|南海海洋动力过程影响下的细菌群落结构特征; Characteristics of bacterial communities associated with the oceanic dynamics in the South China Sea|
|Abstract||海洋是地球上最大、最古老的生境，面积约占地球表面积71%的海洋由复杂多样的生境构成。海洋中蕴藏着丰富的微生物，这些微生物是海洋物质能量运输过程的中心成员，在生物地球化学循环中起着关键性作用。海洋微生物能对理化环境因子变化做出响应，研究这些响应机制能够帮助了解微生物群落变化与环境条件的相互关系，更有助于对受微生物调节的生物地球化学循环变化的理解。南海作为西太平洋地区最大的边缘海，具有复杂的物理化学环境，从而使南海海域生态系统具有丰富的生物多样性，因而对南海海域展开海洋动力过程影响下细菌群落特征的研究具有重要生态学意义。 本论文对南海跨海盆尺度的微生物群落和功能分布进行研究。搭载2012年10月的基金委南海北部综合航次，采集了南海14°N横断面的11个站位的4个层面（5，25，75和200 m）的43份样品（站位8的200 m样品缺失）。提取43份海水样品的环境总DNA后，利用高通量454焦磷酸测序技术，对16S rRNA基因的高可变区V1－V3进行测序，得到高质量的有效序列802 618条，定义出7 146个有效OTUs。经过生物信息学和统计学分析，发现在南海上层水体中细菌多样性和丰富度随着深度增加而增加，细菌群落组成和功能基因都具有根据采样深度分布的层化特征。此外，东-西向环境差异在75 m对细菌群落形成了显著性影响。除了深度和季风驱动的环流，磷酸盐浓度和盐度对细菌群落的影响显著。本论文首次从海盆尺度展示了复杂理化环境驱动的南海上层水体中浮游细菌的分布特征。|
|Other Abstract||The ocean, the largest and most ancient ecosystem on the earth, which covers about 71% of the Earth’s surface, is composed of complex and diverse habitats. There are abundant microorganisms in the ocean. Marine microorganisms are the central members involved in fluxes of energy and matter in the sea and play a fundamental role in biogeochemical cycles. They respond to variations in the physical and chemical environmental factors. Research on these responses could provide a glimpse of the correlation between the variation in microbial community compositions and environmental conditions, and may develop an understanding of changes in biogeochemical cycles mediated by microbial communities. The South China Sea (SCS), the largest marginal sea in the western tropical Pacific Ocean, is charaterized with complex physicochemical environments, and therefore possesses abundant biological diversity. Discussing the characteristics of bacterial community structure in the context of ocean dynamics in the SCS is ecologically significant. In this study, we tried to unfold the variability in the bacterioplankton community and functional distribution at the basin-scale in the SCS. During the cruise in the northern SCS in October, 2012, sampling was conducted, respectively, at the 5 m, 25 m, 75 m and 200 m depths from a total of 11 stations except the 200 m layer at station 8 along the 14°N transect. All forty-three seawater samples were analyzed through pyrosequencing the hypervariable V1–V3 regions of the 16S rRNA gene. The pyrosequencing produced a total of 802 618 quality-filtered valid reads, and then these sequences were clustered into 7 146 OTUs at a 3% dissimilarity level. Through bioinformatics and statistical analysis, the results revealed that bacterial richness and diversity vertically increased with depth in the epipelagic layer. Further, the stratification was obviously characterized through clustering of the bacterial community compositions and functional genes according to the sampling water-depths. Moreover, the differential environments in the eastern and western SCS influenced the bacterial communities, especially at the 75m layer. Besides vertical depth and water currents driven by monsoon, heterogeneity in the concentrations of phosphate and salinity contributed significantly to the variance in bacterial community. This study firstly showed the epipelagic bacterioplankton variability driven by the physicochemical environment at basin-scale in the SCS.|
张益. 南海海洋动力过程影响下的细菌群落结构特征, Characteristics of bacterial communities associated with the oceanic dynamics in the South China Sea[D],2016.
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