A 3D Individual-Based Model to Study Effects of Chemotaxis, Competition and Diffusion on the Motile-Phytoplankton Aggregation

Authored by Ilhem Bouderbala, Saadi Nadjia El, Alassane Bah, Pierre Auger

Date Published: 2018

DOI: 10.1007/s10441-018-9318-y

Sponsors: No sponsors listed

Platforms: GAMA

Model Documentation: ODD Pseudocode Mathematical description

Model Code URLs: Model code not found

Abstract

In this paper, we develop a 3D-individual-based model (IBM) to understand effect of various small-scale mechanisms in phytoplankton cells, on the cellular aggregation process. These mechanisms are: spatial interactions between cells due to their chemosensory abilities (chemotaxis), a molecular diffusion and a demographical process. The latter is considered as a branching process with a density-dependent death rate to take into account the local competition on resources. We implement the IBM and simulate various scenarios under real parameter values for phytoplankton cells. To quantify the effects of the different processes quoted above on the spatial and temporal distribution of phytoplankton, we used two spatial statistics: the Clark-Evans index and the group belonging percentage. Our simulation study highlights the role of the branching process with a weak-to-medium competition in reinforcing the aggregating structure that forms from attraction mechanisms (under suitable conditions for diffusion and attraction forces), and shows by contrast that aggregations cannot form when competition is high.
Tags
Individual-based model Simulation Evolution behavior population Protocol Equations Vertical-distribution Particles Nonlocal model Phytoplankton aggregation Density-dependent mortality model Chemosensory ability Nearest-neighbor index Group belonging percentage Mixed water columns Coagulation