Marine protected areas(MPAs)across various countries have contributed to safeguarding coastal and marine environments.Despite these efforts,marine non-native species(NNS)continue to threaten biodiversity and ecosystem...Marine protected areas(MPAs)across various countries have contributed to safeguarding coastal and marine environments.Despite these efforts,marine non-native species(NNS)continue to threaten biodiversity and ecosystems,even within MPAs.Currently,there is a lack of comprehensive studies on the inventories,distribution patterns,and effect factors of NNS within MPAs.Here we show a database containing over 15,000 occurrence records of 2714 marine NNS across 16,401 national or regional MPAs worldwide.To identify the primary mechanisms driving the occurrence of NNS,we utilize model selection with proxies representing colonization pressure,environmental variables,and MPA characteristics.Among the environmental predictors analyzed,sea surface temperature emerged as the sole factor strongly associated with NNS richness.Higher sea surface temperatures are linked to increased NNS richness,aligning with global marine biodiversity trends.Furthermore,human activities help species overcome geographical barriers and migration constraints.Consequently,this influences the distribution patterns of marine introduced species and associated environmental factors.As global climate change continues to alter sea temperatures,it is crucial to protect marine regions that are increasingly vulnerable to intense human activities and biological invasions.展开更多
At 12:52 pm on September 5,2022,an Ms 6.8 earthquake occurred in Luding County,Sichuan Province,China.Based on high-resolution aerial photographs and satellite imageries obtained after the earthquake,as well as field ...At 12:52 pm on September 5,2022,an Ms 6.8 earthquake occurred in Luding County,Sichuan Province,China.Based on high-resolution aerial photographs and satellite imageries obtained after the earthquake,as well as field investigation,a total of 8685 earthquake-triggered landslides(EQTLs)were interpreted.The landslides covered an area of 30.7km^(2),with a source area of 9.4 km^(2).These EQTLs were mainly distributed in areas with a seismic intensity of VIII and IX.Most of the landslides were small and medium in size,and their types included landslide,rockfall,and rock slump.Characteristic landslide distributions were found,EQTLs were distributed along the Xianshuihe fault,landslide area decreased gradually with an increased distance to the fault;EQTLs were distributed along the Daduhe River and roads;besides,landslide distribution was associated with ground deformation caused by the earthquake.EQTLs’characteristics indicated that,a large number of EQTLs were located near the foot of the slope;the full area of EQTLs and their source area followed a power function.This study concluded that Luding EQTLs were greater in number and area but relatively smaller in terms of affected area.Investigations on geo-hazards post-earthquake and risk assessment were proposed in the earthquake-stricken area to support the rehabilitation and reconstruction.展开更多
The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previou...The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previous surveys,we found N.nomurai could not be observed in the south of 30°N.In this paper,we analyzed the mechanism of this phenomenon.After exploring the possible impacts of different environmental factors,we found that physical processes are essential to the distribution pattern of N.nomurai rather than biological or chemical factors in the East China Sea.The combination of the location of the initial breeding places of N.nomurai and the current system determine the distribution pattern.This study could provide important insights to the potential control of the giant jellyfish in the Chinese coastal waters.展开更多
The relationships of 42 species of ground moss with six environmental factors in 41 sites on Changbai Mountain Biosphere Reserve were analyzed. Four site groups and four groups of ground moss ecological species were i...The relationships of 42 species of ground moss with six environmental factors in 41 sites on Changbai Mountain Biosphere Reserve were analyzed. Four site groups and four groups of ground moss ecological species were identified using the method of Two-way Indicator Species Analysis (TWINSPAN). The results of Detrended Canonical. Correspondence Analysis (DCCA) showed that altitude, soil sand content, soil acidity, forest canopy coverage and soil water content are the five major environmental factors influencing the distributional patterns of the moss species. The four groups of ecological species, which correspond well with the four site groups, are projected on the species-environment biplot of DCCA. Group 1 dominated in the bogs of Larix olgensis forest, group 2 in the alpine tundra, group 3 in the dense conifer forest, and group 4 mainly in the Betula ermanii community and the Betula ermanii-Larix olgensis forest in sub-alpine respectively.展开更多
The distribution pattern of metals as active centers on a substrate can influence the peroxymonosulfate(PMS)activation and contaminants degradation.Herein,atomic layer deposition is applied to prepare Cu single atom(S...The distribution pattern of metals as active centers on a substrate can influence the peroxymonosulfate(PMS)activation and contaminants degradation.Herein,atomic layer deposition is applied to prepare Cu single atom(SA-Cu),cluster(C-Cu),and film(F-Cu)decorated MXene catalysts by regulating the number of deposition cycles.In comparison with SA-Cu-MXene(adsorption energy(E_(ads))=-4.236 eV)and F-Cu-MXene(E_(ads)=-3.548 eV),PMS is shown to adsorb preferably on the C-Cu-MXene surface for activation(E_(ads)=-5.435 eV),realizing higher utilization efficiency.More SO_(4)^(·-)are generated in C-Cu-MXene/PMS system with steady-state concentration and 1–3 orders of magnitude higher than those in the SA-Cu-MXene and F-Cu-MXene activated PMS systems.Particularly,the contribution of SO_(4)^(·-)oxidation to sulfamethoxazole(SMX)degradation followed the order,C-Cu-MXene(97.3%)>SA-Cu-MXene(90.4%)>FCu-MXene(71.9%),realizing the larger SMX degradation rate in the C-Cu-MXene/PMS system with the degradation rate constants(k)at 0.0485 min^(-1).Additionally,SMX degradation routes in C-Cu-MXene/PMS system are found with fewer toxic intermediates.Through this work,we highlighted the importance of guided design of heterogeneous catalysts in the PMS system.Appropriate metal distribution patterns need to be selected according to the actual water treatment demand.Metal sites could be then fully utilized to produce specific active species to improve the utilization efficiency of the oxidants.展开更多
The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation...The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis (DCCA) and the generalized additive model (GAM) methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe (2,200-2,300m), and in the alpine grassland region (2,900-3,100m), while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soft water, total nitroeen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.展开更多
Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of r...Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of rock masses in active fault zones which have been investigated previously are the key design basis for such projects.Therefore,a discrete element numerical model with different fault types,slip time,dip angles,and complex geological features was established,and then the creep slip for normal,reverse,and strike-slip faults were simulated to analyze the displacement distribution in the fault rock mass.A disk rotation test system and the corresponding laboratory test method were developed for simulating rock mass displacement induced by creep slippage of faults.A series of rotation tests for softand hard-layered specimens under combined compression and torsional stress were conducted to verify the numerical results and analyze the factors influencing the displacement distribution.An S-shaped displacement distribution independent of fault dip angle was identified corresponding to reverse,normal,and strike-slip faults.The results indicated that the higher the degree of horizontal extrusion,the softer the rock mass at the fault core,and the higher the degree of displacement concentration in the fault core;about 70%of the creep slip displacement occurs within this zone under 100 years of creep slippage.展开更多
The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment neces...The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment necessitates a systematic research on its patterns and impact factors to underpin the dynamics of problem as well as potential solutions. This paper took Wanzhou district in the central part of Three Gorges Reservoir Area as an example to study the spatial distribution patterns of abandoned farmland at three scales, i.e., town, village, and plot, and analyzed the influence from labor transfer and farmland circulation. We conducted a survey on the distribution patterns of abandoned farmland via questionnaires at town and village scales, together with the modeling and interpretation of high-resolution aerial images taken by unmanned aerial vehicles at plot scale. Our research discloses a strong relationship between the distribution of abandoned farmland and the distance from population center at different scales. At eithertown or village scale, the abandonment proportion was recognized the highest in mid-distance areas and lowest in close-distance areas, and the per capita area of abandoned farmland increased with the distance to downtown or township. At plot scale, abandonment proportion presented exponential growth with the distance to village center, whereas the abandoned farmland was mainly distributed in the areas with distance above 500 m from the village center. Moreover, we noticed that labor transfer and farmland circulation are two important factors that influence farmland abandonment. Labor's outbound transfer distance has a positive linkage with the possibility of farmland abandonment. Finally, it is recommended that development and adoption of corresponding policies on local urbanization and farmland circulation will facilitate to alleviate farmland abandonment.展开更多
Medicinal plants are the primary material basis for disease prevention and treatment in traditional Chinese medicine(TCM).The conservation and sustainable utilization of these medicinal plants is critical for the deve...Medicinal plants are the primary material basis for disease prevention and treatment in traditional Chinese medicine(TCM).The conservation and sustainable utilization of these medicinal plants is critical for the development of the TCM industry.However,wild medicinal plant resources have sharply declined in recent decades.To ameliorate the shortage of medicinal plant resources,it is essential to explore the development potential of the TCM industry in different geographical regions.For this purpose,we examined the spatial distribution of commonly used medicinal plants in China,the number of Chinese medicinal material markets,and the number of TCM decoction piece enterprises.Specifically,multispecies superimposition analysis and Thiessen polygons were used to reveal the optimal range for planting bulk medicinal plants and the ideal regions for building Chinese medicinal material markets,respectively.Furthermore,we quantitatively analyzed mismatches between the spatial distribution of commonly used medicinal plant richness,Chinese medicinal material markets,and TCM decoction piece enterprises.We found that the areas suitable for growing commonly used medicinal plants in China were mainly distributed in Hengduan Mountain,Nanling Mountain,Wuling Mountain,and Daba Mountain areas.The Thiessen polygon network based on Chinese medicinal material market localities showed there are currently fewer markets in southwestern,northwestern,and northeastern China than in central and southern China.TCM decoction piece enterprises are concentrated in a few provinces,such as Hebei and Jiangxi.We found that the distribution of commonly used medicinal plants,Chinese medicinal material markets and TCM decoction piece enterprises are mismatched in Henan,Shaanxi,Hunan,Hubei,Zhejiang,Fujian,Chongqing,and Xizang.We recommend strengthening development of the TCM industry in Henan,Hunan,Zhejiang,Shaanxi,Hubei,Chongqing,Fujian,and Xizang;building more Chinese medicinal material markets in southwestern,northwestern,and northeastern China;and establishing medicinal plant nurseries in resource-rich provinces to better protect and domesticate local medicinal plants.展开更多
Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankt...Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankton stock (Chl a concentration) and the impact of hydrological features such as water mass,mixing and tidal front on these patterns.The results indicated that the Chl a concentration was 2.43±2.64 (Mean ± SD) mg m-3 in April (range,0.35 to 17.02 mg m-3) and 1.75±3.10 mg m-3 in September (from 0.07 to 36.54 mg m-3) in 2003.Additionally,four areas with higher Chl a concentrations were observed in the surface water in April,while two were observed in September,and these areas were located within or near the point at which different water masses converged (temperature front area).The distribution pattern of Chl a was generally consistent between onshore and offshore stations at different depths in April and September.Specifically,higher Chl a concentrations were observed along the coastal line in September,which consisted of a mixing area and a tidal front area,although the distributional pattern of Chl a concentrations varied along transects in April.The maximum Chl a concentration at each station was observed in the surface and subsurface layer (0-10 m) for onshore stations and the thermocline layer (10-30 m) for offshore stations in September,while the greatest concentrations were generally observed in surface and subsurface water (0-10 m) in April.The formation of the Chl a distributional pattern in the SYS and NECS and its relationship with possible influencing factors is also discussed.Although physical forces had a close relationship with Chl a distribution,more data are required to clearly and comprehensively elucidate the spatial pattern dynamics of Chl a in the SYS and NECS.展开更多
