Comparison of oceanic turbulence and copepod swimming

Abstract

There is a large number of phenomena which determine zooplankton motion in the upper ocean. This note compares the swimming speeds of a representative sample of zooplankton (Euchaeta rimana, Oithona davisae, and Metridia pacifica) with turbulent velocity fluctuations in the upper ocean. It is shown that nominal swimming speeds of these zooplankton are larger than velocity fluctuations in the seasonal thermocline. Consequently, organism motion can be independent of the local turbulent flow field in this region.