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Sample records for china sea gorgonian

  1. Diversity and antimicrobial activity of culturable fungi isolated from six species of the South China Sea gorgonians.

    Science.gov (United States)

    Zhang, Xiao-Yong; Bao, Jie; Wang, Guang-Hua; He, Fei; Xu, Xin-Ya; Qi, Shu-Hua

    2012-10-01

    Fungi in gorgonians are now known to cause gorgonian diseases, but little attention has been paid to the nature of fungal communities associated with gorgonians. The diversity of culturable fungi associated with six species of healthy South China Sea gorgonians were investigated using a culture-dependent method followed by analysis of fungal internal transcribed spacer sequences. A total of 121 fungal isolates were recovered and identified using the Basic Local Alignment Search Tool search program. These belonged to 41 fungal species from 20 genera. Of these, 30 species and 12 genera are new reports for gorgonians, and the genera Aspergillus and Penicillium were the most diverse and common in the six gorgonian species. Comparison of the fungal communities in the six gorgonian species, together with results from previous relevant studies, indicated that different gorgonian species and the same gorgonian species living in different geographic locations had different fungal communities. The gorgonian Dichotella gemmacea harbored the most fungal species and isolates, while Echinogorgia aurantiaca had the least fungal diversity. Among the six media used for fungal isolation, potato glucose agar yielded the highest isolates (27 isolates), while glucose peptone starch agar had the best recoverability of fungal species (15 species). The antimicrobial activity of the 121 fungal isolates was tested against three marine bacteria and two marine gorgonian pathogenic fungi. A relatively high proportion (38 %) of fungal isolates displayed distinct antibacterial and antifungal activity, suggesting that the gorgonian-associated fungi may aid their hosts in protection against pathogens. This is the first report comparing the diversity of fungal communities among the South China Sea gorgonians. It contributes to our knowledge of gorgonian-associated fungi and further increases the pool of fungi available for natural bioactive product screening.

  2. Alkaloids and Sesquiterpenes from the South China Sea Gorgonian Echinogorgia pseudossapo

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    Shu-Hua Qi

    2011-11-01

    Full Text Available 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.

  3. Antifouling briarane type diterpenoids from South China Sea gorgonians Dichotella gemmacea

    KAUST Repository

    Sun, Jian Fan

    2013-01-01

    Our continued investigation on the South China Sea gorgonian Dichotella gemmacea led to the isolation of 16 new briarane-type diterpenoids, dichotellides F-U (1-16), along with 18 known analogues (17-34). Their structures were determined by MS, 1D and 2D NMR spectra analyses and by comparison with those reported in literature. The absolute configuration of 15 was confirmed by single-crystal X-ray diffraction data. The antifouling test showed that compounds 3, 4, 6-11, 16, and 23 had potent antifouling activities at nontoxic concentrations with EC50 values of 4.1, 1.82, 6.3, 7.6, 4.6, 1.2, 5.6, 0.79, 2.0, and 0.2 μg/mL, respectively. © 2012 Elsevier Ltd. All rights reserved.

  4. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata.

    Science.gov (United States)

    Huang, Li-Si; He, Fei; Huang, Hui; Zhang, Xiao-Yong; Qi, Shu-Hua

    2012-01-01

    Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6), (-)-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7), (-)-4α,10β-aromadendranediol (8), (+)-4β,10β-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1-5 were conjectured.

  5. Six New Tetraprenylated Alkaloids from the South China Sea Gorgonian Echinogorgia pseudossapo

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    Zhang-Hua Sun

    2014-01-01

    Full Text Available Six new tetraprenylated alkaloids, designated as malonganenones L–Q (1–6, were isolated from the gorgonian Echinogorgia pseudossapo, collected in Daya Bay of Guangdong Province, China. The structures of 1–6 featuring a methyl group at N-3 and a tetraprenyl chain at N-7 in the hypoxanthine core were established by extensive spectroscopic analyses. Compounds 1–6 were tested for their inhibitory activity against the phosphodiesterases (PDEs-4D, 5A, and 9A, and compounds 1 and 6 exhibited moderate inhibitory activity against PDE4D with IC50 values of 8.5 and 20.3 µM, respectively.

  6. Hygrocin C from marine-derived Streptomyces sp. SCSGAA 0027 inhibits biofilm formation in Bacillus amyloliquefaciens SCSGAB0082 isolated from South China Sea gorgonian.

    Science.gov (United States)

    Wang, Jie; Nong, Xu-Hua; Amin, Muhammad; Qi, Shu-Hua

    2018-02-01

    Several ansamycins have been reported to inhibit bacterial biofilm formation and accelerate the eradication of developed biofilms, but little is known about the effect of hygrocin C, an ansamycin, on bacterial biofilm formation. Here, hygrocin C was isolated from the marine-derived Streptomyces sp. SCSGAA 0027 and reported for the first time to be capable of inhibiting the biofilm formation of Staphylococcus aureus and Bacillus amyloliquefaciens SCSGAB0082 with the production of anti-microbial lipopeptides from South China Sea gorgonian Subergorgia suberosa at concentrations of less than minimum inhibitory concentrations. Moreover, hygrocin C also promoted the eradication of developed biofilms, affected the biofilm architecture, and lowered the extracellular polymeric matrix formation, cell motility, and surface hydrophobicity in B. amyloliquefaciens, which was in accordance with the inhibition of biofilm formation. Furthermore, transcriptome analysis revealed that hygrocin C altered the transcripts of several genes associated with bacterial chemotaxis and flagellar, two-component system and the synthesis of arginine and histidine, which are important for bacterial biofilm formation. In conclusion, hygrocin C could be used as a potential biofilm inhibitor against S. aureus and B. amyloliquefaciens. But further genetic investigations are needed to provide more details for elucidation of the molecular mechanisms responsible for the effects of hygrocin C on B. amyloliquefaciens biofilm formation.

  7. Presence of Aspergillus sydowii, a pathogen of gorgonian sea fans in the marine sponge Spongia obscura.

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    Ein-Gil, Neta; Ilan, Micha; Carmeli, Shmuel; Smith, Garriet W; Pawlik, Joseph R; Yarden, Oded

    2009-06-01

    The fungus Aspergillus sydowii is the causative agent of epidemics that affect gorgonian corals (sea fans) and has significantly affected their populations in the Caribbean Sea. We have isolated a strain of A. sydowii from healthy marine sponges (Spongia obscura) collected in Bahamian inshore waters. After its identification on the basis of morphology, molecular markers and chemical profiling followed by pathogenicity tests, we found this strain to be highly similar to a strain isolated from diseased coral, and have shown the capacity of this fungus to persist in sponge environment. Our findings suggest that sponges have the possibility of being reservoirs of a potential marine pathogen.

  8. Seasonal Stability in the Microbiomes of Temperate Gorgonians and the Red Coral Corallium rubrum Across the Mediterranean Sea

    KAUST Repository

    van de Water, Jeroen A. J. M.

    2017-07-05

    Populations of key benthic habitat-forming octocoral species have declined significantly in the Mediterranean Sea due to mass mortality events caused by microbial disease outbreaks linked to high summer seawater temperatures. Recently, we showed that the microbial communities of these octocorals are relatively structured; however, our knowledge on the seasonal dynamics of these microbiomes is still limited. To investigate their seasonal stability, we collected four soft gorgonian species (Eunicella singularis, Eunicella cavolini, Eunicella verrucosa and Leptogorgia sarmentosa) and the precious red coral (Corallium rubrum) from two coastal locations with different terrestrial impact levels in the Mediterranean Sea, and used next-generation amplicon sequencing of the 16S rRNA gene. The microbiomes of all soft gorgonian species were dominated by the same \\'core microbiome\\' bacteria belonging to the Endozoicomonas and the Cellvibrionales clade BD1-7, whereas the red coral microbiome was primarily composed of \\'core\\' Spirochaetes, Oceanospirillales ME2 and Parcubacteria. The associations with these bacterial taxa were relatively consistent over time at each location for each octocoral species. However, differences in microbiome composition and seasonal dynamics were observed between locations and could primarily be attributed to locally variant bacteria. Overall, our data provide further evidence of the intricate symbiotic relationships that exist between Mediterranean octocorals and their associated microbes, which are ancient and highly conserved over both space and time, and suggest regulation of the microbiome composition by the host, depending on local conditions.

  9. The Yellow Gorgonian Eunicella cavolini: Demography and Disturbance Levels across the Mediterranean Sea

    Science.gov (United States)

    Linares, Cristina; Koutsoubas, Drosos; Garrabou, Joaquim

    2015-01-01

    The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (Mediterranean and CE Adriatic, the upper distribution limit was at depths ≤15 m, whereas in the N Aegean most populations were found deeper than 30 m. Population density ranged between 4.46-62 colonies per m2, while mean colony height was 15.6±8.9 SD cm with a maximum of 62 cm. The NW Mediterranean sites were characterized by dense populations dominated by small colonies (30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale. PMID:25942319

  10. South China Sea

    Science.gov (United States)

    Morton, Brian; Blackmore, Graham

    2001-01-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of the three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South

  11. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  12. Gorgonian Alcyonacea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted habitat suitability for several taxa of deep-sea corals. Predictions were modeled using a statistical machine-learning algorithm called...

  13. Fragilisinins A–L, new briarane-type diterpenoids from gorgonian Junceella fragilis

    KAUST Repository

    Lei, Hui

    2014-01-01

    Our continuous study on the South China Sea gorgonian Junceella fragilis led to the isolation of twelve new briarane type diterpenoids, fragilisinins A-L (1-12), along with seven known analogues (13-19), including four naturally produced organoiodides (9-12), they are the first four iodine-containing briarane diterpenoids from this gorgonian species. Their structures were determined by MS, 1D and 2D NMR spectra analyses and by comparison with those reported in the literature. The configuration of 1 was confirmed by single-crystal X-ray diffraction data. The antifouling test showed that compounds 5, 6, 10, 13, and 15 had potent antifouling activities at nontoxic concentrations with EC50 values of 14.0, 12.6, 11.9, 5.6, and 10.0 μM, respectively. © 2014 The Royal Society of Chemistry.

  14. Natural Product Chemistry of Gorgonian Corals of Genus Junceella—Part II

    OpenAIRE

    Mei-Chin Lu; Jimmy Kuo; Jyh-Horng Sheu; Ping-Jyun Sung; Jan-Jung Li; Lee-Shing Fang; Wei-Hsien Wang; Tai-Ting Chou; Yin-Pin Cheng; Ching-Feng Weng; Chia-Hung Lee; Yang-Chang Wu; Jui-Hsin Su

    2011-01-01

    The structures, names, bioactivities, and references of 81 new secondary metabolites obtained from gorgonian corals belonging to the genus Junceella are described in this review. All compounds mentioned in this review were obtained from sea whip gorgonian corals Junceella fragilis and Junceella juncea, collected from the tropical and subtropical Indo-Pacific Ocean.

  15. Ecological shifts in Mediterranean coralligenous assemblages related to gorgonian forest loss.

    Science.gov (United States)

    Ponti, Massimo; Perlini, Rossella Angela; Ventra, Vincenzo; Grech, Daniele; Abbiati, Marco; Cerrano, Carlo

    2014-01-01

    Mediterranean gorgonian forests are threatened by several human activities and are affected by climatic anomalies that have led to mass mortality events in recent decades. The ecological role of these habitats and the possible consequence of their loss are poorly understood. Effects of gorgonians on the recruitment of epibenthic organisms were investigated by manipulating presence of gorgonians on experimental panels at 24 m depth, for Eunicella cavolinii, and at 40 m depth, for Paramuricea clavata, at two sites: Tavolara Island (Tyrrhenian Sea) and Portofino Promontory (Ligurian Sea). After 4 months, the most abundant taxa on the panels were encrusting green algae, erect red algae and crustose coralline algae at 24 m depth and encrusting brown algae and erect red algae at 40 m depth. Assemblages on the panels were significantly affected by the presence of the gorgonians, although effects varied across sites and between gorgonian species. Species diversity and evenness were lower on panels with gorgonian branches. Growth of erect algae and recruitment of serpulid polychaetes were also affected by the presence of the gorgonians, primarily at Tavolara. Crustose coralline algae and erect sponges were more abundant on E. cavolinii panels at 24 m depth, while encrusting bryozoans were more abundant on P. clavata panels at 40 m depth. Effects of gorgonians on recruited assemblages could be due to microscale modification of hydrodynamics and sediment deposition rate, or by a shading effect reducing light intensity. Gorgonians may also intercept settling propagules, compete for food with the filter-feeders and/or for space by producing allelochemicals. Presence of gorgonians mainly limits the growth of erect algae and enhances the abundance of encrusting algae and sessile invertebrates. Therefore, the gorgonian disappearances may cause a shift from assemblages characterised by crustose coralline algae to filamentous algae assemblages, decreasing complexity and resilience

  16. Ecological shifts in Mediterranean coralligenous assemblages related to gorgonian forest loss.

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    Massimo Ponti

    Full Text Available Mediterranean gorgonian forests are threatened by several human activities and are affected by climatic anomalies that have led to mass mortality events in recent decades. The ecological role of these habitats and the possible consequence of their loss are poorly understood. Effects of gorgonians on the recruitment of epibenthic organisms were investigated by manipulating presence of gorgonians on experimental panels at 24 m depth, for Eunicella cavolinii, and at 40 m depth, for Paramuricea clavata, at two sites: Tavolara Island (Tyrrhenian Sea and Portofino Promontory (Ligurian Sea. After 4 months, the most abundant taxa on the panels were encrusting green algae, erect red algae and crustose coralline algae at 24 m depth and encrusting brown algae and erect red algae at 40 m depth. Assemblages on the panels were significantly affected by the presence of the gorgonians, although effects varied across sites and between gorgonian species. Species diversity and evenness were lower on panels with gorgonian branches. Growth of erect algae and recruitment of serpulid polychaetes were also affected by the presence of the gorgonians, primarily at Tavolara. Crustose coralline algae and erect sponges were more abundant on E. cavolinii panels at 24 m depth, while encrusting bryozoans were more abundant on P. clavata panels at 40 m depth. Effects of gorgonians on recruited assemblages could be due to microscale modification of hydrodynamics and sediment deposition rate, or by a shading effect reducing light intensity. Gorgonians may also intercept settling propagules, compete for food with the filter-feeders and/or for space by producing allelochemicals. Presence of gorgonians mainly limits the growth of erect algae and enhances the abundance of encrusting algae and sessile invertebrates. Therefore, the gorgonian disappearances may cause a shift from assemblages characterised by crustose coralline algae to filamentous algae assemblages, decreasing

  17. Is South China Sea the new 'inalienable' part of China?

    OpenAIRE

    Jash, Amrita

    2016-01-01

    China’s growing military posture and unilateral behavior in South China Sea has raised red alarms in international politics, vehemently challenging the existing status quo. What is apparent is that China’s uncompromising attitude in the South China Sea presents China’s obsession over its territorial claims, wherein, South China Sea can be called the ‘new inalienable part’ of China.

  18. Comparative Assessment of Mediterranean Gorgonian-Associated Microbial Communities Reveals Conserved Core and Locally Variant Bacteria

    KAUST Repository

    van de Water, Jeroen A J M

    2016-10-10

    Gorgonians are key habitat-forming species of Mediterranean benthic communities, but their populations have suffered from mass mortality events linked to high summer seawater temperatures and microbial disease. However, our knowledge on the diversity, dynamics and function of gorgonian-associated microbial communities is limited. Here, we analysed the spatial variability of the microbiomes of five sympatric gorgonian species (Eunicella singularis, Eunicella cavolini, Eunicella verrucosa, Leptogorgia sarmentosa and Paramuricea clavata), collected from the Mediterranean Sea over a scale of ∼1100 km, using next-generation amplicon sequencing of the 16S rRNA gene. The microbiomes of all gorgonian species were generally dominated by members of the genus Endozoicomonas, which were at very low abundance in the surrounding seawater. Although the composition of the core microbiome (operational taxonomic units consistently present in a species) was found to be unique for each host species, significant overlap was observed. These spatially consistent associations between gorgonians and their core bacteria suggest intricate symbiotic relationships and regulation of the microbiome composition by the host. At the same time, local variations in microbiome composition were observed. Functional predictive profiling indicated that these differences could be attributed to seawater pollution. Taken together, our data indicate that gorgonian-associated microbiomes are composed of spatially conserved bacteria (core microbiome members) and locally variant members, and that local pollution may influence these local associations, potentially impacting gorgonian health.

  19. Microbial regulation in gorgonian corals.

    Science.gov (United States)

    Hunt, Laura R; Smith, Stephanie M; Downum, Kelsey R; Mydlarz, Laura D

    2012-06-01

    Gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. Since many bacteria use quorum sensing (QS) signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. In the present study, we examined extracts of twelve species of Caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and QS regulatory activity. Ethanol extracts of gorgonians collected from Puerto Rico and the Florida Keys showed a range of both antibacterial and QS activities using a specific Pseudomonas aeruginosa QS reporter, sensitive to long chain AHLs and a short chain N-acylhomoserine lactones (AHL) biosensor, Chromobacterium violaceium. Overall, the gorgonian corals had higher antimicrobial activity against non-marine strains when compared to marine strains. Pseudopterogorgia americana, Pseusopterogorgia acerosa, and Pseudoplexuara flexuosa had the highest QS inhibitory effect. Interestingly, Pseudoplexuara porosa extracts stimulated QS activity with a striking 17-fold increase in signal. The stimulation of QS by P. porosa or other elements of the holobiont may encourage colonization or recruitment of specific microbial species. Overall, these results suggest the presence of novel stimulatory QS, inhibitory QS and bactericidal compounds in gorgonian corals. A better understanding of these compounds may reveal insight into coral-microbial ecology and whether a therapeutic potential exists.

  20. Gunboat Diplomacy in the South China Sea

    Science.gov (United States)

    2012-01-01

    support of Taiwan. 52 China’s aggressive, yet fractured , statements on the South China Sea may be a product of China’s diverse interests in the area. The...when operational, is meant to challenge the U.S. F-22 Raptor . As the DoD notes in its 2011 annual report on China, “In all areas, China is

  1. Microbial Regulation in Gorgonian Corals

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    Laura D. Mydlarz

    2012-06-01

    Full Text Available Gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. Since many bacteria use quorum sensing (QS signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. In the present study, we examined extracts of twelve species of Caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and QS regulatory activity. Ethanol extracts of gorgonians collected from Puerto Rico and the Florida Keys showed a range of both antibacterial and QS activities using a specific Pseudomonas aeruginosa QS reporter, sensitive to long chain AHLs and a short chain N-acylhomoserine lactones (AHL biosensor, Chromobacterium violaceium. Overall, the gorgonian corals had higher antimicrobial activity against non-marine strains when compared to marine strains. Pseudopterogorgia americana, Pseusopterogorgia acerosa, and Pseudoplexuara flexuosa had the highest QS inhibitory effect. Interestingly, Pseudoplexuara porosa extracts stimulated QS activity with a striking 17-fold increase in signal. The stimulation of QS by P. porosa or other elements of the holobiont may encourage colonization or recruitment of specific microbial species. Overall, these results suggest the presence of novel stimulatory QS, inhibitory QS and bactericidal compounds in gorgonian corals. A better understanding of these compounds may reveal insight into coral-microbial ecology and whether a therapeutic potential exists.

  2. Deep-sea geohazards in the South China Sea

    Science.gov (United States)

    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.

  3. Non-Gorgonian Alcyonacea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted habitat suitability for several taxa of deep-sea corals. Predictions were modeled using a statistical machine-learning algorithm called...

  4. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  5. Potent Antifouling Resorcylic Acid Lactones from the Gorgonian-Derived Fungus Cochliobolus lunatus

    KAUST Repository

    Shao, Chang Lun

    2011-04-25

    Three new 14-membered resorcylic acid lactones, two with a rare natural acetonide group and one with a 5-chloro-substituted lactone, named cochliomycins A-C (1-3), together with four known analogues, zeaenol (4), LL-Z1640-1 (5), LL-Z1640-2 (6), and paecilomycin F (7), were isolated from the culture broth of Cochliobolus lunatus, a fungus obtained from the gorgonian Dichotella gemmacea collected in the South China Sea. Their structures and the relative configurations of 1-3 were elucidated using comprehensive spectroscopic methods including NOESY spectra and chemical conversions. A transetherification reaction was also observed in which cochliomycin B (2) in a solution of CDCl3 slowly rearranged to give cochliomycin A (1) at room temperature. These resorcylic acid lactones were evaluated against the larval settlement of barnacle Balanus amphitrite, and antifouling activity was detected for the first time for this class of metabolites. The antibacterial and cytotoxic activities of these compounds were also examined. © 2011 The American Chemical Society and American Society of Pharmacognosy.

  6. Effects of wave energy, topographic relief and sediment transport on the distribution of shallow-water gorgonians of Puerto Rico

    Science.gov (United States)

    Yoshioka, Paul M.; Yoshioka, Beverly Buchanan

    1989-12-01

    Environmental factors controlling the distribution of shallow-water gorgonians of Puerto Rico were inferred from a Reciprocal Averaging ordination analysis. The data set included several samples taken before and after the passage of Hurricane David and the mass mortality of the sea urchin Diadema antillarum. We could infer only a single environmental gradient associated with the distribution of gorgonians. Stations at opposite extremes of this gradient were characterized by combinations of high wave action with low topographic relief, or low wave action with high topographic relief. This gradient was also associated with sediment transport across the bottom (bedload). A detailed examination of ordination results in relation to Hurricane David and the Diadema mortality indicated that sediment transport, rather than water movement and topographic relief, is more directly related to the distribution of shallow-water gorgonians.

  7. Limited Genetic Connectivity between Gorgonian Morphotypes along a Depth Gradient.

    Directory of Open Access Journals (Sweden)

    Federica Costantini

    Full Text Available Gorgonian species show a high morphological variability in relation to the environment in which they live. In coastal areas, parameters such as temperature, light, currents, and food availability vary significantly with depth, potentially affecting morphology of the colonies and the structure of the populations, as well as their connectivity patterns. In tropical seas, the existence of connectivity between shallow and deep populations supported the hypothesis that the deep coral reefs could potentially act as (reproductive refugia fostering re-colonization of shallow areas after mortality events. Moreover, this hypothesis is not so clear accepted in temperate seas. Eunicella singularis is one of the most common gorgonian species in Northwestern Mediterranean Sea, playing an important role as ecosystem engineer by providing biomass and complexity to the coralligenous habitats. It has a wide bathymetric distribution ranging from about 10 m to 100 m. Two depth-related morphotypes have been identified, differing in colony morphology, sclerite size and shape, and occurrence of symbiotic algae, but not in mitochondrial DNA haplotypes. In the present study the genetic structure of E. singularis populations along a horizontal and bathymetric gradient was assessed using microsatellites and ITS1 sequences. Restricted gene flow was found at 30-40 m depth between the two Eunicella morphotypes. Conversely, no genetic structuring has been found among shallow water populations within a spatial scale of ten kilometers. The break in gene flow between shallow and deep populations contributes to explain the morphological variability observed at different depths. Moreover, the limited vertical connectivity hinted that the refugia hypothesis does not apply to E. singularis. Re-colonization of shallow water populations, occasionally affected by mass mortality events, should then be mainly fueled by larvae from other shallow water populations.

  8. Observational analysis of air-sea fluxes and sea water temperature offshore South China Sea

    Science.gov (United States)

    Bi, X.; Huang, J.; Gao, Z.; Liu, Y.

    2017-12-01

    This paper investigates the air-sea fluxes (momentum flux, sensible heat flux and latent heat flux) from eddy covariance method based on data collected at an offshore observation tower in the South China Sea from January 2009 to December 2016 and sea water temperature (SWT) on six different levels based on data collected from November 2011 to June 2013. The depth of water at the tower over the sea averages about 15 m. This study presents the in-situ measurements of continuous air-sea fluxes and SWT at different depths. Seasonal and diurnal variations in air-sea fluxes and SWT on different depths are examined. Results show that air-sea fluxes and all SWT changed seasonally; sea-land breeze circulation appears all the year round. Unlike winters where SWT on different depths are fairly consistent, the difference between sea surface temperature (SST) and sea temperature at 10 m water depth fluctuates dramatically and the maximum value reaches 7 °C during summer.

  9. Distribution characteristics of marine litter on the sea bed of the East China Sea and the South Sea of Korea

    Science.gov (United States)

    Lee, Dae-In; Cho, Hyeon-Seo; Jeong, Sun-Beom

    2006-10-01

    The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996-2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km -2, and low in the East China Sea, with densities of 30.6 kg km -2. Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42-72% and 37-62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

  10. Brazilian gorgonians: a source of odoriferous compounds?

    Directory of Open Access Journals (Sweden)

    Silvia Siag Oigman

    Full Text Available Abstract The gorgonian Phyllogorgia dilatata Esper is an octocoral known to be source of biologically active terpenes. In this study, odoriferous compounds present in P. dilatata tissues were investigated, due to their exotic olfactory notes. The search of volatile compounds was performed in a dichloromethane/methanol extract submitted to a silica gel vacuum chromatography and HPLC, yielding the isomers (Z,E and (E,E-germacrones, identified by GC/MS, 1 and 2D NMR. The stereochemistry of (E,E-germacrone, as well as its preferred conformation, was confirmed by NOESY. Sensory analysis of the two isomers revealed a fragrant, citrus, woody and weak marine odor, similar to the odor of the natural gorgonian, and (E,E-germacrone has a three times more intense aroma than the (Z,E isomer.

  11. Potential of sea level rise impact on South China Sea: a preliminary ...

    African Journals Online (AJOL)

    The effect of the sea level rise was involved the existence of sea water intrusion and coastal erosion phenomenon in the coastal of Terengganu. This study aim to determine fluctuation of high and low tides of the South China Sea in their relation to water quality value of Marang and Paka Rivers as well as from wells ...

  12. Subseasonal variability during the South China Sea summer monsoon onset

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Renguang [Center for Ocean-Land-Atmosphere Studies, 4041 Powder Mill Road, Suite 302, Calverton, MD (United States)

    2010-04-15

    Analysis of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) data for the period 1998-2007 reveals large subseasonal fluctuations in sea surface temperature (SST) of the South China Sea during the summer monsoon onset. These subseasonal SST changes are closely related to surface heat flux anomalies induced by surface wind and cloud changes in association with the summer monsoon onset. The SST changes feed back on the atmosphere by modifying the atmospheric instability. The results suggest that the South China Sea summer monsoon onset involves ocean-atmosphere coupling on subseasonal timescales. While the SST response to surface heat flux changes is quick and dramatic, the time lag between the SST anomalies and the atmospheric convection response varies largely from year to year. The spatial-temporal evolution of subseasonal anomalies indicates that the subseasonal variability affecting the South China Sea summer monsoon onset starts over the equatorial western Pacific, propagates northward to the Philippine Sea, and then moves westward to the South China Sea. The propagation of these subseasonal anomalies is related to the ocean-atmosphere interaction, involving the wind-evaporation and cloud-radiation effects on SST as well as SST impacts on lower-level convergence over the equatorial western Pacific and atmospheric instability over the Philippine Sea and the South China Sea. (orig.)

  13. The South China Sea Thermohaline Structure and Circulation

    National Research Council Canada - National Science Library

    Chu, Peter C; Ma, Binbing; Chen, Yuchun

    2002-01-01

    ...), consisting of 116,019 temperature and 9,617 salinity profiles, during 1968-1984 to investigate the temporal and spatial variabilities of South China Sea thermohaline structures and circulation...

  14. South China Sea disputes: ASEAN’s Role in Addressing Disputes with China

    Science.gov (United States)

    2013-12-13

    25 Constructivism ...........................................................................................................27 ASEAN, China and...realism, liberalism and constructivism and their relevance to policies of ASEAN claimants and ASEAN as the regional organization will help in...Realism, Liberalism, and Constructivism observers can view China, ASEAN, and the South China Sea claimants’ policies and approaches from a

  15. Bacteria of the genus Endozoicomonas dominate the microbiome of the Mediterranean gorgonian coral Eunicella cavolini

    KAUST Repository

    Bayer, T

    2013-04-08

    Forming dense beds that provide the structural basis of a distinct ecosystem, the gorgonian Eunicella cavolini (Octocorallia) is an important species in the Mediterranean Sea. Despite the importance and prevalence of this temperate gorgonian, little is known about its microbial assemblage, although bacteria are well known to be important to hard and soft coral functioning. Here, we used massively parallel pyrosequencing of 16S rRNA genes to determine the composition and relative abundances of bacteria associated with E. cavolini collected from different depths at a site on the French Mediterranean coast. We found that whereas the bacterial assemblages of E. cavolini were distinct and less diverse than those of the surrounding water column, the water depth did not affect the bacterial assemblages of this gorgonian. Our data show that E. cavolini?s microbiome contains only a few shared species and that it is highly dominated by bacteria from the genus Endozoicomonas, a Gammaproteobacteria that is frequently found to associate with marine invertebrates.

  16. POWER AND CULTURE IN THE SOUTH CHINA SEA

    Science.gov (United States)

    2016-02-16

    DISTRIBUTION A. Approved for public release: distribution unlimited. ii DISCLAIMER The views expressed in this academic research paper are...and maritime domain between China and the Philippines, Vietnam, Malaysia , and the Republic of China. The United States must make difficult foreign...policy- makers in analyzing China’s behavior in the South China Sea. This is not a matter of armchair academic theorizing – rather, the chosen

  17. Sea Reclamation Status of Countries around the South China Sea from 1975 to 2010

    Directory of Open Access Journals (Sweden)

    Junjue Zhang

    2017-05-01

    Full Text Available As a way of turning sea into land for living space for humans, the actions of sea reclamation bring about significant benefits. Nevertheless, it is also an under-recognized threat to the environment and the marine ecosystem. Based on images in two periods, sea reclamation information of countries around the South China Sea was extracted from 1975 to 2010. The spatial state and driven forces of sea reclamation are then discussed. Results show that the overall strength of sea reclamation in the South China Sea was great. New reclaimed land added up to 3264 km2. Sea reclamation for fish farming was the main reclamation type and widely distributed in the whole area, especially on the coast from the Pearl River Delta to the Red River Delta, and the coast of Ca Mau Peninsula. Sea reclamation in China and Vietnam was rather significant, which occupies 80.6% of the total reclamation area. Singapore had the highest level of sea reclamation. New reclaimed land for fish farming holds a key role in China, Vietnam, and Indonesia, while new reclaimed land for construction and docks dominated in Malaysia, Singapore, and Brunei. Areas and use-type compositions of new reclaimed land in countries varied greatly due to the differences of economic factors, policy inclination, and landscapes in the respective countries.

  18. Impacts of Typhoon Megi (2010) on the South China Sea

    Science.gov (United States)

    2014-06-01

    for Environmental Science, Cambridge, Maryland, USA, 3Department of Atmospheric Sciences, National Taiwan University, Taipei , Taiwan Abstract In October...2010, typhoon Megi induced a profound cold wake of size 800 km by 500 km with sea surface temperature cooling of 8C in the South China Sea (SCS...Sea (SCS) around 1500 UTC 18 October. It weakened to category-3 over land but regained back to the category-4 intensity after entering the SCS. An

  19. Increasing eutrophication in the coastal seas of China from 1970 to 2050

    NARCIS (Netherlands)

    Strokal, M.; Yang, H.; Zhang, Y.; Kroeze, C.; Li, L.; Luan, S.; Wang, H.; Yang, S.

