Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions ...Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.展开更多
Species richness in any area results from the interplay of the processes of speciation,extinction,and dispersal.The relationships between species richness and climate should be considered as an outcome of the effects ...Species richness in any area results from the interplay of the processes of speciation,extinction,and dispersal.The relationships between species richness and climate should be considered as an outcome of the effects of climate on speciation,extinction,and dispersal.Diversificationrate represents the balance of speciation and extinction rates over time.Here,I explore diversificationrates in mosses across geographic and climatic gradients worldwide.Specifically,I investigate latitudinal patterns and climatic associations of the mean diversificationrate of mosses at global,hemispheric,and smaller scales.I findthat the mean diversificationrate of mosses is positively correlated with species richness of mosses,increases with decreasing latitude and increasing mean annual temperature and annual precipitation,and is more strongly associated with mean annual temperature than with annual precipitation.These findingsshed light on variation of species richness in mosses across the world.The negative relationship between species richness and latitude and the positive relationship between species richness and mean diversificationrate in mosses suggest that higher moss species richness at lower latitudes might have resulted,at least to some degree,from higher moss diversificationrates at lower latitudes.展开更多
Latitudinal patterns of treeβ-diversity reveal important insights into the biogeographical processes that influence forest ecosystems.Although previous studies have extensively documentedβ-diversity within relativel...Latitudinal patterns of treeβ-diversity reveal important insights into the biogeographical processes that influence forest ecosystems.Although previous studies have extensively documentedβ-diversity within relatively small spatial extents,the potential drivers ofβ-diversity along latitudinal gradients are still not well understood at larger spatial extents.In this study,we determined whether treeβ-diversity is correlated with latitude in forests of southeastern China,and if so,what ecological processes contribute to these patterns of treeβ-diversity.We specifically aimed to disentangle the relative contributions from interspecific aggregation and environmental filtering across various spatial extents.We delineated regional communities comprising multiple nearby national forest inventory(NFI)plots around random focal plots.The number of NFI plots in a regional community served as a surrogate for spatial extent.We also used a null model to simulate randomly assembled communities and quantify the deviation(β-deviation)between observed and expectedβ-diversity.We found thatβ-diversity decreased along a latitudinal gradient and that this pattern was clearer at larger spatial extents.In addition,latitudinal patterns ofβ-deviation were explained by the degree of species spatial aggregation.We also identified environmental factors that driveβ-deviation in these forests,including precipitation,seasonality,and temperature variation.At larger spatial extents,these environmental variables explained up to 84%of theβ-deviation.Our results reinforce that ecological processes are scale-dependent and collectively contribute to theβ-gradient in subtropical forests.We recommend that conservation efforts maintain diverse forests and heterogeneous environments at multiple spatial extents to mitigate the adverse effects of climate change.展开更多
Soil enzymes activities and microbial biomass have an important influence on nutrient cycling. The spatial distribution of soil enzymes activities and microbial biomass were examined along a latitudinal gradient in fa...Soil enzymes activities and microbial biomass have an important influence on nutrient cycling. The spatial distribution of soil enzymes activities and microbial biomass were examined along a latitudinal gradient in farmlands of Songliao Plain, Northeast China to assess the impact of climatic changes along the latitudinal transect on nutrient cycling in agroecosystems. Top soils （0-20 cm depth） were sampled in fields at 7 locations from north （Hallun） to south （Dashiqiao） in the end of October 2005 after maize harvest. The contents of total C, N, and P, C/N, available N, and available P increased with the latitude. The activities of invertase and acid phosphatase, microbial biomass （MB） C and N, and MBC/MBN were significantly correlated with latitude （P 〈 0.05, r^2 = 0.198, 0.635, 0.558, 0.211 and 0.317, respectively）, that is, increasing with the latitude. Significant positive correlations （P 〈 0.05） were observed between invertase activity and the total N and available P, and between acid phosphatase activity and the total C, C/N, available N, total P and available P. The urease, acid phosphatase, and dehydrogenase activities were significantly correlated with the soil pH and electrical conductivity （EC） （P 〈 0.05）. MBC and MBN were positively correlated with the total C, C/N, and available P （P 〈 0.05）. The MBC/MBN ratio was positively correlated with the total C, total N, C/N, and available N （P 〈 0.05）. The spatial distribution of soil enzyme activities and microbial biomass resulted from the changes in soil properties such as soil organic matter, soil pH, and EC, partially owing to variations in temperature and rainfall along the latitudinal gradient.展开更多
Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific...Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific leaf area(SLA),and leaf dry matter content(LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China(NSTEC) between July and August 2013,and also calculated the community weighted means(CWM) of leaf traits by determining the relative dominance of each species.Our results showed that,for all species,the means(± SE) of LA,LT,SLA,and LDMC were 2860.01 ± 135.37 mm2,0.17 ± 0.003 mm,20.15 ± 0.43 m2 kg–1,and 316.73 ± 3.81 mg g–1,respectively.Furthermore,latitudinal variation in leaf traits differed at the species and community levels.Generally,at the species level,SLA increased and LDMC decreased as latitude increased,whereas no clear latitudinal trends among LA or LT were found,which could be the result of shifts in plant functional types.When scaling up to the community level,more significant spatial patterns of leaf traits were observed(R2 = 0.46–0.71),driven by climate and soil N content.These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future,and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.展开更多
