Effect of Mineral Dusts on the Growth of Silicate Bacteria S35

In order to compare the chemical compositions and physical properities of dusts on silicate bacteria S35, the chemical compositions of six kinds of mineral dusts have been analyzed and the changes of pH value, glucose （GLU）, electrolyte and Mn, Si, Fe before and after the dusts reacted with silicate bacteria S35 have been measured. The SEM analysis has been used to study the bacterial form and interface action status in the course of reaction between dusts and bacteria. The results show that these mineral dusts have different effects on experiment bacteria. Therefore, it is concluded that the effect of mineral dusts on silicate bacteria has correlation with the chemical compositions and physical properities of dusts.     

几种矿物粉尘对硅酸盐细菌S35生长的影响

通过对6种矿物粉尘主要化学成分的分析,以及它们与硅酸盐细菌S35的相互作用后各培养液pH值、葡萄糖(GLU)、电解质以及Mn、Si、Fe等的变化的测试,比较矿物粉尘的化学成分和物理性状对试验目标菌生长的影响。利用SEM分析对粉尘与细菌的作用过程中细菌形态和界面作用情况进行了研究。结果表明,所选各种矿物粉尘对细菌生长情况的影响存在差异,矿物粉尘对硅酸盐细菌生长的影响可能与粉尘的化学成分有关。     

The effect of Fe on Si adsorption by Bacillus subtilis cell walls: insights into non-metabolic bacterial precipitation of silicate minerals

Si adsorption onto Bacillus subtilis and Fe and Al oxide coated cells of B. subtilis was measured both as a function of pH and of bacterial concentration in suspension in order to gain insight into the mechanism of association between silica and silicate precipitates and bacterial cell walls. All experiments were conducted in undersaturated solutions with respect to silicate mineral phases in order to isolate the important adsorption reactions from precipitation kinetics effects of bacterial surfaces. The experimental results indicate that there is little association between aqueous Si and the bacterial surface, even under low pH conditions where most of the organic acid functional groups that are present on the bacterial surface are fully protonated and neutrally charged. Conversely, Fe and Al oxide coated bacteria, and Fe oxide precipitates only, all bind significant concentrations of aqueous Si over a wide range of pH conditions. Our results are consistent with those of Konhauser et al. [Geology 21 (1993) 1103; Environ. Microbiol. 60 (1994) 49] and Konhauser and Urrutia [Chem. Geol. 161 (1999) 399] in that they suggest that the association between silicate minerals and bacterial surfaces is not caused by direct Si–bacteria interactions. Rather, the association is most likely caused by the adsorption of Si onto Fe and Al oxides which are electrostatically bound to the bacterial surface. Therefore, the role of bacteria in silica and silicate mineralization is to concentrate Fe and Al through adsorption and/or precipitation reactions. Bacteria serve as bases, or perhaps templates, for Fe and Al oxide precipitation, and it is these oxide mineral surfaces (and perhaps other metal oxide surfaces as well) that are reactive with aqueous Si, forming surface complexes that are the precursors to the formation of silica and silicate minerals.     

Dissolved silicate dynamics of the Rhode River watershed and estuary

We continuously measured dissolved silicate concentrations and fluxes discharged from various Rhode River subwatersheds for a period of 14 yr from 1984 to 1998 and for 15 mo in 1971–1972. We also measured dissolved silicate concentrations along a transect from the head of the tide in Rhode River estuary to Chesapeake Bay. The average concentration of dissolved silicate discharged from the Rhode River watershed was 10.8 mg Si l^?1. There were consistent and significant differences in silicate concentrations discharged over time and space among subwatersheds. Mean annual silicate flux from the watershed was 26.6 kg Si ha^?1 and 93% of this occurred during the winter and spring seasons. There were large interannual variations in silicate flux, due primarily to differences in precipitation and water discharge, rather than silicate concentration. Land use had little or no effect on silicate flux from various subwatersheds. Silicate concentrations discharged from a subset of subwatersheds in 1995–1996 were 25% to 35% lower than in a period with similar precipitation in 1971–1972. Mean annual concentrations of silicate discharged from nine subwatersheds have been declining about 1.5% yr^?1 or by 0.21–0.26 mg Si l^?1 yr^?1 over the last 25 yr. Despite high average silicate fluxes from the watershed, at times the Rhode River estuary developed low dissolved silicate concentrations, which could have been limiting to the growth of diatoms. Examples were in the spring after a winter with low watershed discharge (as low as 0.019 mg Si l^?1 in 1995) and after protracted drought (as low as 0.041 mg Si l^?1 in 1993).     

