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1Prediction of carbon exchanges between China terrestrial ecosystem and atmosphere in 21st century显示文摘The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.JI JinJun HUANG Mei LI KeRang 2008Science China Earth Sciences2008,51,6:48
2Land use changes and their relations with carbon cycles over the past 300 a in China显示文摘Land use and land cover in China have changed greatly during the past 300 a, indicated by the rapid abrupt decrease of forest land area and the rapid increase of cropland area, which can affect terrestrial carbon cycle greatly. The first-hand materials are used to analyze main characteristics for land use and land cover changes in China during the study period. The following conclusions can be drawn from this study. The cropland area in China kept increasing from 60.78×106 hm2 in 1661 to 96.09×106 hm2 in 1998. Correspondingly, the forest land area decreased from 248.13×106 hm2 in 1700 to 109.01×106 hm2 in 1949. Affected by such changes, the terrestrial ecosystem carbon storage decreased in the mean time. Car-bon lost from land use and land cover changes mainly consist of the loss from vegetation biomass and soil. In the past 300 a, about 3.70 PgC was lost from vegetation biomass, and emissions from soil ranged from 0.80 to 5.84 PgC. The moderate evaluation of soil losses was 2.48 PgC. The total loss from vegetation and soil was between 4.50 and 9.54 PgC. The moderate and optimum evaluation was 6.18 PgC. Such carbon losses distribution varied spatially from region to region. Carbon lost more significantly in Northeast China and Southwest China than in other regions, because losses of forest land in these two regions were far greater than in the other regions during the past 300 a. And losses of carbon in the other regions were also definite, such as Inner Mongolia, the western part of South China, the Xinjiang Uygur Autonomous Region, and the Qinghai-Tibet Plateau. But the carbon lost very little from the traditional agricultural regions in China, such as North China and East China. Studies on the relationship between land use and land cover change and carbon cycle in China show that the land use activities, especially those related to agriculture and forest management, began to affect terrestrial carbon storage positively in recent years.GE QuanSheng DAI JunHu HE FanNeng PAN Yuan WANG MengMai 2008Science China Earth Sciences2008,51,6:30
3Effects of sunspot cycle length and CO_2 on air temperature along Qinghai-Xizang railway and air temperature's trend prediction显示文摘There are well coherences between annual averaged air temperatures at every meteorological station along the Qinghai-Xizang railway, and its 10-year moving average correlation coefficient is 0.92. Thus, the regional averaged annual mean temperature series along the Qinghai-Xizang railway (Trw) from 1935 to 2000 are constructed. The investigation is suggested that: Trw had significant responses to the 5-year lagged sunspot cycle length (SCL) and 15-year lagged concentration of atmospheric carbon dioxide (CO2), and the correlation coefficients between them are -0.76 (SCL) and 0.88 (CO2), respectively. The future SCL is predicted by the model of average generated function constructed with its main cycles of 76a, 93a, 108a, 205a and 275a. The result shows that the SCL would be becoming longer in the first half of the 21st century, and then it could be becoming shorter in the second half of the 21st century. Based on the natural change of SCL and the effect of double CO2 concentration, Trw in the 21st century is forecasted. It could warm up about 0.50℃ in the first half of the 21st century compared with the last decade of last century. The mean maximum air temperature could be likely about 0.20℃ in July and from 0.40℃ to 1.10℃ in January. The annual air temperature difference would likely reduce 0.3-1.00℃. The probability of above predictions ranges from 0.64 to 0.73.LI Dongliang, QUO Hui, WANG Wen & WEI LiCold & Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000, China Department of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China 2004Science China Earth Sciences2004,47,z1:28
