Shallow ocean response to tropical cyclones observed on the continental shelf of the northwestern South China Sea

NASA Astrophysics Data System (ADS)

Yang, Bing; Hou, Yijun; Hu, Po; Liu, Ze; Liu, Yahao

2015-05-01

Based on observed temperature and velocity in 2005 in northwestern South China Sea, the shallow ocean responses to three tropical cyclones were examined. The oceanic response to Washi was similar to common observations with 2°C cooling of the ocean surface and slight warming of the thermocline resulted from vertical entrainment. Moreover, the wavefield was dominated by first mode near-inertial oscillations, which were red-shifted and trapped by negative background vorticity leading to an e-folding timescale of 12 days. The repeated reflections by the surface and bottom boundaries were thought to yield the successive emergence of higher modes. The oceanic responses to Vicente appeared to be insignificant with cooling of the ocean surface by only 0.5°C and near-inertial currents no larger than 0.10 m/s as a result of a deepened surface mixed layer. However, the oceanic responses to Typhoon Damrey were drastic with cooling of 4.5°C near the surface and successive barotropic-like near-inertial oscillations. During the forced stage, the upper ocean heat content decreased conspicuously by 11.65% and the stratification was thoroughly destroyed by vertical mixing. In the relaxation stage, the water particle had vertical displacement of 20-30 m generated by inertial pumping. The current response to Damrey was weaker than Washi due to the deepened mixed layer and the destroyed stratification. Our results suggested that the shallow water oceanic responses to tropical cyclones varied significantly with the intensity of tropical cyclones, and was affected by local stratification and background vorticity.

Synergistic contribution of precipitation anomalies over northwestern India and the South China Sea to high temperature over the Yangtze River Valley

NASA Astrophysics Data System (ADS)

Liu, Ge; Wu, Renguang; Sun, Shuqing; Wang, Huimei

2015-09-01

This study explores the characteristics of high temperature anomalies over eastern China and associated influencing factors using observations and model outputs. Results show that more long-duration (over 8 days) high temperature events occur over the middle and lower reaches of the Yangtze River Valley (YRV) than over the surrounding regions, and control most of the interannual variation of summer mean temperature in situ. The synergistic effect of summer precipitation over the South China Sea (SCS) region (18°-27°N, 115°-124°E) and the northwestern India and Arabian Sea (IAS) region (18°-27°N, 60°-80°E) contributes more significantly to the variation of summer YRV temperature, relative to the respective SCS or IAS precipitation anomaly. More precipitation (enhanced condensational heating) over the SCS region strengthens the western Pacific subtropical high (WPSH) and simultaneously weakens the westerly trough over the east coast of Asia, and accordingly results in associated high temperature anomalies over the YRV region through stimulating an East Asia-Pacific (EAP) pattern. More precipitation over the IAS region further adjusts the variations of the WPSH and westerly trough, and eventually reinforces high temperature anomalies over the YRV region. Furthermore, the condensational heating related to more IAS precipitation can adjust upper-tropospheric easterly anomalies over the YRV region by exciting a circumglobal teleconnection, inducing cold horizontal temperature advection and related anomalous descent, which is also conducive to the YRV high temperature anomalies. The reproduction of the above association in the model results indicates that the above results can be explained both statistically and dynamically.

Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhang, L.; Pan, Y.; Wang, Y.; Paulot, F.; Henze, D. K.

2015-09-01

Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind of the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7 % over the South China Sea, and become important (greater than 30 %) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92 % contribution) and the Korean peninsula (7 %), and by sectors from fertilizer use (24 %), power plants (22 %), and transportation (18

Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

NASA Astrophysics Data System (ADS)

Zhao, Yuanhong; Zhang, Lin; Pan, Yuepeng; Wang, Yuesi; Paulot, Fabien; Henze, Daven

2016-04-01

Rapid Asian industrialization has lead to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2°× 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the much higher NH3 emissions reflect its intensive agricultural activities. We improve the seasonality of Asian NH3 emissions; emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further points out that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants

A numerical study of the South China Sea Warm Current during winter monsoon relaxation

NASA Astrophysics Data System (ADS)

Zhang, Cong; Ding, Yang; Bao, Xianwen; Bi, Congcong; Li, Ruixiang; Zhang, Cunjie; Shen, Biao; Wan, Kai

2018-03-01

Using a Finite-Volume Community Ocean Model, we investigated the dynamic mechanism of the South China Sea Warm Current (SCSWC) in the northern South China Sea (NSCS) during winter monsoon relaxation. The model reproduces the mean surface circulation of the NSCS during winter, while model-simulated subtidal currents generally capture its current pattern. The model shows that the current over the continental shelf is generally southwestward, under a strong winter monsoon condition, but a northeastward counter-wind current usually develops between 50-and 100-m isobaths, when the monsoon relaxes. Model experiments, focusing on the wind relaxation process, show that sea level is elevated in the northwestern South China Sea (SCS), related to the persistent northeasterly monsoon. Following wind relaxation, a high sea level band builds up along the mid-shelf, and a northeastward current develops, having an obvious vertical barotropic structure. Momentum balance analysis indicates that an along-shelf pressure gradient provides the initial driving force for the SCSWC during the first few days following wind relaxation. The SCSWC subsequently reaches a steady quasi-geostrophic balance in the cross-shelf direction, mainly linked to sea level adjustment over the shelf. Lagrangian particle tracking experiments show that both the southwestward coastal current and slope current contribute to the northeastward movement of the SCSWC during winter monsoon relaxation.

Occurrence of four Anaplasma species with veterinary and public health significance in sheep, northwestern China.

PubMed

Yang, Jifei; Han, Rong; Niu, Qingli; Liu, Zhijie; Guan, Guiquan; Liu, Guangyuan; Luo, Jianxun; Yin, Hong

2018-01-01

The members of the genus Anaplasma are important tick-borne rickettsial bacteria of veterinary and public health significance. Domestic ruminants are important reservoir hosts for several Anaplasma species. In this study, the occurrence of Anaplasma spp. was investigated by PCR in domestic small ruminants from Gansu, northwestern China. The results showed a high prevalence of Anaplasma spp. (46.2%, 201/435) in sheep. The average infection rates were 5.7%, 24.4%, 28.0% and 18.2% for A. ovis, A. bovis, A. phagocytophilum and A. capra, respectively. Coinfection of different Anaplasma species occurred in 96 (22.1%) sheep. The infections of Anaplasma species in sheep were confirmed by sequencing of msp4, 16S rRNA and gltA genes. Sequence analysis revealed a novel A. capra genotype in sheep that was distinct from the isolates identified from patients in northeastern China. This study gives the first insight of presence of four distinct Anaplasma species with veterinary and medical significance in sheep in northwestern China. Copyright © 2017. Published by Elsevier GmbH.

A Modelling Study of the Coastal Current in the Northwestern South China Sea: Response to Strong and Weak Southwest Monsoon

NASA Astrophysics Data System (ADS)

Ding, Y.; Yu, J.; Bao, X.; Yao, Z.

2016-02-01

The characteristics and dynamical mechanism of summer-time coastal current over the northwestern South China Sea (NSCS) shelf have been investigated based on a high resolution unstructured-grid finite volume community ocean model (FVCOM). Model-data comparison demonstrates that model well resolves the coastal dynamics over the NSCS shelf. The coastal current on the NSCS shelf is intensively influenced by monsoon and freshwater discharge of the Pearl River. Strong southwesterly wind drive the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of Pearl River estuary (PRE) advects toward southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer. Momentum balance analysis suggests that the along shelf barotropic pressure gradient due to the Pearl River discharge and wind forcing provides the main driving force for the southwestward coastal current.

Education, Employment and Empowerment: The Case of a Young Woman in Northwestern China

ERIC Educational Resources Information Center

Maslak, Mary Ann

2011-01-01

As a marginalized region of the world, the rural Gansu Province of northwestern China provides an informative canvas on which to examine and understand the ways in which education contributes to the lives of local Muslim women and supports their goals for work. Specifically, this article highlights the role education plays in the life of one young…

Countering Chinas Economic Statecraft in the South China Sea

DTIC Science & Technology

2018-04-09

Economic Statecraft in the South China Sea 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Bradford D...created and employed a vision and strategy to control it. China continually demonstrates its economic might in the region and conducts economic ...power to counter China’s rising influence in the South China Sea. The policy and strategy should incorporate establishing strong economic ties in

Analogous Study of the Linguistic Knowledge between Monolingual and Bilingual Students in the Minority Region of Northwestern China

ERIC Educational Resources Information Center

He, Hao

2008-01-01

Minority students' English learning is a special and an indispensable component of English education system in China. This article studies students' linguistic knowledge that live in Northwestern China--Gan Nan Autonomy State of Gan Su Province with majority population of Tibetan, mixed with Chinese and some Muslim. An analogous analysis is…

The ribbon continent of northwestern South America

NASA Astrophysics Data System (ADS)

Altamira-Areyan, Armando

The tectonic structure of the Plate Boundary Zone (PBZ) between the Caribbean Plate (CARIB) and the South American Plate (SOAM) is interpreted using models that require CARIB motion from the Pacific into the Atlantic. Those models can be subdivided into: (1) those in which the island arc rocks that are now in the CARIB-SOAM PBZ have collided with the northern South America margin, either obliquely or directly during the Cretaceous or during the Cenozoic, and (2) those in which the island arc rocks now in the CARIB-SOAM PBZ collided with the west coast of South America during the Cretaceous and were transferred to the northern margin by transform motion during the Cenozoic. Magnetic anomalies were first rotated in the Central and South Atlantic, holding Africa fixed to establish how much NOAM had converged on SOAM during the Cenozoic. WSW convergence was discovered to have been accommodated in the northern boundary of the CARIB. There is no evidence of convergence in the form of Cenozoic island arc igneous rocks on the north coast of South America. Those results are consistent only with models of Class (2) that call for transform movement of material that had collided with the west coast of South America along the CARIB-SOAM PBZ on the northern margin of South America. 40Ar/39Ar ages of island arc rocks from northern Venezuela were found to be older than ca 70 Ma, which is consistent with a requirement of models of Class (2) that those rocks are from an island arc which collided with the west coast of South America during Cretaceous times. Testing that conclusion using data from Ecuador, Colombia, Venezuela, the Netherlands Antilles, Trinidad and Tobago has led to the construction of a new ribbon continent model of the northwestern Cordillera of South America. Because the part of the ribbon continent on the north coast of South America has been experiencing substantial deformation in the Maracaibo block during the past 10 m.y., structures in that body have had to be

Ship Observations and Numerical Simulation of the Marine Atmosphericboundary Layer over the Spring Oceanic Front in the Northwestern South China Sea

NASA Astrophysics Data System (ADS)

Wang, D.; Shi, R.; Chen, J.; Guo, X.; Zeng, L.; Li, J.; Xie, Q.; Wang, X.

2017-12-01

The response of the marine atmospheric boundary layer (MABL) structure to an oceanic front is analyzed using Global Positioning System (GPS) sounding data obtained during a survey in the northwestern South China Sea (NSCS) over a period of about one week in April 2013. The Weather Research and Forecasting (WRF) model is used to further examine the thermodynamical mechanisms of the MABL's response to the front. The WRF model successfully simulates the change in the MABL structure across the front, which agrees well with the observations. The spatially high-pass-filtered fields of sea surface temperature (SST) and 10-m neutral equivalent wind from the WRF model simulation show a tight, positive coupling between the SST and surface winds near the front. Meanwhile, the SST front works as a damping zone to reduce the enhancement of wind blowing from the warm to the cold side of the front in the lower boundary layer. Analysis of the momentum budget shows that the most active and significant term affecting horizontal momentum over the frontal zone is the adjustment of the pressure gradient. It is found that the front in the NSCS is wide enough for slowly moving air parcels to be affected by the change in underlying SST. The different thermal structure upwind and downwind of the front causes a baroclinic adjustment of the perturbation pressure from the surface to the mid-layer of the MABL, which dominates the change in the wind profile across the front.

China’s Energy Insecurity and the South China Sea Dispute

DTIC Science & Technology

2011-03-24

St ra te gy R es ea rc h Pr oj ec t CHINA’S ENERGY INSECURITY AND THE SOUTH CHINA SEA DISPUTE BY COLONEL JAMES A. BRANDENBURG United...Project 3. DATES COVERED (From - To) Nov 2010-Mar 2011 4. TITLE AND SUBTITLE China’s Energy Insecurity and the South China Sea Dispute...CHINA’S ENERGY INSECURITY AND THE SOUTH CHINA SEA DISPUTE by Colonel James A. Brandenburg United States Air Force

Detection of Toxoplasma gondii oocysts in soils in northwestern China using a new semi-nested PCR assay.

PubMed

Wang, Meng; Meng, Peng; Ye, Qiang; Pu, Yuan-Hua; Yang, Xiao-Yu; Luo, Jian-Xun; Zhang, Nian-Zhang; Zhang, De-Lin

2014-09-28

Toxoplasma gondii is a zoonotic pathogen that can infect a range of animals and humans. Ingestion of T. gondii oocysts in soil is a significant transmission route for humans and animals acquiring toxoplasmosis. In the present study, we developed a new semi-nested PCR method to determine T. gondii oocysts distribution in soils in northwestern China. The one tube semi-nested PCR assay was developed to detect the oocysts of T. gondii in soil, targeting the repetitive 529 bp fragment of T. gondii genomic DNA. Then a total of 268 soil samples, including 148 samples from Gansu Province and 120 samples from Qinghai Province, northwestern China, were examined by the semi-nested PCR method. One third of the positive samples were sequenced. The sensitivity of the semi-nested PCR assay was 10(2)  T. gondii oocysts in 5 g soil sample. Investigation of soil samples from northwestern China showed that 34 out of 268 soil samples (12.69%) were T. gondii positive. Sequences of the partial 529 bp fragments varied from 0-1.2% among the sequenced samples. The prevalence of T. gondii oocysts in soil from cities (24/163) was slightly higher than that in soils from pasturing areas (10/105) (P = 0.21). Among the different regions in cities, the prevalence of T. gondii oocysts in soils from parks was 14.15%, whereas that in soils from schools was 19.05%. The present study firstly reported the prevalence of T. gondii oocysts in soils in northwest China using a novel semi-nested PCR assay, which provided baseline data for the effective prevention and control of toxoplasmosis in this region.

Proto-South China Sea plate tectonics using subducted slab constraints from tomography

NASA Astrophysics Data System (ADS)

Wu, J.; Suppe, J.

2017-12-01

The geology of the South China Sea and surrounding margins is intimately tied to the subduction of its predecessor, the proto-South China Sea. However, published plate reconstructions have shown highly variable sizes and locations for the proto-South China Sea. Despite these differences, most studies agree that the proto-South China Sea was subducted southwards under north Borneo in the Cenozoic. Here we present new details on proto-South China Sea paleogeography using mapped and unfolded slabs from seismic tomography following Wu et al. (2016). We show that most of the proto-South China Sea lithosphere lies directly under the South China Sea and is represented by an extensive (>1000 km N-S) swath of detached, sub-horizontal slab at 450 to 700 km depth, here called the `northern Proto-South China Sea'. Furthermore, slab unfolding shows that prior to subduction at the Manila Trench, the eastern limit of the South China Sea, lay directly above the edge of the `northern Proto-South China Sea', both extending 400 to 500 km to the east of the present Manila trench. These observations show that the South China Sea opened directly above a northward-subducting `northern Proto-South China Sea', which runs counter to most proto-South China Sea plate models. We present a slab-constrained plate reconstruction that shows the proto-South China Sea was consumed by double-sided subduction to both the north and south, as follows: [1] The `northern proto-South China Sea' subducted in the Oligocene-Miocene under the Dangerous Grounds and southward expanding South China Sea by in-place 'self subduction' similar to the western Mediterranean basins. [2] Limited southward subduction of the proto-South China Sea under Borneo occurred pre-Oligocene, represented by the 'southern Proto-South China Sea' slab at 800 to 900 km depths. Our plate reconstruction implies the southern South China Sea was an active margin during South China Sea opening and had a south-facing arc and a north

Seismic geomorphology of the Lobed-channel System of Upper Miocene Huangliu Formation, Yinggehai Basin, Northwestern South China Sea

NASA Astrophysics Data System (ADS)

Liu, H.

2016-02-01

Three-dimensional seismic data have been widely used in interpreting ancient river systems and their associated sediment deposits. Thin-bed reservoirs of lobed-channel system in lithostratigraphic units of Dongfang (DF) area are one of the major study areas for reservoir growth in the Yinggehai basin of northwestern South China Sea. Although it is understood that the transport mechanics of parent substrate and alluvium determine the morphology of channel for lobed-channel system, the transport mechanism and regional gradient are relatively poorly understood. This study is focused on the application of various techniques in seismic geomorphology to the Yinggehai Basin at paleo-water-depth of 120m to assess influences of regional gradient and relative sea level change on lobed-channel palaeogeomorphology in shallow-water environments. The Vietnam paleo-Blue River, which located at south of modern Red River, flowed through DF area and transported turbidity deposit to DF area in the coastal environment. In 3-D seismic survey area, four fifth-order sequences in first member of upper Miocene Huangliu formation were identified using well and seismic data. Seismic inversion and 90° phasing of seismic data were used to convert seismic traces to pseudolithologic logs. Stratal slicing made it possible to interpolate and extrapolate well-data-derived sequence and identify submarine fan, channel fill, lobes and overbank deposit. Strata slices suggested that sea-floor slopes exerted main influence on channel morphology. Specifically, DF13-1 block had high gradient, which mainly distributed mud-sand-rich lobes. However, DF13-2 block established low gradient, which mostly indicated sand-rich braided channels. The values of sinuosity, channel widths, meander-belt widths in DF13-2 block are all greater than these in DF13-1 block. In addition, results of carbon isotope measurements and foraminiferal research of two blocks suggest that paleo sea level in DF13-2 block (30m 150m) was

Redkinian Biota of Macroscopic Fossils from the Northwestern East European Platform (South Ladoga Region)

NASA Astrophysics Data System (ADS)

Golubkova, E. Yu.; Kushim, E. A.; Kuznetsov, A. B.; Yanovskii, A. S.; Maslov, A. V.; Shvedov, S. D.; Plotkina, Yu. V.

2018-03-01

The stratigraphic distribution of microfossils and macroscopic fossil biota in Vendian deposits of the South Ladoga region (northwestern East European Platform) is analyzed. In the sequence of the Shotkusa- 1 well, three taxonomically heterogeneous microfossil assemblages are distinguished: two of them refer to the Redkinian age (Starorusskaya Fm.) and one to the Kotlinian age (Vasileostrovskaya Fm.). Deposits of the Starorusskaya Fm. contain Redkinian biota of macroscopic fossils, of which the most characteristic representatives are Chuaria circularis, Doushantuophyton lineare, Morania zinkovi, Orbisiana simplex, and Redkinia spinosa. These new findings expand the paleontological characteristics of Upper Vendian deposits, also providing additional criteria for distinguishing the Redkinian horizon in the northwestern East European Platform.

Winter precipitation change in South China in recent decades

NASA Astrophysics Data System (ADS)

Cai, Jingning

2013-04-01

Precipitation change is one of important climate researches in China, but winter precipitation variation in South China has not been studied so frequently. In China, it is rainy when hot; so summer precipitation is usually one focus in research, esp. in South China. However, winter precipitation and its change influence people profoundly in South China, also. The most recent example is what happened over South China in winter 2008. In this winter, millions of people suffered from the unusual cold and snowy winter. It led to huge loss in economy and traffic as well. Roads closed and railway stations were jammed and crowded with people; many planes were grounded for heavy snow and bad weather. Transmission lines faulted in the mountains. The ommunication signals were affected. Everyday food supply including vegetables and meats had to be delayed or interrupted. In some city even water supply was interrupted. And garbage in the city was piled up. Just in this winter the snow depth and coverage area in many places in South China broke or equaled the historical records. In fact, it isn't the only one unusual winter precipitation event in South China. Since 1950s, several freezing and snowy winters struck the South in China. In this research, winter precipitation change in recent years in South China has been discussed based on the precipitation observations. The associated large scale atmospheric circulation change is also analyzed. It is found that snowy winter in South China hardly comes in most periods of 2000s, but in recent decades this heavy snow in winter has appeared several times as observations shows. This phenomenon could be related to the large scale atmospheric circulation change.

Taxonomy and distribution of Terebellides (Polychaeta: Trichobranchidae) in the northern South China Sea, with description of three new species.

PubMed

Zhang, Jinghuai; Hutchings, Pat

2018-02-02

Benthic ecology monitoring in the northern South China Sea revealed many individuals of the polychaete genus Terebellides (Annelida), which are common in soft sediments in shallow waters (4.5-41.0 m). Three new species of Terebellides are described, including T. guangdongensis n. sp., T. yangi n. sp. and T. ectopium n. sp. Terebellides guangdongensis n. sp. is mainly found in Guangdong waters. Terebellides yangi n. sp. and T. ectopium n. sp. are mainly found in Beibu Gulf. A key to all described species of Terebellides from the Northwestern Pacific is given.

Chloroplast phylogeography of Helianthemum songaricum (Cistaceae) from northwestern China: implications for preservation of genetic diversity

Treesearch

Zhihao Su; Mingli Zhang; Stewart C. Sanderson

2011-01-01

Two chloroplast intergenic spacers (trnD-trnT and rps16-trnK) were used to study the phylogeographical structure of Helianthemum songaricum in northwestern China, with 12 haplotypes detected. Phylogenetic analysis showed that H. songaricum comprised two lineages, one distributed in the Yili Valley and the other in the western Ordos Plateau. Nested clade phylogeographic...

Community composition of picoeukaryotes in the South China Sea during winter

NASA Astrophysics Data System (ADS)

Lin, Yun-Chi; Chiang, Kuo-Ping; Kang, Lee-Kuo

2017-07-01

Picoeukaryotes, the smallest protists, are highly diverse and abundant in the ocean. However, little information is available about their community composition in the tropical northwestern Pacific Ocean. This study collected surface and deep chlorophyll maximum (DCM) waters from the South China Sea (SCS) to study the picoeukaryotic composition by constructing clone libraries of the 18S rRNA gene. The libraries were dominated by the heterotrophic organisms, alveolates and Rhizaria, which accounted for 46% and 16% of total clones, respectively. MALV-I was the most abundant group in alveolates, and Rhizaria appears to be a key organism in the SCS, particularly within DCM layers. These results indicate that parasitism is significant in the oligotrophic and tropical SCS. Apart from core-dinoflagellates, chlorophytes, haptophytes, cryptophytes and pelagophytes were other important contributors to primary production in pico-sized fraction based on quantitative and qualitative data.

A modeling study of the characteristics and mechanism of the westward coastal current during summer in the northwestern South China Sea

NASA Astrophysics Data System (ADS)

Ding, Yang; Bao, Xianwen; Yao, Zhigang; Zhang, Cong; Wan, Kai; Bao, Min; Li, Ruixiang; Shi, Maochong

2017-03-01

The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

Intensified pluvial conditions during the twentieth century in the inland Heihe River Basin in arid northwestern China over the past millennium

NASA Astrophysics Data System (ADS)

Qin, Chun; Yang, Bao; Burchardt, Iris; Hu, Xiaoli; Kang, Xingcheng

2010-06-01

Past streamflow variability is of special significance in the inland river basin, i.e., the Heihe River Basin in arid northwestern China, where water shortage is a serious environmental and social problem. However, the current knowledge of issues related to regional water resources management and long-term planning and management is limited by the lack of long-term hydro-meteorological records. Here we present a 1009-year annual streamflow (August-July) reconstruction for the upstream of the Heihe River in the arid northwestern China based on a well-replicated Qilian juniper ( Sabina przewalskii Kom.) ring-width chronology. This reconstruction accounts for 46.9% of the observed instrumental streamflow variance during the period 1958-2006. Considerable multidecadal to centennial flow variations below and above the long-term average are displayed in the millennium streamflow reconstruction. These periods 1012-1053, 1104-1212, 1259-1352, 1442-1499, 1593-1739 and 1789-1884 are noteworthy for the persistence of low-level river flow, and for the fact that these low streamflow events are not found in the observed instrumental hydrological record during the recent 50 years. The 20th century witnessed intensified pluvial conditions in the upstream of the Heihe River in the arid northwestern China in the context of the last millennium. Comparison with other long-term hydrological reconstructions indicates that the intensification of the hydrological cycle in the twentieth century from different regions could be attributable to regional to large-scale temperature increase during this time. Furthermore, from a practical perspective, the streamflow reconstruction can serve as a robust database for the government to work out more scientific and more reasonable water allocation alternatives for the Heihe River Basin in arid northwestern China.

Post partum depression and the psychosocial predictors in first-time fathers from northwestern China.

PubMed

Zhang, Yin-Ping; Zhang, Lu-Lu; Wei, Huan-Huan; Zhang, Yao; Zhang, Chun-Li; Porr, Caroline

2016-04-01

there is growing evidence that fathers also experience post partum depression (PPD). However, paternal PPD has been less studied than maternal PPD. Very few studies have investigated PPD in first-time fathers from northwestern China. the purpose of this study was to investigate the occurrence and predictors of depressive symptoms in first-time fathers from northwestern China. a longitudinal study was conducted involving 180 couples who were assessed at three time periods: 3 days, 2 weeks and 6 weeks after childbirth. Self-reported questionnaires including Edinburgh Postnatal Depression Scale (EPDS), Parenting Sense of Competence Scale (PSOC), and Kansas Marital Satisfaction Scale (KMSS) were administered to all participants during each time period. after childbirth 35 (21.1%) of the fathers at 3 days, 32 (20.4%) at 2 weeks and 20 (13.6%) at 6 weeks, indicated that they suffered from PPD. Paternal parental sense of competence, paternal marital satisfaction, and maternal depressive symptoms were among the main predictors for paternal PPD. the study results suggest that paternal PPD is a significant public health concern. Health professionals should focus attention on the psychological health among new fathers during the postpartum period; and, the psychosocial predictors should be considered and incorporated into clinical assessment and intervention of paternal PPD. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Oceanic Crustal Structure of the Southwestern Subbasin in the South China Sea

NASA Astrophysics Data System (ADS)

Wu, Z.; Ruan, A.; Li, J.; Lee, C.

2012-12-01

of Oceanography, SOA(Grant No. JT1101) References: Ruan A G, Qiu X L, Li J B, et al. Wide aperture seismic sounding in the margin seas of China. South China Journal of Seismology,2009,29:10-18(in Chinese). Li J B, Jin X L, Gao J Y. Morpho-tectonic study on late-stage spreading of the Eastern Subbasin of South China Sea. Sci China Ser D-Earth Sci,2002, 45:978-989 WU Z L, LI J B, RUAN A G, et al. Crustal structure of the northwestern sub-basin, South China Sea: Results from a wide-angle seismic experiment[J]. Sci China Earth Sci, 2012,55:159-172. doi: 10.1007/s11430-011-4324-9.

Impacts of plastic film mulching on crop yields, soil water, nitrate, and organic carbon in Northwestern China: A meta-analysis.

PubMed

Ma, Dedi; Chen, Lei; Qu, Hongchao; Wang, Yilin; Misselbrook, Tom; Jiang, Rui

2018-04-01

In order to increase crop yield in semi-arid and arid areas, plastic film mulching (PFM) is widely used in Northwestern China. To date, many studies have addressed the effects of PFM on soil physical and biochemical properties in rain-fed agriculture in Northwestern China, but the findings of different studies are often contradictory. Therefore, a comprehensive review of the impacts of PFM on soil water content, soil nutrients and food production is needed. We compiled the results of 1278 observations to evaluate the overall effects of PFM on soil water content, the distribution of nitrate and soil organic carbon, and crop yield in rain-fed agriculture in Northwestern China. Our results showed that PFM increased soil moisture and nitrate concentration in topsoils (0-20 cm) by 12.9% and 28.2%, respectively, but slightly decreased (1.8%) soil organic carbon (SOC) content in the 0-10 cm soil layer. PFM significantly increased grain yields by 43.1%, with greatest effect in spring maize (79.4%). When related to cumulative precipitation during the crop growing season, yield increase from PFM was greatest (72.8%) at 200-300 mm, which was attributed to the large increase for spring maize and potato, implying that crop zoning would be beneficial for PFM in this region. When related to N application rate, crop yields benefited most from PFM (80.2%) at 200-300 kg/ha. A cost-benefit analysis indicated that PFM increased economic return by an average of 29.5%, with the best improvement for spring maize (71.1%) and no increase for spring wheat. In conclusion, PFM can significantly increase crop yield and economic return (especially for spring maize) in rain-fed agriculture areas of Northwestern China. Crop zoning is recommended for PFM to achieve the largest economic benefit. However, full account needs to be taken of the environmental impacts relating to N loss, SOC depletion and film pollution to evaluate the sustainability of PFM systems and further research is

Deep-sea geohazards in the South China Sea

NASA Astrophysics Data System (ADS)

Wu, Shiguo; Wang, Dawei; Völker, David

2018-02-01

Various geological processes and features that might inflict hazards identified in the South China Sea by using new technologies and methods. These features include submarine landslides, pockmark fields, shallow free gas, gas hydrates, mud diapirs and earthquake tsunami, which are widely distributed in the continental slope and reefal islands of the South China Sea. Although the study and assessment of geohazards in the South China Sea came into operation only recently, advances in various aspects are evolving at full speed to comply with National Marine Strategy and `the Belt and Road' Policy. The characteristics of geohazards in deep-water seafloor of the South China Sea are summarized based on new scientific advances. This progress is aimed to aid ongoing deep-water drilling activities and decrease geological risks in ocean development.

Tectonic evolution of the Caribbean and northwestern South America: The case for accretion of two Late Cretaceous oceanic plateaus

NASA Astrophysics Data System (ADS)

Kerr, Andrew C.; Tarney, John

2005-04-01

It is widely accepted that the thickened oceanic crust of the Caribbean plate, its basaltic accreted margins, and accreted mafic terranes in northwestern South America represent the remnants of a single ca. 90 Ma oceanic plateau. We review geologic, geochemical, and paleomagnetic evidence that suggests that the Caribbean-Colombian oceanic plateau in fact represents the remnants of two different oceanic plateaus, both dated as ca. 90 Ma. The first of these plateaus, the Caribbean Plateau, formed ca. 90 Ma in the vicinity of the present-day Galapagos hotspot. Northeastward movement of the Farallon plate meant that this plateau collided with the proto Caribbean arc and northwestern South America <10 m.y. after the plateau's main phase of formation. Paleomagnetic evidence suggests that the second of these plateaus, the Gorgona Plateau, formed at 26° 30°S, possibly at the site of the present-day Sala y Gomez hotspot. Over the next ˜45 m.y., this plateau was carried progressively northeastward on the Farallon plate and collided in the middle Eocene with the proto Andean subduction zone in northwestern South America. The recognition of a second ca. 90 Ma Pacific oceanic plateau strengthens the link between plateau formation and global oceanic anoxic events.

Cenozoic plate reconstruction of the South China Sea region

NASA Astrophysics Data System (ADS)

Lee, Tung-Yi; Lawver, Lawrence A.

1994-07-01

Reconstructions of the South China Sea region at 60 Ma, 40 Ma, 30 Ma, 20 Ma, 10 Ma and 5 Ma are presented. We have attempted to place the South China Sea Basin in a regional tectonic framework. The tectonic evolution of the major blocks surrounding the South China Sea were analyzed, as well as the relative motions of the Indian and Australian plates. We have tried to correct the tectonic models available in this region. A 3-D graphics terminal was used to derive rotation poles for the different tectonic blocks and our model was then tested to determine its self-consistency. When the model conflicted with previous interpretations the input data were evaluated for alternative explanations. At least two, and possibly three, stages of extension can be recognized in this region. The earliest one, active in the Late Cretaceous to Eocene, involved NW-SE extension. The second one, active from the Late Eocene to Early Miocene involved north-south extension. The third stage of extension, which probably trended NW-SE, can be dated as post-Oligocene. The first extensional event produced the NE-SW trending proto-South China Sea and a series of sedimentary basins along the South China margin. Following the southeastward extrusion of Indochina, the proto-South China Sea was mostly consumed at the Palawan Trough. Renewed north-south extension in the South China continental margin started the present-day South China Sea spreading in the Oligocene. The southeastward extrusion of Indochina, blocked by Sundaland, resulted in the NW-SE trending opening of the South China Sea Basin in the Early Miocene. Collision of the North Palawan microcontinental block with the West Philippines block stopped the opening of the South China Sea at the end of Early Miocene. Spreading activity switched to the Sulu Sea Basin in the Middle Miocene but collision between the Sulu Ridge and the West Philippines at Mindanao halted the opening of the Sulu Sea at the end of the Middle Miocene. In the Late

A nearly modern amphibious bird from the Early Cretaceous of northwestern China.

PubMed

You, Hai-Lu; Lamanna, Matthew C; Harris, Jerald D; Chiappe, Luis M; O'connor, Jingmai; Ji, Shu-An; Lü, Jun-Chang; Yuan, Chong-Xi; Li, Da-Qing; Zhang, Xing; Lacovara, Kenneth J; Dodson, Peter; Ji, Qiang

2006-06-16

Three-dimensional specimens of the volant fossil bird Gansus yumenensis from the Early Cretaceous Xiagou Formation of northwestern China demonstrate that this taxon possesses advanced anatomical features previously known only in Late Cretaceous and Cenozoic ornithuran birds. Phylogenetic analysis recovers Gansus within the Ornithurae, making it the oldest known member of the clade. The Xiagou Formation preserves the oldest known ornithuromorph-dominated avian assemblage. The anatomy of Gansus, like that of other non-neornithean (nonmodern) ornithuran birds, indicates specialization for an amphibious life-style, supporting the hypothesis that modern birds originated in aquatic or littoral niches.

Spatio-temporal variability of lightning and convective activity over South/South-East Asia with an emphasis during El Niño and La Niña

NASA Astrophysics Data System (ADS)

Saha, Upal; Siingh, Devendraa; Midya, S. K.; Singh, R. P.; Singh, A. K.; Kumar, S.

2017-11-01

The present analysis investigates the spatio-temporal variability of the convective parameters and associated lightning flash rates during the period 1997-2013 including the El Niño and La Niña episode. It reveals that north-western and north-eastern part along the foothills of Himalayas as well as Indo-China peninsular region and South China Sea are much convective prone zones over the South/South-East Asia. The terrain/orography of the Himalayan range, the influence of cross-equatorial low-level jet and large-scale circulation during pre-monsoon and active phase of monsoon, the western Pacific Warm Pool with increased sea surface temperature as well as the solar-heating-originated local instability instigate the convective anomaly to propagate over the north-western and north eastern Indian sub-continent along with the Indo-China peninsula and South China Sea respectively. The land surfaces of the Indian sub-continent and the sea surface of South China Sea possesses significant correlation with lightning flash rates and convective parameters whereas the sea surface surrounding Indian sub-continent do not show such good correlations among them. Although, the occurrence of convective activities during the El Niño (La Niña) gets reduced (increased), the occurrence of lightning flashes gets enhanced (diminished) during this period which may be the direct consequence of warming atmosphere in relation to changing patterns of regional climate. Fig. S2 Spatial trend distribution per year of (a) LFR, (b) CAPE, (c) SCP, (d) LI, (e) CINE and (f) AT anomaly over South/South-East Asia during January-December for the years 1997-2013 (Trend is significant at 95% confidence level). Fig. S3 Correlation maps of LFR with (a) CAPE, (b) SCP, (c) CINE and (d) LI over South/South-East Asia during January-December for the years 1997-2013. Fig. S4 Synoptic wind direction patterns during (a)-(b) El Niño (May 2002 - February 2003) conditions and (c)-(d) La Niña (July 1998 - March

Phylogeography of the rare Gymnocarpos przewalskii (Caryophyllaceae): indications of multiple glacial refugia in north-western China

Treesearch

S. M. Ma; M. L. Zhang; S. C. Sanderson

2012-01-01

We investigated the phylogeography of Gymnocarpos przewalskii Maxim. (Caryophyllaceae), a rare relictual shrub restricted to north-western China, in the context of Quaternary climate oscillations. ThreecpDNAregions (psbA­trnH, ycf6­psbM and rpl32-trnL (UAG)) were sequenced for 160 individuals from 16 populations. High genetic diversity (hT = 0.930, hS = 0.425) and a...

Evidence of active mantle flow beneath South China

NASA Astrophysics Data System (ADS)

Wang, Chun-Yung; Flesch, Lucy M.; Chang, Lijun; Zheng, Tianyu

2013-10-01

The India-Eurasia collision is responsible for producing the Himalayan Mountains and Tibetan plateau and has been hypothesized to have significant far field influences, including driving the Baikal rift and the eastward extrusion of South China. However, quantification of lithospheric buoyancy forces and integrated effect of tractions acting at base of the lithosphere are unable to explain the observed surface motions within South China. We present 198 new SKS shear wave splitting observations beneath South China and invert these data along with published GPS data to solve for the subasthenospheric flow field beneath South China to assess the role of small-scale convection here. We find a 15-20 mm/yr southwestward-directed mantle flow toward the Burma slab. This flow is consistent with the mantle response of slab retreat over the past 25 Ma, and counter flow due to subduction of Burma/Sunda slabs demonstrating the importance of localized mantle convection on present-day plate motions.

Divergent population genetic structure of the endangered Helianthemum (Cistaceae) and its implication to conservation in northwestern China

Treesearch

Zhihao Su; Bryce A. Richardson; Li Zhuo; Xiaolong Jiang

2017-01-01

Population genetic studies provide a foundation for conservation planning, especially for endangered species. Three chloroplast SSRs (mtrnSf-trnGr, mtrnL2-trnF, and mtrnL5-trnL3) and the internal transcribed spacer were used to examine the population structure of Helianthemum in northwestern China. A total of 15 populations of the genus were collected. Nine chloroplast...

[Chemical characteristics of precipitation in South China Sea].

PubMed

Xiao, Hong-Wei; Long, Ai-Min; Xie, Lu-Hua; Xiao, Hua-Yun; Liu, Cong-Qiang

2014-02-01

Rainwater samples were collected in the summer on "Shiyan 3" during the 2012 South China Sea Sectional Scientific Survey. The concentrations of anion and cation, and pH in precipitation were determined and backward trajectories of air mass were simulated to analyze the chemical characteristics of ions and examine the source of ions. The results indicated that the mean pH value of precipitation was 6.3, with 5.6 of minimal value in summer in South China Sea. The order of anion and cation abundance was Cl(-) > S04(2-) > NO3(-) and Na(+) > Mg(2+) > Ca(2+) > K(+). Cl(-) was the major anion and Na(+) was the major cation, with concentrations of 2 637.5 microeq x L(-1) and 2095.5 microeq x L(-1), respectively, showing that they were the characteristics of marine atmospheric precipitation. There was a good linear relationship between each pair of 7 ions, with correlation coefficient above 0.9, suggesting that they may have a common source. However, the correlation coefficients were lower between NO3(-) and other ions than the others, suggesting that NO3(-) had more complex sources. The concentrations of Ca(2+) and K(+) in precipitation may be related to coral environment in South China Sea. The backward trajectories in 6 stations showed that the air mass was from south and southwest of South China Sea, without passing through above the continent. These results suggested that precipitation affected by human ion source can be ignored in summer in South China Sea.

Spatial relationships among species, above-ground biomass, N, and P in degraded grasslands in Ordus Plateau, northwestern China

Treesearch

X. Cheng; S. An; J. chen; B. Li; Y. Liu; S. Liu

2007-01-01

We chose five communities, representing a mild to severe gradient of grassland desertification in a semi-arid area of Ordos Plateau, northwestern China, to explore the spatial relationships among plant species, above-ground biomass (AGB), and plant nutrients (N and P). Community 1 (Cl) was dominated by Stipa bungeana; community 2 (C2) by a mix of S...

Cooperation from Strength: The United States, China and the South China Sea

DTIC Science & Technology

2012-01-01

the top of its diplomatic and security agenda. Freedom of navigation is a universal concern, and mari- time cooperation and mechanisms for...calls for new multilateral mechanisms for advancing stability and commerce. However, the South China Sea has also become the epicenter of what...multilateral mechanisms for resolving differing claims in the South China Sea.8 In the decades ahead, the challenge for the United States will be

Mesozoic Compressional Folds of the Nansha Waters, Southern South China Sea

NASA Astrophysics Data System (ADS)

Zhu, R.; Liu, H.; Yao, Y.; Wang, Y.

2017-12-01

As an important part of the South China Sea, the southern margin of the South China Sea is fundamental to understand the interaction of the Eurasian, Pacific and Indian-Australian plates and the evolution of the South China Sea. Some multi-channel seismic profiles of the Nansha waters together with published drillings and dredge data were correlated for interpretation. The strata of the study region can be divided into the upper, middle and lower structural layers. The upper and middle structural layers with extensional tectonics are Cenozoic; the lower structural layer suffered compression is Mesozoic. Further structural restoration was done to remove the Cenozoic tectonic influence and to calculate the Mesozoic tectonic compression ratios. The results indicate that two diametrically opposite orientations of compressive stress, S(S)E towards N(N)W orientation and N(N)W towards S(S)E orientation respectively, once existed in the lower structural layer of the study area and shared the same variation trend. The compression ratio values gradually decrease both from the north to the south and from the west to the east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate of the Nansha block drifted northward in Late Jurassic to Late Cretaceous, which had pushed the Nansha block drifted northward until it collided and sutured with the Southern China Margin. Thus the opening of the present-day South China Sea may be related to this suture zone, which was tectonically weakness zone.Key words: Mesozoic compression; structural restoration; proto-South China Sea; Nansha waters; Southern South China Sea; Acknowledgements: The work was granted by the National Natural Science Foundation of China (Grant Nos. 41476039, 91328205, 41576068 and 41606080).

Remediation of lead and cadmium from simulated groundwater in loess region in northwestern China using permeable reactive barrier filled with environmentally friendly mixed adsorbents.

PubMed

Fan, Chunhui; Gao, Yalin; Zhang, Yingchao; Dong, Wanqing; Lai, Miao

2018-01-01

Permeable reactive barrier (PRB) is potentially effective for groundwater remediation, especially using environmentally friendly mixed fillers in representative areas, such as semi-arid loess region in northwestern China. The mixed materials, including corn straw (agricultural wastes), fly ash (industrial wastes), zeolite synthesized from fly ash (reutilized products), and iron-manganese nodule derived from loess (materials with regional characteristics) in northwestern China, were chosen as PRB media to reduce the contents of lead and cadmium in simulated groundwater. A series of lab-scale column experiments were investigated, and the response surface methodology (RSM) was used to optimize the working process; Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were applied to further reveal the reaction mechanism. It shows that the purification efficiencies are more acceptable when the concentrations of lead and cadmium are approximately 7 and 0.7 mg/L, respectively, at 25 °C in weakly acidic solution, and functional groups of -OH and C=C play an important role for contaminants removal. The mixed adsorbents used are effective to remove lead and cadmium in groundwater. This is the first report on the removal of lead and cadmium from groundwater in loess region in northwestern China using PRB filled with environmentally friendly mixed adsorbents.

Using data of remote sensing to retrieve surface's evapotranspiration in northwest of China

NASA Astrophysics Data System (ADS)

Yu, Xinwen; Zheng, Youfei; Guo, Jianmao; He, Jinhai

2005-08-01

Northwestern China is a semi-arid or arid area in China. Ningnan (or South Ningxia) district is located south of Ningxia Province belong to Northwestern part of China. Climate in this region is more dry and lack of precipitation. Because global climate have been changing, temperature has been increasing and rainfall has been decreasing in South Ningxia. The ecology has been deteriorating, such as vegetation cover destroying, water losing and soil erosion. Therefore, the people who live in South Ningxia have been poor. Recently, Chinese government put into effect on strategy of "great development of Chinese northwest", aiming to improve environmental and ecological conditions and rise people's living standard. South Ningxia district was defined as area of emigration where the measurements of returning land for farming to forestry were taken into account . How to evaluate the plans and measurements is very important to continue to improving local environmental and ecological conditions further. The basic index of evaluation is soil water profit and loss statement while evapotranspiration (ET) is an important component in statement income and outcome of soil water. It is a very complicated problem to estimate evapotranspiration (ET) over large area of natural surface. In this paper, the natural surface was classified as 5 categories based on information from remote sensing, each categories being dealt with special way. Using data of remote sensing and weather stations, the result of regional evapotranspiration over Ningnan(South Ningxia) was given out, and verified and discussing are also made out. The work helps to assess whether or not improve environmental and ecological conditions.

Paleoclimatic and paleomagnetic constraints on the Paleozoic reconstructions of south China, north China and Tarim

NASA Astrophysics Data System (ADS)

Shangyou, Nie

1991-10-01

Paleomagnetic and paleoclimatic data provide the most useful latitudinal constraints for plate reconstructions. Distributions through the Paleozoic of five types of climatically sensitive sediments (coals, evaporites, reefs, dolomites and limestones) for south China, north China and Tarim are shown on 15 maps that include 1578 reliable data points. These paleoclimatic data agree reasonably well with available paleomagnetic directions, although significant divergence between the two exists for the Early Paleozoic. These data indicate the following: (1) South China was in low latitudes during the entire Paleozoic, with a subtropical position in the Cambrian. (2) North China also remained near the equator in the Early and Late Paleozoic, except for the Ordovian and the Late Permian when extensive evaporites suggest slightly higher latitudinal positions, while its Middle Paleozoic position is uncertain due to the missing stratigraphie record. (3) In south China, local tectonics appears to have played a dominant role in determining paleogeography and therefore marine sedimentation, especially after the Late Ordovician-Early Silurian, because the areal coverage of marine sediments through time is distinctly different from what would be expected from published global sea-level curves. (4) Paleoclimatic and paleomagnetic data are compatible with biogeographic data which suggest that south China was part of eastern Gondwana in the Early Paleozoic, but was widely separated from Gondwana in the Late Paleozoic, and the split between the two probably happened in the Devonian, giving rise to a major break-up unconformity in central south China.

Internal Waves, South China Sea

NASA Image and Video Library

1983-06-24

STS007-05-245 (18-24 June 1983) --- A rare view of internal waves in the South China Sea. Several different series of internal waves are represented in the 70mm frame, exposed with a handheld camera by members of the STS-7 astronaut crew aboard the Earth-orbiting Challenger. The land area visible in the lower left is part of the large island of Hainan, China.

New species of the giant deep-sea isopod genus Bathynomus (Crustacea, Isopoda, Cirolanidae) from Hainan Island, South China Sea.

PubMed

Kou, Qi; Chen, Jun; Li, Xinzheng; He, Lisheng; Wang, Yong

2017-07-01

Several specimens of the giant deep-sea isopod genus Bathynomus were collected by a deep-sea lander at a depth of 898 m near Hainan Island in the northern South China Sea. After careful examination, this material and the specimens collected from the Gulf of Aden, north-western Indian Ocean, previously reported as Bathynomus sp., were identified to be the same as a new species to the genus. Bathynomus jamesi sp. nov. can be distinguished from the congeners by: the distal margin of pleotelson with 11 or 13 short straight spines and central spine not bifid; uropodal endopod and exopod with distolateral corner slightly pronounced; clypeus with lateral margins concave; and antennal flagellum extending when extended posteriorly reaches the pereonite 3. In addition, Bathynomus jamesi sp. nov. is also supported by molecular analyses based on mitochondrial COI and 16S rRNA gene sequences. The distribution range of the new species includes the western Pacific and north-western Indian Ocean. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Crustal and upper-mantle structure of South China from Rayleigh wave tomography

NASA Astrophysics Data System (ADS)

Shan, B.; Xiong, X.; Zhao, K. F.; Xie, Z. J.; Zheng, Y.; Zhou, L.

2017-03-01

In this study, we image the crust and upper-mantle seismic velocity structures in South China using teleseismic Rayleigh waves recorded at 354 stations from the Chinese provincial networks (CEArray). We process Rayleigh wave data from 1087 teleseismic events and construct phase velocity maps at periods of 40-150 s. By combining dispersion curves at 6-70 s from Zhou et al. and at 40-150 s from the teleseismic surface wave tomography of this study, we construct a 3-D shear velocity model of the crust and upper mantle of South China. Distinct seismic structures are revealed from the eastern part of South China (including the South China Fold System and the eastern Yangtze Craton) to the western Yangtze Craton. The South China Fold System and eastern Yangtze Craton are characterized by lower velocities and shallow lithosphere-asthenosphere boundary (∼90 km), which are similar to the lithospheric thermal and seismic velocity structures of the North China basin. These observations may imply that the lithospheric destruction and thinning occurred not only beneath the North China Craton, but also beneath the eastern part of South China. The western Yangtze Craton, including the Sichuan Basin and Jiangnan Orogen, is underlain by a thicker and colder lithosphere with high velocities. The contrast of the lithosphere structure between the western Yangtze Craton and other parts of South China indicates that the lithospheric destruction and thinning of the east and southeast parts of South China may terminate at the boundary of the Jiangnan Orogen.

Shear wave anisotropy in northwestern South America and its link to the Caribbean and Nazca subduction geodynamics

NASA Astrophysics Data System (ADS)

Idárraga-García, J.; Kendall, J.-M.; Vargas, C. A.

2016-09-01

To investigate the subduction dynamics in northwestern South America, we measured SKS and slab-related local S splitting at 38 seismic stations. Comparison between the delay times of both phases shows that most of the SKS splitting is due to entrained mantle flow beneath the subducting Nazca and Caribbean slabs. On the other hand, the fast polarizations of local S-waves are consistently aligned with regional faults, which implies the existence of a lithosphere-confined anisotropy in the overriding plate, and that the mantle wedge is not contributing significantly to the splitting. Also, we identified a clear change in SKS fast directions at the trace of the Caldas Tear (˜5°N), which represents a variation in the subduction style. To the north of ˜5°N, fast directions are consistently parallel to the flat subduction of the Caribbean plate-Panama arc beneath South America, while to the south fast polarizations are subparallel to the Nazca-South America subduction direction. A new change in the SKS splitting pattern is detected at ˜2.8°N, which is related to another variation in the subduction geometry marked by the presence of a lithosphere-scale tearing structure, named here as Malpelo Tear; in this region, NE-SW-oriented SKS fast directions are consistent with the general dip direction of the underthrusting of the Carnegie Ridge beneath South America. Further inland, this NE-SW-trending mantle flow continues beneath the Eastern Cordillera of Colombia and Merida Andes of Venezuela. Finally, our results suggest that the subslab mantle flow in northwestern South America is strongly controlled by the presence of lithospheric tearing structures.

Interdecadal Change in SST Anomalies Associated with Winter Rainfall over South China

NASA Astrophysics Data System (ADS)

Liantong, Z.

2012-04-01

The present study investigates the interdecadal change in winter (January-February-March, or "JFM") rainfall over South China and in South China JFM rainfall-sea surface temperature (SST) relationship by using station observations for the period of 1958-2002, the Met Office Hadley Center's SST data for the period of 1900-2008, and the ERA-40 re-analysis for the period of 1958-2002. It is found that the relationship between South China JFM rainfall and SST experienced an obvious interdecadal change around the year 1978. The analyses show that the JFM rainfall anomalies during 1960-1977 and 1978-2002 were closely associated with the South China Sea (SCS) SST and El Niño-Southern Oscillation (ENSO), respectively. Moreover, southwesterly anomalies at 700 hPa dominate over the South China Sea for positive SCS SST anomaly years during 1960-1977, and for El Niño years during 1978-2002, respectively. These wind anomalies, which are associated with the enhancement of the western Pacific subtropical high, transport more moisture into South China, favoring increases in rainfall. KEY WORDS: ENSO; SCS SST; South China winter rainfall, western Pacific subtropical high.

Quantifying the Intra-Regional Precipitation Variability in Northwestern China over the Past 1,400 Years

PubMed Central

Lee, Harry F.; Pei, Qing; Zhang, David D.; Choi, Kan P. K.

2015-01-01

There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on “deducing regional resemblance” rather than “exploring regional variance.” To date, efforts to produce a quantitative assessment of long-term intra-regional precipitation variability (IRPV) in NW China has been inadequate. In the present study, we base on historical flood/drought records to compile a decadal IRPV index for NW China spanned AD580–1979 and to find its major determinants via wavelet analysis. Results show that our IRPV index captures the footprints of internal hydro-climatic disparity in NW China. In addition, we find distinct ~120–200 year periodicities in the IRPV index over the Little Ice Age, which are attributable to the change of hydro-climatic influence of ocean-atmospheric modes during the period. Also, we offer statistical evidence of El Niño Southern Oscillation (Indo-Pacific warm pool sea surface temperature and China-wide land surface temperature) as the prominent multi-decadal to centennial (centennial to multi-centennial) determinant of the IRPV in NW China. The present study contributes to the quantitative validation of the long-term IRPV in NW China and its driving forces, covering the periods with and without instrumental records. It may help to comprehend the complex hydro-climatic regimes in the region. PMID:26154711

Nature, diversity of deposit types and metallogenic relations of South China

USGS Publications Warehouse

Zaw, K.; Peters, S.G.; Cromie, P.; Burrett, C.; Hou, Z.

2007-01-01

The South China Region is rich in mineral resources and has a wide diversity of deposit types. The region has undergone multiple tectonic and magmatic events and related metallogenic processes throughout the earth history. These tectonic and metallogenic processes were responsible for the formation of the diverse styles of base and precious metal deposits in South China making it one of the resource-rich regions in the world. During the Proterozoic, the South China Craton was characterised by rifting of continental margin before eruption of submarine volcanics and development of platform carbonate rocks, and the formation of VHMS, stratabound copper and MVT deposits. The Phanerozoic metallogeny of South China was related to opening and closing of the Tethyan Ocean involving multiple orogenies by subduction, back-arc rifting, arc-continent collision and post-collisional extension during the Indosinian (Triassic), Yanshanian (Jurassic to Cretaceous) and Himalayan (Tertiary) Orogenies. The Late Palaeozoic was a productive metallogenic period for South China resulting from break-up and rifting of Gondwana. Significant stratabound base and precious metal deposits were formed during the Devonian and Carboniferous (e.g., Fankou and Dabaoshan deposits). These Late Palaeozoic SEDEX-style deposits have been often overprinted by skarn systems associated with Yanshanian magmatism (e.g., Chengmenshan, Dongguashan and Qixiashan). A number of Late Palaeozoic to Early Mesozoic VHMS deposits also developed in the Sanjiang fold belt in the western part of South China (e.g., Laochang and Gacun). South China has significant sedimentary rock-hosted Carlin-like deposits, which occur in the Devonian- to Triassic-aged accretionary wedge or rift basins at the margin of the South China Craton. They are present in a region at the junction of Yunnan, Guizhou, and Guangxi Provinces called the 'Southern Golden Triangle', and are also present in NW Sichuan, Gansu and Shaanxi, in an area known as

Environmental impacts of large-scale CSP plants in northwestern China.

PubMed

Wu, Zhiyong; Hou, Anping; Chang, Chun; Huang, Xiang; Shi, Duoqi; Wang, Zhifeng

2014-01-01

Several concentrated solar power demonstration plants are being constructed, and a few commercial plants have been announced in northwestern China. However, the mutual impacts between the concentrated solar power plants and their surrounding environments have not yet been addressed comprehensively in literature by the parties involved in these projects. In China, these projects are especially important as an increasing amount of low carbon electricity needs to be generated in order to maintain the current economic growth while simultaneously lessening pollution. In this study, the authors assess the potential environmental impacts of large-scale concentrated solar power plants. Specifically, the water use intensity, soil erosion and soil temperature are quantitatively examined. It was found that some of the impacts are favorable, while some impacts are negative in relation to traditional power generation techniques and some need further research before they can be reasonably appraised. In quantitative terms, concentrated solar power plants consume about 4000 L MW(-1) h(-1) of water if wet cooling technology is used, and the collectors lead to the soil temperature changes of between 0.5 and 4 °C; however, it was found that the soil erosion is dramatically alleviated. The results of this study are helpful to decision-makers in concentrated solar power site selection and regional planning. Some conclusions of this study are also valid for large-scale photovoltaic plants.

POWER AND CULTURE IN THE SOUTH CHINA SEA

DTIC Science & Technology

2016-02-16

Confucian strategic culture and offensive realism, to assess Chinese behavior in three test cases: Paracel Islands in 1974, Fiery Cross Reef and Johnson ...pursuing an island -building campaign across the South China Sea in support of its sovereignty claims that date from 1951. This is a contested air...these two competing lenses to evaluate PRC behavior in the South China Sea using three separate cases: Paracel Islands in 1974, Fiery Cross Reef and

Crustal structure and inferred extension mode in the northern margin of the South China Sea

NASA Astrophysics Data System (ADS)

Gao, J.; Wu, S.; McIntosh, K. D.; Mi, L.; Spence, G.

2016-12-01

Combining multi-channel seismic reflection and satellite gravity data, this study has investigated the crustal structure and magmatic activities of the northern South China Sea (SCS) margin. Results show that a broad continent-ocean transition zone (COT) with more than 140 km wide is characterized by extensive igneous intrusion/extrusion and hyper-extended continental crust in the northeastern SCS margin, a broader COT with 220-265 km wide is characterized by crustal thinning, rift depression, structural highs with igneous rock and perhaps a volcanic zone or a zone of tilted fault blocks at the distal edge in the mid-northern SCS margin, and a narrow COT with 65 km wide bounded seawards by a volcanic buried seamount is characterized by extremely hyper-extended continental crust in the northwestern SCS margin, where the remnant crust with less than 3 km thick is bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a sub-parallel fossil ridge in the adjacent Northwest Sub-basin. Results from gravity modeling and seismic refraction data show that a high velocity layer (HVL) is present in the outer shelf and slope below extended continental crust in the eastern portion of the northern SCS margin and is thickest (up to 10 km) in the Dongsha Uplift where the HVL gradually thins to east and west below the lower slope and finally terminates at the Manila Trench and Baiyun sag of the Pearl River Mouth Basin. The magmatic intrusions/extrusions and HVL may be related to partial melting caused by decompression of passive, upwelling asthenosphere which resulted primarily in post-rifting underplating and magmatic emplacement or modification of the crust. The northern SCS margin is closer to those of the magma-poor margins than those of volcanic margins, but the aborted rift near the northwestern continental margin shows that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric aborted

Atmospheric short-chain chlorinated paraffins in China, Japan, and South Korea.

PubMed

Li, Qilu; Li, Jun; Wang, Yan; Xu, Yue; Pan, Xiaohui; Zhang, Gan; Luo, Chunling; Kobara, Yuso; Nam, Jae-Jak; Jones, Kevin C

2012-11-06

This study presents the first investigation of concentrations and congener group patterns of atmospheric short-chain chlorinated paraffins (SCCPs) throughout East Asia. Based on an absorption rate calibration experiment, a spatial survey of SCCPs was performed using passive air samplers in China, Japan, and South Korea during two separate periods in 2008. The atmospheric concentrations of SCCPs in China were clearly greater than those in Japan and South Korea, both of which exceed the levels determined for other regions of the world. C(10) components were the most abundant type of SCCPs in China, whereas C(11) components were dominant in Japan and South Korea. With respect to the total chlorine content, Cl(6) and Cl(5) were the predominant compounds in China and Japan; however, Cl(6) and Cl(7) were predominant in South Korea. A similar pattern was also found for remote sites within China, Japan, and South Korea, respectively. Together with the back-trajectories calculated for the remote sites, the results indicate that the SCCPs in the air of East Asia were mainly influenced by local sources due to their relatively low long-range atmospheric transport potential compared to other POPs.

Investigating Effects of Monsoon Winds on Hydrodynamics in the South China Sea

NASA Astrophysics Data System (ADS)

Chua, V. P.

2013-12-01

The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. The circulation in South China Sea is subjected to seasonal and inter-annual variations of tidal and meteorological conditions. The effects of monsoon winds on hydrodynamics is investigated by applying spectral and harmonic analysis on surface elevation and wind data at stations located in the South China Sea. The analysis indicates varying responses to the seasonal monsoon depending on the location of the station. At Kaohsiung (located in northern South China Sea off Taiwan coast), tides from the Pacific Ocean and the southwest monsoon winds are found to be dominant mechanisms. The Kota Kinabalu and Bintulu stations, located to the east of South China Sea off Borneo coast, are influenced by low energy complex winds, and the shallow bottom bathymetry at these locations leads to tidal energy damping compared to other stations. The tidal dynamics at Tioman, located in southern South China Sea off Malaysia coast, are most responsive to the effects of the northeast monsoon. The complexity of our problem together with the limited amount of available data in the region presents a challenging research topic. An unstructured-grid SUNTANS model is employed to perform three-dimensional simulations of the circulation in South China Sea. Skill assessment of the model is performed by comparing model predictions of the surface elevations and currents with observations. The results suggest that the quality of the model prediction is highly dependent on horizontal grid resolution and coastline accuracy. The model may be used in future applications to investigate seasonal and inter-annual variations in hydrodynamics.

First genotyping of Blastocystis sp. in dairy, meat, and cashmere goats in northwestern China.

PubMed

Song, Jun-Ke; Yin, Yan-Ling; Yuan, Ya-Jie; Tang, Huan; Ren, Guan-Jing; Zhang, Hui-Jun; Li, Zi-Xuan; Zhang, Yan-Ming; Zhao, Guang-Hui

2017-12-01

Blastocystis is one of the most common parasites inhabiting in small intestines of human and animals. Although its pathogenicity has been remaining controversial, the possibility of zoonotic transmission between human and animals was recognized. The goat was one of the most important economic animals supplying people with cashmere, meat, and dairy products. However, few studies were to investigate Blastocystis infection in goats. A total of 789 faecal specimens of goats (including 362 of dairy, 193 of meat and 234 of cashmere goats) were collected from multiple regions of Shaanxi province in northwestern China to investigate the colonization frequency and subtypes of Blastocystis, and to assess the zoonotic potential of these goats. The respective colonization frequencies of Blastocystis in dairy, meat and cashmere goats were 54.1% (196/362), 40.4% (78/193) and 78.6% (184/234). The prevalence of Blastocystis in pre-weaned (0-2-month) goats was significantly lower than that in goats of other age groups, and the highest colonization was observed in goats of 7-11-month age group. Sequence analysis of Blastocystis positive samples indicated the presence of seven subtypes in these goats, including six known subtypes (STs1, 3, 4, 5, 10, 14) and one possible novel subtype (isolate Sd26), with the subtype 10 as the predominant one. Additionally, zoonotic subtypes were found in dairy (ST1, ST3 and ST5) and cashmere (ST4 and ST5) goats, but not detected in meat goats. These results showed that Blastocystis is highly prevalent, widely distributed and genetically diverse in goats in Shaanxi province, northwestern China, and zoonotic potential of dairy and cashmere goats to transmit Blastocystis. Copyright © 2017 Elsevier B.V. All rights reserved.

