渭河流域硅藻群落特征及水生态健康评价

Diatom Community Structure and Aquatic System Assessment of Wei River Basin

为比较丰水期和枯水期硅藻群落结构特征的差异性,对渭河流域进行水生态健康评价,于2012年10月(丰水期)和2013年4月(枯水期)对渭河流域60个采样点进行调查.结果表明,丰水期共采集到硅藻221种,枯水期为148种.多响应置换过程结果显示,渭河水系、泾河水系和北洛河水系硅藻群落存在显著性差异.丰水期渭河水系和北洛河水系硅藻丰富度、ShannonWiener多样性指数和均匀度指数平均值分别为30、3.05、0.63和37、3.42、0.66,显著高于枯水期的23、2.11、0.46和23、2.52、0.56.泾河水系丰水期和枯水期硅藻参数无显著性差异.典范对应分析结果表明:丰水期影响渭河水系、泾河水系和北洛河水系硅藻群落结构的主要环境因子为Flux(流量)、ρ(SS)和ρ(TDS)(TDS为总溶解固体);枯水期主要影响因子分别为ρ(NH4+)、ρ(SS)和Hard(硬度).应用硅藻生物完整性评价法(D-IBI)和生物硅藻指数法(BDI)对渭河流域进行健康评价,其结果显示,渭河流域丰水期和枯水期整体健康状况一般,渭河水系上游及右岸支流、泾河水系源头及北洛河水系中游地区健康状况较好,渭河水系下游、泾河水系中下游以及北洛河水系上游和下游地区健康状况较差.

To evaluate the condition of the Wei River Basin,60 sampling sites were selected to investigate the diatom community structure during the wet season（ October 2012） and the dry season（ April 2013）. A total of 221 species of diatom were identified in the wet season and 148 species were observed in the dry season. On the basis of the Multi-Response Permutation Procedures（ MRPP）,the diatom community structure showed a significant difference between the Wei River,Jing River and Beiluo River. The species richness,ShannonWiener diversity and evenness in the wet season（ Wei River： 30,3. 05,0. 63; Beiluo River： 37,3. 42,0. 66） were significantly higher than those in the dry season（ Wei River： 23,2. 11,0. 46; Beiluo River： 23,2. 52,0. 56）. However,the metrics of diatom were similar in both seasons for the Jing River. According to Canonical Correspondence Analysis（ CCA）,the results showed that flux,suspended solids and the total dissolved solids were the main factors affecting the community structure of diatom in the wet season in the Wei River,Jing River, and Beiluo River, respectively, while ammonia,suspended solids and hardness were the main factors in the dry season. An assessment of river condition was made using the Diatom Index of Biological Integrity（ D-IBI） and Biological Diatom Index（ BDI） in different seasons. The results in both seasons showed that the condition of the Wei River Basin was fair.The health condition in the upstream and the right bank branch ofthe Wei River was excellent,as was the upstream of the Jing River and the midstream of the Beiluo River,whereas the downstream of the Wei River,the middle and downstream of the Jing River and headwater of the Beiluo River were poor.