Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 16, 2018 | Supplemental Material + Published
Journal Article Open

Viable cyanobacteria in the deep continental subsurface


Cyanobacteria are ecologically versatile microorganisms inhabiting most environments, ranging from marine systems to arid deserts. Although they possess several pathways for light-independent energy generation, until now their ecological range appeared to be restricted to environments with at least occasional exposure to sunlight. 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.

Additional Information

© 2018 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). Edited by David M. Karl, University of Hawaii, Honolulu, HI, and approved August 29, 2018 (received for review May 11, 2018) PNAS published ahead of print October 1, 2018 https://doi.org/10.1073/pnas.1808176115 We thank Javier Tamames, Carlos Pedrós-Alió, Ramón Roselló-Mora, Barbara Sherwood-Lollar, and Chris McKay for useful feedback and discussions of the draft manuscript and all the members of the Iberian Pyrite Belt Subsurface Life (IPBSL) team and the personnel of the Museo Minero de Riotinto. This work was supported by the European Research Council Advanced Grant ERC250350-IPBSL, and the Spanish Ministerio de Economía y Competitividad/Fondo Europeo de Desarrollo Regional Grants AYA2011-24803 and ESP2015-69540-R. F.P.-S. is currently funded by the Spanish Ministerio de Economía y Competitividad/Fondo Europeo de Desarrollo Regional Grant CTM2016-80095-C2-1-R. Author contributions: F.P.-S., A.A.-R., K.N.T., R.A., and V.P. designed research; F.P.-S., A.A.-R., M.O., M.G.-V., M.M.-P., Y.B., N.R., L.B., S.A.L., F.T., O.P.-B., K.H.F., and D.H.P. performed research; F.P.-S., A.A.-R., M.O., Y.B., F.T., O.P.-B., and V.P. analyzed data; and F.P.-S. wrote the paper. This article is a PNAS Direct Submission. Data deposition: Raw sequence data and assemblies that support the findings of this study have been deposited in NCBI under the BioProject ID PRJNA476489. MG-RAST results are deposited under project ID mgp83581. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1808176115/-/DCSupplemental. The authors declare no conflict of interest.

Attached Files

Published - 10702.full.pdf

Supplemental Material - pnas.1808176115.sapp.pdf

Supplemental Material - pnas.1808176115.sd01.xlsx

Supplemental Material - pnas.1808176115.sd02.xlsx


Files (5.4 MB)
Name Size Download all
922.6 kB Preview Download
296.3 kB Download
40.7 kB Download
4.1 MB Preview Download

Additional details

August 19, 2023
October 18, 2023