Late Quaternary Sea Ice History of the Beringian Arctic Gateway

北冰洋及其边缘海的海冰范围是冰-气-海耦合系统的重要组成部分，也是北冰洋海洋环流的驱动因素，但有关过去海冰状况的信息非常有限。这项拟议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制定季节性海冰范围和持续时间的定量措施。这将通过分析从白令海和楚科奇海收集的200多个表层沉积物中的硅藻形态、组合和冰相关硅藻的IP 25生物标志物来实现，这些沉积物跨越0-12个月/年的海冰。第二个目标是应用海冰重建使用校准硅藻组合方法和IP 25分析一套六个存档的核心，形成一个纬度样带通过白令海和楚科奇海。PI旨在以百年尺度分辨率定量重建晚更新世和全新世季节性海冰范围。这些努力将得到基于生物标志物的地表水温度独立评估的证实。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海冰和海面温度的历史。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受益于拟议的替代开发。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5至8年级学生介绍全球和北极气候，海洋沉积，生态系统适应不断变化的环境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.