水布垭水库CO_2排放通量时空特征及其与环境因子的响应研究

利用静态浮箱-LGR快速温室气体分析仪法,于2010年7月、9月和11月对清江流域水布垭水库库区9个典型采样点CO2排放通量进行了原位观测实验,并就CO2排放通量对环境因素的响应关系进行了分析。结果表明：7月份水库水体表现为CO2的＂汇＂,吸收CO2最大的点分别位于两条支流及上游来水上。9月份水库水体表现为排放CO2。11月份水库水体各点均表现为较强的排放,其中1、2、3号点的排放量最大,分别达到122.37 mmol/m2.d、123.96 mmol/m2.d、166.863 mmol/m2.d。借助于地理信息系统Kriging插值技术获取水库不同观测时段CO2排放通量的空间分布特征。插值结果表明：7月份水布垭水库CO2排放通量空间分异主要表现为水库上游入口和典型支流的吸收最显著,坝前水体CO2吸收居中,而水库中部范围内水体对CO2吸收较差。9月份和11月份水布垭水库CO2排放通量空间分异相似,从水库上游到坝前,排放量依次增加,到坝前区域排放量达到最大。水库水体CO2排放通量与环境因素的响应研究表明,叶绿素a浓度、溶解氧含量、水体总有机碳含量3个因素是影响CO2排放通量的重要因素。其中叶绿素a浓度、溶解氧含量与CO2排放通量之间呈典型的负相关关系,水体总有机碳与CO2排放通量呈显著的正相关关系。温度、pH值和透明度对于CO2排放通量的影响较小。水库水体CO2排放通量还受到水库运行时间与水库运行方式的影响。

Study on spatiotemporal characteristics of CO2 emission and effects of environmental factors in Shuibuya reservoir

Seasonal dynamic changes of CO2 emission were studied in situ in Shuibuya reservoir of Qingjiang basin in July,September and November of 2010,using the static chamber-LGR techniques,and the correlationship between emission flux and environmental factors was analyzed.The results showed that CO2 was absorbed in July with the sampling point of maximum absorption located in the main tributaries,while in September the reservoir water body diffused CO2.In November,the emission flux at all the sampling points was significant and the fluxes at sampling points NO.1~3 of greatest emission were 122.37,123.96 and 166.863 mmol/m2d,respectively.Spatial distributions of different seasons calculated by Kringing interpolation indicate that the emission varied quite significantly.In summer the reservoir’s upstream region and main tributaries showed obvious absorption,while in autumn and winter an increasing trend of emissions appeared from the inlet to the dam.The emission from the reservoir water was dominantly controlled by environmental factors of chlorophyll a,dissolved oxygen and total organic carbon,and it has a negative correlation with Chlorophyll a and a positive correlation with total organic carbon.Temperature,pH and transparency have a slight influence and the operation mode and reservoir age show some effect on the emission.