Mathematical model of ecological mechanism on radionuclide spatial heterogeneity in river system water-phytoplankton-zooplankton-bottom sediments

A mathematical model for the mechanism of radionuclide transport through the river system including water-phytoplankton-zooplankton-bottom sediments is suggested. The following two main regimes of the river system functioning are revealed: 1) the system is limited with a biogenic element which corresponds to homogeneous distribution of all the components over the river run; 2) the system is not limited with a biogenic element which means that interrelations between phytoplankton and zooplankton generate oscillations of all the components in the system including those containing radionuclides. Pure biotic interrelations between organisms may cause the longitudinal oscillations (standing waves) in the river system which in its turn may lead to heterogeneous spatial distribution of radionuclides in water and bottom sediments