三峡水库成库初期营养盐与浮游植物分布特征

根据2003-09-08～2003-09-15航行11个点位测试数据,分析了三峡水库成库后营养元素及浮游生物量的分布特征,初步探讨了营养盐分布与Chla的关系.结果表明,调查区域营养盐浓度较高,其中TN各测点均超过国家地表水环境质量标准Ⅲ类水标准,含量范围为1.01～1.35 mg·L^-1.TP含量范围为0.028～0.054 mg·L^-1;K含量范围为2.80～3.44 mg·L^-1;TOC含量范围为1.92～2.59 mg·L^-1,Chla含量范围为1.58～7.35mg·m^-3,平均浓度为4.69 mg·m^-3.利用相关分析方法,分析了Chla与营养盐之间的关系,表明Chla与NO₃^--N成显著正相关(r=0.728 7);与浊度成显著负相关(r=-0.920 7).利用系统聚类方法分析三峡水库水体指标,随长江流向明显分为3类,即上游区(长寿、涪陵、丰都、忠县)、中游区(万州、云阳、奉节)和下游区(巫山).硅藻在4个测点均为优势种群,占总量的86%,平均为129 844个/L,浮游植物量沿水流方向有增高趋势.

Distribution Features of Nutrient and Phytoplankton in Incipient Three Gorges Reservoir

The distribution features of nutrient and chlorophyll a were determined by cruise during 2003-09-08 approximately 2003-09-15 with 11 sites in the Three Gorges reservoir. The results showed that the concentration of nitrogen was exceed the national surface water body quality standard III. The concentration of nitrogen range 1.01 approximately 1.35 mg x L(-1); Total phosphorus range 0.028 approximately 0.054 mg x L(-1); Kalium range 2.80 approximately 3.44 mg x L(-1); Total organic carbon range 1.92 approximately 2.59 mg x L(-1); Chlorophyll a range 1.58 approximately 7.53 mg x m(-3). The average concentration of chlorophyll a was 4.69 mg x m(-3) at surface layer. The correlation of nutrient and chlorophyll a were researched. It indicated there was a significant positive correlation (r = 0.7287) between chlorophyll a and NO3(-)-N.There was a significant negative correlation (r = -0.9207) between chlorophyll a and turbidity. Using the method of system cluster, it showed there was distinct distribution features which can be divided into three clusters. The upper river areas cluster included Changshou, Fuling,Fengdu, Zhongxian; The middle river areas cluster included Wanzhou, Yunyang and Fengjie; The down river areas included Wushan. The rate of diatom in phytoplankton was about 86%. Diatom was absolute predominance on 4 monitoring sites. The average of diatom was 129844 cells x L(-1). Amount of phytoplankton was increased along the river flow direction.