The aim of the project is to provide a firm scientific basis for sustainable management and exploitation of the coastal fringe ecosystems in Eastern-Africa. The objectives of the project are: 1) to assess the nutrient sink or source function of mangroves in terms of nitrogen compounds, 2) to make a comparison of the functioning of seagrass meadows in 2 contrasting situations, with and without mangroves, 3) to elucidate the hydrodynamics of water circulation, 4) to study the biological diversity of the coastal zone and the population dynamics of economically relevant species. The reseach will be carried out in three locations: at Gazi Bay, in Kenya, on the East coast of Zanzibar, Tanzania and at Maputo Bay in Mozambique.