Predicting the potential geographic distribution of Bactrocera bryoniae and Bactrocera neohumeralis(Diptera: Tephritidae) in China using MaxEnt ecological niche modeling

Bactrocera bryoniae and Bactrocera neohumeralis are highly destructive and major biosecurity/quarantine pests of fruit and vegetable in the tropical and subtropical regions in the South Pacific and Australia.Although these pests have not established in China,precautions must be taken due to their highly destructive nature.Thus,we predicted the potential geographic distribution of B.bryoniae and B.neohumeralis across the world and in particular China by ecological niche modeling of the Maximum Entropy(Max Ent)model with the occurrence records of these two species.Bactrocera bryoniae and B.neohumeralis exhibit similar potential geographic distribution ranges across the world and in China,and each species was predicted to be able to distribute to over 20%of the globe.Globally,the potential geographic distribution ranges for these two fruit fly species included southern Asia,the central and the southeast coast of Africa,southern North America,northern and central South America,and Australia.While within China,most of the southern Yangtze River area was found suitable for these species.Notably,southern China was considered to have the highest risk of B.bryoniae and B.neohumeralis invasions.Our study identifies the regions at high risk for potential establishment of B.bryoniae and B.neohumeralis in the world and in particular China,and informs the development of inspection and biosecurity/quarantine measures to prevent and control their invasions.

Geographic Distribution of Mating Types in Magnaporthe grisea and the Relationship Between Fertile Isolates in China

377 isolates of Magnaporthe grisea were collected from 17 provinces in China and their geographic distribution of mating types and their fertility was tested with four standard isolates, KA3 and TH12 (Mat1.1) and Guy11 and TH16 (Mat1.2) provided by CIRAD. 73 fertile isolates were tested with SCAR markers of 13 pairs of primers. Preliminary results showed that the geographic distribution of M.grisea existed among isolates collected from the same location as well as different locations and the genetic relationship between fertile isolates of the fungus in China. The existence of sexual reproduction of M .grisea was explored in the field as well.

Hospital-Based Phenotypic Features and Treatment Outcomes of Chinese Women with Polycystic Ovary Syndrome: The Effect of Body Mass Index and Geographic Distribution

Genetic,lifestyle,and environmental factors contribute to the etiology of polycystic ovary syndrome(PCOS).Increased body mass index(BMI)exacerbates the reproductive and metabolic parameters and reduces the fecundity of women with PCOS.This is a secondary analysis of a large-sample,multicenter,randomized controlled trial conducted at 21 sites in Chinese mainland.A total of 1000 women diagnosed with PCOS were enrolled in this trial.Of these,998 women with PCOS were included in the analysis.Increased BMI was associated with more severe menstrual irregularities,elevated testosterone level,higher prevalence of metabolic syndrome,and poorer quality of life.The rates of ovulation per woman for the normal,overweight,and obese BMI groups were 83.0%,78.2%,and 63.6%,respectively(P<0.001),and the rates of live birth were 23.6%,18.1%,and 15.3%(P=0.030).Northern PCOS patients showed more severe reproductive,glucose,and lipid profiles;less exercise;and lower total ovulation rates compared with PCOS patients from Southern China(74.8%vs 81.2%,absolute difference 6.4%,95%confidence interval 1.2%–11.5%).The results show the typical phenotypic features of Han women with PCOS in Northern and Southern China.The women living in Northern China showed a higher BMI,more severe glycolipid metabolism profiles,and subsequently worse clinical outcomes by the same interventions than those living in Southern China.The difference in phenotypic features can be explained mostly by differences in BMI and the resulting difference in ovulation.

Change in current and future geographic distributions of Ulmus lamellosa in China

Prediction of potential geographic distributions is important for species protection and habitat restoration. Ulmus lamellosa is an endangered and endemic species in China for which conservation efforts are required. The maximum entropy （MaxEnt） model was used to predict the current and future geographic distribution （from 2030 to 2070） of U. lamellosa in China and discuss the reasons for changes in climatic suitability. The MaxEnt model provided a good fit to our data as confirmed by an AUC value of 0.948. The suitable areas for U. lamellosa were primarily projected in the northern part of China from 2030 to 2070, especially in Liaoning province. The variables ＂temperature seasonality＂, ＂precipitation of wettest month＂ and ＂precipitation of warmest quarter＂ were the most influential climatic variables in limiting the distribution of U. lamellosa. Our results clearly predict the future impacts of climate change on the geographic distribution of U. lamellosa and this can help prioritize design of localized conservation strategies in China.

