 |
| Titel |
The fate of N2O consumed in soils |
| VerfasserIn |
B. Vieten, F. Conen, B. Seth, C. Alewell |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 1 ; Nr. 5, no. 1 (2008-02-01), S.129-132 |
| Datensatznummer |
250002232
|
| Publikation (Nr.) |
 copernicus.org/bg-5-129-2008.pdf |
|
|
|
|
|
| Zusammenfassung |
| Soils are capable to consume N2O. It is generally assumed that
consumption occurs exclusively via respiratory reduction to N2 by
denitrifying organisms (i.e. complete denitrification). Yet, we are not
aware of any verification of this assumption. Some N2O may be
assimilatorily reduced to NH3. Reduction of N2O to NH3 is
thermodynamically advantageous compared to the reduction of N2. Is this
an ecologically relevant process? To find out, we treated four contrasting
soil samples in a flow-through incubation experiment with a mixture of
labelled (98%) 15N2O (0.5–4 ppm) and O2 (0.2–0.4%) in
He. We measured N2O consumption by GC-ECD continuously and δ15N
of soil organic matter before and after an 11 to 29 day incubation
period. Any 15N2O assimilatorily reduced would have resulted in
the enrichment of soil organic matter with 15N, whereas dissimilatorily
reduced 15N2O would not have left a trace. None of the soils
showed a change in δ15N that was statistically different from
zero. A maximum of 0.27% (s.e. ±0.19%) of consumed
15N2O may have been retained as 15N in soil organic matter in
one sample. On average, 15N enrichment of soil organic matter during
the incubation may have corresponded to a retention of 0.019% (s.e. ±0.14%; n=4)
of the 15N2O consumed by the soils. We
conclude that assimilatory reduction of N2O plays, if at all, only a
negligible role in the consumption of N2O in soils. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|