三峡蓄水前后长江口水域营养盐浓度变化特征和通量估算

Concentration characteristics of nutrients and influx calculation in Changjiang Estuary before and after water storage of Three Gorges Project

根据2003至2007年对长江口大通站附近水域的调查,比较和讨论了三峡工程蓄水前后该水域溶解态营养盐的浓度变化特征:蓄水后NH4+、NO2-浓度的季节分布发生了较大的变化,表现为浓度峰值均出现在2月份,高出其余3个月份约一个数量级,季节分布差异显著,RSD分别为142%和119%。蓄水后,营养盐浓度除了PO43-外均呈明显下降趋势。估算并研究了长江入河口蓄水前后营养盐通量的季节变化、年际变化,并利用月通量序列以及相应的流量序列,拟合出利用已知的月均流量预测进入河口区的月通量的关系函数。

Based on the investigations near Datong Station in Changjiang Estuary from 2003 to 2007, the dissolved nutrient concentrations before and after water storage of Three Gorges Project were compared. The seasonal concentration characteristics of NH4^＋ , NO2^- were changed much after water storage, the maxim average concentrations occurred in Feb. which was higher about 10 times than other month（May, Aug. Nov. ）. The seasonal concentrations were changed remarkably, and the RSD is 142% and 119% , respectively. The nutrient concentrations were declivous trend except PO4^3-. The monthly and annual mean flux of nutrients are estimated an analyzed. Further, fitting functions between the discharge and fluxes are obtained to predict the monthly flux with the monthly discharge.