    2014-01-01

    We analyzed the potential for eutrophication in major seas around China: the Bohai Gulf, Yellow Sea and South China Sea. We model the riverine inputs of nitrogen (N), phosphorus (P) and silica (Si) to coastal seas from 1970 to 2050. Between 1970 and 2000 dissolved N and P inputs to the three seas

  20. Distinguishing Terrestrial Organic Carbon in Marginal Sediments of East China Sea and Northern South China Sea

    Science.gov (United States)

    Kandasamy, Selvaraj; Lin, Baozhi; Wang, Huawei; Liu, Qianqian; Liu, Zhifei; Lou, Jiann-Yuh; Chen, Chen-Tung Arthur; Mayer, Lawrence M.

    2016-04-01

    Knowledge about the sources, transport pathways and behavior of terrestrial organic carbon in continental margins adjoining to large rivers has improved in recent decades, but uncertainties and complications still exist with human-influenced coastal regions in densely populated wet tropics and subtropics. In these regions, the monsoon and other episodic weather events exert strong climatic control on mineral and particulate organic matter delivery to the marginal seas. Here we investigate elemental (TOC, TN and bromine-Br) and stable carbon isotopic (δ13C) compositions of organic matter (OM) in surface sediments and short cores collected from active (SW Taiwan) and passive margin (East China Sea) settings to understand the sources of OM that buried in these settings. We used sedimentary bromine to total organic carbon (Br/TOC) ratios to apportion terrigenous from marine organic matter, and find that Br/TOC may serve as an additional, reliable proxy for sedimentary provenance in both settings. Variations in Br/TOC are consistent with other provenance indicators in responding to short-lived terrigenous inputs. Because diagenetic alteration of Br is insignificant on shorter time scales, applying Br/TOC ratios as a proxy to identify organic matter source along with carbon isotope mixing models may provide additional constraints on the quantity and transformation of terrigenous organics in continental margins. We apply this combination of approaches to land-derived organic matter in different depositional environments of East Asian marginal seas.

  1. Status of marine biodiversity of the China seas.

    Science.gov (United States)

    Liu, J Y

    2013-01-01

    China's seas cover nearly 5 million square kilometers extending from the tropical to the temperate climate zones and bordering on 32,000 km of coastline, including islands. Comprehensive systematic study of the marine biodiversity within this region began in the early 1950s with the establishment of the Qingdao Marine Biological Laboratory of the Chinese Academy of Sciences. Since that time scientists have carried out intensive multidisciplinary research on marine life in the China seas and have recorded 22,629 species belonging to 46 phyla. The marine flora and fauna of the China seas are characterized by high biodiversity, including tropical and subtropical elements of the Indo-West Pacific warm-water fauna in the South and East China seas, and temperate elements of North Pacific temperate fauna mainly in the Yellow Sea. The southern South China Sea fauna is characterized by typical tropical elements paralleled with the Philippine-New Guinea-Indonesia Coral triangle typical tropical faunal center. This paper summarizes advances in studies of marine biodiversity in China's seas and discusses current research mainly on characteristics and changes in marine biodiversity, including the monitoring, assessment, and conservation of endangered species and particularly the strengthening of effective management. Studies of (1) a tidal flat in a semi-enclosed embayment, (2) the impact of global climate change on a cold-water ecosystem, (3) coral reefs of Hainan Island and Xisha-Nansha atolls, (4) mangrove forests of the South China Sea, (5) a threatened seagrass field, and (6) an example of stock enhancement practices of the Chinese shrimp fishery are briefly introduced. Besides the overexploitation of living resources (more than 12.4 million tons yielded in 2007), the major threat to the biodiversity of the China seas is environmental deterioration (pollution, coastal construction), particularly in the brackish waters of estuarine environments, which are characterized by

  2. Status of marine biodiversity of the China seas.

    Directory of Open Access Journals (Sweden)

    J Y Liu

    Full Text Available China's seas cover nearly 5 million square kilometers extending from the tropical to the temperate climate zones and bordering on 32,000 km of coastline, including islands. Comprehensive systematic study of the marine biodiversity within this region began in the early 1950s with the establishment of the Qingdao Marine Biological Laboratory of the Chinese Academy of Sciences. Since that time scientists have carried out intensive multidisciplinary research on marine life in the China seas and have recorded 22,629 species belonging to 46 phyla. The marine flora and fauna of the China seas are characterized by high biodiversity, including tropical and subtropical elements of the Indo-West Pacific warm-water fauna in the South and East China seas, and temperate elements of North Pacific temperate fauna mainly in the Yellow Sea. The southern South China Sea fauna is characterized by typical tropical elements paralleled with the Philippine-New Guinea-Indonesia Coral triangle typical tropical faunal center. This paper summarizes advances in studies of marine biodiversity in China's seas and discusses current research mainly on characteristics and changes in marine biodiversity, including the monitoring, assessment, and conservation of endangered species and particularly the strengthening of effective management. Studies of (1 a tidal flat in a semi-enclosed embayment, (2 the impact of global climate change on a cold-water ecosystem, (3 coral reefs of Hainan Island and Xisha-Nansha atolls, (4 mangrove forests of the South China Sea, (5 a threatened seagrass field, and (6 an example of stock enhancement practices of the Chinese shrimp fishery are briefly introduced. Besides the overexploitation of living resources (more than 12.4 million tons yielded in 2007, the major threat to the biodiversity of the China seas is environmental deterioration (pollution, coastal construction, particularly in the brackish waters of estuarine environments, which are

  3. Zooplankton community structure in the Yellow Sea and East China Sea in autumn

    Directory of Open Access Journals (Sweden)

    Hongju Chen

    2015-12-01

    Full Text Available Abstract Study on zooplankton spatial distribution is essential for understanding food web dynamics in marine ecosystems and fishery management. Here we elucidated the composition and distribution of large mesozooplankton on the continental shelf of the Yellow Sea and East China Sea, and explored the zooplankton community structure in these water masses. Sixty vertical hauls (bottom or 200 m in deep water to surface using a ring net (diameter 0.8 m, 505-μm mesh were exploited in November 2007. The biogeographic patterns of zooplankton communities were investigated using multivariate analysis methods; copepod biodiversity was analyzed using univariate indices. Copepods and protozoans were dominate in the communities. Based on the species composition, we divided the study areas into six station groups. Significant differences in zooplankton assemblages were detected between the Yellow Sea and East China Sea. Species richness was higher in East China Sea groups than those in Yellow Sea, whereas taxonomic distinctness was higher in Yellow Sea than in East China Sea. There was a clear relationship between the species composition and water mass group.

  4. Navigating the Security Dilemma: China, Vietnam, and the South China Sea

    Directory of Open Access Journals (Sweden)

    Jason J. Blazevic

    2012-01-01

    Full Text Available Competition and conflict in the South China Sea involves many nations due to its resources and vital sea lanes. However, it is China which increasingly serves as a common denominator of intensifying anxiety for its South China Sea maritime neighbours due to the aggressive scope of its claims to the sea and its islands. Among those states, Vietnam is most affected as it is first in the path of Chinese ambitions – ambitions which authorities fear would give China significant tactical military and economic advantage. For China, there are similar fears over threats to the sea lanes and sea bed resources. Leaders of both states also perceive their diplomatic and martial actions in the sea in historical terms as well. However, enforcement actions taken by either state may lead to a worsening security dilemma in which reactive security strategies could dangerously destabilise relations. This article discusses the motivations and strategies of both states as well as the consequences of such and applies realism, its tenets of defensive and offensive realism, and neoliberalism to examine their security concerns and perceptions. The article further proposes that the most valuable insights can be provided by defensive realism and neoliberalism, which together can encourage security, cooperation and conciliation in order to best promote the improvement of relations.

  5. The South China Sea Deep: A Research Project on Life History of Marginal Sea

    Science.gov (United States)

    Wang, P.

    2011-12-01

    A major research project has been launched in China to investigate evolution and various processes in the deep-water part a of the South China Sea. The "South China Sea Deep" project (2011-2018) is supported by the NSF of China with a total budget no less than ~23 US Dollar (150 Million Chinese yuan), and covers a broad spectrum of scientific topics. Advanced geophysical and geochemical tools will be applied to re-estimate the age of its oceanic crust, to verify the existence of the "Hainan Mantle Plume", and to explore the origin of volcanic chains in the deep basin. Sedimentary archives, both off-shore and on-shore, will be analyzed to reconstruct the history of sediment response to the basin evolution, with focus on changes of deep-water circulation driven by tectonic deformation of the basin. Deep-water observations will be organized to examine near-bottom sediment transport, methane seepages, and microbial distribution and ecology above and below sea-floor. With a combination of tectonic-magmatic, sedimentologic-paleoceanographic, and microbiological-geochemical approaches, the project is expected to reveal the life history of the South China Sea, the largest low-latitude marginal sea in the modern world. Recent progress of the project will be presented, and perspectives of international cooperation will be discussed.

  6. Effect of Ocean Interannual Variability on Acoustic Propagation in the Philippine Sea and South China Sea

    Science.gov (United States)

    2017-06-01

    Philippine Sea and South China Sea. Recently, a Synoptic Monthly Gridded World Ocean Database (SMG-WOD) with horizontal resolution of 1o world - wide ...Gridded World Ocean Database (SMG- WOD) data from January 1960 to December 2014, and an open source acoustic model (BELLHOP). The multi-year averaged...partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN METEOROLOGY AND PHYSICAL OCEANOGRAPHY from the NAVAL

  7. Low clonal propagation in Atlantic and Mediterranean populations of the red gorgonian Paramuricea clavata (Octocorallia

    Directory of Open Access Journals (Sweden)

    Joanna Pilczynska

    2017-03-01

    Full Text Available Clonal propagation is a common feature of benthic marine organisms. In the present study, we investigated the contribution of clonal reproduction in the red gorgonian Paramuricea clavata. Mediterranean populations of P. clavata were severely affected by mass mortality events caused by increased water temperature in 1999 and 2003. The populations are characterized by slow growth and episodic recruitment, but after the observed mortalities, an unexpectedly high recovery rate was observed in the severely affected populations from the Ligurian Sea, NW Mediterranean. Ten years after the last mortality event, we investigated the contribution of clonal propagation in populations from the Ligurian Sea, where some populations were highly affected by mass mortality events, and from the Atlantic, where mortality was never observed. All individuals were genotyped for nine microsatellite loci. The contribution of clonal reproduction varied from 0% to 13% and did not differ significantly between affected and unaffected populations. We confirm by using genetic markers that clonal propagation in P. clavata is not common, and that the contribution of clones is too low to play an important role in red gorgonian reproduction and cannot contribute to population recovery at sites that have been affected by mass mortality events.

  8. Distribution of Bottom Trawling Effort in the Yellow Sea and East China Sea.

    Directory of Open Access Journals (Sweden)

    Shengmao Zhang

    Full Text Available Bottom trawling is one of the most efficient fishing activities, but serious and persistent ecological issues have been observed by fishers, scientists and fishery managers. Although China has applied the Beidou fishing vessel position monitoring system (VMS to manage trawlers since 2006, little is known regarding the impacts of trawling on the sea bottom environments. In this study, continuous VMS data of the 1403 single-rig otter trawlers registered in the Xiangshan Port, 3.9% of the total trawlers in China, were used to map the trawling effort in 2013. We used the accumulated distance (AD, accumulated power distance (APD, and trawling intensity as indexes to express the trawling efforts in the Yellow Sea (YS and East China Sea (ECS. Our results show that all three indexes had similar patterns in the YS and ECS, and indicated a higher fishing effort of fishing grounds that were near the port. On average, the seabed was trawled 0.73 times in 2013 over the entire fishing region, and 51.38% of the total fishing grounds were with no fishing activities. Because of VMS data from only a small proportion of Chinese trawlers was calculated fishing intensity, more VMS data is required to illustrate the overall trawling effort in China seas. Our results enable fishery managers to identify the distribution of bottom trawling activities in the YS and ECS, and hence to make effective fishery policy.

  9. Deep Sea Researches in the South China Sea: Past, Present and Future

    Science.gov (United States)

    Wang, P.

    2016-12-01

    The South China Sea(SCS) has increasingly become a global focus in ocean research. Over the last two decades, at least 17 international cruises including ocean drillings were conducted in the SCS, and many new international expeditions will take place in the years to come. International collaboration is a tradition of deep sea researches in the SCS. After the pioneering works in the 1970s and 1980s, based on research vessels from US, Germany, USSR and China, more systematical studies of paleoceanography and geophysics/tectonics took place in the 1990s and 2000s, supported largely by research vessels from Germany, France and China. Since the launch of the "SCS Deep" Program in 2011, the deep sea researches in the SCS reached unprecedented level, again with active international collaboration. A suite of state-of-art techniques have been adopted to dissect this typical marginal sea in its history of evolution and its modern processes. Of particular importance was the IODP Leg 349 in 2014 aimed at dating the process of seafloor spreading. Currently, many new research activities in the deep water SCS are underway or in preparation. Four months of IODP drilling is scheduled for early 2017 to address the mechanism of continental breakup at its northern margin. A multi-national team is pushing to drill the Sunda shelf for the Plio-Pleistocene sea-level history. Located between the largest ocean and the largest continent of the world, the SCS provides an ideal natural laboratory for the international community to investigate marine processes and sea-land interactions. A new initiative of international collaboration in the SCS is called for to further enhance the deep-sea researches there. This new major research program should lead to a series of breakthroughs in our understanding not only of the evolution of a marginal basin, but also of many basic processes of sea-land interactions.

  10. Airborne Sea of Dust over China

    Science.gov (United States)

    2002-01-01

    TDust covered northern China in the last week of March during some of the worst dust storms to hit the region in a decade. The dust obscuring China's Inner Mongolian and Shanxi Provinces on March 24, 2002, is compared with a relatively clear day (October 31, 2001) in these images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera aboard NASA's Terra satellite. Each image represents an area of about 380 by 630 kilometers (236 by 391 miles). In the image from late March, shown on the right, wave patterns in the yellowish cloud liken the storm to an airborne ocean of dust. The veil of particulates obscures features on the surface north of the Yellow River (visible in the lower left). The area shown lies near the edge of the Gobi desert, a few hundred kilometers, or miles, west of Beijing. Dust originates from the desert and travels east across northern China toward the Pacific Ocean. For especially severe storms, fine particles can travel as far as North America. The Multi-angle Imaging SpectroRadiometer, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is one of five Earth-observing instruments aboard the Terra satellite, launched in December 1999. The instrument acquires images of Earth at nine angles simultaneously, using nine separate cameras pointed forward, downward and backward along its flight path. The change in reflection at different view angles affords the means to distinguish different types of atmospheric particles, cloud forms and land surface covers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team

  11. Balance of Risk in the South China Sea

    Science.gov (United States)

    2015-06-01

    Kalayaan Island Group.35 The Malaysian claim was a reaction to Marco’s presidential decree and occupation of KIG, which it considered a part of its own...craft LSG Leading Small Group MFA Ministry of Foreign Affairs MOA Ministry of Agriculture MPS Ministry of Public Security MSA Maritime Safety ...claim.36 The Malaysian claim 30 Buszynski, “South China Sea Maritime Dispute,” 6; Erik Franckx and

  12. Polychaete species (Annelida) described from the Philippine and China Seas.

    Science.gov (United States)

    Salazar-Vallejo, Sergio I; Carrera-Parra, Luis F; Muir, Alexander I; De León-González, Jesús Angel; Piotrowski, Christina; Sato, Masanori

    2014-07-30

    The South China and Philippine Seas are among the most diverse regions in the Western Pacific. Although there are several local polychaete checklists available, there is none comprising the whole of this region. Presented herein is a comprehensive list of the original names of all polychaete species described from the region. The list contains 1037 species, 345 genera and 60 families; the type locality, type depository, and information regarding synonymy are presented for each species. 

  13. Approaches Toward Deterring Chinese Aggression in the South China Sea

    Science.gov (United States)

    2017-06-09

    Fiery Cross Reef may have been chosen by China as its keystone for its push into the SCS mostly because of the depths of its surrounding waters...thoroughfares from East to West and vice-versa. Dominating these seas is a keystone to power projection into the Eurasian continent and areas beyond. This...endangered species . The U.S. would have an opportunity to insert itself in this process as a neutral party in order to help in establishing measures to

  14. Genetic Diversity and Local Connectivity in the Mediterranean Red Gorgonian Coral after Mass Mortality Events.

    Science.gov (United States)

    Pilczynska, Joanna; Cocito, Silvia; Boavida, Joana; Serrão, Ester; Queiroga, Henrique

    2016-01-01

    Estimating the patterns of connectivity in marine taxa with planktonic dispersive stages is a challenging but crucial task because of its conservation implications. The red gorgonian Paramuricea clavata is a habitat forming species, characterized by short larval dispersal and high reproductive output, but low recruitment. In the recent past, the species was impacted by mass mortality events caused by increased water temperatures in summer. In the present study, we used 9 microsatellites to investigate the genetic structure and connectivity in the highly threatened populations from the Ligurian Sea (NW Mediterranean). No evidence for a recent bottleneck neither decreased genetic diversity in sites impacted by mass mortality events were found. Significant IBD pattern and high global FST confirmed low larval dispersal capability in the red gorgonian. The maximum dispersal distance was estimated at 20-60 km. Larval exchange between sites separated by hundreds of meters and between different depths was detected at each site, supporting the hypothesis that deeper subpopulations unaffected by surface warming peaks may provide larvae for shallower ones, enabling recovery after climatically induced mortality events.

  15. Investigating Bermuda's pollution history through stable isotope analyses of modern and museum-held gorgonian corals.

    Science.gov (United States)

    Baker, David M; Murdoch, Thaddeus J T; Conti-Jerpe, Inga; Fogel, Marilyn

    2017-01-15

    For centuries, Bermuda has been challenged with wastewater management for the protection of human and environmental health. By quantifying the δ 15 N of the common sea fan Gorgonia ventalina sampled from 30 sites throughout Bermuda we show that sewage-derived nitrogen is detectable on nearshore coral reefs and declines across the lagoon to the outer rim. We also sampled gorgonians from two museum collections representing a 50y time-series (1958-2008). These samples revealed an increase in δ 15 N of >4.0‰ until the mid-1970s, after which δ 15 N values slowly declined by ~2.0‰. A δ 15 N chronology from a gorgonian skeleton exhibited a similar decline over the last 30-40years of approximately 0.6‰. We conclude that policies have been effective in reducing sewage impacts to Bermudian reefs. However, significant sources of sewage pollution persist and are likely have a strong impact on harbor and nearshore coral communities and human health. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Heavy metals in sea cucumber juveniles from coastal areas of Bohai and Yellow seas, north China.

    Science.gov (United States)

    Jiang, Haifeng; Tang, Shizhan; Qin, Dongli; Chen, Zhongxiang; Wang, Jinlong; Bai, Shuyan; Mou, Zhenbo

    2015-05-01

    The study was undertaken to assess the contents of heavy metals (Cu, Zn, Cr, Pb, Cd, As and Hg) in sea cucumber (Apostichopus japonicus) juveniles from coastal areas of Bohai and Yellow seas in northern China. Sea cucumber juveniles were collected from twenty commercial hatcheries distributed in five coastal cities. The mean concentrations obtained for heavy metals in mg/kg were as follows: Cu (0.179), Zn (2.634), Cr (0.108), Pb (0.065), Cd (0.161), As (0.372), Hg (0.034). All the mean concentrations were below the maximum residual limits set by Chinese legislation, but As in 10 % samples exceeded the safety threshold. Significant differences in contents of Cr, Pb and Hg were found among the five investigated areas. Overall, the heavy metal levels in sea cucumber juveniles were relatively low and more attention should be paid to toxic metals Pb, Cd, As and Hg in future routine monitoring program.

  17. Mitochondrial DNA variation in the East China Sea and Yellow Sea populations of swimming crab Ovalipes punctatus.

    Science.gov (United States)

    Zheng, Wei; Han, Zhiqiang; Chen, Guobao; Yu, Cungen; Gao, Tianxiang

    2015-08-01

    Swimming crab Ovalipes punctatus is a commercially important species in the East China Sea and Yellow Sea, but there is limited knowledge of its genetic population structure. The population genetic structure of O. punctatus in East China Sea and Yellow Sea was examined with a 658-bp segment of the mtDNA COI gene. A total of 60 individuals were collected from five locations and 48 haplotypes were obtained. Mean haplotype diversity and nucleotide diversity for the five populations were 0.9876 ± 0.0068 and 0.0074 ± 0.0041, respectively. Analysis of molecular variance (AMOVA) detected no significant differences at all hierarchical levels, and all FST values were non-significant, indicating that no significant population genetic structure exists in the East China Sea and Yellow Sea. These results supported the null hypothesis that O. punctatus within the East China Sea and Yellow Sea constitutes a panmictic mtDNA gene pool. Neutrality tests and mismatch distribution supported population expansion in this species, indicating that climate change could play an important role in affecting the demographic history of marine species. Strong dispersal capacity of larvae and adults, and ocean currents in the studied area could be the reasons for genetic homogeneity in this species in the East China Sea and Yellow Sea. Another explanation for the lack of phylogeographic structure in O. punctatus might reflect a recent range expansion after the last glacial maximum and insufficient time to attain migration-drift equilibrium.

  18. Statistical Analysis of Acoustic Signal Propagating Through the South China Sea Basin

    Science.gov (United States)

    2016-03-01

    ANALYSIS OF ACOUSTIC SIGNAL PROPAGATING THROUGH THE SOUTH CHINA SEA BASIN by Meihuei Chen March 2016 Thesis Advisor...ACOUSTIC SIGNAL PROPAGATING THROUGH THE SOUTH CHINA SEA BASIN 5. FUNDING NUMBERS 6. AUTHOR(S) Meihuei Chen 7. PERFORMING ORGANIZATION NAME(S) AND...China Sea (SCS) basin to study the effects of nonlinear internal waves on 400- Hz acoustic signal propagation. The acoustic arrival structure for this

  19. Modern sedimentation and extreme event in the South China Sea

    Science.gov (United States)

    Chen, Yu-Huang; Su, Chih-Chieh

    2016-04-01

    The South China Sea is the largest marginal sea of the northwest Pacific. It is situated at the plate boundary of the Eurasian, Philippine Sea, and Indian plates and also on the North Western Pacific corridor of typhoons. The unique tectonic and climatic environment makes it has to face the potential of seafloor destructions, like submarine landslides and slumps, and high sediment discharges which induced by typhoon from Philippine. In this study, we analysis the sediment properties of modern extreme event records in cores and attempt to evaluate the history of extreme events in the South China Sea. Twelve gravity cores were collected in the central South China Sea basin and around Taiping island by using R/V Ocean Research 1 from 2014 to 2015 and a series of analysis including multi-sensor core logger, XRF core scanner (Itrax), core surface images, X-radiographs, bulk density, grain size, Pb-210 chronology and X-ray diffractometer were conducted in this study. On core surface images, an obvious brownish oxidized layer exist in core top with higher Pb-210 activity beneath this oxidized layer, and we speculate this layer is caused by nature hazard. According to the sampling time, we conjecture the oxidized layer might formed by typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippine. The sedimentation rate of the non-event years in these cores which derived from Pb-210 chronology method is about 0.02 ~0.03 cm/yr. On contrary, the event layer caused by Haiyan with a recorded maximum 87cm deposits in the South China Sea. This study aims to characterize the typhoon induced deposits in the turbidite layer and use it to identify whether the other event layers recorded in these cores were related to typhoon activities and to reconstruct the strong tropical cyclone history in the western Pacific.

  20. South China Sea Wave Characteristics During Typhoon Muifa Passage in Winter 2004

    National Research Council Canada - National Science Library

    Chu, Peter C; Cheng, Kuo-Feng

    2008-01-01

    Ocean wave characteristics in the western Atlantic Ocean (Hurricane Region) to tropical cyclones have been investigated extensively, but not the regional seas in the western Pacific such as the South China Sea (Typhoon Region...

  1. Distributions and sources of volatile chlorocarbons and bromocarbons in the Yellow Sea and East China Sea

    International Nuclear Information System (INIS)

    Yang, Bin; Yang, Gui-Peng; Lu, Xiao-Lan; Li, Li; He, Zhen

    2015-01-01

    Highlights: • Concentrations of the six VHOC were determined in the Yellow Sea and East China Sea. • VHOC distributions were affected by anthropogenic, biologic and hydrographic factors. • Diurnal variations of the six VHOC were observed. • Relationships between VHOC and related parameters were discussed. • Sources of the six VHOC were identified by principal component analysis. - Abstract: Six volatile halogenated organic compounds (VHOC), namely, chloroform, carbon tetrachloride, trichloroethylene, bromodichloromethane, dibromochloromethane, and bromoform, were studied in the Yellow Sea and East China Sea from April to May, 2009. The spatial variability of these VHOC was influenced by various factors, including anthropogenic inputs, biogenic production and complicated hydrographic features such as Changjiang Diluted Water, Yellow Sea Cold Water Mass, and Kuroshio Current. Diurnal study results showed that factors such as solar irradiation, biological activity, and tide affected the abundance of these VHOC. Correlation analyses revealed that bromodichloromethane was positively correlated with chlorophyll a in surface seawater. Principal component analysis suggested that chlorinated compounds like carbon tetrachloride originated from anthropogenic sources whereas brominated compounds such as bromodichloromethane originated from biogenic sources. Sources of other chlorinated and brominated compounds may not be governed by biological processes in the marine environment

  2. 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

    Science.gov (United States)

    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.

  3. Disputes About Disputes: Understanding the South China Sea

    Directory of Open Access Journals (Sweden)

    Bill Hayton

    2017-12-01

    Full Text Available Steve Chan. China’s Troubled Waters: Maritime Disputes in Theoretical Perspectives. Cambridge: Cambridge University Press, 2016. Do Thanh Hai. Vietnam and the South China Sea: Politics, Security and Legality. New York: Routledge, 2017. The two books under review here demonstrate some of the diversity of writing within the discipline of international relations. In China’s Troubled Waters: Maritime Disputes in Theoretical Perspectives, political scientist Steve Chan, following Kant, describes his style as “nomothetic,” “which emphasizes attention to classes of events rather than specific episodes” (vii. Strategic and defense studies scholar Do Thanh Hai’s Vietnam and the South China Sea: Politics, Security and Legality is an example of what Chan calls the “idiographic approach,” focusing “on the more unique or specific aspects of the situation” (vii. Chan wants to be able to generalize and compare, and he explicitly eschews narratives of “who did what to whom.” Hai, on the other hand, is keen to make clear that it is China who did something to Vietnam. The most obvious criticism to make of his book is that it is written from an overtly Vietnamese perspective. That is a weakness, but also potentially a draw for those interested in the formulation of Vietnamese policy. Chan writes from an ostensibly neutral position, but, as we shall see, his analysis is rooted within a Chinese world view.

  4. Satellite based wind resource assessment over the South China Sea

    DEFF Research Database (Denmark)

    Badger, Merete; Astrup, Poul; Hasager, Charlotte Bay

    2014-01-01

    years of WRF data – specifically the parameters heat flux, air temperature, and friction velocity – are used to calculate a long-term correction for atmospheric stability effects. The stability correction is applied to the satellite based wind resource maps together with a vertical wind profile...... from satellite synthetic aperture radar (SAR) data are particularly suitable for offshore wind energy applications because they offer a spatial resolution up to 500 m and include coastal seas. In this presentation, satellite wind maps are used in combination with mast observations and numerical...... modeling to develop procedures and best practices for satellite based wind resource assessment offshore. All existing satellite images from the Envisat Advanced SAR sensor by the European Space Agency (2002-12) have been collected over a domain in the South China Sea. Wind speed is first retrieved from...

  5. Comparative study of SEA experiences between EU and China

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    making, such as: How inclusive will the system be in relation to environmental, economic and social indicators? And how can the appropriate aggregation level for indicators be found? This paper makes a comparative study of the experiences of using indicators in SEA in two European countries and China......, in order to investigate the following questions: Are indicators used when performing an assessment? How are they used? Do indicators lead to opportunities or limitations in an evaluation process? And, are they positive or negative in providing information for decision making? Through a review of national...

  6. Floating Algae Blooms in the East China Sea

    Science.gov (United States)

    Qi, Lin; Hu, Chuanmin; Wang, Mengqiu; Shang, Shaoling; Wilson, Cara

    2017-11-01

    A floating algae bloom in the East China Sea was observed in Moderate Resolution Imaging Spectroradiometer (MODIS) imagery in May 2017. Using satellite imagery from MODIS, Visible Infrared Imaging Radiometer Suite, Geostationary Ocean Color Imager, and Ocean Land Imager, and combined with numerical particle tracing experiments and laboratory experiments, we examined the history of this bloom as well as similar blooms in previous years and attempted to trace the bloom source and identify the algae type. Results suggest that one bloom origin is offshore Zhejiang coast where algae slicks have appeared in satellite imagery almost every February-March since 2012. Following the Kuroshio Current and Taiwan Warm Current, these "initial" algae slicks are first transported to the northeast to reach South Korea (Jeju Island) and Japan coastal waters (up to 135°E) by early April 2017, and then transported to the northwest to enter the Yellow Sea by the end of April. The transport pathway covers an area known to be rich in Sargassum horneri, and spectral analysis suggests that most of the algae slicks may contain large amount of S. horneri. The bloom covers a water area of 160,000 km2 with pure algae coverage of 530 km2, which exceeds the size of most Ulva blooms that occur every May-July in the Yellow Sea. While blooms of smaller size also occurred in previous years and especially in 2015, the 2017 bloom is hypothesized to be a result of record-high water temperature, increased light availability, and continuous expansion of Porphyra aquaculture along the East China Sea coast.

  7. Management implications of fish trap effectiveness in adjacent coral reef and gorgonian habitats

    Science.gov (United States)

    Wolff, Nicholas; Grober-Dunsmore, Rikki; Rogers, Caroline S.; Beets, James P.

    1999-01-01

    A combination of visual census and trap sampling in St. John, USVI indicated that traps performed better in gorgonian habitat than in adjacent coral reef habitat. Although most families were seen more commonly in coral habitat, they were caught more often in gorgonian areas. Traps probably fished more effectively in gorgonian habitats, especially for migrating species, because traps provided shelter in the relatively topographically uniform environment of gorgonian dominated habitats. Recently, trap fishermen on St. John have been moving effort away from traditionally fished nearshore coral reefs and into a variety of more homogeneous habitats such as gorgonian habitat. Consequently, exploitation rates of the already over-harvested reef fish resources may be increasing. Reef fish managers and marine reserve designers should consider limiting trap fishing in gorgonian habitats to slow the decline of reef fisheries.

