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，以重建北极过去的水文气候环境。 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模拟环境变化对北极生态系统的影响。 改进过去水文气候的重建将使人们更全面地了解北极大气环流对放大的热配置的响应。 该项目承诺由三名早期职业女性领导重要的 STEM 教育内容，其中包括让几名本科生参与研究活动。 此外，博士生还将与 PI 合作，为芝加哥和埃文斯顿公立学校的 K-12 STEM 教师举办研讨会，将当前的科学信息纳入他们的教育材料中。 作为博士论文研究改进奖，该奖项将为有前途的学生建立强大的独立研究生涯提供支持。现有的古气候记录为与水文循环相关的气候如何在北极随时间变化提供了独特的视角。 然而，目前没有足够的数据样本和不充分校准的代理来自信地评估水文气候的变化。 为了促进改善过去水文气候环境的重建，博士生将开发新的方法来表征沿广泛纬度和气候横断面的湖泊沉积物和现代植物中现代脂质的分布和氢同位素值。 气相色谱法和质谱法将用于湖泊沉积物岩心，以获得植物生物标志物及其相关物（烷烃和酸）的数据集。将测量沉积叶蜡和水生植物脂质氢同位素，并通过应用来推断源水氢同位素分馏校正。 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关系的基本问题，该研究将推动使用氢脂质生物标志物作为沉积档案中的古水文代理的更广泛应用。