Geographically,the Qinling-Daba Mountains serve as the main body of the north-south transitional zone of China.However,the transitional patterns of their plant species still need to be clarified.This study analyzed la...Geographically,the Qinling-Daba Mountains serve as the main body of the north-south transitional zone of China.However,the transitional patterns of their plant species still need to be clarified.This study analyzed latitudinal variations of plant species richness,relative importance values(RIV),and plant species abundance based on plant community field survey data for 163 sample sites along three north-south transect lines in the eastern,middle,and western parts of the study areas.The difference in RIV between subtropical and temperate species(SND-RIV)was selected to reveal the latitudinal interlacing pattern of northern and southern plant species.Along the eastern(Sanmenxia-Yichang),middle(Xi’an-Dazhou),and western(Tianshui-Guangyuan)transects,the richness and RIV of subtropical plant species increased while those of temperate plant species decreased from north to south.In the eastern transect,temperate plant species richness and RIV were the highest at Shennongjia and Funiu Mountain,respectively,because of their high elevations.In the middle transect,subtropical plant species richness and RIV were the highest in the Daba Mountains.In the western transect,richness and RIV were higher for subtropical than temperate plant species from the south of Longnan.The crisscrossing areas of northern and southern plant species were∼180 km,∼100 km,and∼60 km wide for the eastern,middle,and western transects,respectively,showing a narrowing trend from east to west.For the eastern and western transects,decreases in subtropical plant species distribution from south to north could be attributed to a decrease in mean annual precipitation in the same direction.However,for the middle transect,mean annual temperature had a slightly greater influence on plant species’latitudinal distribution than the moisture index.This study provides a more solid scientific basis for future investigations of this key geographical boundary in China.展开更多
Combined studies of latitudinal and interannual variations of annual phytoplankton bloom peak in East Asian marginal seas(17°–58°N, including the northern South China Sea(SCS), Kuroshio waters, the Sea of J...Combined studies of latitudinal and interannual variations of annual phytoplankton bloom peak in East Asian marginal seas(17°–58°N, including the northern South China Sea(SCS), Kuroshio waters, the Sea of Japan and the Okhotsk Sea) are rarely. Based on satellite-retrieved ten-year(2003–2012) median timing of the annual Chlorophyll a concentration(Chl a) climax, here we report that this annual spring bloom peak generally delays from the SCS in January to the Okhotsk Sea in June at a rate of(21.20±2.86) km/d(decadal median±SD). Spring bloom is dominant feature of the phytoplankton annual cycle over these regions, except for the SCS which features winter bloom. The fluctuation of the annual peak timing is mainly within ±48 d departured from the decadal median peak date, therefore this period(the decadal median peak date ±48 d) is defined as annual spring bloom period. As sea surface temperature rises, earlier spring bloom peak timing but decreasing averaged Chl a biomass in the spring bloom period due to insufficient light is evident in the Okhotsk Sea from 2003 to 2012. For the rest of three study domains, there are no significant interannual variance trend of the peak timing and the averaged Chl a biomass. Furthermore this change of spring phytoplankton bloom timing and magnitude in the Okhotsk Sea challenges previous prediction that ocean warming would enhance algal productivity at high latitudes.展开更多
During the 2nd Chinese Arctic Research Expedition, 20 pair of atmospheric samples were collected on the cruising route from Shanghai to Arctic Ocean using NOAA/ESRL flask sampling unit. Mean concentration of CO2 and C...During the 2nd Chinese Arctic Research Expedition, 20 pair of atmospheric samples were collected on the cruising route from Shanghai to Arctic Ocean using NOAA/ESRL flask sampling unit. Mean concentration of CO2 and CH4 were analyzed in different latitude zone from 30°N to 80°N and the distribution characteristics were studied. Mean concentration of CO2 decrease toward high latitude which indicates the uptake effect of CO2 by ocean. Coinciding with the CH4 global distribution character, mean CH4 concentration increase from 45°N to the North Pole region. Regional or local air mass may influence the greenhouse gas concentrations near seashore in the middle latitude （30°N-45°N）.展开更多
Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific...Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific tectonic system,the mid\|ocean ridge tectonic system and the intra\|continental tectonic system of the north hemisphere.The map shows that about 80% of the total length of the continental orogens are concentrate on the north hemisphere of the earth,of which a latitudinal mountain\|plateau chain occur within a zone between north latitude 20°and 50°.Seismic and volcanic activities demonstrate that the intracontinental tectonic system on the north hemisphere is still active.Whilst distribution of the continental deep\|focus earthquakes and almost ultra high\|pressure rock found so far over the World,that are assumed both related to recent or previous deep subduction of continent,along with this zone.The latitudinal mountain\|plateau chain is subdivided into four active tectonic region of Qinghai—Xizang(Tibet),Iranian,eastern mediterranean and North American,both characterized by an individual similar mountain\|plateau\|basin structure with major active boundaries or controlling faults (Fig.1).These active regions are all close to primary dynamic boundaries of continent\|continent collision.Solution of source mechanisms shows that regional tectonic stress field in these regions are dominated by a nearly NS or NNE—SSW direction compression corresponding to a local plate motions and a global compressive zone.Correlation between the formation of the continental latitudinal mountain\|plateau chain on north hemisphere and the oceanic plate tectonics is discussed using the information of the “Map of Magnetic Lineations of the World’s Ocean Basins (Cande et al.,1989)”and the Cenozoic and Mesozoic tectonic evolution in the continents.Total 49 accretion units formed during 6 accretion stages of the ocean spreading in three chief oceans (the Pacific,the India and the Atlantic)si nce 160Ma ago,are subdivided.The distinguished oceanic accretion tectonics in combination with the geometrical and kinematics data of adjust continental f ragments allowed outline of the development of the continental latitudinal tecto nic zone of north hemisphere.Whilst,two global asymmetrical geodynamic systems of north\|south an east\|west direction,that may be composed of meridional conve ction,latitudinal convection and inertial flow resulting from the variation of the Earth’s rotational velocity,are used to discuss on the two global geodynamic systems in which the intracontinental latitudinal tectonic zone developed.展开更多
