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Dianne K. Newman
She has mastered the languages, techniques, and cultures of both fields to get to the crux of her work: using modern bacteria to understand how the first bacteria on earth could have survived.
The only way to extrapolate how—and when—early bacteria thrived is to study the relics they left behind: rocks. So Newman is probing how bacteria interact with minerals. She's discovered how some bacteria produce energy from arsenic and iron and how they change their environments in the process. She thinks some of the oldest bacteria—those that existed before the atmosphere resembled its current, oxygen-dominated state—relied heavily on iron to drive their metabolisms. Today, the remnants of a long-ago iron-rich environment are visible as striking red bands on ancient canyon walls, and Newman's work is relevant for explaining those patterns.
“Choosing bacteria that can be worked with genetically really set her apart from her peers in the geosciences,” says her former teacher Thomas Silhavy, a Princeton University microbiologist. “She realized that genetic analysis opens all the doors for molecular sciences. You could argue that she created the field of geomicrobiology.”
Newman's work has crossed over into modern medicine and ecology as well, helping explain how modern bacteria thrive in unusual settings—from the mucus-filled lungs of cystic fibrosis patients to arsenic-contaminated streams. Learning what keeps the bacteria alive could lead to novel ways to thwart their growth.
As an undergraduate at Stanford University, Newman never guessed she'd end up as a microbiologist. She majored in German studies and took a lot of environmental and materials science classes. “I loved everything, that was my problem,” she says. “I was an advising nightmare.” She believed in doing what she loved, she says. If one day that was German and the next engineering, why not? That's still how she conducts research, following the ever-winding path of her interests.
But as graduation loomed, Newman had to nail down something to do next. She chose environmental engineering—a combination of some of the things that had fascinated her most at Stanford—and began a graduate program at MIT.
With no real engineering experience, she had to push to find a professor who would take her on. “Even though I said ‘No thanks' six or seven times, she really wanted to work with me,” says François Morel, who studies how microorganisms interact with metals—a topic that intrigued Newman. Her persistence paid off and Morel finally became her advisor.
In Morel's lab though, Newman says she didn't have the patience for the first project he gave her: studying how phytoplankton respond to silver. Beakers for these experiments needed to be washed repeatedly in acid baths to rid them of metal contamination. “I realized that multiple acid-washing would probably drive me crazy after a while,” says Newman, “so I asked if I could switch.”
Photo: Leah Fasten