Southeast Coast Of China Research Articles

Systematics of the mudskipper genusOxudercesEydoux & Souleyet 1848 (Teleostei: Gobiidae: Oxudercinae) with resurrection from synonymy ofO. nexipinnis(Cantor 1849)

The mudskipper (Gobiidae: Oxudercinae) genus Oxuderces Eydoux & Souleyet is re-diagnosed with five putative synapomorphies: (1) a fleshy, dorsal, interorbital trough or slit supported internally by expanded, curved medial margins of the frontal bones and lined with a thick epidermis and thin dermis (vs. no fleshy, interorbital trough, medial margins of the frontal bones expanded but not curved, and epidermis extremely thin and dermis thick); (2) highly thickened epidermis over the eye (vs. thickened dermis); (3) neural spine of the fourth vertebra broad and spatulate (vs. narrow and pointed); (4) anterior ceratohyal posterior to fourth branchiostegal ray insertion elongate and notched (vs. not elongate, or elongate and not notched); and (5) angle between the metapterygoid–symplectic–quadrate strut and the anguloarticular acute (vs. angle obtuse). The fleshy, dorsal, interorbital trough is a unique character for Oxuderces that is not observed in other oxudercine gobies or gobioid fishes. The extremely thick epidermis may help the skin remain moist when exposed to the air and facilitate cutaneous respiration. Two allopatric species are included in the genus Oxuderces: Oxuderces dentatus Eydoux & Souleyet, 1848, from the south-east coast of China, is the type species; Oxuderces nexipinnis (Cantor, 1849), from the Indo-West Pacific, is resurrected from synonymy of O. dentatus sensu Murdy (1989). Apocryptodon wirzi Koumans, 1937, a species classified in Oxuderces by Murdy (1989) is reassigned to Apocryptodon based on a posteriorly directed laminar process on the parapophyses of the fourth vertebra. Oxuderces nexipinnis uniquely has a dermal invagination of unknown function just posterior to the point of attachment of the pelvic-fin base.

'Muslim Diaspora' in Yuan China: A Comparative Analysis of Islamic Tombstones from the Southeast Coast

This paper presents a case study of the Muslim diaspora through comparative analysis of Islamic tombstones from the Southeast Coast of China under Mongol rule. The locations of the nisbas in the Islamic tombstones are widely dispersed, covering Xinjiang, Transoxiana, Iran, Khorasan, Khwarazm, Armenia, Syria, Palestine, and Arabia. Unexpectedly, we did not find a single named location from India or Southeast Asia. It is well known that notable descendants of distinguished families traditionally produced officials, intellectuals, and wealthy merchants, and surrendered to the Mongols during the war against the Qara Khitai Khanate and the Khwarazm Empire. There were a great number of appointed officials with Muslim names in the Jianghuai (around Lower Yangtze) and Fujian regions. This is consistent with the concentration of epitaphs written in Arabic on the southeast coast of China. The frequent use of the specific tradition of the prophet Muhammad associating the death of the exile with martyrdom in Islamic tombstones in Quanzhou, Hangzhou, and Yangzhou indicates that the Muslims in these port cities eventually established an interregional or diasporic identity of Muslim foreighners whoimmigrated into the region.

Enteropathogens in children less than 5years of age with acute diarrhea: a 5-year surveillance study in the Southeast Coast of China.

BackgroundDiarrhea is the second most common cause of death among children less than 5 years of age worldwide. The etiological agents of diarrhea in the southeast coastal area of China were studied from July 2009 to December 2014.MethodsA total of the 2318 patients were enrolled in this study and examined for the presence of viruses, bacteria, and parasites. Multiplex real-time PCR was used for the detection of diarrheagenic Escherichia.coli (DEC). DEC strains were tested for susceptibility to a panel of 20 antibiotics using the Kirby-Bauer disc-diffusion method.ResultsOf the 2318 children with diarrhea, 962 (41.5 %) were positive for at least one pathogen. Rotavirus, human calicivirus (HucV), and DEC were predominant, with detection rates of 19.1 % (443), 17.7 % (411), and 7.6 % (177), respectively. The prevalences of various pathogens in patients of different ages and in different seasons were not the same. The resistance rates of 177 strains of DEC to ampicillin, tetracycline, and cefazolin were 93.2 %, 60.0 %, and 57.7 %, respectively.ConclusionsRotavirus, HucV, and DEC were the main pathogens associated with diarrhea in Zhejiang, China. DEC possessed high levels of antibiotic resistance. Increased monitoring of etiological agents of diarrhea is necessary.

