三峡库区支流富营养化及水华现状研究

三峡水库蓄水以来，库区支流水体营养状态、藻类生物量及群落结构发生明显改变，对不同蓄水阶段研究表明：库区支流富营养化程度加重，且时空差异显著，春、夏季富营养化程度严重，秋、冬季节相对较轻.整体上由蓄水前的贫 中营养状态转变为中 富营养状态。由于库区支流营养盐浓度高且蓄水前后相对稳定，对藻类生长不形成限制，因此支流富营养化加重的原因是蓄水后库区支流流速减缓，使得透明度增加，水体透光性增加，藻类生长环境改善，从而使生物量大幅度增加，库区支流藻类水华频繁发生，且优势种类趋向于多样化，硅藻、甲藻、隐藻、蓝藻、绿藻都可成为水华优势种，且整体组成呈现硅藻、甲藻下降，蓝藻、绿藻、隐藻上升的态势，演替趋势总体上由河流型向湖泊型转变。但随着蓄水位的上升，水华发生比率总体上有所降低

INVESTIGATION ON THE PRESENT SITUATION OF EUTROPHICATION AND WATER BLOOM IN THE BRANCHES OF THREE GORGES RESERVOIR

Since the first impoundment of Three Gorges Reservoir,trophic state,algae biomass and the structure of community has changed significantly.Series of investigating results during different impoundment stages showed that eutrophication of tributary river deteriorated and differed on time and space.The eutrophication in spring and summer were more serious than that in autumn and winter,making the general trophic state of ecosystem shift from oligotrophic-mesoerophic status to mesoerophic-eutrophic status.Nutri...