Open AccessThe influence of synthetic sheep urine on ammonia oxidizing bacterial communities in grassland soil
Author(s) -
Mahmood Shahid,
Prosser James I.
Publication year - 2006
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2006.00070.x
Subject(s) - microcosm , biology , temperature gradient gel electrophoresis , ammonia , urine , nitrification , nitrate , grassland , relative species abundance , soil water , abundance (ecology) , ecology , bacteria , environmental chemistry , 16s ribosomal rna , nitrogen , biochemistry , chemistry , genetics , organic chemistry
In grazed, grassland soils, sheep urine generates heterogeneity in ammonia concentrations, with potential impact on ammonia oxidizer community structure and soil N cycling. The influence of different levels of synthetic sheep urine on ammonia oxidizers was studied in grassland soil microcosms. ‘Total’ and active ammonia oxidizers were distinguished by comparing denaturing gradient gel electrophoresis (DGGE) profiles following PCR and RT‐PCR amplification of 16S rRNA gene fragments, targeting DNA and RNA, respectively. The RNA‐based approach indicated earlier, more reproducible and finer scale qualitative shifts in ammonia oxidizing communities than DNA‐based analysis, but led to amplification of a small number of nonammonia oxidizer sequences. Qualitative changes in RNA‐derived DGGE profiles were related to changes in nitrate accumulation. Sequence analysis of excised DGGE bands revealed that ammonia oxidizing communities in synthetic sheep urine‐treated soils consisted mainly of Nitrosospira clusters 2, 3 and 4. Nitrosospira cluster 2 increased in relative abundance in microcosms treated with all levels of synthetic sheep urine. Low levels additionally led to increased relative abundance of Nitrosospira cluster 4 and medium and high levels increased relative abundance of cluster 3. Synthetic sheep urine is therefore likely to influence the spatial distribution and composition of ammonia oxidizer communities, with consequent effects on nitrate accumulation.