  8. Climate extremes in Malaysia and the equatorial South China Sea

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    2016-09-01

    Evidence of Economic Interdependence The Vietnam and Philippine economies have grown increasingly dependent on China. Vietnam began growing more...in the South China Sea. As Vietnam and the Philippines recognized the vulnerabilities they incurred with their dependence on China’s economy , the...if backed by a strong, responsible security partner, as conflict in the South China Sea would severely impact China’s economy . If Vietnam and the

  10. Population genetic structure of the mantis shrimp Oratosquilla oratoria (Crustacea: Squillidae) in the Yellow Sea and East China Sea

    Science.gov (United States)

    Yang, Mei; Li, Xinzheng

    2017-09-01

    The mantis shrimp Oratosquilla oratoria is an ecologically and economically important species in the Western Pacific. In present study, the population genetic structure of Oratosquilla oratoria from the Yellow Sea and East China Sea was examined with mitochondrial DNA control region sequences. In total, 394 samples were collected from 18 locations and 102 haplotypes were obtained. For the Yellow Sea, the overall nucleotide diversity and haplotype diversity were 0.006 9 and 0.946 8, respectively; while across all the East China Sea locations, the overall nucleotide diversity and haplotype diversity were 0.027 94 and 0.979 0, respectively. The results of AMOVA and pairwise F ST (0.145 2, P <0.001) revealed moderate differentiation between the Yellow Sea and East China Sea populations of O. oratoria. However, neither the neighbor-joining tree nor haplotype network showed clades with geographic pattern, which indicated considerable gene flow was existed between the Yellow Sea and East China Sea, and supporting the high larval dispersal ability in this species. Mismatch distribution analysis and neutrality tests suggested that O. oratoria has undergone population expansion event, and the Pleistocene glacial cycles might have an impact on the historical demography of O. oratoria. The genetic information obtained in this study can provide useful information for sustainable improvements for capture fisheries management strategies.

  11. Maritime Territorialisation as Performance of Sovereignty and Nationhood in the South China Sea

    DEFF Research Database (Denmark)

    Roszko, Edyta

    2015-01-01

    The South China Sea (SCS) is a conflict-ridden international arena of rivalry between China, the US, India, and the other ASEAN countries over sovereignty, resources and security. In this geo-political clash China is the dominant force and Vietnam its main challenger. While most analysts assume...

  12. Origin of the Dongsha Event in the South China Sea

    Science.gov (United States)

    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.

  13. Sedimentary records of Typhoon Haiyan in the South China Sea

    Science.gov (United States)

    Su, C. C.; Chen, Y. H.; Chang, J. H.; Hsu, H. H.; Yu, P. S.; Liu, C. S.

    2016-12-01

    South China Sea (SCS), which is located at the boundary of the Eurasian, Philippine Sea, and Indian plates, is the largest marginal sea of the northwest Pacific and also on the North Western Pacific corridor of typhoons. The unique tectonic setting and climatic conditions make it has to face the severe natural hazards, like submarine landslides, and high sediment discharges which induced by typhoon. On November 8, 2013, the Typhoon Haiyan, which was one of the largest tropical cyclones ever recorded in western Pacific, devastated Philippines and caused catastrophic destruction. Before the Typhoon Haiyan reached Hainan Province, China and Quangninh Province, Vietnam, it emerged over the SCS. How was the large amount of terrestrial materials distributed and recorded in deep sea sediments by such intense typhoon? Is it possible for us to reconstruct the history of extreme tropical cyclones by using deep sea cores? In this study, twelve gravity cores were collected in the Central SCS Basin and around Taiping Island (Itu Aba Island) from 2014 to 2015 and a series of analysis including Multi-Sensor Core Logger, XRF Core Scanner, core surface and X-radiograph images, grain size, and excess 210Pb chronology were conducted for modern extreme event records in cores and attempt to evaluate the possibility of reconstructed extreme typhoon records in cores from the SCS. On core surface images, an obvious brownish oxidized layer exist in core top with higher 210Pb activities beneath the layer. According to the sampling time, we conjecture the oxidized layer might formed by Typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippines. The Power Barge 103 of Napocor in Estancia IIoilo was dislodged from its mount by Typhoon Haiyan and the United Nations Disaster Assessment and Coordination Team reported 600,000 liters of bunker

  14. Sea-level trend in the South China Sea observed from 20 years of along-track satellite altimetric data

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Xu, Qing; Andersen, Ole Baltazar

    2014-01-01

    The sea-level trend in the South China Sea (SCS) is investigated based on 20 years of along-track data from TOPEX and Jason-1/2 satellite altimetry. The average sea-level rise over all the regions in the study area is observed to have a rate of 5.1 ± 0.8 mm year-1 for the period from 1993 to 2012...

  15. Sea level change under IPCC-A2 scenario in Bohai, Yellow, and East China Seas

    Directory of Open Access Journals (Sweden)

    Chang-lin Chen

    2014-10-01

    Full Text Available Because of the environmental and socioeconomic impacts of anthropogenic sea level rise (SLR, it is very important to understand the processes leading to past and present SLRs towards more reliable future SLR projections. A regional ocean general circulation model (ROGCM, with a grid refinement in the Bohai, Yellow, and East China Seas (BYECSs, was set up to project SLR induced by the ocean dynamic change in the 21st century. The model does not consider the contributions from ice sheets and glacier melting. Data of all forcing terms required in the model came from the simulation of the Community Climate System Model version 3.0 (CCSM3 under the International Panel on Climate Change (IPCC-A2 scenario. Simulation results show that at the end of the 21st century, the sea level in the BYECSs will rise about 0.12 to 0.20 m. The SLR in the BYECSs during the 21st century is mainly caused by the ocean mass redistribution due to the ocean dynamic change of the Pacific Ocean, which means that water in the Pacific Ocean tends to move to the continental shelves of the BYECSs, although the local steric sea level change is another factor.

  16. Circulation and oxygenation of the glacial South China Sea

    Science.gov (United States)

    Li, Dawei; Chiang, Tzu-Ling; Kao, Shuh-Ji; Hsin, Yi-Chia; Zheng, Li-Wei; Yang, Jin-Yu Terence; Hsu, Shih-Chieh; Wu, Chau-Ron; Dai, Minhan

    2017-05-01

    Degree of oxygenation in intermediate water modulates the downward transferring efficiency of primary productivity (PP) from surface water to deep water for carbon sequestration, consequently, the storage of nutrients versus the delivery and sedimentary burial fluxes of organic matter and associated biomarkers. To better decipher the PP history of the South China Sea (SCS), appreciation about the glacial-interglacial variation of the Luzon Strait (LS) throughflow, which determines the mean residence time and oxygenation of water mass in the SCS interior, is required. Based on a well-established physical model, we conducted a 3-D modeling exercise to quantify the effects of sea level drop and monsoon wind intensity on glacial circulation pattern, thus, to evaluate effects of productivity and circulation-induced oxygenation on the burial of organic matter. Under modern climatology wind conditions, a 135 m sea-level drop results in a greater basin closeness and a ∼24% of reduction in the LS intermediate westward throughflow, consequently, an increase in the mean water residence time (from 19.0 to 23.0 years). However, when the wind intensity was doubled during glacial low sea-level conditon, the throughflow restored largely to reach a similar residence time (18.4 years) as today regardless its closeness. Comparing with present day SCS, surface circulation pattern in glacial model exhibits (1) stronger upwelling at the west off Luzon Island, and (2) an intensified southwestward jet current along the western boundary of the SCS basin. Superimposed hypothetically by stronger monsoon wind, the glacial SCS conditions facilitate greater primary productivity in the northern part. Manganese, a redox sensitive indicator, in IMAGES core MD972142 at southeastern SCS revealed a relatively reducing environment in glacial periods. Considering the similarity in the mean water residence time between modern and glacial cases, the reducing environment of the glacial southeastern SCS

  17. Indonesia in the South China Sea Dispute: Humble-Hard Power

    OpenAIRE

    Robertua, Verdinand; Sinaga, Obsatar

    2018-01-01

    This research discussed the opportunities for Indonesia to act as humble-hard power in South China Sea dispute. Permanent Court of Arbitration’s decision in July 2016 to give South China Sea based on UNCLOS’s regulation has provoked China’s objection. This research question is on how to understand the conception of humble-hard power and the possibility for Indonesia to be humble-hard power in the South China Sea dispute? This article borrowed the concept of humble-hard power from Adam Nieves ...

  18. [Geochemical distribution of dissolved bismuth in the Yellow Sea and East China Sea].

    Science.gov (United States)

    Wu, Xiao-Dan; Song, Jin-Ming; Wu, Bin; Li, Xue-Gang

    2014-01-01

    Occurrence level, geochemical distribution of dissolved bismuth and its coupling relationship to eco-environment were investigated in the Yellow Sea and East China Sea to explore the source and influencing factors. The results showed that the concentration of dissolved bismuth was within the range of 0-0. 029 microg x L(-1) at the surface and 0.001-0.189 microg x L(-1) at the bottom, with the averages of 0.008 and 0.016 microg x L(-1), respectively. Horizontally, low value of dissolved bismuth exhibited the bidirectional extension feature, indicating that it could trace the path of Changjiang Diluted Water. High value of dissolved bismuth was observed where the Subei Costal Current and Yellow Sea Warm Current flowed and the Changjiang Diluted Water and Zhejiang-Fujian Coastal Current met, suggesting that it was controlled by the cycle of current system. Vertically, the coastal water was fully mixed by water convection and eddy mixing, and was divided from the stratified water by strong tidal front, which blocked the transport of dissolved bismuth to the open sea. Thus, the concentration in front area was significantly higher than that in the open sea. Diurnal variation of dissolved bismuth was related to the hydrodynamic conditions (tide, suspension and thermocline) instead of the environmental factors (temperature and salinity). Positive relationship to SPM (suspended particulate matter) clarified that bismuth was prone to release from solid phase to liquid phase. Furthermore, conditions with temperature ranging 22-27 degrees C, salinity ranging 28-31 and pH ranging 7.9-8.1 were shown to be optimal for the release process.

  19. China’s Use of Peoples War Theory in the South China Sea

    Science.gov (United States)

    2017-05-25

    4 2 UNCLOS Maritime and Airspace Zones………………………………………………...5 1 Introduction China’s assertion of ownership of South China Sea...threatens global shipping lanes and the natural resources of Southeast Asian countries. Their assertion of ownership stems from a dynastic period where... guns , light cannons and advanced technology.46 On April 15th, the Chinese ordered the Philippines to remove their coast guard vessel from the Shoal

  20. Distribution of Atmospheric Aerosol over the South China Sea

    Directory of Open Access Journals (Sweden)

    Shih-Jen Huang

    2015-01-01

    Full Text Available The satellite-derived aerosol optical depth (AOD data is used to investigate the distribution of aerosol over the South China Sea (SCS. High correlation coefficients are found between in situ AERONET data and satellite AOD measurements around the SCS with the highest coefficient of 0.9 on the Dongsha Island (i.e., Pratas Island. The empirical orthogonal function (EOF analysis of AOD over the SCS shows that high AOD is always found around offshore areas of China, Indochina, Sumatra, and Borneo. Besides, spring is the major season of occurring coarse aerosol particles (AOT_C but fine aerosol particles (AOT_F occur yearly. The biomass burning is found in Indochina during March and April, and so it is in Sumatra and Borneo from August to October. The results also show that the AOT_F are higher during El Niño events, but higher AOT_C are found in La Niña years.

  1. The TKE dissipation rate in the northern South China Sea

    Science.gov (United States)

    Lozovatsky, Iossif; Liu, Zhiyu; Fernando, Harindra Joseph S.; Hu, Jianyu; Wei, Hao

    2013-12-01

    The microstructure measurements taken during the summer seasons of 2009 and 2010 in the northern South China Sea (between 18°N and 22.5°N, and from the Luzon Strait to the eastern shelf of China) were used to estimate the averaged dissipation rate in the upper pycnocline of the deep basin and on the shelf. Linear correlation between and the estimates of available potential energy of internal waves, which was found for this data set, indicates an impact of energetic internal waves on spatial structure and temporal variability of . On the shelf stations, the bottom boundary layer depth-integrated dissipation reaches 17-19 mW/m2, dominating the dissipation in the water column below the surface layer. In the pycnocline, the integrated dissipation was mostly ˜10-30 % of . A weak dependence of bin-averaged dissipation on the Richardson number was noted, according to , where ɛ 0 + ɛ m is the background value of for weak stratification and Ri cr = 0.25, pointing to the combined effects of shear instability of small-scale motions and the influence of larger-scale low frequency internal waves. The latter broadly agrees with the MacKinnon-Gregg scaling for internal-wave-induced turbulence dissipation.

  2. Monitoring Ulva prolifera in the Yellow Sea and East China Sea derived from multi-source remote sensing images

    Science.gov (United States)

    Yu, Dingfeng; Gai, Zhigang; Kong, Xiangfeng; Liu, Hui; Liu, Enxiao

    2017-11-01

    Ulva prolifera is a new type of marine ecological disaster in China. Since 2007, macroalgal blooms of Ulva prolifera occurred every summer in the Yellow Sea and East China Sea, causing significant environmental damage and economic loss especially for coastal areas. Because of its distribution range covering tens of thousands of square kilometers during its outbreak, it's obviously difficult to monitor using ship, and therefore the author of this article attempted to use remote sensing technology to monitor its temporal and spatial distribution.In the present study, CCD of China's Environmental Satellite and EOS-MODIS were employed to detect distribution of Ulva prolifera in the Yellow Sea and East China Sea in 2014.The remote sensing monitoring results show that early enteromorpha prolifera appeared not only in the sea adjacent to Yan Cheng, but also in the sea offshore from the Yangtze River estuary. Under the influence of favorable conditions, it drifted from south to north with the area gradually increased. During the period , its maximum area of the distribution reched to 3.5 square kilometers.

  3. Increasing eutrophication in the coastal seas of China from 1970 to 2050.

    Science.gov (United States)

    Strokal, Maryna; Yang, He; Zhang, Yinchen; Kroeze, Carolien; Li, Lili; Luan, Shengji; Wang, Huanzhi; Yang, Shunshun; Zhang, Yisheng

    2014-08-15

    We analyzed the potential for eutrophication in major seas around China: the Bohai Gulf, Yellow Sea and South China Sea. We model the riverine inputs of nitrogen (N), phosphorus (P) and silica (Si) to coastal seas from 1970 to 2050. Between 1970 and 2000 dissolved N and P inputs to the three seas increased by a factor of 2-5. In contrast, inputs of particulate N and P and dissolved Si, decreased due to damming of rivers. Between 2000 and 2050, the total N and P inputs increase further by 30-200%. Sewage is the dominant source of dissolved N and P in the Bohai Gulf, while agriculture is the primary source in the other seas. In the future, the ratios of Si to N and P decrease, which increases the risk of harmful algal blooms. Sewage treatment may reduce this risk in the Bohai Gulf, and agricultural management in the other seas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Impact of sea spray on the Yellow and East China Seas thermal structure during the passage of Typhoon Rammasun (2002)

    Science.gov (United States)

    Zhang, Lianxin; Zhang, Xuefeng; Chu, P. C.; Guan, Changlong; Fu, Hongli; Chao, Guofang; Han, Guijun; Li, Wei

    2017-10-01

    Strong winds lead to large amounts of sea spray in the lowest part of the atmospheric boundary layer. The spray droplets affect the air-sea heat fluxes due to their evaporation and the momentum due to the change of sea surface, and in turn change the upper ocean thermal structure. In this study, impact of sea spray on upper ocean temperatures in the Yellow and East China Seas (YES) during typhoon Rammasun's passage is investigated using the POMgcs ocean model with a sea spray parameterization scheme, in which the sea spray-induced heat fluxes are based on an improved Fairall's sea spray heat fluxes algorithm, and the sea spray-induced momentum fluxes are derived from an improved COARE version 2.6 bulk model. The distribution of the sea spray mediated turbulent fluxes was primarily located at Rammasun eye-wall region, in accord with the maximal wind speeds regions. When Rammasun enters the Yellow sea, the sea spray mediated latent (sensible) heat flux maximum is enhanced by 26% (13.5%) compared to that of the interfacial latent (sensible) heat flux. The maximum of the total air-sea momentum fluxes is enhanced by 43% compared to the counterpart of the interfacial momentum flux. Furthermore, the sea spray plays a key role in enhancing the intensity of the typhoon-induced "cold suction" and "heat pump" processes. When the effect of sea spray is considered, the maximum of the sea surface cooling in the right side of Rammasun's track is increased by 0.5°C, which is closer to the available satellite observations.

  5. Bothid larvae (Pleuronectiformes - Pisces) of the Gulf of Thailand and South China Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Devi, C.B.L.

    -1 53 BOTHID LARVAE (PLEURONECTIFORMES - PISCES) OF THE GULF OF THAILAND AND SOUTH CHINA SEA. C. B. LALITHAMBIKA DEVI National Institute of Oceanography, Regional Centre, Dr. Salim All Road, Kochi - 682031. ABSTRACTS The larvae of bothids were found...

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

    Science.gov (United States)

    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).

  7. Coupled dynamics of the South China Sea, the Sulu Sea, and the Pacific Ocean

    Science.gov (United States)

    Metzger, E. Joseph; Hurlburt, Harley E.

    1996-05-01

    The complex geometry, the seasonally reversing monsoon winds, and the connectivity with the Pacific Ocean all contribute to the coupled dynamics of the circulation in the South China Sea (SCS), the Sulu Sea, and the region around the Philippine Islands. The 1/2°, 1.5-layer global reduced gravity thermodynamic Navy layered ocean model (NLOM) is used to separate these components and to investigate the role of each one. When forced by the Hellerman and Rosenstein [1983] (HR) monthly wind stress climatology, the basic features of the model solution compare well with observations, and with higher-resolution NLOM versions. The dynamics of the flow from the Pacific Ocean into the SCS via the Luzon Strait are emphasized. The effects of Ekman suction/pumping due to wind curl are examined by forming monthly spatial averages of the winds over the SCS/Sulu Sea basins. This maintains a monthly varying stress but with a region of zero curl. Forcing the model with these modified winds leaves the mean Luzon Strait transport unchanged, and the variability actually increases slightly. These results suggest that it is the pressure head created by the pileup of water from the monsoonal wind stress that controls the variability of the Luzon Strait transport. The forcing for wind stress pileup effects could be either internal or external to the SCS/Sulu Sea basin. The effects of internal forcing are studied by applying monthly winds within this basin but annual HR winds outside the region. With this forcing the mean Luzon Strait transport is essentially unchanged, but the variability is only 44% of the standard case value. The external forcing is defined as zero stress in the SCS/Sulu Sea basins and HR monthly winds outside. Again, the mean Luzon Strait transport is unchanged, and here the variability is 60% of the standard case. The mean Luzon Strait transport is largely a function of the model geometry. When the Sulu archipelago is opened, a net cyclonic flow develops around the

  8. Potent Antifouling Marine Dihydroquinolin-2(1H)-one-Containing Alkaloids from the Gorgonian Coral-Derived Fungus Scopulariopsis sp.

    KAUST Repository

    Shao, Chang Lun

    2015-04-02

    Marine biofouling has a major economic impact, especially when it occurs on ship hulls or aquaculture facilities. Since the International Maritime Organization (IMO) treaty to ban the application of organotin-based paints to ships went into effect in 2008, there is an urgent demand for the development of efficient and environmentally friendly antifouling agents. Marine microorganisms have proved to be a potential source of antifouling natural compounds. In this study, six dihydroquinolin-2-one-containing alkaloids, three monoterpenoids combined with a 4-phenyl-3,4-dihydroquinolin-2(1H)-one (1–3) and three 4-phenyl-3,4-dihydroquinolin-2(1H)-one alkaloids (4–6), were isolated from the gorgonian coral-derived fungus Scopulariopsis sp. collected in the South China Sea. These dihydroquinolin-2-one-containing alkaloids were evaluated against the larval settlement of barnacle Balanus amphitrite, and antifouling activity was detected for the first time for this class of metabolites. All of them except 6 showed strong antifouling activity. Compounds 1 and 2 were discovered to be the most promising non-toxic antilarval settlement candidates. Especially, compound 1 is the strongest antifouling compound in nature until now which showed highly potent activity with picomolar level (EC50 17.5 pM) and a very safety and high therapeutic ratio (LC50/EC50 1200). This represents an effective non-toxic, anti-larval settlement structural class of promising antifouling lead compound. © 2015 Springer Science+Business Media New York

  9. Antimony and arsenic biogeochemistry in the East China Sea

    Science.gov (United States)

    Ren, Jing-Ling; Zhang, Xu-Zhou; Sun, You-Xu; Liu, Su-Mei; Huang, Daji; Zhang, Jing

    2016-02-01

    The biogeochemical cycles of the metalloid elements arsenic and antimony in the East China Sea (ECS), one of the most important marginal seas for western Pacific, were examined in May 2011. Dissolved inorganic arsenic (As(V) and As(III)) and antimony (Sb(V) and Sb(III)) species were determined by selective hydride generation-atomic fluorescence spectrometry (HG-AFS). Results show that total dissolved inorganic arsenic (TDIAs; [TDIAs]=[As(V)]+[As(III)]) were moderately depleted in the surface water and enriched in the deep water. Arsenite (As(III)) showed different vertical profiles with that of TDIAs, with significant surface enrichment in the middle shelf region where the concentrations of phosphate were extremely low. Speciation of dissolved arsenic was subtly controlled by the stoichiometric molar ratio of arsenate (As(V)) to phosphate. The average As(V)/P ratio for the ECS in spring 2011 was 10.8×10-3, which is higher than previous results and indicates the arsenate stress. The concentrations of total dissolved inorganic antimony (TDISb; [TDISb]=[Sb(V)]+[Sb(III)]) were high near the Changjiang Estuary and the coastal area of Hangzhou Bay and decreased moderately off the coast. TDISb displayed moderate conservative behavior in the ECS that confirms by the correlations with salinity and dissolved aluminum. Different with that of As(III), antimonite (Sb(III)) concentrations were extremely lower in the ECS, with relative higher concentration appeared at the bottom layer which indicates the contribution from sediment-water interface. A preliminary box model was established to estimate the water-mass balance and antimony budgets for the ECS. Compared with other areas in the world, the concentrations of dissolved inorganic arsenic and antimony in the ECS remain at natural levels.

  10. Quarter-Century Offshore Winds from SSM/I and WRF in the North Sea and South China Sea

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2016-09-01

    Full Text Available We study the wind climate and its long-term variability in the North Sea and South China Sea, areas relevant for offshore wind energy development, using satellite-based wind data, because very few reliable long-term in-situ sea surface wind observations are available. The Special Sensor Microwave Imager (SSM/I ocean winds extrapolated from 10 m to 100 m using the Charnock relationship and the logarithmic profile method are compared to Weather Research and Forecasting (WRF model results in both seas and to in-situ observations in the North Sea. The mean wind speed from SSM/I and WRF differ only by 0.1 m/s at Fino1 in the North Sea, while west of Hainan in the South China Sea the difference is 1.0 m/s. Linear regression between SSM/I and WRF winds at 100 m show correlation coefficients squared of 0.75 and 0.67, standard deviation of 1.67 m/s and 1.41 m/s, and mean difference of −0.12 m/s and 0.83 m/s for Fino1 and Hainan, respectively. The WRF-derived winds overestimate the values in the South China Sea. The inter-annual wind speed variability is estimated as 4.6% and 4.4% based on SSM/I at Fino1 and Hainan, respectively. We find significant changes in the seasonal wind pattern at Fino1 with springtime winds arriving one month earlier from 1988 to 2013 and higher winds in June; no yearly trend in wind speed is observed in the two seas.

  11. 137Cs inventories in the water column collected from the South and South China Seas

    International Nuclear Information System (INIS)

    Yamada, M.; Wang, Z.-L.; Zheng, J.

    2006-01-01

    Seawater samples were collected in the Sulu and South China Seas and their 137 Cs activities were determined by γ spectrometry. A significant difference in intermediate water 137 Cs activities in the 750-1500 m depth was observed between the Sulu and South China Seas. The 137 Cs inventories in the Sulu Sea was 5.7 times higher than that of the integrated deposition density of atmospheric global fallout at the same latitude of 0-10degN. A possible mechanism controlling this extremely high 137 Cs inventories may be inflows of 137 Cs rich North Pacific Tropical Water and upper North Pacific Intermediate Water through the Luzon Straight from the West Philippine Sea, and lateral transport across the Mindoro Strait into the Sulu Sea, then conveyance into the deep layer in the Sulu Sea basin. (author)

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

    Science.gov (United States)

    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.

  13. Interannual variability of the onset of the South China Sea summer monsoon

    OpenAIRE

    Luo, Ming; Leung, Yee; Graf, Hans-Friedrich; Herzog, Michael; Zhang, Wei

    2015-01-01

    This article investigates the year-to-year variability of the onset of the South China Sea summer monsoon (SCSSM) and the possible influences exerted by the surface temperature anomalies over land and sea. Early and late monsoon onsets are related to the temperature anomalies in different regions. It is found that an early onset follows negative sea surface temperature (SST) anomalies in the central tropical Pacific (CP) Ocean during the preceding winter and spring, corresponding to a CP La N...

  14. Methane in the South China Sea and the Western Philippine Sea

    Science.gov (United States)

    Tseng, Hsiao-Chun; Chen, Chen-Tung Arthur; Borges, Alberto V.; DelValls, T. Angel; Chang, Yu-Chang

    2017-03-01

    Approximately 700 water samples from the South China Sea (SCS) and 300 water samples from the western Philippine Sea (wPS) were collected during eight cruises from August 2003 to July 2007 to determine methane (CH4) distributions from the surface to a depth of 4250 m. The surface CH4 concentrations exceeded atmospheric equilibrium, both in the SCS and the wPS, and the concentrations were 4.5±3.6 and 3.0±1.2 nmol L-1, respectively. The sea-to-air fluxes were calculated, and the SCS and the wPS were found to emit CH4 to the atmosphere at 8.6±6.4 μmol m-2 d-1 and 4.9±4.9 μmol m-2 d-1, respectively. In the SCS, CH4 emissions were higher over the continental shelf (11.0±7.4 μmol m-2 d-1) than over the deep ocean (6.1±6.0 μmol m-2 d-1), owing to greater biological productivity and closer coupling with the sediments on the continental shelf. The SCS emitted 30.1×106 mol d-1 CH4 to the atmosphere and exported 1.82×106 mol d-1 CH4 to the wPS. The concentrations of both CH4 and chlorophyll a were high in the 150 m surface layer of the wPS, but were not significantly correlated with each other. CH4 concentrations generally declined with increasing depth below the euphotic zone but remained constant below 1,000 m, both in the SCS and the wPS. Some high CH4 concentrations were observed at mid-depths and bottom waters in the SCS, and were most likely caused by the release of CH4 from gas hydrates or gas seepage.

  15. South China sea off Viet Nam to see more exploration

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    British and Japanese operators are posed for exploration campaigns off southern Viet Nam. This paper reports that a 50-50 partnership of Lasmo International Ltd., London, and C. Itoh Exploration Co. of Japan signed a heads of agreement covering Block 04-2, and AEDC Vietnam Oil Development Co. and Teikoku Oil Co. acquired Block 05-3 under a production sharing contract. AEDC is a unit of AOC Energy Development Co., a subsidiary of Arabian Oil Co. (AOC) of Japan. Both tracts are in the Con Son basin in the South China Sea. Site is 15 km north of 500 million bbl Dai Hung (Big Bear) oil field for which state owned Petrovietnam is evaluating bids to place on production. A unit of the Royal Dutch/shell Group acquired a west offset, Block 10, early this year. The Lasmo-C. Itoh acreage is among five blocks offered in Vietnam's second round of offshore licensing. All are in the area that once was reserved entirely for Vietsovpetro, a partnership of Petrovietnam and the former Soviet Union

  16. Phytoplankton responses to aluminum enrichment in the South China Sea.

    Science.gov (United States)

    Zhou, Linbin; Liu, Jiaxing; Xing, Shuai; Tan, Yehui; Huang, Liangmin

    2018-04-01

    Compared to extensive studies reporting the aluminum (Al) toxicity to terrestrial plants and freshwater organisms, very little is known about how marine phytoplankton responds to Al in the field. Here we report the marine phytoplankton responses to Al enrichment in the South China Sea (SCS) using on-deck bottle incubation experiments during eight cruises from May 2010 to November 2013. Generally, Al addition alone enhanced the growth of diatom and Trichodesmium, and nitrogen fixation, but it inhibited the growth of dinoflagellates and Synechococcus. Nevertheless, Al addition alone did not influence the chlorophyll a concentration of the entire phytoplankton assemblages. By adding nitrate and phosphate simultaneously, Al enrichment led to substantial increases in chlorophyll a concentration (especially that of the picophytoplanktontrace metals including iron, we found that the phytoplankton responses to Al enrichment were relevant to nutrients coexisting in the environment. Al enrichment may give some phytoplankton a competitive edge over using nutrients, especially the limited ones. The possible influences of Al on the competitors and grazers (predators) of some phytoplankton might indirectly contribute to the positive responses of the phytoplankton to Al enrichment. Our results indicate that Al may influence marine carbon cycle by impacting phytoplankton growth and structure in natural seawater. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Mesh size selectivity of the gillnet in East China Sea

    Science.gov (United States)

    Li, L. Z.; Tang, J. H.; Xiong, Y.; Huang, H. L.; Wu, L.; Shi, J. J.; Gao, Y. S.; Wu, F. Q.

    2017-07-01

    A production test using several gillnets with various mesh sizes was carried out to discover the selectivity of gillnets in the East China Sea. The result showed that the composition of the catch species was synthetically affected by panel height and mesh size. The bycatch species of the 10-m nets were more than those of the 6-m nets. For target species, the effect of panel height on juvenile fish was ambiguous, but the number of juvenile fish declined quickly with the increase in mesh size. According to model deviance (D) and Akaike’s information criterion, the bi-normal model provided the best fit for small yellow croaker (Larimichthy polyactis), and the relative retention was 0.2 and 1, respectively. For Chelidonichthys spinosus, the log-normal was the best model; the right tilt of the selectivity curve was obvious and well coincided with the original data. The contact population of small yellow croaker showed a bi-normal distribution, and body lengths ranged from 95 to 215 mm. The contact population of C. spinosus showed a normal distribution, and the body lengths ranged from 95 to 205 mm. These results can provide references for coastal fishery management.

  18. High dark carbon fixation in the tropical South China Sea

    Science.gov (United States)

    Zhou, Weihua; Liao, Jianzu; Guo, Yajuan; Yuan, Xiangcheng; Huang, Hui; Yuan, Tao; Liu, Sheng

    2017-08-01

    Dark carbon fixation (DCF) has been usually assumed to be insignificant in the study of microbial production and carbon cycling. In order to evaluate DCF distribution and its contribution to biogenic carbon flux, surface and vertical distribution of DCF, primary production (PP) and bacterial production (BP) were investigated in both offshore and coastal waters in the South China Sea (SCS). Surface DCF was 0.058 μg C L-1 h-1 ( 10% of PP), within the same order of magnitude as BP of 0.047 μg C L-1 h-1 in the offshore waters. Integrated over the 1500 m water column, DCF was 196 mg C m-2 h-1, corresponding to 384% of PP, and represented a newly produced source of organic matter. This suggested that DCF was an important microbial metabolic pathway in the SCS, which might support 83% carbon demand of heterotrophic prokaryotes. Interestingly, the DCF was higher in the deep water ( 0.140 μg C L-1 h-1) than the surface water ( 0.089 μg C L-1 h-1). In addition to the different microbial community, this different vertical distribution of DCF was likely due to the nutrient status, as our nutrient enrichment experiment showed that the addition of glucose, ammonium and phosphate stimulated the DCF rates, especially the addition of glucose plus ammonium.

