Stable isotope record of Cibicidoides wuellerstorfi from Pleistocene sediments of DSDP Site 86-502 in the Caribbean Sea

Variations in the stable isotopic composition of benthic foraminifera from Deep-Sea Drilling Project (DSDP) site 502B in the Caribbean Sea are used to reconstruct Atlantic intermediate water circulation variability over the last 1.2 m.y. Comparison of this record with other North Atlantic benthic isotope records indicates that Atlantic intermediate water circulation was relatively enhanced during glacial maxima when North Atlantic deep water (NADW) production was reduced. However, a simple, compensatory relationship between intermediate and deepwater circulation is not apparent. Geochemical models have shown that such changes in ocean circulation can affect atmospheric CO2 levels by changing vertical nutrient and alkalinity profiles. The Delta delta13C difference between Caribbean site 502B and deep equatorial Pacific site 677 is highly coherent and in phase with ice volume. […]

本研究所涉及的加勒比海深海钻探计划（DSDP）502B站位底栖有孔虫稳定同位素组成的变异性，被用于重建过去1.2百万年内大西洋次表层水流的变化。将该记录与北太平洋其他次表层同位素记录进行比较表明，在冰期盛期，随着北大西洋深层水（NADW）产量的减少，大西洋次表层水流相对增强。然而，次表层与深层水流之间的简单补偿关系并不明显。地球化学模型表明，此类海洋环流的变化可以通过改变垂直营养盐和碱度分布来影响大气CO2水平。加勒比海502B站位与深海赤道太平洋677站位的δδ13C差值与冰体积变化高度一致，且相位同步。