【摘要】 通过对取自南海62个站位的表层沉积物样品,进行了硅藻、沉积物粒度分析,查明了研究海区硅藻的种类组成及分布特点,共鉴定到硅藻56属的235个种和变种、变型.种类以热带外洋种为优势,如Azpeitia nodulifer、Roperia tesselata、Azpeitia africanus、Hemidiscus cuneiformis、Nitzschia marine等,伴有一定量的热带—亚热带近岸种和广布种如Paralia sulcata、Thalassiosira excentrica、Cyclotella stylorum、Thalassionema nitzschioides、Thalassiothrix longissoma等.总体上,南海硅藻丰度变化呈现从陆架向陆坡至海盆递增的趋势.研究海区硅藻种类组成与临近的菲律宾海域相似程度最大,其次是东海、太平洋东北部海域.对影响南海表层沉积硅藻分布的主要因素进行了探讨,南海表层沉积硅藻主要受海底地质地貌、沉积速率、水动力条件和水文气候条件等的影响较大,硅藻的分布往往是这些因素综合作用的结果.更多还原

【Abstract】 Sixty-two surface sediment samples,diatom and grain size in the South China Sea were analyzed.The recent diatom faunal,distribution character and modern marine environment are discussed.Diatom in the surface sediment shows rich diversity.In total,235 species belonging to 56 genera were indentified.The dominant groups are: Azpeitia nodulifer,Roperia tesselata,Azpeitia africanus,Hemidiscus cuneiformis,Nitzschia marine,Paralia sulcata,Thalassiosira excentrica,Cyclotella stylorum,Thalassionema nitzschioides,Thalassiothrix longissoma,etc.The hot water species Azpeitia nodulifer is the most dominant species in the surface sediment.The distribution pattern of diatoms reflected the difference of environmental conditions.The concentration of diatom in surface sediment varied in different area,the abundance of diatom frustule increased sharply from littoral to deep sea basin area.It showed that the variety of diatoms in this sea area is most similar to that in neighboring Philippines by contrast with the South China Sea,next come the East China Sea and northeast of the Pacific Ocean.Diatom distribution in surface sediment was influenced by submarine gemorphology,hydrodynamics,deposit speed and hydroclimate,etc.When studying paleoceanographical environments and paleoclimate variations,we need to think about all these environment factors that control the distribution of diatom.After dissolution,transfer,sediment and settlements,diatom from sediment can reflect the composition of planktonic diatom groups partially.更多还原