LIPIDS’ INFLUENCE ON CARBON ISOTOPIC SIGNALS FROM COLLAGEN SAMPLES OF TERRESTRIAL HERBIVORES

CELESTE T. SAMEC; AUGUSTO TESSONE; ERNESTO GALLEGOS; HÉCTOR PANARELLO

Brasilia, Brasil

Simposio; VII SSAGI - South American Symposium on Isotope Geology; 2010

Lipids are depleted in 13C stable isotope, in relation to proteins such as collagen, and carbohydrates (Post et al. 2007, Logan et al. 2008). In the use of carbon stable isotopes there are two scenarios in which this difference can lead to paleo-dietary misinterpretations or inaccurate food chain reconstructions. The first one is in relation to the variability of lipid content depending on several variables such as tissue’s location, species and environment (ie. terrestrial vs. marine) (Post et al. 2007). Numerous studies on ecology highlight the problems and the methods that deal with this variability in lipids contents (Sotiropoulos et al. 2004, Kiljunen et al. 2006, Post et al. 2007, Logan et al. 2008). The second problem arises in the context of archaeological or paleocological research involving samples with varying degrees of diagenesis that generate a differential preservation of lipids (Liden et al. 1995), particularly when these are compared with modern samples. Our study assess how lipid content affects the δ13C values on terrestrial mammalian herbivores’ bone collagen, having as a final goal to determine the magnitude of the bias that this biochemical compound can introduce into paleo-dietary interpretations. For this reason we compare the isotopic signal (δ13C‰) of 36 modern bone collagen samples, with varying degrees of preservation, against the same samples after being subject to lipid removal treatment.