Search results for " maximum"

showing 3 items of 303 documents

A stochastic reaction-diffusion-taxis model for two picophytoplankton populations

2012

In this work, the stationary distributions of two populations of picophytoplankton, i.e. picoeukaryotes and Prochlorococcus, are studied. This two groups account on average for 60% of the total chlorophyll a (chl a) and divinil chlorophyll a (divinil chl a) concentration in Mediterranean Sea. The interaction of these populations with the environment occurs through two factors that limit the growth of the aquatic microorganisms: light intensity and nutrient, i.e. phosphorus. The dynamics of the two picophytoplanktonic groups, distributed at different depth along a water column (one-dimensional spatial domain), is analyzed starting from a deterministic reaction-diffusion-taxis model. This con…

marine ecosystemspatial ecologyspatial ecology; marine ecosystems; phytoplankton dynamics; deep chlorophyll maximum; random processes; stochastic differential equationsrandom processedeep chlorophyll maximumphytoplankton dynamicstochastic differential equationsSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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A stochastic reaction-diffusion-taxis model for picophytoplankton dynamics

2011

The dynamics of picophytoplankton communities in marine environment is studied by astochastic reaction-dìffusìon-taxis model, analyzing the time evolution of the biomass concentration along a water column. The model is based on two stochastic differentìal equations, where the random fluctuations of the environmental variables are considered by inserting two multiplicative noise terms. Specifically, the model describes the dynamics of diffusion of picophytoplankton biomass and nutrient concentrations. In the proposed model the marine environment is characterized by poorly mixed waters and picophytoplankton is subject to intraspecific competition for light and nutrients. By numerically solvin…

marine ecosystemSpatial ecologyrandom processeSpatial ecology; marine ecosystems; phytoplankton dynamics; deep chlorophyll maximum; random processes; stochastic differential equationsdeep chlorophyll maximumphytoplankton dynamicstochastic differential equationsSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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Reaction-diffusion-taxis model for spatio-temporal dynamics of five picophytoplankton populations

2014

Recently new models were devised to study spatio-temporal dynamics of phytoplankton populations in view of obtaining more precise predictions of the vertical biomass distributions in marine ecosystems. These studies can be crucial from the point of view of shery. Indeed the abundance of fi sh species is strictly connected with primary production, i.e. phytoplankton biomass, responsible for chlorophyll concentration. In this work a one-dimensional deterministic reaction-di ffusion-taxis model is used to reproduce the spatio-temporal dynamics, along a water column, of five picophytoplankton populations sampled in a real ecosystem. In our analysis, to better reproduce the spatio-temporal behav…

Marine ecosystemStochastic differential equationsSpatial ecologyDeep chlorophyll maximumPhytoplankton dynamicRandom processeSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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