The Study On The Exchange Fluxes Of Nutrients At The Sediment-Water Interface In Bohai Bay

The eutrophication and pollution of Sea-bay and coastal water is prevalent due tohigh speed development of the economy. Serve as the source and convergence ofnutrients, sediments play an important role in the budget and dynamical recycle ofnutrients in the water column. Therefore, an in-depth study on the exchange fluxes ofnutrients at the sediment-water interface and its contribution to the water column hasgreat significance concerning the control and treatment of the eutrophication andenvironmental protection.3 typical period laboratory incubation experiments were carried out to study theexchange fluxes of nutrients between sedimens and water at 4 stations of BohaiBay .In this paper, the obtained exchange fluxes of dissolved nutrients in aerobic andanoxic situations were listed. And it also drawled the conclusion that the exchangeflux of nitrite, ammonia and active silicate is affected slightly by the change of theoxidation-reduction environment, while the exchange flux of the nitrate in oxidativeenvironment is larger than that in reductive environment and for inorganic phosphatethe characteristic is opposite.A 2D water quality model which is based on the basic landform of Bohai area hasbeen set up. This model has two sub-models: one is hydrodynamic model and theother is convection-diffusion model, where the exchange fluxes of nutrients atsediment-water surface is considered as a variable only relates to the concentration ofthe water column.In this paper, numerical simulation is conducted using the 2D water quality modelto study the impact of the exchange fluxes of nutrients at sediment-water interface inBohai Bay. By comparing the simulated data with the field survey data, thecontribution of the exchange fluxes of nutrients to the water column is gained, whichshows that the nutrients in the sediments are very important, which largely affect thenutrients in the whole water column. And it is therefore an important factor toconsider in the prevention and treatment of coastal eutrophication.