In The Yangtze Estuary Hydrodynamic Processes And Tn, Tp, Momentum Transport,

The environment of Yangtze estuary tidal flat is effected by the interaction of sea and land so that the effect of tide hydrodynamic is intensity and complex. Nitrogen and phosphor is the important element to the zoology system of tidal flat wetland. The plants cannot grow and reproduce well without them. However, the overmuch nitrogen and phosphor will result in water eutrophication. Under the effect of hydrodynamic, nitrogen and phosphor transport dynamically on the tidal flat and adsorb, release and exchange complexly with sediment. Some scholars in domestic and overseas pay much attention to the research of nutrition element's transportation and circulation on tidal flat. They make much beneficial explore from the view of earth chemistry. But the research of nutrition element's dynamical transportation effected by tide hydrodynamic is limited so it is the obstacle to set up the completed nutrition element's transportation, circulation model and also effects the evolution of substance circulation research on the estuary.The article is based on Nation Nature Science Foundation of China, " Biogeochemical Cycling of Pollutants in Complex Environments of Tidal Flats in the Yangtze Estuary" (No.40131020) . The author chose open tidal flat of Dong Tang Chongming Yangtze estuary as research object and set up typical section plane so that under the good condition, the author measured hydrology element, total nitrogen and total phosphor index. The author emphasized on the research of the process of tidal flat hydrodynamic and the process of total nitrogen, total phosphor dynamical transportation and got the conclusion as follows:(1) Open tidal flat of Dong Tang Chongming Yangtze estuary was chosen as research object and two typical section plane was set up in order to measure four seasonal hydrology element and get index datum such as water level, current direction, current speed. After analyzing, the author got the basic character of tidal flat hydrodynamic: the time of flooding on bare flat and ebbing is basically the same and the time of flooding on pioneer zone of salt marsh is a little short; the process curve of current speed on bare flat did not appear peak value on the beginning of flooding and at the end of ebbing but presented double peak, that is, it presented double peak in winter and spring and ebbing peak value disappeared in summer and autumn, salt marsh presented single peak character in a year and the process curve in tidal creek presented double peak; all current direction on every spot presented gyration current and the current speed changed rapidly during the high water level without obvious slack water period. The tide upright shore dominated at the area of fleet water.(2) The change of total nitrogen concentration wasn't obvious. The total nitrogen concentration of single tide degree and coming tide is almost the same. The average total nitrogen concentration of the south spot is between 1.07-2.80mg/l. The seasonal change of total nitrogen concentration wascontrolled by the nitrogen transportation of Yangtze runoff and it was a little more in summer and autumn but a little less in spring. The exchange of nitrogen between disordering tide and water-sediment interface effected total nitrogen concentration of overlying water. The violent disorder of flooding and ebbing resulted in the release of nitrogen in tidal flat sediment and overlying water so that total nitrogen concentration raised rapid on water surface. The hydrodynamic condition wasn't obvious so the nitrogen exchange controlled the change of total nitrogen concentration on overlying water. Total nitrogen instantaneous concentration, suspended sediment concentration and current speed hadn't obvious relativity and the number of grain nitrogen was very little(3)The change range of total nitrogen flux was very large. The flux in autumn was high than other seasons, it was the least in winter. Net flux was different on every spot and it was negative in summer spring tide on bare flat spot, nitrogen transported towards s...