Deglacial to Recent Paleoceanography of the Sabrina Coast, East Antarctica: A Multi-proxy Study of Ice-ocean Interactions at the Outlet of the Aurora Subglacial Basin

南极洲西部的冰川退缩与海洋变暖有关；然而，人们对海洋对东南极冰川的影响知之甚少，其中包括位于萨布里纳海岸的托滕冰川。托滕冰川的消退具有全球意义，因为该冰川抽干了南极东部冰盖的一部分，那里的冰层足以使全球海平面上升3.5米。这项研究旨在通过研究南极周围的海底沉积物来确定过去18,000年来海洋温度对包括托滕冰川在内的南极东部冰川的影响。这些沉积物或泥浆包括微小海洋生物的遗骸，以及来自南极被侵蚀的基岩的微小颗粒。这些泥浆记录了过去的环境变化，包括海洋温度和冰川的进退。科学家们使用各种物理和化学分析来确定这种泥浆是在多长时间前沉积的，该地点的海洋温度随着时间的推移，以及冰川冰的相对位置。在这个项目中，研究人员将改进和测试从沉积物中测量海洋温度的新方法，以更好地了解海洋温度对南极东部冰川响应的影响。结果将被整合到冰盖和气候模型中，以提高冰盖建模工作和随后的海平面预测的准确性。该项目的成果将在科学会议、科学文献中传播，并通过圣彼得堡科学节和女孩海洋学夏令营更广泛地向广大公众传播。海洋温度对南极东部冰川的影响在很大程度上是未知的。这项研究的重点是冰-南极近缘古海洋学替代定标和验证，这将提高对过去各种时间尺度上的海洋-冰盖相互作用的理解。在这个项目中，南佛罗里达大学的研究人员将(1)进一步开发和提炼两个海温指标，即有孔虫镁/钙和TEX86，用于南极大陆边缘附近的冰层沉积物，以及(2)研究冰川退冰期，以显示气候敏感的极光冰下盆地出口处(~18-0ka)的海-冰相互作用。这项拟议的研究利用了之前在NSF资助的NBP14-02巡航期间从Sabrina海岸大陆架收集的沉积物陷阱、沉积物岩芯和物理海洋学数据。对现有沉积物岩心的研究将把多种古温度、融水/盐度、营养物质、底水氧气和海冰指标与地球物理和岩性数据结合起来，以了解过去的区域海冰相互作用。虽然最近国际南极研究的重点一直是了解西南极冰盖退缩的驱动因素，但模型表明，忽视东南极冰盖将是轻率的，因为事实证明，东南极冰盖对气候扰动比之前认识到的更敏感。这一奖项反映了NSF的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Glacial retreat in West Antarctica is correlated with ocean warming; however, less is known about the ocean's effect on East Antarctica's glaciers including Totten Glacier located on the Sabrina Coast. The retreat of Totten Glacier has global significance as the glacier drains a sector of the East Antarctic Ice Sheet that contains enough ice to raise global sea levels by as much as 3.5 meters. This study looks to determine the influence of ocean temperatures on East Antarctic glaciers, including Totten Glacier, over the last ~18,000 years by studying seafloor sediment around Antarctica. These sediments, or muds, include the remains of microscopic marine organisms as well as tiny particles originating from eroded Antarctic bedrock. These muds provide a record of past environmental changes including ocean temperatures and the advance and retreat of glaciers. Scientists use a variety of physical and chemical analyses to determine how long ago this mud was deposited, the temperature of the ocean at that location through time, and the relative location of glacial ice. In this project, researchers will refine and test new methods for measuring ocean temperature from the sediments to better understand the influence of ocean temperatures on East Antarctic glacier response. Results will be integrated into ice sheet and climate models to improve the accuracy of ice sheet modeling efforts and subsequent sea level predictions. Results from this project will be disseminated at scientific conferences, in the scientific literature, and more broadly to the general public via the St. Petersburg Science Festival and at the Oceanography Camp for Girls. The influence of ocean temperatures on East Antarctic glaciers is largely unknown. This research focuses on ice-proximal Antarctic margin paleoceanographic proxy calibration and validation, which will improve understanding of past ocean-ice sheet interactions on a variety of timescales. In this project, researchers from the University of South Florida will (1) further develop and refine two ocean temperature proxies, foraminifer Mg/Ca and TEX86, for use in ice-proximal Antarctic continental margin sediments and (2) investigate deglacial to present (~18-0 ka) ocean-ice interactions at the outlet of the climatically sensitive Aurora Subglacial Basin. The proposed research utilizes sediment trap, sediment core, and physical oceanographic data previously collected from the Sabrina Coast continental shelf during NSF-funded cruise NBP14-02. Studies of existing sediment cores will integrate multiple paleotemperature, meltwater/salinity, nutrient, bottom water oxygen, and sea ice proxies with geophysical and lithologic data to understand past regional ocean-ice interactions. While the recent international Antarctic research focus has been on understanding the drivers of West Antarctic Ice Sheet retreat, models suggest it would be imprudent to ignore the East Antarctic Ice Sheet, which is proving more sensitive to climate perturbations than previously realized.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.