Which factors are shaping the microbial diversity in the inland high-altitude biotopes of the Western Sør Rondane Mountains (Eastern Antarctica, ACBR6)?

The scarce ice-free terrestrial areas of Antarctica are among the most extreme environments on Earth and are therefore dominated by microorganisms. The BelSPO project BELDIVA (2009-2912) investigated soil and biological crusts’ microbiomes in the vicinity of the Princess Elisabeth Station using amplicon sequencing of the SSU rRNA gene of pro- and eukaryotes and revealed that bedrock type and microhabitat conditions were shaping the community composition and that there were differences in the microbiome-environment relations in comparison to the McMurdo Dry Valleys. In addition, a pilot study of pufM (light harvesting) and RuBisCO (carbon fixation) genes suggested an important role of as yet unknown groups of prokaryotes in the primary production of these ecosystems A more comprehensive study was recently performed during the project MICROBIAN (2016-2021) where samples were collected from a wider range of bedrock types and nunataks/ridges, and remote sensing and drone observation techniques were tested to map physical habitat characteristics and the presence/extent of microbial crust communities in ice-free areas. Indeed, slope and aspect information at different scales are expected to provide useful information to explain the differences in biodiversity at the sampling sites. Based on 142 samples from granite, marble, gneiss and moraine, preliminary results suggest that pH and bedrock type were the most important structuring factors for both Bacteria and Eukaryotes in these ice-free regions.