Científicos españoles encuentran cianobacterias en el subsuelo del suroeste de España

Cyanobacteria were responsible for the origin of oxygenic photosynthesis, and have since come to colonize almost every environment on Earth. Here we show that their ecological range is not limited by the presence of sunlight, but also extends down to the deep terrestrial biosphere. We report the presence of microbial communities dominated by cyanobacteria in the continental subsurface using microscopy, metagenomics, and antibody microarrays. These cyanobacteria were related to surface rock-dwelling lineages known for their high tolerance to environmental and nutritional stress. We discuss how these adaptations allow cyanobacteria to thrive in the dark underground, a lifestyle that might trace back to their nonphotosynthetic ancestors.

Here we present molecular, microscopic, and metagenomic evidence that cyanobacteria predominate in deep subsurface rock samples from the Iberian Pyrite Belt Mars analog (southwestern Spain). Metagenomics showed the potential for a hydrogen-based lithoautotrophic cyanobacterial metabolism. Collectively, our results suggest that they may play an important role as primary producers within the deep-Earth biosphere. Our description of this previously unknown ecological niche for cyanobacteria paves the way for models on their origin and evolution, as well as on their potential presence in current or primitive biospheres in other planetary bodies, and on the extant, primitive, and putative extraterrestrial biospheres.

Distribution of cyanobacteria and other microbial taxa in core samples from the Iberian Pyrite Belt deep subsurface. (A) Relative abundance of different cyanobacterial clades based on 16S rRNA amplicons (bars) and hydrogen concentrations (purple area) across the borehole samples. Hydrogen concentrations are shown relative to the sample with the highest hydrogen concentration. (B) Taxonomic composition of the metagenomic reads from samples 420 and 607.

 

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