(Appendix A) Abundance of calcareous dinoflagellates of sediment core GeoB2204-2@en

The environmental preferences of calcareous dinoflagellates have been investigated over the last 140 ka by comparing material from two sediment cores: one from the highly productive equatorial divergence of the eastern Atlantic Ocean and the other from the low productivity western tropical Atlantic Ocean. Pronounced differences in palaeoproductivity between the two sediment cores are indicated by high and variable organic carbon accumulation rates in the east, in contrast to relatively constant and low values in the west. Calcareous dinoflagellates show just the opposite pattern: high accumulation rates in the west and lower in the east. At the equatorial divergence, temporal variations of calcareous dinoflagellate and organic carbon accumulation rates show, for the most part, an inverse relationship. High calcareous dinoflagellate content coincides with low organic carbon accumulation rates and vice versa. In the investigated region and time interval, enhanced production of calcareous dinoflagellates can be correlated to periods of reduced palaeoproductivity probably related to relatively stratified conditions of the upper water column.本研究通过对比两根沉积物岩芯（sediment cores）的沉积物质，对过去140 ka以来钙质甲藻（calcareous dinoflagellates）的环境偏好展开了探究：其中一根岩芯采自东大西洋高生产力赤道辐散区，另一根采自西热带大西洋低生产力海域。两根岩芯的古生产力（palaeoproductivity）差异显著，东大西洋海域的有机碳堆积速率（organic carbon accumulation rates）较高且波动明显，而西大西洋海域的对应数值则相对稳定且偏低。钙质甲藻的堆积模式恰好相反：西大西洋海域的堆积速率更高，东大西洋海域则较低。在赤道辐散区，钙质甲藻与有机碳的堆积速率的时间变化整体上呈负相关关系，即高钙质甲藻含量对应低有机碳堆积速率，反之亦然。在本次研究的区域与时间区间内，钙质甲藻的产出增强可与古生产力降低的时期相关联，这大概率与上层水柱（upper water column）相对层化的环境条件有关。