Carbon isotope fractionation between diet, breath CO2, and bioapatite in different mammals

The carbon isotope fractionation between tooth enamel bioapatite, breath CO2, and diet was measured for voles, rabbits, pigs, and cattle on controlled diets. The measured fractionation (expressed as isotope enrichment epsilon*) between enamel and diet was 11.5 +/- 0.3 parts per thousand, 12.8 +/- 0.7 parts per thousand, 13.3 +/- 0.3 parts per thousand, and 14.6 +/- 0.3 parts per thousand for these respective species. There is a 1: 1 correlation between epsilon*(breath-diet) and epsilon*(enamel-diet) (r(2) = 0.94, p < 0.01), whereas our data do not resolve significant inter-species differences in epsilon*(bioapatite-diet) are primarily a result of differences in findings are consistent with the hypothesis that inter-species differences in digestive physiology, rather than differences in the magnitude of fractionation between mineral and body fluid. (c) 2005 Elsevier Ltd. All rights reserved.