衬砌对河道底泥细菌群落同质化的影响

以高度人工化的再生水补给河道—北运河京津冀流域为研究区，对具有不同河道生境类型的上游与中下游底泥中的细菌群落多样性、组成及环境选择模式进行对比分析.结果表明：中下游河道衬砌工程促进底泥生境特征同质化，进而导致中下游底泥细菌群落同质化.上游细菌群落空间周转率（0.0002）相比较，中下游群落具有较低的空间周转率（0.00002），并在排序图上呈现更紧凑的分布特点.与上游自然生境条件下的群落组成相比较，由于衬砌条件下非优势组分的片段类型多样性较高，优势组分的片段类型多样性及相对丰度较低，最终使得同质化群落表现为较低的丰富度.RDA模型（P=0.002）分析表明，衬砌和TP是影响细菌群落空间变化的主导环境因素，而大环内酯类和四环素类抗生素则对群落结构类内变异起作用.纤维杆菌门（Fibrobacteres）、纤细菌门（Gracilibacteria）、酸杆菌门（Acidobacteria）、Acetothermia的片段类型多样性和费希尔菌门（Fischerbacteria）、Kiritimatiellaeota、放线菌门（Actinobacteria）、蓝细菌门（Cyanobacteria）的相对丰度均与衬砌高度相关.

Lining promotes the homogenization of bacterial communities in sediments

Taking the North Canal in Beijing-Tianjin-Hebei Basin as research area., a comparative analysis of bacterial community diversity, composition and pattern of environmental factors between the upstream and the mid-down stream samples was carried out. The results showed that engineering projects of bottom and bank in the mid-down stream of the North Canal of Beijing-Tianjin-Hebei Basin promoted the homogeneity of the bacterial community. Comparing to the spatial scaling patterns of upstream samples (0.0002), the value of bacterial communities in the mid-down stream (0.00002) was significantly lower and the distribution pattern of samples in the NMDS plot was more intensive. The homogenized community in the mid-down stream showed the lower richness due to the higher fragment type of the non-abundant species, lower fragment type and lower relative abundance of the abundant species. The analysis of RDA model (P=0.002) showed that the engineering projects, the total phosphorus and the antibiotics of macrolide and tetracycline were the key environmental factors. Engineering projects of bottom and bank was closely related to the diversity of Fibrobacteres, Gracilibacteria, Acidobacteria, Acidothermia and the relative abundance of Fischerbacteria, Kiritimatiellaeota, Actinobacteria, Cyanobacteria.