Zelené mikrořasy v polárních jezerech: diverzita, biogeografie a porovnání metodiky

Šamšulová, Tereza

In polar regions, green microalgae (Chlorophyta) are an important group of primary producers. However, little attention has been paid to them in comparison with other primary producers such as diatoms and cyanobacteria. The aim of this thesis was to describe the diversity of Chlorophyta in Arctic and Antarctic lakes, and to gain new insights into their taxonomic composition and biogeographic patterns. Microbial mat samples were collected from the littoral zones of 137 Arctic and Antarctic lakes from various regions (Svalbard, North Greenland, South Greenland, Antarctic Peninsula, and Continental Antarctica) during expeditions performed between 1993 and 2018. We combined Sanger sequencing of isolated strains and amplicon sequencing of environmental samples. The 18S rDNA and ITS2 rDNA regions were analysed using both molecular methods. In total, 65 laboratory cultures were established from Svalbard and Antarctic Peninsula samples. Sanger sequencing of strains revealed 15 taxa belonging to classes Chlorophyceae and Trebouxiophyceae. The most abundant were for instance Chlorella spp. and Micractinium spp. Amplicon sequencing of 18S rDNA yielded 202 OTUs in total, of which 61.4% of OTUs were present in both polar regions. The use of ITS2 rDNA revealed 1,104 OTUs in total, with 53.2% being present in...

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