In:
Rapid Communications in Mass Spectrometry, Wiley, Vol. 18, No. 11 ( 2004-06-15), p. 1201-1207
Abstract:
Nitrifiers and denitrifiers are the main producers of the greenhouse gas nitrous oxide (N 2 O). Knowledge of the respective contributions of each of these microbial groups to N 2 O production is a prerequisite for the development of effective mitigation strategies for N 2 O. Often, the differentiation is made by the use of inhibitors. Measurements of the natural abundance of the stable isotopes of N and O in N 2 O have been suggested as an alternative for the often unreliable inhibition studies. Here, we tested the natural abundance incubation method developed by Tilsner et al . 1 with soils from four European grasslands differing in long‐term management practices. Emission rates of N 2 O and stable isotope natural abundance of N 2 O and mineral N were measured in four different soil incubations: a control with 60% water‐filled pore space (WFPS), a treatment with 60% WFPS and added ammonium (NH 4 + ) to support nitrifiers, a control with 80% WFPS and a treatment with 80% WFPS and added nitrate (NO 3 − ) to support denitrifiers. Decreases in NH 4 + concentrations, linked with relative 15 N‐enrichment of residual NH 4 + and production of 15 N‐depleted NO 3 − , showed that nitrification was the main process for mineral N conversions. The N 2 O production, however, was generally dominated by reduction processes, as indicated by the up to 20 times larger N 2 O production under conditions favouring denitrification than under conditions favouring nitrification. Interestingly, the N 2 O concentration in the incubation atmospheres often levelled off or even decreased, accompanied by increases in δ 15 N and δ 18 O values of N 2 O. This points to uptake and further reduction of N 2 O to N 2 , even under conditions with small concentrations of N 2 O in the atmosphere. The measurements of the natural abundances of 15 N and 18 O proved to be a valuable integral part of the natural abundance incubation method. Without these measurements, nitrification would not have been identified as essential for mineral N conversions and N 2 O consumption could not have been detected. Copyright © 2004 John Wiley & Sons, Ltd.
Type of Medium:
Online Resource
ISSN:
0951-4198
,
1097-0231
Language:
English
Publisher:
Wiley
Publication Date:
2004
detail.hit.zdb_id:
2002158-6
detail.hit.zdb_id:
58731-X
SSG:
11
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