期刊文献+
共找到195篇文章
< 1 2 10 >
每页显示 20 50 100
How topography and neighbor shape the fate of trees in subtropical forest restoration:Environmental filtering and resource competition drive natural regeneration
1
作者 Haonan Zhang Xingshuo Zhang +7 位作者 Yingying Lv Yanyan Ni Baokun Xu Xiangnan Han Xiao Cao Qingpei Yang Wanggu Xu Zhedong Qian 《Forest Ecosystems》 SCIE CSCD 2024年第1期73-86,共14页
The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering d... The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering due to microtopographic heterogeneity and resource competition among plants caused by spatial variation in tree density and size are considered to be very important in explaining the mechanisms of community assembly,their effects on the processes of individual mortality and recruitment in natural forest regeneration,as well as their relative contributions,are still poorly understood.To address this,we established a 12-ha permanent plot in a subtropical evergreen broad-leaved forest area and measured microtopographic variables such as elevation,slope,aspect,and terrain position index(TPI)using a total station.We monitored the individual mortality and recruitment in forest natural regeneration through repeated surveys at 5-year intervals.We fitted spatial covariance models to jointly use multiple factors from three groups of variables(microtopographic effect,neighborhood density effects,neighborhood size effects)as explanatory variables to analyze their roles in driving the mortality and recruitment of all individual and 12 dominant species in forest natural regeneration at the neighborhood scale.Our results show that:(1)In the crucial early stages of secondary forest restoration,natural regeneration is influenced by a synergy of environmental filtering,due to microtopographic heterogeneity,and resource competition among plants.(2)For distinct species responses,evergreen dominant species'mortality is largely explained by neighborhood effects,while deciduous species are more affected by topographic factors.Furthermore,the adverse effects of larger conspecific trees on younger trees indicate a pattern of competitive pressure leading to mortality among regenerating trees,such pattern emphasis the influence of parent trees on natural regeneration.(3)As trees grow,their interaction with these stressors evolves,suggesting a shift in their resource acquisition strategies and response to neighborhood effects and environmental factors.Despite these changes,the relative importance of topographic factors in determining survival and recruitment success remains constant.This research highlights the importance of considering both environmental and neighborhood effects in forest management,particularly in early secondary forest restoration. 展开更多
关键词 Natural regeneration MICROTOPOGRAPHY Neighborhood effects Mortality and recruitment
下载PDF
Epiphytic zooplankton community profiles in a typical urban wetland as revealed by DNA metabarcoding
2
作者 Diwen LIANG Chunrong HUANG +3 位作者 Senjie LIN Jiahua DONG Mingyi LIANG Hailin LUO 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第5期1571-1585,共15页
Zooplankton,a crucial component of urban wetland,are one of the effective bioindicators for monitoring the feeding stocks of organisms at higher trophic levels and assessing the ecological quality of ecosystems.Howeve... Zooplankton,a crucial component of urban wetland,are one of the effective bioindicators for monitoring the feeding stocks of organisms at higher trophic levels and assessing the ecological quality of ecosystems.However,information about the characteristics of epiphytic zooplankton community structure resulted from traditional methods is limited and hindered by the large amount of detritus and sludge attached to the macrophytes.We investigated the epiphytic zooplankton communities associated with macrophytes(Vallisneria,Nymphaea,and Thalia dealbata)in a subtropical wetland using as DNA markers of the 18 S rRNA gene and the mitochondrial cytochrome c oxidase subunit I(COI)gene.A total of 241 OTUs of zooplankton were obtained from COI amplicons,including 194 OTUs of Rotifera,22 of Cladocera,and 25 of Copepoda,while only 62 OTUs of zooplankton were obtained from 18 S rDNA amplicons including 34 OTUs of Rotifera and 28 of Copepoda.The zooplankton communities associated with the three macrophytes were similar,but they differed significantly from those in the open waters.However,there were no significant temporal differences among the zooplankton communities.Epiphytic zooplankton communities were dominated by littoral zooplankton such as Testudinella,Lecane,and Philodina.Microzooplankton,especially littoral species,utilize macrophytes as food sources and as refuges against predation.This further led to an increase inαandβdiversity of zooplankton communities in urban wetlands.Our result suggests that the joint use of multiple molecular markers could improve the taxonomic resolution and generate a comprehensive biodiversity profile of zooplankton. 展开更多
