Landscape water is an important part of urban water systems, and excessive nitrogen affects its ecological functions. This study aimed to investigate the temporal and spatial distribution characteristics and driving factors of the community structure of denitrifying bacteria from landscape water. The functional gene nirS was used as a functional marker to explore the community of denitrifying bacteria in the water and sediment of landscape water. Based on parameters of the water and sediment, the temporal and spatial distribution characteristics and driving factors of the community of denitrifying bacteria were studied. The results showed significant seasonal differences in water parameters and spatial differences in sediment nitrogen (P<0.001). No significant difference (P>0.05) was observed in α-diversity; the EC and SOEF-NH4+-N were important factors affecting the α-diversity of the water and sediment. Denitrifying bacteria mainly belonged to the phylum Proteobacteria and the genera Dechloromonas, Rhodocyclaceae, Pseudomonas, Rhodobacter, and Thauera. Principal coordinate analysis revealed that the community of denitrifying bacteria in the water and sediment exhibited significant spatial differences (P<0.001); keystone denitrifying bacteria in the water also exhibited significant spatial differences (P<0.001). RDA and RF analysis showed that the permanganate index and TP were the main environmental factors affecting the total and keystone denitrifying bacteria in the water; SOEF-NH4+-N, IEF-NH4+-N, and WAEF-NO3--N were the main environmental factors affecting the total and keystone denitrifying bacteria in the sediment. These findings could serve as a reference to understand the interaction mechanism between nitrogen and denitrification bacterial communities in landscape water.
Keywords: bioinformatics analysis; high-throughput sequencing; landscape water; nirS; sediment.