Doctoral Dissertation Research: An Evaluation of Sedimentary Lipid Hydrogen Isotopes as an Arctic Precipitation Proxy

博士论文研究：沉积脂质氢同位素作为北极降水代理的评估

• 批准号: 1634118
• 负责人: Yarrow Axford
• 金额: $ 1.6万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1634118&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Evaluation; Sedimentary

This doctoral dissertation research project will characterize the distribution and hydrogen isotopic composition of plant biomarkers in lake sediments and modern plants to reconstruct past hydroclimate environments in the Arctic. By inferring the isotopic composition of past precipitation patterns and lake waters, this research will facilitate better modeling of the impacts of environmental change on Arctic ecosystems. Improved reconstruction of past hydroclimates will provide a more comprehensive understanding of the Arctic's atmospheric circulation responses to amplified thermal configurations. The project promises a significant STEM education component led by three early-career women that includes the engagement of several undergraduate students in research activities. In addition, the doctoral student will work with the PI on workshops for K-12 STEM teachers from Chicago and Evanston public schools to incorporate current scientific information into their educational materials. As a Doctoral Dissertation Research Improvement award, this award will provide support to enable a promising student to establish a strong independent research career.Existing paleoclimate records provide unique perspectives on how climate related to the hydrologic cycle varied temporally over the Arctic. However, there presently are insufficient data samples and inadequately calibrated proxies to confidently assess changes in hydroclimate. To facilitate improved reconstructions of past hydroclimate environments, the doctoral student will develop new methodologies for characterizing the distributions and hydrogen isotopic values of modern lipids in lake sediments and modern plants along an extensive latitudinal and climatic transect. Gas chromatography and mass spectrometry will be used on lake sediments cores to derive a dataset of plant biomarkers and their correlates (alkanes and acids.) Sedimentary leaf wax and aquatic plant lipid hydrogen isotopes will be measured and used to infer source water hydrogen isotopes by applying a fractionation correction. By answering fundamental questions about the characterization of lipid biomarkers and the relationship between lipid biomarkers and source water, the research will advance the broader application of using hydrogen lipid biomarkers as a paleohydrologic proxy in sedimentary archives.

该博士学位论文研究项目将表征湖泊沉积物和现代植物中植物生物标志物的分布和氢同位素组成，以重建北极中过去的氢气候环境。 通过推断过去降水模式和湖水的同位素组成，这项研究将有助于更好地建模环境变化对北极生态系统的影响。 改进的过去氢化物质的重建将对北极对放大热构型的大气循环反应提供更全面的了解。 该项目承诺由三名早期职业妇女领导的重要的STEM教育部分，其中包括几位本科生参与研究活动。 此外，博士生将与PI在芝加哥和埃文斯顿公立学校的K-12 STEM老师的研讨会上合作，将当前的科学信息纳入其教育材料中。 作为博士学位论文研究改进奖，该奖项将提供支持，使有前途的学生能够建立强大的独立研究职业。存在的古气候记录提供了关于气候与水文周期如何在北极相关的气候相关的独特观点。 但是，目前没有足够的数据样本和不充分的校准代理，无法确定评估氢化气候的变化。 为了促进改善过去氢气气候环境的重建，博士生将开发新方法，以表征沿湖泊沉积物和现代植物沿广泛的纬度和气候条带的现代脂质的分布和氢同位素值。 气相色谱和质谱法将用于湖泊沉积物核心，以得出植物生物标志物的数据集及其相关性（烷烃和酸。）沉积物叶蜡和水生植物脂质氢同位素将进行测量，并用于通过施加分数校正来测量并推断源水氢同位素。 通过回答有关脂质生物标志物的表征以及脂质生物标志物与源水之间的关系的基本问题，该研究将推动将氢脂质生物标志物用作沉积物档案中的古水合代理的更广泛应用。