2.4.
Statistical
analysis
In the screening assays, the main analysis compared the percentage
of cleared area in the macrophyte treatments with that in
the
controls using three-way (Exp. I) and two-way (Exp. II) repeated
measures
ANOVA. This approach was also used for Exp. III to compare
the algal cell density in the macrophyte treatments with the
controls.
All data were tested for normality and homoscedasticity
and assumptions were checked using the procedures outlined
by
Logan (2010). Data recorded as percentages (% of microalgae
cleared
in Exp. I and II and algal cell density in Exp. III) were arcsine
square
root-transformed. An -value of 0.05 was used as the criterion
for significance in all comparisons. When interactions were
significant,
the main effects could not be interpreted (Logan, 2010).
In
these cases, an ANOVA was used to examine the main effect of
time.
Tukey’s HSD tests (P < 0.05) were applied to examine significant
differences between treatments at different days. All analyses
were
performed using the R statistical programme ver. 2.10.1 (R
Development
Core Team, 2009).