COSYNA's focus is on the North Sea Coasts, Arctic Coasts, and the Global Coast. The North Sea is a shallow shelf sea in Northern Europe characterized by complex interdisciplinary processes governing a large range of interconnected length and time scales. The North Sea is one of the best investigated shelf sea areas, but we are only slowly beginning to understand the interconnected forces that govern energy budget, material fluxes, and the factors directly controlling ecosystem dynamics. Tidal exchange flows with the extensive intertidal mudflats of the unique World Heritage Site Wadden Sea dominate circulation, turbidity, and productivity of large areas of the German Bight, while contributing to global carbon and nitrogen cycles. At the same time, long-term changes of temperature and ocean acidification due to global change become more and more evident. Since the North Sea is surrounded by densely populated, highly-industrialized countries, it is influenced by multiple, often conflicting uses, such as fisheries, waste disposal, oil drilling, transportation, coastal defense, offshore wind farms, or recreation.