Cretaceous-Eocene provenance connections between the Palawan Continental Terrane and the northern South China Sea margin

NASA Astrophysics Data System (ADS)

Shao, Lei; Cao, Licheng; Qiao, Peijun; Zhang, Xiangtao; Li, Qianyu; van Hinsbergen, Douwe J. J.

2017-11-01

The plate kinematic history of the South China Sea opening is key to reconstructing how the Mesozoic configuration of Panthalassa and Tethyan subduction systems evolved into today's complex Southeast Asian tectonic collage. The South China Sea is currently flanked by the Palawan Continental Terrane in the south and South China in the north and the two blocks have long been assumed to be conjugate margins. However, the paleogeographic history of the Palawan Continental Terrane remains an issue of uncertainty and controversy, especially regarding the questions of where and when it was separated from South China. Here we employ detrital zircon U-Pb geochronology and heavy mineral analysis on Cretaceous and Eocene strata from the northern South China Sea and Palawan to constrain the Late Mesozoic-Early Cenozoic provenance and paleogeographic evolution of the region testing possible connection between the Palawan Continental Terrane and the northern South China Sea margin. In addition to a revision of the regional stratigraphic framework using the youngest zircon U-Pb ages, these analyses show that while the Upper Cretaceous strata from the Palawan Continental Terrane are characterized by a dominance of zircon with crystallization ages clustering around the Cretaceous, the Eocene strata feature a large range of zircon ages and a new mineral group of rutile, anatase, and monazite. On the one hand, this change of sediment compositions seems to exclude the possibility of a latest Cretaceous drift of the Palawan Continental Terrane in response to the Proto-South China Sea opening as previously inferred. On the other hand, the zircon age signatures of the Cretaceous-Eocene strata from the Palawan Continental Terrane are largely comparable to those of contemporary samples from the northeastern South China Sea region, suggesting a possible conjugate relationship between the Palawan Continental Terrane and the eastern Pearl River Mouth Basin. Thus, the Palawan Continental

Recent Seismic Experiments of OBS in the South China Sea

NASA Astrophysics Data System (ADS)

Ruan, A.; Li, J.; Wu, Z.

2012-12-01

Since 2006 some research institutions of China have carried out some important seismic experiments by using ocean bottom seismometer(OBS) in the South China Sea (SCS) and obtained many concrete progresses in modeling the crustal structure of SCS and also in understanding of its formation and evolution as well. In 2006 three wide-angle profiles were completed in the northern margin, named OBS2006-1 across the northwestern sub-basin, OBS2006-2 parallel to the sea basin boundary and OBS2006-3 across the Dongsha Rise and Chaoshan Depression respectively. In 2010 two wide- angle profiles were completed, named OBS2010-1 and OBS 2010-2 both perpendicular to the northern off-shore faulting system. During 2009-2011 four wide-angle profiles were completed in the southern margin, named OBS973-1 from southern margin to the southwestern sub-basin, OBS973-2 from Liyue Bank to the southwestern sub-basin and OBS973-3 from Xisha to the southwestern sub-basin, OBS2011-2 from Xisha to Hainan Island respectively. In 2011 two 3D seismic array of OBS were completed in the Zhongnan-Changlong sea mount chain and Huangyan-Zhenbei sea mount chain respectively. Here we present some primary but important results as follows. (1) The velocity model of OBS2006-1 indicates that the crust under the continental slope decreases from 21km to 11km, and to 7.7km in the northwestern sub-basin with Moho depth ascends from 21km to 11km. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins on both sides shows symmetrical and conjugate and indicates pure shear mode of continental margin rifting mechanism. (2) The velocity model of OBS2006-3 reveals remarkable thickness with maximum 8 km of the Mesozoic sediment in Chaoshan Depression in which velocity increases downward from 4.4 km/s at top to 5.3 km/s at the bottom. The buried depth of Moho decreases from 24-25 km under Dongsha Rise to 17 km in the lower slope and an obviously velocity abnormal is detected in the upper

Planaxidae (Mollusca, Gastropoda) from the South China Sea

NASA Astrophysics Data System (ADS)

Chen, Zhiyun; Zhang, Junlong; Lian, Xiping; Tan, Yehui

2018-03-01

Planaxidae is a family of tropical and subtropical marine gastropods that are adapted to an intertidal, rocky environment. The present study deals with three species in the family Planaxidae from the South China Sea: Planaxis sulcatus (von Born, 1778), Angiola longispira (Smith, 1872), and Supplanaxis niger (Quoy and Gaimard, 1833), based on specimens deposited in the Marine Biodiversity Collections of the South China Sea, Chinese Academy of Sciences. The taxonomic status, main morphological characteristics of the shell and radula, distribution, and habitat of these three planaxid species are presented. We also briefly discuss their morphological differences and the biogeographic distribution.

A fall land bird migration across the South China Sea from Indo-China to the Greater Sunda Islands

USGS Publications Warehouse

Ellis, D.H.; Kepler, A.K.; Kepler, C.B.

1994-01-01

We encountered 150 land birds representing 14 families along the cruise track of the Soviet Oceanographic Research Vessel AKADEMlK KOROLEV in the South China Sea. We saw most of these birds during a 3 -day period in a small area c. 350 km southeast of the southern tip of the Indo-China peninsula. These observations suggest that a significant land bird migration corridor crosses the South China Sea from Viet Nam to Borneo.

[Analysis of pathogen spectrum of Encephalitis/Meningitis in northwestern area of China].

PubMed

Zhang, Xiao-shu; Wang, Xu-xia; Yu, De-shan; Jiang, Jian-xiang; Zhang, Guang-ye; Wang, Fang; Li, Hui

2013-10-01

To learn the characteristics of pathogen spectrum of Encephalitis /Meningitis in northwestern area of China. Between January 1st 2009 and March 31st 2011, a total of 569 patients with clinical symptoms of Encephalitis/Meningitis were selected from the hospitals in Gansu, Qinghai,Inner Mongolia and Xinjiang province. 1514 samples of specimen were collected from the 515 patients, to detect the IgM of Japanese encephalitis virus (JEV), enterovirus (EV, including Coxsackie virus, ECHO virus and enterovirus 71), Mumps virus, Herpes simplex virus (HSV) in blood and cerebrospinal fluid. Meanwhile, Neisseria meningitis (Nm), Haemophilus influenzae Type B (Hib), Staphylococcus, Streptococcus pneumonia, Streptococcus Suis, E. Coli and Cryptococci were also identified. The detection results were analyzed by different region, time and age range. Pathogenic bacteria were identified in the specimen from 16 patients, with the rate at 3.65%, of which the dominant ones were Streptococcus pneumonia (7 patients, 43.75%). Virus were identified in the specimen from 132 patients, with the rate at 27.05%, of which the dominant types were EV and HSV, accounting for 33.33% (44 cases) and 31.82% (42 cases) respectively. The detection rate of virus showed a significant seasonal trend, with the peak appearing between June and November each year. The peak of EV detection was between July and September, with 24 cases detected out; the peak of HSV was between June and August (11 cases detected out); mumps virus was mainly found between July and December (25 cases). There was no significant time-distribution found in the detection of bacteria. The EV and HSV were mainly distributed in Gansu and Qinghai province (70 cases) ;most of mumps virus were found in Gansu province (24 cases);and JEV were only found in Gansu province (20 cases). The viral pathogen spectrum was identified in all ages, and the EV and mumps virus were mainly found in children aged 0-14 years old (42 and 17 cases respectively

Countermeasure Study on Deep-sea Oil Exploitation in the South China Sea——A Comparison between Deep-sea Oil Exploitation in the South China Sea and the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Zhao, Hui; Qiu, Weiting; Qu, Weilu

2018-02-01

The unpromising situation of terrestrial oil resources makes the deep-sea oil industry become an important development strategy. The South China Sea has a vast sea area with a wide distribution of oil and gas resources, but there is a phenomenon that exploration and census rates and oil exploitation are low. In order to solve the above problems, this article analyzes the geology, oil and gas exploration and exploration equipment in the South China Sea and the Gulf of Mexico. Comparing the political environment of China and the United States energy industry and the economic environment of oil companies, this article points out China’s deep-sea oil exploration and mining problems that may exist. Finally, the feasibility of oil exploration and exploitation in the South China Sea is put forward, which will provide reference to improve the conditions of oil exploration in the South China Sea and promoting the stable development of China’s oil industry.

Estimation of potential distribution of gas hydrate in the northern South China Sea

NASA Astrophysics Data System (ADS)

Wang, Chunjuan; Du, Dewen; Zhu, Zhiwei; Liu, Yonggang; Yan, Shijuan; Yang, Gang

2010-05-01

Gas hydrate research has significant importance for securing world energy resources, and has the potential to produce considerable economic benefits. Previous studies have shown that the South China Sea is an area that harbors gas hydrates. However, there is a lack of systematic investigations and understanding on the distribution of gas hydrate throughout the region. In this paper, we applied mineral resource quantitative assessment techniques to forecast and estimate the potential distribution of gas hydrate resources in the northern South China Sea. However, current hydrate samples from the South China Sea are too few to produce models of occurrences. Thus, according to similarity and contrast principles of mineral outputs, we can use a similar hydrate-mining environment with sufficient gas hydrate data as a testing ground for modeling northern South China Sea gas hydrate conditions. We selected the Gulf of Mexico, which has extensively studied gas hydrates, to develop predictive models of gas hydrate distributions, and to test errors in the model. Then, we compared the existing northern South China Sea hydrate-mining data with the Gulf of Mexico characteristics, and collated the relevant data into the model. Subsequently, we applied the model to the northern South China Sea to obtain the potential gas hydrate distribution of the area, and to identify significant exploration targets. Finally, we evaluated the reliability of the predicted results. The south seabed area of Taiwan Bank is recommended as a priority exploration target. The Zhujiang Mouth, Southeast Hainan, and Southwest Taiwan Basins, including the South Bijia Basin, also are recommended as exploration target areas. In addition, the method in this paper can provide a useful predictive approach for gas hydrate resource assessment, which gives a scientific basis for construction and implementation of long-term planning for gas hydrate exploration and general exploitation of the seabed of China.

Mitigating the Security Risks in the South China Sea Island Disputes

DTIC Science & Technology

2014-02-13

research paper are those of the author and do not reflect the official policy or position of the US government, the Department of Defense, or Air...interplay between China’s strategy and US policy for the South China Sea disputes. This paper will argue that the security situation in the South China Sea...The paper will also examine how and why the US rebalance to Asia has caused China adopt a change in tactics but continue its strategy of delay

Green auctions and reduction of information rents in payments for environmental services: an experimental investigation in Sunan County, northwestern China.

PubMed

Deng, Xiaohong; Xu, Zhongmin

2015-01-01

Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the "Grain for Green" Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. "Perfect information" in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions.

Spatial Analysis of Air Quality Monitor Data in China, Japan, and South Korea

NASA Astrophysics Data System (ADS)

Rohde, Robert

2016-04-01

In 2015, Berkeley Earth published a widely-reported study concluding that air pollution contributes to 1.6 million deaths per year in China. This presentation will provide an update on that work with additional data for China and new analysis for South Korea and Japan. In China, two years of data from more than 1500 monitoring stations allows local trends to be estimated. Preliminary review indicates a trend towards improving air quality across most of China with decreasing emissions at most major population centers. Such improvements are consistent with tightening emissions standards and the decreasing usage of coal. In addition, new spatial analysis has been applied to ~900 monitoring sites in Japan and ~120 sites in South Korea. This new analysis provides information on air quality, pollutant source distributions, and implied mortality in these countries. Finally, boundary crossing fluxes in South Korea and Japan have been used to estimate the fraction of air pollution in Japan and South Korea that has being imported from sources in China.

On the tidally driven circulation in the South China Sea: modeling and analysis

NASA Astrophysics Data System (ADS)

Nelko, Varjola; Saha, Abhishek; Chua, Vivien P.

2014-03-01

The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. An unstructured-grid SUNTANS model is employed to perform depth-averaged simulations of the circulation in the South China Sea. The model is tidally forced at the open ocean boundaries using the eight main tidal constituents as derived from the OSU Tidal Prediction Software. The model simulations are performed for the year 2005 using a time step of 60 s. The model reproduces the spring-neap and diurnal and semidiurnal variability in the observed data. Skill assessment of the model is performed by comparing model-predicted surface elevations with observations. For stations located in the central region of the South China Sea, the root mean squared errors (RMSE) are less than 10 % and the Pearson's correlation coefficient ( r) is as high as 0.9. The simulations show that the quality of the model prediction is dependent on the horizontal grid resolution, coastline accuracy, and boundary locations. The maximum RMSE errors and minimum correlation coefficients occur at Kaohsiung (located in northern South China Sea off Taiwan coast) and Tioman (located in southern South China Sea off Malaysia coast). This may be explained with spectral analysis of sea level residuals and winds, which reveal dynamics at Kaohsiung and Tioman are strongly influenced by the seasonal monsoon winds. Our model demonstrates the importance of tidally driven circulation in the central region of the South China Sea.

Dissolved inorganic phosphorus, dissolved iron, and Trichodesmium in the oligotrophic South China Sea

NASA Astrophysics Data System (ADS)

Wu, Jingfeng; Chung, Shi-Wei; Wen, Liang-Saw; Liu, Kon-Kee; Chen, Yuh-Ling Lee; Chen, Houng-Yung; Karl, David M.

2003-03-01

Dissolved inorganic phosphorus (DIP) concentrations in the oligotrophic surface waters of the South China Sea decrease from ˜20 nM in March 2000 to ˜5 nM in July 2000, in response to seasonal water column stratification. These minimum DIP concentrations are one order of magnitude higher than those in the P-limited, iron-replete stratified surface waters of the western North Atlantic, suggesting that the ecosystem in the South China Sea may be limited by bioavailable nitrogen or some trace nutrient rather than DIP. Nutrient enrichment experiments using either nitrate, phosphate or both indicate that nitrogen limits the net growth of phytoplankton in the South China Sea, at least during March and July 2000. The fixed nitrogen limitation may result from the excess phosphate (N:P<16) transported into the South China Sea from the North Pacific relative to microbial population needs, or from iron control of nitrogen fixation. The iron-limited nitrogen fixation hypothesis is supported by the observation of low population densities of Trichodesmium spp. (<48 × 103 trichomes/m3), the putative N2 fixing cyanobacterium, and with low concentrations of dissolved iron (˜0.2-0.3 nM) in the South China Sea surface water. Our results suggest that nitrogen fixation can be limited by available iron even in regions with a high rate of atmospheric dust deposition such as in the South China Sea.

Internal Waves, South China Sea

NASA Technical Reports Server (NTRS)

1983-01-01

Subsurface ocean currents, frequently referred to as internal waves, are frequently seen from space under the right lighting conditions when depth penetration can be achieved. These internal waves observed in the South China Sea off the SE coast of the island of Hainan (18.5N, 110.5E) visibly demonstrate turbidity in the ocean's depths at the confluence of conflicting currents.

Rayleigh wave tomography in South China from ambient seismic noise cross-correlation

NASA Astrophysics Data System (ADS)

Xu, S.; Song, X.; Wang, L.; Xu, M.

2012-12-01

South China is a composite of continental blocks with relics of Proterozoic and late-Paleozoic sutures, and underwent complex transformations in geological history. The connection of Yangtze Block (YZB) and Cathaysian Block (CTB) around 1 Ga led to Neoproterozoic rift systems in the central South China. Subsequently, strong folding and thrusting with intracontinental shortening occurred in the central South China during Mesozoic as a response to the collision of China-Indochina with Philippine Plate. Post orogenesis during Jurassic and Cretaceous, accompanied by extension and delamination, led to the thinning of lithosphere and granite intrusion, which becomes the main mineralization process in South China. The mechanism of the intracontinental collision and boundary of YZB with CTB have been debated for a long time. Detailed lithospheric structures are important for us to understand characteristics of the continental blocks, their boundaries, and the evolution processes. We use ambient noise cross-correlation method to obtain high resolution 3-D velocity images of South China. Continuous records of 298 stations from January 2010 to June 2011 are used to retrieve Rayleigh wave Green functions between possible station pairs. Waveform and dispersion curve comparisons with earthquake-emitted Rayleigh wave indicate that the ambient noise method is efficient and reliable. Both group and phase velocity images of 0.5°×0.5° grid from 8 to 40 s are estimated. Then, shear velocities are inversed in each grid, using a recent regional S-velocity model as a constraint for deeper structures. The surface wave maps in short periods clearly delineate basins and mountains. Deeper Moho in west of South China is observed, which can be interpreted as a result of strata folding and shortening in Mesozoic or long-range effects from Indian-Asian collision in Cenozoic. The collision mode between YZB and CTB is different for Lower-YZB (L-YZB) and Upper-YZB (U-YZB): the L-YZB is a simple

Near-surface air temperature lapse rates in Xinjiang, northwestern China

NASA Astrophysics Data System (ADS)

Du, Mingxia; Zhang, Mingjun; Wang, Shengjie; Zhu, Xiaofan; Che, Yanjun

2018-02-01

Lapse rates of near-surface (2 m) air temperature are important parameters in hydrologic and climate simulations, especially for the mountainous areas without enough in-situ observations. In Xinjiang, northwestern China, the elevations range from higher than 7000 m to lower than sea level, but the existing long-term meteorological measurements are limited and distributed unevenly. To calculate lapse rates in Xinjiang, the daily data of near-surface air temperature ( T min, T ave, and T max) were measured by automatic weather stations from 2012 to 2014. All the in situ observation stations were gridded into a network of 1.5° (latitude) by 1.5° (longitude), and the spatial distribution and the daily, monthly, seasonal variations of lapse rates for T min, T ave, and T max in Xinjiang are analyzed. The Urumqi River Basin has been considered as a case to study the influence of elevation, aspect, and the wet and dry air conditions to the T min, T ave, and T max lapse rates. Results show that (1) the lapse rates for T min, T ave, and T max vary spatially during the observation period. The spatial diversity of T min lapse rates is larger than that of T ave, and that of T max is the smallest. For each season, T max lapse rates have more negative values than T ave lapse rates which are steeper than T min lapse rates. The weakest spatial diversity usually appears in July throughout a year. (2) The comparison for the three subregions (North, Middle, and South region) exhibits that lapse rates have similar day-to-day and month-to-month characteristics which present shallower values in winter months and steeper values in summer months. The T ave lapse rates in North region are shallower than those in Middle and South region, and the steepest T ave lapse rates of the three regions all appear in April. T min lapse rates are shallower than T max lapse rates. The maximum medians of T min and T max lapse rates for each grid in the three regions all appear in January, whereas the

Opening of the South China Sea and Upwelling of the Hainan Plume

NASA Astrophysics Data System (ADS)

Yu, Mengming; Yan, Yi; Huang, Chi-Yue; Zhang, Xinchang; Tian, Zhixian; Chen, Wen-Huang; Santosh, M.

2018-03-01

Opening of the South China Sea and upwelling of the Hainan Plume are among the most challenging issues related to the tectonic evolution of East Asia. However, when and how the Hainan Plume affected the opening of the South China Sea remains unclear. Here we investigate the geochemical and isotopic features of the 25 Ma mid-ocean ridge basalt (MORB) in the Kenting Mélange, southern Taiwan, 16 Ma MORB drilled by the IODP Expedition 349, and 9 Ma ocean island basalt-type dredged seamount basalt. The 25 Ma MORBs reveal a less metasomatic depleted MORB mantle-like source. In contrast, the Miocene samples record progressive mantle enrichment and possibly signal the contribution of the Hainan Plume. We speculate that MORBs of the South China Sea which could have recorded plume-ridge source mixing perhaps appear since 23.8 Ma. On the contrary, the Paleocene-Eocene ocean island basalt-type intraplate volcanism of the South China continental margin is correlated to decompression melting of a passively upwelling fertile asthenosphere due to continental rifting.

Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

PubMed

Jiménez-Segura, L F; Galvis-Vergara, G; Cala-Cala, P; García-Alzate, C A; López-Casas, S; Ríos-Pulgarín, M I; Arango, G A; Mancera-Rodríguez, N J; Gutiérrez-Bonilla, F; Álvarez-León, R

2016-07-01

The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries. © 2016 The Fisheries Society of the British Isles.

Green Auctions and Reduction of Information Rents in Payments for Environmental Services: An Experimental Investigation in Sunan County, Northwestern China

PubMed Central

Deng, Xiaohong; Xu, Zhongmin

2015-01-01

Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the “Grain for Green” Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. “Perfect information” in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions. PMID:25793263

Optimizing Search Patterns for Multiple Searchers Prosecuting a Single Contact In the South China Sea

DTIC Science & Technology

2016-09-01

searching for lost car keys in a parking lot to prosecuting a submarine in the South China Sea. This research draws on oceanographic properties to...search area based on the oceanographic properties at 21N 119E. 14. SUBJECT TERMS Search Theory, Undersea Warfare, South China Sea, Anti- Submarine ...lot to prosecuting a submarine in the South China Sea. This research draws on oceanographic properties to develop a search radii for two surface ships

Broadband Seismic Array Observation along a ~2000-km-long Linear Profile in South China

NASA Astrophysics Data System (ADS)

Ai, Y.; Zhao, L.; Chen, L.; Zheng, T.; He, Y.; Jiang, M.

2010-12-01

In order to study the interior structure and geodynamic evolution of South China, we have started implementation of a linear seismic array observation in this region since December 2009. The linear array extends for ~2000 km from the northwestern continental interior all the way to the southeastern coastal area, across major tectonic units of South China including the Songpan-Ganze Orogenic Belt (SGOB) in the northwest, the Yangtze Craton (YzC) in the middle, and the Huanan Orogenic Belt (HOB) in the southeast. We plan to deploy a total of 200 broadband stations in the time period from December 2009 to June 2012. All the stations will be equipped with Guralp CMG-3ESP sensors and Ref-tek 130-1 or Ref-tek 72-A digitizers. The entire array observation includes three stages. In the time period from December 2009 to March 2011, 64 stations were deployed with a spatial interval of ~25 km from Chengdu city in Sichuan province in the west to Quanzhou city in Fujian province in the southeast of China. In the second stage, about 70 stations with a spatial interval of ~10 km will be deployed from Gonghe city in Qinghai province in the northwest to Chengdu city in the southeast in the time period from October 2010 to November 2011. In the last stage from April 2011 to June 2012, 66 stations with a spatial interval of ~25 km will be deployed to densify the station coverage along the Chengdu - Quanzhou segment of the profile. We have already analyzed the seismic data collected at the 64 stations using receiver function methods. Our preliminary results show an obvious W-E variation in the crustal thickness of the region. In particular, from inland to offshore of the Fujian Province the crustal thickness decreases, whereas the Poisson's ratio increases. These may indicate decreasing SiO2 and increasing calc-alkaline contents in the crust. The receiver function data also reveal a coherent structure of the 410-km and 660-km discontinuities along the observation profile

Energy audit data for a resort island in the South China Sea.

PubMed

Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2016-03-01

The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article "Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea" [1].

Energy audit data for a resort island in the South China Sea

PubMed Central

Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2015-01-01

The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article “Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea” [1]. PMID:26900590

Vietnam, the United States, and Japan in the South China Sea

DTIC Science & Technology

2014-10-01

Asia Pacific Center for Security Studies VIETNAM, THE UNITED STATES, AND JAPAN IN THE SOUTH CHINA SEA Dr. Alexander L. Vuving Paper for...since 1988. The standoff also served as a litmus test to identify who will side with whom in this conflict. While most of the world remained neutral...these actors relate to the South China Sea issue. This paper will focus on the three status quo powers; particularly, I will examine the strategies of

Seismic investigation of an ocean-continent transition zone in the northern South China Sea

NASA Astrophysics Data System (ADS)

Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

2011-12-01

Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

Sedimentary records of the Yangtze Block (South China) and their correlation with equivalent Neoproterozoic sequences on adjacent continents

NASA Astrophysics Data System (ADS)

Wang, Wei; Zhou, Mei-Fu

2012-07-01

The Neoproterozoic Danzhou Group, composed of siliciclastic sedimentary rocks interbedded with minor carbonate and volcanic rocks in the southeastern Yangtze Block, South China, is thought to be related to the breakup of Rodinia. Detrital zircon ages constrain the deposition of the Danzhou Group at ~ 770 Ma and ~ 730 Ma. The Danzhou Group contains dominant Neoproterozoic detrital zircon grains (~ 740-900 Ma) with two major age groups at ~ 740-790 Ma and ~ 810-830 Ma, suggesting the detritus was largely sourced from the widely distributed Neoproterozoic igneous plutons within the Yangtze Block. The sedimentary rocks from the lower Danzhou Group, including sandstones, siltstone and pelitic rocks, have UCC-like chemical signatures, representing mixed products of primary sources. The upper Danzhou Group received more recycled materials because the rocks have relatively higher Zr/Sc ratios, Hf contents and a greater influx of Pre-Neoproterozoic zircons. All of the rocks have high La/Sc, low Sc/Th and Co/Th ratios, consistent with sources dominantly composed of granitic to dioritic end-members from the western and northwestern Yangtze Block. Chemical compositions do not support significant contributions of mafic components. Most Neoproterozoic zircons have positive ɛHf(t) (0-17) indicative of sediments derived mainly from the western and northwestern Yangtze Block. The uni-modal Neoproterozoic zircons and felsic igneous source rocks for the Danzhou Group suggest that the Yangtze Block was an independent continent in the peripheral part of Rodinia.

Paleozoic–early Mesozoic gold deposits of the Xinjiang Autonomous Region, northwestern China

USGS Publications Warehouse

Rui, Zongyao; Goldfarb, Richard J.; Qiu, Yumin; Zhou, T.; Chen, R.; Pirajno, Franco; Yun, Grace

2002-01-01

The late Paleozoic–early Mesozoic tectonic evolution of Xinjiang Autonomous Region, northwestern China provided a favorable geological setting for the formation of lode gold deposits along the sutures between a number of the major Eastern Asia cratonic blocks. These sutures are now represented by the Altay Shan, Tian Shan, and Kunlun Shan ranges, with the former two separated by the Junggar basin and the latter two by the immense Tarim basin. In northernmost Xinjiang, final growth of the Altaid orogen, southward from the Angara craton, is now recorded in the remote mid- to late Paleozoic Altay Shan. Accreted Early to Middle Devonian oceanic rock sequences contain typically small, precious-metal bearing Fe–Cu–Zn VMS deposits (e.g. Ashele). Orogenic gold deposits are widespread along the major Irtysh (e.g. Duyolanasayi, Saidi, Taerde, Kabenbulake, Akexike, Shaerbulake) and Tuergen–Hongshanzui (e.g. Hongshanzui) fault systems, as well as in structurally displaced terrane slivers of the western Junggar (e.g. Hatu) and eastern Junggar areas. Geological and geochronological constraints indicate a generally Late Carboniferous to Early Permian episode of gold deposition, which was coeval with the final stages of Altaid magmatism and large-scale, right-lateral translation along older terrane-bounding faults. The Tian Shan, an exceptionally gold-rich mountain range to the west in the Central Asian republics, is only beginning to be recognized for its gold potential in Xinjiang. In this easternmost part to the range, northerly- and southerly-directed subduction/accretion of early to mid-Paleozoic and mid- to late Paleozoic oceanic terranes, respectively, to the Precambrian Yili block (central Tian Shan) was associated with 400 to 250 Ma arc magmatism and Carboniferous through Early Permian gold-forming hydrothermal events. The more significant resulting deposits in the terranes of the southern Tian Shan include the Sawayaerdun orogenic deposit along the Kyrgyzstan

Phylogenetic Analysis of Severe Fever with Thrombocytopenia Syndrome Virus in South Korea and Migratory Bird Routes Between China, South Korea, and Japan.

PubMed

Yun, Yeojun; Heo, Sang Taek; Kim, Gwanghun; Hewson, Roger; Kim, Hyemin; Park, Dahee; Cho, Nam-Hyuk; Oh, Won Sup; Ryu, Seong Yeol; Kwon, Ki Tae; Medlock, Jolyon M; Lee, Keun Hwa

2015-09-01

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral disease. The SFTS virus (SFTSV) has been detected in the Haemaphysalis longicornis, which acts as a transmission host between animals and humans. SFTSV was first confirmed in China in 2009 and has also been circulating in Japan and South Korea. However, it is not known if a genetic connection exists between the viruses in these regions and, if so, how SFTSV is transmitted across China, South Korea, and Japan. We therefore hypothesize that the SFTSV in South Korea share common phylogenetic origins with samples from China and Japan. Further, we postulate that migratory birds, well-known carriers of the tick H. longicornis, are a potential source of SFTSV transmission across countries. Our phylogenetic analysis results show that the SFTSV isolates in South Korea were similar to isolates from Japan and China. We connect this with previous work showing that SFTSV-infected H. longicornis were found in China, South Korea, and Japan. In addition, H. longicornis were found on migratory birds. The migratory bird routes and the distribution of H. longicornis are concurrent with the occurrence of SFTSV. Therefore, we suggest that migratory birds play an important role in dispersing H. longicornis-borne SFTSV. © The American Society of Tropical Medicine and Hygiene.

Exploring coral microbiome assemblages in the South China Sea.

PubMed

Cai, Lin; Tian, Ren-Mao; Zhou, Guowei; Tong, Haoya; Wong, Yue Him; Zhang, Weipeng; Chui, Apple Pui Yi; Xie, James Y; Qiu, Jian-Wen; Ang, Put O; Liu, Sheng; Huang, Hui; Qian, Pei-Yuan

2018-02-05

Coral reefs are significant ecosystems. The ecological success of coral reefs relies on not only coral-algal symbiosis but also coral-microbial partnership. However, microbiome assemblages in the South China Sea corals remain largely unexplored. Here, we compared the microbiome assemblages of reef-building corals Galaxea (G. fascicularis) and Montipora (M. venosa, M. peltiformis, M. monasteriata) collected from five different locations in the South China Sea using massively-parallel sequencing of 16S rRNA gene and multivariate analysis. The results indicated that microbiome assemblages for each coral species were unique regardless of location and were different from the corresponding seawater. Host type appeared to drive the coral microbiome assemblages rather than location and seawater. Network analysis was employed to explore coral microbiome co-occurrence patterns, which revealed 61 and 80 co-occurring microbial species assembling the Galaxea and Montipora microbiomes, respectively. Most of these co-occurring microbial species were commonly found in corals and were inferred to play potential roles in host nutrient metabolism; carbon, nitrogen, sulfur cycles; host detoxification; and climate change. These findings suggest that the co-occurring microbial species explored might be essential to maintain the critical coral-microbial partnership. The present study provides new insights into coral microbiome assemblages in the South China Sea.

Upper Miocene-Pliocene provenance evolution of the Central Canyon in northwestern South China Sea

NASA Astrophysics Data System (ADS)

Cui, Yuchi; Shao, Lei; Qiao, Peijun; Pei, Jianxiang; Zhang, Daojun; Tran, Huyen

2018-06-01

Provenance studies of the Central Canyon, Qiongdongnan Basin has provided significant insights into paleographic and sedimentology research of the South China Sea (SCS). A suite of geochemical approaches mainly including rare earth elemental (REE) analysis and detrital zircon U-Pb dating has been systematically applied to the "source-to-sink" system involving our upper Miocene-Pliocene Central Canyon sediments and surrounding potential source areas. Based on samples tracing the entire course of the Central Canyon, REE distribution patterns indicate that the western channel was generally characterized by positive Eu anomalies in larger proportion, in contrast to the dominance of negative values of its eastern side during late Miocene-Pliocene. Additionally, for the whole canyon and farther regions of Qiongdongnan Basin, the number of samples bearing negative Eu anomalies tended to increase within younger geological strata. On the other hand, U-Pb geochronology results suggest a wide Proterozoic to Mesozoic age range with peak complexity in Yanshanian, Indosinian, Caledonian and Jinningian periods. However in detail, age combination of most western samples displayed older-age signatures than the eastern. To make it more evidently, western boreholes of the Central Canyon are mainly characterized with confined Indosinian and Caledonian clusters which show great comparability with mafic-to-ultramafic source of Kontum Massif of Central Vietnam, while eastern samples largely bear with distinguishable Yanshanian and Indosinian peaks which more resemble with Hainan Island. Based on geochemistry and geochronology analyses, two significant suppliers and sedimentary infilling processes are generated: (1) the Indosinian collision orogenic belt in central-northern Vietnam, Indochina has ever played significant role in Central Canyon sedimentary evolution, (2) Hainan Island once as a typical provenance restricted within eastern Central Canyon, has been enlarging its influence

The South China sea margins: Implications for rifting contrasts

USGS Publications Warehouse

Hayes, D.E.; Nissen, S.S.

2005-01-01

Implications regarding spatially complex continental rifting, crustal extension, and the subsequent evolution to seafloor spreading are re-examined for the northern and southern-rifted margins of the South China Sea. Previous seismic studies have shown dramatic differences in the present-day crustal thicknesses as the manifestations of the strain experienced during the rifting of the margin of south China. Although the total crustal extension is presumed to be the same along the margin and adjacent ocean basin, the amount of continental crustal extension that occurred is much less along the east and central segments of the margin than along the western segment. This difference was accommodated by the early formation of oceanic crust (creating the present-day South China Sea basin) adjacent to the eastern margin segment while continued extension of continental crust was sustained to the west. Using the observed cross-sectional areas of extended continental crust derived from deep penetration seismics, two end-member models of varying rift zone widths and varying initial crustal thicknesses are qualitatively examined for three transects. Each model implies a time difference in the initiation of seafloor spreading inferred for different segments along the margin. The two models examined predict that the oceanic crust of the South China Sea basin toward the west did not begin forming until sometime between 6-12 my after its initial formation (???32 Ma) toward the east. These results are compatible with crustal age interpretations of marine magnetic anomalies. Assuming rifting symmetry with conjugate margin segments now residing along the southern portions of the South China Sea basin implies that the total width of the zone of rifting in the west was greater than in the east by about a factor of two. We suggest the most likely causes of the rifting differences were east-west variations in the rheology of the pre-rift crust and associated east-west variations in the

Isotopic and paleomagnetic constraints on the Mesozoic tectonic evolution of south China

NASA Astrophysics Data System (ADS)

Gilder, Stuart A.; Gill, James; Coe, Robert S.; Zhao, Xixi; Liu, Zhongwei; Wang, Genxian; Yuan, Kuirong; Liu, Wenlong; Kuang, Guodun; Wu, Haoruo

1996-07-01

In order to better constrain the paleogeographic evolution of south China we measured Sm-Nd and Rb-Sr isotopic compositions for 23 Mesozoic granites that crop out throughout the area. Tightly grouped neodymium depleted mantle model ages (1.4 ± 0.3 Ga) suggest the region is underlain by relatively homogeneous Proterozoic crust and fail to define crustal provinces. Neither the isotopic nor geologic data suggest that a Mesozoic suture exists. However, granites possessing anomalously high Sm (>8 ppm) and Nd (>45 ppm) concentrations, relatively high initial epsilon neodymium (-4 to -8), and high but variable initial 87Sr/86Sr (0.759 to 0.713) form a northeast trending zone that coincides with two prominent Mesozoic basins. Southeast of the zone lie the majority of Mesozoic intrusives and Upper Triassic to Lower Cretaceous extensional basins found in south China. Mesozoic paleomagnetic poles are well clustered northwest of the zone. Pre-Cretaceous poles southeast of it are discordant with respect to those from the northwest. The only recognized tectonostratigraphic terrane in south China lies southeast of the zone. The terrane is bordered by a northeast trending sinistral fault that was active in the Mesozoic. Other faults in south China have similar attitudes, ages, and sense of shear. Together, the observations suggest that the Mesozoic tectonic regime in south China consisted of strike-slip activity plus concomitant rifting as terranes or fragments of similar crust were transported north along sinistral faults. The zone, defined by the granites enriched in Nd and Sm, demarcates displaced terranes to the southeast from relatively stable land to the northwest.

Modeling Study of the Effect of Anthropogenic Aerosols on Late Spring Drought in South China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Ning; Liu, Xiaohong

2013-10-01

In this study, the mechanisms underlying the decadal variability of late spring precipitation in south China are investigated using the latest version 1 of Community Earth System Model (CESM1). We aim to unravel the effects of different climate forcing agents, such as aerosols and greenhouse gases (GHGs), on the decadal variation of precipitation with transient experiments from pre-industry (for year 1850) to present-day (for year 2000). Our results reveal that: (1) CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in south China; (2) Only simulations including the forcing of anthropogenic aerosols can reproducemore » the observed decreasing trend of late spring precipitation from 1950-2000 in south China; (3) Aerosols affect the decadal change of precipitation mainly by altering the large scale atmospheric circulation, and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and (4) In comparison, other climate forcing agents, such as GHGs, have much smaller effects on the decadal change of spring precipitation in south China. Key words: precipitation, aerosols, climate change, south China, Community Earth System Model« less

Authigenic carbonates from newly discovered active cold seeps on the northwestern slope of the South China Sea: Constraints on fluid sources, formation environments, and seepage dynamics

NASA Astrophysics Data System (ADS)

Liang, Qianyong; Hu, Yu; Feng, Dong; Peckmann, Jörn; Chen, Linying; Yang, Shengxiong; Liang, Jinqiang; Tao, Jun; Chen, Duofu

2017-06-01

Authigenic carbonates recovered from two newly discovered active cold seeps on the northwestern slope of the South China Sea have been studied using petrography, mineralogy, stable carbon and oxygen isotopic, as well as trace element compositions, together with AMS 14C ages of shells of seep-dwelling bivalves to unravel fluid sources, formation conditions, and seepage dynamics. The two seeps (ROV1 and ROV2), referred to as 'Haima seeps' herein, are approximately 7 kilometers apart, and are typified by abundant carbonate rocks represented bycrusts and nodules. Aragonite and high-Mg calcite are the main carbonate minerals. Based on low δ13Ccarbonate values ranging from -43.0‰ to -27.5‰ (V-PDB) methane is apparently the predominant carbon source of seep carbonates. The corresponding δ18O values, varying from 2.5‰ to 5.8‰ (V-PDB), mostly are higher than calculated values representing precipitation in equilibrium with seawater (2.5‰ to 3.8‰), which probably reflects past destabilization of locally abundant gas hydrates. In addition, we found that carbonates with bivalve shells are generally aragonite-dominated, and bear no barium enrichment but uranium enrichments, reflecting shallow formation depths close to the seafloor. In contrast, carbonate crusts without bivalve shells and nodules contain more calcite, and are characterized by major molybdenum enrichment and different degrees of barium enrichment, agreeing with precipitation at greater depth under strictly anoxic conditions. AMS 14C ages suggest that a major episode of carbonate precipitation occurred between 6.1 ka and 5.1 ka BP at the Haima seeps, followed by a possibly subordinate episode from approximately 3.9 ka to 2.9 ka BP. The common occurrence of dead bivalves at both sites indicates that chemosynthesis-based communities flourished to a greater extent in the past, probably reflecting a decline of seepage activity in recent times. Overall, these results confirm that authigenic carbonates from

The Pursuit of Economic Strength Has Stabilizing Effects in the South China Sea

DTIC Science & Technology

2016-09-01

but opposing schools of thought regarding the security environment and potential for armed conflict between states with competing territory and...South China Sea and the corresponding reactions by Southeast Asian nations, particularly Vietnam and the Philippines .3 By contrast, the liberal school ...whether Vietnam and the Philippines are trending toward conflict or cooperation in managing their competing South China Sea territory and resource

Circulation in the South China Sea during summer 2000 as obtained from observations and a generalized topography-following ocean model

NASA Astrophysics Data System (ADS)

Wang, Huiqun; Yuan, Yaochu; Guan, Weibing; Lou, Ruyun; Wang, Kangshan

2004-07-01

On the basis of the recently obtained hydrographic data in the South China Sea, the improved Princeton Ocean Model with a generalized topography-following coordinate system is used to study the circulation in the region during summer 2000. Several sensitivity experiments are carried out to achieve reasonable model parameters for the South China Sea (SCS). It is shown from the resting stratification experiments that the generalized topography-following coordinate scheme is better than the standard sigma grid scheme for reducing the pressure gradient errors. The combination of sea surface height anomaly derived from TOPEX/Poseidon and numerical results with both diagnostic and semidiagnostic simulations provides a consistent circulation pattern for the SCS in August, and the main circulation features can be summarized as follows: (1) There is a notable anticyclonic warm eddy southeast of Vietnam with a horizontal scale of ˜300 km, and there is a cyclonic cold eddy. The simultaneous existence of these cold and warm eddies is one of the important circulation characteristics in the SCS during summer 2000. (2) A secondary cold eddy is found east of Vietnam. (3) The northwestern part of the SCS is dominated by an anticyclonic circulation system. (4) There is also a secondary warm eddy southwest off the Luzon Island. (5) A cyclonic eddy is found west off the Borneo Island. (6) A western intensification phenomenon obviously occurs in the SCS. The dynamical mechanisms of the above-mentioned circulation pattern in the SCS are the interaction between the wind stress and bottom topography and the joint effect of baroclinicity and relief.

The Levels and Distribution of TN, TP and TOC in the South China Sea

NASA Astrophysics Data System (ADS)

Wang, H.; Han, D.

2012-04-01

The marine biogeochemistries of carbon, nitrogen and phosphorous have come under increased scrutiny because of their close involvement in climate change and coastal eutrophication. The South China Sea is unique in that located in a subtropical zone, and therefore represents an important regime for biogeochemical studies. However, to our knowledge, few data are available for total nitrogen (TN), total phosphorous (TP) and total organic carbon (TOC) in South Sea, China. The present study aims to contribute to the knowledge of their status through investigating the level and distribution of TN, TP and TOC in South China Sea. A total of 108 seawater samples of 11 sites in south sea, china were collected during August 29- September 4, 2006. An automated and simultaneous method for determination of TN and TOC was applied to all seawater samples. The combined system allowed simultaneous determination for TOC and TN in the same sample using a single injection and provided low detection limits and excellent linear ranges for both TOC and TN. The risk of contamination has been remarkably reduced due to the minimal sample manipulation and automated analyses. And quantitative analyses of TP in seawater were accomplished by a typical chemical method. Concentration ranges of TN and TP were 0.06-0.67, and 0.003-0.071 mg/L, respectively, as well as that of TOC were 0.23-2.51mg/L. The values of TN and TP showed that the status of nutrition is relatively better in south china sea than other marine areas. Moreover, the upright change trend of TN concentration level as well as TP and TOC according to the experimental results at the total 11 sites are simultaneity studied. The concentration of TN initial increases with the increasing of the depth, later the value becomes almost constant. In contrast, the concentration of TOC reduces with the increasing of the depth, later the value becomes almost unchangeable. Compared with the trend of TN and TOC, that of TP appears relatively stable

Dominant factors in controlling marine gas pools in South China

USGS Publications Warehouse

Xu, S.; Watney, W.L.

2007-01-01

In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up. ?? Higher Education Press and Springer-Verlag 2007.

Mummified fossil woods of Fagaceae from the upper Oligocene of Guangxi, South China

NASA Astrophysics Data System (ADS)

Huang, Luliang; Jin, Jianhua; Quan, Cheng; Oskolski, Alexei A.

2018-02-01

Three new fossil species, two attributed to the genus Castanopsis (C. nanningensis and C. guangxiensis) and one to the organ genus Lithocarpoxylon (L. nanningensis) are described on the basis of well-preserved mummified wood from the upper Oligocene of Yongning Formation in the Nanning Basin, Guangxi Province, South China. The two species of Castanopsis represent the most ancient reliable wood record of this genus in China and also southeastern Asia, which is the center of diversity of extant species. The fossil leaf records of Castanopsis indicated this genus has migrated to South China in the late Eocene. This fossil wood evidence confirms the presence and persistence of Castanopsis in this region in the late Oligocene. In the Yongning Formation, the presence of numerous Fagaceae woods with faint or absent growth ring boundaries (in C. nanningensis) occasionally associated with prominent ring-porous patterns, suggests that Guangxi (South China) had a seasonal (probably monsoonal) tropical climate during the late Oligocene.

Territorial disputes simmer in areas of South China Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-07-13

This paper reports that China's award of an exploration cooperation contact in the Nansha area of the South China Sea has revived territorial disputes in the area centering ton the Spratly and Paracel islands. The key dispute is between China and Viet Nam, which earlier engaged in military action over ownership of the islands, believed to have world class potential for hydrocarbon discoveries. Those two nations, as well as Brunei, Malaysia, Philippines, and Taiwan, lay claim to overlapping boundaries of the Spratly Islands. Separately, China and Viet Nam dispute territorial claims in the Paracels. Tensions continue to mount, and regionalmore » governments are trying to negotiate compromises to avoid a repeat of warfare.« less

Reviews and new metallogenic models of mineral deposits in South China: An introduction

NASA Astrophysics Data System (ADS)

Hu, Rui-Zhong; Chen, Wei Terry; Xu, De-Ru; Zhou, Mei-Fu

2017-04-01

In South China, the Yangtze and Cathaysia blocks were welded together along the Jiangnan Fold Belt during Neoproterozoic time (∼830 Ma). Large-scale mineralization in these two blocks occurred from Proterozoic to Cenozoic, making the region one of the most important polymetallic metallogenic provinces in the world. Of particular importance are world-class deposits of iron-oxide copper gold (IOCG), sediment-hosted Mn-P-Al-(Ni, Mo, PGE), syenite-carbonatite-related REE, felsic intrusion-related Sn-W-Mo-Cu-Fe-Pb-Zn, mafic intrusion-related V-Ti-Fe and Cu-Ni-PGE and low-temperature hydrothermal Pb, Zn, Au, and Sb (Fig. 1). In addition, the Ta-Nb, Hg, As, Tl and U deposits in South China are among the world largest of these kinds. Because of these deposits, South China has been a focus of researches for many years. Publications before 2005 were mostly restricted in Chinese. In the past decade, some case studies on some world-class deposits in South China are available in international journals. These recent studies have advanced our understanding of their mode of formation. However, some important issues regarding the timing, tectonic setting and mechanisms of metal concentration still remain poorly understood. This special issue brings together some of the latest information on these topics, including major review papers on specific types of mineralization and several papers dealing with some specific deposits in the region. We anticipate that this issue will generate more interests in the studies of mineral deposits in South China. In this introduction, we outline the tectonic framework and associated deposits.

Contemporary horizontal crustal movement estimation for northwestern Vietnam inferred from repeated GPS measurements

NASA Astrophysics Data System (ADS)

Duong, Nguyen Anh; Sagiya, Takeshi; Kimata, Fumiaki; To, Tran Dinh; Hai, Vy Quoc; Cong, Duong Chi; Binh, Nguyen Xuan; Xuyen, Nguyen Dinh

2013-12-01

We present a horizontal velocity field determined from a GPS network with 22 sites surveyed from 2001 to 2012 in northwestern Vietnam. The velocity is accurately estimated at each site by fitting a linear trend to each coordinate time series, after accounting for coseismic displacements caused by the 2004 Sumatra and the 2011 Tohoku earthquakes using static fault models. Considering the coseismic effects of the earthquakes, the motion of northwestern Vietnam is 34.3 ± 0.7 mm/yr at an azimuth of N108° ± 0.7°E in ITRF2008. This motion is close to, but slightly different from, that of the South China block. The area is in a transition zone between this block, the Sundaland block, and the Baoshan sub-block. At the local scale, a detailed estimation of the crustal deformation across major fault zones is geodetically revealed for the first time. We identify a locking depth of 15.3 ± 9.8 km with an accumulating left-lateral slip rate of 1.8 ± 0.3 mm/yr for the Dien Bien Phu fault, and a shallow locking depth with a right-lateral slip rate of 1.0 ± 0.6 mm/yr for the Son La and Da River faults.

Data from renewable energy assessments for resort islands in the South China Sea.

PubMed

Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2016-03-01

Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article "Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea" published in Energy (Khan et al., 2015) [1].

Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China.

PubMed

Yu, Ye; He, Jianjun; Zhao, Suping; Liu, Na; Chen, Jinbei; Mao, Hongjun; Wu, Lin

2016-11-01

Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou - a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in the

Euxinia prior to end-Permian main extinction at Xiaojiaba section, Sichuan Province, South China

NASA Astrophysics Data System (ADS)

Wei, H.; Algeo, T. J.; Chen, D.; Yu, H.

2013-12-01

Redox conditions in the global ocean prior to, during, and following the end-Permian mass extinction at 252.28 Ma remain contentious. Previous studies in western Australia, South China, and East Greenland have shown that photic-zone euxinia was present at least intermittently from the early Changhsingian through the Dienerian1-3. Here we report a study of organic carbon isotopes, pyrite sulfur isotopes, TOC, pyritic sulfur content, REE, and major and trace elements from the Upper Permian Xiaojiaba section in the Chaotian district of Guangyuan City, Sichuan Province, China. During the Permian-Triassic transition, this section was located on the northwestern margin of the South China Block, facing the Paleo-Tethys Ocean. Our results indicate that suboxic conditions prevailed during the Wuchiapingian and suboxic to anoxic conditions with several pulses of euxinia during the Changhsingian. δ13Corg values are mostly -28‰ to -26‰ but show three positive excursions (to -22‰) prior to the end-Permian mass extinction horizon. These positive excursions are associated with higher Spy concentrations (to ~1%). δ34Spy values are variable (from -41‰ to +5‰) but show a sharp negative excursion in the late Changhsingian (to -43.4‰) that coincided with the most positive δ13Corg values. This horizon is also associated with increases in Eu/Eu*, Baxs, ∑REE, Si, and redox-sensitive metals such as V. These patterns reflect linkage of the C and S cycles during the latest Permian, possibly in response to redox controls. The observed positive excursions in δ13Corg may be due to organic inputs from green sulfur bacteria, which exhibit a smaller photosynthetic fractionation (-12.5‰4) than eukaryotic algae. The pronounced negative excursion of δ34Spy corresponds to a sulfate-sulfide S isotope fractionation of about -60‰, suggesting a large flux of syngenetic framboidal pyrite, which would be indicative of euxinic water-column conditions. We infer that the euxinia prior

Source and Extent of Volcanic Ashes at the Permian-Triassic Boundary in South China and Its implications

NASA Astrophysics Data System (ADS)

Wang, M.; Zhong, Y. T.; Hou, Y. L.; He, B.

2017-12-01

Highly correlated with the Permian-Triassic Boundary (PTB) Mass Extinction in stratigraphic section, volcanic ashes around the P-T Boundary in South China have been suggested to be a likely cause of the PTB Mass Extinction. So the nature, source and extent of these volcanic ashes have great significance in figuring out the cause of the PTB Mass Extinction. In this study, we attempt to constrain the source and extent of the PTB volcanic ashes in South China by studying pyroclastic sedimentary rocks and the spatial distribution of tuffs and ashes in South China. The detrital zircons of tuffaceous sandstones from Penglaitan section yield an age spectrum peaked at 252Ma, with ɛHf(t) values varying from -20 to -5 ,and have Nb/Hf, Th/Nb and Hf/Th ratios similar to those from arc/orogenic-related settings. Coarse tuffaceous sandstones imply that their source is in limited distance. Those pyroclastic sedimentary rocks in Penglaitan are well correlated with the PTB volcanic ashes in Meishan GSSP section in stratigraphy. In the spatial distribution, pyroclastic sedimentary rocks and tuffs distribute only in southwest of South China, while finer volcanic ashes are mainly in the northern part. This spatial distribution suggests the source of tuffs and ashes was to the south or southwest of South China. Former studies especially that of Permian-Triassic magmatism in Hainan Island have supported the existence of a continental arc related to the subduction and closure of Palaeo-Tethys on the southwestern margin of South China during Permian to early Triassic. It is suggested that the PTB ashes possibly derived from this Paleo-Tethys continental arc. The fact that volcanic ashes haven't been reported or found in PTB stratum in North China or Northwest China implies a limited extent of the volcanism, which thus is too small to cause the PTB mass extinction.

Data from renewable energy assessments for resort islands in the South China Sea

PubMed Central

Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

2015-01-01

Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015) [1]. PMID:26779562

Seasonal variation and chemical characterization of PM2.5 in northwestern Philippines

NASA Astrophysics Data System (ADS)

Bagtasa, Gerry; Cayetano, Mylene G.; Yuan, Chung-Shin

2018-04-01

The seasonal and chemical characteristics of fine particulate matter (PM2.5) were investigated in Burgos, Ilocos Norte, located at the northwestern edge of the Philippines. Each 24 h sample of fine aerosol was collected for four seasons. Fine particulate in the region shows strong seasonal variation in both concentration and composition. Highest mass concentration was seen during the boreal spring season with a mean mass concentration of 21.6 ± 6.6 µg m-3, and lowest was in fall with a mean concentration of 8.4 ± 2.3 µg m-3. Three-day wind back trajectory analysis of air mass reveals the influence of the northwestern Pacific monsoon regimes on PM2.5 concentration. During southwest monsoon, sea salt was the dominant component of fine aerosols carried by moist air from the South China Sea. During northeast monsoon, on the other hand, both wind and receptor model analysis showed that higher particulate concentration was due to the long-range transport (LRT) of anthropogenic emissions from northern East Asia. Overall, sea salt and soil comprise 33 % of total PM2.5 concentration, while local biomass burning makes up 33 %. LRT of industrial emission, solid waste burning and secondary sulfate from East Asia have a mean contribution of 34 % to the total fine particulate for the whole sampling period.

An ensemble forecast of the South China Sea monsoon

NASA Astrophysics Data System (ADS)

Krishnamurti, T. N.; Tewari, Mukul; Bensman, Ed; Han, Wei; Zhang, Zhan; Lau, William K. M.

1999-05-01

This paper presents a generalized ensemble forecast procedure for the tropical latitudes. Here we propose an empirical orthogonal function-based procedure for the definition of a seven-member ensemble. The wind and the temperature fields are perturbed over the global tropics. Although the forecasts are made over the global belt with a high-resolution model, the emphasis of this study is on a South China Sea monsoon. Over this domain of the South China Sea includes the passage of a Tropical Storm, Gary, that moved eastwards north of the Philippines. The ensemble forecast handled the precipitation of this storm reasonably well. A global model at the resolution Triangular Truncation 126 waves is used to carry out these seven forecasts. The evaluation of the ensemble of forecasts is carried out via standard root mean square errors of the precipitation and the wind fields. The ensemble average is shown to have a higher skill compared to a control experiment, which was a first analysis based on operational data sets over both the global tropical and South China Sea domain. All of these experiments were subjected to physical initialization which provides a spin-up of the model rain close to that obtained from satellite and gauge-based estimates. The results furthermore show that inherently much higher skill resides in the forecast precipitation fields if they are averaged over area elements of the order of 4° latitude by 4° longitude squares.

The nexus of oil consumption, CO2 emissions and economic growth in China, Japan and South Korea.

PubMed

Saboori, Behnaz; Rasoulinezhad, Ehsan; Sung, Jinsok

2017-03-01

This article attempts to explore the nexus between oil consumption, economic growth and carbon dioxide (CO 2 ) emissions in three East Asian oil importing countries (i.e. China, South Korea and Japan) over the period 1980-2013, by using the Granger causality, Johansen cointegration test, Generalised Impulse Response functions (GIRF) and variance decompositions. The empirical findings provide evidence for the existence of a long-run relationship between oil consumption and economic growth in China and Japan. The results also point to a uni-directional causality from running from oil consumption to economic growth in China and Japan, and from oil consumption to CO 2 emissions in South Korea. The overall results of GIRF reveal that while economic growth in China and South Korea shows a positive response to oil consumption, this variable responses negatively to the same shock in Japan. In addition, oil consumption spikes cause a negative response of CO 2 emissions in Japan and China, as well as a U-shape response in South Korea.

Is extreme climate or moderate climate more conducive to longevity in China?

NASA Astrophysics Data System (ADS)

Huang, Yi; Rosenberg, Mark; Wang, Yingli

2018-02-01

Climate is closely related to human longevity. In China, there are many climate types. According to national population censuses from 1982 to 2000, most provinces with a high ratio of centenarians are located in western and northwestern China far from the sea; these areas are characterized by a dry, cold climate, very high altitude, very high daily temperature range, strong winds, and partial hypoxia. Meanwhile, provinces with a high ratio of nonagenarians from 1982 to 2000 are located in southern China near the sea. Previous studies have attributed the high ratio of centenarians in western and northwestern China to the extreme local climate. However, centenarians in these areas decreased greatly in 2010, whereas residents in southern China frequently reached 90 to 100 years old in 2010. This study aims to explain this strange phenomenon and find whether extreme climate in Tibetan plateau and northwestern China or moderate climate in southern China is more conducive to longevity. The study found that mortality rate in Tibetan plateau is much higher than southern China, then a population evolution experiment was proposed to compare longevity indicators between low mortality rate and high mortality rate and shows that longevity indicators will decrease in the near future and increase above their original levels after several decades when the mortality rate is decreased. Results of this study show individuals in northwestern China do not live as long as those in eastern and southern China. A moderate climate is more conducive to longevity than extreme climate in China. The longevity of a region should be judged by long-term longevity indicators.

Is extreme climate or moderate climate more conducive to longevity in China?

NASA Astrophysics Data System (ADS)

Huang, Yi; Rosenberg, Mark; Wang, Yingli

2018-06-01

Climate is closely related to human longevity. In China, there are many climate types. According to national population censuses from 1982 to 2000, most provinces with a high ratio of centenarians are located in western and northwestern China far from the sea; these areas are characterized by a dry, cold climate, very high altitude, very high daily temperature range, strong winds, and partial hypoxia. Meanwhile, provinces with a high ratio of nonagenarians from 1982 to 2000 are located in southern China near the sea. Previous studies have attributed the high ratio of centenarians in western and northwestern China to the extreme local climate. However, centenarians in these areas decreased greatly in 2010, whereas residents in southern China frequently reached 90 to 100 years old in 2010. This study aims to explain this strange phenomenon and find whether extreme climate in Tibetan plateau and northwestern China or moderate climate in southern China is more conducive to longevity. The study found that mortality rate in Tibetan plateau is much higher than southern China, then a population evolution experiment was proposed to compare longevity indicators between low mortality rate and high mortality rate and shows that longevity indicators will decrease in the near future and increase above their original levels after several decades when the mortality rate is decreased. Results of this study show individuals in northwestern China do not live as long as those in eastern and southern China. A moderate climate is more conducive to longevity than extreme climate in China. The longevity of a region should be judged by long-term longevity indicators.

Comparison of modern pollen distribution between the northern and southern parts of the South China Sea.

PubMed

Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

2015-04-01

The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

Crustal and Upper Mantle Velocity Structure beneath Northwestern South America revealed by the CARMArray

NASA Astrophysics Data System (ADS)

Miao, W.; Cornthwaite, J.; Levander, A.; Niu, F.; Schmitz, M.; Dionicio, V.; Nader-Nieto, M. F.

2017-12-01

The Caribbean plate (CAR) is a fragment of the Farallon plate heavily modified by igneous processes that created the Caribbean large igneous province (CLIP) between 110 and 80 Ma.The CAR collided with and initiated subduction beneath northwestern South America plate (SA) at about 60-55 Ma as a narrow flat-slab subduction zone with an accretionary prism offshore, but no volcanic arc. Large scale regional tomography suggests that 1000 km of the CAR has been subducted (Van Benthem et al., 2013, JGR). The flat slab has caused Laramide-style basement uplifts of the Merida Andes, Sierra de la Perija, and Santa Marta ranges with elevations >5 km. The details of subduction geometry of the CAR plate beneath northeastern Colombia and northwestern Venezuela are complicated and remain unclear. The region of slab steepening lies below the triangular Maracaibo block (Bezada et al, 2010, JGR), bounded by major strike slip faults and currently escaping to the north over the CAR. Geodetic data suggests the this region has the potential for a magnitude 8+ earthquake (Bilham and Mencin, 2013, AGU Abstract). To better understand the subduction geometry, we deployed 65 broadband (BB) stations across northeastern Colombia and northwestern Venezuela in April of 2016. The 65 stations interweave with the 32 existing Colombian and Venezuelan BB stations, forming a 2-D array (hereafter referred to as CARMArray) with a station spacing of 35-100 km that covers an area of 600 km by 400 km extending from the Caribbean coast in Colombia to the interior plains of Venezuela. With data from the first year of operation, we have measured the Rayleigh wave phase velocities and Z/H ratios in the period range of 8-40 s using both ambient noise and earthquake data recorded by the CARMArray. We also generated Ps receiver functions from waveform data of teleseismic events recorded by the array. We then jointly inverted the three datasets to construct a 3-D S-wave velocity model beneath the array. We will

Properties of black carbon and other insoluble light-absorbing particles in seasonal snow of northwestern China

NASA Astrophysics Data System (ADS)

Pu, Wei; Wang, Xin; Wei, Hailun; Zhou, Yue; Shi, Jinsen; Hu, Zhiyuan; Jin, Hongchun; Chen, Quanliang

2017-05-01

A large field campaign was conducted and 284 snow samples were collected at 38 sites in Xinjiang Province and 6 sites in Qinghai Province across northwestern China from January to February 2012. A spectrophotometer combined with chemical analysis was used to measure the insoluble light-absorbing particles (ILAPs) and chemical components in seasonal snow. The results indicate that the cleanest snow was found in northeastern Xinjiang along the border of China, and it presented an estimated black carbon (CBCest) of approximately 5 ng g-1. The dirtiest snow presented a CBCest of approximately 450 ng g-1 near industrial cities in Xinjiang. Overall, the CBCest of most of the snow samples collected in this campaign was in the range of 10-150 ng g-1. Vertical variations in the snowpack ILAPs indicated a probable shift in emission sources with the progression of winter. An analysis of the fractional contributions to absorption implied that organic carbon (OC) dominated the 450 nm absorption in Qinghai, while the contributions from BC and OC were comparable in Xinjiang. Finally, a positive matrix factorization (PMF) model was run to explore the sources of particulate light absorption, and the results indicated an optimal three-factor/source solution that included industrial pollution, biomass burning, and soil dust.