关键词 environmental DNA metabarcoding DIVERSITY MACROPHYTE cytochrome c oxidase subunit I(COI) 18 S rRNA
下载PDF
Analyzing the surface passivity effect of germanium oxynitride:a comprehensive approach through first principles simulation and interface state density
3
作者 Sheng-Jie Du Xiu-Xia Li +8 位作者 Yang Tian Yuan-Yuan Liu Ke Jia Zhong-Zheng Tang Jian-Ping Cheng Zhi Deng Yu-Lan Li Zheng-Cao Li Sha-Sha Lv 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第5期74-84,共11页
High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achiev... High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achieving an extremely low energy threshold.In this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface passivation.Theoretical calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface state.Based on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio structure.The microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state density.The mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents. 展开更多
关键词 Surface passivation High purity germanium detector Germanium nitrogen oxide Interface state density
下载PDF
Opportunity and shift of nitrogen use in China
4
作者 Wangzheng Shen Jing He +5 位作者 Sisi Li Yanhua Zhuang Hongyuan Wang Hongbin Liu Liang Zhang Andreas Kappler 《Geography and Sustainability》 CSCD 2024年第1期33-40,共8页
It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N p... It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries. 展开更多
关键词 Environmental Kuznets curve Nitrogen surplus Greenhouse gas emission Climate change Non-point source pollution
下载PDF
Distribution of phytoplankton in the East China Sea and the southern Yellow Sea in spring in relation to environmental variables and dimethylsulfide compounds 被引量:2
5
作者 Jiawei Zhang Yanghang Chen +7 位作者 Xueyan Ren Vishal Patil Lin Sun Xuesong Li Junrong Liang Jun Zhang Yahui Gao Changping Chen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第6期41-53,共13页
The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chl... The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chlorophyll a(Chl a)and their relationships with environmental variables and dimethylsulfide(DMS)and dimethylsulfoniopropionate(DMSP)were investigated in spring 2017(March 24 to April 16)in the East China Sea(26.0°-33.0°N,120.0°-128.0°E)and southern Yellow Sea(31.0°-36.0°N,120.0°-125.0°E).The spatial distributions of phytoplankton species composition and cell density were investigated by qualitative and quantitative methods and were compared with historical data to study phytoplankton species succession in the survey area.The results showed that there were 275 phytoplankton species belonging to 90 genera and 6 phyla in the survey area,of which 208 species belonged to 62 genera of Bacillariophyta and 56 species belonged to 20 genera of Pyrrophyta.The dominant phytoplankton species were Skeletonema dohrnii,Chaetoceros vanheurckii and Prorocentrum donghaiense.The phytoplankton cell densities ranged from 0.06×10^(4)cells/L to 418.73×10^(4)cells/L,with an average value of 21.46×10^(4)cells/L.In spring,the average ratio of Bacillariophyta/Pyrrophyta was41.13 for the entire study area.The areas with high phytoplankton cell density were mainly distributed in the northern South Yellow Sea and offshore waters of the East China Sea.According to a canonical correspondence analysis among phytoplankton and environmental parameters,the water Chl a concentrations were notably consistent with phytoplankton cell density(P<0.001),and both showed significant negative correlations with salinity and nitrite(P<0.05)and significant positive correlations with dissolved oxygen and pH(P<0.001).There was a significant positive correlation between diatom(both in cell density and in dominant species)and DMS(P<0.05),which indicated that diatoms play a greater role in DMS production in this investigated area. 展开更多
关键词 PHYTOPLANKTON DISTRIBUTION East China Sea southern Yellow Sea DIMETHYLSULFONIOPROPIONATE
下载PDF
Hydrogeochemical characteristics of groundwater and pore-water and the paleoenvironmental evolution in the past 3.10 Ma in the Xiong’an New Area,North China 被引量:3
6
作者 Kai Zhao Jing-xian Qi +6 位作者 Yi Chen Bai-heng Ma Li Yi Hua-ming Guo Xin-zhou Wang Lin-ying Wang Hai-tao Li 《China Geology》 2021年第3期476-486,共11页
