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Song W.,Xinjiang Institute of Ecology and Geography | Zhao C.,Xinjiang Academy of Environmental Protection science | Zhang D.,Xinjiang Institute of Ecology and Geography | Zhang D.,Institute of Geochemistry Chinese Academy of science | And 2 more authors.
Frontiers in Microbiology | Year: 2016

The effects of UV-B radiation (UVBR) on photosynthetic activity (Fv/Fm) of aquatic Synechocystis sp. and desert Chroococcus minutus and effects on composition and fluorescence property of extracellular polymeric substances (EPSs) from Synechocystis sp. and C. minutus were comparatively investigated. The desert cyanobacterium species C. minutus showed higher tolerance of PSII activity (Fv/Fm) to UVBR than the aquatic Synechocystis sp., and the inhibited PSII activity of C. minutus could be fully recovered while that of Synechocystis sp. could be partly recovered. UVBR had significant effect on the yield and biochemical composition of EPS of both species. Protein-like and humic acid-like substances were detected in EPS from Synechocystis sp., and protein-like and phenol-like fluorescent compounds were detected in EPS from C. minutus. Proteins in EPS of desert and aquatic species were significantly decomposed under UVBR, and the latter was more easily decomposed. The polysaccharides were much more resistant to UVBR than the proteins for both species. Polysaccharides of Synechocystis sp. was degraded slightly but those of C. minutus was little decomposed. The higher tolerance to UVBR of the desert cyanobacterium can be attributed to the higher resistance of its EPS to photodegradation induced by UVBR in comparison with the aquatic species. © 2016 Song, Zhao, Zhang, Mu and Pan.

Wang F.,Shanghai University | Yu Y.,CAS Research Center for Eco Environmental Sciences | Liu C.,Institute of Geochemistry Chinese Academy of science | Wang B.,Institute of Geochemistry Chinese Academy of science | And 3 more authors.
Science of the Total Environment | Year: 2010

Presently, the fluvial fluxes of Dissolved silicate (DSi) by many famous rivers in the world have been reported significantly decreased in the past several decades. DSi retention by river damming hence becomes a great concern. In this study, the impact on DSi retention and transport by cascade reservoirs in the Karst area were investigated. Based on the monitoring data for four seasons, budget of DSi in these reservoirs were calculated. Results showed that, only the downstream eutrophic Wujiangdu reservoir (WJD) was the sink for DSi, with a value of ca. 3.5 kT DSi trapped annually. The new Hongjiadu reservoir (HJD) in the headwater area revealed to be an important source for DSi. Both Dongfeng (DF) and Suofengyin (SFY) reservoirs also released more DSi to the downstream than entering them. The great discrepancy of DSi source and sink effects among these reservoirs indicates that, (i) DSi was obviously taken up in summer and spring, and the concentration of DSi could be dropped down to below 30μΜ; (ii) during the period of thermal stratification, the concentration stratification of DSi is also developed along the water column. Possibly DSi releasing from inundation soil and bottom sediment was the important compensation for the silicon depletion in the epilimnion. In the newly constructed reservoirs (e.g. HJD and SFY), the releasing flux of DSi can significantly exceed the assimilating flux by diatom; and (iii) due to the hypolimnion introducing for hydropower operation, water leaving the dam generally had high DSi content, and then masked the DSi taking up in the epilimnion. This process also decreased the ratio of DIN to DSi, mitigating the silicon limiting situation in the downstream. © 2010 Elsevier B.V.

Zhang D.,Institute of Geochemistry Chinese Academy of science | Zhang D.,Xinjiang Institute of Ecology and Geography | Pan X.,Xinjiang Institute of Ecology and Geography | Mostofa K.M.G.,Institute of Geochemistry Chinese Academy of science | And 8 more authors.
Journal of Hazardous Materials | Year: 2010

The three-dimensional excitation emission matrix (EEM) fluorescence spectroscopy was employed to investigate the interaction of extracellular polymeric substances (EPS) from natural biofilm with Hg(II). The EEM spectra demonstrated that EPS with molecular weight over 14 kDa had two protein-like fluorescence peaks. The fluorescence intensity at both peaks was strongly dependent on the solution pH in the absence and presence of Hg(II), with the maximal fluorescence intensity at neutral pH. Fluorescence of both protein-like peaks was significantly quenched by Hg(II). The values of conditional stability constants (log Ka = 3.28-4.48) derived from modified Stern-Volmer equation are approximate to those for humic substances and dissolved organic matter (DOM), indicating that fluorescent components in EPS have strong binding capacity for Hg(II). Our findings suggest that EPS from biofilm is a class of important organic ligands for complexation with Hg(II) and may significantly affect the chemical forms, mobility, bioavailability and ecotoxicity of heavy metals in the aquatic environment. © 2009 Elsevier B.V. All rights reserved.

