Phenotypic and ecological diversity of freshwater coccoid cyanobacteria from maritime Antarctica and islands of NW Weddell Sea. I. Synechococcales.

The review of freshwater natural populations of coccoid cyanobacteria from the ecosystems of the coastal Antarctica in the vicinity of Antarctic Peninsula is presented in two consequent articles. The natural cyanobacterial populations were studied from deglaciated regions with aquatic and terrestrial habitats, mainly from the islands Nelson and King George (South Shetland Islands) and from the northern deglaciated part of the James Ross Island (NW part of the Weddell Sea). Majority of identified morphospecies was distinctly ecologically restricted and their cultivation was not successful; the molecular evaluation was therefore not possible. All morphotypes appeared also in small quantities, and only few morphospecies created locally more intense populations. However, the knowledge of phenotype variation is important for the classification of Antarctic cyanobacterial diversity. This first article contains 11 taxa (morphospecies) from 9 genera from the simple phylogenetic clade, classified recently in the order Synechococcales (the second part will contain species from more complicated unicellular cyanobacterial orders). Our results were compared with literary data, but several populations occurred only rarely in atypical stages and their taxonomic classification was difficult. The modern cyanobacterial system (Hoffmann et al. 2005, Komárek et al. 2013) is used for the classification