检索结果-南通市图书馆

The great catastrophe: causes of the Permo-Triassic marine mass extinction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall David P.G.Bond School of earth & Environment University of Leeds School of environmental sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Plant type effect overweighs seasonal variation in n-alkanoic acid biomarker on regional Loess Plateau of China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China earth sciences 2024年第8期67卷 2547-2562页

作者： Jinzhao LIU S.Nemiah LADD Jiaju ZHAO Dongna YAN Ding HE Yunning CAO Zhisheng AN State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China department of environmental sciences University of BaselBasel 4056Switzerland department of ocean Science and Center for ocean Research in Hong Kong and Macao The Hong Kong University of Science and TechnologyHong Kong 999077China

The effect of plant type on n-alkane biomarker has been widely studied,but the influence of plant type on n-alkanoic acids(n-FAs)has received less *** the effect of the distribution of n-FAs and their hydrogen isotope composition(δ^(2)H_(FA))is critical for interpreting sedimentaryδ^(2)H_(FA)values as proxies of hydroclimate and/or vegetation *** this study,we systematically investigated the distribution ofn-FAs andδ^(2)H_(FA)values across seasons on the Chinese Loess Plateau(CLP).Our results showed that there were no significant seasonal differences in n-FAs distribution andδ^(2)H_(FA)values,but there were significant differences inδ^(2)H_(FA)values across plant ***δ^(2)H_(FA)values ranged from-185‰to-125‰in dicots(-161‰±28‰),and from-215‰to-170‰in monocots(-196‰±22‰)on the *** fractionation betweenδ^(2)H_(FA)values and precipitationδ^(2)H(ε_(FA-P))was also^(2)H-enriched in dicots relative to *** the regional scale of the CLP,δ^(2)H_(FA)values were not correlated withδ^(2)H values of ***,δ^(2)H_(FA)values from the CLP were similar to expectations from a global comparison,both in terms of their mean values and high variability among plants growing in sites with similarδ^(2)H values of *** some of this variability inεFA-Pis due to the effect of plant type,a careful assessment of the likely sources of waxes in terrestrial sediments is critical when usingδ^(2)H_(FA)values for paleohydroclimate reconstruction.

关键词： n-Alkanoic acid Hydrogen isotope Plant type Paleohydroclimate Chinese Loess Plateau

A holistic perspective on earth system science

在线全文

学校读者我要写书评

暂无评论

Science China earth sciences 2024年第10期67卷 3013-3040页

作者： Yongfei ZHENG Zhengtang GUO Nianzhi JIAO Mu MU Shilong PIAO Suiyan FU Dinghui YANG Maoyan ZHU State Key Laboratory of Lithospheric and environmental Coevolution School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China State Key Laboratory of Lithospheric and environmental Coevolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of ocean and earth sciences Xiamen UniversityXiamen 361102China department of Atmospheric and oceanic sciences Fudan UniversityShanghai 200438China School of Environment Peking UniversityBeijing 100871China School of earth and Space sciences Peking UniversityBeijing 100871China department of Mathematical sciences Tsinghua UniversityBeijing 100084China Nanjing Institute of Geology and Palaeontology Chinese Academy of SciencesNanjing 210008China

earth system can be categorized into three parts, solid earth system, surface earth system, and Sun-earth space system. These three subsystems not only have mutual transmission and coupling relationships in both energy and matter but also involve multiple scales from microscopic to macroscopic. earth system science is characterized by its globality and unity with a holistic view and a systematic view at multiple scales in both space and time. It focuses not only on the physical, chemical and biological interactions between various geospheres but also on the properties, behaviors, processes, and mechanisms of the entire earth and its spheres. Although significant progress has been made in the study of internal disciplines of these three subsystems,there is still insufficient understanding of their overall behavior and interactions between individuals, thus facing challenges of different types and levels. The solid earth system is composed of the crust, mantle, and core. Existing observational techniques struggle to penetrate deep into the mantle, making direct observation and data acquisition difficult;the extreme environments within earth, such as high temperature, high pressure, and strong magnetic fields, also pose great challenges to observational equipment and scientific experiments. The surface earth system is an open complex mega-system, in which there are complex interactions and feedback mechanisms among its geospheres(such as atmosphere, hydrosphere, biosphere, pedosphere and lithosphere), leading to difficulties in understanding of its overall behavior and long-term evolution. Biological activities have become increasingly significant in affecting the surface earth system. The coupling between the internal and external earth systems becomes more complex. Distinguishing and quantifying the impacts of earth spherical interactions and biological activities on the surface earth system is a major challenge. The Sun-earth space system involves multiple physical

关键词： earth's interior earth's exterior Geospheres Energy exchange Material transfer

Petrologic evolution of the Gysian ophiolitic serpentinites,NW Iran

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第5期43卷 996-1011页

作者： Monir Modjarrad Donna L.Whitney Hadi Omrani department of Geology Faculty of SciencesUrmia UniversityUrmiaIran department of earth and environmental sciences University of MinnesotaMinneapolisMNUSA department of Geology Faculty of SciencesGolestan UniversityGorgānIran

