Key to living in the extreme desert soils of eastern Antarctica: a chemolithotrophic lifestyle
Mitchell Peninsula is located at the south of the Windmill Islands, Eastern Antarctica. It is described as a nutrient poor, extreme polar desert and limited knowledge on the microbial diversity of the soils in this area exists. We examined the microbial taxonomic composition and metabolic potential of Mitchell Peninsula soils using 16S metagenomics and shotgun metagenomics. We found the site to be a potential biodiversity hotspot, containing a high abundance of Candidate Phyla WPS2 and AD3. Subsequently, differential binning was used to recover 23 draft genomes, including 3 genomes from WPS-2 and two from AD3. Further analysis of the metagenome revealed a novel Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) gene to be abundant in the bacterial community, despite a lack of evidence for photosynthesis related genes. We believe that unlike many other Antarctic regions, chemolithautrophic carbon fixation via CBB cycle is the dominant carbon fixation pathway, hence this pathway is providing the key to survival is this very dry, hostile environment.