Karp-Boss, L. University of Washington, leekarp@ocean.washington.edu
Jumars, P. University of Washington, jumars@ocean.washington.edu
Boss, E. Oregon State University, boss@oce.orst.edu

Small scale turbulence could be highly significant to dinoflagellate motility by affecting cell trajectories through dispersion and disorientation. In this study, effects of shear flow on swimming trajectories and orientations of individual dinoflagellate cells and chains were studied in a Couette flow. Shear effects varied between species. Whereas cells of Glenodinium foliaceum maintained their random swimming orientations upon exposure to shear, swimming orientations of both single cells and chains of Alexandrium catenella were affected. The magnitude of the effect increased with shear rate. An important question for modeling effects of turbulence on dinoflagellates is whether swimming motion of dinoflagellates in the presence of shear flow can be described accurately by simple superposition of the flow and the swimming motion in the absence of flow. The assumption of simple superposition has been commonly used in models to asses effects of turbulence on vertical migration of dinoflagellates and on predator-prey interactions. Results of our study suggest that some dinoflagellates may actively react to the presence of shear by altering their swimming behavior, and thus their motion in shear flow cannot be described by simple superposition.
Day: Tuesday, Feb. 2
Time: 11:15 - 11:30am
Location: Hilton of Santa Fe
Code: SS02TU1115H