Effect of a fast-moving tropical storm Washi on phytoplankton in the northwestern South China Sea

NASA Astrophysics Data System (ADS)

Zhao, Hui; Pan, Jiayi; Han, Guoqi; Devlin, Adam T.; Zhang, Shuwen; Hou, Yijun

2017-04-01

Tropical cyclones may augment nutrients in the ocean surface layer through mixing, entrainment, and upwelling, triggering phytoplankton blooms in oligotrophic waters such as the South China Sea (SCS). Previous studies focused mainly on responses of marine environments to strong or slow-moving typhoons in the SCS. In this study, we analyze variations of chlorophyll a (Chl a) and oceanic conditions in the continental shelf region east of Hainan Island during the fast-moving tropical storm Washi and investigate its influences on phytoplankton bloom and related dynamic mechanisms. Results indicate that there was significant variation of Chl a concentration in the continental shelf region, with low values (about 0.1 mg m-3) before the storm and a 30% increase after the storm. This increase was spatially variable, much larger nearshore than offshore. Power spectral analysis of Acoustic Doppler Current Profiler (ADCP) data at a shelf site near the study region reveals strong near-inertial oscillations (NIOs) in the upper layer, with a period of about 36 h, close to the local inertial period. The NIOs intensified mixing and modified the stratification of the upper layer, inducing uplift of nutrients and Chl a into the mixed layer from below, and leading to surface Chl a increase. The relatively shallow nutricline and thermocline in the continental shelf region before the storm were favorable for upwelling of nutrients and generation of NIOs. Advection of nutrients from enhanced runoff during and after the storm may be responsible for the larger increase of the Chl a nearshore.

Landfalling characteristics of the tropical cyclones generated in the South China Sea

NASA Astrophysics Data System (ADS)

Yang, L.; Wang, D.

2012-12-01

Tracks of tropical cyclones (TCs) in the South China Sea (SCS) during 1970-2010 can mainly be divided into two categories: Westward (including west and northwest) and Eastward (east and northeast). TCs moving westward tend to make landfall along the South china or Vietnam coast, while those moving eastward tend to dissipate in the ocean or make landfall on Taiwan, Philippine Islands or occasionally the South China coast. During spring (April-May), there are 17 TCs generated in the SCS, among which 13 moves eastward, but only 4 moves westward. A total of 95 TCs forms in the SCS during TC peak season (June-September), among which 71 TCs move westward, about three times more than that moving eastward (24). During October-December, 33 TCs move westward and 12 eastward. The variability of TC track direction is investigated on intraseasonal, seasonal and inter-annual scale circulation. It is found that TC landfall activities are related to Madden-Julian Oscillation (MJO), El Nino-Southern Oscillation (ENSO), monsoon activities and TC genesis locations.

Mesozoic Deformation and Its Geological Significance in the Southern Margin of the South China Sea

NASA Astrophysics Data System (ADS)

Zhu, Rongwei; Liu, Hailing; Yao, Yongjian; Wang, Yin

2018-05-01

The pre-Eocene history of the region around the present South China Sea is not well known. New multi-channel seismic profiles provide valuable insights into the probable Mesozoic history of this region. Detailed structural and stratigraphic interpretations of the multi-channel seismic profiles, calibrated with relevant drilling and dredging data, show major Mesozoic structural features. A structural restoration was done to remove the Cenozoic tectonic influence and calculate the Mesozoic tectonic compression ratios. The results indicate that two groups of compressive stress with diametrically opposite orientations, S(S)E-N(N)W and N(N)W-S(S)E, were active during the Mesozoic. The compression ratio values gradually decrease from north to south and from west to east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate at which the Nansha block drifted northward in the late Jurassic to late Cretaceous. The Nansha block drifted northward until it collided and sutured with the southern China margin. The opening of the present South China Sea may be related to this suture zone, which was a tectonic zone of weakness.

Pooled versus separate tree-ring δD measurements, and implications for reconstruction of the Arctic Oscillation in northwestern China.

PubMed

Liu, Xiaohong; An, Wenling; Treydte, Kerstin; Wang, Wenzhi; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Wang, Bo; Zhang, Xuanwen

2015-04-01

Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ18O or δ13C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce (Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical Composition of Sea Fog Water Along the South China Sea

NASA Astrophysics Data System (ADS)

Yue, Yanyu; Niu, Shengjie; Zhao, Lijuan; Zhang, Yu; Xu, Feng

2012-12-01

The chemical and microphysical properties of sea fog were measured during a field experiment on Donghai Island, Zhanjiang of China from March 15 to April 18, 2010. The average pH and electrical conductivity (EC) value of the six sea fog cases during the experiment was 5.2 and 1,884 μS/cm. The observed total ion concentration of sea fog was four orders of magnitude higher than those in the North Pacific and other sea areas of China. The dominant anion and cation in all sea fog water samples were Cl- and Na+, respectively. From backward trajectory analysis and ion loading computation, it can be concluded that the ions in the samples were transported either from pollutants in distant industrial cities or from local ion deposition processes. The concentration of Ca2+ in the sea fog water samples in Case 2 suggested that a dust storm in the Inner Mongolia, a northern region of China several thousand kilometers away, could reach the South China Sea. The data also showed that the sea fog droplet spectrum over the South China Sea is unimodal. Through relationship analysis, it is illustrated that the evolution of microphysics (such as droplet concentration, diameter, and liquid water content) during fog process could affect the chemical properties of sea fog.

Malaysia’s Great Power Balance and the South China Sea Disputes

DTIC Science & Technology

2013-03-01

Word Count: 7074 14. ABSTRACT Malaysia is one of several Southeast Asian countries that claim a portion of the South China Sea that is also claimed...by China. However, Malaysia has chosen to downplay this dispute in the interest of furthering positive relations with China, in particular...economically. In recent years Malaysia has also improved its political and military relations with the U.S.; the two countries have long enjoyed strong

Perceived resource support for chronic illnesses among diabetics in north-western China.

PubMed

Zhong, Huiqin; Shao, Ya; Fan, Ling; Zhong, Tangshen; Ren, Lu; Wang, Yan

2016-06-01

A high level of social support can improve long-term diabetes self-management. Support from a single source has been evaluated. This study aims to analyze support from multiple and multilevel sources for diabetic patients by using the Chronic Illness Resources Survey (CIRS). Factors influencing the utilization of the CIRS were also evaluated. A total of 297 patients with diabetes were investigated using the CIRS and Perceived Diabetes Self-management Scale in Shihezi City, China. Descriptive statistics were used to explain demographic variables and scores of the scales. Factors affecting the utilization of chronic illness resources were determined through univariate analysis and then examined by multivariate logistic regression analysis. Of the 297 diabetic patients surveyed, 67% failed to reach the standard (more than 3 points) of utilizing chronic illness resources. Moreover, utilization of chronic illness resources was positively moderately correlated with self-management of diabetes (r = 0.75, P < 0.05). According to the multivariate logistic regression analysis, age (OR, 3.42; 95%CI, 1.19-9.84) and monthly income (OR, 5.27; 95%CI, 1.86-14.90) were significantly positively associated with the CIRS score. Individuals with high school (OR, 2.61; 95%CI, 1.13-6.05) and college (OR, 3.02; 95%CI, 1.13-8.04) degrees obtained higher scores in the survey than those with elementary school education. Results indicated that utilization of resources and support for chronic illness self-management, particularly personal adjustment and organization, were not ideal among diabetics in the communities of north-western China. Improved utilization of chronic illness resources was conducive for proper diabetes self-management. Furthermore, the level of utilization of chronic illness resources increased with age, literacy level, and monthly income.

Three Disputes and Three Objectives: China and the South China Sea

DTIC Science & Technology

2011-01-01

the King of Italy on the Subject of the Difference Relative to the Sovereignty over Clipperton Island (France v. Mexico), January 28, 1931,” in...territorial sover- eignty, in the overlapping claims to the South China Sea’s islands , rocks, and reefs; disputes over which coastal states claim rightful...of Vietnam in the Paracel Islands in 1974, China’s attack on Vietnamese forces near Fiery Cross Reef in 1988, and China’s military ouster of

Sequence Analysis of Mitochondrial Genome of Toxascaris leonina from a South China Tiger.

PubMed

Li, Kangxin; Yang, Fang; Abdullahi, A Y; Song, Meiran; Shi, Xianli; Wang, Minwei; Fu, Yeqi; Pan, Weida; Shan, Fang; Chen, Wu; Li, Guoqing

2016-12-01

Toxascaris leonina is a common parasitic nematode of wild mammals and has significant impacts on the protection of rare wild animals. To analyze population genetic characteristics of T. leonina from South China tiger, its mitochondrial (mt) genome was sequenced. Its complete circular mt genome was 14,277 bp in length, including 12 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 non-coding regions. The nucleotide composition was biased toward A and T. The most common start codon and stop codon were TTG and TAG, and 4 genes ended with an incomplete stop codon. There were 13 intergenic regions ranging 1 to 10 bp in size. Phylogenetically, T. leonina from a South China tiger was close to canine T. leonina . This study reports for the first time a complete mt genome sequence of T. leonina from the South China tiger, and provides a scientific basis for studying the genetic diversity of nematodes between different hosts.

[Aluminum mobilization models of forest yellow earth in South China].

PubMed

Xin, Yan; Zhao, Yu; Duan, Lei

2009-07-15

For the application of acidification models in predicting effects of acid deposition and formulating control strategy in China, it is important selecting regionally applicable models of soil aluminum mobilization and determining their parameters. Based on the long-term monitoring results of soil water chemistry from four forested watersheds in South China, the applicability of a range of equilibriums describing aluminum mobilization was evaluated. The tested equilibriums included those for gibbsite, jurbanite, kaolinite, imogolite, and SOM-Al: Results show that the gibbsite equilibrium commonly used in several acidification models is not suitable for the typical forest soil in South China, while the modified empirical gibbsite equation is applicable with pK = - 2.40, a = 1.65 (for upper layer) and pK = - 2.82, a = 1.66 (for lower layers) at only pH > or = 4. Comparing with the empirical gibbsite equation, the other equilibriums do not perform better. It can also be seen that pAl varies slightly with pH decreases at pH < 4, which is unexplainable by any of these suggested equilibriums.

Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

NASA Astrophysics Data System (ADS)

Tang, Y.

2009-12-01

Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

O3, SO2, NO2, and UVB measurements in Beijing and Baseline Station of northwestern part of China

NASA Technical Reports Server (NTRS)

Guo, Song; Zhou, Xiuji; Zhang, Xiachun

1994-01-01

A MKII Brewer ozone spectrometer was used in Beijing from Oct. 1990 to June 1991 to measure O3, SO2 and UVB radiation. And since Nov. 1991 a new MKIV Brewer spectrometer, which can take the measurements of O3, SO2, NO2 and UVB radiation, has been set up in Beijing. The MKII Brewer spectrometer was moved to Qinghai baseline station which is on the Qinghai-tibetean plateau in the northwestern part of China. Both the data in Beijing and Qinghai baseline station has been analyzed and some results will be shown here along with the ozone profiles botained through the Umkehr program given by AES of Canada for the Brewer ozone spectrometer.

Essential medicines lists for children of WHO, India, South Africa, and EML of China: A comparative study.

PubMed

Liu, Dan; Cheng, Jing; Zhang, Ling-Li; Li, You-Ping; Zeng, Li-Nan; Zhang, Chuan; Gui, Ge

2017-11-01

Comparing the essential medicine lists for children and China national essential medicine list 2012, to provide the evidence for establishing essential medicine list for children in China. Search the official websites of WHO and some other countries' ministry of health to get essential medicine lists for children (EMLc) that have already established. Compare the situation of updating, the number and classification of medicines, and the dosage forms in essential medicine lists for children and China national essential medicine list 2012. By December 2013, the WHO, India, and South Africa have established EMLc. The list of China was for people in all ages, so the number of medicines ranked first in four lists. WHO, India, and China classified the medicines by pharmacologic action, South Africa classified by ATC classification. Except for WHO, India, South Africa, and China did not have specific medicines for neonatal care or medicines for diseases of joints. The main administration routes in these four lists were oral administration, injection, and topical application. There were medicine restrictions in lists of WHO and India, but there were no medicine restrictions in the lists of South Africa and China. Compared with EMLs for children, the 2012 National Essential Medicine List for China is not suitable for children in China. Development of Chinese EMLc should be based on the burden of diseases for children, and should select applicable dosage forms and specifications. © 2016 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

Antecedents of Medical Workplace Violence in South China

ERIC Educational Resources Information Center

Cai, Wenzhi; Deng, Ling; Liu, Meng; Yu, Min

2011-01-01

It has been noted that workplace violence most frequently occurs in hospitals. The purpose of this study was to explore antecedents of workplace violence in south China. The authors conducted face-to-face, in-depth, semistructured interviews with 30 hospital staff who had experienced at least one incident of workplace violence from patients during…

The origin of groundwater in Zhangye Basin, northwestern China, using isotopic signature

NASA Astrophysics Data System (ADS)

Chen, Jiansheng; Liu, Xiaoyan; Sun, Xiaoxu; Su, Zhiguo; Yong, Bin

2014-03-01

Zhangye Basin, in arid northwestern China, has recently been repeatedly flooded by rising groundwater. Isotope signatures of sampled waters gained insight into the recharge source of the groundwater. The summer Heihe River water and most of the spring water in Zhangye and Yongchang basins plotted above the global meteoric water line (GMWL) on the δ18O-δD plot. The spring water had R/Ra ratio >1, low TDS and high tritium, which indicates origin from Qilian Mountain glacier meltwater. The groundwater of Qilian Mountains was transported to the Hexi Corridor (in which Zhangye Basin is located) through underground fault zones. Additionally, some of the groundwater in the alluvial plain, and all spring water surrounding Zhangye Basin, plotted below the GMWL on the δ18O-δD plot along an evaporation line, and had R/Ra ratio < 1 and high TDS. It is proposed that the Tibetan rivers or lakes source the Hexi Corridor groundwater through either the NE-trending or NW-trending buried fault zones. The isotopic signatures presented as part of this study rule out the conventional viewpoint that groundwater of the Zhangye Basin was recharged by local precipitation and infiltration of Heihe River water on the alluvial plain.

CAN INTERNATIONAL LAW MAKE A DIFFERENCE UNCLOS AND THE SOUTH CHINA SEA

DTIC Science & Technology

2017-03-20

insignificant to a country that is hedging its bets and its control to become a regional power house. 15 Unfortunately for China, the PCA’s decision...published by China’s think tank, the National Institute for South China Sea Studies, that warns the US that its freedom of navigation patrols in the...Bloomberg, “US Naval Patrols Threaten Sovereignty, China Think Tank Warns,” Stars and Stripes 25 November 2016 https://www.stripes.com/news

Is extreme climate or moderate climate more conducive to longevity in China?

PubMed

Huang, Yi; Rosenberg, Mark; Wang, Yingli

2018-06-01

Climate is closely related to human longevity. In China, there are many climate types. According to national population censuses from 1982 to 2000, most provinces with a high ratio of centenarians are located in western and northwestern China far from the sea; these areas are characterized by a dry, cold climate, very high altitude, very high daily temperature range, strong winds, and partial hypoxia. Meanwhile, provinces with a high ratio of nonagenarians from 1982 to 2000 are located in southern China near the sea. Previous studies have attributed the high ratio of centenarians in western and northwestern China to the extreme local climate. However, centenarians in these areas decreased greatly in 2010, whereas residents in southern China frequently reached 90 to 100 years old in 2010. This study aims to explain this strange phenomenon and find whether extreme climate in Tibetan plateau and northwestern China or moderate climate in southern China is more conducive to longevity. The study found that mortality rate in Tibetan plateau is much higher than southern China, then a population evolution experiment was proposed to compare longevity indicators between low mortality rate and high mortality rate and shows that longevity indicators will decrease in the near future and increase above their original levels after several decades when the mortality rate is decreased. Results of this study show individuals in northwestern China do not live as long as those in eastern and southern China. A moderate climate is more conducive to longevity than extreme climate in China. The longevity of a region should be judged by long-term longevity indicators.

High Resolution Biostratigraphy and the Origin of the Basal Cambrian Bedded Chert from the Aksu Area (Tarim Block, Northwestern China)

NASA Astrophysics Data System (ADS)

Wang, Z.; Liu, H.; Dong, L.

2017-12-01

The early Cambrian Yurtus Formation in the Aksu area (Tarim block, northwestern China) consists of two lithostratigraphic units, lower black shale with interbedded chert unit and upper siltstone/carbonate unit. This time period represents the most important Proterozoic- Phanerozoic transition in earth's history. In recent years, the black shale has been confirmed to have high hydrocarbon generation potential. However, the depositional environment of the Yurtus Formation remains controversial and the biostratigraphic constrains are rather poor. The chert that is interbedded with black shale in the Yurtus Formation provides an exceptional taphonomic window to capture the diversity of the early Cambrian microfossils. Meanwhile, the origin of the bedded chert would give us some insight into the environmental background when the source rock was deposited. Therefore, in this research, we focus on the chert in the lower Yurtus formation and our purpose is to establish high resolution biostratigraphic framework and to better understand the depositional environment of the source rock. We investigated 4 sections in the Tarim basin: Kungaikuotan, Sugaite, Kule, and Yurtus VI. Abundant acritarch fossils have been identified, including Heliosphaeridium ampliatum, Yurtusia uniformis, and Comasphaeridium annulare. The tubular fossil Megathrix longus is also very common in this formation. In addition, two new types of specimens have been discovered, sheet-like encrolled fossils ( 0.5 mm in size) and regular spindle-like double layered microfossils ( 10μm in diameter). All of these fossils have constant occurrences in the studied sections, and can be well correlated with those yielded from the equivalent interval in South China. The biostratigraphic work suggests the source rock in the lower unit of the Yurtus Formation could be correlated with the Meishucunian small shelly fossil assemblage I and II. The Gemenium/Silicon ratio of the Yurtus chert is less than 1�

Composition and genesis of ferromanganese deposits from the northern South China Sea

NASA Astrophysics Data System (ADS)

Zhong, Yi; Chen, Zhong; González, Francisco Javier; Hein, James R.; Zheng, Xufeng; Li, Gang; Luo, Yun; Mo, Aibin; Tian, Yuhang; Wang, Shuhong

2017-05-01

Marine ferromanganese (Fe-Mn) nodules and crusts are archives of past environmental conditions and potential mineral resources. Over the last 30 years, many have been discovered in the northern South China Sea (SCS). To determine the origin of the Fe-Mn deposits, a comprehensive laboratory analysis of physical properties, mineralogy and geochemistry was conducted on newly collected Fe-Mn nodule/crust samples. The results revealed that there are three types of Fe-Mn deposits: (1) Fe-rich nodules containing essentially goethite occur on the northeastern slope of the SCS, with high Fe, low Mn (Mn/Fe = 0.03) and low trace metals and rare earth elements concentrations; (2) Smooth Fe-Mn nodules and crusts composed of asbolane, todorokite and CFA occur along the northwestern marginal of the SCS that have similar Fe and Mn contents (Mn/Fe = 1.21), moderate trace metal enrichments, and a positive Ce anomaly; (3) Fe-Mn nodules and crusts composed of asbolane, todorokite and birnessite that occur in the central basin of the SCS have higher Mn and lower Fe contents (Mn/Fe = 1.45). This depositional pattern was associated with major changes in oceanographic conditions and tectonic regimes. The northeastern slope deposits occur in a contourite depositional system, are strongly enriched in Fe relative to Mn (average 38.7% and 0.96%, respectively), formed from the combination of hydrogenetic and diagenetic processes. We propose a new genetic model for Fe-Mn nodules, which formed through the oxidation of pyrite and pyrite-barite concretions that formed by rapid early diagenetic growth (average 3320 mm/Myr) on continental margins above the carbonate compensation depth, and dominated by hydrocarbon seep structures and strong erosive action of bottom currents along the northeastern slope. In contrast, the introduction of vigorous deep-water flow from the North Pacific promoted the slow growth (4-7 mm/Myr) of hydrogenetic Fe-Mn nodules and crusts along the northwestern margin. Finally

Origin of heavy rare earth mineralization in South China

PubMed Central

Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

2017-01-01

Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (ɛNd(t)=0.9±0.8 versus −11.5±0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource. PMID:28220784

Finite-Frequency Seismic Imaging of Upper-Mantle Velocity Structures Beneath the South China Continent

NASA Astrophysics Data System (ADS)

Qu, P.; Chen, Y. J.; Yu, Y.

2017-12-01

South China Continent is major formed from the Paleo-South China plate. The continent has experienced complicated tectonic history after Neoproterozoic. Previous studies suggested some possible model for the collision between South China Continent and North China Continent. Body wave tomography and surface wave tomography are widely used to inverse upper mantle velocity structure. In our study, finite frequency tomography were carried on to get explanation more correctly. We gathered nearly 60000 pieces of teleseismic event records by 166 broad band seismic stations with Mw > 5.5. Here sensitive kernel of ak135 velocity structure was calculated, which is based on Born approximation, and then we applied multi-channel cross-correlation to pick arrival time difference under 3 frequency band. Combining with crust thickness correct from receiver function, we solve the inversion matrix by LSQR method, and get accurate upper mantle structure of P, S velocity. For more accurate results, we apply a method to calculate Vp/Vs ratio, to help to verify the velocity anomaly. The result in this research shows: 1. A strong velocity anomaly exists in the northern of South China Continent, in an area 31°N between 112°-118°E. The anomaly is about . We suggest that, this anomaly is related to the collision from North China Continent. It implies the collision underthrusted to southward. 2. A clearly slow velocity anomaly exists in the northern of Cathaysia block. This low velocity anomaly exist on the boundary of Yangtz block and Cathysian block, it is related to the left over of block collision in early phanerozoic. 3. We recognized some little velocity anomaly exit in the research area. Comparing these velocity anomaly with U-Pb zircon ages, we suggest complicated orogenesis in Phanerozoic is the cause of the formation of these little anomaly. The result in our study support the collision model, which shows the underthrust direction is southward, on the south of Qinling

South China Sea summer monsoon onset in relation to the off-equatorial ITCZ

NASA Astrophysics Data System (ADS)

Zhou, Wen; Chan, Johnny Chung-Leung; Li, Chongyin

2005-09-01

Observations of the South China Sea summer monsoon (SCSSM) demonstrate the different features between the early and late onsets of the monsoon. The determining factor related to the onset and the resultant monsoon rainfall might be the off-equatorial ITCZ besides the land-sea thermal contrast. The northward-propagating cumulus convection over the northern Indian Ocean could enhance the monsoon trough so that the effect of the horizontal advection of moisture and heat is substantially increased, thus westerlies can eventually penetrate and prevail over the South China Sea (SCS) region.

Identification of multiple magnetizations of the Ediacaran strata in South China

NASA Astrophysics Data System (ADS)

Jing, Xianqing; Yang, Zhenyu; Tong, Yabo; Wang, Heng; Xu, Yingchao

2018-01-01

A suspected Silurian remagnetization of the Ediacaran strata of South China was proposed decades ago by many researchers, but, there has been no systematic study of its causes and mechanisms. In this study, we investigate the multiphase remagnetization processes that affected the Ediacaran strata and the possible mechanisms of these remagnetization events. We conducted detailed palaeomagnetic, rock magnetic and scanning electron microscope (SEM) studies of samples from the Ediacaran strata in the Jiulongwan (JLWE, JLWS), Qinglinkou (QLK) and Sanxiarenjia (SXRJ) sections in the Three Gorges Area, South China. After removal of a recent viscous remanent magnetization below 150 °C, an intermediate temperature component (ITC; Dg = 27.6°, Ig = 45.3°, N = 12 sites, kg = 184.3, α95 = 3.2° for JLWE; Dg = 22°, Ig = 45.3°, N = 11 sites, kg = 789.2, α95 = 1.6° for JLWS; and Dg = 25.5°, Ig = 52.5°, N = 6 sites, kg = 533.4, α95 = 2.9° for SXRJ) was removed below 300 °C which coincides with the Jurassic results from South China, suggesting a pervasive Jurassic remagnetization. In addition, a high temperature component (HTC; Ds = 84.8°, Is = 19.2°, N = 9 sites, ks = 35.5, α95 = 8.8° for JLWE; Ds = 74.1°, Is = 49.4°, N = 7 sites, ks = 218.9, α95 = 4.1° for JLWS; and Ds = 89.5°, Is = 30.7°, N = 8 sites, ks = 129.2, α95 = 4.9° for SXRJ) was isolated between 300 and 480-540 °C. Rock magnetic and SEM studies suggest that the ITC and HTC are carried by pyrrhotite and magnetite, respectively. SEM observations also demonstrate the occurrence of massive authigenic magnetite in cavities or cracks, mineralogical changes from pyrite to Fe oxides, and the reaction between gypsum and Fe oxides. Based on similarities to the Silurian poles of South China, together with the SEM observations, we suggest that the HTC from the JLWE and SXRJ sections is a Silurian age remagnetization. The oxidation of iron sulphides and thermochemical sulphate reduction induced by the

Dietary exposure to aluminium of urban residents from cities in South China.

PubMed

Jiang, Qi; Wang, Jing; Li, Min; Liang, Xuxia; Dai, Guangwei; Hu, Zhikun; Wen, Jian; Huang, Qiong; Zhang, Yonghui

2013-01-01

A dietary survey was conducted over three consecutive days by using 24-hour dietary recall in the Pearl River Delta of South China to investigate the dietary consumption status. A total of 1702 food samples, 22 food groups, were collected, and aluminium concentrations of foods were determined by using ICP-MS. Weekly dietary exposure to aluminium of the average urban residents of South China was estimated to be 1.5 mg kg⁻¹ body weight, which amounted to 76% of the provisional tolerable weekly intake. Wheat-made products (53.5%) contributed most to the dietary exposure, followed by vegetables (12.2%). The high-level consumers' weekly exposure to aluminium was 11.1 mg kg⁻¹ body weight, which amounted to 407% of the provisional tolerable weekly intake. The results indicated that the general urban residents in South China might be safe from aluminium exposure, but the high-level consumers might be at some risk of aluminium exposure. The foods contributing to aluminium exposure were processed food with aluminium-containing food additives. It is necessary to take effective measures to control the overuse of aluminium-containing food additives.

Eocene Podocarpium (Leguminosae) from South China and its biogeographic implications.

PubMed

Xu, Qingqing; Qiu, Jue; Zhou, Zhekun; Jin, Jianhua

2015-01-01

Podocarpium A. Braun ex Stizenberger is one of the most common legumes in the Neogene of Eurasia, including fossil fruits, seeds, leaves, and possible flower and pollen grains. This genus is not completely consistent with any extant genera according to gross morphological characters and poorly preserved cuticular structures reported in previous studies. The fossil pods collected from the coal-bearing series of the Changchang Basin of Hainan Island and Maoming Basin of Guangdong, South China, are examined by morphologically comparative work, with special reference to venation patterns and placental position. These distinctive features, as well as the ovule development of pods from different developmental stages and the epidermal structure of the pods, as distinguished from previous records lead to the conclusion that these fossils can be recognized as a new species of Podocarpium, P. eocenicum sp. nov. This new discovery indicates that Podocarpium had arrived in South China by the Eocene. Investigation on the fossil records of this extinct genus shows that P. eocenicum is the earliest and lowest latitude fossil data. The possible occurrence pattern of this genus is revealed as follows: Podocarpium had distributed in the South China at least in the middle Eocene, and then migrated to Europe during the Oligocene; in the Miocene this genus reached its peak in Eurasia, spreading extensively across subtropical areas to warm temperate areas; finally, Podocarpium shrank rapidly and became extinct in Eurasia during the Pliocene.

The Evolution History of South China Sea: a Synthesis of Recent Geophysical, Geological, and Geochemical Results

NASA Astrophysics Data System (ADS)

Xue, M.; Li, L.; Chen, L.

2016-12-01

South China Sea (SCS) is located in the continental margin of Eurasia plate, where different geological blocks/tectonic plates interact. The dynamic mechanism of the formation of South China Sea (SCS) has been debated for decades. In this study, we first synthesize our geophysical results obtained in South China Sea, including an updated 3D velocity model from surface tomography using surrounding land stations and regional earthquakes, and shear wave splitting results obtained at surrounding land stations and OBS, using local, regional, and teleseismic earthquakes. The observed splitting results in South China Sea are complex: the fast polarization direction beneath the central basin is approximately NE-SW, nearly parallel to the extinct ridge in the central basin of SCS; however, the fast axis within the slab is trench-parallel outside the ridge subduction region. In 3D velocity models, subducting slabs are observed as dipping high velocity anomalies, and discontinuous low velocities are observed above the subduction slab, as well as in the basin. How the splitting observations are connected with the velocity models? How observations are linked to one another? How are the observations in central basin linked with surrounding region? We are aiming to link these observations themselves as well as with newly published results from geophysics, geochemistry, and geology in this region. Such a synthesis will improve our understanding about the evolution of South China Sea and facilitate new ideas.

Distribution and Diversity of Microbial Eukaryotes in Bathypelagic Waters of the South China Sea.

PubMed

Xu, Dapeng; Jiao, Nianzhi; Ren, Rui; Warren, Alan

2017-05-01

Little is known about the biodiversity of microbial eukaryotes in the South China Sea, especially in waters at bathyal depths. Here, we employed SSU rDNA gene sequencing to reveal the diversity and community structure across depth and distance gradients in the South China Sea. Vertically, the highest alpha diversity was found at 75-m depth. The communities of microbial eukaryotes were clustered into shallow-, middle-, and deep-water groups according to the depth from which they were collected, indicating a depth-related diversity and distribution pattern. Rhizaria sequences dominated the microeukaryote community and occurred in all samples except those from less than 50-m deep, being most abundant near the sea floor where they contributed ca. 64-97% and 40-74% of the total sequences and OTUs recovered, respectively. A large portion of rhizarian OTUs has neither a nearest named neighbor nor a nearest neighbor in the GenBank database which indicated the presence of new phylotypes in the South China Sea. Given their overwhelming abundance and richness, further phylogenetic analysis of rhizarians were performed and three new genetic clusters were revealed containing sequences retrieved from the deep waters of the South China Sea. Our results shed light on the diversity and community structure of microbial eukaryotes in this not yet fully explored area. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

Greenhouse Gas Emissions from Cotton Field under Different Irrigation Methods and Fertilization Regimes in Arid Northwestern China

PubMed Central

Guo, Wei; Feng, Jinfei; Li, Lanhai; Yang, Haishui; Wang, Xiaohua; Bian, Xinmin

2014-01-01

Drip irrigation is broadly extended in order to save water in the arid cotton production region of China. Biochar is thought to be a useful soil amendment to reduce greenhouse gas (GHG) emissions. Here, a field study was conducted to compare the emissions of nitrous oxide (N2O) and methane (CH4) under different irrigation methods (drip irrigation (D) and furrow irrigation (F)) and fertilization regimes (conventional fertilization (C) and conventional fertilization + biochar (B)) during the cotton growth season. The accumulated N2O emissions were significantly lower with FB, DC, and DB than with FC by 28.8%, 36.1%, and 37.6%, while accumulated CH4 uptake was 264.5%, 226.7%, and 154.2% higher with DC, DB, and FC than that with FB, respectively. Irrigation methods showed a significant effect on total global warming potential (GWP) and yield-scaled GWP (P < 0.01). DC and DB showed higher cotton yield, water use efficiency (WUE), and lower yield-scaled GWP, as compared with FC and FB. This suggests that in northwestern China mulched-drip irrigation should be a better approach to increase cotton yield with depressed GHG. In addition, biochar addition increased CH4 emissions while it decreased N2O emissions. PMID:25133229

Remagnetization mechanisms in Triassic red beds from South China

NASA Astrophysics Data System (ADS)

Jiang, Zhaoxia; Liu, Qingsong; Dekkers, Mark J.; Zhao, Xiang; Roberts, Andrew P.; Yang, Zhenyu; Jin, Chunsheng; Liu, Jianxing

2017-12-01

Paleogeographic reconstructions based on paleomagnetic data rely on the reliability of the natural remanent magnetization (NRM) as a primary geomagnetic signal. Remagnetizations, however, can be common in many rock types, including late Paleozoic and Mesozoic red beds, and they complicate paleogeographic interpretations. Extracting the primary NRM from partially remagnetized rocks, and understanding the remagnetization mechanism are important in these contexts. We carried out a systematic paleomagnetic study of red bed samples from the Triassic Huangmaqing Formation, Nanjing (32.0°N, 118.9°E), South China. Two NRM components carried by secondary and primary hematite are isolated in 47 of the 94 samples studied, where the latter component has a direction in stratigraphic coordinates of D = 29.2 °, I = 34.6 ° (α95 = 10.9 °, 47 samples from 6 sites) that yields a paleopole of λ = 60.8°N, ϕ = 228.1°E, dp / dm = 12.5 / 7.2, which is consistent with Triassic pole positions for the South China Block. A secondary chemical remanent magnetization (CRM) (D = 227.1 °, I = 80.8 °, α95 = 7.3 °) is documented in all 94 samples from 10 sites and is carried by pigmentary hematite that is inferred to have been generated by magnetite oxidation during orogenic activity. This secondary component has steep inclinations and is interpreted to have been influenced by a combination of the remanence carried by original parent magnetite, the orogenic stress field, and the prevailing geomagnetic field direction during deformation. This CRM direction is recorded commonly by red beds from the South China Block, and is significant for regional tectonic studies in the area.

Comparison of publication trends in dermatology among Japan, South Korea and Mainland China.

PubMed

Man, Huibin; Xin, Shujun; Bi, Weiping; Lv, Chengzhi; Mauro, Theodora M; Elias, Peter M; Man, Mao-Qiang

2014-01-09

We previously showed that the number of publications in dermatology is increasing year by year, and positively correlates with improved economic conditions in mainland China, a still developing Asian country. However, the characteristics of publications in dermatology departments in more developed Asian countries such as Japan and South Korea are unknown. In the present study, publications from 2003 through 2012 in dermatology in Japan, South Korea and mainland China were characterized. All data were obtained from http://www.pubmed.com. Dermatology departments in Japan published 4,094 papers, while mainland China and South Korea published 1528 and 1,758 articles, respectively. 48% of articles from dermatology in Japan were original research and 36% were case reports; The number of publications in Japan remained stable over time, but the overall impact factors per paper increased linearly over the last 10 year period (p < 0.05). In mainland China, 67% of articles from dermatology were original research, while 19% were case reports; The number of publications and their impact factors per paper increased markedly. In South Korea, 65% of articles from dermatology were original research and 20% were case reports. The impact factors per paper remained unchanged, despite of the fact that the number of publications increased over the last 10 year period (r2 = 0.6820, p = 0.0032). Only mainland China showed a positive correlation of the number of publications with gross domestic product per capita during this study period. These results suggest that the total number of publications in dermatology correlates with economic conditions only in developing country, but not in more developed countries in Asia. The extent of economic development could determine both the publication quantity and quality.

Comparison of publication trends in dermatology among Japan, South Korea and Mainland China

PubMed Central

2014-01-01

Background We previously showed that the number of publications in dermatology is increasing year by year, and positively correlates with improved economic conditions in mainland China, a still developing Asian country. However, the characteristics of publications in dermatology departments in more developed Asian countries such as Japan and South Korea are unknown. Methods In the present study, publications from 2003 through 2012 in dermatology in Japan, South Korea and mainland China were characterized. All data were obtained from http://www.pubmed.com. Results Dermatology departments in Japan published 4,094 papers, while mainland China and South Korea published 1528 and 1,758 articles, respectively. 48% of articles from dermatology in Japan were original research and 36% were case reports; The number of publications in Japan remained stable over time, but the overall impact factors per paper increased linearly over the last 10 year period (p < 0.05). In mainland China, 67% of articles from dermatology were original research, while 19% were case reports; The number of publications and their impact factors per paper increased markedly. In South Korea, 65% of articles from dermatology were original research and 20% were case reports. The impact factors per paper remained unchanged, despite of the fact that the number of publications increased over the last 10 year period (r2 = 0.6820, p = 0.0032). Only mainland China showed a positive correlation of the number of publications with gross domestic product per capita during this study period. Conclusions These results suggest that the total number of publications in dermatology correlates with economic conditions only in developing country, but not in more developed countries in Asia. The extent of economic development could determine both the publication quantity and quality. PMID:24405832

Paliurus Fruits from the Oligocene of South China and Their Phytogeographic Implications

PubMed Central

Dong, Jun-Ling; Sun, Bai-Nian; Ma, Fu-Jun; Wang, Qiu-Jun; Jin, Pei-Hong; Wang, Wen-Jia; Deng, Peng; Yang, Yi; Li, Xiao-Jing

2015-01-01

Paliurus favonii Unger is recognized and described based on fruits from the Oligocene Ningming flora of Guangxi, South China. Characteristics of the present specimens include circular winged fruits that are 10.0–11.5 mm in diameter with a central endocarp at 3.0 to 4.0 mm in diameter. The specimens fall into the morphological range of the fossil species P. favonii, which has been observed in other Cenozoic sites in the Northern Hemisphere. The present discovery represents the lowest latitude distribution of P. favonii in the world, and we are presenting the first P. favonii fossil described with detailed cuticular characteristics from China. Further, this finding demonstrates that the genus existed in the Oligocene Ningming region, South China, and provides new information for understanding the fossil history. The dispersal mode for winged fossils demonstrates that wind dispersal is well-represented in the Oligocene Ningming flora. PMID:26536607

Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports

PubMed Central

Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

2016-01-01

A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea. PMID:27410682

Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports.

PubMed

Daryabor, Farshid; Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

2016-01-01

A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea.

Use of a Survey to Assess the Environmental Exposure and Family Perception to Lead in Children (<6 Years) in Four Valley Cities, Northwestern China.

PubMed

Sun, Xuemeng; Li, Xiaoping; Liu, Dongying; Yang, Tao; Zhao, Yanan; Wu, Ting; Cai, Yue; Ai, Yuwei; Zhang, Xu; Wang, Jiwen; Yang, Rui; Yu, Hongtao; Mielke, Howard W

2018-04-12

With the growth of industry, the extensive use of lead, and urban expansion in Northwestern Valley Cities (NVC) China, there is probable reason for presuming an increasing risk of lead exposure. However, little is known about the lead exposure of children less than 6 years old in NVC. As a first investigation, this study uses a survey to systematically determine the influences of various risk factors within the family environment, parents' background, children's behavior, mother's behavior during pregnancy, and parental perception about children's blood lead (CBL). A total of 596 families were recruited from the general population in Urumqi, Lanzhou, Xining and Yan'an. Parents, and their children (<6 years old), were asked about the environment and behaviors which could possibly relate with lead exposure. The results indicated that in the typical NVC of China, children's environment and behavior, parents' education level, and mother's pregnancy behavior, were associated with potential CBL. It was noted that not all parents in NVC China recognized the importance of children's lead exposure. Therefore, children's health care and medical screening campaigns need to be designed to improve family's fundamental knowledge of lead hazards, associated health effects, and prevention in the NVC of China.

Geology and timing of mineralization at the Cangshang gold deposit, north-western Jiaodong Peninsula, China

USGS Publications Warehouse

Zhang, X.; Cawood, Peter A.; Wilde, S.A.; Liu, R.; Song, H.; Li, W.; Snee, L.W.

2003-01-01

The Cangshang gold deposit of the northwestern Jiaodong Peninsula contains reserves of greater than 50 tonnes (t) and is developed by the largest open pit gold mine in China. This deposit is a Jiaojia-style (i.e. disseminated-and-veinlet) deposit. It is controlled by the San-Cang fault zone, which trends ???040?? and dips 40-75??SE at the mine site. The main (no. 1) orebody lies between a hanging wall of Precambrian metamorphic rocks (mainly amphibolite) of the Fenzishan Group and a footwall composed of the Mesozoic Linglong granitoid. The ore zone is mainly composed of pyritized, sericitized and silicified granitoid, which has undergone variable degrees of cataclasis. SHRIMP U-Pb dating of zircon indicates that the protolith of the hanging wall amphibolite was formed at 2530 ?? 17 Ma and underwent metamorphism at 1852 ?? 37 Ma. The footwall granodiorite has been dated at 166 ?? 4 Ma, whereas zircons from the ore zone yield a younger age of 154 ?? 5 Ma. Cathodoluminescence images of zircons from the granodiorite and ore zone show oscillatory zonation indicative of an igneous origin for both and the ages of these zircons, therefore, are all interpreted to be representative of magmatic crystallization. Dating of sericite by 40Ar-39Ar has been used to directly determine the timing of formation of the Cangshang deposit, providing the first time absolute age on formation of the Jiaojia-style gold deposits. The well-defined age of 121.3 ?? 0.2 Ma provides the precise timing of gold mineralization at the Cangshang deposit. This age is consistent with those of Linglong-style (vein type) gold mineralization, also from the north-western Jiaodong Peninsula, at between 126 and 120 Ma. Therefore, our work indicates that both styles of gold deposits in the Jiaodong Peninsula were formed during the same mineralization event.

Rifting, drifting, convergence and orogenesis: The sedimentary record of the Wernecke Supergroup on the Paleoproterozoic margin of northwestern Columbia

NASA Astrophysics Data System (ADS)

Furlanetto, F.; Thorkelson, D. J.; Rainbird, R.; Davis, B.; Gibson, D.; Marshall, D. D.

2015-12-01

The Wernecke Supergroup was deposited when the northwestern margin of Laurentia was undergoing major adjustments related to the assembly of the supercontinent Columbia (Nuna) in the late Paleoproterozoic. The succession was deposited between ca. 1663 and ca. 1620 Ma in two clastic to carbonate grand cycles. The detrital zircon population is bimodal, reflecting derivation from cratonic Laurentia. Basin shallowing at the end of the second grand cycle corresponds to a significant younging of detrital zircon populations. Specifically, the late Paleoproterozoic peak of zircon ages shifted from ca. 1900 Ma to ca. 1825 Ma, and the proportion of Archaean and early Paleoproterozoic zircon decreased. These shifts were caused by a change in drainage pattern in northern Laurentia during an early phase of the Forward orogeny, farther inland. The orogeny also led to inversion of the broadly correlative Hornby Bay Group. Zircon younger than 1.75 Ga is present throughout the sedimentary succession and may have originated from small igneous suites in northern Laurentia or larger magmatic arc terranes of the Yavapai and early Mazatzal orogenies in southern Laurentia. Eastern and southern Australia and the intervening Bonnetian arc may have contributed. The Wernecke Supergroup shares similar detrital zircon age and Nd isotope signatures with the Hornby Bay, Muskwa, Athabasca and Thelon successions of Canada; the Tarcoola Formation, Willyama Supergroup, and Isan Supergroup of Australia; and of the Dongchuan-Dahongshan-Hondo successions of South China. These similarities are compelling evidence for a shared depositional system in the late Paleoproterozoic. Western Columbia may have had a dynamic SWEAT-like configuration with Australia, East Antarctica and South China moving in a complex manner near the margin of western Laurentia. All of the continents except for South China underwent post-Wernecke tectonism during the Racklan, Forward, Olarian, Isan, Mazatzal and related orogenies, ca

Review of the circulation in the Beibu Gulf, South China Sea

NASA Astrophysics Data System (ADS)

Gao, Jingsong; Wu, Guidan; Ya, Hanzheng

2017-04-01

Although Beibu Gulf holds a significant geographical location and is rich in fishery resources, it has attracted only limited attention from researchers in recent decades. This study summarizes the conclusions based on the observations and model results regarding the circulation and cold water mass in the Beibu Gulf to provide a reference for further research. Affected by wind and density gradient, the spring circulation may be gulf-scale cyclonic and nested with an enclosed cyclonic gyre in the northern gulf and unclosed cyclonic gyre in the southern gulf. Meanwhile, the mechanisms of summer circulation remain controversial. Along with the results of a new numerical model, historical observations suggest that summer circulation is cyclonic and anticyclonic in the northern and southern gulfs, respectively. The northern and southern gulfs are mainly influenced by wind stress curl and South China Sea current, respectively. Similarly, although different views regarding the structure of winter circulation have been presented, a large amount of evidence supports the existence of two cyclonic gyres in the northern and southern gulfs. In addition, a southwestward current off the northwestern coast of Hainan Island is present. The circulation structure in the fall is similar to that in winter. However, the cyclonic gyre in the southern Gulf has a greater tendency to intrude northwards into the Beibu Gulf in fall than in winter, and the currents off the coast of Vietnam and the northwestern coast of Hainan Island are weaker in fall than those in winter. Most studies indicate that winter boreal circulation is driven by the monsoon wind. The most recent observations and model results suggest that the current in the Qiongzhou Strait (QS) is eastward on certain days in the boreal summer and is affected by the difference between the sea levels of the two ends of the QS and tidal rectification. Correspondingly, the volume transport is approximately -0.1 Sv (minus sign represents

Geological history of the Cretaceous ophiolitic complexes of northwestern South America (Colombian Andes)

NASA Astrophysics Data System (ADS)

Bourgois, Jacques; Toussaint, Jean-François; Gonzalez, Humberto; Azema, Jacques; Calle, Bernardo; Desmet, Alain; Murcia, Luis A.; Acevedo, Alvaro P.; Parra, Eduardo; Tournon, Jean

1987-12-01

The Western Cordillera of Colombia was formed by intense alpine-type nappe-forming folding and thrusting. The Cretaceous (80-120 Ma B.P.) tholeiitic material of the Western Cordilleran nappes has been obducted onto the Paleozoic and Precambrian polymetamorphic micaschists and gneiss of the Central Cordillera. Near Yarumal, the Antioquia batholith (60-80 Ma B.P.) intrudes both obducted Cretaceous oceanic material and the polymetamorphic basement rock of the Central Cordillera. Therefore, nappe emplacement and obduction onto the Central Cordillera occurred during Late Senonian to Early Paleocene. The nappes travelled from northwest to southeast so that the highest unit, the Rio Calima nappe therefore has the most northwestern source, whereas the lowest units originated from a more southeastward direction. Sedimentological analysis of the volcanoclastic and sandy turbidite material from each unit suggests a marginal marine environment. During Cretaceous times the opening of this marginal sea, from now on called the "Colombia marginal basin", probably originated by detachment of a block from the South American continent related to the Farallon-South America plate convergence. In the Popayan area (southern Colombia), the Central Cordilleran basement exhibits glaucophane schist facies metamorphism. This high pressure low temperature metamorphism is of Early Cretaceous (125 Ma B.P.) age and is related to an undated metaophiolitic complex. The ophiolitic material originating from the Western Cordilleran is thrust over both the blueschist belt and the metaophiolitic complex. These data suggest that the "Occidente Colombiano" suffered at least two phases of ophiolitic obduction during Mesozoic time.

Investigation of Soil Biodiversity in South East China

NASA Astrophysics Data System (ADS)

Gao, R.; Li, M.; Li, Z.; Chen, Y.; Liang, Y.; Ye, J.

2017-12-01

The United Nations had declared 2015 to be the International Year of Soil to bring to mind the significance of this natural resource. We will describe our initial collaborative effort to investigate soil biodiversity at an organic farm located in South East China. In this session, we will share our early experiences exploring conventional soil biodiversity methods, as well as offer suggestions for future research.

Diversity of Sternaspidae (Annelida: Terebellida) in the South China Sea, with descriptions of four new species.

PubMed

Wu, Xuwen; Xu, Kuidong

2017-03-20

Sternaspidae is one of the most common groups of polychaetes in the South China Sea, where however, the knowledge of its diversity and distribution is insufficiently understood and reports of the European species Sternaspis scutata are misidentifications. Based on the examination of material deposited in the Marine Biological Museum of the Chinese Academy of Sciences, we made a comprehensive investigation on the sternaspid polychaetes in the northern South China Sea. Five species belonging to two genera are described: Petersenaspis salazari sp. nov., Sternaspis radiata sp. nov., S. spinosa Sluiter, 1882, S. sunae sp. nov. and S. wui sp. nov. A taxonomic key to ten species of Sternaspidae found in the South China Sea is provided.

China’s Rise in South America: The Partner of Choice

DTIC Science & Technology

2018-03-01

insufficient amount of natural resources and agricultural production in Southeast Asia to maintain its economy and citizenry.6 This “win-win” financing...its agricultural products, as the U.S. government does through subsidies, therefore creating more cost-effective commodity trade for both countries.19...This makes trade much between China and South America much easier than the conflict-laden agricultural trade between the United States and South

ON the interaction of the north andes plate with the caribbean and south american plates in northwestern south america from gps geodesy and seismic data

NASA Astrophysics Data System (ADS)

Pérez, Omar J.; Wesnousky, Steven G.; De La Rosa, Roberto; Márquez, Julio; Uzcátegui, Redescal; Quintero, Christian; Liberal, Luis; Mora-Páez, Héctor; Szeliga, Walter

2018-06-01

We examine the hypocentral distribution of seismicity and a series of geodetic velocity vectors obtained from Global Positioning System (GPS) observations between 1994 and 2015 both off-shore and mainland northwestern South America [66° W - 77° W; 8° N - 14° N]. Our analysis, that includes a kinematic block modeling, shows that east of the Caribbean-South American-North Andes plates triple junction at ˜68° W; 10.7° N, right-lateral easterly oriented shear motion (˜19.6 ± 2.0 mm/yr) between the Caribbean and South-America plates is split along two easterly striking, right-lateral strike slip subparallel fault zones: the San Sebastián fault that runs offshore the Venezuelan coast and slips about 17.0 ± 0.5 mm/yr, and the La Victoria fault, located onshore to the south, which is accumulating strain equivalent to 2.6 ± 0.4 mm/yr. West of the triple junction, relative right-lateral motion between the Caribbean and South American plates is mostly divided between the Morrocoy and Boconó fault systems which strike northwest and southwest from the triple junction, respectively, and bound the intervening North Andes plate that shows an easterly oriented geodetic slip of 15.0 ± 1.0 mm/yr relative to the South American plate. Slip on the Morrocoy fault is right-lateral and transtensional. Motion across the Boconó fault is also right-lateral but instead transpressional, divided between ˜9 to 11 mm/yr of right-slip on the Boconó fault and 2 to 5 mm/yr of convergence across adjacent and subparallel thrust faults. Farther west of the triple junction, ˜800 km away in northern Colombia, the Caribbean plate subducts to the southeast beneath the North Andes plate at a geodetically estimated rate of ˜5-7 mm/yr.

Under the Dragon’s Wing: A Strategic Approach to China’s Militarization Efforts of its Artificial Islands in the South China Sea

DTIC Science & Technology

2017-06-09

environments elsewhere in the world. When thinking about the SCS, it is helpful to imagine other bodies of water in the world with similar characteristics...Operation Planning. Washington, DC: Government Printing Office. Kazianis, Harry J. 2014. “America’s Dangerous $5 Trillion Dollar Bet in the South China...dollar- bet -the-south-china-10857. Kem, Jack D. 2012. Planning for Action: Campaign Concepts and Tools. Ft. Leavenworth, KS: U.S. Army Command and

Effects of Vegetation Type on Soil Carbon Dynamics Along the Kaidu River in the Yanqi Basin of Northwestern China

NASA Astrophysics Data System (ADS)

Wang, J.; Wang, X.; Wang, W.

2010-12-01

The Kaidu River originates from the central southern slopes of the Tian Shan from where it flows through the Yulduz Basin and the Yanqi Basin into Lake Bosten. There has been intensive agricultural development along the Kaidu River in the Yanqi Basin. Corn and pepper are two of the main crops. Here, we present a study includes comparisons of soil organic carbon (SOC) between typical native vegtation types (e.g., Glycyrhiza uralensis Fisch, Achnatherum splendens and Sophora alopecuroides Linn) and agricultural crops (i.e., corn and pepper). Fourteen soil pits were sampled at five depths (0-5, 5-15, 15-30, 30-50 and 50-100 cm) in August 2010 (Figure 1). Soil organic matter are determined using the traditional Walkley and Black method and Loss-on-ignition at 375°C for 17 hours. As expected, agricultural soils contain higher SOC than non-agriculatural lands. Native vegetation has various effects on vertical distribution of SOC. We discuss how root system influences SOC dynamics along the Kaidu River in the central Xinjiang, China. Fig. 1. Map of sampling sites along the Kaidu River in northwestern China.

First record of Podocarpoid fossil wood in South China

PubMed Central

Li, Long; Jin, Jian-Hua; Quan, Cheng; Oskolski, Alexei A.

2016-01-01

A new species of fossil conifer wood, Podocarpoxylon donghuaiense sp. nov., is described from the late Eocene of Nadu Formation in Baise Basin of the Guangxi Province, South China. This fossil wood is characterized by distinct growth rings, circular to oval tracheids in cross section, 1–2-seriate opposite pits on radial tracheid walls, uniseriate (rarely biseriate) rays, smooth end walls of ray parenchyma cells, and the absence of resin ducts, suggesting its affinity to Podocarpaceae. The new species is distinctive from other Cenozoic woods ascribed to this family by the combination of distinctive growth rings, the absence of axial parenchyma, the occurrence of bordered pits on tangential tracheid walls, and the occurrence of 3–4 cuppressoid or taxodioid pits on cross-fields. This represents the first record of podocarpoid fossil wood in South China and provides fossil evidence for the early dispersal and diversification of Podocarpaceae in eastern Asia as well as for mild temperate seasonal climate in this region during the late Eocene. PMID:27571780

Genome Sequence of Canine Parvovirus Strain SC02/2011, Isolated from a Puppy with Severe Diarrhea in South China

PubMed Central

Cheng, Yi; Ji, Yikuan; Wang, Yu; Sun, Leilei; Huang, Jiaxin

2012-01-01

A widespread hemorrhagic gastroenteritis in young dogs occurred in South China. A virulent field canine parvovirus (CPV) strain, SC02/2011, was isolated from a puppy showing enteric signs in Guangdong, China. The genome of CPV strain SC02/2011 was sequenced and analyzed, which will promote a better understanding of the molecular epidemiology and genetic diversity of CPV field isolates in South China. PMID:23166228

Education in Rural Areas of China and South Africa: Comparative Perspectives on Policy and Educational Management. Comparative Perspectives: Education in China & South Africa.

ERIC Educational Resources Information Center

Gordon, Adele; Wang, Qiang

This report on the educational systems in China and South Africa compares the policies and processes of the two countries as they attempt to expand and improve rural education. Both countries experienced a major political upheaval, and even though there is a 50-year time lag between these events, political changes ushered in radical educational…

Seismic anisotropy beneath South China Sea: using SKS splitting to constrain mantle flow

NASA Astrophysics Data System (ADS)

Xue, M.; Le, K.; Yang, T.

2011-12-01

The evolution of South China Sea is under debate and several hypotheses have been proposed: (1) The collision of India plate and Eurasia plate; (2) the backward movement of the Pacific subduction plate; (3) mantle upwelling; and (4) combinations of above hypotheses. All these causal mechanisms emphasize the contributions of deep structures to the evolution of South China Sea. In this study we use earthquake data recorded by seismic stations surrounding South China Sea to constrain mantle flow beneath. To fill the vacancy of seismic data in Viet Nam, we deployed 4 seismic stations (VT01-VT04) in a roughly north - south orientation in Viet Nam in Nov. 2009. We combine the VT dataset with the AD and MY datasets from IRIS and select 81 events for SKS splitting analysis. Measurements were made at 11 stations using Wolfe and Silver (1998)'s multi-event stacking procedure. Our observed splitting directions in Vietnam are generally consistent with those of Bai et. al. (2009) . In northern Vietnam, the splitting times are around 1 sec and the fast directions are NWW-SEE, parallel to the absolute plate motion as well as the motion of the Earth surface, implying the crust and the mantle are coupled in this region and is moving as a result of the collision of India and China. While in southern Vietnam and Malaya, the fast directions are NE-SW, almost perpendicular to the absolute plate motion as well as the surface motion of Eurasia plate. However, the observed NE-SW is parallel to the subduction direction of the Australian plate, which might be caused by the mantle flow along NE-SW induced by the subduction.

Numerical assessment of factors affecting nonlinear internal waves in the South China Sea

NASA Astrophysics Data System (ADS)

Li, Qiang

2014-02-01

Nonlinear internal waves in the South China Sea exhibit diverse characteristics, which are associated with the complex conditions in Luzon Strait, such as the double ridge topography, the Earth’s rotation, variations in stratification and the background current induced by the Kuroshio. These effects are individually assessed using the MITgcm. The performance of the model is first validated through comparison with field observations. Because of in-phased ray interaction, the western ridge in Luzon Strait intensifies the semidiurnal internal tides generated from the eastern ridge, thus reinforcing the formation of nonlinear internal waves. However, the ray interaction for K1 forcing becomes anti-phased so that the K1 internal tide generation is reduced by the western ridge. Not only does the rotational dispersion suppress internal tide generation, it also inhibits nonlinear steepening and consequent internal solitary wave formation. As a joint effect, the double ridges and the rotational dispersion result in a paradoxical phenomenon: diurnal barotropic tidal forcing is dominant in Luzon Strait, but semidiurnal internal tides prevail in the deep basin of the South China Sea. The seasonal variation of the Kuroshio is consistent with the seasonal appearance of nonlinear internal waves in the South China Sea. The model results show that the westward inflow due to the Kuroshio intrusion reduces the amplitude of internal tides in the South China Sea, causing the weakening or absence of internal solitary waves. Winter stratification cannot account for the significant reduction of nonlinear internal waves, because the amplitude growth of internal tides due to increased thermocline tilting counteracts the reduced nonlinearity caused by thermocline deepening.

Stability of submarine slopes in the northern South China Sea: a numerical approach

NASA Astrophysics Data System (ADS)

Zhang, Liang; Luan, Xiwu

2013-01-01

Submarine landslides occur frequently on most continental margins. They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations. In this paper, submarine slope stability is evaluated using a 2D limit equilibrium method. Considerations of slope, sediment, and triggering force on the factor of safety (FOS) were calculated in drained and undrained ( Φ=0) cases. Results show that submarine slopes are stable when the slope is <16° under static conditions and without a weak interlayer. With a weak interlayer, slopes are stable at <18° in the drained case and at <9° in the undrained case. Earthquake loading can drastically reduce the shear strength of sediment with increased pore water pressure. The slope became unstable at >13° with earthquake peak ground acceleration (PGA) of 0.5 g; whereas with a weak layer, a PGA of 0.2 g could trigger instability at slopes >10°, and >3° for PGA of 0.5 g. The northern slope of the South China Sea is geomorphologically stable under static conditions. However, because of the possibility of high PGA at the eastern margin of the South China Sea, submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope. Therefore, submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake, the most important factor for triggering submarine slides on the northern slope of the South China Sea. Considering the distribution of PGA, we consider the northern slope of the South China Sea to be stable, excluding the Taiwan Bank slope, which is tectonically active.

Middle-Upper Permian carbon isotope stratigraphy at Chaotian, South China: Pre-extinction multiple upwelling of oxygen-depleted water onto continental shelf

NASA Astrophysics Data System (ADS)

Saitoh, Masafumi; Isozaki, Yukio; Ueno, Yuichiro; Yoshida, Naohiro; Yao, Jianxin; Ji, Zhansheng

2013-05-01

negative excursions at Chaotian are apparently correlated with the previously proposed large negative excursion in the middle Capitanian in South China, the age difference according to the biostratigraphic constraints clearly exclude this interpretation. The isotopic negative excursions at Chaotian are unique and no similar isotopic signal in the same period has been reported elsewhere. The multiple upwelling of oxygen-depleted waters onto the euphotic shelf may have represented local phenomena that occurred solely around northwestern South China.

Yardangs in the Qaidam Basin, northwestern China: Distribution and morphology

NASA Astrophysics Data System (ADS)

Li, Jiyan; Dong, Zhibao; Qian, Guangqiang; Zhang, Zhengcai; Luo, Wanyin; Lu, Junfeng; Wang, Meng

2016-03-01

The northwestern Qaidam Basin exposes one of the largest and highest elevation yardang fields on Earth. The aim of the present study was to describe the distribution and morphology of these yardangs, and analyze the factors responsible for the distribution pattern of these aeolian landforms. The yardang fields are bounded by piedmont alluvial-diluvial fans from the mountain ranges surrounding the basin, except in the south, where they are bounded by dune fields, dry salt flats, lakes, and rivers. This distribution pattern can be attributed to regional tectogenesis and its corresponding environmental impacts. The morphology of the yardangs varies considerably in response to the diverse factors that control their formation and evolution. Long-ridge yardangs are mainly located in the northernmost part of the yardang field, and the long ridges are gradually dissected into smaller ridges in the downwind direction. Further downwind, the convergence of northerly and northwesterly winds and the effects of temporary runoff cause the ridges to gradually transition into mesa yardangs. Saw-toothed crests, and conical and pyramidal yardangs, occur in groups on folded brachyanticlinal structures. Typical whaleback yardangs are found in the southeast, at the northern margin of Dabuxun Lake. Morphological parameters vary among the yardang types. The orientation of the yardangs in the northernmost area is nearly N-S, with a transition towards NW-SE in the southernmost area in response to a change in the dominant wind direction that results from the orientations and positions of the mountain ranges that surround the basin.

Occurrence of PPCPs in Pearl River Estuary and South China Sea

NASA Astrophysics Data System (ADS)

Fisch, Kathrin; Waniek, Joanna J.; Schulz-Bull, Detlef E.

2017-04-01

The development of a coastal megacity has put the South China Sea under human induced stress. Pharmaceuticals and personal care products (PPCPs) are ubiquitous contaminants and can be used as anthropogenic indicators for pollution of the marine environment. They enter the marine environment indirectly via waste water or directly due to recreational activities. PPCPs make up a group of different pharmaceuticals such as antibiotic, anti-inflammatories etc. and personal care products such as UV-filters. A mayor concern is the unknown fate and the effect these pollutants on the marine environment and especially its organisms. In some studies it was proven that some of these PPCPs have an endocrine disrupting and/or a subtle chronic effect on aquatic organisms. They are of concern for the health of the marine environment and may have an effect on human health. With our study we could determine the occurrence of PPCPs in the Pearl River estuary and the South China Sea. Salicylic acid (metabolite of acetylsalicylic acid) and octocrylene (UV-filter) were found in the open Sea in low ng/L concentration. Octocrylene is used in sunscreen and as a light stabilizer in paints and polymer-based products. It is of environmental concern because of its potential to be bioaccumulative. In addition to our findings in the open South China Sea, could we detect PPCPs, especially antibiotics, in higher ng/L-concentrations in the Pearl River Estuary.

Perceived Environmental Pollution and Its Impact on Health in China, Japan, and South Korea.

PubMed

Kamimura, Akiko; Armenta, Bianca; Nourian, Maziar; Assasnik, Nushean; Nourian, Kimiya; Chernenko, Alla

2017-01-01

Environmental pollution is a significant global issue. Both objective (scientifically measured) environmental pollution and perceived levels of pollution are important predictors of self-reported health. The purpose of this study was to compare the associations between perceived environmental pollution and health in China, Japan, and South Korea. Data were obtained from the East Asian Social Survey and the Cross-National Survey Data Sets: Health and Society in East Asia, 2010 (n=7938; China, n=3866; Japan, n=2496; South Korea, n=1576). South Koreans perceived environmental pollution to be the most severe, while Japanese participants perceived environmental pollution to be the least severe. Although the Japanese did not perceive environmental pollution to be very severe, their self-rated physical health was significantly related to perceived environmental pollution, while the analogous relationships were not significant for the Chinese or Korean participants. Better mental health was related to lower levels of perceived air pollution in China, as well as lower levels of perceived all types of pollution in Japan and lower levels of perceived noise pollution in South Korea. Physical and mental health and individual socio-demographic characteristics were associated with levels of perceived environmental pollution, but with different patterns among these three countries.

