报告摘要：

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 ocean acidity conditions using recently drilled sediments from IODP Expedition 397.

个人介绍：

于际民博士，崂山实验室研究员。在南京大学地球科学系获得本科（1999）和硕士学位（2002），在剑桥大学获得博士学位（2007）。先后在英国剑桥大学、美国哥伦比亚大学、美国劳伦斯弗莫尔国家实验室和澳大利亚国立大学地球科学学院（历任讲师、副教授、教授职位）从事科研和教学工作，2021年起就职于崂山实验室。于际民博士长期从事古海洋、古气候研究，开发和利用海洋生物碳酸盐微量元素和同位素替代指标（如, 有孔虫B/Ca），重建不同时间尺度（轨道、千年）海洋碳酸盐体系演化历史，并结合模拟手段探究相关调控机制及其对大气CO₂和气候的影响。近期工作侧重于IODP EXP397航次所获岩芯样品分析，以期提升我们对不同气候态条件下海洋碳循环调控机理的认识。