|关键词||海岸带 微生物 空间分布 环境因素 地理限制|
通过细菌16S rDNA高通量测序的方法，对南海北部水层及沉积表层细菌群落多样性及空间分布进行了比较分析，并检验了环境因素、地理限制及深度对微生物群落的影响。结果表明，约95%的细菌16S rDNA序列归属于γ-变形菌纲、厚壁菌门、蓝细菌门、α-变形菌纲等优势类群。沉积样本中的优势细菌类群主要与粒度、氮含量等环境参数相关，而水体样本的优势细菌类群与取样深度密切相关。相关性检验结果显示，沉积样本的α-多样性指数与碳含量有着显著的相关关系，而水体样本的α-多样性指数和β-多样性矩阵则显示与取样深度的显著相关。地理距离和海底深度对β-多样性的影响并不显著。
通过高通量测序调查了细菌群落沿渤海至黄海北部梯度的分布。结果表明，细菌群落在海岸梯度下呈现出显著的水平和垂直方向的分布。α-变形菌纲、γ-变形菌纲、拟杆菌门、蓝细菌门等14个浮游细菌优势类群将样本分成3个类别，分别反映了沿海浅水（深度≤ 20 m）、表层水和底层水（沉积物以上2~3 m）的典型生境。每个类别中的判别性类群与空间和环境变量密切相关。环境因素（特别是浊度和亚硝酸盐）对表层细菌多样性有显著影响，而底层水体的群落相似性主要取决于深度。地理距离增加了细菌群落的差异性，并且在表层和底层水中限制了细菌的分布。细菌的扩散也受到磷酸盐的影响，这可能是由于在这个沿海海域的无机氮磷比较高。
|其他摘要||Coastal zone is an important area of biogeochemical process with high biodiversity and biological productivity, and subject to the effects from ocean and land. The dynamic processes dominated by land and sea have created a heterogeneous ecological environment in the coastal zone and also formed multiple biogeochemical environmental gradients. Under these influences, microbial communities always present spatial distribution variation. Analyzing the dominant population and diversity of microbial communities, as well as the relative contribution of environmental factors, geographical distance and depth to microbial biogeography, are important for revealing the mechanism of microbes maintaining biodiversity in the coastal environment. Here we adopted molecular approaches, such as clone libraries and high-throughput sequencing, to explore the spatial distribution and biodiversity of microorganisms in typical coastal waters.|
In this study, ITS1 was used as a DNA marker to assess the biodiversity of eukaryotic plankton in surface waters of Chinese coastal seas. The results of BLAST showed that most ITS1 sequences belonged to six eukaryotic groups, including Metazoa, Fungi and Alveolata. These abundant eukaryotic taxa divided all samples into five distinct clusters, while discriminant taxa in each cluster showed significant spatial distribution variation. In general, α-diversity of eukaryotic community was significantly related to latitude, longitude, water depth, temperature and salinity, presenting an increase trend from north to south. Eukaryotic community dissimilarity (β-diversity) increased with the increasing geographical distance, which indicated a geographical limitation for eukaryotic plankton in Chinese coastal seas. Among the abundant taxa, eukaryotic microorganisms (fungi, dinoflagellates, etc.) may have similar spatial distribution patterns with the other eukaryotic plankton. We therefore propose that coastal zone microbes may have distributional constraints in the coastal zone.
In order to study photosynthetic phytoplankton community in the surface waters of northern South China Sea, we constructed 33 clones using rbcL as a marker gene. The results of BLAST showed that the study area was mainly dominanted by Stramenopiles and Haptophyta, while only five harmful dinoflagellates species were observed. According to α-diversity estimators, community of N709 had very low genetic diversity and richness, which could be explained by the influence of brackish estuarine environment. β-diversity showed all samples could be grouped into three clusters and those samples with approximately the same distance to land clustered together. α-diversity of each sample had significant positive or negative correlation with temperature, depth and latitude. The results of correlation tests showed that distribution of phytoplankton community was mainly determined by temperature, while the influences from geographical distance and other factors were not significant.
Through high-throughput sequencing of bacterial 16S rDNA, we compared and analyzed the diversity and spatial distribution of bacterial communities in water and sediments of northern South China Sea, as well as the effects from environment, depth and geographic distance. The results showed that about 95% of bacterial 16S rDNA sequences belonged to abundant taxa, including Gamma-proteobacteria, Firmicutes, Cyanobacteria, and Alpha-proteobacteria. The dominant bacteria in sediments were mainly related to environmental parameters such as grain size and nitrogen content, while the dominant bacteria in water were related to sampling depth. Correlation tests showed that α-diversity and carbon content in sediments had a significant correlation. Both α- and β-diversity of bacteria in water were significantly associated with sampling depth. However, we did not found bacterial β-diversity was significantly affected by geographic distance and seafloor depth.
We performed high-throughput sequencing to investigate spatial distribution of bacterial communities along the gradients from Bohai Sea to northern Yellow Sea. The results showed bacterial communities presented remarkable horizontal and vertical distribution under coastal gradients. Fourteen abundant taxa, including Alpha-proteobacteria, Gamma-proteobacteria, Bacteroidetes and Cyanobacteria, clustered the samples into three distinctive groups, reflecting typical habitats in shallow coastal water (depth ≤ 20 m), sunlit surface layer and bottom water (at 2~3 m above sediment). Discriminant taxa of each cluster were strongly correlated to spatial and environmental variables. Environmental factors (especially turbidity and nitrite) exhibited significant influences on bacterial β-diversity in surface water, while community similarity in bottom water was mainly determined by depth. Geographic distance enhanced bacterial community dissimilarity and limited bacteria distribution in both surface and bottom water. Bacterial dispersal was also affected by phosphate, which was possible due to the high ratios of N/P in this coastal sea area.
The Laizhou Bay is famous for aquaculture, but has been subject to eutrophication and contamination for years. High concentrations of nutrients from the Xiaoqing River are considered as the main cause for significant eutrophication in the west of Laizhou Bay. Here we present results of the research on sedimentary microbial assemblages along this spatial gradient between riverine and marine environments by high-throughput sequencing. Our results showed that the dominant bacteria included γ-Proteobacteria, Bacteroidetes, δ-Proteobacteria, while the dominant fungal taxa were related to Basidiomycotina, Ascomycota and Chytridiomycota. The predominant phyla/classes of bacteria and fungi clustered the samples into two distinct provinces, while discriminant taxa of each province were strongly associated with spatial factors and environmental factors. Dominant components of bacteria and fungi were regulated by inorganic nitrogen. Spatial variation of bacterial communities was mainly related with the distribution of phosphates, suggesting a phosphate-limitation pattern for the bacterial communities. α- and β-diversity of fungal communities exhibited a significant correlation with water depth. We consider the distinct distributional gradients of bacterial and fungal communities might be due to their functions in the coastal ecosystem.
|于淑贤. 中国典型海岸带海域的微生物梯度分布现象研究[D]. 北京. 中国科学院大学,2017.|