Research on Formation Mechanisms of Hot Dry Rock Resources in China

AbstractAs an important geothermal resource, hot dry rock (HDR) reserves have been studied in many countries. HDR resources in China have huge capacity and have become one of the most important resources for the potential replacement of fossil fuels. However, HDR resources are difficult to develop and utilise. Technologies for use with HDR, such as high‐temperature drilling, reservoir characterisation, reservoir fracturing, microseismic monitoring and high‐temperature power stations, originate from the field of oil and drilling. Addressing how to take advantage of these developed technologies is a key factor in the development of HDR reserves. Based on the thermal crustal structure in China, HDR resources can be divided into four types: high radioactive heat production, sedimentary basin, modern volcano and the inner‐plate active tectonic belt. The prospective regions of HDR resources are located in South Tibet, West Yunnan, the southeast coast of China, Bohai Rim, Songliao Basin and Guanzhong Basin. The related essential technologies are relatively mature, and the prospect of HDR power generation is promising. Therefore, analysing the formation mechanisms of HDR resources and promoting the transformation of technological achievements, large‐scale development and the utilisation of HDR resources can be achieved in China.

Pollution characteristics of atmospheric particulate mercury near a coal-fired power plant on the southeast coast of China

PM2.5 and PM10 samples were collected in a rural area from December 2014 to August 2015 near a coal-fired power plant on the southeast coast of China. The total mercury concentrations in PM2.5 ranged from 116.2 to 1070.9 pg/m3 and in PM10 from 173.4 to 1456.8 pg/m3, with averages of 309.5 ± 94.9 and 387.5 ± 133.5 pg/m3, respectively. These were much higher than those found in many foreign cities. The concentrations of mercury in PM2.5 and PM10 varied seasonally, with the highest average concentration in winter. This was probably due to the seasonal variation of meteorological conditions and concentration of particulates. The highest mass-based concentration of mercury in PM2.5 and PM10 was observed in spring. This result might be related to the prevailing sea winds in spring. The spatial variation of particulate mercury conformed to the concentration distribution characteristics of pollutant discharged from coal-fired power plant elevated source at the downwind area. The seasonal variation in the concentrations of the four mercury species (including exchangeable particulate mercury: EXPM, HCl-soluble particulate mercury: HPM, elemental particulate mercury: EPM, and residual particulate mercury: RPM) were all identical to the seasonal variation of total particulate mercury (TPM) in PM2.5 and PM10 (winter > spring > summer). Owing to the variation of meteorological conditions, the proportion of different mercury species in TPM followed different seasonal trends. In contrast to RPM, the percentage of both HPM and EPM in PM2.5 was higher than in PM10.

Concentrations, distribution and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in coastal sediments from Xiamen, China

Xiamen and its surroundings are representative areas suffering from intense anthropogenic turbulence and contamination in southeast coast of China during rapid industrialization and urbanization period, thus relevant organic pollutants research is necessary to assess the coastal environmental quality and generate management strategy. Contamination status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) was investigated for 7 surface sediment samples collected in these areas in January 2007. The given data were used to evaluate the contamination and their potential risks of the pollutants. Concentrations of PCDD/Fs were in the range of 60 to 4089pgg−1 (dry weight) with an average of 1706pgg−1 and DL-PCBs in the range of 3 to 76pgg−1 with an average of 28pgg−1. Octa-chlorinated dibenzo-p-dioxin (OCDD) and PCBs 105 and 118 were the main congeners of the PCDD/F and DL-PCB, respectively. The toxicity equivalent concentrations (TEQs) were in the range of 0.15 to 5.2pgg−1 (average: 3.0pgg−1) for PCDD/Fs, while in the range of <limit of quantitation (LOQ) to 0.09pgg−1 (average: 0.05pgg−1) for DL-PCBs. Congener pattern analysis showed a dominance of OCDD, suggesting main sources were current or historical use of chlorophenol, current use of dioxin contaminated pesticides or atmospheric deposition. Due to the current levels of PCDD/Fs and DL-PCBs in this area, it is necessary to further research their biogeochemical processes and ecological influences in the future.

