Abundance and population structure of ammonia-oxidizing bacteria that inhabit canal sediments receiving effluents from municipal wastewater treatment plants

A polyphasic, culture-independent study was conducted to investigate the abundance and population structure of ammonia-oxidizing bacteria (AOB) in canal sediments receiving wastewater discharge. The abundance of AOB ranged from 0.2 to 1.9% and 1.6 to 5.7% of the total bacterial fraction by real-time PCR and immunofluorescence staining, respectively. Clone analysis and restriction endonuclease analysis revealed that the AOB communities influenced by the wastewater discharge were dominated by Nitrosomonas, were similar to each other, and were less diverse than the communities outside of the immediate discharge zone.