Changes in ocean ventilation, controlled by both overturning rates and air‐sea gas exchange, are thought to have played a central role in atmospheric CO₂ rise across the last deglaciation. Here, we constrain the nature of Atlantic Ocean ventilation changes over the last deglaciation using radiocarbon and stable carbon isotopes from two depth transects in the Atlantic basin. Our findings broadly cohere with the established pattern of deglacial Atlantic overturning change, and underline the existence of active northern sourced deep‐water export at the Last Glacial Maximum (LGM). We find that the western Atlantic was less affected by incursions of southern‐sourced deep water, as compared to the eastern Atlantic, despite both sides of the basin being strongly influenced by the air‐sea equilibration of both northern and southern deep‐water end‐members. Ventilation at least as strong as modern is observed throughout the Atlantic during the Bølling‐Allerød (BA), implying a “flushing” of the entire Atlantic water column that we attribute to the combined effects of Atlantic meridional overturning circulation (AMOC) reinvigoration and increased air‐sea equilibration of southern sourced deep‐water. This ventilation “overshoot” may have counteracted a natural atmospheric CO₂ decline during interstadial conditions, helping to make the BA a “point of no return” in the deglacial process. While the collected data emphasize a predominantly indirect AMOC contribution to deglacial atmospheric CO₂ rise, via far field impacts on convection in the Southern Ocean and/or North Pacific during Heinrich Stadial 1 and the Younger Dryas, the potential role of the AMOC in centennial CO₂ pulses emerges as an important target for future work.

中文翻译：

---

大西洋末次冰期的通风变化及其碳循环意义

人们认为，由倾覆速率和海气交换所控制的海洋通风变化在大气CO _2中起着核心作用在最后一次冰消过程中上升。在这里，我们使用大西洋盆地两个深度样带中的放射性碳和稳定碳同位素，限制了最后一次冰消期间大西洋通风变化的性质。我们的发现在很大程度上与已建立的冰河大西洋俯覆变化模式相吻合，并强调了在最后一次冰河最高期（LGM）北部活跃的深水出口活动的存在。我们发现，与盆地东部相比，西部大西洋受南部源深水入侵的影响较小，尽管盆地两侧都受到北部和南部深水末端的海海平衡的强烈影响。成员。在整个Bølling-Allerød（BA）期间，整个大西洋的通风情况至少与现代通风一样强，这意味着整个大西洋水柱的“冲洗”是我们归因于大西洋经向翻转环流（AMOC）复活和南部源深水的海海平衡增加的综合作用。这种通风“超调”可能抵消了自然大气中的CO₂在星际条件下下降，有助于使BA成为冰消融过程中的“不归路”。尽管收集到的数据强调了AMOC对冰期大气CO ₂升高的主要间接贡献，但在Heinrich Stadial 1和Younger Dryas期间，远场影响了南洋和/或北太平洋的对流，AMOC在百年一遇的CO中的潜在作用₂脉冲成为未来工作的重要目标。