Leaf area index (LAI) of natural vegetation is recognized as the most important variable for measuring vegetation structure over large areas, and for relating it to energy and mass exchange, which has been successfull...Leaf area index (LAI) of natural vegetation is recognized as the most important variable for measuring vegetation structure over large areas, and for relating it to energy and mass exchange, which has been successfully estimated from satellite resolution sensors. In this paper, according to the statistical analysis based on a lot of forest plots, the mathematical models of LAI distribution patterns in the hydro thermal spaces for five coniferous forest types in China were established. For the cold temperate larch forests growing in the dry and cold climate, their LAI increases with the increasing of warm index and precipitation in the way of hyperbolic quadratic surface. For the cold temperate spruce fir forests and temperate Pinus tabulaeformis forests, their LAI is negatively related to the annual mean air temperature in the way of the natural exponential curve, in order to adapt to the water oppressed environments. For the subtropical Pinus massoniana forests and Cunninghamia lanceolata forests growing in the warm and moist climate, their LAI is related to the annual mean air temperature in the way of the parabolic quadratic curve.展开更多
In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential ro...In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100~800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20~55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.展开更多
On the basis of the data of zooplankton biomass and three major taxa—— Copepoda, Chaetognatha andSiphonophora of May-June 1986, July-August and December 1987, the distributional patterns and the indicator species of...On the basis of the data of zooplankton biomass and three major taxa—— Copepoda, Chaetognatha andSiphonophora of May-June 1986, July-August and December 1987, the distributional patterns and the indicator species of zooplankton in the Kuroshio and adjacent waters of the East China Sea are preliminarily studied. The results are as follows:The horizontal distribution of zooplankton biomass and the abundance of copepods, chaetognaths and siphonophores arecurred in the continent area northwest of Taiwan and the south-centre section of the East China Sea continent, which are the mix front of different waters. Zooplankton in the water area inside of Ryukyu Islands presented low abundance and high diversity. There are clear seasonal variations in zooplankton biomass and abundance in the study area. The strength or weakness of different water masses and fronts is the basic reason for the variations of zooplankton biomass and abundance.The species composition of zooplankton in the study area is complex and varies, however, the tropic oceanic species predominates overwhelmingly. The distribution of different ecotype species evidences the distribution of different water masses and the state of mixture. The indicator species of each water mass are listed in the paper so as to provide grounds for the variation of currents in the Kuroshio area.The temperature and salinity of sea water are important factors affecting zooplankton distribution, composition and diversity , however the role of salinity is major. With the replacement of one season by another, the correlative levels of temperature and salinity to various zooplankton taxa are more or less significant.展开更多
As the city’s soft powef,culture is the basic core of urban competitiveness. The spatial concentration of cultufal facilities can show the development status of the dtfs cultural functions in the spatial ky...As the city’s soft powef,culture is the basic core of urban competitiveness. The spatial concentration of cultufal facilities can show the development status of the dtfs cultural functions in the spatial kyout. In this paper,POI data of Baidu Maps were used to conduct kernel density analysis and comprehensive evaluation of the spatial distribution of cultural facilities in Shenzhen; mean center point method was used to measure the degree of deviation between Shenzhen population centers and cultural facilities centers; the nearest distance method was used to measure the spatial distribution of cultural facilities space and the accessibility to geometdc centers of streets. The results showed that among the four types of cultural facilities in Shenzhen, librades were the most concentrated, accounting for 63% of the total number of cultural facilities, followed by cultxite and arts centers, museiims, and galleries; tiiere was a great disparity in the number of cultural facilities in various districts and subdistricts in Shenzhen, with a clear agglomeration effect in space; from the district level, cultural faculties spatially distributed from the southwest to the northeast by three gradients; from the street leviel, cultural facilities showed the distribution pattern of ^decreasing from west to eastf and a high d^tee of recognition for convenient transportation; the cultural facilities inside the Shenzhen Special Economic Zone (except Yantdan District) were more reasonable in spatial distribution, and the number of people served was more than that of cultural Realities outside the Shenzhen Special Economic Zone, while residents outside the Shenzhen Special Economic Zone enjoyed significantly more cultutal facilities than that inside the Shenzhen Special Economic Zone; the goal of the e£10-min cultutal dtdeJ, in Shenzhen had been initially completed, that is, residents could reach 72.41% of the streets with cultural facilities within a 10-min /raJk, but thefe were still 50% districts and 5.1% streets that wefe equipped with, unreasonably distributed cultufal facilities or few cultufal facilities.展开更多
