Cross-validation of xsBa and Benthic Foraminiferal Assemblages as proxies of organic matter flux in the Equatorial Pacific

Foraminiferal assemblage compositions are commonly used as proxies for productivity in paleoceanographic records. Previous research on modern benthic foraminifer assemblages shows that abundances of opportunistic taxa increase with increases in phytodetritus flux. Barium is also used as a proxy for primary productivity in surface waters and increases ²³⁰Th-derived xsBa fluxes are interpreted as increases in organic matter fluxes. This study examines the relationship between the opportunistic benthic foraminifer species Alabaminella weddellensis and increases in barium concentrations to cross-validate these metrics as a proxies for organic matter flux to the seafloor. This taxon is especially useful as it is common in deep sea sediments with broad water depth distributions. Preliminary data suggests that changes in the proportional abundance of A. weddellensis in the benthic population over the last 25,000 years from the Eastern Equatorial Pacific (NOAA site MV1014-02-17JC) are positively associated with barium concentrations, such that high proportional abundances of A. weddellensis occur when barium concentrations are high. The results of this study suggest that the proportional abundance of this phytodetrital taxon and xsBa concentrations are each reasonable proxies for high fluxes of organic matter derived from increased primary productivity in the surface waters of the Eastern Equatorial Pacific.