4Characterizing the dynamics of soil organic carbon in grasslands on the Qinghai-Tibetan Plateau显示文摘Carbon dynamics of grasslands on the Qinghai-Tibetan Plateau may play an important role in regional and global carbon cycles. The CENTURY model (Version 4.5) is used to examine temporal and spatial variations of soil organic carbon (SOC) in grasslands on the Plateau for the period from 1960 to 2002. The model successfully simulates the dynamics of aboveground carbon and soil surface SOC at the soil depth of 0-20 cm and the simulated results agree well to the measurements. Examination of SOC for eight typical grasslands shows different patterns of temporal variation in different ecosystems in 1960-2002. The extent of temporal variation increases with the increase of SOC of ecosystem. SOC increases first and decreases quickly then during the period from 1990 to 2000. Spatially, SOC density obtained for the equilibrium condition declines gradually from the southeast to the northwest on the plateau and showed a high heterogeneity in the eastern plateau. The results suggest that (i) SOC den-sity in the alpine grasslands shows remarkable response to climate change during the 42 years, and (ii) the net carbon exchange rate between the alpine grassland ecosystems and the atmosphere increases from 1990 to 2000 as compared with that before 1990.ZHANG YongQiang TANG YanHong JIANG Jie YANG YongHui 2007Science China Earth Sciences2007,50,1:25
5The impacts of climate extremes on the terrestrial carbon cycle:A review显示文摘The increased frequency of climate extremes in recent years has profoundly affected terrestrial ecosystem functions and the welfare of human society. The carbon cycle is a key process of terrestrial ecosystem changes. Therefore, a better understanding and assessment of the impacts of climate extremes on the terrestrial carbon cycle could provide an important scientific basis to facilitate the mitigation and adaption of our society to climate change. In this paper, we systematically review the impacts of climate extremes(e.g. drought, extreme precipitation, extreme hot and extreme cold) on terrestrial ecosystems and their mechanisms. Existing studies have suggested that drought is one of the most important stressors on the terrestrial carbon sink, and that it can inhibit both ecosystem productivity and respiration. Because ecosystem productivity is usually more sensitive to drought than respiration, drought can significantly reduce the strength of terrestrial ecosystem carbon sinks and even turn them into carbon sources. Large inter-model variations have been found in the simulations of drought-induced changes in the carbon cycle, suggesting the existence of a large gap in current understanding of the mechanisms behind the responses of ecosystem carbon balance to drought, especially for tropical vegetation. The effects of extreme precipitation on the carbon cycle vary across different regions. In general, extreme precipitation enhances carbon accumulation in arid ecosystems, but restrains carbon sequestration in moist ecosystems. However, current knowledge on the indirect effects of extreme precipitation on the carbon cycle through regulating processes such as soil carbon lateral transportation and nutrient loss is still limited. This knowledge gap has caused large uncertainties in assessing the total carbon cycle impact of extreme precipitation. Extreme hot and extreme cold can affect the terrestrial carbon cycle through various ecosystem processes. Note that the severity of such climate extremes depends greatly on their timing, which needs to be investigated thoroughly in future studies. In light of current knowledge and gaps in the understanding of how extreme climates affect the terrestrial carbon cycle, we strongly recommend that future studies should place more attention on the long-term impacts and on the driving mechanisms at different time scales.Studies based on multi-source data, methods and across multiple spatial-temporal scales, are also necessary to better characterize the response of terrestrial ecosystems to climate extremes.Shilong PIAO Xinping ZHANG Anping CHEN Qiang LIU Xu LIAN Xuhui WANG Shushi PENG Xiuchen WU 2019Science China Earth Sciences2019,62,10:16
