[Greenhouse Gas Fluxes at Water-Air Interface in Small Pond Using Flux-Gradient Method Based on Spectrum Analyzer]

As an important part of inland waters,small pond is a neglected source of greenhouse gas.The main objective of the study was to quantify greenhouse gas fluxes (CO₂ and CH₄) from small pond in the Yangtze Delta using flux-gradient method.The results showed that:① zero-gradient test indicated that the flux measurement precision for water vapor,CO₂,and CH₄ was 7.525 W·m^-2,0.022 mg·(m²·s)^-1,and 0.054 μg·(m²·s)^-1,respectively.During the test period,84%,80%,and 94% of half-hourly flux data for H₂O,CO₂,and CH₄ were higher than the zero-gradient measurement precision.② Based on the measurement,the small pond was the source of CO₂ and CH₄ for the atmosphere in summer,the mean emission flux of CO₂ and CH₄ was 0.038 mg·(m²·s)^-1 and 0.889 μg·(m²·s)^-1,respectively.The CH₄ emission fluxes from the small pond were more higher than the median value of emission for global lakes.The results indicated that greenhouse gas emission from small pond was an important part for estimating inland water greenhouse gas emissions,especially for CH₄ emission.These results can provide scientific reference for making emission inventory of regional greenhouse gas.