A New Approach to Reconstruct Ancient Bottom Water Oxygen Levels

Monday, 15 December 2014: 8:45 AM
Anthony Earl Rathburn1, Jake Willingham1, Bruce H Corliss2, Ashley M Burkett3 and Wiebke Ziebis4, (1)Indiana State University, Terre Haute, IN, United States, (2)University of Rhode Island Narragansett Bay, Narragansett, RI, United States, (3)Indiana State University, Earth and Environmental Systems, Terre Haute, IN, United States, (4)University of Southern California, Biological Sciences, Los Angeles, CA, United States
Oxygen availability controls many biological and geochemical processes, and serves as an important indicator of paleoceanographic characteristics. Recent work has demonstrated a direct relationship between oxygen acquisition and pores on benthic foraminiferal tests. Epifaunal foraminifera (living near or above the sediment-water interface) are directly exposed to bottom water, and can occur in abundance in a wide range of seafloor environments. In this study, a novel approach using ArcGIS and image analysis techniques was used to determine the percentage of test chamber surface area covered by pores in living and recently living (Rose Bengal stained) epifaunal taxa (Cibicides, Cibicidoides and Planulina). Analyses of Scanning Electron Microscope images of 97 specimens collected from 20 deep-sea locations having different bottom water oxygen concentrations (0.04 to 6.20 ml/L) revealed a robust (R2= 0.729; p < 0.001), negative relationship between pore surface area on test chambers and ambient bottom water oxygen concentration. The resulting calibration curve serves as new, quantitative proxy to assess bottom water oxygen of ancient oceans.