三峡水库大宁河回水区藻类生长与三态磷盐变化特征分析

多年的调查数据表明，每年的3～6月是大宁河回水区水体营养盐及藻类含量增长期。在2011年3—6月对大宁河回水区整个区域的调查过程中发现，水体磷盐含量从回水区上游至入长江河口逐渐增大，总磷0．010～0．257mg／L，溶解性磷0．010～0．208mg／L，正磷酸盐0．010～0．179mg／L；磷盐3个指标中，正磷酸盐变异性最大（各断面59％～85％），能够较好地反映藻类消耗磷盐的情况。正磷酸盐和藻类生物量呈显著负相关关系，且在自然水体中有明显分层。在室内培养条件下采用线性关系粗略分析，藻类能在水体正磷酸盐含量较低时释放和转化磷盐，其藻类生物量理论极限容量值略高于天然状态。室内培养藻类发现，藻类生长过程中先是个体的增长，之后数量增殖，但平均体积会变小。藻类生长活性有一个由强到弱然后再增强的过程，而较低正磷酸盐浓度会抑制藻类的生物活性使其一直处于一个较低的水平。

Variation of Three Forms of Phosphorus with Algae Growth in the Backwater Area of Daninghe River of the Three Gorges Reservoir

The investigation data ot several years snows that the nutrients and the algae are growing rapidly in the backwater area of Daninghe River every March till June. An investigation carried out in March -June of 2011 finds out the content of hosphorus is gradually increasing from the upper backwater area to the Yangtze River estuary, P with the total phosphorus from 0. 010 -0. 257mg/L, the dissolved phosphorus 0. 010 -0. 208 mg/L and orthophos- phate 0. 010～ 0. 179 mg/L. Of the three indicators, the orthophosphate varies in a wide range （each cross - sec- tion 59% -85% ） , and it better reflects the consumption of the phosphate salts by the algae. The orthophosphate and the algae are in a negative correlation, and they are stratified in the water. In a static laboratory test, we notice that the algae could release and transform the phosphorus when the orthophosphate content of the environment is rel- atively low. The theoretical maximum algal biomass slightly exceeds the natural amount. The algal biomass grows first by single algal growth, and then by quantity but with averagely smaller size. The algal growth experiences a process from active to less active and then being active again. The low concentration of orthophosphate could inhibit the algal activity and keep it at a low level as well.