Comparative genomics of Central Arctic Ocean microbiota for observation of Alternative Carbon Fixation Pathways

The Central Arctic Ocean is a repository of rich and diverse biota, whose major portion is one of the most important drivers of global biogeochemical cycles, including carbon cycling. In this study, the functional potential of the microbiota to fix carbon with alternative carbon fixation pathways were investigated along with their chemolithotrophic characteristics. Samples from two expeditions MOSAiC & SAS-Oden (2019-2021) resulted in metagenomic data consisting of about 1200 mOTUs (metagenomic Operational Taxonomic Units). Kofamscan based annotation explained by KEGG pathways database was analysed to explore prevalence of the alternative Carbon Fixation pathways across different taxa. From the six carbon fixation pathways, three were consolidated for their presence (rTCA, DC-HP, HP-HP). In order to explain the other metabolic processes that these organisms employ to survive, a functional annotation tool for metabolic pathways was used. that Reductive Tricarboxylic acid cycle pathway was found to be most present and observed in 5 out of 6 mOTUs selected from filtering the dataset. The taxa include bacterial phyla Proteobacteria, Actinobacteria, Chloroflexota and Marinisomatota and archaeal phyla Thermoplasmota. However, for the other pathways and less studied organisms less resolution were observed across the dataset for the presence of other pathways. These CFPs found were also supported by oxidation of inorganic compounds with high redox potentials. This study provides a glimpse of the metabolic potential of the Central Arctic Ocean microbiota, shines light on the importance of understanding and unravelling the intricacies of this rich and diverse environment.