Isotopologue data reveal bacterial denitrification as the primary source of N2O during a high flux event following cultivation of a native temperate grassland
Abstract
The source of N2O in terrestrial ecosystems has long been debated. Both nitrification and denitrification produce N2O but their relative importance remains uncertain. Here we apply site preference, SP (the difference in δ15N between the central and outer N atom in N2O), to estimate the relative importance of bacterial denitrification (including nitrifier denitrification) to total N2O production from soil. We measured SP over a diurnal cycle following the third year of tillage of a previously uncultivated grassland soil at the Kellogg Biological Station (KBS) in southwestern Michigan. Fluxes of N2O in our study ranged between 7.8 and 12.1 g N2O–N ha−1 d−1 and were approximately 3 and 10 times greater than fluxes observed in managed agricultural and successional fields, respectively, at KBS. Consequently, our study captured a period of high flux resulting from the cultivation of a historically never-tilled soil. Concentration weighted SP values decreased from 12.9‰ in the morning to a minimum value of −0.1‰ in the afternoon.
Based on SP values reported for bacterial denitrification (−5 to 0‰; Toyoda et al., 2005; Sutka et al., 2006), hydroxylamine oxidation (nitrification) and fungal denitrification (33–37‰; Sutka et al., 2006) we found that production attributable to bacterial denitrification increased from between 52.9 and 60.9% in the morning to between 87.5 and 100% in the afternoon. Further, we observed diurnal variation in flux and SP that is consistent with increased production from bacterial denitrification associated with temperature-driven increases in respiration.
Department
Soil Biogeochemistry and Microbial Ecology
Publication Date
12-18-2009
Journal Title
Soil Biology and Biochemistry
Publisher
Elsevier
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
Nathaniel E. Ostrom, Robin Sutka, Peggy H. Ostrom, A. Stuart Grandy, Kristin M. Huizinga, Hasand Gandhi, Joseph C. von Fischer, G. Philip Robertson, Isotopologue data reveal bacterial denitrification as the primary source of N2O during a high flux event following cultivation of a native temperate grassland, Soil Biology and Biochemistry, Volume 42, Issue 3, 2010, Pages 499-506, ISSN 0038-0717, https://doi.org/10.1016/j.soilbio.2009.12.003.
Rights
© 2009 Elsevier Ltd. All rights reserved.