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Journal of Geographical Sciences 2008年第3期18卷 341-352页

作者： CHEN Yingyong LI Xusheng HAN Zhiyong YANG Shouye WANG Yongbo YANG Dayuan School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China state key laboratory of loess and Quaternary geology Institute of Earth Environment CAS Xi＇an 710075 China state key laboratory of Marine geology Tongji University Shanghai 200092 China

The chemical weathering intensity and element migration features of the Xiashu loess profile in Zhenjiang are studied in this paper.（1）The Xiashu loess profile underwent moderate chemical *** seems that the precipitation is a more important factor than the temperature in controlling the process of the chemical weathering.（2）The major elements such as Si,K,Na,Ca,Mg,Mn and P were migrated and leached,while the elements Fe and Ti were slightly *** migration features of the major elements reveal that the Xiashu loess finished the primary process of chemical weathering characterized by leaching of Ca and Na,and almost reached the secondary process characterized by leaching of *** the elements Sr and Ga,other trace elements such as Th,Ba,Cu,Zn,Co,Ni,Cr and V were *** might be caused by both the biogeochemical process and the adsorption of trace elements by clay mineral and organic materials.（3）The difference of element migration down the Xiashu loess profile reveals that the climate was warm and wet at the early-middle stage of the middle *** the end of the middle Pleistocene,it became dry and *** the early stage of the Late Pleistocene,the paleoclimate became warm and wet *** a whole,the paleoclimate generally became drier and cooler in this region from the beginning of the middle Pleistocene.

关键词： Xiashu loess chemical weathering element migration Zhenjiang

One-step synthesis of N-doped metal/biochar composite using NH_3-ambiance pyrolysis for efficient degradation and mineralization of Methylene Blue

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Journal of Environmental Sciences 2019年第4期31卷 29-41页

作者： Md Manik Mian Guijian Liu Balal Yousaf Biao Fu Rafay Ahmed Qumber Abbas Mehr Ahmed Mujtaba Munir Liu Ruijia CAS key laboratory of Crust-Mantle Materials and the Environments School of Earth and Space SciencesUniversity of Science and Technology of China state key laboratory of loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of Sciences

A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles(NPs)were produced through single-step pyrolysis of FeCl_3–Ti(OBu)_4 laden agar biomass under NH_3 *** physiochemical properties of composites were characterized *** has found that heating temperature and N-doping through NH_3-ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of *** catalytic activities of composites were measured by degradation of Methylene Blue(MB)in the presence or absence of H_2O_2 and visible-light *** best catalyst(N–TiO_2–Fe_3O_4-biochar)exhibits rapid and high MB removal competency(99.99%)via synergism of adsorption,photodegradation,and Fenton-like *** production of O_2U^-and UOH radicles performs MB degradation and mineralization,confirmed by scavenging experiments and degradation product *** local trap state Ti^(3+),Fe_3O_4,and N-carbon of the catalyst acted as active *** has suggested that the Ti^(3+)and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like ***,the catalyst is highly stable,collectible,and recyclable up to 5 cycles with high MB degradation *** work provides a new insight into the synthesis of highly visible-light sensitized biocharsupported photocatalyst through NH_3-ambiance pyrolysis of NPs-laden biomass.

关键词： Biochar-supported photocatalyst N–TiO2–Fe3O4-biochar NH3-ambiance pyrolysis Methylene Blue Photocatalysis

Fingerprinting hydrothermal fluids in porphyry Cu deposits using K and Mg isotopes

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Science China Earth Sciences 2020年第1期63卷 108-120页

作者： Weiqiang LI Shugao ZHAO Xiaomin WANG Shilei LI Guoguang WANG Tao YANG Zhangdong JIN state key laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210046China state key laboratory of loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China

In this study, we performed an integrated investigation of K and Mg isotopes in hydrothermally altered rocks from the giant Dexing porphyry Cu deposit in China. Both the altered porphyry intrusion and the surrounding wall rocks exhibit large variations in K and Mg isotope compositions, with δ41K values ranging between-1.02‰ and 0.38‰, and δ26Mg values ranging between-0.49‰ and 0.32‰. The δ41K and δ26Mg values of the majority of altered samples are higher than the isotopic baseline values for upper continental crust. We attribute the general increase in δ41 K and δ26Mg in altered rocks to hydrothermal alteration,which caused preferential incorporation of heavy K and Mg isotopes in alteration products, particularly phyllosilicates. However,a few altered samples show anomalously low δ41K and δ26Mg values. The δ41K and δ26Mg values do not correlate with K and Mg concentrations, or mineralogy of altered samples. The variable K-Mg isotope data likely reflect fluids of different physicalchemical properties, or different isotopic compositions. Based on the combined K-Mg isotope data, at least three groups of hydrothermal fluids are distinguished from the Dexing porphyry deposit. Therefore, K-Mg isotopes are potentially a novel tracer for fingerprinting fluids in complex hydrothermal systems.

