# 03.04.2013: Fourth analysis of run 001. Part 2ΒΆ

Here, we plot the same figures as Figs. 5 to 8 in this note except that there is no viruses. By comparing the two sets of figures, we can see the effect of viruses in the Ps0-Z0 phase space.

Fig. 1 is the same as Fig. 1 of Richards and Brentnall (2006) [shown in this another note].

1. As already deduced, the effect is for low Z0 (Fig. 1).
2. The main difference is that when Z0 is low but Ps0 is high, Ps will not reach a higher maximum value with viruses than without viruses (as illustrated in Figs. 5 and 6 below).
3. Obviously, Pi and V are always zero (Fig.s 2 and 3).
4. No pattern change for Z0 (Fig. 4).

Figure 1: Maximum value of Ps and its timing and the final value of Ps.

Figure 2: Maximum value of Pi and its timing, and the final value of Pi.

Figure 3: Maximum value of V and its timing, and the final value of V.

Figure 4: Maximum value of Z and its timing, and the final value of Z.

Fig. 5 and 6 compare the evolution of the ecosystem starting from the same initial conditions (Ps0=0.4, Z0=0.01, Pi0=0) with or without viruses initially. Conclusion: The viruses are modulating the bloom, making it multi-peaked.

Figure 5: Time series of all quantities. Ps0=0.4 and Z0=0.01, V0=0.

Figure 6: Time series of all quantities. Ps0=0.4 and Z0=0.01, V0=0.25.

Fig. 7 shows the evolution of the system with the initial virus population being much larger than in Fig. 6 (V0=0.8). It shows that however large the initial virus population is, the long-term dynamics stays dominated by the Ps-Z dynamics.

Figure 7: Time series of all quantities. Ps0=0.4 and Z0=0.01, V0=0.8.

To produce Figs. 1 to 4, manyruns_4.py in RESEARCH/MODELISATION/marine_viruses/current_version/runs/run_001 has been used and were plotted with plot_analysis_many_runs_4.py in RESEARCH/MODELISATION/marine_viruses/current_version/runs/run_001/analysis/manyruns_4/. Everything is on the main ipu1 disk.