Exchange of materials between the North Sea and the Wadden Sea

Abstract Distribution and transport paths of particulate matter in the southern North Sea and the Wadden Sea are discussed. In the North Sea, the main direction of transport is along the Dutch coast to the north. Part of the material proceeds to the northern North Sea and a mud field is indicated as a first possible deposition site. Active deposition in this area has still to be proven. A specific characteristic of the suspended-sediment distribution in the North Sea is a zone of minimum turbidity between the salt maximum and the Dutch shore. This is considered to be the outer seaward boundary of the coastal zone from where appreciable amounts of settling material entering the Wadden Sea originate. Processes of accumulation of suspended matter in the Wadden Sea are discussed. It is shown that these are especially efficient in spring and summer. To support this conclusion the exchange of organic matter between the two regions is also taken into account.