Abundance, diversity, and community composition of anammox bacteria in sediments of Xiangshan Bay, China

Abstract Xiangshan Bay (XSB) is a typical semi-closed bay rich in dissolved inorganic nitrogen and anammox is one of the important processes of nitrogen cycle. The anammox bacterial abundance and diversity in XSB sediments was investigated. Five known genera were detected based on the anammox bacterial 16S rRNA gene, namely, Ca. Scalindua, Ca. Brocadia, Ca. Kuenenia, Ca. Jettenia, and Ca. Anammoxoglobus, and hzo genes affiliating with Ca. Scalindua were also discovered. The anammox bacterial 16S rRNA and hzo genes in the sediments varied from 2.10 × 106 to 2.18 × 107 and from 2.90 × 106 to 5.48 × 108 copies/g (fresh weight), respectively. Pearson correlation analysis demonstrated that the abundance of the hzo gene was positively correlated with the concentration of NH 4 + but negatively correlated with salinity and pH. Redundancy analysis showed that salinity, dissolved oxygen, and temperature were the three main factors influencing the community composition of anammox bacteria obtained by the anammox bacterial 16S rRNA gene. These findings help us to further understand the distribution and community composition of anammox bacteria in estuary sediments.