Potassium(K),calcium(Ca),and magnesium(Mg)are essential elements with important physiological functions in plants.Previous studies showed that leaf K,Ca,and Mg concentrations generally increase with increasing latitud...Potassium(K),calcium(Ca),and magnesium(Mg)are essential elements with important physiological functions in plants.Previous studies showed that leaf K,Ca,and Mg concentrations generally increase with increasing latitudes.However,recent meta-analyses suggested the possibility of a unimodal pattern in the concentrations of these elements along latitudinal gradients.The authenticity of this unimodal latitudinal pattern,however,requires validation through large-scale field experimental data,and exploration of the underlying mechanisms if the pattern is confirmed.Here,we collected leaves of common species of woody plants from 19 montane forests in the north-south transect of eastern China,including 322 species from 160 genera,67 families;and then determined leaf K,Ca,and Mg concentrations to explore their latitudinal patterns and driving mechanisms.Our results support unimodal latitudinal patterns for all three elements in woody plants across eastern China,with peak values at latitude 36.5±1.0°N.The shift of plant-functional-type compositions from evergreen broadleaves to deciduous broadleaves and to conifers along this latitudinal span was the key factor contributing to these patterns.Climatic factors,mainly temperature,and to a lesser extent solar radiation and precipitation,were the main environmental drivers.These factors,by altering the composition of plant communities and regulating plant physiological activities,influence the latitudinal patterns of plant nutrient concentrations.Our findings also suggest that high leaf K,Ca,and Mg concentrations may represent an adaptive strategy for plants to withstand water stress,which might be used to predict plant nutrient responses to climate changes at large scales,and broaden the understanding of biogeochemical cycling of K,Ca,and Mg.展开更多
The implication of density in latitudinal correction to gravity measurement is investigated and the inner Iink of the density or the level ellipsoid with its latitude is also predicted. In this paper the density inte...The implication of density in latitudinal correction to gravity measurement is investigated and the inner Iink of the density or the level ellipsoid with its latitude is also predicted. In this paper the density integral formulae or gravity potential at pole and equator of the revolving ellipsoid are derived. In accordance with the gravity potential condition at pole and on equator of tbe level ellip soid, the Iatitudinal density distribution function of the level ellipsoid is given and further the hypothesis that radial aud longitudinal mean density of the earth normally distribute along latitudinal direction and its latitudinal density on the equator is larger than those at poles is put forward.展开更多
This paper presents an engineering system approach of 2-D cylindrical model of mass balance calculations with convection,diffusion,and all potential photolysis,ozone generating and depleting chemical reactions conside...This paper presents an engineering system approach of 2-D cylindrical model of mass balance calculations with convection,diffusion,and all potential photolysis,ozone generating and depleting chemical reactions considered.This model was developed,validated,and tested under different conditions for the stratospheric ozone.The calculated ozone concentrations and profile in the stratosphere at both the Equator and mid-latitudinal location of 40°S were found to exhibit a similar and close profile and peak value of the published measured data.The discrepancy between the calculations and measurements for the average ozone concentration was shown to be less than 1%and the variation of distributions to be less than 19%.The latitudinal changes of ozone concentrations,distribution,and peak of the layer were found to shift from 9.41 ppm at mid-altitude of z=30 km at the Equator,to 7.81 ppm at z=34.5 km at 40°S,to 5.78 ppm at higher altitude z=39 km at the South Pole.The total ozone abundances at strategic latitudes at 0°S,20°S,40°S,60°S,and 90°S,were found to remain stable and not much changed,from 305 DU to 335 DU,except a smaller value of 288 DU at the South Pole.The possible explanations of ozone profile change and peak shifting as affected by solar/UV radiation,latitudinal locations,and ozone-depleting reactions were discussed and elaborated.The 2-D ozone Model presented in this paper is a robust,efficient,executable,and validated model for studying the complex ozone phenomena in the stratosphere.展开更多
The Mesozoic—Cenozoic latitudinal displacement amounts of terranes (or blocks) in the Qinghai—Tibet plateau were calculated in paleomagnetism. These terranes (or blocks) include Tarim and Qaidam blocks, East Kunlun,...The Mesozoic—Cenozoic latitudinal displacement amounts of terranes (or blocks) in the Qinghai—Tibet plateau were calculated in paleomagnetism. These terranes (or blocks) include Tarim and Qaidam blocks, East Kunlun, Baryan Har, Qiangtang, Lhasa and Himalaya terranes. The calculated results are listed in table 1. These results show that:(1) There was the latitudinal displacement difference between central area and southwestern area in the Tarim southern margin since the lower Cretaceous. There was a southward latitudinal movement from the beginning of middle Jurassic or upper Jurassic (Zhou Qingjie, 1992). The northward movement amounts of the Tarim northern margin since the Paleocene are greater than that of the Tarim southern margin. Tarim southern margin has moved northward about 1100km since the Paleocene, Tarim northern margin has done about 1700km. Qaidam has moved northward about 3100km since lower\|middle Jurassic. The northward displacement amount of Qaidam since Paleocene is about 810km, near to that of the central area, Tarim southern margin.展开更多
