Meeting Abstract
Most ctenophore species generate propulsion exclusively by the metachronal motion of rows of long ciliary plates (ctenes). These propulsors serve to control orientation, capture prey, perform escape maneuvers, and maintain position in the water column in spite of exposure to varying levels of turbulence and a variety of flow conditions. We were motivated to test the limits of this unique locomotor system in complex flows, both to improve our understanding of ctenophore ecology and behavior and to draw potential inspiration for new propulsion technologies at the millimeter/centimeter scale. From 3D kinematic measurements in a pseudokreisel tank, we found that the ctenophore Pleurobrachia bachei maintained an “upward” orientation and occupied all available space in low-shear flow, whereas animals displayed a “downward” orientation and shifted to the edges of the tank as shear increased. We also measured 2D kinematics of animals in a small speaker-driven turbulence tank, finding that animals increasingly congregated at the bottom of the tank in high turbulence. Both flows were quantified using 2D particle image velocimetry (PIV). Our results inform studies of ctenophore ecology and distribution, supporting previous findings of turbulence-avoidance behavior and quantifying ctenophore agility and maneuverability for potential future development in bioinspired vehicle applications.
