Russian scientists prepare to break through into Lake Vostok.

Lake Vostok is a subglacial lake under the East Antarctic Ice Shelf. It is about 500 m below sea-level, but is buried under 4 km of ice. The lake is approximately 250 km long, by 50 km wide and has an average depth of 344 m. Lake Vostok was covered by the ice between 14 and 25 million years ago, when Antarctica was still attached to South America and possibly Australia. The Lake will not have been completely isolated for all of this time; most of the water currently in it is likely to have come from the bottom of the glacial ice-sheet.

Map of Antarctica, showing the location of Lake Vostok. California Academy of Sciences.

A team of Russian scientists and engineers from the Arctic and Antarctic Research Institute has been drilling towards Lake Vostok each short Antarctic summer since 1990 (they were a team of Soviet scientist and engineers when they started out), with an eight year pause from 1998, when the scientists stopped 100 m short of their goal to evaluate how to make the final drill into the lake in a safe and sterile way. They are now expected to make the final breakthrough within the next week; if anything should go wrong and they are unable to complete the drilling process before the end of February, then they will be forced to withdraw for another year. During the Antarctic winter temperatures on the East Antarctic Ice Sheet can fall to -100 °C, conditions which would prevent work by the most hardy of researchers.

A diagrammatic cross section through Lake Vostok, showing the progress of the Russian drill.

While bacteria and other micro-organisms have been recovered from the ice throughout the drilling process, the Russian team have always regarded these as contaminants (some have been described in scientific articles by American researchers). It is thought likely that Lake Vostok will contain an ecosystem that has been isolated from the outside world for tens of millions of years, and that will be rich in extremophilic organisms (organisms that thrive in extreme conditions), an environment that the researchers are keen to avoid contaminating.

The other consideration is safety; Lake Vostok is thought to be very rich in dissolved gasses, to the extent that some researchers believe that an uncontrolled release of pressure might cause up to a quarter of the water in the lake to escape suddenly, like a carbonated drink that has been shaken from a bottle. This would not only probably be fatal to anyone working at the drill-head, it would be likely to cause a permanent change in the climate of Antarctica due to the amount of water vapor released.

The Lake Vostok Drilling Station.

Despite the precautions the Russians are taking, they are still facing criticism from some sources. The Antarctic and Southern Ocean Coalition, an umbrella group representing environmental organizations concerned about the Antarctic is usually supportive of research projects, but has questioned some of the methods used by the Russian group, particularly the use of drill-lubricants and anti-freeze, which could potentially contaminate the lake.

Many scientists regard attempts to drill into subglacial lakes in Antarctica as practice for potential future attempts to look for life elsewhere in the solar system, particularly on the Jovian Moon Europa and Saturn's Moon Enceladus, both of which are thought to have oceans beneath their icy exteriors.

See also Drilling for Lake Ellsworth, Fossil beaked whales from the seafloor of the Southern Indian Ocean, New deep-sea hydrothermal vent ecosystem discovered in the Southern Ocean and New study of Europa's 'chaos terrains' reveals subsurface lakes, but not oceans.

Drilling for Lake Ellsworth.

Lake Ellsworth is a sub-glacial lake in West Antarctica, it is about 70 km west of the Ellsworth Mountains, and approximately 3.4 km beneath the West Antarctic Ice Shelf. The lake has a long narrow throat and is thought to be about 150 m deep, and to cover an area of about 29 km³, about the same size as Lake Windermere. It is one of about 400 subglacial lakes in Antarctica, insulated from outside world by the overlying glaciers, and kept above freezing by heat from the Earth's interior, these lakes often flow for long distances, none lake emptying into another. They are of extreme interest to scientists since they have been cut off from the outside world since the overlying glaciers formed, in West Antarctica about 150 000 years ago, and any life there will have been evolving in isolation for all that time, in extremely strange and harsh conditions; cold, dark and low in nutrients. The sediments bellow the lake will also tell us a lot about the climate at the time the lakes formed.

The location of Lake Ellsworth.

Lake Ellsworth is the subject of a British mission to drill through the ice and recover water and sediment samples from beneath the ice. A team of engineers has just returned to the UK having towed 7o tonnes of drilling equipment 250 km though the Ellesworth Mountains to the drilling site, in temperatures as low as -35 °C. The equipment is now 1.7 km from the Lake, at a sheltered site where it will be protected during the harsh Antarctic winter. Engineers and scientists will return to the site in December 2012, when the equipment will be moved into its final position and drilling will commence.

The drill will use hot water to bore a 360 mm borehole slowly through the ice. Once the drill is turned off the hole should reseal in about 24 hours. The borehole will be kept sterile using a powerful ultraviolet filtering system. Once the borehole is complete a probe will be used to collect water from the lake, and a sediment corer to collect sediment from beneath it.

The location of Lake Ellsworth beneath the ice, and how the drill will reach it. Not to scale.

A Russian team has been drilling towards Lake Vostok, on the East Antarctic Ice Sheet, and thought to be Antarctica's largest lake, for some years. They were within 29 m of the lake in February 2011, when they were forced to stop drilling due to the onset of the Antarctic winter, with drilling resuming in December 2011; they hope to break through to the lake early in 2012. In the winter of 2012-13 the Russian team hope to launch a robotic probe into the lake. An American project, the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD), hopes to start drilling towards Lake Whillans beneath the West Antarctic Ice Sheet in 2013. They also hope to launch a remote rover vehicle into the sub-glacial lake. Many scientists view these missions as good practice for any future mission to the sub-glacial ocean thought to exist on Jupiter's moon Europa.

See also New deep-sea hydrothermal vent ecosystem discovered in the Southern Ocean and New study of Europa's 'chaos terrains' reveals subsurface lakes, but not oceans.