Cyanobacteria (blue-green algae, Class Cyanophyceae) typically occur in low numbers in Antarctic waters (Marchant et al., 1987a). Chroococcoid cyanobacteria have been found in sea-ice communities (Waterbury et al., 1979; Walker & Marchant, 1989; Mathot et al., 1991; Gradinger & Lenz, 1995), and have been reported in concentrations of up to 140 cells per ml in the water column at an Antarctic coastal site (Walker & Marchant, 1989). Thus, they represent a minor source of carbon for higher trophic levels in Antarctic waters.
There is only a single taxon in this class and as such there is no taxonomic key presented. A link to the factsheet is located above. Images are sourced from Antarctic Marine Protists (eds. Scott & Marchant, 2005).