海洋科学学术讲座预告第369期：Bipolar control on millennial atmospheric CO2 changes over the past glacial cycle 末次冰期旋回过程中大气二氧化碳千年尺度变化的双极控制

报告内容简介：

        Ice-core measurements show diverse atmospheric CO2 variations – increasing, decreasing or remaining stable – during millennial-scale North Atlantic cold periods called stadials. The reasons for these contrasting trends remain elusive, because they are difficult to be explained by Southern Ocean processes alone. Ventilation of carbon-rich deep oceans can profoundly affect atmospheric CO2, but its millennial-scale history is poorly constrained. In this talk, I will show a high-resolution deep-water acidity record from the Iberian Margin in the North Atlantic, a unique setting that allows us to construct a robust chronology for confident comparisons between marine and ice-core records. The new data combined with ice-core CO2 records reveal multiple ocean ventilation modes involving an interplay of the two polar regions, rather than by the Southern Ocean alone. These modes governed past deep-sea carbon storage and atmospheric CO2 variations on millennial timescales. I will also share some progress in my group, including new approaches (e.g., foraminiferal boron isotopes for surface-water pCO2 reconstructions) to investigate polar ocean carbon cycle and ongoing research to reconstruct long-term acidity conditions using recently drilled sediments from IODP Expedition 397.

        冰芯测量显示，在千年尺度上的北大西洋冷期，大气中二氧化碳呈现出变化的多样性。这些变化的原因难以仅用南大洋过程解释。深海通风过程可以深刻影响大气中的二氧化碳，但其在千年尺度上的变化却难以约束。在本次演讲中，我将展示北大西洋伊比利亚边缘的高分辨率深水酸度记录，这个独特海域的记录使我们能够构建可靠的年代框架，以便对海洋和冰芯记录进行更好的比较。结合冰芯记录，我们的新数据揭示了两极过程对复杂的深海通风模式的控制。这些模式主导了以往的深海储碳和大气中二氧化碳的变化。此外，报告也将介绍本团队在极地碳循环研究方面的进展和基于IODP 397航次获取的新样品开展的更长时间尺度上的海洋酸化研究。