Effects of toxicity and zooplankton selectivity on plankton dynamics under seasonal patterns of viruses with time delay

Abstract

Intricate functional diversities in marine ecosystems often lead to exhibit a variety of dynamical behaviors, including chaos. To bring order into such chaotic situations, the system develops different mechanisms of self‐adaptability. Our present investigation is based on the study of an eco‐epidemiological model for virally infected toxic phytoplankton and zooplankton system. Both healthy and infected phytoplankton are assumed to be exposed to grazer zooplankton with a varying degree of exposure. An extension is made by introducing the fact that viral replication process in a lysis event is mediated by some time lag. To achieve more realistic and explicit outcomes of the existing phenomena correlated with our model, we consider the force of infection and replication of free viruses as seasonally forced. We find that time delay accounts for recurrent stability switching event in the system. The chaotic behavior is observed in the seasonally forced delayed system, which indicates the emergence of harmful blooms. The main motive is to gain a clear insight into the field of synchronization and stabilization of the irregular behaviors of the system. Our investigations suggest that increased strength of toxic compounds exuded by phytoplankton species may suppress the prevalence of chaotic disorder and drives the system into a zooplankton‐free zone. The intensity of selective grazing of zooplankton changes the state of chaos to order and promotes the disease‐free system.