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

溶解氧可用性的变化强烈影响海洋系统中的生物和地球化学过程。然而，海洋氧浓度经常与其他环境因子（如有机碳通量）共同变化，混淆了大多数深海环境中溶解氧浓度的古海洋学代用指标。这个合作项目包括来自印第安纳州立大学和杜克大学的研究人员和学生，他们试图根据底栖有孔虫的外壳形态来开发一种底水含氧量的替代品。这项研究将包括在加州圣地亚哥附近进行一次海上考察，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品进行定量分析，以校准活的深海分类群的溶解氧与孔隙密度之间的关系。具体来说，他们将确定：1)孔隙密度对氧合的微小变化有多敏感；2)孔隙特征在明显的分类边界内和边界之间是如何变化的；3)对每个物种最有利的溶解氧范围。资金支持两所学校的学生，包括他们参加游轮活动。该研究小组还将开发一个邮轮博客，并将在印第安纳州立大学的一个互动展览中展出。

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.