Numerical Study of An NPZOC Model: Integrator Performance, Bloom Dynamics, and Stability Transitions

Abstract

. This study introduces the nutrient–phytoplankton–zooplankton– oxygen–carbon (NPZOC) model, an extended formulation of the classical NPZO sys-tem, to provide a more comprehensive representation of biogeochemical interactions in aquatic ecosystems. Unlike previous studies, the NPZOC model explicitly incorporates carbon dynamics, offering new insights into coupled nutrient–oxygen–carbon processes. The novelty of this work lies in the derivation of explicit stationary (equilibrium) points, which have not been reported before, and in the development of numerical algorithms using fourth-order Runge–Kutta and Yoshida symplectic integrators to simulate system behavior. Using realistic parameterization and initial conditions, we analyze system stability and reveal complex dynamic patterns of the NPZOC model. These results not only extend the theoretical understanding of aquatic ecosystem models but also provide practical tools for investigating carbon–oxygen interactions in marine and freshwater environments.