Reactive Radionuclides in the Eastern North Atlantic, Joint Global Ocean Flux Study This proposal requests renewed funding for a study of spatial variations in the distributions and particulate fluxes of a suite of naturally occurring radioactive nuclides, which was initiated as part of the North Atlantic Bloom Experiment of the Joint Global Ocean Flux Study (JGOFS). The radionuclides that are being measured serve as ocean tracers that can yield fundamental information about the rates of biogeochemical processes that govern the scavenging of reactive chemical species and the fate of biogenic particles in the oceanic water column. The study is designed to test the hypothesis that the uptake and release of soluble chemical species by particulate matter and the formation and destruction of particle aggregates in the oceanic water column occur at rates that vary both spatially and temporally in response to variations in the rate of plankton production at the sea surface and the flux of organic matter leaving the surface layer. The data will be interpreted within the context of biological rate measurements and other data that are being collected within the international JGOFS program and will be used to test biogeochemical models. This study is expected to contribute to a better understanding of particle fluxes and dynamics in the ocean, issues that are of broad concern to marine chemistry, biology and geology. //