The groundwater level has been continuously decreasing due to climate change and long-time overexploitation in the Xiong’an New Area,North China,which caused the enhanced mixing of groundwater in different aquifers a... The groundwater level has been continuously decreasing due to climate change and long-time overexploitation in the Xiong’an New Area,North China,which caused the enhanced mixing of groundwater in different aquifers and significant changes in regional groundwater chemistry characteristics.In this study,groundwater and sediment pore-water in drilling cores obtained from a 600 m borehole were investigated to evaluate hydrogeochemical processes in shallow and deep aquifers and paleo-environmental evolution in the past ca.3.10 Ma.Results showed that there was no obvious change overall in chemical composition along the direction of groundwater runoff,but different hydrochemical processes occurred in shallow and deep groundwater in the vertical direction.Shallow groundwater(<150 m)in the Xiong’an New Area was characterized by high salinity(TDS>1000 mg/L)and high concentrations of Mn and Fe,while deep groundwater had better water quality with lower salinity.The high TDS values mostly occurred in aquifers with depth<70 m and>500 m below land surface.Water isotopes showed that aquifer pore-water mostly originated from meteoric water under the influence of evaporation,and aquitard pore-water belonged to Paleo meteoric water.In addition,the evolution of the paleoclimate since 3.10 Ma BP was reconstructed,and four climate periods were determined by theδ18O profiles of pore-water and sporopollen records from sediments at different depths.It can be inferred that the Quaternary Pleistocene(0.78‒2.58 Ma BP)was dominated by the cold and dry climate of the glacial period,with three interglacial intervals of warm and humid climate.What’s more,this study demonstrates the possibilities of the applications of pore-water on the hydrogeochemical study and further supports the finding that pore-water could retain the feature of paleo-sedimentary water. 展开更多
关键词 GROUNDWATER PORE-WATER HYDROGEOCHEMISTRY Stable oxygen isotope Paleoclimate change Paleoenvironmental reconstruction Hydrogeological survey engineering Xiong’an New Area North China
下载PDF
Optical Characteristics of Chromophoric Dissolved Organic Matter(CDOM)in Upstream and Downstream Lakes of Taihu Lake Basin:New Insights for Water Environmental Management
7
作者 REN Weixiang WU Xiaodong +4 位作者 CHEN Bingfa CHAO Jianying GE Xuguang YANG Jiuyun YANG Hui 《Chinese Geographical Science》 SCIE CSCD 2022年第4期606-619,共14页
Chromophoric dissolved organic matter(CDOM)is a key component of organic matter that contributes to the ecological functioning of lakes.The lakes in Taihu Lake Basin play an important role in maintaining regional ecol... Chromophoric dissolved organic matter(CDOM)is a key component of organic matter that contributes to the ecological functioning of lakes.The lakes in Taihu Lake Basin play an important role in maintaining regional ecological stabilities;however,the optical characteristics of the CDOM in the upstream and downstream lakes in this basin have not yet been systematically studied.Here,the optical characteristics of CDOM in ten lakes of upstream and downstream of the Taihu Lake Basin were studied using UV-Visible and excitation-emission matrix spectroscopies.Three different fluorophores consisting of two humic-like components(C1,C2)and one protein-like component(C3)were identified by parallel factor analysis.Soil or surface erosion was responsible for the higher abund-ance of C1 in the upstream lakes,and increased biological activities accounted for the higher abundance of C3 in the downstream lakes.Rainfall erosion in the wet season led to an increase in CDOM.We also found that the photodegradation and flocculation degree,which played a significant role in reducing CDOM,were higher in downstream lakes than in upstream lakes.Optical analysis of CDOM provides a promising method for monitoring water qualities(e.g.,total phosphorus and potassium permanganate index)in each lake.Re-ductions in soil or surface erosion in the upstream are needed to improve water quality. 展开更多
关键词 Taihu Lake Basin chromophoric dissolved organic matter(CDOM) excitation-emission spectra parallel factor analysis(PARAFAC)
下载PDF
The Belt and Road Initiative and the 2030 Agenda for Sustainable Development:seeking linkages for global environmental governance 被引量:5
8
作者 Liang Dong Xiaohua Yang Hongtao Li 《Chinese Journal of Population,Resources and Environment》 2018年第3期203-210,共8页
Global environmental cooperation serves as an important part in the Chinese ideal of building a Community with a Shared Future for all Human Beings. The report of 19 th CPC National Congress indicates that China is co... Global environmental cooperation serves as an important part in the Chinese ideal of building a Community with a Shared Future for all Human Beings. The report of 19 th CPC National Congress indicates that China is committed to proactive mitigation under the Paris Agreement and further participating in global environmental governance under the 2030 Agenda for Sustainable Development, and both of which are largely integrated to the Belt and Road Initiative(BRI). BRI are also closely linked with South-South environmental and climate cooperation proposed by China from previous UN summits. Based on shared ideas, intersected agendas, and compatible governance approaches, BRI and the 2030 Agenda for Sustainable Development grow increasingly relevant and they might form synergies based on increasingly interactive relations. In sum,seeking and intensifying the linkages between BRI and 2030 sustainable development goals(SDGs) could address global environmental governance deficits and enhance cooperation among nations. 展开更多
