AbstractOver a course of one year total oxygen consumption of sediment cores was determined for the period of one week in a laboratory flow‐through system. The cores were collected during different months of the year and at two localities. One of the areas of investigation, at about 1 m water depth near the beach, had a carbon demand of 160 g C/m2/year. The other one, at a water depth of 11 m–a very heterogeneous sediment with a large gravel fraction — had a carbon demand of 100 g C/m2/year. As additional parameters for characterization of the sediments and interpretation of the determined metabolic rates particulate organic carbon and nitrogen, ATP, chlorophyll and pheopigments, bacterial counts and fauna composition were used. Both areas can be described as non detritus‐accumulating se