长江口和杭州湾海域生物生产力锋面及其生态学效应  

Biological productivity front in the Changjiang Estuary and the Hangzhou Bay and its ecological effects

作　　者：宁修仁[1] 史君贤[1] 蔡昱明[1] 刘诚刚[1] 

机构地区：[1]国家海洋局第二海洋研究所

出　　处：《海洋学报》2004年第6期96-106,共11页

摘　　要：通过分析海洋生态学资料并结合卫星遥感、渔场及赤潮等资料,发现长江口和杭州湾及其毗邻海域生物生产力的锋面,在离长江口门和杭州湾口约100km的长江冲淡水中部海域出现蓝细菌丰度、浮游植物现存量和初级生产力以及浮游动物的最大值,该锋面的存在和位置被水色遥感所确认.光和营养盐在此呈现最佳的权衡.在该锋区悬浮体浓度小于5mg/dm3,盐度为25～30.在该锋面的西侧高的悬浮体浓度造成了浮游植物的光限制,其东侧距长江口和杭州湾口较远,陆源营养盐被稀释,加之浮游植物的消耗,造成了营养盐的限制.夏季水体的层化,增强了水体的垂直稳定,使这种分布格局更加显著.由于细菌多附着在悬浮颗粒物的表面,细菌丰度的最大值出现在近口门区的最大浊度带,在向外海方向随着悬浮体的沉降细菌丰度迅速降低.在生物生产力锋面,浮游植物的旺发导致水体跃层之上高溶解氧浓度和低营养盐浓度,尤其是PO4被耗尽,同时浮游动物饵料的丰富,造成浮游动物旺发;由于蓝细菌的快速增殖,其流式细胞测定的细胞粒径变小.生物生产力锋面的出现产生了显著的生态学效应,一方面造成某些经济鱼类产卵和索饵场的形成,例如鲐鱼、马鲛鱼等;另一方面造成赤潮多发区和底层水缺氧区.Through analyzing of multidisciplinary oceanography data of a clear spatial zonation of the parameters and a primary productivity front are found in the study areas.In the turbid river mouth phytoplankton biomass and productivity are low,although the concentrations of nutrients,e.g,NO^-_3,PO^(3-)_4,etc.are high,but bacteria are active.On offshore-ward,phytoplankton biomass and productivity increase gradually with suspended solids(SS)settling out.The maxima of phytoplankton parameters occur at about 100 km away from the river mouth and the east-side of Zhoushan Archipelago,where SS concentration is less than 5 mg/dm^(3) and salinity 25～30,which results in high concentration of dissolved oxygen,depletion of nutrients,particularly PO^(3-)_4 in the upper layer and the dominance of young Synechococcus cells with smaller size,due to their fast growth there.The front of zooplankton biomaas is resulted from the abundant phytoplankton,as its food.On far offshore,the above phytoplankton parameter values decrease rapidly,due to the nutrient limitation and probably also zooplankton grazing.The critical factor responsible to the biological productivity front in the study areas increases in light availability following SS sedimentation,which is accelerated by the water stratification.The biological productivity front has been confirmed by ocean color (CZCS)of the satellite remote sensing.It results in important fishing areas where several commercial fishes,such as Spanish mackerel,squids,mackerel and scads,etc.are for spawning and feeding,and also result in the frequent occurrence zones of harmful algae bloom and red tide,as well as a hypoxic zone underneath the biological productivity front.

关 键 词：生物生产力锋面 浮游植物 生态学效应 赤潮 长江口和杭州湾 

分 类 号：Q178.53[生物学—水生生物学]