Dinoflagellate cyst assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes, and geochemical parameters of sediment core GeoB9508-5

In order to investigate a possible connection between tropical northeast (NE) Atlantic primary productivity, Atlantic meridional overturning circulation (AMOC), and drought in the Sahel region during Heinrich Stadial 1 (HS1), we used dinoflagellate cyst (dinocyst) assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes (d13C) and geochemical parameters of a marine sediment core (GeoB 9508-5) from the continental slope offshore Senegal. Our results show a two-phase productivity pattern within HS1 that progressed from an interval of low marine productivity between ~ 19 and 16 kyr BP to a phase with an abrupt and large productivity increase from ~ 16 to 15 kyr BP. The second phase is characterized by distinct heavy planktonic d13C values and high concentrations of heterotrophic dinocysts in addition to a significant cooling signal based on reconstructions of past sea surface temperatures (SST). […]

为了探究热带东北大西洋初级生产力、北大西洋中纬度环流（AMOC）与希尼赫德斯塔阶1期（HS1）萨赫勒地区干旱之间的潜在联系，本研究采用了来自塞内加尔大陆架外缘的海洋沉积岩心（GeoB 9508-5）中的有孔虫类（dinocyst）组合、基于Mg/Ca的重建温度、稳定碳同位素（d13C）和地球化学参数。研究结果表明，在HS1期间存在两个阶段的初级生产力模式，从约19至16千年前BP的低海洋生产力阶段，过渡到约16至15千年前BP的突然且大幅度的生产力增加阶段。第二个阶段以独特的重浮游d13C值、异养有孔虫类的高浓度以及基于过去海表温度（SST）重建的显著冷却信号为特征。