1Ecology, Evolution, and Environmental Biology Department, Columbia University, 2Department of Anthropology, University of Notre Dame, 3Department of Sociology, Anthropology, & Social Work, University of South Alabama, 4Department of Sociology, Quinnipiac University
Saturday 21, Clinch Concourse
Stable isotope analysis of bone collagen is a useful tool for dietary reconstruction, with several extraction methods currently in use. Often, the results obtained are assumed to be equivalent, but it is not clear whether differing methodologies in fact yield analogous results. In order to test the effect of collagen extraction methods on stable isotope analysis, δ13C and δ15N ratios were obtained from the mandibles (n=15) of individuals interred at the Byzantine (5th-7th c. AD) St. Stephen’s monastery in Jerusalem, using methodologies developed by Ambrose and Schurr. These procedures were hypothesized to (a) produce statistically similar collagen yields and isotope ratios, and thus (b) generate the same interpretations with regard to diet.
There was no statistically significant difference between the two methods for collagen yield (Wilcoxon: p=0.7), or for carbon or nitrogen stable isotope ratios (Wilcoxon: δ13C p=0.5; δ15N p=0.7). Mean δ13C values (Ambrose: -18.7 ± 0.4‰; Schurr: -18.6 ± 0.6‰) were consistent with a primarily C3-based diet, while average δ15N ratios (Ambrose: 9.1 ± 1.2‰; Schurr: 9.2 ± 1.2‰) suggested some influence of animal and/or marine protein but represent an incomplete trophic level increase relative to faunal data. This comparative study indicates the Ambrose and Schurr methods are comparably effective for diet reconstruction of archaeological samples and that the differences in procedure do not affect subsequent interpretation.
This research was supported by the National Science Foundation-Research Experiences for Undergraduates (SES #1005158) Bioarchaeology Program at the University of Notre Dame.