Langmuir circulations and plankton patchiness

A computer simulation model of oceanic Langmuir circulations illustrates the role of these vortical water movements as physical forcing mechanisms affecting the horizontal and vertical distributions of planktonic organisms. The diel migration of omnivorous and herbivorous zooplankton (approximately by literature values for the swimming speeds of Meganyctiphanes norvegica and Calanus finmarchicus, respectively) and the sinking of phytoplankton interact with the Langmuir cells, resulting in a spatially heterogeneous community. The patchy distributions, in turn, affect the prey—predator interactions in this simple food web. Situations involving threshold and non-threshold feeding strategies as well as constant and changing circulations are investigated. The simulations are restricted to twilight and nocturnal events.