关键词 The BELT and ROAD INITIATIVE 2030 AGENDA for Sustainable Development South-South cooperation INTERPLAY global environmental governance linkage climate change
下载PDF
Reflection and operationalization of the common but differentiated responsibilities and respective capabilities principle in the transparency framework under the international climate change regime 被引量:4
9
作者 WANG Tian GAO Xiang 《Advances in Climate Change Research》 SCIE CSCD 2018年第4期253-263,共11页
“Common but differentiated responsibilities and respective capabilities”(CBDRRC) is the most significant guiding principle in the international climate change regime, created by the United Nations Framework Conventi... “Common but differentiated responsibilities and respective capabilities”(CBDRRC) is the most significant guiding principle in the international climate change regime, created by the United Nations Framework Convention on Climate Change in 1992 and inherited by the Paris Agreement 24 years later. This paper examines the operationalization of the CBDRRC principle in one of the cornerstone rules of the regimedits transparency provisions, both in existing practice under the convention and possible evolvement in negotiations under the Paris Agreement, from the perspectives of both international rule-making and domestic implementation. The authors have found a continuous enhancement of the transparency framework since the 1990s, and gradual consolidation of a bifurcated system between developed and developing countries into a common one. The authors argue that the transparency framework, as part of the procedural rules, should be designed to facilitate transparent information sharing in accordance with substantive commitments under international climate change laws. Thus, it indirectly reflects historical responsibilities for climate change, while the framework should also be designed as feasible and reflective of the respective capabilities of nations. Finally, the evolution of the transparency framework will aim to enact common and enhanced provisions while differentiating between developed and developing countries in the near term, and greater transparency-related capacity-building for developing countries. 展开更多
关键词 INTERNATIONAL climate change law UNFCCC PARIS agreement TRANSPARENCY Common but DIFFERENTIATED responsibilities and respective capabilities PRINCIPLE
下载PDF
Spatial and temporal variability of open biomass burning in Northeast China from 2003 to 2017 被引量:5
10
作者 WANG Lili JIN Xin +4 位作者 WANG Qinglu MAO Huiqin LIU Qiyang WENG Guoqing WANG Yuesi 《Atmospheric and Oceanic Science Letters》 CSCD 2020年第3期240-247,共8页
Open biomass burning(OBB)has a significant impact on the heavy haze pollution in Northeast China(NEC)in recent years,which requires the investigation of the spatiotemporal variations of OBB with different vegetation t... Open biomass burning(OBB)has a significant impact on the heavy haze pollution in Northeast China(NEC)in recent years,which requires the investigation of the spatiotemporal variations of OBB with different vegetation types to better monitor and control OBB in NEC.The MODIS C6 fire and land cover products,together with the emissions inventory from the Global Fire Assimilation System,were used in this study.The changes in the total number of MODIS fire points in NEC from 2003 to 2017 demonstrated a fluctuating but generally rising trend,with a peak during 2013–2017.Most fire points concentrated in two key periods,i.e.March–April(37%)and October–November(46%).The total number of crop residue burnings in March–April was basically slightly fluctuating and increased sharply from 2013,whilst the number in October–November had a fluctuating and upward trend until 2015,when a decline appeared.The amount of OBB in March–April was higher than that in October–November during 2016–17.OBB in Heilongjiang Province comprised a major proportion of all fires,which accounted for 70.7%from 2003 to 2017;however,the proportion was only 66.2%during 2013–2017.The largest proportion of all fires was in cropland(90.8%),then forest(5.3%)and grassland(3.1%).The cumulative emissions of fine particulate matter,nitrogen oxides,and ammonia from agricultural open burning in NEC reached 78.43 Gg,24.9 Gg,and 13.7 Gg for March–April during 2013–17,respectively,which were close to those in October–November. 展开更多
