Isotopic investigation of redox effects on nitrate partitioning in a forest soil
Ariel Mollhagen1
Though the U.S. and Canada have seen a decrease in nitrate (NO3) deposition since the 1990s, deposition of this and other reactive nitrogen (N) species is still far higher than a century ago. The fate of this N determines the potential effects on forest ecosystems. Past studies have shown that the majority of deposited N that is retained in forest ecosystems is held in soil and litter on a 1-2 year timescale. Few studies have linked N-partitioning in forest soils with oxic status and activity of other redox active species (such as iron (Fe) and manganese (Mn)). This study examines the fate of a 15N-NO3 tracer in a lab-scale soil slurry experiment, probing N transformation as a function of depth (4 horizons differing in physical and chemical properties) and oxic status (oxic and suboxic). Of particular interest are the coupled interactions of N, Fe, Mn, and organic matter.
1Cornell University, am2839@cornell.edu