[Diversity and community characteristics of organic phosphate-mineralizing bacteria in the sea area between Minjiang Estuary to Pingtan.]

Microbial mineralization of organic phosphorus is an important component of marine phosphorus cycle. The research on organic phosphate-mineralizing bacteria (OPB) is helpful to reveal microbial driving mechanism of organic phosphorus mineralization in eutrophic sea area. The diversity and community characteristics of OPB were examined by Illumina high-throughput sequencing using the primer sets phoX in the sea area between Minjiang Estuary to Pingtan in April (spring) and July (summer) 2019. The results showed that the Shannon index of OPB in the surface seawater samples ranged from 3.21 to 7.91, and that the diversity at each station was greater in spring than that in summer. Shannon index of OPB in the sediment samples ranged from 2.04 to 8.70, which was greater in summer than that in spring. Shannon index of OPB in surface seawater of each station was higher than that of sediment in spring, while it was in adverse in summer. Nine phyla of OPB were detected in surface seawater, with Proteobacteria and Cyanobacteria being the most abundant. Tweleve phyla of OPB were detected in the sediments, with Proteobacteria and Bacteroidetes being the most dominant. OPB community composition at the genus level showed obvious spatio-temporal variation. Leisingera,Phaeobacter,Thalassococcus, and Pseudomonas were the major genera in the seawater in spring, while Synechococcus, Halioglobus, Roseovarius, Phaeo-bacter, Sulfitobacter, and Hyphomonas were the major genera detected in summer. Leisingera, Phaeobacter, Vibrio, and Sulfitobacter were major genera in the sediment in spring, while Azospirillum, Aminobacter, Sulfurifustis, Burkholderia, and Thiohalobacter were the major genera in summer. A large number of unclassified OPB were detected in both surface seawater and sediment. The redundancy analysis results showed that dissolved oxygen, water temperature, pH, dissolved inorganic nitrogen, NO2--N, and NO3--N had great influences on community distribution of OPB in the surface seawater. The abundant OPB in the surface seawater and sediment might play an important role in phosphorus cycle in this sea area.