page_title: Lake Vostok
section_title: Research
hierarchical_section_title: Lake Vostok / Research
caption_attribution_description: English: French, Soviet, and American scientists in the Vostok team photo with unprocessed ice cores. Cores coming out of the barrel are generally 4-6m long and are cut to 1m sections. The pictured ice columns are unprocessed cores. White containers in the background are used for transporting 1m sections. Source caption identifies this as being from GISP2. This actually is at Vostok. Español: Equipo de la base Vostok con núcleos de hielo sin procesar. Los núcleos extraidos suelen tener de 4 a 6 metros, pero son cortados en secciones de 1 metro. Los contenedores que se observan al fondo se utilizan para transportar estas secciones.
context_page_description: Lake Vostok is the largest of Antarctica's almost 400 known subglacial lakes.
  Lake Vostok is located at the southern Pole of Cold, beneath Russia's Vostok Station under the surface of the central East Antarctic Ice Sheet, which is at 3,488 m above mean sea level. The surface of this fresh water lake is approximately 4,000 m under the surface of the ice, which places it at approximately 500 m below sea level.
  Measuring 250 km long by 50 km wide at its widest point, it covers an area of 12,500 km² making it the 16th largest lake by surface area. With an average depth of 432 m, it has an estimated volume of 5,400 km³, making it the 6th largest lake by volume.
  The lake is divided into two deep basins by a ridge. The liquid water depth over the ridge is about 200 m, compared to roughly 400 m deep in the northern basin and 800 m deep in the southern.
  The lake is named after Vostok Station, which in turn is named after the Vostok, a sloop-of-war ship, which means "East" in Russian.
context_section_description: 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 was 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 with the 60-ton column of Freon and kerosene used to prevent the borehole 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 on 6 February 2012. The researchers allowed the rushing lake water to freeze within the bore hole and months later, they collected ice core samples of this newly formed ice and sent to the Laboratory for Glaciology and Environmental Geophysics in Grenoble, France, for analysis.
caption: Ice cores drilled at Vostok Station, which is seen in the background
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