There exist some controversies over the larger zoogeographic divisions of the arid areas of Central Asia, whose characteristics include complex ecological environments, complex fauna origins and unique patterns of ani...There exist some controversies over the larger zoogeographic divisions of the arid areas of Central Asia, whose characteristics include complex ecological environments, complex fauna origins and unique patterns of animal distribution. The aim of this study was to determine, using quantitative analysis, the distribution patterns of amphibians and reptiles in the arid areas of Central Asia, whose various physiographical regions were divided into 17 Operative Geographical Units (OGUs). Based on the presence or absence of 52 amphibian and reptile genera in the 17 OGUs, and by making use of the Czekanowski Similarity Index, the Baroni-Urbani and Buser's Similarity Index, and the strong and weak boundary test, we studied the biotic boundaries within these contested regions. In accordance with our results, the classification dendrogram was divided into two main branches. One branch is composed of the northern OGUs of the Altai Mountains which are a part of the Euro-Siberian Subrealm. The other branch includes all of the OGUs south of the Altai Mountains, which belong to the Central Asia Subrealm. There is a significantly weak biotic boundary (DW〉0, GW〉GS, P〈0.01) between the Euro-Siberian Subrealm and the Central Asia Subrealm that corre- sponded to the transitional zones. The boundary between the two subrealms runs along the Altai Mountains, the Sayan Mountains, the Hangai Mountains and the Mongolian Dagurr Mountains. The boundaries between the main branches in the Central Asia Subrealm are weak, reflecting the widespread existence of transitional zones in the arid areas of Central Asia. The Tianshan Mountains should be elevated to form its own separate region, "the Middle Asian Mountain Region", which, due to its special fauna and environment, would be classified at the same level as the Mongolia-Xinjiang Region. With the approach of creating a cluster analysis dendogram based upon the genera of amphibians and reptiles, the relationship of these higher level zoogeographical divisions was successfully resolved and the error of long-branch attraction was also avoided. With our clustering dendrogram as the foundation, the in- dependence test was applied to strong and weak boundaries, and this resolved the problem of where to attribute the transition areas and revealed as well the barrier effect that physical, geographic boundaries have upon amphibians and reptiles. The approach of combining genera clustering analysis with a statistical boundary test should be applicable not only to the distribution patterns of other animal groups, but also to delineating large-scale zoogeographical divisions.展开更多
An Acoustic Doppler Current Profiler (ADCP) observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters (SPM) distribution pattern. The SPM concentra...An Acoustic Doppler Current Profiler (ADCP) observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters (SPM) distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity (Sv), converted by the echo intensity (E/) of ADCP. Results show two types of SPM in the water column: the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is con- centrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM ir~ winter and sediments from Yellow Sea Mud Area (YSMA) in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.展开更多
Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construc...Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the展开更多
Calcite cements are volumetrically dominant among the most diagenetic constituents in turbidite sandstones of the Paleogene Shahejie Formation in the Dongying Depression.The results show carbonate cements mainly occur...Calcite cements are volumetrically dominant among the most diagenetic constituents in turbidite sandstones of the Paleogene Shahejie Formation in the Dongying Depression.The results show carbonate cements mainly occur in three phases:Calcite I(pre-compaction),Calcite II(post-compaction)and ankerite in the turbidite sandstone.The isotopic composition of Calcite I and Calcite II range from−4.3‰to 4.4‰,−3.5‰to 4.3‰PDB,respectively,suggesting that the calcite cements are mainly derived from the interbedded shales.The early calcite cement precipitated from the mixing of lacustrine and meteoric waters at 38-69℃.The late-phase calcite precipitated from pore waters modified by water-rock interactions at 64-126℃.Two distribution patterns of calcite cements can be identified,depending on their position within the sandstone.The peripheral cementation of the sandstones is near the sand-shale contact.The development of cement is controlled by sandstone thickness and the properties of the interbedded shale.For scattered cementation,the distribution of the calcite cement is not controlled by the sand-shale contact.Calcite cement was preferentially distributed in coarse-grained sandstones,indicating that sandstones with high original permeability are the preferred pathway for the migration of early diagenetic fluids.展开更多
Concentrations and distribution patterns of rare earth elements(REEs)in the intertidal flat of Tianjin were studied using P(507) resin and ICP-MS analytical technology. The results show that average concentrations of ...Concentrations and distribution patterns of rare earth elements(REEs)in the intertidal flat of Tianjin were studied using P(507) resin and ICP-MS analytical technology. The results show that average concentrations of REEs in the filtered(dissolved REEs), unfiltered and interstitial water are 0.461 μg·L^(-1), 4.98 μg·L^(-1) and 0.845 μg·L^(-1), respectively. Their distribution patterns are similar to those in inland natural rivers, but quite different from those in oceans. The average concentrations of REEs in sediments and suspended matters are 161.2 (mg·L^(-1)) and 168.1 mg·L^(-1), respectively, which are much lower than those in sediments of natural rivers but higher than those in sediments of the continental shelf of East China Sea. It is suggested that REEs in sediments and suspended matters of intertidal flat can have mainly originated from terrestrial soils and thus their transportation and transformation processes are similar with those in rivers, and different from those in continental shelves. Pollutants discharged into the Bohai Bay do·not cause significant effect on REEs in the intertidal flat of Tianjin yet.展开更多
This paper studied the biomass distribution patterns of Lanix olgensis/swamp ecotones and Betula platyphlla/swamp ecotones in Changbai Mountain so as to provide theory foundation for the management of these natur...This paper studied the biomass distribution patterns of Lanix olgensis/swamp ecotones and Betula platyphlla/swamp ecotones in Changbai Mountain so as to provide theory foundation for the management of these nature resources, by setting up sample belts, investigating initial data along the environmental gradients change, and establishing regression models. By means of regression models, the biomass of communities, layers, tree species and organs was calculated. In this system, it was found that the community biomass inreased gradually along the environmental gradients change from swamp to forest in Changbai Mountain. Furthermore, the ecotoneal biomass distributed mainly over tree layer. The tree biomass distributed mainly in two or three dominate tree species.展开更多
基金Second Tibetan Plateau Scientific Expedition and Research(STEP)program[grant number 2019QZKK0501]Third Xinjiang Scientific Expedition Program[grant number 2021xjkk0600]+1 种基金Biodiversity Survey,Monitoring and Assessment Project of Ministry of Ecology and Environment,China[grant number 2019HB2096001006]Fundamental Research Funds for the Central Public-interest Scientific Institution[grant number 2020YSKY-008].
