Simplified architecture of Sealife. A user browses a web page in which biological terms have been identified and annotated with semantic hyperlinks. When the user selects a link the Sealife server adds the associated term to the user's personal 'shopping cart' (CART). The Task Composition Manager (TCM) dynamically discovers services that require inputs of the same semantic type as those in the CART. The user can choose to execute any of these services through the TCM, and the result is presented by the browser.