Uni-Bayreuth grafik-uni-bayreuth


Novak, M; Parra Suárez, S; Gebauer, G; Thoma, M; Buzek, F; Cejkova, B; Jackova, I; Stepanova, M; Prechova, E; Curik, J; Veselovsky, F; Valkova, I; Blaha, V; Fottova, D; Komarek, A: Relationship between nitrogen isotope ratios of NO3- and N2O in vertical porewater profiles through a polluted rain-fed peat bog, Soil Biology and Biochemistry, 123, 7-9 (2018), doi:10.1016/j.soilbio.2018.04.022

We report a combination of δ15N-NO3- and δ15N-N2O values along vertical porewater profiles through a Sphagnum-dominated, high-elevation peat bog. Our objective was to distinguish between N2O production from NO3- via denitrification and N2O consumption via reduction to N2. Nitrate-N in runoff was isotopically heavier than NO3--N in atmospheric deposition, indicating export of organically-cycled NO3-. Constant N2O concentrations in porewater profiles contrasted with a shift toward higher δ15N-N2O values upward. In the 60-30 cm depth interval, a significant negative correlation between δ15N-NO3- and δ15N-N2O values was observed. Higher δ15N values of residual NO3- in the deepest peat layer reflected higher rates of NO3- reduction. Isotopically heavier N2O-N at shallower depths corresponded to residual N2O following partial reduction to N2.

last modified 2018-05-07