湛江湾沉积物中反硝化和厌氧氨氧化细菌的丰度、多样性及分布特征

The diversity and abundance of denitrifying bacteria and anammox bacteria in Zhanjiang Bay sediments were analyzed by real-time fluorescent quantitative PCR and high-throughput sequencing. The results show that the abundance of denitrifying bacteria and anammox bacteria in the sediments changed significantly in season and location. The nirS-type denitrifying bacteria were the highest in February and the lowest in April, and its average abundance tends to increase first and then decrease from inside to outside of the bay. The abundance of nirK-type denitrifying bacteria were the highest in September and the lowest in November. The nosZ-type denitrifying bacteria were the highest in April, and did not change in other months. The abundance of anammox bacteria were the highest in September and the lowest in February. Correlation analysis showed that nitrite and ammonium jointly regulated the changes of denitrifying and anammox bacteria abundances in the sediments. Phylogenetic analysis showed that there are some widely distributed denitrifying bacteria in Zhanjiang Bay, but certain novel nirK and nosZ-type denitrifying bacteria were also found. For anaerobic ammonium oxidizing bacteria, it mainly belongs to the Planctomycetes and Candidatus scalindua, which is high-salinity tolerated. In addition, a new branch of anammox bacteria inhabited in Zhanjiang Bay that are not found elsewhere. CCA analysis showed that nitrate significantly affected the community structure of denitrifying bacteria and anammox bacteria in the sediments. There are competition between denitrifying bacteria and anammox bacteria, which is driven by various environmental factors including nitrite, nitrate, and pH.