Heavy metal pollution and Pb isotopic tracing in the intertidal surface sediments of Quanzhou Bay, southeast coast of China

Concentrations of 16 heavy metals and Pb isotopic ratios in the intertidal surface sediments of Quanzhou Bay were determined to study the pollution level of heavy metals and the sources of Pb. The results showed that most concentrations of Cd, Sn, Mn, Cu, Zn, Cr, Pb, Hg, Ni, Co, Cs, Fe and V were higher than the background values, while most concentrations of Ti, Sb and Sr were lower than the background values. The mean concentrations of Cu, Zn, Pb, Cr and Cd exceeded the first-grade criteria of Chinese marine sediment quality. The geo-accumulation indexes revealed that the sediments had been polluted by some heavy metals. The results of Pb isotopic tracing indicated that the total Pb in the sediments were mainly from parent material, industrial emission and vehicle exhaust with the mean contributions of 38.2%, 51.3% and 10.5%, respectively, calculated by a three-end-member model of Pb isotopic ratios.

Environmental and Ecological Risk Assessment of Trace Metal Contamination in Mangrove Ecosystems: A Case from Zhangjiangkou Mangrove National Nature Reserve, China.

Zhangjiangkou Mangrove National Nature Reserve is a subtropical wetland ecosystem in southeast coast of China, which is of dense population and rapid development. The concentrations, sources, and pollution assessment of trace metals (Cu, Cd, Pb, Cr, Zn, As, and Hg) in surface sediment from 29 sites and the biota specimen were investigated for better ecological risk assessment and environmental management. The ranges of trace metals in mg/kg sediment were as follows: Cu (10.79–26.66), Cd (0.03–0.19), Pb (36.71–59.86), Cr (9.67–134.51), Zn (119.69–157.84), As (15.65–31.60), and Hg (0.00–0.08). The sequences of the bioaccumulation of studied metals are Zn > Cu > As > Cr > Pb > Cd > Hg with few exceptions. Cluster analysis and principal component analysis revealed that the trace metals in the studied area mainly derived from anthropogenic activities, such as industrial effluents, agricultural waste, and domestic sewage. Pollution load index and geoaccumulation index were calculated for trace metals in surface sediments, which indicated unpolluted status in general except Pb, Cr, and As.

Genetic diversity and population structure of Fenneropenaeus penicillatus determined by mitochondrial DNA analyses.

Fenneropenaeus penicillatus is a widely distributed economically and ecologically important shrimp species, which is endangered in China. Sequence analysis of 16s rRNA and control region (CR) fragments from mitochondrial DNA was conducted to obtain information on genetic diversity and population structure. Individuals from 12 wild F. penicillatus populations located along the southeast coast of China were used. Polymerase chain reaction (PCR) fragments of the CR gene revealed high genetic diversity among the 12 populations; however, PCR fragments of the 16s rRNA gene revealed very low genetic diversity in the Hainan (HN) and Ningde (ND) populations and high genetic diversity in the DS, BH, PT, XM, and SZ populations. Data obtained from the CR and 16s rRNA genes suggested that high genetic differentiation exists among the 12 populations, which is mainly due to the high genetic differentiation between HN and all other 11 populations. These results may be useful for further sustainable management and utilization of this species.

