The effect of feeding byYoldia limatulaon bioturbation

Abstract

Yoldia limatula is a dominant bivalve in shallow soft bottoms of boreal arctic seas of North America and Europe. This species is a subsurface and surface deposit-feeder. Yoldia's feeding activities result in sediment resuspension through expulsion of loose pseudofaeces directly into the water column. Expelled solids ranging between 10–200 times its body weight daily contain the finer fraction of sediment as pseudofaeces and elongate faeces. Thus feeding results in a fine sediment suspension, a pelletized sediment interface (unstable) and a coarse-grained subsurface. The amount of sediment resuspended was proportional to body size for Yoldia up to 18 mm. Larger animals still expelled greater quantities of sediment per expulsion, however, the frequency of expulsions decreased. The quantity of resuspended sediment was also positively correlated with water temperature above the feeding threshold of 6–8 °C. A 14 mm long Yoldia resuspended approximately 440 g of sediment (dry) each year. Secondary resuspension through destabilizing the sediment-water interface by Yoldia and other infauna is likely.