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.

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.

Tulaczyk and others still don't know which theory best explains the microbes found in these subglacial lakes, but he and others are tantalized by the prospect that their presence indicates even more complex life forms could be dwelling in the deep.

“This may sound far-fetched at the first glance, but without further studies I wouldn’t rule out worms or sponges living down there or other life forms that tend to be more resilient in terms of survival,” Tulaczyk says. “And of course, any more complex life forms are likely to be an entirely new species, given the length of isolation from the rest of the genetic pool.”

Given the utterly inhospitable conditions of subglacial lakes, that may sound like a long shot. But an experiment at Lake Vostock has provided optimism. Recently, scientists studied the composition of refrozen lake water sampled at the bottom of an ice core, finding compounds extremely similar to those associated with fish-filled waters. Tulaczyk doubts that fish are swimming beneath the ice in Lake Whillans, but the mere possibility is too enticing to ignore.

The idea that life can survive, and even thrive, in such a desolate environment doesn’t only resonate with Earth-bound explorers.

In the last few decades, NASA probes have discovered a giant ocean beneath miles of ice on Europa, one of Jupiter’s moons. (A future probe may specifically search for life beneath the ice.) Other ice-covered moons are known to orbit Jupiter and Saturn, leaving researchers pondering the possibility of life throughout our solar system.

The discovery at Lake Whillans makes this prospect all the more tantalizing; after all, according to Tulaczyk, the Antarctic subglacial environment resembles another planet more than it does Earth.

Yet glaciologists like Tulaczyk are once again racing against the clock in their efforts to study subglacial lakes. This time it isn't the approach of winter that is the problem—it's long-term climate change, and the prospect that these fast frozen reserves will disappear.

Already, the alarming increase in global temperatures is causing some parts of the Antarctic ice sheet to lose three to 30 feet a year. The problem is exacerbated by warming of Earth's oceans, which is accelerating the rate at which ice sheets are melting.

While glacial contact with warm air produces moderate melting, glacial contact with warm ocean water creates a faster melting rate—up to 10 times faster, meaning tens to hundreds of feet of melted ice per year.

And our oceans are heating up fast. Glacial ice near the coast of Antarctica is disappearing at unprecedented rates due to its constant contact with warming ocean water. And things may get much worse soon: Tulaczyk notes that many glaciologists point to a possible exponential increase in ice sheet retreat once climate change reaches a tipping point.

In the meantime, there is much work to be done while the ice remains.

Tulaczyk and his team hope to obtain samples from other subglacial lakes in order to compare findings. His colleagues will conduct sophisticated genetic analyses to learn how microbes survive in an isolated environment like Lake Whillans.

Space aliens may still be consigned to science fiction. But as Tulaczyk’s discovery reveals, we might have our own kinds of aliens right here on planet Earth.

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