Taphonomic bias in the transition from life to death assemblages of marine phytoplanktor

代表一个沉积物捕集间隔的四组时间序列，由十三个连续的27至28天的样本组成（1991年3月5日~ 1992年3月2日）在西北太平洋JT站的4个不同深度采集了10个样品（34 <$9.802 'N，141 <$59.268' E; 916 m，3422 m，5429 m和8430 m），为评价硅藻从生到死的组合转变过程中的信息损失提供了材料。两个沉积物样品也提供了材料，以评估沉积物-水界面上的损失。对比四套圈闭样品的通量记录，在3442 m和5429 m两个不同深度发现了一个通量高期，作为显著的通量峰值。硅藻通量的下沉速度是由两个峰值之间的时间差计算出来的，大于71米/天。两个峰和下伏沉积物中硅藻组合的差异表明，沉积物-水界面上的溶解作用是决定沉积物中硅藻组合的主要因素，黑潮水体中最易受溶解作用影响的硅藻类群有：双头菱形藻-双叉菱形藻复合体、印度新翠雀鲷和角毛藻。这些形式共同构成了55%至60%的总沉积物陷阱植物区系，这表明从水柱到沉积物的信息损失至少为50%。

Four sets of a time-series of thirteen consecutive 27 to 28 days-long samples representing one sediment trapping interval (Mar. 5,1991-Mar. 2,1992) were collected from four deferent depths in the northwest Pacific at station JT (34ﾟ9.802'N,141ﾟ59.268'E ; 916m, 3422m, 5429m and 8430m), and provided material to evaluate information loss in the transition from life to death assemblages of diatoms. Two sediment samples also provided material to evaluate the loss on sediment-water interface. Comparison in flux records among the four sets of trap samples distinguishes one high flux period found in two different dephts as conspicuous flux peaks ; 3442m and 5429m. A sinking velocity of diatom flux is calculated from a time lag between the two peaks ; more than 71m/day. Differences in diatom assemblages among the two peaks and the underlying sediments suggest that dissolution on sediment-water interface appears to be the prime factor in determining diatom assemblages preserved in sediments, and the following three diatom groups are distinguished as most susceptible forms to value dissolution in the Kuroshio water ; Nitzschia bicapitata-bifulcata complex, Neodelphineis indica, Chaetoceros species. These forms together comprise 55% to 60% of total sediment-trap floras which suggests that information loss from water column to sediments is at least 50%.