唐岛湾网箱养殖区水体氮、磷含量特征及潜在性富营养化评价

根据2004年8月～2005年5月4个航次对唐岛湾网箱养殖区海水营养盐(NH4 -N、NO3--N、NO2--N和PO34-P)含量的监测结果,分析讨论了其含量变化特征,并利用一种新的富营养化评价模式,评价了唐岛湾的潜在性富营养化程度。结果表明,网箱养殖区水体中的氮、磷营养盐含量随养殖进程呈现不同的季节变化规律,受网箱养殖活动和浮游植物生长状况的综合调控;养殖区N/P值的年平均值为46.45,表明网箱养殖区水体缺磷,春、秋、冬季都以磷为浮游植物繁殖生长的限制因子,春季尤为严重。潜在性富营养化评价结果为:除春季达到磷限制中度营养水平外,其他季节均处于贫营养水平,表明该养殖区的营养水平较低,水质质量较好。

Analysis of nitrogen and phosphorus contents with assessment on potential eutrophication in the net-cage culture area in Tangdao Bay

On the basis of investigation data during 4 cruises from August 2004 to May 2005,variation characteristics of inorganic nitrogen(NH 4-N,NO-3-N,NO-2-N)and phosphorus(PO3-4-P)in net-cage culture areas of Tangdao Bay were analyzed.The eutrophication degree in Tangdao Bay was assessed with the potential eutrophication assessment model.The results showed that the contents of inorganic nitrogen and phosphorus varied with seasons,being mainly regulated by the cage culture activities and phytoplankton growth status.The annual average value of N/P was 46.45,indicating that phosphorus was deficient in the net-cage culture areas.Assessment on potential eutrophication revealed that the water quality was oligotrophic in summer,autumn and winter,and was in the state of medium-nutrient with limited phosphorus in spring.