文摘Marine protected areas(MPAs)across various countries have contributed to safeguarding coastal and marine environments.Despite these efforts,marine non-native species(NNS)continue to threaten biodiversity and ecosystems,even within MPAs.Currently,there is a lack of comprehensive studies on the inventories,distribution patterns,and effect factors of NNS within MPAs.Here we show a database containing over 15,000 occurrence records of 2714 marine NNS across 16,401 national or regional MPAs worldwide.To identify the primary mechanisms driving the occurrence of NNS,we utilize model selection with proxies representing colonization pressure,environmental variables,and MPA characteristics.Among the environmental predictors analyzed,sea surface temperature emerged as the sole factor strongly associated with NNS richness.Higher sea surface temperatures are linked to increased NNS richness,aligning with global marine biodiversity trends.Furthermore,human activities help species overcome geographical barriers and migration constraints.Consequently,this influences the distribution patterns of marine introduced species and associated environmental factors.As global climate change continues to alter sea temperatures,it is crucial to protect marine regions that are increasingly vulnerable to intense human activities and biological invasions.
基金supported by the“Second Tibetan Plateau Scientific Expedition and Research Program(STEP)”(Grant No.2019QZKK0902)the Strategic Priority Research Program of the CAS(No.XDA23090203)。
文摘At 12:52 pm on September 5,2022,an Ms 6.8 earthquake occurred in Luding County,Sichuan Province,China.Based on high-resolution aerial photographs and satellite imageries obtained after the earthquake,as well as field investigation,a total of 8685 earthquake-triggered landslides(EQTLs)were interpreted.The landslides covered an area of 30.7km^(2),with a source area of 9.4 km^(2).These EQTLs were mainly distributed in areas with a seismic intensity of VIII and IX.Most of the landslides were small and medium in size,and their types included landslide,rockfall,and rock slump.Characteristic landslide distributions were found,EQTLs were distributed along the Xianshuihe fault,landslide area decreased gradually with an increased distance to the fault;EQTLs were distributed along the Daduhe River and roads;besides,landslide distribution was associated with ground deformation caused by the earthquake.EQTLs’characteristics indicated that,a large number of EQTLs were located near the foot of the slope;the full area of EQTLs and their source area followed a power function.This study concluded that Luding EQTLs were greater in number and area but relatively smaller in terms of affected area.Investigations on geo-hazards post-earthquake and risk assessment were proposed in the earthquake-stricken area to support the rehabilitation and reconstruction.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA19060204,XDA23050502)the State Key Program of National Natural Science of China(No.42130411)+4 种基金the Key Deployment Project of Centre for Ocean Mega-Research of ScienceChinese Academy of Sciences(CAS)(No.COMS2019J03)the International Science Partnership Program of the Chinese Academy of Sciences(Nos.121311KYSB20190029,133137KYSB20200002)the Laoshan Laboratory(No.LSKJ202204005)the Aoshan Science and Technology Innovation Program(No.2016ASKJ02-4)。
文摘The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previous surveys,we found N.nomurai could not be observed in the south of 30°N.In this paper,we analyzed the mechanism of this phenomenon.After exploring the possible impacts of different environmental factors,we found that physical processes are essential to the distribution pattern of N.nomurai rather than biological or chemical factors in the East China Sea.The combination of the location of the initial breeding places of N.nomurai and the current system determine the distribution pattern.This study could provide important insights to the potential control of the giant jellyfish in the Chinese coastal waters.
文摘The relationships of 42 species of ground moss with six environmental factors in 41 sites on Changbai Mountain Biosphere Reserve were analyzed. Four site groups and four groups of ground moss ecological species were identified using the method of Two-way Indicator Species Analysis (TWINSPAN). The results of Detrended Canonical. Correspondence Analysis (DCCA) showed that altitude, soil sand content, soil acidity, forest canopy coverage and soil water content are the five major environmental factors influencing the distributional patterns of the moss species. The four groups of ecological species, which correspond well with the four site groups, are projected on the species-environment biplot of DCCA. Group 1 dominated in the bogs of Larix olgensis forest, group 2 in the alpine tundra, group 3 in the dense conifer forest, and group 4 mainly in the Betula ermanii community and the Betula ermanii-Larix olgensis forest in sub-alpine respectively.
基金the National Natural Science Foundation of China(52100156)the Natural Science Foundation of Tianjin(21JCQNJC00400)the Shenzhen Science and Technology Program(GJHZ20200731095801005 and JCYJ20200109150210400)for financial support to this research.
文摘The distribution pattern of metals as active centers on a substrate can influence the peroxymonosulfate(PMS)activation and contaminants degradation.Herein,atomic layer deposition is applied to prepare Cu single atom(SA-Cu),cluster(C-Cu),and film(F-Cu)decorated MXene catalysts by regulating the number of deposition cycles.In comparison with SA-Cu-MXene(adsorption energy(E_(ads))=-4.236 eV)and F-Cu-MXene(E_(ads)=-3.548 eV),PMS is shown to adsorb preferably on the C-Cu-MXene surface for activation(E_(ads)=-5.435 eV),realizing higher utilization efficiency.More SO_(4)^(·-)are generated in C-Cu-MXene/PMS system with steady-state concentration and 1–3 orders of magnitude higher than those in the SA-Cu-MXene and F-Cu-MXene activated PMS systems.Particularly,the contribution of SO_(4)^(·-)oxidation to sulfamethoxazole(SMX)degradation followed the order,C-Cu-MXene(97.3%)>SA-Cu-MXene(90.4%)>FCu-MXene(71.9%),realizing the larger SMX degradation rate in the C-Cu-MXene/PMS system with the degradation rate constants(k)at 0.0485 min^(-1).Additionally,SMX degradation routes in C-Cu-MXene/PMS system are found with fewer toxic intermediates.Through this work,we highlighted the importance of guided design of heterogeneous catalysts in the PMS system.Appropriate metal distribution patterns need to be selected according to the actual water treatment demand.Metal sites could be then fully utilized to produce specific active species to improve the utilization efficiency of the oxidants.
