Millennial atmospheric CO2 changes linked to ocean ventilation modes over past 150,000 years
Millennial atmospheric CO2 changes linked to ocean ventilation modes over past 150,000 years
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DOI：
10.1038/s41561-023-01297-x
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发表时间：
2023-10
影响因子：
18.3
通讯作者：
J. Yu;R. F. Anderson;Z. Jin;X. Ji;D. Thornalley;L. Wu;N. Thouveny;Y. Cai;L. Tan
中科院分区：
文献类型：
--
作者：
J. Yu;R. F. Anderson;Z. Jin;X. Ji;D. Thornalley;L. Wu;N. Thouveny;Y. Cai;L. Tan
冰芯测量显示，在千年尺度的北大西洋寒冷时期，大气中的二氧化碳变化多样--增加、减少或保持稳定。这些截然不同的趋势的原因仍然难以捉摸。富含碳的深海的通风可以深刻地影响大气中的二氧化碳，但其千年尺度的历史受到的限制很小。在这里，我们展示了过去15万年来大西洋深处的高分辨率酸度记录，揭示了五种迄今未被检测到的静止海洋通风模式，它们对深海碳储存和相关的大气二氧化碳变化产生了不同的后果。我们的数据提供了观测证据，表明当大气CO2显著上升时，强烈的、往往是体积广泛的南大洋通风在主场期间释放了大量的深海碳。相比之下，其他场馆的特点是通过南大洋和北大西洋的通风较弱，这促进了呼吸性碳积累，从而减少或扭转了深海碳损失，导致大气中二氧化碳的上升幅度减小，甚至下降。我们的发现表明，深海碳储量和大气二氧化碳的千禧年尺度变化是由两个极地区域相互作用的多种海洋通风模式调制的，而不是仅受南大洋的调制，这对于全面理解过去和未来对气候变化的碳循环调整至关重要。
Ice core measurements show diverse atmospheric CO2variations—increasing, decreasing or remaining stable—during millennial-scale North Atlantic cold periods called stadials. The reasons for these contrasting trends remain elusive. Ventilation of carbon-rich deep oceans can profoundly affect atmospheric CO2, but its millennial-scale history is poorly constrained. Here we present a well-dated high-resolution deep Atlantic acidity record over the past 150,000 years, which reveals five hitherto undetected modes of stadial ocean ventilation with different consequences for deep-sea carbon storage and associated atmospheric CO2changes. Our data provide observational evidence to show that strong and often volumetrically extensive Southern Ocean ventilation released substantial amounts of deep-sea carbon during stadials when atmospheric CO2rose prominently. By contrast, other stadials were characterized by weak ventilation via both Southern Ocean and North Atlantic, which promoted respired carbon accumulation and thus curtailed or reversed deep-sea carbon losses, resulting in diminished rises or even declines in atmospheric CO2. Our findings demonstrate that millennial-scale changes in deep-sea carbon storage and atmospheric CO2are modulated by multiple ocean ventilation modes through the interplay of the two polar regions, rather than by the Southern Ocean alone, which is critical for comprehensive understanding of past and future carbon cycle adjustments to climate change.