Isolated from the rest of the planet for 14 million years, Lake Vostok may be the only body of water on Earth to contain no life whatsoever. However, if life is discovered, it will be a big boost for researchers hoping to find microorganisms on icy moons like Europa.
On Feb. 5, a Russian team became the first to breach Lake Vostok, after drilling down through more than two miles of Antarctic ice. To avoid contaminating the lake, their drill bit automatically withdrew as soon as it struck water. That water rose about 100 feet up the borehole, forcing the drilling fluid away from the lake. The water then froze.
Sergey Bulat of the Petersburg Nuclear Physics Institute in St. Petersburg, Russia, and colleagues have now analyzed the water (contaminated with some drilling fluid) that froze onto the drill bit,counting cells and looking for traces of DNA.
In preliminary results reported at the 12th European Workshop on Astrobiology in Stockholm this month, Bulat says, there were only about 10 cells in every milliliter. There was also DNA from four species of bacteria, but Bulat thinks none of the bacteria came from the lake.
He cautions that we cannot be sure that the upper layers of Lake Vostok are devoid of life, because microorganisms could be living at low densities that he could not reliably detect. “The concentrations expected for indigenous stuff are very low,” Bulat says.
It will not be possible to draw firm conclusions until the team returns to the area in December. They should be able to pull up more ice fromthe borehole, most of it uncontaminated by the drilling fluid.
Vostok is one of many subglacial lakes in Antarctica. There are plans to drill into two others, Lake Ellsworth and Lake Whillans.
Ellsworth might become the first Antarctic lake to yield life. A British team plans to drill into it within the next few months and lower in a probe that will collect samples of sediment from the bottom.
That gives the British scientists an advantage over the Russian team. Lake sediments are the most promising places to find life, but the Russians do not have a firm plan to drill into them as yet.
The sediments are produced as the ice sheet grinds slowly over the underlying rocks, and will contain mineral nutrients from the rocks that could sustain microorganisms. The pitch-black water will contain little for the bugs to eat, so it’s unlikely that there is much life there.