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Reassessment of historical sections from the Paleogene marine margin of the Congo Basin reveals an almost complete absence of Danian deposits

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Geoscience Frontiers 2019年第3期10卷 1039-1063页

作者： Floréal Solé Corentin Noiret Delphine Desmares Sylvain Adnet Louis Taverne Thierry De Putter Florias Mees johan Yans Thomas Steeman Stephen Louwye Annelise Folie nancy j.stevens Gregg F.Gunnell Daniel Baudet Nicole Kitambala Yaya Thierry Smith Royal Belgian Institute of Natural Sciences (RBINS) Operational Directorate Earth and History of Life University of Namur (UNamur) Department of Geology Rue de Bruxelles 61 Sorbonne Université UPMC Paris 06 UMR 7207 (CR2P) UMR 5554-Institut des Sciences de l'Evolution Université Montpellier Place E.Bataillon Royal Museum for Central Africa (RMCA) Geodynamics and Mineral Resources Leuvensesteenweg 13 Ghent University (UGent) Department of Geology Royal Belgian Institute of Natural Sciences (RBINS) Heritage Scientific Survey Ohio University Department of Biomedical Sciences Heritage College of Osteopathic Medicine Duke University Lemur Center Division of Fossil Primates (DFP) Centre de Recherches Géologiques et Minières (CRGM) 44 av.de la Démocratie Kinshasa Gombe

The early Paleogene is critical for understanding global biodiversity patterns in modern ecosystems. During this interval, Southern Hemisphere continents were largely characterized by isolation and faunal endemism following the breakup of Gondwana. Africa has been proposed as an important source area for the origin of several marine vertebrate groups but its Paleogene record is poorly sampled, especially from sub-Saharan Africa. To document the early Paleogene marine ecosystems of Central Africa, we revised the stratigraphic context of sedimentary deposits from three fossil-rich vertebrate localities: the Landana section in the Cabinda exclave(Angola), and the Manzadi and Bololo localities in western Democratic Republic of *** provide more refined age constraints for these three localities based on invertebrate and vertebrate faunas, foraminiferal and dinoflagellate cyst assemblages, and carbon isotope records. We find an almost complete absence of Danian-aged rocks in the Landana section, contrary to prevailing interpretations over the last half a century(only the layer 1, at the base of the section, seems to be Danian). Refining the age of these Paleocene layers is crucial for analyzing fish evolution in a global framework, with implications for the early appearance of Scombridae(tunas and mackerels) and Tetraodontiformes(puffer fishes). The combination of vertebrate fossil records from Manzadi and Landana sections suggests important environmental changes around the K/Pg transition characterized by an important modification of the ichthyofauna. A small faunal shift may have occurred during the Selandian. More dramatic is the distinct decrease in overall richness that lasts from the Selandian to the Ypresian. The Lutetian of West Central Africa is characterized by the first appearance of numerous cartilaginous and bony fishes. Our analysis of the ichthyofauna moreover indicates two periods of faunal exchanges: one during the Paleocene, where Central Africa app

关键词： Central Africa Paleogene Stratigraphy Carbon isotope Planktonic foraminifera Vertebrates

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Sustainable plasticulture in Chinese agriculture: a review of challenges and routes to achieving long-term food and ecosecurity

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Frontiers of Agricultural Science and Engineering 2024年第1期11卷 155-168页

作者： Samuel j.CUSWORTH William j.DAVIES Martin R.MCAINSH Carly j.stevens Weilu WANG Lancaster Environment Centre Lancaster UniversityLancasterLA14YQUK The Institutes of Agricultural Science and Technology Development Yangzhou UniversityYangzhou 225009China

Plastic pollution is global concern, affecting most aspects of global food production systems. Plasticulture, a practice used in agriculture to improve crop quality and quantity, among other factors, is a significant source of plastic pollution. This review examines the extent of plasticulture in China, the implications of the practice across decades of use and the legislative instruments used to resolve those issues. It briefly assesses the effectiveness of these policies and proposes possible future innovations to promote increases in long-term food and eco-security, where sustainable plasticulture is a key agent for change. While plasticulture has increased agricultural productivity in growth-limiting conditions, plastic pollution in agricultural soils has become acute in China. Consequently, plastic pollution is having deleterious effects on soil health and in turn, crop productivity in China. Plastic pollution in agriculture is a multifaceted issue and so proposed solutions should be informed by this complexity. Current measures do not reflect a holistic approach to solving this socioecological challenge and adopt a top-down approach, with little or no supportive mechanisms. Future recommendations need to consider the particular set of conditions that influence the production, use and end-of-life management of agriplastics,specific to the environmental, economic and social conditions in each location.