Perceived Environmental Pollution and Its Impact on Health in China, Japan, and South Korea

PubMed Central

2017-01-01

Objectives Environmental pollution is a significant global issue. Both objective (scientifically measured) environmental pollution and perceived levels of pollution are important predictors of self-reported health. The purpose of this study was to compare the associations between perceived environmental pollution and health in China, Japan, and South Korea. Methods Data were obtained from the East Asian Social Survey and the Cross-National Survey Data Sets: Health and Society in East Asia, 2010 (n=7938; China, n=3866; Japan, n=2496; South Korea, n=1576). Results South Koreans perceived environmental pollution to be the most severe, while Japanese participants perceived environmental pollution to be the least severe. Although the Japanese did not perceive environmental pollution to be very severe, their self-rated physical health was significantly related to perceived environmental pollution, while the analogous relationships were not significant for the Chinese or Korean participants. Better mental health was related to lower levels of perceived air pollution in China, as well as lower levels of perceived all types of pollution in Japan and lower levels of perceived noise pollution in South Korea. Conclusions Physical and mental health and individual socio-demographic characteristics were associated with levels of perceived environmental pollution, but with different patterns among these three countries. PMID:28605887

Ethnobotanical Knowledge Is Vastly Under-Documented in Northwestern South America

PubMed Central

Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik; Macía, Manuel J.

2014-01-01

A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes. PMID:24416449

Walking a Tightrope: Vietnam’s Security Challenge in the South China Sea and Implications for U.S. PACOM

DTIC Science & Technology

2013-11-01

Islands and back up to Taiwan . In the words of analyst Robert Kaplan, “geography propels China forward into the South China Sea.” 3 The bilateral...vigorously began to defend its historical claims to the Paracels and Spratlys, with the Philippines, Malaysia, Taiwan , and Brunei also laying claim to the...approach. 4 Background on the South China Sea dispute provided in Patrick M. Cronin, Peter A. Dutton

Open Ocean Internal Waves, South China Sea

NASA Technical Reports Server (NTRS)

1989-01-01

These open ocean internal waves were seen in the south China Sea (19.5N, 114.5E). These sets of internal waves most likely coincide with tidal periods about 12 hours apart. The wave length (distance from crest to crest) varies between 1.5 and 5.0 miles and the crest lengths stretch across and beyond this photo for over 75 miles. At lower right, the surface waves are moving at a 30% angle to the internal waves, with parallel low level clouds.

Spatial distribution of an ancient agricultural oasis in Juyan, northwestern China

NASA Astrophysics Data System (ADS)

Hu, Ningke; Li, Xin

2014-09-01

Activities related to agricultural cultivation are some of the major human drivers of landscape change on the Earth's surface. Archaeological remains can provide qualitative evidence for studies of past agricultural development and environmental conditions. The ancient Juyan Oasis, which once flourished along the historic Silk Road, was a typical oasis of downstream inland river basins in the arid zone of northwestern China. Historical records and archaeological discoveries have qualitatively shown that the oasis supported extensive agricultural activities in this historical period from the Han Dynasty to the early Ming Dynasty (B.C. 202-A.D. 1375), which can be traced back to 2,000 years ago. In this study, different types of archaeological remains (including archaeological sites, ground surface artifacts, ancient cultivation ruins, and agricultural irrigation canals) that were obtained and identified from previous archaeological reports, field inspections, and remote sensing imagery were used to determine the spatial extent of the agricultural oasis in the historical period of interest. Our approach used multiple data sources in order to increase the accuracy and reliability of the results compared to previous studies. Our results distinctly suggested that much of the oasis was cultivated during the historical periods considered. Additionally, the arable land area in the historical period considered was roughly estimated to be approximately (3.39-4.75) × 104 ha. These findings regarding the spatial distribution of this ancient agricultural oasis and its arable land were reasonably determined to represent the ancient agricultural development that occurred in the Juyan Oasis better than results obtained from single sources of data.

Preventing Escalation in the South China Sea Disputed Waters: A Comparative Study of Republic of the Philippines and Socialist Republic of Vietnam

DTIC Science & Technology

2015-03-01

among claimants’ civilian and military maritime forces in the South China Sea, and there are few studies of how the lack of civil-military cooperation...ESCALATION IN THE SOUTH CHINA SEA DISPUTED WATERS: A COMPARATIVE STUDY OF REPUBLIC OF THE PHILIPPINES AND SOCIALIST REPUBLIC OF VIETNAM by Askari...SOUTH CHINA SEA DISPUTED WATERS: A COMPARATIVE STUDY OF REPUBLIC OF THE PHILIPPINES AND SOCIALIST REPUBUC OF VIETNAM 6. AUTHOR(S) Askari 7

Use of a Survey to Assess the Environmental Exposure and Family Perception to Lead in Children (<6 Years) in Four Valley Cities, Northwestern China

PubMed Central

Sun, Xuemeng; Liu, Dongying; Yang, Tao; Zhao, Yanan; Wu, Ting; Cai, Yue; Ai, Yuwei; Zhang, Xu; Wang, Jiwen; Yang, Rui; Yu, Hongtao

2018-01-01

With the growth of industry, the extensive use of lead, and urban expansion in Northwestern Valley Cities (NVC) China, there is probable reason for presuming an increasing risk of lead exposure. However, little is known about the lead exposure of children less than 6 years old in NVC. As a first investigation, this study uses a survey to systematically determine the influences of various risk factors within the family environment, parents’ background, children’s behavior, mother’s behavior during pregnancy, and parental perception about children’s blood lead (CBL). A total of 596 families were recruited from the general population in Urumqi, Lanzhou, Xining and Yan’an. Parents, and their children (<6 years old), were asked about the environment and behaviors which could possibly relate with lead exposure. The results indicated that in the typical NVC of China, children’s environment and behavior, parents’ education level, and mother’s pregnancy behavior, were associated with potential CBL. It was noted that not all parents in NVC China recognized the importance of children’s lead exposure. Therefore, children’s health care and medical screening campaigns need to be designed to improve family’s fundamental knowledge of lead hazards, associated health effects, and prevention in the NVC of China. PMID:29649165

First detection of Candidatus Rickettsia barbariae in the flea Vermipsylla alakurt from north-western China.

PubMed

Zhao, Shan-Shan; Li, Hong-Yu; Yin, Xiao-Ping; Liu, Zhi-Qiang; Chen, Chuang-Fu; Wang, Yuan-Zhi

2016-06-07

Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Vermipsylla alakurt is mainly distributed in alpine pastoral areas of Kazakhstan, Mongolia, China and Nepal, and infests sheep, yaks and horses, causing irritation, poor condition, anaemia and even death. However, to date, no rickettsial agents have been reported in V. alakurt. A total of 133 fleas were collected directly from the tails of three sheep flocks (n = 335) in Minfeng County, Xinjiang Uygur Autonomous Region, north-western China. Of these, 55 fleas were identified by morphological examination and molecular analysis of four loci (the ribosomal 18S and 28S rDNA genes and the mitochondrial genes cytochrome  c oxidase subunit II and elongation factor 1-alpha). Eight Rickettsia-specific gene fragments originated from seven genes: the 17-kilodalton antigen gene (17-kDa), citrate synthase gene (gltA), 16S rRNA gene (rrs), outer membrane protein A gene (ompA), surface cell antigen 1 gene (sca1), PS120 protein gene (gene D), and outer membrane protein B gene (ompB, two fragments), were used to identify the species of Rickettsia in 53 fleas. The amplified products were sequenced and included in a phylogenetic analysis to verify the taxonomic identification of the rickettsial agents. Based on morphological and molecular evidence, the flea was identified as Vermipsylla alakurt. Nine samples were positive (16.98 %, 9/53) for Rickettsia spp. The phylogenetic tree revealed that the rickettsial agents found in V. alakurt cluster with Candidatus Rickettsia barbariae. Our study suggests that: (i) V. alakurt may serve as a carrier for Candidatus R. barbariae; and (ii) Candidatus R. barbariae, previously reported in Israel, is the eighth newly discovered validated Rickettsia species in China. This finding extends our knowledge of the distribution of Candidatus R. barbariae and the profile of carriers, which not only comprise ticks but also fleas.

Sea Surface Temperature and Ocean Color Variability in the South China Sea

NASA Astrophysics Data System (ADS)

Conaty, A. P.

2001-12-01

The South China Sea is a marginal sea in the Southeast Asian region whose surface circulation is driven by monsoons and whose surface currents have complex seasonal patterns. Its rich natural resources and strategic location have made its small islands areas of political dispute among the neighboring nations. This study aims to show the seasonal and interannual variability of sea surface temperature and ocean color in South China Sea. It makes use of NOAA's Advanced Very High Resolution Radiometer (AVHRR) satellite data sets on sea surface temperature for the period 1981-2000 and NASA's Nimbus-7 Coastal Zone Color Scanner (CZCS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite data sets on pigment concentration (ocean color) for the period 1981-1996 and 1997-2000, respectively. Transect lines were drawn along several potential hotspot areas to show the variability in sea surface temperature and pigment concentration through time. In-situ data on sea surface temperature along South China Sea were likewise plotted to see the variability with time. Higher seasonal variability in sea surface temperature was seen at higher latitudes. Interannual variability was within 1-3 Kelvin. In most areas, pigment concentration was higher during northern hemisphere winter and autumn, after the monsoon rains, with a maximum of 30 milligrams per cubic meter.

Population genetics of Thamnaconus hypargyreus (Tetraodontiformes: Monacanthidae) in the South China Sea.

PubMed

Li, Yufang; Chen, Guobao; Yu, Jie; Wu, Shuiqing; Xiong, Dan; Li, Xia; Cui, Ke; Li, Yongzhen

2016-01-01

Knowledge of population structure is particularly important for long-term fisheries management and conservation. Lesser-spotted leatherjacket Thamnaconus hypargyreus is an economically important fish species in the South China Sea. Fish specimens (totally 158 individuals) used in this study were collected from five geographical locations in the north of the South China Sea and the southwestern Nansha Islands. The results were as follows: a total of 636 nucleotides of the mitochondrial DNA (mtDNA) control region (CR) of T. hypargyreus were amplified by polymerase chain reaction (PCR) technology. Both 103 mutations of nucleotide acids without inserting or deleting one and 91 haplotypes were found among the examined CR fragment. High haplotype diversity (0.9419 ± 0.0151) and nucleotide diversity (0.0095 ± 0.00506) relatively together with a recent and sudden population expansion which characterizes the genetic population structure of this species. Analysis of molecular variance (AMOVA) and the fixation indices (Fst) of five groups showed that the genetic variance mainly came from individuals within groups, and there was no genetic differentiation between groups. The phylogenetic trees including maximum likelihood (ML) and Bayesian inference (BI) proved no phylogeographic differentiation structure in five groups. The mtDNA marker suggested the five groups should be genetic homogeneity, which implied T. hypargyreus in the north and southwest continental shelf of the South China Sea belongs to one population.

The relationship between the opening of South China Sea and the formation of the Tibetan Plateau (Invited)

NASA Astrophysics Data System (ADS)

Mo, X.

2010-12-01

The South China Sea is one of the largest marginal seas in western Pacific and underwent a complex history. Xu et al.(2004) suggested that the evolution of the South China Sea can be divided into two first order phases: Paleogene (—Early Miocene) rifting and Neogene post- rifting. An oceanic crust was formed during 32-17 Ma. Whether or not the opening of South China Sea were related to Indo-Eurasia collision and the formation of the Tibetan Plateau is one of challenging problem in Earth sciences. With an exception of the southwestern China, the Chinese continent has become an united continent in the Triassic by the Indosinian orogeny. However, the Qinghai-Tibet area in SW China was still an oceanic region, that is, the Neo-Tethys. During the period of 145-100 Ma, the Lhasa terrane collided with the Qiangtang terrane and added to the south margin of the Eurasian continent. On the other hand, the Indian plate subducted underneath the Eurasian continent since Jurassic- Cretaceous. Subsequently, collision between the two continents, India and Eurasia, were completed during 65-40 Ma, and went into a post-collisional stage, characterized by intra-continental movements, including intra-continental subduction, overthrust, strike-slip and so on. The Tibetan Plateau, the highest plateau in the world had been formed by multi-stage uplifts. Several huge strike-slip shear zone such as the Red River Fault and the Altyn were formed during that period. The >1000-km-long Oligocene—Miocene left-lateral Red River shear zone (RRSZ) and the Pliocene—active right-lateral Red River fault (RRF), stretching from SE Tibet to the South China Sea, has been cited as a lithospheric scale strike-slip fault. The age of RRSZ was recently determined no earlier than 31.9-24.2Ma and no later than 21.7 Ma (Searle et al., 2010). Many geologists believe that there possibly be close relationship between the opening of the South China Sea and Indo-Eurasia collision and the formation of the Tibetan

Fertile lithospheric mantle beneath the northwestern North China and its implication for the subduction of the Paleo-Asian Ocean

NASA Astrophysics Data System (ADS)

Dai, H. K.; Zheng, J.; Su, Y. P.; Xiong, Q.; Pan, S. K.

2017-12-01

The nature of the sub-continental lithospheric mantle (SCLM) beneath the western North China Craton (NCC) is poorly known, which hinders understanding the cratonic response to the southward subduction of the Paleo-Asian Ocean. Mineral chemical data of spinel lherzolite xenoliths from newly discovered Cenozoic Langshan basalts in the northwestern part of the craton have been integrated with data from other localities across the western NCC, to put constrains on the SCLM nature and to explore the reworking processes involved. Compositions of mineral cores (i.e., Mg# in olivine = 88 91) and P-T estimates ( 1.2 GPa, 950 oC) suggest the Langshan xenoliths/xenocrysts represent fragments of the uppermost SCLM and experienced <15% melt extraction. These characteristics are similar to those of mantle xenoliths from other locaties (Siziwangqi and Hannuoba) along the northern margin of the western NCC. Disequilibrium characteristics are observed in xenoliths/xenocrysts in this study, including pyroxene spongy coronae and compositionally zoned olivine. They are interpreted to be induced by partial melting and by ironic diffusion with silicate melts in the mantle respectively, shortly before the eruption of host basalt. Metasomatism is recorded in clinopyroxene cores by concomitant enrichments in light rare earth elements and high field strength elements and was likely related to the migration of silicate melts derived from a mantle modified by slab melts during the Paleozoic time. The SCLM along the northern margin of the western NCC is fertile in nature constrained by mantle xenoliths from several localities (Langshan in this study, Siziwangqi and Hannuoba in references). Considering 1) the coexistence of fertile lithospheric mantle (similar to the Phanerozoic SCLM of the eastern NCC) and the overlying ancient continental crust, and 2) the sharp decrease in lithospheric thickness from the inner part to the northern margin of the western NCC, the SCLM beneath the northwestern

Modeling and Prediction of Internal Waves in the South China Sea

DTIC Science & Technology

2011-12-01

Islands Soliton Experiment), while VANS (Variability Around the Northern South China Sea) involved researchers from Taiwan. In addition to...troughs. These rough/smooth regions are distinctive features in satellite Imagery of the sea surface and appear as bands of light and dark

High resolution 3-D shear wave velocity structure in South China from surface wave tomography

NASA Astrophysics Data System (ADS)

Ning, S.; Guo, Z.; Chen, Y. J.

2017-12-01

Using continuous data from a total of 638 seismic stations, including 484 from CEArray between 2008 and 2013 and 154 from SINOPROBE between 2014 and 2015, we perform both ambient noise and earthquake Rayleigh wave tomography across South China. Combining Rayleigh wave phase velocity between 6and 40s periods from ambient noise tomography and Rayleigh wave phase velocity between 20and 140s from teleseismic two-plane-wave tomography, we obtain phase velocity maps between 6 and140 s periods. We then invert Rayleigh wave phase velocity to construct a 3-D shear wave velocity structure of South China by Markov Chain Monte Carlo method. Similar to other inversion results, our results correspond topography well. Moreover, our results also reveal that velocity structure of the eastern South China in mantle depth is similar to eastern North China, the core of the western South China, Sichuan Block (SB),still exists thick lithosphere. However, owing to much more data employed and some data quality control techniques in this research, our results reveal more detailed structures. Along Qinling-Dabie Orogenic Belt (QDOB), North-South Gravity Lineament (NSGL) and the Sichuan-Yunnan Rhombic Block (SYRB), there are obvious high speed anomalies in depths of 10-20 km, which possibly imply ancient intrusions. Moreover, it seems that Tancheng-Lujiang Fault Zone (TLFZ) has already cut through QDOB, forming a deep fracture cutting through the crust of the whole China continent. Although SB still exists thick lithosphere, there are indications for thermal erosion. At the same time, the lithosphere of the central SYRB seems to be experiencing delamination process, obviously forming a barrier to prevent the hot Tibetan Plateau (TP) mantle material from flowing further southeast. Upwelling hot mantle material possibly triggered by this delamination process might be the cause of the Emeishan Large Igneous Province. There exists an intercontinental low velocity layer in the crust of the TP

Cenozoic tectonic subsidence in the Southern Continental Margin, South China Sea

NASA Astrophysics Data System (ADS)

Fang, Penggao; Ding, Weiwei; Fang, Yinxia; Zhao, Zhongxian; Feng, Zhibing

2017-06-01

We analyzed two recently acquired multichannel seismic profiles across the Dangerous Grounds and the Reed Bank area in the South China Sea. Reconstruction of the tectonic subsidence shows that the southern continental margin can be divided into three stages with variable subsidence rate. A delay of tectonic subsidence existed in both areas after a break-up, which was likely related to the major mantle convection during seafloor spreading, that was triggered by the secondary mantle convection below the continental margin, in addition to the variation in lithospheric thickness. Meanwhile, the stage with delayed subsidence rate differed along strikes. In the Reed Bank area, this stage is between 32-23.8 Ma, while in the Dangerous Grounds, it was much later (between 19-15.5 Ma). We believe the propagated rifting in the South China Sea dominated the changes of this delayed subsidence rate stage.

Alluvial fan in China

NASA Image and Video Library

2008-09-05

This image captures the beauty of a major alluvial fan in Tsinghai, a province located in Northwestern China. This archival image was taken from NASA Space Shuttle in 1997 as part of its ISS EarthKAM mission.

Crustal Deformation In the Northwestern Margin of the South China Sea: Results From Wide-angle Seismic Modeling

NASA Astrophysics Data System (ADS)

Huang, H.; Klingelhoefer, F.

2017-12-01

The South China Sea (SCS) has undergone episodic spreading during the Cenozoic Era. The long-term extension has shaped the continental margins of the SCS, leading to a progressive breakup of the lithosphere. Separated blocks and rift troughs, as controlled by tectonic stretching, contains key information about the deforming mechanism of the crust. In this work, we present a P-wave velocity model of a wide-angle seismic profile OBS2013-1 which passes through the NW margin of the SCS. Modeling of 25 ocean bottom seismometers (OBS) data revealed a detailed crustal structure and shallow complexities along the profile (Figure 1). The crust thins symmetrically across the Xisha Trough, from more than 20 km on flanks to 10 km in the central valley where the sediments thickens over 5 km; A volcano is situated on top of the centre basement high where the Moho drops slightly. At the distal margin around the Zhongsha Trough, the upper crust was detached and accordingly made the middle crust exhumed in a narrow area ( 20 km wide). Meanwhile, materials from the lower crust rises asymmetrically, increasing the crustal velocity by 0.3 km/s and may also giving rise to volcanisms along the hanging side. A 40 km wide hyper-stretched crust (with thickness of 5 km) was identified next to the Zhongsha Trough and covered by overflowing magma and post-rift sediments on the top. These observations argue for a depth-related and asymmetrically extension of the crust, including (1) detachment fault controls the deformation of the upper crust, leading to exhumation of the middle crust and asymmetrically rising of the lower crust, (2) The region adjacent to the exhumation region and with highly thinned crust can be considered as extinct OCT due to magma-starved supplying.

Personal exposure of PM2.5 emitted from solid fuels combustion for household heating and cooking in rural Guanzhong Plain, northwestern China

NASA Astrophysics Data System (ADS)

Xu, Hongmei; Li, Yaqi; Guinot, Benjamin; Wang, Jinhui; He, Kailai; Ho, Kin Fai; Cao, Junji; Shen, Zhenxing; Sun, Jian; Lei, Yali; Gong, Xuesong; Zhang, Ting

2018-07-01

Household solid fuel combustion for heating and cooking in rural areas is an important source of fine particulate matter (PM2.5) in northwestern China, which largely contributes to PM2.5 personal exposure concentrations during the cold winter. There is a general lack of understanding about the personal exposure to PM2.5 and to its chemical components emitted from domestic solid fuel combustion in northwestern Chinese rural populations. In this work, personal exposure to PM2.5 was sampled using a portative device together with fixed indoor and outdoor fixed samplings in Guanzhong Plain in December 2016 for the purpose of characterizing personal exposure to PM2.5 as a function of different solid fuels used in rural households. The average housewife's personal exposure to PM2.5 concentration was 263.4 ± 105.8 μg m-3 (1σ, n = 30), which was about 40% higher than the values found indoors (186.5 ± 79.5 μg m-3, 1σ, n = 30) and outdoors (191.0 ± 85.3 μg m-3, 1σ, n = 30). High personal exposure PM2.5 levels were mainly related to the ignition of solid fuels for heating and cooking. Correlations among personal exposure, indoor and outdoor PM2.5 levels and their mutual ratios were computed to investigate how personal exposure to fine aerosols can be related to microenvironmental PM2.5 levels and to individual activities. The results showed that households using electric power for heating and cooking were characterized by an average personal exposure PM2.5 value of 156.8 ± 36.6 μg m-3 (1σ, n = 6) while personal exposure to PM2.5 in households using solid fuels was twice higher (310.8 ± 90.4 μg m-3, 1σ, n = 24). Solid fuel combustion products and related secondary formed species dominated PM2.5 mass in personal exposure, indoor and outdoor samples. Motor vehicle emission and various dust sources were two other main contributors identified. Our results demonstrated that the use of clean energy could be an effective measure to reduce personal exposure levels of PM2

Simulation of 1986 South China Sea Monsoon with a Regional Climate Model

NASA Technical Reports Server (NTRS)

Tao, W. -K.; Lau, W. K.-M.; Jia, Y.; Juang, H.; Wetzel, P.; Qian, J.; Chen, C.

1999-01-01

A Regional Land-Atmosphere Climate Simulation System (RELACS) project is being developed at NASA Goddard Space Flight Center. One of the major goals of RELACS is to use a regional scale model with improved physical processes and in particular land-related processes, to understand the role of the land surface and its interaction with convection and radiation as well as the water/energy cycles in the IndoChina/South China Sea (SCS) region. The Penn State/NCAR MM5 atmospheric modeling system, a state of the art atmospheric numerical model designed to simulate regional weather and climate, has been successfully coupled to the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. The original MM5 model (without PLACE) includes the option for either a simple slab soil model or a five-layer soil model (MRF) in which the soil moisture availability evolves over time. However, the MM5 soil models do not include the effects of vegetation, and thus important physical processes such as evapotranspiration and interception are precluded. The PLACE model incorporates vegetation type and has been shown in international comparisons to accurately predict evapotranspiration and runoff over a wide variety of land surfaces. The coupling of MM5 and PLACE creates a numerical modeling system with the potential to more realistically simulate atmosphere and land surface processes including land-sea interaction, regional circulations such as monsoons, and flash flood events. In addition, the Penn State/NCAR MM5 atmospheric modeling system has been: (1) coupled to the Goddard Ice Microphysical scheme; (2) coupled to a turbulent kinetic energy (TKE) scheme; (3) modified to ensure cloud budget balance; and (4) incorporated initialization with the Goddard EOS data sets at NASA/Goddard Laboratory for Atmospheres. The improved MM5 with two nested domains (60 and 20 km horizontal resolution) was used to simulate convective activity over IndoChina and the South China Sea

Characterizations of volatile organic compounds (VOCs) from vehicular emissions at roadside environment: The first comprehensive study in Northwestern China

NASA Astrophysics Data System (ADS)

Li, Bowei; Ho, Steven Sai Hang; Xue, Yonggang; Huang, Yu; Wang, Liqin; Cheng, Yan; Dai, Wenting; Zhong, Haobin; Cao, Junji; Lee, Shuncheng

2017-07-01

Vehicular emission (VE) is one of the important anthropogenic sources for ground-level volatile organic compounds (VOCs) in both urban and suburban areas. A first comprehensive campaign was conducted at an urban roadside in Xi'an, China in summer, 2016. A total of 57 VOCs, as known as critical surface ozone (O3) precursors, and other trace gases were measured simultaneously during the sampling period. Iso-pentane, a tracer of gasoline evaporation, was the most abundant VOC in the roadside samples, followed by isobutane and benzene, attributed to the largest composition (∼70%) of gasoline-fueled vehicles on the road. The molar ratio of toluene/benzene (T/B) in our study (0.36) is far lower than the range reported in other cities, indicating the stronger contributions from diesel emissions. The results of source apportionment achieved with positive matrix factorization (PMF) receptor model were highly consistent with the vehicles compositions, strongly evidenced that the precise characterization of the VE sources from those marker species. The degrees of individual compound contributed to O3 production were weighed by ozone formation potential (OFP). Propylene (20%), 1-butene (11%) and iso-pentane(10%) were the top three contributors at the roadside. The information of this study complements the VOCs database regarding to the VE sources in Northwestern China.

Ecohydrological factors affecting nitrate concentrations in a phreatic desert aquifer in northwestern China

USGS Publications Warehouse

Gates, J.B.; Böhlke, J.K.; Edmunds, W.M.

2008-01-01

Aerobic conditions in desert aquifers commonly allow high nitrate (NO 3-) concentrations in recharge to persist for long periods of time, an important consideration for N-cycling and water quality. In this study, stable isotopes of NO3- (??15N NO3 and ??18ONO3) were used to trace NO3- cycling processes which affect concentrations in groundwater and unsaturated zone moisture in the arid Badain Jaran Oesert in northwestern China. Most groundwater NO3- appears to be depleted relative to Cl- in rainfall concentrated by evapotranspiration, indicating net N losses. Unsaturated zone NO 3- is generally higher than groundwater NO 3- in terms of both concentration (up to 15 476 ??M, corresponding to 3.6 mg NO3--N per kg sediment) and ratios with Cl-. Isotopic data indicate that the NO3- derives primarily from nitrification, with a minor direct contribution of atmospheric NO3- inferred for some samples, particularly in the unsaturated zone. Localized denitrification in the saturated zone is suggested by isotopic and geochemical indicators in some areas. Anthropogenic inputs appear to be minimal, and variability is attributed to environmental factors. In comparison to other arid regions, the sparseness of vegetation in the study area appears to play an important role in moderating unsaturated zone NO3- accumulation by allowing solute flushing and deterring extensive N2 fixation. ?? 2008 American Chemical Society.

Correlations between environmental factors and wild bee behavior on alfalfa (Medicago sativa) in northwestern China.

PubMed

Wang, Xiaojuan; Liu, Hongping; Li, Xiaoxia; Song, Yu; Chen, Li; Jin, Liang

2009-10-01

To discover the effect of environmental factors on pollinator visitation to flowering Medicago sativa, several field experiments were designed to examine the diurnal movement patterns of wild bee species in the Hexi Corridor of northwestern China. Our study results showed that Megachile abluta, M. spissula, and Xylocopa valga showed unimodal diurnal foraging behavior, whereas Andrena parvula and Anthophora melanognatha showed bimodal diurnal foraging behavior. Correlation analysis indicated that diurnal foraging activities of pollinators were significantly correlated with environmental factors. Correlations of foraging activities versus environmental factors for M. abluta, M. spissula, and X. valga best fit a linear model, whereas those of A. parvula and A. melanognatha best fit a parallel quadratic model. Results of this study indicated that solitary wild bees such as M. abluta, M. spissula, X. valga, A. parvula, and A. melanognatha are potential alfalfa pollinators in the Hexi Corridor. An understanding of the environmental factors that affect the behaviors of different wild bees foraging in alfalfa are basic to the utilization of solitary wild bees in a practical way for increased, or more consistent, pollination of alfalfa for seed production.

Climate-driven speedup of alpine treeline forest growth in the Tianshan Mountains, Northwestern China.

PubMed

Qi, Zhaohuan; Liu, Hongyan; Wu, Xiuchen; Hao, Qian

2015-02-01

Forest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration of Picea schrenkiana forest growth since 1960s in the ATE of Tianshan Mountains, northwestern China by a stand-total sampling along six altitudinal transects with three plots in each transect: one from the ATE between the treeline and the forest line, and the other two from the CFB. All the sampled P. schrenkiana forest patches show a higher growth speed after 1960 and, comparatively, forest growth in the CFB has sped up much slower than that in the ATE. The speedup of forest growth at the ATE is mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition within the CFB might have restricted forest growth there more than that within the ATE, implying biotic factors were also significant for the accelerated forest growth in the ATE, which should be excluded from simulations and predictions of warming-induced treeline dynamics. © 2014 John Wiley & Sons Ltd.

Distribution profiles of per- and poly fluoroalkyl substances (PFASs) and their re-regulation by ocean currents in the East and South China Sea.

PubMed

Zheng, Hongyuan; Wang, Feng; Zhao, Zhen; Ma, Yuxin; Yang, Haizhen; Lu, Zhibo; Cai, Minggang; Cai, Minghong

2017-12-15

We investigated the distribution of 17 individual per- and polyfluoroalkyl substances (PFASs) in 42 surface water samples collected from the East and South China Seas (7.0-36.0°N, 110.0°N-123.0°E). Concentrations of 7 individual PFASs, including perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluoropentanoic acid (PFPA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonamide (FOSA), were quantified in the East China Sea, but only concentrations of PFOA and FOSA were quantified in the South China Sea. The total concentrations of the 17 PFASs ranged from 181 to 2658pg/L in the East China Sea and from 62 to 494pg/L in the South China Sea. We also show that river fluxes and ocean currents had a strong influence on the distribution of PFASs in the East China Sea. Using ArcGIS 10.1, we show how ocean currents control the spatial distribution of PFOA in the central South China Sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Petrogenesis of early Jurassic basalts in southern Jiangxi Province, South China: Implications for the thermal state of the Mesozoic mantle beneath South China

NASA Astrophysics Data System (ADS)

Cen, Tao; Li, Wu-xian; Wang, Xuan-ce; Pang, Chong-jin; Li, Zheng-xiang; Xing, Guang-fu; Zhao, Xi-lin; Tao, Jihua

2016-07-01

Early Jurassic bimodal volcanic and intrusive rocks in southern South China show distinct associations and distribution patterns in comparison with those of the Middle Jurassic and Cretaceous rocks in the area. It is widely accepted that these rocks formed in an extensional setting, although the timing of the onset and the tectonic driver for extension are debated. Here, we present systematic LA-ICP-MS zircon U-Pb ages, whole-rock geochemistry and Sr-Nd isotope data for bimodal volcanic rocks from the Changpu Formation in the Changpu-Baimianshi and Dongkeng-Linjiang basins in southern Jiangxi Province, South China. Zircon U-Pb ages indicate that the bimodal volcanic rocks erupted at ca. 190 Ma, contemporaneous with the Fankeng basalts ( 183 Ma). A compilation of geochronological results demonstrates that basin-scale basaltic eruptions occurred during the Early Jurassic within a relatively short interval (< 5 Ma). These Early Jurassic basalts have tholeiitic compositions and OIB-like trace element distribution patterns. Geochemical analyses show that the basalts were derived from depleted asthenospheric mantle, dominated by a volatile-free peridotite source. The calculated primary melt compositions suggest that the basalts formed at 1.9-2.1 GPa, with melting temperatures of 1378 °C-1405 °C and a mantle potential temperature (TP) ranging from 1383 °C to 1407 °C. The temperature range is somewhat hotter than normal mid-ocean-basalt (MORB) mantle but similar to an intra-plate continental mantle setting, such as the Basin and Range Province in western North America. This study provides an important constraint on the Early Jurassic mantle thermal state beneath South China. Reference: Raczek, I., Stoll, B., Hofmann, A.W., Jochum, K.P. 2001. High-precision trace element data for the USGS reference materials BCR-1, BCR-2, BHVO-1, BHVO-2, AGV-1, AGV-2, DTS-1, DTS-2, GSP-1 and GSP-2 by ID-TIMS and MIC-SSMS. Geostandards Newsletter 25(1), 77-86.

Regional Consortia for E-Resources: A Case Study of Deals in the South China Region

ERIC Educational Resources Information Center

Chunrong, Luo; Jingfen, Wang; Zhinong, Zhou

2010-01-01

Purpose: The purpose of this paper is to analyse the current situation and the social and economic benefits from the consortia acquisitions of electronic resources by the China Academic Library and Information System (CALIS) South China Regional Centre and to recommend improvements for consortia acquisitions. Design/methodology/approach: Analyses…

Molecular Approach to the Identification of Fish in the South China Sea

PubMed Central

Zhang, Junbin; Hanner, Robert

2012-01-01

Background DNA barcoding is one means of establishing a rapid, accurate, and cost-effective system for the identification of species. It involves the use of short, standard gene targets to create sequence profiles of known species against sequences of unknowns that can be matched and subsequently identified. The Fish Barcode of Life (FISH-BOL) campaign has the primary goal of gathering DNA barcode records for all the world's fish species. As a contribution to FISH-BOL, we examined the degree to which DNA barcoding can discriminate marine fishes from the South China Sea. Methodology/Principal Findings DNA barcodes of cytochrome oxidase subunit I (COI) were characterized using 1336 specimens that belong to 242 species fishes from the South China Sea. All specimen provenance data (including digital specimen images and geospatial coordinates of collection localities) and collateral sequence information were assembled using Barcode of Life Data System (BOLD; www.barcodinglife.org). Small intraspecific and large interspecific differences create distinct genetic boundaries among most species. In addition, the efficiency of two mitochondrial genes, 16S rRNA (16S) and cytochrome b (cytb), and one nuclear ribosomal gene, 18S rRNA (18S), was also evaluated for a few select groups of species. Conclusions/Significance The present study provides evidence for the effectiveness of DNA barcoding as a tool for monitoring marine biodiversity. Open access data of fishes from the South China Sea can benefit relative applications in ecology and taxonomy. PMID:22363454

Foreign trade and pollution: the case of South China water quality

NASA Astrophysics Data System (ADS)

Zuo, Hui; Ai, Danxiang; Lin, Yuling

2017-01-01

With rapid economic growth, South China has to face the most serious water pollution. However, whether or not such kind of water pollution is mainly caused by foreign trade is questionable. And, how the trade mode will be changed by pollution and corresponding regulation is also uncertain. In this paper, a fully endogenous model, which integrate economic growth, energy use and pollution, is designed to interpret the interrelation among these key variables in South China. Through this model, a new possibility of water environment Kuznets curve change has been investigated. Attribute to mixed two stage feasible general least square estimation method, we conclude that foreign trade has strong influence on environment change rate and the turning point. It can make the virtuous circle of between economic growth and environment improvement come early or later in different circumstances. Export and import play different role in such process and have counter effects on environment.

The South China - Indochina collision: a perspective from sedimentary basins analysis

NASA Astrophysics Data System (ADS)

Rossignol, Camille; Bourquin, Sylvie; Hallot, Erwan; Poujol, Marc; Roger, Françoise; Dabard, Marie-Pierre; Martini, Rossana; Villeneuve, Michel; Cornée, Jean-Jacques; Peyrotty, Giovan

2017-04-01

Sedimentary basins, through the sedimentary successions and the nature of the deposits, reflect the geology of the area from which the sediments were derived and thus provide valuable record of hinterland tectonism. As the collision between the South China and the Indochina blocks (i.e., the Indosinian orogeny) is still the object of a number of controversies regarding, for instance, its timing and the polarity of the subduction, the sedimentary basins associated with this mountain belt are likely to provide clues to reconstruct its geodynamic evolution. However, both the Sam Nua Basin (located to the south of the inner zones of the Indosinian orogeny and the Song Ma ophiolites) and the Song Da Basin (located to the north of the inner zones), northern Vietnam, are still lacking important information regarding the depositional environments and the ages of the main formations that they contain. Using sedimentological and dating analyses (foraminifers biostratigraphy and U-Pb dating on detrital zircon), we provide a new stratigraphic framework for these basins and propose a geodynamic evolution of the present-day northern Vietnam. During the Early Triassic, the Sam Nua Basin was mainly supplied by volcaniclastic sediments originating from an active volcanic activity. Geochemical investigations, combined with sedimentological and structural analyses, support an arc-related setting for this magmatism. This magmatic arc resulted from the subduction of a south dipping oceanic slab that once separated the South China from the Indochina blocks. During the Middle to the Late Triassic, the Sam Nua Basin underwent erosion that lead to the formation of a major unconformity, termed the Indosinian unconformity. This unconformity is interpreted to result from the erosion of the Indosinian mountain belt, built after the continental collision between the South China and the Indochina blocks. Later, during the Late Triassic, the Sam Nua Basin experienced the deposition of very coarse

Prevalence, risk factors and impact of gastroesophageal reflux disease symptoms: a population-based study in South China.

PubMed

Chen, Minhu; Xiong, Lishou; Chen, Huixin; Xu, Angao; He, Longjun; Hu, Pinjin

2005-07-01

There are few data on the epidemiology of gastroesophageal reflux disease (GERD) in South China. The aim of this study was to assess the prevalence of GERD symptoms in South China and to evaluate the impact on health-related quality of life. A face-to-face interview was carried out in South China using a validated Chinese version of the Reflux Disease Questionnaire to assess the prevalence of GERD symptoms. A randomly clustered sampling of permanent inhabitants aged 18 to 90 years was carried out under stratification of urban and suburban areas. The impact of GERD symptoms on health-related quality of life was evaluated using the Chinese version of SF-36. A total of 3338 residents (1468 M, 1870 F) were investigated. Mean age of the responders was 42.6 +/- 16.4 years; response rate was 95%. The prevalence of heartburn and/or acid eructation occurring at least weekly was 6.2%. The age- and gender-adjusted point prevalence of GERD symptoms in South China is 2.3% (95% CI, 1.8%, 2.8%) according to the definition in this study. There was no difference in prevalence between male (2.6%) and female (2.4%) subjects and there was no significant association between age and prevalence of GERD symptoms. Divorced/widowed/separated subjects (OR 4.61; 95% CI, 2.15%, 9.89%) and subjects with a heavy burden of work (OR 3.43, 95% CI, 1.72%, 6.84%) were significantly more likely to report GERD symptoms. As compared with the general population, subjects with GERD symptoms experienced considerable impairment in quality of life. The prevalence of GERD symptoms in South China was much lower than that reported in Western countries. GERD had a negative impact on quality of life.

Geodynamics of the South China Sea

NASA Astrophysics Data System (ADS)

Sibuet, Jean-Claude; Yeh, Yi-Ching; Lee, Chao-Shing

2016-12-01

The beginning of seafloor spreading in the South China Sea (SCS) is now established from IODP drilling Leg 349 at 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17-22 Ma ago. Based on magnetic anomaly identifications, the end of the SCS spreading could be either 15.5, 20.5 Ma (Briais et al., 1993; Barckhausen et al., 2014) or something else. However, as post-spreading magmatic activity ( 13-3.5 Ma) largely masks the spreading fabric in particular near the axis of the east sub-basin, published locations of the axial magnetic anomaly (extinct spreading axis) and spreading rates are not reliable. A contoured map of the extremely dense set of magnetic data shows that a few magnetic lineations belonging to the magnetic seafloor spreading fabric are still preserved and parallel to the N055° bathymetric seafloor spreading trends identified on swath-bathymetric maps in the central part of the SCS, suggesting that the extinct ridge axis is N055° trending with potential N145° transform faults. Based on published swath-bathymetric data, oceanic domains with different seafloor spreading lineaments have been delimited (N055°, N075° and N085°) and provide important constraints used to propose a kinematic sketch of the SCS opening. As a consequence, the Zhongnan faults zone, located between the east and southeast sub-basins, acted as a major fracture zone system during the SCS opening, with horizontal offsets varying from 50 km to 140 km. The flow-line pattern defined from the seafloor spreading lineaments and the few identified FZs have been used to highlight conjugate segments of continental margins. During the first phases of opening of the SCS, from the fit of continents to chron C10 (30 Ma), the N175° extension observed

Regional heatwaves in china: a cluster analysis

NASA Astrophysics Data System (ADS)

Wang, Pinya; Tang, Jianping; Wang, Shuyu; Dong, Xinning; Fang, Juan

2018-03-01

With the consideration of spatial extension of heatwave events, two kind of regional heatwaves using absolute and relative thresholds, namely RHWs-A and RHWs-R, are investigated during 1959-2013. The temperature data is derived from the daily maximum temperatures (DMTs) of 587 stations in China. Totally 298 RHWs-A and 374 RHWs-R are identified during the past 55 years, and both of them are growing more frequent since the mid-1980s. By utilizing the cluster analysis, several typical spatial distributions of RHWs-A/RHWs-R are obtained. For RHWs-A, there are three clusters covering the southeastern, northwestern China and the lower reaches of Yangtze River, of which the southeastern cluster groups the most heatwaves. For RHWs-R, there are seven clusters distributed throughout the whole regions of China. The clusters in the northwestern and northeastern China are more stable than others for both RHWs-A and RHWs-R, and the northern clusters are of larger intensity than that of the southern ones. All RHWs-A/RHWs-R are accompanied by the anomalous high systems along with the reduced soil moisture. The southern clusters are controlled by Northwestern Pacific subtropical high (WPSH), and the northern ones are influenced by the mid-latitude high systems. The influences of atmospheric circulations and soil moisture on regional heatwaves are further demonstrated by two case analyses of the severe RHW-A in 2003 and the RHW-R in 2013.

Evidence for North-South Long Range Transport of Pollutants Across the South China Sea During the Winter Monsoon

NASA Astrophysics Data System (ADS)

Sturges, W. T.

2015-12-01

A new atmospheric observing station has been established on the east coast of Peninsular Malaysia on the southern seaboard of the South China Sea. During a first intensive campaign in January-February 2014, evidence was observed for substantial elevations in a wide range of greenhouse gases and ozone depleting substances, including CO­2 and CH4 and industrially-derived halocarbons such as HCFCs, HFCs and chlorinated solvents, during "cold surge" conditions at the end of the winter monsoon. Carbon monoxide and ozone were also elevated at such times. Air mass footprints indicated that flow during these events was from eastern China and the Indochina Peninsular. Satellite fire counts indicated that substantial biomass burning was taking place, notably in Vietnam and Cambodia, at this time. As the air mass footprints moved east towards the Western Pacific, mixing ratios of all such gases declined to typical northern hemispheric background conditions. These findings are of note both as a clear indication of the long-range transport of a mixture of biomass burning products and industrial emissions over thousands of kilometres across the South China Sea, and also because such transported pollutants may be subject to rapid vertical transport to the upper troposphere and lower stratosphere by tropical deep convection.

Isolation and Characterization of a Novel Tembusu Virus Circulating in Muscovy Ducks in South China.

PubMed

Yan, Z; Shen, H; Wang, Z; Lin, W; Xie, Q; Bi, Y; Chen, F

2017-10-01

Duck Tembusu virus (DTMUV) is an infectious pathogen that can cause epidemics in egg-laying ducks. Here, we isolated and characterized a DTMUV, designated GDLH01, thought to be responsible for the noticeable egg drop in Muscovy duck flocks in South China since 2011. The genome sequence of GDLH01 shared 97-99% homology with other avian-origin Tembusu viruses, and 99.5% homology with the mosquito-borne strain SDMS recently reported in China. Phylogenetic analysis based on the nucleotide sequence of the entire open reading frame confirmed that the isolate was of avian origin and closely related to a mosquito-borne strain. Our findings characterize a novel Tembusu virus circulating in Muscovy ducks in South China and emphasize the importance of reinforcing biosecurity measures and developing vaccines to prevent the spread of this viral pathogen. © 2016 Blackwell Verlag GmbH.

The Relationship Between Anomalous Presummer Extreme Rainfall Over South China and Synoptic Disturbances

NASA Astrophysics Data System (ADS)

Huang, Ling; Luo, Yali; Zhang, Da-Lin

2018-04-01

A spectral analysis of daily rainfall data has been performed to investigate extreme rainfall events in south China during the presummer rainy seasons between 1998 and 2015 (excluding 1999, 2006, 2011, and 2014). The results reveal a dominant frequency mode at the synoptic scale with pronounced positive rainfall anomalies. By analyzing the synoptic-scale bandpass-filtered anomalous circulations, 24 extreme rainfall episodes (defined as those with a daily rainfall amount in the top 5%) are categorized into "cyclone" (15) and "trough" (8) types, with the remaining events as an "anticyclone" type, according to the primary anomalous weather system contributing to each extreme rainfall episode. The 15 cyclone-type episodes are further separated into (11) lower- and (4) upper-tropospheric migratory anomalies. An analysis of their anomalous fields shows that both types could be traced back to the generation of cyclonic anomalies downstream of the Tibetan Plateau, except for two episodes of lower-tropospheric migratory anomalies originating over the South China Sea. However, a lower-tropospheric cyclonic anomaly appears during all phases in the former type, but only in the wettest phase in the latter type, with its peak disturbance occurring immediately beneath an upper-level warm anomaly. The production of extreme rainfall in the trough-type episodes is closely related to a deep trough anomaly extending from an intense cyclonic anomaly over north China, which in turn could be traced back to a midlatitude Rossby wave train passing by the Tibetan Plateau. The results have important implications for understanding the origin, structure, and evolution of synoptic disturbances associated with the presummer extreme rainfall in south China.

Assessing South China (Guangzhou) High School Students' Views on Nature of Science: A Validation Study

ERIC Educational Resources Information Center

Deng, Feng; Chai, Ching Sing; Tsai, Chin-Chung; Lin, Tzung-Jin

2014-01-01

Research on students' views on nature of science (VNOS) in Asian countries such as China is notably lacking. This study aimed to develop and validate an instrument to measure South China high school students' VNOS. Based on the previously acquired qualitative data, the instrument included seven VNOS dimensions which reflect the crucial aspects of…

Genetic polymorphisms, forensic efficiency and phylogenetic analysis of 15 autosomal STR loci in the Kazak population of Ili Kazak Autonomous Prefecture, northwestern China.

PubMed

Feng, Chunmei; Wang, Xin; Wang, Xiaolong; Yu, Hao; Zhang, Guohua

2018-03-01

We investigated the frequencies of 15 autosomal STR loci in the Kazak population of the Ili Kazak Autonomous Prefecture with the aim of expanding the available population information in human genetic databases and for forensic DNA analysis. Genetic polymorphisms of 15 autosomal short tandem repeat (STR) loci were analysed in 456 individuals of the Kazak population from Ili Kazakh Autonomous Prefecture, northwestern China. A total of 173 alleles at 15 autosomal STR loci were found; the allele frequencies ranged from 0.5022-0.0011. The combined power of discrimination and exclusion statistics for the 15 STR loci were 0.999 999 999 85 and 0.999 998 800 65, respectively. In addition, phylogenetic analysis involving the Ili Uygur population and other relevant populations was carried out. A neighbour-joining tree and multidimensional scaling plot were generated based on Nei's standard genetic distance. Results of the population comparison indicated that the Ili Uygur population was most closely related genetically to the Uygur populations from other regions in China. These findings are consistent with the historical and geographic backgrounds of these populations.

Persistent halogenated compounds in aquaculture environments of South China: implications for global consumers' health risk via fish consumption.

PubMed

Yu, Huan-Yun; Zhang, Bao-Zhong; Giesy, John P; Zeng, Eddy Y

2011-10-01

This study examined the potential sources of persistent halogenated compounds (PHCs), including organochlorine pesticides, mainly DDXs (sum of o,p'- and p,p'-DDT, -DDD, and -DDE and p,p'-DDMU) and polybrominated diphenyl ethers, to typical aquaculture environments of South China, determined the relative importance of gill diffusion and fish feeding for exposure of fish to these contaminants and assessed potential health risk for global consumers via consumption of fish from South China. Fish feed is generally a direct and important source of PHCs in both freshwater and seawater aquaculture. In addition, gill diffusion is the predominant uptake route for PHCs (except p,p'-DDMU, o,p'-DDD and -DDT) in farmed freshwater fish, whereas accumulation from the diet is the major route for farmed marine fish. Risks to health of global consumers via consumption of fish from South China are minimal. However, increased risk can be foreseen due to continuous use of brominated fire retardants and electronic waste importation to China. Copyright © 2011 Elsevier Ltd. All rights reserved.

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in coastal waters of northern South China Sea.

PubMed

Wang, Xuefeng; Wang, Lifei; Jia, Xiaoping; Jackson, Donald A

2017-09-01

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in the coastal waters of northern South China Sea were investigated in order to help improve the quality and safety control and sustainable aquaculture for mollusks in China. Cultured oysters (Crassostrea rivularis) collected from the waters of 23 bays, harbors, and estuaries along the coast of northern South China Sea from 1989 to 2012 were examined for spatial patterns and long-term temporal trends of oyster arsenic levels. Single-factor index and health risk assessment were used to quantify arsenic exposure to human health through oyster consumption. Overall, arsenic was detected in 97.4% of the oyster samples, and oyster arsenic levels were non-detectable-2.51 mg/kg with an average of 0.63 ± 0.54 mg/kg. Oyster arsenic levels in the coastal waters of northern South China Sea showed an overall decline from 1989 to 2012, remained relatively low since 2005, and slightly increased after 2007. Oyster arsenic levels in Guangdong coastal waters were much higher with more variation than in Guangxi and Hainan coastal waters, and the long-term trends of oyster arsenic levels in Guangdong coastal waters dominated the overall trends of oyster arsenic levels in the coastal waters of northern South China Sea. Within Guangdong Province, oyster arsenic levels were highest in east Guangdong coastal waters, followed by the Pearl River estuary and west Guangdong coastal waters. Single-factor index ranged between 0.27 and 0.97, and average health risk coefficient was 3.85 × 10 -5 , both suggesting that oyster arsenic levels in northern South China Sea are within the safe range for human consumption. However, long-term attention should be given to seafood market monitoring in China and the risk of arsenic exposure to human health through oyster consumption.

Increase in Export Production in the Marginal Seas of the Northwestern Pacific in Response to Anthropogenic N Input

NASA Astrophysics Data System (ADS)

Lee, K.; Ko, Y. H.; Moon, J. Y.

2017-12-01

The relative abundance of nitrate (N) over phosphorus (P) has increased significantly over the period since 1980 in the marginal seas (Yellow, East China and East seas) bordering the northwestern Pacific Ocean, located downstream of the populated and industrialized Asian continent. Analysis of datasets for anthropogenic N input, satellite chlorophyll-a (Chl-a), and seawater nutrient data ( 200,000 data points) reveal that transport of N originating from China has been responsible for enhancements of Chl-a in the marginal seas of the northwestern Pacific Ocean. In particular, the contribution of anthropogenic N to new production in these marginal seas is expected to grow considerably in the coming decades. This anthropogenically driven increase in the N content may potentially lead to a long-term change of these marginal seas from being N-limited to P-limited.

Tectonics and distribution of gold deposits in China - An overview

USGS Publications Warehouse

Zhou, T.; Goldfarb, R.J.; Phillips, G.N.

2002-01-01

present along the northern, southeastern and southern margins of the North China craton, along the southwestern and northwestern margins of the Yangtze craton, in the Tianshan and Altayshan orogenic belts in northern Xinjiang, and throughout the southeastern China fold belt. Gold-placer deposits derived from these primary deposits are concentrated in the northernmost part of northeastern China and along the northerwestern margin of the Yangtze craton. The major provinces with significant gold in porphyry-related copper systems and base metal skarns are present in the Yangtze River area along the northeastern and southeastern margin of the Yangtze craton, in the fold belt in southwestern China, and scattered through northern China. Three-quarters of the Chinese gold-only deposits occur within the North China craton margins. Half are located in the uplifted Precambrian metamorphie rocks and most of the remainder are hosted in the Phanerozoic granitoids that intruded the reworked Precambrian terranes. The abundance of granite-hosted gold contrasts the North China craton with other Precambrian cratons, such as those in Western Australia, central Canada, and Zimbabwe, where gold is mainly hosted in the Archean greenstone belts. This difference may be explained by the multiple episodes of Phanerozoic tectonism along the North China craton margins resulting from the collision of the Angara, North China, and South China cratons, and from subduction of the Izanagi-Pacific oceanic plates underneath the eastern China continent.

Preliminary numerical simulation for shallow strata stability of coral reef in South China Sea

NASA Astrophysics Data System (ADS)

Tang, Qinqin; Zhan, Wenhuan; Zhang, Jinchang

2017-04-01

Coral reefs are the geologic material and special rock and soil, which live in shallow water of the tropic ocean and are formed through biological and geological action. Since infrastructure construction is being increasingly developed on coral reefs during recent years, it is necessary to evaluate the shallow strata stability of coral reefs in the South China Sea. The paper is to study the borehole profiles for shallow strata of coral reefs in the South China Sea, especially in the hydrodynamic marine environment?, and to establish a geological model for numerical simulation with Geo-Studio software. Five drilling holes show a six-layer shallow structure of South China Sea, including filling layer, mid-coarse sand, coral sand gravel, fine sand, limestone debris and reef limestone. The shallow coral reef profile next to lagoon is similar to "layers cake", in which the right side close to the sea is analogous to "block cake". The simulation results show that coral reef stability depends on wave loads and earthquake strength, as well as the physical properties of coral reefs themselves. The safety factor of the outer reef is greater than 10.0 in the static condition, indicating that outer reefs are less affected by the wave and earthquake. However, the safety factor next to lagoon is ranging from 0.1 to 4.9. The main reason for the variations that the strata of coral reefs close to the sea are thick. For example, the thickness of reef limestone is more than 10 m and equivalent to the block. When the thickness of inside strata is less than 10 m, they show weak engineering geological characteristics. These findings can provide useful information for coral reef constructions in future. This work was funded by National Basic Research Program of China (contract: 2013CB956104) and National Natural Science Foundation of China (contract: 41376063).

Enlightenment of Development of Higher Education in South Korea to China

ERIC Educational Resources Information Center

Che, Zhenghong; Che, Zhengmei

2012-01-01

China and South Korea are two neighboring countries and are both developing countries. Furthermore, the modern and contemporary higher education of these two countries originates from the middle and late 19th Century, so there are a lot of similarities between the two countries. However, although the origination period of modern and contemporary…

Artificial neural network modeling of dissolved oxygen in the Heihe River, Northwestern China.

PubMed

Wen, Xiaohu; Fang, Jing; Diao, Meina; Zhang, Chuanqi

2013-05-01

Identification and quantification of dissolved oxygen (DO) profiles of river is one of the primary concerns for water resources managers. In this research, an artificial neural network (ANN) was developed to simulate the DO concentrations in the Heihe River, Northwestern China. A three-layer back-propagation ANN was used with the Bayesian regularization training algorithm. The input variables of the neural network were pH, electrical conductivity, chloride (Cl(-)), calcium (Ca(2+)), total alkalinity, total hardness, nitrate nitrogen (NO3-N), and ammonical nitrogen (NH4-N). The ANN structure with 14 hidden neurons obtained the best selection. By making comparison between the results of the ANN model and the measured data on the basis of correlation coefficient (r) and root mean square error (RMSE), a good model-fitting DO values indicated the effectiveness of neural network model. It is found that the coefficient of correlation (r) values for the training, validation, and test sets were 0.9654, 0.9841, and 0.9680, respectively, and the respective values of RMSE for the training, validation, and test sets were 0.4272, 0.3667, and 0.4570, respectively. Sensitivity analysis was used to determine the influence of input variables on the dependent variable. The most effective inputs were determined as pH, NO3-N, NH4-N, and Ca(2+). Cl(-) was found to be least effective variables on the proposed model. The identified ANN model can be used to simulate the water quality parameters.

Characteristics of microseisms in South China

NASA Astrophysics Data System (ADS)

Xiao, H.; Xue, M.; Pan, M.

2017-12-01

Microseisms are generated by coupling ocean waves and the solid earth, and their main frequencies and sources vary in different regions of the world. We use continuous waveforms from three arrays along the southern coast of China to study the types and sources of microseisms in South China. Using cross-correlation functions and a three-component F-K analysis, we found that the main type of microseisms in this area propagates as surface waves, arriving mainly from the east and southeast. We also found that the surface waves have different characteristics: the Rayleigh waves and Love waves have diverse sources, are frequency dependent and have no obvious seasonal changes. In the 0.2-0.25 Hz frequency band, the Rayleigh and Love waves at the W01, W02 and ST arrays show the influences of common microseisms sources from Taiwan and the Luzon Strait. However, in the 0.27-0.5 Hz frequency band, the energy of the microseisms tends to be governed by the offshore sources near the stations. In addition, the Love waves have broader back azimuths than those of the Rayleigh waves, which may due to the energy transfer between Rayleigh and Love waves in the thick sediment layers.

Transport of terrigenous polycyclic aromatic hydrocarbons affected by the coastal upwelling in the northwestern coast of South China Sea.

PubMed

Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

2017-10-01

Coastal upwelling prevails in the coast of Hainan Island, the northern South China Sea (SCS) during summer. We studied the influences of the upwelling on the horizontal and vertical transport of terrigenous polycyclic aromatic hydrocarbons (PAHs). PAHs in dissolved and suspended particulate phase of water samples were determined in the upper (depth < 1 m) and water column (depth > 10 m). PAH levels decreased sharply from inshore to offshore to open sea. The results showed that terrestrial input was the main source of coastal PAHs. Perylene, an important indicator of land plant-derived PAH, showed the significant correlation with PAHs (p < 0.005). This implied that fluvial transport was the primary pathway of terrigenous PAHs into the coast of northern SCS. Variations of the concentrations, compositions and diagnostic ratios of PAHs, accompanied the partition equilibrium in the water column, could indicate the selective degradation of PAHs by the plankton affected by upwelling. Different from the "traditional" transport pathway of PAHs in the water column (surface enrichment-depth depletion distribution), the upwelling could provide the original driver to elevate the upward diffusion of sediment entrained contaminants towards the intermediate even the upper waters. It could also enhance the outward diffusion of terrigenous PAHs accompanied by the offshore transport of the upper waters. Therefore, the transport pathway of PAHs can be summarized by the coastal upwelling rising PAHs with their subsequent transport offshore and settling in the adjacent open sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Age and Size on Xylem Phenology in Two Conifers of Northwestern China.

PubMed

Zeng, Qiao; Rossi, Sergio; Yang, Bao

2017-01-01

The climatic signals that directly affect the trees can be registered by xylem during its growth. If the timings and duration of xylem formation change, xylogenesis can occur under different environmental conditions and subsequently be subject to different climatic signals. An experimental design was applied in the field to disentangle the effects of age and size on xylem phenology, and it challenges the hypothesis that the timings and dynamics of xylem growth are size-dependent. Intra-annual dynamics of xylem formation were monitored weekly during the growing seasons 2013 and 2014 in Chinese pine ( Pinus tabulaeformis ) and Qilian juniper ( Juniperus przewalskii ) with different sizes and ages in a semi-arid region of northwestern China. Cell differentiation started 3 weeks earlier in 2013 and terminated 1 week later in 2014 in small-young pines than in big-old pines. However, differences in the timings of growth reactivation disappeared when comparing the junipers with different sizes but similar age. Overall, 77 days were required for xylem differentiation to take place, but timings were shorter for older trees, which also exhibited smaller cell production. Results from this study suggest that tree age does play an important role in timings and duration of growth. The effect of age should also be considered to perform reliable responses of trees to climate.

Effects of Age and Size on Xylem Phenology in Two Conifers of Northwestern China

PubMed Central

Zeng, Qiao; Rossi, Sergio; Yang, Bao

2018-01-01

The climatic signals that directly affect the trees can be registered by xylem during its growth. If the timings and duration of xylem formation change, xylogenesis can occur under different environmental conditions and subsequently be subject to different climatic signals. An experimental design was applied in the field to disentangle the effects of age and size on xylem phenology, and it challenges the hypothesis that the timings and dynamics of xylem growth are size-dependent. Intra-annual dynamics of xylem formation were monitored weekly during the growing seasons 2013 and 2014 in Chinese pine (Pinus tabulaeformis) and Qilian juniper (Juniperus przewalskii) with different sizes and ages in a semi-arid region of northwestern China. Cell differentiation started 3 weeks earlier in 2013 and terminated 1 week later in 2014 in small-young pines than in big-old pines. However, differences in the timings of growth reactivation disappeared when comparing the junipers with different sizes but similar age. Overall, 77 days were required for xylem differentiation to take place, but timings were shorter for older trees, which also exhibited smaller cell production. Results from this study suggest that tree age does play an important role in timings and duration of growth. The effect of age should also be considered to perform reliable responses of trees to climate. PMID:29379517

Late Paleozoic SEDEX deposits in South China formed in a carbonate platform at the northern margin of Gondwana

NASA Astrophysics Data System (ADS)

Qiu, Wenhong Johnson; Zhou, Mei-Fu; Liu, Zerui Ray

2018-05-01

SEDEX sulfide deposits hosted in black shale and carbonate are common in the South China Block. The Dajiangping pyrite deposit is the largest of these deposits and is made up of stratiform orebodies hosted in black shales. Sandstone interlayered with stratiform orebodies contains detrital zircon grains with the youngest ages of 429 Ma. Pyrite from the orebodies has a Re-Os isochron age of 389 ± 62 Ma, indicative of formation of the hosting strata and syngenetic pyrite ores in the mid-late Devonian. The hosting strata is a transgression sequence in a passive margin and composed of carbonaceous limestone in the lower part and black shales in the upper part. The ore-hosting black shales have high TOC (total organic carbon), Mo, As, Pb, Zn and Cd, indicating an anoxic-euxinic deep basin origin. The high redox proxies, V/(V + Ni) > 0.6 and V/Cr > 1, and the positive correlations of TOC with Mo and V in black shales are also consistent with an anoxic depositional environment. The Dajiangping deposit is located close to the NE-trending Wuchuan-Sihui fault, which was active during the Devonian. The mid-late Devonian mineralization age and the anoxic-euxinic deep basinal condition of this deposit thus imply that the formation of this deposit was causally linked to hydrothermal fluid exhalation in an anoxic fault-bounded basin that developed in a carbonate platform of the South China Block. The regional distribution of many Devonian, stratiform, carbonaceous sediment-hosted sulfide deposits along the NE-trending fault-bounded basins in South China, similar to the Dajiangping deposit, indicates that these deposits formed at a basin developed in the passive margin setting of the South China Block during the Devonian. This environment was caused by the break-up and northward migration of the South China Block from Gandwana.

