南海表层沉积沟鞭藻孢囊的分布特征

DISTRIBUTION OF DINOFLAGELLATE CYSTS IN SURFACE SEDIMENTS FROM SOUTH CHINA SEA

为研究沟鞭藻孢囊含量和组合的分布规律 ,分析了南海 38个站位的表层沉积样品。共鉴定得沟鞭藻孢囊 1 6属 2 7种 ,孢囊含量变化在 8至 92 5粒·g- 1 之间。研究区北部及靠近巴士海峡的样品孢囊含量较高 ,而南海南部的样品孢囊含量较低。孢囊含量的这一分布型式与南海表层水中浮游植物的分布特征具有一致性 ,似受表层海水营养因素控制。Spiniferites是沟鞭藻孢囊组合的优势组分 ,主要有S .ramosus,S .hyperacanthus,S .mirabilis等。孢囊组合中其它较重要的属种包括Impagidinium ,Operculodiniumcentrocarpum ,Polysphaeridiumzoharyi,Lingulodiniummachaerophorum ,Protoperidinium孢囊和Tuberculodiniumvancampoae。Spiniferites和Impagidinium的含量从陆坡往深海有增多之趋势 ,而其它类型则减少。

Surface sediment samples at 38 sites of the South China Sea were collected and analyzed to study the contents and assemblage distributions of dinoflagellate cysts. A total of 27 species(16 genera) are identified. The dinocyst contents range from 8 to 925 cysts per gram. The high values are found in the samples from the northern part of the research area and near the Bashi Strait, while the low ones in the southern part of the South China Sea. The distribution pattern of dinocyst con tents is concordant with that of the phytoplankton in the surface water of the South China Sea, which seems to be controlled by nutrient content of the surface water. The dinocyst assemblages are dominated by Spiniferites, mainly including S.ramosus, S. hyperacanthus and S. mirabilis. The other significant genera or species are Impagidinium, Operculodinium centrocarpum,Polysphaeridium zoharyi, Lingulodinium machaerophorum,Protoperidinium and Tuberculodinium vancampoae. The cyst contents of Spiniferites and Impagidinium show an increasing trend whereas those of others decrease from the continental slope towards the deep sea.