0000000000993672
AUTHOR
D. Valentiy
MEAN FIELD APPROACH AND ROLE OF THE COLOURED NOISE IN THE DYNAMICS OF THREE INTERACTING SPECIES
We study the effects of the coloured noise on the dynamics of three interacting species, namely two preys and one predator, in a two-dimensional lattice with N sites. The three species are affected by multiplicative time correlated noise, which accounts for the effects of environment on the species evolution. Moreover, the interaction parameter between the two preys is a dichotomous stochastic process, which determines two dynamical regimes corresponding to different biological conditions. Preliminarily, we study the noise effect on the three species dynamics in single site. Then, we use a mean field approach to obtain, in Gaussian approximation, the moment equations for the species densiti…
PICOPHYTOPLANKTON DYNAMICS IN NOISY MARINE ENVIRONMENT
We present a stochastic reaction-diffusion-taxis model to describe the picophytoplankton dynamics along a water column. The model, which is valid for poorly mixed waters, typical of the Mediterranean Sea, considers intraspecific competition of picophytoplankton for light and nutrients. Random fluctuations of environmental variables are taken into account by adding a source of multiplicative noise to the diffusion equation for the picophytoplankton biomass concentration, whose distribution along the water column shows a maximum at a certain depth. After converting our results into chlorophyll a concentrations, we compare theoretical distributions, obtained for different noise intensities, wi…