Secondary production of an intertidal mussel bed community related to its storage and turnover compartments

Macrofaunal b ~o n ~a s s and production were studied at 6 sites on an intertidal mussel bed in the northern Wadden Sea near the island of Sylt (North Sea) in 1984 Mean biornass of the community w a s about 25 times h ~g h e r (1243 g AFDW m-') than in other commumties of the Wadden Sea Of t h s biomass, 97 % was represented by the mussel M y t ~l u s e d u l ~s L Although associated fauna had a share of only 3 %, their absolute biomass of 35 g AFDW m-' is in the range reported for other intertidal communities of the Wadden Sea Annual producbon of the rnacrofaunal community (468 g AFDW m-2 yr-') was dominated by n~ussels (436 g AFDW m-2 yr-') P/B-rabo was very low for the total community (0 36) Annual production of associated macrofauna was much lower (31 g AFDW m-'yr-') but the P/Bratio (0 89) indicates a higher turnover rate Suspension feeders had the greatest share in secondary production followed by grazers Predators and detr~tus feeders were of lesser importance Biomass and production of individuals of higher mass dominated overwhelmingly over smaller size groups The main productive potential of the communlty is formed by the larger size classes These are of only minimal importance for predation Therefore the communlty can be divided into 2 functional compartn~ents (1) a storage compartment with a high productive potenbal leading to further increase in biomass or being spent for metabolic and reproductive requirements and (2) a turnover compartment with relatively low biomass and production but higher turnover The production of the turnover compartment is available to most predators