浒苔绿潮与苏北近岸海域营养盐浓度的关系研究

根据2010年3～6月5个航次对苏北近岸浒苔绿潮暴发区海域进行的调查数据,研究了该海域营养盐的浓度变化和分布特征.结果表明,受陆地径流和苏北沿岸流的影响,调查海区为营养盐高值区,为绿潮暴发提供了一定基础.溶解性无机氮(DIN)、磷酸盐(PO34--P)和硅酸盐(SiO23--Si)最高浓度分别为23.04、0.55和15.85μmol.L-1,春季浮游植物生命活动旺盛和浒苔绿潮对营养盐的吸收导致从第一至第五航次硝酸盐(NO3--N)、磷酸盐(PO34--P)、硅酸盐(SiO23--Si)和溶解性无机氮(DIN)整体呈下降趋势.此外,水体中N/P与浮游生物体中N/P越接近越有利于浮游生物生长.第四和第五航次的N/P比值比较有利于浒苔的生长.各航次营养盐的分布特征均表现为近岸高,远岸低的趋势.

Variation of Nutrient Concentrations at the Inshore Coastal Area of Northern Jiangsu Province and the Occurrence of Green Tide Caused by Enteromorpha prolifera

Based on the investigation of the inshore coastal area of northern Jiangsu province with occurrence of green tide caused by Enteromorpha prolifera,which was performed in five voyages during March to June 2010,the variation of nutrient concentrations and its distribution characteristics were studied in this paper.The results showed that the concentrations of nutrients were relatively high in this region due to the terrestrial runoff and northern Jiangsu coastal current,which contributed to the outbreak of green tide.The highest concentrations of dissolved inorganic N(DIN),PO3-4-P and SiO2-3-Si were 23.04,0.55 and 15.85 μmol·L-1,respectively.In spring,due to the strong life activities of plankton and the intake of nutrients by green tide,the concentrations of NO-3-N,PO3-4-P,SiO2-3-Si and DIN all showed a tendency of decreasing from the first to the fifth voyage.Besides,the closer the N/P ratios in water and in the body of plankton,the faster the plankton grows.The N/P ratios measured in the fourth and fifth voyages were relatively favorable for the growth of Enteromorpha prolifera.The distribution characteristics of nutrients had a tendency of decreasing from inshore to offshore in all voyages.