中国南海表层沉积硅藻的分布及其与环境关系探讨

Diatom Distribution in Surface Sediments and Its Relation With Environment in the South China Sea

通过对中国南海62个站位表层沉积硅藻的分析,查明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(包括变种和变型),以热性外洋种为优势,伴有一定量的近岸广布种。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。根据表层沉积硅藻中具有指示意义的硅藻种的分布和生态变化,划分6个硅藻组合带,各组合分别反映不同的海洋环境,其分布主要受到海洋环流的影响,表现为黑潮暖流、印度洋暖水的入侵以及沿岸流对南海表层沉积硅藻分布的影响。与南海相邻海区硅藻种类比较结果表明,研究海区表层沉积硅藻种类组成与临近的菲律宾海域相似程度最大,其次是中国东海海域、太平洋东北部海域。

The characteristics of diatom composition and distribution were investigated through analysis of sixty-two surface sediment samples in the South China Sea. In total, 235 species belonging to 56 genera were indentified. The dominant groups were the tropical oversea species Coscinodiscus nodulifer, Roperia tesselata,Coscinodiscus africanus etc. accompanying certain amount of common coastal species. The abundances of diatom exhibited an increasing trend from littoral to deep sea basin area on basis of index species distribution and ecological variation. Six diatom assemblage zones were characterized and each zone reflecting a different ocean environment. These zones were mainly influenced by oceanic current patterns in the region, such as the Kuroshio currents, the intrusion of Indian oceans warm water and the coastal currents to diatom in surface sediments of the SCS. It showed that the composition of diatom in this area was more similar to that in neighboring Philippines area followed by those in the East China Sea and northeast region of the Pacific Ocean.