关键词： Circular plastics economy crop production food security plastic pollution sustainable plasticulture

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Diet variability of snappers(Teleostei:Lutjanidae)in a bay-to-reef ecosystem of the Mexican Caribbean

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Water Biology and Security 2024年第1期3卷 53-59页

作者： Leon Felipe Martínez-juarez juan j.Schmitter-Soto nancy Cabanillas-Teran Norman Mercado-Silva El Colegio de la Frontera Sur 77014ChetumalQuintana RooMexico Centro de Investigacion en Biodiversidad y Conservacion Universidad Autonoma del Estado de Morelos62209CuernavacaMorelosMexico

Fishes use environmental resources *** ontogenic movements among coastal habitats lead to diverse *** investigated the diets of seven snapper species(Lutjanus apodus,***,***,***,***,***,and Ocyurus chrysurus)in three interconnected coastal environments in the western Caribbean:Río Huach channel,Chetumal/Corozal bay,and the adjacent Xcalak reef *** three encompass all habitats used by the seven species in the study *** diets were mostly composed of fish and crustaceans,but dominance of either group varied among the studied habitats;for example,fish were the main prey for *** from the reef lagoon zone,but second in the *** are piscivorous-invertivorous mesopredators;the species that relied the most on fishes were *** and ***,whereas *** preferred *** content results revealed a high degree of dietary overlap among *** findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas,supporting the hypothesis of niche *** results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.

关键词： Resource partitioning Chetumal/Corozal bay Quintana Roo Trophic ecology

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Effect of nitrogen addition, form and clipping on competitive interactions between grassland species

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journal of Plant Ecology 2014年第3期7卷 222-230页

作者： Carly j.stevens David j.G.Gowing Lancaster Environment Centre Lancaster UniversityLancasterLA14YQUK Department of Earth Environment and EcosystemsThe Open UniversityWalton HallMilton KeynesMK76AAUK

Aims Although the effects of N addition on plant biomass are well understood,we know a lot less about the importance of N form even though some studies have shown different impacts from reduced and oxidized forms of ***,responses to grazing are likely to interact with the response to N *** experiment investigates the interactive effects of N addition and form with clipping on competition between three grassland *** The three species(Anthoxanthum odoratum L.,Plantago lanceolata *** Prunella vulgaris L.)were grown alone and in combination with factorial additions of deionized water,sodium nitrate and ammonium chloride,and a clipping ***-and belowground biomass was harvested after 4 *** Findings In monocultures,the results show increases in biomass with N addition,but clipping resulted in fewer changes with species displaying varying degrees of growth *** was the strongest competitor when grown with other *** monocultures without clipping,N form was not important,but in the presence of clipping and in different species combinations,N form became *** two-and three-way interactive effects were observed showing that complex interactions exist between N addition,clipping and species *** results have important implications when considering the effects of N deposition.

关键词： aboveground biomass ammonium grazing nitrate root biomass

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Nitrogen deposition and reduction of terrestrial biodiversity:Evidence from temperate grasslands

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Science China(Life Sciences) 2005年第Z2期48卷 720-728页

作者： nancy B.Dise Carly j.stevens Department of Earth Sciences Open University Milton KeynesMK7 6AAUK Department of Biology Villanova UniversityVillanovaPA 19085USA Department of Agricultural Science Imperial College at WyeWyeAshfordTN25 4NJUK

Biodiversity is thought to be essential for ecosystem stability, function and long-term sustainability. Since nitrogen is the limiting nutrient for plant growth in many terrestrial ecosystems, reactive nitrogen has the potential to reduce the diversity of terrestrial vegetation and associated biota through favouring species adapted to quickly exploiting available nutrients. Although the potential has long been recognised, only recently has enough evidence come together to show beyond reasonable doubt that these changes are already occurring. Linked together, experimental, regional/empirical, and time-series research provide a powerful argument that enhanced deposition of reactive nitrogen across Great Britain, and potentially the rest of Europe, has resulted in a significant and ongoing decline in grassland species richness and diversity.

关键词： nitrogen deposition, terrestrial biodiversity, temperate grasslands.

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Effects of the frequency and the rate of N enrichment on community structure in a temperate grassland

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journal of Plant Ecology 2018年第5期11卷 685-695页

作者： Yunhai Zhang jing Wang Carly j.stevens Xiaotao Lü Nianpeng He Changhui Wang Xingguo Han State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesNo.20 NanxincunXiangshanBeijing 100093China Lancaster Environment Centre Lancaster UniversityLancaster LA14YQUK Department of Agroecology Aarhus UniversityBlichers Allé20Tjele 8830Denmark University of the Chinese Academy of Sciences No.19 Yuquan RoadShijingshan DistrictBeijing 100049China Erguna Forest-Steppe Ecotone Research Station CAS Key Laboratory of Forest Ecology and ManagementInstitute of Applied EcologyChinese Academy of SciencesNo.72 Wenhua RoadShenhe DistrictShenyang 110016China Synthesis Research Center of Chinese Ecosystem Research Network Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences11ADatun RoadChaoyang DistrictBeijing 100101China