The Gysian ophiolite of NW Iran is located at the intersection of the ophiolite belts of SE Turkey,NE Iraq,and Iran,and provides the opportunity to investigate the preserved subduction and obduction history of an important tectonic site that has not previously been *** serpentinized peridotites of the Gysian ophiolite contain the assemblagelizardite+chrysotile+spinel/Mg-spinelwith relict clinopyroxene(diopside)and very rare relict orthopyroxene and *** compositions of clinopyroxenes and spinels are more consistent with the formation of the inferred protolithharzburgitesinafore-arcorsupra-subduction zone instead of an abyssal *** Gysian ophiolite is a remnant of the Neo-Tethyan arc-ophiolitic system and records shallow subduction(<50 km,indicated by the absence of antigorite)in the Late Cretaceous to Paleocene beforeobductionalongthrustfaultsoverthecontinental *** review the spatial trends of the metamorphic grade of the Neo-Tethyan ophiolites in this region and provide detailed information about the petrology and mineral chemistry of the Gysian ophiolite.

关键词： Ophiolite Neo-Tethyan Gysian Serpentinite Iran

Effect of stress-dependent microannulus aperture on well leakage

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1967-1976页

作者： Meng Meng Luke P.Frash J.William Carey Mohamed Mehana Wenfeng Li Bailian Chen earth and environmental sciences Los Alamos National LaboratoryLos AlamosNMUSA

Debonding at the cement-casing interface is recognized as a principal failure mechanism leading to CO_(2) leakage in *** detachment gives rise to a microannulus,which notably possesses greater permeability than undamaged cement,undermining its sealing ***,the permeability of the microannulus is regarded as a uniform value throughout the ***,fundamentally,a microannulus is one type of fracture,and its gap or aperture size is affected by the effective *** this work,we developed a unique experimental *** equipment facilitates the curing of cement inside a steel casing,the formation of a microannulus between the casing and the cement,and the investigation of the fluid flow dynamics along the microannulus under laboratory-replicated in situ *** microannulus was formed by injecting fluid from one end of the setup,and receiving similar amount of fluid on the other end signified the development of the leakage ***,strain gauges affixed to the casing’s external surface yielded key information on the microannulus’s opening and *** observed a noticeable decline in microannulus hydraulic aperture(or permeability)in relation to effective stress and an exponential equation fits their *** findings also indicate a distinct behavior when comparing liquid CO_(2) with ***,it is easier for liquid CO_(2) to create the ***,the hydraulic aperture range for this microannulus(0.7-6 mm)is considerably smaller than that created by water flow(2-17 mm).Finally,we integrated the stressdependent microannulus aperture size into the combined analysis of well mechanical integrity and well *** outcomes consistently demonstrated that when factoring in the stress-dependent aperture sizes,the leakage rates are 3e5 times compared to a fixed aperture *** traditional assumption of a constant aperture significantly underestimates fluid leakage risks.

关键词： Microannulus Leakage assessment Aperture size Triaxial experiment Carbon sequestration

A remarkable decade of learning and sharing knowledge through the Journal of Palaeogeography(JoP)(2014-2024):Reminiscences from an Associate Editor-in-Chief

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第4期13卷 1029-1040页

作者： G.Shanmugam department of earth and environmental sciences The University of Texas at Arlington

In this editorial, an Associate Editor-in-Chief of the Journal of Palaeogeography(JoP) reminisces his publication experience in JoP during the period 2014-2024. 1) During a period of nine years, he contributed eight review articles, three discussions, two replies, one book review, one glossary, and one tribute to the first Editor-in-Chief Prof. Zeng-Zhao Feng. His contributions totaled 534 printed pages. 2) His contributions examined 19 different domains, such as landslides, submarine fans, seismites, SSDS, hyperpycnites, rivers,etc. 3) His contributions coincided with the formative years of JoP. 4) The impact of his articles is evident from the Stats published by ResearchGate. For example, his review article “The Landslide Problem” has reached11,611 Reads and 186 Citations after nine years of publication in 2015. 5) In 2023, the CNKI(China National Knowledge Infrastructure) recognized his article “Submarine fans: a critical retrospective(1950-2015)” as the Top-1% most-highly cited publications in the Journal of Palaeogeography published during a 10-year survey period: 2012-2022. 6) He was inducted as a Founding Member of the International Society of Palaeogeography(ISP) at Changping District of China University of Petroleum(Beijing), Beijing on July 16, 2022. 7) His JoP editorship during the past 10 years has been the most challenging, inspiring, and rewarding experience of his global scientific journey spanning over six decades(1962-2024).

