|Calcimass and carbonate production by molluscs on the tidal flats in the Dutch Wadden Sea: I. The tellinid bivalve Macoma balthica|
Beukema, J. (1980). Calcimass and carbonate production by molluscs on the tidal flats in the Dutch Wadden Sea: I. The tellinid bivalve Macoma balthica. Neth. J. Sea Res. 14(3-4): 323-338
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
Production of shell-lime by the Macoma balthica population living on the tidal flats of the Dutch Wadden Sea was assessed from estimates of abundance, age composition and growth rates of the population during 11 years (1969 to 1980) at 15 sampling places on Balgzand, a 50 km² tidal flat area. Moreover, the whole 1300 km² of tidal flats of the Dutch Wadden Sea was surveyed once and partly twice in the period. Calcimass of the shells of the standing stock of Macoma amounted to an average of 24 g.m-2 on Balgzand and to 16 g.m-2 for all tidal flats. Mean annual turnover rate was 0.5 to 0.6 a-1. Mean annual values for elimination and production of Macoma carbonate amounted to about 13 g.m-2.a-1 for Balgzand and about 9 g.m-2.a-1 for all tidal flats of the Dutch Wadden Sea. During the first 6 years of the period of observation, when relatively high proportions of the animals were old, elimination surpassed production and the calcimass gradually declined. During the second half of the period the situation reversed and calcimass returned to nearly its initial level. Over the entire period elimination and production thus nearly balanced, though during separate years these 2 values could differ by a factor of 2. Annual variability arose from significant year-to-year differences in recruitment, death rates, growth rates and age composition of the population. Total annual carbonate production by Macoma on the 1300 km² of tidal flats of the Dutch Wadden Sea is estimated at about 11000 tons.