Stable Isotope Sourcing using Sampling Erhardt, EB, BO Wolf, M Ben-David, and EJ Bedrick Open Journal of Ecology 4 (6) pp. 289–298 Online: May 2014 http://www.scirp.org/journal/PaperInformation.aspx?PaperID=46187 DOI: 10.4236/oje.2014.46027 Abstract Stable isotope mixing models are used to estimate proportional contributions of sources to a mixture, such as in the analysis of animal diets, plant nutrient use, geochemistry, pollution, and forensics. We describe an algorithm implemented as SISUS software for providing a user-specified number of probabilistic exact solutions derived quickly from the extended mixing model. Our method outperforms IsoSource, a deterministic algorithm for providing approximate solutions to represent the solution polytope. Our method is an approximate Bayesian large sample procedure. SISUS software is freely available at StatAcumen.com/sisus and as an R package at cran.r-project.org/web/packages/sisus.