三峡水库香溪河库湾水-气界面N_2O通量特征

Characteristics of Nitrous Oxide Flux Across Water-air Interface of Xiangxi River Bay of Three-Gorges Reservoir

采用气象色谱-密闭式暗箱法对三峡水库香溪河库湾水-气界面N2O通量进行了为期1年的观测.结果表明,香溪河库湾水-气界面N2O通量呈明显的季节性变化特征,秋末、冬季N2O释放通量高于其他季节,且呈明显的波动状态;夏季和秋季N2O排放水平较低,通量变化范围较小.总体上,香溪河库湾水-气界面N2O全年呈释放状态,但释放通量较小,与加拿大魁北克地区水库N2O释放通量相当.下游A点的释放通量明显高于中游B点,其年平均释放通量分别为0.226mg.m-2.d-1和0.164mg.m-2.d-1.通过对N2O释放通量与环境因子的相关性分析发现,香溪河下游A点的N2O释放通量受气温、水温、pH值等影响显著;而B点的N2O释放通量除与气温相关性较显著外,与其他环境因子的关系不显著.

With the GC（Agilent 7890A） and static-closed-chanber method,a 1-year monitoring was carried out to understand the nitrous oxide（N2O） flux across the water-air interface of the Xiangxi River Bay,the Three-Gorges Reservoir.It indicated that the flux of N2O across the water-air interface appeared an obvious seasonal variation characteristics,the releasing flux of N2O in late autumn and winter was higher than other seasons,and the fluctuations were obviously.The emission of N2O in summer and autumn was lower and the flux changes in a smaller range.On the whole,the N2O across the water-air interface of the Xiangxi River Bay was emitted all year,and the releasing flux of N2O in downstream（A site） was significantly higher than mid-stream（B site）.And the flux of N2O in sites A and B was relatively small,with the annual average releasing fluxes were 0.226 mg·m-2·d-1 and 0.164 mg·m-2·d-1,respectively.Through the correlation analysis of N2O flux and environmental factors,the results show that the flux of N2O has good correlation with temperature and pH in downstream（A site）;but in mid-stream（B site） the correlation is not obvious,except for the air-temperature.