乌江河流-水库体系浮游植物功能群演替及其环境影响因子辨识

筑坝拦截阻断了河流连续体,改变了河流原始自然的生态系统。为了解河流筑坝对浮游植物功能群的影响,按季度对乌江流域支流猫跳河和三岔河的水库及入库河流进行调查,分析了浮游植物功能群及其相关环境因子。结果表明,河流出现频率大于20%的浮游植物功能群有6种,主要优势功能群均为B\MP;而不同水库中功能群组成各不相同,且出现频率大于20%的浮游植物功能群有11种,其中红枫湖水库以功能群S1\D为绝对优势功能群,平寨水库优势功能群为B\C,而普定水库和引子渡水库的优势功能群均为B\D\P\Lo。冗余分析(RDA)结合逐步多元回归分析显示,营养盐对河流浮游植物功能群组成影响并不显著,而库区浮游植物功能群动态变化主要受温度以及溶解无机碳(DIC)、NO_3~-、PO_4~(3-)等环境因子的影响,红枫湖水库优势功能群丰度与NO_3~-显著正相关,而三岔河流域的3座梯级水库优势功能群丰度均与DIC和PO_4~(3-)显著正相关。

Succession of Phytoplankton Functional Groups in the Wujiang River- reservoir System and Its Environmental Impact Factors Identification

A dam can block the continuous stream and affect the original ecosystem of the river. In order to understand how the dam affects the composition of phytoplankton functional groups, water and phytoplankton samples were collected seasonally in streams and reservoirs on the river to analyze the phytoplankton functional group succession and its relationship with environmental factors. The results showed that there were 6 species in the river ecosystem whose occurrent frequency were more than 20% and their dominated functional groups were B\MP, while there were 11 species in reservoir ecosystems whose occurrent frequency were more than 20% and their functional group compositions showed significant spatial heterogeneity, the S1\D was the predominant functional group in the Hongfenghu reservoir, the B\C was dominant functional group in the Pingzhai reservoir, and the B\D\P\Lo was the dominate functional group in Yinzidu and Puding reservoirs. The redundancy analysis (RDA) combined with the stepwise multiple linear regression analysis showed that nutrients had no significant effect on the composition of phytoplankton functional group in the river ecosystems. However, the dynamic changes of phytoplankton functional group in reservoirs were mainly affected by temperature, DIC, NO₃^-, and PO₄^3-. The study also found that the abundance of dominant functional group correlated significantly negatively with NO₃^- in the Hongfenghu reservoir but with DIC and PO₄^3- in other three reservoirs on the Sanchahe river.