Precipitation of low‐temperature dolomite from an anaerobic microbial consortium: the role of methanogenic Archaea

Abstract

Here we report precipitation of dolomite at low temperature (30 degrees C) mediated by a mixed anaerobic microbial consortium composed of dissimilatory iron-reducing bacteria (DIRB), fermenters, and methanogens. Initial solution geochemistry is controlled by DIRB, but after 90 days shifts to a system dominated by methanogens. In live experiments conditions are initially saturated with respect to dolomite (Omega(dol) = 19.40) and increase by two orders of magnitude (Omega(dol) = 2 330.77) only after the onset of methanogenesis, as judged by the increasing [CH(4)] and the detection of methanogenic micro-organisms. We identify ordered dolomite in live microcosms after 90 days via powder X-ray diffraction, while sterile controls precipitate only calcite. Scanning electron microscopy and transmitted electron microscopy demonstrate that the precipitated dolomite is closely associated with cell walls and putative extra-cellular polysaccharides. Headspace gas measurements and denaturing gradient gel electrophoresis confirm the presence of both autotrophic and acetoclastic methanogens and exclude the presence of DIRB and sulfate-reducing bacteria after dolomite begins forming. Furthermore, the absence of dolomite in the controls and prior to methanogenesis confirm that methanogenic Archaea are necessary for the low-temperature precipitation of dolomite under the experimental conditions tested.

Geochemical Implications of CO2 Leakage Associated with Geologic Storage: A Review

“…However, given the potential for 1) CO 2 to increase the thermodynamic favorability of carbonate precipitation via enhanced CO 2 -induced weathering of soil and aquifer minerals; and 2) the current literature on microbially mediated nucleation of carbonates, the authors of this report believe the consideration of mineral trapping of CO 2 in near surface environments (as a consequence of a CO 2 leak) is warranted (Kenward et al 2009;De Choudens-Sánchez and González 2009;Dean et al 2007;Power et al 2011;Vasconcelos and McKenzie 1997;Roberts et al 2004;Douglas and Beveridge 1998;Dong 2010;Ferris et al 2004;Tobler et al 2011;Mitchell and Ferris 2005).…”

Surface chemistry allows for abiotic precipitation of dolomite at low temperature

“…Microbial dolomite has been produced in the presence of several different metabolic pathways including sulfate reduction, methanogenesis, methanotrophy, sulfide oxidation, and aerobic respiration (12)(13)(14)(15)(16), which may drive precipitation through the supersaturation of solutions with respect to dolomite. Recent work, however, has focused on the role of microbial cells and exopolymeric substances (EPS) as surfaces for dolomite nucleation (17).…”

“…Kinetic inhibition is attributed to lack of solution supersaturation (3), sulfate inhibition (1), cation desolvation (4), and lack of nucleation sites (5). Laboratory precipitation at low temperature has only been successful in producing disordered dolomite: from solutions with high salinity (6); through intermittent (7) or complete dehydration (8); by using organic or inorganic compounds that effectively dewater Mg 2+ ions (9-11); or in the presence of microorganisms, their exudates, or surfaces (12,13).…”

Biomineralization of Carbonate Minerals Induced by the Halophilic <em>Chromohalobacter israelensis</em> under High Salt Concentrations: Implications for Natural Environments

“…Bacteria can serve as a nucleus for carbonate mineral precipitation by adsorbing cations around their EPS [23]. The formation and structures of carbonate crystals induced by methanogenic archaea are controlled by the cell walls and EPS [57]. EPS plays an important role in the complex process of bacterial adhesion to minerals [58].…”