Doppler Radar Analysis of Triple Eyewalls in Typhoon Usagi (2013)

Abstract Strong tropical cyclones often undergo eyewall replacement cycles that are accompanied by concentric eyewalls and/or rapid intensity changes while the secondary eyewall contracts radially inward and eventually replaces the inner eyewall. To the best of our knowledge, the only documented partial/incomplete tertiary eyewall has been mostly inferred from two-dimensional satellite images or one-dimensional aircraft flight-level measurements that can be regarded as indirect and tangential. This study presents the first high spatial and temporal resolution Doppler radar observations of a tertiary eyewall formation event in Typhoon Usagi (2013) over a 14-h time period before it makes landfall. The primary (tangential) and secondary (radial) circulations of Usagi deduced from the Ground-Based Velocity Track Display (GBVTD) methodology clearly portrayed three distinct axisymmetric maxima of radar reflectivity, tangential wind, vertical velocity, and vertical vorticity. Usagi’s central pressure steadily deepened during the contraction of the secondary and tertiary eyewalls until the tertiary eyewall hit the coast of southeast China, which erminated the intensification of the storm.

Effectiveness of national nature reserve network in representing natural vegetation in mainland China

The conservation of natural vegetation directly impacts biodiversity conservation; thus, it is important to evaluate the effectiveness of vegetation protection in nature reserve networks. In this study, ArcGIS 10.0 was used for gap analysis of terrestrial vegetation protection within the national nature reserve network in mainland China. Overall, 9.75 % of the land area was covered by 366 national nature reserves. The bias of the protection ratio was particularly obvious among the different vegetation regions, zones, provinces and districts. The warm temperate deciduous broadleaf forest region was the least protected (1.84 %), and most of the NNRs were located in the Qinghai-Xizang Plateau alpine vegetation region (35.8 %). Moreover, in most vegetation zones (57.14 %), less than 5 % of the area was protected, and in vegetation provinces and vegetation districts, 8.85 and 35.87 %, respectively, were not protected by national nature reserves. However, the number of national nature reserves could be higher in these vegetation zones, provinces and districts than in other areas. The protection bias became more significant as the analysis scale decreased. In addition, nearly 25 % of the natural formations in mainland China were unprotected by national nature reserves. A bias was also observed in the protection of different natural formations, with a lack or lower degree of protection for desert, grass-forb community, steppe, and scrub biomes, which were spread throughout northwest and eastern China. A distinct lack of protected areas was observed in certain parts of the country. Therefore, additional land may require protection in the vegetation provinces and districts in the Tianshan Mountains, Junggar Basin, West Kunlun Mountains, Loess Plateau, and karst districts in southwest Guangxi Province and along the southeast coast of China.

Archaeal community structure and response to ark shell bioturbation in typical intertidal mudflats, Southeast coast of China

Although many studies have investigated archaeal distribution in various environments, studies regarding the archaeal community structure in intertidal mudflat sediments in coastal areas are not enough. In addition, the response of archaea to bivalves bioturbation has not been reported before, nevertheless, bioturbation effects on microbes are key to many aspects of ecosystem function. In this paper, clone library construction, Restriction Fragment Length Polymorphism (RFLP) and Denaturing Gradient Gel Electrophoresis DGGE (DGGE) were used to study the archaeal community structure in two typical intertidal mudflats in Southeast coast of China: the one mainly used for aquaculture in a semi-enclosed Bay (Sansha Bay), and the other one mainly used for recreation in a developed city (Xiamen). In addition, the potential influence of sampling time and the in situ bioremediation by artificially introducing bivalve ark shell (Tegillarca granosa) to mudflat sediments on archaeal communities were also investigated. A total of 283 clones were randomly selected from four clone libraries and were divided into 42 RFLP patterns. All the cloned sequences fell into three phyla: the Thaumarchaeota (group MGI), Crenarchaeota (group MCG) and Euryarchaeota (groups MBG-D, MBG-E, VAL III and DHVE 6), in which Thaumarchaeota MGI was dominant, occupying 75.6% of total clones. Crenarchaeota MCG and Euryarchaeota accounted for 15.2% and 9.2% respectively. The archaeal diversity in Xiamen intertidal sediment was lower than that of Sansha Bay. Introducing ark shell seemed to increase archaeal diversity and the proportion of MCG and decrease the proportion of MGI in the clone library. DGGE profiles showed that most of the archaea populations were metabolically active, and the fingerprint clustering results were basically consistent with the results from clone libraries.

