Sulfur isotopic budget

Figure 12.5 Sulfur isotopic budget based on mass isotopic fluxes (bar graphs) and their isotopic composition on a monthly basis in coastal marine sediments of cape Lookout Bight, NC (USA). Units are in mol S m-2 m-1. (Modified from Chanton and Martens, 1987b.)...

Chanton, J.P., and Martens, C.S. (1987b) Biogeochemical cycling in an organic-rich coastal marine basin. 8. A sulfur isotopic budget balanced by differential diffusion across the sediment-water interface. Geochim. Cosmochim. Acta 51, 1201-1208. 

Hydrogen sulfide, H2S (J]H2S = [H2S] + [HS ] + [S2 ], where [HS ] represents ca. 80% at pH 7.5-7.65 in the Black Sea anoxic interior), is the key chemical compound that defines the direction and origin of many biogeo-chemical cycles in the anoxic zone of the Black Sea. The main goal of this review is to present the contemporary inventory of hydrogen sulfide and sulfur intermediate species, the results of recent physiochemical studies of the bottom convective layer, and to discuss the sulfur isotopic composition of dissolved sulfide and sulfate. This review concludes by presenting the sulfur budget of the Black Sea. 

Leung, Colussi and Hoffmann have used isotopic analysis in an attempt to constrain the amount of sulfate that could be produced by Crutzen s mechanism [129,130]. The first study retrieved the concentration profiles of OC S and OC S from infrared transmission spectra of the atmosphere recorded by the NASA MkIV balloon-borne interferometer. They derived an enrichment factor of 73.8 zb 8.67oo defined such that photolytically generated sulfur would be enriched in An isotopic budget based on this result shows that OCS photolysis cannot be a significant source of sulfate aerosol, since the enrichments of OCS, sulfuric acid aerosol and SO2 are known to be small [131]. A later laboratory study by the same group came to the conclusion that stratospheric photolysis results in an enrichment of 67 zb 77oo. 

Tomascak PB, Ryan JG, Defant MJ (2000) Lithium isotope evidence for light element decoupling in the Panama subarc mantle. Geology 28 507-510 Tomascak PB, Widom E, Benton LD, Goldstein SL, Ryan JG (2002) The control of lithium budgets in island arcs. Earth Planet Sci Lett 196 227-238 Tomaszak PB (2004). Lithium isotopes in earth and planetary sciences. Rev Miner Geochem Trofimov A (1949) Isotopic constitution of sulfur in meteorites and in terrestrial objects. Doki Akad Nauk SSSR 66 181... 

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