Stable carbon isotope analysis of amino acids and dietary fingerprinting
Seminar af Thomas Larsen fra Max Planck Institute for the Science of Human History
Info about event
Building 1540; Room K32 (In the basement just below ARC)
Stable carbon isotope analysis of amino acids is emerging as one of the most promising methods for reconstructing animal diets. Amino acids are powerful source biomarkers because animals must obtain half of the 20 proteinogenic amino acids directly from dietary sources. Since these essential nutrients can be synthesized by microbes and photosynthetic organisms only, essential amino acids (EAA) are passed from the bottom to the top of the food chain without alterations in their carbon skeletons. Work by my group has demonstrated that the EAA can be used for dietary fingerprinting because algae, bacteria, fungi and plants impart distinct d13CEAA patterns during biosynthesis. By comparing d13CEAA patterns of animals to their potential dietary sources it is possible to track food sources to genus level making this approach far more powerful than those based on bulk isotopes. d13CEAA fingerprinting is particularly well suited for archaeological or ecological studies of animals with inconspicuous feeding habits because food reference samples can be obtained from repositories and laboratory cultures. Thus, amino acid isotope analysis holds much promise for inferring trophic linkages, but the methodological requirements and potential pitfalls are much greater compared to bulk isotope analysis. To discuss workarounds, I will present an ongoing food web study on Arctic seabirds where I will highlight the importance of collaborating across multiple labs for quality assurance and relying multiple lines of evidence from direct observations to bulk and compound specific isotope analyses.