Figure 1.
The ratio between the total number of reads and the number of phytoplankton reads (A) and rarefaction curves of the next-generation sequencing data (from all 259 samples) (B).
The lines depict different ratios (phytoplankton reads∶total number of reads) and the points represent the samples.
Table 1.
Summary statistics of sequencing data including coordinates and classification of systems.
Figure 2.
Phylogenetic tree (based on SILVA106 reference tree) showing representative sequences from all phytoplankton-related OTUs.
Inner ring indicates the similarity of sequences to the nt/nr database (NCBI) as determined by BLAST search. Outer ring (bars) indicates the number of reads assigned to each node when using the resampled dataset (100 reads); note that nodes where all reads were removed by resampling are still given. Colored branches indicate group assignments from Bayesian classifier against a phytoplankton database.
Figure 3.
Ordination plot showing phytoplankton community composition among lakes of different trophic status (oligotrophic, mesotrophic, eutrophic and dystrophic).
Stress value was 0.20. Permutational ANOVA confirmed visual inspection of significant differences in community composition between lakes of different status (p<0.001; R2 = 0.254).
Table 2.
Results of permutational MANOVA comparing the phytoplankton communities among systems with different trophic status.
Figure 4.
Boxplot showing ratios in taxonomic composition (at phylum level) as revealed by next generation sequencing (NGS) vs. microscopy.
Plots show the ratio between relative reads numbers and biovolumes (as determined by microscopy) for each phylum. (AM) Alinen Mustajarvi, (ER) Lake Erken, and (RI) Rimov Reservoir. A ratio above zero indicates that a specific phylum is preferentially detected by NGS whereas a ratio below zero indicates an over representation in the biovolume data relative to NGS. The part of the plot indicated in grey represents the area where the ratio is the result of that a phylum was only detected by either method.
Table 3.
Results from Procrustes superimposition and Mantel's test to test for correspondence among methods.
Figure 5.
Heatmap showing temporal dynamics of phytoplankton taxa in dystrophic Lake Alinen Mustajärvi (A), mesotrophic Lake Erken (B), and mesotrophic reservoir Rimov (C) as revealed by next generation sequencing.
Colors indicate the abundance of each taxon at each time point in relation to its maximum abundance in the respective time-series.