南海赤潮的时空分布特征及其与南海环境关系的综合分析

Analysis of harmful algal blooms associated with ocean environments in the South China Sea

利用历史数据和卫星观测,系统分析20多年来(1980年-2003年)在南海海域发生的赤潮事件与环境特征,详细比较赤潮在南海四大区域(北部、东部、南部和西部海区)的区域分布、多发藻种和季节变化等特征。研究结果表明南海海域赤潮发生具有以下特点:(1)区域性:赤潮多发区域集中在珠江口附近(中国),马尼拉湾和马辛洛克湾(菲律宾)和沙巴州的西海岸(马来西亚);(2)季节性:在北部海区,赤潮的发生时间主要集中在3-5月份,东部海区在5-7月份,西部海区在7月份,而南部海区在全年都会发生;(3)藻种差异性:主要赤潮藻种在北部海区是夜光藻(Noctiluca scintillans),东部海区和南部海区是扁甲藻(Pyrodinium bahamense);(4)年际变化:不同海域赤潮的多发年份不同,对于整个南海而言,1991-1998年是赤潮的多发年。赤潮发生受到环境条件的影响,如季风、河流的排放、上升流、以及沿岸海域水体富营养化。

Harmful algal blooms（HABs） in South China Sea（SCS） showed regional,seasonal and annual characteristics,as well as the difference of causative algal species.Areas with frequent HABs included the Pearl River Estuary（China）,the Manila Bay（the Philippines）,the Masinloc Bay（the Philippines）,and the western coast of Sabah（Malaysia）.HABs occurred frequently during March-May in the northern region of SCS,May-July in the eastern region,July in the western region,and year-round in the southern region.Among the species that cause HABs in SCS,Noctiluca scintillans dominated in the northern region,and Pyrodinium bahamense in the southern and eastern regions.Both P.bahamense and N.scintillans were the dominant species from 1980 to 2003.Some species not previously recorded formed blooms during 1991-2003,including Phaeocystis globosa,Scrippsiella trochoidea,Heterosigma akashiwo and Mesodinium rubrum.Variations in HABs are related to various regional conditions,such as a reversed monsoon wind in the entire SCS,river discharges in the northern area,upwelling in Vietnam coastal waters during southwest winds and near Malaysia coastal waters during northeast winds,and eutrophication from coastal aquaculture in the Pearl River estuary,Manila Bay and Masinloc Bay.