关键词： hydrothermal isotope alteration

Aerosol composition,sources,and secondary processing during autumn at a regional site in the Beijing-Tianjin-Hebei region

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Particuology 2023年第4期75卷 177-184页

作者： Yichen Wang Qiyuan Wang Jie Tian Yong Zhang Yunfei Wu Weikang Ran Renjian Zhang Junji Cao School of Public Policy and Administration Northwestern Polytechnical UniversityXi'an710129China key laboratory of Aerosol Chemistry and Physics state key laboratory of loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710061China CAS Center for Excellence in Quaternary Science and Global Change Xi'an710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing100029China Xianghe Observatoryof Whole Atmosphere Institute of Atmospheric PhysicsChinese Academy of SciencesXianghe CountyHebei Province065400China

Air pollution is serious during autumn in the Beijing-Tianjin-Hebei(BTH)region,but there are few studies that have utilized real-time observations and source apportionment of the autumn submicron aerosols in this *** this study,a quadrupole aerosol chemical speciation monitor(Q-ACSM)was deployed for the real-time measurement of the non-refractory compositions of submicron aerosols(NR-PM1)at a regional site(Xianghe)from October 3 to November 14,*** results showed that nitrate was the largest inorganic aerosol,and the oxygenated organic aerosol(OOA)was the largest organic aerosol in ***-like OA(HOA)was the largest organic aerosol When the NR-PM1 mass concentrations increased from the lowest to the highest bins,nitrate and biomass burning OA(BBOA)showed increasing trends in the suburban *** nitrate formation during the pollution epi-sodes resulted from both photochemical and aqueous *** reduce the particulate matter(PM2.5)concentrations and eliminate heavy pollution episodes,control measures should focus on reducing NO_(x),NH_(3),and volatile organic compound(VOCs)emissions.

关键词： Autumn Beijing-Tianjin-Hebei region Submicron aerosol Organic sources Control measures

Variations in chemical compositions of the eolian dust in Chinese loess Plateau over the past 2.5 Ma and chemical weathering in the Asian inland

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Science China Earth Sciences 2001年第5期44卷 403-413页

作者：陈骏安芷生刘连文季峻峰杨杰东陈旸 Institute of Surfacial Geochemistry State Key Laboratory of Mineral Deposit Research Department of Earth Sciences Nanjing University Nanjing China state key laboratory of loess and Quaternary geology Chinese Academy of Sciences Xi’an China

Major and trace elements as well as strontium isotopiccomposition have been analyzed on the acid-insoluble (AI) phase of the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemical composition of AI phase of loess and paleosols is distinctive to the average composition of upper continental crust (UCC), characterized by depletion of mobile elements Na, Ca and Sr. The distribution pattern of elements in AI phase reveals that initial dust, derived from a vast area of Asian inland, has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters (such as CIA values, Na/K, Rb/Sr and 87Sr/87Sr ratios) display a regular variation and evolution, reflecting that the chemical weathering in the source region of loess deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change.

关键词：灰尘来源区域捱过的大陆人酸的沥滤干旱全球冷却

Soil microbial respiration is regulated by stoichiometric imbalances: Evidence from a humidity gradient case

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Pedosphere 2023年第6期33卷 905-915页

作者： Jiwei LI Jiangbo XIE Jianzhao WU Yongxing CUI Lingbo DONG Yulin LIU Xuying HAI Yan LI Zhouping SHANGGUAN Kaibo WANG Changhui PENG Lei DENG state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau College of Soil and Water Conservation Science and Engineering(Institute of Soil and Water Conservation)Northwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China state key laboratory of Subtropical Silviculture Zhejiang A&F UniversityLin'an 311300China Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100871China University of Chinese Academy of Sciences Beijing 100049China state key laboratory of loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Center of CEF/ESCER Department of Biological ScienceUniversity of Quebec at MontrealMontreal H3C 3P8Canada

