The food web of organisms living in or in the bottom of coastal waters is generally dependent on the pelagic food web through the sinking of living and dead (detritus) organic matter. Only in the shallow and tidal areas primary production by benthic diatoms on the sediment is an important food source. The sinking from the pelagic is affected by various processes. The first process is the passive sedimentation of partulates (zooplankton faecal pellets, diatoms skeletons), the second one is the active filtration of organic matter from the water by suspension feeders such as bivalves (mussels, oysters). Especially food of high quality such as the sinking diatoms from the spring bloom is eagerly used by these organisms.

The small food web in the sea-bottom is represented by the aerobic and anaerobic bacteria and the
meiobenthos (1-5 um). The model contains 4 macro-benthos groups which are of similar size but have distinct functions in the system. Besides the suspension feeders we defined deposit-feeders, living in the sediment and grazing on benthic diatoms, bacteria and meiobenthos, infaunal predators, also living in the sediment but preying on deposit and suspension feeders and epifaunal predators, living on the sediment and mainly preying on filter feeders. In areas without benthic primary production the main input for the food web in the benthos is detritus, used by the bacteria as their main food source. There the bacteria form the basis of the food web in the benthic system. The higher trophic levels in the benthos are indirectly fed by these bacteria. In the model we limit ourselves to a coarse division in functional groups, ignoring the large variance in size even within a species.