Diverse deep-sea fungi from the South China Sea and their antimicrobial activity.

PubMed

Zhang, Xiao-Yong; Zhang, Yun; Xu, Xin-Ya; Qi, Shu-Hua

2013-11-01

We investigated the diversity of fungal communities in nine different deep-sea sediment samples of the South China Sea by culture-dependent methods followed by analysis of fungal internal transcribed spacer (ITS) sequences. Although 14 out of 27 identified species were reported in a previous study, 13 species were isolated from sediments of deep-sea environments for the first report. Moreover, these ITS sequences of six isolates shared 84-92 % similarity with their closest matches in GenBank, which suggested that they might be novel phylotypes of genera Ajellomyces, Podosordaria, Torula, and Xylaria. The antimicrobial activities of these fungal isolates were explored using a double-layer technique. A relatively high proportion (56 %) of fungal isolates exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among four marine pathogenic microbes (Micrococcus luteus, Pseudoaltermonas piscida, Aspergerillus versicolor, and A. sydowii). Out of these antimicrobial fungi, the genera Arthrinium, Aspergillus, and Penicillium exhibited antibacterial and antifungal activities, while genus Aureobasidium displayed only antibacterial activity, and genera Acremonium, Cladosporium, Geomyces, and Phaeosphaeriopsis displayed only antifungal activity. To our knowledge, this is the first report to investigate the diversity and antimicrobial activity of culturable deep-sea-derived fungi in the South China Sea. These results suggest that diverse deep-sea fungi from the South China Sea are a potential source for antibiotics' discovery and further increase the pool of fungi available for natural bioactive product screening.

Luminescence dating of the Zeketai loess section in the Ili Basin, northwestern China: Methodological considerations

NASA Astrophysics Data System (ADS)

Qin, Jintang; Zhou, Liping

2018-04-01

Loess deposits in Xinjiang, northwestern China are ideal archives for past environmental changes in the Westerlies-dominated central Asia. Among previous luminescence dating studies of loess in Xinjiang, few have attempted to systematically investigate the methodological aspects. In this study, we report results of a multiple-procedure luminescence dating of the Zeketai loess section in the Ili Basin, central Xinjiang. Optically stimulated luminescence (OSL) and post-infrared infrared stimulated luminescence (pIRIR) signals were used for quartz and polymineral grains of different sizes. The pIRIR ages obtained with two protocols agree well with each other and constrain the loess deposition between 50 ka and 88 ka. The OSL ages of fine-grained quartz are in stratigraphic order and range from 37 ka to 61 ka, but are ∼30% younger than the pIRIR295 ages of both fine and medium grained polyminerals. Although the causes of the discrepancy between the ages derived from different luminescence dating protocols are still to be understood, we stress that the quartz OSL ages of loess in this region are likely to be underestimated, especially for samples older than 40 ka. The polymineral or potassium feldspar pIRIR signal is recommended for dating loess in the Ili Basin, at least as an internal check.

Rifting and reactivation of a Cretaceous structural belt at the northern margin of the South China Sea

NASA Astrophysics Data System (ADS)

Nanni, Ugo; Pubellier, Manuel; Chan, Lung Sang; Sewell, Roderick J.

2017-04-01

The Tiu Tang Lung Fault, Hong Kong Special Administrative Region - China, is located on the northern stretched continental margin of the South China Sea. Along this fault, Middle Jurassic volcanic rocks of the Tai Mo Shan Formation are tectonically juxtaposed on Lower Cretaceous sedimentary rocks of the Pat Sin Leng Formation. Both extensional detachments and compressional features are observed and various genetic strain configurations are proposed for the Tiu Tang Lung Fault with implications for understanding the dynamics of the pre-South China Sea rifting during the Cretaceous. We have identified tilted bedding planes in the continental deposits of the Pat Sin Leng Formation which can be related to Early Cretaceous syn-extensional deposition. A mid-Cretaceous penetrative top-to-the-south to top-to-the-west shear fabric is also observed and serves as an indicator of the strain pattern. This deformation is expressed by cleavages, schistosity, S/C fabrics, kink-folds, phacoids and stretched pebbles at both a macroscopic and microscopic scale. Cleavages and bedding are generally sub-parallel to the local shear orientation. The whole sedimentary pile is crosscut by Cenozoic N70 and N150 normal faults. These constraints, together with previous fission track, seismic and structural data, allow us to reinterpret the kinematics of this domain during syn-orogenic to syn-extensional periods. The observed top-to-the-south thrusting event is coeval with NE-SW strike-slip sinistral fault movement. Subsequent N-S extension can be correlated with South China Sea rifting from Eocene to Oligocene. These observations reveal a polyphase history associated with continental margin inversion which witnessed localized extension on previous compressional structures.

The systematic change of metamorphism along the Dabie-Sulu-Hongseong-Odesan collision belt between the North and South China blocks

NASA Astrophysics Data System (ADS)

Oh, C. W.

2013-12-01

As a last step of formation of the Pangea supercontinent, the North China block collided with the South China block during Permo-Triassic time forming the Oinling-Dabie-Sulu collision belt which was identified by the finding of ultrahigh- and high-P/T eclogites along the belt. After the Qiling-Dabie-Sulu collision belt was found, the continuation of the collision belt into Korean Peninsula became a hot issue. Although the Imjingang belt in Korean Peninsula was suggested as an extension of the belt, no evidence of collision belt such as eclogite and ophiolite, was found. Whereas recent studies on Korean Peninsula reveal that Triassic eclogite (ca. > 230 Ma) formed in the Hongseong area and Triassic post collision igneous rocks (with ca. 230 Ma intrusion ages) occurred throughout the Gyeonggi Massif locating to the north of the line connecting the Hongseong, Yangpyeong and Odesan areas. These new findings derive the tectonic model in which the Permo-Triassic Qinling-Dabie-Sulu collision belt between the North and South China blocks extends into the Hongseong-Yangpyeong-Odesan collision belt in Korean Peninsula. The belt may be further extended into the late Paleozoic subduction complex in the Yanji belt in North Korea through the Paleozoic subduction complex in the inner part of SW Japan. The collision had started from Korea at ca. 250 Ma and propagated towards China. The collision completed during late Triassic. The metamorphic conditions systematically change along the collision belt; ultrahigh-temperature metamorphism occurred in the Odesan area (at 245-230Ma; 9.0-10.6 kbar, 915-1160°C), high-P/T metamorphism in the Hongseong area (17.0-21.9 kbar, 835-860°C) and ultrahigh-pressure metamorphism in the Dabie and Sulu belts (30-40 kbar, 680-880°C). This systematic increasing peak pressure condition and decreasing peak temperature condition towards west, may be due to the increase in the depth of slab break-off towards west, which might be related to the increase

Using OBS Data to Constrain the Characteristics of Microseisms in South China Sea

NASA Astrophysics Data System (ADS)

Xiao, H.; Xue, M.; Yang, T.; Liu, C.; Hua, Q.; Xia, S.; Huo, D.; Huang, H.; Le, B. M.; Pan, M.; Li, L.

2016-12-01

It has long been recognized that ocean gravity waves can generate microseisms through the coupling with the solid earth. Their generation mechanisms, wave types and propagation have been studied and debated intensively. In this study, we are aiming to study microseisms in South China Sea. We use six OBS data from an OBS array experiment supported by Natural Science Foundation of China, all available land broadband seismic data, and all available global satellite data from May 01, 2012 through August 20, 2012 (UTC). We mainly apply four techniques, i.e., power spectrum density (PSD), correlation, temporal frequency spectrum, and frequency dependent polarization analysis to study microseisms in South China Sea. We found that 1) the energy level of microseisms observed on OBSs are higher than land stations and there is no SF (0.05-0.08Hz) on OBSs; 2) SPDF is predominant on both the DF band (0.1-0.5Hz) as well as the whole band of microseisms (0.05-0.5Hz) for both OBSs and Land stations; 3) DF microseisms are significantly intensified by typhoons; 4) the variations of microseisms correlate well with the variations of nearby significant ocean wave height; 5) LPDF microseisms and SPDF microseisms have different polarization directions at most stations, suggesting they are generated from different source area; 6) the predominant directions of SPDF microseisms are much more scattered than those of LPDF microseisms, probably implying that SPDF microseisms have multiple sources; 7) most of microseisms are probably a mixture of P, Love and Rayleigh waves in this region. From our study, we found that the source regions for microseisms observed near marginal seas such as South China Sea are local and do not overlap with the source regions for global microseisms.

Seismic Evidence for a Geosuture between the Yangtze and Cathaysia Blocks, South China

PubMed Central

He, Chuansong; Dong, Shuwen; Santosh, M.; Chen, Xuanhua

2013-01-01

South China, composed of the Yangtze and Cathaysia Blocks and the intervening Jiangnan orogenic belt, has been central to the debate on the tectonic evolution of East Asia. Here we investigate the crustal structure and composition of South China from seismic data employing the H-k stacking technique. Our results show that the composition and seismic structure of the crust in the Jiangnan orogenic belt are identical to those of the Cathaysia Block. Our data reveal a distinct contrast in the crustal structure and composition between the two flanks of the Jiujiang-Shitai buried fault. We propose that the Jiujiang-Shitai buried fault defines a geosuture between the Yangtze and Cathaysia Blocks, and that the felsic lower crust of the Cathaysia Block and the Jiangnan orogenic belt may represent fragments derived from the Gondwana supercontinent. PMID:23857499

Wangshangkia, a new Devonian ostracod genus from Dushan of Guizhou, South China

NASA Astrophysics Data System (ADS)

Song, Junjun; Gong, Yiming

2018-02-01

Wangshangkia, a new genus of Ostracoda, from the Late Devonian in Dushan of Guizhou, South China, is described. This genus belongs to the family Bairdiocyprididae Shaver, 1961 and includes two new species, i.e. Wangshangkia dushaniensis and W. bailouiensis. The new genus is characterized by a wide ventral carina with radial striae. It is reported from the Famennian of South China and disappeared just below the Devonian-Carboniferous boundary. Wangshangkia is essentially a benthic crawler and is restricted to the shallow-marine depositional environment with a low hydrodynamic condition. Wangshangkia: urn:lsid:zoobank.org:act:34BF01D4-D202-492D-8E27-BC508EF7EFFB W. dushaniensis: urn:lsid:zoobank.org:act:D267C362-7510-4D19-996B-EA1848D7D025 W. bailouiensis: urn:lsid:zoobank.org:act:FE988AA0-7363-4D9E-A5AB-1526C8DBCDD9

Role of wind forcing and eddy activity in the intraseasonal variability of the barrier layer in the South China Sea

NASA Astrophysics Data System (ADS)

Liang, Zhanlin; Xie, Qiang; Zeng, Lili; Wang, Dongxiao

2018-03-01

In addition to widely discussed seasonal variability, the barrier layer (BL) of the South China Sea (SCS) also exhibits significant intraseasonal variability (ISV) and plays an important role in the upper heat and salt balances. The characteristics and mechanisms of spatiotemporal variations in the BL are investigated using an eddy-resolving ocean model OFES (OGCM For the Earth Simulator) ouput and related atmospheric and oceanic processes. The active intraseasonal BL variability in the SCS occurs mainly during the late summer/autumn and winter and exhibits remarkable differences between these two periods. The BL ISV in late summer/autumn occurs in the southern basin, while in winter, it is limited to the northwestern basin. To further discuss the evolution and driving thermodynamic mechanisms, we quantify the processes that control the variability of intraseasonal BL. Different mechanisms for the intraseasonal BL variability for these two active periods are investigated based on the case study and composite analysis. During late summer/autumn, the active BL in the southern basin is generated by advected and local freshwater, and then decays rapidly with the enhanced wind. In winter, anticyclonic eddy activity is associated with the evolution of the BL by affecting the thermocline and halocline variations, while wind stress and wind stress curl have no obvious influence on BL.

Bacterial Community Composition of South China Sea Sediments through Pyrosequencing-Based Analysis of 16S rRNA Genes

PubMed Central

Zhu, Daochen; Tanabe, Shoko-Hosoi; Yang, Chong; Zhang, Weimin; Sun, Jianzhong

2013-01-01

Background Subseafloor sediments accumulate large amounts of organic and inorganic materials that contain a highly diverse microbial ecosystem. The aim of this study was to survey the bacterial community of subseafloor sediments from the South China Sea. Methodology/Principal Findings Pyrosequencing of over 265,000 amplicons of the V3 hypervariable region of the 16S ribosomal RNA gene was performed on 16 sediment samples collected from multiple locations in the northern region of the South China Sea from depths ranging from 35 to 4000 m. A total of 9,726 operational taxonomic units (OTUs; between 695 and 2819 unique OTUs per sample) at 97% sequence similarity level were generated. In total, 40 bacterial phyla including 22 formally described phyla and 18 candidate phyla, with Proteobacteria, Firmicutes, Planctomycetes, Actinobacteria and Chloroflexi being most diverse, were identified. The most abundant phylotype, accounting for 42.6% of all sequences, belonged to Gammaproteobacteria, which possessed absolute predominance in the samples analyzed. Among the 18 candidate phyla, 12 were found for the first time in the South China Sea. Conclusions This study provided a novel insight into the composition of bacterial communities of the South China Sea subseafloor. Furthermore, abundances and community similarity analysis showed that the compositions of the bacterial communities are very similar at phylum level at different depths from 35-4000 m. PMID:24205246

Bacterial community composition of South China Sea sediments through pyrosequencing-based analysis of 16S rRNA genes.

PubMed

Zhu, Daochen; Tanabe, Shoko-Hosoi; Yang, Chong; Zhang, Weimin; Sun, Jianzhong

2013-01-01

Subseafloor sediments accumulate large amounts of organic and inorganic materials that contain a highly diverse microbial ecosystem. The aim of this study was to survey the bacterial community of subseafloor sediments from the South China Sea. Pyrosequencing of over 265,000 amplicons of the V3 hypervariable region of the 16S ribosomal RNA gene was performed on 16 sediment samples collected from multiple locations in the northern region of the South China Sea from depths ranging from 35 to 4000 m. A total of 9,726 operational taxonomic units (OTUs; between 695 and 2819 unique OTUs per sample) at 97% sequence similarity level were generated. In total, 40 bacterial phyla including 22 formally described phyla and 18 candidate phyla, with Proteobacteria, Firmicutes, Planctomycetes, Actinobacteria and Chloroflexi being most diverse, were identified. The most abundant phylotype, accounting for 42.6% of all sequences, belonged to Gammaproteobacteria, which possessed absolute predominance in the samples analyzed. Among the 18 candidate phyla, 12 were found for the first time in the South China Sea. This study provided a novel insight into the composition of bacterial communities of the South China Sea subseafloor. Furthermore, abundances and community similarity analysis showed that the compositions of the bacterial communities are very similar at phylum level at different depths from 35-4000 m.

Four new species of the genus Mannerheimia Mäklin, 1880 (Coleoptera: Staphylinidae: Omaliinae) from south-western China and Taiwan.

PubMed

Shavrin, Alexey V

2018-04-12

Four new species of the genus Mannerheimia Mäklin, 1880 from south-western China and Taiwan are described and illustrated: M. grandilobata Shavrin, sp.n. (China: Yunnan), M. emeishanensis Shavrin, sp.n. (China: Sichuan), M. maculata Shavrin, sp.n. (China: Yunnan) and M. taiwanica Shavrin, sp.n. (Taiwan: Taichung Hsien, Nantou Hsien), the first records of the genus from China and Taiwan. A key to species known from China and Taiwan and distributional maps for each species are provided.

Post-Heading Heat Stress in Rice of South China during 1981-2010

PubMed Central

Shi, Peihua; Tang, Liang; Wang, Lihuan; Sun, Ting; Liu, Leilei; Cao, Weixing; Zhu, Yan

2015-01-01

Frequent extreme heat events are the serious threat to rice production, but the historical trend of heat stress associated with phenology shift and its impact on rice yield over a long period are poorly known. Based on the analysis of observed climate and phenology data from 228 stations in South China during 1981-2010, the spatio-temporal variation of post-heading heat stress was investigated among two single-season rice sub-regions in the northern Middle and Lower Reaches of Yangtze River (S-NMLYtz) and Southwest Plateau (S-SWP), and two double-season early rice sub-regions in the southern Middle and Lower Reaches of Yangtze River (DE-SMLYtz) and Southern China (DE-SC). Post-heading heat stress was more severe in DE-SMLYtz, west S-NMLYtz and east S-SWP than elsewhere, because of rice exposure to the hot season during post-heading stage. The spatial variation of post-heading heat stress was greater in single-season rice region than in double-season early rice region due to the greater spatial variation of heading and maturity dates. Post-heading heat stress increased from 1981 to 2010 in most areas, with significant increases in the east of double-season early rice region and west S-SWP. Phenology shift during 1981-2010 mitigated the increasing trends of heat stress in most areas, but not in west S-SWP. Post-heading heat stress played a dominated role in the reduction of rice yield in South China. Grain yield was more sensitive to post-heading heat stress in double-season early rice region than that in single-season rice region. Rice yield decreased by 1.5%, 6.2%, 9.7% and 4.6% in S-NMLYtz, S-SWP, DE-SMLYtz and DE-SC, respectively, because of post-heading heat stress during 1981-2010, although there were some uncertainties. Given the current level and potential increase of post-heading heat stress in South China, the specific adaptation or mitigation strategies are necessary for different sub-regions to stabilize rice production under heat stress. PMID:26110263

The diplomacy of scientific research in the South China Sea: the case of join to oceanographic marine scientific research expedition between Vietnam and the Philippines

NASA Astrophysics Data System (ADS)

Satyawan, I. A.

2018-03-01

The South China Sea is one of the hot-spot areas in the world. This area is claimed by China, Malaysia, Brunei, Taiwan, Vietnam and the Philippines. It also noted, the South China Sea is rich in biodiversity as well as oil and gas. On the other side, environmental degradation is still happening in the South China Sea due to the reluctance of surrounding states to conduct a preservation program and mitigating action on climate change effects. Joint Oceanographic Marine Scientific Research Expedition between Vietnam and the Philippines is a breakthrough to start collaboration actions as well as to conduct Science Diplomacy.

Tectonic Implications of Paleoproterozoic Deo Khe Granitoids in Northwestern Vietnam

NASA Astrophysics Data System (ADS)

Hoang, T. H. A.; Yu, Y.; Pham, T. H.; Choi, S. H.; Tu, V. L.; Son, L. M.

2015-12-01

An integrated study of petrographic description, zircon U/Pb geochronology, and Hf isotopic analysis was carried out on the medium-grained two-mica Deo Khe Granitoids (DKG) in northwestern Vietnam. U/Pb zircon ages were 1855-1873 Ma, interpreted as the time of magma crystallization. On the basis of Hf isotopic compositions, a single-stage Hf model ages were estimated as 3.3-2.8 Ga. Values of Hf isotopes ɛHf (t) range from -23.6 to -17.5, suggesting that the DKG are products of reworked Archean crustal rocks. A similar sequence of tectonic events including the presence of 2.8-2.9 Ga tonalite-trondhjemite-granodiorite (TTG) gneiss, metamorphic development of TTG gneiss at 1.9-2.0 Ga, and 1.85 Ga magmatic activity were recognized both in Yangtze block and northwestern Vietnam. Therefore we propose that basement rocks in northern Vietnam are similar to those found along southern China.

Sequence of mammalian fossils, including hominoid teeth, from the Bubing Basin caves, South China.

PubMed

Wang, Wei; Potts, Richard; Baoyin, Yuan; Huang, Weiwen; Cheng, Hai; Edwards, R Lawrence; Ditchfield, Peter

2007-04-01

A Plio-Pleistocene to Holocene faunal sequence has been recovered from four carefully excavated caves in the Bubing Basin, adjacent to the larger Bose Basin of South China. The caves vary in elevation; we suggest that the higher caves were formed and filled with sediments prior to the lower caves. The highest deposits, which are from Mohui Cave, contain hominoid teeth and other fossilized remains of mammalian taxa most similar to late Pliocene and early Pleistocene faunas. Wuyun Cave ( approximately 50m lower in elevation than Mohui) contains a late middle Pleistocene fauna, which is supported by U-series age constraints from 350 to 200ka. Lower Pubu Cave ( approximately 23m below Wuyun) is assigned to the late Pleistocene, while the Cunkong Cave (the lowest, approximately 2m lower elevation than Lower Pubu) preserves a Holocene fauna. The four faunal assemblages indicate species-level changes in Ailuropoda, Stegodon, and Sus, the appearance of Elephas, the local disappearance of Stegodon, and the migration of Equus hemionus to South China. These initial results of our work call into question the continued value of the Stegodon/Ailuropoda Fauna, a category long used to characterize the Pleistocene faunas of South China. Excavation of karstic caves of varying elevation within the basins of South China holds promise for defining local sequences of mammalian fossils that can be used to investigate faunal variations related to climate change, biogeographic events, and evolutionary change over the past two million years. Stable isotopic analysis of a small sample of mammalian teeth from Bubing Basin caves is consistent with 100% C(3) vegetation in the Bubing/Bose region, with certain delta(13)C values consistent with a canopied woodland or forest. A preliminary assessment of the hominoid teeth indicates the presence of diverse molar and premolar morphologies including dental remains of Gigantopithecus blacki and a sample with similarities to the teeth reported from

Characterization of Papaya ringspot virus isolates infecting transgenic papaya 'Huanong No.1' in South China.

PubMed

Wu, Zilin; Mo, Cuiping; Zhang, Shuguang; Li, Huaping

2018-05-29

In 2006, the release and cultivation of the genetically modified papaya cultivar 'Huanong No.1' successfully controlled the destructive papaya ringspot disease caused by Papaya ringspot virus (PRSV) in South China. However, some transgenic papaya plants from Guangdong and Hainan are found infected by PRSV. In this study, Field investigation was carried out and susceptible transgenic papaya samples were collected during 2012-2016. Twenty representative isolates were artificially inoculated into Cucurbita pepo and commercialised 'Huanong No.1' papaya, and results indicated that the plants showed obvious disease symptoms. Phylogenetic analysis of CP genes of 120 PRSV-infected isolates showed that PRSV can be divided into three groups. Isolates from Guangdong and Hainan belong to Group III, which is further divided into two subgroups. The isolates collected in this study have greatly diverged from the previously reported dominant strains Ys, Vb and Sm in South China, indicating that they belong to a new lineage. Further analysis showed a highly genetic differentiation between isolates, and 27.1% of the isolates were identified as recombinants on the basis of CP nucleotide sequences. These results indicate that the genetic variation of PRSV and the formation of the new virus lineage may explain the loss of transgenic papaya resistance in South China.

Bioprospecting of Novel and Bioactive Compounds from Marine Actinomycetes Isolated from South China Sea Sediments.

PubMed

Yang, Na; Song, Fuhang

2018-02-01

Marine actinomycetes are less investigated compared to terrestrial strains as potential sources of natural products. To date, few investigations have been performed on culturable actinomycetes associated with South China Sea sediments. In the present study, twenty-eight actinomycetes were recovered from South China Sea sediments after dereplication by traditional culture-dependent method. The 16S rRNA gene sequences analyses revealed that these strains related to five families and seven genera. Twelve representative strains possessed at least one of the biosynthetic genes coding for polyketide synthase I, II, and nonribosomal peptide synthetase. Four strains had anti-Mycobacterium phlei activities and five strains had activities against methicillin-resistant Staphylococcus aureus. 10 L-scale fermentation of strains Salinispora sp. NHF45, Nocardiopsis sp. NHF48, and Streptomyces sp. NHF86 were carried out for novel and bioactive compounds discovery. Finally, we obtained a novel α-pyrone compound from marine Nocardiopsis sp. NHF48, an analogue of paulomenol from marine Streptomyces sp. NHF86 and a new source of rifamycin B, produced by Salinispora sp. NHF45. The present study concluded that marine actinomycetes, which we isolated from South China Sea sediments, will be a suitable source for the development of novel and bioactive compounds.

Modal recovery of sea-level variability in the South China Sea using merged altimeter data

NASA Astrophysics Data System (ADS)

Jiang, Haoyu; Chen, Ge

2015-09-01

Using 20 years (1993-2012) of merged data recorded by contemporary multi-altimeter missions, a variety of sea-level variability modes are recovered in the South China Sea employing three-dimensional harmonic extraction. In terms of the long-term variation, the South China Sea is estimated to have a rising sea-level linear trend of 5.39 mm/a over these 20 years. Among the modes extracted, the seven most statistically significant periodic or quasi-periodic modes are identified as principal modes. The geographical distributions of the magnitudes and phases of the modes are displayed. In terms of intraannual and annual regimes, two principal modes with strict semiannual and annual periods are found, with the annual variability having the largest amplitudes among the seven modes. For interannual and decadal regimes, five principal modes at approximately 18, 21, 23, 28, and 112 months are found with the most mode-active region being to the east of Vietnam. For the phase distributions, a series of amphidromes are observed as twins, termed "amphidrome twins", comprising rotating dipole systems. The stability of periodic modes is investigated employing joint spatiotemporal analysis of latitude/longitude sections. Results show that all periodic modes are robust, revealing the richness and complexity of sea-level modes in the South China Sea.

Interannual variation of the South China Sea circulation during winter: intensified in the southern basin

NASA Astrophysics Data System (ADS)

Zu, Tingting; Xue, Huijie; Wang, Dongxiao; Geng, Bingxu; Zeng, Lili; Liu, Qinyan; Chen, Ju; He, Yunkai

2018-05-01

Surface geostrophic current derived from altimetry remote sensing data, and current profiles observed from in-situ Acoustic Doppler Current Profilers (ADCP) mooring in the northern South China Sea (NSCS) and southern South China Sea (SSCS) are utilized to study the kinetic and energetic interannual variability of the circulation in the South China Sea (SCS) during winter. Results reveal a more significant interannual variation of the circulation and water mass properties in the SSCS than that in the NSCS. Composite ananlysis shows a significantly reduced western boundary current (WBC) and a closed cyclonic eddy in the SSCS at the mature phase of El Niño event, but a strong WBC and an unclosed cyclonic circulation in winter at normal or La Niña years. The SST is warmer while the subsurface water is colder and fresher in the mature phase of El Niño event than that in the normal or La Niña years in the SSCS. Numerical experiments and energy analysis suggest that both local and remote wind stress change are important for the interannual variation in the SSCS, remote wind forcing and Kuroshio intrusion affect the circulation and water mass properties in the SSCS through WBC advection.

[Assessment on the yield loss risk of longan caused by cold damage in South China].

PubMed

Zhao, Jun-fang; Yu, Hui-kang

2016-02-01

Using daily climate variables gathered from 64 meteorological stations in South China from 1961 to 2012, recognized hazard indicators about disaster grades of cold damage for longan, and methods on agricultural meteorological disasters risk and simulation technology, the yield loss risks of longan caused by cold damage in South China during different developmental periods were assessed. The results showed that during the period of physiologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage. The hazards caused by cold damage under different grades varied. In particular, under mild cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. Under moderate cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, and Fujian was serious. Under severe cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, Fujian was serious. During the period of morphologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage, while the disasters of longan under mild, moderate and severe cold damages within this period were similar. Specifically, light disasters of longan were all found in Hainan, followed by Guangdong, Guangxi and Fujian. During the period of dormancy, the disaster of longan affected by mild cold damage in South China was the most common, followed by severe cold damage and moderate cold damage. Under mild and severe cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. However, under moderate cold damage, light disaster of longan was found in Hainan and Guangxi, followed by Guangdong, and Fujian was serious. At the same level

Climate extremes in Malaysia and the equatorial South China Sea

NASA Astrophysics Data System (ADS)

Salahuddin, Ahmed; Curtis, Scott

2011-08-01

The southern extent of the South China Sea (SCS) is an important natural resource epicenter for Malaysia which experiences climate extremes. This paper documents the variability of extremes in the equatorial SCS through selected ground-based observations of precipitation in Malaysia and ship-based observations of wind data in the Maritime Continent region, to elucidate the interrelationship between precipitation variability over Malaysia and wind variability over the ocean. The data have been carefully inspected and analyzed, and related to the real-time multivariate Madden-Julian Oscillation (MJO) time series. The analysis suggests that the northeast or boreal winter monsoon dominates extreme rainfall in eastern Malaysian cities. Further, the west coast of Peninsular Malaysia and Borneo Malaysia are affected by the MJO differently than the east coast of Peninsular Malaysia. From the wind analysis we found that average zonal wind is westerly from May to September and easterly from November to April. When the active (convective) phase of the MJO is centered over the Maritime Continent, the strong westerly wind bursts are more frequent in the South China Sea. While more investigation is needed, these results suggest that the status of the Madden-Julian Oscillation can be used to help forecast climate extremes in areas of Malaysia.

How Universities Work: Understanding Higher Education Organization in Northwest China

ERIC Educational Resources Information Center

Berger, Joseph B.; Hudson, Katherine E.; Ramirez, Gerardo Blanco

2013-01-01

This study explores models of educational management used in postsecondary institutions in the five northwestern provinces of the People's Republic of China (Gansu, Ningxia, Qinghai, Shaanxi, and Xinjiang). As higher education in the People's Republic of China expands and undergoes significant changes, a nuanced understanding of the organizational…

Biogeochemistry of a treeline watershed, northwestern Alaska

USGS Publications Warehouse

Stottlemyer, R.

2001-01-01

Since 1950, mean annual temperatures in northwestern Alaska have increased. Change in forest floor and soil temperature or moisture could alter N mineralization rates, production of dissolved organic carbon (DOC) and organic nitrogen (DON), and their export to the aquatic ecosystem. In 1990, we began study of nutrient cycles in the 800-ha Asik watershed, located at treeline in the Noatak National Preserve, northwestern Alaska. This paper summarizes relationships between topographic aspect, soil temperature and moisture, inorganic and organic N pools, C pools, CO2 efflux, growing season net N mineralization rates, and stream water chemistry. Forest floor (O2) C/N ratios, C pools, temperature, and moisture were greater on south aspects. More rapid melt of the soil active layer (zone of annual freeze-thaw) and permafrost accounted for the higher moisture. The O2 C and N content were correlated with moisture, inorganic N pools, CO2 efflux, and inversely with temperature. Inorganic N pools were correlated with temperature and CO2 efflux. Net N mineralization rates were positive in early summer, and correlated with O2 moisture, temperature, and C and N pools. Net nitrification rates were inversely correlated with moisture, total C and N. The CO2 efflux increased with temperature and moisture, and was greater on south aspects. Stream ion concentrations declined and DOC increased with discharge. Stream inorganic nitrogen (DIN) output exceeded input by 70%. Alpine stream water nitrate (NO-3) and DOC concentrations indicated substantial contributions to the watershed DIN and DOC budgets.

Biogeochemistry of a treeline watershed, northwestern Alaska.

PubMed

Stottlemyer, R

2001-01-01

Since 1950, mean annual temperatures in northwestern Alaska have increased. Change in forest floor and soil temperature or moisture could alter N mineralization rates, production of dissolved organic carbon (DOC) and organic nitrogen (DON), and their export to the aquatic ecosystem. In 1990, we began study of nutrient cycles in the 800-ha Asik watershed, located at treeline in the Noatak National Preserve, northwestern Alaska. This paper summarizes relationships between topographic aspect, soil temperature and moisture, inorganic and organic N pools, C pools, CO2 efflux, growing season net N mineralization rates, and stream water chemistry. Forest floor (O2) C/N ratios, C pools, temperature, and moisture were greater on south aspects. More rapid melt of the soil active layer (zone of annual freeze-thaw) and permafrost accounted for the higher moisture. The O2 C and N content were correlated with moisture, inorganic N pools, CO2 efflux, and inversely with temperature. Inorganic N pools were correlated with temperature and CO2 efflux. Net N mineralization rates were positive in early summer, and correlated with O2 moisture, temperature, and C and N pools. Net nitrification rates were inversely correlated with moisture, total C and N. The CO2 efflux increased with temperature and moisture, and was greater on south aspects. Stream ion concentrations declined and DOC increased with discharge. Stream inorganic nitrogen (DIN) output exceeded input by 70%. Alpine stream water nitrate (NO3-) and DOC concentrations indicated substantial contributions to the watershed DIN and DOC budgets.

Phylogeography and pigment type diversity of Synechococcus cyanobacteria in surface waters of the northwestern pacific ocean.

PubMed

Xia, Xiaomin; Partensky, Frédéric; Garczarek, Laurence; Suzuki, Koji; Guo, Cui; Yan Cheung, Shun; Liu, Hongbin

2017-01-01

The widespread unicellular cyanobacteria Synechococcus are major contributors to global marine primary production. Here, we report their abundance, phylogenetic diversity (as assessed using the RNA polymerase gamma subunit gene rpoC1) and pigment diversity (as indirectly assessed using the laterally transferred cpeBA genes, encoding phycoerythrin-I) in surface waters of the northwestern Pacific Ocean, sampled over nine distinct cruises (2008-2015). Abundance of Synechococcus was low in the subarctic ocean and South China Sea, intermediate in the western subtropical Pacific Ocean, and the highest in the Japan and East China seas. Clades I and II were by far the most abundant Synechococcus lineages, the former dominating in temperate cold waters and the latter in (sub)tropical waters. Clades III and VI were also fairly abundant in warm waters, but with a narrower distribution than clade II. One type of chromatic acclimater (3dA) largely dominated the Synechococcus communities in the subarctic ocean, while another (3dB) and/or cells with a fixed high phycourobilin to phycoerythrobilin ratio (pigment type 3c) predominated at mid and low latitudes. Altogether, our results suggest that the variety of pigment content found in most Synechococcus clades considerably extends the niches that they can colonize and therefore the whole genus habitat. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Isolation, molecular characterization, and phylogenetic analysis of encephalomyocarditis virus from South China tigers in China.

PubMed

Liu, Huimin; Yan, Qi; Zhao, Bo; Luo, Jing; Wang, Chengmin; Du, Yingchun; Yan, Jing; He, Hongxuan

2013-10-01

Although encephalomyocarditis virus (EMCV) can infect many host species and cause myocarditis and sudden death in many species, little is known about EMCV infection in tigers. A virus was isolated from organs of dead South China tigers with sudden death in southern China. The production of cytopathic effect on BHK cells, and the results of PCR, electron microscopy (EM), and whole genome sequencing indicated that the pathogen was EMCV, the strain was named FJ13. Other pathogenic agents were excluded as possible pathogenic agents. Phylogenetic analyses of the whole genome, ORF (open reading frame) and CCR (capsid coding region) using the neighbour-joining method revealed that EMCV isolates cluster into two groups (group 1 and 2) with two sub-clusters within group 1 (group 1a and 1b), and FJ13 belongs to group 1a. Animal experiment showed that the isolated strain FJ13 could cause clinical symptoms and pathological changes. The results of this study indicated that FJ13 caused myocarditis of tigers and provided new epidemiologic data on EMCV in China. Copyright © 2013 Elsevier B.V. All rights reserved.

Petrogenesis and tectonic implications of an Early Jurassic magmatic arc from South to East China Seas

NASA Astrophysics Data System (ADS)

Zhang, L.; Xu, C.

2017-12-01

Granite and diorite samples by drilling in northeastern South China Sea (SCS) and southwestern East China Sea (ECS) contribute key information to understanding tectonic regime of South China Block in Jurassic time. SIMS and LA-ICPMS U-Pb zircon analyses yield ages ranging from 195±2 Ma to 198±1 Ma for samples from well LF3511 in SCS, and an age of 187±1 Ma for the sample from well ESC635 in ECS. They are low temperature I-type granitoids with strongly enriched fluid-mobile elements and depleted Nb-Ta features, indicating subduction arc-related magmatism in their origin. Sr-Nd isotopic compositions for samples from SCS ((87Sr/86Sr)i=0.705494-0.706623, ɛNdt=-0.9 to +2.2) and sample from ECS ((87Sr/86Sr)i=0.705200, ɛNdt=1.1) suggest an affinity with evolved mantle-derived melts. The granitoids found from NE SCS, SE Taiwan to the SW ECS could spatially define an Early Jurassic NE-SW-trending Dongsha-Talun-Yandang low-temperature magmatic arc zone along the East Asian continental margin, paired with Jurassic accretionary complexes exposed in SW Japan, E Taiwan to the W Philippines. Its geodynamic context is associated with oblique subduction of the paleo-Pacific slab beneath Eurasia, as a mechanism responsible for early Jurassic lithospheric extension with magmatism in the South China Block.

Occurrence and distribution of conventional and new classes of per- and polyfluoroalkyl substances (PFASs) in the South China Sea.

PubMed

Kwok, Karen Y; Wang, Xin-Hong; Ya, Miaolei; Li, Yongyu; Zhang, Xiao-Hua; Yamashita, Nobuyoshi; Lam, James C W; Lam, Paul K S

2015-03-21

Concentrations of 23 per- and polyfluoroalkyl substances (PFASs), including new classes of PFASs, in seawater samples were investigated for their occurrence and the interaction of the ocean currents with the distribution of PFASs in the South China Sea. This study revealed that socio-economic development was associated with the PFAS contamination in coastal regions of South China. Significant correlations between concentration of total PFASs with gross domestic product (GDP) per capita and population density were found in the areas, suggesting that the influence of intense human activities in these areas may have resulted in higher PFAS contamination to the adjacent environment. Di-substituted polyfluoroalkyl phosphate (diPAP), one of the potential replacements for PFASs, was only detected in the heavily developed region, namely Pearl River Delta (PRD). Total PFAS concentrations, ranging from 195 to 4925 pg/L, were detected at 51 sampling stations of the South China Sea. The results also confirmed that PFAS contamination in the South China Sea is strongly affected by the ocean currents. In comparison to perfluoroactane sulfonate (PFOS) concentrations measured nine years ago at the same locations, the concentrations in this study were found to be two times higher. This indicated that the use and production of perfluoroalkyl sulfonates (PFSAs) has been continuing in the region. Copyright © 2014 Elsevier B.V. All rights reserved.

Return to Clark Air Force Base: Establishing Permanent Military Bases in the Philippines as part of the United States Grand Strategy in the South China Sea

DTIC Science & Technology

2016-02-16

Unknotting tangled Lines in the South China Sea Dispute” in Territorial Disputes in the South China Sea ed. Billo, Andrew and Jung 1-12 Hayton...in Territorial Disputes in the South China Sea ed. Billo, Andrew and Jung 99-127 Johnston, Alastair, “How New and Assertive Is China’s New...2015) Sutter, Robert, “China’s Rise: Implications for U.S. Leadership in Asia,” East-West Center, Washington, Policy Studies 21. (2006) Thayer, Carl

Sediment compaction in deepwater basin of the South China Sea: estimation from ODP 184 and IODP 349 drilling well data.

NASA Astrophysics Data System (ADS)

Tuoyu, W.; Xie, Y.

2017-12-01

Abnormal compaction in deepwater basins not only cause serious soft sediment deformation, but also significantly affect the safety of the drilling campaign. Therefore, study the compaction condition in the sediments would be an important task in the deepwater basin and associate with the environment variation. We analyze the drilling data from the ODP Leg 184 Site 1144, 1146, 1148 and the IODP Leg 349 Site U1431, U1432, U1433, U1435 to study the sediment compaction and controls in the northern South China Sea. We have found the sedimentation rate, sediment content, distribution area and buried depth control the sediment compaction in deepwater basin of the South China Sea. Among all the factors, the sediment content is the most important factor. The fitted normal compacted coefficients and the mudline porosity for interval 50 m shows disciplinary variation versus depth. The pore pressure predicted from different fitted results shows different overpressure situation. The normal compaction trend from Site 1144 reflects the porosity variation trend in stable deposition basins in the northern South China Sea. The predicted pore pressure shows overpressure at Site 1144, which is attributed to compaction disequilibrium. Nevertheless, the mixed lithology column may influence the predicted overpressure at Site 1148, which is responsible for the confusing result. Above all. we find that sediment compaction should be act as a proxy for pore pressure in the deepwater basin of the South China Sea. The study will help us to nature of sedimentation in the deepwater basin set up and can be used as analog for older sediments deposited in the similar kind of depositional environment in deepwater basin of the South China Sea.

Detection of aerosol pollution sources during sandstorms in Northwestern China using remote sensed and model simulated data

NASA Astrophysics Data System (ADS)

Filonchyk, Mikalai; Yan, Haowen; Yang, Shuwen; Lu, Xiaomin

2018-02-01

The present paper has used a comprehensive approach to study atmosphere pollution sources including the study of vertical distribution characteristics, the epicenters of occurrence and transport of atmospheric aerosol in North-West China under intensive dust storm registered in all cities of the region in April 2014. To achieve this goal, the remote sensing data using Moderate Resolution Imaging Spectroradiometer satellite (MODIS) as well as model-simulated data, were used, which facilitate tracking the sources, routes, and spatial extent of dust storms. The results of the study have shown strong territory pollution with aerosol during sandstorm. According to ground-based air quality monitoring stations data, concentrations of PM10 and PM2.5 exceeded 400 μg/m3 and 150 μg/m3, respectively, the ratio PM2.5/PM10 being within the range of 0.123-0.661. According to MODIS/Terra Collection 6 Level-2 aerosol products data and the Deep Blue algorithm data, the aerosol optical depth (AOD) at 550 nm in the pollution epicenter was within 0.75-1. The vertical distribution of aerosols indicates that the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) 532 nm total attenuates backscatter coefficient ranges from 0.01 to 0.0001 km-1 × sr-1 with the distribution of the main types of aerosols in the troposphere of the region within 0-12.5 km, where the most severe aerosol contamination is observed in the lower troposphere (at 3-6 km). According to satellite sounding and model-simulated data, the sources of pollution are the deserted regions of Northern and Northwestern China.

Evolutionary mechanisms shaping the genetic population structure of coastal fish: insight from populations of Coilia nasus in Northwestern Pacific.

PubMed

Gao, Tianxiang; Wan, Zhenzhen; Song, Na; Zhang, Xiumei; Han, Zhiqiang

2014-12-01

A number of evolutionary mechanisms have been suggested for generating significant genetic structuring among marine fish populations in Northwestern Pacific. We used mtDNA control region to assess the factors in shaping the genetic structure of Japanese grenadier anchovy, Coilia nasus, an anadromous and estuarine coastal species, in Northwestern Pacific. Sixty seven individuals from four locations in Northwestern Pacific were sequenced for mitochondrial control region, detecting 61 haplotypes. The length of amplified control region varied from 677 to 754 bp. This length variability was due to the presence of varying numbers of a 38-bp tandemly repeated sequence. Two distinct lineages were detected, which might have diverged during Pleistocene low sea levels. There were strong differences in the geographical distribution of the two lineages. Analyses of molecular variance and the population statistic ΦST revealed significant genetic structure between China and Ariake Bay populations. Based on the frequency distribution of tandem repeat units, significant genetic differentiation was also detected between China and Ariake Bay populations. Isolation by distance seems to be the main factor driving present genetic structuring of C. nasus populations, indicating coastal dispersal pattern in this coastal species. Such an evolutionary process agrees well with some of the biological features characterizing this species.

Scramble in the South China Sea: Regional Conflict and U.S. Strategy

DTIC Science & Technology

2013-02-14

Basin Phu Kanh Basin Cuu Long Basin Nam Con Son Basin South China Sea Platform Baram Delta Basin Palawan Shelf Basin Greater Sarawak Basin...Basin 183 10,599 Greater Sarawak Basin 618 34,083 Phu Kanh Basin 116 10,679 Baram Delta Basin 4,056 12,546 Cuu Long Basin 1,599 487 Palawan Shelf

Molecular characterization and phylogenetic analysis of infectious bursal disease viruses isolated from chicken in South China in 2011.

PubMed

Liu, Di; Zhang, Xiang-Bin; Yan, Zhuan-Qiang; Chen, Feng; Ji, Jun; Qin, Jian-Ping; Li, Hai-Yan; Lu, Jun-Peng; Xue, Yu; Liu, Jia-Jia; Xie, Qing-Mei; Ma, Jing-Yun; Xue, Chun-Yi; Bee, Ying-Zuo

2013-06-01

Infectious bursal disease virus (IBDV) is a double-stranded RNA virus that causes immunosuppressive disease in young chickens. Thousands of cases of IBDV infection are reported each year in South China, and these infections can result in considerable economic losses to the poultry industry. To monitor variations of the virus during the outbreaks, 30 IBDVs were identified from vaccinated chicken flocks from nine provinces in South China in 2011. VP2 fragments from different virus strains were sequenced and analyzed by comparison with the published sequences of IBDV strains from China and around the world. Phylogenetic analysis of hypervariable regions of the VP2 (vVP2) gene showed that 29 of the isolates were very virulent (vv) IBDVs, and were closely related to vvIBDV strains from Europe and Asia. Alignment analysis of the deduced amino acid (aa) sequences of vVP2 showed the 29 vv isolates had high uniformity, indicated low variability and slow evolution of the virus. The non-vvIBDV isolate JX2-11 was associated with higher than expected mortality, and had high deduced aa sequence similarity (99.2 %) with the attenuated vaccine strain B87 (BJ). The present study has demonstrated the continued circulation of IBDV strains in South China, and emphasizes the importance of reinforcing IBDV surveillance.

Did opening of the South China Sea impact development of the Asian Monsoon? Results from Oligocene microfossils, IODP Site U1435, northern South China Sea

NASA Astrophysics Data System (ADS)

Kulhanek, Denise K.; Su, Xin; Li, Qianyu; Gregory, Mitch; Warny, Sophie; Clift, Peter D.

2016-04-01

Development of the Asian Monsoon is linked to uplift of the Himalayas and Tibetan Plateau in the Cenozoic, with good evidence for a strong monsoon system by the late Oligocene to early Miocene (e.g., Guo et al., 2002; Clift et al., 2008). However, Licht et al. (2014) suggested the presence of an Asian Monsoon in the late Eocene. Recent scientific ocean drilling in the Indian Ocean and surrounding marginal seas gives us the opportunity to test this hypothesis with newly recovered Paleogene sediment cores. International Ocean Discovery Program Expedition 349 to the South China Sea recovered a 30 m section of primarily lower Oligocene nannofossil-rich claystone at Site U1435, located near the northern continent/ocean boundary. A thick sandstone unit devoid of typical marine microfossils underlies the marine claystone. The sandstone is interpreted as a deltaic or restricted marine deposit and is dated to the Eocene based on the presence of organic-walled palynomorphs, suggesting that a hiatus of several million years likely separates the sandstone below from the Oligocene marine claystone. This hiatus is interpreted as the breakup unconformity, with paleodepths in the South China Sea increasing during the Oligocene. Thus, this claystone should record if opening of the South China Sea during the early Oligocene influenced development of the Asian Monsoon. Combined calcareous nannofossil and planktonic foraminifer biostratigraphy indicates that the 30 m section is primarily early Oligocene in age (~33.5-30 Ma) and was deposited on the middle slope, with paleodepths >500 m. Stable oxygen isotopes from planktonic foraminifers become heavier up-hole, suggestive of cooling/deepening in the region, whereas carbon isotopes record variable conditions with no distinct maxima or minima. Calcareous nannoplankton primarily live in the upper 50 m of the ocean and are sensitive to sea-surface temperature and nutrient conditions, thus making them useful recorders of paleoceanographic

Preliminary evidence for a 1000-year-old tsunami in the South China Sea

PubMed Central

Sun, Liguang; Zhou, Xin; Huang, Wen; Liu, Xiaodong; Yan, Hong; Xie, Zhouqing; Wu, Zijun; Zhao, Sanping; Da Shao; Yang, Wenqing

2013-01-01

The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area. PMID:23575432

Preliminary evidence for a 1000-year-old tsunami in the South China Sea.

PubMed

Sun, Liguang; Zhou, Xin; Huang, Wen; Liu, Xiaodong; Yan, Hong; Xie, Zhouqing; Wu, Zijun; Zhao, Sanping; Da Shao; Yang, Wenqing

2013-01-01

The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area.

Crustal and uppermost mantle structures of the South China from joint analysis of receiver functions and Rayleigh wave dispersions

NASA Astrophysics Data System (ADS)

Guo, Zhi; Gao, Xing; Li, Tong; Wang, Wei

2018-05-01

We use P-wave receiver function H-k stacking and joint inversion of receiver functions and Rayleigh wave dispersions to investigate crustal and uppermost mantle structure beneath the South China. The obtained results reveal prominent crustal structure variations in the study area, Moho depth increases from ∼30 km in the Cathaysia Block to more than ∼60 km in the eastern Tibetan Plateau. A Moho undulation and Vp/Vs ratio variations can be observed from the Cathaysia Block to Yangtze Craton. These observations consistent with the crustal structures predict by the flat slab subduction model. We interpret these lateral crustal structure variations reflect the tectonic evolution of the Yangtze Craton and Cathaysia Block prior the Mesozoic and the post-orogenic magmatism due to the breaking up of the subducted flat slab and subsequent slab rollback in the South China. The observed variations of the crustal structures not only reveal the lateral crustal inhomogeneity, but also provide constraints on the geodynamic evolution of the South China.

Recent advances in research on the aeolian geomorphology of China's Kumtagh Sand Sea

NASA Astrophysics Data System (ADS)

Dong, Z.; Lv, P.

2014-02-01

The Kumtagh Sand Sea in the hyper-arid region of northwestern China remained largely unexplored until the last decade. It deserves study due to its significance in understanding the evolution of the arid environments in northwestern China, and even central Asia. Aeolian geomorphology in the sand sea has received unprecedented study in the last decade. Encouraging advances have been made in types of aeolian landforms, geological outlines, wind systems, the formation of aeolian landforms, several unique aeolian landforms, aeolian geomorphic regionalization, aeolian geomorphological heritages and tourism development, and aeolian sand hazards and their control. These advances expand our knowledge of aeolian geomorphology.

Seismic imaging of gas hydrates in the northernmost South China sea

NASA Astrophysics Data System (ADS)

Wang, Tan K.; Yang, Ben Jhong; Deng, Jia-Ming; Lee, Chao-Shing; Liu, Char-Shine

2010-03-01

Horizon velocity analysis and pre-stack depth migration of seismic profiles collected by R/V Maurice Ewing in 1995 across the accretionary prism off SW Taiwan and along the continental slope of the northernmost South China Sea were implemented for identifying gas hydrates. Similarly, a survey of 32 ocean-bottom seismometers (OBS), with a spacing of about 500 m, was conducted for exploring gas hydrates on the accretionary prism off SW Taiwan in April 2006. Travel times of head wave, refraction, reflection and converted shear wave identified from the hydrophone, vertical and horizontal components of these OBS data were applied for imaging P-wave velocity and Poisson’s ratio of hydrate-bearing sediments. In the accretionary prism off SW Taiwan, we found hydrate-bearing sediment, with a thickness of about 100-200 m, a relatively high P-wave velocity of 1.87-2.04 km/s and a relatively low Poisson’s ratio of 0.445-0.455, below anticlinal ridges near imbricate emergent thrusts in the drainage system of the Penghu and Kaoping Canyons. Free-gas layer, with a thickness of about 30-120 m, a relatively low P-wave velocity of 1.4-1.8 km/s and a relatively high Poisson’s ratio (0.47-0.48), was also observed below most of the bottom-simulating reflectors (BSR). Subsequently, based on rock physics of the three-phase effective medium, we evaluated the hydrate saturation of about 12-30% and the free-gas saturation of about 1-4%. The highest saturation (30% and 4%) of gas hydrates is found below anticlines due to N-S trending thrust-bounded folds and NE-SW thrusting and strike-slip ramps in the lower slope of the accretionary prism. We suggest that fluid may have migrated through the relay-fault array due to decollement folding and gas hydrates have been trapped in anticlines formed by the basement rises along the thrust faults. In contrast, in the rifted continental margin of the northernmost South China Sea, P-wave velocities of 1.9-2.2 km/s and 1.3-1.6 km/s, and thicknesses

Alkaline digestion and solid phase extraction method for perfluorinated compounds in mussels and oysters from South China and Japan.

PubMed

So, M K; Taniyasu, S; Lam, P K S; Zheng, G J; Giesy, J P; Yamashita, N

2006-02-01

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), have been identified in the coastal waters of China and Japan. An alkaline digestion method, coupled with solid-phase extraction (SPE), and high-performance liquid chromatography interfaced with high-resolution electrospray tandem mass spectrometry was developed to determine PFCs in mussel and oyster samples from coastal waters of South China and Japan. These techniques produced adequate recoveries and reporting limits with small quantities of PFCs. Concentrations of individual PFCs in mussels and oysters from South China and Japan ranged from 113.6 to 586.0 pg/g, wet weight (ww) for PFOS, 63.1 to 511.6 pg/g, ww for perfluorohexane sulfonate, 9.3 to 30.1 pg/g, ww for perfluorobutane sulfonate and 37.8 to 2957.0 pg/g, ww for perfluorooctane sulfonamide. The quantification of perfluorinated carboxylates was compromised by interferences from carboxylates in the procedural blanks. Perfluoroundecanoate and perfluorononanoate had relatively great blank interferences, which resulted in relatively poor limits of quantification for these compounds. Some PFCs were only identified in a limited number of samples: perfluorododecanoate in samples from Tokyo Bay, Japan (195.9 pg/g, ww); and perfluorodecanoate in Fuzhou, China (131.7 pg/g, ww) and Tokyo Bay (118.6 pg/g, ww). The greatest concentrations of perfluorooctanoate, perfluoroheptanoate, and perfluorohexanoate were observed in samples from Tokyo Bay and Bei Hai, South China.

Nonlinear Meridional Moisture Advection and the ENSO-Southern China Rainfall Teleconnection

NASA Astrophysics Data System (ADS)

Wang, Qiang; Cai, Wenju; Zeng, Lili; Wang, Dongxiao

2018-05-01

In the boreal cooler months of 2015, southern China (SC) experienced the largest rainfall since 1950, exceeding 4 times the standard deviation of SC rainfall. Although an El Niño typically induces a positive SC rainfall anomaly during these months, the unprecedented rainfall increase cannot be explained by the strong El Niño of 2015/2016, and the dynamics is unclear. Here we show that a nonlinear meridional moisture advection contributes substantially to the unprecedented rainfall increase. During cooler months of 2015, the meridional flow anomaly over the South China Sea region, which acts on an El Niño-induced anomalous meridional moisture gradient, is particularly large and is supported by an anomalous zonal sea surface temperature gradient over the northwestern Pacific, which recorded its largest value in 2015 since 1950. Our study highlights, for the first time, the importance of the nonlinear process associated with the combined impact of a regional sea surface temperature gradient and large-scale El Niño anomalies in forcing El Niño rainfall teleconnection.

Changes in monsoon-driven upwelling in the South China Sea over glacial Terminations I and II: a multi-proxy record

NASA Astrophysics Data System (ADS)

Sadatzki, Henrik; Sarnthein, Michael; Andersen, Nils

2016-06-01

Upwelling intensity in the South China Sea has changed over glacial-interglacial cycles in response to orbital-scale changes in the East Asian Monsoon. Here, we evaluate new multi-proxy records of two sediment cores from the north-eastern South China Sea to uncover millennial-scale changes in winter monsoon-driven upwelling over glacial Terminations I and II. On the basis of U/Th-based speleothem chronology, we compare these changes with sediment records of summer monsoon-driven upwelling east of South Vietnam. Ocean upwelling is traced by reduced (UK'37-based) temperature and increased nutrient and productivity estimates of sea surface waters (δ13C on planktic foraminifera, accumulation rates of alkenones, chlorins, and total organic carbon). Accordingly, strong winter upwelling occurred north-west of Luzon (Philippines) during late Marine Isotope Stage 6.2, Heinrich (HS) and Greenland stadials (GS) HS-11, GS-26, GS-25, HS-1, and the Younger Dryas. During these stadials, summer upwelling decreased off South Vietnam and sea surface salinity reached a maximum suggesting a drop in monsoon rains, concurrent with speleothem records of aridity in China. In harmony with a stadial-to-interstadial see-saw pattern, winter upwelling off Luzon in turn was weak during interstadials, in particular those of glacial Terminations I and II, when summer upwelling culminated east of South Vietnam. Most likely, this upwelling terminated widespread deep-water stratification, coeval with the deglacial rise in atmospheric CO2. Yet, a synchronous maximum in precipitation fostered estuarine overturning circulation in the South China Sea, in particular as long as the Borneo Strait was closed when sea level dropped below -40 m.

Bluetongue disease and seroprevalence in South American camelids from the northwestern region of the United States.

PubMed

Allen, Andrew J; Stanton, James B; Evermann, James F; Fry, Lindsay M; Ackerman, Melissa G; Barrington, George M

2015-03-01

In late summer/early fall of 2013, 2 South American camelids from central Washington were diagnosed with fatal bluetongue viral disease, an event which is rarely reported. A 9-year-old intact male llama (Lama glama), with a 1-day history of anorexia, recumbency, and dyspnea before death. Abundant foam discharged from the mouth and nostrils, and the lungs were severely edematous on postmortem examination. Histologically, there was abundant intra-alveolar edema with fibrin. Hemorrhage and edema disrupted several other organs. Bluetongue viral RNA was detected by reverse transcription polymerase chain reaction (RT-PCR), and serotype 11 was identified by sequencing a segment of the VP2 outer capsid gene. Approximately 1 month later, at a site 150 miles north of the index case, a 2-year-old female alpaca with similar, acutely progressive clinical signs was reported. A postmortem examination was performed, and histologic lesions from the alpaca were similar to those of the llama, and again serotype 11 was detected by PCR. The occurrence of bluetongue viral infection and disease is described in the context of seasonal Bluetongue virus activity within the northwestern United States and southwestern Canada. © 2015 The Author(s).

Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, China.

PubMed

He, Ping; Wang, Bao-zhong

2003-03-01

As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of China is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the ecotourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of China national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

Anthropogenic Air Pollution Observed Near Dust Source Regions in Northwestern China During Springtime 2008

NASA Technical Reports Server (NTRS)

Li, Can; Tsay, Si-Chee; Fu, Joshua S.; Dickerson, Russell R.; Ji, Qiang; Bell, Shaun W.; Gao, Yang; Zhang, Wu; Huang, Jianping; Li, Zhanqing;

The collision process deciphered form the systematic metamorphic pattern along the Qinling-Dabie-Hongseong collision belt between the North and South China(Korea-China) blocks

NASA Astrophysics Data System (ADS)

Oh, C. W.

2016-12-01

As a last step of formation of the Pangea supercontinent, the North China craton collided with the South China craton during Permo-Triassic time forming the Qinling-Dabie-Sulu collision belt. After the Qinling-Dabie-Sulu collision belt was found, the Imjingang belt in Korean Peninsula was suggested as an extension of the belt but evidences of collision belt such as eclogite and ophiolite, were not found from the belt. Whereas Triassic eclogite (ca. >230 Ma) was found in the Hongseong area and Triassic post collision igneous rocks (with ca. 230 Ma intrusion ages) occurred throughout the Gyeonggi massif locating to the north of the line connecting the Hongseong, Yangpyeong and Odesan areas. These new findings suggest the Permo-Triassic Qinling-Dabie-Sulu collision belt between the North and South China cratons extends into the Hongseong-Yangpyeong-Odesan collision belt in Korean Peninsula. Therefore I would like to suggest the North and South Korea-China cratons instead of the North and South China cratons. The collision had started from Korea at ca. 250 Ma and propagated towards China until late Triassic. The metamorphic conditions change systematically along the collision belt; ultrahigh-temperature metamorphism in the Odesan area (at 245 Ma; 9.0-10.6 kbar, 915-1160°C), high-P/T metamorphism in the Hongseong area (at > 230 Ma; 17.0-21.9 kbar, 835-860°C), ultrahigh-pressure metamorphism in the Dabie and Sulu belts (at 230-220 Ma; 30-40 kbar, 680-880°C), ultrahigh-pressure metamorphism in the Hongan belt (at 225-212 Ma; 31 kbar, 590-650°C) and blueschist facies metamorphism in the Qinling belt. The systematic increasing peak pressure condition and decreasing peak temperature condition from the Odesan to Dabie-Sulu belt, may be due to the increase in the depth of slab break-off towards west, which might be related to the increase of the amounts of subducted oceanic slab towards west. However, after the slab break-off in the Dabie-Sulu area, the depth of slab break

Petrogenesis of Late Jurassic granodiorites from Gutian, Fujian Province, South China: Implications for multiple magma sources and origin of porphyry Cu-Mo mineralization

NASA Astrophysics Data System (ADS)

Li, Bin; Jiang, Shao-Yong; Lu, An-Huai; Lai, Jian-Qing; Zhao, Kui-Dong; Yang, Tao

2016-11-01

The Gutian porphyry Cu-Mo deposit is a newly proved porphyry copper deposit in the coastal South China associated with granodioritic porphyries. In this study, zircon U-Pb ages and Hf isotope data, as well as geochemical and Sr-Nd-Pb-Re-Os isotopic compositions, are reported for these intrusions and minerals. Both zircon U-Pb and molybdenite Re-Os dating suggest that the Gutian granodiorite porphyries and related mineralization formed at 160 Ma. The Gutian granodiorites show a low-Mg adakitic geochemical affinity, with relatively high K2O but low Cr and Ni contents. These rocks have initial (87Sr/86Sr)i ratios of 0.7085 to 0.7097, negative εNd(t) values (- 12.5 to - 7.8), (206Pb/204Pb)t ratios of 18.048 to 18.241, (207Pb/204Pb)t ratios of 15.609 to 15.628, and (208Pb/204Pb)t ratios of 38.494 to 38.667. Zircons from the granodiorites have negative εHf(t) values of - 15.7 to - 8.5, which are close to those of Cathaysia crust-derived melts. Geochemical and Sr-Nd-Pb-Hf isotopic compositions suggest that they may be derived from Late Jurassic thickened juvenile lower crust. These lower crustal magma sources may not only contain pre-Proterozoic basement rocks, but also involve Triassic and Middle-Late Jurassic arc magmas within the lower crust, which were likely derived from an enriched mantle source associated with paleo-Pacific Plate subduction from the Middle to Late Jurassic. The Gutian ore-related granodiorites represent a new example for significant contributions of ancient subduction melts and enriched mantle-derived sources for porphyry-type magmatism and Cu-Mo mineralization, which occurred in response to an arc regime during the Middle to Late Jurassic in South China. Supplemental Table S2. Hf isotopic compositions of zircons from the studied rocks from the Gutian porphyry deposit in South China. Supplemental Table S3. Statistics for zircon U-Pb ages and Hf isotope compositions from Gutian granodiorites in South China Supplemental Table S4. Major element (wt

Magnetic Properties of the Rivers Feeding the South China Sea: a Critical Step for Understanding the Paleo-Marine Records.