  19. 224Ra and its implications in the East China Sea

    International Nuclear Information System (INIS)

    Wu Men; Xiamen University, Xiamen; Fenfen Wang; Guangshan Liu

    2011-01-01

    The activities of 224 Ra in the East China Sea (ECS) were measured by the Mn-fiber adsorption-emanation method. The horizontal and vertical distributions of 224 Ra in the ECS in summer and winter were studied. The ranges of 224 Ra activities were 3 in summer with an average of 0.85 Bq/m 3 , and 3 in winter with an average of 0.72 Bq/m 3 . And the distributions of 224 Ra in the surface water were similar in these two seasons, decreasing rapidly with the increasing distance from the coast. The high 224 Ra area was located within 30-100 km offshore and the lowest activities appeared in the Kuroshio Current. The vertical distributions of 224 Ra showed two different characteristics. The horizontal and vertical eddy diffusion coefficients calculated by the one-dimensional state model of 224 Ra were (7.1-88.9) x 10 6 cm 2 /s and 2.18-163 cm 2 /s, respectively. The upwelling rates off Zhejiang Province were calculated from 224 Ra vertical distribution, which varied from 8.4 x 10 -3 cm/s to 13.3 x 10 -3 cm/s in summer and 16.3 x 10 -3 cm/s to 16.8 x 10 -3 cm/s in winter. (author)

  20. A Novel Roseosiphophage Isolated from the Oligotrophic South China Sea

    Directory of Open Access Journals (Sweden)

    Yunlan Yang

    2017-05-01

    Full Text Available The Roseobacter clade is abundant and widespread in marine environments and plays an important role in oceanic biogeochemical cycling. In this present study, a lytic siphophage (labeled vB_DshS-R5C infecting the strain type of Dinoroseobacter shibae named DFL12T, which is part of the Roseobacter clade, was isolated from the oligotrophic South China Sea. Phage R5C showed a narrow host range, short latent period and low burst size. The genome length of phage R5C was 77, 874 bp with a G+C content of 61.5%. Genomic comparisons detected no genome matches in the GenBank database and phylogenetic analysis based on DNA polymerase I revealed phylogenetic features that were distinct to other phages, suggesting the novelty of R5C. Several auxiliary metabolic genes (e.g., phoH gene, heat shock protein and queuosine biosynthesis genes were identified in the R5C genome that may be beneficial to the host and/or offer a competitive advantage for the phage. Among siphophages infecting the Roseobacter clade (roseosiphophages, four gene transfer agent-like genes were commonly located with close proximity to structural genes, suggesting that their function may be related to the tail of siphoviruses. The isolation and characterization of R5C demonstrated the high genomic and physiological diversity of roseophages as well as improved our understanding of host–phage interactions and the ecology of the marine Roseobacter.

  1. Sea surface cooling in the Northern South China Sea observed using Chinese Sea-wing Underwater Glider measurements

    Science.gov (United States)

    Qiu, C.; Mao, H.; Wu, J.

    2016-02-01

    Based on 26 days of Chinese Seawing underwater Glider measurements and satellite microwave data, we documented cooling of the upper mixed layer of the ocean in response to changes in the wind in the Northern South China Sea (NSCS) from September 19, 2014, to October 15, 2014. The Seawing underwater glider measured 177 profiles of temperature, salinity, and pressure within a 55 km נ55 km area, and reached a depth of 1000 m at a temporal resolution of 4 h. The study area experienced two cooling events, Cooling I and Cooling II, according to their timing. During Cooling I, water temperature at 1m depth (T1) decreased by 1.0°C, and the corresponding satellitederived surface winds increased locally by 4.2 m/s. During Cooling II, T1 decreased sharply by 1.7°C within a period of 4 days; sea surface winds increased by 7 m/s and covered the entire NSCS. The corresponding mixed layer depth (MLD) deepened sharply from 30 m to 60 m during Cooling II, and remained steady during Cooling I. We estimated temperature tendencies using a ML model. High resolution Seawing underwater glider measurements provided an estimation of MLD migration, allowing us to obtain the temporal entrainment rate of cool sub thermocline water. Quantitative analysis confirmed that the entrainment rate and latent heat flux were the two major components that regulated cooling of the ML, and that the Ekman advection and sensible heat flux were small.

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

    Directory of Open Access Journals (Sweden)

    M. Reyasudin Basir Khan

    2016-03-01

    Full Text Available 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]. Keywords: South China Sea, Solar radiation,wind speed, rainfall, microhydropower, PV system, Wind energy generation system

  3. Dynamics of the water circulations in the southern South China Sea and its seasonal transports

    DEFF Research Database (Denmark)

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

    2016-01-01

    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......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...

  4. On the recurrent Ulva prolifera blooms in the Yellow Sea and East China Sea

    Science.gov (United States)

    Hu, Chuanmin; Li, Daqiu; Chen, Changsheng; Ge, Jianzhong; Muller-Karger, Frank E.; Liu, Junpeng; Yu, Feng; He, Ming-Xia

    2010-05-01

    A massive bloom of the green macroalgae Ulva prolifera (previously known as Enteromorpha prolifera) occurred in June 2008 in the Yellow Sea (YS), resulting in perhaps the largest "green tide" event in history. Using a novel index (Floating Algae Index) and multiresolution remote sensing data from MODIS and Landsat, we show that U. prolifera patches appeared nearly every year between April and July 2000-2009 in the YS and/or East China Sea (ECS), which all originated from the nearshore Subei Bank. A finite volume numerical circulation model, driven by realistic forcing and boundary conditions, confirmed this finding. Analysis of meteorological/environmental data and information related to local aquaculture activities strongly supports the hypothesis that the recurrent U. prolifera in the YS and ECS resulted from aquaculture of the seaweed Porphyra yezoensis (or nori) conducted along the 200 km shoreline of the Subei Bank north of the Changjiang (Yangtze) River mouth. Given the continuous growth in aquaculture efforts in the region, similar macroalgae bloom events, such as the summer 2008 event, are likely to occur in the future, particularly between May and July. This was confirmed by the 2009 bloom event in the same regions and the same period. The profit of the local P. yezoensis aquaculture industry (˜16,000 Ha in 2007) is estimated as U.S. 53 million, yet the cost to manage the impact of the summer 2008 U. prolifera bloom exceeded U.S. 100 million. Therefore, better strategies are required to balance the economic benefit of seaweed aquaculture and the costs of environmental impacts.

  5. Assessment of marine debris in beaches or seawaters around the China Seas and coastal provinces.

    Science.gov (United States)

    Zhou, Changchun; Liu, Xu; Wang, Zhengwen; Yang, Tiantian; Shi, Linna; Wang, Linlin; You, Suwen; Li, Min; Zhang, Cuicui

    2016-02-01

    Compared with United States of America (USA), Brazil, Chile, Australia, limited attention has been paid to marine debris research in China and few studies have attempted to quantify the abundance and mass of marine debris. In this study, firstly the general status and sources of marine debris in China were assessed in the time period between 2007 and 2014, and secondly marine debris situation was evaluated in three China Sea Areas (the North China Sea, the East China Sea and the South China Sea) from 2009 to 2013, and finally marine debris conditions and sources were analyzed in beaches or seawaters around some coastal provinces of China during 2007-2013. Based on above analysis, the primary conclusions were as follows: (1) The mean number and weight densities of beached marine debris (BMD) and submerged marine debris (SMD) were 4.30, 0.13items/100m(2) and 133.80, 22.60g/100m(2) in China from 2007 to 2014, respectively. The average number density of the large size FMD (LOSFMD) was 0.0024items/100m(2) and that of the small and medium size FMD (SMSFMD) was 0.30items/100m(2), and the mean weight density of the SMSFMD was 1.40g/100m(2) from 2008 to 2014. The SMD and FMD densities were at the low level and the BMD density was at the high level in China. (2) The marine debris primarily was comprised of plastic, Styrofoam, wood, glass, rubber, fabric/fiber and metal, which included almost all major categories of marine debris. (3) Sources of BMD and FMD were as follows: the first source was coastal/recreational activities, followed by other disposal sources, navigation/fishing activities and the activities related smoking, and the least source being those associated with medical/sanitary activities, while the source of SMD remained unknown. (4) The mean number and weight densities of BMD were the biggest in the North China Sea, while those of FMD and SMD were the highest in the northern South China Sea. The results of this study were beneficial to the establishment of

  6. Overview on the distribution of gorgonian species in Tunisian marine coastal waters (central Mediterranean

    Directory of Open Access Journals (Sweden)

    Raouia Ghanem

    2018-03-01

    Full Text Available Gorgonian species play an important ecological role in the structure and function of marine communities. Human activities are negatively affecting the conservation status of gorgonian populations in the Mediterranean. Acquiring knowledge of gorgonian distribution is therefore a key step required to promote efficient management and conservation actions. However, information on the distribution of gorgonian species is lacking in many Mediterranean areas. This study aimed to provide an overview of the geographic and bathymetric distributions of gorgonians in the coastal waters of the Tunisian coast (1136 km. The sampling design encompassed three sectors, 27 localities and 87 sites. Information was collected from scuba diving (26 sites and local ecological knowledge surveys of fishermen and divers (132 interviews, as well as from a literature review. Overall, the occurrence of eight gorgonians was confirmed at 54 out of the 87 sites surveyed in Tunisian coastal waters (7-120 m depth. The species that were found were Eunicella singularis, Eunicella cavolini, Paramuricea clavata, Paramuricea macrospina, Leptogorgia sarmentosa, Eunicella verrucosa, Corallium rubrum and Ellisella paraplexauroides. The highest gorgonian species richness and abundance was recorded in northern, followed by eastern Tunisian waters. In the southern areas only one species was recorded. This pattern was related to the rocky substrate that characterizes the northern and eastern coasts of Tunisia. This study is the first to report the occurrence of E. singularis, E. cavolini, E. verrucosa and Leptogorgia sarmentosa in northern and eastern Tunisian waters. The results are discussed in the hope of guiding future conservation and management actions for gorgonian assemblages in Tunisia.

  7. Quarter-Century Offshore Winds from SSM/I and WRF in the North Sea and South China Sea

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Astrup, Poul; Zhu, Rong

    2016-01-01

    Imager (SSM/I) ocean winds extrapolated from 10 m to 100 m using the Charnock relationship and the logarithmic profile method are compared to Weather Research and Forecasting (WRF) model results in both seas and to in-situ observations in the North Sea. The mean wind speed from SSM/I and WRF differ only...... by 0.1 m/s at Fino1 in the North Sea, while west of Hainan in the South China Sea the difference is 1.0 m/s. Linear regression between SSM/I and WRF winds at 100 m show correlation coefficients squared of 0.75 and 0.67, standard deviation of 1.67 m/s and 1.41 m/s, and mean difference of −0.12 m/s and 0.......83 m/s for Fino1 and Hainan, respectively. The WRF-derived winds overestimate the values in the South China Sea. The inter-annual wind speed variability is estimated as 4.6% and 4.4% based on SSM/I at Fino1 and Hainan, respectively. We find significant changes in the seasonal wind pattern at Fino1...

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

    Science.gov (United States)

    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].

  9. Cretaceous–Eocene provenance connections between the Palawan Continental Terrane and the northern South China Sea margin

    NARCIS (Netherlands)

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

    2017-01-01

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Farshid Daryabor

    Full Text Available 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.

  13. Decadal variations in diatoms and dinoflagellates on the inner shelf of the East China Sea, China

    Science.gov (United States)

    Abate, Rediat; Gao, Yahui; Chen, Changping; Liang, Junrong; Mu, Wenhua; Kifile, Demeke; Chen, Yanghang

    2017-11-01

    Diatoms and dinoflagellates are two major groups of phytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world seas. However, this information is not available in the coastal East China Sea (ECS). Thus, to investigate and compare the decadal trends in diatoms and dinoflagellates, a sediment core, 47 cm long, was collected from the coastal zone of the ECS. Sediment chlorophyll- a (Chl- a), phytoplankton-group specific pigment signatures of diatoms and dinoflagellates, and diatom valve concentrations were determined. The sediment core covered the period from 1961 to 2011 AD. The chlorophyll- a contents ranged from 2.32 to 73 µg/g dry sediment (dw) and averaged 9.81 µg/g dw. Diatom absolute abundance ranged from 29152 to 177501 valve/gram (v/g) dw and averaged 72137 v/g dw. Diatom valve and diatom specific pigment marker concentrations were not significantly correlated. Peridinin increased after the 1980s in line with intensified use of fertilizer and related increases in nutrient inputs into the marine environment. The increased occurrence of dinoflagellate dominance after the 1980s can be mostly explained by the increase in nutrients. However, the contribution of dinoflagellates to total phytoplankton production (Chl- a) decreased during the final decade of this study, probably because of the overwhelming increase in diatom production that corresponded with the construction of the Three Gorges Dam (TGD) and related light availability. Similarly, the mean ratio of fucoxanthin/peridinin for the period from 1982 to 2001 was 6% less than for 1961 to 1982, while the ratio for 2001 to 2011 was 45.3% greater than for 1982 to 2001. The decadal variation in the fucoxanthin/peridinin ratio implies that dinoflagellate production had been gradually increasing until 2001. We suggest that the observed changes can be explained by anthropogenic impacts, such as nutrient

  14. Analysis of sea use landscape pattern based on GIS: a case study in Huludao, China.

    Science.gov (United States)

    Suo, Anning; Wang, Chen; Zhang, Minghui

    2016-01-01

    This study aims to analyse sea use landscape patterns on a regional scale based on methods of landscape ecology integrated with sea use spatial characteristics. Several landscape-level analysis indices, such as the dominance index, complex index, intensivity index, diversity index and sea congruency index, were established using Geographic Information System (GIS) and applied in Huludao, China. The results indicated that sea use landscape analysis indices, which were created based on the characteristics of sea use spatial patterns using GIS, are suitable to quantitatively describe the landscape patterns of sea use. They are operable tools for the landscape analysis of sea use. The sea use landscape in Huludao was dominated by fishing use with a landscape dominance index of 0.724. The sea use landscape is a complex mosaic with high diversity and plenty of fishing areas, as shown by the landscape complex index of 27.21 and the landscape diversity index of 1.25. Most sea use patches correspond to the marine functional zonation plan and the sea use congruency index is 0.89 in the fishing zone and 0.92 in the transportation zone.

  15. UNITED STATES NAVAL STRATEGY IN THE SOUTH CHINA SEA TO ENSURE INTERNATIONAL FREEDOM OF NAVIGATION

    Science.gov (United States)

    2016-02-12

    most corrupt, dysfunctional, intractable , and poverty-stricken societies in maritime Asia.”29 Such dysfunction has led to an inability to control...flow of goods, protecting U.S. natural resources, promoting stability, deterring conflict , and responding to aggression.”41 Specifically regarding...strategies of China, Vietnam and the Philippines conflict or enhance the US national strategy? Regional Countries South China Sea Strategy There are two

  16. A South China Sea Adiz-Vietnam’s Next Challenge

    Science.gov (United States)

    2016-06-01

    academic associate. Without him, I would not have completed this thesis on schedule. Last, but not least, my deepest appreciation goes to Cheryldee...claims in the South China Sea between China, Vietnam, the Philippines, Indonesia, Malaysia , Brunei, and Taiwan have spilled over onto issues such as...drawn mostly from published academic research and foreign policy news journals. With regard to the more recent ECS ADIZ, the Congressional Research

  17. Reevaluating the Context of U.S. Strategy In the South China Sea

    Science.gov (United States)

    2017-04-30

    Philippines , Vietnam to explore joint patrols in South China Sea.” 67. Department of Defense, Military and Security Developments Involving the...of Foreign Affairs and the Office of International Military Cooperation (OIMC) during the Air War College delegation visit on 27 February, 2017...Brookings (August 2014). Bello, Warren. “A Budding Alliance: Vietnam and the Philippines Confront China.” Foreign Policy in Focus, 18 March 2014

  18. Managing potential conflicts in the South China Sea

    International Nuclear Information System (INIS)

    Wisnumurti, N.

    1994-01-01

    The strategic significance of the South China Sea (SCS) is beyond doubt. The four workshops conducted so far have discussed a wide range of issues and areas for possible cooperation, instead of focusing on the factors-sovereignty and territorial claims-for conflict. They have shown the potential for such cooperation. Various proposals offered and the principles enunciated offer sufficient evidence for this. By expanding cooperation on less contentious issues on the basis of common interest and mutual benefit, an atmosphere more conducive to productive negotiations has been created. Such informal meetings and contacts can continue to play an important part in clarifying the issues involved and in furthering the regional marine agenda. These workshops are virtually risk-free for the Governments concerned; in fact, they could benefit from the plethora of proposals and recommendations that have emanated from these endeavours, which have also created a more cooperative environment for dialogue among the SCS States. In sum, the workshop process is a novel approach to conflict prevention and avoidance. Yet some pertinent questions need to be raised. Where do we go from here? Will the numerous proposals and recommendations discussed at length simply be filed? Do the SCS States have the necessary political will to implement them in a spirit of cooperation and compromise? Hence, the issue of formal meetings, institutions and/or mechanisms should now be considered. The role of such structures, possibly modelled on the experience gained by Western Europe and the South Pacific, where agencies have been established for designated areas to act on behalf of the regional States, warrants serious attention. What is called for at this juncture is the concretization of specific cooperative projects of a non-controversial nature. Such endeavours would ultimately lead to a 'sense of community' among the littoral States. However, cooperation for resource exploitation does not appear

  19. Expansion of the South China Sea basin: Constraints from magnetic anomaly stripes, sea floor topography, satellite gravity and submarine geothermics

    Directory of Open Access Journals (Sweden)

    Xuezhong Yu

    2017-01-01

    Full Text Available The widely distributed E–W-trending magnetic anomaly stripes in the central basin and the N–E-trending magnetic anomaly stripes in the southwest sub-basin provide the most important evidence for Neogene expansion of the South China Sea. The expansion mechanism remains, however, controversial because of the lack of direct drilling data, non-systematic marine magnetic survey data, and irregular magnetic anomaly stripes with two obvious directions. For example, researchers have inferred different ages and episodes of expansion for the central basin and southwest sub-basin. Major controversy centers on the order of basinal expansion and the mechanism of expansion for the entire South China Sea basin. This study attempts to constrain these problems from a comprehensive analysis of the seafloor topography, magnetic anomaly stripes, regional aeromagnetic data, satellite gravity, and submarine geothermics. The mapped seafloor terrain shows that the central basin is a north-south rectangle that is relatively shallow with many seamounts, whereas the southwest sub-basin is wide in northeast, gradually narrows to the southwest, and is relatively deeper with fewer seamounts. Many magnetic anomaly stripes are present in the central basin with variable dimensions and directions that are dominantly EW-trending, followed by the NE-, NW- and NS-trending. Conversely such stripes are few in the southwest sub-basin and mainly NE-trending. Regional magnetic data suggest that the NW-trending Ailaoshan-Red River fault extends into the South China Sea, links with the central fault zone in the South China Sea, which extends further southward to Reed Tablemount. Satellite gravity data show that both the central basin and southwest sub-basin are composed of oceanic crust. The Changlong seamount is particularly visible in the southwest sub-basin and extends eastward to the Zhenbei seamount. Also a low gravity anomaly zone coincides with the central fault zone in the sub

  20. Antibiotics in the offshore waters of the Bohai Sea and the Yellow Sea in China: Occurrence, distribution and ecological risks

    International Nuclear Information System (INIS)

    Zhang, Ruijie; Tang, Jianhui; Li, Jun; Zheng, Qian; Liu, Di; Chen, Yingjun; Zou, Yongde; Chen, Xiaoxiang; Luo, Chunling; Zhang, Gan

    2013-01-01

    The ocean is an important sink of land-based pollutants. Previous studies showed that serious antibiotic pollution occurred in the coastal waters, but limited studies focused on their presence in offshore waters. In this study, eleven antibiotics in three different categories were investigated in offshore waters of the Bohai Sea and the Yellow Sea in China. The results indicated that three antibiotics dehydration erythromycin, sulfamethoxazole and trimethoprim occurred throughout the offshore waters at concentrations of 0.10–16.6 ng L −1 and they decreased exponentially from the rivers to the coastal and offshore waters. The other antibiotics all presented very low detection rates ( −1 ). Although the concentrations were very low, risk assessment based on the calculated risk quotients (RQs) showed that sulfamethoxazole, dehydration erythromycin and clarithromycin at most of sampling sites posed medium or low ecological risks (0.01 −1 . ► Their concentrations decreased exponentially from the rivers to the offshore waters. ► Some antibiotics in the offshore water posed medium or low risks to some organisms. -- Some antibiotics were ubiquitous in the offshore waters of the Bohai Sea and the Yellow Sea in China and posed medium or low ecological risks to some sensitive organisms

  1. Case studies: Application of SEA in provincial level expressway infrastructure network planning in China - Current existing problems

    International Nuclear Information System (INIS)

    Zhou Kaiyi; Sheate, William R.

    2011-01-01

    Since the Law of the People's Republic of China on Environmental Impact Assessment was enacted in 2003 and Huanfa 2004 No. 98 was released in 2004, Strategic Environmental Assessment (SEA) has been officially being implemented in the expressway infrastructure planning field in China. Through scrutinizing two SEA application cases of China's provincial level expressway infrastructure (PLEI) network plans, it is found that current SEA practice in expressway infrastructure planning field has a number of problems including: SEA practitioners do not fully understand the objective of SEA; its potential contributions to strategic planning and decision-making is extremely limited; the employed application procedure and prediction and assessment techniques are too simple to bring objective, unbiased and scientific results; and no alternative options are considered. All these problems directly lead to poor quality SEA and consequently weaken SEA's effectiveness.

  2. Time trends of polybrominated diphenyl ethers in East China Seas: Response to the booming of PBDE pollution industry in China.

    Science.gov (United States)

    Li, Yuanyuan; Lin, Tian; Hu, Limin; Feng, Jialiang; Guo, Zhigang

    2016-01-01

    The East China Seas (ECSs) are the receptors of the land-based persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs) mainly from China through atmospheric deposition driven by the East Asian winter monsoon and fluvial discharge (e.g., Yangtze River and Yellow River), making the offshore sediments to be a good proxy to reconstruct history of those pollutants in China. In this work, four well-placed sediment cores were extracted from the mud areas in the ECSs, and the (210)Pb-dated cores were analyzed to yield historical concentration profiles of PBDEs in the area. The results showed that there was a persistent increase from 1970s and almost no clear sign in the decline of PBDEs until recently in China. More importantly, there was a faster increase of PBDEs from 1990s in China; while this period was just shown as gradually leveling off or even declining trends in developed countries. The persistently increasing trend of PBDEs in China since 1990s could be largely due to the booming of the manufacturing industry and unexpectedly transfer of PBDE pollution from developed countries to China. Besides, the relative high concentrations and fluxes of PBDEs in the core from coastal ECS located near a well-known electrical/electronic waste (e-waste) recycling area suggests an important contribution of PBDE emissions from recycling centers of e-waste in China. Although efforts in environmental monitoring of PBDE contamination have been substantially increased over the last decade, China is still lagging behind in terms of nationwide regulation of PBDE usage and treatment of disposal PBDE-containing products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Tension in the South China Sea: Why the Philippines is Challenging China’s Improved Military Might

    Science.gov (United States)

    2013-12-01

    China Sea (SCS) and occupation of territories claimed by the Philippines. Following the 1995 incident at Mischief Reef, Philippine foreign policy...2004. The Malaysian government increased its defense spending by over a billion dollars between 2001 and 2003.13 The ASEAN nations also started...Philippines, as well as cooperating in the safety of navigation and search and rescue operations. This agreement did not do much to quiet the tensions in

  4. New discovery on geopressured geothermal resources in China - case history from Ying-Qiong Basins, S. China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ji-yang; Xiong Liang-ping [Institute of Geology, Beijing (China)

    1996-12-31

    Geopressured geothermal resources are regarded as a new type of {open_quotes}high-energy-level{close_quotes} geothermal resources. In recent years, this kind of resources has been discovered in Ying-Qiong Basins at the northern margin of South China Sea. The geological environment and tectonic settings, geotemperature and heat flow pattern, high (over) pressure distribution and sedimentation rates of the basins as well as the perspectives of development and utilization of these resources were discussed briefly by the authors.

  5. China’s Historic Rights in the South China Sea: A Time for Reconsideration and Pacific Settlement

    Science.gov (United States)

    2014-05-18

    Law of the Sea (UNCLOS). 5 1 Jeff Himmelman, A Game of Shark and Minnow, N.Y. TIMES, (Oct...that an armed attack in the Pacific Area on either of the Parties would be dangerous to its own peace and safety and declares that it would act to...2013, October 27). A Game of Shark and Minnow. New York Times Magazine. Retrieved from http://www.nytimes.com/newsgraphics/ 2013/10/27/south-china

  6. Post-rift magmatism in the Pearl River Mouth Basin, northern South China Sea

    Science.gov (United States)

    Xu, H.; Zhao, F.; Xia, S.; Sun, J.; Fan, C.

    2017-12-01

    Multi-beam, 2D seismic reflection and borehole data reveal that post-rift magmatism are widespread in the northern margin of South China Sea. A large-scale volcanic complex was identified at water depths of 500 to 3000 m, covering an area of ca. 8000 km2. This volcanic complex includes seamounts, igneous sills, dykes and intruded volcanic bodies. Combining data from exploration wells BY7-1 and BY2 with published seismic stratigraphic data, we can highlight multiple extrusive events from the Early Oligocene to Early Miocene, reflecting progressive continental breakup in the South China Sea. Most intruded magma through the continental crust also uplifted sediments up to the T6 unconformity. Given the evidence in this work that Early Miocene magmatic bodies were developed above or along faults, we suggest that post-rift magmatism in the northern margin of the South China Sea was largely controlled by the faults. Reactivation events in the faults are suggested to have generated preferential vertical pathways for the ascent of magma within a context of progressive continental breakup and thinned continental crust, as the South China Sea was being formed.

  7. Numerical Forecasting Experiment of the Wave Energy Resource in the China Sea

    Directory of Open Access Journals (Sweden)

    Chong Wei Zheng

    2016-01-01

    Full Text Available The short-term forecasting of wave energy is important to provide guidance for the electric power operation and power transmission system and to enhance the efficiency of energy capture and conversion. This study produced a numerical forecasting experiment of the China Sea wave energy using WAVEWATCH-III (WW3, the latest version 4.18 wave model driven by T213 (WW3-T213 and T639 (WW3-T639 wind data separately. Then the WW3-T213 and WW3-T639 were verified and compared to build a short-term wave energy forecasting structure suited for the China Sea. Considering the value of wave power density (WPD, “wave energy rose,” daily and weekly total storage and effective storage of wave energy, this study also designed a series of short-term wave energy forecasting productions. Results show that both the WW3-T213 and WW3-T639 exhibit a good skill on the numerical forecasting of the China Sea WPD, while the result of WW3-T639 is much better. Judging from WPD and daily and weekly total storage and effective storage of wave energy, great wave energy caused by cold airs was found. As there are relatively frequent cold airs in winter, early spring, and later autumn in the China Sea and the surrounding waters, abundant wave energy ensues.

  8. Distribution of aliphatic and polycyclic aromatic hydrocarbon in South China sea sediments

    International Nuclear Information System (INIS)

    Md Suhaimi Elias; Ab Khalik Wood; Zaleha Hashim; Wee Boon Siong; Nazaratul Ashifa; Mohd Suhaimi Hamzah; Shamsiah Ab Rahman; Ariffin Talib

    2006-01-01

    Petroleum hydrocarbon (Hcp) consist of three major components namely alkanes, cyclo-alkanes and aromatics. HCP are pollutant and can cause adverse effect to the marine organisms. The study was done to identify the source of pollution in the South China Sea coastal area. The South China Sea is one of the major oil production area in Malaysia. Sampling was done at 15 stations along the coastal area of South China Sea off Peninsular Malaysia, which involved two zone namely coastal (zone 1) and offshore (zone 2) areas. Samples were analyzed using GC-MS for determination of HCP. The results showed, that concentration of aliphatic and polycyclic aromatic hydrocarbon at coastal area, range from 0.51 - 1.31 mg/g and 0.18 - 0.42 mg/g dry weight, respectively whilst, concentration of aliphatic and polycyclic aromatic hydrocarbon at offshore area, range from 0.44 - 1.09 mg/g and 0.20 - 0.49 mg/g dry weight, respectively. SHCP (Aliphatic + PAH) concentration in the sediment at the study area range from 0.64 - 1.68 mg/g dry weight. In this study, it was found that, pollution source for the South China Sea off Peninsular Malaysia was originated from pyrolytic sources (combustion fossil fuel), while some other area had been polluted by pyrolytic or petrogenic (unburned fossil) sources. (Author)

  9. Low-Frequency Variability of the Yellow Sea Cold Water Mass Identified from the China Coastal Waters and Adjacent Seas Reanalysis

    Science.gov (United States)

    2015-01-01

    266100, China 2Key Laboratory of Marine Environment Information Technology, SOA , National Marine Data and Information Service, Tianjin 300171,China...dominant pattern of nonseasonal sea level pressure variability north of 20∘N. It is characterized by sea level pressure anomalies with opposite signs in...surface temperature variability north of 20∘N in the North Pacific, and it is a long-lived El Niño-like pattern of the Pacific climate variability [21

  10. Chinese Assertiveness in the South China Sea and Southeast Asian Responses

    Directory of Open Access Journals (Sweden)

    Carlyle A. Thayer

    2011-01-01

    Full Text Available This article reviews Chinese assertive behaviour towards the Philippines and Vietnam over South China Sea issues in 2011. The article compares and contrasts Chinese diplomatic behaviour in the period before and after the adoption by ASEAN member states and China of Guidelines for the Implementation the Declaration on Conduct of Parties in the South China Sea in July. In the first period China aggressively asserted its claims to sovereignty by interfering with commercial fishing and oil exploration activities of vessels operating in the Exclusive Economic Zones of Vietnam and the Philippines. Both states resisted Chinese actions. The Philippines allocated increased funding for defence modernization, lobbied ASEAN states and shored up its alliance with the United States. Vietnam too protested Chinese action and undertook symbolic steps to defend national sovereignty. In the second period all states moved to contain South China Sea tensions from affecting their larger bilateral relations. It remains to be seen, however, if proposed confidence building measures will ameliorate Chinese assertiveness.

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

    Science.gov (United States)

    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).

  12. Sea Level Rise and Land Subsidence Contributions to the Signals from the Tide Gauges of China

    Science.gov (United States)

    Parker, Albert

    2016-06-01

    The tide gauges measure the local oscillations of the sea level vs. the tide gauge instrument. The tide gauge instrument is generally subjected to the general subsidence or uplift of the nearby inland, plus some additional subsidence for land compaction and other localised phenomena. The paper proposes a non-linear model of the relative sea level oscillations including a long term trend for the absolute sea level rise, another term for the subsidence of the instrument, and finally a sinusoidal approximation for the cyclic oscillations of periodicities up to decades. This non-linear model is applied to the tide gauges of China. The paper shows that the limited information available for China does not permit to infer any proper trend for the relative rates of rise, as the tide gauge records are all short or incomplete and the vertical movement of the tide gauge instruments is unassessed. The only tide gauge record of sufficient length that may be assembled for China is obtained by combining the North Point and Quarry Bay tide gauges in Hong Kong (NPQB). This NQPB composite tide gauge record is shown to have similarities with the tide gauge records of Sydney, equally in the West pacific, and San Diego, in the east Pacific, oscillating about the longer term trend mostly determined by the local subsidence. As it is very well known that China generally suffers of land subsidence, and the tide gauge installations may suffer of additional subsidence vs. the inland, it may be concluded from the analysis of the other worldwide tide gauges that the sea levels of China are very likely rising about the same amount of the subsidence of the tide gauges, with the sea level acceleration component still negligible.

