胶州湾和东太平洋海隆(~13°N)沉积物微生物多样性研究

IOCAS-IR > 海洋环流与波动重点实验室

	胶州湾和东太平洋海隆(~13°N)沉积物微生物多样性研究
其他题名	Spatial and temporal variability of the benthic bacterial communities in Jiaozhou Bay,north China, and the vertical distribution of bacterial and archaeal communities along discrete layers of a deep-sea cold sediment sample collected at the East Pacific Rise (~13°N)
	李友训
学位类型	博士
	2008-06-11
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	沉积物微生物多样性分子生物学技术环境因子胶州湾东太平洋海隆
摘要	海洋是一个巨大的生态系统，多样的微生物是构成海洋生态系统的基本元素。海洋微生物的群落结构及演变深刻的反映着海洋生态系统的变迁。本文采用分子生物学技术，研究了近海沉积物生态系统——胶州湾沉积物中细菌的多样性、群落结构的时空演替规律以及远洋深海沉积物生态系统——东太平洋海隆北纬13o附近深海沉积物中细菌和古细菌群落结构沿沉积物断层的分布情况，结果表明在两处沉积物中，微生物群落的结构都与环境因子有显著的相关性，是反映海洋沉积物环境特征的重要（分子）标志物，并且可能在这些环境中参与生物地球化学循环等重要过程。 1.从胶州湾不同区域的8个代表性站点采集4个季度的沉积物样品。提取总基因组DNA，利用16S rDNA作为分子标记，采用克隆文库对胶州湾沉积物中细菌群落的组成、空间分布和季节演替规律进行了研究。结果显示沉积物中的细菌具有高度多样性，来自于13个细菌门，同时还有28%的未鉴定克隆，表明胶州湾沉积物中蕴藏着巨大的微生物资源。其中已鉴定的优势种群是α-、β-、γ-、δ-变形细菌、绿弯菌、厚壁菌、蓝细菌和放线菌。同时还包括酸杆菌、拟杆菌、浮霉菌、疣微菌、芽单胞菌、绿菌、梭杆菌、异常球菌-栖热菌等类群的存在。将各克隆库的组成与温度、总碳、总氮等环境因子结合分析，结果显示细菌群落结构更替的主要驱动力是季节变化所带来的温度等环境因子的演变。对数据库中与本研究所获得序列具有最近亲缘关系序列的来源环境进行分析表明，胶州湾中细菌群落受航运活动、水产养殖、重金属污染等人类活动的明显影响，同时这些活动表现出显著的空间特异性，比如C4和D6等站点明显受到航运活动的影响，而A3和Y1等站点则容易受到沿岸径流所带来的淡水和油污染的影响。 2.分别利用PCR-DGGE和克隆文库技术对东太平洋海隆北纬13o附近深海柱状沉积物样品中细菌和古菌群体进行研究，结果显示这些微生物群落沿四个分别代表不同沉积年代断层明显的成层分布，与环境因子结合分析表明这种成层分布与氧化还原性质等地球化学特征的成层分布相吻合，提示我们该生态系统中的微生物受到环境因子的巨大作用，同时也表明这些微生物可能参与该生态系统中硫、金属元素代谢等过程。通过系统发育分析，四个断层中的微生物群落中呈现出很多与热液活动相关的个体（其中34.7%的细菌序列和31%的古菌序列与来源于各种热液环境的序列具有最近的亲缘关系）。但总体群落结构分析表明该区域可能属于热液活动影响区域的边缘，处于从热液活动环境到普通的低温沉积物环境的过渡区域。 3.将在胶州湾和东太平洋海隆北纬13o附近海洋沉积物生态系统中都存在的优势细菌类群（α-、β-、γ-、δ-变形细菌和放线菌、绿弯菌、厚壁菌、酸杆菌、浮霉菌）进行系统发育分析和背景比较分析，结果显示两处沉积物中的细菌优势种群虽然在大类群上很多是相同的，但是可能由于两处沉积物中不同物理化学等环境因子的选择作用（如胶州湾的近海特征和人为活动，东太平洋深海特点和热液活动），而导致优势种群在系统发育关系上距离比较远。这表明独特的微生物群落结构，特别是优势种群的群落结构信息是描述特定环境生态系统的重要方面。本研究表明在全球环境变迁中,自然环境因子和人类活动都在深刻改变着微生物群落的结构和功能。本文阐述了在环境变迁特定时期两处沉积物生态系统中的微生物群落结构及时空差异，为研究大范围生态系统的演变提供了依据，同时也为在两处沉积物环境中进行微生物参与的生物地球化学研究奠定了基础。
其他摘要	Ocean, a great ecosystem on earth, is a physical organization of diverse of microbes. Therefore, microbial community composition and dynamics play an important role in sustainability of marine ecosystem and can be an indicator of its inhabiting environment. In this paper, molecular techniques were employed to investigate the spatial and temporal variability of the benthic bacterial communities in Jiaozhou Bay, north China, and the vertical distribution of bacterial and archaeal communities along discrete layers of a deep-sea cold sediment sample at the East Pacific Rise (EPR) (~13°N). The results indicated that the microbial community composition and structure in the two sediment ecosystems were both closely related to environmental factors and therefore could be an indicator of the whole ecosystem. In addition, some results also provided evidence that some microbes might play an important role in biogeochemical cycles in these environments. Sediment samples were taken at 8 stations for four seasons from Jiaozhou Bay. Total genomic DNA was extracted from each of the samples and 16S rDNA clone libraries were constructed to investigate the composition and spatial and temporal