The ARION system provides basic e-services of search and retrieval of objects in scientific collections, such as datasets, simulation models and tools necessary for statistical and/or visualization processing. These collections may represent application software of scientific areas, they reside in geographically disperse organizations and constitute the system content. The user may invoke on-line computations of scientific datasets when the latter are not found into the system. The underlying grid used consists of hardware and software resources in the various participating organizations. ARION manages these resources providing a computing framework that produces datasets required by the user. In addition, the system offers semantic description of its content in terms of scientific ontologies and metadata information. Thus, ARION provides the basic infrastructure for accessing and deriving scientific information in an open, distributed and federated system.