Atmospheric carbon dioxide and ocean circulation changes during the middle Miocene climate transition

中新世中期气候转变期间大气二氧化碳和海洋环流的变化

• 批准号: 421821560
• 负责人: Dr. Markus Raitzsch
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/421821560?language=en
• 关键词: Atmospheric; carbon; dioxide; ocean; circulation

In a recent study based on boron isotopes in planktic foraminifera, we found that after the mid-Miocene Antarctic glaciation atmospheric pCO2 rose rapidly before returning to pre-glaciation values, which is surprising since it is opposite to what was widely assumed in the literature. We conclude that this transient rise in pCO2 is supposedly caused by enhanced meridional deep-ocean circulation. We need, however, to verify our hypothesis by investigating Miocene sediment cores from different areas and different depths to (1) eventually observe changes in ocean circulation from benthic records, and (2) to consolidate pCO2 records from the planktic records. The middle Miocene is still a hot topic among paleoclimatologists, and may provide insights into the tight coupling between Antarctic ice and the global carbon cycling. This time interval is especially interesting, because atmospheric pCO2 appears to have been similar to today and we are going to face the reversal of the middle Miocene climate transition, i.e. a substantial reduction in Antarctic ice volume. Hence the knowledge of processes involved in the interaction between mid-Miocene ice volume and global carbon cycle may be important for future predictions of our warming planet.

在最近的一项基于南极有孔虫中硼同位素的研究中，我们发现，在中新世中期南极冰川作用之后，大气pCO2在恢复到冰川作用前的值之前迅速上升，这是令人惊讶的，因为它与文献中广泛假设的相反。我们的结论是，这种pCO2的瞬时上升，据推测是由增强的纬向深海环流。然而，我们需要通过调查来自不同地区和不同深度的中新世沉积物岩心来验证我们的假设，以（1）最终从底栖记录中观察海洋环流的变化，以及（2）从南极记录中整合pCO2记录。中新世中期仍然是古气候学家的一个热门话题，并可能为南极冰与全球碳循环之间的紧密耦合提供见解。这个时间间隔特别有趣，因为大气pCO2似乎与今天相似，我们将面临中中新世气候转变的逆转，即南极冰量大幅减少。因此，了解中中新世冰量与全球碳循环之间相互作用的过程对于未来预测我们的地球变暖可能很重要。