atural carbon consists of two stable isotopes, viz. C-13 (1.11%) and C-12 (98.89%). Carbon-13 is an important isotope as a tracer in chemistry, life sciences, medicine and biochemical synthesis. Although the current world production of C-13 at 90% concentration is about 10 kg per annum, an optimistic projection of hundred fold increase in the market demand is anticipated in view of rapid develo...

Stable isotope analysis of feces can provide a non-invasive method for tracking the dietary habits of nearly any mammalian species. While fecal samples are often collected for macroscopic and genetic study, stable isotope analysis can also be applied to expand the knowledge of species-specific dietary ecology. It is somewhat unclear how digestion changes the isotope ratios of animals' diets, so...

BACKGROUND The natural ratios of carbon (C), nitrogen (N), and sulfur (S) stable isotopes can be varied in some specific living organisms owing to various isotopic fractionation processes in nature. Therefore, the analysis of C, N, and S stable isotope ratios in ginseng can provide a feasible method for determining ginseng authenticity depending on the cultivation land and type of fertilizer. ...

The largest biological fractionations of stable carbon isotopes observed in nature occur during production of methane by methanogenic archaea. These fractionations result in substantial (as much as approximately 70 per thousand) shifts in delta(13)C relative to the initial substrate. We now report that a stable carbon isotopic fractionation of comparable magnitude (up to 70 per thousand) occurs...

The enzymic fractionation of the stable carbon isotopes of CO(2) (Deltaco(2)) was determined using a purified preparation of ribulose-1,5-bisphosphate (RuBP) carboxylase isolated from cotton (a C(3) plant) leaves. The bicarbonate concentration in the reaction mixture saturated the enzyme and furnished an infinite pool of (12)CO(2) and (13)CO(2) for enzyme fractionation. The RuBP was 96 to 98% p...

Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn) is found in bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report...

The transport of carbon from land to ocean, via rivers, groundwater, and aerosols, is an important component the global cycle that must be known accurately assess anthropogenic CO2 storage on in ocean. Current budgets have adopted terrestrial inputs ocean ranging 0.5 GtC/yr 0.9 GtC/yr, derived mainly estimates riverine fluxes. However, these ignore coastal ecosystems through submarine groundwat...

The stable isotopes composition of chemolithoautotrophic cave ecosystems is known to differ from epigenic caves. Here we show that in addition, dead carbon (devoid 14 C), utilized and transferred throughout this ecosystem, rendering it unsuitable for radiocarbon dating. connectivity the Ayyalon Cave ecosystem with surface studied, along its sources energy carbon, as well interconnections betwee...