Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite

Zhang, Fangfu; Xu, Huifang; Konishi, Hiromi; Shelobolina, Evgenya S.; Roden, Eric E.

doi:10.2138/am.2012.3979

Cited by 152 publications

(141 citation statements)

References 81 publications

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“…In addition, extracellular polymeric substances (EPS) produced by cells, typically contain "excess" negatively charged functional groups [101]. Cations adsorbed to functional groups may become partially dehydrated, allowing for carbonate ions (CO 3 2− ) to react with the otherwise inaccessible cations (Equation (7)) [111][112][113].…”

Section: Bioreactors For Carbon Mineralizationmentioning

confidence: 99%

Strategizing Carbon-Neutral Mines: A Case for Pilot Projects

et al. 2014

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Ultramafic and mafic mine tailings are a valuable feedstock for carbon mineralization that should be used to offset carbon emissions generated by the mining industry. Although passive carbonation is occurring at the abandoned Clinton Creek asbestos mine, and the active Diavik diamond and Mount Keith nickel mines, there remains untapped potential for sequestering CO 2 within these mine wastes. There is the potential to accelerate carbonation to create economically viable, large-scale CO 2 fixation technologies that can operate at near-surface temperature and atmospheric pressure. We review several relevant acceleration strategies including: bioleaching of magnesium silicates; increasing the supply of CO 2 via heterotrophic oxidation of waste organics; and biologically induced carbonate precipitation, as well as enhancing passive carbonation through tailings management practices and use of CO 2 point sources. Scenarios for pilot scale projects are proposed with the aim of moving towards carbon-neutral mines. A financial incentive is necessary to encourage the development of these strategies. We recommend the use of a dynamic real options pricing approach, instead of traditional discounted cash-flow approaches, because it reflects the inherent value in managerial OPEN ACCESS Minerals 2014, 4 400 flexibility to adapt and capitalize on favorable future opportunities in the highly volatile carbon market.

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Section: Bioreactors For Carbon Mineralizationmentioning

confidence: 99%

Strategizing Carbon-Neutral Mines: A Case for Pilot Projects

et al. 2014

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“…Conventional stable and radiogenic isotope systems, trace element geochemistry as well as petrographic approaches (e.g., Tucker, 1983;Aulstead et al, 1988;Last, 1990;Vasconcelos et al, 1995;Budd, 1997;Warren, 2000;Machel, 2004;Zhang et al, 2012b;Mathieu et al, 2013) are generally applied to ancient dolostone studies. However, none of these traditional approaches can provide unambiguous solution to the origin of ancient dolostone.…”

Section: Introductionmentioning

confidence: 99%

Magnesium isotopic compositions of the Mesoproterozoic dolostones: Implications for Mg isotopic systematics of marine carbonates

Huang

Shen

Lang

et al. 2015

Geochimica et Cosmochimica Acta

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“…Although the exact process driving dolomite formation in the CCA has yet to be determined, considering the abundance of sedimentary dolomite in greenhouse epochs 5 and the evidence for an organic driver 4,24,25 , it is reasonable to suggest that dolomite biomineralization is not inhibited by low saturation state. Support for this notion comes from a recent study demonstrating that dolomite can form abiotically in red algae polysaccharide solutions at starting pH of 7.7-7.9 (ref.…”

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Dolomite-rich coralline algae in reefs resist dissolution in acidified conditions

et al. 2012

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Coral reef ecosystems develop best in high-flow environments but their fragile frameworks are also vulnerable to high wave energy. Wave-resistant algal rims, predominantly made up of the crustose coralline algae (CCA) Porolithon onkodes and P. pachydermum 1,2 , are therefore critical structural elements for the survival of many shallow coral reefs. Concerns are growing about the susceptibility of CCA to ocean acidification because CCA Mg-calcite skeletons are more susceptible to dissolution under low pH conditions than coral aragonite skeletons 3 . However, the recent discovery 4 of dolomite (Mg 0.5 Ca 0.5 (CO 3 )), a stable carbonate 5 , in P. onkodes cells necessitates a reappraisal of the impacts of ocean acidification on these CCA. Here we show, using a dissolution experiment, that dried dolomite-rich CCA have 6-10 times lower rates of dissolution than predominantly Mg-calcite CCA in both high-CO 2 (∼700 ppm) and control (∼380 ppm) environments, respectively. We reveal this stabilizing mechanism to be a combination of reduced porosity due to dolomite infilling and selective dissolution of other carbonate minerals. Physical break-up proceeds by dissolution of Mg-calcite walls until the dolomitized cell eventually drops out intact. Dolomite-rich CCA frameworks are common in shallow coral reefs globally and our results suggest that it is likely that they will continue to provide protection and stability for coral reef frameworks as CO 2 rises.Coralline algae form extensive carbonate structures on the highenergy windward side of many tropical coral reefs. For example, the algal rim on the fringing reef of Rodrigues Island (Indian Ocean) is ∼11 km long, 4 m thick and in parts protrudes ∼1m above the reef flat 6 , providing substantial protection for island communities from high-energy waves. Only the surface veneer (the top few millimetres) of CCA is living 7 and the dense carbonate underneath the algal rim is predominantly in situ CCA skeleton and overlapping layers of coral branches cemented together by CCA crusts 6 . Development of these reef structures is dependent on preservation of the dead CCA skeleton post-mortem. Thus, understanding how declining seawater pH will affect this skeletal preservation is of paramount importance if we are to understand the changes to coral reef structural stability in a high-CO 2 world.In the 1950s-1970s the mineral composition of coralline algae skeletons was determined to be ∼12-18 mol% Mg-calcite [8][9][10] . However, many bulk chemical analyses of tropical coralline algae showed a surplus of magnesium compared with those determined by X-ray diffraction (XRD) using Mg-calcite peak position 8,9 . Recently, we discovered this discrepancy was due to the presence of previously undetected dolomite and magnesite (MgCO 3 ) forming within the cell spaces 4 . Past determinations of thermodynamic solubility for coralline algae were based on the assumption that they were composed of Mg-calcite 10-12 . As dolomite was not believed to form in the modern marine environment, determining d...

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Polysaccharide-catalyzed nucleation and growth of disordered dolomite: A potential precursor of sedimentary dolomite

Cited by 152 publications

References 81 publications

Strategizing Carbon-Neutral Mines: A Case for Pilot Projects

Strategizing Carbon-Neutral Mines: A Case for Pilot Projects

Magnesium isotopic compositions of the Mesoproterozoic dolostones: Implications for Mg isotopic systematics of marine carbonates

Dolomite-rich coralline algae in reefs resist dissolution in acidified conditions

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