Agency: European Commission | Branch: FP7 | Program: CP-IP-SICA | Phase: ENV.2010.4.1.3-2 | Award Amount: 9.15M | Year: 2010

The overall goal of the proposed project is to develop a coordinated global observation system for mercury able to provide temporal and spatial distributions of mercury concentrations in ambient air and precipitation over land and over surface waters at different altitudes and latitudes around the world. This will then provide high quality data for the validation and application of regional and global scale atmospheric models, to give to governments, national and international organisations and stakeholders a firm basis for future policy development and implementation. Specific objectives of the proposed project are (a) to establish a Global Observation System for Mercury (GMOS) able to provide ambient concentrations and deposition fluxes of mercury species around the world, by combining observations from permanent ground-based stations, and from oceanographic and tropospheric measurement campaigns; (b) to validate regional and global scale atmospheric mercury modelling systems able to predict temporal variations and spatial distributions of atmospheric mercury entering to and re-emitted from terrestrial and aquatic receptors; (c) to evaluate and identify source-receptor relationships at country scale and their temporal trends for current and projected scenarios of mercury emissions from anthropogenic and natural sources; (d) to develop interoperable tools to allow the sharing of observational and models output data produced by GMOS. The overarching goal of GMOS is to support the achievement of goals set by the GEO / GEOSS, and specifically of the GEO Task HE-09-02d and contribute to the advancement of our scientific understanding in the nine Societal Benefit Areas (SBA) established in GEOSS. The proposed project will rely on the results and knowledge acquired in the framework of past EU projects (i.e., MAMCS, MOE, MERCYMS) and international programs (i.e., UNECE TF HTAP; UNEP F&T partnership area).

Ma L.-G.,Institute of geochemistry Chinese Academy of Science | Ma L.-G.,University of Chinese Academy of Sciences | Xiao B.-H.,Institute of geochemistry Chinese Academy of Science
Bulletin of Mineralogy Petrology and Geochemistry | Year: 2011

Extraction and fractionation of different humic substances from soil samples are key processes in the comprehensive study of soil humic substances. This paper carefully reviewed worldwide advance in extraction and fractionation of soil humic substances. Under guidance of the reference method recommended by the International Humic Substance Society (IHSS) , this paper discussed the experiment conditions, for example, extractant, dosage, and extracting cycles, and evaluated two fractionation techniques we set up in the experiments. It is suggested that high performance size exclusive chromatography ( HPSEC) and ultrafiltration are two of the state-of-art analytical methods in fractionating and characterizing humic substances in natural soils, and that, once being combined, they can provide profound information to better understand the chemical attributes and the molecular structures of soil humic substances.

Liu Y.,Institute of Geochemistry Chinese Academy of science | Wang X.-B.,Chengdu University of Technology | Wang Y.,Institute of Geochemistry Chinese Academy of science
Applied Geophysics | Year: 2013

To effectively minimize the electromagnetic field response in the total field solution, we propose a numerical modeling method for the two-dimensional (2D) timedomain transient electromagnetic secondary field of the line source based on the DuFort-Frankel finite-difference method. In the proposed method, we included the treatment of the earth-air boundary conductivity, calculated the normalized partial derivative of the induced electromotive force (Emf), and determined the forward time step. By extending upward the earth-air interface to the air grid nodes and the zero-value boundary conditions, not only we have a method that is more efficient but also simpler than the total field solution. We computed and analyzed the homogeneous half-space model and the flat layered model with high precision-the maximum relative error is less than 0.01% between our method and the analytical method-and the solution speed is roughly three times faster than the total-field solution. Lastly, we used the model of a thin body embedded in a homogeneous half-space at different delay times to depict the downward and upward spreading characteristics of the induced eddy current, and the physical interaction processes between the electromagnetic field and the underground low-resistivity body. © 2013 Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.

Zhang W.,Institute of Geochemistry Chinese Academy of science | Zhang W.,University of Chinese Academy of Sciences | Leng C.-B.,Institute of Geochemistry Chinese Academy of science | Zhang X.-C.,Institute of Geochemistry Chinese Academy of science | And 4 more authors.
Lithos | Year: 2016

