PopSci's Fourth Annual Brilliant 10

Alexis Templeton

University of Colorado at Boulder

She explores red-hot undersea volcanoes to study weird metal-munching bacteria

Alexis Templeton slams the refrigerator door, enclosing herself in a 50-degree cocoon, then extracts a test tube from its Styrofoam cooler. "Look closely," she says. As she holds the tube up to the light, a few solid granules the color of a rusty nail slide into view. "The amazing thing about these bacteria is that they're able to survive just by oxidizing iron," she says.

They may be microscopic, but the creatures in Templeton's lab are tough. They thrive in environments once thought inhospitable to life, such as the scorching vents of undersea volcanoes. Unrelenting opportunists, they extract energy from iron and basalt rather than carbon. Templeton, 34, got her first glimpse of the role these bacteria play in the ocean while she was investigating submerged volcanoes near Hawaii. When she saw the unusual chemical signatures that mineral samples from the volcanoes produced, she suspected that living things were responsible. Inspired, she decided to investigate how bacteria were affecting the geology and chemistry of their surroundings-and to assess whether their activity was helping sustain critical undersea food chains. "I want to find out how they extract what they need to live, and how that process affects ocean dynamics," she says.

Templeton's quest often takes her nearly a mile beneath the ocean's surface, crammed into a five-foot-wide submersible with several other researchers. "You're all curled up on these little benches," she says. "Outside, it's an orange rust-covered world." Much of the life down there subsists on solidified lava, an iron- and manganese-rich compound known as volcanic glass. By directing x-rays at glass samples and reading the energy profiles that return, Templeton can determine which bacteria are present and how their metabolism might be changing the glass. She has discovered more than 40 new species of metal- and mineral-dependent bacteria; last year she won the first Rosalind Franklin Award for Young Investigators.

Templeton hopes to broaden notions of where life is possible. Mars's red color, for instance, is the result of iron-rich rocks, which could have harbored metal-dependent creatures. "For the longest time I wanted to be an astronaut," she says, "but I'd never want to be away from family and friends that long." Her current gig lets her stay grounded while studying life-forms that border on the
extraterrestrial.

-Elizabeth Svoboda