The fluid dynamics of swimming by jumping in copepods
MetadataShow full item record
KeywordCopepod jump; Viscous vortex ring; Impulsive stresslet; Impulsive Stokeslet; Hydrodynamic camouflage; Non-dimensional ‘jump number’
Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic predators. We developed an impulsive stresslet model to quantify the jump-imposed flow disturbance. The predicted flow consists of two counterrotating viscous vortex rings of similar intensity, one in the wake and one around the body of the copepod. We showed that the entire jumping flow is spatially limited and temporally ephemeral owing to jump-impulsiveness and viscous decay. In contrast, continuous steady swimming generates two well-extended long-lasting momentum jets both in front of and behind the swimmer, as suggested by the well-known steady stresslet model. Based on the observed jump-swimming kinematics of a small copepod Oithona davisae, we further showed that jump-swimming produces a hydrodynamic disturbance with much smaller spatial extension and shorter temporal duration than that produced by a same-size copepod cruising steadily at the same average translating velocity. Hence, small copepods in jumpswimming are much less detectable by rheotactic predators. The present impulsive stresslet model improves a previously published impulsive Stokeslet model that applies only to the wake vortex.
Author Posting. © The Authors, 2010. This is the author's version of the work. It is posted here by permission of Royal Society for personal use, not for redistribution. The definitive version was published in Journal of the Royal Society Interface 8 (2011): 1090-1103, doi:10.1098/rsif.2010.0481.
Showing items related by title, author, creator and subject.
Heat shock protein expression during stress and diapause in the marine copepod Calanus finmarchicus Aruda, Amalia M.; Baumgartner, Mark F.; Reitzel, Adam M.; Tarrant, Ann M. (2011-03)Calanoid copepods, such as Calanus finmarchicus, are a key component of marine food webs. C. finmarchicus undergoes a facultative diapause during juvenile development, which profoundly affects their seasonal distribution ...
Copley, Nancy J.; Wiebe, Peter H.; Cowles, Timothy J. (Woods Hole Oceanographic Institution, 1989-07)Net tows were collected with a Multiple Opening/Closing Net Environmental Sampling System (MOCNESS) carrying twenty 1-m2 nets in October 1982 in and near warm-core ring 82-H in the North Atlantic (RV/Knorr cruise 98). ...
Almada, Amalia A.; Tarrant, Ann M. (2016-05)Copepods are abundant crustaceans that harbor diverse bacterial communities, yet the nature of their interactions with microbiota are poorly understood . Here, we report that Vibrio elicits targeted transcriptional ...