In this paper, a study is carried out to understand the biological and chemical changes down the ocean depth by considering a coupled nonlinear ecosystem (biodiversity) model containing a pollution function. Our research interest is to gain insight into temporal-spatial dynamics of phytoplankton, zooplanktons, fishes and birds in the ocean polluted by chemical substances. We determine the equilibrium points and the analytic solution to the model using Fourier transform method and numerical simulations for the model are carried out under certain conditions. The population of the species is found to be cyclic, oscillatory and show persistence, coexistence and chemotaxis phenomena at some periods during the simulation. The population of the species is global sector stable and the population ratio of the species varies on a spatial scale of 10 meters from the surface of the ocean to the bottom. From simulation results on species population ratio, the species tend to flourish in patches that provide nutrients, abundant oxygen and comfort from pollution effects.