Application of particle image velocimetry to the study of suspension feeding in marine invertebrates

Planar (2 dimensional) particle image velocimetry (PIV) was compared against the established clearance rate method of estimating bulk flow through suspension-feeding organisms to evaluate PIV as a technique to estimate feeding activity. The study of ciliary pumps has relied on advances in technology, as it is difficult to access the pump without excessively disturbing the animal. We used PIV to examine feeding velocities in five species of suspension-feeding, benthic invertebrates including one ascidian (Styela clava) and four bivalves (Mytilus edulis, Crassostrea virginica, Argopecten irradians and Mercenaria mercenaria). In calibration experiments using pipes of varying diameters, we were able to resolve flow with >98.5% accuracy. We extended the pipe model to study water processing in the mussel M. edulis. Both velocity and bulk flow through the mussel changed in predictable ways in relation to clearance rate (P<0.05). Application of PIV to the Study of suspension feeding will further our understanding of the behavior and physiology of economically- and ecologically-important organisms.