In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 76, No. 6 ( 2010-03-15), p. 1870-1878
Abstract:
The objective of this study was to investigate how changes in soil pH affect the N 2 O and N 2 emissions, denitrification activity, and size of a denitrifier community. We established a field experiment, situated in a grassland area, which consisted of three treatments which were repeatedly amended with a KOH solution (alkaline soil), an H 2 SO 4 solution (acidic soil), or water (natural pH soil) over 10 months. At the site, we determined field N 2 O and N 2 emissions using the 15 N gas flux method and collected soil samples for the measurement of potential denitrification activity and quantification of the size of the denitrifying community by quantitative PCR of the narG , napA , nirS , nirK , and nosZ denitrification genes. Overall, our results indicate that soil pH is of importance in determining the nature of denitrification end products. Thus, we found that the N 2 O/(N 2 O + N 2 ) ratio increased with decreasing pH due to changes in the total denitrification activity, while no changes in N 2 O production were observed. Denitrification activity and N 2 O emissions measured under laboratory conditions were correlated with N fluxes in situ and therefore reflected treatment differences in the field. The size of the denitrifying community was uncoupled from in situ N fluxes, but potential denitrification was correlated with the count of NirS denitrifiers. Significant relationships were observed between nirS , napA , and narG gene copy numbers and the N 2 O/(N 2 O + N 2 ) ratio, which are difficult to explain. However, this highlights the need for further studies combining analysis of denitrifier ecology and quantification of denitrification end products for a comprehensive understanding of the regulation of N fluxes by denitrification.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.02484-09
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2010
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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