关键词 Open biomass burning MODIS Northeast China open agricultural residual burning
下载PDF
A glimpse into the biodiversity of insects in Yunnan: An updated and annotated checklist of butterflies(Lepidoptera, Papilionoidea) 被引量:4
11
作者 Tian-Tian Yu Zhou Chang +4 位作者 Zhi-Wei Dong Kai-Qin Li Fang-Zhou Ma Wen Wang Xue-Yan Li 《Zoological Research》 SCIE CAS CSCD 2022年第6期1009-1010,共2页
DEAR EDITOR, We provide an annotated checklist of the butterflies of Yunnan, which includes 356 genera and 1 300 species in six families. The number of butterfly genera and species in Yunnan accounts for 79.8% and 58.... DEAR EDITOR, We provide an annotated checklist of the butterflies of Yunnan, which includes 356 genera and 1 300 species in six families. The number of butterfly genera and species in Yunnan accounts for 79.8% and 58.6% of China’s total records, respectively. Thus, our study reveals that Yunnan has the highest butterfly diversity in China. This updated checklist also reports two genera and 18 species newly recorded from China as well as 36 species first recorded from Yunnan. 展开更多
关键词 BIODIVERSITY PAPILIO China
下载PDF
Ecological Risk Assessment of World Heritage Sites Using RS and GIS:A Case Study of Huangshan Mountain, China 被引量:2
12
作者 HUANG Shiman HU Qingwu +1 位作者 WANG Shaohua LI Haidong 《Chinese Geographical Science》 SCIE CSCD 2022年第5期808-823,共16页
Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical in... Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs. 展开更多
关键词 ecological risk assessment ecological risk index(ERI) world heritage site landscape ecological index Huangshan Mountain Remote Sensing
下载PDF
Sexual compatibility of transgenic soybean and different wild soybean populations 被引量:2
13
作者 HU Yu-qi SHENG Ze-wen +4 位作者 LIU Jin-yue LIU Qi QIANG Sheng SONG Xiao-ling LIU Biao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2022年第1期36-48,共13页
The introduction of genetically modified(GM) soybean into farming systems raises great concern that transgenes from GM soybean may flow to endemic wild soybean via pollen. This may increase the weediness of transgenic... The introduction of genetically modified(GM) soybean into farming systems raises great concern that transgenes from GM soybean may flow to endemic wild soybean via pollen. This may increase the weediness of transgenic soybean by increasing the fitness of hybrids under certain conditions and threaten the genetic diversity of wild soybean populations. Although pollen-mediated gene flow between GM crops and wild relatives is dependent on many factors, the sexual compatibility(SC)determined by their genetic backgrounds is the conclusive factor. The considerable genetic variation among wild soybean populations may cause compatibility differences between different wild and cultivated soybeans. Thus, an evaluation of the SC between transgenic soybean and different wild soybeans is essential for assessing the environmental consequences of cultivated soybean–wild soybean transgene flow. The podding and seed sets were assessed after artificial hybridization using transgenic glyphosate-resistant soybean as the paternal parent and 18 wild soybean populations as the maternal parents. Then, the average number of filled seeds produced in 200 flowers(AFS) was calculated for each wild soybean under natural self-pollination as well as under artificial crossing with transgenic soybean. Finally, the index of cross-SC was calculated(ICSC) as the ratio of the AFS of wild soybean artificially crossed with transgenic soybean and the AFS of naturally self-pollinated wild soybean. The results demonstrated that after self-pollination and crossing with transgenic soybean, the average podding rates of 18 wild soybean populations ranged within 96.50–99.50% and 4.92–18.03%, and the average filled seed numbers per pod varied from 1.70 to 2.69 and 0.20 to 0.48, respectively. The results showed that approximately 89% of wild soybeans displayed either medium or higher than medium SC with transgenic soybean(ICSC>1.0%). This implied the high possibility of gene flow via pollen from transgenic soybean to wild soybean. 展开更多
关键词 transgenic soybean wild soybean sexual compatibility artificial hybridization gene flow
下载PDF
Distribution characteristics and environmental risk assessment following metal(loid)s pollution incidents at Southwest China mining site 被引量:2
14
作者 Zhen-xing WANG Yun-jun YU +5 位作者 Tian-tian YE Jiang-chi FEI Xin-yu SONG Jian-wei PENG Yao-yu ZHOU Hong-hua WU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期4062-4075,共14页
