珠江三角洲密养池塘的水质特点分析

Water Quality Characteristics of Intensive Fish Ponds in Pearl River Delta

对珠江三角洲的几个典型基塘进行了一个养殖周期的跟踪调查,发现密养池塘中的NH4-、TN、COD、Chla等指标均有明显的升高,而NO3-、TP、SRP、BOD等指标无明显升高,DO没NO2-也占约+比例上升,占50%以上,NO2有明显下降。密养池塘无机氮的组成发生了明显的变化:NH4-比例,降到40%以下。池塘是以P为浮游植物生长的限制性因子。P的限制因素解除,浮10%,NO3游植物将迅速增长。池塘底泥中TP、TN、有机质明显高出基面堆叠土,以P的富集最为强烈。富营养化评价结果表明,珠江三角洲密养池塘达到了重度富营养化水平,而且养殖年限越高,富营养化程度越高。

Investigation on several typical intensive fish ponds in Pearl River Delta indicated that indices of NH^+_4、NO^-_2、TN、COD、Chla increased significantly ,while indices of NO^-_3、TP、SRP、BOD did not increased significantly and DO did not decreased significantly .The component of TIN changed obviously: NH^+_4 went up ,taking up over 50% , NO^-_2 was also up ,taking up about 10%, NO^-_3 was down ,taking up less then 40%. Element P was the limiting factor of intensive fishpond, once P was enough, the photoplankton would grow quickly. TP、TN、OM of the pond sediments were higher than that of the dike. P was strongly concentrated in pond sediments. The investigated ponds were all hypereutrophicate, and the longer of culture years ,the higher of the degree of eutrophication.