The Study Of Relation Between Nonlinear Character Of Spatio-temporal Distribution Of Phytoplankton And Red Tide

Red tide is one of environmental problems which are regarded recently. Many valuable conclusions are achieved, which are about mechanism of its occurrence, prediction, simulation and toxicology, etc. Essentially, red tide is an ecological phenomenon leaded by bad environment.Phytoplankton is the key study object in this paper. Nonlinear dynamics of phytoplankton's spatio-temporal distribution is studied under applied mathematics. By numerical experiments, the relation between it and red tide is discovered. Under hydraulics of Pearl River Estuary, equilibrium point and concentration of phytoplankton under the whole effect of factors is simulated. In the end of the paper, equilibrium point of phytoplankton can be a key predicted exponent for red tide breaking out is suggested. All these conclusions are the bases of advancing red tide forecast's time and precision.The main works in this paper are as follows:1. The qualitative analysis of phytoplankton ecological model under different factors is carried. And nonlinear characters of phytoplankton are studied;2. The functions of biological factors and chemical factors on ecological actions of phytoplankton are studied by numerical simulation method;3. One-dimension and two-dimension simulations on 3-component ecological model are worked for studying spatio-temporal distribution of phytoplankton and chaos;4. Hydrodynamics of estuary is simulated on the base of two-dimensional shallow water equations.5. By coupling the nutrient model with phytoplankton growth model, nutrient-phytoplankton-zooplankton ecological model is established. Under hydraulics conditions of Pearl River Estuary, the relation of the occurrence of red tide and the rule of ecological actions of phytoplankton, the relation of the spacial development of red tide and that of phytoplankton and the relation between the equilibrium point development and concentration are studied. Equilibrium point of phytoplankton can be a key predicted exponent for red tide breaking out is proved.