image: Cyanobacterial markers in deep core samples revealed by a Life Detector Chip immunoassay. view more
Credit: PNAS
Researchers report detection of viable cyanobacteria in a deep borehole, far from the reach of sunlight for photosynthesis. Cyanobacteria inhabit most environments, but their ecological range is thought to be limited to environments with at least some sunlight to facilitate photosynthesis. Fernando Puente-Sánchez and colleagues report evidence of viable cyanobacteria in a 613-meter-deep borehole from the Iberian Pyrite Belt in Spain, an analog for geochemical conditions on Mars. The authors characterized the cyanobacteria using microscopy, metagenomics analysis, and immunoassays. Because hydrogen abundance was negatively correlated with cyanobacterial abundance and because pathways for hydrogen use are present in the metagenomic data, the authors suggest that the cyanobacteria use hydrogen as an electron donor and, potentially, iron, manganese, nitric oxide, or other products of organic matter as electron acceptors. Several characteristics of cyanobacteria that developed in other environments, such as adaption to living within rocks and under severe nutritional and environmental stresses, may have facilitated life in the deep subsurface. According to the authors, cyanobacteria may serve as important primary producers in the deep subsurface. The findings suggest a need for the re-evaluation of potential terrestrial and extraterrestrial cyanobacterial niches.
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Article #18-08176: "Viable cyanobacteria in the deep continental subsurface," by Fernando Puente-Sánchez et al.
MEDIA CONTACTS: Fernando Puente-Sánchez, Centro Nacional de Biotecnología, Madrid, SPAIN; e-mail: fpuente@cnb.csic.es; Victor Parro Garcia, Centro de Astrobiología, Madrid, SPAIN; e-mail: parrogv@inta.es
Journal
Proceedings of the National Academy of Sciences