西藏尼洋河沉积物中微生物群落结构特征分析

尼洋河是雅鲁藏布江的重要支流,是西藏工布和林芝地区的重要水源地.本研究分析了尼洋河水体理化指标、 12种金属含量和沉积物微生物群落结构特征.结果表明, 2017年和2018年沉积物微生物群落在门水平的结构基本相同,属水平结构相似.变形菌门是尼洋河沉积物的第一优势菌门,其他优势菌门有拟杆菌门、酸杆菌门和放线菌门等;属水平上黄杆菌属丰度较高,气单胞菌属等条件致病菌菌属可被检出;聚类分析发现尼洋河沉积物微生物群落在空间上存在一定的差异性,上游、中游和下游不同河段微生物群落之间差异显著,电站库区沉积物微生物群落具有特异性.相关性分析表明,温度、溶解氧、电导率和铬、锌、锶和钡等金属含量与尼洋河沉积物门水平特定微生物丰度存在显著相关关系.冗余分析表明,总氮、总磷、溶解氧、铬、锶、钡和锰等是尼洋河沉积物中微生物群落结构的主要影响因子.本研究结果可为认识尼洋河沉积物中微生物群落的时空变化特征,识别环境影响因子提供了数据支撑.

Structural Characteristics of Microbial Communities in the Sediments of the Niyang River in Tibet

The Niyang River is an important tributary of the Yarlong Zangbo River, which is also an important water source in the Gongbujiangda and Linzhi areas of Tibet. In this study, water and sediment samples from 18 sites in the Niyang River were collected. The physical and chemical properties, concentrations of 12 heavy metals, and the microbial community in the sediments were determined. The microbial community structures in the sediments collected in 2017 and 2018 were highly similar at the phylum and genus levels. The most dominant type of bacteria in the sediment of the Niyang River was Proteobacteria. Other dominant bacteria included Bacteroidetes, Acidbacteria, and Actinobacteria. At the genus level, the abundance of Flavobacterium was high. Other conditional pathogenic bacteria, such as Aeromonas and Acinetobacter, were detected. Cluster analysis found that there were certain spatial differences among the upstream, midstream, and downstream microbial communities. The microbial community of sediments in the power station reservoir area was unique. Correlation analysis showed that the temperature, dissolved oxygen, electrical conductance, Cr, Zn, Sr, and Ba in the sediments had high correlation with abundance of specific microbes at the phylum level. Redundancy analysis suggested that total nitrogen, total phosphorus, dissolved oxygen, Cr, Sr, Ba, and Mn were the main influencing factors of microbial community structure in the sediments of the Niyang River. The results of this study provide data support for understanding the spatial and temporal distribution of the microbial community in sediments of the Niyang River and identifying their environmental impact factors.