6SOME FEATURES OF CARBON CYCLES IN KARST SYSTEM AND THE IMPLICATION FOR EPIKARSTIFICATION —An Example of Yaji Karst Experimental Site in Guilin,China显示文摘The carbon pools of biomass,littering,and SOC wre studied with regards to carbon cycles in epikarst zone,taking an example of Yaji Karst Experiemnt Site in Guilin.This study was focused on SOC and its lability,SOC decomposition rate,CO 2 regime in the soils. 13 ctracing was used to persua the relation of bicarbonate in karst water to soil carbon.The results indicated sufficient carbon pool in SOC for the driveing CO 2 in the karst system.It was revealed that about 60percent of carbon in epi-karst springs resulted from SOC during spring and summer.Thus,the CO 2,driving the karstification,was not simply due to adsorption of atmospheric CO 2 but due to carbon transfer through the pathway of air-plant-soil-water.The driving force should not be overlooked for the epi-karst formation by soil as an interface of carbon environmental geochemistry.Pan Genxing Tao Yuxiang Shun Yuhua Teng Yongzhong Han Fushun College of Resource & Environment Science,Nanjing Agricultural Univ.,Nanjing, 210095 People’s Republic of China 1997Journal of Geographical Sciences1997,7,3:15
7Spatial patterns of terrestrial net ecosystem productivity in China during 1981―2000显示文摘As the third largest country in the world, China has highly variable environmental condition and eco- logical pattern in both space and time. Quantification of the spatial-temporal pattern and dynamic of terrestrial ecosystem carbon cycle in China is of great significance to regional and global carbon budget. In this study, we used a high-resolution climate database and an improved ecosystem process-based model to quantify spatio-temporal pattern and dynamic of net ecosystem productivity (NEP) in China and its responses to climate change during 1981 to 2000. The results showed that NEP increased from north to south and from northeast to southwest. Positive NEP (carbon sinks) occurred in the west of Southwest China, southeastern Tibet, Sanjiang Plain, Da Hinggan Mountains and the mid-west of North China. Negative NEP (carbon sources) were mainly found in Central China, the south of Southwest China, the north of Xinjiang, west and north of Inner Mongolia, and parts of North China. From the 1980s to 1990s, the increasing trend of NEP occurred in the middle of Northeast China Plain and the Loess Plateau and decreasing trends mainly occurred in a greater part of Central China. In the study period, natural forests had minimal carbon uptake, while grassland and shrublands accounted for nearly three fourths of the total carbon terrestrial uptakes in China during 1981―2000.TAO Bo1, CAO MingKui1, LI KeRang1, GU FengXue1, JI JinJun1,2, HUANG Mei1 & ZHANG LeiMing1 1 Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2 Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100101, China 2007Science China Earth Sciences2007,50,5:12
8Evolving paradigms in biological carbon cycling in the ocean显示文摘Carbon is a keystone element in global biogeochemical cycles.It plays a fundamental role in biotic andabiotic processes in the ocean,which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere.The interactions between abiotic and biogenic carbon(e.g.CO_2,Ca CO_3,organic matter)in the ocean are complex,and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon(RDOC)that equates to the magnitude of the pool of atmospheric CO_2.The concepts of the biological carbon pump(BCP)and the microbial loop(ML)shaped our understanding of the marine carbon cycle.The more recent concept of the microbial carbon pump(MCP),which is closely connected to those of the BCP and the ML,explicitly considers thesignificance of the ocean’s RDOC reservoir and provides a mechanistic framework for the exploration of its formation and persistence.Understanding of the MCP has benefited from advanced‘omics’and novel research in biological oceanography and microbial biogeochemistry.The need to predict the ocean’sresponse to climate change makes an integrative understanding of the BCP,ML and MCP a high priority.In this review,we summarize and discuss progress since the proposal of the MCP in 2010 and formulate research questions for the future.Chuanlun Zhang Hongyue Dang Farooq Azam Ronald Benner Louis Legendre Uta Passow Luca Polimene Carol Robinson Curtis A.Suttle Nianzhi Jiao 2018National Science Review2018,5,4:12