The decrease in species richness toward higher latitudes is an expected biogeographical pattern.This pattern could be related to particular envi-ronmental constraints and the evolutionary history of clades.However,spe...The decrease in species richness toward higher latitudes is an expected biogeographical pattern.This pattern could be related to particular envi-ronmental constraints and the evolutionary history of clades.However,species richness does not fully represent the evolutionary history of the clades behind their distributions.Phylogenetic diversity better clarifies the role of historical factors in biogeographical patterns.We analyzed envi-ronmental and historical drivers related to latitudinal variation in species richness and phylogenetic diversity of Atlantic Forest endemic snakes.We implemented species distribution models,from voucherbased locality points,to map the snake ranges and diversity.We used generalized additive mixed models to evaluate the relationships among the diversity metrics and area,topographical roughness,and past climate change velocity since the Last Maximum Glacial in the Atlantic Forest latitudinal gradient.Contrary to the expected general pattern,species richness was higher toward higher latitudes,being positively related to past climatic stability.Species richness also increased with total area and higher topographical roughness.Phylogenetic diversity,on the other hand,showed opposite relationships related to the same factors.Phylogenetic diversity increased with lower climatic stability in lower latitudes.Thus,dimensions of diversity were affected in different ways by historical and environmental constraints in this unique and threatened biodiversity hotspot.展开更多
Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in ecology.This latitudinal diversity gradient has been observed in many major...Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in ecology.This latitudinal diversity gradient has been observed in many major groups of organisms.In plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and liverworts.However,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until now.Here,we analyze a comprehensive data set including moss species in each band of 20°in latitude worldwide.Our results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World)are considered separately.This result holds when variation in area size among latitudinal bands is taken into account.Pearson's correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern Hemispheres.Because bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.展开更多
Climate is a key factor to determine the pattern of ecosystems;however,the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas.The topography o...Climate is a key factor to determine the pattern of ecosystems;however,the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas.The topography of the dry valleys of southwestern China plays an important role in the formation of climate.However,its impact on the climate remains qualitative.In this study,eight climatic variables from 12 meteorological stations were analyzed to explore their latitudinal patterns in the wet and dry seasons from 1961 to 2019.We also quantified the effects of local topography(RH10)on the climatic variables.The results were as follows:sunshine duration,total solar radiation,average temperature,and evaporation decreased significantly,and wind speed increased significantly with increasing latitude in the annual,wet,and dry seasons(P<0.001).Relative humidity and precipitation decreased significantly with increasing latitude in the wet season(P<0.001),and no obvious change pattern was observed in the dry season.Aridity index significantly decreased(toward dryness)with increasing latitude in the wet season and increased in the dry season(P<0.001).Wind speed had a significantly positive relationship with topography(RH10)(P<0.01),whereas precipitation and aridity index were negatively associated with topography in the wet season and positively associated with topography in the dry season.Dryness was positively associated with RH10 in the wet season,and negatively in the dry season.The results of our research could provide new perspectives for understanding the relationship between topography and drought in the dry valleys of southwestern China.展开更多
Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density （PSD） of outer radiation belt energetic electrons was presented. We evaluate di...Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density （PSD） of outer radiation belt energetic electrons was presented. We evaluate diffusion rates in pitch angle and momentum due to a band of chorus frequency distributed at a standard Gaussian spectrum, and solve a 2-D bounce-averaged momentum-pitch-angle Fokker-Planck equation at L = 4.5. It is shown that chorus is effective in accelerating electrons and can increase PSD for energy of ～1 MeV by a factor of 10 or more in about one day, which is consistent with observation. Moreover, the latitudinal distribution of chorus has a great impact on the acceleration of electrons. As the latitudinal distribution increases, the efficient acceleration region extends from higher pitch angles to lower pitch angles, and even covers the entire pitch angle region when chorus power reaches the maximum latitude λm = 45°.展开更多
The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there...The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.展开更多
The Ordos Basin in the western part of the North China Craton is commonly believed to be a multi-controlled oil- bearing basin. It is bounded by the Xing＇an--Mongolian Orogen to the north, the Qingling Orogen to the ...The Ordos Basin in the western part of the North China Craton is commonly believed to be a multi-controlled oil- bearing basin. It is bounded by the Xing＇an--Mongolian Orogen to the north, the Qingling Orogen to the south, the Lüliang mountain to the east and the Helanshan--Liupanshan mountain belt to the west. The interpretation of geophysical data reveals a latitudinal （38°） fault belt in the centre of the Ordos Basin, which controls the hydrocarbon generation, migration and accumulation in the basin. This study attempts to investigate this belt from outcrops and indicates a structurally controlled system of migration fairway within the fault belt.展开更多
基金supported by the Fundamental Research Funds of Chinese Academy of Forestry(Nos.CAFYBB2022SY037,CAFYBB2021ZA002 and CAFYBB2022QC002)the Basic Research Foundation of Yunnan Province(Grant No.202201AT070264).
