Between September 1992 and September 1966, a subtidal sand bar in the main tidal inlet of Sylt-Römö Bight in the northern Wadden Sea was sampled for macrobenthos and sediment composition twice a year in spring and autumn. During each sampling date, six replicate box cores (0.02 m²) were collected from each of 4 subsites. The granulometric composition of the superficial sediment layer was analysed by mechanical dry sieving.