Emission characteristics and influencing factors of greenhouse gas emissions from urban rivers in the Plain River Network region of China

Climate change has emerged as a global focus, and the emission of greenhouse gases (GHG) exerts a crucial influence on global climate change. The patterns and controls of GHG emissions in urban rivers remain unclear. GHG fluxes in different types of urban river in Changzhou city of China were calculated respectively by the floating static chamber method and boundary layer equation method. Ultraviolet-visible (UV-vis) absorption spectrum and three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) were employed to explore the sources and characteristics of dissolved organic matter (DOM) in rivers. The physical and chemical indicators of river and sediment were monitored on-site and analyzed in the laboratory. Also, the species and quantity of bacteria in the sediment were determined. The Spearman correlation analysis was utilized to identify the key factors influencing GHG emission. The results indicated that, (1) the intensity of sunlight has an effect on the activity of pseudomonas, and thus affects N2O flux; (2) the CO2 flux measured by two methods showed a significant difference and negative correlation (p

气候变化已成为全球关注的焦点，温室气体（GHG）排放对全球气候变化具有至关重要的影响。当前城市河流温室气体排放的规律与调控机制仍不明确。本研究以中国常州市不同类型城市河流为对象，分别采用浮置静态箱法与边界层方程法计算其温室气体通量。通过紫外-可见（UV-vis）吸收光谱与三维激发发射矩阵荧光光谱（3D-EEM）技术，探究河流中溶解性有机质（DOM）的来源与组成特征。对河流水体与沉积物的理化指标开展现场监测，并于实验室进行后续分析。同时测定沉积物中细菌的群落组成与丰度。采用斯皮尔曼相关性分析（Spearman correlation analysis），筛选影响温室气体排放的关键调控因子。研究结果表明：(1) 光照强度可影响假单胞菌属（Pseudomonas）的活性，进而对一氧化二氮（N₂O）通量产生作用；(2) 两种方法测得的二氧化碳（CO₂）通量存在显著差异且呈负相关关系（p