During the last deglaciation (~18–11 thousand years ago), existing radiocarbon (¹⁴C) reconstructions of intermediate waters in the mid- to low-latitude oceans show widely diverging trends, with some broadly tracking the atmosphere and others suggesting extreme depletions. These discrepancies cloud our understanding of the deglacial carbon cycle because of the diversity of hypotheses needed to explain these diverging records, for example, injections of ¹⁴C-dead geological carbon, mixing of extremely isolated waters from the abyssal ocean or changes in sites of deep-water ventilation. Here we present absolutely dated deglacial deep-sea coral ¹⁴C records of intermediate waters from the Galápagos Platform—close to the largest reported deglacial ¹⁴C depletions—together with data from the low-latitude Atlantic. Our records indicate coherent, well-equilibrated intermediate-water ¹⁴C ventilation in both oceans relative to the atmosphere throughout the deglaciation. The observed overall trend towards ¹⁴C-enriched signatures in our records is largely due to enhanced air–sea carbon isotope exchange efficiency under increasing atmospheric \({p_{{\rm {CO}}_2}}\). These results suggest that the ¹⁴C-depleted signatures from foraminifera are likely sedimentary rather than water mass features, and provide tight ¹⁴C constraints for modelling changes in circulation and carbon cycle during the last deglaciation.

在最后一次冰消期（约18至11000年前）中，中低纬度海洋中层水的现有放射性碳（¹⁴ C）重建显示出广泛的趋向，其中一些广泛追踪大气，而另一些则表明极度耗竭。这些差异模糊了我们对冰期碳循环的理解，因为需要解释这些不同记录的假设的多样性，例如，注入¹⁴ C死的地质碳，混合来自深海的极度孤立的水或深处的变化-水通风。在这里，我们展示了来自加拉帕戈斯站的中间水域的绝对年代的冰河深海珊瑚¹⁴ C记录-接近最大的冰河^14记录。C损耗-以及来自低纬度大西洋的数据。我们的记录表明，整个冰消期间，两个海洋相对于大气的连贯，平衡良好的中间水¹⁴ C通风。在我们的记录中观察到的向¹⁴个富含C的特征签名的总体趋势主要是由于在大气\（{p _ {{\ rm {CO}} _ 2}} \\）不断增加的情况下提高了海-海碳同位素交换效率。这些结果表明，有孔虫的¹⁴ C贫乏特征可能是沉积特征，而不是水团特征，并为模拟最后一次冰消期间的循环和碳循环变化提供了严格的¹⁴ C约束。