Seasonal patterns of bacterial production and biomass in intertidal sediments of the western Dutch Wadden Sea

[Methyl-³H] thymidine incorporation, bacterial abundance and biomass were measured over 1 yr on interdidal flats in the western Dutch Wadden Sea. Thymidine incorporation and biomass carbon production peaked in March and in mid-late summer with thymidine incorporation rates ranging from 15 to 15390 nmol l⁻¹ wet sediment d⁻¹ in the top 3 mm of sediment (0.4 to 518 mgC l⁻¹ wet sediment d⁻¹). Bacterial production was site-specific. The higher bacterial production at one site could be related to higher organic C sedimentation. At most sites bacterial production covaried with particulate organic carbon content and its decomposable fraction in the sediment, suggesting nutrient stress. Covariation of production with bacterial abundance and biomass was not found. The latter variables showed a distinct seasonality with lowest values in spring/summer and highest values in autumn. Regulation of bacterial density appeared to be strongly density-dependent.