Testing a conceptual model of the terrestrial nitrogen cycle including rapid stabilization of nitrogen in soil

Human activities have doubled annual reactive nitrogen inputs to the biosphere with major implications for water and air quality. Recent studies show that most inorganic nitrogen is rapidly converted to organic form and efficiently retained in soils for decades. This proposal will measure the rate and magnitude of nitrogen retention in stable soil organic matter of forest, urban, and agricultural ecosystems. The research is guided by a conceptual model for the nitrogen cycle that explicitly includes a stable organic pool and its dynamics. The proposal focuses on three questions: What are the rate and magnitude of nitrogen retention in stable soil organic matter? What is the relative contribution of the microbial pathway in stable nitrogen formation? What are the molecular structures of the organic nitrogen forms?

Results will be integrated into high school curricula by a participant with expertise in experiential learning and high school science instruction, linking to Pennsylvania State Standards of Learning for the Environment and Ecology, the newest learning standards in the state. Undergraduate students from underrepresented groups will be recruited using established programs. The work will also link three junior level scientists from diverse fields of ecology, chemistry and education.