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Paleoclimatic application of spectral parameters to the eolian red clay of the Jianzha Basin,northeastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1952-1966页

作者： Chaofeng FU Ju’e TIAN Xinwen XU Yougui SONG Jun ZUO Feng WANG Lin CHEN Pengfei LI Xiaoke QIANG The School of Earth Science and Resources Chang’an UniversityXi’an 710054China state key laboratory of loess and quaternary geology Institute of Earth and EnvironmentCASXi’an 710061China College of Urban and Environmental Science Northwest UniversityXi’an 710069China CAS Center for Excellence in quaternary Science and Global Change Xi’an 710061China

Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and sediments.We measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic changes.We obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic parameters.The results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ^(18)O record.The results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital timescales.SWIR parameters,such as AS1400,D1400/D1900 and D1900(where AS represents the asymmetry of the absorption peaks around1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering intensity.The spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at~8.5 Ma and global climatic cooling at~7.2 Ma,and thus they are applicable as both regional and global paleoenvironmental indicators.

关键词： Visible/near-infrared spectroscopy Short-wave infrared spectroscopy Paleoclimatic indicators Red clay Tibetan Plateau

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Insights into the provenance implication of leaf wax n-alkanes along the lower Yellow River

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Science China Earth Sciences 2024年第6期67卷 2001-2018页

作者： Liang ZHANG Jinzhao LIU Chong JIANG Fei ZHANG Zhisheng AN School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710054China state key laboratory of loess and quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China National Observation and Research Station of Earth Critical Zone on the loess Plateau of Shaanxi Xi’an 710061China

Serving as one of the largest rivers in terms of both sediment and organic carbon transport fluxes in the world,the Yellow River plays a crucial role in regional biogeochemical process as well as in the global carbon cycle.However,although a large number of studies have been carried out on the flux,composition,source and seasonal variation of total particulate organic carbon in the Yellow River so far,studies on molecular biomarkers at different spatial and temporal scales are still scarce.In this study,we focus on the molecular and hydrogen isotopic properties of leaf wax n-alkanes among different types of samples which obtained from different seasons(flood vs.non-flood)along the lower Yellow River.The molecular distribution of n-alkanes show that the riparian topsoils are subject to inputs from the overlying vegetation,while the suspended sediments from the flood season are characterized by the mixing of soil materials which originate from various stratigraphy with different ages on the Chinese loess Plateau.Due to the contrasting hydrodynamic conditions,the n-alkanes in suspended sediments also show distinct molecular composition between flood and non-flood seasons.Additionally,considering the effect of climatic factors,the proportion of monocots in flood-season suspended sediments is calculated from a semi-quantitative perspective using δ^(2)H_(wax).Our findings may bring to light new considerations for the interpretation of leaf wax proxies in studies of organic matter sources of Yellow River.

关键词： Molecular distribution Hydrogen isotopic composition Leaf wax n-alkanes Suspended sediments Lower Yellow River

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Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,China:Abundance,functional groups,and light absorption

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Particuology 2024年第1期84卷 281-289页

作者： Xueting Yang Shasha Huang Dan Li Hongmei Xu Yaling Zeng Liu Yang Diwei Wang Ningning Zhang Junji Cao Zhenxing Shen Department of Environmental Science and Engineering Xi'an Jiaotong UniversityXi'an710049China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China state key laboratory of loess and quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710049China

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate change.In this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer 2020.Neutral HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared spectra.Of the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in summer.Moreover,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in winter.The results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in summer.HULIS-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

关键词： Humic-like substances(HULIS) Aromaticity Fourier-transform infrared(FTIR) spectroscopy Light absorbance

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Land use effects on the dynamics of soil C,N and microbes in the water-wind erosion crisscross region of the northern loess Plateau,China

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Pedosphere 2024年第1期34卷 181-190页

作者： Yi WANG Chunyue LI Shunjin HU state key laboratory of loess and quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China state key laboratory of Soil Erosion and Dryland Farming on the loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China Department of Entomology&Plant Pathology North Carolina State UniversityRaleigh 27695USA

