贵州高原红枫湖水库季节性分层的水环境质量响应

Features of the water column stratification and the response of water quality of Hongfeng reservoir in Guizhou,China

为了揭示贵州高原深水水库水体的垂直分层结构及其水环境质量响应特征，于2008年8月-2009年10月对红枫湖水库5个采样点进行了45次采样，对水文、营养盐等湖沼学变量季节动态和分布进行了分析，探讨了季节性水质恶化事件的发生机制．结果表明，红枫湖水库水体呈单循环混合模式，在4－9月形成分层，但没有典型分层湖泊的温跃层变化，这种不显著的分层导致了水化学的分层．叶绿素a、总磷、总氮和氨氮平均值分别为13．6mg／m^3,0．063mg／L，1．22mg／L，0．347mg/L；透明度为1．9m．指示该水库处于中-富营养状态．分层期底层溶解氧在0．3-6．9mg／L之间、平均为2．6mg／L，氮磷质量比在8-104之间，表明红枫湖水库是一个底层滞留带季节性缺氧的高氮、磷限制型水库．贵州高原深水水库季节性水质恶化事件与水体分层结构失稳有关，是富营养化水库在气温骤降时发生“翻湖”所导致的结果，也是贵州高原深水水库富营养化的另一种表现形式．

To reveal the features of the water stratification and the response of water quality of Hongfeng reservoir, in Guizhou Province of China, main limnological variables including hydrological and environmental factors were observed 45 times, from August 2008 to October 2009, at five sampling stations. An event of water quality abruptly degeneration was discussed. The the thermal stratification was monomictic, which formed from April to September, but not strongly, which caused chemical stratification and affected water quality. The mean concentrations of chlorophyll-a, TP, TN, NH4^＋-N and SD were 13.6mg/m^3, 0.063mg/L,1.22mg/L,0.347mg/L and 1.gin, respectively, indicating that the reservoir was meso-eutrophic. Dissolved oxygen was between 0.3 to 6.9mg/L during the stratification period, the rational of N/P was between 8 to 104,and mean that the reservoir was limited by phosphorus, but nitrogen, and hypolimnion seasonal anoxia.Seasonal deterioration of water quality was associated with the unsteady structure of water stratification, which was a result of vertical mixing when air temperature drawdown in eutrophyical Reservoir, and also was another manifestation of eutrophycation of deep water rescrvior in Guizhou Altiplano.