Francois¹, Roger, Susumu Honjo¹, Steve Manganini¹, Robert Collier², Jack Dymond² and Ahmed Rushdi²

¹Woods Hole Oceanographic Institution, Woods Hole, MA 02543, Tel: 508-289-2637, E-mail: rfrancois@whoi.edu and ²Oregon State University, Corvallis, OR 97331-5503

What controls the flux of Ba to the deep-sea?

It has long been recognized that the Ba flux reaching the seafloor is generally higher in productive regions and this has lead to the use of Ba burial in sediment as a means of reconstructing past changes in the overlying biological productivity. During the JGOFS program, sediment trap deployments have resulted in an extensive ocean-wide database on deep-sea elemental fluxes. In addition, we have recently gained new insights into the mechanism of barite formation and into the role of biogenic minerals in controlling the flux of organic carbon to the deep-sea. This and the availability of synoptic productivity maps based on satellite data provide a new opportunity to revisit the Ba-based paleoproductivity algorithms that have been proposed in the past and to more firmly establish the potential of Ba flux as a quantitative proxy to reconstruct past changes in marine productivity.