9Global significance of the carbon cycle in the karst dynamic system:evidence from geological and ecological processes显示文摘On the basis of proposing the existence of a karst carbon cycle and carbon sink at a watershed scale,this paper provides four pieces of evidence for;the integration of geology and ecology during the carbon cycle processes m the karst dynamic system,and estxmated the karst carbon sink effect using the methods of comparative monitoring of paired watersheds and the carbon stable isotope tracer technique.The results of the soil carbon cycle in Maocun,Guilin,showed that the soil carbon cycle in the karst area,the weathering and dissolution of carbonate rocks under the soil,resulted in a lower soil respiration of 25% in the karstoarea than in a non-karst area (sandstone and shale),and the carbon isotope results indicated that 13.46% of the heavy carbon of the hmestone is involved in the soil carbon cycle.The comparative monitoring results m paxred watersheds,suggesting that the HCO3 concentration m a karst spring is 10 times that of a rivulet in a non-karst area,while the concentration of inorganic carbon flux is 23.8 times.With both chemical stoichiometry and carbon stable isotopes,the proportion of carbon in karst springs derived from carbonate rocks was found to be 58.52% and 37.65% respectively.The comparison on carbon exchange and isotopes at the water-gas interface between the granite and carbonate rock basins in the Li River showed that the CO2 emission of the karst water is 10.92 times that of the allogenic water from the non-karst area,while the carbon isotope of HCO3^- in karst water is lighter by 8.62%.However,this does not mean that the karst water body has a larger carbon source effect.On the contrary,it means the karst water body has a greater karst carbon sink effect.When the karst subterranean stream in Zhaidi,Guilin,is exposed at the surface,carbon-rich karst water stimulated the growth of aquatic plants.The values of carbon stable isotopes in the same species of submerged plants gradually becomes heavier and heavier,and the 512 m flow process has a maximum range of 15.46%.The calculation results showed that 12.52% of inorganic carbon is converted into organic carbon.According to the data that has been published,the global karst carbon sink flux was estimated to be 0.53-0.58 PgC/a,equivalent to 31.18%-34.41% of the global forest carbon sink flux.In the meanwhile,the karst carbon sink flux in China was calculated to be 0.051 PgC/a,accounting for 68% of its forest carbon sink flux.Jian-hua Cao Xia Wu Fen Huang Bill Hu Chris Groves Hui Yang Chun-lai Zhang 2018China Geology2018,1,1:9
10Tracing the Deep Carbon Cycle Using Metal Stable Isotopes: Opportunities and Challenges显示文摘The subduction of marine carbonates and carbonated oceanic crust to the Earth’s interior and the return of recycled carbon to the surface via volcanism may play a pivotal role in governing Earth’s atmosphere, climate, and biosphere over geologic time. Identifying recycled marine carbonates and evaluating their fluxes in Earth’s mantle are essential in order to obtain a complete understanding of the global deep carbon cycle (DCC). Here, we review recent advances in tracing the DCC using stable isotopes of divalent metals such as calcium (Ca), magnesium (Mg), and zinc (Zn). The three isotope systematics show great capability as tracers due to appreciable isotope differences between marine carbonate and the terrestrial mantle. Recent studies have observed anomalies of Ca, Mg, and Zn isotopes in basalts worldwide, which have been interpreted as evidence for the recycling of carbonates into the mantle, even into the mantle transition zone (410–660 km). Nevertheless, considerable challenges in determining the DCC remain because other processes can potentially fractionate isotopes in the same direction as expected for carbonate recycling;these processes include partial melting, recycling of carbonated eclogite, separation of metals and carbon, and diffusion. Discriminating between these effects has become a key issue in the study of the DCC and must be considered when interpreting any isotope anomaly of mantle-derived rocks. An ongoing evaluation on the plausibility of potential mechanisms and possible solutions for these challenges is discussed in detail in this work. Based on a comprehensive evaluation, we conclude that the large-scale Mg and Zn isotope anomalies of the Eastern China basalts were produced by recycling of Mg- and Zn-rich carbonates into their mantle source.Sheng-Ao Liu Shu-Guang Li 2019Engineering2019,5,3:9
11Enhanced RuBisCO activity and promoted dicotyledons growth with degradable carbon dots显示文摘The ~ 5 nm degradable carbon dots (CDs) were synthesized directly from carbon rod by a one-step electrochemical method at room temperature.The as-prepared CDs can effectively enhance the ribulose bisphosphate carboxylase oxygenase (RuBisCO) activity,and then promote the dicotyledons growth (soybean,tomato,eggplant and so on) and finally increase their yields.Here,we used Arabidopsis thaliana and Trifolium repens L.as model plants to systematically study the beneficial effects of CDs on plant growth.These include:(i) accelerating seed germination;(ii) enlarging root elongation;(iii) increasing metal ions absorption and delivery;(iv) improving enzymes activity;(v) enhancing the carbohydrate content;(vi) degradation into plant hormone analogues and CO2;and finally (vii) enhancing the grain production by about 20%.Hao Li Jian Huang Yang Liu Fang Lu Jun Zhong Yong Wang Shuiming Li Yeshayahu Lifshitz Shuit-Tong Lee Zhenhui Kang 2019Nano Research2019,12,7:8