The water-wind erosion crisscross region of the northern loess Plateau in China is under constant pressure from severe erosion due to its windy and dry climate and intensive human activities. Identifying sustainable land use patterns is key to maintaining ecosystem sustainability in the area. Our aim was to appraise the impacts of different land use regimes on the dynamics of soil total organic C(TOC), total N(TN), and microbes in a typical watershed in the northern loess Plateau to identify suitable land use types that can maintain soil fertility and sustainability. A field experiment was performed in Liudaogou watershed in Shenmu City, Shaanxi Province, China, where the dynamics of soil TOC and TN, microbial biomass C and N, microbial respiration, and net N mineralization in six typical land use types, dam land, rainfed slope land, deciduous broadleaf forest, evergreen coniferous forest, shrubland, and grassland,were measured in three different growing seasons. Land use type and season significantly affected TOC, TN, and the dynamics of microbial biomass and activity. As the most anthropogenically disturbed land use pattern, dam land was an optimal land use pattern for TOC sequestration due to its higher TOC and TN, but lower microbial activity. Soil TOC, TN, and microbial properties demonstrated a decreasing trend after natural grassland was converted to shrubland,forest, and rainfed slope land. Shrubland with exotic N-fixing Korshinsk peashrub(Caragana korshinskii Kom.) can maintain TOC, TN, and microbial properties similar to those in grassland. Soil TOC, NH_(4+)^(-)N, TN, moisture, and extractable C were the principal indexes for soil microbial biomass and activity and explained 88.90% of the total variance. Thus, grassland was the optimal land use pattern in the water-wind erosion crisscross region of the northern loess Plateau to maintain ecosystem stability and sustainability.

关键词： grassland microbial activity microbial biomass total organic C total N watershed

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Molecular compositions and sources of organic aerosols at a rural site on the Guanzhong Plain,Northwest China:The importance of biomass burning

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Particuology 2024年第6期89卷 44-56页

作者： Yali Liu Minxia Shen Haijiao Liu Wenting Dai Weining Qi Yifan Zhang Lu Li Yue Cao Xin Wang Xiao Guo Yingkun Jiang Jianjun Li state key laboratory of loess and quaternary geology Key Lab of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain ShaanxiChina

The concentration of PM_(2.5)has considerably reduced in recent years,but remains relatively high in China.In particular,the increasing contribution of organic compounds to PM_(2.5)generates popular pressure for further reductions,resulting in an urgent need to study organic aerosol(OA).To investigate the molecular composition and source contribution of OA in the rural area of the Guanzhong Plain,Northwest China,PM_(2.5)samples were collected during 3–23 August 2016 and 5–20 January 2017 and studied for more than 100 organic tracer compounds.The mean concentration of total measured organic compounds is 662±296 ng/m^(3)in summer and 3258±1925 ng/m^(3)in winter.Levoglucosan is the most abundant single compound found throughout the sampling period,which is a crucial tracer for biomass burning emissions,preliminary suggesting that biomass burning is an essential source of OA.In summer,organic compounds such as lipid compounds,sugar compounds,and polycyclic aromatic hydrocarbons(PAHs),more come from higher plants,wood burning,vehicle exhausts,plastic waste,and other direct emission sources.Oxygenated PAHs(OPAHs),nitrophenols,and phthalic acids more come from the atmosphere through the oxidation reaction of aromatic precursors,especially photochemical oxidation.However,in winter,most of the increases in concentrations of organic compounds are attributed to biomass burning.The analysis of a haze event(14–19 January 2017)during the winter sampling period shows that the increases in the concentration of organic compounds are unaccompanied by strong secondary formation under lower relative humidity(49.1%±13.5%).The main reason for the growth of OA in this haze event is the accumulation of primary OA(POA).The source apportionment by the positive matrix factorization(PMF)model shows that biomass burning(37.1%)is the primary source of OA in the rural regions of the Guanzhong Plain,especially in winter(40.6%).The contribution of secondary formation decreases from 26.0%in summer to 16.9%in winter,and the contribution of fossil

关键词： Organic aerosol Molecular composition Seasonal variation Source apportionment Guanzhong Plain

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Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material

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National Science Review 2024年第2期11卷 177-187页

作者： Xianjin Shi Yu Huang Ran Long Zhenyu Wang Liqin Wang Junji Cao Gangqiang Zhu Yujie Xiong state key laboratory of loess and quaternary geology(SKLLQG) Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of Sciences Center of Excellence in quaternary Science and Global Change Chinese Academy of Sciences University of Chinese Academy of Sciences Hefei National Research Center for Physical Sciences at the Microscale School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Institute of Atmospheric Physics Chinese Academy of Sciences School of Physics and Information Technology Shaanxi Normal University

