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Show 69 college of science Purpose: The purpose of this project is to calculate the stable carbon fractionation factor from enamel to diet(εenamel-diet) for an elephant, Loxondonta africana and a rhino, Ceratotherium simum, from the Hogle Zoo. Background: Stable isotope ratios recorded in enamel of tusks and teeth from herbivores can be used in diet reconstruction[1]. To reconstruct diets accurately one should take into account an accurate value for fractionation of carbon occurring between diet and enamel (ε*enamel-diet). For many herbivores this has not been calculated, but it has been demonstrated that the controlling factor is the degree of methanogenesis occurring within the digestive tract[2]. Controlled feeding studies have given ε*enamel-diet values for various herbivores[2], but for larger herbivores, such as elephants and rhinos, controlled feeding studies are not possible. It is important to find a fractionation factors for rhinos and elephants because they represent a significant portion of the fossil record. To find ε*enamel-diet we determined carbon stable isotope ratios (δ13C) of breath, and diet for both individuals. To determine the δ13Cdiet, δ13C for the feed, which constituted hay, pellets, and herbivore supplement, was measured, and a mixing model was used to calculate δ13Cdiet based on proportion of items in the diet. The δ13Cenamel-breath has been shown not to change significantly, so we used a previously determined value[2]. Using the equation ε*enamel-diet= ε*enamel-breat+ ε*breath-diet we determined a value for ε*enamel-diet. Results: The elephant gave a fractionation factor of 12.8 ‰ and the rhino of 13.2‰. Conclusions: These results fall within the predicted range of fractionation factors for non-ruminants. However the applicability of this data is called into question due to the small sample size, the use of captive animals, and the nature of feeding. Also the δ13Cdiet calculation makes the assumption that caretakers at the Hogle Zoo gave an accurate representation of proportion of foods in the diet. Future work to find fractionation factors could involve expanding to other large herbivores and sampling breath and enamel of other herbivores. Ackknowledgements Dr Nancy Carpenter, Associate director - Animal Health, Hogle Zoo Doug and Eric, and all other caretakers at the Hogle Zoo. Benjamin H. Passey. Assistant Professor, Johns Hopkins University Bruno Lavettre, engineer, Costech Analytical References [1] M.J. Kohn, T.E. Cerling, Stable isotope compositions of biological apatite, in: M.J. Kohn, J. Rakovan, J.M. Huges (Eds.), Phosphatesd-Geochemical, Geobiological, and Materials Importance, Reviews in Mineralogy and Geochemistry, vol. 48, Mineralogical Society of America, Washington, DC, 2002,pp. 455e480. [2] Passey, B., Robinson, T., Ayliffe, L., Cerling, T., Sponheimer, M., Dearing, D., Roeder, B., & Ehleringer, J. (2005). Carbon isotope fractionation between diet, breath co2, and bioapatite in different mammals. Journal of Archaeological science, 32, 1459-1470. doi: 10.1016/j.has2005.03.015 FINDING FRACTIONATION: CALCULATING THE STABLE CARBON FRACTIONATION FACTOR FROM ENAMEL TO DIET FOR ZOO HERBIVORES USING BREATH AS A PROXY Daniel Davis (Kevin Uno, Thure Cerling) Department of Biology, Department of Geology & Geophysics University of Utah UNDERGRADUATE RESEARCH ABSTRACTS Daniel Davis Thure Cerling |