基金funded by the National Natural Science Foundation of China(Grant No.31360039)
文摘The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis (DCCA) and the generalized additive model (GAM) methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe (2,200-2,300m), and in the alpine grassland region (2,900-3,100m), while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soft water, total nitroeen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.
基金Project(U1865203)supported by the Key Projects of the Yalong River Joint Fund of the National Natural Science Foundation of ChinaProjects(41941018,51879135)supported by the National Natural Science Foundation of China。
文摘Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it.Displacement distribution patterns of rock masses in active fault zones which have been investigated previously are the key design basis for such projects.Therefore,a discrete element numerical model with different fault types,slip time,dip angles,and complex geological features was established,and then the creep slip for normal,reverse,and strike-slip faults were simulated to analyze the displacement distribution in the fault rock mass.A disk rotation test system and the corresponding laboratory test method were developed for simulating rock mass displacement induced by creep slippage of faults.A series of rotation tests for softand hard-layered specimens under combined compression and torsional stress were conducted to verify the numerical results and analyze the factors influencing the displacement distribution.An S-shaped displacement distribution independent of fault dip angle was identified corresponding to reverse,normal,and strike-slip faults.The results indicated that the higher the degree of horizontal extrusion,the softer the rock mass at the fault core,and the higher the degree of displacement concentration in the fault core;about 70%of the creep slip displacement occurs within this zone under 100 years of creep slippage.
基金supported by National Natural Science Foundation of China (Grant No. 41371539)Three Gorges Project Committee of the State Council research project: The ecological barrier area of Three Gorges Reservoir ecological benefits monitoring technology and assessment approach (Grant No. 0001792015CB5005)
文摘The severe farmland abandonment phenomena in China have tremendously decreased the farmland usage efficiency and caused a series of profound ecological and social outcomes. The complexity of farmland abandonment necessitates a systematic research on its patterns and impact factors to underpin the dynamics of problem as well as potential solutions. This paper took Wanzhou district in the central part of Three Gorges Reservoir Area as an example to study the spatial distribution patterns of abandoned farmland at three scales, i.e., town, village, and plot, and analyzed the influence from labor transfer and farmland circulation. We conducted a survey on the distribution patterns of abandoned farmland via questionnaires at town and village scales, together with the modeling and interpretation of high-resolution aerial images taken by unmanned aerial vehicles at plot scale. Our research discloses a strong relationship between the distribution of abandoned farmland and the distance from population center at different scales. At eithertown or village scale, the abandonment proportion was recognized the highest in mid-distance areas and lowest in close-distance areas, and the per capita area of abandoned farmland increased with the distance to downtown or township. At plot scale, abandonment proportion presented exponential growth with the distance to village center, whereas the abandoned farmland was mainly distributed in the areas with distance above 500 m from the village center. Moreover, we noticed that labor transfer and farmland circulation are two important factors that influence farmland abandonment. Labor's outbound transfer distance has a positive linkage with the possibility of farmland abandonment. Finally, it is recommended that development and adoption of corresponding policies on local urbanization and farmland circulation will facilitate to alleviate farmland abandonment.
基金funded by the National Natural Science Foundation of China(31800178)the Strategic Priority Research Programme of the Chinese Academy of Sciences(XDB31000000)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2021077).
文摘Medicinal plants are the primary material basis for disease prevention and treatment in traditional Chinese medicine(TCM).The conservation and sustainable utilization of these medicinal plants is critical for the development of the TCM industry.However,wild medicinal plant resources have sharply declined in recent decades.To ameliorate the shortage of medicinal plant resources,it is essential to explore the development potential of the TCM industry in different geographical regions.For this purpose,we examined the spatial distribution of commonly used medicinal plants in China,the number of Chinese medicinal material markets,and the number of TCM decoction piece enterprises.Specifically,multispecies superimposition analysis and Thiessen polygons were used to reveal the optimal range for planting bulk medicinal plants and the ideal regions for building Chinese medicinal material markets,respectively.Furthermore,we quantitatively analyzed mismatches between the spatial distribution of commonly used medicinal plant richness,Chinese medicinal material markets,and TCM decoction piece enterprises.We found that the areas suitable for growing commonly used medicinal plants in China were mainly distributed in Hengduan Mountain,Nanling Mountain,Wuling Mountain,and Daba Mountain areas.The Thiessen polygon network based on Chinese medicinal material market localities showed there are currently fewer markets in southwestern,northwestern,and northeastern China than in central and southern China.TCM decoction piece enterprises are concentrated in a few provinces,such as Hebei and Jiangxi.We found that the distribution of commonly used medicinal plants,Chinese medicinal material markets and TCM decoction piece enterprises are mismatched in Henan,Shaanxi,Hunan,Hubei,Zhejiang,Fujian,Chongqing,and Xizang.We recommend strengthening development of the TCM industry in Henan,Hunan,Zhejiang,Shaanxi,Hubei,Chongqing,Fujian,and Xizang;building more Chinese medicinal material markets in southwestern,northwestern,and northeastern China;and establishing medicinal plant nurseries in resource-rich provinces to better protect and domesticate local medicinal plants.
