夏、秋季北黄海营养盐的时空分布特征及其影响机制

摘要

Based on the cruises carried out in the North Yellow Sea in July 2011(summer) and October 2011(autumn),spatial and temporal distribution and influence factors of nutrients were discussed.The mean concentrations of nutrients in summer and autumn in the North Yellow Sea were respectively NO3 (1.57±1.71) and (5.93±3.84) μmol/L,NO2-(0.22±0.18) and (0.88±0.93) μmol/L,PO43-(0.22±0.13) and (0.40±±0.23) μmol/L,Si(OH)4 (4.98±2.23) and (6.71±3.24)μmol/L,NH4+ (1.35±0.90) and (1.23±0.69) μmol/L.NO3-accounted for 49％ of dissolved inorganic nitrogen in summer and 74％ in autumn.The concentrations of nutrients in the surface layer in coastal areas were higher than that in the middle of the sea in both spring and summer,the concentrations of nutrients in the bottom layer were higher than that in the surface layer,the concentrations among the cold water mass area were high.For each transect,influenced by cold water mass and water exchange,the stratification of nutrients was obvious and the concentrations increased from the surface to the bottom.N/P,Si/N and Si/P ratio were higher in coastal areas than that in the middle of the sea in both the surface and the bottom,and the nutrient limiting phytoplankton growth was phosphorus in summer.%基于2011年7月(夏季)和2011年10月(秋季)北黄海海域2个航次的调查资料,对北黄海夏、秋季营养盐的时空分布特征及其影响机制进行了探讨.结果表明,夏、秋季北黄海营养盐的平均浓度分别为:NO3-(1.57±1.71),(5.93±3.84).μmol/L,NO2-(0.22±0.18),(0.88±0.93)μmol/L,PO43-(0.22±0.13),(0.40±0.23)μmol/L,Si(OH)4 (4.98±2.23),(6.71±3.24)μmol/L,NH4+(1.35±0.90),(1.23±0.69) μmol/L,夏、秋季北黄海NO3分别占溶解无机氮的49％和74％.2个季节近岸海域表层营养盐浓度均高于中部海域,底层浓度高于表层,高值区是冷水团区.各断面营养盐的垂直分布层化现象明显,受冷水团以及水体交换混合的共同影响,浓度由表至底逐渐升高.夏、秋季表底层N/P、Si/N和Si/P比值的水平分布为近岸海域高于中部海域,且夏季北黄海浮游植物的生长繁殖受磷限制.