Glacial Radiocarbon Constraints from Drake Passage Deep-Sea Corals

该项目利用深海珊瑚中的放射性碳来了解南大洋在调节全球气候方面的作用。作为深水形成的关键地点，南大洋对深海和大气之间的热量和碳交换至关重要。它的变化可能与末次盛冰期的低大气二氧化碳有关，因为生物碳吸收增加或海气二氧化碳交换减少。由于缺乏适当的南大洋生物地球化学和环流记录，验证这些假设是具有挑战性的。深海珊瑚的文石骨架可能会提供一些见解，因为它们非常适合放射性碳分析——反映过去水柱的14C含量——同时也允许通过u系列年龄测量来确定事件的时间。总的来说，这些测量将对海气交换的范围、极地水柱分层以及来自南方的深水流向世界其他海洋的流量施加新的限制。作为这项工作的一部分，德雷克海峡海底的新部分将被绘制和成像，以及深海珊瑚和它们栖息地的现在和过去的分布。这项工作的一个重要的更广泛的影响是描述可能是对大气二氧化碳含量的关键控制的功能，这可能对充分了解持续二氧化碳排放的影响和制定缓解战略非常重要。此外，这项工作将描述人们对深海生态知之甚少，但越来越多地作为渔业资源开发的海洋生态。

This project uses radiocarbon in deep-sea corals to understand the Southern Ocean's role in modulating global climate. A key site of deep-water formation, the Southern Ocean is critical to exchange of heat and carbon between the deep-ocean and atmosphere. Changes in it may be linked to low atmospheric CO2 during the last glacial maximum through increased biologic carbon draw down or decreased air-sea CO2 exchange. Testing these hypotheses is challenging because of the scarcity of suitable records of the Southern Ocean's biogeochemistry and circulation. The aragonitic skeletons of deep-sea corals may offer insight because they are well suited for radiocarbon analyses-reflective of the 14C content of the past water column--while also allowing for timing of events through U-series age measurements. Overall, these measurements will put new constraints on the extent of air-sea gas exchange, polar water-column stratification, and the flux of Southern-sourced deep water to the rest of the world's oceans. As a part of this work, new sections of the Drake Passage sea floor will be mapped and imaged, along with the present and past distributions of deep-sea corals and their habitats. A significant broader impact of this work is characterizing the functioning of what may be a key control of atmospheric CO2 content, which could prove important for fully understanding the impacts of continued CO2 emissions and developing mitigation strategies. As well, the work will characterize deep marine ecologies that are poorly understood, but increasingly exploited as fisheries resources.