风浪作用下入湖河口内源释放特征

Release characteristic of nutrient from sediment in the estuary driven by wind and wave

采用Y型沉积物再悬浮发生装置模拟3种风速条件下典型入湖河流河口沉积物再悬浮和沉降过程。结果表明,随着风速的增大,水柱中悬浮物总量增加;3种风速条件下氨氮（NH4＋-N）增量均为负;小风和中风过程,正磷酸盐（PO43--P）总量呈减小趋势,大风过程,正磷酸盐总量出现了明显上升,相对于初始值增加了46%,在5.1-8.7m/s的某一模拟风速条件下PO43--P的释放和吸附达到动态平衡,其表观值与初始值相等。总氮（TN）和总磷（TP）总量随着风速的增加而增大,TN最大增量是初始总量的2倍,而TP则是17倍;风浪过后TN、TP总量基本恢复到初始值。典型风速过程中,营养盐垂向分布无明显规律。

A Y-shape apparatus,which stimulates the resuspension-sedimentation process of indoor sediment,was deployed to study the resuspension and settlement process of sediments from the estuary of Tianji Port in Gonghu Lake under the influence of different wind strengths.More suspended substance（SS） will be released into the water with the increases of wind speed.The increment of ammonia nitrogen（NH＋4-N） is negative under the three types of wind.The gross of phosphate（PO3-4-P） exhibits a decreasing trend under the condition of light to moderate wind.The gross of PO3-4-P rises significantly under strong wind,about the increase of 46% compared to the initial value.The release and adsorption of PO3-4-P are dynamically balanced under a simulated wind condition between 5.1 m/s and 8.7 m/s,and an apparent value equals to the initial value.The gross of total nitrogen（TN） and total phosphorus（TP） increases as the wind strength gets stronger.Compared to the initial value,the increase of TN and TP can be as much as approximately 2 and 17 times,respectively.The gross of TN and TP almost returns to the initial value after wind stops.For the typical type of wind,the vertical distribution of nutrient shows not clear patterns.