Limited information is available on long-term effects of metal(loid)s pollution incidents. Here, we analyze the distribution characteristics and quantification of elements in the Southwest China Keda mining site, whic... Limited information is available on long-term effects of metal(loid)s pollution incidents. Here, we analyze the distribution characteristics and quantification of elements in the Southwest China Keda mining site, which is one of the most populated sites and enables human health and ecological risk assessments of elemental pollution. The results on modified degree of contamination indicated that the soil and sediment were highly contaminated near Dahu Lake.The health risk of children was almost 2.5 times that of adults in surface water, and 7.1 times in soil, respectively.Moreover, Tl and As were the main health risk contributors in surface water and soil, respectively, and As posed the highest ecological risk both in soil and sediment. These results indicated the potential impact of toxic metal(loid)s on the health of residents and environment. Hence, more scientific attention and proper management need to be paid to this environmental challenge in the future. 展开更多
关键词 THALLIUM ARSENIC mining site ecological risk health risk
下载PDF
Use of QSAR and SSD methods on deriving predicted no-effect concentrations in seawater and sediment for ten individual parent-and alkyl-PAHs and a case study on the assessment of their ecological risks from the Dalian Bay, China 被引量:2
15
作者 Ying Wang Xing Liu +6 位作者 Yi Cong Jin Fei Juying Wang Dian Zhang Liang Liu Jingli Mu Ziwei Yao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第12期95-105,共11页
Parent and alkylated polycyclic aromatic hydrocarbons(alkyl-PAHs),which are a class of important toxic components of crude oil especially in the marine environment,exhibit adverse effects on aquatic life and potential... Parent and alkylated polycyclic aromatic hydrocarbons(alkyl-PAHs),which are a class of important toxic components of crude oil especially in the marine environment,exhibit adverse effects on aquatic life and potentially pose a human health risk.However,the lack of chronic toxicity data is one of the hindrances for alkylPAHs when assessing their ecological risks.In this study,predicted no-effect concentrations(PNECs)in seawater and marine sediment for ten parent-and alkyl-PAHs were derived by applying species sensitivity distributions(SSDs)and quantitative structure-activity relationships(QSARs).The local area,Dalian Bay,where an oil-spilled accident happened in 2010,was chosen as a case site to assess ecological risks for ten PAHs in surface seawaters and marine sediments.Their PNECs in seawater and sediment for protecting aquatic organisms in marine ecosystems were calculated and recommended in the range of 0.012-2.79μg/L and 48.2-1337 ng/g(dry weight),respectively.Overall,the derived PNECs for the studied PAHs in seawater and marine sediment were comparable to those obtained by classical methods.Risk quotient results indicate low ecological risks to ecosystems for ten parent-and alkyl-PAHs in surface seawaters and surface sediments from the Dalian Bay.These findings provide a first insight into the PNECs and ecological risks of alkyl-PAHs,emphasizing the role of the computational toxicology in ecological risk assessments.The use of QSARs has been identified as a valuable tool for preliminarily assessing ecological risks of emerging pollutants,being more predictable of real exposure scenarios for risk assessment purposes. 展开更多
关键词 alkyl-PAHs QSARS PNECs ecological risks Dalian Bay
下载PDF
Surface metallization of PTFE and PTFE composites by ion implantation for low-background electronic substrates in rare-event detection experiments 被引量:2
16
作者 Shao-Jun Zhang Yuan-Yuan Liu +5 位作者 Sha-Sha Lv Jian-Ping Cheng Bin Liao Pan Pang Zhi Deng Li He 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第7期37-47,共11页
Polytetrafluoroethylene(PTFE)is a low-background polymer that is applied to several applications in rare-event detection and underground low-background experiments.PTFE-based electronic substrates are important for re... Polytetrafluoroethylene(PTFE)is a low-background polymer that is applied to several applications in rare-event detection and underground low-background experiments.PTFE-based electronic substrates are important for reducing the detection limit of high-purity germanium detectors and scintillator calorimeters,which are widely applied in dark matter and 0υββdetection experiments.The traditional adhesive bonding method between PTFE and copper is not conducive to working in liquid nitrogen and extremely low-temperature environments.To avoid adhesive bonding,PTFE must be processed for surface metallization owing to the mismatch between the PTFE and copper conductive layer.Low-background PTFE matrix composites(m-PTFE)were selected to improve the electrical and mechanical properties of PTFE by introducing SiO_(2)/TiO_(2) particles.The microstructures,surface elements,and electrical properties of PTFE and m-PTFE were characterized and analyzed following ion implantation.PTFE and m-PTFE surfaces were found to be broken,degraded,and cross-linked by ion implantation,resulting in C=C conjugated double bonds,increased surface energy,and increased surface roughness.Comparably,the surface roughness,bond strength,and conjugated double bonds of m-PTFE were significantly more intense than those of PTFE.Moreover,the interface bonding theory between PTFE and the metal copper foil was analyzed using the direct metallization principle.Therefore,the peel strength of the optimized electronic substrates was higher than that of the industrial standard at extremely low temperatures,while maintaining excellent electrical properties. 展开更多
