实施生态工程对宁夏第二排水沟水体水质及细菌群落结构的影响

Effects of ecological engineering on water quality and bacterial community structure in the Second Drainage Ditch in Ningxia

摘要:

目的 以宁夏第二排水沟为研究对象，探究实施生态工程后排水沟水体细菌群落结构特征的变化。方法 利用高通量测序技术分析水体样本中细菌群落结构，结合非度量多维尺度分析方法(non-metric multidimensional scaling, NMDS)和冗余分析(redundancy analysis, RDA)，探讨细菌群落的共存模式及其影响因素。结果 生态工程实施后，水体中的铵态氮、总氮、高锰酸盐指数、重铬酸盐指数和氟化物含量在2021年8月至2022年8月期间呈明显下降趋势；水体细菌群落的主要优势菌门为变形菌门、放线菌门、拟杆菌门和绿屈挠菌门，优势菌属主要为hgcI_clade、SAR11_cladeIII、栖湖菌属(Limnohabitans)、红育菌属(Rhodoferax)和黄杆菌属(Flavobacterium)。不同采样点间的群落结构差异显著。NMDS分析表明不同月份之间的差异显著；RDA分析表明总磷(TP)、重铬酸盐指数(COD_Cr)和pH是影响细菌群落结构的主要因子。TP、COD_Cr和总氮(TN)共同对细菌群落结构的解释度最大(8.81%)，其次是TP和COD_Cr共同对细菌群落结构的解释度(-8.05%)。结论 实施生态工程后，宁夏第二排水沟的水质得到了改善，细菌群落结构更加丰富。水质理化特性在驱动宁夏第二排水沟细菌群落分布及多样性方面起到了重要作用，为区域水体生态环境治理提供了科学依据。

关键词:第二排水沟;水体细菌;生态工程;群落结构特征

Abstract:

Objective To study changes of the bacterial community structure in the Second Drainage Ditch in Ningxia after ecological engineering.Methods We employed high-throughput sequencing to study the bacterial community structures in water samples. We explored the factors affecting the bacterial community structure by non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA).Results From August 2021 to August 2022, the ammonium nitrogen, total nitrogen (TN), permanganate index, dichromate oxidizability (COD_Cr), and fluoride in the water decreased substantially after the ecological engineering. The dominant bacterial phyla in the water were Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi and the dominant genera included hgcI_clade, SAR11_cladeIII, Limnohabitans, Rhodoferax, and Flavobacterium. The bacterial community structures showed significant differences across different sampling locations. The NMDS results revealed significant variations in the bacterial community structure across different sampling months. The RDA results indicated that total phosphorus (TP), COD_Cr, and pH were the key factors influencing the bacterial community structure. Notably, TP, COD_Cr, and TN together explained the largest variance (8.81%) in the bacterial community structure, followed by TP combined with COD_Cr (-8.05%).Conclusion After ecological engineering, the water quality of the Second Drainage Ditch improved, and the bacterial community structure became more diverse. The physicochemical properties of the water strongly influence the distribution and diversity of bacterial communities in the Second Drainage Ditch in Ningxia, which provide a scientific basis for managing the regional water environment.

Key words:Second Drainage Ditch;bacteria in water;ecological engineering;community structure characteristics