(Fig. 4). Nevertheless, even for the non-stressed samples, individual species
could not be easily discerned by PCA. In particular, there was considerable
overlap of the C. reinhardtii samples with the clusters of other
adjacent species (Fig. 4a). C. reinhardtii is the only species that has been
analysed over numerous separate experiments and therefore the larger
sample size would likely have exacerbated the variation within the
C. reinhardtii samples, which is almost as great as the variation between
all other species. Thus, due to the similarity of the metabolic fingerprints
from these microalgae species, the experimental-derived variation for
the C. reinhardtii samples may affect the ability to differentiate between
all the species, even when grown under non-stressed conditions.