The Trace Metal Geochemistry of Suspended Oceanic Particulate Matter
Abstract:
Vertical profiles of suspended particulate trace metals were measured in the Sargasso Sea near Bermuda and in the California Current, northwest Pacific. Using a new in situ pump, sufficiently large samples of particulate matter order 10mg were collected to allow measurement of a suite of trace metals as well as major component elements, using several different leaching techniques on separate subsamples. Concentrations of particulate Copper, Zinc, Cobalt, Cadmium, Nickel, and Lead near Bermuda were determined to be substantially lower than estimates based on previously published work. Concentrations of the more abundant elements Aluminum, Fe, and Mn were similar to previous estimates. Vertical profiles of Mn, Co, Pb, Zn, Cu, and Ni moll at Bermuda displayed similar features a relative depletion in surface waters, a relative maximum in the upper thermocline, and relatively constant deep water concentrations. The similarity in the vertical variations of dissolved particulate fractionation for these metals may be caused by interaction of dissolved metals with authigenic Mn phases the fractionation is anti-correlated with other major particle components organic carbon, calcium carbonate, opal, and aluminosilicate. The vertical profile of particulate Cd displayed a different form enrichment at the surface and decreasing concentrations through the thermocline to constant deep water values. Theses.