Collaborative Research: Calibration of a new approach to reconstruct ancient bottom water oxygen levels

溶解氧有效性的变化强烈地影响着海洋系统中的生物和地球化学过程。然而，海洋氧浓度往往与其他环境因素共同变化，如有机碳通量，混淆了大多数深海环境中溶解氧浓度的古海洋学替代指标。这项合作项目涉及印第安纳州立大学和杜克大学的研究人员和学生，旨在根据底栖有孔虫的贝壳形态开发一种海底氧气水平的替代物。这项研究将包括一次在加利福尼亚州圣地亚哥附近的海上探险，以收集样本。研究人员将使用扫描电子显微镜(SEM)和图像分析工具对存档和新收集的样本进行定量分析，以校准深海表层生物类群的溶解氧和孔隙密度之间的关系。具体地说，它们将决定：1)孔密度对氧合作用的微小变化有多敏感，2)孔特征在明显的分类边界内和跨明显的分类边界如何变化，以及3)最适合每个物种的溶解氧范围。资金支持这两个机构的学生，包括他们参加邮轮。研究团队还将开发一个邮轮博客，并将在印第安纳州立大学的互动展览中展示。

Changes in dissolved oxygen availability strongly influence biological and geochemical processes in marine systems. However, marine oxygen concentrations often co-vary with other environmental factors, such as organic carbon flux, confounding paleoceanographic proxies for dissolved oxygen concentration in most deep-sea settings. This collaborative project, involving researchers and students from Indiana State University and Duke University, seeks to develop a proxy for bottom-water oxygen levels based on the shell morphology of benthic foraminifera. The research will include a sea-going expedition off San Diego, CA, to collect samples. The researchers will use Scanning Electron Microscopy (SEM) and image analysis tools for quantitative analysis of both archived and newly collected samples to calibrate the relationship between dissolved oxygen and pore densities of living epifaunal deep sea taxa. Specifically, they will determine: 1) how sensitive pore density is to small changes in oxygenation, 2) how pore characteristics change within and across obvious taxonomic boundaries, and 3) the range of dissolved oxygen that is best for each species. Funding supports students at both institutions, including their participation on the cruise. The research team will also develop a cruise blog that will be featured in an interactive exhibit at Indiana State University.