Update: Russian scientists have now confirmed that they have indeed breached Lake Vostok. It is the first time one of Antarctica鈥檚 subglacial lakes has been penetrated. According to an [in Russian], the drill entered the lake at 20.25 Moscow time on 5 February. Thirty to forty metres of water rose into the borehole, confirming that the drill had reached the lake itself and not a small pocket of liquid water above the lake surface.

Original story (7 February 2012):

A Russian drilling team is trying to confirm that they have finally hit Lake Vostok, a vast subglacial body of water hidden 3.5 kilometres beneath the surface of the Antarctic ice sheet (see map and diagram).

A spokesperson for the in St Petersburg told 快猫短视频 this morning that the drill made contact with water late last week and then automatically withdrew up the borehole, as planned.

That suggests the lake has been breached, but the team are now checking the level of water in the borehole and readings from pressure sensors to confirm that the water did come from the lake and not a pocket of water in the ice above the lake. Ice temperatures rise as you go deeper into the ice sheet, and approach melting point just above the lake, so the fact that the team hit liquid water doesn鈥檛 necessarily mean they鈥檝e reached the lake.

鈥淔or the time being we are waiting for official confirmation,鈥� said the spokesperson. An announcement is expected within the next two days.

No more drilling

Drilling stopped on 5 February and most of the team, led by Valerii Lukin, have left the area. Two team members have remained to monitor the borehole over the Antarctic winter.

Even if Lukin鈥檚 team have broken through the ice sheet to the lake, they will still need to wait nearly a year to sample its secrets.

To avoid contaminating Vostok with drilling fluid Lukin and his team planned from the start to pierce the roof of the sealed ice cave which encases the lake and then let pressure in the lake force water into the drill hole. The plan is to leave the lake water to freeze in the borehole and create a plug, preventing contamination. The team will return to sample it during the following austral summer.

Life, or nothing

Lake Vostok has been isolated from the surface for millions of years, and many hope it contains bizarre new life forms. At present, however, that seems unlikely. The drillers have already sampled wedges of accretion ice 鈥� lake water that has naturally frozen onto the underside of the ice sheet 鈥� and although some researchers claim it contains bacteria, others write this off as contamination.

Moreover, the ice above is loaded with bubbles of trapped air. That air has accumulated in the lake for millennia, boosting the oxygen concentrations in the water and creating a potentially toxic environment. Some say that as a result, it is likely that the lake is completely sterile.

That could be just as interesting. If Lake Vostok turns out to be sterile, that will make it the only place on Earth where there is water but no life.