Late Quaternary Sea Ice History of the Beringian Arctic Gateway

北冰洋及其边缘海域的海冰范围是冰-大气-海洋耦合系统的关键组成部分，也是海洋经向环流的驱动因素，但过去关于海冰状况的信息非常有限。这项研究的目标是双重的。第一个是利用从白令海和楚科奇海收集的存档表层沉积物来开发季节性海冰范围和持续时间的定量测量。这将通过分析从白令海和楚科奇海收集的200多个表面沉积物中收集的硅藻形态、组合和冰相关硅藻的IP25生物标志物来实现，这些沉积物跨越0-12个月/年的海冰。第二个目标是利用校准的硅藻组合方法和IP25分析对一套六个存档岩芯进行海冰重建，这些岩芯形成了贯穿白令海和楚科奇海的纬度样带。PIs旨在以百年尺度定量重建晚更新世和全新世的季节海冰范围。这些努力将被独立的基于生物标志物的地表水温度评估所证实。该项目的成功完成将产生丰富的多代理数据集，用于评估白令海峡地区的海冰和海面温度历史。该项目的结果将与全球气候建模者以及对区域到全球尺度强迫问题感兴趣的古生态学家、古气候学家和古海洋学家有关。更广泛的北极科学界将从拟议的代理开发中受益。该项目每年将资助两名全日制研究生和一名暑期本科生研究助理。pi和学生还将继续开发课程模块，旨在向五年级到八年级的学生介绍全球和北极气候、海洋沉积、生态系统对变化环境的适应以及生物分类等主题。

Sea ice extent in the Arctic Ocean and its marginal seas is a key component of the coupled ice-atmosphere-ocean system and a driver of meridional ocean circulation, yet information about sea ice conditions in the past is very limited. The goals of this proposed study are two-fold. The first is to use archived surface sediments collected from the Bering and Chukchi Seas to develop quantitative measures of seasonal sea-ice extent and duration. This will be achieved through analysis of diatom morphology, assemblages and the IP25 biomarker of ice-associated diatoms from a suite of over 200 surface sediments collected from the Bering and Chukchi Seas spanning 0-12 months/year of sea ice. The second goal is to apply sea ice reconstructions using the calibrated diatom assemblage methods and IP25 analysis to a suite of six archived cores that form a latitudinal transect through the Bering and Chukchi Seas. The PIs aim to quantitatively reconstruct Late Pleistocene and Holocene seasonal sea ice extent at centennial-scale resolution. These efforts will be corroborated with independent biomarker-based evaluation of surface water temperatures. The successful completion of the project will result in a rich, multi-proxy data set that will be used to evaluate the sea ice and sea surface temperature history of the Bering Strait region. The results of this project will be relevant to global climate modelers as well as paleoecologists, paleoclimatologists, and paleoceanographers interested in regional- to global-scale forcing issues. The broader Arctic science community would benefit from the proxy development proposed. The project would support two full-time graduate students and a summer undergraduate research assistant in each year of the project. The PIs and students will also continue to develop curriculum modules designed to introduce 5th through 8th grade students to the topics of global and Arctic climate, marine sedimentation, ecosystem adaptation to changing environments, and the classification of organisms.