  13. Ocean pollution from land-based sources: East China Sea, China.

    Science.gov (United States)

    Li, Daoji; Daler, Dag

    2004-02-01

    The environment of East China Sea (ECS) has been faced by huge stresses from anthropogenic activities and population growth in the Yangtze River drainage basin and the areas along the coasts. Improper use of natural resources and short-term economic objectives have resulted in severe environmental degradation in a fairly short time frame and the degradation has now reached a level where the health and well being of the coastal populations are threatened. The main pollutants are inorganic nitrogen, phosphate, oil hydrocarbons, organic matters and heavy metals. Nutrients cause eutrophication of the coastal waters and the estuarine area and very often stimulate the occurrence of red tides. The environmental pollution of Yangtze River basin directly impact on the state of the marine environment in the ECS. The ecosystem stability is maintained by a steady water discharge from the river, that mixes with the marine salty water in the estuary, and the sediment loads from the river that balance ocean erosion in the delta and its adjacent coastal area. The large-scale water transfer and dam constructions in the Yangtze River basin will change this basis. For the ECS the challenge is to reverse the negative processes taking place and to restore ecosystem balance. The main challenge is to integrate socioeconomic and environmental decision making in order to promote sustainable development. A better understanding of the driving forces in society that cause these environmental pressures is required in order to overcome these obstacles. International cooperation may be an important contributor to the progress and in particular provide access to financial, technological, scientific and human resource assistance.

  14. Population genetic structure and genetic diversity of Chinese pomfret at the coast of the East China Sea and the South China Sea.

    Science.gov (United States)

    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.

  15. Spatial and Temporal Distribution of Sea Surface Salinity in Coastal Waters of China Based on Aquarius

    International Nuclear Information System (INIS)

    Wang, Ying; Jiang, Hong; Zhang, Xiuying; Jin, Jiaxin

    2014-01-01

    Sea surface salinity (SSS) is a fundamental parameter for the study of global ocean dynamics, water cycle, and climate variability. Aquarius launched by NASA and the Space Agency of Argentina is a breakthrough which could achieve the remote sensing data of SSS. The present paper takes the coastal of China as study area, which is a representative area of ocean boundary and influenced by continental rivers (Yangtze River and Pearl River). After analyze the temporal and spatial variation of SSS in the coastal of China, the estuary area has obvious low salinity because the injected of freshwater from continent. Take the East China Sea (ECS) and South China Sea (SCS) as representative region to discuss the effect of freshwater to SSS. The salinity is almost equal in winter when the diluted water is inadequate in both rivers. However, an obvious decrease appeared in summer especial July in Yangtze River for abundance discharge inflow the ECS. This is a reasonable expression of Yangtze River discharge is remarkable influence the SSS in coastal area then Pearl River. Survey the distribution range of Yangtze River diluted water (SSS<31psu). The range is small in winter and expands to peak value in summer

  16. Screening of seaweeds in the East China Sea as potential bio-monitors of heavy metals.

    Science.gov (United States)

    Pan, Yaoru; Wernberg, Thomas; de Bettignies, Thibaut; Holmer, Marianne; Li, Ke; Wu, Jiaping; Lin, Fang; Yu, Yan; Xu, Jiang; Zhou, Chaosheng; Huang, Zhixing; Xiao, Xi

    2018-03-30

    Seaweeds are good bio-monitors of heavy metal pollution and have been included in European coastal monitoring programs. However, data for seaweed species in China are scarce or missing. In this study, we explored the potential of seaweeds as bio-monitor by screening the natural occurring seaweeds in the "Kingdom of seaweed and shellfish" at Dongtou Islands, the East China Sea. Totally, 12 seaweed species were collected from six sites, with richness following the sequence of Rhodophyta > Phaeophyta > Chlorophyta. The concentration of heavy metals (Cu, Cr, Ni, Zn, Pb, Cd, As) in the seaweeds was determined, and the bioaccumulation coefficient was calculated. A combination of four seaweeds, Pachydictyon coriaceum, Gelidium divaricatum, Sargassum thunbergii, and Pterocladiella capillacea, were proposed as bio-monitors due to their high bioaccumulation capabilities of specific heavy metals in the East China Sea and hence hinted the importance of using seaweed community for monitoring of pollution rather than single species. Our results provide first-hand data for the selection of bio-monitor species for heavy metals in the East China Sea and contribute to selection of cosmopolitan bio-monitor communities over geographical large area, which will benefit the establishment of monitoring programs for coastal heavy metal contamination.

  17. Assessment of the Joint Development Potential of Wave and Wind Energy in the South China Sea

    Directory of Open Access Journals (Sweden)

    Yong Wan

    2018-02-01

    Full Text Available The South China Sea is a major shipping hub between the West Pacific and Indian Oceans. In this region, the demand for energy is enormous, both for residents’ daily lives and for economic development. Wave energy and wind energy are two major clean and low-cost ocean sources of renewable energy. The reasonable development and utilization of these energy sources can provide a stable energy supply for coastal cities and remote islands of China. Before wave energy and wind energy development, however, we must assess the potential of each of these sources. Based on high-resolution and high-accuracy wave field data and wind field data obtained by ERA-Interim reanalysis for the recent 38-year period from 1979–2016, the joint development potential of wave energy and wind energy was assessed in detail for offshore and nearshore areas in the South China Sea. Based on potential installed capacity, the results revealed three promising areas for the joint development of nearshore wave energy and wind energy, including the Taiwan Strait, Luzon Strait and the sea southeast of the Indo-China Peninsula. For these three dominant areas (key stations, the directionality of wave energy and wind energy propagation were good in various seasons; the dominant wave conditions and the dominant wind conditions were the same, which is advantageous for the joint development of wave and wind energy. Existing well-known wave energy converters (WECs are not suitable for wave energy development in the areas of interest. Therefore, we must consider the distributions of wave conditions and develop more suitable WECs for these areas. The economic and environmental benefits of the joint development of wave and wind energy are high in these promising areas. The results described in this paper can provide references for the joint development of wave and wind energy in the South China Sea.

  18. Organochlorine pesticides in muscle of wild seabass and Chinese prawn from the Bohai Sea and Yellow Sea, China.

    Science.gov (United States)

    Shi, Shuangxin; Huang, Yeru; Zhang, Lifei; Zhang, Xiulan; Zhou, Li; Zhang, Ting; Dong, Liang

    2011-10-01

    Muscle samples from wild seabass and Chinese prawn collected from the Bohai Sea and the Yellow Sea, China were analyzed for 22 organochlorine pesticides. DDTs were the predominant contaminants in all samples. The concentration of DDTs in seabass was 247 μg kg(-1) wet wt (from 4.30 to 2,089 μg kg(-1) wet wt). Significantly, concentration of DDTs in seabass was much higher than that in prawn (6.51 μg kg(-1) wet wt). Very high concentrations of DDTs and high DDT/DDTs ratio were found in seabass samples from some locations, which imply there might be new inputs of DDT into the marine environment. © Springer Science+Business Media, LLC 2011

  19. The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

    Directory of Open Access Journals (Sweden)

    Tamar L Goulet

    Full Text Available Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont. We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c2 per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Qm, was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify

  20. Diversity and abundance of invertebrate epifaunal assemblages associated with gorgonians are driven by colony attributes

    KAUST Repository

    Curdia, Joao

    2015-03-20

    The present study aimed to explicitly quantify the link between the attributes of shallow-water gorgonian colonies (Octocorallia: Alcyonacea) and the ecological patterns of associated non-colonial epifaunal invertebrates. Based on multiple regression analysis, we tested the contribution of several attributes (colony height, width, and area, fractal dimension as a measure of colony complexity, lacunarity as a measure of the heterogeneity, and “colonial” epibiont cover) to abundance and taxonomic richness of associated assemblages. The results highlight the variation in the response of epifaunal assemblages to the gorgonian colony characteristics. The nature and intensity of the relationships were gorgonian species-dependent and varied from one taxonomic group to another. For both gorgonian species analyzed, the strongest predictor of species richness and abundance of the epifaunal assemblages was “colonial” epibiont cover, possibly due to a trophic effect (direct or indirect enhancement of food availability) combined with the surface available for colonization (species–area effect). Although structural complexity is usually indicated as the main driver for rich and abundant coral-associated assemblages, no significant relationship was observed between fractal dimension and the community descriptors; lacunarity, which reflects the sizes of the inter-branch spaces, was only linked to taxonomic richness in the assemblages associated with Leptogorgia lusitanica. The validity of the paradigm that structural complexity enhances biodiversity may be scale-dependent. In the case of gorgonians, the effect of complexity at the “garden” level may be more relevant than at the individual colony level. This reinforces the need for the conservation of gorgonian aggregation areas as a whole in order to preserve host diversity and size structure. © 2015 Springer-Verlag Berlin Heidelberg

  1. Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

    KAUST Repository

    Dias, I.M.

    2015-10-19

    The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal variability was linked to changes in environmental parameters, namely temperature, chlorophyll a and particulate organic carbon. Hence, temporal variability must be taken into account for the design of future biodiversity assessment studies, as different patterns may be observed depending on the sampling time. Associated epifaunal assemblages were consistently dominated by resident species (i.e. species present in all sampling periods) and a peak of rare species was observed in the transition from spring to summer following the increase of seawater temperature. Turnover was particularly high in the transition between the spring and summer periods. In both hosts, turnover was higher in the small sized colonies, which generally harboured less diverse and less abundant assemblages which also differed from those inhabiting larger size colonies. The high levels of diversity associated with gorgonian colonies highlights the need for the conservation of this priority habitat.

  2. Decline in the species richness contribution of Echinodermata to the macrobenthos in the shelf seas of China

    Science.gov (United States)

    Jin, Shaofei; Wang, Yongli; Xia, Jiangjiang; Xiao, Ning; Zhang, Junlong; Xiong, Zhe

    Echinoderms play crucial roles in the structure of marine macrobenthic communities. They are sensitive to excess absorption of CO2 by the ocean, which induces ocean acidification and ocean warming. In the shelf seas of China, the mean sea surface temperature has a faster warming rate compared with the mean rate of the global ocean, and the apparent decrease in pH is due not only to the increased CO2 absorption in seawater, but also eutrophication. However, little is known about the associated changes in the diversity of echinoderms and their roles in macrobenthic communities in the seas of China. In this study, we conducted a meta-analysis of 77 case studies in 51 papers to examine the changes in the contribution of echinoderm species richness to the macrobenthos in the shelf seas of China since the 1980s. The relative species richness (RSR) was considered as the metric to evaluate these changes. Trends analysis revealed significant declines in RSR in the shelf seas of China, the Yellow Sea, and the East China Sea from 1997 to 2009. Compared with the RSR before 1997, no significant changes in mean RSR were found after 1997, except in the Bohai Sea. In addition, relative change in the RSR of echinoderms and species richness of macrobenthos led to more changes (decrease or increase) in their respective biomasses. Our results imply that changes in species richness may alter the macrobenthic productivity of the marine benthic ecosystem.

  3. Notes on shark and ray types at the South China Sea Fisheries Research Institute (SCSFRI) in Guangzhou, China.

    Science.gov (United States)

    White, William T; Last, Peter R

    2013-01-01

    Most of the shark and ray type material at the South China Sea Fisheries Research Institute (SCSFRI) in Guangzhou, China was examined during a museum visit by the senior author in 2009. The status of the shark and ray species described from the South China Sea in the 1980s and deposited in this collection is discussed. Squalus acutirostris is considered a junior synonym of Squalus mitsukurii from the western North Pacific. Centrophorus ferrugineus is considered a junior synonym of Centrophorus squamosus. Centroscymnus macrops is confirmed as a junior synonym of Centroscymnus coelolepis. Scymnodon niger is confirmed as a junior synonym of Zameus squamulosus. Isistius labialis is considered a synonym of Isistius brasiliensis. Halaelurus immaculatus is confirmed as a valid species of the genus Bythaelurus. Urolophus marmoratus is considered a junior synonym of the widespread Plesiobatis daviesi. Springeria nanhaiensis is a questionable synonym of Sinobatis borneensis, following previous researchers. Springeria stenosoma is considered as questionably valid but with further investigation into generic placement required. The validity of species with SCSFRI type specimens not examined in this study are also briefly discussed.

  4. Historical change of mercury pollution in remote Yongle archipelago, South China Sea.

    Science.gov (United States)

    Liu, Xiaodong; Xu, Liqiang; Chen, Qianqian; Sun, Liguang; Wang, Yuhong; Yan, Hong; Liu, Yi; Luo, Yuhan; Huang, Jing

    2012-04-01

    We collected three ornithogenic coral sand sedimentary profiles from Jinyin Island, Jinqing Island and Guangjin Island of Yongle archipelago, South China Sea and reconstructed the deposition flux of anthropogenic Hg over the past 700 years in the study area. On the whole, the anthropogenic Hg flux is relatively low; it remained at a low level before the Industrial Revolution with a small peak at about 1450-1550 AD, which may record the enhanced metallurgy activity in Ming Dynasty of China. During the 20th century, the deposition flux of anthropogenic Hg increased rapidly, but two troughs occurred during the periods around 1940s and 1970s, corresponding to the economic depression caused by World War II, Civil War in China (1945-1949), and the Culture Revolution (1966-1976) in China. Since the 1970s the deposition flux of anthropogenic Hg has been persistently increasing, apparently the result of fast economic development in East and Southeast Asia countries around South China Sea. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Three new records of deep-water goniasterids (Echinodermata: Asteroidea: Goniasteridae) from China seas

    Science.gov (United States)

    Xiao, Ning; Liao, Yulin

    2013-09-01

    In this paper, three deep-water species of the family Goniasteridae, Ceramaster misakiensis (Goto, 1914), Nymphaster arthrocnemis Fisher, 1913 and Pontioceramus grandis Fisher, 1911, are recorded for the first time from Chinese waters based on collections deposited in the Marine Biological Museum, Chinese Academy of Sciences. The specimens examined were collected during the period 1956 to 1978 from the East China and South China Seas at depths of 184 to 472 m. Diagnosis, detailed figures, and the geographic distributions are provided. A revised list of Goniasteridae recorded from Chinese waters is proposed.

  6. WATER TEMPERATURE and other data from REEVES in the South China Sea on 1990-09-30 (NODC Accession 9000257)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession was collected in South China Sea (Nan Hai) from ship Reeves on September 30, 1990. The real time data of water temperature at varying...

  7. Hydrological, plankton and pigment observations in the South China Sea; 06 December 1971 to 28 December 1971 (NODC Accession 0000939)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report records the data collected during the cruise of the R.V. Jalanidhi in the South China Sea and the water around the Seribu Islands. The region of the...

  8. Advances in Marine Microbial Symbionts in the China Sea and Related Pharmaceutical Metabolites

    Directory of Open Access Journals (Sweden)

    Zhiyong Li

    2009-04-01

    Full Text Available Marine animals and plants such as sponges, sea squirts, corals, worms and algae host diverse and abundant symbiotic microorganisms. Marine microbial symbionts are possible the true producers or take part in the biosynthesis of some bioactive marine natural products isolated from the marine organism hosts. Investigation of the pharmaceutical metabolites may reveal the biosynthesis mechanisms of related natural products and solve the current problem of supply limitation in marine drug development. This paper reviews the advances in diversity revelation, biological activity and related pharmaceutical metabolites, and functional genes of marine microbial symbionts from the China Sea.

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

    Science.gov (United States)

    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

  10. Evaluation of Airborne LiDAR Bathymetric Parameters on the Northern South China Sea Based on MODIS Data

    Directory of Open Access Journals (Sweden)

    DING Kai

    2018-02-01

    Full Text Available In order to study the spatial distribution of maximum coastal zone mapping and imaging LiDAR(CZMILdetectable depth in the northern South China Sea,we firstly research the existing Kd(490 inversion algorithm in the northern South China Sea.The relationship between the diffuse attenuation coefficient Kd(490 and Kd(532 is established based on the optical profile data measured,and the relationship between the diffuse attenuation coefficient Kd(532 and the maximum CZMIL detectable depth is summarized.Then,using the remote measurement data of the Aqua-MODIS,we obtain the spatial distribution of diffuse attenuation coefficient at 532 nm in the northern South China Sea in January,June and October,2014.It shows that June is more suitable for bathymetry operation than in October and January.Finally,we obtain the spatial distribution of maximum CZMIL detectable depth in June in the northern South China Sea.The results show that the CZMIL detectable water depths in the northern South China Sea are about 0~71.18 m.The study provides a reference for the time selection and flight scheme of LiDAR bathymetry operation in the northern South China Sea.

  11. Trend and Variability of China Precipitation in Spring and Summer: Linkage to Sea Surface Temperatures

    Science.gov (United States)

    Yang, Fanglin; Lau, K.-M.

    2004-01-01

    Observational records in the past 50 years show an upward trend of boreal-summer precipitation over central eastern China and a downward trend over northern China. During boreal spring, the trend is upward over southeastern China and downward over central eastern China. This study explores the forcing mechanism of these trends in association with the global sea-surface temperature (SST) variations on the interannual and inter-decadal timescales. Results based on Singular Value Decomposition analyses (SVD) show that the interannual variability of China precipitation in boreal spring and summer can be well defined by two centers of actions for each season, which are co-varying with two interannual modes of SSTs. The first SVD modes of precipitation in spring and summer, which are centered in southeastern China and northern China, respectively, are linked to an ENSO-like mode of SSTs. The second SVD modes of precipitation in both seasons are confined to central eastern China, and are primarily linked to SST variations over the warm pool and Indian Ocean. Features of the anomalous 850-hPa winds and 700-Wa geopotential height corresponding to these modes support a physical mechanism that explains the causal links between the modal variations of precipitation and SSTs. On the decadal and longer timescale, similar causal links are found between the same modes of precipitation and SSTs, except for the case of springtime precipitation over central eastern China. For this case, while the interannual mode of precipitation is positively correlated with the interannual variations of SSTs over the warm pool and Indian Ocean; the inter-decadal mode is negatively correlated with a different SST mode, the North Pacific mode. The later is responsible for the observed downward trend of springtime precipitation over central eastern China. For all other cases, both the interannual and inter-decadal variations of precipitation can be explained by the same mode of SSTs. The upward trend

  12. Boron isotopic compositions in growing corals from the South China Sea

    Science.gov (United States)

    Xiao, Jun; Xiao, Yingkai; Jin, Zhangdong; Liu, Congqiang; He, Maoyong

    2013-01-01

    In order to determine incorporation of boron species, boron isotopic fractionation, and influence of trace elements on isotopic compositions of boron in corals (δ11Bcoral), concentrations of Mg, Sr, Na, B and δ11Bcoral in growing corals from the South China Sea were measured. Relative to seawater, Sr enriched while Mg depleted in corals in the South China Sea. Although the δ11Bcoral values were different from various species and were not closely correlated with the element concentrations in corals in the South China Sea, Mg(OH)2 existed in corals can result in high δ11Bcoral. Thus, it is necessary to examine the existence of Mg(OH)2 and to choose the same species when δ11Bcoral is used in the δ11B-pH proxy. Based on the measured δ11B values of corals and coexisting seawater as well as the seawater pH in the South China Sea, a new isotopic fractionation factor a4-3 between B(OH)4- and B(OH)3 was determined to be 0.979. Besides B(OH)4- into corals, our results showed that B(OH)3 may also be incorporated into corals with variable proportions. The incorporation of B(OH)3 into corals may challenge the hypothesis of δ11Bcoral = δ11B4, resulting in increasing uncertainty to the calculated seawater pH values to the δ11B-pH proxy. We suggested that a best-fit empirical equation between δ11B of bio-carbonates and seawater pH needs to be established by the precipitation experiments of inorganic carbonates or culture experiments of corals or foraminifera.

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

    Science.gov (United States)

    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

  14. Secondary metabolites from the South China Sea invertebrates: chemistry and biological activity.

    Science.gov (United States)

    Zhang, Wen; Guo, Yue-Wei; Gu, Yucheng

    2006-01-01

    The increasing demand for new lead compounds in the pharmaceutical and agrochemical industries has driven scientists to search for new sources of bioactive natural products. Marine invertebrates are a rich source of novel, bioactive secondary metabolites and they have attracted a great deal of attention from scientists in the fields of chemistry, pharmacology, ecology, and molecular biology. During the past 25 years, many complex and structurally unique secondary metabolites have been isolated from the invertebrates inhabiting the South China Sea. These metabolites are responsible for various bioactivities such as anti-tumor, anti-inflammation and antioxidant activities, and/or they act on the cardiovascular system. This review will focus on the marine natural product chemistry of invertebrates from the South China Sea, aiming to give the reader a brief view of the compounds isolated from these invertebrates, as well as their biological activities. The article covers the literature published during the period from the beginning of 1980 to the end of 2005, with 340 citations and 811 compounds from invertebrates from the South China Sea, including sponges, coelenterates, molluscs and echinoderms.

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

    Science.gov (United States)

    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.

  16. The Possible Physical Barrier and Coastal Dispersal Strategy for Japanese Grenadier Anchovy, Coilia nasus in the East China Sea and Yellow Sea: Evidence from AFLP Markers

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Han

    2015-02-01

    Full Text Available In order to ascertain the taxonomic status of the Ariake Sea population of Japanese grenadier anchovy, Coilia nasus, and assess the contemporary possible genetic barrier between the west and east coastal waters of the East China Sea, we used amplified fragment length polymorphism (AFLP markers to detect the genetic structure of C. nasus, in the East China Sea and Yellow Sea. Eighty-one individuals of C. nasus were collected from five locations and 12 individuals of Coilia mystus were sampled from the Yangtze River Estuary. A total of 371 loci were detected by five primer combinations, 310 of which were polymorphic (83.56%. Analysis of molecular variation (AMOVA and pairwise fixation index (FST revealed significant genetic differentiation among five samples, indicating limited gene flow among populations. The dendrogram for populations by neighbor-joining (NJ cluster analysis provided evidence of a clear relationship between genetic and geographic patterns, supporting significant genetic differentiation between China coastal populations and Ariake Sea populations. Compared to the genetic divergence between C. nasus and C. mystus, the level of genetic differentiation between China and the Ariake Sea populations of C. nasus is obvious below the species level, indicating isolated populations of C. nasus in the Ariake Sea. Isolation by distance analysis revealed that direct ocean distance with deep-water at the continental slope and high salinity between west and east coastal waters of the East China Sea served as major physical barrier to C. nasus, supporting the coastal dispersal pattern in this estuarine species, and rejecting offshore dispersal strategy.

  17. The Possible Physical Barrier and Coastal Dispersal Strategy for Japanese Grenadier Anchovy, Coilia nasus in the East China Sea and Yellow Sea: Evidence from AFLP Markers

    Science.gov (United States)

    Han, Zhi-Qiang; Han, Gang; Wang, Zhi-Yong; Gao, Tian-Xiang

    2015-01-01

    In order to ascertain the taxonomic status of the Ariake Sea population of Japanese grenadier anchovy, Coilia nasus, and assess the contemporary possible genetic barrier between the west and east coastal waters of the East China Sea, we used amplified fragment length polymorphism (AFLP) markers to detect the genetic structure of C. nasus, in the East China Sea and Yellow Sea. Eighty-one individuals of C. nasus were collected from five locations and 12 individuals of Coilia mystus were sampled from the Yangtze River Estuary. A total of 371 loci were detected by five primer combinations, 310 of which were polymorphic (83.56%). Analysis of molecular variation (AMOVA) and pairwise fixation index (FST) revealed significant genetic differentiation among five samples, indicating limited gene flow among populations. The dendrogram for populations by neighbor-joining (NJ) cluster analysis provided evidence of a clear relationship between genetic and geographic patterns, supporting significant genetic differentiation between China coastal populations and Ariake Sea populations. Compared to the genetic divergence between C. nasus and C. mystus, the level of genetic differentiation between China and the Ariake Sea populations of C. nasus is obvious below the species level, indicating isolated populations of C. nasus in the Ariake Sea. Isolation by distance analysis revealed that direct ocean distance with deep-water at the continental slope and high salinity between west and east coastal waters of the East China Sea served as major physical barrier to C. nasus, supporting the coastal dispersal pattern in this estuarine species, and rejecting offshore dispersal strategy. PMID:25654225

  18. The possible physical barrier and coastal dispersal strategy for Japanese grenadier anchovy, Coilia nasus in the East China Sea and Yellow Sea: evidence from AFLP markers.

    Science.gov (United States)

    Han, Zhi-Qiang; Han, Gang; Wang, Zhi-Yong; Gao, Tian-Xiang

    2015-02-03

    In order to ascertain the taxonomic status of the Ariake Sea population of Japanese grenadier anchovy, Coilia nasus, and assess the contemporary possible genetic barrier between the west and east coastal waters of the East China Sea, we used amplified fragment length polymorphism (AFLP) markers to detect the genetic structure of C. nasus, in the East China Sea and Yellow Sea. Eighty-one individuals of C. nasus were collected from five locations and 12 individuals of Coilia mystus were sampled from the Yangtze River Estuary. A total of 371 loci were detected by five primer combinations, 310 of which were polymorphic (83.56%). Analysis of molecular variation (AMOVA) and pairwise fixation index (FST) revealed significant genetic differentiation among five samples, indicating limited gene flow among populations. The dendrogram for populations by neighbor-joining (NJ) cluster analysis provided evidence of a clear relationship between genetic and geographic patterns, supporting significant genetic differentiation between China coastal populations and Ariake Sea populations. Compared to the genetic divergence between C. nasus and C. mystus, the level of genetic differentiation between China and the Ariake Sea populations of C. nasus is obvious below the species level, indicating isolated populations of C. nasus in the Ariake Sea. Isolation by distance analysis revealed that direct ocean distance with deep-water at the continental slope and high salinity between west and east coastal waters of the East China Sea served as major physical barrier to C. nasus, supporting the coastal dispersal pattern in this estuarine species, and rejecting offshore dispersal strategy.

  19. Organic walled dinoflagellate cysts from the Tarim Basin, western China: Implications for the retreat of the Paratethys Sea

    NARCIS (Netherlands)

    Grothe, A.; Houben, A.J.P.; Bosboom, R.E.; Dupont-Nivet, G.; Brinkhuis, H.

    2011-01-01

    Paleogene sediments of the Tarim basin in western China hold the easternmost extent of the Paratethys Sea, an epicontinental sea that covered a large part of Eurasia and probably extended to the Mediterranean Tethys in the west. The late Cretaceous and Paleogene sedimentary record of the

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

    Science.gov (United States)

    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.

  1. Sea level rise, surface warming, and the weakened buffering ability of South China Sea to strong typhoons in recent decades.

    Science.gov (United States)

    Sun, Jingru; Oey, Leo; Xu, F-H; Lin, Y-C

    2017-08-07

    Each year, a number of typhoons in the western North Pacific pass through the Luzon Strait into South China Sea (SCS). Although the storms remain above a warm open sea, the majority of them weaken due to atmospheric and oceanic environments unfavorable for typhoon intensification in SCS, which therefore serves as a natural buffer that shields the surrounding coasts from potentially more powerful storms. This study examines how this buffer has changed over inter-decadal and longer time scales. We show that the buffer weakens (i.e. greater potential for more powerful typhoons) in negative Pacific Decadal Oscillation (PDO) years, as well as with sea-level-rise and surface warming, caused primarily by the deepening of the ocean's 26 °C isotherm Z 26 . A new Intensity Change Index is proposed to describe the typhoon intensity change as a function of Z 26 and other environmental variables. In SCS, the new index accounts for as high as 75% of the total variance of typhoon intensity change.

  2. GEM in the marine atmosphere and air-sea exchange of Hg during late autumn and winter cruise campaigns over the marginal seas of China

    Science.gov (United States)

    Wang, Yan; Liu, Ruhai; Li, Yanping; Cui, Xueqing; Zhou, Jianping; Liu, Shixuan; Zhang, Yuqing

    2017-07-01

    East Asia is one of the primary sources of atmospheric gaseous elemental mercury (GEM) among the world. In this study, GEM concentrations were measured during two cruises in late autumn and winter of 2012 and 2013 which passed through the marginal seas of China. The results show that the mean GEM concentration was 1.65 ng/m3 from the South China Sea to the Yellow Sea during the 2012 cruise. While the mean GEM concentration was 2.38 ng/m3 in the South Yellow Sea, and 1.75 ng/m3 in the North Yellow and Bohai Seas during the 2013 cruise. High GEM contents were detected when the steering wind was offshore. There is a significant positive relationship between GEM and air temperature for these two cruises. Low GEM content was presented when the cold northerly monsoon prevailed while air masses mainly came from the clean northern oceanic region. Dissolved gaseous mercury (DGM) concentration in the surface water of the south Yellow and Bohai seas were 74.4 ± 28 pg/L. DGM concentrations were correlated with water temperature (r = 0.244, p polluted air and low wind speed. High flux values were caused by the northerly monsoon which carried remote clean air to the sea, with large wind speeds. The northerly monsoon is an important factor affecting the GEM transport offshore to marginal sea and the cycle of mercury in the sea in late autumn and winter.

  3. Analysis and Prediction of Changes in Coastline Morphology in the Bohai Sea, China, Using Remote Sensing

    Directory of Open Access Journals (Sweden)

    Ying Fu

    2017-05-01

    Full Text Available Coastline change reflects the dynamics of natural processes and human activity, and influences the ecology and environment of the coastal strip. This study researched the change in coastline and sea area of the Bohai Sea, China, over a 30-year period using Landsat TM and OLI remote sensing data. The total change in coastline length, sea area, and the centroid of the sea surface were quantified. Variations in the coastline morphology were measured using four shape indexes: fractal dimension, compact ratio, circularity, and square degree. Equations describing fit of the shape index, coastline length, and marine area were built. Then the marine area 10 years later was predicted using the model that had the highest prediction accuracy. The results showed that the highest prediction accuracy for the coastline length was obtained using a compound function. When a cubic function was used to predict the compact ratio, then the highest prediction accuracy was obtained using this compact ratio and a quadratic function to predict sea area. This study can provide theoretical support for the coastal development planning and ecological environment protection around the Bohai Sea.

  4. Realized niches explain spatial gradients in seasonal abundance of phytoplankton groups in the South China Sea

    Science.gov (United States)

    Xiao, Wupeng; Wang, Lei; Laws, Edward; Xie, Yuyuan; Chen, Jixin; Liu, Xin; Chen, Bingzhang; Huang, Bangqin

    2018-03-01

    A basic albeit elusive goal of ocean science is to predict the structure of biological communities from the multitude of environmental conditions they experience. Estimates of the realized niche-based traits (realized traits) of phytoplankton species or functional groups in temperate seas have shown that response traits can help reveal the mechanisms responsible for structuring phytoplankton communities, but such approaches have not been tested in tropical and subtropical marginal seas. Here, we used decadal-scale studies of pigment-based phytoplankton groups and environmental conditions in the South China Sea to test whether realized traits could explain the biogeographic patterns of phytoplankton variability. We estimated the mean and breadth of the phytoplankton realized niches based on responses of the group-specific phytoplankton composition to key environmental factors, and we showed that variations of major phytoplankton groups in this system can be explained by different adaptive trade-offs to constraints imposed by temperature, irradiance, and nutrient concentrations. Differences in the patterns of trade-offs clearly separated the dominant groups from one another and generated four sets of realized traits that mirrored the observed biogeographic distribution patterns. The phytoplankton realized niches and their associated traits that we characterized in the present study could help to predict responses of phytoplankton to changes in environmental conditions in the South China Sea and could be incorporated into global biogeochemical models to anticipate shifts in community structure under future climate scenarios.

