中文摘要：

在三峡水库澎溪河回水区春季水华连续暴发期间（2010年4月10日至5月25日），对渠马至河口总计5个采样断面进行监测。结果表明水华期间水体叶绿素a（Chla），溶解氧（DO）及CO2分压（P（CO2））分层现象明显，表层水体受浮游植物光合作用的影响P（CO2）较低，并且日照充足时，水体为CO2的汇。研究期间表层水体P（CO2）最小值出现在4月2513双江断面，为4．3Pa，吸收通量为-0．28mmol／（m^2·h）。P（CO2）随水深迅速增加，并在10～15m趋于稳定。偏最小二乘回归分析（PLS）表明澎溪河水华期间，浮游植物的生长代谢是控制P（CO2）的关键因素，水温与P（CO2）负相关，但并不构成对P（CO2）的绝对影响。通过引用印（CO2）、AD0参数，观测到了澎溪河水体水华暴发的3个阶段，期间澎溪河表层水体经历了从碳汇到碳源最后又回到碳汇的过程。

英文摘要：

Monitoring of the partial pressure of CO2 （p （CO2 ） ） was conducted in the backwater area of Xiaojiang River in Three Gorges Reservoir. Water samples were taken from the five cross sections in the Quma-Heikou reach of Xi- aojiang River during the spring phytoplankton bloom from April 10 through May 25, 2010. Results show that there are obvious stratifications of chlorophyll a （Chla） , dissolved oxygen （DO） , and p（ CO2 ） in water columns. The value for p（ CO2） is low in surface water due to phytoplankton photosynthesis effects. The surface water can be the CO2 sink if sufficient sunshine presents. A minimum value of 4. 3 Pa for p （ COs ） was observed from the cross section of Shuangjiang on April 25, with an absorption flux of -0.28 mmol/m2/h. The value for p（ CO2） increases vertically with the water depth, and will be stabilized in the 10 - 15m layer of water. The partial least squares regression analy- sis reveals that the growth and metabolism of phytoplankton in the surface water are the key factors controlling p （CO2）. A negative relationship between the water temperature and p（ COz） has been found, but its influence on p （ COz） is minimum. Using the indices of Excess p （ CO2 ） （ Ep （ CO2 ） ） and apparent oxygen utilization （ADo） , a three-stage bloom of phytoplankton in the Xiaojiang River was observed, during which, the surface water had gone through a sink-source-sink cycle for CO2.