【作者】 张洁帆；

【导师】 陶建华；

【作者基本信息】 天津大学 ， 环境科学， 2007， 硕士

【摘要】 由于渤海湾沿岸经济的高速发展,海湾及近岸海域污染、富营养化的现象已经很普遍,沉积物作为上覆水体中营养盐重要的源和汇,对水体中营养盐的收支和营养盐的循环动力学以及水体富营养化具有重要的作用。因此深入研究这一典型海域的沉积物和水界面间营养盐交换的状况以及了解界面交换通量对水体营养盐浓度的贡献对控制和治理海湾富营养化、环境保护具有重要意义。本研究从06年5月～10月对渤海湾的6个站位采样,进行了沉积物和水界面间营养盐交换通量的测定,并进行了相关影响因素的实验室培养实验。得出了渤海湾交换通量的实测值以及不同海水环境下交换通量的实验值。实验结果显示,渤海湾沉积物大部分时间内是营养盐的源;硅酸盐界面交换通量值较大,且具有较强的季节变化;硝酸盐的交换通量在富氧条件下要高于贫氧条件下,随水环境pH值的增大而减小,随着水环境温度的升高而降低,在生物扰动作用下呈增大趋势;氨氮、磷酸盐和硅酸盐则呈相反变化趋势。建立了二维生态水动力学模型。该模型包括两部分:水动力学子模型和对流扩散子模型,其中对流扩散子模型将沉积物和水界面的交换通量作为源项,结合它与其他影响因素的关系,建立源项与水体浓度的函数关系式。为了了解渤海湾沉积物和水界面间营养盐交换通量对水体营养盐负荷的影响,本文利用建立的水质模型对其进行了数值模拟,将模拟的结果与实测浓度进行比较,得出各项营养盐交换通量对水体的贡献。结果显示渤海湾沉积物中营养盐对水体的影响是相当大的,在进行富营养化的防治和模型构建时,沉积物和水界面间营养盐通量必须作为其中一个重要因素有所考虑。更多还原

【Abstract】 In recent years, the economy has developed rapidly around the coastal zone of Bohai Bay. As a result, more and more wastewater has been discharged into Bohai Bay, and the eutrophication problem has become more serious. Sediment serves as the source and sink of nutrients, and plays an important role in the budget and dynamics of nutrients recycling in the marine water. Therefore, a study on the exchange fluxes of nutrients between bottom sediment and water layer in this typical sea area is necessary, it has great significance for the eutrophication control and environmental protection.The nutrients exchange flux between bottom sediment and water layer at 6 stations in Bohai Bay was studied in this paper form May to Oct in 2006, and the lab incubation method was adopted to simulate and measure the nutrients exchange flux under different conditions in order to study the effect of related factors. It turned out that the sediment served as the source of nutrients in Bohai Bay in most part of the time.The exchange flux of SiO32- was higher and had a stronger variation with season, the exchange flux of NO3- was higher in aerobic situation than in anoxic situation, reduced when pH or temperature of the water went higher, and had an increasing trend under the function of bioturbation while NH4+, SiO32- and PO43- just went the other way round.A 2D ecohydrodynamic model of Bohai area has been set up. This model has two sub-models: one is hydrodynamic model and the other is advection-diffusion model, where the nutrients exchange flux between bottom sediment and water layer is considered as the source of the advection-diffusion model, which relates only to the concentrations in the marine water.In this paper, numerical simulation of the nutrients exchange flux between bottom sediment and water layer at Bohai Bay was conducted using the 2D ecohydrodynamic model. By comparing the simulated data with the measured data, the contribution of the nutrients exchange flux to the marine water was gained, which showed great importance of sediment nutrients in controlling the nutrient distributions and concentrations in the whole marine water. Therefore, it is an important factor to consider in the prevention of coastal eutrophication and the model construction.更多还原