台湾海峡西北部平潭岛海域表层沉积物中底栖有孔虫分布及其环境控制因素

对台湾海峡西北部平潭岛海域337个站位表层沉积物中底栖有孔虫进行分析鉴定,结果表明底栖有孔虫丰度、分异度变化较大,所出现的属种类型以玻璃质壳体为主,其次为瓷质壳,胶结壳最少。底栖有孔虫分布受水深、盐度、底质类型、底流和沿岸上升流等因素共同影响。应用‘PAST’软件的因子分析结果表明,该海域底栖有孔虫可划分为四个组合:组合Ⅰ(Hanzawaia-Pseudorotalia-Bolivina)主要分布于水深大于20m的深水区,受水深和底流影响明显;组合Ⅱ(Ammonia beccarii-Elphidiumspp.)主要分布于近岸浅水环境;组合Ⅲ(Quinqueloculina-Ammonia annectens-Spiroloculina)主要分布于海湾内高盐度区,推测受到沿岸上升流影响;组合Ⅳ(Elphidium advenum-Ammonia annectens)分布于组合Ⅰ与组合Ⅲ之间的局部区域,可能受浙闽沿岸流影响较强。

BENTHIC FORAMINIFERAL DISTRIBUTION IN SURFACE SEDIMENTS OF THE NORTHWEST TAIWAN STRAIT NEAR THE PINGTAN ISLAND AND ITS ENVIRONMENTAL CONTROLLING FACTORS

The benthic foraminiferal(BF)distribution in 337surface sediments taken from the northwest Taiwan Strait near the Pingtan Island in Fujian province has been quantitatively analyzed.The results show that the BF abundance and simple diversity varies in different samples and the BF composition is mainly composed of hyaline tests,followed with porcelaneous tests and small amount of agglutinated tests.BF distribution is controlled by complex factors including water depth,salinity,sediment size,bottom currents and alongshore upwelling current.Four assemblages have been identified based on the factor analysis.AssemblageⅠ(Hanzawaia-Pseudorotalia-Bolivina)is distributed in the area with the water deeper than 20meters and mainly influenced by the water depth and bottom water current; AssemblageⅡ(Ammonia beccarii-Elphidium)occurs in coastal transitional area with low salinity;AssemblageⅢ(Quinquiloculina-Ammonia annectens-Spiroloculina)dominates the central bay area,influenced by the strong alongshore upwelling current;AssemblageⅣ(Elphidium advenum-Ammonia annectens)is restricted within some local area between the assemblagesⅠandⅢ,and possibly related to the Zhemin coastal current.