Discrete-time dynamical systems of ocean ecosystems and epidemiological models

In this talk, we consider discrete-time models of ocean ecosystems and epidemiological models such as SEIR and SISI. For the ocean ecosystem it was studied the model consisting of nitrogen, phytoplankton and zooplankton and there was constructed the model illustrating the interactions between living organisms such as phytoplankton, zooplankton, mixoplankton, bacteria and non-living components such as dissolved organic and inorganic matters. The epidemic SEIR model representing COVID-19 spread was studied in discrete-time. For the SISI epidemic model it was shown the existence of interior fixed points and studied the limit points of the trajectory.