湖、库水体CH4冒泡排放研究进展

冒泡排放是湖、库水体CH₄排放的主要方式之一,其排放通量和占CH₄总排放量比例均具有极其显著的时空差异性,是当前水体CH₄排放估算不确定性的主要来源之一。然而,目前关于湖、库水体CH₄冒泡排放通量监测、时空分布规律、过程机制和模型模拟的系统梳理鲜有报道。本研究对比了目前水体CH₄冒泡的监测方法技术的适用性及优缺点,分析总结湖、库水体CH₄冒泡排放及通量的时空分布特征,梳理CH₄气泡在沉积物-水体中的产生-成长-迁移-释放的过程、影响因素及模型,并提出了水体CH₄冒泡过程模型框架。最后,本研究提出未来研究应基于湖、库水体分类、设备开发和改进来构建适应性的湖、库水体CH₄冒泡排放监测标准体系,开发基于过程的CH₄冒泡机理模型,为认识变化环境下湖、库水体CH₄冒泡过程和准确估算CH₄排放量提供支撑。

Methane ebullition from lakes and reservoirs: A review

Ebullition is an important pathway for methane (CH₄) emission from lakes and reservoirs. It is a main cause of uncertainty in estimating CH₄ emission owing to the large spatiotemporal variabilities of ebullition. However, a systematic synthesis on CH₄ ebullition monitoring methods, spatiotemporal variabilities, bubble release mechanisms and model simulations is currently lacking. This study summarizes the popular monitoring methods, the spatiotemporal characteristics of CH₄ ebullitive flux from lakes and reservoirs, the processes of CH₄ bubble growth and release in sediment-water continuum, the impact factors and available models. In the end, a conceptional scheme for future model development is proposed. To reduce uncertainties in estimating CH₄ fluxes from lakes and reservoirs under changing environment, an adaptive monitoring strategy should be adopted. This includes classifying lakes and reservoirs according to their respective physiochemical properties and upgrading the measurement devices. Moreover, development of process-based CH₄ ebullition models is urgently needed.