Stable isotopic compositions dioxide

We report here measurements of the stable hydrogen Isotopic composition of methane and water, the stable carbon Isotopic composition of methane and carbon dioxide, and ancillary parameters from several freshwater environments and from a few locations within the Tampa Bay estuary. The stable Isotopic compositions determined In this study are reported as a parts-per-mll ( /oo) deviation (5) from a standard with a known stable isotopic ratio. The definition of the 6 value Is ... 

Hypothesis 3, Diffusion of DIC together with DOC, sulfate, and cations from confining bed pore waters to the Black Creek aquifer provides sources of electron donor (organic carbon) and electron acceptor (sulfate) for microbial metabolism and additional inorganic carbon to drive low-magnesium calcite precipitation. The combination of magnesium-calcite dissolution from shell material driven by microbially produced carbon dioxide, and the precipitation of more thermodynamically stable low-magnesium calcite cement in the aquifer, can explain major ion and carbon isotope composition of Black Creek aquifer water. 

Homibrook E. R. C., Longstaffe F. J., and Fyfe W. S. (2000) Evolution of stable carbon isotope compositions for methane and carbon dioxide in freshwater wetlands and other anaerobic environments. Geochim. Cosmochim. Acta 64, 1013-1027. 

The biotic activity of organisms is accompanied by the fractionating of the isotopic composition of carbon dioxide. Vladimir Vernadsky (1926) predicted this effect before the first experimental evidence became available. It is known that the carbon of terrestrial reservoirs consists of two stable isotopes and supplemented with small quantities of C radioactive species (T i/2 = 5730 years). For more details on this fractionation see Chapter 2, Box 6. 

Horibe Y, Shigehara K, Takakuwa Y (1973) Isotope separation factor of carbon dioxide-water system and isotopic composition of atmospheric oxygen. J Geophys Res 78 2625-2629 Horita J (1989) Stable isotope fractionation factors of water in hydrated saline minerals-brine systems. Earth Planet Sci Lett 95 173-179... 

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