文摘Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.
文摘Species richness in any area results from the interplay of the processes of speciation,extinction,and dispersal.The relationships between species richness and climate should be considered as an outcome of the effects of climate on speciation,extinction,and dispersal.Diversificationrate represents the balance of speciation and extinction rates over time.Here,I explore diversificationrates in mosses across geographic and climatic gradients worldwide.Specifically,I investigate latitudinal patterns and climatic associations of the mean diversificationrate of mosses at global,hemispheric,and smaller scales.I findthat the mean diversificationrate of mosses is positively correlated with species richness of mosses,increases with decreasing latitude and increasing mean annual temperature and annual precipitation,and is more strongly associated with mean annual temperature than with annual precipitation.These findingsshed light on variation of species richness in mosses across the world.The negative relationship between species richness and latitude and the positive relationship between species richness and mean diversificationrate in mosses suggest that higher moss species richness at lower latitudes might have resulted,at least to some degree,from higher moss diversificationrates at lower latitudes.
基金supported by the National Natural Science Foundation of China(42271317)the Innovation Research Team Project of the Natural Science Foundation of Hainan Province(422CXTD515)。
文摘Latitudinal patterns of treeβ-diversity reveal important insights into the biogeographical processes that influence forest ecosystems.Although previous studies have extensively documentedβ-diversity within relatively small spatial extents,the potential drivers ofβ-diversity along latitudinal gradients are still not well understood at larger spatial extents.In this study,we determined whether treeβ-diversity is correlated with latitude in forests of southeastern China,and if so,what ecological processes contribute to these patterns of treeβ-diversity.We specifically aimed to disentangle the relative contributions from interspecific aggregation and environmental filtering across various spatial extents.We delineated regional communities comprising multiple nearby national forest inventory(NFI)plots around random focal plots.The number of NFI plots in a regional community served as a surrogate for spatial extent.We also used a null model to simulate randomly assembled communities and quantify the deviation(β-deviation)between observed and expectedβ-diversity.We found thatβ-diversity decreased along a latitudinal gradient and that this pattern was clearer at larger spatial extents.In addition,latitudinal patterns ofβ-deviation were explained by the degree of species spatial aggregation.We also identified environmental factors that driveβ-deviation in these forests,including precipitation,seasonality,and temperature variation.At larger spatial extents,these environmental variables explained up to 84%of theβ-deviation.Our results reinforce that ecological processes are scale-dependent and collectively contribute to theβ-gradient in subtropical forests.We recommend that conservation efforts maintain diverse forests and heterogeneous environments at multiple spatial extents to mitigate the adverse effects of climate change.
基金the National Key Basic Research Support Foundation of China (No.2005CB121105)theNational Natural Science Foundation of China (No.30670379).
文摘Soil enzymes activities and microbial biomass have an important influence on nutrient cycling. The spatial distribution of soil enzymes activities and microbial biomass were examined along a latitudinal gradient in farmlands of Songliao Plain, Northeast China to assess the impact of climatic changes along the latitudinal transect on nutrient cycling in agroecosystems. Top soils （0-20 cm depth） were sampled in fields at 7 locations from north （Hallun） to south （Dashiqiao） in the end of October 2005 after maize harvest. The contents of total C, N, and P, C/N, available N, and available P increased with the latitude. The activities of invertase and acid phosphatase, microbial biomass （MB） C and N, and MBC/MBN were significantly correlated with latitude （P 〈 0.05, r^2 = 0.198, 0.635, 0.558, 0.211 and 0.317, respectively）, that is, increasing with the latitude. Significant positive correlations （P 〈 0.05） were observed between invertase activity and the total N and available P, and between acid phosphatase activity and the total C, C/N, available N, total P and available P. The urease, acid phosphatase, and dehydrogenase activities were significantly correlated with the soil pH and electrical conductivity （EC） （P 〈 0.05）. MBC and MBN were positively correlated with the total C, C/N, and available P （P 〈 0.05）. The MBC/MBN ratio was positively correlated with the total C, total N, C/N, and available N （P 〈 0.05）. The spatial distribution of soil enzyme activities and microbial biomass resulted from the changes in soil properties such as soil organic matter, soil pH, and EC, partially owing to variations in temperature and rainfall along the latitudinal gradient.