  5. Quaternary palaeoceanographic changes in the northern South China Sea (ODP Site 1146): radiolarian evidence

    Science.gov (United States)

    Wang, Rujian; Clemens, Steven; Huang, Baoqi; Chen, Muhong

    2003-12-01

    The abundance and accumulation rates of siliceous microfossils in the northern South China Sea, including radiolarians, diatoms and sponge spicules, increased during most glacial intervals within the past 1100 kyr. Similar trends are observed in the index of thermocline surface radiolarians (TSR), diatom accumulation rates (DAR), charcoal accumulation rates (CAR) and the abundance of radiolarian species Cycladophora davisiana davisiana. Decreasing sea-surface temperature accompanied by increased seasonality since 900 ka is indicated by a decline in the tropical radiolarian assemblage, including Tetrapyle octacantha and Octopyle stenozona, and by an increase in the subtropical assemblage, including Pterocorys zancleus, Peromelissa phalacra and Ommatartuts tetrathalamus tetrathalamus. Rapid increases at about 800 to 700 ka of siliceous microfossils, charcoal, subsurface and intermediate radiolarians, as well as the TSR index and the DAR, imply a fundamental shift in climate and a shoaling thermocline. Although these fundamental changes in the silicious fauna and flora of the South China Sea take place within the context of a developing 100-kyr cycle, they do not change in step with changing sea-level as indicated by marine 18O. This is most clearly illustrated by the step-like increase in silica accumulation (radiolaria, diatoms and sponge spicules) at 680 ka. Rather, these fundamental changes probably reflect intensified surface productivity associated with enhanced East Asian winter-monsoon circulation. Copyright

  6. Spatial diversity of bacterioplankton communities in surface water of northern South China Sea.

    Directory of Open Access Journals (Sweden)

    Jialin Li

    Full Text Available 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.

  7. Variation of phytoplankton community structure from the Pearl River estuary to South China Sea.

    Science.gov (United States)

    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 phytoplankton diversity was highly positively affected by salinity (P phytoplankton distribution and biomass of the study area. Further research is necessary to reveal the influence mechanism of environmental factors on the phytoplankton.

  8. Four newly recorded free-living marine nematodes (Comesomatidae) from the East China Sea

    Science.gov (United States)

    Hua, Er; Zhang, Zhinan

    2007-01-01

    Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gubernaculum median piece. The characters of S. breviseta agree quite well with the European original descriptions and only differ in the male amphid turns (5.5 vs. 4.0 turns) and unmodified preanal supplements (5-7 vs. 6). S. pulchra can be recognized by amphid 2.75 turns, irregularly arranged lateral dots, and the first three supplements anterior to the anus, which are more widely spaced than the following ones. The excretory system of S. breviseta and S. pulchra shows sexual dimorphism. S. celtica is defined by amphids 2.00-2.25 turns, weakly developed pharyngeal bulb, curved apophyses and 12-13 conspicuous supplements. C. deltensis is characterized by amphids 4.75 turns, ovate pharyngeal posterior bulb, sperm dimorphism, 7 thin preanal supplements, and long tail cylindrical portion (50%-53% of tail length). All the three Sabatieria species are for the first time recorded in Chinese waters. C. deltensis was originally isolated from the Bohai Sea and Yellow Sea and newly recorded in the East China Sea.

  9. Nutrients, meteorological, and physical data collected from PUSAN 851 and other platforms using bottle casts in the East China Sea and Yellow Sea from 12 January 1905 to 14 December 1990 (NODC Accession 9200148)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nutrients, physical, and meteorological data were collected using bottle casts in the East China Sea and Yellow Sea by PUSAN 851 and other platforms. Data were...

  10. HELIUM, PARTICULATE ORGANIC CARBON and other data from HEIYO, KAIYO and other platforms in the NW Pacific, Philippine Sea and East China Sea from 1939-08-17 to 1988-09-27 (NODC Accession 9000197)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A tape containing part of the annual exchange of chemical data from the Japan Oceanographic Data Center collected from East China Sea (Tung Hai), Philippine Sea, NW...

  11. Identification of the Eight-Membered Heterocycles Hicksoanes A-C from the Gorgonian Subergorgia hicksoni

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Hanuš, L. O.; Dembitsky, V. M.; Sigler, Karel

    2008-01-01

    Roč. 2008, č. 7 (2008), s. 1265-1270 ISSN 1434-193X R&D Projects: GA MŠk 1P05OC073 Institutional research plan: CEZ:AV0Z50200510 Keywords : gorgonians * nitrogen heterocycles * natural products Subject RIV: EE - Microbiology, Virology Impact factor: 3.016, year: 2008

  12. Development of Cryopreservation Techniques for Gorgonian (Junceella juncea Oocytes through Vitrification.

    Directory of Open Access Journals (Sweden)

    Sujune Tsai

    Full Text Available Gorgonian corals are slowly declining due to human interaction and environmental impacts. Cryopreservation of gorgonian corals is an ex-situ method of conservation, ensuring future reproduction. The present study assessed the vitrification properties of cryoprotectant (CPT mixtures using the cryotop, cryoloop and open pulled straw (OPS cryopereservation methods prior to experimentation on gorgonian (Junceella juncea oocytes. Investigations of the equilibration and vitrification solutions' (ES and VS effect on oocytes throughout different incubation periods were conducted. The cryotop method was found to be the most successful in ensuring vitrification. The most favourable VS was composed of propylene glycol (PG, ethylene glycol (EG and methanol with concentrations of 3.5 M, 1.5 M and 2 M respectively. Experiments were performed using the cryotop method to cryopreserve Junceella juncea oocytes using VS2, the solution had the least impact on oocytes at 5°C rather than at 26°C. The success of the vitrification procedures was determined by adenosine triphosphate (ATP levels in cooled-thaw oocytes and the highest viability obtained from the present study was 76.6 ± 6.2%. This study provides information regarding gorgonian corals' tolerance and viability throughout vitrification to further advance the vitrification protocol on whip corals.

  13. Environment and security in the South China Sea region : the role of experts, non-governmental actors and governments in regime building processes

    OpenAIRE

    Næss, Tom

    1999-01-01

    Background: The Spratly islands in the South China Sea are today the focal point of a territorial dispute that represents a serious threat to the regional security in Southeast Asia. Six governments - China, Vietnam, Taiwan, the Philippines, Malaysia and Brunei - have laid claims to all or some of the more than 230 islets, reefs and shoals in the Spratly area. The Peoples Republic of China (PRC) is a key player in the South China Sea conflict. However, the South China Sea is not jus...

  14. Tiny sea anemone from the Lower Cambrian of China.

    Directory of Open Access Journals (Sweden)

    Jian Han

    Full Text Available BACKGROUND: Abundant fossils from the Ediacaran and Cambrian showing cnidarian grade grossly suggest that cnidarian diversification occurred earlier than that of other eumetazoans. However, fossils of possible soft-bodied polyps are scanty and modern corals are dated back only to the Middle Triassic, although molecular phylogenetic results support the idea that anthozoans represent the first major branch of the Cnidaria. Because of difficulties in taxonomic assignments owing to imperfect preservation of fossil cnidarian candidates, little is known about forms ancestral to those of living groups. METHODS AND FINDINGS: We have analyzed the soft-bodied polypoid microfossils Eolympia pediculata gen. et sp. nov. from the lowest Cambrian Kuanchuanpu Formation in southern China by scanning electron microscopy and computer-aided microtomography after isolating fossils from sedimentary rocks by acetic acid maceration. The fossils, about a half mm in body size, are preserved with 18 mesenteries including directives bilaterally arranged, 18 tentacles and a stalk-like pedicle. The pedicle suggests a sexual life cycle, while asexual reproduction by transverse fission also is inferred by circumferential grooves on the body column. CONCLUSIONS: The features found in the present fossils fall within the morphological spectrum of modern Hexacorallia excluding Ceriantharia, and thus Eolympia pediculata could be a stem member for this group. The fossils also demonstrate that basic features characterizing modern hexacorallians such as bilateral symmetry and the reproductive system have deep roots in the Early Cambrian.

  15. Phytoplankton pigment patterns and community composition in the northern South China Sea during winter

    Science.gov (United States)

    Zhai, Hongchang; Ning, Xiuren; Tang, Xuexi; Hao, Qiang; Le, Fengfeng; Qiao, Jing

    2011-03-01

    Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recognized four different vertical distribution patterns of pigments: chlorophyll a (Chi a)-like type, divinyl chlorophyll a (DV Chi a) type, even distribution type, and surface type. The average value of ratios of accessory photo-protective pigments (APP) to accessory photo-synthetic pigments was 0.89±0.63 in the upper 50 m and 0.16±0.06 below 50 m depth. With increasing depth, APP decreased and photo-synthetically active radiation was attenuated. There was an obvious succession in the phytoplankton community from inshore to the open sea. Diatoms were dominant in the inshore region, while pelagophytes, Prochlorococcus, cyanobacteria and prymnesiophytes were dominant in the open sea. The vertical distribution of phytoplankton also differed greatly from inshore to the open sea. In the coastal and shelf region, diatoms were important components in the whole water column. Cyanobacteria also had a high abundance at the Subsurface Chlorophyll a Maxima (SCM) in the shelf region. In the slope and open sea, Prochlorococcus and cyanobacteria were important groups above the SCM, while pelagophytes dominated below the SCM.

  16. Carbon Cycle in South China Sea: Flux, Controls and Global Implications

    Science.gov (United States)

    Dai, M.; Cao, Z.; Yang, W.; Guo, X.; Yin, Z.; Gan, J.

    2016-12-01

    The contemporary coastal ocean is generally seen as a significant CO2 sink of 0.2-0.4 Pg C/yr at the global scale. However, mechanistic understanding of the coastal ocean carbon cycle remains limited, leading to the unanswered question of why some coastal systems are sources while others are sinks of atmospheric CO2. As the largest marginal sea of Northern Pacific, the South China Sea (SCS) is a mini-ocean with wide shelves in both its southern and northern parts. Its northern shelf, which receives significant land inputs from the Pearl River, a world major river, can be categorized as a River-Dominated Margin (RioMar) during peak discharges, and is characterized as a CO2 sink to the atmosphere. The SCS basin is identified as an Ocean-Dominated Margin (OceMar) and a CO2 source. OceMar is characterized by exchange with the open ocean via a two-dimensional (at least) process, i.e., the horizontal intrusion of open ocean water and subsequent vertical mixing and upwelling. Depending on the different ratios of dissolved inorganic carbon (DIC) and nutrients from the source waters into the continental margins, the relative consumption or removal bwtween DIC and nutrients, when being transported into the euphotic zones where biogeochemical processes take over, determines the CO2 fluxes. Thus, excess DIC relative to nutrients existing in the upper layer will lead to CO2 degassing. The CO2 fluxes in both RioMars and OceMars can be quantified using a semi-analytical diagnostic approach by coupling the physical dynamics and biogeochemical processes. We extended our mechanistic studies in the SCS to other OceMars including the Caribbean Sea, the Arabian Sea, and the upwelling system off the Oregon-California coast, and RioMars including the East China Sea and Amazon River plume to demonstrate the global implications of our SCS carbon studies.

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

    Science.gov (United States)

    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

  18. Unusual distribution of floating seaweeds in the East China Sea in the early spring of 2012.

    Science.gov (United States)

    Komatsu, Teruhisa; Mizuno, Shizuha; Natheer, Alabsi; Kantachumpoo, Attachai; Tanaka, Kiyoshi; Morimoto, Akihiko; Hsiao, Sheng-Tai; Rothäusler, Eva A; Shishidou, Hirotoshi; Aoki, Masakazu; Ajisaka, Tetsuro

    2014-01-01

    Floating seaweeds play important ecological roles in offshore waters. Recently, large amounts of rafting seaweed have been observed in the East China Sea. In early spring, juveniles of commercially important fish such as yellowtail accompany these seaweed rafts. Because the spatial distributions of seaweed rafts in the spring are poorly understood, research cruises were undertaken to investigate them in 2010, 2011, and 2012. Floating seaweed samples collected from the East China Sea during the three surveys contained only Sargassum horneri . In 2010 and 2011, seaweed rafts were distributed only in the continental shelf and the Kuroshio Front because they had become trapped in the convergence zone of the Kuroshio Front. However, in 2012, seaweed was also distributed in the Kuroshio Current and its outer waters, and massive strandings of seaweed rafts were observed on the northern coast of Taiwan and on Tarama Island in the Ryukyu Archipelago. Environmental data (wind, currents, and sea surface height) were compared among the surveys of 2010, 2011, and 2012. Two factors are speculated to have caused the unusual distribution in 2012. First, a continuous strong north wind produced an Ekman drift current that transported seaweed southwestward to the continental shelf and eventually stranded seaweed rafts on the coast of Taiwan. Second, an anticyclonic eddy covering northeast Taiwan and the Kuroshio Current west of Taiwan generated a geostrophic current that crossed the Kuroshio Current and transported the rafts to the Kuroshio Current and its outer waters. Such unusual seaweed distributions may influence the distribution of fauna accompanying the rafts.

  19. Spectral Interpretation of Wave-vortex Duality in Northern South China Sea

    Science.gov (United States)

    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.

  20. [Diversity of culturable actinomycetes in sea deposit of Tiger beach at Bohai Bay, Dalian, China].

    Science.gov (United States)

    Lin, Ling; Tan, Yi; Chen, Feifei; Zhou, Hongxia; Wang, Yiguang; He, Weiqing; Wang, Yong

    2011-02-01

    To study the diversity of culturable actinomycetes isolated from the sea deposit of Tiger beach at Bohai bay, Dalian, China. By using five different media strains we isolated actinomycetes strains from the sea deposit of Tiger beach at Bohai bay, Dalian, China. Partial 16S rRNA sequences were carried out to characterize the diversity of culturable actinomycetes. A total of 1215 colonies with phenotypical actinomycetes were isolated, of which 271 were classified by 16S rRNA phylogenetic analysis. The data showed that 251 strains were homologous with Actinobacteria (92.26% ) including 15 genera of 11 families, and the remaining 20 strains were possible members of the phylum Firmicutes and Proteobacteria. There were 7 strains (3-166, 3-117, 3-435, 5-186-2, 5-9, 5-171, 3-134) to be preliminarily identified as unreported species. A high diversity of culturable actinomycets both in terms of the number of species and phylogenetic composition was presented from the sea deposit of Tiger beach in Bohai bay.

  1. Diversity and Biosynthetic Potential of Culturable Actinomycetes Associated with Marine Sponges in the China Seas

    Science.gov (United States)

    Xi, Lijun; Ruan, Jisheng; Huang, Ying

    2012-01-01

    The diversity and secondary metabolite potential of culturable actinomycetes associated with eight different marine sponges collected from the South China Sea and the Yellow sea were investigated. A total of 327 strains were isolated and 108 representative isolates were selected for phylogenetic analysis. Ten families and 13 genera of Actinomycetales were detected, among which five genera represent first records isolated from marine sponges. Oligotrophic medium M5 (water agar) proved to be efficient for selective isolation, and “Micromonospora–Streptomyces” was proposed as the major distribution group of sponge-associated actinomycetes from the China Seas. Ten isolates are likely to represent novel species. Sponge Hymeniacidon perleve was found to contain the highest genus diversity (seven genera) of actinomycetes. Housekeeping gene phylogenetic analyses of the isolates indicated one ubiquitous Micromonospora species, one unique Streptomyces species and one unique Verrucosispora phylogroup. Of the isolates, 27.5% displayed antimicrobial activity, and 91% contained polyketide synthase and/or nonribosomal peptide synthetase genes, indicating that these isolates had a high potential to produce secondary metabolites. The isolates from sponge Axinella sp. contained the highest presence of both antimicrobial activity and NRPS genes, while those from isolation medium DNBA showed the highest presence of antimicrobial activity and PKS I genes. PMID:22754340

  2. Overlooked habitat of a vulnerable gorgonian revealed in the Mediterranean and Eastern Atlantic by ecological niche modelling.

    Science.gov (United States)

    Boavida, Joana; Assis, Jorge; Silva, Inga; Serrão, Ester A

    2016-11-14

    Factors shaping the distribution of mesophotic octocorals (30-200 m depth) remain poorly understood, potentially leaving overlooked coral areas, particularly near their bathymetric and geographic distributional limits. Yet, detailed knowledge about habitat requirements is crucial for conservation of sensitive gorgonians. Here we use Ecological Niche Modelling (ENM) relating thirteen environmental predictors and a highly comprehensive presence dataset, enhanced by SCUBA diving surveys, to investigate the suitable habitat of an important structuring species, Paramuricea clavata, throughout its distribution (Mediterranean and adjacent Atlantic). Models showed that temperature (11.5-25.5 °C) and slope are the most important predictors carving the niche of P. clavata. Prediction throughout the full distribution (TSS 0.9) included known locations of P. clavata alongside with previously unknown or unreported sites along the coast of Portugal and Africa, including seamounts. These predictions increase the understanding of the potential distribution for the northern Mediterranean and indicate suitable hard bottom areas down to >150 m depth. Poorly sampled habitats with predicted presence along Algeria, Alboran Sea and adjacent Atlantic coasts encourage further investigation. We propose that surveys of target areas from the predicted distribution map, together with local expert knowledge, may lead to discoveries of new P. clavata sites and identify priority conservation areas.

  3. Comparison of two Centennial-scale Sea Surface Temperature Datasets in the Regional Climate Change Studies of the China Seas

    Science.gov (United States)

    Qingyuan, Wang; Yanan, Wang; Yiwei, Liu

    2017-08-01

    Two widely used sea surface temperature (SST) datasets are compared in this article. We examine characteristics in the climate variability of SST in the China Seas.Two series yielded almost the same warming trend for 1890-2013 (0.7-0.8°C/100 years). However, HadISST1 series shows much stronger warming trends during 1961-2013 and 1981-2013 than that of COBE SST2 series. The disagreement between data sets was marked after 1981. For the hiatus period 1998-2013, the cooling trends of HadISST1 series is much lower than that of COBE SST2. These differences between the two datasets are possibly caused by the different observations which are incorporated to fill with data-sparse regions since 1982. Those findings illustrate that there are some uncertainties in the estimate of SST warming patterns in certain regions. The results also indicate that the temporal and spatial deficiency of observed data is still the biggest handicap for analyzing multi-scale SST characteristics in regional area.

  4. Spatial contrast in phytoplankton, bacteria and microzooplankton grazing between the eutrophic Yellow Sea and the oligotrophic South China Sea

    Science.gov (United States)

    Zhang, Yafeng; Wang, Xutao; Yin, Kedong

    2017-06-01

    Three cruises were conducted to investigate the distributions of nutrients, chlorophyll a (Chl-a), new and regenerated primary production, bacterial abundance and production, and microzooplankton grazing rates in the Yellow Sea (YS) and the South China Sea (SCS) during March and May. As the water column moved from low to high temperature, weak to strong stratification and high to low nutrients from the YS to the SCS, Chl-a, primary production and bacterial biomass decreased. In contrast, bacterial production, microzooplankton grazing and size preference increased from the YS to the SCS. The increasing grazing activity and decreasing f-ratio from the YS to the SCS suggest roles of regenerated nutrients in the supporting the community increased and more bacteria played important roles in the carbon flow in the oligotrophic SCS than in the eutrophic YS. These variabilities force the classical food chain dominated community in the eutrophic waters into the microbial loop, which is dominant in oligotrophic waters. As nutrients decrease, temperature and grazing activity increase from the YS to the SCS. The increasing ratio of integrated bacterial production to integrated primary production indicates that communities change from autotrophy to heterotrophy and waters change from a carbon sink to a carbon source.

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

    Science.gov (United States)

    2012-01-01

    bloody Japanese takeovers of the Shandong pen- insula and Manchuria in the heart of China. This was all in addition to the humiliations forced on...Economic Council summit in Hawaii in November 2011 – is the currency of the realm in Asia. In 2011, China’s trade with ASEAN countries was topping...well emerge to fill the vacuum. Although U.S. leadership at the November 2011 Asia-Pacific Economic Cooperation summit in | 25 Hawaii emphasized the

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Highlights: • A large-scale investigation of MeHg in 46 species of marine wild fish from South China Sea. • Log 10 MeHg 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 species. • Biomagnification of MeHg was site-specific. -- Abstract: 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. Log 10 MeHg 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 Log 10 (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

  7. Temporal and spatial diversity of bacterial communities in coastal waters of the South china sea.

    Directory of Open Access Journals (Sweden)

    Jikun Du

    Full Text Available 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.

  8. Distributions and sea-to-air fluxes of chloroform, trichloroethylene, tetrachloroethylene, chlorodibromomethane and bromoform in the Yellow Sea and the East China Sea during spring

    International Nuclear Information System (INIS)

    He, Zhen; Yang, Gui-Peng; Lu, Xiao-Lan; Zhang, Hong-Hai

    2013-01-01

    Halocarbons including chloroform (CHCl 3 ), trichloroethylene (C 2 HCl 3 ), tetrachloroethylene (C 2 Cl 4 ), chlorodibromomethane (CHBr 2 Cl) and bromoform (CHBr 3 ) were measured in the Yellow Sea (YS) and the East China Sea (ECS) during spring 2011. The influences of chlorophyll a, salinity and nutrients on the distributions of these gases were examined. Elevated levels of these gases in the coastal waters were attributed to anthropogenic inputs and biological release by phytoplankton. The vertical distributions of these gases in the water column were controlled by different source strengths and water masses. Using atmospheric concentrations measured in spring 2012 and seawater concentrations obtained from this study, the sea-to-air fluxes of these gases were estimated. Our results showed that the emissions of C 2 HCl 3 , C 2 Cl 4, CHBr 2 Cl, and CHBr 3 from the study area could account for 16.5%, 10.5%, 14.6%, and 3.5% of global oceanic emissions, respectively, indicating that the coastal shelf may contribute significantly to the global oceanic emissions of these gases. -- Highlights: ► Distributions of the VHCs were studied in the YS and the ECS. ► Elevated levels of VHCs were related to terrestrial input from the Yangtze River. ► Biogenic production from diatoms was an important source of the VHCs. ► Shelf seas could significantly contribute to the global oceanic VHCs emission. -- The elevated levels of the volatile halocarbons in the coastal waters were attributed to anthropogenic inputs and biological release by phytoplankton (e.g., diatoms)

  9. Comparative analysis of environmental carrying capacity of the Bohai Sea Rim area in China.

    Science.gov (United States)

    Lin, Lu; Liu, Yi; Chen, Jining; Zhang, Tianzhu; Zeng, Siyu

    2011-11-01

    Environmental carrying capacity is an essential metric for measuring regional sustainability. Although the term "carrying capacity" has been applied for over a century, the concept definition, quantitative methods and comprehensive evaluation remain arguable. This study analyzed the carrying capacity of four environmental elements, including water resources, air, surface water and offshore sea, and integrated them into a comprehensive index to represent overall regional profiles of resources and environment. The method was then applied to thirteen municipalities in the Bohai Sea Rim area, one of the most rapidly developing regions in transition China. The results show that the comprehensive environmental carrying capacity of the municipalities in the south sub-region were largest in 2007, while that of the west municipalities were lowest. The regional economic development exceeded the overall environmental carrying capacity by 36% and the west sub-region area deserves overwhelming attention for future industrial allocation.

  10. Climate Change and China as a Global Emerging Regulatory Sea Power in the Arctic Ocean

    DEFF Research Database (Denmark)

    Cassotta Pertoldi-Bianchi, Sandra; Hossain, Kamrul; Ren, Jingzheng

    2015-01-01

    on the Law of the Sea (UNCLOS) and the Arctic Council (AC) are taken into consideration under climate change effects, to assess how global legal frameworks and institutions can deal with China’s strategy in the Arctic Ocean. China’s is moving away from its role as “humble power” to one of “informal...... between states and can result in tensions, even military ones. This article investigates through a political and legal analysis the role of China as an emerging regulatory sea power in the Arctic Ocean given its assertive “energy hungry country behaviour” in the Arctic Ocean. The United Nations Convention...... be considered as a variable for Arctic security as there are no sufficient legal and policy objective elements to adduct that it constitutes a threat to Artic ocean security....

  11. Four new 6-oxy purine alkaloids from the South China Sea sponge, Haliclona cymaeformis

    Science.gov (United States)

    Chen, Min; Wu, Xudong; Shen, Nanxing; Wang, Changyun

    2017-12-01

    In this study, the chemical analysis of the marine sponge spieces, Haliclona cymaeformis, collected from the South China Sea was carried out, Two pairs of regioisomers of alkyl substitutional 6-oxy purine alkaloids ( 1a/ 1b and 2a/ 2b) were isolated. All of them possess two structural moieties, a 6-oxy purine nucleus and a pentan-2-one or hexan-2-one alkyl chain. Among them, 1a and 2a are the major N-9-substitutional regioisomers, and 1b and 2b are the minor N-7-substitutional regioisomers.

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

    Science.gov (United States)

    2017-03-20

    codified in writing and ratified by all states. An impetus for UNCLOS was the growing number of maritime claims which arose out of CIL. The Third...Overcome South China Sea Disputes,” Asian Social Science 11, no. 18 (June 2015): 274-278; Michael Sheng-Ti Gau, “The U-Shaped Line and a Categorization of...Share Power (Collingwood VIC, Australia : Black Inc., 2012) 98-112. 58 Patrick, “World Order,” 9. 59 Idib. Quoting Henry Kissinger, World Restored

  13. Tides and their dynamics over the Sunda Shelf of the southern South China Sea

    DEFF Research Database (Denmark)

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

    2016-01-01

    State University TOPEX/Poseidon Global Inverse Solution (TPXO7.2) at the open boundaries. The results are validated against observed tidal amplitudes and phases at 19 locations. Results show that the mean average power energy spectrum (in unit m2/s/cph) for diurnal tides at the southern end of the East...... that diurnal tides are dominant along the East Coast of Peninsular Malaysia while both diurnal and semidiurnal tides dominate almost equally in coastal East Malaysia. Furthermore, the diurnal tidal energy flux is found to be 60% greater than that of the semidiurnal tides in the southern South China Sea. Based...

  14. Chemical constituents of soft coral Sarcophyton infundibuliforme from the South China Sea

    KAUST Repository

    Wang, Chang Yun

    2011-08-01

    Chemical investigation on soft coral Sarcophyton infundibuliforme collected from the South China Sea led to the isolation and identification of 14 secondary metabolites, including ten cembrene diterpenoids (1-10), one α-tocopheryl quinone derivative (11), one prostaglandin (12), one lipid (13) and one carotinoid (14). Their structures were determined by extensive analysis of their spectroscopic data. All of these metabolites were isolated from this species for the first time. Diterpenoids 1, 2, 7 and 10 showed potent antifouling activity against the larval settlement of barnacle Balanus amphitrite. © 2011 Elsevier Ltd.

  15. Annual and interannual variability of scatterometer ocean surface wind over the South China Sea

    DEFF Research Database (Denmark)

    Zhang, GS; Xu, Q.; Gong, Z.

    2014-01-01

    To investigate the annual and interannual variability of ocean surface wind over the South China Sea (SCS), the vector empirical orthogonal function (VEOF) method and the Hilbert-Huang transform (HHT) method were employed to analyze a set of combined satellite scatterometer wind data during...... the period from December 1992 to October 2009. The merged wind data were generated from European Remote Sensing Satellite (ERS)-1/2 Scatterometer, NASA Scatterometer (NSCAT) and NASA's Quick Scatterometer (QuikSCAT) wind products. The first VEOF mode corresponds to a winter-summer mode which accounts for 87...

  16. Empirical prediction of the onset dates of South China Sea summer monsoon

    Science.gov (United States)

    Zhu, Zhiwei; Li, Tim

    2017-03-01

    The onset of South China Sea summer monsoon (SCSSM) signifies the commencement of the wet season over East Asia. Predicting the SCSSM onset date is of significant importance. In this study, we establish two different statistical models, namely the physical-empirical model (PEM) and the spatial-temporal projection model (STPM) to predict the SCSSM onset. The PEM is constructed from the seasonal prediction perspective. Observational diagnoses reveal that the early onset of the SCSSM is preceded by (a) a warming tendency in middle and lower troposphere (850-500 hPa) over central Siberia from January to March, (b) a La Niña-like zonal dipole sea surface temperature pattern over the tropical Pacific in March, and (c) a dipole sea level pressure pattern with negative center in subtropics and positive center over high latitude of Southern Hemisphere in January. The PEM built on these predictors achieves a cross-validated reforecast temporal correlation coefficient (TCC) skill of 0.84 for the period of 1979-2004, and an independent forecast TCC skill of 0.72 for the period 2005-2014. The STPM is built on the extended-range forecast perspective. Pentad data are used to predict a zonal wind index over the South China Sea region. Similar to PEM, the STPM is constructed using 1979-2004 data. Based on the forecasted zonal wind index, the independent forecast of the SCSSM onset dates achieves a TCC skill of 0.90 for 2005-2014. The STPM provides more detailed information for the intraseasonal evolution during the period of the SCSSM onset (pentad 25-35). The two models proposed herein are expected to facilitate the real-time prediction of the SCSSM onset.

  17. China’s Near Seas Combat Capabilities (China Maritime Study, Number 11)

    Science.gov (United States)

    2014-02-01

    whether alliance partners have differing attitudes toward a war.27 That is, as one former Second Artillery deputy commander has asserted, if attitudes ...differ, Chi- nese deterrence should focus on the dominant country, the one that has the “hard-line attitude .” When attitudes in an alliance are the...137/4/1,298 (April 2011), p. 32. 24. ONI, People’s Liberation Army Navy, p. 46. 25. “Guangzhou HuangPu’s Milk Cow,” China Defense Blog, 15 January

  18. Fishers and Territorial Anxieties in China and Vietnam: Narratives of the South China Sea Beyond the Frame of the Nation

    Directory of Open Access Journals (Sweden)

    Edyta Roszko

    2016-12-01

    Full Text Available In the geopolitical conflict over the South China Sea (SCS, fishers are at the center of Chinese and Vietnamese cartographic imaginations that define the sea as either “Chinese” or “Vietnamese” and hence tied to the disputed territories of the Paracel and Spratly Islands. While their historical presence and customary fishing rights in the SCS have been much publicized in the context of this territorial dispute, the long-standing Cham seafaring trade networks and legacy are ignored by both countries. The ethnic and national categories of Cham, Việt, and Han intersect with occupational categories such as those of fisher, trader, shipbuilder, sailor, and pirate, which in the past represented shifting, relational, and situational activities by the same people. The contemporary use of such professional and national labels produces particular political effects by projecting recent closures and enclosures onto the past, in spite of the common historical, cultural, and ethnic flows that always existed in the SCS. Rather than aiming to legitimize or delegitimize Vietnam’s or China’s territorial claims to the SCS, this article argues that seafaring narratives should be liberated from abstract, anachronistic discourses of sovereignty, territoriality, and territorial anxieties that separate the interconnected histories of the Cham, Vietnamese, and Chinese.

