Fig 4. Dilution curves show the classical dilution method is insensitive to niche competition.

Apparent growth rates are plotted against the proportion of whole seawater for each bottle in the in silico dilution series after a 24h incubation period when using the classical dilution method and the Z-dilution method respectively. Three cases, each with different microzooplankton grazing pressure conditions (LP: Low pressure, IP: Intermediate pressure and HP: high pressure, as defined in Fig 2) are shown. The estimated mortality rate (m_est) found as the linear regression slope, the baseline mortality rate (m_act) and the percentage error in estimation are shown for each subplot (all rounded to 3 s.f.).