Run 001 starts with spatially uniform populations so that advection and diffusion do not play any role. There is no zooplankton (Z) throughout the run. We choose the β value to larger than the threshold value beyond which the final Ps value differs from its maximum capacity value (K) (see Rhodes *et al*. 2008).

Fig. 1 shows different time series depending on the initial values for susceptible phytoplankton (Ps) and viruses (V). Notice that the final values do not seem to depend on the initial conditions but the maximum values and the timing are.

Fig. 2 shows the maximum Ps, the timing of that maximum and the final value of Ps for different initial values of Ps and V. We see that

- The maximum value of Ps is lower for moderate values of initial Ps (without the case of no viruses)
- The larger the initial Ps value, the shorter it takes to reach the maximum (consistent with Fig. 1)
- The oddity that
**the larger the initial V value, the faster it takes to reach the maximum Ps value**(with the largest jump occurring between the case where there is no virus and a case where there is a small virus population) - Except in the cases where there is no initial V or Ps, the final Ps value is independent on initial conditions.
- Overall, we notice how different the phytoplankton-virus system behaves compared to the phytoplankton-zooplankton system (see
*11.05.2012: Reproducing Fig. 1 of Richards and Brentnall (2006)*).

To produce Fig. 2, `manyruns_1.py` in `RESEARCH/MODELISATION/marine_viruses/current_version/runs/run_001` has been used and it was plotted with `plot_Psmax_Psfinal_Psmax_timing_Psconv.py` in `RESEARCH/MODELISATION/marine_viruses/current_version/runs/run_001/analysis/manyruns_1`

*Francois*

*Thanks for pointing me to the plots. The max Ps appears to be ~ twice the equilibrium value for a large range of initial condition, which is interesting. But I presume this result is due to the fact you are setting Pi to zero - is that correct? What does it look like if you start with Pi at its equilibrium value? Changes to V0, for instance, can then be thought of as displacements away from equilibrium.*

*Kelvin*