Ponds are increasingly recognized as significant sources of greenhouse gases (GHGs) emitted to the atmosphere. Concomitant with increasing urbanization, more urban ponds are created, many with the aim of buffering peak runoff and improving water quality in downstream waterbodies. However, the impact of urban ponds on GHG emissions is poorly elucidated. In this study, we measured the dissolved concentrations of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) 4 times over a year in 37 ponds located in the city of Silkeborg, Denmark. The results show that the ponds generally acted as a source of GHG with CO₂-C concentrations (standard deviation) of 1938 (2208) µg L⁻¹, CH₄-C of 44 (198) µg L⁻¹, and N₂O-N of 0.8 (1.8) µg L⁻¹. Boosted regression tree models show that vegetation cover, water temperature, and nitrate concentration were the main drivers of CO₂, CH₄, and N₂O concentrations, respectively. Upscaling of the results to the Danish national level showed that urban ponds emit about 38 × 10⁹ g CO₂-equivalents per year, suggesting that urban ponds are significant sources of GHG in urban landscapes.

池塘越来越被认为是排放到大气中的重要温室气体（GHG）的来源。随着城市化程度的提高，创建了更多的城市池塘，许多目的是缓冲高峰径流并改善下游水体的水质。但是，人们对城市池塘对温室气体排放的影响了解得很少。在这项研究中，我们在位于丹麦希尔克堡市的37个池塘中，一年四次测量了二氧化碳（CO ₂），甲烷（CH ₄）和一氧化二氮（N ₂ O）的溶解浓度。结果表明，这些池塘通常是温室气体的来源，CO ₂ -C浓度（标准偏差）为1938（2208）µg L ^-1，CH ₄-C为44（198）µg L ^-1，N ₂ O-N为0.8（1.8）µg L ^-1。增强回归树模型表明，植被覆盖度，水温和硝酸盐浓度分别是CO ₂，CH ₄和N ₂ O浓度的主要驱动因素。将结果升级到丹麦国家水平后，表明城市池塘每年排放约38×10 ⁹  g CO _2-当量，这表明城市池塘是城市景观中重要的GHG来源。