为揭示富营养化浅水池塘昼夜性的温室气体通量特征,利用DLT-100温室气体分析仪高采样频率的优势,通过48 h的在线观测,获得了宜昌野猪林池塘夏季CH₄和CO₂扩散和冒泡释放的昼夜性通量数据。观测点F点水气界面总CH₄和CO₂通量分别约为595.2,1 450.8 mg/(m²·d),CH₄和CO₂气泡排放量分别占到总排放量的99.7%和3.0%。观测期内冒泡存在高度时间变异性,最大的一次CH₄冒泡释放速率为424.28 mg/(m²·h),占2 d内总气泡释放量的35.75%,而大多数时段的CH₄冒泡速率低于20.0 mg/(m²·h)。监测期内CH₄和CO₂扩散通量的最高值分别为各自最低值的6.0和6.5倍。监测表明,富营养化浅水池塘夏季CH₄通量非常高,且主要以冒泡方式释放;而CO₂通量明显响应于浮游植物光合作用和呼吸作用交替的新陈代谢作用,存在昼夜性的变化规律。

Methane (CH₄) and Carbon dioxide (CO₂) emission pathways in summer were quantified during a 48 hours online survey of a subtropical shallow pond in Yichang, China. We separated the diel bubble and diffusion gas fluxes measured by the DLT-100 Analyzer (Los Gatos Research, USA) thanks to its high sampling frequency. The total emission fluxes of CH₄ and CO₂ were 595.2 mg/(m²·d) and 1450.8 mg/(m²·d) respectively. Bubble emissions of CH₄ and CO₂ accounted for 99.7% of the total CH₄ emission and only 3.0% of the total CO₂ from the pond. Bubble emissions are highly time-variable in the observation period, with the biggest CH₄ bubbling rate of 424.28 mg/(m²·h), accounting for 35.75% of the two days’ total bubbling CH₄ emissions, but ebullition CH₄ flux was mainly located at <20 mg/(m²·h). The maximums of the diel diffusion CH₄ and CO₂ flux were 6.0 and 6.5 times of the responding minimums respectively.