Modelling rates of random search over the transition from diffusive to ballistic movement of plankton
Authored by Anna Metaxas, Kevin A Sorochan, Wendy C Gentleman
Date Published: 2017
DOI: 10.1093/plankt/fbx034
Sponsors:
National Science and Engineering Research Council of Canada (NSERC)
Platforms:
MATLAB
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
The rate of search for food (i.e. maximum clearance rate), F, of a
plankter is essential to the prediction of encounter rates, and is
dependent on movement. Classic encounter rate models assume diffusive or
ballistic movements, which represent opposing extremes of directional
persistence. From the perspective of the predator, the directional
persistence of prey is determined by the ratio of the persistence length
(i. e. ``run length{''} of a random walker),., and the radius of prey
detection, r. We developed an individual-based model to (i) describe
variation in F due to lambda/r and time, and (ii) evaluate the utility
of published corrections (that take into account the effect of lambda/r
on F) to the classic models. Our results illustrate that classic models
overestimate F when their assumptions of movement are invalid, and
indicate that the effect of time variation in F on food consumption is
most substantial near the middle of the diffusive to ballistic
transition (i. e. lambda/r approximate to 1). At lambda/r << 1,
predators may exploit high clearance rates by ``jumping{''}, provided
that the far-field concentration of prey is sufficiently high. We
recommend a published Michaelis-Menten type correction to the classic
models, and discuss the assumptions and applications of our model
system.
Tags
chemotaxis
diffusion
Random walk
Phytoplankton
zooplankton
Motility
Small-scale turbulence
Encounter rates
Prey detection
Swimming behavior
Encounter rate
Copepod acartia-tonsa
Clearance rate
Plankton feeding
Search efficiency
Diffusive movement
Ballistic movement
Directional
persistence
Motility
patterns
Sagitta-elegans