Effects of sediment resuspension on nitrogen and phosphate exchange at the sediment-water interface in East Chongming Tidal Flat

Sampling sediment and water to mimic sediment resuspension and researching its effects on nitrogen and phosphate exchange at the sediment-water interface in east Chongming tidal flat. Through the experiment, it was found that sediment resuspension causes NO3(-)-N, NH4(+)-N, NO2(-)-N and DIP releases. The release of NO3(-)-N is most marked, the increasing concentration of NO3(-)-N, NH4(+)-N, NO2(-)-N and DIP reach in turns: 11.869 mumol.L-1, 2.1713 mumol.L-1, 0.2 mumol.L-1, 0.02 mumol.L-1. At the same time, resuspension also change nitrogen and phosphate exchange at the sediment-water interface compare to without resuspension to great extent. NH4(+)-N and NO3(-)-N have absolutely opposite diversification with and without resuspension; NO2(-)-N shows complicated transformation because of many effected elements. The result of the experiment display the changes of NH4(+)-N, NO2(-)-N and DIP concentration in water have good relation to SPM (mg.L-1), this relation have not appear in change of NO3(-)-N.