基金Supported by the National Natural Science Foundation of China (No.40606036)the National High Technology Research and Development Program (863 Program) (No.200lAA6360l0)the National Basic Research Program of China (973 Program) (No.2006CB400606)
文摘Two field studies were conducted to measure pigments in the Southern Yellow Sea (SYS) and the northern East China Sea (NECS) in April (spring) and September (autumn) to evaluate the distribution pattern of phytoplankton stock (Chl a concentration) and the impact of hydrological features such as water mass,mixing and tidal front on these patterns.The results indicated that the Chl a concentration was 2.43±2.64 (Mean ± SD) mg m-3 in April (range,0.35 to 17.02 mg m-3) and 1.75±3.10 mg m-3 in September (from 0.07 to 36.54 mg m-3) in 2003.Additionally,four areas with higher Chl a concentrations were observed in the surface water in April,while two were observed in September,and these areas were located within or near the point at which different water masses converged (temperature front area).The distribution pattern of Chl a was generally consistent between onshore and offshore stations at different depths in April and September.Specifically,higher Chl a concentrations were observed along the coastal line in September,which consisted of a mixing area and a tidal front area,although the distributional pattern of Chl a concentrations varied along transects in April.The maximum Chl a concentration at each station was observed in the surface and subsurface layer (0-10 m) for onshore stations and the thermocline layer (10-30 m) for offshore stations in September,while the greatest concentrations were generally observed in surface and subsurface water (0-10 m) in April.The formation of the Chl a distributional pattern in the SYS and NECS and its relationship with possible influencing factors is also discussed.Although physical forces had a close relationship with Chl a distribution,more data are required to clearly and comprehensively elucidate the spatial pattern dynamics of Chl a in the SYS and NECS.
文摘Leaf area index (LAI) of natural vegetation is recognized as the most important variable for measuring vegetation structure over large areas, and for relating it to energy and mass exchange, which has been successfully estimated from satellite resolution sensors. In this paper, according to the statistical analysis based on a lot of forest plots, the mathematical models of LAI distribution patterns in the hydro thermal spaces for five coniferous forest types in China were established. For the cold temperate larch forests growing in the dry and cold climate, their LAI increases with the increasing of warm index and precipitation in the way of hyperbolic quadratic surface. For the cold temperate spruce fir forests and temperate Pinus tabulaeformis forests, their LAI is negatively related to the annual mean air temperature in the way of the natural exponential curve, in order to adapt to the water oppressed environments. For the subtropical Pinus massoniana forests and Cunninghamia lanceolata forests growing in the warm and moist climate, their LAI is related to the annual mean air temperature in the way of the parabolic quadratic curve.
基金Financial support for this work,provided by the National Basic Research Program of China(No.2006 CB202300),
文摘In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100~800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20~55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.
文摘On the basis of the data of zooplankton biomass and three major taxa—— Copepoda, Chaetognatha andSiphonophora of May-June 1986, July-August and December 1987, the distributional patterns and the indicator species of zooplankton in the Kuroshio and adjacent waters of the East China Sea are preliminarily studied. The results are as follows:The horizontal distribution of zooplankton biomass and the abundance of copepods, chaetognaths and siphonophores arecurred in the continent area northwest of Taiwan and the south-centre section of the East China Sea continent, which are the mix front of different waters. Zooplankton in the water area inside of Ryukyu Islands presented low abundance and high diversity. There are clear seasonal variations in zooplankton biomass and abundance in the study area. The strength or weakness of different water masses and fronts is the basic reason for the variations of zooplankton biomass and abundance.The species composition of zooplankton in the study area is complex and varies, however, the tropic oceanic species predominates overwhelmingly. The distribution of different ecotype species evidences the distribution of different water masses and the state of mixture. The indicator species of each water mass are listed in the paper so as to provide grounds for the variation of currents in the Kuroshio area.The temperature and salinity of sea water are important factors affecting zooplankton distribution, composition and diversity , however the role of salinity is major. With the replacement of one season by another, the correlative levels of temperature and salinity to various zooplankton taxa are more or less significant.
文摘As the city’s soft powef,culture is the basic core of urban competitiveness. The spatial concentration of cultufal facilities can show the development status of the dtfs cultural functions in the spatial kyout. In this paper,POI data of Baidu Maps were used to conduct kernel density analysis and comprehensive evaluation of the spatial distribution of cultural facilities in Shenzhen; mean center point method was used to measure the degree of deviation between Shenzhen population centers and cultural facilities centers; the nearest distance method was used to measure the spatial distribution of cultural facilities space and the accessibility to geometdc centers of streets. The results showed that among the four types of cultural facilities in Shenzhen, librades were the most concentrated, accounting for 63% of the total number of cultural facilities, followed by cultxite and arts centers, museiims, and galleries; tiiere was a great disparity in the number of cultural facilities in various districts and subdistricts in Shenzhen, with a clear agglomeration effect in space; from the district level, cultural faculties spatially distributed from the southwest to the northeast by three gradients; from the street leviel, cultural facilities showed the distribution pattern of ^decreasing from west to eastf and a high d^tee of recognition for convenient transportation; the cultural facilities inside the Shenzhen Special Economic Zone (except Yantdan District) were more reasonable in spatial distribution, and the number of people served was more than that of cultural Realities outside the Shenzhen Special Economic Zone, while residents outside the Shenzhen Special Economic Zone enjoyed significantly more cultutal facilities than that inside the Shenzhen Special Economic Zone; the goal of the e£10-min cultutal dtdeJ, in Shenzhen had been initially completed, that is, residents could reach 72.41% of the streets with cultural facilities within a 10-min /raJk, but thefe were still 50% districts and 5.1% streets that wefe equipped with, unreasonably distributed cultufal facilities or few cultufal facilities.
