How Life Began

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Deming's specialty is sea ice, which may look solid, but is actually riddled with tiny channels and pores filled with very salty water. Microbes that live in sea ice have to survive temperatures that vary from just below freezing to -31[degrees]F. And although Deming is just beginning to understand how they do it, she has learned that at least one genus is closely related to bacteria that live in the deep ocean--suggesting that the adaptations to cold and to high pressure are somehow linked.

This is good news for scientists who hope to find life on Europa, a moon of Jupiter's that is covered with ice but probably has an ocean beneath. According to Deming, indirect analyses of Europa's surface suggest that it contains salts, and that they are the same salts found in Earth's oceans; any microbes that exist on Europa might resemble the ones she has found.

They might be even more similar to the bugs Montana State's Priscu is sure lurk in Lake Vostok, not just in its near freezing waters but in the hundreds of feet of sediment he believes lie at the bottom. Russian drillers and their international collaborators aren't going to penetrate the lake itself until they have designed a system that won't taint the pristine water with contaminants from higher up. But when they do--probably within the next few years--they will be able to see what's going on in a nearly perfect analogue of Europa's oceans. And the techniques they develop will be applicable to eventual searches for life on that distant moon. "It's humbling," Priscu says, "to find microbes where you never imagined they could exist."

It's also clear that there are plenty of surprises left. Says Priscu: "In the '70s, when I first got interested in this field, many colleagues called claims of life in extreme environments 'hand waving.'" Since then, he and the other extremologists have found life inside glaciers, at the bottom of mines, in searing heat, freezing cold, crushing pressure and lethal toxicity. And that's after exploring only a tiny fraction of the planet. What they have discovered so far has transformed biology. What they will find next is anybody's guess.