Analysis of the northern South China Sea counter-wind current in winter using a data assimilation model

The South China Sea Warm Current (SCSWC) has drawn considerable attentions in the past decade due to its characteristic of flowing against the wind direction along the coast of Southeast China during winter. Observational monitoring of the SCSWC is yet insufficient to firmly assess of the property of this current. Prior modeling attempts have been carried out in idealized or simplified framework, e.g., coarse resolution, unrealistic wind forcing, artificial bathymetry, and/or missing dynamical processes. It is still unclear to what extent the above approximations may affect the properties of the SCSWC. In this study, a state-of-the-art data assimilation system of the South China Sea has been integrated from 1993 to 2005. The system uses the Hybrid Ocean Model (HYCOM) with tidal forcing and is forced with realistic atmospheric forcing. In order to ensure a more realistic positioning of the mesoscale features, the system assimilates along-track altimetry data with the Ensemble Optimal Interpolation (EnOI) to investigate the properties of the SCSWC for the period 1996–2005. The properties of the SCSWC in winter time are investigated and found: the current mainly follows the 100 m isobaths and exists from immediately below the surface to the depth of 50 m with a baroclinic structure; the main core is located at 20–30 m depths and is composed of water warmer than the shelf water; and the width of the current is less than 100 km. Meanwhile, based on the daily output, it was shown that the current is highly transient in January. Additional simulations without tidal forcing and without assimilation suggest that the transient property of the current is mainly driven by the atmospheric forcing while the mesoscale eddies enhance its variability. On the contrary, tidal forcing seems to reduce the strength of the SCSWC, as expected from tidal rectifying of the current.

Anthropogenic mercury sequestration in different soil types on the southeast coast of China

Soil is a major pool of anthropogenically emitted mercury (Hg) and will in turn be a source of atmospheric Hg contamination. It was hypothesized that accumulation of anthropogenic Hg in the soil at a regional scale is associated with the amount of Hg emitted to the atmosphere and soil type. A total of 448 horizon samples were collected from the typical soil types of the Yangtze River Delta and Pearl River Delta. Titanium (Ti) was selected as a reference element to discriminate anthropogenic Hg from the Hg associated with pedogenic processes. Soil pools of anthropogenic Hg were quantified to show the difference in Hg sequestration among soil types and regions. Soil pools of anthropogenic Hg ranged from 0.70 to 6971 g/ha in the Yangtze River Delta (YRD) and from 35.81 to 13098.71 g/ha in the Pearl River Delta (PRD). The estimated soil Hg pools were well correlated with the amounts of Hg emitted in these two regions. Soil properties, namely organic matter content, amorphous iron oxides, and cation exchange capacity, were significantly (p < 0.01) and positively correlated with soil Hg accumulation. Meanwhile, soil organic matter was the most important factor to determine the depth distribution of Hg in soil profile of the majority of soils. Perudic Cambisols and Stagnic Anthrosols which contained higher content of amorphous iron oxides had the highest soil Hg pools, indicating the importance of amorphous iron oxides other than organic matter to the Hg retention in soil. Soil and soil horizons with low pH and high salinity did show a low accumulation of Hg probably due to the remobilization of Hg under such conditions. In addition to the amount of Hg emitted, soil types may be a major factor in controlling the sequestration of anthropogenic Hg in both regions. Stagnic Anthrosols are an important pool for retention of anthropogenic Hg.