基金supported by International Science & Technology Cooperation Program of China (2010DFA92720)the National Natural Science Foundation of China (31260511, 30360014)
文摘There exist some controversies over the larger zoogeographic divisions of the arid areas of Central Asia, whose characteristics include complex ecological environments, complex fauna origins and unique patterns of animal distribution. The aim of this study was to determine, using quantitative analysis, the distribution patterns of amphibians and reptiles in the arid areas of Central Asia, whose various physiographical regions were divided into 17 Operative Geographical Units (OGUs). Based on the presence or absence of 52 amphibian and reptile genera in the 17 OGUs, and by making use of the Czekanowski Similarity Index, the Baroni-Urbani and Buser's Similarity Index, and the strong and weak boundary test, we studied the biotic boundaries within these contested regions. In accordance with our results, the classification dendrogram was divided into two main branches. One branch is composed of the northern OGUs of the Altai Mountains which are a part of the Euro-Siberian Subrealm. The other branch includes all of the OGUs south of the Altai Mountains, which belong to the Central Asia Subrealm. There is a significantly weak biotic boundary (DW〉0, GW〉GS, P〈0.01) between the Euro-Siberian Subrealm and the Central Asia Subrealm that corre- sponded to the transitional zones. The boundary between the two subrealms runs along the Altai Mountains, the Sayan Mountains, the Hangai Mountains and the Mongolian Dagurr Mountains. The boundaries between the main branches in the Central Asia Subrealm are weak, reflecting the widespread existence of transitional zones in the arid areas of Central Asia. The Tianshan Mountains should be elevated to form its own separate region, "the Middle Asian Mountain Region", which, due to its special fauna and environment, would be classified at the same level as the Mongolia-Xinjiang Region. With the approach of creating a cluster analysis dendogram based upon the genera of amphibians and reptiles, the relationship of these higher level zoogeographical divisions was successfully resolved and the error of long-branch attraction was also avoided. With our clustering dendrogram as the foundation, the in- dependence test was applied to strong and weak boundaries, and this resolved the problem of where to attribute the transition areas and revealed as well the barrier effect that physical, geographic boundaries have upon amphibians and reptiles. The approach of combining genera clustering analysis with a statistical boundary test should be applicable not only to the distribution patterns of other animal groups, but also to delineating large-scale zoogeographical divisions.
基金supported by the National Natural Science Foundation of China (Grant No. 41030856)National 973 Project of China (Grant No. 2005CB422304)+1 种基金the Project of Taishan Scholarsupport of the R/V Dongfanghong 2 and Shared Voyage of the National Nature Science Foundation of China
文摘An Acoustic Doppler Current Profiler (ADCP) observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters (SPM) distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity (Sv), converted by the echo intensity (E/) of ADCP. Results show two types of SPM in the water column: the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is con- centrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM ir~ winter and sediments from Yellow Sea Mud Area (YSMA) in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.
基金co-supported by National Natural Science Foundation of China (Project number 41502201)"Western Light" project of Chinese Academy of Sciences (XBBS201301)
文摘Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the
基金funded by the National Natural Science Foundation of China (Grant No. 41572113)
文摘Calcite cements are volumetrically dominant among the most diagenetic constituents in turbidite sandstones of the Paleogene Shahejie Formation in the Dongying Depression.The results show carbonate cements mainly occur in three phases:Calcite I(pre-compaction),Calcite II(post-compaction)and ankerite in the turbidite sandstone.The isotopic composition of Calcite I and Calcite II range from−4.3‰to 4.4‰,−3.5‰to 4.3‰PDB,respectively,suggesting that the calcite cements are mainly derived from the interbedded shales.The early calcite cement precipitated from the mixing of lacustrine and meteoric waters at 38-69℃.The late-phase calcite precipitated from pore waters modified by water-rock interactions at 64-126℃.Two distribution patterns of calcite cements can be identified,depending on their position within the sandstone.The peripheral cementation of the sandstones is near the sand-shale contact.The development of cement is controlled by sandstone thickness and the properties of the interbedded shale.For scattered cementation,the distribution of the calcite cement is not controlled by the sand-shale contact.Calcite cement was preferentially distributed in coarse-grained sandstones,indicating that sandstones with high original permeability are the preferred pathway for the migration of early diagenetic fluids.
文摘Concentrations and distribution patterns of rare earth elements(REEs)in the intertidal flat of Tianjin were studied using P(507) resin and ICP-MS analytical technology. The results show that average concentrations of REEs in the filtered(dissolved REEs), unfiltered and interstitial water are 0.461 μg·L^(-1), 4.98 μg·L^(-1) and 0.845 μg·L^(-1), respectively. Their distribution patterns are similar to those in inland natural rivers, but quite different from those in oceans. The average concentrations of REEs in sediments and suspended matters are 161.2 (mg·L^(-1)) and 168.1 mg·L^(-1), respectively, which are much lower than those in sediments of natural rivers but higher than those in sediments of the continental shelf of East China Sea. It is suggested that REEs in sediments and suspended matters of intertidal flat can have mainly originated from terrestrial soils and thus their transportation and transformation processes are similar with those in rivers, and different from those in continental shelves. Pollutants discharged into the Bohai Bay do·not cause significant effect on REEs in the intertidal flat of Tianjin yet.
基金Chinese Academy of Sciences and National Education Committee
文摘This paper studied the biomass distribution patterns of Lanix olgensis/swamp ecotones and Betula platyphlla/swamp ecotones in Changbai Mountain so as to provide theory foundation for the management of these nature resources, by setting up sample belts, investigating initial data along the environmental gradients change, and establishing regression models. By means of regression models, the biomass of communities, layers, tree species and organs was calculated. In this system, it was found that the community biomass inreased gradually along the environmental gradients change from swamp to forest in Changbai Mountain. Furthermore, the ecotoneal biomass distributed mainly over tree layer. The tree biomass distributed mainly in two or three dominate tree species.