硅酸盐细菌煤炭脱硫实验研究

煤炭生物脱硫技术是目前和将来的重要研究内容之一.采用生长在含高硫煤培养基中的硅酸盐细菌来去除煤炭中的硫.研究结果表明,硅酸盐细菌对所用高硫煤样有脱硫效果,全硫含量从原煤样的5.45%降至处理后的3.45%,全硫脱除率达36.70%,其中细菌有效脱除率达9.91%.摇床培养的硅酸盐细菌比静止培养的硅酸盐细菌对煤炭脱硫效果更好.含氮培养基培养的硅酸盐细菌比无氮培养基培养的硅酸盐细菌脱硫效果要好.初步研究结果显示,硅酸盐细菌不仅对煤中硫化铁硫存在氧化作用,同时也对煤中有机硫和无机硫存在吸收与代谢转化作用.认为硅酸盐细菌对煤炭的脱硫作用存在两种机理:①硅酸盐细菌及其代谢产物对煤中硫产生氧化作用;②硅酸盐细菌对煤中硫进行了吸收与代谢转化.两种机理同时存在,且作用对象包括煤中所有形态的硫.该实验结果显示硅酸盐细菌在脱硫研究中有潜在应用前景.     

新疆巴里坤膨润土的红外光谱分析

对巴里坤膨润土不同颜色的典型样品进行红外光谱测试分析,结果表明:巴里坤膨润土矿Ⅱ的膨润土的强吸收波谱出现在3627 cm-1(高频区)、1040 cm-1(中频区)、531 cm-1、470 cm-1(低频区)附近;5个代表样品的红外光谱曲线轮廓基本上一致,但仍存在一定的差异,不同颜色的膨润土因其化学成分的差异,在红外光谱曲线上有所不同,在3600 cm-1(高频区)附近,1#样品对红外光谱的吸收率较强,归属于Al—O—H的伸缩振动,说明1#样品蒙脱石的含量要高些;在797.64 cm-1(中频区)附近,1#、5#样品对红外光谱的吸收率要弱些,归属于Si—O—Si的反对称伸缩振动,说明SiO2的含量较低。     

索伦石的晶体结构

索伦石是1961年在我国发现的一种新矿物。成分为CaO·SiO₂·H₂O,是人工和天然的含水硅酸钙矿物中CaO∶SiO₂∶H₂O=1:1:1的唯一一种矿物,因此索伦石结构的测定对了解这一类矿物的晶体化学当有助益。     

机械力化学改性硅灰石表面行为TEM的研究

选用气流磨超音速气流作为机械力,对硅灰石、硬脂酸进行超细粉碎－表面改性。应用透射电子显微镜分析、观察硅石灰／硬脂酸复合粉体界面微观形貌及成分（Ｃａ、Ｓｉ、Ｃ）的变化规律。ＴＥＭ能谱分析结果表明：从硅灰石到硬脂酸,Ｃａ、Ｓｉ含量逐渐降低,Ｃ含量则逐渐升高。     

Calc-silicate reactions and bedding-controlled isotopic exchange in the Notch Peak aureole, Utah: implications for differential fluid fluxes with metamorphic grade

