FIGURE 5.

Variability in the read numbers of the three target microalgal species namely the two Pseudo-nitzschia species that were assigned as P. cuspidata and P. australis, but which were in fact P. delicatissima and P. seriata (A–D) and Prymnesium parvum (E,F) across the different treatments (see Figure 1 for treatment abbreviations). Within each treatment, the reads of each species were compared between the two sequencing methods Illumina MiSeq and Ion Torrent and between filtered and unfiltered marine plankton samples. For the non-prefiltered seawater samples, increasing relative abundances of reads for the target organisms is evident as their concentration is increased in the original sample for every organism except P. australis. A similar pattern is not observed in prefiltered seawater samples. Low levels of cross contamination between the target species (P. perurans an L. salmonis reads in algal samples) is also observed.