In the early 1990s, a Russian drilling rig encountered something peculiar two miles beneath the coldest and most desolate place on Earth. For decades, the workers at Vostok Research Station in Antarctica had been extracting core samples from deep scientific boreholes, and analyzing the lasagna-like layers of ice to study Earth's bygone climate. But after tunneling through 414,000 layers or so-- about two miles into the icecap-- the layers abruptly ended. The ice below that depth was relatively clear and featureless, a deviation the scientists were at a loss to explain. In search of answers, the men drilled on.
Unbeknownst to the Russians, their drill had mingled with the uppermost reaches of one of the largest freshwater lakes in the world; a pristine pocket of liquid whose ecosystem was separated from the rest of the Earth millions of years ago. As for what sort of organisms might lurk in that exotic environment today, no one can really be certain.
In prehistoric times the Antarctic continent was much more temperate, with lush tropical foliage and thriving wildlife. But millions of years ago the Earth's extra-flaky crust caused the landmasses of Australia and South America to gradually peel away from Antarctica, creating a ring of open sea around the southernmost continent. This allowed a massive oceanic current to begin encircling the pole, deflecting warmer northerly currents away from Antarctica's shores. Without warm water to moderate the temperature, a scab of polar ice developed over the formerly forested lands.
Roughly forty million years later, in 1996, the men and women of the Scientific Committee on Antarctic Research (SCAR) urged their Russian colleagues to halt their indiscriminate drilling.
Airborne radar and satellite altimetry had finally managed to penetrate the thick mound of ice over the south pole, and after electromagnetically groping every rock and crevice in Antarctica, a flat region 155 miles long and 31 miles wide was detected below Vostok Station. As improbable as it seemed, SCAR researchers surmised that a liquid lake must lie just below the Russians' steadily advancing bore shaft. In order to avoid contaminating the huge lake with surface bacteria and drilling chemicals, the tunneling had to be stopped.
Lake Vostok was found to have approximately the same surface area as the great Lake Ontario in North America, with more than thrice the depth. Separated from sunlight by two miles of solid ice, the subglacial lake is a place of profound darkness and bitter cold. The water temperature is estimated at 3 degrees below zero Celsius, but it maintains a liquid state due to the crushing weight of the polar ice slab; the temperature at which water freezes is significantly lower under such phenomenal pressure. It is also suspected that geothermal heat from the ground below adds some ambient warmth. According to the ice cores extracted by the Vostok Base scientists, the lonely lake has been sealed beneath the ice for at least 500,000 years, but possibly as much as 25 million.
As requested, the Russians temporarily suspended their drilling efforts pending further study. Their borehole-- which was filled with sixty tons of kerosene and freon to prevent re-freezing-- stopped within a mere 300 feet of the lake surface. The anomalous ice they had encountered turned out to be lake water which had long ago frozen to the bottom of the slowly migrating glacier. These ice samples provided a few insights into the lake's anatomy, such as its lack of salt, and its absurd overabundance of oxygen; under extreme pressures oxygen will more readily dissolve in water. If the drilling over Vostok had continued uninterrupted, thereby encroaching upon the liquid portion of the lake, the hapless Russians might have been assaulted by a towering geyser of ancient water and liberated oxygen due to the astonishing pressure of the hidden body of water.
In the wake of the lake's discovery, there arose considerable debate regarding the likelihood of finding life there. The environment is remarkably similar to the dark and cold ocean below the surface of Jupiter's ice moon Europa, so the discovery of life in Vostok could have interesting extraterrestrial implications. Due to the cold, the complete absence of sunlight, and the toxic levels of oxygen, many scientists are certain that Lake Vostok is sterile. That, however, would be a scientific first, since never before has a completely lifeless body of water been found on Earth. Extremophile organisms have turned up in the unlikeliest of places, including within volcanic vents on the ocean floor, in the rocks deep in the Earth's crust, and in frozen arctic soil.
It is not unreasonable to suggest that cold-tolerant creatures could thrive in the waters of Lake Vostok, overcoming the oxygen saturation with extraordinary natural antioxidants. But millions of years of evolutionary isolation in an extreme environment may have created some truly bizarre organisms. This notion is supported by the ice samples drawn from the ice just above Lake Vostok, where some unusual and unidentifiable microbial fossils have been found. But the possibility that they are merely contaminates has not yet been completely ruled out.
At present, a number of researchers are mulling over methods to investigate the lake's unique ecosystem without defiling its pristine nature. The introduction of any organisms or chemicals from the surface could irreversibly pollute its waters, and there is a small but real possibility that the lake's alien organisms could be dangerous to humans. To date, the best candidate seems to be the cryobot, a fittingly phallic penetrating probe designed to gingerly work its way into the virgin lake. Its heated tip would melt a channel straight into the ice as it unspools a power and communications line behind it. The melted water would quickly re-freeze behind the cryobot in temperatures which linger around minus 100 degrees Fahrenheit, and once it finally reached the water it would eject a small submersible hydrobot to capture images and take measurements.
Though most scientists are proceeding with considerable caution, and some advocate avoiding the lake altogether, there are reports that the Russian researchers intend to restart drilling in order to reach the lake before their rivals. The Antarctic Treaty of 1961 guarantees all nations the right to conduct non-military scientific study on the continent, therefore little can be done to intervene if the men at Vostok station insist upon proceeding. Several smaller lakes have since been identified beneath the Antarctic icecap, but geologists speculate many of these are linked by a network of under-ice rivers, so contaminating just one lake might taint them all beyond repair.
If science seizes the opportunity to properly explore this perplexing pocket of liquid, it would be equally enlightening whether there is a plethora of life or a complete absence thereof. If the lake is found to be sterile, its desolate waters will provide some measure of insight into life's practical limitations. But if living things do indeed lurk beneath the thick Antarctic icecap-- even if only in microbial form-- their presence will demonstrate that life is made up of truly resilient stuff, with scientific implications well beyond the scope of our planet.
Update 06 February 2012: The Russians seem to have penetrated the ice and reached the upper reaches of the subglacial lake. Further penetration is on hold due to international outcry for more precautions.
07 March 2013: "Russian scientists believe they have found a wholly new type of bacteria in the mysterious subglacial Lake Vostok in Antarctica, the RIA Novosti news agency reported on Thursday. The samples obtained from the underground lake in May 2012 contained a bacteria which bore no resemblance to existing types, said Sergei Bulat of the genetics laboratory at the Saint Petersburg Institute of Nuclear Physics."
07 July 2013: "Analysis of ice cores obtained from the basin of Lake Vostok, the subglacial lake that Russian scientists drilled down to in 2012, have revealed DNA from an estimated 3,507 organisms. More info."