Humidity not only affects soil microbial respiration(SMR) directly, but, indirectly by regulating the availability of soil water and nutrients. However,the patterns of direct and indirect effects of humidity on SMR over large precipitation gradients remain unclear, limiting our understanding of the effects of precipitation changes on soil C cycle. Here, we investigated the relationships among humidity, soil nutrients, and SMR by identifying stoichiometric imbalances, microbial elemental homeostasis, and microbial C use efficiency along a precipitation gradient at a continental scale. The relationship between SMR and humidity index(HI) corresponded to a Richard’s curve with an inflection point threshold value of approximately 0.7. Soil microbial respiration increased with increasing humidity in drier areas(HI 0.7). Soil microbial communities regulated their enzyme production to maintain a strong stoichiometric homeostasis in drier areas;enzyme production, microbial biomass, and threshold elemental ratios were non-homeostatic under P limitation in wetter areas, which further contributed to the increase in SMR. Our results identified a moisture constraint on SMR in drier areas and highlighted the importance of nutrient(especially for P) limitations induced by humidity in regulating SMR in wetter areas. Understanding the modulation of SMR via soil enzyme activity may improve the prediction of soil C budget under future global climate change.

关键词： carbon use efficiency ecological stoichiometry microorganisms nutrient limitations precipitation soil enzyme activities stoichiometric homeostasis

Surrogate atmospheric dust particles generated from dune soils in laboratory: Comparison with field measurement

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Particuology 2023年第1期72卷 29-36页

作者： Feng Wu Na Song Tafeng Hu Steven Sai Hang Ho Junji Cao Daizhou Zhang state key laboratory of loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China key laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing100029China Faculty of Environmental and Symbiotic Sciences Prefectural University of KumamotoKumamoto 862-8502Japan Division of Atmospheric Sciences Desert Research InstituteRenoNV 89512United States

Desert dust strongly influences the climate and the environment by altering the radiation budget, participating in atmospheric chemical reactions, and engaging the biogeochemical cycle. Studying its impacts requires knowledge of the physical and chemical properties of the original particles from the source origin. Unfortunately, the field collection of atmospheric samples in the desert is impractical. Fine surface soil is thus considered an alternative material from which to obtain the information applicable to dust particles from the desert soil. In this study, a laboratory system was set up to generate dust particles with simulated natural wind erosion processes from surface soils or directly from desert surfaces. Surface soils and field dust were simultaneously collected during a local blowing dust event. The comparison between the laboratory-generated dust and the field dust showed a consistent trend in particle size distribution and chemical composition. The chemical compositions were found to have explainable differences with the Certified Reference Materials for Asian dust (CJ-2). The laboratory-generated dust particles with the system could be applied as surrogates for soil-emitted dust in desert areas.

关键词： laboratory dust simulation system Asian dust Source profiles Particle sizes Chemical compositions

Hydrogen isotopic composition of plant leaf wax in response to soil moisture in an arid ecosystem of the northeast Qinghai-Tibetan Plateau, China

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Journal of Arid Land 2014年第5期6卷 592-600页

作者： Yuan YAO WeiGuo LIU School of Human Settlements and Civil Engineering Xi'an Jiaotong University state key laboratory of loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences

The hydrogen isotopic composition of plant leaf wax（δDwax） is used as an important tool for paleohydrologic reconstruction. However, the understanding of the relative importance of environmental and biological factors in determining δDwax values still remains incomplete. To identify the effects of soil moisture and plant physiology on δDwax values in an arid ecosystem, and to explore the implication of these values for paleoclimatic reconstruction, we measured δD values of soil water（δDwater） and δDwax values in surface soils along two distance transects extending from the lakeshore to wetland to dryland around Lake Qinghai and Lake Gahai on the northeast Qinghai-Tibetan Plateau. The results showed that the δDwater values were negatively correlated with soil water content（SWC）（R^2=0.9166）, and ranged from –67‰ to –46‰ with changes in SWC from 6.2% to 42.1% in the arid areas of the Gangcha（GCh） and Gahai（GH） transects. This indicated that evaporative D-enrichment in soil water was sensitive to soil moisture in an arid ecosystem. Although the shift from grasses to shrubs with increasing aridity occurred in the arid area of the GH transect, the δDwax values in surface soils from the arid areas of the two transects still showed a negative correlation with SWC（R^2=0.6835）, which may be due to the controls of primary evaporative D-enrichment in the soil water and additional transpirational D-enrichment in the leaf water on the δDwaxvalues. Our preliminary research suggested that δDwax values can potentially be applied as a paleo-humidity indicator on the northeast Qinghai-Tibetan Plateau.

