Ice-encased Lake Vostok a scientific jewel

Question: How can a lake the size of Lake Ontario go unreported until 1996? The lake in question is 124 miles long, more than 30 miles wide, 1,500 feet deep and is listed by Richard Monastersky in the June 29, 1996, issue of Science News as covering an area of more than 5,400 square miles.

The answer is the fact that Lake Vostok lies buried under nearly 21/2miles of glacier ice. The lake is located in the interior of the Antarctic continent directly beneath the Russian Vostok Research Station. As several recent articles attest, it is drawing a great deal of attention from geologists, climatologists, biologists and even NASA.

According to Martin Siegert in the November-December issue of American Scientist, Lake Vostok was nearly discovered several times in the past. In 1961, a Soviet military pilot reported spotting a huge flat area on the Antarctic ice sheet that he described as a lake. What he saw was a surface feature of a glacier that is moving over water, but the report was ignored. Seismic data taken by Andrei Kapitsa of Moscow State University in 1964 to measure the depth of the ice sheet beneath the Vostok Station also revealed subterranean water but, as the lake’s presence was not suspected, it went unnoticed and the roll of seismic paper was stored away for the next 30 years. It was not until 1973 that airborne radar spotted Lake Vostok, along with several smaller water bodies beneath the glacier, and another 20 years passed before the European Remote Sensing Satellite mapped Lake Vostok in 1993. Kapitsa then dug out his 30-year-old records and found that his seismic readings confirmed the data from the satellite. Because of his earlier, although unnoticed, discovery of the lake, Kapitsa was made lead author on the formal announcement of Lake Vostok’s discovery in the June 20, 1996, issue of Nature.

Lake Vostok is considered a research gem because it contains water that has been sealed away from the rest of the world for a low of one million years according John Priscu et al in the Dec. 10, 1999, issue of Science and up to 15 million years by Siegert. Because of its isolation, writes Monastersky in the Oct. 2, 1999, issue of Science News, the lake provides an unparalleled opportunity to study ancient microorganisms that may exist in its waters, examine bottom sediments that could yield clues to climate changes over tens of millions of years, and to analyze atmospheric gases and organic matter trapped both in the water and the sediments. Even NASA is interested as the agency hopes that the study of Lake Vostok may provide clues to life at the extremes. NASA is particularly interested in Europa, a moon of the planet Jupiter, that is thought to have an ocean of water beneath a thick mantle of ice. If life exists in the extreme conditions at Vostok, it would provide hope that the same might be true of the, as yet unproven, ocean beneath the surface of Europa.

The conditions at Vostok are harsh, boasting the world’s lowest recorded temperature of -128 F in 1983. The lake water is thought to stay liquid through a combination of insulation by the ice coat, possible geothermal vents and pressure from the ice of around 2.5 tons per square inch. This is enough to maintain liquid water at a balmy -4 degrees Celsius, according to Monastersky. Warm enough for some types of bacteria to survive and, Gabrielle Walker reports in the Dec. 4, 1999, issue of New Scientist, enough nutrients have been found in the ice core at depths of a little more than two miles to safely assume that sufficient food for microbial life also exists in the waters of Lake Vostok.

The Russians have drilled through the glacier to within 300 feet of the lake, but stopped for fear that kerosene used to lubricate the drill and keep the hole above it from freezing, plus organic debris stuck to the drill, would contaminate the pristine waters. Siegert says several proposals have been made to sample the lake without contaminating it with the best option being a robotic probe that would melt its way down the remaining distance with the hole sealing shut behind it.

Once in the lake, the probe would send back data through an attached wire from a variety of onboard sensors and probes. This would not answer the main question of whether microorganisms live in the frigid waters. For this, a means of capturing water samples and bringing them to the surface with minimal contamination has to be devised. No one has come up with an answer as yet but, given the potential scientific riches to be mined from Lake Vostok, it almost certainly will be done in the next few years.

Clair Wood taught physics and chemistry for more than a decade at Eastern Maine Technical College in Bangor.