variability of bacterial communities. The benthic bacterial communities in the sediment of Jiaozhou Bay displayed a diversified composition, including members from 13 bacterial phylum and some unclassified sequences (28%). α-, β-, γ-, δ- proteobacteria, Chloroflexi, Firmicutes, Bacteroidetes, Actinobacteria and Cyanobacteria were the dominant groups and members of Acidobacteria, Planctomycetes， Verrucomicrobia, Gemmatimonadetes, Chlorobi, Fusobacteria and Deinococcus-Thermus were also found in sediment of Jiaozhou Bay. Total community structure exhibited a clear seasonal succession whereas spatial variations were also detected in response to the environmental settings such as total nitrogen and total phosphor content. Comparative phylogenetic analysis of the closest relatives of the sequences obtained in Jiaozhou Bay revealed the presence of influences of human activities such as the influence of harbor, aquaculture and heavy metal contamination, which exhibited spatial and temporal specificities. For example, there were obvious harbor influence at station C4 and D6, whereasA3 and Y1 were more related to fresh water and oil contamination. 16S rDNA based DGGE and clone libraries were used to study the bacterial communities and archaeal communities in the deep-sea cold sediment sample collected at the EPR (~13°N), respectively. Results revealed that both bacterial and archaeal communities displayed a clearly stratified distribution along four discrete layers, which were greatly affected by the vertical zonation of geochemical features. The high percentage of hydrothermal-related members existing in prokaryotic communities (34.7% of the bacterial sequences and 31% of the archaeal sequences) suggested the considerable impact of the hydrothermalism on the surrounding environments, whereas total community analysis indicated this area was a transitional region from the hydrothermal vents to the cold sediment with great biological and ecological importance. Comparison of the dominant bacterial groups inhabited both Jiaozhou Bay and the EPR revealed a considerable difference in phylogeny and the source environments of their closest relatives, indicating the great impact of the total environmental settings of a ecosystem to the microbial community. Therefore, microbial community structure, especially the dominant microbial groups, could be a good indicator of certain ecosystem. The results of the work also indicated that both human activity and the natural environmental factors are forging the composition and function of microbial community. Furthermore, this paper described some useful information for further studies such as the geochemical cycles and global climate change by providing a baseline of the microbial community in the sedimentary environments of Jiaozhou Bay and the EPR (~13°N).
页数	127
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/989
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	李友训. 胶州湾和东太平洋海隆(~13°N)沉积物微生物多样性研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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