潮滩沉积物-水界面NH3-N交换通量的底栖藻类效应

在考虑底栖藻类效应的基础上,运用实验模拟技术,研究了“有光—无光”和“淹水—暴露”这两个典型潮滩环境条件下沉积物—水界面NH3-N的扩散通量变化,发现光照和暴露时间的长短显著影响沉积物—水界面NH3-N的迁移交换。暴露后淹水初期NH3-N由沉积物向上覆水释放,但在光照条件下由于底栖藻类的光合作用或吸收作用使得释放通量减少甚至改变了扩散方向。随着暴露时间的增加,NH3-N从沉积物向上覆水体释放通量减小。

Effect of benthic alga on ammonium flux in the intertidal sediment-water interface

The effect of benthic alga in the intertidal sediment-water interface is a key content of the balance of the nutrient in intertidal ecosystem.Illumination-dark and emersion-immersion temporally alternate in real intertidal world.These factors as well as benthic alga were simulated in the study to investigate the effect of benthic alga on ammonium flux in the sediments-water interface.The results indicated that emersion under illumination and in the dark affected ammonium exchange after immersion in sediment cores.In dark-emersed cores there was net ammonium efflux from the sediment into the overlying water after immersion.An illuminated emersion period reduced the flux of ammonium to the overlying water or affected uptake after immersion.The flux of ammonium to the overlying water reduced with the increased time of emersion.