Dissertation Research: Effects of Increasing Nitrogen Inputs on Microbial Immobilization, Soil Nitrogen Retention, and Denitrification in an Aggrading Forest Ecosystem

Duke University, Durham NC

Investigators

Abstract

Nitrogen deposition has increased in several regions in the United States due to inadvertent emissions from agro-industrial activities. This project is designed to investigate three important fates for nitrogen inputs in temperate forests: microbial immobilization, incorporation into slowly decomposing soil organic matter, and denitrification gas emissions. The ability of these sinks to retain nitrogen inputs may determine the sustainability of forest ecosystems and may affect global warming and aquatic ecosystem health. For example, as nitrogen inputs increase, increased denitrification may result in increased emissions of nitrous oxide, a potent greenhouse gas. This project will investigate the ability of soils to retain nitrogen through biotic (microbial) and abiotic (physiochemical) mechanisms, and the response of denitrification to changes in environmental conditions and changes in microbial biodiversity. The results of this study will be critical to predicting the response of forest ecosystems to increasing nitrogen deposition.