1. Observations of the physics of vertical and open boundary exchange in Regions of Restricted Exchanges (REEs), leading to improved parameterisation of these processes in research and simplified models. 2. Study of the phytoplankton and pelagic micro-heterotrophs responsible for production and decomposition of organic material, and of sedimentation, benthic processes and benthic-pelagic coupling, in RREs, with the results expressed as basin-scale parameters. 3. Construction of closed budgets and coupled physical-biological research models for nutrient (especially nitrogen) and organic carbon cycling in RREs, allowing tests of hypotheses about biogeochemistry, water quality and the balance of organisms. 4. Construction of simplified 'screening' models for the definition, assessment and prediction of eutrophication, involving collaboration with 'end-users', and the use of these models to analyse the costs and benefits of amelioration scenarios.