Marine nitrogen cycle is of the most significance to maintain marine ecological balance. Anaerobic ammonia oxidation (Anammox) -driven by anaerobic ammonia-oxidizing bacteria is an important way of promoting marine nitrogen removal. This study quantified the Anammox Bacteria by amx-16S rDNA through real-time quantitative PCR technology in the surface sediment of the Yangtze estuary adjacent area in the summer of 2011. Consequently, there is a preliminary understanding on the spatial distribution of Anammox Bacteria in Yangtze estuary adjacent area. The ratio between amx-16S rDNA and bacterial 16S rDNA copy numbers showed that Anammox Bacteria were in a small proportion of the total bacterial biomass. Correlation analysis showed that the spatial abundance distribution of Anammox Bacteria was closely related to environmental factors. Total organic carbon, salinity, and ammonium concentration played vital roles in regulating Anammox Bacteria abundances in this area. Combining amx-16S rDNA copy numbers with environmental factors provided the foundation information for the research of Anammox Bacteria, which will play an important role in assessing the coupling relationship of denitrification in the Yangtze estuary.
