Isotope fractionation factors controlling isotopocule signatures of soil‐emitted N2O produced by denitrification processes of various rates

RATIONALE This study aimed (i) to determine the isotopic fractionation factors associated with N2O production and reduction during soil denitrification and (ii) to help specify the factors controlling the magnitude of the isotope effects. For the first time the isotope effects of denitrification were determined in an experiment under oxic atmosphere and using a novel approach where N2O production and reduction occurred simultaneously. METHODS Soil incubations were performed under a He/O2 atmosphere and the denitrification product ratio [N2O/(N2+N2O)] was determined by direct measurement of N2 and N2O fluxes. N2O isotopocules were analyzed by mass spectrometry to determine [delta]18O, [delta]15N and 15N site preference within the linear N2O molecule (SP). An isotopic model was applied for the simultaneous determination of net isotope effects (η) of both N2O production and reduction, taking into account emissions from two distinct soil pools. RESULTS A clear relationship was observed between 15N and 18O isotope effects during N2O production and denitrification rates. For N2O reduction, diverse isotope effects were observed for the two distinct soil pools characterized by different product ratios. For moderate product ratios (from 0.1 to 1.0) the range of isotope effects given by previous studies was confirmed and refined, whereas for very low product ratios (below 0.1) the net isotope effects were much smaller. CONCLUSIONS The fractionation factors associated with denitrification, determined under oxic incubation, are similar to the factors previously determined under anoxic conditions, hence potentially applicable for field studies. However, it was shown that the η18O/η15N ratios, previously accepted as typical for N2O reduction processes (i.e., higher than 2), are not valid for all conditions. Copyright © 2014 John Wiley & Sons, Ltd..

Medienart:

Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:29

Enthalten in:

Rapid communications in mass spectrometry - 29(2015), 3, Seite 269-282

Sprache:

Englisch

Beteiligte Personen:

Lewicka‐Szczebak, Dominika [VerfasserIn]
Well, Reinhard [Sonstige Person]
Bol, Roland [Sonstige Person]
Gregory, Andrew S [Sonstige Person]
Matthews, G. Peter [Sonstige Person]
Misselbrook, Tom [Sonstige Person]
Whalley, W. Richard [Sonstige Person]
Cardenas, Laura M [Sonstige Person]

Links:

Volltext
onlinelibrary.wiley.com
www.ncbi.nlm.nih.gov
search.proquest.com

Themen:

Isotopes
Ratios
Superconductors

doi:

10.1002/rcm.7102

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

OLC1957755865