Abstract
A dinoflagellate Symbiodinium swims forward by using its transverse flagellum. The propagating wave of the transverse flagellum generates torque of the swimming direction. From this fact, the cell body is assumed to rotate to the opposite direction of the wave propagation to balance the total torque. In this study, the rotational direction was observed to compare with the previously obtained numerical result. Because the transparent cell body is difficult to determine whether the cell body is in the front or back of the focal plane of the objective lens, we conducted the biplane observation, where two objective lenses are focused on a single cell. The observed rotational direction was opposite to that in the prediction.
