寒旱区湖泊浮游植物特征及其对营养状态的指示作用

为揭示内蒙古典型湖泊浮游植物群落特征及其对营养状态的响应,于2019年和2020年7月对呼伦湖,岱海,乌梁素海和居延海浮游植物和水质理化指标进行取样调查.结果显示,呼伦湖,岱海,乌梁素海和居延海分别鉴定出浮游植物101种,44种,125种和42种,绿藻门,硅藻门和蓝藻门是其优势门类.调查期间4个湖泊浮游植物的总丰度分别为5.71×10⁵,0.18×10⁵,3.45×10⁵和6.96×10⁵cells/L;根据优势度分析,居延海优势种最少为6种,其他湖泊优势种都在10种以上;CCA分析表明,综合营养指数(TLI),水温(T),总溶解性固体(TDS),氨氮(NH₄⁺-N),盐度(SAL),pH值(P<0.01)是浮游植物优势种的主要影响因子.4个湖泊的浮游植物Shannon-Wiener多样性指数(H′),丰富度(D),均匀度(J)指数均值分别为1.4,0.38和2.79(呼伦湖),2.28,0.87和1.42(岱海),2.99,0.74和4.46(乌梁...

Characteristics of phytoplankton in cold and arid areas and their indicator of trophic status

To reveal the characteristics of phytoplankton community structure and their response to nutrient, phytoplankton and physicochemical indexes of water quality in Lake Hulun, Daihai, Ulansuhai and Juyanhai were sampled and investigated in July 2019 and July 2020. 101, 44, 125 and 42 phytoplankton species were identified in Lake Hulun, Daihai, Ulansuhai and Juyanhai with a total phytoplankton abundance of 5.71×10⁵, 0.18×10⁵, 3.45×10⁵ and 6.96×10⁵ cells/L, respectively. Chlorophyta, Diatoms and Cyanobacteria were the dominant phyla. However, only 6dominant species were identified in Juyanhai, which was the least compared with more than 10 dominant species in the three other lakes. The dominant species of phytoplankton were mainly impacted by TLI, T, TDS, NH₄⁺-N, SAL and pH (P<0.01). The mean values of phytoplankton Shannon-Wiener diversity (Hx), richness (D) and evenness (J) were 1.4, 0.38 and 2.79 in Hulun Lake, 2.28, 0.87 and 1.42 in Daihai, 2.99, 0.74 and 4.46 in Ulansuhai, 2.39, 0.75 and 0.75 in Juyanhai, which indicated the corresponding evaluation results were medium rich/medium/medium nutrition, medium/medium rich/poor nutrition, medium/poor medium/poor nutrition, medium /moderate/poor nutrition, respectively. However the evaluation results of the comprehensive nutrition index (TLI) were severe eutrophication, moderate eutrophication, mild eutrophication and moderate eutrophication, respectively. Obviously, the evaluation results of the three approaches were different. On the whole, the evaluation result of phytoplankton index was significantly lower than that of physical and chemical indicators. This might be because the three diversity indexes were not only affected by the comprehensive nutrition indexes like TP, TN, SD and Chl.a, but also significantly correlated with T, pH, SAL and TDS. The analyzed results showed that J was significantly correlated with all the indexes, while Hx was significantly correlated with the indexes that were related to the comprehensive nutritional indexes and D was significantly correlated with T, pH, SAL and TDS. Therefore, the use of biological evaluation such as biodiversity alone may not be applicable to the lakes in the Inner Mongolia Plateau and it is suggested to use multiple evaluation methods in combination with physical and chemical indicators for a comprehensive evaluation.