Research On The Diversity Of Denitrifying Bacteria From Sediments Of Bohai Sea

To understand the composition and structure of denitrifying bacterial communities in sedimentary environment of Bohai Sea, the diversity of nitrous oxide reductase gene nosZ from the sediments of Bohai Sea was investigated by using a PCR-based gene cloning approach. A total of 427 nosZ gene clones were obtained from 6 sampling stations. Restriction analysis of cloned nosZ sequences showed a total of 320 Operational Taxonomic Units (OTUs) were obtained from all samples. The number of OTUs in every station was ranged from 41 to 62 in each station, showing high diversity. The levels of identity of the nosZ sequences to their best-match known sequences retrieved from the GenBank database varied from 79% to 100%. Molecular phylogenetic analysis of nosZ sequences retrieved from the sediments or marine aquaculture biofilter of Jiaozhou Bay, Atlantic continental shelf and Rehovot in Israel assigned the nosZ sequences into 5 major clusters(Clusters I-V).Cluster Environment, Jackknife Cluster and Principal Coordinates Analysis (PCoA) indicated that the denitrifying bacterial communities of B003 and B007, B005 and B011 were more similar, respectively; however, B001 and B015 were not. The correlation analysis between geographic locations and its biogeochemical data indicated that multi-environment factors, mainly sediment porewater concentration of NH₄⁺-N and dissolved O₂ content controlled the community structure of denitrifying bacteria. Terrestrial pollution, riverine input and hydrodynamic factors may be the key factors to affect the diversity of denitrifying bacteria in the sedimentary environment of Bohai Sea.