Carbon and other nutrients are subject to internal fluxes and processes within the North Sea ecosystem, like internal recycling of organic and inorganic compounds, uptake by phytoplankton, mineralisation, atmospheric efflux, sedimentation, etc. Recent data for the North Sea, concerning this internal recycling are very limited. In this project the relative importance of major processes involved in these internal carbon and nutrients cycles in the Southern Bight of the North Sea will be studied. These data will be integrated in box-models and compared to the input and output fluxes of C-N-P, in order to be able to visualise the global functioning of the concerned ecosystem. Furthermore, the significance of the main C-N-P compounds will be studied. more