Abstract
In the Biodiversity World (BDW) project we have created a flexible and extensible Web Services-based Grid environment for biodiversity researchers to solve problems in biodiversity and analyse biodiversity patterns. In this environment, heterogeneous and globally distributed biodiversity-related resources such as data sets and analytical tools are made available to be accessed and assembled by users into workflows to perform complex scientific experiments. One such experiment is bioclimatic modelling of the geographical distribution of individual species using climate variables in order to explain past and future climate-related changes in species distribution. Data sources and analytical tools required for such analysis of species distribution are widely dispersed, available on heterogeneous platforms, present data in different formats and lack inherent interoperability. The present BDW system brings all these disparate units together so that the user can combine tools with little thought as to their original availability, data formats and interoperability. The new prototype BDW system architecture not only brings together heterogeneous resources but also enables utilisation of computational resources and provides a secure access to BDW resources via a federated security model. We describe features of the new BDW system and its security model which enable user authentication from a workflow application as part of workflow execution.