Fluid compositions and bedding‐scale patterns of fluid flow during contact metamorphism of the Weeks Formation in the Notch Peak aureole, Utah, were determined from mineralogy and stable isotope compositions. The Weeks Formation contains calc‐silicate and nearly pure carbonate layers that are interbedded on centimetre to decimetre scales. The prograde metamorphic sequence is characterized by the appearance of phlogopite, diopside, and wollastonite. By accounting for the solution properties of Fe, it is shown that the tremolite stability field was very narrow and perhaps absent in the prograde sequence. Unshifted oxygen and carbon isotopic ratios in calcite and silicate minerals at all grades, except above the wollastonite isograd, show that there was little to no infiltration of disequilibrium fluids. The fluid composition is poorly constrained, but X(CO₂)_fluid must have been >0.1, as indicated by the absence of talc, and has probably increased with progress of decarbonation reactions. The occurrence of scapolite and oxidation of graphite in calc‐silicate beds of the upper diopside zone provide the first evidence for limited infiltration of external aqueous fluids. Significantly larger amounts of aqueous fluid infiltrated the wollastonite zone. The aqueous fluids are recorded by the presence of vesuvianite, large decreases in δ¹⁸O values of silicate minerals from c. 16‰ in the diopside zone to c. 10‰ in the wollastonite zone, and extensive oxidation of graphite. The carbonate beds interacted with the fluids only along margins where graphite was destroyed, calcite coarsened, and isotopic ratios shifted. The wollastonite isograd represents a boundary between a high aqueous fluid‐flux region on its higher‐grade side and a low fluid‐flux region on its lower‐grade side. Preferential flow of aqueous fluids within the wollastonite zone was promoted by permeability created by the wollastonite‐forming reaction and the natural tendency of fluids to flow upward and down‐temperature near the intrusion‐wall rock contact.     

优化处理红宝石中轻微玻璃态物质的清理实验

针对目前市场上出现的一些因优化处理而产生轻微玻璃残余物的天然红宝石,经适当浓度的氢氟酸(浓度23%)浸泡后,位于红宝石内裂隙和表面凹坑中的轻微玻璃态残余物被溶解,达到清理玻璃态残余物的目的,并利用电感耦合等离子体-原子发射光谱仪(ICP-AES)分析含玻璃材料的溶液中Si和Al的浓度分别为28.60μg/mL和2.795μg/mL,进而估算玻璃态残留物的损失量以判定热处理过程中非人为加入的玻璃态物质在红宝石中的充填程度。利用红外光谱仪对玻璃残留物清理前后的红宝石红外光谱进行对比研究得出:清理前,红外光谱显示在1 100~1 000 cm-1内有1个单峰宽谱带,谱峰为1 050 cm-1,是由νas(Si—O—Si)非对称伸缩振动引起的,表明残留物为非晶质体,750~600 cm-1之间位于744 cm-1的吸收峰为νs(Si—O—Si)对称伸缩振动引起;清理后,未检测到玻璃残余物特征的Si—O振动峰,仅具950~600 cm-1范围内的宽谱带,为刚玉Al—O基频振动谱带736、622 cm-1,体现晶质金属氧化物的特征,表明样品中玻璃态物质已被清除,实验后红宝石可被划归为经人工优化范畴。宝石显微镜下观察到清理实验后红宝石中原先被玻璃残余物所掩盖的显著内裂隙及表面凹坑。     

