How Snowflakes Created Life in a Subglacial Lake

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Alien Life—On Our Own Planet

Scientists have discovered life in a subglacial lake long thought too barren to sustain as much as a microbe. What does that mean for the possibility of life on other planets?

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Last January, Slawek Tulaczyk, a glaciologist at the University of California, stood on the Antarctic Ice Sheet and watched as a massive drill sprayed hot water into a hole.

Tulaczyk and his team faced a formidable task: Their hot water drill—the first of its kind—was pushing through a half mile of ice to access Lake Whillans, a massive subglacial lake hidden underneath.

For days, the drill had been steadily working its way through the ice, and by Tulaczyk’s calculation, it should have already reached the lake. But it hadn’t.

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In two weeks, the Antarctic summer would be over, forcing the team to abandon their work for nearly a year.

Tulaczyk and his colleagues finally reached the massive subglacial lake just before the freeze set in—and what he discovered there shocked the scientific community: Tulaczyk’s expedition, didn’t just reach water when it broke into the lake. It uncovered life.

Nearly 10 percent of Earth’s land area is trapped beneath glacial ice, and for decades, scientists assumed these subglacial lakes were little more than a lifeless abyss. For the first time in history, Tulaczyk and his team, working with a National Science Foundation grant, had uncovered irrefutable evidence that there’s more to subglacial lakes than barren darkness.

“When I first got involved in Antarctic drilling projects 20 years ago, the prevailing assumption was that the environments covered by the ice sheet were sterile,” says Tulaczyk. “No one even bothered to check if there was life there. There is no light, so photosynthesis is impossible. There’s barely any oxygen.”

That assumption changed in the mid-1990s when scientists found dormant or dead microbial cells in ice samples taken from above the massive subglacial Lake Vostock. Scientists were intrigued, but couldn’t confirm that the cells inhabited the lake itself, nor could they disprove speculation that the cells originated from drilling fluid in the borehole, rather than the ice itself.

But it was enough for Tulaczyk and other scientists to develop a hypothesis. After all, life had once been present in Antarctica: Millions of years ago, the continent was covered by lush vegetation, and as it froze over, some microbes could theoretically have adapted to the newly frigid environment.

Life might have also found its way into the lake through snowflakes, which often grow around microbial cells suspended in the atmosphere. As snowflakes become compressed into glacier ice, they are pushed ever-downward through the ice sheet. Eventually, these flakes could be pushed all the way through the ice, reaching the lake and releasing microbes into the water.