Effect of microplastic addition on protist abundance
Overall, across trial 1, MP addition had an overall marginally
significant effect on protist abundance (repeated measures ANOVA
F2,27=0.24, P<0.0540). In addition, protist
abundance varied significantly over the course of the trial
(F6,22=1.50, P<0.0013) (Figure 3A). The
treatment with the highest concentration of MPs tended to have the
smallest number of protists after day 6 since the onset of the trial. In
trial 2, there was no overall difference between the two MP addition
treatments throughout the course of the trial
(F1,18=0.081, P<0.2433) (Figure 3B). However,
time had a significant effect on abundance as demonstrated by the
significant decline in abundance after day 10
(F8,11=59.36, P<0.0001) (Figure 3B).