12The net primary productivity of Mid-Jurassic peatland and its control factors: Evidenced by the Ordos Basin显示文摘Using the large-scale thick 4# coal seam from the Mid-Jurassic in the southern Ordos Basin as an example, this paper studied the net primary productivity(NPP) level of the Mid-Jurassic peatland, and discussed its control factors. Geophysical logging signals were used for a spectrum analysis to obtain the Milankovitch cycle parameters in coal seam. These were then used to calculate the accumulation rate of the residual carbon in 4# coal seam. The carbon loss can be calculated according to the density and residual carbon content of 4# coal seam. Then, the total carbon accumulation rate of the peatland was further derived, and the NPP of peatland was determined. The results show that the NPP of MidJurassic peatland is higher than that of Holocene at the same latitude. Comprehensive analysis indicates that the temperature, carbon dioxide and oxygen levels in atmosphere are the main control factors of the NPP of Mid-Jurassic peatland.Wang Dongdong Yan Zhiming Liu Haiyan Lv Dawei Hou Yijun 2018International Journal of Mining Science and Technology2018,28,2:7
13Deep carbon cycle in subduction zones显示文摘The carbon cycle between the deep Earth and the atmosphere(i.e., the deep carbon cycle) can significantly affect the global climate on both long and short time scales. Although carbon in the deep Earth can be released to the atmosphere in many ways, plate subduction is the only pathway for the return of carbon from the surface to the deep Earth. Owing to diversity in the forms of carbon and the special physicochemical property of carbonates, the behavior of carbon and carbonates in subduction zones significantly affects the products of subduction processes, the oxygen fugacity in subduction zones, and the activation and migration of elements during the crust-mantle interaction. Therefore, the carbon cycle in subduction zones plays an important role in maintaining a habitable climate by regulating the atmospheric CO_2 concentration, which significantly affects the global climate, and in causing fundamental changes in the physical and chemical properties of the mantle that result in a heterogeneous mantle. In this study, we review and discuss previous studies and scientific problems regarding the carbon cycle in subduction zones from four aspects: observation and tracing of the carbon cycle, migration and variation of carbon during subduction,carbon flux, and the effect of the carbon cycle.Yongsheng LIU Chunfei CHEN Detao HE Wei CHEN 2019Science China Earth Sciences2019,62,11:7
14Spatial patterns of ecosystem carbon residence time in Chinese forests显示文摘Capacity of carbon sequestration in forest ecosystem largely depends on the trend of net primary production (NPP) and the length of ecosystem carbon residence time. Retrieving spatial patterns of ecosystem carbon residence time is important and necessary for accurately predicting regional carbon cycles in the future. In this study, a data-model fusion method that combined a process-based regional carbon model (TECO-R) with various ground-based ecosystem observations (NPP, biomass, and soil organic carbon) and auxiliary data sets (NDVI, meteorological data, and maps of vegetation and soil texture) was applied to estimate spatial patterns of ecosystem carbon residence time in Chinese forests at steady state. In the data-model fusion, the genetic algorithm was used to estimate the optimal model parameters related with the ecosystem carbon residence time by minimizing total deviation between modeled and observed values. The results indicated that data-model fusion technology could effectively retrieve model parameters and simulate carbon cycling processes for Chinese forest ecosystems. The estimated carbon residence times were highly heterogenous over China, with most of regions having values between 24 and 70 years. The deciduous needleleaf forest and the evergreen needleleaf forest had the highest averaged