大亚湾海域春季营养现状分析与评价

Status and evaluation on nutrients in Daya Bay in spring

根据2007年4月对大亚湾海域调查结果,分析并评价了该海域春季的营养状况。结果表明,DIN为湾西部和中部含量较高,PO4-P为湾中部海域含量较高,SiO3-Si为澳头附近海域中部和核电站附近海域东南部含量较高;底层DIN、PO4-P和SiO3-Si水平分布均表现为澳头附近海域中部含量较高于其他海域;上覆水中DIN和PO4-P为整个湾内水域分布相对较均匀,而SiO3-Si为霞涌西南部近岸海域和核电站附近海域东南部含量较高。从营养结构看,与Redfield值和Justic等提出的营养盐化学计量限制标准比较符合N限制条件。根据修正后的营养状态指数评价模式和有机污染评价指数计算结果,2007年春季大亚湾海域营养水平属于贫营养水平,有机污染程度表层、底层属0级,而上覆水属1级,表明大亚湾海水水质良好。

The nutrient status was analyzed in Daya Bay in spring, according to the investigation result in Apr. 2007. The results shown that in surface, the content of inorganic nitrogen was relatively high in west and central waters, the content of phosphate was relatively high in central waters and silicate was relatively high in the center of Aotou waters and the southeast of Nuclear power plant. In bottom layer, the horizontal distributions of inorganic nitrogen, phosphate, and silicate were higher in the center of Aotou waters. In overlying waters, the content of inorganic nitrogen and phosphate was relatively even in Daya Bay, but silicate was relatively high in alongshore waters of southwest of Xiayong and the southeast of nuclear power plant. From the nutrition structure, the inorganic nitrogen was the limit factor for growth of phytoplankton, and compared with Redfield ration and limit standard of chemical measure for the nutrient salts, it is accorded with the limit condition of inorganic nitrogen. According to the amended evaluation mode of eutrophication and the organic pollution index, the water quality was oligotrophic in spring 2007, and the organic degree were the zero level both in surface and bottom, but it was the first level in overlying waters.