Processes underlying changes in the oceanic carbon storage during the Last Glacial Maximum and the subsequent deglaciation are not fully understood. Here, we present a new high‐resolution radiocarbon reconstruction (expressed as δ¹⁴R) at the depth of the modern Lower Circumpolar Deep Water from the Pacific Sector of the Southern Ocean. Our record shows δ¹⁴R increases during Heinrich Stadial 1 and the Younger Dryas that agree with the deep‐to‐shallow transfer of old carbon in the Southern Ocean during these two periods. Our record also shows, for the first time, a clear ∼80‰ decline in δ¹⁴R during the Antarctic Cold Reversal (ACR), indicating the development of poorly ventilated conditions in the deep Southwest Pacific. These conditions are consistent with the increased Southern Ocean sea‐ice and associated stratification between Upper and Lower Circumpolar Deep Waters. This enhanced stratification in the deep South Pacific possibly facilitated greater carbon storage in the ocean interior during the ACR, effectively limiting oceanic CO₂ release and contributing to the atmospheric CO₂ plateau as observed in ice cores at that time.

中文翻译：

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西南太平洋深部的冰河通气变化

尚未完全了解“最后一次冰期最大值”期间海洋碳储量变化的潜在过程以及随后的冰消过程。在这里，我们提出了一个新的高清晰度放射性碳重建（表示为δ ¹⁴在现代下绕极深层水从南大洋的太平洋扇区深度R）。我们的记录显示δ ^14个海因里希于冰阶1时和R增加新仙女木，与在这两个时期南大洋深到浅转移旧碳的认同。我们的记录还显示，首次，明确〜80‰下降δ ¹⁴南极逆冷（ACR）期间的R，表示西南太平洋深部通风不良条件的发展。这些条件与南极海洋海冰的增加以及上下极地深水区之间的分层有关。在ACR期间，南太平洋深层的这种增强的分层可能促进了海洋内部更多的碳储存，有效地限制了海洋CO _2的释放，并有助于当时在冰芯中观测到的大气CO ₂平稳期。