Vertically, nematode species showed depth distributions that were indicative of sediment characteristics related to the site-specific hydrodynamic regime. Pronounced vertical segregation of nematode species was observed within sandy sediment under strong hydrodynamic and food-stressed conditions. A surface-dwelling nematode community of large predatory enoplids was separated from a deposit feeding xyalid-microlaimid community in deeper sediment layers (beneath 2 cm). Causal factors for this segregation are thought to be species interactions, feeding strategies and/or physical disturbance. In the finest sediments, with high silt content, almost all nematode species were confined to the upper sediment layers (1.5 cm). A sharp decline in density and diversity with depth was observed. Key factors for this distribution pattern are possibly related to the limited oxygen penetration in surface layers and the occurrence of sulphide in deeper sediment layers. At intermediate hydrodynamic and granulometric conditions, a gradual shifting of nematode community was observed with depth, with dominant nematode species maxima present at specific depth layers.