This review considers the energy flow through a tidal flat ecosystem in the western Wadden Sea. Based on available estimates of primary production, input of allochthonous organic matter, a s well as on consumption and production a t different trophic levels, a modified concept of energy flow is advanced. In the traditional concept the secondary level has mainly been quantified in terms of herbivorous macrobenthos with a n apparently excessive primary food supply, and with the higher trophic levels being food-limited. In our opinion, the importance of small a n d very small zoobenthos with a negligible biomass, but with a relatively high production, has hitherto been underestimated. This complex -in this review referred to a s 'small food web' -consists, in addition to bacteria, of microfauna, meiofauna, temporary meiofauna and small macrofauna. In our opinion these groups contr~bute far more to the consumption of primary food and to the production of food for small carnivores than is generally assumed i n food-chain studies conducted in the western Wadden Sea.