IsoTroph | University of Tübingen

IsoTroph: Advanced techniques in isotopic biogeochemistry for the estimation of fossil mammal trophic position

The principal objective of the IsoTroph project is to improve the geochemical method used in the paleontology of terrestrial mammals in detection of their trophic position. In particular, the project focuses on a difference in δ15N between single amino acids (glutamate and phenylalanine) that is then used to calculate the trophic discrimination factor (TDF). It is a quantitative parameter used in reconstructions of past animal or human trophic levels (a primary consumer level – a herbivore; a secondary consumer level – a carnivore feeding on herbivores; etc.), crucial for understanding the evolution of environments. The TDF has never been established before for terrestrial mammals, although it is a key parameter in modeling past ecology.

The main research method of the IsoTroph is the analysis of δ15N in selected amino acids in bone collagen of a predator's population and that of its prey. These results are then calculated into the TDF between these populations. To achieve this, the project will involve a study of modern populations (collections of recent bones of wolf, lynx, red fox, and their prey) and a collection of fossils from a Pleistocene carnivore den (cave hyena and its prey). These collections will provide insight into four species of mammalian carnivores, representing variable ecology (both hypercarnivores and omnivores) and different chronologies (recent and Pleistocene).