Table of Content

20 December 2007, Volume 13 Issue 4

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Article

Mechanisms of Environmental Response to Biomineralization

LU An-huai

2007, 13(4):  613-620. 

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The study of biomineralization and corresponding mechanisms of environmental response can promote the development of biogeology in the interdisciplinary frontier and provide the scientific basis for the new significant pollutant control technology in the environmental fileds. The key scientific issue of this project is the mechanisms of mineral formation/decomposition controlled by life activities and the corresponding response to environmental factors. The main research scope includes the mechanisms of biomineralization, the environmental effects of biomineralization and the controlling theory and methods for biomineralization. The objectives of this project are to develop the theory of biomineralization from a multidisciplinary view, to discover the micro-mechanisms of heavy metal mineralization controlled by bacteria, to propose the principle of microorganism approach for the remediation of heavy metal pollution, to open the coupled mechanisms of POPs degradation by semiconductor minerals and bacteria and then construct a ternary system research method, to understand the decomposition mechanism of metallic sulfide mines accelerated by bacteria, to optimize a controlling means of mineral decomposition by bacteria influencing the eco-environment.

Advances in Microbiologically Mediated Dissolution of MetalSulfides in Polymetallic Mines and Its Environmental Significance

LU Jian-jun

2007, 13(4):  621-629. 

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The dissolution of the metal sulfides in polymetallic mines not only produces acid mining drainage (AMD), but also releases the abundant heavy metals into the surroundings, which results in serious environmental contamination. Existing studies indicate that various microorganisms play important roles in the dissolution of minerals and in the release, transportation, precipitation and enrichment of heavy metals. In this papers, the new approaches on the mechanisms of microbiologically mediated dissolution of minerals, the interfacial processes between microbes and minerals, and the function of biofilms are summarized. The features of microbes community and species phylogeny are discussed. Furthermore, the microbiogeochemical cycles of the heavy metals released by the microbiological dissolution of metal sulfides and the influence of the heavy metals on the microbiological oxidation are reviewed. Finally, the potential applications of microorganisms in the remediation of contaminated environments are also addressed.

Formation of Rust Layer Influenced by Microorganisms on Steel Immersed in Seawater and Its Environmental Effect

DUAN Ji-zhou

2007, 13(4):  631-636. 

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The characteristics of rust layer on steel immersed in seawater and related anaerobic microbial community were investigated. Sulfate-reducing bacteria and iron-reducing bacteria were found in the rust layer by microbial enrichment and molecular biological analysis. The characteristics of rust layer minerals were studied and analyzed by SEM, XRD and EDS. In the outer and middle rust layers, the iron oxides（ including α, β, γ-FeOOH） were found, and the green rust was mainly found in the inner rust layer. The formation and transformation of rust layer minerals under the influence of anaerobic bacteria was discussed on the basis of experimental observation. It is also suggested that microorganisms and related rust layer minerals on steel possibly play an important role in marine microbial remediation.

Study on the Modulating Effect of Polysaccharide upon the Mineralization of Iron Hydroxide

SUN Zhen-ya

2007, 13(4):  637-643. 

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To investigate the modulating effect of polysaccharide upon the mineralization of iron hydroxide, a series of simulative biomineralization experiments using dextran and chitosan as organic substrates were conducted in this paper. The results showed that iron hydroxide gel nucleated and grew in polysaccharide molecule, and the nanometric size akaganeite formed with the self-assembly effect of dextran or chitosan. The shape, size and crystal structure of the iron oxyhydroxide mineral formed from iron hydroxide gel depend on the type of polysaccharide and its concentration.

Effect of Phosphatidylcholine and Glycylglycine on Polymorph and Surface Microstructure of Calcium Carbonate

NI Jie

2007, 13(4):  644-650. 

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Phosphatidylcholine (PC) is one of the basic components of the biomembrane, which plays important roles in the biomineralization. As a double-hydrophilic biomacromolecule, PC can form liposomes in solution and lipid membrane layer at the interface of solution/air. In this paper, using X-ray diffraction (XRD), scanning electron microscope (SEM) and dynamic light scattering (DLS), we systematically investigated mineralization of calcium carbonate in the presence of PC and/or glycylglycine by a biomimetic mineralization approach. As a result, we found that phosphatidylcholine and glycylglycine obviously have effects on surface microstructure of calcium carbonate,and that the electrostatic force interaction between the PC molecules at the interface of solution/air and the dissolved glycylglycine synergically inhibits mineralization of calcium carbonate minerals.

