Meeting Abstract
Flagella are crucial to the interactions of many unicellular organisms with their surrounding aquatic environment. The dinoflagellates have a unique but remarkably conserved flagellation morphology: a trailing longitudinal flagellum and an exquisitely complex transverse flagellum that encircles the cell. What are the selective advantages offered by this arrangement? We investigate the dinoflagellate design in silico using a high-performance regularized Stokeslet boundary element method and combine these simulations with particle image velocimetry (PIV) observations of dinoflagellate-generated flow fields and swimming kinematics. We find that the helical transverse flagellum provides most forward thrust and, despite its near-cell position, is more hydrodynamically efficient than the trailing flagellum; however, the latter is nonetheless required to enable steering. Flagellar hairs and the sheet-like structure of the transverse flagellum allow dinoflagellates to exert strong propulsive forces and maintain high clearance rates without extending a long conventional flagellum far into the surroundings. This unique morphology has thus been essential to the evolution of the generally large, fast-swimming dinoflagellates.