Solar-driven CO2conversion into hydrocarbon fuels is a sustainable approach to synchronously alleviating the energy crisis and achieving net CO2emissions.However,the dependence of the conversion process on solar illumination hinders its practical application due to the intermittent availability of sunlight at night and on cloudy or rainy days.Here,we report a model material of Pt-loaded hexagonal tungsten trioxide（Pt/h-WO3） for decoupling light and dark reaction processes,demonstrating the sustainable CO2conversion under dark conditions for the first time.In such a material system,hydrogen atoms can be produced by photocatalytic water splitting under solar illumination,stored together with electrons in the h-WO3through the transition of W6+to W5+and spontaneously released to trigger catalytic CO2reduction under dark conditions.Furthermore,we demonstrate using natural light that CH4production can persist at night and on rainy days,proving the accomplishment of all-weather CO2conversion via a sustainable way.

关键词： sustainable CO2 utilization artificial photosynthesis all-weather application charge storage

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Nitrogen and phosphorus fertilization leads to soil arbuscular mycorrhizal fungal diversity changes and rainfed crop yield increase on the loess Plateau of China:A 37-year study

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Pedosphere 2024年第2期34卷 328-338页

作者： Yi WANG Wenting ZHANG Chunyue LI Shun CHANG Yu MIAO Qianxue LI Zhaoyang KOU Tinghui DANG state key laboratory of loess and quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China

More than 80%of plants form mutualistic symbiotic relationships with arbuscular mycorrhizal fungi(AMF),and the application of fertilizers,such as nitrogen(N)and phosphorus(P)fertilizers,is a common agricultural management practice to improve crop yield and quality.However,the potential effects of long-term N and P fertilization on the AMF community in the rainfed agricultural system of the loess Plateau of China are still not well understood.In this study,a long-term field experiment was conducted based on orthogonal design,with three N levels(0,90,and 180 kg ha^(-1)year^(-1))and three P levels(0,90,and 180 kg ha^(-1)year^(-1))for wheat fertilization.Changes in AMF community and correlations between AMF community composition,soil environmental factors,and wheat yield component traits were analyzed using traditional biochemical methods and high-throughput sequencing technology.The results showed that long-term N and P addition had a significant effect on the AMF community structure and composition.Nitrogen application alone significantly reduced the richness and diversity of AMF community,whereas the combined application of N and P significantly increased the richness and diversity of AMF community.The AMF community was driven mainly by soil available P,total P,and pH.There was a significant positive correlation between Glomus abundance and wheat yield and a significant negative correlation between Paraglomus abundance and wheat yield.Long-term N and P addition directly increased crop yield and affected yield indirectly by influencing soil chemical properties and the AMF community.Combined application of N and P both at90 kg ha^(-1)year^(-1)could improve the ecological and physiological functions of the AMF community and benefit the sustainable development of rainfed agriculture.

关键词： Glomus long-term fertilization microbial community Paraglomus rainfed agriculture wheat

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Recent progress of MgO-based materials in CO_(2) adsorption and conversion:Modification methods,reaction condition,and CO_(2) hydrogenation

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Chinese Chemical Letters 2024年第5期35卷 57-65页

作者： Zixuan Zhu Xianjin Shi Yongfang Rao Yu Huang key laboratory of Aerosol Chemistry&Physics State Key Laboratory of Loess and Quaternary Geology(SKLLQG)Institute of Earth EnvironmentChinese Academy of Sciences(CAS)Xi’an 710061China Center for Excellence in quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China Department of Environmental Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

Integrated CO_(2) capture and conversion of(ICCC)is one of the most effective solutions to reduce anthropogenic CO_(2) emissions,which has attracted extensive public attention.Dual functional materials(DFMs),including adsorbent and catalyst,are the key components to achieve ICCC.Magnesium oxide(MgO)is an ideal adsorbent for ICCC,since it is characterized by high theoretical adsorption capacity,low cost,low energy consumption and extensive sources.It can also be used as DFMs in combination with the Ni catalysts.MgO not only can act as an adsorbent in DFMs but also enhance the catalytic performance of Ni.This review summarizes the advantages and modification methods of MgO as adsorbent and the influence of its adsorption conditions on the adsorption performance.Moreover,the important role of MgO in facilitating the catalytic conversion of CO_(2) is highlighted.Future research focuses are proposed for the development of MgO based DFMs with high adsorption capacity,high stability,conversion,and selectivity as well as low cost and energy consumption.

