引黄对受水河段沉积物微生物群落的影响

人类活动可明显降低地表水体水环境质量,同时对水生态系统产生深刻的影响.本文基于16S rRNA高通量测序技术,研究了引黄调水对汾河受水河段沉积物微生物群落组成、结构和多样性的影响,探讨了引水对沉积物中微生物群落的影响机制.结果表明,黄河水的引入使汇入口处沉积物中微生物群落多样性水平升高,并带来新微生物物种硫杆菌属、厌氧绳菌属和亚硝化单胞菌属,新增菌种不仅在下游逐渐适应环境,而且通过上溯扩张使汇入口上游河段沉积物微生物群落发生改变.引黄间歇期受水河段沉积物微生物群落逐渐恢复,优势菌转化为芽孢杆菌,乳球菌的丰度相应增加,硫杆菌属消失.丛毛单胞菌在汾河受水河段沉积物环境中较为稳定,而硫杆菌、芽孢杆菌和乳球菌容易受到引黄的影响,其主要环境影响因素为水体矿物质含量及沉积物有机质、全氮、碱解氮和全钾.间歇期支流汇入使芽孢杆菌退化,丧失绝对优势地位,而蓝藻大量繁殖成为优势种.引黄期支流汇入后,硫杆菌属和厌氧绳菌属分别成为汇入点下游的优势菌和亚优势菌.

Effects of the Yellow River diversion on microbial communities in sediments of the receiving reach

Human activities can significantly reduce the quality of surface water environment and have profound impacts on water ecosystems. In this paper, the effects of water diverting from the Yellow River on the composition, structure and diversity of microbial communities in sediments of the Fen River are studied based on the 16S rRNA high-throughput sequencing technology. The influence mechanism and the effects of tributaries confluence are discussed. Results show that the injection of the Yellow River water brings new microbial species including Thiobacillus, Nitrosomonadaceae and Anaerolineaceae into sediments of the Fen River elevating the level of microbial community diversity. These new strains gradually adapt to the environment in the downstream, and change microbial communities in sediments of the nearby upstream through the backward expansion. The microbial communities in sediments of the receiving river gradually recover during the intermittent stage, and the dominant bacteria group is transformed into Bacillus. The abundance of Lactococcus increases correspondingly, and Thiobacillus disappears. Comamonadaceae is more stable in sediments of the Fen River, while Thiobacillus, Bacillus and Lactococcus are easily disturbed by the Yellow River water. The major environmental factors are recognized as mineral content of water, soil organic matter (SOM), total nitrogen (TN), alkali-nitrogen (AN) and total kalium (TK). The confluence of tributaries makes Bacillus degradation with the loss of absolute dominance during the injection suspension, while Cyanobacter blooms and becomes one of dominant species. After the injection, Thiobacillus becomes the dominant species in the downstream of the confluence point, and Anaerolineaceae becomes the subdominant species due to the confluence of tributaries.