Light Isotope Systematics and Trophic Levels

In this notation, the ratio of 2H to 111 in the sample is compared to the same ratio in an internationally agreed standard material. If the ratio in the sample is identical to that in the standard, then the 8 value (82H, usually referred to as 8D 

Farquhar et al. (1982) showed that the carbon isotopic composition of plant material (813CP) as a result of photosynthesis can be expressed empirically as  

Plants are the base of the terrestrial food chain. The body tissue of herbivores feeding on these plants, and subsequently of omnivores and carnivores, is dependent on the isotopic composition of the plant material ingested, and therefore reflects the 813C values of either a C3 or C4 biome. The exact values are modified by metabolically induced fractionation as the food is digested and incorporated into different body tissues. At its simplest, it has been assumed 

Muscle, skin, bone, hair, internal organs 

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