated the re-drilling, so on January 15, 2015, scientists made a parallel well and re-entered the relict snow.
Sounding the Earth
Scientists create mini-earthquakes during exploration, directing shockwaves into the ground to study crustal structure. Seismic survey stations record reflected waves, aiding in locating oil, gas deposits, caves, and subterranean lakes at extreme depths.
Different methods
In the late 1950s, seismological studies in Antarctica revealed the ice sheet thickness, ranging from 1½–2½ mi. While effective, this method is energy-intensive and costly. A newer approach, geomagnetic deep sounding, uses radar pulses to measure crustal features. This method, employing airplane-mounted ground-penetrating radar, accurately measured the size of subglacial Lake Vostok.
No dissolved organic carbon was found in the ice, but it had high oxygen saturation, up to 0.11 oz per gallon, ten times the bacteria survival limit. Microbiologists spent time isolating contaminant bacteria from external sources, discovering rare species soon after.
New microorganism
In 2016, the Petersburg Nuclear Physics Institute discovered a new microorganism, temporarily named w123–10, with around 14% unique genome sequences. Similarly, in 2004, bacteria like Hydrogenophilus thermoluteolus were found thriving at –58° during drilling. Despite few findings, life persists wherever there’s water, hinting at more discoveries ahead.
Lake Vostok isn’t unique; Antarctica boasts over 400 smaller under-ice reservoirs. Lake Ellsworth, isolated for over 125,000 years, is now a key research target. US polar explorers collected water samples from Lake Whillans in 2013, revealing microbial colonies thriving on carbohydrates for energy, not sunlight.
Map of the Subglacial Lakes of Antarctica
Through the use of radar and satellites that penetrate through the icy depths, over 150 subglacial lakes have been discovered under the Antarctic ice sheet.
Decades of research on unique lakes have only scratched the surface of icy underwater relics, with limited success. Scientists propose that exploring deeper into these subglacial waters, especially closer to the lake bottom where temperatures are less extreme, could offer answers to many questions, including the potential for extraterrestrial life.
Take Saturn’s moon, Enceladus, for example. As we know it is covered with many miles of icy crust. Underneath, there could be a hidden ocean, full of life. And Enceladus is not unique: Jupiter’s moons, Ganymede, Callisto, and Europa are also presumably home to deep oceans. Lake Vostok can become a model for the development of extraterrestrial life. We won’t be able to land on the satellites of Saturn and Jupiter in the foreseeable future, but it is quite possible to penetrate the depths of a terrestrial subglacial lake.
Ancient Secrets: Lake Vostok Sediments Hold Clues to Antarctica’s Past
The extremely weak current in Lake Vostok implies that the floor sediments have stayed unchanged for millions of years. This is a very enticing opportunity for geologists, who could possibly determine the history of the whole continent based on this sediment alone. Its shape and composition can tell us about the climate and movement of Antarctica’s ice sheet. For now, geologists will keep studying the borehole that has already revealed information about the climate over the last 400,000 years!
This epic of the depths of Antarctica is a remarkable example of cooperation between the international scientific community, where relations between countries and individual people are not overshadowed by military operations or political sentiment. The Scientific Committee on Antarctic Research has become a roundtable where leading scientific powers share information and synthesize their knowledge on the challenging business of studying Antarctica. We continue to follow the quest of the “lost Vostok”— the future promises to surprise us!
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