Collaborative Research: Organic geochemical and isotopic reconstructions of North Pacific climate and sea ice variability

重建过去的海冰覆盖是古海洋学/古气候研究的一个基本挑战。关于突变的概念和数值模式以及高纬度和低纬度作为气候变化驱动因素的作用，将海冰作为变率的主要原因，但迄今为止还没有关于过去海冰范围的可靠代用物。了解海冰在过去变化中的作用也会严重影响我们对北极海冰覆盖未来变化后果的理解。本研究利用IP25海冰指数和TEX86温度指数这一新的有机生物标志物，重建了白令海和楚科奇海一系列高沉积速率岩心的海冰和相关海面温度变化。具体而言，研究人员将：(1)建立一个高纬度相对IP25浓度的空间数据集，并将这些化合物的分布与现代海冰范围进行比较；(2)建立一个新的高纬度海洋表面沉积物生物标志物分布数据库，并与已知的海温变化进行比较；(3)在选定的高纬度地点重建冰川晚期和全新世期间季节性海冰和相关海面温度的过去变化。除了更好地理解海冰范围在气候变化中的作用的社会意义之外，更广泛的影响包括支持一名博士生，本科生的夏季研究项目，以及德克萨斯大学奥斯汀分校的一名新教员。

Reconstructing past sea ice cover is a fundamental challenge in paleoceanography/paleoclimate research. Conceptual and numerical models of abrupt changes and the role of high vs. low latitudes as the drivers of climate change invoke sea ice as a principle cause of variability, but to date there have been no reliable proxies of past sea ice extent. Understanding the role of sea ice in past changes also critically impacts our understanding of the consequences of future changes in Arctic sea ice cover. This research calibrates and applies a set of new organic biomarkers (IP25 sea ice index, and TEX86 temperature index) to reconstruct changes in sea ice and associated sea surface temperatures from a series of high sedimentation rate cores from the Bering and Chukchi Seas. Specifically, the researchers will 1) produce a high latitude spatial dataset of relative IP25 concentrations and compare the distribution of these compounds with modern sea ice extent, 2) generate a new database of biomarker distributions in surface sediments from high-latitude oceans and compare with known SST variations, and 3) reconstruct past changes in seasonal sea ice and associated sea surface temperatures during the late glacial and Holocene from selected high latitude sites. In addition to the societal relevance of better understanding the role of sea ice extent in climate change, broader impacts include support of a PhD student, summer research projects for undergraduates, and a new faculty member at the University of Texas at Austin.