水质改善的浮游植物群落演替机制模拟研究

模拟了广州市某河流的不同水质改善阶段，并研究其对铜绿微囊藻（Microcystis aeruginosa）、斜生栅藻（Scenedesmus obliquus）、短线脆杆藻（Fragilaria brevistriata）和易变裸藻（Euglena mutabilis）生长及超氧化物歧化酶（SOD）活性的影响.同时，考察了由4种藻类构成的人工群落的生长特征和群落演替率，以探讨河流水质改善过程中浮游植物群落演替机制.结果表明：4种藻类对氮、磷营养盐和COD_Cr等胁迫的响应程度差异及种间相互竞争作用等是水质改善过程中导致浮游植物群落演替的影响因素；水质改善初期（1~3 d），群落演替率与改善程度呈显著的正相关关系（p<0.05）；但较长时间（约13 d）处于相对稳定的环境条件下时，群落演替速率将趋于零，从而达到一个新的稳定状态.水质的不断改善将导致浮游植物的种类和数量呈现出蓝藻和裸藻逐渐减少，而绿藻和硅藻逐渐增多的变化趋势.

Simulation of phytoplankton community succession mechanism of water improvement

This study investigated the effect of different stages of simulated river water on the growth of Microcystis aeruginosa, Scenedesmus obliquus, Fragilaria brevistriata and Euglena mutabilis and the activity of superoxide dismutase (SOD). We also explored the succession mechanism of phytoplankton community by detecting the specific growth rate and community succession rate. The results showed that the differences of responsiveness for the stress of high or low of nutrients and dichromate oxidizability (COD_Cr), and competition of these species were important influence factors of phytoplankton community succession. A significant positive correlation (p<0.05) between community succession rate and improvement stages of water at the initial period (1~3 day) was observed. However, the community succession rate approached to zero, when the community was in a relatively stable environment conditions for a longer period (approximately 13 days). The richness and quantities of Cyanophyta and Euglenophyta decreased, while Chlorophyta and Bacillariophyta gradually increased.