基金National Natural Science Foundation of China,No.31290221,No.31470506Chinese Academy of Sciences Strategic Priority Research Program,No.XDA05050702Program for Kezhen Distinguished Talents in Institute of Geographic Sciences and Natural Resources Research,CAS,No.2013RC102
文摘Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific leaf area(SLA),and leaf dry matter content(LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China(NSTEC) between July and August 2013,and also calculated the community weighted means(CWM) of leaf traits by determining the relative dominance of each species.Our results showed that,for all species,the means(± SE) of LA,LT,SLA,and LDMC were 2860.01 ± 135.37 mm2,0.17 ± 0.003 mm,20.15 ± 0.43 m2 kg–1,and 316.73 ± 3.81 mg g–1,respectively.Furthermore,latitudinal variation in leaf traits differed at the species and community levels.Generally,at the species level,SLA increased and LDMC decreased as latitude increased,whereas no clear latitudinal trends among LA or LT were found,which could be the result of shifts in plant functional types.When scaling up to the community level,more significant spatial patterns of leaf traits were observed(R2 = 0.46–0.71),driven by climate and soil N content.These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future,and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.
基金National Scientific and Technological Basic Resources Investigation Project,No.2017FY100900。
文摘Geographically,the Qinling-Daba Mountains serve as the main body of the north-south transitional zone of China.However,the transitional patterns of their plant species still need to be clarified.This study analyzed latitudinal variations of plant species richness,relative importance values(RIV),and plant species abundance based on plant community field survey data for 163 sample sites along three north-south transect lines in the eastern,middle,and western parts of the study areas.The difference in RIV between subtropical and temperate species(SND-RIV)was selected to reveal the latitudinal interlacing pattern of northern and southern plant species.Along the eastern(Sanmenxia-Yichang),middle(Xi’an-Dazhou),and western(Tianshui-Guangyuan)transects,the richness and RIV of subtropical plant species increased while those of temperate plant species decreased from north to south.In the eastern transect,temperate plant species richness and RIV were the highest at Shennongjia and Funiu Mountain,respectively,because of their high elevations.In the middle transect,subtropical plant species richness and RIV were the highest in the Daba Mountains.In the western transect,richness and RIV were higher for subtropical than temperate plant species from the south of Longnan.The crisscrossing areas of northern and southern plant species were∼180 km,∼100 km,and∼60 km wide for the eastern,middle,and western transects,respectively,showing a narrowing trend from east to west.For the eastern and western transects,decreases in subtropical plant species distribution from south to north could be attributed to a decrease in mean annual precipitation in the same direction.However,for the middle transect,mean annual temperature had a slightly greater influence on plant species’latitudinal distribution than the moisture index.This study provides a more solid scientific basis for future investigations of this key geographical boundary in China.
基金The scientific research fund of the Second Institute of Oceanography,State Oceanic Administration,China under contract No.JG1417the Public Science and Technology Research Funds Projects of Ocean under contract No.201005030the National Natural Science Foundation of China under contract Nos 41476156 and 41321004
文摘Combined studies of latitudinal and interannual variations of annual phytoplankton bloom peak in East Asian marginal seas(17°–58°N, including the northern South China Sea(SCS), Kuroshio waters, the Sea of Japan and the Okhotsk Sea) are rarely. Based on satellite-retrieved ten-year(2003–2012) median timing of the annual Chlorophyll a concentration(Chl a) climax, here we report that this annual spring bloom peak generally delays from the SCS in January to the Okhotsk Sea in June at a rate of(21.20±2.86) km/d(decadal median±SD). Spring bloom is dominant feature of the phytoplankton annual cycle over these regions, except for the SCS which features winter bloom. The fluctuation of the annual peak timing is mainly within ±48 d departured from the decadal median peak date, therefore this period(the decadal median peak date ±48 d) is defined as annual spring bloom period. As sea surface temperature rises, earlier spring bloom peak timing but decreasing averaged Chl a biomass in the spring bloom period due to insufficient light is evident in the Okhotsk Sea from 2003 to 2012. For the rest of three study domains, there are no significant interannual variance trend of the peak timing and the averaged Chl a biomass. Furthermore this change of spring phytoplankton bloom timing and magnitude in the Okhotsk Sea challenges previous prediction that ocean warming would enhance algal productivity at high latitudes.
文摘During the 2nd Chinese Arctic Research Expedition, 20 pair of atmospheric samples were collected on the cruising route from Shanghai to Arctic Ocean using NOAA/ESRL flask sampling unit. Mean concentration of CO2 and CH4 were analyzed in different latitude zone from 30°N to 80°N and the distribution characteristics were studied. Mean concentration of CO2 decrease toward high latitude which indicates the uptake effect of CO2 by ocean. Coinciding with the CH4 global distribution character, mean CH4 concentration increase from 45°N to the North Pole region. Regional or local air mass may influence the greenhouse gas concentrations near seashore in the middle latitude （30°N-45°N）.