蛇绿岩中铬铁岩母岩浆的富Ca特征:矿物包裹体证据

铬铁矿作为蛇绿岩中的重要矿产,其成矿母岩浆性质及演化一直存在较大争议.铬铁矿的矿物包裹体同时或先于铬铁矿结晶,其成分和类别能很好地记录成矿母岩浆性质和演化过程.土耳其Pozant?-Karsant?蛇绿岩不同类型铬铁岩的铬铁矿中发现了多种类型包裹体:不含水硅酸盐矿物（如橄榄石和单斜辉石）、含水硅酸盐矿物（如角闪石和金云母）、复合型矿物包裹体（如蛇纹石、硅灰石和单斜辉石的复合型包裹体）和不常见矿物（如磷灰石、铂族元素硫化物）.含水矿物包裹体的出现以及矿物的高Mg#特征（如橄榄石Fo=95.4~97.1;单斜辉石Mg#=92.0~99.9;角闪石Mg#=88.9~99.8）表明结晶铬铁矿的母岩浆具有富水、富Mg的特征.同时,除钙铬榴石和磷灰石的包裹体外,在铬铁矿中首次发现富Ca矿物方解石和硅灰石,其中方解石和菱镁矿以复合型包裹体形式产出,硅灰石则分布于蛇纹石矿物包裹体中.这些富Ca矿物的出现以及硅酸盐矿物的高CaO含量均揭示了铬铁岩母岩浆的富Ca特征.母岩浆中的Ca组分可能来源于俯冲板块中富Ca岩石/矿物的部分熔融,Ca离子的大量出现使得Cr3+在熔体中更加稳定,同时富Ca矿物的结晶促进了岩浆中Cr的进一步富集而利于铬铁矿的大量结晶沉淀.      

硅灰石矿化学物相分析方法

硅灰石是一种钙的偏硅酸盐矿物,它作为工业矿物仅有二十多年的历史。从六十年代起,硅灰石用作陶瓷原料有了迅速地发展,由于能低温快速烧成,可大幅度降低燃料消耗,缩短生产周期,提高生产率。因此,大量用于釉面砖的生产。此外,硅灰石还在涂料工业、塑料与橡胶工业、磨料工业、电焊和绝缘产品等方面也得到应用,特别是把硅灰石处理成超细粒材料后,更有广阔的发展前景。     

Rock weathering by indigenous heterotrophic bacteria of Bacillus spp. at different temperature: a laboratory experiment

The bio-weathering of basalt, granite and gneiss was experimentally investigated in this study. These rock-forming minerals weathered more rapidly via the ubiquitous psychrotrophic heterotrophic bacteria. With indigenous bacteria of Bacillus spp. from sediments of Lake Baikal, we traced the degradation process of silicate minerals to understand the weathering processes occurring at the change temperature in the subsurface environment with organic input. The bacteria mediated dissolution of minerals was monitored with solution and solid chemistry, X-ray analyses as well as microscopic techniques. We determined the impact of the bacteria on the mineral surface and leaching of K, Ca, Mg, Si, Fe, and Al from silicate minerals. In the samples the release of major structural elements of silicates was used as an overall indicator of silicate mineral degradation at 4°C and 18°C from five medium exchanges over 255?days of rock bioleaching. The increase of temperature importantly affected the efficiency of Fe extraction from granite and basalt as well as Si extraction from granite and gneiss. In comparison with elemental extraction order at 4°C, Ca was substituted first by Fe or Si. It is evident that temperature influences rock microbial weathering and results in a change of elements extraction.     

四川石棉县蛇纹石猫眼的红外吸收光谱研究

采用Fourier变换红外吸收光谱和X射线粉晶衍射技术对四川石棉县蛇纹石猫眼进行了研究。红外吸收光谱结果表明:四川蛇纹石猫眼可分为纤蛇纹石和叶蛇纹石两种类型,两者在(960-1100)cm-1和(3600-3690)cm-1的范围内由Si-O伸缩振动的E1类振动和OH伸缩振动表现出的红外谱带分裂强度及谱带特征存在明显的差异。在(960- 1100)cm-1间:纤蛇蚊石的红外光谱分裂成三个明显的谱带,而叶蛇纹石在此区间只有两条谱带。在570cm-1附近的红外谱带以肩状出现;OH伸缩振动区:纤蛇蚊石出现两条红外谱带,而叶蛇蚊石只出现一条红外谱带。X射线粉晶衍射结果表明:叶蛇蚊石具有d202=0．2522nm(I/I0=19)和d203=0．2430nm(I／I0=18)的特征谱线,而纤蛇纹石则具有d202、006=0．2446nm(I／I0=29)的特征谱线,d020>0．245nm近0．249 nm的特征谱线缺失。     

