Diversity and ecological role of cyanobacterial benthic microbial mats in five lakes, Lützow-Holm Bay, East Antarctica

Cyanobacteria in bottom benthic mats of five lakes in Lützow-Holm Bay, East Antarctica, were investigated by a multi-facet approach. Morphological (cell biovolume - three groups of cyanobacteria were determined according to their cell morphology: unicellular, filamentous, and heterocystous cyanobacteria) and molecular methods (NGS amplicon sequencing of cyanobacterial 16S rRNA) were combined with a characterization of their ecological role (nitrogenase activity). Five samples were collected from five lakes (Bosatsu-ike, Hotoke-ike, Nyorai-ike, Naga-ike, Skallen-ike), spanning a range of different ecological environments in the deglaciated areas of Skarvnes and Skallen. We evaluated the influence of lake characteristics on the cyanobacterial benthic mats’ diversity and ecophysiological activity. In addition to cyanobacteria, eukaryotic microalgae (diatoms, coccoid, filamentous algae – Chlorophyta and Charophyta) were also distinguished. This research is supported by JARE-60 (Japanese Antarctic Research Expedition) 2018/19 and contributes to the long term monitoring of Antarctic lakes.