关键词： Journal of Palaeogeography Associate Editor-in-Chief Editorial Landslides Submarine fans Seismites SSDS Hyperpycnites Zeng-Zhao Feng

Characterization of a Novel Esterase Belonging to Family V from Marinobacter flavimaris

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of ocean University of China 2024年第1期23卷 221-232页

作者： HE Jingjing ZHANG Yunhui WU Leilei WANG Yaru ZHANG He LIU Zhengang SHI Xiaochong Frontiers Science Center for Deep ocean Multispheres and earth System and College of Marine Life SciencesOcean University of ChinaQingdao 266003China Laboratory for Marine Ecology and environmental Science Laoshan LaboratoryQingdao 266237China Institute of Evolution&Marine Biodiversity Ocean University of ChinaQingdao 266003China

Lipolytic enzymes have attracted enormous attentions because of their ability in ester hydrolysis,ester synthesis,transesterification and other biochemical *** are important sources of lipolytic enzymes applied in ***,a novel lipolytic enzyme encoded by esterase gene est1347 was identified in Marinobacter flavimaris WLL162,and was purified and *** lipolytic enzyme Est1347 consisted of 312 amino acid residues and a 21-amino-acids N-terminal signal peptide with a predicted molecular weight of 34.2 *** belongs to family V of bacterial lipolytic enzymes based on the amino acid sequence homology ***1347 is a mesophilic and alkali-resistant enzyme with the highest activity at 45℃and pH 8.5;it is stable at temperatures below 50℃and pH 7.5–***1347 showed a preference for middle-length chain substrate p-NPC10 and a wide range of other *** Km,Vmax,Kcat and Kcat/Km values of Est1347 for p-NPC10 in pH 8.5 at 45℃were 0.9411 mmol L^(−1),1285μmol min^(−1)mg^(−1),698.91 s^(−1)and 743.65 s^(−1)(mmol L^(−1))^(−1),*** is also tolerant to the metal ions,organic solvents and *** conclusion,the esterase Est1347 laid a foundation for further study of bacterial lipolytic enzyme family V.

关键词： esterase Marinobacter flavimaris enzymatic properties lipolytic enzyme family V

Pumping-induced Well Hydraulics and Groundwater Budget in a Leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2024年第2期98卷 477-490页

作者： ZHUANG Chao LÜChenyang YAN Long LI Yabing ZHOU Zhifang WANG Jinguo DOU Zhi Walter A.ILLMAN School of earth sciences and Engineering Hohai UniversityNanjing 211100China School of Geography Earth and Environmental SciencesUniversity of BirminghamBirmingham B152TTU.K. department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China department of earth and environmental sciences University of WaterlooOntario N2L 3G1Canada

In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical *** investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard *** of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater *** the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer *** using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to calculate aquitard depletion and unconfined aquifer leakage.

关键词： hydrogeology aquitard vertical heterogeneity semi-analytical solution well hydraulics groundwater budget

Application of the Conditional Nonlinear Local Lyapunov Exponent to Second-Kind Predictability

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric sciences 2024年第9期41卷 1769-1786页

作者： Ming ZHANG Ruiqiang DING Quanjia ZHONG Jianping LI Deyu LU State Key Laboratory of earth Surface Processes and Resource Ecology(ESPRE)/Key Laboratory of environmental Change and Natural Disasters of Chinese Ministry of EducationBeijing Normal UniversityBeijing 100875China department of ocean Science Hong Kong University of Science and TechnologyHong KongChina College of oceanic and Atmospheric sciences/Frontiers Science Center for Deep ocean Multispheres and earth System(DOMES)/Key Laboratory of Physical oceanography Ministry of Education/Academy of the Future Ocean/Center for Ocean Carbon NeutralityOcean University of ChinaQingdao 266100China Laoshan Laboratory Qingdao 266237China State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of earth Science University of Chinese Academy of SciencesBeijing 100049China

In order to quantify the influence of external forcings on the predictability limit using observational data,the author introduced an algorithm of the conditional nonlinear local Lyapunov exponent(CNLLE)*** effectiveness of this algorithm is validated and compared with the nonlinear local Lyapunov exponent(NLLE)and signal-to-noise ratio methods using a coupled Lorenz *** results show that the CNLLE method is able to capture the slow error growth constrained by external forcings,therefore,it can quantify the predictability limit induced by the external *** this basis,a preliminary attempt was made to apply this method to measure the influence of ENSO on the predictability limit for both atmospheric and oceanic variable *** spatial distribution of the predictability limit induced by ENSO is similar to that arising from the initial conditions calculated by the NLLE *** similarity supports ENSO as the major predictable signal for weather and climate *** addition,a ratio of predictability limit(RPL)calculated by the CNLLE method to that calculated by the NLLE method was *** RPL larger than 1 indicates that the external forcings can significantly benefit the long-term predictability *** instance,ENSO can effectively extend the predictability limit arising from the initial conditions of sea surface temperature over the tropical Indian ocean by approximately four months,as well as the predictability limit of sea level pressure over the eastern and western Pacific ***,the impact of ENSO on the geopotential height predictability limit is primarily confined to the troposphere.

关键词： conditional nonlinear local Lyapunov exponent second-kind predictability coupled Lorenz model ENSO