Application of Mesoscopic Methods for Studying the Mechanisms ofMicrobial Mineralization: Using Microbe-Chromium Interactions as an Example

LI Bin

2007, 13(4):  651-656. 

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There are increased interests on investigating the mechanisms of microbial mineralization.Comprehensively using different kinds of analytical methods, such as electron microscopy, atomic force microscopy and X-ray absorption fine structure, the present paper studies the structural transformation information during the process when Ochrobactrum sp. interacts with heavy metal chromium. It is proposed that the investigation of structural information was in nano scale. Together with related molecular biological results, the investigation is helpful in understanding the mechanisms of microbial mineralization.

Influence of Microbe-Mineral Contact Model on Mineral Dissolution: A Primary Study on Microperthite Dissolution by Paenibacillus polymyxa

ZHOU Yue-fei

2007, 13(4):  657-661. 

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Microorganisms can promote the dissolution of silicates by direct and indirect mechanisms. The contribution of both mechanisms to the mineral dissolution varies with the growth stage of microorganisms. By employing microfiltration membrane, this research tried to illustrate the contributions of these two mechanisms to dissolution of microperthite. The results showed that during 96 hours， culturing, Paenibacillus polymyxa and its metabolites can promote dissolving microperthite both by direct and indirect mechanisms. The direct mechanism can promote releasing Al, but has little effect on K and Si， which are considered to be mainly released by indirect mechanism. Direct and indirect mechanisms both show intense effects in stationary and dead phases. During mineral dissolution, consumption of bacteria growth and complexation of bacteria and metabolites are also important factors influencing the concentration of elements. Furthermore, the synergetic effect complicates the ion concentrations.

Study on the Changes of Microbial Ecology with ERIC Method after Cultivation by Different Mineral Resources

XIAO Sheng-mu

2007, 13(4):  662-668. 

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Three samples of acid mine drainage were collected from the Dongxiang copper mine in Jiangxi province,the Yinshan lead-zinc mine in Jiangxi province and the Yunfu sulfide mine in Guangdong province. After the samples were cultivated by different energy resources, the microbial communities were analyzed by enterobacterial repetitive intergenic consensus-PCR （ERIC-PCR） method. The results show that the chemical characters and microbial communities of the samples are very different. The microbial communities would be much different even the same sample was cultivated by different minerals as energy resources. It is also shown that similar compositions of the energies for cultivation result in more similar microbial communities. Furthermore, the reaction system and program of ERIC-PCR method for the acid mineral drainage were optimized.

Adsorption of Silicate Bacteria on Surface of Orthoclase and Biotite and its Selectivity

CHENG Liang-juan

2007, 13(4):  669-674. 

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By using silicate bacteria, orthoclase and biotite, we studied the effects of adsorption time and silicate bacteria concentration on adsorption amount on mineral surface of orthoclase, biotite and their coexistence. The results show that the maxima of adsorption amount per unit area of silicate bacteria on orthoclase and biotite are 40 min and 30 min for bacteria concentration 25×106 /ml and 30×106 /ml, respectively. Both in the system of single mineral system and in the coexisting system, the adsorption amount per unit area of silicate bacteria on orthoclase is always higher than that on biotite. In the coexisting system, silicate bacteria prefer to be adsorbed on the surface of orthoclase. While concentration of silicate bacteria increases, the selective adsorption on orthoclase becomes more dominant. The results provide important evidence for the bioweathering mechanism of minerals.

Experimental Study on Adsorption of Cu2+on Paenibacillus polymyxa

DING Yu

2007, 13(4):  675-681. 

