Rivers are important sources of greenhouse gas emissions in inland waters of terrestrial ecosystems.In recent years,the emission of greenhouse gases has increased the seriousness of environmental problems.This paper focuses on the Sichuan section of the Jialing River as the research subject to explore the spatial distribution characteristics of dissolved CH4 and CO2 concentrations and emission fluxes,and the response of the water physical and chemical properties and land use types to greenhouse gas emissions.Surface water samples were collected from the Jialing River in October 2021,and a modified headspace method was used to capture dissolved CH4 and CO2 in the water.Results indicate that human activities dominate the changes in water quality in the Sichuan section of the Jialing River,with urban and agricultural activities be-ing the primary reasons for the accumulation of nitrogen and phosphorus along the river.The concentrations of CH4 and CO2 in the surface water were(16.87±15.55)nmol·L-1 and(836.11±132.68)μmol·L-1,respectively.The emission fluxes of CH4 and CO2 were(68.39±81.26)nmol·m-2·d-1 and(1 596.08±1 291.61)μmol·m-2·d-1,respectively.The concentration and emission fluxes of CH4 and CO2 exhibited significant spatial heterogeneity.Among the different land use types,the river reach dominated by cultivated land received significant amounts of non-point source pol-lution and terrigenous carbon.The input of these pollutants changed the physical and chemical properties of water bodies,the growth of aquatic plants and phytoplankton,and the microbial activities in the river,and further influenced the produc-tion and release of CH4 and CO2.TN,PO43--P,and area proportion of cultivated land are the key factors contributing to greenhouse gas emissions in the Sichuan section of the Jialing River,which indicating that Greenhouse gas emissions are not only influenced by the ecological environment of the river but also by human activities under different land use types.
关键词
嘉陵江/温室气体/CH4/Co2/通量/空间分布
Key words
Jialing River/greenhouse gas/CH4/CO2/flux/spatial distribution
万方数据