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.