Modelling the impact of diffusion and eutrophic conditions on fungal parasite transmission in poorly-mixed waters.

Fungal parasites are widespread in aquatic ecosystems and play an important role in regulating plankton populations by obligately infecting zooplankton hosts and inducing host mortality. In this study, we develop a transmission dynamics model to describe the interactions among phytoplankton, zooplankton, and fungal parasites within an unstirred chemostat environment. The dynamical properties of the model are investigated, including dissipativity, the existence and stability of steady states, and uniform persistence under suitable conditions on the principal eigenvalues and the basic reproduction number. Numerical simulations reveal that high diffusion rates inhibit the long-term coexistence of species. Additionally, our findings indicate that eutrophic conditions can enhance fungal parasite transmission and induce population fluctuations.