长江口羽状锋海区底质中活有孔虫分布特征研究

Study of Distribution Characteristics on Living Foraminiferids in Surface Sediments of the Plume Front Area of the Changjiang Estuary

本文通过对采自长江口羽状锋海区４７个底质样品所做的活有孔虫定量分析表明；本海区活有孔虫在夏季和冬季的分布，与海相性强度及深度有关。活有孔虫个数稀少，主要分布在口门外．盐度低于５‰的沉积区未见有活有孔虫出现。冬季见有二个活有孔虫组合区，夏季见有三个活有孔虫组合区。文章讨论了活有孔虫分布与水深、盐度和温度等作用的相互关系．

The auther analyses quantitatively fourtye-seven surface sediment samples collected fromplume front of the Changjiang estuary in August and December 1988 for studing the distribution of living foraminifers. The result shows the number of the living foraminiferal fauna is rarefrom the east to the west. The living foraminifers distribute mainly outside the mouth, there absent living forandnifers when salinity loner than 5‰ The area can be divided into three zones according to the characteristics of living foraminifers in winter: Ⅰ. Living foraminifer barrenzone, Ⅱ. Ammonia beccarii var.-Nonionella jacksonensis, Ⅲ. Florilus decorus-Eggerellaadvena, corresponding to the regions with water depth of less than 10m, 10-20m and morethan 20m, respectively. In summer there are four zones: Ⅰ. Living foraminifer barren zone, Ⅱ.Ammonia beccarii var.-Cribrononion vitreum, Ⅲ. Nonionella jacksoneusis-Ammoniabeccarii var, IV. Florilus decorus-Eggerella advena, corresponding to the regions with waterdepth of less than 10m, 10-20m, 20-40m and more than 40m, respectively.