IMMIGRATION, GEOGRAPHIC DISTRIBUTION AND SOCIAL ECONOMIC STATUS OF AMERICAN CHINESE

In 1994, the total Chinese population in the United States were 2,017,799 which were 0.8 percent of the total US population. The Chinese population were highly concentrated by regions and among the total population. By states, 42 percent of total Chinese population were found in California, 17 percent in New York. More than 80 percent total Chinese population were concentrated in 9 states. By metropolitan areas, 14.73 percent of total Chinese population were found in Los Angeles and New York respectively. Compared with the total US population, 60 percent Chinese population were found in less than 20 percent total US population and 80 percent in 50 percent. By studying the Chinese population distribution and the reason behind it, we hope to find some interesting relationships among the characteristics of this distribution and the historical, cultural, social and economic factors influencing it.

Epidemiological characterization and geographic distribution of human immunodeficiency virus/acquired immunodeficiency syndrome infection in North African countries

BACKGROUND Human immunodeficiency virus(HIV)infection is a major global public health concern.North African countries carry a disproportionate burden of HIV representing one of the highest rates in Africa.AIM To characterize the epidemiological and spatial trends of HIV infection in this region.METHODS A systematic review was carried out on all the published data regarding HIV/acquired immunodeficiency syndrome in North African countries over ten years(2008-2017)following the PRISMA guidelines.We performed a comprehensive literature search using Medline PubMed,Embase,regional and international databases,and country-level reports with no language restriction.The quality,quantity,and geographic coverage of the data were assessed at both the national and regional levels.We used random-effects methods,spatial variables,and stratified results by demographic factors.Only original data on the prevalence of HIV infection were included and independently evaluated by professional epidemiologists.RESULTS A total of 721 records were identified but only 41 that met the criteria were included in the meta-analysis.There was considerable variability in the prevalence estimates of HIV within the countries of the region.The overall prevalence of HIV ranged from 0.9%[95%confidence interval(CI)0.8-1.27]to 3.8%(95%CI 1.17-6.53).The highest prevalence was associated with vulnerable groups and particularly drug abusers and sexually promiscuous individuals.The dense HIV clustering noted varied from one country to another.At least 13 HIV subtypes and recombinant forms were prevalent in the region.Subtype B was the most common variant,followed by CRF02_AG.CONCLUSION This comprehensive review indicates that HIV infection in North African countries is an increasing threat.Effective national and regional strategies are needed to improve monitoring and control of HIV transmission,with particular emphasis on geographic variability and HIV clustering.

Estimation of the potential geographical distribution of a new potato pest(Schrankia costaestrigalis) in China under climate change

Global food security is threatened by the impacts of the spread of crop pests and changes in the complex interactions between crops and pests under climate change.Schrankia costaestrigalis is a newly-reported potato pest in southern China.Early-warning monitoring of this insect pest could protect domestic agriculture as it has already caused regional yield reduction and/or quality decline in potato production.Our research aimed to confirm the potential geographical distributions(PGDs)of S.costaestrigalis in China under different climate scenarios using an optimal MaxEnt model,and to provide baseline data for preventing agricultural damage by S.costaestrigalis.Our findings indicated that the accuracy of the optimal MaxEnt model was better than the default-setting model,and the minimum temperature of the coldest month,precipitation of the driest month,precipitation of the coldest quarter,and the human influence index were the variables significantly affecting the PGDs of S.costaestrigalis.The highly-and moderately-suitable habitats of S.costaestrigalis were mainly located in eastern and southern China.The PGDs of S.costaestrigalis in China will decrease under climate change.The conversion of the highly-to moderately-suitable habitat will also be significant under climate change.The centroid of the suitable habitat area of S.costaestrigalis under the current climate showed a general tendency to move northeast and to the middle-high latitudes in the 2030s.The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S.costaestrigalis in the suitable areas.More attention should be paid to the early warning and monitoring of S.costaestrigalis in order to prevent its further spread in the main areas in China’s winter potato planting regions.

