Study On The Law Of Organic Phosphorus Release From Differents Sediment Terrain In Shallow Waters

Phosphorus is one of the essential biogenic elements which form the primary productivity in water bodies and the food chain.It is also a key factor that confines the eutrophication in lakes.Soluble organic phosphorus(SOP)constitutes a crucial link in the circulation of nutrients and the life process in shallow waters.SOP takes up at most 50-90% total phosphorus(TP)in lakes which are suffering severe organic pollution.Supported by the project of Natural Science Foundation of China ?transformation process and critical control factor of organic phosphorus in multiphase micro-interface under wave field?,this paper used the sediment from Yunying Lake as the research object,and simulated the wave which destabilize shallow lakes,in order to study the migration and release features of SOP from the sediment.The tests focused on the wave flow of different intensity and its effect on the release of SOP from the sediment.Meanwhile,hydrostatic pressure,the effect of the particle size of sediment and the landform(sediment laying method)on the SOP release was also researched.Tests results are as follows:With flat-surfaced sediment,the law of organic phosphorus in different water depth condition test group were similar under the static conditions,and the release of the SOP was rapidly rising,eventually reached dynamic equilibrium in 20 h.Compared with hydrostatic water depth,the equilibrium concentration of organic phosphorus were Q15cm>Q5cm>Q10cm>Q20cm.With undulating terrain,test group of 5cm,10 cm,15cm and 20 cm took samples in the center point,the wave crest and trough location,sampling points at 10 h reached maximum value,after entering a state of dynamic balance,which the middle,wave crest and trough organic phosphorus equilibrium concentration respectively: 0.305mg/L,0.253mg/L,0.325mg/L.The lowest terrain(valley)organic phosphorus equilibrium concentration was maximum,the highest point(peak)was minimum.Application of elovich equation fitting to organic phosphorus concentration change in the overlying water,compared with undulating terrain and flat terrain,at the same time,the release rate of the SOP in two experimental groups were decreasing,and before reaching equilibrium,the center point and the highest point in rugged terrain organic phosphorus released rate greater than the sediment tile in the experimental group,and minimum tile position test a larger group.Equilibrium was reached,flat and bottom bed were the lowest and the highest point of the sediment organic phosphorus release rate : V the height >V flat >V the lowest.At the same time,the final organic phosphorus release amount was roughly: Q flat bottom bed >Q ups and downs in bed.Two experimental groups were analyzed and compared,hydrologic terrain sampling point organic phosphorus equilibrium concentration was smaller than the tiling corresponding to the location of sampling points,terrain change reduced the release of organic phosphorus.In different intensity of wave,the organic phosphorus concentration in peak and valley of undulating terrain were increased with times going by.The concentration of organic phosphorus increased with the increasing of wave intensity in the bottom bed near the bottom area of 0cm,and the organic phosphorus concentration in C5 cm was compared with the wave intensity as follows: Q8cm>Q14cm>Q5cm.The organic phosphorus concentration of 0cm,5cm and 15 cm sampling points in the bottom bed ware compared with the wave intensity: Q14cm>Q5cm>Q8cm.