Bacterial community structure and its regulating factors in the intertidal sediment along the Liaodong Bay of Bohai Sea, China.

Investigating the entire species composition of the microorganisms is crucial to understand their roles in the biogeochemical cycles. Metagenomic DNA was extracted from six intertidal sediment samples along the Liaodong Bay of Bohai Sea, China, and was sequenced which yielded a total of 64,496 high-quality sequences from 83,485 reads, with an average read length of 463 bp. The sequences were assigned to 20,718 operational taxonomic units (OTUs) which belong to 42 phyla, 90 classes and 376 genera. At the different taxonomic levels, both the dominants and their abundances varied significantly among the six sites. Phylum Proteobacteria predominated in all the six samples, however, not only the abundance of this phylum varied significantly but also the proportions of Alpha-, Beta-, Gamma-, and delta- and epsilon-Proteobacteria varied greatly. The site sediment median grain size and dissolved oxygen (DO) revealed to be key factors regulating the observed significant differences in the bacterial community between sampling sites. In addition, the bacterial composition might be more sensitive than the richness and diversity to the studied environmental conditions.