大亚湾网箱养殖区生物-化学特性与营养状况的周日变化

根据1998年11月对大亚湾大鹏澳网箱养殖区进行的定点24h连续水质监测资料,分析并讨论了该养殖区海水生物-化学各要素的垂直分布和周日变化规律,并用单项指标评价法和改进的营养状态质量指数(NQI)法,参照营养指数(E)对该网箱养殖区海水的营养状况进行了评价和研究.结果表明,各项要素的平均值大都是表层＞中层＞底层;周日变化主要受潮汐运动和海水中生物的节律性生理活动的综合影响;表层海水的富营养化率明显高于中层海水,其各单项指标处于中度一富营养状态,而中层和底层海水则分别处于贫一中度和贫-富营养状态;PO4-P相对较贫乏,为养殖区富营养化的最关键限制因素.

Daily Variations of Biological and Chemical Elements and Nutrient Status in the Net Cage Aquaculture Area in Daya Bay

Continuous survey was conducted in the net cage aquaculture area in Daya Bay for 24 h in November,1998. The vertical distribution and daily variation of the biological and chemical elements in the seawater were analyzed. In addition,the nutrient status was assessed by the single-item and the developed nutrient quality index (NQI) and eutrophication index (E).The results show that the average value of the key elements in the surface water were the highest,followed by that in middle level water,and that in the bottom-level water is the lowest;and the daily variation of the key elements were affected mainly by the tide and physio-activities of the organisms in the water.The eutrophication rate in surface water is higher than that in the middle level water significancely,and the single-items in the surface water were in middle-eutorphication status, those in the middle level and bottom water were in poor-middle and middle-eutrophication status respectively.The PO 4-P was in poor status, which was critical limited item for the eutrophication in the net cage aquaculture area.