Yuan Xun-Chao, Wang Min, Guo Xiao-Yu, Wu Dong-Li
College of Resources Environment and Tourism, Capital Normal University, Beijing 100048, China.
Meteorological Observation Center of China Meteorological Administration, Beijing 100081, China.
Huan Jing Ke Xue. 2022 Aug 8;43(8):4097-4107. doi: 10.13227/j.hjkx.202112023.
Planktonic microorganisms play an important role in urban aquatic ecosystems; however, environmental changes significantly affect their role in the degradation and transformation of pollutants. The highly artificial North Canal River was chosen as the research area in this study. Seasonal changes in planktonic microbial community structure were studied using 16S rRNA high-throughput sequencing. The seasonal change mechanism of planktonic microbial diversity in urban rivers supplied with reclaimed water and its response relationship with environmental parameters were examined. The results showed that there were significant seasonal changes in the diversity and structure of the planktonic microbial community. The alpha diversity in summer was significantly higher than that in spring, owing to the enhancement of water diffusion capacity caused by seasonal rainfall and physical disturbance of the reclaimed water supply. The beta diversity of the planktonic microbial community in summer was weakened compared to that in spring, also owing to the enhancement of water diffusion capacity. Seasonal runoff and temperature were the main driving factors of the seasonal variation in hydrology and water quality in the highly artificial urban river. The changes in NO-N and TP caused by seasonal runoff and temperature change were the main reason for planktonic microbial diversity changes in the river. The reductive environment of the river was caused by static and discontinuous flow in the spring. Anaerobic bacteria such as Bacteroidetes related to the degradation of dissolved organic matter and Gracilibacteria related to the denitrification process were dominant in the river. Seasonal runoff and frequent rainfall in summer, as well as the increase in the opening and closing frequency of river sluice gates, enhanced the reoxygenation capacity of the river. This significantly alleviated nutrient pollution in the North River Cannel. Additionally, aerobic bacteria and facultative anaerobic bacteria were dominant species in the river during spring. Cyanobacteria with high temperature characteristics, Chloroflexi and other autotrophic microorganisms, as well as Acidobacteria and Gemmatimonadetes played an important role in the degradation and transformation of pollutants. The results of this study have practical significance for urban river pollution control and ecological restoration with reclaimed water as the recharge water source.
浮游微生物在城市水生生态系统中发挥着重要作用；然而，环境变化会显著影响它们在污染物降解和转化中的作用。本研究选择人工化程度高的北运河作为研究区域。利用16S rRNA高通量测序研究浮游微生物群落结构的季节变化。考察了再生水补给城市河流中浮游微生物多样性的季节变化机制及其与环境参数的响应关系。结果表明，浮游微生物群落的多样性和结构存在显著的季节变化。夏季的α多样性显著高于春季，这是由于季节性降雨和再生水补给带来的物理扰动导致水体扩散能力增强。与春季相比，夏季浮游微生物群落的β多样性也因水体扩散能力增强而减弱。季节性径流和温度是高度人工化城市河流中水文和水质季节变化的主要驱动因素。季节性径流和温度变化引起的NO-N和TP变化是河流中浮游微生物多样性变化的主要原因。春季河流的静态和不连续流动导致了河流的还原环境。与溶解有机物降解相关的拟杆菌属和与反硝化过程相关的纤细杆菌属等厌氧菌在河流中占主导地位。夏季的季节性径流和频繁降雨，以及河闸开闭频率的增加，增强了河流的复氧能力。这显著缓解了北运河的营养污染。此外，春季河流中的优势菌种为需氧菌和兼性厌氧菌。具有高温特征的蓝细菌、绿弯菌门等自养微生物，以及酸杆菌门和芽单胞菌门在污染物的降解和转化中发挥了重要作用。本研究结果对于以再生水为补给水源的城市河流污染控制和生态修复具有实际意义。
