渤海三湾表层水域细菌群落结构多样性及其环境因子分析

Diversity of bacterial community structure and its driving factors in three bays of Bohai Sea

【背景】近海生态系统的可持续发展是目前人们关注的重大问题之一,河口输出以及人类活动干扰对渤海近岸环境有着重要的影响。【目的】选取2015年夏季渤海湾、辽东湾、莱州湾3个断面12个站位表层水样品,探究渤海三湾细菌群落结构多样性。【方法】提取3个断面水环境样品DNA,利用Illumina Hi Seq高通量测序技术对样品进行测序分析,比较3个断面的细菌群落结构多样性差异。【结果】根据多样性指数和稀释曲线结果发现,3个断面的微生物多样性有着明显的差别,多样性依次为莱州湾>渤海湾>辽东湾。分析3个断面中占优势地位的主要类群,渤海湾断面中变形杆菌门(Proteobacteria)所占比例为39.8%,拟杆菌门(Bacteroidetes)占25.7%,蓝细菌门(Cyanobacteria)占22.4%,放线菌门(Actinobacteria)占5.85%,浮霉菌门(Planctomycetes)占4.38%;辽东湾断面各类群所占比例依次为变形杆菌门(Proteobacteria)37.8%,拟杆菌门(Bacteroidetes) 25.7%,蓝细菌门(Cyanobacteria) 17.8%,放线菌门(Actinobacteria) 10.4%,浮霉菌门(Planctomycetes)5.64%;莱州湾断面主要类群所占比例为(Proteobacteria)59.0%,拟杆菌门(Bacteroidetes)17.5%,蓝细菌门(Cyanobacteria)8.2%,放线菌门(Actinobacteria)7.88%。通过主成分分析和热图相关性分析发现环境因子对微生物群落组成和多样性分布有显著的影响,通过Manteltest统计分析,其中硝酸盐的作用尤为显著。【结论】渤海三湾微生物多样性非常丰富且存在较大的差异,莱州湾种群结构最复杂且物种最丰富,渤海湾和辽东湾次之,多样性分布与环境因子和空间分布有一定的相关性,该研究将为进一步保护海洋微生物多样性和生态开发提供一定的理论基础。

[Background] Sustainable development of coastal ecosystem has become one of the most important concerns for people nowadays. Riverine output and anthropogenic interrupt have important impacts on the coastal environment. [Objective] In this study, we collected 12 samples from three transects including Bohai Bay, Liaodong Bay and Laizhou Bay to explore the microbial community and diversity in summer of 2015. [Methods] DNA was extracted from water samples by using DNA extraction kit. Samples were analyzed by Illumina HiSeq sequencing technology. We compared the differences among these three transects according to the analysis results. [Results] The diversity index and rarefaction curves showed significant differences among these three transects. The order of diversity value was Laizhou Bay〉Bohai Bay〉Liaodong Bay. The distribution of the dominant community was as follows： the proportion of Proteobacteria, Bacteroidetes, Cyanobacteria, Actinobacteria and Planctomycetes in the Bohai Bay was 39.8%, 25.7%, 22.4%, 5.85% and 4.38%, respectively. The dominant community proportion in Liaodong bay was Proteobacteria （37.8%）, Bacteroidetes （25.7%）, Cyanobacteria （17.8%）, Actinobacteria （10.4%） and Planctomycetes （5.64%）. While in Laizhou Bay there were only four dominant communities as follows： Proteobacteria （59.0%）, Bacteroidetes （17.5%）, Cyanobacteria （8.2%）, Actinobacteria （7.88%）. By using the principal component analysis （PCA） and Heatmap correlation analysis, we found that environmental factors were key roles in controlling the microbial diversity in the Bohai Sea. Among them, the concentration of nitrate was particularly significant according to the Mantel test analysis. [Conclusion] The microbial diversity in the three bays of Bohai Sea was very rich and multifarious. The population structure and species in the Laizhou Bay is the most complex and abundant among these three bays, and then it is Bohai Bay and Liaodong Bay. There was a significant correlation among microbial diversity, environmental factors and the spatial distribution. Above all, this study will provide a theoretical basis for further protection and ecological development of Bohai Sea.