Deglacial Transport through the Florida Straits: Constraints on Atlantic Ocean Circulation during the Younger Dryas, Heinrich Event 1 and the Last Glacial Maximum

在这个项目中，我们将调查在地球从最后一个冰河时代出现时发生的突然气候变化期间大西洋环流是如何变化的。我们的数据将有助于验证新仙女木时期的寒冷期是由大西洋经向翻转环流强度的减弱引起的，而海因里希事件期间大量淡水流入北大西洋，完全阻止了这种翻转。我们将利用氧同位素、Mg/Ca和底栖生物和深海浮游有孔虫的测量重建佛罗里达海峡水域的密度结构。利用一种新颖的地转建模方法，将这些信息结合起来，创建1万至2万年前佛罗里达海峡千年尺度的运输历史，包括新仙女木期/博林阿勒罗德气候振荡、海因里希事件1和末次盛冰期。经向翻转环流的上端沿西边界向北大西洋移动时经过佛罗里达海峡，翻转强度的任何实质性减弱都会反映在通过该海峡的气流减少上。了解大西洋经向翻转环流过去的稳定性及其与气候突变的关系，在我们试图了解未来几个世纪气候的轨迹时，对社会具有极大的兴趣。本科生和研究生在合作这个项目时将接受培训。PI将通过与媒体和当地教育组织的联系，将这项研究传达给佐治亚理工学院的新一代学生，并传达给更广泛的社区。

In this project, we will investigate how Atlantic Ocean circulation changed during the abrupt climate changes that occurred as the earth emerged from the last Ice Age. Our data will help to test the hypotheses that the Younger Dryas cold period was caused by a decrease in the strength of the Atlantic meridional overturning circulation and that the large discharges of freshwater into the North Atlantic during Heinrich Events shut down this overturning altogether. We will reconstruct the density structure of waters in the Florida Straits using oxygen isotope and Mg/Ca and measurements on benthic and deep dwelling planktonic foraminifera. This information will be combined to create a millennial scale transport history for the Florida Straits between 10,000 and 20,000 years ago, including the Younger Dryas/Bolling Allerod climate oscillation, Heinrich Event 1 and the last glacial maximum, using a novel geostrophic modeling method. The upper limb of the meridional overturning circulation passes through the Florida Straits as it travels along the western boundary towards the North Atlantic and any substantial reductions in the strength of the overturning will be reflected in a reduction of the flow through the straits. Understanding the past stability of the Atlantic meridional overturning circulation and its relationship to abrupt climate change is of great interest to society as we seek to understand the trajectory of climate over the next centuries. Undergraduate and graduate students will be trained as they collaborate on this project. The PI will communicate this research to a new generation of students at Georgia Tech and to the broader community through contacts with the media and local educational organizations.