Characteristics of bacterial population of water from Tianjin Lingang Coastal Wetland Park

To understand the bacterial community and its difference characteristics of water bodies in different functional areas of Tianjin Lingang Coastal Wetland Park in different seasons, the high-throughput sequencing technology was used to analyze the bacterial population structure of water from the intake, subsurface wetland, landscape water area and the water outlet of the wetland park in summer and autumn, and the principal component analysis was used to analyze its main environmental influential factors. The results showed that Shannon diversity index of bacteria ranged from 4.25 to 5.14 in summer and from 3.07 to 4.32 in autumn, Chao index of population abundance ranged from 569.10 to 894.04 in summer and from 473.22 to 995.81 in autumn. Overall, Shannon diversity index was higher in summer than that in autumn. And the highest bacterial diversity and richness in summer was in subsurface wetland, while in autumn it was in water intake. A total of 34 phyla, 423 genera, and 641 species of bacteria were detected in summer. The main dominant phyla included Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and the main dominant genera included Rhodobacter, Hydrogenophaga, norank_f_FamilyⅠ. In comparison, a total of 34 phyla, 520 genera, and 786 species of bacteria were detected in autumn. The main dominant phyla included Proteobacteria, Actinomycetes, Actinobacteria, Bacteroidetes, and the main dominant genera includedRhodobacter, Psychrobacter, Synechococcus. Among the dominant genera, the relative abundance of Hydrogenophaga was high only in the subsurface wetland in summer, and that of Psychrobacter was high only in the subsurface wetland in autumn. However, they were not detected in other area, indicating that these genera were unique in the subsurface wetland. The Venn map of species based on OTU levels showed that there were 187 common species in different areas of the wetland park in summer, and 110 species in autumn. The principal component analysis based on OTU level between species composition and environmental factors showed that the main environmental factors affecting the bacterial population composition of wetland parks included temperature, pH, NO_3^--N, and NH₃-N.