Statistics
For growth rates, main effects were tested using an additive analysis of variance. An additive model was required as there was only one growth rate calculated per combination of factors. The assumption of normality was confirmed using the Shapiro-Wilk test. The assumption of equal variance was confirmed for each factor using the F-test.
For biomass phosphorus concentrations, main effects and interaction were tested using an analysis of variance. The assumption of normality was tested using the Shapiro-Wilk test. Biomass phosphorus concentrations required log-transformation to confirm the assumption of normality. The assumption of equal variance was confirmed using the Bartlett’s test.