The estimation of the Peruvian current ecosystem by a mathematical model of biosphere

A spatial mathematical model of biosphere (MMB) proposed by the author in an earlier paper is used to describe the hierarchical structure of energy flows in the Peruvian current ecosystem (PCE). The trophic pyramid of the ecosystem includes phyto- and bacterioplankton, non-predatory and predatory zooplankton, three age stages of anchovy (larvae, young, commercial), predatory fishes, and birds. The state of the ecosystems in specific aquatoriums is determined by dissolved matter, detritus, nutrient salts, dissolved oxygen, temperature, and light intensity. The model incorporates spatial and time inhomogeneities in distribution of temperature and current directions. Variations in the biomass of living components of PCE are described by a system of balance equations with assigned initial and boundary conditions. Drifting of non-active components in the current, vertical migrations of fishes and birds were taken into account. The PCE state is estimated with the survivability function. del can be employed both to obtain dynamic characteristics of the PCE and to consider various hypothetic situations that are likely to arise should the conditions in the environment be violated. The examples of such use of the model are given. A dependence of the survivability function is studied with the variations of initial and boundary conditions in the water temperature, illumination, dissolved oxygen, nutrient and vertical water flux. In partial conclusions it is shown that the variations in the water temperature within the limits of ±5 K and the change in vertical advection from 3 · 10−4 to 10−1 cm/s are safe for the PCE functioning.