NASA Astrophysics Data System (ADS)

Kissel, C.; Liu, Z.; Wandres, C.

2014-12-01

In order to use the magnetic properties of marine sediments as a tracer for past changes in the precipitation rate on land and in oceanic water masses transport and exchanges in the South China Sea, we identify and characterize the different sources of the detrital fraction among which the magnetic particles. This work is presently conducted in the framework of the Franco-Chinese LIA-MONOCL Thanks to the Westpac project, we had access to sediments collected in the deltas of the main rivers feeding the South China Sea from about 25°N to the equator. This is represented on the Asian continent by the Pearl river, the Red River, the Mekong river, by Malaysia, Sumatra and Borneo regions with minor rivers but also contributing to the South China Sea, and finally by Luzon and Taiwan. The geological formations contributing to the river sediment discharges are different from one catchment basin to another as well as the present climatic conditions. The magnetic analyses consist in the analysis of low-field magnetic susceptibility, ARM acquisition and decay, IRM acquisition and decay, back-field acquisition, thermal demagnetization of 3-axes IRM, hysteresis parameters, and FORC diagrams. The obtained parameters all together allow us to define the nature of the magnetic grains and their grain size distribution when magnetite is dominant. Some degree of variability is observed at the river mouths, illustrating different geological sources at the local/regional scale. As an average, it appears that the Southern basin of the South China Sea is surrounded by regions richer in high coercivity magnetic minerals than the northern basin. This mineral is identified as hematite while magnetites (and sulfides) are more abundant in the north. These results are complementary to the clay mineral assemblages previously determined on the same samples. The first steps of a similar study conducted on marine core-tops well distributed in the South China Sea will also be illustrated.

First characterization of bacterial pathogen, Vibrio alginolyticus, for Porites andrewsi White syndrome in the South China Sea.

PubMed

Zhenyu, Xie; Shaowen, Ke; Chaoqun, Hu; Zhixiong, Zhu; Shifeng, Wang; Yongcan, Zhou

2013-01-01

White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown. A transmission experiment was performed on P. andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm(2) d(-1) with a mean of 5.40 ± 3.34 cm(2) d(-1) (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch's postulates for establishing causality. Following exposure to bacterial concentrations of 10(5) cells mL(-1), the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus . This is the first report of V. alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V. alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea.

First Characterization of Bacterial Pathogen, Vibrio alginolyticus, for Porites andrewsi White Syndrome in the South China Sea

PubMed Central

Chaoqun, Hu; Zhixiong, Zhu; Shifeng, Wang; Yongcan, Zhou

2013-01-01

Background White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown. Methodology/Principal Findings A transmission experiment was performed on P . andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm2 d-1 with a mean of 5.40 ± 3.34 cm2 d-1 (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch’s postulates for establishing causality. Following exposure to bacterial concentrations of 105 cells mL-1, the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus . Conclusion/Significance This is the first report of V . alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V . alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea. PMID:24086529

Bibliometric analysis of scientific publications in transplantation journals from Mainland China, Japan, South Korea and Taiwan between 2006 and 2015.

PubMed

Pu, Qiang-Hong; Lyu, Qiu-Ju; Su, Huai-Yu

2016-08-03

The aim of this study is to compare the quantity and quality of scientific publications in transplantation fields that were written by researchers from Mainland China, Japan, South Korea and Taiwan in the East Asia region. East Asia. Articles except editorials, conference abstracts, letters, news and corrections published in 25 transplantation journals from 2006 to 2015 were screened with the Web of Science database. The number of total and annual articles, article types (study design and transplantation site), impact factor, citations and articles in the high-impact journals was determined to assess the quantity and quality of transplantation research from East Asia. The correlation of socioeconomic factors and annual publications was also analysed. From 2006 to 2015, there were 47 141 articles published in transplantation journals, of which researchers from Japan published 3694 articles, followed by Mainland China, South Korea and Taiwan with 2778, 1643 and 951 articles, respectively. Similar trends were observed in accumulated impact factor, accumulated citations, articles in the high-impact journals and articles on transplantation site. Publications from Japan had the highest average impact factor and citation, while those from Mainland China had the lowest. Additionally, in terms of study design, authors from Mainland China contributed to most clinical trials and randomised controlled trials, but authors from Japan contributed to most case reports. The annual numbers of articles from Mainland China and South Korea increased linearly (p<0.05), but those from Japan and Taiwan remained stable for the period studied. The annual numbers of articles from Mainland China and South Korea were positively correlated with gross domestic product (p<0.05). Transplantation research productivity in East Asia is highly skewed, with gross domestic product having a significant positive correlation. Mainland China still lags far behind Japan in most bibliometric indicators

Bibliometric analysis of scientific publications in transplantation journals from Mainland China, Japan, South Korea and Taiwan between 2006 and 2015

PubMed Central

Lyu, Qiu-Ju; Su, Huai-Yu

2016-01-01

Objectives The aim of this study is to compare the quantity and quality of scientific publications in transplantation fields that were written by researchers from Mainland China, Japan, South Korea and Taiwan in the East Asia region. Settings East Asia. Participants and outcome measures Articles except editorials, conference abstracts, letters, news and corrections published in 25 transplantation journals from 2006 to 2015 were screened with the Web of Science database. The number of total and annual articles, article types (study design and transplantation site), impact factor, citations and articles in the high-impact journals was determined to assess the quantity and quality of transplantation research from East Asia. The correlation of socioeconomic factors and annual publications was also analysed. Results From 2006 to 2015, there were 47 141 articles published in transplantation journals, of which researchers from Japan published 3694 articles, followed by Mainland China, South Korea and Taiwan with 2778, 1643 and 951 articles, respectively. Similar trends were observed in accumulated impact factor, accumulated citations, articles in the high-impact journals and articles on transplantation site. Publications from Japan had the highest average impact factor and citation, while those from Mainland China had the lowest. Additionally, in terms of study design, authors from Mainland China contributed to most clinical trials and randomised controlled trials, but authors from Japan contributed to most case reports. The annual numbers of articles from Mainland China and South Korea increased linearly (p<0.05), but those from Japan and Taiwan remained stable for the period studied. The annual numbers of articles from Mainland China and South Korea were positively correlated with gross domestic product (p<0.05). Conclusions Transplantation research productivity in East Asia is highly skewed, with gross domestic product having a significant positive correlation

Conservation of cultural heritage in minority ethnic regions in northwestern china—an exploration at Kuqa, Xinjiang

NASA Astrophysics Data System (ADS)

Wu, N.; Zhang, X.

2015-08-01

Kuqa, Xinjiang, is located at northwestern inland china. Traditionally a bridge between eastern and western civilizations, Kuqa had a history of cultural fusion and was left with abundant cultural heritage. As population increase, economic growth and social changes occurred, spontaneous renovation of the old city was affected, in which street fabric and scenes underwent damages. The paper demonstrates attempts made in various projects to achieve conservation of cultural heritage in agreement with economic development and improvement of living condition. The lessons learnt in these projects will be of value to development of other historic cities, especially in minority ethnic regions in China.

A new species of Pectinaria (Annelida, Pectinariidae), with a key to pectinariids from the South China Sea.

PubMed

Zhang, Jinghuai; Qiu, Jian-Wen

2017-01-01

Pectinariidae is a family of polychaetes building unique ice-cream cone shaped sandy tubes. Pectinaria torquata sp. n. (Pectinariidae) is described from the coastal waters of the northern South China Sea. This new species can be distinguished from all other 25 recognized species in the genus by a combination of characters: 16 chaetigers; 26-32 cirri in the cephalic veil; 11-12 pairs of cephalic spines; uncini with major teeth arranged in two rows, each with 7-8 major teeth; presence of a dorsal posterior lobe on segments 2 and 20; 4-5 pairs of curved scaphal hooks; and an anal flap with a crenulated margin. A key to all recognized pectinariids in the South China Sea is provided.

Phylogeographic heterogeneity of the brown macroalga Sargassum horneri (Fucaceae) in the northwestern Pacific in relation to late Pleistocene glaciation and tectonic configurations.

PubMed

Hu, Zi-Min; Uwai, Shinya; Yu, Shen-Hui; Komatsu, Teruhisa; Ajisaka, Tetsuro; Duan, De-Lin

2011-09-01

Pleistocene glacial oscillations and associated tectonic processes are believed to have influenced the historical abundances and distribution of organisms in the Asia Northwest Pacific (ANP). Accumulating evidence indicates that factors shaping tempospatial population dynamics and distribution patterns of marine taxa vary with biogeographical latitude, pelagic behaviour and oceanographic regimes. To detect what kinds of historical and contemporary factors affected genetic connectivity, phylogeographic profiles of littoral macroalga Sargassum horneri in the ANP were analysed based on mitochondrial (Cox3) and chloroplast (rbcL) data sets. Five distinct clades were recovered. A strong signature of biogeographical structure was revealed (Φ(CT) = 0.487, P < 0.0001) derived from remarkable differentiation in clade distribution, as clade I is restricted to Chinese marginal seas (Yellow-Bohai Sea, East China Sea and South China Sea), whereas clades II-V are discontinuously scattered around the main Islands of Japan. Furthermore, two secondary contact regions were identified along the south Japan-Pacific coastline. This significant differentiation between the two basins may reflect historical glacial isolation in the northwestern Pacific, which is congruent with the estimates of clade divergence and demographic expansion during the late Quaternary low sea levels. Analysis of molecular variance and the population-pair statistic F(ST) also revealed significant genetic structural differences between Chinese marginal seas and the Japanese basin. This exceptional phylogeographic architecture in S. horneri, initially shaped by historical geographic isolation during the late Pleistocene ice age and physical biogeographical barriers, can be complicated by oceanographic regimes (ocean surface currents) and relocating behaviour such as oceanic drifting. © 2011 Blackwell Publishing Ltd.

Mid-Neolithic Exploitation of Mollusks in the Guanzhong Basin of Northwestern China: Preliminary Results

PubMed Central

Li, Fengjiang; Wu, Naiqin; Lu, Houyuan; Zhang, Jianping; Wang, Weilin; Ma, Mingzhi; Zhang, Xiaohu; Yang, Xiaoyan

2013-01-01

Mollusk remains are abundant in archaeological sites in the Guanzhong Basin of Northwestern China, providing good opportunities for investigations into the use of mollusks by prehistoric humans. Here we report on freshwater gastropod and bivalve mollusks covering the time interval from about 5600 to 4500 cal. yrs BP from sites of Mid-Late Neolithic age. They are identified as Cipangopaludina chinensis and Unio douglasiae, both of which are currently food for humans. The shells are well preserved and have no signs of abrasion. They are all freshwater gastropods and bivalves found in pits without water-reworked deposits and have modern representatives which can be observed in rivers, reservoirs, and paddy fields in the studied region. Mollusk shells were frequently recovered in association with mammal bones, lithic artifacts, and pottery. These lines of evidence indicate that the mollusks are the remains of prehistoric meals. The mollusk shells were likely discarded into the pits by prehistoric humans after the flesh was eaten. However, these mollusk remains may not have been staple food since they are not found in large quantities. Mollusk shell tools and ornaments are also observed. Shell tools include shell knives, shell reaphooks and arrowheads, whereas shell ornaments are composed of pendants and loops. All the shell tools and ornaments are made of bivalve mollusks and do not occur in large numbers. The finding of these freshwater mollusk remains supports the view that the middle Holocene climate in the Guanzhong Basin may have been warm and moist, which was probably favorable to freshwater mollusks growing and developing in the region. PMID:23544050

Analysis of the geological structure and tectonic evolution of Xingning-Jinghai sag in deep water area, northern South China Sea

NASA Astrophysics Data System (ADS)

Han, Xiaoying; Ren, Jianye; Lin, Zi; Yang, Linlong

2015-04-01

Recent years, oil and gas exploration of the Pearl River Mouth Basin in the northern margin of South China Sea continuously achieved historic breakthroughs. The Xingning-Jinghai sag, which is located in southeast of the Pearl River Mouth Basin, is a deep-water sag with a great exploration potential. Its tectonic evolution is extremely complex. It experienced Mesozoic subduction to Cenozoic intra-continental rifting background, and finally evolved into a deep-water sag of the northern continental margin of South China Sea. The geological characteristics and the tectonic evolution of Xingning-Jinghai sag was closely related to the process of formation and evolution of the passive continental margin of the northern South China Sea. It is confirmed by many geophysical data that compared with adjacent Chaoshan depression, the crustal thickness of Xingning-Jinghai sag was rapidly thinning, and it developed detachment faults with later magmatic intrusion. The development of detachment faults have dynamic significance for the spreading of the South China Sea. Based on the seismic geological interpretation of 2D seismic data in the study area, the characteristics of detachment fault and supra-detachment basin have been proposed in this study. The characteristics of the detachment fault are low angle and high ratio between heave and throw. The geometry of the detachment fault is a typical lisric shape, with the dip of fault decreasing generally from the seismic profile. The detachment basin where sediments are not deposited over a tilting hanging-wall block but onto a tectonically exhumed footwall which is different from the typical half graben basin. Seismic profiles indicate two different structural styles in the east and west part of Xingning-Jinghai sag. In the west of the sag, there developed two large detachment faults, which control their detachment basin systems and the typical H block, and the two detachment faults are dipping landward and seaward, respectively. In

Methylmercury in fish from the South China Sea: geographical distribution and biomagnification.

PubMed

Zhu, Aijia; Zhang, Wei; Xu, Zhanzhou; Huang, Liangmin; Wang, Wen-Xiong

2013-12-15

We conducted a large-scale investigation of methylmercury (MeHg) in a total of 628 marine wild fish covering 46 different species collected from the South China Sea between 2008 and 2009. Biological and ecological characteristics such as size (length and wet weight), feeding habit, habitat, and stable isotope (δ(15)N) were examined to explain MeHg bioaccumulation in marine fish and their geographical distribution. MeHg levels in the muscle tissues of the 628 individuals ranged from 0.010 to 1.811 μg/g dry wt. Log10MeHg concentration was significantly related to their length and wet weight. Feeding habit and habitat were the primary factors influencing MeHg bioaccumulation. Demersal fish were more likely to be contaminated with MeHg than the epipelagic and mesopelagic varieties. Linear relationships were obtained between Log10(MeHg) and δ(15)N only for one location, indicating that biomagnification was site-specific. Results from this study suggest that dietary preference and trophic structure were the main factors affecting MeHg bioaccumulation in marine fish from the South China Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recent land cover changes and sensitivity of the model simulations to various land cover datasets for China

NASA Astrophysics Data System (ADS)

Chen, Liang; Ma, Zhuguo; Mahmood, Rezaul; Zhao, Tianbao; Li, Zhenhua; Li, Yanping

2017-08-01

Reliable land cover data are important for improving numerical simulation by regional climate model, because the land surface properties directly affect climate simulation by partitioning of energy, water and momentum fluxes and by determining temperature and moisture at the interface between the land surface and atmosphere. China has experienced significant land cover change in recent decades and accurate representation of these changes is, hence, essential. In this study, we used a climate model to examine the changes experienced in the regional climate because of the different land cover data in recent decades. Three sets of experiments are performed using the same settings, except for the land use/cover (LC) data for the years 1990, 2000, 2009, and the model default LC data. Three warm season periods are selected, which represented a wet (1998), normal (2000) and a dry year (2011) for China in each set of experiment. The results show that all three sets of land cover experiments simulate a warm bias relative to the control with default LC data for near-surface temperature in summertime in most parts of China. It is especially noticeable in the southwest China and south of the Yangtze River, where significant changes of LC occurred. Deforestation in southwest China and to the south of Yangtze River in the experiment cases may have contributed to the negative precipitation bias relative to the control cases. Large LC changes in northwestern Tibetan Plateau for 2000 and 2009 datasets are also associated with changes in surface temperature, precipitation, and heat fluxes. Wind anomalies and energy budget changes are consistent with the precipitation and temperature changes.

The characteristics of heat flow in the Shenhu gas hydrate drilling area, northern South China Sea

NASA Astrophysics Data System (ADS)

Xu, Xing; Wan, Zhifeng; Wang, Xianqing; Sun, Yuefeng; Xia, Bin

2016-12-01

Marine heat flow is of great significance for the formation and occurrence of seabed oil, gas and gas hydrate resources. Geothermal gradient is an important parameter in determining the thickness of the hydrate stability zone. The northern slope of the South China Sea is rich in gas hydrate resources. Several borehole drilling attempts were successful in finding hydrates in the Shenhu area, while others were not. The failures demand further study on the distribution regularities of heat flow and its controlling effects on hydrate occurrence. In this study, forty-eight heat flow measurements are analyzed in the Shenhu gas hydrate drilling area, located in the northern South China Sea, together with their relationship to topography, sedimentary environment and tectonic setting. Canyons are well developed in the study area, caused mainly by the development of faults, faster sediment supply and slumping of the Pearl River Estuary since the late Miocene in the northern South China Sea. The heat flow values in grooves, occurring always in fault zones, are higher than those of ridges. Additionally, the heat flow values gradually increase from the inner fan, to the middle fan, to the external fan subfacies. The locations with low heat flow such as ridges, locations away from faults and the middle fan subfacies, are more conducive to gas hydrate occurrence.

Taxonomic research on deep-sea macrofauna in the South China Sea using the Chinese deep-sea submersible Jiaolong.

PubMed

Li, Xinzheng

2017-07-01

This paper reviews the taxonomic and biodiversity studies of deep-sea invertebrates in the South China Sea based on the samples collected by the Chinese manned deep-sea submersible Jiaolong. To date, 6 new species have been described, including the sponges Lophophysema eversa, Saccocalyx microhexactin and Semperella jiaolongae as well as the crustaceans Uroptychus jiaolongae, Uroptychus spinulosus and Globospongicola jiaolongi; some newly recorded species from the South China Sea have also been reported. The Bathymodiolus platifrons-Shinkaia crosnieri deep-sea cold seep community has been reported by Li (2015), as has the mitochondrial genome of the glass sponge L. eversa by Zhang et al. (2016). The population structures of two dominant species, the shrimp Shinkaia crosnieri and the mussel Bathymodiolus platifrons, from the cold seep Bathymodiolus platifrons-Shinkaia crosnieri community in the South China Sea and the hydrothermal vents in the Okinawa Trough, were compared using molecular analysis. The systematic position of the shrimp genus Globospongicola was discussed based on 16S rRNA gene sequences. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Airborne Bacterial Communities in Three East Asian Cities of China, South Korea, and Japan.

PubMed

Lee, Jae Young; Park, Eun Ha; Lee, Sunghee; Ko, GwangPyo; Honda, Yasushi; Hashizume, Masahiro; Deng, Furong; Yi, Seung-Muk; Kim, Ho

2017-07-17

The global diversity of airborne bacteria has not yet been studied, despite its importance in human health and climate change. Here, we focused on the diversity of airborne bacteria and their correlations with meteorological/environmental conditions in China, South Korea, and Japan. Beijing (China) had more diverse airborne bacteria, followed by Seoul (South Korea) and Nagasaki (Japan), and seasonal variations were observed. Beijing and Seoul had more diverse airborne bacteria during the winter, whereas Nagasaki showed greater diversity during the summer. According to principal component analysis and Bray-Curtis similarity, higher similarity was observed between Beijing and Seoul than between Seoul and Nagasaki during all seasons except summer. Among meteorological/environmental variables, temperature and humidity were highly correlated with the diversity of airborne bacteria on the measurement day, whereas wind speeds and the frequency of northwest winds were highly correlated for 2-3-day moving averages. Thus, proximity and resuspension could enhance bacterial diversity in East Asian cities.

Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

NASA Astrophysics Data System (ADS)

Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

2014-06-01

Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048-1079 and AD 1838-2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830-1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem.

Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

PubMed Central

Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

2014-01-01

Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048–1079 and AD 1838–2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830–1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

Spatio-temporal variations in the siphonophore community of the northern South China Sea

NASA Astrophysics Data System (ADS)

Li, Kaizhi; Yin, Jianqiang; Huang, Liangmin; Lian, Shumin; Zhang, Jianlin

2013-03-01

To understand how hydrological and biological factors affect near- to off-shore variations in the siphonophore community, we sampled zooplankton at 82 stations in the northern South China Sea during summer, winter, and spring. Forty-one species of siphonophore were collected by vertical trawling. The species richness of siphonophores increased from the nearshore to offshore regions in all three seasons of investigation, with maximum richness in summer and minimum richness in winter. The abundance of siphonophores was also higher in summer than in spring and winter, concentrated in the nearshore region in the warm season and scattered in the offshore region in the cold season. Four siphonophore groups were classified according to the frequency of occurrence: nearshore, near-offshore, offshore, and tropical pelagic. Among them, the nearshore group had higher abundance nearshore compared with the offshore. The tropical pelagic group had higher species number offshore than nearshore. Spatial and temporal fluctuations in taxonomic composition and abundance of siphonophores were due to the influence of the coastal upwelling and surface ocean currents of the South China Sea, driven by the East Asia monsoonal system.

Antifouling potentials of eight deep-sea-derived fungi from the South China Sea.

PubMed

Zhang, Xiao-Yong; Xu, Xin-Ya; Peng, Jiang; Ma, Chun-Feng; Nong, Xu-Hua; Bao, Jie; Zhang, Guang-Zhao; Qi, Shu-Hua

2014-04-01

Marine-derived microbial secondary metabolites are promising potential sources of nontoxic antifouling agents. The search for environmentally friendly and low-toxic antifouling components guided us to investigate the antifouling potentials of eight novel fungal isolates from deep-sea sediments of the South China Sea. Sixteen crude ethyl acetate extracts of the eight fungal isolates showed distinct antibacterial activity against three marine bacteria (Loktanella hongkongensis UST950701-009, Micrococcus luteus UST950701-006 and Pseudoalteromonas piscida UST010620-005), or significant antilarval activity against larval settlement of bryozoan Bugula neritina. Furthermore, the extract of Aspergillus westerdijkiae DFFSCS013 displayed strong antifouling activity in a field trial lasting 4 months. By further bioassay-guided isolation, five antifouling alkaloids including brevianamide F, circumdatin F and L, notoamide C, and 5-chlorosclerotiamide were isolated from the extract of A. westerdijkiae DFFSCS013. This is the first report about the antifouling potentials of metabolites of the deep-sea-derived fungi from the South China Sea, and the first stage towards the development of non- or low-toxic antifouling agents from deep-sea-derived fungi.

Boron isotopic composition of Porites corals over the past 500 years in the South China Sea: Evaluating the potential controlling factors

NASA Astrophysics Data System (ADS)

Wang, Tzu-Hao; You, Chen-Feng; Liu, Yi; Chung, Chuan-Hsiung; Liu, Hou-Chun

2016-04-01

As the largest marginal sea in the East Asia, the South China Sea is sensitive to the environmental changes both in Asia landmass and western Pacific Ocean. Thus, the cause-consequence feedback systems between the seawater chemistry and environmental change in the South China Sea encompass various interactions and controlling factors on different spatial and temporal scales. Global and regional (e.g., continental sources, and the East Asian monsoon system) factors may have a simultaneous impact on the coral records. However, the representative meanings of coral records in the South China Sea are still poorly understood. Here we present an age-controlled coral boron isotopic (δ11B) record in the Xisha Islands, the northern South China Sea, from AD 1466 to AD 1960. We applied micro-sublimation technique and MC-ICP-MS measurement to provide a low-blank and highly precise δ11B measurement. The δ11B values of the coral specimens varied from 20.8‰ to 26.0‰ which the variation is larger than the observation in the western Pacific Ocean within the same periods. The δ11B data showed a gradual increase during AD 1466-1829 and a relatively sharp decline then until AD 1960. The anthropogenic emission of CO2 may explain the decline of coral-inferred seawater pH over the past 200 years but not for the period of AD 1466-1829. An evaluated correlation was observed between the variation of coral δ11B values and the monsoon-associated upwelling phenomenon, which implies a significant influence of the Asian monsoon system on boron geochemistry in the northern SCS. This study will provide a comprehensive discussion regarding the potential factors controlling the boron isotopic composition in the northern South China Sea over the past 500 years.

[Field resistance of Phytophthora melonis to metalaxyl in South China].

PubMed

Wu, Yongguan; Lu, Shaofeng; Huang, Siliang; Fu, Gang; Chen, Liang; Xie, Dasen; Li, Qiqin; Cen, Zhenlu

2011-08-01

Phytophthora melonis is the casual agent of wax gourd and cucumber Phytophthora blight which becomes a constraint for sustainable production of the related crops. Metalaxyl is one of the principal fungicides for controlling the disease now. The objectives of the present study were: (1) to investigate the baseline sensitivity and field resistance of P. melonis to metalaxyl in South China; (2) to test the occurrence of metalaxyl-resistant mutants from metalaxyl-sensitive wild type strains exposed to the fungicide; and (3) to monitor the development of metalaxyl resistance in P. melonis population. Over 400 samples of wax gourd and cucumber Phytophthora blight were collected from Guangxi Zhuang Autonomous Region and Guangdong province during 2007-2010, and 193 strains of P. melonis were isolated and purified. The sensitivity of the isolated strains to metalaxyl was tested using mycelial growth rate method in vitro and floating-leaf-disk method in vivo, respectively. The metalaxyl-sensitive strains were induced on PDA plates containing 10 microg/mL metalaxyl. The sensitive, moderately resistant and resistant strains were recorded as 29.0% , 18.1% and 52.8%, respectively, among 193 tested strains. The frequency and level of resistance of P. melonis from Guangdong were higher than that from Guangxi. The strains from cucumber was generally more resistant to metalaxyl than those from wax gourd. The metalaxyl-resistant strains were frequently detected as predominant populations in most of the sampling sites and the highest resistance index (4226.9) was confirmed. Metalaxyl-resistant (M1r) mutants could be isolated from approximately 60% of the sensitive wild-type strains. The resistance level of the M mutants was 189-407 times higher than that of their sensitive parental strains. The EC50 values of 9 sensitive strains from a sampling site without a record of phenylamide fungicide application ranged from 0.0429 to 0.5461 microg/mL. Their mean EC50 value (0.3200 +/- 0

[Distribution and sources of polycyclic aromatic hydrocarbons in sediments from rivers of Pearl River Delta and its nearby South China Sea].

PubMed

Luo, Xiao-Jun; Chen, She-Jun; Mai, Bi-Xian; Zeng, Yong-Ping; Sheng, Guo-Ying; Fu, Jia-Mo

2005-07-01

Polycyclic aromatic hydrocarbons (PAHs) are measured in surface sediments from rivers and estuary of Pearl River Delta and its nearby South China Sea. Total PAH concentration varied from 255.9 - 16 670.3 ng/g and a moderate to low level compare to relevant areas worldwide. The order of PAHs concentration in sediments was: rivers of Pearl River Delta > estuary > South China Sea, and the most significant PAH contamination was at Guangzhou channel of Zhujiang river. A decrease trend for PAHs concentration with distance from estuary to open sea can be sees in South China Sea. Coal and biomass combustion is the major source of PAHs in nearshore of South China Sea, and petroleum combustion is the main source of pyrolytic PAHs in rivers and estuary of Pearl River Delta according to PAHs diagnostic ratios. Petroleum PAHs are revealed have a high contribution to PAHs in Xijiang River, estuary and some stations in Zhujiang River. A comparison of data from study in 1997 with data from present study indicates that there is no clear change in the PAH concentration over time but the source of PAHs in Pearl River Delta have been change from a main coal combustion to petroleum combustion and being reflect in the sediments in rivers and estuary of Pearl River Delta where there have high sedimentation rate.

Coverage and factors associated with influenza vaccination among kindergarten children 2-7 years old in a low-income city of north-western China (2014-2016)

PubMed Central

Yang, Juan; Han, Wei; Lei, Youju; Feng, Huaxiang; Zhu, Xiaoyun; Li, Yanming; Yu, Hongjie; Feng, Luzhao; Shi, Yan

2017-01-01

Influenza vaccination has been shown to be the most effective preventive measure to reduce influenza virus infection and its related morbidity and mortality. Young children aged 6–59 months are recommended as one of the priority groups for seasonal influenza vaccination in China. Our study was conducted to evaluate the level of influenza vaccination coverage during 2014–15 and 2015–16 influenza seasons among kindergarten children aged 2–7 years in Xining, a low-income city of north-western China, and to explore potential factors for noncompliance associated with influenza vaccination. The coverage rate of influenza vaccination was 12.2% (95 CI: 10.6–14.2%) in 2014–15 and 12.8% (95 CI: 11.1–14.7%) in 2015–16. The low coverage rate was found to be primarily associated with the lack of knowledge about influenza vaccine in children’s parents. The most common reason for vaccine declination was the concern about adverse reactions of vaccine. Therefore tailored information should be provided by clinician and public health doctors for targeted groups through effective methods to improve public understanding of vaccination. PMID:28749980

Convective Systems Over the South China Sea: Cloud-Resolving Model Simulations

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Shie, C.-L.; Johnson, D.; Simpson, J.; Braun, S.; Johnson, R.; Ciesielski, P. E.; Starr, David OC. (Technical Monitor)

2002-01-01

The South China Sea Monsoon Experiment (SCSMEX) was conducted in May-June 1998. One of its major objectives is to better understand the key physical processes for the onset and evolution of the summer monsoon over Southeast Asia and southern China. Multiple observation platforms (e.g., upper-air soundings, Doppler radar, ships, wind profilers, radiometers, etc.) during SCSMEX provided a first attempt at investigating the detailed characteristics of convective storms and air pattern changes associated with monsoons over the South China Sea region. SCSMEX also provided rainfall estimates which allows for comparisons with those obtained from the Tropical Rainfall Measuring Mission (TRMM), a low earth orbit satellite designed to measure rainfall from space. The Goddard Cumulus Ensemble (GCE) model (with 1-km grid size) is used to understand and quantify the precipitation processes associated with the summer monsoon over the South China Sea. This is the first (loud-resolving model used to simulate precipitation processes in this particular region. The GCE-model results captured many of the observed precipitation characteristics because it used a fine grid size. For example, the temporal variation of the simulated rainfall compares quite well to the sounding-estimated rainfall variation. The time and domain-averaged temperature (heating/cooling) and water vapor (drying/ moistening) budgets are in good agreement with observations. The GCE-model-simulated rainfall amount also agrees well with TRMM rainfall data. The results show there is more evaporation from the ocean surface prior to the onset of the monsoon than after the on-et of monsoon when rainfall increases. Forcing due to net radiation (solar heating minus longwave cooling) is responsible for about 25% of the precipitation in SCSMEX The transfer of heat from the ocean into the atmosphere does not contribute significantly to the rainfall in SCSMEX. Model sensitivity tests indicated that total rain production is

Drug reimbursement decision-making in Thailand, China, and South Korea.

PubMed

Ngorsuraches, Surachat; Meng, Wei; Kim, Bo-Yeon; Kulsomboon, Vithaya

2012-01-01

To provide a comparison of national drug reimbursement decision-making, including an update of economic evaluation roles and barriers, in Thailand, China, and South Korea. Documentary reviews supplemented by experiences of policymakers. National health insurance policy in all the three countries has been developed toward coverage for all. It leads to higher health-care expenditures and requires a good reimbursement system for health-care services, including drugs. Drug reimbursement decision-making in these countries is to develop a reimbursement list with the help of various committees having different roles. Primarily, they assess the clinical and safety evidence. Economic evidence, including budget impact and pharmacoeconomic evaluation, has also been very important for their reimbursement decision-making. This evidence is sometimes used in negotiation mechanism, which allows pharmaceutical companies to lower their drug prices and leads to lower overall drug expenditures. Several common barriers, for example, human capacity and data availability, for obtaining economic evidence in all the three countries, however, still exist. Drug reimbursement decision-making in Thailand, China, and South Korea is in its transition period. It seems to run in the same direction, for example, guideline development and pharmacoeconomic evaluation agency establishment. Pharmacoeconomic evaluation plays important roles in the efficiency of drug reimbursement decision-making, even though there are several barriers to be overcome. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Developing an Age Model for the Cryogenian: the South China perspective

NASA Astrophysics Data System (ADS)

Condon, D. J.; Zhu, M.; Macdonald, F. A.; Tapster, S.

2014-12-01

The Neoproterozoic stratigraphic record of South China contains distributed volcanic ash beds, which can be dated and used to provide a backbone for Cryogenian and Ediacaran 'age models'. When integrated with geochemical and paleontological data, both locally and from other regions, these successions inform our understanding of environmental and biological change from these intervals. At present the South China stratigraphy provides the dates that best approximate the termination of the Marinoan glaciation (ca. 635 Ma, U-Pb single zircon isotope dilution1) from a dated volcanic ash bed that occurs in the cap carbonate sequence (Doushantuo Formation) which directly overlies the Nantuo Tillite (Marinoan glaciation equivalent). A number of other ash beds have been documented in both the Nantuo Tillite and throughout the Datangpo Formation (pre-Marinoan non-glacial succession) and have been variably dated using U-Pb microbeam and multi-grain isotope dilution studies2-4. These published data sets have produced dates that have uncertainties on the order of 4 Myr but are built upon single-analyses data points, which have uncertainties on the order of 10 Myr or greater thereby limiting their utility for assessing temporal relationship with other dated section. We present new U-Pb single zircon isotope dilution geochronology data from a suite of samples from the Datangpo, Nantuo and Doushantuo Formations. New dates from the base of the Datangpo Formation confirm a ca. 660 Ma end to the Sturtian glacial epoch, which is represented by underlying glacial deposits. Additional dates from ash beds from the Datangpo Formation and the lower Nantuo Tillite will refine the duration of the Cryogenian non-glacial interlude and Marinoan glaciation as recorded in South China. Combined with published data from Namibia, Australia and Canada, these new data will permit the development of a more highly resolved age model for the Cryogenian, enabling estimation of duration and synchronicity

Comparative study on the antioxidant activities of extracts of Coreopsis tinctoria flowering tops from Kunlun Mountains, Xinjiang, north-western China.

PubMed

Yao, Xincheng; Gu, Chengzhi; Tian, Liping; Wang, Xinbing; Tang, Hui

2016-01-01

Coreopsis tinctoria flowering tops (CTFs) from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study aims to assess the antioxidant activities and total phenolic, flavonoid and proanthocyanidin contents of various solvent extracts of CTF. CTF was extracted using n-hexane, chloroform, ethyl acetate, n-butanol, 75% aqueous ethanol (AEE) and water. The antioxidant activities of the CTF extracts were investigated through DPPH, ABTS, *OH, *O2(-), total antioxidant capacity and reducing power assays. The results showed that n-butanol extract showed the highest contents of total phenols and flavonoids, with DPPH, ABTS and *OH radical-scavenging activities with IC50 values of 134, 90.72 and 13.8 μg mL(-1), respectively. The AEE demonstrated the strongest DPPH and ABTS radical-scavenging activities, with IC50 values of 103 and 75.16 μg mL(-1), respectively. Given its high antioxidant effect, CTF is a good source of natural antioxidants or functional food materials.

Phylogenetic Analysis and Pathogenicity Assessment of the Emerging Recombinant Subgroup K of Avian Leukosis Virus in South China

PubMed Central

Zhao, Zijun; Rao, Mingzhang; Liao, Ming; Cao, Weisheng

2018-01-01

In recent years, cases of avian leukosis virus (ALV) infection have become more frequent in China. We isolated 6 ALV strains from yellow feather broiler breeders in south China from 2014 to 2016. Their full genomes were sequenced, compared, and analyzed with other reference strains of ALV. The complete genomic nucleotide sequences of GD150509, GD160403, GD160607, GDFX0601, and GDFX0602 were 7482 bp in length, whereas GDFX0603 was 7480 bp. They shared 99.7% to 99.8% identity with each other. Homology analysis showed that the gag, pol, long terminal repeats (LTRs), and the transmembrane region (gp37) of the env genes of the 6 viruses were well conserved to endogenous counterpart sequences (>97.8%). However, the gp85 genes displayed high variability with any known chicken ALV strains. Growth kinetics of DF-1 cells infected with the isolated ALV showed viral titers that were lower than those infected with the GD13 (ALV-A), CD08 (ALV-B), and CHN06 (ALV-J) on day 7 post-infection. The infected Specific-pathogen-free (SPF) chickens could produce continuous viremia, atrophy of immune organs, growth retardation and no tumors were observed. These subgroup ALVs are unique and may be common in south China. The results suggested that updating the control and eradication program of exogenous ALV for yellow feather broiler breeders in south China needs to be considered because of the emergence of the new subgroup viruses. PMID:29652854

Pork Preference for Consumers in China, Japan and South Korea

PubMed Central

Oh, S.-H.; See, M. T.

2012-01-01

Competition in global pork markets has increased as trade barriers have opened as a result of free trade agreements. Japanese prefer both loin and Boston butt, while Chinese prefer pork offal. Frozen pork has increased in terms of imports into China. Japanese consumers consider pork meat origin along with pork price when making purchase decisions. While the Chinese prefer a strong tasting pork product, South Korean consumers show very strong preferences to pork that is higher in fat. Therefore, South Korean consumers have a higher demand for pork belly and Boston butt. Consequently, the supply and demand of pork in Korea is hardly met, which means that importation of high fat parts is inevitable. In Korea there is lower preference toward low fat parts such as loin, picnic shoulder, and ham. During the economic depression in South Korea there have been observable changes in consumer preferences. There remains steep competition among the pork exporting countries in terms of gaining share in the international pork market. If specific consumer preferences would be considered carefully, there is the possibility to increase the amount of pork exported to these countries. PMID:25049488

A new species of Pectinaria (Annelida, Pectinariidae), with a key to pectinariids from the South China Sea

PubMed Central

Zhang, Jinghuai; Qiu, Jian-Wen

2017-01-01

Abstract Pectinariidae is a family of polychaetes building unique ice-cream cone shaped sandy tubes. Pectinaria torquata sp. n. (Pectinariidae) is described from the coastal waters of the northern South China Sea. This new species can be distinguished from all other 25 recognized species in the genus by a combination of characters: 16 chaetigers; 26–32 cirri in the cephalic veil; 11–12 pairs of cephalic spines; uncini with major teeth arranged in two rows, each with 7–8 major teeth; presence of a dorsal posterior lobe on segments 2 and 20; 4–5 pairs of curved scaphal hooks; and an anal flap with a crenulated margin. A key to all recognized pectinariids in the South China Sea is provided. PMID:28769730

Epidemiological survey of ticks and tick-borne pathogens in pet dogs in south-eastern China.

PubMed

Zhang, Jianwei; Liu, Qingbiao; Wang, Demou; Li, Wanmeng; Beugnet, Frédéric; Zhou, Jinlin

2017-01-01

To understand the epidemiology of tick infestation and tick-borne diseases in pet dogs in south-eastern China and to develop a reference for their prevention and treatment, we collected 1550 ticks parasitizing 562 dogs in 122 veterinary clinics from 20 cities of south-eastern China. Dogs were tested for common tick-borne pathogens; collected ticks were identified and processed for the detection of tick-borne pathogens. The use of an in vitro ELISA diagnostic kit for antibody detection (SNAP®4Dx® Plus) on dog sera found the infection rates with Borrelia burgdorferi sensu lato, Ehrlichia canis, and Anaplasma spp. to be 0.4%, 1.3% and 2.7%, respectively. By using a specific ELISA method, the infection rate with Babesia gibsoni was 3.9%. Rhipicephalus sanguineus sensu lato, Haemaphysalis longicornis and Rhipicephalus haemaphysaloides were the major tick species identified on pet dogs. PCR tests were conducted to detect five tick-borne pathogens in 617 ticks. The infection rate was 10.2% for E. canis, 3.4% for Anaplasma platys, 2.3% for B. gibsoni, 0.3% for B. burgdorferi s.l. and 0% for Babesia canis. Some ticks were co-infected with two (1.46%) or three pathogens (0.16%). These results indicate the infestation of pet dogs by ticks infected with tick-borne pathogens in south-eastern China, and the need for effective treatment and routine prevention of tick infestations in dogs. © J. Zhang et al., published by EDP Sciences, 2017.

Atmospheric Circulation Patterns over East Asia and Their Connection with Summer Precipitation and Surface Air Temperature in Eastern China during 1961-2013

NASA Astrophysics Data System (ADS)

Li, Shuping; Hou, Wei; Feng, Guolin

2018-04-01

Based on the NCEP/NCAR reanalysis data and Chinese observational data during 1961-2013, atmospheric circulation patterns over East Asia in summer and their connection with precipitation and surface air temperature in eastern China as well as associated external forcing are investigated. Three patterns of the atmospheric circulation are identified, all with quasi-barotropic structures: (1) the East Asia/Pacific (EAP) pattern, (2) the Baikal Lake/Okhotsk Sea (BLOS) pattern, and (3) the eastern China/northern Okhotsk Sea (ECNOS) pattern. The positive EAP pattern significantly increases precipitation over the Yangtze River valley and favors cooling north of the Yangtze River and warming south of the Yangtze River in summer. The warm sea surface temperature anomalies over the tropical Indian Ocean suppress convection over the northwestern subtropical Pacific through the Ekman divergence induced by a Kelvin wave and excite the EAP pattern. The positive BLOS pattern is associated with below-average precipitation south of the Yangtze River and robust cooling over northeastern China. This pattern is triggered by anomalous spring sea ice concentration in the northern Barents Sea. The anomalous sea ice concentration contributes to a Rossby wave activity flux originating from the Greenland Sea, which propagates eastward to North Pacific. The positive ECNOS pattern leads to below-average precipitation and significant warming over northeastern China in summer. The reduced soil moisture associated with the earlier spring snowmelt enhances surface warming over Mongolia and northeastern China and the later spring snowmelt leads to surface cooling over Far East in summer, both of which are responsible for the formation of the ECNOS pattern.

Assessing blue and green water utilisation in wheat production of China from the perspectives of water footprint and total water use

NASA Astrophysics Data System (ADS)

Cao, X. C.; Wu, P. T.; Wang, Y. B.; Zhao, X. N.

2014-08-01

The aim of this study is to estimate the green and blue water footprint (WF) and the total water use (TWU) of wheat crop in China in both irrigated and rainfed productions. Crop evapotranspiration and water evaporation loss are both considered when calculating the water footprint in irrigated fields. We compared the water use for per-unit product between irrigated and rainfed crops and analyzed the relationship between promoting the yield and conserving water resources. The national total and per-unit-product WF of wheat production in 2010 were approximately 111.5 Gm3 (64.2% green and 35.8% blue) and 0.968 m3 kg-1, respectively. There is a large difference in the water footprint of the per-kilogram wheat product (WFP) among different provinces: the WFP is low in the provinces in and around the Huang-Huai-Hai Plain, while it is relatively high in the provinces south of the Yangtze River and in northwestern China. The major portion of WF (80.9%) comes from irrigated farmland, and the remaining 19.1% is rainfed. Green water dominates the area south of the Yangtze River, whereas low green water proportions are found in the provinces located in northern China, especially northwestern China. The national TWU and total water use of the per-kilogram wheat product (TWUP) are 142.5 Gm3 and 1.237 m3 kg-1, respectively, containing approximately 21.7% blue water percolation (BWp). The values of WFP for irrigated (WFPI) and rainfed (WFPR) crops are 0.911 and 1.202 m3 kg-1, respectively. Irrigation plays an important role in food production, promoting the wheat yield by 170% and reducing the WFP by 24% compared to those of rainfed wheat production. Due to the low irrigation efficiency, more water is needed per kilogram in irrigated farmland in many arid regions, such as the Xinjiang, Ningxia and Gansu Provinces. We divided the 30 provinces of China into three categories according to the relationship between the TWUPI (TWU for per-unit product in irrigated farmland) and TWUPR (TWU

Initiation of Extension in South China Continental Margin during the Active-Passive Margin Transition: Thermochronological and Kinematic Constraints

NASA Astrophysics Data System (ADS)

Zuo, X.; Chan, L. S.

2015-12-01

The South China continental margin is characterized by a widespread magmatic belt, prominent NE-striking faults and numerous rifted basins filled by Cretaceous-Eocene sediments. The geology denotes a transition from active to passive margin, which led to rapid modifications of crustal stress configuration and reactivation of older faults in this area. Our zircon fission-track data in this region show two episodes of exhumation: The first episode, occurring during 170-120Ma, affected local parts of the Nanling Range. The second episode, a more regional exhumation event, occurred during 115-70Ma, including the Yunkai Terrane and the Nanling Range. Numerical geodynamic modeling was conducted to simulate the subduction between the paleo-Pacific plate and the South China Block. The modeling results could explain the fact that exhumation of the granite-dominant Nanling Range occurred earlier than that of the gneiss-dominant Yunkai Terrane. In addition to the difference in rock types, the heat from Jurassic-Early Cretaceous magmatism in Nanling may have softened the upper crust, causing the area to exhume more readily than Yunkai. Numerical modeling results also indicate that (1) high lithospheric geothermal gradient, high slab dip angle and low convergence velocity favor the reversal of crustal stress state from compression to extension in the upper continental plate; (2) late Mesozoic magmatism in South China was probably caused by a slab roll-back; and (3) crustal extension could have occurred prior to the cessation of plate subduction. The inversion of stress regime in the continental crust from compression to crustal extension imply that the Late Cretaceous-early Paleogene red-bed basins in South China could have formed during the late stage of the subduction, accounting for the occurrence of volcanic events in some sedimentary basins. We propose that the rifting started as early as Late Cretaceous, probably before the cessation of subduction process.

A Sea-Surface Radiation Data Set for Climate Applications in the Tropical Western Pacific and South China Sea

NASA Technical Reports Server (NTRS)

Chou, Ming-Dah; Chan, Pui-King; Yan, Michael M.-H.

2000-01-01

The sea-surface shortwave and longwave radiative fluxes have been retrieved from the radiances measured by Japan's Geostationary Meteorological Satellite 5. The surface radiation data set covers the domain 40S-40N and 90E-170W. The temporal resolution is 1 day, and the spatial resolution is 0.5 deg x 0.5 deg latitude-longitude. The retrieved surface radiation have been validated with the radiometric measurements at the Atmospheric Radiation Measuring (ARM) site on Manus island in the equatorial western Pacific for a period of 15 months. It has also been validated with the measurements at the radiation site on Dungsha island in the South China Sea during the South China Sea Monsoon Experiment (SCSMEX) Intensive Observing Period (May and June 1998). The data set is used to study the effect of El Nino and East Asian Summer monsoon on the heating of the ocean in the tropical western Pacific and the South China Sea. Interannual variations of clouds associated with El Nino and the East Asian Summer monsoon have a large impact on the radiative heating of the ocean. It has been found that the magnitude of the interannual variation of the seasonal mean surface radiative heating exceeds 40 W/sq m over large areas. Together with the Clouds and the Earth's Radiant Energy System (CERES) shortwave fluxes at top of the atmosphere and the radiative transfer calculations of clear-sky fluxes, this surface radiation data set is also used to study the impact of clouds on the solar heating of the atmosphere. It is found that clouds enhance the atmospheric solar heating by approx. 20 W/sq m in the tropical western Pacific and the South China Sea. This result is important for evaluating the accuracy of solar flux calculations in clear and cloudy atmospheres.

Vietnam’s South China Sea Territorial Disputes: A Path to Resolution

DTIC Science & Technology

2013-11-01

under Communist rule , but the South rejected the unification. From the mid-1960s until the mid-1970s the United States intervened in an unsuccessful...Southeast Asia’s long- term stability. China, Vietnam, and Taiwan all have claims based on history. Malaysia , Philippines, and Brunei have claims...the Spratly Islands presents an obstacle to dramatic improvements in regional relationships. The Philippines, Brunei, and Malaysia all claim

Poverty Eradication: Lessons from China and South Korea in the 1950s and 1960s.

ERIC Educational Resources Information Center

Wignaraja, Ponna

1996-01-01

Traces the search for economic development alternatives that go beyond conventional neo-classical and Marxist theory and practice. Outlines case studies of social and economic transformation in South Korea and China and delineates the differences between similar attempts in Latin America and Eastern Europe. (MJP)

Eastern Iowa, Northwestern Illinois

NASA Image and Video Library

1973-06-22

SL2-10-250 (May-June 1973) --- A vertical view of eastern Iowa and northwestern Illinois, as photographed from Skylab space station in Earth orbit. Davenport, Burlington and Muscatine, Iowa; and Rock Island and Moline, Illinois can be delineated on opposite sides of the Mississippi River. The Iowa River and tributaries of it can also be delineated. This photograph was taken with one of six lenses of the Itek-furnished Multispectral Photographic Facility Experiment S190-A mounted in the Multiple Docking Adapter (MDA) of the space station. A six-inch lens, using 70mm medium speed Ektachrome (SO-356) film, was used. Agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce and Interior; the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior's Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

Advances in the Study of the Structures and Bioactivities of Metabolites Isolated from Mangrove-Derived Fungi in the South China Sea

PubMed Central

Wang, Xin; Mao, Zhi-Gang; Song, Bing-Bing; Chen, Chun-Hua; Xiao, Wei-Wei; Hu, Bin; Wang, Ji-Wen; Jiang, Xiao-Bing; Zhu, Yong-Hong; Wang, Hai-Jun

2013-01-01

Many metabolites with novel structures and biological activities have been isolated from the mangrove fungi in the South China Sea, such as anthracenediones, xyloketals, sesquiterpenoids, chromones, lactones, coumarins and isocoumarin derivatives, xanthones, and peroxides. Some compounds have anticancer, antibacterial, antifungal and antiviral properties, but the biosynthesis of these compounds is still limited. This review summarizes the advances in the study of secondary metabolites from the mangrove-derived fungi in the South China Sea, and their biological activities reported between 2008 and mid-2013. PMID:24084782

Magnetic properties of the rivers feeding the South China Sea: a critical step for understanding the paleo-marine records.

NASA Astrophysics Data System (ADS)

Kissel, Catherine; Liu, Zhifei; Wandres, Camille; Liu, Qingsong

2014-05-01

In order to use the magnetic properties of marine sediments as a tracer for past changes in the precipitation rate and in oceanic water masses transport and exchanges, it is critical to identify and to characterize the different sources of the detrital fraction among which the magnetic particles. This is of peculiar importance in marginal seas such as the South China Sea extending from about 25°N to the equator. Thanks to the Westpac project, we had access to a number of sediments collected in the deltas of the main rivers feeding the South China Sea. This is represented on the Asian continent by the Pearl river, the Red River, the Mekong river, by Malaysia, Sumatra and Borneo regions with minor rivers but also contributing to the South China Sea, and finally by Luzon and Taiwan. The geological formations contributing to the river sediment discharges are different from one catchment basin to another as well as the present climatic conditions. The magnetic analyses conducted on the samples are the low-field magnetic susceptibility, the ARM acquisition and decay, the IRM acquisition and decay, the back-field acquisition, the thermal demagnetization of 3-axes IRM, the hysteresis parameters, the FORC diagrams. The obtained parameters all together allow us to define the nature of the magnetic grains and their grain size distribution when magnetite is dominant. Some degree of variability is observed at the river mouths, illustrating different geological sources at the local/regional scale. As an average, it appears that the Southern basin of the South China Sea is surrounded by regions richer in high coercivity magnetic minerals than the northern basin. This mineral is identified as hematite while magnetite is more abundant in the north. These results are complementary to the clay mineral assemblages previously determined on the same samples. We'll give some example of how this knowledge allows us to interpret the paleo-marine records from the South China Sea in terms

Internal Wave Study in the South China Sea Using SAR

NASA Technical Reports Server (NTRS)

Liu, Antony K.; Hsu, Ming-Kuang; Zukor, Dorothy (Technical Monitor)

2000-01-01

Recently, the internal wave distribution maps in the China Seas have been compiled from hundreds of ERS-1/2, RADARSAT, and Space Shuttle SAR (Synthetic Aperture Radar) images from 1993 to 1999. Based on internal wave distribution map, most of internal waves in the northeast part of South China Sea were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m due to strong current from the Kuroshio branching out into the South China Sea. Based on the observations from drilling rigs near DongSha Island by Amoco Production Co., the solitons may be generated in a 4 km wide channel between Batan and Sabtang islands in Luzon Strait. The proposed generation mechanism is similar to the lee wave formation from a shallow topography. Both depression and elevation internal waves have been observed in the same RADARSAT ScanSAR image on May 4, 1998 near DongSha Island. Furthermore, depression and elevation internal waves have also been observed by SAR at the same location on the shelf in April and June, 1993 (in different seasons) respectively. Numerical models have been used to interpret their generation mechanism and evolution processes. Based on the SAR images, near DongSha Island, the westward propagating huge internal solitons are often encountered and diffracted/broken by the coral reefs on the shelf. After passing the island, the diffracted waves will re-merge or interact with each other. It has been observed that after the nonlinear wave-wave interaction, the phase of wave packet is shifted and wavelength is also changed. Examples of mesoscale features observed in SAR images, such as fronts, raincells, bathymetry, ship wakes, and oil spills will be presented. Recent mooring measurements in April 1999 near Dongsha Island, future field test ASIAEX (Asian Seas International Acoustics Experiment) planned for April 2001, and some pretest survey data will be discussed in this paper.

Comparing the Experiences and Needs of Postsecondary International Students from China and South Korea

ERIC Educational Resources Information Center

Deters, Ping

2015-01-01

International students from China and South Korea are an increasingly important part of the international student body in many English-medium postsecondary institutions. The purpose of this qualitative study was to gain a deeper understanding of the experiences and needs of these two groups of students at a Canadian postsecondary institution. Data…

New marine data from Vietnam Margin limit the amount of extrusion of Indochina during the opening of the South China Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huchon, P.; Le Pichon, X.; Rangin, C.

1994-07-01

A total of 9300 km of high resolution, wide coverage multibeam (Simrad EM12) bathymetric data have been acquired offshore Vietnam during the Ponaga cruise of the R/V L'Atalante in May 1993. Gravity and magnetic measurements, 6-channel seismic data, as well as 6 dredges also have been obtained. East of central Vietnam, the margin displays northeast-southwest tectonic structures typical of a passive margin. The depth of the basement of the Nha Trang basin suggests that it could be of oceanic nature, with a 20 to 30 Ma age compatible with the age of the South China Sea oceanic crust located furthermore » east. Southeast of South Vietnam, the authors identified the western tip of the fossil axis of the South China Sea. It constitutes a propagating ridge into a highly stretched continental crust, partly intruded by volcanics. East of 110[degrees]30[prime]E, tilted blocks are symmetric with respect to the oceanic axis, whereas west of 110[degrees]30[prime]E they are mostly tilted toward the south, which suggests the occurrence a large listric normal fault associated with a large amount of extension. The normal faults bend progressively to a more northerly direction when approaching the north-south scarp that bounds the Conson basin. This geometry is compatible with a right-lateral motion, and the normal faults associated with the oceanic propagator suggest that the dextral motion is synchronous with at least the last phase of spreading in the South China Sea (23-16 Ma). Since recent offshore oil data have established that the prolongation of the Red River fault within the Gulf of Tonkin was affected by left-lateral motion from the Oligocene to the upper Miocene, the results suggest that the change from left-lateral motion in the Gulf of Tonkin to right-lateral motion along the Vietnam margin occurs because the South China Sea basin opens more rapidly than the extrusion of Indochina. Thus, the total amount of extrusion of Indochina probably does not exceed 100 or 200 km.« less

Sediment compaction and pore pressure prediction in deepwater basin of the South China Sea: Estimation from ODP and IODP drilling well data

NASA Astrophysics Data System (ADS)

Xie, Yangbing; Wu, Tuoyu; Sun, Jin; Zhang, Hanyu; Wang, Jiliang; Gao, Jinwei; Chen, Chuanxu

2018-02-01

Overpressure in deepwater basins not only causes serious soft sediment deformation, but also significantly affects the safety of drilling operations. Therefore, prediction of overpressure in sediments has become an important task in deepwater oil exploration and development. In this study, we analyze the drilling data from ODP Leg 184 Sites 1144, 1146, and 1148, and IODP Leg 349 Sites U1431, U1432, U1433, and U1435 to study the sediment compaction and controls in the northern South China Sea. Sedimentation rate, sediment content, distribution area, and buried depth are the factors that influence sediment compaction in the deepwater basin of the South China Sea. Among these factors, the sediment content is the most important. The fitted normal compacted coefficients and mudline porosity for an interval of 50 m shows disciplinary variation versus depth. The pore pressure predicted from different fitted results shows varying overpressure situations. The normal compaction trend from Site 1144 reflects the porosity variation trend in stable deposition basins in the northern South China Sea. The predicted pore pressure shows overpressure at Site 1144, which is attributed to compaction disequilibrium. Nevertheless, the mixed lithology column may influence the predicted over-pressure at Site 1148, which is responsible for the confusing result. Above all, we find that sediment compaction should serve as a proxy for pore pressure in the deepwater basin of the South China Sea.

Formation of early-middle Miocene red beds in the South China Sea: element geochemistry and mineralogy analysis

NASA Astrophysics Data System (ADS)

Lyu, X.; Liu, Z.

2017-12-01

The formation of oceanic red beds that usually present oxic and oligotrophic conditions with low sedimentation rate has been used to trace depositional paleoenvironment and paleoclimate change. Red beds overlying oceanic basalts were drilled at two adjacent Sites U1433 and U1434 of IODP Expedition 349 in the Southwest Subbasin of the South China Sea. The occurrence of early-middle Miocene red beds may indicate that at that time there was oxic and quiet marine environment in the deep South China Sea. To understand their formation of red-color, local depositional condition, and potential paleoceanographic significance, major elements (XRF), trace and rare earth elements (ICP-MS), Fe chemical speciation (modified sequential iron extraction procedure), and Fe oxic minerals (CBD and DRS) were analyzed. Geochemical and mineralogical data reveal that hematite and goethite are responsible for the reddish color and red beds were deposited under highly oxic, oligotrophic conditions with a little later hydrothermal influence in the South China Sea. Our results indicate that: (1) after treatment using the CBD procedure, the red samples presented a change in color to greenish, showing the iron oxides being responsible for the sediment color; (2) enriched Mn, depleted U, S enrichment factors, and negative Ce anomaly show that the water mass was pre-oxidized before transported to the study location; (3) low primary productivity was inferred from the lower P, Ba enrichment factors in red beds compared to non-red beds; (4) the excess Mo influx at the bottom may come from the later hydrothermal input; (5) the diverse Ca enrichment factors and correlations between Fe and Al suggest different allogenic sources for red beds at our two sites. We conclude that the red beds at Sites U1433 and U1434 despite their diverse sources both developed in externally oxidized water mass and low primary productivity conditions, and partially altered by hydrothermal fluids after their pelagic

Occurrence of Quaternary turbidite deposits in the central South China Sea: Response to global sea-level changes

NASA Astrophysics Data System (ADS)

Liu, Z.; Zhang, X.; Christophe, C.; Peleo-Alampay, A.; Guballa, J. D. S.; Li, P.; Liu, C.

2016-12-01

Terrigenous turbidite layers frequently occur at the upper 150-m-thick sedimentary sequence of Hole U1431D (15º22.54'N, 117 º00.00'E, 4240.5 m water depth), International Ocean Discovery Program (IODP) Expedition 349, near the relict spreading ridge in the central South China Sea. This study implies visual statistics combined with grain size, clay mineralogy, and Nd-Sr isotope analyses to reconstruct the occurrence of these turbidite layers. The age-model of combined calcareous nannofossils, planktonic foraminifers, and paleomagnetism suggests that the sedimentary sequence spans the entire Quaternary with an age of 2.6 Ma at the depth of 150 mcd below the seafloor. Our results show that the turbidite deposits are dominated by silt with sandy silt and silty clay, poorly sorted, and grading upward with erosion base. The occurrence of turbidite layers are highly frequent with about 3.06 layers per meter and an average thickness of 14.64 cm per layer above 96 mcd ( 1.6 Ma), while the lower part turbudite layers are less frequently developed with 1.16 layers per meter and an average thickness of 5.67 cm. Provenance analysis indicates that Taiwan, about 900 km northward to the studied site, is the major source for these terrigenous sediments, implying the long run-out turbidity current activity over the very low-gradient deep-sea plain of the South China Sea. The frequency of the turbidite layer occurrence is well correlated to the Quaternary global sea-level change history, with the high frequency occurred during the lower sea-level stands. Our study suggests that the glacial-interglacial-scale sea-level change has controlled terrigenous sediment input from Taiwan and the northern shelf of the South China Sea during the Quaternary. The increase of turbidite layer frequency since 1.6 Ma in the central South China Sea could be triggered by the enlarged amplitude of sea-level change.

Investigation of Spatial and Temporal Trends in Water Quality in Daya Bay, South China Sea

PubMed Central

Wu, Mei-Lin; Wang, You-Shao; Dong, Jun-De; Sun, Cui-Ci; Wang, Yu-Tu; Sun, Fu-Lin; Cheng, Hao

2011-01-01

The objective is to identify the spatial and temporal variability of the hydrochemical quality of the water column in a subtropical coastal system, Daya Bay, China. Water samples were collected in four seasons at 12 monitoring sites. The Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on water quality in Daya Bay. In the spatial pattern, two groups have been identified, with the help of multidimensional scaling analysis and cluster analysis. Cluster I consisted of the sites S3, S8, S10 and S11 in the west and north coastal parts of Daya Bay. Cluster I is mainly related to anthropogenic activities such as fish-farming. Cluster II consisted of the rest of the stations in the center, east and south parts of Daya Bay. Cluster II is mainly related to seawater exchange from South China Sea. PMID:21776234

Characterization of bacterial diversity associated with deep sea ferromanganese nodules from the South China Sea.

PubMed

Zhang, De-Chao; Liu, Yan-Xia; Li, Xin-Zheng

2015-09-01

Deep sea ferromanganese (FeMn) nodules contain metallic mineral resources and have great economic potential. In this study, a combination of culture-dependent and culture-independent (16S rRNA genes clone library and pyrosequencing) methods was used to investigate the bacterial diversity in FeMn nodules from Jiaolong Seamount, the South China Sea. Eleven bacterial strains including some moderate thermophiles were isolated. The majority of strains belonged to the phylum Proteobacteria; one isolate belonged to the phylum Firmicutes. A total of 259 near full-length bacterial 16S rRNA gene sequences in a clone library and 67,079 valid reads obtained using pyrosequencing indicated that members of the Gammaproteobacteria dominated, with the most abundant bacterial genera being Pseudomonas and Alteromonas. Sequence analysis indicated the presence of many organisms whose closest relatives are known manganese oxidizers, iron reducers, hydrogen-oxidizing bacteria and methylotrophs. This is the first reported investigation of bacterial diversity associated with deep sea FeMn nodules from the South China Sea.