Natural variations and geographical distributions of seed carotenoids and chlorophylls in 1167 Chinese soybean accessions

Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.Genotype,planting year,accession type,seed cotyledon color,and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.The mean total carotenoid content was in the range of 8.15–14.72μg g–1 across the ecoregions.The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.Remarkably,lutein was the most abundant carotenoid in all the germplasms,ranging from 1.35–37.44μg g–1.Carotenoids and chlorophylls showed significant correlations with other quality traits,which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.Collectively,our results demonstrate that carotenoids are adequately accumulated in soybean seeds,however,they are strongly influenced by genetic factors,accession type,and germplasm origin.We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs,and thereby as the raw materials for food sectors,pharmaceuticals,and the cosmetic industry.

Monitoring the little fire ant,Wasmannia auropunctata(Roger 1863),in the early stage of its invasion in China:Predicting its geographical distribution pattern under climate change

Invasive alien ants(IAAs)are among the most aggressive,competitive,and widespread invasive alien species(IAS)worldwide.Wasmannia auropunctata,the greatest IAAs threat in the Pacific region and listed in“100 of the world’s worst IAS”,has established itself in many countries and on islands worldwide.Wild populations of W.auropunctata were recently reported in southeastern China,representing a tremendous potential threat to China’s agricultural,economic,environmental,public health,and social well-being.Estimating the potential geographical distribution(PGD)of W.auropunctata in China can illustrate areas that may potentially face invasion risk.Therefore,based on the global distribution records of W.auropunctata and bioclimatic variables,we predicted the geographical distribution pattern of W.auropunctata in China under the effects of climate change using an ensemble model(EM).Our findings showed that artificial neural network(ANN),flexible discriminant analysis(FDA),gradient boosting model(GBM),Random Forest(RF)were more accurate than categorical regression tree analysis(CTA),generalized linear model(GLM),maximum entropy model(MaxEnt)and surface distance envelope(SRE).The mean TSS values of ANN,FDA,GBM,and RF were 0.820,0.810,0.843,and 0.857,respectively,and the mean AUC values were 0.946,0.954,0.968,and 0.979,respectively.The mean TSS and AUC values of EM were 0.882 and 0.972,respectively,indicating that the prediction results with EM were more reliable than those with the single model.The PGD of W.auropunctata in China is mainly located in southern China under current and future climate change.Under climate change,the PGD of W.auropunctata in China will expand to higher-latitude areas.The annual temperature range(bio7)and mean temperature of the warmest quarter(bio10)were the most significant variables affecting the PGD of W.auropunctata in China.The PGD of W.auropunctata in China was mainly attributed to temperature variables,such as the annual temperature range(bio7)and the mean temperature of the warmest quarter(bio10).The populations of W.auropunctata in southern China have broad potential invasion areas.Developing strategies for the early warning,monitoring,prevention,and control of W.auropunctata in southern China requires more attention.

Geographical distribution of Batrachospermaceae genera in Asia and its environmental factors

Batrachospermaceae is an important group of freshwater red algae.Available data of the latitude,longitude,and environmental factors on Batrachospermaceae distribution in Asia were analyzed to understand the geographical distribution of Batrachospermaceae genera in Asia.Statistical analyses,including one-way ANOVA,correlation analysis,stepwise regression analysis,principal component analysis,and linear discriminant analysis were conducted to characterize variation in geographical distribution and growth environment.Results reveal high variation in geographical distribution and growth environment among different Batrachospermaceae genera in Asia.Specifically,correlations between latitude and all environmental factors exclusive of altitude are significant,and longitude is significantly correlated with all environmental factors except for average relative humidity.The geographical distribution and growth environment of different Batrachospermaceae genera significantly differed.Altitude,maximum temperature,average temperature,minimum temperature,average relative humidity,average wind speed,maximum wind speed,and atmospheric pressure all contributed to explaining differences in the geographical distribution of Batrachospermaceae genera.Combining the results of correlation analysis,stepwise regression analysis,and principal component analysis,all environmental factors contributed to the different geographical distribution of Batrachospermum,Paludicola,Sheathia,Sirodotia,and Remainder(the rest),all environmental factors but atmospheric pressure contributed to the different geographical distribution of Kumanoa,and all environmental factors but average wind speed and maximum wind speed contributed to the different geographical distribution of Virescentia.However,the correlation between these significantly related environmental factors and taxa is not necessarily causative,and many other environmental factors,such as temperature,pH,conductivity,shading,current velocity,dissolved oxygen,hardness,substrata types,and nutrients etc.,are likely to have an important impact on the geographical distribution of taxa,which is an important topic for future research.

