This research is a new and detailed approach to the investigation of chemical scavenging processes in the Atlantic and Pacific Oceans, using the distributions of the rare earth elements (REE) as indicators of particulate removal and redox cycling under varying conditions of primary particle flux and water column structure. In situ pumping, will be used to collect large suspended particulate samples as part of an ongoing study of dissolved/particulate fractionation for a suite of major and minor elements. Established trace metal seawater sampling techniques will be used to collect REE water samples. The dependence of dissolved and particulate REE patterns and cerium anomalies on the mass concentration, composition, and vertical flux of the suspended particle field will be explored. This will be accomplished by profile measurements at four oceanographically distinct sites: 1) the productive Northeast Pacific margin environment, 2) the oligotrophic Northeast Atlantic, 3) the Gulf Stream/NW Sargasso Sea frontal system, and 4) the variably productive Central Equatorial Pacific. The REE will be used as probes of scavenging processes over spatial and temporal gradients in primary and new production. Results will have broad implications for the critical variables which regulate biological uptake, adsorptive scavenging, and redox-controlled removal of trace inorganics in open ocean and ocean margin environments.
