Scientists have dreamed for years of breaking through the ice covering Antarctica’s Lake Vostok. Deep in the interior of the frozen continent, this lake is one of the least hospitable and most isolated environments on the planet, having been sealed in ice for 15 to 34 million years.
Yesterday a Russian group announced they’d drilled all the way through the two miles of ice that cover this lake. If they find any kind of life exists there, it raises hopes that life could exist elsewhere in the universe, including the permanently ice-covered oceans of Jupiter’s moon Europa or Saturn’s moon Enceladus.
A few decades ago, scientists thought all of Antarctica’s frozen lakes would be lifeless, but a few brave scientists have since pierced the ice and taken chilly dives into the smaller lakes, finding they were full of algae and other living things. (On my 1995 trip to Antarctica, I watched drysuit- wearing divers perform this feat.)
If life exists in Lake Vostok, it will represent an extreme form of adaptation. No sunlight penetrates into the lake, so anything that got trapped there would have had to evolve some new way of getting energy.
This story from AP and printed in the Washington Post does a nice job of putting this into the context of other forms of life found in extreme environments:
“What makes Lake Vostok more important than other extreme environments is its incredible isolation.
For example, in Atacama, life probably blew in from elsewhere, NASA astrobiologist Chris McKay said. But Lake Vostok microbes, if found, could not have blown in.
More than 10 million years ago there was little or no ice there, so life could easily have existed then. But with no heat or sunlight after the ice set in, life there now would have had to find another way of getting energy, said molecular chemist and astrobiologist Steve Benner. And that’s key.
If life finds a way to adapt to strange conditions in this awful place, why couldn’t it live on Jupiter’s moon Europa or Saturn’s moon Enceladus, scientists ask. Both bodies have water trapped under crusts of ice, just like Lake Vostok, and are both prime targets in the search for life beyond Earth. The big disagreement among scientists is not about the potential for life on those two moons, but which one has the most potential and should be explored first.
It also means Mars could harbor life deep underground, McKay said.
“The broadest lesson that I think we can derive is that given liquid water, life can negotiate just about everything else,” McKay said.
So far, except for the surprise shrimp that stunned a NASA Antarctic researcher and the odd tubeworms alongside ocean vents, most of the life forms are so small we can’t see them. They are single-cell microbes or a tad more complex.
But that’s a big deal because microbes evolve. For 90 percent of the time that life existed on Earth, there were only microbes, said Bruce Jakosky, a professor of geological sciences at the University of Colorado. Microbes are “where we come from,” he said.
Jakosky and McKay said it also could eventually mean that life started in more than one place in the universe.
The AP story is a little confusing, saying at the start that the lake was untouched by light or wind for 20 million years, then quoting a scientist saying that 10 million ago there was little or no ice there so life could easily have existed. A similar story in the New York Times says the ice cover goes back 15 to 34 million years.
Scientists say it may take them some time to test the lake for life, but the world will be eagerly awaiting their results.