中文摘要：

2013年1-12月在小江水华暴发的敏感区域高阳断面开展了水文、营养盐、叶绿素a等指标长期、定点监测,分析库湾水体叶绿素a及环境因子的时空变化特征及其相互关系。结果表明,高阳断面水体在1月、10-12月处于混合状态,3-8月则处于弱分层到稳定分层状态。水体处于混合状态时,各层营养盐浓度变化不显著,处于分层状态时,则呈现较显著差异;时间分布上,冬季氮磷营养盐浓度（TN：1.52-1.74 mg/L,TP：0.092-0.095 mg/L）略高于夏季（TN：1.16-1.56 mg/L,TP：0.037-0.085 mg/L）,干流水体倒灌作用对其影响显著。叶绿素a浓度呈现夏季高、冬季低的趋势,水体分层对叶绿素a垂向分布影响显著;当水体处于分层状态时,表层叶绿素a浓度（18.56-92.23 mg/m3）明显高于中、底层（2.54-21.56 mg/m3）。营养盐为小江高阳叶绿素a变化的限制因素,各层水体叶绿素a浓度与硝氮和可溶性磷酸盐呈显著负相关。表层水体叶绿素a与环境因子相关性较强,叶绿素a与营养盐、溶解氧、透明度、水温、表底温差等呈极显著相关（P〈0.01）;中层叶绿素a与营养盐、水温、透明度、水深、水体稳定系数等呈极显著相关（P〈0.01）,表明水体扰动是影响中层水体叶绿素a增长的关键因素之一;底层水体叶绿素a与硝氮（P〈0.01）、磷酸盐（P〈0.05）、水深（P〈0.05）呈极显著或显著相关。

英文摘要：

Eutrophication in the tributaries of Three Gorges reservoir has intensified since impoundment in 2003 and the ecological impacts have received increasing attention at home and abroad. High nitrogen and phosphorus levels are the primary factors resulting in tributary eutrophication and algal blooms. Hydrological factors,including intrusion of Yangtze River water,lower velocity and extended inundation exacerbate the situation. Comprehensive monitoring and analysis of the hydrology,water quality and aquatic ecology in sensitive areas increases our understanding of the algal bloom mechanism. The Gaoyang section of Xiaojiang River is a typical algal bloom area and was monitoring monthly from January to December 2013. Temporal and spatial distributions and the relationship of hydrology,nutrients and chlorophyll a were analyzed. The objective was to explore the eutrophication mechanism and algal bloom triggers in tributaries of Three Gorges Reservoir. Three sampling sites were set on the left,right and in the middle of the Gaoyang section. In the period from the 20（th） to 25（th） of each month,water samples were collected at three depths（ surface： 0. 5 m from the surface; middle： 1/2 water depth; bottom： 0. 5 m above the bottom） for determination of total nitrogen（ TN）,ammonia nitrogen,（ NH3-N）,nitrate nitrogen（ NO3-N）,phosphate（ PO4（3-））,total phosphorus（ TP） and chlorophyll a. In situ measurements included water temperate,water depth,flow velocity,p H,DO and turbidity. The water was well mixed from October to the following January,but was thermally stratified from March to August. When mixed,the nutrient concentrations in different water layers were not significantly different,but nitrogen and phosphorus concentrations were significantly different among the three layers when stratified. The concentrations of nitrogen and phosphorus were higher in winter（ TN： 1. 52-1. 74 mg/L,TP： 0. 092-0. 095 mg/L） than in summer（ TN： 1. 16-1. 56 mg/L,TP： 0. 037-0. 085 mg/L） and