【摘要】 为研究营养盐在东海大规模赤潮形成过程中的作用,分别于2004,2005年春季在东海赤潮爆发前进行了2个航次的海上调查。调查结果显示:DIN,PO4-P,SiO3-Si浓度分别高达15,0.55,15μmol.L-1以上,调查海域整体上处于富营养化状态;受陆源输入影响,调查区域营养盐分布呈现出近岸高、外海低,等值线走向与岸线基本平行的特点。同2004年相比,2005年春季调查海域营养盐高值区明显外扩,营养盐水平整体升高:其中DIN浓度升高9%、PO4-P升高18%、SiO3-Si升高60%,硅磷比上升60%,硅氮比上升了47%。研究结果表明,较高的营养盐浓度水平,较高的硅酸盐含量以及较高的硅磷比、硅氮比值是2005年春季优先爆发大规模硅藻赤潮的重要原因之一。更多还原

【Abstract】 To understand the nutrients impact at prophase of large scale Harmful Algal Blooms(HAB) in the East China Sea(ECS),two cruises were conducted in the frequent HAB areas of the ECS in spring,2004 and 2005.Based on the nutrients data from the cruises,the nutrients concentrations,distribution and variation in the two years were discussed.The results show that the study areas were at a status of eutrophication and the concentrations of DIN,PO4-P and SiO3-Si were higher than 15 μmol·L-1,0.55 μmol·L-1and 14 μmol·L-1,respectively.Mainly influenced by the terrestrial input,the nutrient distribution had a clear characteristic that the nutrients’ contours nearly paralleled with the coastline and decreased rapidly in the offshore direction.Compared with the condition in 2004,the area in eutrophic condition was widely expanded,and the nutrient concentration was wholly increased: the concentration of DIN increased 9%,PO4-P increased 18%,SiO3-Si increased 60%,the ratio of Si/P increased 60% and the ratio of Si/N increased 47%.It was concluded that a higher nutrients’ level,higher silicate content,and higher Si/P and Si/N ratios were the main factors for inducing large scale diatom HAB in the Spring of 2005.更多还原