Aims Nitrogen(N)enrichment caused by human activities threatens bio-diversity and alters plant community composition and *** has been found that heavy and infrequent N inputs may over-estimate species extinction,but it remains unclear whether plant community structure will equally respond to frequent reactive N enriched *** We independently manipulated the rates and the frequencies of N addition in a temperate steppe,northern China,between 2008 and *** Findings We found that plant community structure changes,measured by‘Euclidean distance’involving species richness,composition and productivity,were significantly positively related to increasing N enrichment rates rather than *** in aboveground net primary productivity(ANPP),plant species richness and shifts in dominant species were *** ANPP increased with N enrichment,whereas species richness *** frequency of N enrichment increased species richness but had no impacts on community ANPP and the relative ANPP of the two dominant spe-cies,C3 perennial bunchgrass Stipa grandis and C3 perennial rhi-zome grass Leymus *** ANPP and relative ANPP of the two dominant species were significantly negatively correlated with each ***,changes in the relative ANPP of *** was negatively associated with the changes in community *** 5 years’treatment,direct influence of the frequency of N en-richment on plant community structure was not observed,but the effects of the rate of N enrichment were *** results sug-gested that further study in various ecosystems and with long-term and well-controlled comparisons the frequency *** rate of N enrichment may still be needed.

关键词： biodiversity dominance effect nitrogen addition frequency nitrogen deposition productivity

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RESEARCH PROGRESS ON THE IMPACT OF NITROGEN DEPOSITION ON GLOBAL GRASSLANDS

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Frontiers of Agricultural Science and Engineering 2022年第3期9卷 425-444页

作者： Carly j.stevens Sofía BASTO Michael DBELL Tianxiang HAO Kevin KIRKMAN Raul OCHOA-HUESO Lancaster Environment Centre Lancaster UniversityLancasterLA14YQUK Unidad de Ecologia y Sistematica Departamento de BiologiaFacultad de CienciasPontificia Universidad JaverianaCarrera 7 No.43-82 Ed.Jesus Emilio Ramirez(53)BogotaColombia National Park Service Air Resources DivisionLakewoodCO 80235USA Synthesis Research Center of Chinese Ecosystem Research Network Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environmental Sciences National Academy of Agriculture Green DevelopmentKey Laboratory of Plant-Soil Interactions of Ministry of EducationBeijing Key Laboratory of Farmland Soil Pollution Prevention and RemediationChina Agricultural UniversityBeijing 100193China School of Life Sciences University of KwaZulu-NatalDurban4041South Africa Departamento de Biologia-IVAGRO Universidad de CadizCampus Rio San Pedro11510 Puerto RealSpain Department of Terrestrial Ecology Netherlands Institute of Ecology(NIOO-KNAW)P.O.Box 506700 ABWageningenthe Netherlands

Grasslands are globally-important ecosystems providing critical ecosystem *** species composition and characteristics of grasslands vary considerably across the planet with a wide variety of different grasslands ***,in many regions grasslands have been impacted by atmospheric nitrogen deposition originating from anthropogenic activities with effects on productivity,species composition and diversity widely *** vary across grassland habitats but many show declines in species richness and increases in biomass production related to soil eutrophication and *** a continental level,there is considerable variation in the research effort that has been put into understanding the impacts of nitrogen *** Europe,North America and parts of Asia,although there are unanswered research questions,there is a good understanding of N deposition impacts in most grassland *** is not the case in other regions with large knowledge gaps in some parts of the *** paper reviews the impacts of N deposition on grasslands around the world,highlighting recent advances and areas where research is still needed.

关键词： acidification biomass production critical load eutrophication species composition species richness

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Dynamics of self-hybridized exciton–polaritons in 2D halide perovskites

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Light(Science & Applications) 2024年第1期13卷 13-22页

作者： Surendra B.Anantharaman jason Lynch Christopher E.stevens Christopher Munley Chentao Li jin Hou Hao Zhang Andrew Torma Thomas Darlington Francis Coen Kevin Li Arka Majumdar Pjames Schuck Aditya Mohite Hayk Harutyunyan joshua R.Hendrickson Deep jariwala Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA KBR Inc. BeavercreekOH45431USA Air Force Research Laboratory Sensors DirectorateWright-Patterson Air Force BaseOH45433USA Department of Physics University of WashingtonSeattleWA98195USA Department of Physics Emory UniversityAtlantaGA30322USA Department of Chemical and Biomolecular Engineering Rice UniversityHoustonTX77005USA Department of Materials Science and Nanoengineering Rice UniversityHoustonTX77005USA Applied Physics Program Smalley‐Curl InstituteRice UniversityHoustonTX77005USA Department of Mechanical Engineering Columbia UniversityNew YorkNY10027USA Department of Electrical and Computer Engineering University of WashingtonSeattleWA98195USA

