Figure 2rRNA gene clone library coverage based on Good’s C estimator of the unicellular eukaryotes (Euk) and Cyanobacteria (Cya) from Lake Karla, Greece. O/P = ratio of observed-to-predicted number of phylotypes.Figure 3(a) Phylogenetic tree selleck bio of relationships of 18S rDNA (ca. 1800bp) of the representative unique (grouped on ��98% similarity) eukaryotic clones (in bold) of the taxa Fungi, Choanoflagellata, Mesomycetozoea, Katablepharidophyta, and Cryptophyta, …Figure 4Phylogenetic tree of relationships of 18S rDNA (ca. 1600bp) of the representative unique (grouped on ��98% similarity) eukaryotic clones (in bold) found in the Lake Karla water column, April 2010, based on the neighbour-joining method …

The Cyanobacteria 16S rRNA gene clone library coverage was satisfactory (Figure 2) and showed (Figure 5) that Cyanobacteria were represented by phylotypes related to the Planktothrix group, the Chroococcales, and several algal plastids. Along with these phylotypes, three Verrucomicrobia-like phylotypes were also retrieved, reinforcing the notion that some Verrucomicrobia are associated with Cyanobacteria-dominated waters [41, 42].Figure 5Phylogenetic tree of relationships of 16S rDNA (ca. 660bp) of the representative unique (grouped on ��98% similarity) Cyanobacterial clones (in bold), March 2010, based on the neighbour-joining method as determined by distance Jukes-Cantor …Microscopic analysis (Figure 6) of phytoplankton gave a slightly different picture of the phytoplankton dominance. In March 2010, the diatom Cyclotella sp. dominated followed by Prymnesium parvum (Haptophyta), Planktothrix cf.

AV-951 agardhii (Cyanobacteria), Euglena sp. (Euglenophyta) and Anabaena sp. (Cyanobacteria) and from Alveolata Pfiesteria cf. piscicida (the latter consisted 0.4% of the high 46.5mgL?1 total biomass and for this it is not included in Figure 6). Most of these microorganisms have been also found in April 2010 but in lower biomass. Nevertheless, the phylotypes of these organisms have been found in the respective clone libraries from both dates.Figure 6Relative biomass of the major taxa (90% dominance) recognized with light microscopy in the Lake Karla water column.The slight discrepancy between the two approaches is expected (e.g., [43]) as PCR-based phylotype abundance is not quantitative but rather shows relative differences and can also be biased towards some groups. On the other hand, microscopic identification of unicellular phytoplankton can be problematic for some organisms, especially for these with complex/uncertain life cycles (e.g., [3, 25]).