My research focuses on the effects of large-scale environmental perturbations such as climate change and acid rain on nutrient cycling in terrestrial ecosystems with an emphasis on soil biogeochemical processes. In my research I try to apply fundamental knowledge of soil processes to address ecosystem-scale questions. In most projects I have collaborated with people from a wide range of disciplines including plant physiologists, hydrologists, and atmospheric chemists. Recent projects involved experimental and modeling studies focusing on the impacts of increased N deposition and precipitation on Mojave Desert ecosystems. More specifically, I was interested in assessing potential linkages between below-ground biotic processes including fine root dynamics and microbial decomposition and abiotic processes such as carbonate weathering and precipitation. I have conducted research addressing the impacts of forest management on soils in the Lake Tahoe Basin. In a recent project we looked at the impacts of prescribed fire on nutrient emissions from soils to aquatic environments and the atmosphere. We looked at the effects of charcoal in pile burns on nutrient transformations in burn scars. In addition, we studied how long term irrigation in arid lands affect soil organic matter dynamics. More recently, I have become involved in studies assessing how contaminants present in treated wastewater enter the food stream if wastewater is used for irrigation of agricultural crops.