carbon residence times (73.8 and 71.3 years, respectively), the mixed forest and the deciduous broadleaf forest had moderate values (38.1 and 37.3 years, respectively), and the evergreen broadleaf forest had the lowest value (31.7 years). The averaged carbon residence time of forest ecosystems in China was 57.8 years.ZHOU Tao1,2, SHI PeiJun1,2, JIA GenSuo3, LI XiuJuan1,2 & LUO YiQi4 1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China 2 Academy of Disaster Reduction and Emergency Management, Ministry of Civil Affairs & Ministry of Education, Beijing 100875, China 3 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Chinese Academy of Sciences, Beijing 100029, China 4 Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA 2010Science China Earth Sciences2010,53,8:5
15Diagnosis of CO2 dynamics and fluxes in global coastal oceans显示文摘Global coastal oceans as a whole represent an important carbon sink but,due to high spatial–temporal variability,a mechanistic conceptualization of the coastal carbon cycle is still under development,hindering the modelling and inclusion of coastal carbon in Earth SystemModels.Although temperature is considered an important control of sea surface pCO2,we show that the latitudinal distribution of global coastal surface pCO2 does not match that of temperature,and its inter-seasonal changes are substantially regulated by non-thermal factors such as watermassmixing and net primary production.These processes operate in both ocean-dominated and river-dominated margins,with carbon and nutrients sourced from the open ocean and land,respectively.These can be conceptualized by a semi-analytical framework that assesses the consumption of dissolved inorganic carbon relative to nutrients,to determine how a coastal system is a CO2 source or sink.The framework also finds utility in accounting for additional nutrients in organic forms and testing hypotheses such as using Redfield stoichiometry,and is therefore an essential step toward comprehensively understanding and modelling the role of the coastal ocean in the global carbon cycle.Zhimian Cao Wei Yang Yangyang Zhao Xianghui Guo Zhiqiang Yin Chuanjun Du Huade Zhao Minhan Dai 2020National Science Review2020,7,4:5
16Increased biotic metabolism of the biosphere inferred from observed data and models显示文摘A 35 year record ot production and respiration in tne Northern Hemisphere bas been derived from monthly records of atmospheric concentration, fossil fuel combustion, and oceanic absorption of carbon dioxide using a method developed by Hall et al. The original conclusion of Hall et al. that there was no significant change in biotic metabolism, is confirmed by measuring both production and respiration from 1958 to 1972. But the analysis of the subsequent record shows that both production and respiration have been enhanced since the early 1970s by some large scale global change, probably of human origin. Our results also show that high-latitude regions in the Northern Hemisphere are changing more than regions further south. Nevertheless, the ratio of production to respiration (P/R) remains unchanged during the time period examined. Thus, no argument can be made for net carbon storage of or release from the biosphere from this analysis, although the turnover rate of the biosphere appears to be enhanced.田汉勤 CharlesA.S.Hall 叶琦 2000Science China Chemistry2000,43,1:5
17Redox evolution of western Tianshan subduction zone and its effect on deep carbon cycle显示文摘Knowing the phase relations of carbon-bearing phases at high-pressure(HP) and high-temperature(HT) condition is essential for understanding the deep carbon cycle in the subduction zones.In particular,the phase relation of carbon-bearing phases is also strongly influenced by redox condition of subduction zones,which is poorly explored.Here we summarized the phase relations of carbon-bearing phases(calcite,aragonite,dolomite,magnesite,graphite,hydrocarbon) in HP metamorphic rocks(marble,metapelite,eclogite) from the Western Tianshan subduction zone and high-pressure experiments.During prograde progress of subduction,carbonates in altered oceanic crust change from Ca-carbonate(calcite) to Ca,Mg-carbonate(dolomite),then finally to Mgcarbonate(magnesite) via Mg-Ca cation exchange reaction between silicate and carbonate,while calcite in sedimentary calcareous ooze on oceanic crust directly transfers to high-pressure aragonite in marble or amorphous CaCO3 in subduction zones.Redox evolution also plays a significant