Yang Cheng, Zeng Zhuo, Zhang Han, Gao Dongdong, Wang Yuanyuan, He Guangyi, Liu Ying, Wang Yan, Du Xinyu
Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, China.
Sichuan Academy of Environmental Science, Chengdu, China.
Environ Sci Pollut Res Int. 2022 Dec;29(56):84206-84225. doi: 10.1007/s11356-022-21627-7. Epub 2022 Jul 2.
With rapid urbanization and industrialization, rural rivers in China are facing deterioration in water quality and ecosystem health. Microorganisms living in river sediments are involved in biogeochemical processes, mineralization, and degradation of pollutants. Understanding bacterial community distribution in rural rivers could help evaluate the response of river ecosystems to environmental pollution and understand the river self-purification mechanism. In this study, the relationship between characteristics of sediment microbial communities and the surrounding environmental factors in a typical rural river was analyzed using 16S rRNA gene sequencing technology. The results showed that the dominant bacterial groups in the river sediment were Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, Bacteroidetes, and Firmicutes, accounting for 83.61% of the total microbial load. Different areas have different sources of pollution which give rise to specific dominant bacteria. The upstream part of the river flows through an agricultural cultivation area where the dominant bacteria were norank_f_Gemmatimonadaceae, Haliangium, and Pseudolabrys, possessing obvious nitrogen- and phosphorus-metabolizing activities. The midstream section flows through an urban area where the dominant bacteria were Marmoricola, Nocardioides, Gaiella, Sphingomonas, norank_f_67-14, Subgroup_10, Agromyces, and Lysobacter, with strong metabolizing activity for toxic pollutants. The dominant bacteria in the downstream part were Clostridium_sensu_stricto_1, norank_f__Bacteroidetes_vadinHA17, Candidatus_Competibacter, and Methylocystis. Redundancy analysis and correlation heatmap analysis showed that environmental factors: ammonia nitrogen (NH-N) and total nitrogen (TN) in the sediment, and pH, temperature, TN, electrical conductivity (EC), and total dissolved solids (TDS) in the water, significantly affected the bacterial community in the sediment. The PICRUSt2 functional prediction analysis identified that the main function of bacteria in the sediment was metabolism (77.3%), specifically carbohydrate, amino acid, and energy metabolism. These activities are important for degrading organic matter and removing pollutants from the sediments. The study revealed the influence of organic pollutants derived from human activities on the bacterial community composition in the river sediments. It gave a new insight into the relationship between environmental factors and bacterial community distribution in rural watershed ecosystems, providing a theoretical basis for self-purification and bioremediation of rural rivers.
随着快速的城市化和工业化进程，中国农村河流面临着水质恶化和生态系统健康受损的问题。生活在河流沉积物中的微生物参与生物地球化学过程、矿化作用以及污染物的降解。了解农村河流中细菌群落的分布有助于评估河流生态系统对环境污染的响应，并理解河流的自我净化机制。在本研究中，利用16S rRNA基因测序技术分析了一条典型农村河流沉积物微生物群落特征与周围环境因素之间的关系。结果表明，河流沉积物中的优势细菌类群为变形菌门、放线菌门、绿弯菌门、酸杆菌门、拟杆菌门和厚壁菌门，占微生物总量的83.61%。不同区域有不同的污染源，从而产生特定的优势细菌。河流上游流经农业种植区，优势细菌为未分类的芽单胞菌科、盐土单胞菌属和假拉布氏菌属，具有明显的氮磷代谢活性。中游流经城市区域，优势细菌为嗜石菌属、诺卡氏菌属、盖氏菌属、鞘氨醇单胞菌属、未分类的f_67 - 14、亚群10、土壤杆菌属和溶杆菌属，对有毒污染物具有较强的代谢活性。下游的优势细菌为严格梭菌属1、未分类的f__拟杆菌vadinHA17、候选竞争杆菌属和甲基孢囊菌属。冗余分析和相关热图分析表明，环境因素：沉积物中的氨氮（NH-N）和总氮（TN），以及水体中的pH值、温度、TN、电导率（EC）和总溶解固体（TDS），对沉积物中的细菌群落有显著影响。PICRUSt2功能预测分析确定沉积物中细菌的主要功能是代谢（77.3%），特别是碳水化合物、氨基酸和能量代谢。这些活动对于降解有机物和从沉积物中去除污染物很重要。该研究揭示了人类活动产生的有机污染物对河流沉积物中细菌群落组成的影响。它为农村流域生态系统中环境因素与细菌群落分布之间的关系提供了新的见解，为农村河流的自我净化和生物修复提供了理论依据。
