Viable cyanobacteria in the deep continental subsurface

Abstract

SignificanceCyanobacteria 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.

2038 – When microbes rule the Earth

“…Metagenomic and geochemical evidence point toward the possibility of hydrogen‐based chemolithoautotrophic metabolism by these cyanobacteria that are phylogenetically related to endolithic species (Puente‐Sánchez et al ., ). Thus, we have a situation in which some cyanobacteria do not generate oxygen (Puente‐Sánchez et al ., ) while methanotrophic ‘ Candidatus Methylomirabilis oxyfera’ does generate oxygen (Ettwig et al . ), opening up questions about the evolution of oxygen on Earth, as well as confirming the view that the field of environmental microbiology will be throwing up surprises, that influence diverse disciplines and that have important societal consequences, up to and beyond 2038.…”

“…The marvel of environmental microbiology is that its notions are frequently turned on their head, as exemplified by the discovery of cyanobacteria, generally known for their photosynthetic activity, as the dominant members of a deep, dark sub-surface environment that forms part of the Iberian Pyrite Belt (Puente-Sánchez et al, 2018). Metagenomic and geochemical evidence point toward the possibility of hydrogen-based chemolithoautotrophic metabolism by these cyanobacteria that are phylogenetically related to endolithic species (Puente-Sánchez et al, 2018).…”

“…The marvel of environmental microbiology is that its notions are frequently turned on their head, as exemplified by the discovery of cyanobacteria, generally known for their photosynthetic activity, as the dominant members of a deep, dark sub-surface environment that forms part of the Iberian Pyrite Belt (Puente-Sánchez et al, 2018). Metagenomic and geochemical evidence point toward the possibility of hydrogen-based chemolithoautotrophic metabolism by these cyanobacteria that are phylogenetically related to endolithic species (Puente-Sánchez et al, 2018). Thus, we have a situation in which some cyanobacteria do not generate oxygen (Puente-Sánchez et al, 2018) while methanotrophic 'Candidatus Methylomirabilis oxyfera' does generate oxygen (Ettwig et al 2010), opening up questions about the evolution of oxygen on Earth, as well as confirming the view that the field of environmental microbiology will be throwing up surprises, that influence diverse disciplines and that have important societal consequences, up to and beyond 2038.…”

Widespread methane formation byCyanobacteriain aquatic and terrestrial ecosystems

“…Methane production by Cyanobacteria has been attributed to either demethylation of methylphosphonates (Beversdorf, White, Björkman, Letelier, & Karl, 2010; Gomez-Garcia, Davison, Blain-Hartnung, Grossman, & Bhaya, 2011; Yao, Henny, & Maresca, 2016) or to the association of filamentous Cyanobacteria with methanogenic Archaea , providing the latter with the necessary hydrogen for CH 4 production (Berg, Lindblad, & Svensson, 2014). Cyanobacteria are ubiquitous, found literally in any illuminated environment as well as unexpectedly in some dark subsurface ones as well (Hubalek et al, 2016; Puente-Sánchez et al, 2018). Furthermore, this phylum predominated Earth whilst the environment was still reductive and ca.…”

On the origin of oxygenic photosynthesis and Cyanobacteria

“…Z denotes a core-bound antenna chlorophyll retained in PSII and Type I reaction centres but lost in the anoxygenic Type II reaction centres concomitant with the loss of core antenna and the evolution of a new light harvesting system. cold extreme habitats(Chrismas et al, 2016;Chrismas et al, 2018); underrepresented freshwater genomes(Di Cesare et al, 2018;S anchez-Baracaldo et al, 2019); and genomes from continental subsurfaces(Puente-S anchez et al, 2018).…”