  19. Bioactive Compounds from a Gorgonian Coral Echinomuricea sp. (Plexauridae

    Directory of Open Access Journals (Sweden)

    Jih-Jung Chen

    2012-05-01

    Full Text Available A new labdane-type diterpenoid, echinolabdane A (1, and a new sterol, 6-epi-yonarasterol B (2, were isolated from a gorgonian coral identified as Echinomuricea sp. The structures of metabolites 1 and 2 were elucidated by spectroscopic methods. Echinolabdane A (1 possesses a novel tetracyclic skeleton with an oxepane ring jointed to an α,β-unsaturated-γ-lactone ring by a hemiketal moiety, and this compound is the first labdane-type diterpenoid to be obtained from marine organisms belonging to the phylum Cnidaria. 6-epi-Yonarasterol B (2 is the first steroid derivative to be isolated from gorgonian coral belonging to the genus Echinomuricea, and this compound displayed significant inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils.

  20. Remarkable Impacts of Indian Ocean Sea Surface Temperature on Interdecadal Variability of Summer Rainfall in Southwestern China

    OpenAIRE

    Jingpeng Liu; Hong-Li Ren; Weijing Li; Jinqing Zuo

    2018-01-01

    During the boreal summer from June to August, rainfall in Southwestern China shows substantial interdecadal variabilities on timescales longer than 10 years. Based on observational analyses and numerical modeling, we investigated the characteristics of interdecadal Southwestern China summer rainfall (SWCSR) and its dynamic drivers. We find that the SWCSR is markedly impacted by the interdecadal Indian Ocean basin mode (ID-IOBM) of the sea surface temperature (SST), which may induce anomalous ...

  1. 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

    Science.gov (United States)

    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.

  2. A new species, Gerres septemfasciatus (Perciformes: Gerreidae) from the Chinese coastal waters of the South China Sea

    Science.gov (United States)

    Liu, Jing; Yan, Yunrong

    2009-09-01

    We describe a new species of gerreid fish, Gerres septemfasciatus, based on four specimens collected from the northern South China Sea. G. septemfasciatus most closely resembles G. limbatus in general appearance. However, G. septemfasciatus is distinguished from the latter and other congeners by having 3 to 3.5 scales between the base of the fifth dorsal spine and lateral line. This species has a distinctive color pattern, including 7-8 regular, vertical, blue-grayish bands on its side. The distribution of this species is currently known to include the Chinese coastal waters of the South China Sea, but may be also include the coastal waters of southeastern Asia.

  3. A history of oil and gas exploration in the central and northern parts of the South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J-M

    1985-03-01

    (Marine exploration in the South China Sea dates from 1956. Hydrocarbon exploration can be divided into three periods: local investigation (1956-1965); reconnaissance and discoveries (1970-1979); and thorough investigation and joint exploration with foreign companies (1979present). A series of sedimentary basins - the Beibu Gulf, Southeast Hainan, Zhujiangkou, Yinggehai, and Xisha Trough basins - were delineated on the northern shelf and slope. Wells drilled in the first three basins have indicated commercial oil deposits. There is great hydrocarbon potential on the northern shelf of the South China Sea.)

  4. Errors of Mean Dynamic Topography and Geostrophic Current Estimates in China's Marginal Seas from GOCE and Satellite Altimetry

    DEFF Research Database (Denmark)

    Jin, Shuanggen; Feng, Guiping; Andersen, Ole Baltazar

    2014-01-01

    The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and satellite altimetry can provide very detailed and accurate estimates of the mean dynamic topography (MDT) and geostrophic currents in China's marginal seas, such as, the newest high-resolution GOCE gravity field model GO...... and geostrophic current estimates from satellite gravimetry and altimetry are investigated and evaluated in China's marginal seas. The cumulative error in MDT from GOCE is reduced from 22.75 to 9.89 cm when compared to the Gravity Recovery and Climate Experiment (GRACE) gravity field model ITG-Grace2010 results...

  5. Application of Buoy Observations in Determining Characteristics of Several Typhoons Passing the East China Sea in August 2012

    Directory of Open Access Journals (Sweden)

    Ningli Huang

    2013-01-01

    Full Text Available The buoy observation network in the East China Sea is used to assist the determination of the characteristics of tropical cyclone structure in August 2012. When super typhoon “Haikui” made landfall in northern Zhejiang province, it passed over three buoys, the East China Sea Buoy, the Sea Reef Buoy, and the Channel Buoy, which were located within the radii of the 13.9 m/s winds, 24.5 m/s winds, and 24.5 m/s winds, respectively. These buoy observations verified the accuracy of typhoon intensity determined by China Meteorological Administration (CMA. The East China Sea Buoy had closely observed typhoons “Bolaven” and “Tembin,” which provided real-time guidance for forecasters to better understand the typhoon structure and were also used to quantify the air-sea interface heat exchange during the passage of the storm. The buoy-measured wind and pressure time series were also used to correct the intensity of “Damrey” initially determined by CMA.

  6. Responses of the tropical gorgonian coral Eunicea fusca to ocean acidification conditions

    Science.gov (United States)

    Gómez, C. E.; Paul, V. J.; Ritson-Williams, R.; Muehllehner, N.; Langdon, C.; Sánchez, J. A.

    2015-06-01

    Ocean acidification can have negative repercussions from the organism to ecosystem levels. Octocorals deposit high-magnesium calcite in their skeletons, and according to different models, they could be more susceptible to the depletion of carbonate ions than either calcite or aragonite-depositing organisms. This study investigated the response of the gorgonian coral Eunicea fusca to a range of CO2 concentrations from 285 to 4,568 ppm (pH range 8.1-7.1) over a 4-week period. Gorgonian growth and calcification were measured at each level of CO2 as linear extension rate and percent change in buoyant weight and calcein incorporation in individual sclerites, respectively. There was a significant negative relationship for calcification and CO2 concentration that was well explained by a linear model regression analysis for both buoyant weight and calcein staining. In general, growth and calcification did not stop in any of the concentrations of pCO2; however, some of the octocoral fragments experienced negative calcification at undersaturated levels of calcium carbonate (>4,500 ppm) suggesting possible dissolution effects. These results highlight the susceptibility of the gorgonian coral E. fusca to elevated levels of carbon dioxide but suggest that E. fusca could still survive well in mid-term ocean acidification conditions expected by the end of this century, which provides important information on the effects of ocean acidification on the dynamics of coral reef communities. Gorgonian corals can be expected to diversify and thrive in the Atlantic-Eastern Pacific; as scleractinian corals decline, it is likely to expect a shift in these reef communities from scleractinian coral dominated to octocoral/soft coral dominated under a "business as usual" scenario of CO2 emissions.

  7. Analysis and design of trial well mooring in deepwater of the South China Sea

    Science.gov (United States)

    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.

  8. A peculiar lens-shaped structure observed in the South China Sea.

    Science.gov (United States)

    Lin, Hongyang; Hu, Jianyu; Liu, Zhiyu; Belkin, Igor M; Sun, Zhenyu; Zhu, Jia

    2017-03-28

    Lens-shaped structures within thermocline potentially play a significant role in subsurface transport of mass, heat, and salt in the global ocean. Whilst such structures have been documented in many oceanic regions, none has been observed in the China Seas. This study reports on observations of a lens-shaped structure within thermocline in the southwestern South China Sea in September 2007. This structure had a maximum thickness of approximately 60 m and a horizontal extent exceeding 220 km. This lens was peculiar in that its size is larger than most similar structures documented in the literature. The lens core was characterized by well-mixed water with higher temperature (~28.8 °C), lower salinity (~33.3) and lower potential vorticity (PV) compared to the surrounding waters. Based on an ocean reanalysis, possible generation mechanism of the lens is explored by examining the evolution of surface and subsurface thermohaline properties, and an analysis of vertical PV flux. The lens was likely generated by a mixture of the local mixed-layer water and the water from the coastal jet separation site.

  9. Kinematic parameters of internal waves of the second mode in the South China Sea

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

    2014-06-03

    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.

  11. Performance Calculation of Floating Wind Turbine Tension Leg Platform in the South China Sea

    Directory of Open Access Journals (Sweden)

    Hai Feng Wang

    2015-10-01

    Full Text Available The harvesting of wind energy is expected to increase greatly in the future because of its stability, abundance, and renewability in large coastal states such as China. The floating support structure will likely become the major structural form for wind turbines in the future due to its cost advantages when the water depth reaches 50 m. The 5MW wind turbine model from National Renewable Energy Lab (NREL and the modified tension leg platform model proposed by Harbin Institute of Technology (HIT were applied to certain sea conditions in the South China Sea in order to consider the effects of external load coupling actions. In this study, the internal force, mooring system force, as well as the acceleration, displacement and velocity of the floating structure of the modified HIT Tension Leg Platform (HIT-TLP were calculated. During this process, the physical parameters of its tension leg structure at a specific frequency domain were obtained to find the technical reserves for its practical application in the future.

  12. Response of internal solitary waves to tropical storm Washi in the northwestern South China Sea

    Directory of Open Access Journals (Sweden)

    Z. H. Xu

    2011-11-01

    Full Text Available Based on in-situ time series data from an array of temperature sensors and an acoustic Doppler current profiler on the continental shelf of the northwestern South China Sea, a sequence of internal solitary waves (ISWs were observed during the passage of tropical storm Washi in the summer of 2005, which provided a unique opportunity to investigate the ISW response to the tropical cyclone. The passing tropical storm is found to play an important role in affecting the stratification structure of the water column, and consequently leading to significant variability in the propagating features of the ISWs, such as the polarity reversal and amplitude variations of the waves. The response of the ISWs to Washi can be divided into two stages, direct forcing by the strong wind (during the arrival of Washi and remote forcing via the near-inertial internal waves induced by the tropical storm (after the passage of Washi. The field observations as well as a theoretical analysis suggest that the variations of the ISWs closely coincide with the changing stratification structure and shear currents in accompanied by the typhoon wind and near-inertial waves. This study presents the first observations and analysis of the ISW response to the tropical cyclone in the South China Sea.

  13. Kinematic parameters of internal waves of the second mode in the South China Sea

    Directory of Open Access Journals (Sweden)

    O. Kurkina

    2017-10-01

    Full Text Available 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.

  14. Seasonal fluctuations of ichthyoplankton assemblage in the northeastern South China Sea influenced by the Kuroshio intrusion

    Science.gov (United States)

    Huang, Delian; Zhang, Xia; Jiang, Zhijian; Zhang, Jingping; Arbi, Iman; Jiang, Xin; Huang, Xiaoping; Zhang, Wenjing

    2017-09-01

    The distribution and assemblage of ichthyoplankton related to local hydrographic features, especially intrusion of the Kuroshio Current (KC) and Guangdong Coastal Current (GCC) in the northeastern South China Sea (NESCS) were investigated in this study. A total of 193 species of ichthyoplankton belonging to 141 genera and 66 families were recognized in summer 2015 and late-winter 2016. The ichthyoplankton assemblage was identified with distinct seasonal differences, and the differences were responded well with the oceanography conditions. In summer, the assemblages were identified into offshore and inshore groups, as controlled by the South China Sea Warm Current (SCSWC) in off-shelf, upwelling, and the diluted water from the Pearl River in inshore. In winter, three groups were divided, representing the southwestern inshore, intrusion of the KC in the eastern offshore, and the GCC in the northern inshore area, respectively. Furthermore, Sigmops gracilis and Vinciguerria sp.3 were probably brought into the NESCS by intrusion of the KC from the eastern Luzon Strait. In addition, high ichthyoplankton abundance was found in high chlorophyll a located in upwelling areas in the northern coastal area in summer and in the southwestern Taiwan Bank in winter, respectively. The nutrition outcropped by the upwelling together, and those brought from the Pearl River probably supported high food availability of the ichthyoplankton in the northern coast of the NESCS.

  15. Thinned crustal structure and tectonic boundary of the Nansha Block, southern South China Sea

    Science.gov (United States)

    Dong, Miao; Wu, Shi-Guo; Zhang, Jian

    2016-12-01

    The southern South China Sea margin consists of the thinned crustal Nansha Block and a compressional collision zone. The Nansha Block's deep structure and tectonic evolution contains critical information about the South China Sea's rifting. Multiple geophysical data sets, including regional magnetic, gravity and reflection seismic data, reveal the deep structure and rifting processes. Curie point depth (CPD), estimated from magnetic anomalies using a windowed wavenumber-domain algorithm, enables us to image thermal structures. To derive a 3D Moho topography and crustal thickness model, we apply Oldenburg algorithm to the gravity anomaly, which was extracted from the observed free air gravity anomaly data after removing the gravity effect of density variations of sediments, and temperature and pressure variations of the lithospheric mantle. We found that the Moho depth (20 km) is shallower than the CPD (24 km) in the Northwest Borneo Trough, possibly caused by thinned crust, low heat flow and a low vertical geothermal gradient. The Nansha Block's northern boundary is a narrow continent-ocean transition zone constrained by magnetic anomalies, reflection seismic data, gravity anomalies and an interpretation of Moho depth (about 13 km). The block extends southward beneath a gravity-driven deformed sediment wedge caused by uplift on land after a collision, with a contribution from deep crustal flow. Its southwestern boundary is close to the Lupar Line defined by a significant negative reduction to the pole (RTP) of magnetic anomaly and short-length-scale variation in crustal thickness, increasing from 18 to 26 km.

  16. New record of Japanese snake blenny Xiphasia matsubarai (Perciformes: Blenniidae) from South China Sea

    Science.gov (United States)

    Yi, Murong; Zhao, Chunxu; Su, Xin; Tao, Yajin; Yan, Yunrong

    2017-11-01

    Specimens belonging to the family Blenniidae were collected in a fishery resource investigation from the coastal waters of Xisha Islands and Hainan Island, South China Sea in 2016. Combining morphological results with sequence analysis, we identified one specimen as Xiphasia matsubarai Okada & Suzuki, 1952. This represents a new record in the South China Sea. In morphology, the specimen has the following traits: body elongated, eel-like or ribbon-like in shape; flanks medium flat; the head small bluntly rounded anteriorly and without a moustache; eyes is slightly smaller, on upper lateral position of head, which is about equal to 1/5 of the length of the head; body without scales, lateral line has been degraded; both sides of the upper and lower jaws with a canine; gill is opening at the top of the pectoral fin base, approximately equal to the length of eye diameter. Dorsal fin XI, 96; pectoral fin 10; anal fin II, 95. Head and body grey-brown, including 26 dark grey-brown bands; abdomen and lower operculum yellowish grey and colour lighter; and dorsal base long with dark grey. Origin of dorsal is located over the anterior margin of pupil; black blotch on dorsal fin between 8th and 10th dorsal spine; anal and caudal fins dark grey, pectoral and ventral fins pale yellow. Sequence analysis of cytochrome oxidase subunit I gene (COI) strongly supports the identity of the specimen as X. matsubarai.

  17. Emission characteristics of offshore fishing ships in the Yellow Bo Sea, China.

    Science.gov (United States)

    Liu, Yingshuai; Ge, Yunshan; Tan, Jianwei; Fu, Mingliang; Shah, Asad Naeem; Li, Luqiang; Ji, Zhe; Ding, Yan

    2018-03-01

    Maritime transport has been playing a decisive role in global trade. Its contribution to the air pollution of the sea and coastal areas has been widely recognized. The air pollutant emission inventories of several harbors in China have already been established. However, the emission factors of local ships have not been addressed comprehensively, and thus are lacking from the emission inventories. In this study, on-board emission tests of eight diesel-powered offshore fishing ships were conducted near the coastal region of the northern Yellow Bo Sea fishing ground of Dalian, China. Results show that large amounts of fine particles (<0.5μm, 90%) were found in maneuvering mode, which were about five times higher than those during cruise mode. Emission rates as well as emission factors based on both distance and fuel were determined during the cruise and maneuvering modes (including departure and arrival). Average emission rates and distance-based emission factors of CO, HC and PM were much higher during the maneuvering mode as compared with the cruise mode. However, the average emission rate of Nitrous Oxide (NO x ) was higher during the cruise mode as compared with the maneuvering modes. On the contrary, the average distance-based emission factors of NO x were lower during the cruise mode relative to the maneuvering mode due to the low sailing speed of the latter. Copyright © 2017. Published by Elsevier B.V.

  18. Chemistry, chemoecology, and bioactivity of the South China Sea opisthobranch molluscs and their dietary organisms.

    Science.gov (United States)

    Wang, Jian-Rong; He, Wen-Fei; Guo, Yue-Wei

    2013-01-01

    Opisthobranchs are slow-moving, brightly colored, and shell-less slug. Interestingly, these naked molluscs appear to be free of predation causing great interests to biologists, chemists, and pharmacologists as well. It is well documented that their ability to escape predation is realized by utilizing chemical substances as defensive allomones. Due to their extraordinary capacity to produce a variety of chemical defensive molecules and in particular, some of which exhibited promising pharmacological activities, opisthobranch molluscs became the hotspot of research subject in the recent years. The authors and co-workers have systematically investigated the possible diet relationship between the South China Sea opisthobranch molluscs and their related prey organisms, including sponges, corals, and algae in the last decade. A series of interesting results have been obtained concerning the chemistry and chemoecology of the studied marine organisms. The present review focuses on recent development dealing with chemistry, chemoecology, and bioactivity of the South China Sea opisthobranch molluscs and their dietary organisms. Some selected representative examples are described in detail.

  19. Actinomycetes from the South China Sea sponges: isolation, diversity, and potential for aromatic polyketides discovery

    Science.gov (United States)

    Sun, Wei; Zhang, Fengli; He, Liming; Karthik, Loganathan; Li, Zhiyong

    2015-01-01

    Marine sponges often harbor dense and diverse microbial communities including actinobacteria. To date no comprehensive investigation has been performed on the culturable diversity of the actinomycetes associated with South China Sea sponges. Structurally novel aromatic polyketides were recently discovered from marine sponge-derived Streptomyces and Saccharopolyspora strains, suggesting that sponge-associated actinomycetes can serve as a new source of aromatic polyketides. In this study, a total of 77 actinomycete strains were isolated from 15 South China Sea sponge species. Phylogenetic characterization of the isolates based on 16S rRNA gene sequencing supported their assignment to 12 families and 20 genera, among which three rare genera (Marihabitans, Polymorphospora, and Streptomonospora) were isolated from marine sponges for the first time. Subsequently, β-ketoacyl synthase (KSα) gene was used as marker for evaluating the potential of the actinomycete strains to produce aromatic polyketides. As a result, KSα gene was detected in 35 isolates related to seven genera (Kocuria, Micromonospora, Nocardia, Nocardiopsis, Saccharopolyspora, Salinispora, and Streptomyces). Finally, 10 strains were selected for small-scale fermentation, and one angucycline compound was detected from the culture extract of Streptomyces anulatus strain S71. This study advanced our knowledge of the sponge-associated actinomycetes regarding their diversity and potential in producing aromatic polyketides. PMID:26483773

  20. Mean relative sea level rise along the coasts of the China Seas from mid-20th to 21st centuries

    Science.gov (United States)

    Chen, Nan; Han, Guoqi; Yang, Jingsong

    2018-01-01

    Mean relative sea level (MRSL) rise has caused more frequent flooding in many parts of the world. The MRSL rise varies substantially from place to place. Here we use tide-gauge data and satellite measurements to examine past MRSL trends for the coasts of the China Seas. We then combine climate model output and satellite observations to provide MRSL projections in the 21st century. The MRSL trend based on tide-gauge data shows substantial regional variations, from 1 to 5 mm/yr. The vertical land motion (VLM) based on altimetry and tide-gauge (ATG) data indicates large land subsidence at some tide-gauge locations, consistent with the Global Positioning Systems (GPS)-based VLM but different significantly from small uplift estimated by a Glacial Isostatic Adjustment (GIA) model, which suggests other important factors causing the VLM instead of the GIA process. When GPS- or ATG-based VLM estimates are used, the projected MRSL rise between 1986-2005 and 2081-2100 at tide-gauge sites varies from 60 to 130 cm under the Representative Concentration Pathway 8.5 (RCP8.5) scenario of the Intergovernmental Panel on Climate Change (IPCC). Our projections are significantly larger than those of IPCC and other literature, as a result of accounting for the land subsidence derived from observations. Steric and dynamic ocean effects and land-ice melt effects are comparable (about 30 cm each) and do not vary much over the tide-gauge locations. The VLM effect varies from -10 to 60 cm. The projections between 1986-2005 and 2081-2100 under RCP4.5 show a similar spatial distribution to that under RCP8.5, with a smaller amount of rise by 18 cm on average for this region.

  1. High spatial variability of coral, sponges and gorgonian assemblages in a well preserved reef

    Directory of Open Access Journals (Sweden)

    Patricia González-Díaz

    2010-06-01

    Full Text Available The main goal of this research was to obtain baseline field data of the composition of sponges, corals, and gorgonian assemblages that can be used as a reference for future analyses of anthropogenic impact. We tested the hypothesis that relatively homogeneous and well preserved reef units can present notable natural variability in the composition of their communities which are unassociated with changes in land proximity or a human impact gradient. Research was carried out in July 2006 at Los Colorados reef, located in the northwestern region of Pinar del Río Province, Cuba at 12 sampling stations. The biotopes selected were crest, terrace edge and spur and grove. Ecological indicators were diversity of corals, species composition, density of corals, hydrocorals, gorgonians and sponges, and density of selected coral species. A total of 2659 colonies of scleractineans corals representing 36 species were counted. The most abundant species in the crest biotope were Millepora alcicornis, Acropora palmata and Porites astreoides; in the terrace edge and spur and grove, the most abundant species were Siderastrea siderea, Stephanocoenia intersepta, Porites astreoides, Agaricia agaricites and Montastraea cavernosa. We found differences among sites for several indicators (e.g. density of corals, sponges and gorgonians and for selected species, but they could not be associated to any gradient of land influence or human impact. Therefore, sites inside a relatively homogeneous reef unit can present notable natural differences in the composition of their communities. Rev. Biol. Trop. 58 (2: 621-634. Epub 2010 June 02.

  2. High spatial variability of coral, sponges and gorgonian assemblages in a well preserved reef.

    Science.gov (United States)

    González-Díaz, Patricia; González-Sansón, Gaspar; Alvarez Fernández, Sergio; Perera Pérez, Orlando

    2010-06-01

    The main goal of this research was to obtain baseline field data of the composition of sponges, corals, and gorgonian assemblages that can be used as a reference for future analyses of anthropogenic impact. We tested the hypothesis that relatively homogeneous and well preserved reef units can present notable natural variability in the composition of their communities which are unassociated with changes in land proximity or a human impact gradient. Research was carried out in July 2006 at Los Colorados reef, located in the northwestern region of Pinar del Río Province, Cuba at 12 sampling stations. The biotopes selected were crest, terrace edge and spur and grove. Ecological indicators were diversity of corals, species composition, density of corals, hydrocorals, gorgonians and sponges, and density of selected coral species. A total of 2659 colonies of scleractineans corals representing 36 species were counted. The most abundant species in the crest biotope were Millepora alcicornis, Acropora palmata and Porites astreoides; in the terrace edge and spur and grove, the most abundant species were Siderastrea siderea, Stephanocoenia intersepta, Porites astreoides, Agaricia agaricites and Montastraea cavernosa. We found differences among sites for several indicators (e.g. density of corals, sponges and gorgonians and for selected species), but they could not be associated to any gradient of land influence or human impact. Therefore, sites inside a relatively homogeneous reef unit can present notable natural differences in the composition of their communities.

  3. A "great wall of sand" in the South China Sea? Political, legal and military aspects of the island dispute

    OpenAIRE

    Paul, Michael

    2016-01-01

    China has set new records in the ways, means and speed with which it has expanded its outposts in the South China Sea. Neighbouring states such as Vietnam have also extended their bases on small islands and reefs, but they have done so over many years and not within a few months. The total surface area created by China has been ironically dubbed "The Great Wall of Sand" by the commander of the US Pacific Fleet. Despite Beijing’s claims to the contrary, the expansions signal an emerging milita...

  4. Levels of persistent organic pollutants in air in China and over the Yellow Sea

    Science.gov (United States)

    Lammel, Gerhard; Ghim, Young-Sung; Grados, Amélie; Gao, Huiwang; Hühnerfuss, Heinrich; Lohmann, Rainer

    The occurrence of persistent toxic substances (PTS) in China and possibly their regional transport in the Yellow and East China Seas region was studied. Organochlorines in atmospheric gas-phase and particulate matter were collected by high-volume sampling (filters and polyurethane foams) during 2 weeks in June 2003 (dry season) simultaneously at a Yellow Sea coastal site in an urban area, Qingdao, China, and a rural island site, Gosan, Jeju Island, Korea. Using GC methods, the samples were analysed for 9 persistent organic pollutants (POPs) regulated under the global POP convention, namely aldrin, chlordane ( cis- and trans-isomers CC and TC), DDT and metabolites ( o, p'-DDT, p, p'-DDD, and p, p'-DDE), dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and PCB (congeners number 28, 52, 101, 153 and 180), and for hexachlorocyclohexane ( α-, β- and γ-isomers), a PTS and now considered for regulation under the convention, too. At the coastal site additionally o, p'-DDE and -DDD, β-endosulfan, isodrin, heptachlorepoxide and δ-HCH, and at the island site additionally p, p'-DDT and 12 additional PCB congeners were analysed. 9 samples were collected at the coastal and 15 (for PCBs 5) at the island site. Long-range advection pathways were determined based on analysed back-trajectory calculations. The mean concentrations of DDT and its metabolites, HCB, HCH, and PCB at the coast were in the 100-1000 pg m -3 range. Higher concentrations prevailed during nighttime. The levels were in general lower at the island site, but not for DDT. Local sources are likely. PCBs were even 2 orders of magnitude lower, suggesting that PCBs are not subject to regional transport but elevated concentrations in air are limited to the source areas. Organochlorine pesticide levels on the other hand were seemingly determined by regional transport over Mainland China rather than by emissions in the coastal area. The currently used pesticides mirex and chlordane were found at elevated

  5. Remote impact of North Atlantic sea surface temperature on rainfall in southwestern China during boreal spring

    Science.gov (United States)

    Li, Gang; Chen, Jiepeng; Wang, Xin; Luo, Xia; Yang, Daoyong; Zhou, Wen; Tan, Yanke; Yan, Hongming

    2018-01-01

    As an important oceanic signal, the North Atlantic sea surface temperature (SST) affects not only the climate variability over East China and Northeast China but also can affect climate variability over southwestern China (SWC). Based on station rainfall data and reanalysis datasets, the present study investigates the relationship of North Atlantic SST with SWC rainfall during boreal spring for the period 1979-2016. The results show that there is a significant positive correlation between North Atlantic SST and SWC rainfall during boreal spring. The atmospheric circulation over southern Asia associated with North Atlantic SST is favorable for positive rainfall anomalies. Further analyses show that North Atlantic SST can induce a North Atlantic-western Russia-western Tibetan Plateau-SWC (NRTC) teleconnection wave train from upper level to low level. At low level, two anomalous anticyclones are found over the mid-high latitude of North Atlantic and the western Tibetan Plateau, and two anomalous cyclones are observed over the western Russia and Bay of Bengal (BOB), respectively. The NRTC teleconnection wave train plays a bridging role between the North Atlantic SST and SWC rainfall during boreal spring. Both the observational analysis and two numerical experiments suggest that the North Atlantic SST during boreal spring can induce an anomalous cyclone over BOB by the NRTC teleconnection pattern. The anomalous cyclone over BOB favors moisture transport to SWC, accompanying with significant anomalous ascending motion, and thus results in positive rainfall anomalies in SWC during boreal spring.

  6. Characterization of aerosol over the Northern South China Sea during two cruises in 2003

    Science.gov (United States)

    Zhang, Xingying; Zhuang, Guoshun; Guo, Jinghua; Yin, Kedong; Zhang, Peng

    Atmospheric transport of trace elements has been found to be an important pathway for their input to the ocean. TSP, PM10, and PM2.5 aerosol samples were collected over the Northern South China Sea in two cruises in 2003 to estimate the input of aerosol from continent to the ocean. About 23 elements and 14 soluble ions in aerosol samples were measured. The average mass concentration of TSP in Cruise I in January (78 μg m -3) was ˜twice of that in Cruise II in April (37 μg m -3). Together with the crustal component, heavy metals from pollution sources over the land (especially from the industry and automobiles in Guangzhou) were transported to and deposited into the ocean. The atmospheric MSA concentrations in PM2.5 (0.048 μg m -3 in Cruise I and 0.043 μg m -3 in Cruise II) over Northern South China Sea were comparable to those over other coastal regions. The ratio of non-sea-salt (NSS)-sulfate to MSA is 103-655 for Cruise I and 15-440 for Cruise II in PM2.5 samples, which were much higher than those over remote oceans. The estimated anthropogenic sulfate accounts for 83-98% in Cruise I and 63-95% in Cruise II of the total NSS-sulfate. Fe (II) concentration in the aerosols collected over the ocean ranged from 0.1 to 0.9 μg m -3, accounting for 16-82% of the total iron in the aerosol, which could affect the marine biogeochemical cycle greatly.

  7. Dongsha Atoll: A potential thermal refuge for reef-building corals in the South China Sea.

    Science.gov (United States)

    Tkachenko, Konstantin S; Soong, Keryea

    2017-06-01

    Dongsha Atoll (also known as the Pratas Islands), the northernmost atoll in the South China Sea, experiences two contrasting physical phenomena: repetitive anomalies of the sea surface temperature exceeding the coral bleaching threshold and regular effects of the world's strongest internal waves resulting in the rhythmic upwelling of cold deep waters at the outer reef slopes of the atoll. This unique combination may result in significant differences in coral species composition and structure between the lagoon and forereef. Surveys conducted in August-September 2016 at 12 study sites in the 2-15 m depth range at Dongsha Atoll revealed a clear spatial separation between 'thermally-susceptible' stony coral genera, including Acropora, Pocillopora and Montipora, which mainly inhabited the forereef, and 'thermally-resistant' genera, including massive Porites, foliaceous Echinopora, Pavona and Turbinaria, which mainly resided in the lagoon. The mean coral cover and species richness on the forereef were respectively 1.8 and 1.4 times higher than those in the lagoon (61.3% and 98 species on the forereef vs. 34.2% and 69 species in the lagoon). Coral mortality rates, expressed as the ratio of dead to live stony corals, showed the same pattern (0.4 in the lagoon vs. 0.009 on the forereef). Furthermore, in a laboratory experiment, 'thermally-susceptible' taxa from the lagoon, (e.g. Pocillopora verrucosa and P. damicornis), exhibited higher resistance to bleaching than did their counterparts from the forereef. The present findings indicate that Dongsha Atoll is a potential thermal refuge for reef-building corals in the northern South China Sea and reveal the development of resilience and resistance to bleaching in coral communities of the lagoon. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Tides and Their Dynamics over the Sunda Shelf of the Southern South China Sea.

