秋季莱州湾及附近水域营养现状与评价

根据2004年10月对莱州湾水域调查结果,分析并评价了莱州湾水域秋季营养状况.结果表明,由于受黄河和小清河人海径流的影响,表层无机氮、磷酸盐和硅酸盐水平分布均表现为湾西部和西南部含量较高于其他水域.而底层分布却不尽相同,无机氮为湾南部近岸水域含量较高;磷酸盐为湾东部近岸水域含量较高;硅酸盐为除湾口外水域水平梯度较大外,整个湾内水域分布相对较均匀.从水域环境质量评价结果看,N/P比值较大于Redfield比值,P显得相对缺乏.与Justic和Dortch等提出的营养盐化学计量限制标准比较符合硅限制条件.根据营养化评价模式和有机污染指数计算结果,2004年秋季莱州湾水域营养水平基本属于磷限制中度营养水平,有机污染程度属2级,表明该水域开始受到有机污染.

Status and evaluation on nutrients in Laizhou Bay in Autumn

The nutrient status was analyzed in Laizhou Bay in autumn, according to the investigating result in Oct. 2004. The results shown that the horizontal distributions of inorganic nitrogen, phosphate and silicate at surface layer was higher in west and southwestern waters than in other waters, because of the effect of runoff of Yellow river and Xiaoqing River. The horizontal distribution was not alike in bottom layer, the content of inorganic nitrogen was relatively high in alongshore waters of west, the content of phosphate was relatively high in alongshore waters of east and the silicate was relatively even in Laizhou Bay besides the bay mouth waters. From the evaluation result, The N/P ratio was higher than Redfield ratio. The phosphate was limit factor for the growth of phytoplankton, and compared with limit standard of chemical measure for the nutrient salts, it accorded with the limit condition of silicate. According to the evaluation mode of eutrophication and the organic pollution index, it is the middling phosphorus limit nutrient level in autumn 2004, basically, and the organic pollution degree remained the second level.