Marty Frisbee is an Assistant Professor of Hydrogeology at Purdue University where he studies groundwater/surface-water interactions. He uses a combination of field hydrological measurements, geochemistry, and environmental isotopes to identify sources of baseflow, geochemical processes, and residence times of both pristine and human-impacted watersheds. This information is used to inform conceptual models of hydrological responses and response times to perturbations such as climate change and land-use and land-cover change.