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This material had an anomalously high 13 C: 12 C ratio (0.0112372 [4]), and was established as δ 13 C value of zero. Since the original PDB specimen is no longer available, its 13 C: 12 C ratio can be back-calculated from a widely measured carbonate standard NBS-19, which has a δ 13 C value of +1.95‰. [ 5 ]
The δ 13 C of C3 plants depends on the relationship between stomatal conductance and photosynthetic rate, which is a good proxy of water use efficiency in the leaf. [19] C3 plants with high water-use efficiency tend to be less fractionated in 13 C (i.e., δ 13 C is relatively less negative) compared to C3 plants with low water-use efficiency. [19]
If an animal (or human) eats only C3 plants, their δ 13 C values will be from −18.5 to −22.0‰ in their bone collagen and −14.5‰ in the hydroxylapatite of their teeth and bones. [ 16 ] In contrast, C4 feeders will have bone collagen with a value of −7.5‰ and hydroxylapatite value of −0.5‰.
This template should always be substituted (i.e., use {}). Purpose This is a typing aid, used to provide "δ 13 C" in text for Delta C-13 isotopic ratios comparing Carbon-13 to the more common Carbon-12 , in isotope analysis .
Bulk carbon-13 for commercial use, e.g. in chemical synthesis, is enriched from its natural 1% abundance. Although carbon-13 can be separated from the major carbon-12 isotope via techniques such as thermal diffusion, chemical exchange, gas diffusion, and laser and cryogenic distillation, currently only cryogenic distillation of methane (boiling point −161.5°C) or carbon monoxide (b.p. − ...
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One of these, the standard for normalizing δ 13 C values, is Pee Dee Belemnite (PDB), a fossil which has a 13 C / 12 C ratio of 1.12372%. [3] δ 13 C for some sample is then calculated by dividing the amount of 13 C by 1.12372% and then subtracting 1 and multiplying by 1000 to give a value in "per mil". [4] A related standard is the use of a ...
[13] The δ 13 C value for animals depends on their diet. An animal that eats food with high δ 13 C values will have a higher δ 13 C than one that eats food with lower δ 13 C values. [9] The animal's own biochemical processes can also affect the results: for example, both bone minerals and bone collagen typically have a higher concentration ...