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Interactions between Bacillus mucilaginosus and silicate minerals(weathered adamellite and feldspar):weathering rate,products,and reaction mechanisms

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Chinese Journal Of Geochemistry 2011年第2期30卷 187-192页

作者： Mo, Binbin Lian, Bin State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Bacillus mucilaginosus is a common soil bacterium,and usually used as a model bacterium in studying microbe-mineral interactions.Several reaction mechanisms of B.mucilaginosus weathering silicate minerals were proposed.However,the molecule mechanisms and detailed processes were still unclear.In this paper,bacterium-mineral interactions were studied in terms of variations in pH value over the experimental period,variations in mineral composition,weathering rates of silicate minerals and volatile metabolites in the culture medium,etc.,to further explore the bacterium-mineral interaction mechanisms.The results showed that B.mucilaginosus could enhance silicate mineral weathering obviously.The weathering rates were quite different for various kinds of silicate minerals,and the weathering rate of weathered adamellite could reach 150 mg/m2/d.Although B.mucilaginosus produced little acidic substance,pH in the microenvironment of bacterium-mineral complex might be far lower than that of the circumjacent environment;a large amount of acetic acid was found in the metabolites,and was likely to play an important role as a ligand.These results appear to suggest that acidolysis and ligand degradation are the main mechanisms of B.mucilaginosus dissolving silicate minerals,the formation of bacterium-mineral complexes is the necessary condition for the bacteria weathering silicate minerals,and extracelluar polysaccharides played important roles in bacterium-mineral interaction processes by forming bacterium-mineral complexes and maintaining the spe-cial physicochemical properties of microenvironment.

关键词： Bacillus mucilaginosus silicate mineral interaction weathering rate mechanism

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Biological weathering of phlogopite during enriched vermicomposting

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Pedosphere 2021年第3期31卷 440-451页

作者： Fariba JAFARI Hossein KHADEMI Vajihe SHAHROKH Angel FAZ CANO Jose A.ACOSTA Farhad KHORMALI Department of Soil Science College of AgricultureIsfahan University of TechnologyIsfahan 84156-83111Iran Sustainable Use Management and Reclamation of Soil and Water Research GroupUniversidad Politécnica de CartagenaPaseo Alfonso ⅩⅢ48CartagenaMurcia 30203Spain Department of Soil Science Gorgan University of Agricultural Science and Natural ResourcesGorgan 49189-43464Iran

As the dominant macrofauna in many soils,earthworms play a significant role in mineral weathering and nutrient release from mineral structures into available forms for root uptake.Phlogopite is a trioctahedral micaceous mineral that can be weathered to other minerals through release of its interlayer potassium(K).In this study,we investigated the effect of earthworm activities and associated microbial communities on phlogopite weathering during the production of phlogopite-enriched vermicompost with different quantities of phlogopite added.An experiment was run under laboratory conditions using three levels of phlogopite(0,20%and 40%by weight)in triplicates.Each Petri dish contained 20 g of a mixture of cow manure and phlogopite,and vermicomposting process was performed by inoculation of eight Eisenia foetida earthworms.Changes in clay mineralogy and C/N ratio in each dish were assessed at days 0,45,90,135,and 180 during vermicomposting.The results indicated that phlogopite was partially weathered to vermiculite and interstratified mica-vermiculite during the vermicomposting process.The rate of weathering was higher during the early stages of vermicomposting(the first 90 d).The weathering of phlogopite was influenced considerably by the activity of earthworms and associated microbial communities during the organic matter transformation process.At the early stages of the process,the weathering rate for different levels of phlogopite was not significantly different,but over time it accelerated steadily,and the difference increased.

关键词： C/N ratio earthworm Eisenia foetida enriched vermicompost mineral weathering weathering rate X-ray diffraction

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Sr isotope evolution during chemical weathering of granites——impact of relative weathering rates of minerals

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Science China Earth Sciences 2001年第8期44卷 726-734页

作者：马英军刘丛强 Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

The Sr isotopic systematics in the weathering profiles of biotite granite and granite porphyry in southern Jiangxi Province were investigated. The results showed that during the chemical weathering of granites, remarked fractionation occurred between Rb and Sr. During the early stages of chemical weathering of granites, the released Sr/Si and Sr/Ca ratios are larger than those of the parent rocks, and the leaching rate of Sr is higher than those of Si, Ca, K, Rb, etc. Dynamic variations in relative weathering rates of the main Sr-contributing minerals led to fluctuation with time in 87Sr/86Sr ratios of inherent and released Sr in the weathering crust of granite. Successive weathering of biotite, plagioclase and K-feldspar made 87Sr/86Sr ratios in the weathering residues show such a fluctuation trend as to decrease first, increase, and then decrease again till they maintain stable. This work further indicates that when Sr isotopes are used to trace biogeochemical processes on both the catchment and global scales, one must seriously take account of the prefer-ential release of Sr from dissolving solid phase and the fluctuation of 87Sr/86Sr ratios caused by the variations of relative weathering rates of Sr-contributing minerals.

关键词： Sr isotope chemical weathering weathering rate non-stoichiometry granite.

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weathering rates of a sandstone structure in a semi arid environment:a case study of the ancient city of Pingyao(world cultural heritage),China

Weathering rates of a sandstone structure in a semi arid env...

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中国科学院地质与地球物理研究所第11届（2011年度）...

作者： Zhongjian Zhang·Zhifa Yang·Sijing Wang·Luqing Zhang Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics Chinese Academy of Sciences,Beijing,China

The values of surface recessions of sandstones in the bottom walls of the ancient World Heritage City of Pingyao were measured using a specially designed movable instrument with the precision of 0.0143 mm.Seventeen sample areas were chosen from four orientations to study the effect of weathering in this semi-arid,unpolluted environment.Each area could be sub-divided into three zones with different weathering degrees but the weathering rates were found to be highest in the south-facing and lowest in the north-facing sandstone walls.The reasons for the differential weathering are discussed and recommendations are made to reduce their effects.

关键词： weathering rate Sandstone Semiarid environment Pingyao

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Carbonate weathering rates in the Jura Mountains, France—The influence of vegetation

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Acta Geochimica 2006年第S1期 2-2页

作者： Jérme Gaillardet Damien Calmels Louis Franois Laboratoire de Géochimie et Cosmochimie Univ. Paris 7 Institut de Physique du Globe de Paris 4 place Jussieu 75252 Paris cedex 05 France Laboratoire de Physique Atmosphérique et Planétaire Université de Liège Belgium

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