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The microorganisms can clearly affect the mobility of metal ions in the environmental fluids because of abundant chemical groups on the cell surface. Adsorption of ions on the microorganism surface plays important roles in various biogeochemical processes, such as mineralization, nucleation and crystal growth. In order to disclose the adsorption mechanisms and to understand the adsorption capacity of bacteria, this paper experimentally studies the Cu2+ adsorption behavior of a widely occurring bacterium, Paenibacillus polymyxa. Firstly, consecutive acid titration was carried out. The results show that the range of optimum pH at which the Paenibacillus polymyxa absorbs H+ is 7.54 ~ 6.00, and the surface of Paenibacillus polymyxa cell bears abundant negative charges, which determines the ion adsorption capacity. Then, the Cu2+ adsorption isotherm of Paenibacillus polymyxa was measured. As the olution pH increases linearly with the increasing Cu adsorption capacity, it is deduced that the ion exchange between surface H+ and Cu2+ may be the potential mechanism of the apparent adsorption. The data fitting indicates that the biosorption process agrees well with both the Langmuir model and Freundlich model. According to the isotherm equation of Langmuir model, the calculated adsorption capacity of Cu2+ is as high as 1.69×10-7 mg/cell.

Dynamics of Degrading Naphthalene by Bacillus subtilis

FANG Shi-chun

2007, 13(4):  682-687. 

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Bacillus subtilis; naphthalene; degradation; dynamics; configuration model

DGGE Analysis of 16S rDNA for Ammonium Oxidizing Bacteriain Constructed Rapid Infiltrition System (CRI)

MA Ming-chao

2007, 13(4):  688-693. 

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In order to reveal the microbial community distribution of ammonium oxidizing bacteria and the removal mechanism of NH4-N in constructed rapid infiltrition system (CRI), sands of different depths were sampled from CRI in Shenzhen, and were analyzed by denaturing gradient gel electrophoresis (DGGE). The profiles of DGGE show that the microbial community of ammonium oxidizing bacteria increases followed by a decrease from top to bottom. There are about 4~5 species in the upper 10 cm part, and they are composed of microorganisms in sewage or those who played important roles in the biodegradation of organonitrogen. About 9 species are found in CRI between 20 cm and 90 cm in depth, where the nitrosation capacity is stronger. For lack of NH4-N or oxygen, the species of ammonium oxidizing bacteria reduce to 5~6 at the depth below 100 cm. The results will be that, the upper level the ammonium oxidizing bacteria distribute in CRI, the higher the removal rate of NH4-N. The relationship between community distribution of ammonium oxidizing bacteria and the removal rate of NH4-N is meaningful to improve the treatment performance of CRI.

Magmatic Consanguinity of Neoproterozoic Volcanic and Intrusive Rocks in Heshang Area, Hangzhou Region

LU Cheng-zhong

2007, 13(4):  694-702. 

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The Heshang area of Hangzhou region in northwest Zhejiang is a typical place where the Upper Proterozoic volcanic rocks of Shangshu Formation outcrop. In this area, there is also observed the occurrence of Neoproterozoic diabase and hypabyssal, composite intrusive rocks of alkalic feldspar granite. The volcanic rocks and intrusive rocks have close spatial association and close age. They are both products of tectono-magmatic activities in Late Jinning period. The magma eruption and intrusion could be divided into two stages. The rocks formed in each particular stage have similar or identical characteristics in their rock types, petrochemistry and geochemistry. These features indicate that the volcanic and intrusive rocks in each stage have the same magma origin. The basic volcanics in Shangshu Formation and Ciwu diabase, formed in the first stage, were derived from the less-depleted mantle or the magma with the origin of depleted mantle contaminated by continental crust. The acid volcanics in Shangshu Formation and Daolinshan alkalic feldspar granite, formed in the second stage, might be derived from partial melting of crust sources consisting of both basic and acid constituents.

Organic Geochemical Features of Mudstone Source Rock from Member 7 Strata of Middle Jurassic Age in the Northern Margin of Qaidam Basin and Its Hydrocarbon-Generation Potential

LIU Yun-tian

2007, 13(4):  703-713. 