Colletotrichum species and complexes:geographic distribution,host range and conservation status

The taxonomy of the genus Colletotrichum has undergone tremendous changes over the last decade,with over 200 species being currently recognised and species complexes being informally used to cluster those species.Many of these species are important plant pathogens,some rather polyphagous and others host-specific,but several occur seldomly and some may in fact be ecologically endangered.Based mainly on literature from the past decade,in this work we review the occurrence,geographic distribution and host spectrum of currently recognised Colletotrichum species under phylogenetic,pathologi-cal/agronomic and ecological perspectives,providing a list arranged by Colletotrichum species and species complexes.A total of 257 species are listed and grouped into 15 species complexes.In this work we have recorded 1353 unique host species-Colletotrichum species association records from 720 hosts,with the Fabaceae as the family with higher number of hosts(52 host species)but with the Rosaceae as the family with the highest number of host species-Colletotrichum species association records(118 association records).According to occurrence data,88 species are common in nature,128 were considered as data deficient and 41 are threatened,some of which are likely extinct from nature and preserved only in cul-ture collections.Several species are relevant plant pathogens,in some cases geographically confined and thus of potential quarantine relevance.Based on the major changes that occurred on Colletotrichum taxonomy over the last decade,this work provides a comprehensive overview of occurrence data of Colletotrichum species,compiling host range and geographical distribution,with relevance for plant pathology and conservation mycology.The current taxonomic framework in Colle-totrichum is revealing numerous species but poses challenges to the employment of standard criteria for the evaluation of biological conservation of these fungi.We advocate that conservation mycology and taxonomy should find common routes simultaneously enabling the correct delimitation of species of Colletotrichum and the implementation of feasible criteria for the evaluation of conservation.The employment of new technologies,such whole genome sequencing(WGS),will help and support the description of new species and to gain a better understanding of the genetic bases of speciation processes.

Geographic distribution and prevalence of human echinococcosis at the township level in the Tibet Autonomous Region

Background Echinococcosis,a zoonotic parasitic disease,is caused by larval stages of cestodes in the Echinococcus genus.Echinococcosis is highly prevalent in ten provinces/autonomous regions of western and northern China.In 2016,an epidemiological survey of Tibet Autonomous Region(TAR)revealed that the prevalence of human echinococcosis was 1.66%,which was much higher than the average prevalence in China(0.24%).Therefore,to improve on the current prevention and control measures,it is important to understand the prevalence and spatial distribution characteristics of human echinococcosis at the township level in TAR.Methods Data for echinococcosis cases in 2018 were obtained from the annual report system of echinococcosis of Tibet Center for Disease Control and Prevention.Diagnosis had been performed via B-ultrasonography.The epidemic status of echinococcosis in all townships in TAR was classified according to the relevant standards of population prevalence indices as defined in the national technical plan for echinococcosis control.Spatial scan statistics were performed to establish the geographical townships that were most at risk of echinococcosis.Results In 2018,a total of 16,009 echinococcosis cases,whose prevalence was 0.53%,were recorded in 74 endemic counties in TAR.Based on the order of the epidemic degree,all the 692 townships were classified from high to low degrees.Among them,127 townships had prevalence rates≥1%.The high prevalence of human echinococcosis in TAR,which is associated with a wide geographic distribution,is a medical concern.Approximately 94.65%of the villages and towns reported echinococcosis cases.According to spatial distribution analysis,the prevalence of human echinococcosis was found to be clustered,with the specific clustering areas being identified.The cystic echinococcosis primary cluster covered 88 townships,while that of alveolar echinococcosis’s covered 38 townships.Conclusions This study shows spatial distributions of echinococcosis with different epidemic degrees in 692 townships of TAR and high-risk cluster areas at the township level.Our findings indicate that strengthening the echinococcosis prevention and control strategies in TAR should directed at townships with a high prevalence and high-risk clustering areas.

Geographical distribution of general aerobic heterotrophic bacteria in surficial sediments from the Chukchi Sea and Canadian Basin

This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The result shows that the determination percentages of the GAB were high, even till 100 percentage. The abundance range and averages of GAB for 4℃and 25℃ were from 4.00 × 10^2 to 2.40× 10^6 , 1.71×10^6 ind.·g^-1 （wet sample ） and from 2.40 ×10^5 to 2.40×10^7 , 1.10×10^7 ind. ·g^-1 （wet sample ） respectively. Not only the abundance range but also the averages of GAB in 25℃ were higher than that in 4℃. The abundance of GAB in sediments show a tendency that it is roughly greater in the lower latitudinal area than in the higher latitudinal area. The abundance of GAB increased from east to west as for the longitudinal distribution. With the water depth increasing, the abundance of GAB at 4℃ decreased, but GBA at 25℃ is not changed obviously with water depth. It seems that warmer circumstantial temperature is more suitable for some GAB.

