Имитационное моделирование роста биомассы фитопланктона в Куйбышевском водохранилище

Abstract

A one-dimensional numerical model of the temporal variability of vertical distribution of phytoplankton biomass in the dam reach of the Kuibyshev reservoir was developed on the basis of the known representations of the development of populations of plankton. The model is based on physical processes in which the specific growth rate of phytoplankton is limited by the parameters of mineral phosphorus, water temperature, illumination, hydrodynamics, death and algal consumption by zooplankton. As a result of field hydrochemical and hydrobiological observations carried out in spring and summer 2012 original information concerning adaptation and evaluation of the adequacy of the model to the specific conditions of the Kuibyshev reservoir was obtained. The mechanism of quasi-periodic spikes in the phytoplankton biomass as the result of seasonal changes in environmental factors was reveald in the process of analyzing of the field observations and numerical experiments data. The paper presents a model calculation of phytoplankton in the Kuibyshev reservoir in case of twofold reduction of phosphorus discharge in the Volga basin. The calculation of this scenario shows that the expected response of phytoplankton is sensitive enough to lead to reduction of the biomass and improvement of the trophic status of the Volga reservoirs. Verification of the simulation results showed satisfactory correlation with the data of field observations; this enables to use the developed model for diagnostic and prognostic purposes.