TY - JOUR
T1 - Microbially mediated aluminosilicate formation in acidic anaerobic environments
T2 - A cell-scale chemical perspective
AU - Sánchez-España, J.
AU - Wang, K.
AU - Falagán, C.
AU - Yusta, I.
AU - Burgos, W. D.
N1 - Funding Information:
Field work and instrumentation for this study was funded by the Spanish Geological Survey through HERCO2 project (Ref. 2307) and by the Spanish Ministry of Economy (State Secretary of Research, Development and Innovation) through research projects CGL2009-09070 and CGL2016-74984-R. Analytical costs of electron microscopy were funded by the Pennsylvania State University (PSIEE, Department of Civil and Environmental Engineering, and Materials
Funding Information:
Field work and instrumentation for this study was funded by the Spanish Geological Survey through HERCO2 project (Ref. 2307) and by the Spanish Ministry of Economy (State Secretary of Research, Development and Innovation) through research projects CGL2009-09070 and CGL2016-74984-R. Analytical costs of electron microscopy were funded by the Pennsylvania State University (PSIEE, Department of Civil and Environmental Engineering, and Materials Research Institute) and the American Council for International Exchange of Scholars (CIES, US Department of State) through a Fulbright visiting scholar fellowship (grant number PRX14/00087). We thank Jennifer Gray (Materials Characterization Laboratory, Materials Research Institute) for providing assistance during STEM mapping and EELS analyses at PSU. The manuscript benefitted from discussions with Dr. Virginia Souza-Egipsy Sánchez (IEM-CSIC) and from insightful comments by three anonymous reviewers on a previous version.
Funding Information:
Research Institute) and the American Council for International Exchange of Scholars (CIES, US Department of State) through a Fulbright visiting scholar fellowship (grant number PRX14/00087). We thank Jennifer Gray (Materials Characterization Laboratory, Materials Research Institute) for providing assistance during STEM mapping and EELS analyses at PSU. The manuscript benefitted from discussions with Dr. Virginia Souza-Egipsy Sánchez (IEM-CSIC) and from insightful comments by three anonymous reviewers on a previous version.
PY - 2018/1
Y1 - 2018/1
N2 - Through the use of scanning transmission electron microscopy (STEM) combined with other complementary techniques (SEM, cryo-TEM, HRTEM, and EELS), we have studied the interaction of microorganisms inhabiting deep anoxic waters of acidic pit lakes with dissolved aluminum, silica, sulfate, and ferrous iron. These elements were close to saturation (Al, SiO2) or present at very high concentrations (0.12 m Fe(II), 0.12–0.22 m SO4 2−) in the studied systems. The anaerobic conditions of these environments allowed investigation of geomicrobial interactions that are difficult to see in oxidized, Fe(III)-rich environments. Detailed chemical maps and through-cell line scans suggest both extra- and intracellular accumulation of Al, Si, S, and Fe(II) in rod-like cells and other structures (e.g., spherical particles and bacteriomorphs) of probable microbial origin. The bacterial rods showed external nanometric coatings of adsorbed Fe(II) and Al on the cell surface and cell interiors with significant presence of Al, Si, and S. These microbial cells coexist with spherical particles showing similar configuration (Fe(II) external coatings and [Al, Si, S]-rich cores). The Al:Si and Al:S ratios and the good Al–Si correlation in the cell interiors suggest the concurrent formation of two amorphous phases, namely a proto-aluminosilicate with imogolite-like composition and proto-hydrobasaluminite. In both cases, the mineralization appears to comprise two stages: a first stage of aluminosilicate and Al-hydroxysulfate precipitation within the cell or around cellular exudates, and a second stage of SO4 2− and Fe(II) adsorption on surface sites existing on the mineral phases in the case of (SO4 2−) or on presumed organic molecules [in the case of Fe(II)]. These microbially related solids could have been formed by permineralization and mineral replacement of senescent microbial cells. However, these features could also denote biomineralization by active bacterial cells as a detoxification mechanism, a possibility which should be further explored. We discuss the significance of the observed Al/microbe and Si/microbe interactions and the implications for clay mineral formation at low pH.
AB - Through the use of scanning transmission electron microscopy (STEM) combined with other complementary techniques (SEM, cryo-TEM, HRTEM, and EELS), we have studied the interaction of microorganisms inhabiting deep anoxic waters of acidic pit lakes with dissolved aluminum, silica, sulfate, and ferrous iron. These elements were close to saturation (Al, SiO2) or present at very high concentrations (0.12 m Fe(II), 0.12–0.22 m SO4 2−) in the studied systems. The anaerobic conditions of these environments allowed investigation of geomicrobial interactions that are difficult to see in oxidized, Fe(III)-rich environments. Detailed chemical maps and through-cell line scans suggest both extra- and intracellular accumulation of Al, Si, S, and Fe(II) in rod-like cells and other structures (e.g., spherical particles and bacteriomorphs) of probable microbial origin. The bacterial rods showed external nanometric coatings of adsorbed Fe(II) and Al on the cell surface and cell interiors with significant presence of Al, Si, and S. These microbial cells coexist with spherical particles showing similar configuration (Fe(II) external coatings and [Al, Si, S]-rich cores). The Al:Si and Al:S ratios and the good Al–Si correlation in the cell interiors suggest the concurrent formation of two amorphous phases, namely a proto-aluminosilicate with imogolite-like composition and proto-hydrobasaluminite. In both cases, the mineralization appears to comprise two stages: a first stage of aluminosilicate and Al-hydroxysulfate precipitation within the cell or around cellular exudates, and a second stage of SO4 2− and Fe(II) adsorption on surface sites existing on the mineral phases in the case of (SO4 2−) or on presumed organic molecules [in the case of Fe(II)]. These microbially related solids could have been formed by permineralization and mineral replacement of senescent microbial cells. However, these features could also denote biomineralization by active bacterial cells as a detoxification mechanism, a possibility which should be further explored. We discuss the significance of the observed Al/microbe and Si/microbe interactions and the implications for clay mineral formation at low pH.
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U2 - 10.1111/gbi.12269
DO - 10.1111/gbi.12269
M3 - Article
C2 - 29322690
AN - SCOPUS:85040375336
VL - 16
SP - 88
EP - 103
JO - Geobiology
JF - Geobiology
SN - 1472-4677
IS - 1
ER -