Lake Vostok - Research

Research

Researchers working at Vostok Station produced one of the world's longest ice cores in 1998. A joint Russian, French, and United States team drilled and analyzed the core, which is 3,623 m (11,886 ft) long. Ice samples from cores drilled close to the top of the lake have been assessed to be as old as 420,000 years. The assumption is that the lake has been sealed from the surface since the ice sheet formed, 15 million years ago. Drilling of the core was deliberately halted roughly 100 m (300 ft) above the suspected boundary between the ice sheet and the liquid waters of the lake. This was to prevent contamination of the lake from the 60 ton column of Freon and kerosene Russian scientists filled the borehole with to prevent it from collapsing and freezing over.

From this core, specifically from ice that is thought to have formed from lake water freezing onto the base of the ice sheet, extremophile microbes were found, suggesting that the lake water supports life. Scientists suggested that the lake could possess a unique habitat for ancient bacteria with an isolated microbial gene pool containing characteristics developed perhaps 500,000 years ago.

In January 2011, the head of the Russian Antarctic Expedition, Valery Lukin, announced that his team had only 50 m (200 ft) of ice left to drill in order to reach the water. The researchers then switched to a new thermal drill head with a "clean" silicone oil fluid to drill the rest of the way. Instead of drilling all the way into the water, they said they would stop just above it when a sensor on the thermal drill detected free water. At that point, the drill was to be stopped and extracted from the bore hole. Removal of the drill would lower the pressure beneath it, drawing water into the hole to be left to freeze, creating a plug of ice in the bottom of the hole. Drilling stopped on 5 February 2011 at a depth of 3,720 m (12,200 ft) so that the research team could make it off the ice before the beginning of the Antarctic winter season. The drilling team left by aircraft on 6 February 2011.

By plan, the following summer, the team was to drill down again to take a sample of that ice and analyze it. The Russians resumed drilling into the lake in January 2012 and reached the upper surface of the water in 6 February 2012.

In the Antarctic summer of 2012–13, the Russian team also plans to send an underwater robot into the lake to collect water samples and sediments from the bottom. Sediments on its floor should give clues to its long-term climate, and isotopes in its water are expected to help glaciologists determine how and when subglacial lakes such as Lake Vostok form. An environmental assessment of the plan will be submitted at the Antarctic Treaty's consultative meeting in May 2012.