Peter M. Groffman is a Senior Scientist at the Institute of Ecosystem Studies in Millbrook, New York. His research interests include ecosystem, landscape, and microbial ecology, with a focus on carbon and nitrogen dynamics. His specific recent research efforts have focused on the investigation of snow depth as a regulator of soil freezing and nitrogen dynamics; and carbon and nitrogen cycling in urban watersheds and ecosystems. He has also researched the effects of a whole watershed calcium addition and exotic earthworm invasion on soil nitrogen and carbon cycling. In 2007 he served NEON as a site visit team member.