潮汐循环影响下上覆水环境因子和氮营养盐的变化及其相关关系

潮汐循环对水体理化特征的短期影响是潮汐河口各种理化参数变化的一个重要原因。通过崇明东旺沙堤外低潮滩和东海农场低潮滩采样及环境因子分析，发现崇明东滩各环境因子之间（除浊度外）相关性较好，均呈宽 “U”型变化；东海农场各环境因子之间相关性较差，变化不一致，且盐度、电导率变化与崇明东滩变化相反；受潮汐循环影响，崇明东滩涨潮初期各形态氮有明显释放过程，而东海农场的近底层水体在涨潮初期NH4+ N急剧下降，NOX- N缓慢下降；无论是在崇明东滩还是在东海农场，营养盐浓度受环境因子的共同影响，整个潮汐循环过程中总无机氮（TIN）与盐度呈显著线性负相关，这与整个长江口近岸水体的营养盐负荷相一致，长江上游淡水带来的高负荷营养盐流经河口进入海洋。

CHANGE OF ENVIRONMENTAL PARAMETERS AND INORGANIC NITROGEN IN OVERLYING WATER IN RELATION WITH TIDAL CYCLES

The influence of tidal cycle on the physical and chemical characters of overlying water is important for the variation of physical and chemical environmental parameters at the estuary. Based on the analysis of samples and environmental parameters taken from Chongming East Intertidal Flat and Donghai Beach, it is found that, in the intertidal flat, there were good relationships among these parameters. Except turbidity, other parameters represented the process with a “U” shaped variation; in Donghai Beach, the relationships among these parameters were weak. At the beginning of a flood in the intertidal flat, inorganic nitrogen was released rapidly; but in Donghai Beach, at the beginning, the NH4+ N fell down quickly and NO3- N decreased slowly. In Chongming East Intertidal Flat or in Donghai Beach, significant negative relationship was observed between TIN and S (salinity).