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Impact of herbicides on the abundance and structure of indigenous β‐subgroup ammonia‐oxidizer communities in soil microcosms
Author(s) -
Chang YunJuan,
Hussain A. K. M. Anwar,
Stephen John R.,
Mullen Mike D.,
White David C.,
Peacock Aaron
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620201110
Subject(s) - microcosm , temperature gradient gel electrophoresis , population , biology , ammonia monooxygenase , library , microbial population biology , proteobacteria , abundance (ecology) , microbiology and biotechnology , environmental chemistry , 16s ribosomal rna , chemistry , ecology , bacteria , genetics , archaea , demography , sociology
In this study, mixtures of five herbicide‐formulated products (atrazine, dicamba, fluometuron, metolachlor, and sulfentrazone) were applied to soil microcosm columns in increasing concentrations. The toxic impact of herbicides on the indigenous β‐subclass Proteobacteria autotrophic ammonia‐oxidizer (β‐AAO) community was assessed. The β‐AAO population abundances were estimated by competitive polymerase chain reaction (PCR) targeting the gene amoA , encoding the α‐subunit of ammonia monooxygenase. Community structure was examined by PCR and denaturing gradient gel electrophoresis targeting 16S rDNA with band excision and sequence analysis, and by analysis of amoA gene fragment clone libraries. The 16S rDNA analyses showed that a single ribotype of Nitrosospira cluster 3 was the dominant β‐AAO in all treatments. At a finer scale, amoA clone library analysis suggested a shift in community structure corresponding to the 100‐ppm application. Competitive PCR indicated significant differences between treatments. The control exhibited relatively stable population abundance over the time period examined. The 10‐ppm treatment induced a population increase, but a significant decrease was induced by the 100‐ppm application. At 1,000 ppm, the ammonia‐oxidizer population dropped below the method detection limit by the first sampling point. An impact on ammonia oxidizers resulting from the application of herbicides was observed, both in abundance and community structure.