文摘Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific tectonic system,the mid\|ocean ridge tectonic system and the intra\|continental tectonic system of the north hemisphere.The map shows that about 80% of the total length of the continental orogens are concentrate on the north hemisphere of the earth,of which a latitudinal mountain\|plateau chain occur within a zone between north latitude 20°and 50°.Seismic and volcanic activities demonstrate that the intracontinental tectonic system on the north hemisphere is still active.Whilst distribution of the continental deep\|focus earthquakes and almost ultra high\|pressure rock found so far over the World,that are assumed both related to recent or previous deep subduction of continent,along with this zone.The latitudinal mountain\|plateau chain is subdivided into four active tectonic region of Qinghai—Xizang(Tibet),Iranian,eastern mediterranean and North American,both characterized by an individual similar mountain\|plateau\|basin structure with major active boundaries or controlling faults (Fig.1).These active regions are all close to primary dynamic boundaries of continent\|continent collision.Solution of source mechanisms shows that regional tectonic stress field in these regions are dominated by a nearly NS or NNE—SSW direction compression corresponding to a local plate motions and a global compressive zone.Correlation between the formation of the continental latitudinal mountain\|plateau chain on north hemisphere and the oceanic plate tectonics is discussed using the information of the “Map of Magnetic Lineations of the World’s Ocean Basins (Cande et al.,1989)”and the Cenozoic and Mesozoic tectonic evolution in the continents.Total 49 accretion units formed during 6 accretion stages of the ocean spreading in three chief oceans (the Pacific,the India and the Atlantic)si nce 160Ma ago,are subdivided.The distinguished oceanic accretion tectonics in combination with the geometrical and kinematics data of adjust continental f ragments allowed outline of the development of the continental latitudinal tecto nic zone of north hemisphere.Whilst,two global asymmetrical geodynamic systems of north\|south an east\|west direction,that may be composed of meridional conve ction,latitudinal convection and inertial flow resulting from the variation of the Earth’s rotational velocity,are used to discuss on the two global geodynamic systems in which the intracontinental latitudinal tectonic zone developed.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA26040202)the National Natural Science Foundation of China(41173083)+1 种基金SL was also supported by the National Natural Science Foundation of China(32001165)the Natural Science Foundation of Sichuan Province(2022NSFSC1753)。
文摘Potassium(K),calcium(Ca),and magnesium(Mg)are essential elements with important physiological functions in plants.Previous studies showed that leaf K,Ca,and Mg concentrations generally increase with increasing latitudes.However,recent meta-analyses suggested the possibility of a unimodal pattern in the concentrations of these elements along latitudinal gradients.The authenticity of this unimodal latitudinal pattern,however,requires validation through large-scale field experimental data,and exploration of the underlying mechanisms if the pattern is confirmed.Here,we collected leaves of common species of woody plants from 19 montane forests in the north-south transect of eastern China,including 322 species from 160 genera,67 families;and then determined leaf K,Ca,and Mg concentrations to explore their latitudinal patterns and driving mechanisms.Our results support unimodal latitudinal patterns for all three elements in woody plants across eastern China,with peak values at latitude 36.5±1.0°N.The shift of plant-functional-type compositions from evergreen broadleaves to deciduous broadleaves and to conifers along this latitudinal span was the key factor contributing to these patterns.Climatic factors,mainly temperature,and to a lesser extent solar radiation and precipitation,were the main environmental drivers.These factors,by altering the composition of plant communities and regulating plant physiological activities,influence the latitudinal patterns of plant nutrient concentrations.Our findings also suggest that high leaf K,Ca,and Mg concentrations may represent an adaptive strategy for plants to withstand water stress,which might be used to predict plant nutrient responses to climate changes at large scales,and broaden the understanding of biogeochemical cycling of K,Ca,and Mg.
文摘The implication of density in latitudinal correction to gravity measurement is investigated and the inner Iink of the density or the level ellipsoid with its latitude is also predicted. In this paper the density integral formulae or gravity potential at pole and equator of the revolving ellipsoid are derived. In accordance with the gravity potential condition at pole and on equator of tbe level ellip soid, the Iatitudinal density distribution function of the level ellipsoid is given and further the hypothesis that radial aud longitudinal mean density of the earth normally distribute along latitudinal direction and its latitudinal density on the equator is larger than those at poles is put forward.
文摘This paper presents an engineering system approach of 2-D cylindrical model of mass balance calculations with convection,diffusion,and all potential photolysis,ozone generating and depleting chemical reactions considered.This model was developed,validated,and tested under different conditions for the stratospheric ozone.The calculated ozone concentrations and profile in the stratosphere at both the Equator and mid-latitudinal location of 40°S were found to exhibit a similar and close profile and peak value of the published measured data.The discrepancy between the calculations and measurements for the average ozone concentration was shown to be less than 1%and the variation of distributions to be less than 19%.The latitudinal changes of ozone concentrations,distribution,and peak of the layer were found to shift from 9.41 ppm at mid-altitude of z=30 km at the Equator,to 7.81 ppm at z=34.5 km at 40°S,to 5.78 ppm at higher altitude z=39 km at the South Pole.The total ozone abundances at strategic latitudes at 0°S,20°S,40°S,60°S,and 90°S,were found to remain stable and not much changed,from 305 DU to 335 DU,except a smaller value of 288 DU at the South Pole.The possible explanations of ozone profile change and peak shifting as affected by solar/UV radiation,latitudinal locations,and ozone-depleting reactions were discussed and elaborated.The 2-D ozone Model presented in this paper is a robust,efficient,executable,and validated model for studying the complex ozone phenomena in the stratosphere.
