Yin Jie, Chen Xiaobing, Xie Wenting, Wen Lizhen
The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, 210098, China.
College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, 210098, China.
Environ Monit Assess. 2025 Apr 17;197(5):561. doi: 10.1007/s10661-025-14019-0.
Urban lakes contribute to global greenhouse gas (GHG) emissions driven by both natural processes and anthropogenic activities. In this study, we conducted seasonal sampling and analysis of GHG concentrations and water chemistries in Xuanwu Lake, Nanjing, China. Concurrently, we observed pore water chemistry within the lake bottom sediments. Radon isotope activity in lake water was also measured. Then, this study expanded to a broad understanding of urban lake GHG emissions by conducting a meta-analysis of over 100 lakes of similar size but various types (urban vs. non-urban). Xuanwu Lake is a net source of GHG, with mean annual diffusive fluxes of 10.2 ± 9.3 mmol∙m∙d for CO, 3.1 ± 0.3 mmol∙m∙d for CH, and 12.4 ± 1.0 μmol∙m∙d for NO. The lake emitted 614.9 tons of CO, 68.6 tons of CH, and 0.84 tons of NO throughout the year. CO levels were positively correlated with dissolved organic and inorganic carbon, while CH peaked in winter due to increased anaerobic decomposition. NO concentrations were strongly linked to nutrient levels. Furthermore, statistical analysis showed that urban lakes demonstrated significantly greater CH and NO emissions compared to non-urban lakes. These findings emphasize the need for further research and targeted mitigation strategies to address GHG emissions from urban lakes, especially in the context of increasing anthropogenic pressures and climate change.
城市湖泊会因自然过程和人为活动导致全球温室气体（GHG）排放。在本研究中，我们对中国南京玄武湖的温室气体浓度和水体化学性质进行了季节性采样与分析。同时，我们观测了湖底沉积物中的孔隙水化学性质。还测量了湖水中的氡同位素活性。然后，通过对100多个大小相似但类型各异（城市湖泊与非城市湖泊）的湖泊进行荟萃分析，本研究对城市湖泊的温室气体排放有了更广泛的认识。玄武湖是温室气体的净排放源，CO的年均扩散通量为10.2±9.3 mmol∙m∙d，CH为3.1±0.3 mmol∙m∙d，NO为12.4±1.0 μmol∙m∙d。该湖全年排放614.9吨CO、68.6吨CH和0.84吨NO。CO水平与溶解有机碳和无机碳呈正相关，而CH在冬季因厌氧分解增加而达到峰值。NO浓度与营养水平密切相关。此外，统计分析表明，与非城市湖泊相比，城市湖泊的CH和NO排放量显著更高。这些发现强调了需要进一步研究并制定针对性的缓解策略，以应对城市湖泊的温室气体排放，特别是在人为压力不断增加和气候变化的背景下。
