Collaborative Research: Investigating Southern Ocean Sea Surface Temperatures and Freshening during the Late Pliocene and Pleistocene along the Antarctic Margin

Non-technical: As Antarctica’s ice sheets melt, freshwater enters the ocean, which can increase sea ice cover adjacent to the ice sheet. Sea ice formation changes the density of sea water thus regulating the circulation of water throughout the global ocean. Sea ice expansion may also slow down the processes driving ice sheet melt. This research will examine the relationship between surface ocean cooling and ocean freshening from geological records recovered adjacent, as well as farther seaward from the ice margin. These records will provide key information regarding the role in sea ice expansion during the process of deglaciation. The geological records span time intervals when climate conditions were similar to predicted future warming scenarios. Therefore, these new records will provide perspective on what the consequences of an ice sheet melting and surface ocean freshening might be in the near-term (100 years) and long-term (100-years) future. Broader impacts will include training for undergraduate researchers, dissemination of research findings through the Time Scavengers website and hands-on community science events, and engagement with school teachers and students. Technical Description: Ocean warming and Antarctic ice mass loss over the last few decades has resulted in surface freshening in the Ross Sea sector of the Southern Ocean. Surface ocean freshening is linked to sea ice expansion, which has an important role in regulating global ocean circulation and is hypothesized to be a negative climate feedback slowing ice retreat. The forcings and feedbacks involved in Southern Ocean warming, ice shelf melt, surface ocean freshening, sea ice growth, and deep water formation remain poorly understood due to the short-term nature of instrumental records. The objective of this research program is to: (1) generate multi-proxy Plio-Pleistocene sea surface temperature and meltwater records in ice-proximal and ice-marginal settings during deglacial and interglacial intervals from archived sediment cores of ANDRILL AND-1B as well as International Ocean Discovery Program (IODP) U1524, and (2) examine the external forcing mechanisms and orbital pacing of sea surface temperature and meltwater variability during the Plio-Pleistocene. Results from this project aim to better understand ocean-ice sheet driven dynamics under varying climate scenarios of the most recent geological past.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.

非技术性：随着南极洲的冰盖融化，淡水进入海洋，可以增加与冰盖相邻的海冰盖。海冰形成改变了海水的密度，从而减轻了整个全球海洋中水的循环。海冰扩展也可能会减慢驱动冰盖融化的过程。这项研究将研究地面海洋冷却与海洋新鲜的关系，从相邻回收的地质记录以及离冰缘遥远的地质记录之间的关系。这些记录将提供有关脱气过程中海冰扩展中作用的关键信息。当气候条件与预测的未来变暖方案相似时，地质记录涵盖时间间隔。因此，这些新记录将提供有关冰盖融化和表面海洋清新的后果可能会在近期（100年）和长期（100年）未来的后果。更广泛的影响将包括对本科研究人员的培训，通过《时间清道夫》网站和动手社区科学活动传播研究结果，以及与学校老师和学生的互动。技术描述：在过去的几十年中，海洋变暖和南极冰量损失导致南大洋的罗斯海域的表面新鲜。 Surface Ocean Fallsening与海冰扩张有关，海冰扩展在调节全球海洋循环中起着重要作用，并被认为是负面的气候反馈，从而减慢了冰的静修。由于工具记录的短期性质，涉及南大洋变暖，冰架融化，水冰生长和深水形成的强迫和反馈仍然很少了解。该研究计划的目的是：（1）在冰河和冰线冰期环境中产生多型冰川海面温度以及在冰冰和冰 - 边界环境中的融化记录。 Plio-Pleistecene期间的温度和融水变异性。该项目的结果旨在更好地了解海洋冰板驱动的动态在最新地质过去的不同气候场景下。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准来通过评估来诚实地支持支持。