The Distribution ofNucula Turgida(Bivalvia: Protobranchia) From Dublin Bay, Ireland, and the Effect of Sediment Organic Content

Abstract

Recent investigations (Walker & Rees, 1980; Davis & Wilson, 1983b) have shown that the protobranch bivalveNucula turgida(Leckenby and Marshall) occupies an important niche in the ecology of Dublin Bay, where it is the dominant organism over much of the southern part of the outer bay. This is an area of moderately sorted fine sand (Harris, 1980) with a pelite (silt and clay) fraction of less than 10% and a consequently low percentage of organic matter of around 1% (Davis & Wilson, 1983b). Trevallion (1965) described theN. turgidahabitat as one of firm muddy sand, adding that the animals avoided mud due to their inability to maintain position or feeding and respiratory currents and also avoided gravel due to their inability to burrow in coarse substrates.