The discovery of Liangdao man and its implications for the pre-Austronesian homeland

The discovery of Liangdao man ca. 8,000 BP is academically significant. It may provide some clue for the Austronesian origin relating Taiwan and the southeast coast of China. We need interdisciplinary knowledge of archaeology, genetics and linguistics to make any meaningful study of such a case. The most recent genetic study indicates that the Liangdao man seems to be more closely related to modern Formosan natives than to the other peoples in South China and Southeast Asia. Ancient South China was almost exclusively populated by non-Chinese. There is linguistic evidence that the Austroasiatics inhabited the Yangtze delta and parts of the southeast coast during the first half of the first millennium B.C. Some of the Austroasiatic loanwords currently in Chinese in general and in Min are part of the basic vocabulary. This indicates the Chinese and Austroasiatics must have been in close contact for a long period of time before the first millennium B.C. The linguistic evidence for the genetic relationship between Austronesian and Austroasiatics is not very strong, but nevertheless exists. We can postulate that pre-Austronesian split apart from Austroasiatics in the southeast coast of China about 6,000 BP and dispersed to Taiwan to become proto-Austronesians.

利用近似贝氏计算推论台湾海峡沿岸秋茄种群的拓殖路线

PDF HTML阅读 XML下载 导出引用 引用提醒 利用近似贝氏计算推论台湾海峡沿岸秋茄种群的拓殖路线 DOI: 10.5846/stxb201402200297 作者: 作者单位: 北京林业大学,重庆三峡学院,北京林业大学,北京林业大学,重庆三峡学院,福建省漳江口红树林国家级自然保护区管理局 作者简介: 通讯作者: 中图分类号: 基金项目: 由ITTO(国际木材组织)与国家林业局共同资助《通过社区发展和能力建设实现中国红树林可持续经营(PD 460/07 Rev.2(F》 Kandelia obovata Colonization route along Taiwan Strait Inferenced by approximate Bayesian computation Author: Affiliation: The Academy of Forestry of Beijing Forestry University;Chongqing Three Gorges University;,The Academy of Forestry of Beijing Forestry University;,The Academy of Forestry of Beijing Forestry University;,,Fujian Zhangjiangkou Mangrove Nature Ｒeserve，Yunxiao 363300， Fujian，China; Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:由于地理关系,台湾海峡两岸的红树植物组成具有高度的相似性,都以耐寒性较强的秋茄为优势种。中国台湾(以下简称"台湾")与大陆仅一水之隔,因此台湾的秋茄种群来源最有可能来自东南沿海种群,然而台湾南、北红树植物种群的拓殖路线以及与大陆东南沿海种群的遗传关系的研究至今仍未见报道。通过SSR分子标记, 利用近似贝氏计算(Approximate Bayesian Computation)推测海峡两岸4个分布区域秋茄的起源及其拓殖路线。结果表明4个区域的种群出现明显分化,大陆东南北部种群与其他种群间分化程度最高。通过推测台湾北部种群起源可追溯到29000-48400a前,早于末次冰期时间,且台湾北部种群遗传结构与大陆东南南部种群最相近,推测它们可能共同起源于南方祖先。大陆东南沿海南北种群的溯祖时间约为15.1万年至25.2a年前,约为更新世中期末,则意味东南沿海南、北种群的遗传分化可能受到更新世后期气候变化与海侵海退的影响而出现隔离,或东南沿海南、北种群可能来自不同的起源。而台湾南部种群与台湾北部种群的相似性,表明台湾南部种群是由北部种群拓殖而来,近似贝氏计算亦支持这个假说。因而,可以推测海峡两岸秋茄的拓殖路线是从大陆东南南方种群随黑潮迁移至台湾北部,再从北部拓殖到台湾南部。利用近似贝氏计算推论台湾海峡两岸红树林种群起源及拓殖路线,为未来我国东南沿海红树林植物的生物地理研究提供参考。 Abstract:The community compositions of mangroves in both southeastern coasts of mainland China and west coast of Taiwan share great similarities because of topogeographic reasons and Kandelia obovata, with its higher cold-tolerance,is the dominant mangrove species on either side of the Strait. Therefore, K. obovata populations in Taiwan, China may most possibly derive from that of China southeast coastal areas. However, the colonization route of the northern and southern populations in Taiwan, China and their genetic relationship with that of mainland China have not been reported. In this study simple-sequence-repeat (SSR) markers and approximate-Bayesian-computation (ABC) were applied to trace its origins in the four distribution locations between the Strait. The results showed obvious differentiation among them and the northern part of the mainland southeastern coast illustrated a higher degree than the other three. It was also inferred that the origin of the northern Taiwan, China population could be trance back to circa 29000-48400 years ago, prior to the last glacial period and its genetic structure was the closest to the southern population of China southeast coast, suggesting they may derive from a common ancestor in the south. The northern and southern populations of the Southeast China coast probably coalesced circa 151000-252000 years ago, approximately during the late mid-Pleistocene. The possible implication lies in that the genetic differentiation between the northern and southern populations and their separation may caused by late-Pleistocene climate changes and sea transgression and regression or that they had different origins. Whereas the highest population similarity between the northern and southern Taiwan, China indicates that the southern population was colonized from the north one, and the hypothesis is also supported by the results of approximate Bayesian computation. It can be inferred therefore that the overall colonization route started from southern population of southeast China and migrated with the Kuroshio Branch Current to the north of Taiwan, China before it ultimately colonized in the south. The study is the first one to utilize approximate Bayesian computation to illustrate the origination and colonization route of mangrove populations between Taiwan, China Strait and has provided referential model for mangrove biogeographic research in coastal Southeast China. 参考文献 相似文献 引证文献

