Structure characteristics of core bacterial communities in surface sediments and analysis on their responses to environmental factors in the inlet of Bohai Bay

Abstract:

[Background] In recent years, the increasingly polluted environment of Bohai Bay has impacted the sustainability of offshore ecosystems. [Objective] To explore the distribution characteristics of bacterial communities in surface sediments and their response to environmental factors, we selected surface sediment samples from 21 stations for study. [Methods] We investigated the microbial community structure by sequencing the V3?V4 hypervariable regions of bacterial 16S rRNA gene using the Illumina HiSeq 2500. Bacterial community composition, spatial distribution characteristics and environmental factors were combined and analyzed in an attempt to understand the key interactions. [Results] The 16S rRNA gene clone library analysis indicated that the most common phyla that were widely distributed in the 21 sites were: Proteobacteria (56.8%), Acidobacteria (8.9%), Chloroflexi (8.1%), Bacteroidetes (6.2%). Moreover, γ- Proteobacteria and δ- Proteobacteria were the most dominant classes in Proteobacteria. Total organic carbon and total organic nitrogen content in the near shore sediments is high due to the input of anthropogenic materia and gradually decreased offshore. The most significant influence on species composition and community structure within the study area were found to be from particle size (content<4 μm) and organic nitrogen load. [Conclusion] The microbial diversity in the inlet of Bohai Bay is very high and is significantly related to a variety of environmental parameters. Human activities play an important role in structuring the microbial diversity, community structure and distribution.

Key words:Bohai Bay, Sediment, Microbial community, 16S rRNA gene diversity