Preservation of underground microbial diversity in ancient subsurface deposits (>6 Ma) of the Rio Tinto basement
Entity
UAM. Departamento de Biología MolecularPublisher
MDPIDate
2021-07-27Citation
10.3390/microorganisms9081592
Microorganisms 9.8 (2021): 1592
ISSN
2076-2607 (online)DOI
10.3390/microorganisms9081592Editor's Version
https://doi.org/10.3390/microorganisms9081592Subjects
Placers; Minerals; Cupriavidus Metallidurans; Biología y Biomedicina / BiologíaRights
© 2021 by the authorsAbstract
The drilling of the Rio Tinto basement has provided evidence of an underground microbial community primarily sustained by the Fe and S metabolism through the biooxidation of
pyrite orebodies. Although the gossan is the microbial activity product, which dates back to the
Oligocene (25 Ma), no molecular evidence of such activity in the past has been reported yet. A Time
of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) molecular analysis of a subsurface sample
in the Peña de Hierro basement has provided novel data of the ancient underground microbial
community. It shows that the microbial remains are preserved in a mineral matrix composed of
laminated Fe-oxysulfates and K- and Na-bearing sulfates alternating with secondary silica. In such
a mineral substrate, the biomolecule traces are found in five different microstructure associations,
(1) <15 micron-sized nodular microstructures composed of POn(2≤n≤4)
−, (2) <30 micron-size micronodules containing fatty acids, acylglycerides, and alkanol chains, (3) <20 micro-sized nodules containing NOn
−
(2≤n≤3) ions, (4) 40-micron size nodules with NH4
+ and traces of peptides,
and (5) >200-micron thick layer with N-bearing adducts, and sphingolipid and/or peptide traces.
It suggests the mineralization of at least five microbial preserved entities with different metabolic capabilities, including: (1) Acidiphilium/Tessaracoccus-like phosphate mineralizers, (2) microbial patches
preserving phosphate-free acylglycerides bacteria, (3) nitrogen oxidizing bacteria (e.g., Acidovorax sp.),
(4) traces of heterotrophic ammonifying bacteria, and (5) sphingolipid bearing bacteria (e.g., Sphingomonadales, and δ-Proteobacteria) and/or mineralized biofilms. The primary biooxidation process
acted as a preservation mechanism to release the inorganic ions that ultimately mineralized the
microbial structures
Files in this item
Google Scholar:Fernández-Remolar, David C.
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Gómez-Ortiz, David
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Malmberg, Per
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Huang, Ting
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Shen, Yan
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Anglés, Angélica
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Amils Pibernat, Ricardo
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