Preliminary Study on Geographical Distribution and Evolutionary Relationships Between Cultivated and Wild Adzuki Bean (Vigna angular is var. angularis and var. nipponensis) by AFLP Analysis

A set of representative 146 adzuki (Vigna angular is var. angularis, and var. nipponensis) germplasm from 6 Asian countries traditionally for adzuki bean production, together with an out group standard rice bean (Vigna umbellata), were analyzed by AFLP methodology using 12 informative primer pairs. 313 unambiguous polymorphic bands were created. According to the dendrogram by cluster analysis based on AFLP banding, 143 of the accessions were distinct and revealed enough genetic diversity for identification and classification of accessions within Vigna angularis. A neighbor joining tree was generated using newly developed Innan's nucleotide diversity estimate from the AFLP data. From analysis, 7 distinct evolutionary groups, named as "Chinese cultivated", "Japanese cultivated", "Japanese complex-Korean cultivated", "Chinese wild", "China Taiwan wild", "Nepal-Bhutan cultivated" and "Hymalayan wild", were detected. Nucleotide diversity with geographical distribution of each group is discussed, regarding the evolutionary relationships between wild and cultivated adzuki beans. The preliminary results indicated that cultivated adzuki bean should be domesticated from at least 4 progenitors in at least 3 geographical origins.

C_4 plant species and geographical distribution in relation to climate in the desert vegetation of China

Water use efficiency of Ca plants is higher than that of C3 plants, and CAM （Crassulaceae Acid Metabolism） plants have the highest water use efficiency. In the desert regions of China, CAM plants are scarce, and C4 plants, especiaUy C4 woody plants, have an important position and role in the desert ecosystem. There are 45 species of Ca woody plants in the desert regions of China, including semi-woody plants, accounting for 6% of the total desert plant species in China, and most of them are concentrated in the families of Chenopodiaceae and Polygonaceae, which are 19 species and 26 species, respectively. The number of C4 herbaceous plants is 107 species, including 48 monocot species and 59 dicot species. C4 woody plants mainly inhabit the northwestem arid desert regions of China west of the Helan Mountains. The drought-resistance and drought-tolerance of Ca herbaceous plants are worse than C4 woody plants, and C4 herbaceous plants mainly inhabit areas with shallow groundwater depth and better water conditions in the desert regions, and are widely distributed along the margins of oases. The abundance of C4 woody plants is closely correlated with drought, but the abundance of C4 herbaceous plants increases with wet conditions.

Geographical distribution of Aralia elata characteristics correlated with topography and forest structure in Heilongjiang and Jilin Provinces,Northeast China

The Araliaceae family consists of numerous species of medical plants of significant value as non-wood forest products.To conserve and culture these plants in natural forest stands is an important undertaking which should be implemented according to the relationship between forest structure and understory population.In this study,thirtyfive plots were established in natural A ralia elata stands.Taller individual and denser populations were found in the northern and in the eastern regions,respectively.Both population densities and individual leaf weight increased along longitude.In contrast,their relationship with elevation and DBH were negative.Along with the altitude gradient,both height and root-collar diameter increased but population density declined.Root-collar diameter and population density decreased with latitude and DBH,respectively.Overall,dominant trees unlikely enforced strong disturbance to the development of understory A.elata populations unless concerning some specific topographic factors.

Prediction of the global potential geographical distribution of Hylurgus ligniperda using a maximum entropy model

Background: Hylurgus ligniperda(Fabricius) is native to Europe but has established populations in many countries and regions. H. ligniperda mainly infests Pinus species, and can cause severe weakness and even death of the host through its boring activity;it can also be a vector of various pathogenic fungi. This study was conducted to investigate the environmental variables limiting the distribution of H. ligniperda and the change trend of its suitable areas under climate change.Results: We used a maximum entropy model to predict the potential geographical distribution of H. ligniperda on a global scale under near current and future climatic scenarios using its occurrence data and environmental variables. The result shows that the areas surrounding the Mediterranean region, the eastern coastal areas of Asia, and the southeastern part of Oceania are highly suitable for H. ligniperda. The environmental variables with the greatest effect on the distribution of H. ligniperda were determined using the jackknife method and Pearson’s correlation analysis and included the monthly average maximum temperature in April, precipitation of driest quarter, the monthly average minimum temperature in December, precipitation of coldest quarter, mean temperature of driest quarter and mean diurnal range.Conclusions: Excessive precipitation in winter and low temperatures in spring had a great effect on the distribution of H. ligniperda. The potential geographical distribution of H. ligniperda was predicted to change under future climatic conditions compared with near current climate conditions. Highly suitable areas, moderately suitable areas and low suitable areas were predicted to increase by 59.99%, 44.43% and 22.92%, respectively, under the2081–2100 ssp245 scenario.

