Project:	Determining trophic enrichment factors for birds and reptiles
Disciplines:	Multidisciplinary, Geochemistry, Geobiology
Mentor:	Julia Tejada, Assistant Professor, (GPS), jtejada@caltech.edu
Mentor URL:	https://juliatejada.caltech.edu/  (opens in new window)
AO Contact:	Mattia Tagliavento, mattiat@caltech.edu
Background:	The isotopic composition of animal tissues (e.g., bones, eggshells, teeth) is directly influenced by the isotopic composition of the consumed diet. However, during incorporation of elements (e.g., carbon, nitrogen) from diet to tissues, kinetic isotope effects associated with physiological processes change the isotopic ratios of the ingested food to that ultimately expressed in tissues. Determining the exact offset (or TEF, Trophic Enrichment Factor) between the isotopic compositions of hard tissues and ingested food is crucial for paleobiological investigations.
Description:	The student will determine the stable isotope ratios (carbon, nitrogen, oxygen) of a selection of animal samples (eggshells and/or teeth) and their associated ingested food. The student will then interpret the obtained results using a set of statistical methods. This project is an opportunity to gain relevant experience in different aspects of geochemical analyses, including sample preparation, analysis in a mass-spectrometer, and data interpretation.
References:	Tejada-Lara, J. V. et al. Body mass predicts isotope enrichment in herbivorous mammals. Proc. R. Soc. B 285, 20181020 (2018). Cullen, T. M., Longstaffe, F. J., Wortmann, U. G., Huang, L. & Evans, D. C. Anomalous 13C enrichment in Mesozoic vertebrate enamel reflects environmental conditions in a “vanished world” and not a unique dietary physiology. Paleobiology 1–15 (2023) doi:10.1017/pab.2022.43.
Student Requirements:	Basic knowledge on statistics, biology, and chemistry. Must be willing to work in a dusty environment (paleontological lab) and with chemicals (wet chemistry lab).
Programs:	This AO can be done under the following programs:   Program    Available To        Amgen Scholars    Non-Caltech students only          SURF    both Caltech and non-Caltech students  Click on a program name for program info and application requirements.