A multinuclear,high-resolution solid-state NMR study of sorensenite (Na4SnBe2(Si3O9)·2H2O) and comparison with wollastonite and pectolite

This paper presents a solid state ¹H, ²³Na, ²⁹Si, and ¹¹⁹Sn nuclear magnetic resonance (NMR) study of sorensenite. New ²⁹Si NMR data for two related pyroxenoids, wollastonite and pectolite, are included for comparison. By more sensitively probing chemical bonding, the element-specific NMR observations both complement and reinforce the x-ray diffraction results. The role of hydrogen and its interactions with neighboring atoms in sorensenite is further clarified. The wollastonite and pectolite ²⁹Si spectra resolve for the first time all three crystallographic sites and their comparison with sorensenite reveals subtle, systematic differences in sites along the pyroxenoid chains. Effects of corner-shared BeO₄ tetrahedra on ²⁹Si shifts show that sorensenite may also be viewed as a more polymerized silicoberyllate. Contribution to the mineralogy of Ilimaussaq No. 86     

Monitoring the crystallization of water-saturated granitic melts in real time using the hydrothermal diamond anvil cell

Critical aspects of the crystallization dynamics of H₂O-saturated melts of a typical granitic composition as well as granitic melts enriched in lithium (8800 ppm) were investigated in real-time experiments using the hydrothermal diamond anvil cell at 480–700 °C and 220–960 MPa. Complete crystallization of the charges was achieved within 5–118 h with average crystal growth rates ranging from 3 to 41 cm/year for quartz and from 18 to 58 cm/year for alkali feldspars, demonstrating that crystals formed from a silicate melt in the presence of a coexisting aqueous phase crystallize rapidly. The combination of substantial nucleation delays, low nucleation densities, and rapid growth rates for quartz and alkali feldspars led to the formation of euhedral megacrysts of these minerals in the vicinity of clusters comprised of much smaller muscovite or α-spodumene crystals. Subsolidus replacement processes initiated during crystal–fluid interactions after the silicate melt was consumed were directly observed in the experiments. The experimental results underscore the important role of water as a medium for the transport of essential elements such as Si, Al, Na, and K from the silicate melt to the newly formed crystals, and provide important insights into the crystallization of miarolitic pegmatites.     

Impact of recharge water temperature on bioclogging during managed aquifer recharge: a laboratory study

To investigate the effect of recharge water temperature on bioclogging processes and mechanisms during seasonal managed aquifer recharge (MAR), two groups of laboratory percolation experiments were conducted: a winter test and a summer test. The temperatures were controlled at ~5±2 and ~15±3 °C, and the tests involved bacterial inoculums acquired from well water during March 2014 and August 2015, for the winter and summer tests, respectively. The results indicated that the sand columns clogged ~10 times faster in the summer test due to a 10-fold larger bacterial growth rate. The maximum concentrations of total extracellular polymeric substances (EPS) in the winter test were approximately twice those in the summer test, primarily caused by a ~200 μg/g sand increase of both loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS). In the first half of the experimental period, the accumulation of bacteria cells and EPS production induced rapid bioclogging in both the winter and summer tests. Afterward, increasing bacterial growth dominated the bioclogging in the summer test, while the accumulation of LB-EPS led to further bioclogging in the winter test. The biological analysis determined that the dominant bacteria in experiments for both seasons were different and the bacterial community diversity was ~50% higher in the winter test than that for summer. The seasonal inoculums could lead to differences in the bacterial community structure and diversity, while recharge water temperature was considered to be a major factor influencing the bacterial growth rate and metabolism behavior during the seasonal bioclogging process.     