关键词： hydrogen isotope D-enrichment soil water content northeast Qinghai-Tibetan Plateau

Distributions and hydrogen isotopic compositions of plant leaf wax from Orinus kokonorica along a general aridity gradient around Lake Qinghai, China

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Chinese Journal Of Geochemistry 2014年第3期33卷 236-243页

作者： YAO Yuan LIU Weiguo School of Human Settlements and Civil Engineering Xi'an Jiaotong University state key laboratory of loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences

To quantitatively analyze the response of distributions and hydrogen isotopic compositions(δD) of plant leaf wax to moisture, and to better understand their implications for paleoclimatic reconstruction, we measured average chain length(ACL) and δD values of n-alkanes and n-fatty acids(n-FAs) from Orinus kokonorica, a typical and representative plant in Lake Qinghai area, along a distance transect extending from lakeshore to wetland to dryland in the arid ecosystem. The results showed that the ACL values of n-alkanes and n-FAs were negatively correlated with soil water content(SWC) with R2=0.593 and R2=0.924, respectively. This is as a result of plant's response to water loss with more abundance in long-chain n-alkyl lipids under increasing aridity by analyzing relationships between the molecular ratios of long-chain n-alkyl lipids(n-alkanes and n-FAs) from O. kokonorica and SWC. The δD values of C29 n-alkane and C28 n-FA were also negatively correlated with SWC with R2=0.778 and R2=0.760, respectively, which may due to enhanced D-enrichment in leaf water by evapotranspiration(soil water evaporation and leaf water transpiration) with increasing aridity. Our results demonstrated that moisture exerts a significant control on the ACL and δD values from O. kokonorica in an arid ecosystem. This preliminary study on a modern single plant(O. kokonorica) sets a foundation for comprehending these values as quantitative proxies for paleo-humidity reconstruction.

关键词：同位素组成青海湖地区植物叶干旱土壤水分蒸发访问控制列表正构烷烃梯度

A comparative study of n-alkane biomarker and pollen records: an example from southern China

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Chinese Science Bulletin 2009年第6期54卷 1065-1072页

作者： ZHENG YanHong ZHOU WeiJian XIE ShuCheng YU XueFeng state key laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China state key laboratory of loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China key laboratory of Biogeology and Environment geology of Ministry of Education China University of Geosciences Wuhan 430074 China

We report the results of a comparative study of n-alkane biomarkers and pollens in lacustrine and peat deposits at Dingnan, Jiangxi Province in southern China, and discuss the likely causes for the dis-crepancy in the interpretations of the n-alkane biomarker and pollen records in terms of climate and vegetation change. The results show that past changes in climate and vegetation revealed by the n-alkane record are not always consistent with the pollen assemblage record in the whole section. Biomarkers do not permit direct identification of the plant family and/or genus and mainly record compositions of local plant remains, while pollens mainly reflect the regional vegetation change. Bio-markers and pollen records complement each other, providing a better picture of local and regional environments. Furthermore, biomarkers are more sensitive than pollen to climatic and vegetational change. Several climatic events are clearly identified by the n-alkane biomarker proxies, such as C31/(C27+C29+C 31) ratio and can be correlated to the North Atlantic Heinrich event, B/A, YD and two dry-cool events during the early Holocene such as the periods of 9850 to 9585 cal a B.P. and 8590 to 7920 cal a B.P. These events are consistent with those found in the surrounding regions, suggesting that the regional climate was coupled with global-scale abrupt climatic events. Our results suggest that biomarker and pollen data can record the more detailed climate and vegetation information, thus im-proving the resolution and precision of vegetation and climate reconstruction.

关键词：烷烃生物标志物花粉记录华南地区植被变化气候条件个例气候事件孢粉组合