Patterns and drivers of CH_(4) concentration and diffusive flux from a temperate river–reservoir system in North China  

作　　者：Fanyan Yang Jicheng Zhong Shaoming Wang Xiaokang Hu Hongwei Wang Mengyao Tang Min Zhang Chuanzhe Sun Lei Zhang 

机构地区：[1]State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China [2]College of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,China [3]Bureau of Luanhe Diversion Project,Haihe Water Conservancy Commission,Ministry of Water Resources,Qianxi 064309,China [4]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Journal of Environmental Sciences》2022年第6期184-197,共14页环境科学学报（英文版）

基　　金：supported by the National Nature Science Foundation of China(Nos.41771516,41771122);the Bureau of Luanhe Diversion Project of the Haihe River Water Conservancy Commission,Ministry of Water Resources of China and Tianjin Water Affairs Bureau project(Nos.HYGP-2019-C-130,TJGC-2019-C-060)。

摘　　要：Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the estimation of the global CH_(4) budget. In this study, surface water CH_(4) concentrations were measured and diffusive CH_(4) fluxes were estimated via a thin boundary layer model in a temperate river–reservoir system in North China, using spatial(33 sites) and temporal(four seasons) monitoring;the system has experienced intensive aquaculture disturbance. Our results indicated that the dissolved CH_(4) concentration in the reservoir ranged from 0.07 to 0.58 μmol/L, with an annual average of 0.13 ± 0.10 μmol/L, and the diffusive CH_(4) flux across the water–air interface ranged from 0.66 to 3.61 μmol/(m^(2)·hr),with an annual average of 1.67 ± 0.75 μmol/(m^(2)·hr). During the study period, the dissolved CH_(4) concentration was supersaturated and was a net source of atmospheric CH_(4) . Notably,CH_(4) concentration and diffusive flux portrayed large temporal and spatial heterogeneity.The river inflow zone was determined to be a hotspot for CH_(4) emissions, and its flux was significantly higher than that of the tributary and main basin;the CH_(4) flux in autumn was greater than that in other seasons. We also deduced that the CH_(4) concentration/diffusive flux was co-regulated mainly by water temperature, water depth, and water productivity(Chla, trophic status). Our results highlight the importance of considering the spatiotemporal variability of diffusive CH_(4) flux from temperate reservoirs to estimate the CH_(4) budget at regional and global scales.

关 键 词：River–reservoir system Greenhouse gas Methane(CH_(4)) Temperate zone Diffusive flux 

分 类 号：X143[环境科学与工程—环境科学]