One-Dimensional Velocity Structure of the Crust in Fujian, Southeast China

12095 P-wave phase data were selected in this study from four NW-oriented and four NE-oriented explosion sounding survey lines conducted along the coast and midland of Southeast China during the years 2010 and 2012. The 1-D crust P-wave velocity model was obtained in the continental margin of Southeast China (Fujian Province) using the travel time residual as the threshold and performing linear iterative inversion. This crust model includes 5 layers with the velocities being 5.04, 5.44, 6.06, 6.16, 6.39 km s^(-1), respectively, with the bottom depths being 0.23, 2.82, 6.44, 18.81, 30.42 km, respectively, and the uppermost mantle velocity being 8.08 km s^(-1). Compared with previous work the four P-wave phase data could effectively reflect the shallow and deep crust characteristics. The joint inversion method involves both the velocity and depth. The results in this paper could therefore be more reasonable and applicable than previous findings, with fairly good control in both the shallow and deep crusts. These findings have practical significance for compiling the earthquake travel time table and precisely locating earthquakes in this area. This work also provides an accurate preliminary model for subsequent 2-D and 3-D velocity structure inversions in the Southeast China (Fujian Province) continental margin.

Holocene vegetation, environment and anthropogenic influence in the Fuzhou Basin, southeast China

A ∼40m sediment core (FZ4) was collected from the Fuzhou Basin, near the lower reaches of the Min River, in Fujian Province on the southeast coast of China. The sediment and pollen record contributes to our understanding of Holocene paleogeography, including local changes in vegetation and climate in the context of Neolithic cultural developments. The sediment record reveals a fluvial environment in the Fuzhou Basin during the late Pleistocene, and it demonstrates that a change from fluvial to estuarine conditions at ∼9000calyr BP resulted from postglacial sea level rise. Evidence of abundant marine diatoms and tidal flat laminations observed in the FZ4 sediments, implies that the Fuzhou Basin was under marine influence between ∼9000 and ∼2000calyr BP. After 2000calyr BP, a rapid retreat in coastline associated with fluvial aggradation and coastal progradation produced more shallow water for wetlands and initiated formation of the floodplain landscape. The pollen record reveals the presence of a dense subtropical forest between ca. 9000 and 7000calyr BP, representing the Holocene thermal maximum, which is linked with rising sea level and marine transgression in the Fuzhou Basin. Between ca. 5500 and 2000calyr BP, the thermophilous forest dominated by Castanopsis retreated and coniferous forest expanded, reflecting moderate climatic cooling during this period. Timing of the high frequencies for Pinus and ferns correspond with the mid-late Holocene cooling trend recorded in local mountain peatland and coastal regions of the lower Yangtze and Hanjiang deltas. Anthropogenically induced land cover change was negligible prior to the Tanshishan cultural period, which marks the beginning of Neolithic era sedentary village life on the Fujian coast around 5500 BP. The pollen transition at ca. 3000–1500calyr BP, distinguished by rising frequencies of Poaceae and taxa (including Cyperaceae and Artemisia) closely associated with agricultural land cover, indicates exploitation of newly formed lowlands in the emerging Min River floodplain. The historic era intensification of rice agriculture is reflected in this trend of rising frequencies of Poaceae. After ca. 2000calyr BP, we observe the onset of a marine regression followed by evidence for an intensely human-impacted environment characterized by sharp rises in pioneer plants such as Poaceae and Dicranopteris. This transition coincides with a rapid retreat of coastline and emergence of the Fuzhou Basin floodplain.

