Xinning Zhang is an environmental microbiologist jointly appointed in the Department of Geosciences and the Princeton Environmental Institute. Zhang’s research aims to provide a mechanistic understanding of how microbial metabolism influences biogeochemical cycling and climate in modern and ancient environments. To determine the key parameters explaining microbial activities and their signatures in the rock record, she applies tools from microbial physiology, molecular ecology and stable isotope geochemistry to lab and field research. She earned her Ph.D. in environmental science and engineering from the California Institute of Technology and a B.S. in biological and environmental engineering from Cornell University.