【摘要】 采用通量箱-气相色谱法对三峡水库香溪河库湾秋季水-气界面温室气体(CO2、CH4、N2O)交换通量进行了连续24 h昼夜观测.结果表明,水-气界面CO2、CH4、N2O的释放通量具有明显的日变化特征:水体除去下午17:00及凌晨05:00吸收CH4外,其余时刻均向外界大气排放CH4,且在凌晨01:00达到排放高峰.CO2和N2O通量的变化规律一致,两者全天均表现为向大气释放;且CO2和N2O通量的昼夜差异较大.CO2白天释放通量范围在20.1～97.5 mg.(m2.h)-1之间,夜间释放通量范围在32.7～42.5 mg.(m2.h)-1之间.N2O白天释放通量范围在18.4～133.7μg.(m2.h)-1之间,夜间释放通量范围在42.1～102.6μg.(m2.h)-1之间.通过相关性分析,秋季香溪河水-气界面CO2交换通量与风速呈显著正相关,与pH值显著负相关,与Chl-a有一定相关性;CH4交换通量与气压有一定的相关性;N2O交换通量与pH值显著正相关.更多还原

【Abstract】 With the closed chamber and gas chromatography method,a 24-hour continuous monitoring was carried out to understand the greenhouse gases fluxes across the water-air interface of the Xiangxi River Bay,the Three-Gorges Reservoir in Autumn.Results indicated that the fluxes of CO2,CH4 and N2O across the water-air interface showed an obvious diurnal variation.The absorption and emission process of CH4 showed strong diurnal variation during the experimental period,reaching the highest emission at 1 am,whereas CO2 and N2O were emitted all day.The fluxes of CO2 ranged from 20.1-97.5 mg·(m2·h)-1 at day and 32.7-42.5 mg·(m2·h)-1 at night,the fluxes of N2O ranged from 18.4-133.7 μg·(m2·h)-1 at day and 42.1-102.6 μg·(m2·h)-1 at night.The fluxes of CO2 had positive correlation with wind speed and negative correlation with pH.The fluxes of N2O had positive correlation with pH.更多还原