Doctoral Dissertation Research: Doctoral Dissertation Research: Reconstructing metabolism and physiology through analysis of transition metal isotopes

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

Several different elements with specific chemical signatures, or isotopes, have been measured in bones of living and fossil species to help researchers reconstruct information regarding diet, migration, and reproduction. The measurement of stable isotopes of transition metals such as zinc, iron, and copper, could also be applied to the study of living or fossil primate bone to provide additional insight into these factors. This project measures transition metal isotopes in bone from primate individuals, and links them to information known from these individuals during life, to better understand how these markers might help reconstruct information about meat consumption and infant feeding patterns from fossilized bone. The results of this project also provide information about how individual- and sex-specific differences in metabolism influence these measurements. This is a multi-institutional collaborative project that includes mentoring of undergraduate students from groups underrepresented in STEM, community outreach, and presentations to local schools. This research has three main aims: 1) Are the breastfeeding and weaning patterns of primates recorded by δ66Zn values in enamel bioapatite and bone? 2) How does infrequent meat consumption affect the δ66Zn values measured in bioapatite? 3) Do sex- related differences in Fe and Cu fractionation occur in primates and does the degree of female reproductive investment affect these values? Analytic approaches include transition isotope analysis using mass spectrometry, and the application of a logistic regression with a machine learning algorithm to predict diet category (frugivorous/herbivorous or omnivorous/meat consuming) and trophic position of the samples. Transition metals (Zn, Fe, Cu) have the potential to be indicators of trophic position (δ66Zn), sex and reproductive state (δ56Fe and δ65Cu) in prehistoric and even fossil skeletal elements with poor organic preservation. This study aims to establish a reference dataset for nonhuman primates that serves as the first application of this technique in wild primates, with the potential to dramatically expand the use of transition metals in archaeological science. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.