Research paperHow do copper contamination pulses shape the regime shifts of phytoplankton-zooplankton dynamics?

- A model with copper pulses of contamination was considered as in real environment.
- Copper pulses may considerably affect the daphnia and algae population dynamics.
- Positive or negative effect conditions and population regime shifts were analyzed.
- Our bifurcation diagram resumed the types of dynamics in copper disturbed ecosystems.

The presence of pollutants in waters, particularly from heavy metals, is of grave concern worldwide due to its cytotoxicity to organisms. Fish and aquatic organisms are very sensitive to the increasing Cu concentrations in water. Therefore, Cu toxicity partly depends on water quality.To address the effects of impulsive copper contamination of the phytoplankton-zooplankton population dynamics, we've built a model that focuses on the interaction between algae and Daphnia with deterministic and stochastic impulse copper.In fact the Results have shown three types of outcomes depending on copper concentration. In low (4.4μgL−1) copper concentration, deterministic and stochastic pulses may promote the persistence of Daphnia and algae populations unlike the absence of pulses. Whereas, in high (28μgL−1) concentration, it accelerates deficiency and toxicity processes, leads to the extinction of all populations and in intermediate concentrations. Deterministic and stochastic pulses may transform population dynamics in complex oscillations.Numerical results show that the system that has been considered has more complex dynamics including bifurcation, period-doubling oscillations and chaos. Depending on minimum copper concentration in the environment, the bifurcation diagram has highlighted the resilience or the regime shifts of the system in occurrence of pulse contamination.