苏州河、黄浦江水体中有机物、营养盐季节变化及其环境效应

SEASONAL VARIATIONS OF ORGANIC MATTER AND NUTRIENTS OF SUZHOU RIVER AND HUANGPU RIVER AND THE ENVIRONMENTAL EFFECT

2006年11月—2007年11月期间,每月采集苏州河、黄浦江表层水样,测定有机物及溶解态营养盐含量.苏州河、黄浦江均呈现高有机物,高营养盐含量的特征.有机物含量月际变化不大,夏季稍高.Si、N、P呈现不同的季节变化特征.SiO3-Si的年内变化与浮游植物的生长规律一致,冬季最高,春季慢慢降低,春末出现最低值,后夏季慢慢升高,秋季又出现高值.受浮游植物生长、污水排放、物理因素(温度、溶解氧)等多重因素影响,N、P的年内变化较Si复杂.总溶解态无机氮(DIN)为枯水期大于丰水期,下游含量大于上游,三种形态的N所占DIN比例也有季节变化.NO3-N、NH4-N均为枯季高,洪季低,NO2-N则呈现夏季高,冬季低的特点.PO4-P黄浦江月际变化不大,苏州河,尤其下游站位,变化相对剧烈.从输送通量的计算结果来看,由于苏州河径流量较低,对黄浦江的影响不大,而黄浦江对长江口的影响则不容忽视.

Surface water of Suzhou River and Huangpu River was collected monthly from November 2006 to October 2007.Concentrations of organic matter and nutrients were analyzed.Both rivers were characterized by high concentrations of organic matter and nutrients,especially Suzhou River.Concentration of organic matter did not show much seasonal variation except a rise in the summer.Si,N,P exhibited different seasonal variation.Variation of SiO3-Si was consistent with the growth of phytoplankton,which was high in the winter,but decreased in the spring,minimized in late spring,then increased in the summer,and got higher in the autumn.N,P were influenced by the phytoplankton,drainage,and some physical factors such as temperature and oxygen,and changed in a more complex pattern than Si.As DIN was concerned,both Suzhou River and Huangpu River were characterized by high DIN in dry season and low DIN in flood season,and higher DIN down stream than up stream.NO3-N and NH4-N had similar behavior.NO2-N was high in summer because of the low dissolved oxygen concentration.The signature of PO4-P of Huangpu River kept constant but that of Suzhou River had a big variation especially at the down stream station.The transport flux of Suzhou River to Huangpu River is not large because of the small runoff volume.But the flux of Huangpu River to the Changjiang River can′t not be ignored especially in the dry season.