上海滨岸潮滩水沉积物中无机氮的季节性变化

对长江口南翼上海滨岸带3个站点潮滩上覆水，沉积物和间隙水中的3态无机氮的含量分布的年度季节性监测研究表明：潮滩上覆水中溶解无机氮以NO3－N为主：表层沉积物中可交换态无机氮以NH4－N为主，约占70％－85％，沉积物间隙水中主要无机氮为NH4－N和NO3－N。潮滩水体中NH4－N的季节性变化幅度不大，而NO3－N和NO2－N的季节性变化明显，在冬季含量明显降低；但沉积物和间隙水中氮氨和硝态氮的浓度在冬季则有较大增加。初步探讨了潮滩水和沉积物中无机氮分布季节性变化的主要影响因素，估算了潮滩表层沉积物－水界面无机氮的扩散通量，指出NH4－N的扩散释放对滨岸水环境质量影响较大。

Seasonal Variation of Inorganic Nitrogen in Water and Sediment of Intertidal Flats on the Shanghai Coast

In 1998-1999, contents of inorganic nitrogen (NH_4-N, NO_3-N and NO_2-N) in water and sediment of intertidal flats of the Shanghai coast were investigated at three stations (CY, DH and LY). Results show that the main form of inorganic nitrogen in water of intertidal flats is of NO_3-N with a wide range (37.2~226.1 mol^-1); most of exchangeable N in surface intertidal sediments is of NH_4-N, accounting for 70%~85%; NH_4-N and NO_3-N are the main form of inorganic N in pore water of surface sediments. Content distributions of NH_4-N, NO_3-N and NO_2-N in water and sediment of intertidal flats vary seasonally. The basic factors affecting the seasonal variation of inorganic N were discussed. Moreover, the diffusion fluxes of NH_4-N, NO_3-N and NO_2-N between water and intertidal sediment interface were estimated, indicating that NH_4-N in sediments may play an important role in the Yangtze estuarine and coastal environment.