Deciphering the Subantarctic South Pacific Ocean’s Role in Pleistocene Climate Evolution with IODP Expedition 383 Sediments

南大洋是全球气候系统的一个关键因素。它是南极绕极流的发源地，这是地球上最快的洋流。作为一个强大的碳汇，它代表了抵御人类造成的温室气体排放的一些影响的重要屏障。然而，驱动南大洋变化的过程仍然鲜为人知。该项目将调查过去200万年南太平洋在气候系统中的作用。它将使用最近在乔迪斯决议号钻探探险中回收的沉积物岩心来完成这项工作。该项目将生成海洋表面状况的记录，可以让我们了解海洋吸收二氧化碳并将其储存在深海中的能力。地球科学是STEM领域中代表性不足的少数族裔参与最少的领域。该项目将采用队列学生计划，以积极促进多样性和扩大参与。在一位心理学教授的指导下，该项目将通过多样性创造一个促进参与、学习和创新的环境。这种队列方法的目标是将地球科学教育从一种基于把关的方式转变为一种邀请和支持来自不同背景的人的方式。气候科学界对地球长期气候演变的认识主要来自北半球的气候记录。考虑到南大洋在全球气候系统中的核心作用及其与南极冰盖的接近性，南半球的数据缺口严重阻碍了我们了解重大气候转变期间海洋-大气-冰盖动力学和碳循环的全球变化的能力。来自南太平洋的记录对于提高我们对这些过程的理解尤其有价值，因为到目前为止，太平洋包含了南大洋最大的表面积和体积分数，因此在深海中拥有最大的碳储存能力。本项目拟利用383考察期间获得的新沉积物岩心，生成过去200万年的高分辨率气候代理时间序列，重点是中更新世过渡时期（MPT）。这些长期记录将通过重建沙尘输入、养分利用和输出生产来探索海洋表面气候/碳动态的变化，并将这些记录与合作者的海面温度、水团结构和环流记录进行综合和解释。利用美国三家机构的专业知识，该项目将在亚南极太平洋的三个钻探点（U1539、U1540和U1541）生产一套前所未有的互补生物和地球化学示踪剂。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Southern Ocean is a key element of the global climate system. It is home to the Antarctic Circumpolar Current, the fastest ocean current on Earth. As a strong carbon sink, it represents an important shield against some of the effects of human-caused greenhouse gas emissions. However, the processes driving the Southern Ocean’s variability are still poorly known. This project will investigate the role of the South Pacific in the climate system over the past 2 million years. It will do so using sediment cores recovered during a recent drilling expedition on the Joides Resolution. The project will generate records of surface ocean conditions that can inform our understanding of the capacity of the ocean to take up carbon dioxide and store it in the deep ocean. The geosciences are the STEM field with the least participation from underrepresented minorities. The project will use a cohort student program to actively promote diversity and broadened participation. Under the guidance of a psychology professor, the project will create an environment that enhances engagement, learning and innovation through diversity. A goal of this cohort approach is to shift geoscience education from a style based on gatekeeping to one that that is inviting and supportive of people from diverse backgrounds.The climate science community’s understanding of Earth’s long-term climate evolution predominantly comes from Northern Hemisphere climate records. Given the central role of the Southern Ocean in the global climate system and its proximity to the Antarctic Ice Sheet, the Southern Hemisphere data gap severely inhibits our ability to understand global changes in ocean-atmosphere-ice sheet dynamics and carbon cycling during major climatic transitions. Records from the South Pacific are especially valuable to improve our understanding of these processes, because the Pacific contains by far the largest surface area and volume fraction of the Southern Ocean and therefore holds the largest capacity for carbon storage in the deep ocean. This project proposes to generate high-resolution climate proxy time series over the past 2 million years with emphasis across the Mid-Pleistocene Transition (MPT) using new sediment cores recovered during Expedition 383. These long records will explore changes in climate/carbon dynamics at the ocean surface by reconstructing dust input, nutrient utilization, and export production and these records will be synthesized and interpreted with collaborators’ records of sea surface temperature, water mass structure and circulation. Drawing from expertise across three US institutions, the project will produce an unprecedented suite of complementary biological and geochemical tracers at three drill sites (U1539, U1540, and U1541) in the Subantarctic Pacific.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.