TY - GEN A1 - Tütken, T. A1 - Tatzel, Michael A1 - Vogl, Jochen A1 - Rosner, M. T1 - Assessing δ26Mg in bioapatite as proxy for faunivory N2 - Knowledge about feeding behavior is essential to determine trophic interactions and reconstruct predator-prey relationships in modern and past foodwebs. Traditionally, nitrogen isotopes (δ15N) of collagen are used to quantify the ingestion of animal protein, however collagen usually does not preserve over geological time scales. To infer the diet of extinct vertebrates from fossil material more resistant dietary proxies such as Ca and Mg isotopes are needed, which are major elements in the bioapatite of bones and teeth. Magnesium is a bio-essential element that replaces calcium in the bioapatite lattice and bone and enamel δ26Mg values of extant mammals increase systematically along the foodchain [1, 2]. The existing δ26Mg data, however, is scarce, in particular with respect to carnivores, thus still limiting the capability of this dietary proxy to reliably determine trophic differences between plant- and animal-feeders. To better constrain trophic-level effects recorded in Mg isotopes, we analyzed δ26Mg of bioapatite from modern mammals with a focus on faunivores, both carnivores and as yet unexplored insectivores. The trophic level effect of δ26Mg is influenced by the geological substrate which causes isotope variability in δ26Mg of faunal remains between different ecosystems [1, 2]. Therefore, as first-order proxy for sample provenance and to assess potential influences of the bedrock substrate of the animals´ habitats on δ26Mg of bones and teeth, we measured the 87Sr/86Sr on the same specimens. This information will enable us to refine trophic level effects and determine whether δ26Mg can be used to distinguish different faunivores isotopically. This will be of paramount importance for dietary reconstructions of trophic niches in fossil foodwebs. [1] Martin et al. (2014) Geochmica Cosmochimica Acta 130, 12-20. [2] Martin et al. (2015) Proceedings of the National Academy of Sciences 112, 430-435. T2 - Goldschmidt CY - Paris, France DA - 13.08.2017 KW - Magnesium stable isotopes KW - Isotope fractionation KW - Trophic level KW - 87Sr/86Sr KW - Provenance PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/41535 AN - OPUS4-41535 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany