She is a Professor in the Departments of Earth and Planetary Science and Environmental Science, Policy, and Management. She also has an appointment in the geochemistry group at Lawrence Berkeley National Laboratory. Her primary research interests are in geomicrobiology and environmental microbiology. Her group studies how microorganisms shape, and are shaped by, their natural environments. Her research group studies microbial communities, primarily using cultivation-independent approaches such as genomics (metagenomics) and community proteomics. They work on microbial dissolution and precipitation of minerals, the structure, properties, and reactivity of nanoparticles (many of which are formed by microorganisms), microbial ecology, and microbial evolution. Virtually all of their projects are tied to a field site. Current locations of study are Iron Mountain (northern California), the Angelo Reserve (northern California), the Rifle and East River sites, Colorado, Crystal Geyser, Utah