ABSTRACT

Vertical profiles of ⁹Be and ¹⁰Be have been determined in the ocean. The nutrient-like recycling behavior for both Be isotopes, involving surface scavenging and deep-water regeneration, is manifested by their vertical profiles in the borderland basin off southern California, in the Pacific and in the Bering Sea. In contrast, in the western N. Atlantic, the concentrations of ⁹Be are almost vertically constant (or slightly higher in the surface than in the deep), and the concentrations of ¹⁰Be generally show minor surface depletion and are lower than those of the Pacific. The ⁹Be profiles in the S. Atlantic are generally similar to those of the Pacific except for a station close to the plume of Saharan desert dust, which shows surface enrichment. We interpret the vertical distributions and their differences among stations in terms of intense surface ⁹Be input (especially eolian input) to the Atlantic, a relatively uniform oceanwide pluvial input of ¹⁰Be, the particle reactive nature of Be, and the oceanic residence time of Be. Material balance calculations using a two-box (coastal and open oceans) model point to the importance of coastal ocean as a sink for both Be isotopes and eolian dusts as a source of oceanic ⁹Be.