Excitons,bound electron–hole pairs,in two-dimensional hybrid organic inorganic perovskites(2D HOIPs)are capable of forming hybrid light-matter states known as exciton-polaritons(E–Ps)when the excitonic medium is confined in an optical *** the case of 2D HOIPs,they can self-hybridize into E–Ps at specific thicknesses of the HOIP crystals that form a resonant optical cavity with the ***,the fundamental properties of these self-hybridized E–Ps in 2D HOIPs,including their role in ultrafast energy and/or charge transfer at interfaces,remain ***,we demonstrate that>0.5µm thick 2D HOIP crystals on Au substrates are capable of supporting multiple-orders of self-hybridized E–P *** E–Ps have high Q factors(>100)and modulate the optical dispersion for the crystal to enhance sub-gap absorption and *** varying excitation energy and ultrafast measurements,we also confirm energy transfer from higher energy E–Ps to lower energy E–***,we also demonstrate that E–Ps are capable of charge transport and transfer at *** findings provide new insights into charge and energy transfer in E–Ps opening new opportunities towards their manipulation for polaritonic devices.

关键词： charge polar excitation

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检测地面温度记录中的气候信号

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气象科技 1999年第2期27卷 14-26页

作者： Gerald R.North Mark j.stevens 美国得克萨斯A&M大学

利用最佳信号检测理论于１００年的地面温度资料中寻找与４个特定辐射强迫的气候响应。分析中所用的资料来源于地球上的３６个单元，而且被限定在０．０６～０．１３ｒ／ａ的频带（１６．６７～７．６９ａ）内。估算了气候对太阳变率、... 详细信息

利用最佳信号检测理论于１００年的地面温度资料中寻找与４个特定辐射强迫的气候响应。分析中所用的资料来源于地球上的３６个单元，而且被限定在０．０６～０．１３ｒ／ａ的频带（１６．６７～７．６９ａ）内。估算了气候对太阳变率、火山气溶胶、温室气体和人类活动产生的气溶胶的响应强度。最佳滤波器由一个用二维能量平衡模式（ＥＢＭ）计算出的信号波形组成。最佳权重是用地球物理流体动力学实验室（ＧＦＤＬ）和Ｍａｘ－Ｐｌａｎｋ研究所耦合的海气模式的１０００年控制试验和噪声强迫的ＥＢＭ１００００年控制试验计算得到的。作者还利用了ＧＦＤＬ混和层模式的１０００年试验。结果这４个独立的模式有合理的一致性。我们发现，垂直于其他信号的火山分量非常强，且很显著。与此类似，垂直于其他信号的温室气体分量也非常强且很显著。当所有４个气候强迫组合时，气候响应超过噪音水平的３个标准差。

关键词：气候变化地面温度太阳变率温室气体气溶胶

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Microbial community structure across grazing treatments and environmental gradients in the Serengeti

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Soil Ecology Letters 2022年第1期4卷 45-56页

作者： Bo Maxwell stevens Derek Lee Sonderegger nancy Collins johnson School of Earth and Sustainability Northern Arizona UniversityFlagstaffAZ 86011USA Department of Mathematics and Statistics Northern Arizona UniversityFlagstaffAZ 86001USA Department of Biological Sciences Northern Arizona UniversityFlagstaffAZ 86011USA

As one of the last remaining naturally grazed ecosystems on Earth,the Serengeti National Park is an ideal location to study the influence of migratory mammals on the structure of microbial communities and the factors that generate biogeography of soil ***,volcanic inputs generate environmental gradients that may also structure microbial *** studied 16S rRNA amplicons in a 13-year herbivore removal experiment to examine the influence of grazing and environmental gradients on the natural distribution of soil *** of mammalian herbivores shifted microbial community structure,with 31 taxa that were significant indicator taxa of the ungrazed treatment and three taxa that were indicators of the grazed *** abundance of many taxa were correlated with soil texture,phosphorus,iron,calcium and rainfall,and the evenness of taxa within samples was also correlated with these *** general linear mixed effects models with single predictors of multiple,highly correlated variables of beta diversity were consistent with a significant,but weak(2%),effect of grazing,and stronger effects of phosphorus(14%).Beta diversity of microbial communities was greater in grazed than in ungrazed plots;suggesting that the impacts of grazing on community assembly of microbes results from deterministic environmental filtering caused by the influence of herbivores on plant communities and soil properties rather than stochastic dispersal via herds of large *** herbivore effects are superimposed on deterministic environmental filtering by natural soil and precipitation gradients across the Serengeti.

关键词： Soil bacteria Community ecology Grazing Serengeti National Park Soil texture Phosphorus

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