| The eutrophication of water system is one of common ecological problem. The Three Gorges Reservoir started water storage in June 2003 and water level of the dam fluctuated around 135 meters. Since then, part of the Yangtze River became a typical channel reservoir, consequently, flow velocity of water in this area sharply decreased as hydraulic condition changed. Moreover, water level of the dam would finally reach up to 175 meters in 2009, and water flow velocity would decrease from 2 m/s to 0.25-0.5 m/s, which would seriously impair its transport and diffusion capacity for contaminants. With the same load of nitrogen and phosphor as well as the same discharge method, water quality of the Three Gorges Reservoir would definitely deteriorate. As another consequence, a series of factors resulted from damming, such as lower water flow velocity, higher transparence, depositon of suspended solid, higher water temperature, fewer foggy day and increased sunlight in winter, would be optimal for photosynthesis of aquatic plant, especially algae, which could potentially lead to eutrophication. Therefore, the structure and function of local aquatic ecosystem would be influenced by changing hydraulic condition.Along with the Changjiang River Three Gorges reservoir water eutrophication of water tributaries, as well as a growing outbreak How to effectively prevent and treat water-workers as the most important topic in today's environment. Among them, ecological model of the water is the important one. China's water, development, and demise of biological, chemical and hydrological effect of weather and other factors. The most important impact on the growth of algae in water natural nutrients, including nitrogen and phosphorus. To be able to find effective ways to control eutrophication of water bodies, the relationship between nutrients and algae growth has been the focus of study.According to different behaviors of nutrition at different medium layers would make obviously different effects on rate of algal growth in water system we established a new numerical model of the algae growth by considering these effects from various nutrition concentrations in water environment, on the surface and inside of algae cell,and especially the effect of adsorption/desorption of nutrition on the surface of algal cell. The validation of the model parameters are carried out by numerical iterative calculation with experimental data of literature, and computation results shown that the mean relative error between the actual measured values cited from literature and the numerical results of this model is less than 6.9%, furthermore, the maximum absolute values of cumulative relative error of the model and the original model which doesn't consider effect on adsorption/desorption of nutrition are 11.7% and 34.18% respectively. Obviously, the model would fit more well the actual measured data. The concentration of nutrition on the surface from the model computation shown the real change status of the algae absorb nutrition under alternate condition of light/dark, and at same time, the concentration varying of ATP inside algae cell would correlate to the concentration of nutrition in water environment and to the nutrition's condition of algae cell so that the cooperating relation between molecular layer and cell layer to have theory significance has been built.
|
PDF Full Text Request