An object-oriented model for the prediction of turbulence effects on plankton
Authored by P Mariani, V Botte, MR d'Alcala
Date Published: 2005
DOI: 10.1016/j.dsr2.2005.01.007
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Platforms:
C++
Model Documentation:
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Abstract
In this work, we propose an object-oriented individual based model for
the analysis of the effects of turbulence on the interactions and the
behaviour of planktonic organisms at microscopic scales. We model
homogeneous isotropic turbulence by adopting a kinematic simulation of
the flow, where the velocity field is prescribed as a combination of a
large number of unsteady random Fourier modes. As for the biotic
component we use special contact classes to build a ``memory{''} of an
individual particle, allowing the storage of frequency, duration and
identity of each interaction experienced by the individuals throughout
the whole time span of the simulation. This, in turn, allows classifying
the different interactions. We tested our model on the classical problem
of the encounter rate between a consumer and a food particle. The model
reproduces well the results of analytical bulk models or of previous
numerical simulations, which demonstrated the enhancement of contact
numbers due to the turbulent flow especially for slow moving or
ambushing consumers. The results also highlight that a critical
parameter in the encounter is the duration of the contacts. This
suggests that the evident decrease in clearance rate of grazers in
experimental setups in the high turbulence range may be significantly
affected by the decrease of the encounter duration and its impact on
detection, capturing and handling the prey. As a matter of fact, the
encounter duration sets a typical scale dependent on the swimming speed, the typical scale of turbulence, and the encounter radius, beyond which
the enhancement of useful encounter rates becomes negligible. (c) 2005
Elsevier Ltd. All rights reserved.
Tags
zooplankton
Particles
Small-scale turbulence
Encounter rates
Contact rates
Copepods
Larval fish
Homogeneous isotropic turbulence
Numerical-simulation
Feeding currents