Spatiotemporal patterns of drought at various time scales in Shandong Province of Eastern China

NASA Astrophysics Data System (ADS)

Zuo, Depeng; Cai, Siyang; Xu, Zongxue; Li, Fulin; Sun, Wenchao; Yang, Xiaojing; Kan, Guangyuan; Liu, Pin

2018-01-01

The temporal variations and spatial patterns of drought in Shandong Province of Eastern China were investigated by calculating the standardized precipitation evapotranspiration index (SPEI) at 1-, 3-, 6-, 12-, and 24-month time scales. Monthly precipitation and air temperature time series during the period 1960-2012 were collected at 23 meteorological stations uniformly distributed over the region. The non-parametric Mann-Kendall test was used to explore the temporal trends of precipitation, air temperature, and the SPEI drought index. S-mode principal component analysis (PCA) was applied to identify the spatial patterns of drought. The results showed that an insignificant decreasing trend in annual total precipitation was detected at most stations, a significant increase of annual average air temperature occurred at all the 23 stations, and a significant decreasing trend in the SPEI was mainly detected at the coastal stations for all the time scales. The frequency of occurrence of extreme and severe drought at different time scales generally increased with decades; higher frequency and larger affected area of extreme and severe droughts occurred as the time scale increased, especially for the northwest of Shandong Province and Jiaodong peninsular. The spatial pattern of drought for SPEI-1 contains three regions: eastern Jiaodong Peninsular and northwestern and southern Shandong. As the time scale increased to 3, 6, and 12 months, the order of the three regions was transformed into another as northwestern Shandong, eastern Jiaodong Peninsular, and southern Shandong. For SPEI-24, the location identified by REOF1 was slightly shifted from northwestern Shandong to western Shandong, and REOF2 and REOF3 identified another two weak patterns in the south edge and north edge of Jiaodong Peninsular, respectively. The potential causes of drought and the impact of drought on agriculture in the study area have also been discussed. The temporal variations and spatial patterns

Cenozoic exhumation history of South China: A case study from the Xuefeng Mt. Range

NASA Astrophysics Data System (ADS)

Wang, Yannan; Zhang, Jin; Zhang, Beihang; Zhao, Heng

2018-01-01

New apatite fission track (AFT) dating was applied to the Xuefeng Mt. Range and Yuanma Basin to constrain the Cenozoic exhumation process of the southeastern Yangtze Block, South China. The analyzed samples in this study have AFT ages ranging from 27.9 ± 2.5 to 61.5 ± 5.9 Ma, which are younger than the deposition or crystallization ages of the host rocks. The AFT analysis and thermal history modeling indicate that both the Xuefeng Mt. Range and the Yuanma Basin underwent significant exhumation during the early Cenozoic (ca. 60-40 Ma). These samples were rapidly exhumed to near the surface during this period. Our results suggest that an important tectonic event occurred along or near regional fault zones (e.g., the Qinhang Fault) in South China during the early Cenozoic (ca. 60-40 Ma). However, it is difficult to relate this event to the Eastern Sichuan fold belt, which is much older and is characterized by large-scale folding and thrusting. Combined with fieldwork in the Yuanma, Xupu, and Xinning basins, we refute the Cretaceous "Pan-Yangtze Basin" that was proposed to have been separated by the uplifted Xuefeng Mt. Range after the Late Cretaceous. The exhumation stage from ca. 60 Ma to 40 Ma was an important period during which plate movements across the eastern Asian and Pacific regions were reorganized. The early Cenozoic tectonothermal event in South China can be attributed to a change in the direction and speed of the subduction of the Pacific Plate beneath the Eurasian Plate. An Oligocene-Miocene cooling event was also recorded in the eastern Xuefeng Mt. Range, which we tentatively attribute to the activity of dextral faults in this area as a far-field effect of the collision between the Indian and Eurasian plates.

Study of crustal structure and stretch mechanism of central continental shelf of northern South China Sea

NASA Astrophysics Data System (ADS)

Cao, J.; Xia, S.; Sun, J.; Wan, K.; Xu, H.

2017-12-01

Known as a significant region to study tectonic relationship between South China block and South China Sea (SCS) block and the evolution of rifted basin in continental margin, the continental shelf of northern SCS documents the evolution from continental splitting to seafloor spreading of SCS. To investigate crustal structure of central continental shelf in northern SCS, two wide-angle onshore-offshore seismic experiments and coincident multi-channel seismic (MCS) profiles were carried out across the onshore-offshore transitional zone in northern SCS, 2010 and 2012. A total of 34 stations consisted of ocean bottom seismometers, portable and permanent land stations were deployed during the survey. The two-dimensional precise crustal structure models of central continental shelf in northern SCS was constructed from onshore to offshore, and the stretching factors along the P-wave velocity models were calculated. The models reveal that South China block is a typical continental crust with a 30-32 km Moho depth, and a localized high-velocity anomaly in middle-lower crust under land area near Hong Kong was imaged, which may reflect magma underplating caused by subduction of paleo-Pacific plate in late Mesozoic. The littoral fault zone is composed of several parallel, high-angle, normal faults that mainly trend northeast to northeast-to-east and dip to the southeast with a large displacement, and the fault is divided into several segments separated by the northwest-trending faults. The shelf zone south of LFZ was consisted of a differential thinning upper and lower continental crust, which indicate stretch thinning of passive continent margin during the Cenozoic spreading of the SCS. The results appear to further confirm that the northern margin of SCS experienced a transition from active margin to passive one during late Mesozoic and Cenozoic.

Changes of tropical cyclone landfalls in South China throughout the twenty-first century

NASA Astrophysics Data System (ADS)

Lok, Charlie C. F.; Chan, Johnny C. L.

2017-12-01

The nested regional climate/mesoscale modelling system developed by the authors is applied to the Hadley Centre Global Environment Model version 2-Earth System global model outputs to project future changes of landfalling tropical cyclone (TC) activity in the South China region. Results show that the modelling system is capable of reproducing the current TC landfall climatology, although it exhibits a noticeable southward bias of TC activity of in the western North Pacific. Future projections show a continuous northward migration of TC activity in the western North Pacific throughout the twenty-first century. Fewer TCs making landfall in South China are projected in the late century, but these landfalling TCs tend to be more intense. Investigations in the large-scale environment suggest that despite warmer sea surface temperature and weaker vertical wind shear, the drier and less cyclonic lower atmosphere all-season is responsible for the reduced TC activity. However, once a TC is formed, the environment it stays in is as wet as today and so it can intensify further than the present-day TCs. Inter-annual variability is also explored, and the influence of the ENSO variation appears to be smaller.

Long-term Trends and Variability of Eddy Activities in the South China Sea

NASA Astrophysics Data System (ADS)

Zhang, M.; von Storch, H.

2017-12-01

For constructing empirical downscaling models and projecting possible future states of eddy activities in the South China Sea (SCS), long-term statistical characteristics of the SCS eddy are needed. We use a daily global eddy-resolving model product named STORM covering the period of 1950-2010. This simulation has employed the MPI-OM model with a mean horizontal resolution of 10km and been driven by the NCEP reanalysis-1 data set. An eddy detection and tracking algorithm operating on the gridded sea surface height anomaly (SSHA) fields was developed. A set of parameters for the criteria in the SCS are determined through sensitivity tests. Our method detected more than 6000 eddy tracks in the South China Sea. For all of them, eddy diameters, track length, eddy intensity, eddy lifetime and eddy frequency were determined. The long-term trends and variability of those properties also has been derived. Most of the eddies propagate westward. Nearly 100 eddies travel longer than 1000km, and over 800 eddies have a lifespan of more than 2 months. Furthermore, for building the statistical empirical model, the relationship between the SCS eddy statistics and the large-scale atmospheric and oceanic phenomena has been investigated.

Recent 121-year variability of western boundary upwelling in the northern South China Sea

NASA Astrophysics Data System (ADS)

Liu, Yi; Peng, Zicheng; Shen, Chuan-Chou; Zhou, Renjun; Song, Shaohua; Shi, Zhengguo; Chen, Tegu; Wei, Gangjian; Delong, Kristine L.

2013-06-01

upwelling is typically related to the eastern boundary upwelling system, whereas the powerful southwest Asian summer monsoon can also generate significant cold, nutrient-rich deep water in western coastal zones. Here we present a sea surface temperature record (A.D. 1876-1996) derived from coral Porites Sr/Ca for an upwelling zone in the northern South China Sea. The upwelling-induced sea surface temperature anomaly record reveals prominent multidecadal variability driven by Asian summer monsoon dynamics with an abrupt transition from warmer to colder conditions in 1930, and a return to warmer conditions after 1960. Previous studies suggest the expected increase in atmospheric CO2 for the coming decades may result in intensification in the eastern boundary upwelling system, which could enhance upwelling of CO2-rich deep water thus exacerbating the impact of acidification in these productive zones. In contrast, the weakening trend since 1961 in the upwelling time series from the northern South China Sea suggests moderate regional ocean acidification from upwelling thus a stress relief for marine life in this region.

Dietary shift after 3600 cal yr BP and its influencing factors in northwestern China: Evidence from stable isotopes

NASA Astrophysics Data System (ADS)

Ma, Minmin; Dong, Guanghui; Jia, Xin; Wang, Hui; Cui, Yifu; Chen, Fahu

2016-08-01

Human diets rely on natural resource availability and can reflect social and cultural values. When environments, societies, and cultures change, diets may also shift. This study traced the extent of dietary change and the factors influencing such change. Through stable carbon and nitrogen isotopic analysis of late Neolithic and early Bronze Age human and animal bone collagen, we found that significant shifts in human diets were closely associated with intercontinental cultural exchanges in Eurasia and climate change in northwestern China. The isotopic evidence indicated that human diets mainly consisted of C4 foodstuffs (presumably millet and/or animals fed with C4 foods) around 4000 calibrated years before the present (cal yr BP), corresponding to the flourishing of millet agriculture in the context of the optimal climate conditions of the mid-Holocene. Subsequently, more C3 foods (probably wheat, barley, and animals fed with C3 foods) were added to human diets post-3600 cal yr BP when the climate became cooler and drier. Such dietary variation is also consistent with the increasing intensity of long-distance exchange after 4000 cal yr BP. While many factors can lead to human dietary shifts (e.g. climate change, population growth, cultural factors, and human migration), climate may have been a key factor in Gansu and Qinghai.

Dietary shift after 3600 cal yr BP and its influencing factors in northwestern China: Evidence from stable isotopes

NASA Astrophysics Data System (ADS)

Ma, Minmin; Dong, Guanghui; Jia, Xin; Wang, Hui; Cui, Yifu; Chen, Fahu

2017-04-01

:Human diets rely on natural resource availability and can reflect social and cultural values. When environments, societies, and cultures change, diets may also shift. This study traced the extent of dietary change and the factors influencing such change. Through stable carbon and nitrogen isotopic analysis of late Neolithic and early Bronze Age human and animal bone collagen, we found that significant shifts in human diets were closely associated with intercontinental cultural exchanges in Eurasia and climate change in northwestern China. The isotopic evidence indicated that human diets mainly consisted of C4 foodstuffs (presumably millet and/or animals fed with C4 foods) around 4000 calibrated years before the present (cal yr BP), corresponding to the flourishing of millet agriculture in the context of the optimal climate conditions of the mid-Holocene. Subsequently, more C3 foods (probably wheat, barley, and animals fed with C3 foods) were added to human diets post-3600 cal yr BP when the climate became cooler and drier. Such dietary variation is also consistent with the increasing intensity of long-distance exchange after 4000 cal yr BP. While many factors can lead to human dietary shifts (e.g. climate change, population growth, cultural factors, and human migration), climate may have been a key factor in Gansu and Qinghai.

Evidence for a fall raptor migration pathway across the South China Sea

USGS Publications Warehouse

Ellis, D.H.; Kepler, A.K.; Kepler, C.B.

1990-01-01

While conducting seabird surveys along the cruise track of the Soviet oceanographic Research Vessel Akademlk Korolev in the South China Sea in late October, 1988, we encountered about 150 land birds, including about 40 raptors. Most of the raptors were small accipiters, but we also recorded small numbers of Peregrine Falcons (Falco peregrinus) and Oriental Scops Owls (Otus sunia). We saw most of the raptors during a 3-day period in a restricted area ca 350 km southeast of the southern tip of the Indo-China Peninsula. The observations suggest that a significant raptor migration corridor exists between Viet Nam and Borneo. The behavior and body condition of the diurnal raptors suggest that they were in good health and were making extensive use of the ship for perching, roosting, and hunting.

Prevalence and influence factors of suicidal ideation among females and males in Northwestern urban China: a population-based epidemiological study.

PubMed

Xu, Huiwen; Zhang, Weijun; Wang, Xiaohua; Yuan, Jiaqi; Tang, Xinfeng; Yin, Yi; Zhang, Shengfa; Zhou, Huixuan; Qu, Zhiyong; Tian, Donghua

2015-09-25

Suicide is an urgent public health challenge for China. This study aims to examine the prevalence, influence factors, and gender differences of suicidal ideation among general population in Northwestern Urban China. Data used in this study were derived from the third wave of a cohort study of a randomized community sample with 4291 participants (≥ 20 years) in 2008 in Lanzhou City and Baiyin City, Gansu Province. Data were collected via face-to-face interview by the trained interviewers. Descriptive analyses, chi-square tests and multivariate logistic regressions were performed by using Stata 12.0, as needed. The prevalence of 12-month suicidal ideation was 4.29%, there was no significant difference between males and females [5.04% vs 3.62%, Adjusted Odds Ratio (AOR) = 0.83, p = 0.351]. Several risk factors for suicidal ideation were confirmed, including being unmarried (AOR = 1.55, p = 0.030), having depression symptoms (AOR = 2.33, p < 0.001), having other insurance (AOR = 1.83, p = 0.01) or no insurance (AOR = 1.73, p = 0.024). In addition, several influence factors were significantly different in males and females, such as being currently married (unmarried vs married, AOR = 1.84, p = 0.027, for females; no difference for males), feeling hopeless (hopless vs hopeful, AOR = 1.92, p = 0.06, for females; no difference for males), having other insurances (having other insurances vs having basic employee medical insurance, AOR = 1.92, p = 0.044, for males; no difference for females), having debts (having debts vs no debts, AOR = 2.69, p = 0.001, for males; no difference for females), currently smoking (smoking vs nonsmoking, AOR = 3.01, p = 0.019 for females, no difference for males), and currently drinking (drinking vs nondrinking, AOR =2.01, p = 0.022, for males; no difference for females). These findings suggested that comprehensive suicide prevention strategies should be developed or strengthened in order to prevent suicide ideation in

Restoration of mangrove plantations and colonisation by native species in Leizhou bay, South China

Treesearch

Hai Ren; Shuguang Jian; Hongfang Lu; Qianmei Zhang; Weijun Shen; Weidong Han; Zuoyun Yin; Qinfeng Guo

2008-01-01

To examine the natural colonisation of native mangrove species into remediated exotic mangrove stands in Leizhou Bay, South China, we compared soil physical–chemical properties, community structure and recruitments of barren mangrove areas, native mangrove species plantations, and exotic mangrove species—Sonneratia apetala Buch.Ham—between plantations and natural...

Pn tomography of South China Sea, Taiwan Island, Philippine archipelago, and adjacent regions

NASA Astrophysics Data System (ADS)

Li, Xibing; Song, Xiaodong; Li, Jiangtao

2017-02-01

The South China Sea (SCS) and its surrounding areas are geologically highly heterogeneous from the interactions of multiple plates in Southeast Asia (Eurasian plate, Indian-Australian plate, Philippine Sea plate, and Pacific plate). To understand the tectonics at depth, here we combined bulletin and handpicked data to conduct Pn tomography of the region. The results show distinct features that are correlated with the complex geology at surface, suggesting a lithosphere-scale tectonics of the region. Low Pn velocities are found along a belt of the western Pacific transpressional system from the Okinawa Trough and eastern East China Sea, across central and eastern Taiwan orogeny, to the island arcs of the Luzon Strait and the entire Philippine Islands, as well as under the Palawan Island and part of the continental margin north of the Pearl River Basin. High velocities are found under Ryukyu subduction zone, part of the Philippine subduction zone, part of the Eurasian subduction beneath the southwestern Taiwan, and the continent-ocean boundary between the south China and the SCS basin. The Taiwan Strait, the Mainland SE coast, and the main SCS basin sea are relatively uniform with average Pn values. Crustal thicknesses show large variations in the study region but also coherency with tectonic elements. The Pn pattern in Taiwan shows linear trends of surface geology and suggests strongly lithosphere-scale deformation of the young Taiwan orogenic belt marked by the deformation boundary under the Western Foothill and the Western Coastal Plain at depth, and the crustal thickness shows a complex pattern from the transpressional collision. Our observations are consistent with rifting and extension in the northern margin of the SCS but are not consistent with mantle upwelling as a mechanism for the opening and the subsequent closing of the SCS. The Philippine island arc is affected by volcanisms from both the Asian and Philippine Sea subductions in the south but mainly from

Canopy storage capacity of xerophytic shrubs in Northwestern China

NASA Astrophysics Data System (ADS)

Wang, Xin-ping; Zhang, Ya-feng; Hu, Rui; Pan, Yan-xia; Berndtsson, Ronny

2012-08-01

SummaryThe capacity of shrub canopy water storage is a key factor in controlling the rainfall interception. Thus, it affects a variety of hydrological processes in water-limited arid desert ecosystems. Vast areas of revegetated desert ecosystems in Northwestern China are occupied by shrub and dwarf shrub communities. Yet, data are still scarce regarding their rainwater storage capacity. In this study, simulated rainfall tests were conducted in controlled conditions for three dominant xerophytic shrub types in the arid Tengger Desert. Eight rainfall intensities varying from 1.15 to 11.53 mm h-1 were used to determine the canopy water storage capacity. The simulated rainfall intensities were selected according to the long-term rainfall records in the study area. The results indicate that canopy storage capacity (expressed in water storage per leaf area, canopy projection area, biomass, and volume of shrub respectively) increased exponentially with increase in rainfall intensity for the selected shrubs. Linear relationships were found between canopy storage capacity and leaf area (LA) or leaf area index (LAI), although there was a striking difference in correlation between storage capacity and LA or LAI of Artemisia ordosica compared to Caragana korshinskii and Hedysarum scoparium. This is a result of differences in biometric characteristics, especially canopy morphology between the shrub species. Pearson correlation coefficient indicated that LA and dry biomass are better predictors as compared to canopy projection area and volume of samples for precise estimation of canopy water storage capacity. In terms of unit leaf area, mean storage capacity was 0.39 mm (range of 0.24-0.53 mm), 0.43 mm (range of 0.28-0.60 mm), and 0.61 mm (range of 0.29-0.89 mm) for C. korshinskii, H. scoparium, and A. ordosica, respectively. Correspondingly, divided per unit dry biomass, mean storage capacity was 0.51 g g-1 (range of 0.30-0.70 g g-1), 0.41 g g-1 (range of 0.26-0.57 g g-1), and

Skillful seasonal predictions of winter precipitation over southern China

NASA Astrophysics Data System (ADS)

Lu, Bo; Scaife, Adam A.; Dunstone, Nick; Smith, Doug; Ren, Hong-Li; Liu, Ying; Eade, Rosie

2017-07-01

Southern China experiences large year-to-year variability in the amount of winter precipitation, which can result in severe social and economic impacts. In this study, we demonstrate prediction skill of southern China winter precipitation by three operational seasonal prediction models: the operational Global seasonal forecasting system version 5 (GloSea5), the NCEP Climate Forecast System (CFSv2) and the Beijing Climate Center Climate System Model (BCC-CSM1.1m). The correlation scores reach 0.76 and 0.67 in GloSea5 and CFSv2, respectively; and the amplitude of the ensemble mean forecast signal is comparable to the observed variations. The skilful predictions in GloSea5 and CFSv2 mainly benefit from the successful representation of the observed ENSO teleconnection. El Niño weakens the Walker circulation and leads to the strengthening of the subtropical high over the northwestern Pacific. The anti-cyclone then induces anomalous northward flow over the South China Sea and brings water vapor to southern China, resulting in more precipitation. This teleconnection pattern is too weak in BCC-CSM1.1m, which explains its low skill (0.13). Whereas the most skilful forecast system is also able to simulate the influence of the Indian Ocean on southern China precipitation via changes in southwesterly winds over the Bay of Bengal. Finally, we examine the real-time forecast for 2015/16 winter when a strong El Niño event led to the highest rainfall over southern China in recent decades. We find that the GloSea5 system gave good advice as it produced the third wettest southern China in the hindcast, but underestimated the observed amplitude. This is likely due to the underestimation of the Siberian High strength in 2015/2016 winter, which has driven strong convergence over southern China. We conclude that some current seasonal forecast systems can give useful warning of impending extremes. However, there is still need for further model improvement to fully represent the complex

Prelude of benthic community collapse during the end-Permian mass extinction in siliciclastic offshore sub-basin: Brachiopod evidence from South China

NASA Astrophysics Data System (ADS)

Wu, Huiting; He, Weihong; Weldon, Elizabeth A.

2018-04-01

Analysis of the Permian-Triassic palaeocommunities from basinal facies in South China provides an insight into the environmental deterioration occurring in the prelude to the mass extinction event. Quantitative and multivariate analyses on three brachiopod palaeocommunities from the Changhsingian to the earliest Triassic in basinal facies in South China have been undertaken in this study. Although the end-Permian extinction has been proved to be a one-stepped event, ecological warning signals appeared in the palaeocommunities long before the main pulse of the event. A brachiopod palaeocommunity turnover occurred in the upper part of the Clarkina changxingensis Zone, associated with a significant decrease of palaeocommunity diversity and brachiopod body size. During this turnover the dominant genera changed from Fusichonetes and Crurithyris (or/and Paracrurithyris) to the more competitive genus Crurithyris (or/and Paracrurithyris). The brachiopod palaeocommunity turnover was supposed to be triggered by the decreased marine primary productivity and increased volcanic activity. Moreover, such early warning signals are found not only in the deep-water siliceous facies, but also in the shallow-water clastic facies and carbonate rock facies in South China.

Changing character of rainfall in eastern China, 1951-2007.

PubMed

Day, Jesse A; Fung, Inez; Liu, Weihan

2018-02-27

The topography and continental configuration of East Asia favor the year-round existence of storm tracks that extend thousands of kilometers from China into the northwestern Pacific Ocean, producing zonally elongated patterns of rainfall that we call "frontal rain events." In spring and early summer (known as "Meiyu Season"), frontal rainfall intensifies and shifts northward during a series of stages collectively known as the East Asian summer monsoon. Using a technique called the Frontal Rain Event Detection Algorithm, we create a daily catalog of all frontal rain events in east China during 1951-2007, quantify their attributes, and classify all rainfall on each day as either frontal, resulting from large-scale convergence, or nonfrontal, produced by local buoyancy, topography, or typhoons. Our climatology shows that the East Asian summer monsoon consists of a series of coupled changes in frontal rain event frequency, latitude, and daily accumulation. Furthermore, decadal changes in the amount and distribution of rainfall in east China are overwhelmingly due to changes in frontal rainfall. We attribute the "South Flood-North Drought" pattern observed beginning in the 1980s to changes in the frequency of frontal rain events, while the years 1994-2007 witnessed an uptick in event daily accumulation relative to the rest of the study years. This particular signature may reflect the relative impacts of global warming, aerosol loading, and natural variability on regional rainfall, potentially via shifting the East Asian jet stream.

Urinary metabolites of organophosphate esters in children in South China: Concentrations, profiles and estimated daily intake.

PubMed

Chen, Yi; Fang, Jianzhang; Ren, Lu; Fan, Ruifang; Zhang, Jianqing; Liu, Guihua; Zhou, Li; Chen, Dingyan; Yu, Yingxin; Lu, Shaoyou

2018-04-01

Organophosphate esters (OPEs) are widely used in household products as flame retardants or plasticizers and have become ubiquitous pollutants in environmental media. However, little is known about OPE metabolites in humans, especially in children. In this study, eight OPE metabolites were measured in 411 urine samples collected from 6 to 14-year-old children in South China. Bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCIPP) and diphenyl phosphate (DPHP) were the dominant OPE metabolites, and their median concentrations were 1.04, 0.15 and 0.28 μg/L, respectively. The levels of urinary OPE metabolites in the present study were much lower than those in participants from other countries, with the exception of BCEP, suggesting widespread exposure to tris(2-chlorethyl) phosphate (TCEP, the parent chemical of BCEP) in South China. No significant difference in the concentrations of any of the OPE metabolites was observed between males and females (p > .05). Significant negative correlations were observed between age and BCEP, BCIPP, bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), di-o-cresyl phosphate (DoCP) and di-p-cresyl phosphate (DpCP) (DCP), or DPHP (p < .05). Pearson correlation coefficients between urinary OPE metabolites indicated multiple sources and OPE exposure pathways in children. The estimated daily intake suggested that children in South China have a relatively high exposure level to TCEP. To the best of our knowledge, this is the first study to report the urinary levels of OPE metabolites in Chinese children. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spectral Interpretation of Wave-vortex Duality in Northern South China Sea

NASA Astrophysics Data System (ADS)

Cao, H.; Jing, Z.; Yan, T.

2017-12-01

The mesoscale to submesocale oceanic dynamics are characterized by a joint effect of vortex and wave component, which primarily declares the partition between geostrophic balanced and unbalanced flows. The spectral method is a favorable approach that can afford the muti-scale analysis. This study investigates the characteristics of horizontal wavenumber spectra in Nothern South China Sea using orbital altimeter data (SARA/AltiKa), 13-yr shipboard ADCP (Acoustic Doppler Current Profiler) measurements (2014-2016), and a high-resolution numerical simulation (llc4320 Mitgcm). The observed SSH (sea surface height) spectrum presents a conspicuous transition at scales of 50-100 km, which clearly shows the inconsistency with geostrophic balance. The Helmholtz decomposition separating the wave and vortex energy for the spectra of ADCP and numerical model data shows that ageostrophic flows should be responsible for the spectral discrepancy with the QG (qusi-geostrophic) turbulence theory. Generally, it is found that inertia-gravity waves (including internal tides) govern the significant kinetic energy in the submesoscale range in Northern South China Sea. More specific analysis suggests that the wave kinetic energy can extend to a large scale of 500 km or more from the zonal velocity spectra at the left-center of Luzon Strait, which appears to be dominated by inertia-gravity waves likely emitted by the intrusion of the west pacific at Luzon Strait. Instead, the development of eddy kinetic energy at this place is strictly constrained by the width of the strait.

Three new aaptamine derivatives from the South China Sea sponge Aaptos aaptos.

PubMed

Gan, Jian-Hong; Hu, Wen-Zhen; Yu, Hao-Bing; Yang, Fan; Cao, Meng-Xue; Shi, Hua-Jin; Kang, Yong-Feng; Han, Bing-Nan

2015-01-01

Three new aaptamine derivatives (1-3), together with six known related compounds (4-9), have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated on the basis of spectroscopic analyses. Compounds 1, 4, 5, 7, and 9 showed cytotoxic activities against HeLa, K562, MCF-7, and U937 cell lines with IC50 values in the range of 0.90-12.32 μM.

Isotopic composition and distribution of plutonium in northern South China Sea sediments revealed continuous release and transport of Pu from the Marshall Islands.

PubMed

Wu, Junwen; Zheng, Jian; Dai, Minhan; Huh, Chih-An; Chen, Weifang; Tagami, Keiko; Uchida, Shigeo

2014-03-18

The (239+240)Pu activities and (240)Pu/(239)Pu atom ratios in sediments of the northern South China Sea and its adjacent Pearl River Estuary were determined to examine the spatial and temporal variations of Pu inputs. We clarified that Pu in the study area is sourced from a combination of global fallout and close-in fallout from the Pacific Proving Grounds in the Marshall Islands where above-ground nuclear weapons testing was carried out during the period of 1952-1958. The latter source dominated the Pu input in the 1950s, as evidenced by elevated (240)Pu/(239)Pu atom ratios (>0.30) in a dated sediment core. Even after the 1950s, the Pacific Proving Grounds was still a dominant Pu source due to continuous transport of remobilized Pu from the Marshall Islands, about 4500 km away, along the North Equatorial Current followed by the transport of the Kuroshio current and its extension into the South China Sea through the Luzon Strait. Using a simple two end-member mixing model, we have quantified the contributions of Pu from the Pacific Proving Grounds to the northern South China Sea shelf and the Pearl River Estuary are 68% ± 1% and 30% ± 5%, respectively. This study also confirmed that there were no clear signals of Pu from the Fukushima Daiichi Nuclear Power Plant accident impacting the South China Sea.

Culture-dependent and culture-independent diversity of Actinobacteria associated with the marine sponge Hymeniacidon perleve from the South China Sea.

PubMed

Sun, Wei; Dai, Shikun; Jiang, Shumei; Wang, Guanghua; Liu, Guohui; Wu, Houbo; Li, Xiang

2010-06-01

In this report, the diversity of Actinobacteria associated with the marine sponge Hymeniacidon perleve collected from a remote island of the South China Sea was investigated employing classical cultivation and characterization, 16S rDNA library construction, 16S rDNA-restriction fragment length polymorphism (rDNA-RFLP) and phylogenetic analysis. A total of 184 strains were isolated using seven different media and 24 isolates were selected according to their morphological characteristics for phylogenetic analysis on the basis of their 16S rRNA gene sequences. Results showed that the 24 isolates were assigned to six genera including Salinispora, Gordonia, Mycobacterium, Nocardia, Rhodococcus and Streptomyces. This is the first report that Salinispora is present in a marine sponge from the South China Sea. Subsequently, 26 rDNA clones were selected from 191 clones in an Actinobacteria-specific 16S rDNA library of the H. perleve sample, using the RFLP technique for sequencing and phylogenetic analysis. In total, 26 phylotypes were clustered in eight known genera of Actinobacteria including Mycobacterium, Amycolatopsis, Arthrobacter, Brevibacterium, Microlunatus, Nocardioides, Pseudonocardia and Streptomyces. This study contributes to our understanding of actinobacterial diversity in the marine sponge H. perleve from the South China Sea.

Magnetic minerals in three Asian rivers draining into the South China Sea: Pearl, Red, and Mekong Rivers

NASA Astrophysics Data System (ADS)

Kissel, Catherine; Liu, Zhifei; Li, Jinhua; Wandres, Camille

2016-05-01

The use of the marine sedimentary magnetic properties, as tracers for changes in precipitation rate and in oceanic water masses transport and exchanges, implies to identify and to characterize the different sources of the detrital fraction. This is of particular importance in closed and/or marginal seas such as the South China Sea. We report on the magnetic properties of sedimentary samples collected in three main Asian rivers draining into the South China Sea: the Pearl, Red, and Mekong Rivers. The geological formations as well as the present climatic conditions are different from one catchment to another. The entire set of performed magnetic analyses (low-field magnetic susceptibility, ARM acquisition and decay, IRM acquisition and decay, back-field acquisition, thermal demagnetization of three-axes IRM, hysteresis parameters, FORC diagrams, and low-temperature magnetic measurements) allow us to identify the magnetic mineralogy and the grain-size distribution when magnetite is dominant. Some degree of variability is observed in each basin, illustrating different parent rocks and degree of weathering. On average it appears that the Pearl River is rich in magnetite along the main stream while the Mekong River is rich in hematite. The Red River is a mixture of the two. Compared to clay mineral assemblages and major element contents previously determined on the same samples, these new findings indicate that the magnetic fraction brings complementary information of great interest for environmental reconstructions based on marine sediments from the South China Sea.

Alkaloids and Sesquiterpenes from the South China Sea Gorgonian Echinogorgia pseudossapo

PubMed Central

Gao, Cheng-Hai; Wang, Yi-Fei; Li, Shen; Qian, Pei-Yuan; Qi, Shu-Hua

2011-01-01

Five zoanthoxanthin alkaloids (1–5) and four sesquiterpenes (6–9) were isolated from the South China Sea gorgonian Echinogorgia pseudossapo. Their structures were determined on the bases of extensive spectroscopic analyses, including 1D and 2D NMR data. Among them, pseudozoanthoxanthins III and IV (1–2), 8-hydroxy-6β-methoxy-14- oxooplop-6,12-olide (6) and 3β-methoxyguaian-10(14)-en-2β-ol (7) were new, 1 and 3 showed mild anti-HSV-1 activity, and 7 showed significant antilarval activity towards Balanus amphitrite larvae. PMID:22163197

Trace Element Accumulation and Tissue Distribution in the Purpleback Flying Squid Sthenoteuthis oualaniensis from the Central and Southern South China Sea.

PubMed

Wu, Yan Yan; Shen, Yu; Huang, Hui; Yang, Xian Qing; Zhao, Yong Qiang; Cen, Jian Wei; Qi, Bo

2017-01-01

Sthenoteuthis oualaniensis is a species of cephalopod that is becoming economically important in the South China Sea. As, Cd, Cr, Cu, Hg, Pb, and Zn concentrations were determined in the mantle, arms, and digestive gland of S. oualaniensis from 31 oceanographic survey stations in the central and southern South China Sea. Intraspecific and interspecific comparisons with previous studies were made. Mean concentrations of trace elements analyzed in arms and mantle were in the following orders: Zn > Cu > Cd > Cr > As > Hg. In digestive gland, the concentrations of Cd and Cu exceed that of Zn. All the Pb concentrations were under the detected limit.

Soil seed banks in four 22-year-old plantations in South China: implications for restoration

Treesearch

Jun Wang; Hai Ren; Long Yang; Danyan Li; Qinfeng Guo

2009-01-01

To better understand the potentials of the soil seed banks in facilitating succession towards a morenatural forest of native tree species, we quantified the size and composition of the soil seed banks inestablished plantations in South China. The seed banks were from four typical 22-year-old plantations, i.e., legume, mixed-...

Origin of the Dongsha Event in the South China Sea

NASA Astrophysics Data System (ADS)

Xie, Zhiyuan; Sun, Longtao; Pang, Xiong; Zheng, Jinyun; Sun, Zhen

2017-12-01

Post-rift tectonic activities have been widely observed in the northern continental margin of the South China Sea, especially during the late Miocene. Large numbers of faults became active. Unconformities, uplift of faulted blocks, sequence tilting, erosion along the Dongsha massif and canyon incision were also discriminated at this stage in the Pearl River Mouth basin (PRMB) and the area to the east. This tectonism has been named Dongsha Event. A number of hypotheses have been put forward to explain the mechanism of the Dongsha Event, such as high-velocity lower crustal flow, magmatic underplating, and arc-continent collision. To investigate the tectonic dynamics, sequence contact relationships, fault activities, and magmatism were analyzed along large numbers of seismic profiles that cover the eastern PRMB and Southwest Taiwan Basin. The timing, affected regions, and differences in the intensity of tectonic deformation were assessed, upon which the plate bending model was favored. In order to check the reasonableness of plate bending model, effective elastic thickness and other geodynamic parameters were calculated constrained by uplift area width and regarding the trench as sediment filling. A maximum Te value of 27 km and a minimum value of 4 km were obtained. Integrating with the former stress field calculation, we conclude that the Dongsha Event was mainly affected by subduction and collision of the South China Sea toward the Philippine Sea plate. This event commenced at about 10 Ma and peaked at around 3.6 Ma. Although the high effective elastic thickness required is a problem to be addressed, this research provides by far the most comprehensive evidences to the mechanism of the Dongsha Event.

Temporal monitoring of vessels activity using day/night band in Suomi NPP on South China Sea

NASA Astrophysics Data System (ADS)

Yamaguchi, Takashi; Asanuma, Ichio; Park, Jong Geol; Mackin, Kenneth J.; Mittleman, John

2017-05-01

In this research, we focus on vessel detection using the satellite imagery of day/night band (DNB) on Suomi NPP in order to monitor the change of vessel activity on the region of South China Sea. In this paper, we consider the relation between the temporal change of vessel activities and the events on maritime environment based on the vessel traffic density estimation using DNB. DNB is a moderate resolution (350-700m) satellite imagery but can detect the fishing light of fishery boats in night time for every day. The advantage of DNB is the continuous monitoring on wide area compared to another vessel detection and locating system. However, DNB gave strong influence of cloud and lunar refection. Therefore, we additionally used Brightness Temperature at 3.7μm(BT3.7) for cloud information. In our previous research, we construct an empirical vessel detection model that based on the DNB contrast and the estimation of cloud condition using BT3.7. Moreover, we proposed a vessel traffic density estimation method based on empirical model. In this paper, we construct the time temporal density estimation map on South China Sea and East China Sea in order to extract the knowledge from vessel activities change.

SOUTH SIDE EXTERIOR OF SMOKESTACK, ALONG WITH POWER PLANT (BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

SOUTH SIDE EXTERIOR OF SMOKESTACK, ALONG WITH POWER PLANT (BUILDING 45) - National Home for Disabled Volunteer Soldiers, Northwestern Branch, Smoke Stack, 5000 West National Avenue, Milwaukee, Milwaukee County, WI

Levels and distribution of heavy metals in atmospheric particular matters over the northern South China Sea.

PubMed

Xu, Weihai; Yan, Wen; Zhang, Gan; Li, Jun; Miao, Li; Huang, Weixia

2014-01-01

Oceans play a significant role in the cycling of trace metals and persistent organic pollutants. In this study, aerosol samples covering the whole northern South China Sea (SCS) were collected in 2005 and 2007, respectively, for analysis of trace metals and major elements. The levels of trace metals detected ranged from 0.514 to 119 ng/m(3) in 2005 and from 0.130 to 24.2 ng/m(3) in 2007, respectively. Cu, Zn, and Pb were the three predominant metals with high enrichment factors (>10), indicating the strong anthropogenic inputs. The trace metals over SCS were comparable to the values in suburban and background sites of South China, but generally higher than those over other seas and oceans. Considering the fact that they were influenced by their proximity to source regions and air mass origins, the elevated metals in 2005 were probably attributed to the strong wind and long-range atmospheric transport driven by Asian monsoon.

Subduction of a low-salinity water mass around the Xisha Islands in the South China Sea.

PubMed

Huang, Zhida; Zhuang, Wei; Liu, Hailong; Hu, Jianyu

2018-02-15

Based on three climatologically observed temperature and salinity datasets (i.e., GDEM-V3, SCSPOD14 and WOA13), this paper reports a low-salinity (~34.32) water mass in the subsurface-to-intermediate layer around the Xisha Islands in the South China Sea. This water mass mainly subducts from the surface layer into the intermediate layer, characterized by a relatively low potential vorticity tongue extending from the bottom of mixed layer to the thermocline, and accompanied by a thermocline ventilation in spring (especially in April). The potential dynamics are the joint effects of negative wind stress curl, and an anticyclonic eddy triggered by the inherent topographic effect of the Xisha Islands, reflecting that downward vertical motion dominates the subduction. Despite lacking of the homogenous temperature and density, the low-salinity water mass is to some extent similar to the classic mode water and can be regarded as a deformed mode water in the South China Sea.

Assessment for water quality by artificial neural network in Daya Bay, South China Sea.

PubMed

Wu, Mei-Lin; Wang, You-Shao; Gu, Ji-Dong

2015-10-01

In this study, artificial neural network such as a self-organizing map (SOM) was used to assess for the effects caused by climate change and human activities on the water quality in Daya Bay, South China Sea. SOM has identified the anthropogenic effects and seasonal characters of water quality. SOM grouped the four seasons as four groups (winter, spring, summer and autumn). The Southeast Asian monsoons, northeasterly from October to the next April and southwesterly from May to September have also an important influence on the water quality in Daya Bay. Spatial pattern is mainly related to anthropogenic activities and hydrodynamics conditions. In spatial characteristics, the water quality in Daya Bay was divided into two groups by chemometrics. The monitoring stations (S3, S8, S10 and S11) were in these area (Dapeng Ao, Aotou Harbor) and northeast parts of Daya Bay, which are areas of human activity. The thermal pollution has been observed near water body in Daya Bay Nuclear Power Plant (S5). The rest of the monitoring sites were in the south, central and eastern parts of Daya Bay, which are areas that experience water exchanges from South China Sea. The results of this study may provide information on the spatial and temporal patterns in Daya Bay. Further research will be carry out more research concerning functional changes in the bay ecology with respect to changes in climatic factor, human activities and bay morphology in Daya Bay.

Climate warming, euxinia and carbon isotope perturbations during the Carnian (Triassic) Crisis in South China

NASA Astrophysics Data System (ADS)

Sun, Y. D.; Wignall, P. B.; Joachimski, M. M.; Bond, D. P. G.; Grasby, S. E.; Lai, X. L.; Wang, L. N.; Zhang, Z. T.; Sun, S.

2016-06-01

The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont apatite indicate a double-pulse warming event. The CHE coincided with an initial warming of 4 °C. This was followed by a transient cooling period and then a prolonged ∼7 °C warming in the later Carnian (Tuvalian 2). Carbon isotope perturbations associated with the CHE of western Tethys occurred contemporaneously in South China, and mark the start of a prolonged period of carbon cycle instability that persisted until the late Carnian. The dry-wet transition during the CHE coincides with the negative carbon isotope excursion and the temperature rise, pointing to an intensification of hydrologic cycle activities due to climatic warming. While carbonate platform shutdown in western Tethys is associated with an influx of siliciclastic sediment, the eastern Tethyan carbonate platforms are overlain by deep-water anoxic facies. The transition from oxygenated to euxinic facies was via a condensed, manganiferous carbonate (MnO content up to 15.1 wt%), that records an intense Mn shuttle operating in the basin. Significant siliciclastic influx in South China only occurred after the CHE climatic changes and was probably due to foreland basin development at the onset of the Indosinian Orogeny. The mid-Carnian biotic crisis thus coincided with several phenomena associated with major extinction events: a carbonate production crisis, climate warming, δ13 C oscillations, marine anoxia, biotic turnover and flood basalt eruptions (of the Wrangellia Large Igneous Province).

Temporal and Spatial Diversity of Bacterial Communities in Coastal Waters of the South China Sea

PubMed Central

Du, Jikun; Xiao, Kai; Li, Li; Ding, Xian; Liu, Helu; Lu, Yongjun; Zhou, Shining

2013-01-01

Bacteria are recognized as important drivers of biogeochemical processes in all aquatic ecosystems. Temporal and geographical patterns in ocean bacterial communities have been observed in many studies, but the temporal and spatial patterns in the bacterial communities from the South China Sea remained unexplored. To determine the spatiotemporal patterns, we generated 16S rRNA datasets for 15 samples collected from the five regularly distributed sites of the South China Sea in three seasons (spring, summer, winter). A total of 491 representative sequences were analyzed by MOTHUR, yielding 282 operational taxonomic units (OTUs) grouped at 97% stringency. Significant temporal variations of bacterial diversity were observed. Richness and diversity indices indicated that summer samples were the most diverse. The main bacterial group in spring and summer samples was Alphaproteobacteria, followed by Cyanobacteria and Gammaproteobacteria, whereas Cyanobacteria dominated the winter samples. Spatial patterns in the samples were observed that samples collected from the coastal (D151, D221) waters and offshore (D157, D1512, D224) waters clustered separately, the coastal samples harbored more diverse bacterial communities. However, the temporal pattern of the coastal site D151 was contrary to that of the coastal site D221. The LIBSHUFF statistics revealed noticeable differences among the spring, summer and winter libraries collected at five sites. The UPGMA tree showed there were temporal and spatial heterogeneity of bacterial community composition in coastal waters of the South China Sea. The water salinity (P=0.001) contributed significantly to the bacteria-environment relationship. Our results revealed that bacterial community structures were influenced by environmental factors and community-level changes in 16S-based diversity were better explained by spatial patterns than by temporal patterns. PMID:23785512

Geomagnetic paleointensity dating of South China Sea sediments for the last 130 kyr

NASA Astrophysics Data System (ADS)

Xiaoqiang, Yang; Heller, Friedrich; Nengyou, Wu; Jie, Yang; Zhihua, Su

2009-06-01

Relative paleointensity records from the northern South China Sea, northwest Pacific Ocean were studied in two gravity piston cores. Continuous mineral magnetic and paleomagnetic measurements were made using discrete sediment samples. Detailed rock magnetic parameters, such as thermomagnetic and high-field hysteresis data, indicate that pseudo-single domain magnetite in a narrow range of grain-size and concentration is the main contributor to the remanent magnetization. The uniform magnetic mineralogy meets the commonly accepted criteria for establishing relative paleointensity records. The relative paleointensity (RPI) curves were constructed by normalizing the natural remanent magnetization (NRM) with isothermal remanent magnetization (IRM), both in the 20-60 mT demagnetization state. Dating constraints have been provided by radiocarbon ages in the upper 400 cm of both cores. Furthermore, we have correlated our paleointensity records with NAPIS-75, S.Atlantic-1089, Sint-200 and NOPAPIS-250 to determine the chronological RPI framework for the South China Sea (SCS-PIS). Although some temporal offsets of paleointensity features between the different records have been recognized, their similar shape suggests that relative paleointensity on the 10 3-10 4 year scale is globally coherent and can provide an age framework for sediments independent of δ18O ages.

Spatial diversity of bacterioplankton communities in surface water of northern South China Sea.

PubMed

Li, Jialin; Li, Nan; Li, Fuchao; Zou, Tao; Yu, Shuxian; Wang, Yinchu; Qin, Song; Wang, Guangyi

2014-01-01

The South China Sea is one of the largest marginal seas, with relatively frequent passage of eddies and featuring distinct spatial variation in the western tropical Pacific Ocean. Here, we report a phylogenetic study of bacterial community structures in surface seawater of the northern South China Sea (nSCS). Samples collected from 31 sites across large environmental gradients were used to construct clone libraries and yielded 2,443 sequences grouped into 170 OTUs. Phylogenetic analysis revealed 23 bacterial classes with major components α-, β- and γ-Proteobacteria, as well as Cyanobacteria. At class and genus taxon levels, community structure of coastal waters was distinctively different from that of deep-sea waters and displayed a higher diversity index. Redundancy analyses revealed that bacterial community structures displayed a significant correlation with the water depth of individual sampling sites. Members of α-Proteobacteria were the principal component contributing to the differences of the clone libraries. Furthermore, the bacterial communities exhibited heterogeneity within zones of upwelling and anticyclonic eddies. Our results suggested that surface bacterial communities in nSCS had two-level patterns of spatial distribution structured by ecological types (coastal VS. oceanic zones) and mesoscale physical processes, and also provided evidence for bacterial phylogenetic phyla shaped by ecological preferences.

Preliminary bathymetry of Northwestern Fiord and Neoglacial changes of Northwestern Glacier

USGS Publications Warehouse

Post, Austin

1980-01-01

The first preliminary bathymetry (at 1:20,000 scale) and other scientific investigations of Northwestern Fiord, Alaska, were conducted by the Research Vessel Growler in 1978, disclosing this 10.5-mile-long branched waterway to be a deep basin enclosed by a terminal-moraine shoal. The basin was formerly filled by Northwestern Glacier, which began a drastic retreat around 1909 and reached the head of the main arm around 1960. Soundings and profiles show the main channel to be as much as 970 feet deep and to have the typical U shape of a severely glacially eroded valley; since the glacier 's retreat, sediments have formed nearly level deposits in the deepest reaches, while the rest of the basin has a hard, rocky bottom. Preneoglacial forest debris dated by carbon-14 indicates Northwestern Glacier to have advanced into the fiord prior to 1,385 years before present (B.P.); a branch glacier evidently advanced into forest 1,635 years B.P. The combined glaciers from several arms culminated on the present terminal-moraine shoal around 1894. (USGS)

Bioremediation and fodder potentials of two Sargassum spp. in coastal waters of Shenzhen, South China.

PubMed

Yu, Zonghe; Zhu, Xiaoshan; Jiang, Yuelu; Luo, Peng; Hu, Chaoqun

2014-08-30

In this study, the bioremediation potentials of two seaweeds (Sargassum hemiphyllum and S. henslowianum) against pollution in a coastal mariculture area of Shenzhen, South China, were investigated by comparing the growth, nutrient bioaccumulation capacity of plants from the seaweed bed (control site) with plants from the fish farm. Results indicated that both species are potential candidates for bioremediation in the fish farm areas in terms of their high growth rates and high bioaccumulation capacities on inorganic nutrients. Both Sargassum spp. contain high levels of crude protein (11.7-14.0%) and crude fat (2.2-2.7%), suggesting high nutritional values. The S. hemiphyllum may serve as a good aquaculture fodder with high nutritional compositions and low heavy metal contents. However, heavy metals (Cr, Pb and Cd) of S. henslowianum exceed the maximum allowable concentrations as aquatic feed, which restricts its fodder application. In general, the results of this study may contribute to the marine pollution bioremediation in the coastal areas of South China, especially in mariculture zones. Copyright © 2013 Elsevier Ltd. All rights reserved.

Occurrence of persistent organic pollutants in marine fish from the Natuna Island, South China Sea.

PubMed

Hao, Qing; Sun, Yu-Xin; Xu, Xiang-Rong; Yao, Zi-Wei; Wang, You-Shao; Zhang, Zai-Wang; Luo, Xiao-Jun; Mai, Bi-Xian

2014-08-15

Five marine fish species were collected from the Natuna Island, South China Sea to investigate the occurrence of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs). Concentrations of PBDEs, PCBs, and DDTs in marine fish ranged from 2.85 to 7.82, 14.3 to 48.1, and 7.99 to 40.3 ng/g lipid weight, respectively. Higher concentrations of PBDEs, PCBs, and DDTs were observed in Snakefish (Trachinocephalus myops), which might be attributed to their different feeding and living habits. PCBs were the predominant POPs in all marine fish, followed by DDTs and PBDEs. BDE 47 and PCB 153 were the predominant congener of PBDEs and PCBs, respectively. Compositional distribution of DDTs indicated the possible presence of fresh input sources around the Natuna Island. The ratios of o,p'-DDT/p,p'-DDT being less than 1 in fish samples suggested that DDT contributions from dicofol seemed considerably low. New input sources of DDT in South China Sea are worth further research. Copyright © 2014 Elsevier Ltd. All rights reserved.

Significant trade-off for the impact of Grain-for-Green Programme on ecosystem services in North-western Yunnan, China.

PubMed

Wang, Jitao; Peng, Jian; Zhao, Mingyue; Liu, Yanxu; Chen, Yunqian

2017-01-01

Ecological restoration can mitigate human disturbance to the natural environment and restore ecosystem functions. China's Grain-for-Green Programme (GFGP) has been widely adopted in the last 15years and exerted significant impact on land-use and ecosystem services. North-western Yunnan is one of the key areas of GFGP implementation in the upper Yangtze River. Promotion of ecosystem services in this region is of great importance to the ecological sustainability of Yangtze River watershed. In this study, remote sensing and modelling techniques are applied to analyse the impact of GFGP on ecosystem services. Results show that the transformation from non-irrigated farmland to forestland could potentially improve soil conservation by 24.89%. Soil conservation of restored forest was 78.17% of retained forest while net primary production (NPP) already reached 88.65%, which suggested different recovery rates of NPP and soil conservation. Increasing extent of GFGP implementation improved soil conservation but decreased NPP and water yield at sub-watershed scale, which revealed trade-offs between ecosystem services under ecological restoration. Future ecosystem management and GFGP policy-making should consider trade-offs of ecosystem services in order to achieve sustainable provision of ecosystem services. Copyright © 2016 Elsevier B.V. All rights reserved.

The China Factor in U.S.-Vietnam Relations

DTIC Science & Technology

2012-03-01

James Shoal off Malaysian Borneo. Vietnam also claims a sizeable portion of the South China Sea, including the Paracel and Spratly islands in their...rattled Hanoi in recent years include:  Asserting China’s ‘historic’ claim over the South China Sea: In May 2009, China rejected a joint Malaysian ...cooperate with Hanoi in offshore drilling, with a state-owned Indian firm buying out part of BP’s stake in a South China Sea joint venture with PetroVietnam

40Ar/39Ar dating of oceanic plagiogranite: Constraints on the initiation of seafloor spreading in the South China Sea

NASA Astrophysics Data System (ADS)

Zhong, Li-Feng; Cai, Guan-Qiang; Koppers, Anthony A. P.; Xu, Yi-Gang; Xu, He-Hua; Gao, Hong-Fang; Xia, Bin

2018-03-01

The Cenozoic opening of the South China Sea was one of the most significant tectonic events in SE Asia, coinciding with complex regional rifting, subduction, terrane collision, and large-scale continental strike-slip faulting. The timing of the initiation of seafloor spreading in the South China Sea remains controversial due to a scarcity of incontrovertible age data. This work provides the first report of an oceanic plagiogranite from the Penglai Seamount, located on the 17°N fossil spreading center of the East Sub-basin of the South China Sea, near the Manila Trench. Pyroxene and whole-rock 40Ar/39Ar dating yields ages of 32.3 ± 0.5 Ma and 28.9 ± 1.9 Ma, respectively. The plagiogranite show trace element and isotopic composition similar to those of mid-oceanic ridge basalts (MORB), with 87Sr/86Sr(t) = 0.70394; εNd(t) = 8.21; 206Pb/204Pb = 17.9930, 207Pb/204Pb = 15.4839, 208Pb/204Pb = 37.8852; εHf(t) = 20.95; and γOs(t) = 15.89. It suggested that the rock formed due to differential cooling between adjacent layers of oceanic crust and asthenospheric shearing at the oceanic spreading ridge, resulting in the development of detachment faults. This triggered the subsequent ingress of seawater along the faults, which transformed into a hydrothermal fluid under the influence of shear and geothermal heating, altering the parent gabbro, and leading to the generation of the daughter plagiogranite by anatexis during the early Oligocene. This new geochronology also demonstrates that the initial opening of the South China Sea occurred before 32 Ma, thereby constraining the Cenozoic tectonic evolution of Southeast Asia.

Changing character of rainfall in eastern China, 1951–2007

NASA Astrophysics Data System (ADS)

Day, Jesse A.; Fung, Inez; Liu, Weihan

2018-03-01

The topography and continental configuration of East Asia favor the year-round existence of storm tracks that extend thousands of kilometers from China into the northwestern Pacific Ocean, producing zonally elongated patterns of rainfall that we call “frontal rain events.” In spring and early summer (known as “Meiyu Season”), frontal rainfall intensifies and shifts northward during a series of stages collectively known as the East Asian summer monsoon. Using a technique called the Frontal Rain Event Detection Algorithm, we create a daily catalog of all frontal rain events in east China during 1951–2007, quantify their attributes, and classify all rainfall on each day as either frontal, resulting from large-scale convergence, or nonfrontal, produced by local buoyancy, topography, or typhoons. Our climatology shows that the East Asian summer monsoon consists of a series of coupled changes in frontal rain event frequency, latitude, and daily accumulation. Furthermore, decadal changes in the amount and distribution of rainfall in east China are overwhelmingly due to changes in frontal rainfall. We attribute the “South Flood–North Drought” pattern observed beginning in the 1980s to changes in the frequency of frontal rain events, while the years 1994–2007 witnessed an uptick in event daily accumulation relative to the rest of the study years. This particular signature may reflect the relative impacts of global warming, aerosol loading, and natural variability on regional rainfall, potentially via shifting the East Asian jet stream.

Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

NASA Astrophysics Data System (ADS)

Zhou, Zhichao; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Chen, Liang; Hao, Shihao

2018-02-01

The rift architecture and deep crustal structure of the distal margin at the mid-northern margin of the South China Sea have been previously investigated by using deep seismic reflection profiles. However, one fundamental recurring problem in the debate is the extensional fault system and rift structure of the hyperextended rift basins (Baiyun Sag and Liwan Sag) within the distal margin because of the limited amount of seismic data. Based on new 3D seismic survey data and 2D seismic reflection profiles, we observe an array of fault blocks in the Baiyun Sag, which were tilted towards the ocean by extensional faulting. The extensional faults consistently dip towards the continent. Beneath the tilted fault blocks and extensional faults, a low-angle, high-amplitude and continuous reflection has been interpreted as the master detachment surface that controls the extension process. During rifting, the continentward-dipping normal faults evolved in a sequence from south to north, generating the asymmetric rift structure of the Baiyun Sag. The Baiyun Sag is separated from the oceanic domain by a series of structural highs that were uplifted by magmatic activity in response to the continental breakup at 33 Ma and a ridge jump to the south at 26-24 Ma. Therefore, we propose that magmatism played a significant role in the continental extension and final breakup in the South China Sea.

Non-linear Internal Wave Evolution in the South China Sea: 2005 Field Program

DTIC Science & Technology

2009-05-01

Revelle in SCS05 (right). Soliton sightings from late April ( dark blue), early May (light blue) and mid May (yellow orange) are shown geographically...focus areas was the South China Sea (SCS). At that time, large-scale solitary waves were known to shoal on the western shelves of the SCS. Solitons ...we were gambling that solitons would indeed be traversing the central SCS and that they would already be well formed before reaching our approved

Cryptic genetic diversity in the mottled rabbitfish Siganus fuscescens with mitochondrial introgression at a contact zone in the South China Sea.

PubMed

Ravago-Gotanco, Rachel; de la Cruz, Talna Lorena; Pante, Ma Josefa; Borsa, Philippe

2018-01-01

The taxonomy of the mottled rabbitfish Siganus fuscescens species complex has long been challenging. In this study, we analyzed microsatellite genotypes, mitochondrial lineages, and morphometric data from 373 S. fuscescens individuals sampled from the northern Philippines and Hong Kong (South China Sea, Philippine Sea and Sulu Sea basins), to examine putative species boundaries in samples comprising three co-occurring mitochondrial lineages previously reported to characterize S. fuscescens (Clade A and Clade B) or S. canaliculatus (Clade C). We report the existence of two cryptic species within S. fuscescens in the northeast region of the South China Sea and northern Philippine Sea, supported by genetic and morphological differences. Individual-based assignment methods recovered concordant groupings of individuals into two nuclear genotype clusters (Cluster 1, Cluster 2) with (1) limited gene flow, if any, between them (FST = 0.241; P < 0.001); (2) low frequency of later-generation hybrids; (3) significant association with mitochondrial Clade A and Clade B, respectively; and (4) subtle yet significant body shape differences as inferred from geometric morphometric analysis. The divergence between mitochondrial Clade C and the two other clades was not matched by genetic differences at microsatellite marker loci. The occurrence of discordant mitonuclear combinations (20.5% of the total number of individuals) is thought to result from mitochondrial introgression, consistent with a scenario of demographic, and presumably spatial, post-Pleistocene expansion of populations from northern regions into a secondary contact zone in the South China Sea. Mitonuclear discordance due to introgression obscures phylogenetic relationships for recently-diverged lineages, and cautions against the use of mitochondrial markers alone for species identification within the mottled rabbitfish species complex in the South China Sea region.

Population genetic structure and genetic diversity of Chinese pomfret at the coast of the East China Sea and the South China Sea.

PubMed

Sun, Peng; Tang, Baojun; Yin, Fei

2018-05-01

The Chinese pomfret Pampus chinensis is one of the most economic and ecological important marine fish species in China. In the present study, the population genetic structure and genetic diversity of P. chinensis were evaluated from a total sample size of 180 individuals representing six populations from the East China Sea and the South China Sea using mitochondrial cytochrome c oxidase subunit I (COI) gene. A total of 24 variable sites (including 3 singleton sites and 21 parsimony information sites) were observed, and 18 haplotypes were defined. The haplotype diversity (Hd) of the populations ranged from 0.559 to 0.775, and the nucleotide diversity (π) ranged from 0.330 to 1.090%. Analysis of molecular variance (AMOVA) reveals that the main variation (66.02%) was among individuals within populations. The average pairwise differences and ϕ ST values indicated significant genetic differentiation between Dongxing population and the other populations. The results of the present study are helpful for the sustainable management and utilization of this species.

Decadal Transition of Moisture Sources and Transport in Northwestern China During Summer From 1982 to 2010

NASA Astrophysics Data System (ADS)

Hua, Lijuan; Zhong, Linhao; Ma, Zhuguo

2017-12-01

The northwestern corner of China (NWCC) experienced a decadal transition in summer precipitation during 1982-2010, with a significant upward trend in 1982-2000 (P1) but a downward one in 2001-2010 (P2). A spatially unbounded dynamic recycling model is developed to estimate the moisture sources and moisture transport variations based on ERA-Interim data. The results suggest that more than 88% of NWCC precipitation has external moisture origins in the southwest and northwest terrestrial areas. The increasing precipitation trend during P1 can be explained by the increasing moisture contribution from the southwest and decreasing contribution from the northwest. However, the opposite trends cause the decreasing precipitation trend during P2. In general, the decadal precipitation transition is mainly determined by the variation of short-distance moisture transport from central Asia, although opposite moisture transport variations exist in the Ural Mountains and Northeast Europe. The variation of the precipitation trend is closely associated with a well-organized wave train propagation from the North Atlantic to central Asia. During P1, the wave train structure consists of a titled positive phase North Atlantic Oscillation (NAO), an anticyclonic circulation over Europe, and a cyclonic anomaly over central Asia, which promotes the southwest moisture flux to NWCC. But the opposite circulation pattern dominates P2. The energy dispersion due to the breakdown of the NAO determines the phase and strength of the downstream wave anomalies over Eurasia. This suggests that the summer NAO might influence the decadal variation of NWCC precipitation through the decadal modulation of the Eurasia wave train.

Crop evapotranspiration-based irrigation management during the growing season in the arid region of northwestern China.

PubMed

Chang, Xuexiang; Zhao, Wenzhi; Zeng, Fanjiang

2015-11-01

In arid northwestern China, water shortages have triggered recent regulations affecting irrigation water use in desert-oasis agricultural systems. In order to determine the actual water demand of various crops and to develop standards for the rational use of water resources, we analyzed meteorological data from the Fukang desert ecosystem observation and experiment station (FKD), the Cele desert-grassland ecosystem observation and research station (CLD), and the Linze Inland River Basin Comprehensive Research Station (LZD), which all belong to the Chinese Ecosystem Research Network. We researched crop evapotranspiration (ETc) using the water balance method, the FAO-56 Penman-Monteith method, the Priestley-Taylor method, and the Hargreaves method, during the growing seasons of 2005 through 2009. Results indicate substantial differences in ETc, depending on the method used. At the CLD, the ETc from the soil water balance, FAO-56 Penman-Monteith, Priestley-Taylor, and Hargreaves methods were 1150.3±380.8, 783.7±33.6, 1018.3±22.1, and 611.2±23.3 mm, respectively; at the FKD, the corresponding results were 861.0±67.0, 834.2±83.9, 1453.5±47.1, and 1061.0±38.2 mm, respectively; and at the LZD, 823.4±110.4, 726.0±0.4, 722.3±29.4, and 1208.6±79.1 mm, respectively. The FAO-56 Penman-Monteith method provided a fairly good estimation of E Tc compared with the Priestley-Taylor and Hargreaves methods.

