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

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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.