Negative excursions in the stable carbon isotopic composition (δ¹³C) at Atlantic intermediate to mid‐depths are common features of millennial‐scale events named Heinrich Stadials. The mechanisms behind these excursions are not yet fully understood, but most hypotheses agree on the central role played by the weakening of the Atlantic meridional overturning circulation. Marine records registering millennial‐scale negative δ¹³C excursions in the Atlantic are mostly restricted to the Heinrich Stadials of the last deglacial, while the Heinrich Stadials of the last glacial are poorly studied. Here, we constrain changes in bottom water ventilation in the western tropical South Atlantic mid‐depth during Heinrich Stadials of the last glacial and deglacial by investigating marine core M125‐95‐3. The concurrent decreases in benthic foraminifera δ¹³C and increases in bulk sediment sulfur indicate an increased Northern Component Water (NCW) residence time in the western tropical South Atlantic mid‐depth during Heinrich Stadials. Furthermore, a coherent meridional pattern emerges from the comparison of our new data to previously published mid‐depth records from the western South Atlantic. While our record shows the largest negative δ¹³C excursions during almost all Heinrich Stadials, the western equatorialAtlantic showed medium and the subtropical South Atlantic showed the smallest negative excursions. This meridional pattern supports the notion that during Heinrich Stadials, a reduction in the NCW δ¹³C source signal together with the accumulation of respired carbon at NCW depths drove the negative δ¹³C excursions. We suggest that the negative δ¹³C excursions progressively increase along the NCW southwards pathway until the signal dissipates/dilutes by mixing with Southern Component Water.

中文翻译：

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约束热带南部南大西洋北部组件水通风的千禧年尺度变化

在稳定的碳同位素组成负偏移（δ ¹³ C）在大西洋中间到中等深度命名海因里希Stadials千年尺度的事件的共同特征。这些偏移的机制尚不完全清楚，但是大多数假设都同意大西洋经向翻转环流减弱的中心作用。海洋记录登记千年尺度的负δ ¹³大西洋的C游览大多仅限于最后一个冰期的海因里希球场，而对最后一个冰川的海因里希球场则研究较少。在这里，我们通过调查海洋核心M125‐95‐3，限制了最后一个冰川和冰河时期的海因里希（Heinrich）Stadials期间热带西部南大西洋中深度的底部水通风的变化。在底栖有孔虫δ并发下降¹³ ℃，散装硫磺沉淀增加表明海因里希Stadials在西部热带南大西洋深入中旬增加北方组件水（NCW）的停留时间。此外，通过将我们的新数据与先前发布的来自南大西洋西部的中深度记录进行比较，出现了一种连贯的子午线模式。虽然我们的记录显示最大的负δ在几乎所有的海因里希（Heinrich）球场中，¹³ C偏移，赤道西部的大西洋显示出中等程度的偏移，而亚热带南大西洋显示出最小的负偏移。此子午图案支持海因里希Stadials期间，在NCW减少δ概念¹³的C源信号连同呼出碳中的NCW深度积累开着负δ ^13个Ç游览。我们认为，负δ ^13个C ^游览逐渐与南方组件水混合沿着NCW向南途径增加，直到信号消散/稀释。