Beryllium isotopes in the ocean.

Abstract

Vertical profiles of 9Be and "Be 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 "Be generally show minor sur face 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 ocean wide pluvial input of "Be, 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.

Records of cosmogenic radionuclides 10Be, 26Al and 36Cl in corals: First studies on coral erosion rates and potential of dating very old corals

“…The 10 Be/ 9 Be ratios are within a narrow range, 6 ϫ 10 Ϫ9 to 3 ϫ 10 Ϫ8 , relative to the much larger range in 10 Be concentrations (range of 50ϫ). These ratios are quite consistent with those observed in seawater (Kusakabe et al, 1987;Ku et al, 1990;Kusakabe et al, 1990). There is a systematic trend in the 10 Be/ 9 Be ratios (which range between 4 ϫ 10 Ϫ8 and ϳ2 ϫ 10 Ϫ7 ) along advective flow lines (Ku et al, 1990) from surface N. Atlantic (4 ϫ 10 Ϫ8 ) to surface Pacific (2 ϫ 10 Ϫ7 ).…”

River fluxes to the sea from the oceanʼs 10Be/9Be ratio

“…600-1000 years, the ratio differs between ocean basins (e.g. Bourlès et al, 1989;Brown et al, 1992;Frank et al, 2009;Kusakabe et al, 1990;von Blanckenburg et al, 1996). Correspondingly, dissolved 10 Be/ 9 Be ratios in seawater are lowest in the Mediterranean Sea, a small ocean basin dominated by high terrigenous input and limited exchange with the global ocean; and highest in the Pacific, which collects a large flux of meteoric 10 Be over its vast surface area while receiving comparatively low terrigenous input given the size of the ocean basin.…”

Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and 10BE

“…Lithogenic input from continents, such as by aeolian dust or riverine pariculate matter, is the primar source of 9Be in marine sediments (e.g., Kusakabe et al, 1990Kusakabe et al, , 1991Brown et al, 1992;Wang et al, 1996). In subducting sediments and oceanic crust, white mica is thought to be the dominant mineral host of Be (Domanik et al, 1993;Bebout et al, 1993Bebout et al, , 1999.…”

“…At margins, the increased paricle flux scavenges lOBe equivalently throughout the water column (Lao et al, 1993), reducing the residence time to less than 100 yrs (Kusakabe et al, 1990;Anderson et al, 1990;Lao et al, 1992). The magnitude of this effect results in approximately 70% of the total lOBe introduced to the Pacific accumulating in margin sediments covering only 10% of the ocean floor (Lao et aI., 1992).…”