Effects of decalcification on bulk and compound‐specific nitrogen and carbon isotope analyses of dentin

Abstract

Decalcification is not needed to measure bulk isotope values in dentin from this modern odontocete, probably because the lipid and carbonate concentrations are low and the carbon isotope values of dentin protein and carbonate are similar. This method should not be applied in some cases (e.g., with fossil dentin and modern bone). Decalcification should still be used prior to CSIA since significant matrix issues occur with raw dentin processing and decalcification does not alter the amino acid molar composition or isotopic values of dentin.

Compound‐specific amino acid δ15N values in archaeological shell: Assessing diagenetic integrity and potential for isotopic baseline reconstruction

“…The close correspondence of the CSI‐AA patterns that we observed in most samples of both fossil and modern shell with CSI‐AA patterns in soft tissue, coupled with the low and generally similar ΣV values, clearly indicates that this protocol does not measurably fractionate individual AA isotope ratios. This finding is in contrast to recent work testing CSI‐AA patterns using different modes of demineralization for phosphate‐rich dentin . This work by Brault and coauthors indicated that when phosphates are present, all inorganic ions must be removed in order to produce the expected CSI‐AA patterns, and also to obtain reproducible δ 15 N AA values.…”

“…While the Trophic AAs are not used for baseline reconstruction, they are key for the reconstruction of paleo‐food web structures . Given the identical hydrolysis conditions, and the close match of the Source AA group values, it seems unlikely that these offsets are linked to sample preparation, a conclusion supported by recent CSI‐AA method tests with decalcification and hydrolysis of tooth material . Furthermore, recent data from deep‐sea corals has also documented similar offsets between soft tissue and structural protein skeleton, again only in the Trophic AA group (McMahon, personal communication).…”

Annual variability in dentin δ15N and δ13C reveal sex differences in weaning age and feeding habits in Risso's dolphins (Grampus griseus)

“…, Brault et al . ), therefore the decalcification process was assumed to have negligible effect on isotope ratios.…”

Effects of acidification on the isotopic ratios of Neotropical otter tooth dentin

“…However, there is a decrease in the mean δ 13 C values after the first acidification technique and a small increase after the second one. The inorganic carbon is more enriched in 13 C than the organic carbon, so decreases in δ 13 C values indicate that the inorganic carbon was removed from the tissue. A decrease in C:N ratios can be evidence of the elimination of inorganic carbon as well, as observed in the present study.…”