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It has been acknowledged for a long time that in the northern margin of Qaidam Basin, the Lower Jurassic mudstone source rock has a better hydrocarbon generation potential than the Middle Jurassic sequences. In this paper, the hydrocarbon generation potential of a set of lacustrine mudstone source rock sequences developed in the Middle Jurassic Member 7 was discussed comprehensively. Based on geochemical analyses on these source rocks collected from the Yuqia area, and in combination with analytical results reported in previous literature, it is indicated that the J2d7 mudstone belongs to organic-rich source rocks. Organic petrographical micro-observation shows that algae, cutinites and sporophytes mainly constitute organic maceral of these mudstone source rocks, with the type of organic matter reaching II1 as best. Additionally, according to information of maturation, it is suggested that this set of source sequences has undergone different histories in different depressions. This implies that it could generate not only oil, but also gas. Although the distribution and quality of the J2d7 mudstone source rocks are heterogeneous in different depressions, this set of source rocks has good hydrocarbon generation capabilities no worse than the Lower Jurassic ones and enough attention should be paid in the future petroleum geologic exploration and research.

Effects of Paleogene Formation Water on Physical Properties of Reservoirs in Shengli Oil Zone

WANG Wei

2007, 13(4):  714-721. 

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Taking Paleogene of Shengli Oil Field as an example and using statistic method and microscopic data,the analysis of distribution and evolution characteristics of formation water in research area was made, and the mechanism of formation water effects on reservoir properties was studied. It is considered that for a given identical sedimentary basin, the formation water (which is influenced by depositional environment) is the basic factor that affects the reservoir diagenesis, and its spatial distribution affects the evolution of the reservoir physical properties. There exist 4 types of co-relationship between formation water and reservoir physical properties. Through the integrated consideration of formation water salinities, carbonate contents and reservoir properties, the diagenetic environment and evolution of reservoir properties can be estimated.

Experimental Studies on Fluid Inclusions in Hydrothermal Anhydrite：Effects of the Formation of Gypsum

WU Xue-mei

2007, 13(4):  722-729. 

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Hydrothermal anhydrite [CaSO4] is a good host for primary and secondary fluid inclusions. It is also potentially a problematic host for stretching of inclusions, partial dissolution and precipitation of anhydrite, and formation of gypsum from reaction of anhydrite with the trapped aqueous fluid. Microthermometric experiments on liquid/vapor inclusions in anhydrite from Juan de Fuca Ridge show that new daughter crystals, identified to be the low-temperature hydrate gypsum [CaSO4?2H2O], commonly develop during freezing experiments (~-50℃).This phenomenon has been recognized for over 20 years, but its occurrence and significance to the determination of inclusion salinities are not widely appreciated. There is growing evidence that hydration of the host anhydrite may significantly lower the ice melting temperature and increase the salinity of the residual inclusion fluid. The present study shows that the salinities of inclusions increase largely after gypsum formed in liquid/vapor inclusions (salinities increase 0.32 to 1.6% NaCl eq.). We propose that gypsum is the product of both anhydrite hydration and supersaturation with respect to gypsum, but mainly owing to the former. Heating inclusions to decompose gypsum results in the release of bound water, restoring the inclusions to their original salinities. So when gypsum formation occurs during freezing experiments, it needs to be dehydrated periodically through heating to about 130℃. These processes could have no impacts on the real homogenization temperatures of inclusions.

Determination of Goethite and Hematite in Red Clay by Diffuse Reflectance Spectroscopy

ZHOU Wei

2007, 13(4):  730-736. 

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Goethite (Gt) and hematite (Hm) are important iron minerals in soils and sediments. However, conventional measurements can not effectively distinguish them in the low concentrations typical of soils and sediments. In this paper we demonstrate that diffuse reflectance spectroscopy (DRS) in conjunction with thermal treatment provides a definitive technique for identifying and estimating concentrations of Gt and Hm in soils and sediments. The DRS pattern of Gt exhibits diagnostic changes of the first derivative value (FDV) peaks after heating to 300℃. Hm can be identified by its FDV peak without heating because it displays no shift in peak wavelength after heating. The degree of thermal change induced in a sample depends on the concentrations of both Gt and Hm. Application of this technique to the samples of the Tertiary red clay from Loess Plateau indicates the concentrations of about 0.3~0.4% for Hm and 0.5~1% for Gt.