关键词 Surface modification Polytetrafluoroethylene Ion implantation Surface metallization Low temperature resistance
下载PDF
Multidimensional diversity of bird communities across spatial variation of land cover in Zoige on the eastern Qinghai-Tibetan Plateau 被引量:2
17
作者 Aichun Xu Maojun Zhong +7 位作者 Ke Tang Xiaoyi Wang Chen Yang Haigen Xu Jianfeng Yi Wei Liu Chunlan Zhang Junhua Hu 《Avian Research》 CSCD 2021年第2期150-160,共11页
Background:Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization,whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to f... Background:Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization,whereby the increasing similarity would reduce the adaptive capacity of biotic assemblages to further disturbance,and degenerate ecosystem services they offer.However,it remains scarce to integrate multidimensional diversity for unveiling how variations in land cover may influence the patterns and processes of biotic homogeniza-tion in the Anthropocene.In this study,we examined how spatial variation of land cover could alter taxonomic,phy-logenetic and functional homogenization of bird communities simultaneously in a compound ecosystem of Zoige Marsh on the eastern Qinghai-Tibetan Plateau.Acting as the largest alpine marsh and peatland in the world,Zoige Marsh has undergone great changes in the land cover pattern due to climate change and anthropogenic activities.Methods:We conducted transect surveys for bird communities over six years(2014‒2019)during breeding sea-sons in four main land cover types(meadow,woodland,village and marsh),representing the spatial variation of land covers in the study area.We compared multidimensional diversity(taxonomic,phylogenetic and functional diver-sity)among land covers to assess the effects of spatial variation in land cover type on bird communities,particularly whether this variation has homogenized biotic communities.Results:Bird communities during breeding seasons were different and complementary in the four land covers.Taxonomic,phylogenetic and functional similarities were significantly lower in meadow than in the other three types,i.e.woodland,village and marsh.However,when we controlled for the effects of taxonomic similarities,the pattern of phylogenetic similarities almost reversed,with the highest standardized effect size(SES)phylogenetic similarity in meadow;and we found no significant difference in SES functional similarity among land covers.Conclusions:Our results suggest that spatial variation of land cover can play a crucial role in regulating multiple dimensions of bird diversity in Zoige Marsh.The findings indicate that taxonomic,phylogenetic and functional homogenization of bird communities may differently response to the variation of land covers.It thus highlights not only the relative roles of different land covers in maintaining biodiversity and community structures of birds,but also the urgency of retarding ecosystem degradations on the eastern Qinghai-Tibetan Plateau. 展开更多
关键词 Bird conservation Biotic homogenization Functional similarity Land cover types Phylogenetic similarity
下载PDF
A New Species of Trimeresurus Lacépède, 1804(Squamata: Viperidae) from Southwestern China, Vietnam, Thailand and Myanmar 被引量:1
18
作者 Zening CHEN Shengchao SHI +4 位作者 Jun GAO Gernot VOGEL Zhaobin SONG Li DING Rong DAI 《Asian Herpetological Research》 SCIE CSCD 2021年第2期167-177,共11页
The pit vipers of the genus Trimeresurus Lacépède, 1804 is one of the largest groups of Asian snakes, distributed from India to China and Indonesia. Recent surveys in Jiangcheng and Simao, Yunnan Province, C... The pit vipers of the genus Trimeresurus Lacépède, 1804 is one of the largest groups of Asian snakes, distributed from India to China and Indonesia. Recent surveys in Jiangcheng and Simao, Yunnan Province, China resulted in a new species previously allocated to T. albolabris. Combining morphological and molecular data, we describe it as Trimeresurus guoi sp. nov. The new species morphologically differs from T. albolabris in the yellow green ventral color;an indistinct ventrolateral line;the a bsence of a postocular stripe;the firebrickred iris;a dark red stripe on dorsal tail;hemipenes with relatively weak sparse papillae, reaching 23 rd subcaudal when unextruded. Molecularly, the new species forms a clearly divergent lineage(BPP 1.00/UFB 100). Uncorrected pairwise distances of mitochondrial gene Cyt b between the new species and other known species of the subgenus Trimeresurus range from 0.052(T. albolabris) to 0.071(T. insularis). 展开更多
