Using Continuously-Variable Leaching to Quantify Scavenged Particulate Phases in Marine Particles

Recent basin-scale datasets of multi-element particulate distributions in the oceans have shown statistical evidence that scavenged phases formed in situ—especially Fe- and Mn-oxyhydroxides, but also detrital biomass phases—contribute significantly to the ocean’s carrying capacity for trace elements. (E.g. Cd, Co, Cu, Fe and Mn, Ni, P, Pb, Sc, Th, Ti, V, Y, Zn.) Many such phases are only minor components of complex and variable marine particle assemblages, however, making them difficult to quantitatively assess in bulk samples. I present results from several continuously variable leaching schemes that demonstrate the finer-scale internal associations of trace elements in particles, both with one another and their putative particulate carrier phases. These leaching schemes seek to use individual samples to analytically confirm (or deny) the multi-element phase associations and stoichiometries evident over larger spatial scales.