文摘The Mesozoic—Cenozoic latitudinal displacement amounts of terranes (or blocks) in the Qinghai—Tibet plateau were calculated in paleomagnetism. These terranes (or blocks) include Tarim and Qaidam blocks, East Kunlun, Baryan Har, Qiangtang, Lhasa and Himalaya terranes. The calculated results are listed in table 1. These results show that:(1) There was the latitudinal displacement difference between central area and southwestern area in the Tarim southern margin since the lower Cretaceous. There was a southward latitudinal movement from the beginning of middle Jurassic or upper Jurassic (Zhou Qingjie, 1992). The northward movement amounts of the Tarim northern margin since the Paleocene are greater than that of the Tarim southern margin. Tarim southern margin has moved northward about 1100km since the Paleocene, Tarim northern margin has done about 1700km. Qaidam has moved northward about 3100km since lower\|middle Jurassic. The northward displacement amount of Qaidam since Paleocene is about 810km, near to that of the central area, Tarim southern margin.
基金supported by grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo(FAPESP 2014/23677-9 and 2020/12658-4)Conselho Nacional de Desenvolvimento Cientifico e Tecnol6gico(CNPq,405447/2016-7).R.J.S.thanks CNPq for the research fellowship(307956/2022-9).J.A.R.A.thanks Instituto Serrapilheira for the postdoctoral fellowship.
文摘The decrease in species richness toward higher latitudes is an expected biogeographical pattern.This pattern could be related to particular envi-ronmental constraints and the evolutionary history of clades.However,species richness does not fully represent the evolutionary history of the clades behind their distributions.Phylogenetic diversity better clarifies the role of historical factors in biogeographical patterns.We analyzed envi-ronmental and historical drivers related to latitudinal variation in species richness and phylogenetic diversity of Atlantic Forest endemic snakes.We implemented species distribution models,from voucherbased locality points,to map the snake ranges and diversity.We used generalized additive mixed models to evaluate the relationships among the diversity metrics and area,topographical roughness,and past climate change velocity since the Last Maximum Glacial in the Atlantic Forest latitudinal gradient.Contrary to the expected general pattern,species richness was higher toward higher latitudes,being positively related to past climatic stability.Species richness also increased with total area and higher topographical roughness.Phylogenetic diversity,on the other hand,showed opposite relationships related to the same factors.Phylogenetic diversity increased with lower climatic stability in lower latitudes.Thus,dimensions of diversity were affected in different ways by historical and environmental constraints in this unique and threatened biodiversity hotspot.
文摘Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in ecology.This latitudinal diversity gradient has been observed in many major groups of organisms.In plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and liverworts.However,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until now.Here,we analyze a comprehensive data set including moss species in each band of 20°in latitude worldwide.Our results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World)are considered separately.This result holds when variation in area size among latitudinal bands is taken into account.Pearson's correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern Hemispheres.Because bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.
基金supported by the National Key Research and Development Program of China(2017YFC0505105)。
文摘Climate is a key factor to determine the pattern of ecosystems;however,the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas.The topography of the dry valleys of southwestern China plays an important role in the formation of climate.However,its impact on the climate remains qualitative.In this study,eight climatic variables from 12 meteorological stations were analyzed to explore their latitudinal patterns in the wet and dry seasons from 1961 to 2019.We also quantified the effects of local topography(RH10)on the climatic variables.The results were as follows:sunshine duration,total solar radiation,average temperature,and evaporation decreased significantly,and wind speed increased significantly with increasing latitude in the annual,wet,and dry seasons(P<0.001).Relative humidity and precipitation decreased significantly with increasing latitude in the wet season(P<0.001),and no obvious change pattern was observed in the dry season.Aridity index significantly decreased(toward dryness)with increasing latitude in the wet season and increased in the dry season(P<0.001).Wind speed had a significantly positive relationship with topography(RH10)(P<0.01),whereas precipitation and aridity index were negatively associated with topography in the wet season and positively associated with topography in the dry season.Dryness was positively associated with RH10 in the wet season,and negatively in the dry season.The results of our research could provide new perspectives for understanding the relationship between topography and drought in the dry valleys of southwestern China.
基金National Natural Science Foundation of China (Nos.40774078,40774079 and 40874076)the Special Fund for Public Welfare Industry of China (Meteorology)CYHY200806024the Visiting Scholar Foundation of State Key Laboratory for Space Weather,CAS
文摘Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density （PSD） of outer radiation belt energetic electrons was presented. We evaluate diffusion rates in pitch angle and momentum due to a band of chorus frequency distributed at a standard Gaussian spectrum, and solve a 2-D bounce-averaged momentum-pitch-angle Fokker-Planck equation at L = 4.5. It is shown that chorus is effective in accelerating electrons and can increase PSD for energy of ～1 MeV by a factor of 10 or more in about one day, which is consistent with observation. Moreover, the latitudinal distribution of chorus has a great impact on the acceleration of electrons. As the latitudinal distribution increases, the efficient acceleration region extends from higher pitch angles to lower pitch angles, and even covers the entire pitch angle region when chorus power reaches the maximum latitude λm = 45°.
文摘The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.
文摘The Ordos Basin in the western part of the North China Craton is commonly believed to be a multi-controlled oil- bearing basin. It is bounded by the Xing＇an--Mongolian Orogen to the north, the Qingling Orogen to the south, the Lüliang mountain to the east and the Helanshan--Liupanshan mountain belt to the west. The interpretation of geophysical data reveals a latitudinal （38°） fault belt in the centre of the Ordos Basin, which controls the hydrocarbon generation, migration and accumulation in the basin. This study attempts to investigate this belt from outcrops and indicates a structurally controlled system of migration fairway within the fault belt.
