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Updated: Aug 11, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Diffusive transport in Stokeslet flow and its application to plankton ecology
Uffe Høgsbro Thygesen1, Thomas Kiørboe
1Danish Institute for Fisheries Research, Charlottenlund Slot, Jaegersborg Allé 1, 2920, Charlottenlund, Denmark. uht@dfu.min.dk
Abstract:
In this paper we consider the advective/diffusive transport of a solute near a hovering zooplankter. We approximate the fluid flow with that of a Stokeslet, corresponding to the plankter exerting a point force on the water, and assume that the plankter acts as a point source for the transported solute, located at the same point as the force. We find an analytical expression in closed form for the steady-state concentration of the solute. We also discuss the situation where the plankter performs Brownian motion. Finally we apply the results to the courtship of the marine copepod Pseudocalanus elongatus, where the male performs a mating dance below the hovering female. For this situation, our model supports the hypothesis that the mating dance is guided by the plume of a signalling pheromone.
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