The efficient long-term inhibition of forsterite dissolution by common soil bacteria and fungi at Earth surface conditions

Oelkers, Eric H.; Benning, Liane G.; Lutz, Stefanie; Mavromatis, Vasileios; Pearce, Christopher R.; Plümper, Oliver

doi:10.1016/j.gca.2015.06.004

Cited by 42 publications

(32 citation statements)

References 120 publications

(126 reference statements)

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“…Based on decreases in dissolution rates with time (Figure ), we hypothesize that siderophores affect olivine dissolution rates by limiting the formation of a surface layer of Fe‐oxyhydroxides that shields portions of the mineral surface from contact with solution. This hypothesis is consistent with previous research indicating that the formation of Fe 3+ ‐bearing surface coatings inhibit olivine dissolution (Oelkers et al., ; Saldi, Daval, Morvan, & Knauss, ; Santelli et al., ).…”

Section: Discussionsupporting

confidence: 93%

“…Our model also explicitly assumes Fe limitation. Under different nutrient regimes, the effects of biological activity on mineral dissolution rates could vary substantially from those predicted by this model (e.g., Garcia et al, 2013;Oelkers et al, 2015;Shirokova et al, 2012). Consequently, the model we present is not meant to fully reproduce weathering processes in natural systems but is used instead to explore how the feedback between the production of ligands and the release of a limiting nutrient controls the extent to which mineral dissolution rates are accelerated.…”

Section: Equationmentioning

confidence: 99%

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The kinetics of siderophore‐mediated olivine dissolution

et al. 2019

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Silicate minerals represent an important reservoir of nutrients at Earth's surface and a source of alkalinity that modulates long‐term geochemical cycles. Due to the slow kinetics of primary silicate mineral dissolution and the potential for nutrient immobilization by secondary mineral precipitation, the bioavailability of many silicate‐bound nutrients may be limited by the ability of micro‐organisms to actively scavenge these nutrients via redox alteration and/or organic ligand production. In this study, we use targeted laboratory experiments with olivine and the siderophore deferoxamine B to explore how microbial ligands affect nutrient (Fe) release and the overall rate of mineral dissolution. Our results show that olivine dissolution rates are accelerated in the presence of micromolar concentrations of deferoxamine B. Based on the non‐linear decrease in rates with time and formation of a Fe3+‐ligand complex, we attribute this acceleration in dissolution rates to the removal of an oxidized surface coating that forms during the dissolution of olivine at circum‐neutral pH in the presence of O2 and the absence of organic ligands. While increases in dissolution rates are observed with micromolar concentrations of siderophores, it remains unclear whether such conditions could be realized in natural environments due to the strong physiological control on microbial siderophore production. So, to contextualize our experimental results, we also developed a feedback model, which considers how microbial physiology and ligand‐promoted mineral dissolution kinetics interact to control the extent of biotic enhancement of dissolution rates expected for different environments. The model predicts that physiological feedbacks severely limit the extent to which dissolution rates may be enhanced by microbial activity, though the rate of physical transport modulates this limitation.

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Section: Discussionsupporting

confidence: 93%

Section: Equationmentioning

confidence: 99%

The kinetics of siderophore‐mediated olivine dissolution

et al. 2019

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“…By cell surface reactivity, we are referring, here and throughout this manuscript, to the passive adsorption reactions that occur at the innate reactive sites on cell surfaces. The reactive sites on the cell wall can affect weathering through direct contact with the mineral surface; however, they can also adsorb aqueous dissolution products, changing the saturation state of the solution and preventing the system from approaching equilibrium (Friis et al, ; Harrold, ; Oelkers et al, ; Wightman & Fein, ). Microbial surface reactivity is due to the high concentration of ion adsorption sites, such as carboxyl and phosphate ligands, on the cell surfaces (Borrok, Fein, & Kulpa, ; Gorman‐Lewis, Fein, & Jensen, ; Harrold & Gorman‐Lewis, ; Kelly et al, , ).…”

