摘要
为探讨三峡水库调度运行背景下,库区回水区营养盐和叶绿素a时空变化及其相互关系,于2013年5月~2014年5月在三峡库区北岸最大、也是库区水华频发的支流——澎溪河的回水区高阳平湖进行了定点和高频监测.结果表明水体热分层是高阳平湖水华发生的诱导因素.高阳平湖水体热分层发生于春季(3月初),消亡于夏末(9月中旬),冬季没有分层.2014年春季,随着水体分层的发生和发展,表层叶绿素a在69 d内从14.92μg·L-1骤增至183.73μg·L-1,并暴发水华,之后叶绿素a随着混合层深度增加而下降.水体没有分层时,表、中和底层营养盐浓度相近;水体分层之后,各层磷浓度有了明显差异,表层和底层总磷浓度相差(0.18±0.04)mg·L-1.高水位期(9月至次年4月),高阳平湖硝氮和溶解性磷高于低水位期(5~8月)的含量,分别占总氮、总磷浓度的71.4%~95.4%和42.7%~94.4%,是总氮和总磷的主要组成部分,干流倒灌输入的硝氮和溶解性磷是其主要来源.
In order to explore the temporal and spatial variation of nutrients and chlorophyll a and their relationship in the Three Gorges Reservoir,nutrients and chlorophyll a were monitored chronically and frequently in Gaoyang Lake in Pengxi River in the Three Gorges Reservoir from May 2013 to May 2014. The study showed that the thermal stratification affected the vertical distribution of chlorophyll a and nutrients. The water thermal stratification in Gaoyang Lake occurred in early March and disappeared in the middle of September,and there was no stratification in winter( November to February of the second year). Chlorophyll a in the surface water increased from 14. 92 μg·L- 1to 183. 73 μg·L- 1and then the chlorophyll a concentration decreased with the increasing depth of the mixing layer( epilimnion) in the spring of 2014. Furthermore,phosphorus concentration was significantly different among layers when the water stratified and the concentration gradient of TP between the surface and the bottom was( 0. 18 ±0. 04) mg·L- 1. When water was not stratified in Gaoyang Lake,the surface,middle and bottom layers had similar concentrations of chlorophyll a and nutrients, respectively. Nitrate N and dissolved phosphorus were the major components of TN and TP,respectively,during the high water level period in Gaoyang Lake with nitrate N accounting for 71. 4%-95. 4% of TN and dissolved phosphorus 42. 7%-94. 4% of TP,showing that the backwater from the mainstream of Yangtze was the main source of nitrate N and dissolved phosphorus in Gaoyang Lake.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第6期2061-2069,共9页
Environmental Science
基金
国家国际科技合作专项项目(2013DFG92520)
关键词
三峡库区
澎溪河回水区
营养盐
叶绿素A
时空变化
Three Gorge Reservoir
Pengxi River backwater area
nutrients
chlorophyll a
temporal and spatial variation
