大亚湾典型养殖区沉积物—海水界面营养盐扩散通量及其环境意义

Nutrients diffusion fluxes in sediment-water interface in marine culture area of Daya Bay and its environmental significance

通过2005年6月对大亚湾西部的大鹏澳养殖海域进行沉积物柱状样采集分析,探讨了间隙水中NH4-N、NO3-N、NO2-N和PO4-P含量及空间分布特征,估算了沉积物—海水界面营养盐的扩散通量。结果表明,网箱养殖区柱状样间隙水中NH4-N、PO4-P平均含量分别为325.3μmol/L、20.4μmol/L,远高于贝类养殖区及对照区。网箱养殖区NH4-N、PO4-P、NO2-N平均扩散通量在三个区域中均居首位,分别为692.9、36.5和6.1μmol/(m2.d),贝类区次之。网箱养殖大大提高了营养盐由沉积物向海水界面的扩散通量,使养殖海域成为一个极具潜力的污染内源。

The concentrations and spatial distribution characteristics of NH4 -N, NO3 -N, NO2- N and PO4-P in the sediment interstitial water in the marl-culture area of Daya Bay were analyzed. The results showed that the contents of NH4-N and PO4-P in the cage cul- ture area were 325.3 mol/L and 20.4 mol/L, respectively, which were higher than in the shellfish culture area and control area. According to Fick＇s first law,the average diffusion fluxes of NH4-N, PO4-P, NO2-N in the cage culture area were the highest and followed in the shellfish area, which were 692.9, 36.5, 6.1μmol/（ m^2·d）, respectively. The cage aquaculture greatly improved the interface fluxes diffusing from sediments to overlaying water, which could be a potential pollution source in the marine culture area.