关键词 morphology PHYLOGENETICS taxonomy TRIMERESURUS
下载PDF
Information standardization for typical toxic and harmful algae in China's coastal waters——a case study of Karenia mikimotoi 被引量:1
19
作者 Ting ZHAO Huidi CAO +3 位作者 Yanfen JIA Xiaotian HAN Tian YAN Rencheng YU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第6期2178-2188,共11页
To assist the researches of toxic and harmful algae and provide government workers with judgment basis for decision-making related events,we established a biological information management system for toxic and harmful... To assist the researches of toxic and harmful algae and provide government workers with judgment basis for decision-making related events,we established a biological information management system for toxic and harmful algae in China’s of fshore to assist relevant research.In this study,Karenia mikimotoi was studied as a typical toxic and harmful algae species,and the basic biological information and biogeographic distribution information of K.mikimotoi were systematically studied and collected.In the part of basic biological information,the name,toxin,and molecular characteristic sequence of K.mikimotoi were sorted out by literature searching and website browsing.Through experimental means,the relevant information of morphological identifi cation,pigment composition,and lipid composition were obtained.In the part of biogeographic distribution information,this study sorted out the information of K.mikimotoi,analyzed the characteristics of its occurrence,and completed the standardized construction of biogeographic distribution information.Through the collation of basic biological information and biogeographic distribution information of K.mikimotoi,the standardization of related information was completed,which provided template and method reference for information collection of other toxic and harmful algae species,which was benefi cial to the database analysis and design. 展开更多
关键词 harmful algae basic biological information biogeographic distribution information information standardization
下载PDF
Bridging gaps between environmental flows theory and practices in China 被引量:1
20
作者 Ang Chen Miao Wu +7 位作者 Sai-nan Wu Xin Sui Jing-ya Wen Peng-yuan Wang Lin Cheng Guy R.Lanza Chun-na Liu Wan-lin Jia 《Water Science and Engineering》 EI CAS CSCD 2019年第4期284-292,共9页
In recent decades,a series of policies and practices for environmental flows(e-flows)have been implemented in China,with the sustainable development goal of balancing the utilization and protection of water resources ... In recent decades,a series of policies and practices for environmental flows(e-flows)have been implemented in China,with the sustainable development goal of balancing the utilization and protection of water resources among social,economic,and ecological needs.The aims of this study were to determine the main challenges and issues in e-flows implementation at different scales by analyzing policies and practices for eflows in China,and to propose some recommendations for bridging the gaps between the science and implementation of e-flows.The gaps between the science and implementation of e-flows were found after review of literature,policies,and practices,and it was found that ecological flow was a more widely used term by the government,rather than e-flows,in implementation.The plans and effects of e-flows implementation are discussed in this paper and challenges of e-flows implementation are recognized:(1)limited water resources and uneven spatial and temporal distribution,(2)a weak scientific basis for e-flows implementation,(3)poor operability of e-flows science,and(4)ineffective supervision and guarantee measures.The recommendations are(1)to strengthen the scientific foundation of e-flows,(2)to improve effectiveness in application of e-flows science,and(3)to propose operable and effective supervision and guarantee measures.This paper elaborates the current understanding of e-flows science and provides practical recommendations for implementing e-flows and for improving the effectiveness in e-flows implementation.To bridge the gaps between science and implementation of e-flows and improve the operability of policies in future practices,more scientific research on practices is recommended through adaptive management. 展开更多
关键词 Environmental flows Ecological flow Integrated water resources management Adaptive management Sustainable development
下载PDF
上一页 1 2 10 下一页 到第
使用帮助 返回顶部