The change of geographical distribution of two Asian species of rhinoceros in Holocene

At present only five species of rhinoceros surrive in the world, among which three in Asia No wild rhinoceros has been found alive in East Asia now But many recent evidences reveal the fact that rhinoceros still lived not very long ago in the East Asian Continent of Holocene The attention to East Asia rhinoceros in Holocene first arose from archaeological studies on ancient ruins in China Archaeologists first found some subfossil skeletons of rhinoceros in ruins of Yin Dynasty in Anyang of Henan in the 1930s Then more skeletons of rhinoceros were found in many other Neolithic Ages runis, such as in Tonghai (Yunnan), Nanning (Guangxi), Xichuan (Henan), Yuyao (Zhejiang), and Haian (Jiangsu).(Guangxi Archaeological Team 1972; Jia 1977; Wu 1983; Huang and Liang 1984; Xu 1990). Moreover, Zhou Benxiong reported some rhinoceros teeth containing residual organic matter found in caves in the middle and lower reaches of Yangtze River According to a number of very now skeletons of rhinoceros found in some caves in Central China and South China, Yang Zhongjian drew the inferences that rhinoceros might live in the Southern part of China until in the Han Dynasty (about 2000 yrs B P ) at least These discoveries provided the material evidences for the distribution of rhinoceros in East Asian Continent Recently, some scholars brought forward more new information about Chinese rhinoceros from the analysis of historical records and investigations of unearthed cultural relics respectively (Wen and He 1981; Sun 1982). Based on the above materials and informations, this paper is going to deal with the species of rhinoceros once living in East Asia from the viewpoint of zoo geography At last, we brouhgt up the evolution process of the rhinoceros in distribution in Asia with comprehensive analysis of physiographical elements and human activities

Characteristics of phosphorus chemistry and its geographical distribution in

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｐｈｏｓｐｈｏｒｕｓｃｈｅｍｉｓｔｒｙａｎｄｉｔｓｇｅｏｇｒａｐｈｉｃａｌｄｉｓｔｒｉｂｕｔｉｏｎｉｎｔｈｅＨａｉｈｅＲｉｖｅｒｖａｌｌｅｙ，ＮｏｒｔｈＣｈｉｎａＪｉａｎｇＧａｏｍｉｎｇ；ＨｕａｎｇＹｉｎｘｉａｏ；Ｌ...

Mesozooplankton distribution and diversity from the Bering Sea shelf to the Chukchi Sea

In recent decades,environmental changes in the Arctic have aroused widespread concern around the world.To better understand ecology issues such as ecosystem dynamics,the Arctic and the subarctic regions were integrated as the“pan-Arctic”region.In this study,mesozooplankton were sampled from the Bering Sea shelf to the northern Chukchi Sea during the 10th Chinese National Arctic Research Expedition in 2019.Based on the species composition and abundance,three geographical communities were identified:the Bering Sea shelf community(BSS),the Bering Strait transitional community(BST),and the Chukchi Sea shelf community(CSS).The BSS was characterized by Bering Sea oceanic species such as Eucalanus bungii;the BST was mainly composed of the pan-Arctic distributed Calanus glacialis,meroplankton of benthos,and neritic species such as Centropages abdominalis;copepods,especially the copepodite of C.glacialis,were predominant in the CSS community.The BSS community structure was strongly affected by the inflow of Bering Shelf Water,while those of BST and CSS were determined by the recruitment of local species.The zooplankton community structure is influenced by both advection and environmental changes such as warming and a prolonged productivity period.Here,it was difficult to distinguish the changes induced by climate change from the effects of the Bering Sea Water.The key to solving this problem is the accumulation of comparable data,which requires continuous monitoring of key species such as C.glacialis and Calanus hyperboreus.