三峡库区澎溪河与磨刀溪电导率等水质特征与水华的关系比较

发布时间：2018-10-17 22:33

【摘要】：三峡库区北岸最大一级支流自三峡大坝2003年蓄水以来,频繁暴发水华,而毗邻的一级支流磨刀溪却少有水华暴发.本文以澎溪河和磨刀溪作为研究对象,于2014年春季和夏季三峡库区水华高发期对两条河流同时采样,对比分析两条河流水体水质以及叶绿素a(Chl-a)含量的时空变化,探索澎溪河水华暴发机理.结果表明:澎溪河Chl-a含量较磨刀溪高,澎溪河春季Chl-a最大值为60.5μg·L~(-1),夏季Chl-a最大值仅7.8μg·L~(-1);磨刀溪Chl-a变化趋势与澎溪河相反,磨刀溪春季Chl-a含量为2.92μg·L~(-1),夏季Chl-a达到7.48μg·L~(-1).澎溪河与磨刀溪春季和夏季节水体温度分层,为温跃层+滞温层模式,而没有混合层;两条河流Chl-a含量均位于水深10 m温跃层.澎溪河春季总氮(TN)、总磷(TP)平均值为2.305 mg·L~(-1)和0.053 mg·L~(-1),夏季为1.673 mg·L~(-1)和0.097 mg·L~(-1);磨刀溪春季为1.875 mg·L~(-1)和0.075 mg·L~(-1),夏季为1.79 mg·L~(-1)和0.054 mg·L~(-1).TN、TP水平均超过了国际公认发生富营养化的阈值;水体氮磷含量与Chl-a浓度并无显著相关性,营养盐并不是藻类生物量的限制性因素.然而在水体电导率的规律方面,两条河却存在很大的差异;春季,磨刀溪上游上层水体(0~10 m)电导率只有下游和长江干流的75%,来自长江干流的回水可覆盖至磨刀溪中游(断面MD03),与Chl-a在此处密集保持一致;夏季电导率和回水区分布与春季相似.与磨刀溪不同,澎溪河春季上游电导率为下游和干流的150%,长江干流回水可到PX04与PX05之间,上游高电导率对应着高Chl-a含量;澎溪河电导率与藻类生长分布表现出显著正相关关系,水体中除N、P营养盐外的其它离子对澎溪河水华暴发起重要作用.
[Abstract]:The largest first grade tributary on the north bank of the three Gorges Reservoir area has frequently erupted into Shui Hua since the three Gorges Dam was impounded in 2003, while the adjacent first grade tributary, the Grinding knife Creek, rarely broke out. In this paper, the water quality and chlorophyll a (Chl-a) content of the two rivers were compared and analyzed by sampling the two rivers simultaneously during the high incidence period of Shui Hua in the three Gorges Reservoir area in spring and summer of 2014. To explore the outbreak mechanism of Shui Hua in Peng Xi River. The results showed that the Chl-a content of Penghuanxi River was higher than that of Maotaoxi River, the maximum value of Chl-a was 60.5 渭 g L ~ (-1) in spring, the maximum value of Chl-a was only 7.8 渭 g L ~ (-1) in summer, and the change trend of Chl-a was opposite to that of Penaoxi River, the Chl-a content in spring was 2.92 渭 g / L ~ (-1) and Chl-a was 7.48 渭 g / L ~ (-1) in summer. The temperature stratification between Penghuxihe and Maotaoxi in spring and summer is the model of thermocline hysteretic layer without mixed layer, and the Chl-a content of the two rivers is located in the 10 m depth thermocline layer. The mean (TP) values of total nitrogen and phosphorus in spring were 2.305 mg L ~ (-1) and 0.053 mg L ~ (-1), 1.673 mg L ~ (-1) and 0.097 mg L ~ (-1) in summer, 1.875 mg L ~ (-1) and 0.075 mg L ~ (-1) in Groundknife Creek in spring, 1.79 mg L ~ (-1) and 0.054 mg L ~ (-1) in summer, respectively. The TN,TP level exceeded the internationally accepted threshold of eutrophication. There was no significant correlation between nitrogen and phosphorus content and Chl-a concentration, and nutrient was not the limiting factor of algal biomass. However, there are great differences between the two rivers in the regulation of water conductivity. The conductivity of the upper water body (010 m) in the upper reaches of Motaixi is only 75% of that of the lower reaches and the main stream of the Yangtze River. The backwater from the main stream of the Yangtze River can be covered to the middle part of the brook (section MD03), which is closely consistent with the concentration of Chl-a here, and the distribution of conductivity and backwater in summer is similar to that in spring. Different from Motaixi River, the upstream conductivity of Penghuxi River in spring is 150% of the lower reaches and the main stream, the return water of the main stream of the Yangtze River can reach between PX04 and PX05, the high conductivity of the upper reaches corresponds to the high Chl-a content, and the conductivity of Penghuxi River shows a significant positive correlation with the distribution of algae growth. The other ions in the water except for Nampa P nutrient play an important role in the outbreak of Shui Hua in Penghuxi River.
【作者单位】：西南大学资源环境学院;三峡库区水环境监测与模拟国际科技合作基地;三峡大学三峡库区生态环境教育部工程研究中心;加拿大温莎大学大湖环境研究中心;
【基金】：国家科技合作基地经费项目
【分类号】：X524

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