The relative abundance (%) of planktonic foraminifera over time in core BAR 9403, located off the coast of Sumatra

The advent of deep-sea drilling in the 1950's prompted the use of planktonic foraminifera (unicellular protozans) as palaeoceanographic indicators. They provide a natural archive of past environmental changes due to their global distribution, their prolific productivity and sensitivity to environmental variations. The most obvious change in relative abundance in core BAR9403 (off the coast of Sumatra) is shown by sub-polar to transitional 'upwelling' species Ga. bulloides with abundances of 26% at approximately 14,000yrs BP and 22.7% during the Holocene. This is compared to the periods from Marine Isotope Stage (MIS) 3 to the Last Glacial Maximum (LGM) where the relative abundance of Ga. bulloides is generally

20世纪50年代深海钻探技术的问世，推动了浮游有孔虫（planktonic foraminifera，单细胞原生动物）作为古海洋学指标（palaeoceanographic indicators）的应用。这类生物凭借全球分布、繁殖力旺盛且对环境变化敏感的特性，成为记录过去环境变化的天然档案。在苏门答腊近海的BAR9403岩心中，亚极地至过渡型“上升流”类群布氏球房虫（Ga. bulloides）的相对丰度变化最为显著：其在约14000年前（BP）的丰度达26%，全新世时期丰度为22.7%。该结果与海洋同位素阶段（Marine Isotope Stage，MIS）3至末次冰盛期（Last Glacial Maximum，LGM）时期的情况形成对照，此阶段布氏球房虫的相对丰度整体