effect on the carbon speciation in the Western Tianshan subduction zone.The prograde oxygen fugacity of the Western Tianshan subduction zone was constrained by mineral assemblage of garnet-omphacite from FMQ-1.9 to FMQ-2.5 at its metamorphic peak(maximum P-T) conditions.In comparison with redox conditions of other subduction zones,Western Tianshan has the lowest oxygen fugacity.Graphite and light hydrocarbon inclusions were ubiqutously identified in Western Tianshan HP metamorphic rocks and speculated to be formed from reduction of Fe-carbonate at low redox condition,which is also confirmed by high-pressure experimental simulation.Based on petrological observation and high-pressure simulation,a polarized redox model of reducing slab but oxidizing mantle wedge in subduction zone is proposed,and its effect on deep carbon cycle in subduction zones is further discussed.Renbiao Tao Lijuan Zhang Lifei Zhang 2020Geoscience Frontiers2020,11,3:3
18MoS_2 decorated lignin-derived hierarchical mesoporous carbon hybrid nanospheres with exceptional Li-ion battery cycle stability显示文摘Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy group and carboxyl group, so it has great utilization value. We used lignin as a carbon source to prepare porous carbon nanosphere(PCN) materials, and in-situ synthesized the MoS_ 2 on its surface. The high specific surface area(462.8 m^2/g), large pore volume and good electron conductivity of the porous carbon scaffold facilitated the reversible electro-chemical reaction of S towards metallic Li, and thus the nano-hybrid showed a high specific energy and excellent cycle stability which still remained 520m Ah/g after 50 cycles.Feng Chen Long Wu Zeping Zhou Jiajun Ju Zhengping Zhao Mingqiang Zhong Tairong Kuang 2019Chinese Chemical Letters2019,30,1:3
19A Quantitative Process-Based Inventory Study on Material Embodied Carbon Emissions of Residential, Office, and Commercial Buildings in China显示文摘Studies on building carbon emissions focus mainly on the materialization phase of life cycle, as carbon emissions in this stage is intensive and high. This paper proposes a simplified model to calculate embodied carbon emissions in building design stage by conducting a process-based inventory analysis of carbon emissions from materials used in 129 residential buildings, 41 office buildings, and 21 commercial buildings during materialization phase. The results indicate that average carbon emissions per unit area from building materials used in residential buildings, office buildings, and commercial buildings are 514.66 kgCO2 e/m2, 533.69 kg CO2 e/m2 and 494.19 kgCO2 e/m2, respectively. Besides, ten kinds of building materials(namely, steel, commercial concrete, wall building materials, mortar, copper core cables, architectural ceramics, PVC pipes, thermal insulation materials, doors and windows, and water paint) constitute 99% of total carbon emissions in all three types of buildings. These materials are major carbon emissions sources in materialization phase. Thus, embodied carbon emissions can be significantly reduced by limiting the amount of these materials in architectural design as well as by using environmental friendly materials.LUO Zhixing CANG Yujie ZHANG Nan YANG Liu LIU Jiaping 2019Journal of Thermal Science2019,28,6:3
20The Mg-carbonate-Fe interaction:Implication for the fate of subducted carbonates and formation of diamond in the lower mantle显示文摘The fate of subducted carbonates in the lower mantle and at the core-mantle boundary was modelled via experiments in the MgCO3-Fe^0 system at 70-150 GPa and 800-2600 Kin a laser-heated diamond anvil cell.Using in situ synchrotro n X-ray diffraction and ex situ transmission electron microscopy we show that the reduction of Mg-carbonate can be exemplified by:6 MgCO3+19 Fe=8 FeO+10(Mg0.6Fe^0.4)O+Fe7 C3+3 C.The presented results suggest that the interaction of carbonates with Fe^0 or Fe^0-bearing rocks can produce Fe-carbide and diamond,which can accumulate in the D'region,depending on its carbon to Fe ratio.Due to the sluggish kinetics of the transformation,diamond can remain metastable at the core-mantle boundary(CMB)unless it is in a direct contact with Fe-metal.In addition,it can be remobilized by redox melting accompanying the generation of mantle plumes.Naira S.Martirosyan Konstantin D. Litasov Sergey S. Lobanov Alexander F. Goncharov Anton Shatskiy Hiroaki Ohfuji Vitali Prakapenka 2019Geoscience Frontiers2019,10,4:2
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