Phylogeography of Tetrancistrum nebulosi (Monogenea, Dactylogyridae) on the host of mottled spinefoot (Siganus fuscescens) in the South China Sea, inferred from mitochondrial COI and ND2 genes

To examine the phylogeographical pattern of Tetrancistrum nebulosi (Monogenea, Dactylogyridae) in the South China Sea, fragments of mitochondrial cytochrome c oxidase subunit I and NADH dehydrogenase subunit 2 genes were obtained for 220 individuals collected from 8 localities along the southeast coast of China and 1 locality in Terengganu, Malaysia. Based on these two genes, two and three distinct clades with geographic signals were revealed on the phylogenetic trees respectively. The divergence between these clades was estimated to occur in the late Pleistocene. Analysis of molecular variance and pairwise FST suggested a high rate of gene flow among individuals sampled from the Chinese coast, but with obvious genetic differentiation from the Malaysian population. Mismatch distribution and neutrality tests indicated that the T. nebulosi population experienced expansion in Pleistocene low sea level periods. Vicariance was considered to account for the genetic divergence between Chinese and Malaysian populations, while sea level fluctuations and mainland-island connections during glacial cycles were associated with the slight genetic divergence between the populations along the mainland coast of China and those off Sanya. On the contrary, oceanographic circulations and host migration could lead to genetic homogeneity of populations distributed along the mainland coast of China.

Transcriptome analysis of the differences in gene expression between testis and ovary in green mud crab (Scylla paramamosain).

BackgroundThe green mud crab (Scylla paramamosain) is the most prevalent crustacean on the southeast coast of China. The molecular regulatory mechanism of sex determination and gonadal differentiation in this species has received considerable attention in recent years because of the huge differences—both biological and economic—between male and female crabs. In this study, next-generation sequencing technology was used to develop deep-coverage transcriptomic sequencing data for the testis and ovary of S. paramamosain.ResultsA total of 365,116 reads (testis 171,962, ovary 193,154) with an average sequence length of 285 bp were produced from testis and ovary cDNA libraries. After filtering out contaminating reads, the clean reads were assembled, producing a total of 21,791 isotigs and leaving 22,814 reads as singlets. Using the BLASTX program, 3,471 unique sequences (2,275 isotigs and 1,196 singletons) were annotated with known protein sequences from the NCBI non-redundant (Nr) protein sequence database. The Gene Ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses allowed the 224 unique sequences that were annotated with enzyme code (EC) numbers to be mapped into 174 KEGG pathways. After comparing the ovary and testis libraries, 4,021 gonad-differentially, 10,522 ovary-specifically, and 19,013 testis-specifically expressed genes were identified. Moreover, 33 ovary-specific, 14 testis-specific, and 34 gonad-differential transcripts were confirmed by semi-quantitative PCR and quantitative real-time PCR. In addition, 8,610 putative simple sequence repeats (SSRs) and 23,879 potential single nucleotide polymorphisms (SNPs) were identified.ConclusionThis is the first large-scale RNA sequencing of S. paramamosain to be reported. We have identified many important functional genes and made a preliminary attempt to construct the regulatory network involved in the gonadal development of crustaceans. The annotated transcriptome data will provide fundamental support for future research into the reproduction biology of S. paramamosain. A large number of candidate SSRs and SNPs were detected, which could be used as genetic markers for population genetics and functional genomics in this species.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-585) contains supplementary material, which is available to authorized users.