Experimental study on weathering of seafloor volcanic glass by bacteria (Pseudomonas fluorescens) – Implications for the contribution of bacteria to the water–rock reaction at the Mid-Oceanic Ridge setting

The biologically mediated weathering of the ocean crust has received increasing attention in recent decades, but the rates and the possible mechanism of elemental release during microbe–basalt interactions occurring below the seafloor have not been studied in detail. In this study, we established an experimental weathering study of seafloor natural basaltic glass comparing the effect of microbial activity (Pseudomonas fluorescens) in P-rich and P-poor media with parallel controls containing either nonviable cells or organic acid. The changes in the chemical parameters, including pH, bacterial densities, and ion concentrations (Ca, Mg, Si, Mn, Al, Fe, and P) in the solution, were examined during the different batch experiments. The results showed that the pH decreased from 7.0 to 3.5 and the bacterial density increased from 10⁵ to 10⁸ cells/ml during the first 120 h, and the cell numbers remained constant at 10⁸ cells/ml and the pH increased from 3.5 to 6 between 120 h and 864 h in the P-bearing reactors containing bacteria. In contrast, during all the experimental time, the pH remained close to neutral condition in the abiotic control systems and the dissolution rates increased markedly with a decrease in pH and became minimal at near-neutral pH in P-bearing reactors containing bacteria, where Ca, Si, and Mg release rates were 2- to 4-fold higher than those obtained in chemical systems and biotic P-limited systems. Furthermore, the surfaces of the natural volcanic glass from the biotic systems were colonized by bacteria. Simultaneously, the etch pits were observed by Scanning Electron Microscope, which further indicate that the bacteria may promote the mineral dissolution for energy gain. Some elements (e.g., Fe, Mn, and Al) releasing from natural volcanic glass are likely an important source of the elemental budget in the ocean, and thus the element release and its possible mechanism conducted in this experimental study have potential implications on the biogeochemical cycling process in the Mid-Oceanic Ridge setting.     

A mechanism for pyroxene-pyroxenoid and pyroxenoid-pyroxenoid transformations

A mechanism for the solid state replacement of clinopyroxene by pyroxenoids has been derived from consideration of the crystal structures. The mechanism involves the propagation of partial dislocations, with Burgers vectors of 1/4 \([2\bar 3\bar 1]\) , through the clinopyroxene matrix to generate a resultant shear; the passage of one dislocation gives rise to a single chain-repeat unit of wollastonite in each silicate chain. Pyroxenoids may thus be formed from clinopyroxene by the periodic introduction of these dislocations on parallel slip-planes, and pyroxenoid to pyroxenoid inversions may proceed by the introduction and removal of such shears by the propagation of the correct combination of partial dislocations. The Burgers vectors for these dislocations in each of the pyroxenoid mineral structures has been calculated. A two step mechanism is proposed for clinopyroxene to bustamite, and pyroxenoid to bustamite inversions, which utilises the same shear as above which generates a wollastonite structure. The second step is a shear of 1/2[001] on the plane \((1\bar 10)\) of this wollastonite intermediate, to give a bustamite structure.     

污水处理系统中活性污泥细菌多样性研究

采用分子生物学手段16S rDNA克隆文库方法对北京高碑店污水处理厂回流污泥中的细菌进行了多样性研究。结果表明,活性污泥系统中细菌群落具有高度多样性,所有克隆子分属5个不同的细菌类群,优势细菌类群为变形菌(proteobacteria),占克隆文库的76.7%;细菌类群优势依次为β-变形菌类群(β-proteobac-teria,占39.8%)、不可培养菌类群(uncultured bacteria,占22.33%)、γ-变形菌类群(γ-proteobacteria,占20.15%)、α-变形菌类群(α-proteobacteria,占6.79%)和δ-变形菌类群(δ-proteobacteria,占4.85%);活性污泥中起硝化作用的主要是亚硝化单胞菌(Nitrosomonas sp.,占1.94%)和硝化螺旋菌(uncultured Nitrospirae bacterium,占11.65%),由于这2种硝化菌自身生长缓慢,难以与异养细菌竞争,以致其在文库中的比例较低;而作为反硝化细菌的陶厄氏菌属在文库中的比例却高达27.18%,可见该活性污泥具有较强的反硝化能力;克隆文库中还发现了少量的玫瑰单胞菌属(占4.85%),推测它的存在和有机磷的降解有关。