The Seleteguole Cu-Mo deposit in Jinghe County, Xinjiang is tectonically located on the northern margin of the Northwestern Tianshan. Three major intrusions including biotite granite, diorite porphyry and quartz diorite porphyry have been identified. The biotite granite, with a zircon U-Pb age of 307 ± 3 Ma, intruded carbonates and clastic rocks of the Middle Carboniferous Dongtujin Formation. The younger diorite porphyry and quartz diorite porphyry, with an identical zircon U-Pb age of 302 ± 3 Ma, locally intruded the biotite granite; where the granite in contact with the two porphyries were characterized by phyllic alteration. The mineralogical and geochemical characteristics indicate that all granitoids in Seleteguole belong to calc-alkaline I-type. These granitoids are enriched in LILE relative to HFSE with negative anomalies of Nb, P and Ti, typical of arc-related rocks. All three granitoids have positive zircon εHf(t) values, low Mg# ratios (34-39), and low Cr (<60 ppm) and Ni (<15 ppm) contents, suggesting that their parental magmas could be derived from juvenile lower crust that has probably originated from cooling of mantle-derived magmas as a result of the subduction of Paleo-Junggar Ocean beneath the Yili Block. Subducted sediments were involved in the source of the granitoids in Seleteguole. Compared to biotite granite, diorite porphyry and quartz diorite porphyry have higher Th/La ratios but lower zircon εHf(t) values, indicating that more subducted sediments contributed in the latter two. The regional geological and geochemical characteristics of the Late Carboniferous igneous rocks in the Northwestern Tianshan show that Late Carboniferous I-type granitoids, with juvenile Sr-Nd-(Hf) isotopic signatures, formed in a continent-marginal arc setting as a result of the subduction of Paleo-Junggar Ocean beneath the Yili Block. In combination with the compositions of the Early Permian granitoids in the region, we suggest that the tectonic setting of the Northwestern Tianshan transformed from a continental arc to an intracontinental extension setting at the Carboniferous-Permian boundary (ca. 300 Ma). © 2016 Elsevier B.V.

Lian B.,Institute of Geochemistry Chinese Academy of science
Bulletin of Mineralogy Petrology and Geochemistry | Year: 2010

Carbonate rock weathering has received closely attention of scientists for a long time since the material origin of soils in Karst areas is still being disputed with no many agreements. Summarized previous studies about soil genesis from weathering of carbonate rocks as well as our own research progress we proposed that weathering of carbonate rock by rock microbe is an important way to form Karst soil. Microorganisms living in carbonate rocks need to uptake nutrients from the rock and to release complicated organic ligands into the rock, these processes will accelerate decomposition of the rocks; microorganisms can fix C and N from atmosphere and capture other exotic matters, like rain water, aerosol, dust and even soil particles, to provide origin materials of soil. In other words, the rock microorganisms play an important and un-substitute role in the formation of Karst soil from carbonate rock weathering during the long history of geological evolution.

Sun G.,Wuhan University | Sun G.,Hei Longjiang Institute of Geological Survey | Sun G.,Northeast Petroleum University | Li Z.,Institute of Geochemistry Chinese Academy of science | And 4 more authors.
Atmospheric Environment | Year: 2013

Mercury (Hg) contamination in urban area is a hot issue in environmental research. In this study, the distribution, sources and health risk of Hg in dust from 69 kindergartens in Wuhan, China, were investigated. In comparison with most other cities, the concentrations of total mercury (THg) and methylmercury (MeHg) were significantly elevated, ranging from 0.15 to 10.59mgkg-1 and from 0.64 to 3.88μgkg-1, respectively. Among the five different urban areas, the educational area had the highest concentrations of THg and MeHg. The GIS mapping was used to identify the hot-spot areas and assess the potential pollution sources of Hg. The emissions of coal-power plants and coking plants were the main sources of THg in the dust, whereas the contributions of municipal solid waste (MSW) landfills and iron and steel smelting related industries were not significant. However, the emission of MSW landfills was considered to be an important source of MeHg in the studied area. The result of health risk assessment indicated that there was a high adverse health effect of the kindergarten dust in terms of Hg contamination on the children living in the educational area (Hazard index (HI)=6.89). © 2013 Elsevier Ltd.

Bi W.,Urumqi Jinwei Map character Information And Science and Technology Co. | Liu Y.,Institute of Geochemistry Chinese Academy of science
Wutan Huatan Jisuan Jishu | Year: 2014

In order to easily model topography in field work, on the basis of predecessors' achievements, the arbitrary quadrilateral element grid was used in the finite element method (FEM), and the electromagnetic field of models were designed to bilinear variation within each quadrilateral element in our numeric modeling. We deduced the specific formula to calculate the unit coefficient matrix by Gaussian numerical integral and the expression of the auxiliary field when using arbitrary quadratic element. Model calculation shows that the mean square error between the simulation results with the analytical solution is less than 1 percent, and the results of terrain model is consistent with the one of other scholar's. Through modeling of two ramp terrain modes with different pitch, comparing and analyzing the effect of the apparent resistivity and the phase. Due to the use of arbitrary quadrilateral element grid, the difficulty of programing was reduced, forward modeling can be more easily adapt to the topography variation.

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