Globigerinoides ruber, Globigerina bulloides and MAT derived paleotemperatures for the lasts 772 kyr from cores GL-852 and GL-854 (Santos Basin, Southwest Atlantic)@en

Expansions of coastal upwelling spots along the Brazilian coast were previously reported for Marine Isotope Stage (MIS) 5, but open questions remain regarding the climatic mechanisms and the periodicity of such changes. Based on two marine sediment cores, we provide evidence for multiple intensifications of the upwelling regime off the Southeast Brazilian margin (SBM) during several interglacials and highlight the major role of eccentricity as the responsible forcing. In addition, we show a two-step change in the upwelling regime across the Mid-Brunhes Event (MBE) and an increase in the amplitude of upwelling variability after this climatic transition. Our findings point to substantial modifications of the upwelling regions during several glacial-interglacial transitions that probably altered the regional marine productivity regime and the carbon budget.此前已有研究报道，巴西沿岸的沿岸上升流区在海洋同位素阶段（Marine Isotope Stage，MIS）5期间发生扩张，但这类变化的气候驱动机制与周期仍存在诸多未解科学问题。本研究基于两根海洋沉积物岩芯，为巴西东南陆缘（Southeast Brazilian margin，SBM）海域的上升流系统在多场间冰期内的多期增强提供了实证依据，并强调轨道偏心率作为该系统变化的核心驱动因子的关键作用。此外，本研究揭示了巴西东南陆缘上升流系统在中布容事件（Mid-Brunhes Event，MBE）期间发生的两步式变化，并发现该气候转型后，上升流变率的振幅显著增大。本研究结果表明，多场冰期-间冰期旋回期间，上升流区发生了显著改造，这可能改变了区域海洋生产力系统与碳收支平衡。