Research On The Third Trophic Level Eutrophication Model Of Landscape Lake

Landscape lake has been regarded as the important habitat of leisure and entertainment for people all the time.However,recently the eutrophication of landscape lake is becoming more and more serious.The question of how to control and relieve the eutrophication of landscape lake is becoming a research hotspot to resolve immediately.Based on the mechanism of lake eutrophication,the formula of eutrophication is established to describe the relationship of aquatic organism and water quality in the process of physical,chemical and biological variation of the aquatic ecological system.And the eutrophication model is regarded an important tool to prevent and management water eutrophication.Based on the research topic of eutrophication model,Establishment of fish sub model and effect of fish on eutrophication is explored in this paper.In addition,the advice on controlling water eutrophication by fish is proposed in the paper.Firstly,referencing related method of establishing fish sub-model,conservation equation of the fish biomass is established based on constructive metabolism and destructive metabolism of fish.Constructive metabolism refers to fish anabolism by predation.Destructive metabolism included fish basal metabolism,fish feed metabolism and fish mortality.Secondly,based on literature and experiment,value of constants and priori information of parameters are obtained.And the posterior distribution of parameters is calculated by MCMC algorithm in Bayesian theory.In order to improve convergence efficiency of MCMC algorithm,multichain parallel adaptive metropolis algorithm coupled with genetic algorithm is employed to calculate the posterior distribution of parameters based on Matlab in this paper.Thirdly,based on the third eutrophic level eutrophicaiton modle(fish sub-model),the three level eutrophication modle(phytoplankton-zooplankton-fish model)is built by coupling with the two level eutrophication modle(phytoplankton-zooplankton model).And,investigating the dominate fish species and its distribution of the primary in the Ming Li lake of Tianjin University of Technology,this paper selected the crucian and pseudorasbora parva as the representative fish species of the model to simulate and analyze eutrophication of Ming Li lake.According to the results of simualation,the vailidity of established model is verified.Finally,the effect of fish on eutrophication and causes of effect are briefly elaborated.And suggestive measures of controlling eutrophication by breeding fish are proposed.This paper provide theoretical guide to the remediation of eutrophication and fishery management in lake.