Section: Introductionmentioning

confidence: 99%

“…Plants have been found to be generally enriched in heavy Mg isotopes compared with their substrates; however, the extent of the fractionation is dependent upon plant species and environmental conditions (Black, Epstein, Rains, Yin, & Casey, 2008;Bolou-Bi, Poszwa, Leyval, & Vigier, 2010;Bolou-Bi, Vigier, Poszwa, Boudot, & Dambrine, 2012;Uhlig, Schuessler, Bouchez, Dixon, & Blanckenburg, 2017). Variable isotope fractionation effects have been attributed to Mg uptake into bacterial cells (Oelkers et al, 2015;Pokharel et al, 2018) and fungi (Fahad, Bolou-Bi, Kohler, Finlay, & Mahmood, 2016;Oelkers et al, 2015;Pokharel et al, 2017Pokharel et al, , 2018, and the extent and mechanisms of fractionation appear to be largely species dependent. However, Mg isotopes have not previously been applied to systematically elucidate the specific effects of biological surface chemistry on chemical weathering.…”

mentioning

confidence: 99%

“…Bacterial cell surface reactivity can have significant direct and indirect effects on mineral dissolution in a weathering system (Friis, Davis, Figueira, Paquette, & Mucci, 2003;Harrold, 2014;Oelkers et al, 2015;Wightman & Fein, 2004). By cell surface reactivity, we are referring, here and throughout this manuscript, to the passive adsorption reactions that occur at the innate reactive sites on cell surfaces.…”

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confidence: 99%

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Magnesium isotope fractionation during microbially enhanced forsterite dissolution

et al. 2019

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Bacillus subtilis endospore‐mediated forsterite dissolution experiments were performed to assess the effects of cell surface reactivity on Mg isotope fractionation during chemical weathering. Endospores present a unique opportunity to study the isolated impact of cell surface reactivity because they exhibit extremely low metabolic activity. In abiotic control assays, 24Mg was preferentially released into solution during forsterite dissolution, producing an isotopically light liquid phase (δ26Mg = −0.39 ± 0.06 to −0.26 ± 0.09‰) relative to the initial mineral composition (δ26Mg = −0.24 ± 0.03‰). The presence of endospores did not have an apparent effect on Mg isotope fractionation associated with the release of Mg from the solid into the aqueous phase. However, the endospore surfaces preferentially adsorbed 24Mg from the dissolution products, which resulted in relatively heavy aqueous Mg isotope compositions. These aqueous Mg isotope compositions increased proportional to the fraction of dissolved Mg that was adsorbed, with the highest measured δ26Mg (−0.08 ± 0.07‰) corresponding to the highest degree of adsorption (~76%). The Mg isotope composition of the adsorbed fraction was correspondingly light, at an average δ26Mg of −0.49‰. Secondary mineral precipitation and Mg adsorption onto secondary minerals had a minimal effect on Mg isotopes at these experimental conditions. Results demonstrate the isolated effects of cell surface reactivity on Mg isotope fractionation separate from other common biological processes, such as metabolism and organic acid production. With further study, Mg isotopes could be used to elucidate the role of the biosphere on Mg cycling in the environment.

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Effects of Synechococcus sp. cyanobacteria inert biomass on olivine dissolution: Implications for the application of enhanced weathering methods

Weber

Martinez

2017

Applied Geochemistry

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The efficient long-term inhibition of forsterite dissolution by common soil bacteria and fungi at Earth surface conditions

Cited by 42 publications

References 120 publications

The kinetics of siderophore‐mediated olivine dissolution

The kinetics of siderophore‐mediated olivine dissolution

Magnesium isotope fractionation during microbially enhanced forsterite dissolution

Effects of Synechococcus sp. cyanobacteria inert biomass on olivine dissolution: Implications for the application of enhanced weathering methods

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