Estimation of subsurface formation temperature in the Yangtze area, South China: implications for shale gas generation and preservation

NASA Astrophysics Data System (ADS)

Liu, S.; Hao, C.; Li, X.; Xu, M.

2015-12-01

Temperature is one key parameter for hydrocarbon generation and preservation, also playing important role in geothermal energy assessment;however, accurate regional temperature pattern is still challenging, owing to a lack of data coverage and data quality as well. The Yangtze area, located in the South China, is considered as the most favorable target for shale gas resource exploration in China, and attracts more and more attention recently. Here we used the newly acquired steady-state temperature loggings, reliable Drilling Stem Test temperature data available and thermal properties, estimated the subsurface temperature-at-depth for the Yangtze area. Results show that the geothermal gradient ranges between 17 K/m and 74K/m, mainly falling into 20~30K/m, with a mean of 24 K/m; heat flow varies from 25 mW/m2 to 92 mW/m2, with a mean of 65 mW/m2. For the estimated temperature-at-depth, it is about 20~50 ℃ at the depth of 1000m, 50~80℃ for that at 2000m; while the highest temperature can be up to 110℃ at 3000m depth. Generally, the present-day geothermal regime of the Yangtze area is characterized by high in the northeast, low in the middle and localized high again in the southwest, and this pattern is well consistent with the tectono-thermal processes occurred in the area. Due to Cenozoic crustal extension in the northeastern Yangtze area, magmatism is prevailed, accounting for the high heat flow observed. Precambrian basement exists in the middle Yangtze area, such as the Xuefeng and Wuling Mountains, heat flow and subsurface temperature accordingly show relatively low as well. While for the southwestern Yangtze area, especially Yunnan and western Sichuan provinces, localized Cenozoic magmatism and tectonic activities are available, which is attributed to the high geothermal regime there. Considering the Paleozoic intensive tectonic deformation in the Yangtze area, tectonically stable area is prerequisite for shale gas preservation. Geothermal regime analysis

Understanding the Tectonic Features in the South China Sea By Analyzing Magnetic Anomalies

NASA Astrophysics Data System (ADS)

Guo, L.; Meng, X.; Shi, L.; Yao, C.

2011-12-01

The South China Sea (SCS) is surrounded by the Eurasia, Pacific and India-Australia plates. It formed during Late Oligocene-Early Miocene, and is one of the largest marginal seas in the Western Pacific. The collision of Indian subcontinent and Eurasian plate in the northwest, back-arc spreading in the centre and subduction beneath the Philippine plate along Manila trench in the east and along Palawan trough in the south had produced the complex tectonic features in the SCS that we can see today. In the past few decades, a variety of geophysical methods were conducted to study geological tectonics and evolution of the SCS. Here, we analyzed the magnetic data of this area using new data enhancement techniques to understand the regional tectonic features. We assembled the magnetic anomalies data with a resolution of two arc-minute from the World Digital Magnetic Anomaly Map, and then gridded the data on a regular grid. Then we used the method of reduction to the pole at low latitude with varying magnetic inclinations to stably reduce the magnetic anomalies. Then we used the preferential continuation method based on Wiener filtering and Green's equivalence principle to separate the reduced-to-pole (RTP) magnetic anomalies, and subsequently analyze the regional and residual anomalies. We also calculated the directional horizontal derivatives and the tilt-angle derivative of the data to derive clearer geological structures with more details. Then we calculated the depth of the magnetic basement surface in the area by 3D interface inversion. From the results of the preliminary processing, we analyzed the main faults, geological structures, magma distribution and tectonic features in the SCS. In the future, the integrated interpretation of the RTP magnetic anomalies, Bouguer gravity anomalies and other geophysical methods will be performed for better understanding the deep structure , the tectonic features and evolution of the South China Sea. Acknowledgment: We

Increasing persistent haze in Beijing: potential impacts of weakening East Asian winter monsoons associated with northwestern Pacific sea surface temperature trends

NASA Astrophysics Data System (ADS)

Pei, Lin; Yan, Zhongwei; Sun, Zhaobin; Miao, Shiguang; Yao, Yao

2018-03-01

Over the past decades, Beijing, the capital city of China, has encountered increasingly frequent persistent haze events (PHE). While the increased pollutant emissions are considered as the most important reason, changes in regional atmospheric circulations associated with large-scale climate warming also play a role. In this study, we find a significant positive trend of PHE in Beijing for the winters from 1980 to 2016 based on updated daily observations. This trend is closely related to an increasing frequency of extreme anomalous southerly episodes in North China, a weakened East Asian trough in the mid-troposphere and a northward shift of the East Asian jet stream in the upper troposphere. These conditions together depict a weakened East Asian winter monsoon (EAWM) system, which is then found to be associated with an anomalous warm, high-pressure system in the middle-lower troposphere over the northwestern Pacific. A practical EAWM index is defined as the seasonal meridional wind anomaly at 850 hPa in winter over North China. Over the period 1900-2016, this EAWM index is positively correlated with the sea surface temperature anomalies over the northwestern Pacific, which indicates a wavy positive trend, with an enhanced positive phase since the mid-1980s. Our results suggest an observation-based mechanism linking the increase in PHE in Beijing with large-scale climatic warming through changes in the typical regional atmospheric circulation.

Virtual versus real water transfers within China.

PubMed

Ma, Jing; Hoekstra, Arjen Y; Wang, Hao; Chapagain, Ashok K; Wang, Dangxian

2006-05-29

North China faces severe water scarcity--more than 40% of the annual renewable water resources are abstracted for human use. Nevertheless, nearly 10% of the water used in agriculture is employed in producing food exported to south China. To compensate for this 'virtual water flow' and to reduce water scarcity in the north, the huge south-north Water Transfer Project is currently being implemented. This paradox--the transfer of huge volumes of water from the water-rich south to the water-poor north versus transfer of substantial volumes of food from the food-sufficient north to the food-deficit south--is receiving increased attention, but the research in this field has not yet reached further than rough estimation and qualitative description. The aim of this paper is to review and quantify the volumes of virtual water flows between the regions in China and to put them in the context of water availability per region. The analysis shows that north China annually exports about 52 billion m3 of water in virtual form to south China, which is more than the maximum proposed water transfer volume along the three routes of the Water Transfer Project from south to north.

Two new species of Kamimuria (Plecoptera: Perlidae) from Shaanxi Province, China.

PubMed

Li, Weihai; Mo, Raorao

2018-02-15

Two new species of the perlid genus Kamimuria Klapálek, K. shaanxinensis sp. nov. and K. yangxiana sp. nov. from Shaanxi Province of northwestern China are described in this paper. The similar characteristics of the new species and related taxa are discussed.

An epidemiological study of sleep quality in adolescents in South China: a school-based study.

PubMed

Zhou, H-Q; Shi, W-B; Wang, X-F; Yao, M; Cheng, G-Y; Chen, P-Y; Li, D-G

2012-07-01

This study explored the prevalence of disturbed sleep and investigated its distribution characteristics and associated factors in adolescents in South China. Junior middle school and senior high school students (n = 1221) were recruited from schools in Shanghai, China. Students completed a questionnaire using the Pittsburgh Sleep Quality Index and factors associated with disturbed sleep. The prevalence of a tendency towards poor sleep was 34.32% [95% confidence interval (CI): 31.66-36.98] with no significant difference between genders. This tendency increased with age, yielding a significant group effect (P < 0.01). In middle school and high school, the propensity towards poor sleep was 31.34% (95% CI: 28.29-34.39) and 42.22% (95% CI: 36.92-47.52) respectively. The factors associated with poor sleep were more television viewing during weekdays [odds ratio (OR): 1.56, CI: 1.36-1.71], more frequent computer/Internet use (OR: 1.25, CI: 1.08-1.39), earlier school starting time (OR: 1.12, CI: 1.07-1.28), and more time on homework during weekdays (OR: 1.78, CI: 1.51-1.98) and weekends (OR: 1.35, CI: 1.21-1.52) A tendency towards poor sleep is common in adolescents in South China and its incidence increases with age. The factors associated with this phenomenon indicate that poor sleep in adolescents could be improved, at least partly, by reducing the use of visual technologies and by changing school timetables. © 2011 Blackwell Publishing Ltd.

Impacts of mesoscale eddies on biogeochemical cycles in the South China Sea

NASA Astrophysics Data System (ADS)

Xiu, P.; Chai, F.; Guo, M.

2016-02-01

Biogeochemical cycles associated with mesoscale eddies in the South China Sea (SCS) are investigated by using satellite surface chlorophyll concentration, altimeter data, satellite sea surface temperature, and a coupled physical-biogeochemical Pacific Ocean model (ROMS-CoSiNE) simulation for the period from 1991 to 2007. Considering the annual mean, composite analysis reveals that cyclonic eddies are associated with higher concentrations of nutrients, phytoplankton and zooplankton while the anticyclonic eddies are with lower concentrations compared with surrounding waters, which is generally controlled by the eddy pumping mechanism. Dipole structures of vertical fluxes with net upward motion in cyclonic eddies and net downward motion in anticyclonic eddies are also revealed. During the lifetime of an eddy, the evolutions of physical, biological, and chemical structures are not linearly coupled at the eddy core where plankton grow and composition of the community depend not only on the physical and chemical processes but also on the adjustments by the predator-prey relationship. Considering the seasonal variability, we find eddy pumping mechanisms are generally dominant in winter and eddy advection effects are dominant in summer. Over the space, variability of chlorophyll to the west of Luzon Strait and off northwest of Luzon Island are mainly controlled by eddy pumping mechanism. In regions off the Vietnam coast, chlorophyll distributions are generally associated with horizontal eddy advection. This research highlights different mesoscale mechanisms affecting biological structures that can potentially disturb ocean biogeochemical cycling processes in the South China Sea.

Contrasting Photophysiological Characteristics of Phytoplankton Assemblages in the Northern South China Sea.

PubMed

Jin, Peng; Gao, Guang; Liu, Xin; Li, Futian; Tong, Shanying; Ding, Jiancheng; Zhong, Zhihai; Liu, Nana; Gao, Kunshan

2016-01-01

The growth of phytoplankton and thus marine primary productivity depend on photophysiological performance of phytoplankton cells that respond to changing environmental conditions. The South China Sea (SCS) is the largest marginal sea of the western Pacific and plays important roles in modulating regional climate and carbon budget. However, little has been documented on photophysiological characteristics of phytoplankton in the SCS. For the first time, we investigated photophysiological characteristics of phytoplankton assemblages in the northern South China Sea (NSCS) using a real-time in-situ active chlorophyll a fluorometry, covering 4.0 × 105 km2. The functional absorption cross section of photosystem II (PSII) in darkness (σPSII) or under ambient light (σPSII') (A2 quanta-1) increased from the surface to deeper waters at all the stations during the survey period (29 July to 23 August 2012). While the maximum (Fv/Fm, measured in darkness) or effective (Fq'/Fm', measured under ambient light) photochemical efficiency of PSII appeared to increase with increasing depth at most stations, it showed inverse relationship with depth in river plume areas. The functional absorption cross section of PSII changes could be attributed to light-adapted genotypic feature due to niche-partition and the alteration of photochemical efficiency of PSII could be attributed to photo-acclimation. The chlorophyll a fluorometry can be taken as an analog to estimate primary productivity, since areas of higher photochemical efficiency of PSII coincided with those of higher primary productivity reported previously in the NSCS.

Multilocus genotyping of Giardia duodenalis and Enterocytozoon bieneusi in dairy and native beef (Qinchuan) calves in Shaanxi province, northwestern China.

PubMed

Wang, X T; Wang, R J; Ren, G J; Yu, Z Q; Zhang, L X; Zhang, S Y; Lu, H; Peng, X Q; Zhao, G H

2016-03-01

Giardia duodenalis and Enterocytozoon bieneusi are two common protozoa that parasitize the intestinal epithelium of animals and humans. Calves have been identified as important reservoirs of these two pathogens, but limited data is available for these two pathogens in calves in China. In the present study, the prevalence and assemblages/genotypes of both parasites in calves of dairy and native beef (Qinchuan) cattle in Shaanxi province, northwestern China, were analyzed using multilocus genotyping (MLST). Of 371 fecal samples collected from calves (including 198 dairy calves and 173 Qinchuan calves), the respective overall prevalence of G. duodenalis and E. bieneusi was 18.87 (70 of 371) and 19.68 % (73 of 371). Both the zoonotic G. duodenalis assemblage A and animal adapted assemblage E were found in dairy and Qinchuan calves. Seventeen, eight, five, and two G. duodenalis subtypes were detected at the triose phosphate isomerase (tpi), β-giardin (bg), glutamate dehydrogenase (gdh), and small subunit ribosomal RNA (SSU-rRNA) loci, with five and two novel subtypes detected at the tpi and bg loci, forming 25 multiple genotypes (MLGs) (15 and 11 in dairy and Qinchuan calves, respectively). Of 73 samples that were positive for E. bieneusi at the ribosomal RNA internal transcribed spacer (ITS) locus, five ITS genotypes were found, including three known zoonotic genotypes (I, J, CHN1) and two novel genotypes (CSX1 and CSX2). MLST analysis of three microsatellite loci (MS1, MS3, MS7) and one minisatellite locus (MS4) detected six, two, two, and two genotypes at the MS1, MS3, MS4, and MS7 loci, respectively, forming ten MLGs (seven and four in dairy and Qinchuan calves, respectively). These results indicate complex population structures of G. duodenalis and E. bieneusi in calves in Shaanxi province and the zoonotic potential of these two pathogens in calves in this province.

Mobile LiDAR Measurement for Aerosol Investigation in South-Central Hebei, China

NASA Astrophysics Data System (ADS)

qin, kai; Wu, Lixin; Zheng, Yunhui; Wong Man, Sing; Wang, Runfeng; Hu, Mingyu; Lang, Hongmei; Wang, Luyao; Bai, Yang; Rao, Lanlan

2016-04-01

With the rapid industrialization and urbanization in China during the last decades, the increasing anthropogenic pollutant emissions have significantly caused serious air pollution problems which are adversely influencing public health. Hebei is one of the most air polluted provinces in China. In January 2013, an extremely severe and persistent haze episode with record-breaking PM2.5 outbreak affecting hundreds of millions of people occurred over eastern and northern China. During that haze episode, 7 of the top 10 most polluted cities in China were located in the Hebei Province according to the report of China's Ministry of Environmental Protection. To investigate and the spatial difference and to characterize the vertical distribution of aerosol in different regions of south-central Hebei, mobile measurements were carried out using a mini micro pulse LiDAR system (model: MiniMPL) in March 2014. The mobile LiDAR kit consisting of a MiniMPL, a vibration reduction mount, a power inverter, a Windows surface tablet and a GPS receiver were mounted in a car watching though the sunroof opening. For comparison, a fixed measurement using a traditional micro pulse LiDAR system (model: MPL-4B) was conducted simultaneously in Shijiazhuang, the capital of Hebei Province. The equipped car was driven from downtown Shijiazhuang by way of suburban and rural area to downtown Cangzhou, Handan, and Baoding respectively at almost stable speed around 100Km per hour along different routes which counted in total more than 1000Km. The results can be summarized as: 1) the spatial distribution of total aerosol optical depth along the measurement routes in south-central Hebei was controlled by local terrain and population in general, with high values in downtown and suburban in the plain areas, and low values in rural areas along Taihang mountain to the west and Yan mountain to the north; 2) obviously high AODs were obtained at roads crossing points, inside densely populated area and nearby

Academia Sinica, TW E-science to Assistant Seismic Observations for Earthquake Research, Monitor and Hazard Reduction Surrounding the South China Sea

NASA Astrophysics Data System (ADS)

Huang, Bor-Shouh; Liu, Chun-Chi; Yen, Eric; Liang, Wen-Tzong; Lin, Simon C.; Huang, Win-Gee; Lee, Shiann-Jong; Chen, Hsin-Yen

Experience from the 1994 giant Sumatra earthquake, seismic and tsunami hazard have been considered as important issues in the South China Sea and its surrounding region, and attracted many seismologist's interesting. Currently, more than 25 broadband seismic instruments are currently operated by Institute of Earth Sciences, Academia Sinica in northern Vietnam to study the geodynamic evolution of the Red river fracture zone and rearranged to distribute to southern Vietnam recently to study the geodynamic evolution and its deep structures of the South China Sea. Similar stations are planned to deploy in Philippines in near future. In planning, some high quality stations may be as permanent stations and added continuous GPS observations, and instruments to be maintained and operated by several cooperation institutes, for instance, Institute of Geophysics, Vietnamese Acadamy of Sciences and Technology in Vietnam and Philippine Institute of Volcanology and Seismology in Philippines. Finally, those stations will be planed to upgrade as real time transmission stations for earthquake monitoring and tsunami warning. However, high speed data transfer within different agencies is always a critical issue for successful network operation. By taking advantage of both EGEE and EUAsiaGrid e-Infrastructure, Academia Sinica Grid Computing Centre coordinates researchers from various Asian countries to construct a platform to high performance data transfer for huge parallel computation. Efforts from this data service and a newly build earthquake data centre for data management may greatly improve seismic network performance. Implementation of Grid infrastructure and e-science issues in this region may assistant development of earthquake research, monitor and natural hazard reduction. In the near future, we will search for new cooperation continually from the surrounding countries of the South China Sea to install new seismic stations to construct a complete seismic network of the

Simulating seasonal tropical cyclone intensities at landfall along the South China coast

NASA Astrophysics Data System (ADS)

Lok, Charlie C. F.; Chan, Johnny C. L.

2018-04-01

A numerical method is developed using a regional climate model (RegCM3) and the Weather Forecast and Research (WRF) model to predict seasonal tropical cyclone (TC) intensities at landfall for the South China region. In designing the model system, three sensitivity tests have been performed to identify the optimal choice of the RegCM3 model domain, WRF horizontal resolution and WRF physics packages. Driven from the National Centers for Environmental Prediction Climate Forecast System Reanalysis dataset, the model system can produce a reasonable distribution of TC intensities at landfall on a seasonal scale. Analyses of the model output suggest that the strength and extent of the subtropical ridge in the East China Sea are crucial to simulating TC landfalls in the Guangdong and Hainan provinces. This study demonstrates the potential for predicting TC intensities at landfall on a seasonal basis as well as projecting future climate changes using numerical models.

HYDROLOGIC CHARACTERISTICS OF A MANAGED WETLAND AND A NATURAL RIVERINE WETLAND ALONG THE KANKAKEE RIVER IN NORTHWESTERN INDIANA. SCIENTIFIC INVESTIGATIONS REPORT 2006-5222.

EPA Science Inventory

Characteristics of ground-water/surface-water interactions were identified at a managed wetland (Hog Marsh) and a natural riverine wetland (LaSalle) located on the north and south sides, respectively, of the Kankakee River in northwestern Indiana. Hog Marsh covers about 390 hecta...

China Emerging

DTIC Science & Technology

2012-03-14

historical components to the disputes in the South China Sea that have bearing on the issue. China, Taiwan, Vietnam, Malaysia , the Philippines...government for needed efficiency. It becomes more and more untenable for an authoritative government to enforce censorship , political repression, state

Variation of phytoplankton community structure from the Pearl River estuary to South China Sea.

PubMed

Jiang, Zhao-Yu; Wang, You-Shao; Cheng, Hao; Sun, Cui-Ci; Wu, Mei-Lin

2015-10-01

The Pearl River is located in the northern part of South China Sea. The environment of the Pearl River estuary (PRE) is significantly impacted by nutrients from anthropogenic activities. Along the anthropogenic pollution gradient from the PRE to South China Sea, the phylogenetic diversity and biomass of phytoplankton was examined in relation to physic-chemical variables. The richness of rbcL gene was higher in the open sea than the estuary, while the concentration of chlorophyll a (Chl a) was higher in the estuary than in the open sea. The cluster analysis of the sequences data resulted in seven phytoplankton community types and the dominant species of phytoplankton changed from Cryptophytes and Diatoms to Prymnesiophytes and Diatoms along the gradient. The community structure of phytoplankton was shaped by nutrients and salinity. The phytoplankton biomass was significantly positively affected by phosphorus, nitrite and ammonium (P < 0.01) but negatively by salinity (P < 0.05); the phytoplankton diversity was highly positively affected by salinity (P < 0.05) but negatively by silicate and nitrate (P < 0.01; P < 0.05, respectively). Anthropogenic activities played a critical role in the phytoplankton distribution and biomass of the study area. Further research is necessary to reveal the influence mechanism of environmental factors on the phytoplankton.

Kinematic parameters of internal waves of the second mode in the South China Sea

NASA Astrophysics Data System (ADS)

Kurkina, Oxana; Talipova, Tatyana; Soomere, Tarmo; Giniyatullin, Ayrat; Kurkin, Andrey

2017-10-01

Spatial distributions of the main properties of the mode function and kinematic and non-linear parameters of internal waves of the second mode are derived for the South China Sea for typical summer conditions in July. The calculations are based on the Generalized Digital Environmental Model (GDEM) climatology of hydrological variables, from which the local stratification is evaluated. The focus is on the phase speed of long internal waves and the coefficients at the dispersive, quadratic and cubic terms of the weakly non-linear Gardner model. Spatial distributions of these parameters, except for the coefficient at the cubic term, are qualitatively similar for waves of both modes. The dispersive term of Gardner's equation and phase speed for internal waves of the second mode are about a quarter and half, respectively, of those for waves of the first mode. Similarly to the waves of the first mode, the coefficients at the quadratic and cubic terms of Gardner's equation are practically independent of water depth. In contrast to the waves of the first mode, for waves of the second mode the quadratic term is mostly negative. The results can serve as a basis for expressing estimates of the expected parameters of internal waves for the South China Sea.

Analysis and design of trial well mooring in deepwater of the South China Sea

NASA Astrophysics Data System (ADS)

Guo, Yongfeng; Ji, Shaojun; Tang, Changquan; Li, Jiansong; Zhong, Huiquan; Ian, Ong Chin Yam

2012-06-01

Mooring systems play an important role for semi-submersible rigs that drill in deepwater. A detailed analysis was carried out on the mooring of a semi-submersible rig that conducted a trial well drilling at a deepwater location in the South China Sea in 2009. The rig was 30 years old and had a shallow platform with a designed maximum operating water depth of 457 m. Following the mooring analysis, a mooring design was given that requires upgrading of the rig's original mooring system. The upgrade included several innovations, such as installing eight larger anchors, i.e. replacing the original anchors and inserting an additional 600 m of steel wires with the existing chains. All this was done to enhance the mooring capability of the rig in order for the rig to be held in position to conduct drilling at a water depth of 476 m. The overall duration of the drilling was 50 days and the upgraded mooring system proved to be efficient in achieving the goal of keeping the rig stationary while it was drilling the trial well in the South China Sea. This successful campaign demonstrates that an older semi-submersible rig can take on drilling in deep water after careful design and proper upgrading and modification to the original mooring system.

Environmental water chemistry and possible correlation with Kaschin-Beck Disease (KBD) in northwestern Sichuan, China.

PubMed

Shi, Zeming; Pan, Pujing; Feng, Yanwei; Kan, Zezhong; Li, Zhonghui; Wei, Fei

2017-02-01

During the past several decades, etiological and geochemical studies tend to link the Kaschin-Beck Disease (KBD) to the deficiency of some specific trace elements (e.g., selenium and iodine) in the environment; however the link has been proven inconclusive. In this work, we have investigated the relationship between KBD and the environment in a broader scope by examining comprehensively the chemistry of the surface waters in northwestern Sichuan, China, in relation to the KBD prevalence. The surface waters in the study area were found to be near neutral to slightly alkaline (pH6.70 to 8.85 with a mean of 7.91) and mostly soft (total hardness 35.2 to 314.3mg/L, mean 118.8mg/L) with low salinity (total dissolved solids (TDS) 44.5mg/L to 376.6mg/L, mean 146.6mg/L). The waters were dominated by cations Ca 2+ and Mg 2+ and anion HCO 3 - ; whereas the alkali metal ions K + and Na + and the anions Cl - and S0 4 2- were relatively scarce. Spatially, the hardness/salinity of the surface waters exhibited a characteristic of being lower towards the center of the study area where most severe KBD endemic has been observed. Even though it is not conclusive at this stage, a correlation between KBD prevalence and the salinity/hardness of the surface waters of an area has been demonstrated. As a postulate, the long-term consumption of such low salinity waters may lead to a deficiency of some essential elements such as Ca, Mg, Se and I in humans, which may be a factor in inducing KBD. However, other factors such as high altitude and cold climate, poor nutrition and sanitary conditions may play an important role in the disease endemic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Salinification in the South China Sea Since Late 2012: A Reversal of the Freshening Since the 1990s

NASA Astrophysics Data System (ADS)

Zeng, Lili; Chassignet, Eric P.; Schmitt, Raymond W.; Xu, Xiaobiao; Wang, Dongxiao

2018-03-01

Salinification has occurred in the South China Sea from late 2012 to the present, as shown by satellite Aquarius/Soil Moisture Active Passive data and Argo float data. This salinification follows a 20 year freshening trend that started in 1993. The salinification signal is strongest near the surface and extends downward under the seasonal thermocline to a depth of 150 m. The salinification occurs when the phase of the Pacific Decadal Oscillation switches from negative to positive. Diagnosis of the salinity budget suggests that an increasing net surface freshwater loss and the horizontal salt advection through the Luzon Strait driven by the South China Sea throughflow contributed to this ongoing salinification. In particular, a decrease in precipitation and enhanced Luzon Strait transport dominated the current intense salinification. Of particular interest is whether this salinification will continue until it reaches the previous maximum recorded in 1992.

Feature analysis and primary causes of pre-flood season "cumulative effect" of torrential rain over South China

NASA Astrophysics Data System (ADS)

Chu, Qu-cheng; Wang, Qi-guang; Qiao, Shao-bo; Feng, Guo-lin

2018-01-01

When persistent rainfall occurs frequently over South China, meso-scale and micro-scale synoptic systems persist and expand in space and time and eventually form meso-scale and long-scale weather processes. The accumulation of multiple torrential rain processes is defined as a "cumulative effect" of torrential rain (CETR) event. In this paper, daily reanalysis datasets collected by the National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) during 1979-2014 are used to study the anomalous features and causes of heavy CETR events over South China. The results show that there is a significant difference in the spatial distribution of the heavy CETR events. Based on the center position of the CETR, the middle region displayed middle-region-heavy CETR events while the western region displayed west-region-heavy CETR events. El Niño events in the previous period (December, January, February, March (DJFM)) are major extra-forcing factors of middle-region-heavy CETR events, which is beneficial for the continuous, anomalous Philippine Sea anticyclone and strengthens the West Pacific Subtropical High (WPSH), extending it more westward than normal. The primary water vapor source for precipitation in middle-region-heavy CETR events is the Tropical Western Pacific Ocean. The major extra-forcing factor of a west-region-heavy CETR is the negative anomaly in the southern Tropical Indian Ocean (TIO) during the previous period (DJFM). This factor is beneficial for strengthening the cross-equatorial flow and westerly winds from the Bay of Bengal to the South China Sea (SCS) and early SCS summer monsoon onset. The primary water vapor source of precipitation in the west-region-heavy CETR is the southern TIO.

Distribution of Bathyarchaeota (MCG) archaea in the South China Sea sediments and implication of its ecological roles

NASA Astrophysics Data System (ADS)

Tiantian, Y.; Wang, F.; MingYang, N.

2015-12-01

Tiantian Yu1,2, Mingyang Niu1,2 and Fengping Wang1,2 1State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai, 200240, China; 2State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China ABSTRACT: Archaea of Bathyarchaeota Phylum (Miscellaneous Crenarchaeotal Group, MCG) are widespread and abundant in various marine and continental environments. However, very little is understood on the metabolisms and ecological roles of this cosmopolitan sedimentary archaea , partly due to obstacles of cultivation. Bathyarchaeota could be divided into large members of subgroups with potentially high genetic heterogeneity, implying different metabolic capabilities and functions in different subgroups. Here, we report our work on investigating Bathyarchaeota abundance and types of subgroups in the South China Sea(SCS) sediments, aim to understand their ecological roles in the carbon cycling. Bathyarchaeota were found the most dominant archaeal group in the sediments of SCS , most of which belong to subgroups MCG-8, MCG-15, MCG-17 and MCG-3. A new pair of 16S rRNA gene primers was designed as the published primers could not cover MCG-15 and MCG-17, which are the most dominant subgroups in the SCS sediments. Comparing with previous primers which used for quantifying the abundance of Bathyarchaeota via Q-PCR, the new primer revealed about an order of magnitude higher abundance in all South China Sea sediments. The relationship of geochemical parameters and MCG subgroups will further be explored to provide the basis for further understanding the metabolic function and biogeochemical roles of these poor-understood sedimentary archaea.

Two new species of Hexactinellida (Porifera) from the South China Sea.

PubMed

Gong, Lin; Li, Xinzheng; Qiu, Jian-Wen

2015-10-28

In this paper, two new sponge species, Semperella jiaolongae sp. nov. (Amphidiscosida, Pheronematidae) and Saccocalyx microhexactin sp. nov. (Lyssacinosida, Euplectellidae) are described based on materials from the South China Sea. Semperella jiaolongae sp. nov. is diagnosed mainly by the dermal areas present on both sides of the body, occurring together with atrial areas randomly distributed on one side, and the distinctive shape of micropentactins. Saccocalyx microhexactin sp. nov. is characterized by possession of two types of drepanocomes and one of microhexactins. An analysis based on partial sequence of the 16S rRNA gene was undertaken to show the congruence between morphological identification and phylogenetic classification of the two new species.

Distribution and abundance of Anoplophora glabripennis in stands of its native host in South Korea and China

Treesearch

David W. Williams; Hai-Poong Lee

2003-01-01

Following up on our discovery in 2000 that Acer mono is a native host of Anoplophora glabripennis, we spent eight weeks searching for the beetle in natural forest stands in South Korea and China. We wanted to assess the distribution and abundance of beetles in closed forest stands of native hosts.

A reanalysis dataset of the South China Sea.

PubMed

Zeng, Xuezhi; Peng, Shiqiu; Li, Zhijin; Qi, Yiquan; Chen, Rongyu

2014-01-01

Ocean reanalysis provides a temporally continuous and spatially gridded four-dimensional estimate of the ocean state for a better understanding of the ocean dynamics and its spatial/temporal variability. Here we present a 19-year (1992-2010) high-resolution ocean reanalysis dataset of the upper ocean in the South China Sea (SCS) produced from an ocean data assimilation system. A wide variety of observations, including in-situ temperature/salinity profiles, ship-measured and satellite-derived sea surface temperatures, and sea surface height anomalies from satellite altimetry, are assimilated into the outputs of an ocean general circulation model using a multi-scale incremental three-dimensional variational data assimilation scheme, yielding a daily high-resolution reanalysis dataset of the SCS. Comparisons between the reanalysis and independent observations support the reliability of the dataset. The presented dataset provides the research community of the SCS an important data source for studying the thermodynamic processes of the ocean circulation and meso-scale features in the SCS, including their spatial and temporal variability.

New species, hyper-diversity and potential importance of Calonectria spp. from Eucalyptus in South China

PubMed Central

Lombard, L.; Chen, S.F.; Mou, X.; Zhou, X.D.; Crous, P.W.; Wingfield, M.J.

2015-01-01

Plantation forestry is expanding rapidly in China to meet an increasing demand for wood and pulp products globally. Fungal pathogens including species of Calonectria represent a serious threat to the growth and sustainability of this industry. Surveys were conducted in the Guangdong, Guangxi and Hainan Provinces of South China, where Eucalyptus trees in plantations or cuttings in nurseries displayed symptoms of leaf blight. Isolations from symptomatic leaves and soils collected close to infected trees resulted in a large collection of Calonectria isolates. These isolates were identified using the Consolidated Species Concept, employing morphological characters and DNA sequence comparisons for the β-tubulin, calmodulin, histone H3 and translation elongation factor 1-alpha gene regions. Twenty-one Calonectria species were identified of which 18 represented novel taxa. Of these, 12 novel taxa belonged to Sphaero-Naviculate Group and the remaining six to the Prolate Group. Southeast Asia appears to represent a centre of biodiversity for the Sphaero-Naviculate Group and this fact could be one of the important constraints to Eucalyptus forestry in China. The remarkable diversity of Calonectria species in a relatively small area of China and associated with a single tree species is surprising. PMID:26955194

Vertical distribution and sources of tropospheric ozone over South China in spring 2004: Ozonesonde measurements and modeling analysis

NASA Astrophysics Data System (ADS)

Zhang, Y.; Liu, H.; Crawford, J. H.; Considine, D. B.; Chan, C.; Scientific Team Of Tapto

2010-12-01

The Transport of Air Pollutant and Tropospheric Ozone over China (TAPTO-China) science initiative is a two-year (TAPTO 2004 and 2005) field measurement campaign to help improve our understanding of the physical and chemical processes that control the tropospheric ozone budget over the Chinese subcontinent (including the Asian Pacific rim) and its surrounding SE Asia. In this paper, we use two state-of-the-art 3-D global chemical transport models (GEOS-Chem and Global Modeling Initiative or GMI) to examine the characteristics of vertical distribution and quantify the sources of tropospheric ozone by analysis of TAPTO in-situ ozonesonde data obtained at five stations in South China during spring (April and May) 2004: Lin’an (30.30N, 119.75E), Tengchong (25.01N, 98.30E), Taipei (25.0N, 121.3E), Hong Kong (22.21N, 114.30E) and Sanya (18.21N, 110.31E). The observed tropospheric ozone concentrations show strong spatial and temporal variability, which is largely captured by the models. The models simulate well the observed vertical gradients of tropospheric ozone at higher latitudes but are too low at lower latitudes. Model tagged ozone simulations suggest that stratosphere has a large impact on the upper and middle troposphere (UT/MT) at Lin’an and Tengchong. Continental SE Asian biomass burning emissions are maximum in March but still contribute significantly to the photochemical production of tropopheric ozone in South China in early April. Asian anthropogenic emissions are the major contribution to lower tropospheric ozone at all stations. On the other hand, there are episodes of influence from European/North American anthropogenic emissions. For example, model tagged ozone simulations show that over Lin’an in April 2004, stratosphere contributes 20% (13 ppbv) at 5 km, Asian boundary layer contributes 70% (46 ppbv) to ozone in the boundary layer, European boundary layer contributes 5% (3-4 ppbv) at 1.2 km, and North American boundary layer contributes 4.5% (3

The rapid cooling of the Nansha Block, southern South China Sea

NASA Astrophysics Data System (ADS)

Dong, M.; Zhang, J.

2017-12-01

Since the Late Cretaceous and Cenozoic, the Nansha Block has experienced a series of tectonic process and separated from South China continent to the south. As an exotic micro-continental, Nansha Block has an obvious different lithospheric rheology property from surrounding region. The lithosphere and mantle dynamic and rheology are mainly controlled by temperature. Therefore, we calculated the 3D temperature field and geothermal gradient of Nansha Block's upper mantle by using the S-wave velocity structure from surface wave tomography. The results show that the depth where temperature of 1300° as the lithospheric thickness is in close correspondence with the top of the seismic low velocity zone. The temperature of the upper mantle in Nansha Block is significantly lower than that of surrounding. It implies that Nansha Block experienced a rapid cooling event. We propose that the rapid cooling can be partly attributed to three reasons: 1) Nansha Block is a relatively stable block with no interior geothermal activity. 2) No external heat source to provide energy. 3) Abnormal mantle convection under Nansha Block accelerated the cooling.

Seismic imaging of Late Cretaceous magmatic system in the northern margin of South China Sea

NASA Astrophysics Data System (ADS)

Xia, S.; Xu, H.; Sun, J.; Zhao, F.; Fan, C.

2017-12-01

The origin and evolution of magmatism in the rifting margins are the fundamentally geological subjects, and remain the focus of intense study. Different from the classical volcanic or nonvolcanic rifting margins, the northern margin of South China Sea (SCS) experienced uniquely regional tectonic processes, and formed plentiful intraplate seamounts mainly at the postrift period. There is considerable controversy over what caused the intensively postrift intraplate volcanism. Here we combine a new crustal structure with previously systematic petrologic and seismic tomographic results to first provide importantly new insights into a mantle plume origin and complex multilevel plumbing system of intraplate seamounts in the northern margin of SCS. Large amounts of active melts from the lower mantle migrated upward and reached the base of the lithosphere. The volatile-rich and overheated magmas continued ascending along the weak zone through the lithosphere and intruded into the lower crust. The intrusion magmas then ascended forward along the faults formed during the rifting, and supplied the magma source for the formation of intraplate seamounts in the northern margin of SCS. It supplies an important implication for the volume and range of late Cenozoic basaltic magmatism deriving from the Hainan mantle plume. Keywords: South China Sea; Late Cretaceous; Magmatic System; Hainan Plume AcknowledgementsThe field work of this study was assisted by the captain and crew of the R/V Shiyan 2. Prof. Xuelin Qiu supplied great helps for the successful implementation of the cruise. This work was partially supported by grants from the National Natural Science Foundation of China (Grant Nos. 91328206 and 41576041).

Modeling nitrate leaching and optimizing water and nitrogen management under irrigated maize in desert oases in Northwestern China.

PubMed

Hu, Kelin; Li, Yong; Chen, Weiping; Chen, Deli; Wei, Yongping; Edis, Robert; Li, Baoguo; Huang, Yuanfang; Zhang, Yuanpei

2010-01-01

Understanding water and N transport through the soil profile is important for efficient irrigation and nutrient management to minimize nitrate leaching to the groundwater, and to promote agricultural sustainable development in desert oases. In this study, a process-based water and nitrogen management model (WNMM) was used to simulate soil water movement, nitrate transport, and crop growth (maize [Zea mays L.]) under desert oasis conditions in northwestern China. The model was calibrated and validated with a field experiment. The model simulation results showed that about 35% of total water input and 58% of the total N input were leached to <1.8 m depth under traditional management practice. Excessive irrigation and N fertilizer application, high nitrate concentration in the irrigation water, together with the sandy soil texture, resulted in large nitrate leaching. Nitrate leaching was significantly reduced under the improved management practice suggested by farm extension personnel; however, the water and nitrate inputs still far exceeded the crop requirements. More than 1700 scenarios combining various types of irrigation and fertilizer practices were simulated. Quantitative analysis was conducted to obtain the best management practices (BMPs) with simultaneous consideration of crop yield, water use efficiency, fertilizer N use efficiency, and nitrate leaching. The results indicated that the BMPs under the specific desert oasis conditions are to irrigate the maize with 600 mm of water in eight times with a single fertilizer application at a rate of 75 kg N ha(-1).

Shelf-Scale Submarine Groundwater Discharge in the Northern South China Sea and East China Sea and its Geochemical Impacts

NASA Astrophysics Data System (ADS)

Tan, Ehui; Wang, Guizhi; Moore, Willard S.; Li, Qing; Dai, Minhan

2018-04-01

To evaluate biogeochemical impacts of shelf-scale submarine groundwater discharge (SGD), the northern South China Sea (NSCS) and the East China Sea (ECS) shelf were chosen for this study. Based on a three end-member mixing model and a Ra box model, SGD fluxes on NSCS (west and east of the Pearl River Estuary, WPRE and EPRE, respectively) and ECS shelf in winter were estimated to be 3.8-9.5 × 109, 1.4-2.2 × 109 and 0.7-2.2 ×1010 m3 d-1, respectively. Our results were equivalent to the SGD flux to the entire Mediterranean Sea, and were an order of magnitude greater than fluxes to the South Atlantic Bight. SGD associated nutrient fluxes into WPRE, EPRE and ECS were almost in the same order of magnitude, 0.2-2.4 × 103 mol m-1 d-1 for dissolved inorganic nitrogen, 1.2-9.8 mol m-1 d-1 for soluble reactive phosphorus, and 0.4-3.4 × 103 mol m-1 d-1 for dissolved silicate. Moreover, SGD delivered 1.1-2.8 × 104, 0.6-0.9 × 104, 1.7-5.1 × 104 mol m-1 d-1 dissolved inorganic carbon and 1.1-2.7 × 104, 0.5-0.8 × 104, 1.6-4.8 × 104 mol m-1 d-1 total alkalinity to WPRE, EPRE and ECS, respectively. Shelf-scale SGD is a significant source of nutrients and carbon, and may pose great impacts on regional marine ecosystems.

Wind waves generated by Typhoon Vamei in the southern South China Sea

NASA Astrophysics Data System (ADS)

Mohammed, Aboobacker; Tkalich, Pavel; Krishnakumar, Vinod Kumar; Ponnumony, Vethamony

2013-04-01

Typhoon-generated waves are of interest scientifically for understanding wind-wave interaction physics, as well as operationally for predicting potential hazards. The Typhoon Vamei formed in the southern South China Sea (SCS) was one of the rare typhoon events that occurred near the equator. The typhoon developed on 26 Dec 2001 at 1.4°N in the southern SCS, strengthened quickly, made a landfall along the southeast coast of Malaysia and dissipated over Sumatra on 28 Dec 2001. With the wind speeds were as high as 36 m/s in the southern SCS, this event has significantly affected the atmospheric and oceanic conditions over the region. In the present study, we aim at understanding the wind wave characteristics induced by Vamei along the Sunda Shelf and the southeast coast of Malaysia. Wind velocity vectors over the southern SCS have been simulated for 22-30 Dec 2001 using Weather Research and Forecasting (WRF) model. These winds have been forced in a third generation wave model to compute the wind waves in the affected domain. Simulated significant wave heights reach as high as 7.5m off the southeast coast of Malaysia and 5.8m in the Singapore Strait (SS). Wave propagation from the SCS to the SS is highly noticeable during the typhoon event. Directional distribution and propagation of the Vamei generated waves towards the southeast coast of Malaysia and part of Singapore region have been discussed. Keywords: South China Sea; wind waves; typhoon; numerical modelling; significant wave height.

Estimating the effects of the transboundary transport and local emissions of atmospheric pollutants in South Korea during KORUS-AQ campaign

NASA Astrophysics Data System (ADS)

Lee, S.; Koo, J. H.; Hong, J.; Choi, M.; Kim, J.; Lim, H.; Holben, B. N.; Eck, T. F.; Ahn, J. Y.; Park, J.; Kim, S. K.

2017-12-01

The air quality of South Korea, located in the east of China, is affected by persistent westerlies, showing the relationship to the emission in upwind region. High aerosol concentration in South Korea is also attributed to local emissions. Particularly, the industrial complex and power plants are concentrated in the Chungcheongnam-do (CN), located by the southwest part of Seoul Metropolitan Area (SMA). In this study, we evaluate the contribution of both the transboundary transport of Chinese pollutants and local emissions in the CN to the air quality in South Korea during Korea-US Air Quality (KORUS-AQ) campaign, 1 May to 12 June in 2016. Based on the information of aerosol optical depth (AOD) obtained from ground-based Aerosol Robotic NETwork (AERONET) sunphotometer and surface in-situ Particulate Matter (PM) measurements at 19 stations, high and low aerosol pollution cases are classified first. Then, 2-day back-trajectories are calculated using National Ocean and Atmospheric Administration (NOAA) HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model at each AERONET site to investigate whether transport pattern is different in accordance with the classified cases about aerosol amounts. As a result, we find the distinct pathway of air-mass transport from eastern China; When high AOD is observed at station located in the western coast of South Korea, air masses are directly transported from Shandong peninsular to the Korean peninsula. In contrast, air masses are mostly transported from northwestern or northern China during the period of low AOD conditions. When PM2.5 detected at SMA sites is greater than Korean government criteria (50 micrograms per cubic meter for 24-hour average PM2.5), SMA sites are mostly affected by air mass flows through the CN area. These results indicate that transport pattern can be different vertically and surface aerosol concentration has different transport pattern from the transport pattern related to the variation of

Bird species associated with green ash woodlands in the Slim Buttes, South Dakota

Treesearch

Robert A. Hodorff; Carolyn Hull Sieg

1986-01-01

In western South Dakota, native deciduous woodlands are uncommon, constituting less than 1% of the total land area (Boldt et al. 1978). The Green Ash/Common Chokecherry (Fraxinus pennsylvanica/Prunus virginiana) habitat type is the major deciduous habitat type in northwestern South Dakota (Hansen and Hoffman 1985). This type occurs in depressions,...

New Ceratocystis species from Eucalyptus and Cunninghamia in South China.

PubMed

Liu, FeiFei; Mbenoun, Michael; Barnes, Irene; Roux, Jolanda; Wingfield, Michael J; Li, GuoQing; Li, JieQiong; Chen, ShuaiFei

2015-06-01

During routine surveys for possible fungal pathogens in the rapidly expanding plantations of Eucalyptus and Cunninghamia lanceolata in China, numerous isolates of unknown species in the genus Ceratocystis (Microascales) were obtained from tree wounds. In this study we identified the Ceratocystis isolates from Eucalyptus and Cunninghamia in the GuangDong, GuangXi, FuJian and HaiNan Provinces of South China based on morphology and through comparisons of DNA sequence data for the ITS, partial β-tubulin and TEF-1α gene regions. Morphological and DNA sequence comparisons revealed two previously unknown species residing in the Indo-Pacific Clade. These are described here as Ceratocystis cercfabiensis sp. nov. and Ceratocystis collisensis sp. nov. Isolates of Ceratocystis cercfabiensis showed intragenomic variation in their ITS sequences and four strains were selected for cloning of the ITS gene region. Twelve ITS haplotypes were obtained from 17 clones selected for sequencing, differing in up to seven base positions and representing two separate phylogenetic groups. This is the first evidence of multiple ITS types in isolates of Ceratocystis residing in the Indo-Pacific Clade. Caution should thus be exercised when using the ITS gene region as a barcoding marker for Ceratocystis species in this clade. This study also represents the first record of a species of Ceratocystis from Cunninghamia.

Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

PubMed

Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

2014-01-01

Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

Probabilistic modelling of drought events in China via 2-dimensional joint copula

NASA Astrophysics Data System (ADS)

Ayantobo, Olusola O.; Li, Yi; Song, Songbai; Javed, Tehseen; Yao, Ning

2018-04-01

Probabilistic modelling of drought events is a significant aspect of water resources management and planning. In this study, popularly applied and several relatively new bivariate Archimedean copulas were employed to derive regional and spatial based copula models to appraise drought risk in mainland China over 1961-2013. Drought duration (Dd), severity (Ds), and peak (Dp), as indicated by Standardized Precipitation Evapotranspiration Index (SPEI), were extracted according to the run theory and fitted with suitable marginal distributions. The maximum likelihood estimation (MLE) and curve fitting method (CFM) were used to estimate the copula parameters of nineteen bivariate Archimedean copulas. Drought probabilities and return periods were analysed based on appropriate bivariate copula in sub-region I-VII and entire mainland China. The goodness-of-fit tests as indicated by the CFM showed that copula NN19 in sub-regions III, IV, V, VI and mainland China, NN20 in sub-region I and NN13 in sub-region VII are the best for modeling drought variables. Bivariate drought probability across mainland China is relatively high, and the highest drought probabilities are found mainly in the Northwestern and Southwestern China. Besides, the result also showed that different sub-regions might suffer varying drought risks. The drought risks as observed in Sub-region III, VI and VII, are significantly greater than other sub-regions. Higher probability of droughts of longer durations in the sub-regions also corresponds to shorter return periods with greater drought severity. These results may imply tremendous challenges for the water resources management in different sub-regions, particularly the Northwestern and Southwestern China.

Past 140-year environmental record in the northern South China Sea: evidence from coral skeletal trace metal variations.

PubMed

Song, Yinxian; Yu, Kefu; Zhao, Jianxin; Feng, Yuexing; Shi, Qi; Zhang, Huiling; Ayoko, Godwin A; Frost, Ray L

2014-02-01

About 140-year changes in the trace metals in Porites coral samples from two locations in the northern South China Sea were investigated. Results of PCA analyses suggest that near the coast, terrestrial input impacted behavior of trace metals by 28.4%, impact of Sea Surface Temperature (SST) was 19.0%, contribution of war and infrastructure were 14.4% and 15.6% respectively. But for a location in the open sea, contribution of War and SST reached 33.2% and 16.5%, while activities of infrastructure and guano exploration reached 13.2% and 14.7%. While the spatiotemporal change model of Cu, Cd and Pb in seawater of the north area of South China Sea during 1986-1997 were reconstructed. It was found that in the sea area Cu and Cd contaminations were distributed near the coast while areas around Sanya, Hainan had high Pb levels because of the well-developed tourism related activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Halogenated organic pollutants in marine biota from the Xuande Atoll, South China Sea: Levels, biomagnification and dietary exposure.

PubMed

Sun, Yu-Xin; Hu, Yong-Xia; Zhang, Zai-Wang; Xu, Xiang-Rong; Li, Heng-Xiang; Zuo, Lin-Zi; Zhong, Yi; Sun, Hong; Mai, Bi-Xian

2017-05-15

Six marine biota species were collected from the Xuande Atoll, South China Sea to investigate the bioaccumulation of dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and dechlorane plus (DP). Pike conger (Muraenesox talabonoides) had the highest concentrations of halogenated organic pollutants (HOPs) among the six marine biota species. DDTs were the predominant HOPs, followed by PCBs and PBDEs, with minor contributions of DBDPE and DP. Twenty-one percent of samples had ratios of (DDE+DDD)/ΣDDTs lower than 0.5, implying the presence of fresh DDT inputs in the environment of the Xuande Atoll. The biomagnification factor values for DDTs, PCBs, PBDEs and DP were higher than 1, suggesting biomagnification of these contaminants in the marine food chains. Consumption of seafood from the Xuande Atoll might not subject local residents in the coastal areas of South China to health risks as far as HOPs are concerned. Copyright © 2017 Elsevier Ltd. All rights reserved.

A review of environmental and human exposure to persistent organic pollutants in the Pearl River Delta, South China.

PubMed

Zhang, Kai; Wei, Yan-Li; Zeng, Eddy Y

2013-10-01

Rapid economic growth in South China (including Guangdong Province, Hong Kong, and Macau), particularly within the Pearl River Delta region, has resulted in severe pollution of the natural eco-environment in the last three decades. Large amounts of monitoring data on organic pollution in the Pearl River Delta have been accumulated, which allows us to conduct a fairly comprehensive assessment of the state of the Pearl River Delta and elucidate spatial and temporal patterns of pollution on a regional scale. Of various causes for environmental deterioration, negative impact from persistent organic pollutants (POPs) is a global concern. This review examines the current levels and distribution patterns of several POPs, namely DDT (and its metabolites DDD and DDE), hexachlorocyclohexanes, and polybrominated diphenyl ethers, in various environmental compartments of South China. The general information on environmental occurrence, regional behaviors, ecological effects, and human exposure of these POPs in this region are reviewed. Copyright © 2012 Elsevier B.V. All rights reserved.

New record of Lobophora rosacea (Dictyotales; Phaeophyceae) from the South China Sea

NASA Astrophysics Data System (ADS)

Sun, Zhongmin; Wang, Yongqiang; Yan, Pengcheng; Guo, Hui; Yao, Jianting; Tanaka, Jiro; Kawai, Hiroshi

2017-01-01

Lobophora rosacea C.W. Vieira, Payri et De Clerck is reported from the South China Sea for the first time. Our specimens are very similar to L. rosacea recently described from New Caledonia, not only in morphology but also in rbcL and cox3 gene sequences. The fan-shaped thallus grows erectly, attaching to the substrate by a basal holdfast. The thallus is composed of a single layer of large medullary cells and three to four layers of cortical cells on both sides of the medulla. Mature sporophytes are detected, with sporangium sori scattered on both surfaces of the thallus.

Detrital zircon provenance of the Late Triassic Songpan-Ganzi complex: Sedimentary record of collision of the North and South China blocks

USGS Publications Warehouse

Weislogel, A.L.; Graham, S.A.; Chang, E.Z.; Wooden, J.L.; Gehrels, G.E.; Yang, H.

2006-01-01

Using detrital zircon geochronology, turbidite deposystems fed from distinct sediment sources can be distinguished within the Songpan-Ganzi complex, a collapsed Middle to Late Triassic turbidite basin of central China. A southern Songpan-Ganzi deposystem initially was sourced solely by erosion of the Qinling-Dabie orogen during early Late Triassic time, then by Qinling-Dabie orogen, North China block, and South China block sources during middle to late Late Triassic time. A northern Songpan-Ganzi system was sourced by erosion of the Qinling-Dabie orogen and the North China block throughout its deposition. These separate deposystems were later tectonically amalgamated to form one complex and then uplifted as the eastern Tibet Plateau. ?? 2006 Geological Society of America.

Late paleozoic base and precious metal deposits, East Tianshan, Xinjiang, China: Characteristics and geodynamic setting

USGS Publications Warehouse

Mao, J.; Goldfarb, R.J.; Wang, Y.; Hart, C.J.; Wang, Z.; Yang, J.

2005-01-01

The East Tianshan is a remote Gobi area located in eastern Xinjiang, northwestern China. In the past several years, a number of gold, porphyry copper, and Fe(-Cu) and Cu-Ag-Pb-Zn skarn deposits have been discovered there and are attracting exploration interest. The East Tianshan is located between the Junggar block to the north and early Paleozoic terranes of the Middle Tianshan to the south. It is part of a Hercynian orogen with three distinct E-W-trending tectonic belts: the Devonian-Early Carboniferous Tousuquan-Dananhu island arc on the north and the Carboniferous Aqishan - Yamansu rift basin to the south, which are separated by rocks of the Kanggurtag shear zone. The porphyry deposits, dated at 322 Ma, are related to the late evolutionary stages of a subduction-related oceanic or continental margin arc. In contrast, the skarn, gold, and magmatic Ni-Cu deposits are associated with post-collisional tectonics at ca. 290-270 Ma. These Late Carboniferous - Early Permian deposits are associated with large-scale emplacement and eruption of magmas possibly caused by lithosphere delamination and rifting within the East Tianshan.

A past Haff disease outbreak associated with eating freshwater pomfret in South China

PubMed Central

2013-01-01

Background Haff disease is unexplained rhabdomyolysis caused by consumption of fishery products in the previous 24 h. It was first identified in Europe in 1924 but the condition is extremely rare in China. Here we describe a past outbreak of acute food borne muscle poisoning that occurred in Guangdong Province (South China) in 2009. Methods The first full outbreak of Haff disease reported in Jiangsu Province (East China) in 2010, indicated that the incidence of the disease may be increasing in China. We, therefore first retrospectively reviewed epidemiologic, trace-back, environmental studies, and laboratory analyses, including oral toxicity testing to ascertain risk and chemical analysis to identify toxin(s), from the 2009 Guangdong outbreak. Then we compared data from the 2009 outbreak with data from all other Haff disease outbreaks that were available. Results Clinical symptoms and laboratory findings indicated that the 2009 Guangdong outbreak disease was consistent with rhabdomyolysis. Epidemiologic, trace-back, environmental studies and laboratory analyses implied that the disease was caused by freshwater Pomfrets consumed prior to the onset of symptoms. We also identified common factors between the 2009 Guangdong outbreak and previous Haff disease outbreaks reported around the world, while as with other similar outbreaks, the exact etiological factor(s) of the disease remains unknown. Conclusions The 2009 Guangdong outbreak of ‘muscle poisoning’ was retrospectively identified as an outbreak of Haff disease. This comprised the highest number of cases reported in China thus far. Food borne diseases emerging in this unusual form and the irregular pattern of outbreaks present an ongoing public health risk, highlighting the need for improved surveillance and diagnostic methodology. PMID:23642345

Permian storm current-produced offshore bars from an ancient shelf sequence : Northwestern Karoo basin, republic of South Africa

NASA Astrophysics Data System (ADS)

Smith, A. M.; Zawada, P. K.

The Ecca-Beaufort transition zone from the Karoo Basin comprises upward-coarsening sequences which are interpreted as prograding, storm-produced offshore bars. Eight facies are recognised: (A) dark-grey shale, (B) thinly interbedded siltstone and mudstone, (C) thinly interbedded siltstone and very fine-grained sandstone, (D) blue-grey coarse-grained siltstone, (E) low-angle truncated and flat-laminated sandstone, (F) wave-rippled sandstone, (G) planar cross-bedded sandstone, (H) intraformational clay-pellet conglomerate. Four sub-environments are recognised, these being: (1) the bar crest which comprises proximal tempestites, (2) the bar slope consisting of soft-sediment deformed siltstone, (3) the bar fringe/ margin which is composed of storm layers and offshore siltstones and (4) the interbar/offshore environment comprising siltstone and distal storm layers. These bars formed in response to wave and storm processes and migrated across a muddy shelf environment. The orientation of bars was probably coast-parallel to subparallel with respect to the inferred north-northwest-south-southeast coastline. These proposed, storm-produced bars acted as major depo-centres within the shelf setting of the study area. As shelf sediments are recorded from almost the entire northwestern Karoo Basin it is anticipated that bar formation was an important sedimentary factor in the deposition of the sediments now referred to as the Ecca-Beaufort transition zone.

SCSPOD14, a South China Sea physical oceanographic dataset derived from in situ measurements during 1919-2014.

PubMed

Zeng, Lili; Wang, Dongxiao; Chen, Ju; Wang, Weiqiang; Chen, Rongyu

2016-04-26

In addition to the oceanographic data available for the South China Sea (SCS) from the World Ocean Database (WOD) and Array for Real-time Geostrophic Oceanography (Argo) floats, a suite of observations has been made by the South China Sea Institute of Oceanology (SCSIO) starting from the 1970s. Here, we assemble a SCS Physical Oceanographic Dataset (SCSPOD14) based on 51,392 validated temperature and salinity profiles collected from these three datasets for the period 1919-2014. A gridded dataset of climatological monthly mean temperature, salinity, and mixed and isothermal layer depth derived from an objective analysis of profiles is also presented. Comparisons with the World Ocean Atlas (WOA) and IFREMER/LOS Mixed Layer Depth Climatology confirm the reliability of the new dataset. This unique dataset offers an invaluable baseline perspective on the thermodynamic processes, spatial and temporal variability of water masses, and basin-scale and mesoscale oceanic structures in the SCS. We anticipate improvements and regular updates to this product as more observations become available from existing and future in situ networks.

Nitrogen isotopic composition of nitrate in the South China Sea: A clue to the origin of nitrogen

NASA Astrophysics Data System (ADS)

Yang, Z.; Chen, J.; Chen, M.; Ran, L.; Li, H.; Zhu, Y.; Wang, C.; Ji, Z.; Zhang, J.; Zhang, D.

2016-02-01

Nitrogen isotopic composition of water column nitrate was measured in the South China Sea to clarify the sources of nitrogen. The δ15NNO3 value in deep water (5.4±0.2‰) was higher than the average deep oceanic δ15NNO3 ( 5‰), and a weak δ15NNO3 maximum (5.9±0.2‰) was observed at 500 m depth, matching the salinity minimum. These indicated the intrusion of the North Pacific Water which carried nitrate with a high δ15NNO3 and showed a similar δ15NNO3 distribution profile with the South China Sea. The high N* (1.74±0.23 μmol/L) combined with the low δ15NNO3 (4.7±0.2‰) at 100 m depth indicated that N2 fixation (and possibly Atmospheric Deposition) introduces new N to the surface ocean. The distribution of δ15N values of nitrate, sinking particles and surface sediment suggest that laterally-advected sediments may be a source of nitrogen to the deep ocean.

Rural-urban differentials of premature mortality burden in south-west China.

PubMed

Cai, Le; Chongsuvivatwong, Virasakdi

2006-10-14

Yunnan province is located in south western China and is one of the poorest provinces of the country. This study examines the premature mortality burden from common causes of deaths among an urban region, suburban region and rural region of Kunming, the capital of Yunnan. Years of life lost (YLL) rate per 1,000 and mortality rate per 100,000 were calculated from medical death certificates in 2003 and broken down by cause of death, age and gender among urban, suburban and rural regions. YLL was calculated without age-weighting and discounting rate. Rates were age-adjusted to the combined population of three regions. However, 3% discounting rate and a standard age-weighting function were included in the sensitivity analysis. Non-communicable diseases contributed the most YLL in all three regions. The rural region had about 50% higher premature mortality burden compared to the other two regions. YLL from infectious diseases and perinatal problems was still a major problem in the rural region. Among non-communicable diseases, YLL from stroke was the highest in the urban/suburban regions; COPD followed as the second and was the highest in the rural region. Mortality burden from injuries was however higher in the rural region than the other two regions, especially for men. Self-inflicted injuries were between 2-8 times more serious among women. The use of either mortality rate or YLL gives a similar conclusion regarding the order of priority. Reanalysis with age-weighting and 3% discounting rate gave similar results. Urban south western China has already engaged in epidemiological pattern of developed countries. The rural region is additionally burdened by diseases of poverty and injury on top of the non-communicable diseases.

Biogeographical role of the Kuroshio Current in the amphibious mudskipper Periophthalmus modestus indicated by mitochondrial DNA data.

PubMed

He, Lijun; Mukai, Takahiko; Hou Chu, Ka; Ma, Qiang; Zhang, Jing

2015-10-28

Quaternary climatic cycles have influenced marine organisms' spatial distribution and population dynamics. This study aimed to elucidate the evolutionary influences of contemporary and glacial physical barriers on the population structure, demography and colonization history of the mudskipper (Periophthalmus modestus) based on a mitochondrial gene segment (ND5) from 131 individual fish sampled in the northwestern Pacific Ocean. The current Kuroshio Current and the glacial exposure of the Taiwan Strait appeared to have restricted migration among the South China Sea, coastal East China and Japan. However, genetic homogeneity (Nm>1) also suggested contemporary larval transportation by sea circulation between the East China Sea and the South China Sea or historical dispersal along the glacial exposed shoreline among China, Japan and the Ryukyu Islands. Evolutionary signals of the strengthened East Asian Summer Monsoon in the mid-Pleistocene and regional difference in intertidal primary productions were indicated by a late-Pleistocene population expansion of P. modestus with a higher effective population size in the South China Sea than in the East China Sea. Furthermore, a potential colonization origin from the South China Sea was consistently inferred by different clues, including the populations' coalescence times, the ancestral haplotype distribution, the number of private haplotypes and species/genetic diversity.

Biogeographical role of the Kuroshio Current in the amphibious mudskipper Periophthalmus modestus indicated by mitochondrial DNA data