象山港网箱养殖对水域环境的影响

根据2010年全年共6个航次对象山港网箱养殖区水域环境的监测结果,分析讨论了网箱养殖区DO、pH和营养盐的含量变化特征,并采用营养状态指数法和有机物评价指数法对该海域水质状况进行了评价。结果表明:DO和pH均符合《海水水质标准》(GB 3097—1997)规定的养殖海水Ⅱ类水标准;养殖区DIN全年含量变化范围分别为0.726～1.133 mg/L,其中NO3-N占无机氮的74.83%,是象山港网箱养殖区DIN的主要存在形式;DIP和SiO3-Si全年含量变化范围分别为0.043～0.082 mg/L和0.794～1.357 mg/L。DIN、DIP年均含量均超出《海水水质标准》(GB 3097—1997)规定的养殖海水Ⅱ类水标准。调查网箱区N/P平均值为34.02,可见养殖水体呈现氮过剩状态。根据营养状态指数(E)和有机物评价指数(A)的评价显示,水体呈严重富营养化状态,且有机物污染严重。

Effect of fish cage culture on water environment in Xiangshan Harbor

On the basis of investigation data observed at the fish-cage culture area for 6 cruises in 2010,variation characteristics of DO,pH and nutrients in fish-cage culture areas of Xiangshan Harbor were analyzed.The result indicated that the DO(dissolved oxygen) and pH complied with the Grade Ⅱ in "Seawater Quality Standard"(GB 3097—1997).The range concentration of inorganic nitrogen was 0.726-1.133 mg/L,the concentration of NO3-N accounted for 74.83% of DIN and was the main form of inorganic nitrogen in the fish-cage culture area.The range concentration of inorganic phosphorus and silicate were 0.043-0.082 mg/L and 0.794-1.357 mg/L,respectively.The concentration of inorganic nitrogen and inorganic phosphorus were too high to satisfy the Grade Ⅱ of "Seawater Quality Standard"(GB 3097—1997).The ratio of N to P was 34.02,so N was relative surplus.According to the value of eutrophication index(E) and organic pollution index(A),the seawater was in eutrophication state,and the organic pollution was quite serious.