Between 10% and 40% of the Vanadium and Uranium entering the modern ocean as dissolved river input is eventually buried in sediments overlain by anoxic bottom water. Previous work by Dr. Emerson and his colleague Dr. Mix from Oregon State University has found that concentrations of V and U in foram tests have varied over the last 150 Kyrs. Provided the assumption is true that forams incorporate these metals in equilibrium with seawater, this preliminary data suggests that bottom water during the last glacial period was more oxygenated that at present, and that contrasts between Atlantic and Pacific bottom water was substantially different from that of today. In this renewal award the PIs will to continue their research in several directions: 1) they will perform culturing experiments with collaborator Dr. Erez in Israel to determine the uptake pattern of V and U in live forams; 2) they will improve solid source mass spectometry technique for measuring V and U insingle species of forams; and 3) they will apply these techniques to refine the history of anoxia in the world's oceans since the last interglacial.
