Conclusion
By combining the annotation of reads and contigs together with genome reconstruction from metagenomic data, we provide the first genetic and genomic evidence that microorganisms inhabiting the Deception Island volcano possess a variety of adaptive strategies and metabolic processes that are shaped by steep environmental gradients. We observed that hyperthermophilic temperatures (98 oC) preferably select microorganisms with reductive and autotrophic pathways, while communities from fumaroles <80 oC show a high metabolic versatility with both reductive and oxidative pathways, and glaciers harbor communities with metabolic processes especially related to carbon metabolism and heterotrophy. Survival strategies of microorganisms from the hottest fumarole are very specialized in responding to the hyperthermophilic temperatures and oxidative stress, while <80 oC fumaroles and glacier communities possesses a variety of strategies that are capable of responding to fluctuating redox and temperature conditions. We found more complex and negative interactions among the communities from the hottest fumarole (98 oC), which indicate that the strong environmental stressors probably trigger competitive associations among community members. Furthermore, through the reconstruction of MAGs, we were able to clarify a putative novel thermophilic lifestyle for a Woesearchaeia member and a marine lifestyle for a Ca.Nitrosocaldus lineage. Our work represents, as far as we know, the first study to reveal through shotgun metagenomics the response of microbial functional diversity to the extreme temperature gradient (0 to 98oC) of an Antarctic volcano. Furthermore, our study was one of the first to recover MAGs from these ecosystems and it provides new insights regarding the metabolic and survival capabilities of different extremophiles inhabiting the Antarctic volcanoes.