| Along with the rapid development of coastal economy, the fast growth of population and the year-by-year increasing of discharged pollutant, offshore eutrophication is serious day by day, which is a world problem and seriously affects the offshore resources and the sustainable use of environment. Laizhou Bay locates in the north part of our country and has important ecology values. But in recent years, the environment of Laizhou Bay has been worsened day by day, the ecosystem function is seriously degenerated, and the resources are tended to dries up. It is indispensable to reinforce the research for the present environment situation and the pollution mechanism of Laizhou Bay and seek the controlling method of gross pollution to realize the resources and environment sustainable use. According to the above, the project team has implemented two investigations of marine environment present situation of Laizhou Bay separate in June and September 2001, and in this foundation, the project team calculates the permission quantity to dump pollutants, the reduced quantity and reduction rate of the main rivers flowing into the Laizhou Bay through the Laizhou Bay hydrodynamic process and the mechanism of pollutant proliferating simulation, unifying the Laizhou Bay function delimit.The main pollutant of Laizhou Bay is COD, the inorganic nitrogen (DIN) and the inorganic phosphate (DIP), the oil and the volatility phenol also exceed the standard and display space-time diversity. In June, the main pollutant is COD, the inorganic nitrogen and the volatility phenol, and they are mainly concentrates in the tip bay area. In September, the pollutant exceed the standard at varying degree in the entire area of Laizhou Bay, and the main pollutant are COD, the inorganic nitrogen, the inorganic phosphate, the oils, and the volatility phenol.. The environment of Laizhou Bay is running to further worse. The decrease of coastal rivers entering the sea causes the water salinity of Laizhou Bay to increase. The mean value of salinity of two investigations is 30.99, which is 2.81 higher than result of 1989's investigation (28.18). The average content of inorganic nitrogen is7.676μmolL-1, which was remarkably increased compared the investigation result (mean value 4.8μmolL-1) of Laizhou Bay in 1989. The nitrate nitrogen, the nitrite nitrogen and the ammonium nitrogen separately occupies 62.65%, 7.7% and 29.61% of the inorganic nitrogen in investigates in 2001. The mean value of the inorganic phosphate is 0.44μmolL-1, nearly 3 times to the investigation result (0.148(μmolL-1) on the same time of 1989. The mean value of the volatility phenol is 3.58μg.L-1, which is more than 3 times of the investigation result (mean value 1.1μg.L-1) in 1989. And although the COD has not obviously increased, it still maintained a higher level (mean value 1.5 mgL-1).The nutrient composition of Laizhou Bay water is seriously unbalanced. In 1995, N:P of Laizhou Bay is 92.32, in 1998 is 121.81, in June of 2001 is 82.44, in September of 2001 is 11.00. N and P are essential nutritional factors for the growth of sea phytoplankton, and the change of its proportion composition will directly affect to the structure and function of plankton ecosystem.The simulation of tide field value data of Laizhou Bay indicates that, the water of bay mouth region is quite active, and the water exchange capacity is stronger. The west and south inshore water is shallower, the velocity of flow is generally very weak, the water is delay, and the dilution and diffusivity is extremely weak. Therefore the storage capacity and transportation capacity of Laizhou Bay top region is quite low.The remaining current distributed situation of Laizhou Bay indicates that, at east bay mouth, the remaining current is strong, sea water exchange is quite active, and the physical self-cleaning ability of water body is stronger. Other waters, is generally weakly, especially in the bay top. The remaining current is terribly weak, which is extremely disadvantageous to the transportation and diffusion of pollutant d... |
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