It's not just farms and forests that make soil valuable. Soil cycles ten times more carbon than all the power plants, factories, and vehicles in the world; its role in regulating atmosphere and climate makes soil essential to life on Earth.

"Because of carbon respiration and storage, soils could be a key determinant of how and when the global climate changes," says Margaret Torn of Berkeley Lab's Earth Sciences Division. "Yet soils are one of the aspects of the terrestrial carbon cycle we know least about."

Torn became intrigued with the living world when her family moved from Los Angeles to rural Marin County. She was 11; walking the hills every day, she wondered about human impacts on nature. Then, as a teenager, political setbacks to environmental initiatives made her determined to apply her math and science skills to studying and protecting ecosystems.

Torn studied natural history at the College of Marin; it made her a fan of the community college system. "We had committed teachers who got us out of the classroom. I learned to recognize all the trees and bird species in the county."

She transferred to UC Berkeley, where one of her professors was studying acid rain in the Colorado Rockies. After working at the site, "I was hooked — I knew I had to spend my career doing fieldwork."

Torn worked her way through college, graduated with highest honors, and entered Berkeley's graduate Energy and Resources program. Meanwhile she found time to coauthor In Our Own Hands, an influential book about California's biological diversity.

Her focus was on the relationship of local processes to global phenomena — "how, for example, the methane flux of a single wetland contributes to controlling the temperature of the whole Earth." After receiving her Ph.D. in 1994, Torn went on to postdoctoral fellowships with two scientists she considers "the best in the world" in their fields: Susan Trumbore of UC Irvine, an expert in isotope geochemistry, and ecologist Peter Vitousek at Stanford.

Torn joined Berkeley Lab in 1998. "It's a great combination: good facilities, wide-ranging intellectual interests, and close collaborations on the UC campus . . . plus a view of the Bay that can't be beat!"

Determined to bring exactness to ecology, Torn has become a national expert on how terrestrial ecosystems affect the carbon cycle, and how humans are altering the natural process. Her fieldwork has taken her to many sites, including Hawaiian volcanoes, Alaskan tundra, and the Russian steppes. She says field work is essential to ecology. "You may have a great theory, but when you test it in the field, you often find you are wrong."

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