关键词： CO_(2) ICCC MgO Adsorption Conversion

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Mobility of rhenium and selenium during chemical weathering and their implication for petrogenic organic carbon oxidation

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Science China Earth Sciences 2024年第3期67卷 740-750页

作者： Yuhong ZHANG Jin WANG Yuanxin QU Chao ZHU Zhangdong JIN state key laboratory of loess and quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710049China

The oxidative weathering of petrogenic organic carbon(OC_(petro)) is an important source of carbon dioxide(CO_(2)) into the atmosphere on geological timescales and significantly influences the carbon cycle and global climate change. However, at present, a robust proxy to assess OC_(petro)oxidation is lacking. Riverine rhenium(Re) has emerged as a potential proxy to trace OC_(petro)oxidation, but little is known about Re sources and its relationship with OC_(petro)oxidation. To better understand the robustness of this proxy, we analyzed a shale weathering profile from the early Cambrian Shuijingtuo Formation in Chengkou County, Chongqing City, to address the mobility of Re and selenium(Se) and their relationship with the oxidation of OC_(petro)by analyses of the elemental variation and sequential extraction. The results showed that the chemical index of alteration(CIA)increases from the fresh bedrock to the weathered sections, indicating enhanced weathering intensity. Based on the sequential extraction and mass transfer coefficients(τ), Re and Se mainly exist in the organic phase of shale and are paired lost with OC_(petro) during weathering, with no obvious correlation with sulfide minerals. Furthermore, the different proportions of Re and Se loss with OC_(petro) loss can be attributed to their different geochemical behaviors during weathering. Our study supports Re as a robust proxy to trace OC_(petro) oxidation, whereas Se is the potential one. In the future, combined studies on various sedimentary rock profiles with catchment basins are needed to determine the sources of riverine Re and Se and their relationships with OC_(petro) oxidation.

关键词： Rhenium and selenium Shale Mobility OC_(petro) Chemical weathering

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Promoted surface charge density from interlayer Zn–N_(4) configuration in carbon nitride for enhanced CO_(2) photoreduction

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Nano Research 2024年第4期17卷 2400-2409页

作者： Xianjin Shi Yu Huang Gangqiang Zhu Wei Peng Meijuan Chen state key laboratory of loess and quaternary geology(SKLLQG) Key Laboratory of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Center of Excellence in quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China

The solar-driven reduction of CO_(2) into valuable products is a promising method to alleviate global environmental problems and energy crises.However,the low surface charge density limits the photocatalytic conversion performance of CO_(2).Herein,a polymeric carbon nitride(PCN)photocatalyst with Zn single atoms(Zn1/CN)was designed and synthesized for CO_(2) photoreduction.The results of the CO_(2) photoreduction studies show that the CO and CH_(4) yields of Zn1/CN increased fivefold,reaching 76.9 and 22.9μmol/(g·h),respectively,in contrast to the unmodified PCN.Ar+plasma-etched X-ray photoelectron spectroscopy and synchrotron radiation-based X-ray absorption fine structure results reveal that Zn single atom is mainly present in the interlayer space of PCN in the Zn–N_(4) configuration.Photoelectrochemical characterizations indicate that the interlayer Zn–N_(4) configuration can amplify light absorption and establish an interlayer charge transfer channel.Light-assisted Kelvin probe force microscopy confirms that more photogenerated electrons are delivered to the catalyst surface through interlayer Zn–N_(4) configuration,which increases its surface charge density.Further,in-situ infrared spectroscopy combined with density functional theory calculation reveals that promoted surface charge density accelerates key intermediates(*COOH)conversion,thus achieving efficient CO_(2) conversion.This work elucidates the role of internal single atoms in catalytic surface reactions,which provides important implications for the design of single-atom catalysts.

关键词： single-atom catalysts photocatalytic CO_(2)reduction interlayer modification charge transfer dynamics surface charge density

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