高潮滩盐沼前缘沉积物—水界面NH_4^+-N浓度的潮周期变化

The features of NH_4^+-N concentration changes within a tidal cycle at the sediment-water interface in the edge of of high tidal flat

基于高精度测量仪器Vectrino小威龙点式流速仪,对崇明东滩高潮滩盐沼前缘进行为期7d的连续观测和采样.采用纳氏试剂光度法对样品进行分析,分析结果表明:NH4+-N浓度分布在0~1.1652 mg.L-1,平均为0.3830 mg.L-1;涨潮时潮滩沉积物成为NH4+-N的源,落潮时潮滩沉积物表现为NH4+-N的汇;沉积物—水界面NH4+-N垂直分布存在复杂的变化特征;近底层10cm处潮汐流速对NH4+-N浓度的影响机制十分复杂.

Using the high precision apparatus -Vectrino Velocimeter, we made a seven -day continuous observation and sampiing on the edge of the salt marsh sediment - water interface in east ChongMing High Tidal Flat. The samples were analyzed by Nessler＇s reagent dectrophotometry. The analysis results indicated that the ammonia concentration of NH4^＋-N was between 0 and 1. 1652 mg ·L^-1 in the vertical profile, with an average of 0. 3830 mg · L^-1; during flooding phase, tidal flat sediment became a source of NH4 ^＋-N while during ebbing phase, it became a collection of NH4^＋ -N. The vertical distribution of NH4^＋ -N in sediment -water interface was complex. In the water layer of the lowest 10 cm thick, the influence mechanism that tide velocity would have on NH4 ^＋-N was very complex.