    Science.gov (United States)

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

    2016-01-01

    A three-dimensional Regional Ocean Modelling System is used to study the tidal characteristics and their dynamics in the Sunda Shelf of the southern South China Sea. In this model, the outer domain is set with a 25 km resolution and the inner one, with a 9 km resolution. Calculations are performed on the inner domain. The model is forced at the sea surface by climatological monthly mean wind stress, freshwater (evaporation minus precipitation), and heat fluxes. Momentum and tracers (such as temperature and salinity) are prescribed in addition to the tidal heights and currents extracted from the Oregon State University TOPEX/Poseidon Global Inverse Solution (TPXO7.2) at the open boundaries. The results are validated against observed tidal amplitudes and phases at 19 locations. Results show that the mean average power energy spectrum (in unit m2/s/cph) for diurnal tides at the southern end of the East Coast of Peninsular Malaysia is approximately 43% greater than that in the East Malaysia region located in northern Borneo. In contrast, for the region of northern Borneo the semidiurnal power energy spectrum is approximately 25% greater than that in the East Coast of Peninsular Malaysia. This implies that diurnal tides are dominant along the East Coast of Peninsular Malaysia while both diurnal and semidiurnal tides dominate almost equally in coastal East Malaysia. Furthermore, the diurnal tidal energy flux is found to be 60% greater than that of the semidiurnal tides in the southern South China Sea. Based on these model analyses, the significant tidal mixing frontal areas are located primarily off Sarawak coast as indicated by high chlorophyll-a concentrations in the area.

  9. Five Sarsiellidae ostracods (Crustacea: Myodocopida) from the South Coast of Korea (East China Sea).

    Science.gov (United States)

    Karanovic, Ivana; Soh, Ho-Young

    2015-04-17

    The East China Sea is part of the Warm Temperate Northwest Pacific zoogeographic province and, as such, has a high biodiversity and many tropical and subtropical biotic elements. Nevertheless, many invertebrate groups from this area remain poorly studied. Ostracods are one of them, especially those belonging to the subclass Myodocopa. In this paper we provide the first data on a diverse myodocopid family, Sarsiellidae, not only for the East China Sea, but also for Korea. Five species are reported in this paper from three Korean islands (Jeju, Chuja, and Maemul), and they are only a part of the ostracods collected during this study, indicating a high diversity of the group in this region. Three new species, Eurypylus koreanus sp. nov., Eusarsiella hanguk sp. nov., and Sarsiella nereis sp. nov., clearly stand apart from their respective congeners, mostly by prominent shell characters but also by details of the soft part morphology. Their affinity though clearly indicates a close connection of the region with the more southern zoogeographical realms, especially Central Indo Pacific and partly Temperate Australasia. Two species previously known from Japan (north part of the Sea of Japan and southeastern part of the Pacific Coast of Japan), Sarsiella japonica Hiruta, 1977 and S. misakiensis Kajiyama, 1912, are redescribed. Based on 11 newly obtained COI sequences we construct a preliminary phylogenetic tree, which supports previous hypotheses based on the morphological data, that Eusarsiella Cohen & Kornicker, 1975 is a polyphyletic taxon. With the maps of species distribution provided for each of the three genera, we give an overview of their current zoogeography, and clearly indicate areas that have no data, mostly due to the lack of investigation.

  10. Brief Introduction on the Korea-China Collaborative Research on the Wide-angle Seismic Experiment of the Yellow Sea

    Science.gov (United States)

    Kim, J.; Kim, K. H.; Kim, H. J.; Hao, T.; Zhang, X.

    2016-12-01

    Small to moderate earthquakes occurred in the Yellow Sea, such as Seogyuckryulbi-do earthquake (ML 5.1, April 1, 2014) and Heuksan-do earthquake (ML 4.9, April 21, 2013). Although the earthquakes occurred in a region of apparent low seismicity, they attracted much attention for the seismic hazards and rose questions about the reevaluation the seismicity of the Yellow Sea. Although several tectonic models have been proposed from the observations in China and Korea, it is still not clear which one can answer the tectonic problem. Furthermore, the seismicity of the Yellow Sea has been rarely investigated since the region is located outside seismic networks. It is suspected that the seismicity of the region is related to basin boundary faults created by rifting and tectonic inverting. In order to evaluate earthquake hazard of the Yellow Sea, it is required to identify spatial distribution of the faults. In this study, a deep seismic profile was carried out using ocean bottom seismometers (OBS's) to investigate the crust and upper mantle structure beneath the Yellow Sea and their relationship with shallower structures. The deep seismic profile was conducted by M/V Discoverer and R/V Eardo from June 21 to July 3, 2016. The air-gun array of 6,640 cu. in. shot along the 405 km profile across the Yellow Sea, which was recorded by 31 OBS's at a 13.5 km spacing. Besides, 10 temporary land stations were also installed onshore along the profile. This Korea-China collaborative wide-angle seismic experiment was first time across the Yellow Sea. Through this study, it is expected that Korea and China would build a credible cooperation on the study of the Yellow Sea region in future, and it's helpful to verify previously proposed tectonic evolution models for northeastern Asia including the Yellow Sea.

  11. Yellowfin Tuna (Thunnusalbacares Fishing Ground Forecasting Model Based On Bayes Classifier In The South China Sea

    Directory of Open Access Journals (Sweden)

    Zhou Wei-feng

    2017-08-01

    Full Text Available Using the yellowfin tuna (Thunnusalbacares,YFTlongline fishing catch data in the open South China Sea (SCS provided by WCPFC, the optimum interpolation sea surface temperature (OISST from CPC/NOAA and multi-satellites altimetric monthly averaged product sea surface height (SSH released by CNES, eight alternative options based on Bayes classifier were made in this paper according to different strategies on the choice of environment factors and the levels of fishing zones to classify the YFT fishing ground in the open SCS. The classification results were compared with the actual ones for validation and analyzed to know how different plans impact on classification results and precision. The results of validation showed that the precision of the eight options were 71.4%, 75%, 70.8%, 74.4%, 66.7%, 68.5%, 57.7% and 63.7% in sequence, the first to sixth among them above 65% would meet the practical application needs basically. The alternatives which use SST and SSH simultaneously as the environmental factors have higher precision than which only use single SST environmental factor, and the consideration of adding SSH can improve the model precision to a certain extent. The options which use CPUE’s mean ± standard deviation as threshold have higher precision than which use CPUE’s 33.3%-quantile and 66.7%-quantile as the threshold

  12. Arctic and Antarctic Oscillation signatures in tropical coral proxies over the South China Sea

    Directory of Open Access Journals (Sweden)

    D.-Y. Gong

    2009-05-01

    Full Text Available Arctic Oscillation (AO and Antarctic Oscillation (AAO are the leading modes of atmospheric circulation in mid-high latitudes. Previous studies have revealed that the climatic influences of the two modes are dominant in extra-tropical regions. This study finds that AO and AAO signals are also well recorded in coral proxies in the tropical South China Sea. There are significant interannual signals of AO and AAO in the strontium (Sr content, which represents the sea surface temperature (SST. Among all the seasons, the most significant correlation occurs during winter in both hemispheres: the strongest AO-Sr and AAO-Sr coral correlations occur in January and August, respectively. This study also determined that the Sr content lags behind AO and AAO by 1–3 months. Large-scale anomalies in sea level pressure and horizontal wind at 850 hPa level support the strength of AO/AAO-coral teleconnections. In addition, a comparison with oxygen isotope records from two coral sites in neighboring oceans yields significant AO and AAO signatures with similar time lags. These results help to better understand monsoon climates and their teleconnection to high-latitude climate changes.

  13. Past 140-year environmental record in the northern South China Sea: Evidence from coral skeletal trace metal variations

    International Nuclear Information System (INIS)

    Song, Yinxian; Yu, Kefu; Zhao, Jianxin; Feng, Yuexing; Shi, Qi; Zhang, Huiling; Ayoko, Godwin A.; Frost, Ray L.

    2014-01-01

    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. -- Highlights: • Geochemical behaviors of trace elements in corals from South China Sea were investigated. • Terrestrial input, SST, war and infrastructure explain about 77.4% of elements behaviors in coral. • Changes of trace elements in coral of Xisha Islands were mainly impacted by local activities. • Spatial change of elements in seawater by was evaluated in 1986–1997 using distribution coefficient K D of coral. -- 140-year changes in the trace metals in corals from South China Sea were investigated. The spatiotemporal change model of the metals in seawater was reconstructed using coral record

  14. Diagnosing the leading mode of interdecadal covariability between the Indian Ocean sea surface temperature and summer precipitation in southern China

    Science.gov (United States)

    Liu, Jingpeng; Ren, Hong-Li; Li, Weijing; Zuo, Jinqing

    2018-03-01

    Precipitation in southern China during boreal summer (June to August) shows a substantial interdecadal variability on the timescale longer than 8 years. In this study, based on the analysis of singular value decomposition, we diagnose the leading mode of interdecadal covariability between the observational precipitation in southern China and the sea surface temperature (SST) in the Indian Ocean. Results indicate that there exist a remarkable southern China zonal dipole (SCZD) pattern of interdecadal variability of summer precipitation and an interdecadal Indian Ocean basin mode (ID-IOBM) of SST. It is found that the SCZD is evidently covaried with the ID-IOBM, which may induce anomalous inter-hemispheric vertical circulation and atmospheric Kelvin waves. During the warm phase of the ID-IOBM, an enhanced lower-level convergence and upper-level divergence exist over the tropical Indian Ocean, which is a typical Gill-Matsuno-type response to the SST warming. Meanwhile, the accompanied upper-level outflow anomalies further converge over the Indo-China peninsula, resulting in a lower-level anticyclone that contributes to reduction of the eastward moisture transport from the Bay of Bengal to the west part of southern China. In addition, the Kelvin wave-like pattern, as a response of the warm ID-IOBM phase, further induces the lower-level anticyclonic anomaly over the South China Sea-Philippines. Such an anticyclonic circulation is favorable for more water vapor transport from the East China Sea into the east part of southern China. Therefore, the joint effects of the anomalous inter-hemispheric vertical circulation and the Kelvin wave-like pattern associated with the ID-IOBM may eventually play a key role in generating the SCZD pattern.

  15. The origin of gas seeps and shallow gas in northern part of South China Sea

    Science.gov (United States)

    Li, M.; Jin, X.

    2003-04-01

    The northern part of South China Sea is of passive continental margin, which geologic units include shelf, slope and deep sea basin. There are rifting basins forming during Paleogene (or Cretaceous ?) to Quaternary developed on shelf and slope, which sediments are dominated by fluvial and lake clastic rock of Paleogene, and marine clastic rock and carbonate of Neogene - Quaternary. The main basins include the Pearl River Mouth Basin, Beibu Gulf basin, Qiongdongnan Basin and Yinggehai basin. They contain rich oil and gas resources, and have become important industrial oil and gas producing region in South China Sea. With the increasing of petroleum exploration actives and marine petroleum engineering, it has been paid more attention to the investigation and research of gas seeps and shallow gas, for they become a potential threaten to the marine engineering while they are regarded as the indicators of industrial oil and gas. By study the distribution and geochemical characteristics of gas seeps in northeast part of Yinggehai basin and shallow gas in sediments on slope, combined with their regional geologic background, this paper deals with the origin, migration pathway and emission mechanism of gas seeps and shallow gas in northern part of South China Sea, for providing a base knowledge for the evaluation of marine engineering geology. In northeast part of Yinggehai basin gas seeps have been found and recorded for near 100 years. During 1990s, as a part of petroleum exploration, the gas seeps in the basin have been investigated and research by oil companies (Baojia Huang et al., 1992; Jiaqiong He et al., 2000). Gas seeps were found in shallow water area along southwest coast of Hainan Island, water depth usually less than 50 m. The occurrence of gas seeps can be divided into two types: (1) gas continuously emission, continuous gas bubbles groups can be detected by sonar underwater and observed on water surface. (2) gas intermittently emission, the time intervals

  16. The world's largest macroalgal bloom in the Yellow Sea, China: Formation and implications

    Science.gov (United States)

    Liu, Dongyan; Keesing, John K.; He, Peimin; Wang, Zongling; Shi, Yajun; Wang, Yujue

    2013-09-01

    The world's largest trans-regional macroalgal blooms during 2008-2012 occurred in the Yellow Sea, China. This review addresses the causes, development and future challenges in this unique case. Satellite imagery and field observations showed that the macroalgal blooms in the Yellow Sea originated from the coast of Jiangsu province and that favorable geographic and oceanographic conditions brought the green macroalgae from the coast offshore. Optimal temperature, light, nutrients and wind contributed to the formation and transport of the massive bloom north into the Yellow Sea and its deposition onshore along the coast of Shandong province. Morphological and genetic evidence demonstrated that the species involved was Ulva prolifera, a fouling green commonly found growing on structures provided by facilities of Porphyra aquaculture. Large scale Porphyra aquaculture (covering >20,000 ha) along the Jiangsu coast thus hypothetically provided a nursery bed for the original biomass of U. prolifera. Porphyra growers remove U. prolifera from the mariculture rafts, and the cleaning releases about 5000 wet weight tonnes of green algae into the water column along the coast of Jiangsu province; the biomass then is dispersed by hydrographic forcing, and takes advantage of rather high nutrient supply and suitable temperatures to grow to impressive levels. Certain biological traits of U. prolifera —efficient photosynthesis, rapid growth rates, high capacity for nutrient uptake, and diverse reproductive systems— allowed growth of the original 5000 tonnes of U. prolifera biomass into more than one million tonnes of biomass in just two months. The proliferation of U. prolifera in the Yellow Sea resulted from a complex contingency of circumstances, including human activity (eutrophication by release of nutrients from wastewater, agriculture, and aquaculture), natural geographic and hydrodynamic conditions (current, wind) and the key organism's biological attributes. Better

  17. Ozone pollution around a coastal region of South China Sea: interaction between marine and continental air

    Science.gov (United States)

    Wang, Hao; Lyu, Xiaopu; Guo, Hai; Wang, Yu; Zou, Shichun; Ling, Zhenhao; Wang, Xinming; Jiang, Fei; Zeren, Yangzong; Pan, Wenzhuo; Huang, Xiaobo; Shen, Jin

    2018-03-01

    Marine atmosphere is usually considered to be a clean environment, but this study indicates that the near-coast waters of the South China Sea (SCS) suffer from even worse air quality than coastal cities. The analyses were based on concurrent field measurements of target air pollutants and meteorological parameters conducted at a suburban site (Tung Chung, TC) and a nearby marine site (Wan Shan, WS) from August to November 2013. The observations showed that the levels of primary air pollutants were significantly lower at WS than those at TC, while the ozone (O3) value was greater at WS. Higher O3 levels at WS were attributed to the weaker NO titration and higher O3 production rate because of stronger oxidative capacity of the atmosphere. However, O3 episodes were concurrently observed at both sites under certain meteorological conditions, such as tropical cyclones, continental anticyclones and sea-land breezes (SLBs). Driven by these synoptic systems and mesoscale recirculations, the interaction between continental and marine air masses profoundly changed the atmospheric composition and subsequently influenced the formation and redistribution of O3 in the coastal areas. When continental air intruded into marine atmosphere, the O3 pollution was magnified over the SCS, and the elevated O3 ( > 100 ppbv) could overspread the sea boundary layer ˜ 8 times the area of Hong Kong. In some cases, the exaggerated O3 pollution over the SCS was recirculated to the coastal inshore by sea breeze, leading to aggravated O3 pollution in coastal cities. The findings are applicable to similar mesoscale environments around the world where the maritime atmosphere is potentially influenced by severe continental air pollution.

  18. Long-term changes of South China Sea surface temperatures in winter and summer

    Science.gov (United States)

    Park, Young-Gyu; Choi, Ara

    2017-07-01

    Utilizing available atmospheric and oceanographic reanalysis data sets, the long-term trend in South China Sea (SCS) sea surface temperature (SST) between 1950 and 2008 and the governing processes are investigated. Both winter and summer SST increased by comparable amounts, but the warming patterns and the governing processes were different. Strong warming in winter occurred in a deep central area, and during summer in the southern region. In winter the net heat flux into the sea increased, contributing to the warming. The spatial pattern of the heat flux, however, was different from that of the warming. Heat flux increased over the coastal area where warming was weaker, but decreased over the deeper area where warming was stronger. The northeasterly monsoon wind weakened lowering the shoreward Ekman transport and the sea surface height gradient. The cyclonic gyre which transports cold northern water to the south weakened, thereby warming the ocean. The effect was manifested more strongly along the southward western boundary current inducing warming in the deep central part. In summer however, the net surface heat flux decreased and could not contribute to the warming. Over the southern part of the SCS, the weakening of the southwesterly summer monsoon reduced southeastward Ekman transport, which is parallel to the mean SST gradient. Southeastward cold advection due to Ekman transport was reduced, thereby warming the surface near the southeastern boundary of the SCS. Upwelling southeast of Vietnam was also weakened, raising the SST east of Vietnam contributing to the southern summer warming secondarily. The weakening of the winds in each season was the ultimate cause of the warming, but the responses of the ocean that lead to the warming were different in winter and summer.

  19. Late Quaternary climatic forcing on the terrigenous supply in the northern South China Sea: Input from magnetic studies

    Science.gov (United States)

    Chen, Quan; Kissel, Catherine; Liu, Zhifei

    2017-08-01

    The detrital component of marine sediment is a powerful recorder of paleoenvironmental changes in a marginal sea such as the South China Sea. This is in particular valid for the magnetic fraction that is one of the key parameters for paleoenvironmental studies in the South China Sea, although poorly used so far. We report here on the analysis of the magnetic properties of a 50 m-long sedimentary sequence retrieved from the northern South China Sea, on the continental slope off the Pearl River mouth. Magnetic minerals with different coercivities (magnetite, pyrrhotite, and hematite) are mixed. The variations in relative content of these magnetic minerals illustrate influences of various external forcing mechanisms at different timescales. The pyrrhotite content exhibits a long-term increase, which is also observed in illite + chlorite content, indicating a continuous enhancement of supply from Taiwan most likely related to active Taiwan orogeny. Glacial-interglacial fluctuations are characterized by more magnetite and pyrrhotite with coarser silt and magnetic grains during glacials than interglacials. This is attributed to sea-level changes with the enormous continental shelf exposed during glacials, in turn affecting the sediment transport distance and pathway. On a shorter timescale, larger hematite inputs in fine-grained sediments coincide with precession minima. We suggest that this periodic hematite supply change is related to the eolian dust deposited at the studied site in addition to the fluvial and oceanic transported materials.

  20. The Legal Basis of the People’s Republic of China’s East China Sea Air Defense Identification Zone

    Directory of Open Access Journals (Sweden)

    Ching Chang

    2016-04-01

    Full Text Available As the People’s Republic of China defined its East China Sea Air Defense Identification Zone (ADIZ on November 23, 2013, there were three legal decrees, the Law of the People’s Republic of China on National Defense established on March 14, 1997, the Law of the People’s Republic of China on Civil Aviation established on October 30, 1995, and the Basic Rules on Flight of the People’s Republic of China established on July 27, 2001, which have been quoted as the legal basis to define the airspace within the area enclosed by China’s outer limit of the territorial sea and another six geographical points specified by the statement as the PRC East China Sea ADIZ. Following the government statement, another announcement of the aircraft identification rules for the East China Sea Air Defense Identification Zone of the People’s Republic of China was immediately issued by the PRC Ministry of National Defense. The purpose of this paper is to explore various key legal issues to ascertain the legal basis of this East China Sea ADIZ. Besides, the paper will further compare the air defense identification zone with airspaces such as aerodrome flight airspace, airway, air route, prohibited area, restricted area and danger area as well as air corridor, fuel dumping area and temporary flight airspace defined by the previously mentioned PRC legal decrees in order to identify their differences and similarities. It may also be assessed by the factual consequences after establishing the air defense identification zone to decide whether treating the measures of defining air defense identification as the attempt of claiming sovereignty, expanding sovereign territory or sphere of influence, enlarging air defense region, increasing the coverage of air military activities or even using it to present national strength and establishing pride or to test the responses of other states around the disputed territories is eventually reasonable judgments or overstated

  1. 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

    Science.gov (United States)

    2016-02-16

    Philippines’ South China Sea concerns and why it is now attempting to actively deter China. This paper will provide justification for why the US and the...ultimate strategic objectives in the region. The idea of the “China Dream ” has been advocated which means that China’s grand strategy is to become...build a lasting partnership with China. Another credible argument against reestablishing permanent US bases in the Philippines is why build up

  2. Sedimentary and Paleoceanographic Responses to the South China Sea Basin Evolution

    Science.gov (United States)

    Jian, Z.; Liu, Z.; Jin, H.; Larsen, H. C.; Alvarez Zarikian, C. A.; Stock, J. M.; Sun, Z.; Klaus, A.

    2017-12-01

    As the largest marginal sea of the western Pacific, the South China Sea (SCS) has experienced a complete Wilson cycle, which had inevitably exerted a profound impact on the sedimentary environment and ocean circulation. Based on the results of four ODP/IODP expeditions to the SCS since 1999, together with other research data in this region, this study aims to explore the sedimentary and paleoceanographic responses to the tectonic events and basin evolution in the SCS. The early history of the SCS from land to deep sea was revealed by foraminiferal fauna: (1) The SCS evolved from continental shelf to an upper bathyal environment around the Oligocene/Eocene boundary, and significantly deepened at the turn of Oligocene/Miocene; (2) The early Oligocene SCS was deep but its shelf was narrow, evidenced by the Para-Tethys type deep-sea agglutinated benthic foraminifers and abundant transported shallow-water species at ODP Site 1148. Along with the SCS basin formation and the development of this semi-closed basin, the deep-sea benthic foraminiferal δ13C decreased when the Antarctic ice sheet began to reestablish at 14 Ma, the Indonesian Seaway and the southern SCS deep-water channel were closed at 10 Ma, the Luzon arc collided with Taiwan at 6.5 Ma, and the Bashi Strait was restricted at 1.2 Ma. Nd isotopes of shark teeth at ODP Site 1148 also support these inferences. An early to middle Miocene succession of red clay was found at all sites deeper than 3500 m water depth, which may be correlated to a basin-wide event related to deep circulation of oxygenated water from the western Pacific. After the earliest late Miocene carbonate crash, the red clay disappeared while the large carbonate platforms were drowned and remarkably shrank in the SCS. Late Miocene sediments display a succession of hemi-pelagic and turbidite deposits, indicating that the deep basin entered its modern state below the CCD. Frequent turbidites ended when Pliocene growth of deep-sea manganese

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

    Science.gov (United States)

    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.

  4. Modeled connectivity of Acropora millepora populations from reefs of the Spratly Islands and the greater South China Sea

    Science.gov (United States)

    Dorman, Jeffrey G.; Castruccio, Frederic S.; Curchitser, Enrique N.; Kleypas, Joan A.; Powell, Thomas M.

    2016-03-01

    The Spratly Island archipelago is a remote network of coral reefs and islands in the South China Sea that is a likely source of coral larvae to the greater region, but about which little is known. Using a particle-tracking model driven by oceanographic data from the Coral Triangle region, we simulated both spring and fall spawning events of Acropora millepora, a common coral species, over a 46-yr period (1960-2005). Simulated population biology of A. millepora included the acquisition and loss of competency, settlement over appropriate benthic habitat, and mortality based on experimental data. The simulations aimed to provide insights into the connectivity of reefs within the Spratly Islands, the settlement of larvae on reefs of the greater South China Sea, and the potential dispersal range of reef organisms from the Spratly Islands. Results suggest that (1) the Spratly Islands may be a significant source of A. millepora larvae for the Palawan reefs (Philippines) and some of the most isolated reefs of the South China Sea; and (2) the relatively isolated western Spratly Islands have limited source reefs supplying them with larvae and fewer of their larvae successfully settling on other reefs. Examination of particle dispersal without biology (settlement and mortality) suggests that larval connectivity is possible throughout the South China Sea and into the Coral Triangle region. Strong differences in the spring versus fall larval connectivity and dispersal highlight the need for a greater understanding of spawning dynamics of the region. This study confirms that the Spratly Islands are likely an important source of larvae for the South China Sea and Coral Triangle region.

  5. Trends in significant wave height and surface wind speed in the China Seas between 1988 and 2011

    Science.gov (United States)

    Zheng, Chongwei; Zhang, Ren; Shi, Weilai; Li, Xin; Chen, Xuan

    2017-10-01

    Wind and waves are key components of the climate system as they drive air-sea interactions and influence weather systems and atmospheric circulation. In marine environments, understanding surface wind and wave fields and their evolution over time is important for conducting safe and efficient human activities, such as navigation and engineering. This study considers long-term trends in the sea surface wind speed (WS) and significant wave height (SWH) in the China Seas over the period 1988-2011 using the Cross-Calibrated Multi-Platform (CCMP) ocean surface wind product and a 24-year hindcast wave dataset obtained from the WAVEWATCH-III (WW3) wave model forced with CCMP winds. The long-term trends in WS and SWH in the China Seas are analyzed over the past 24 years to provide a reference point from which to assess future climate change and offshore wind and wave energy resource development in the region. Results demonstrate that over the period 1988-2011 in the China Seas: 1) WS and SWH showed a significant increasing trend of 3.38 cm s-1 yr-1 and 1.52 cm yr-1, respectively; 2) there were notable regional differences in the long-term trends of WS and SWH; 3) areas with strong increasing trends were located mainly in the middle of the Tsushima Strait, the northern and southern areas of the Taiwan Strait, and in nearshore regions of the northern South China Sea; and 4) the long-term trend in WS was closely associated with El Niño and a significant increase in the occurrence of gale force winds in the region.

  6. Major components of seawater and hydrothermal plumes in the Okinawa Trough, East China Sea, and Yellow Sea

    Science.gov (United States)

    Zeng, Z.; Rong, K.; Chen, C. T. A.; Wang, X.; Qi, H.

    2017-12-01

    Analyses of the major components of seawater and hydrothermal plumes in hydrothermal fields are essential for an improved understanding of ocean carbonate system, element solubility and redox reactions (e.g., iron and copper). The composition of major components in seawater and hydrothermal plume samples from 118 stations have been investigated in the Okinawa Trough (OT), East China Sea (ECS), and Yellow Sea (YS). At least seven water masses take part in the mixing processes: the Kuroshio water, OT water, ECS water, YS water, Taiwan Strait water, vent fluid and hydrothermal plume water. About 6 - 16 % of the plume water comes from the Kuroshio deep water, 50 - 64% of the hydrothermal plume water comes from the vent fluid in the wet and dry season. In addition, the calculated SHVF (36 and 36.8) and SHPW (35 and 35.8) values are higher than the measured salinity values (34.4) of hydrothermal plumes in the OT. Major elements exhibit linear correlation in seawater (e.g., B3+ and Sr2+) of the OT, the ECS, and the YS. Element ratios (e.g., Sr/Ca, Ca/Cl) in OT water column are similar to that in average seawater, indicating that Sr/Ca and Ca/Cl ratios might be a useful proxy for chemical properties of seawater. Furthermore, from the southern and middle OT to the northern OT, ECS, and YS, the salinity, potential density, Cl/salinity ratio of seawater tend to decrease. The positive correlations between major components (e.g., SO42-, Cl-), physical properties (e.g., salinity, temperature, potential density) and current (velocity) in the seawater column suggests that the physical and chemical properties of seawater in the OT are affected by input of the Kuroshio current. In the Iheya North knoll, Clam, Yonaguni Knoll IV, and Tangyin hydrothermal fields of the OT, anomalous layers of seawater in the water column have higher Ca/SO42-, Mn/Mg ratios and higher optical anomalies than other layers, suggesting that the chemical variations of hydrothermal plumes result in the

  7. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from RYOFU MARU in the Bismarck Sea, East China Sea and others from 1989-11-17 to 1995-03-07 (NODC Accession 0116982)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116982 includes Surface underway data collected from RYOFU MARU in the Bismarck Sea, East China Sea (Tung Hai), North Pacific Ocean, Philippine Sea,...

  8. Image of a subsurface current core in the southern South China Sea

    Directory of Open Access Journals (Sweden)

    Q. S. Tang

    2013-07-01

    Full Text Available A legacy seismic transect acquired on 30 and 31 May 2009 in the southern South China Sea (SCS was reprocessed to reveal the thermohaline structure of the water column. In the study region, a mesoscale subsurface lens with extraordinary features was detected at 113.5° E, 11.5° N. It is centred at 450 m depth, occupies both the subsurface and intermediate water from 250 to 600 m, and has an intersection diameter of around 60 km. The simulated results from Hybrid Coordinate Ocean Model reveal an eddy-induced subsurface current running southwestward along the deep basin edge and suggest that the imaged lens is a snapshot of the subsurface current core rather than a subsurface eddy.

  9. Sources of new nitrogen in the Vietnamese upwelling region of the South China Sea

    DEFF Research Database (Denmark)

    Bombar, Deniz; Dippner, Joachim W.; Doan, Hai Nhu

    2010-01-01

    In the South China Sea, the southwest monsoon between June and September induces upwelling off the southern central Vietnamese coast. During field campaigns in July 2003 and 2004 we evaluated the importance of nitrate and nitrogen fixation as sources of new nitrogen for phytoplankton primary...... productivity, both in the actual upwelling zone and in the oligotrophic area farther offshore. Complementary to rate measurements of primary productivity, nitrate uptake, and nitrogen fixation, we determined vertical nitrate fluxes by Ekman upwelling (upwelling zone) and turbulent diffusion (offshore waters...... productivity, if Redfield stoichiometry is assumed. In July 2003 upwelling fluxes of 14 ± 2 mmol N m-2 d-1 exceeded N demands, indicating that new production was not fully realized. Diffusive nitrate fluxes in offshore waters were determined in July 2003 and are of the order of 2.3 ± 0.6 mmol N m-2 d-1, based...

  10. A Study on Bottom Friction Coefficient in the Bohai, Yellow, and East China Sea

    Directory of Open Access Journals (Sweden)

    Daosheng Wang

    2014-01-01

    Full Text Available The adjoint tidal model based on the theory of inverse problem has been applied to investigate the effect of bottom friction coefficient (BFC on the tidal simulation. Using different schemes of BFC containing the constant, different constant in different subdomain, depth-dependent form, and spatial distribution obtained from data assimilation, the M2 constituent in the Bohai, Yellow, and East China Sea (BYECS is simulated by assimilating TOPEX/Poseidon altimeter data, respectively. The simulated result with spatially varying BFC obtained from data assimilation is better than others. Results and analysis of BFC in BYECS indicate that spatially varying BFC obtained from data assimilation is the best fitted one; meanwhile it could improve the accuracy in the simulation of M2 constituent. Through the analysis of the best fitted one, new empirical formulas of BFC in BYECS are developed with which the commendable simulated results of M2 constituent in BYECS are obtained.

  11. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea.

    Science.gov (United States)

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-06-20

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1-2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs.

  12. Diapycnal Fluxes of Nutrients in an Oligotrophic Oceanic Regime: The South China Sea

    Science.gov (United States)

    Du, Chuanjun; Liu, Zhiyu; Kao, Shuh-Ji; Dai, Minhan

    2017-11-01

    Nutrients from depth have been hypothesized as a primary source of new nutrients that sustain new productivity in oligotrophic oceans; however, the flux is challenging to quantify. Here we show for a first time in the oligotrophic South China Sea an extremely low diapycnal dissolved inorganic nitrogen (DIN) flux as 1.8 × 10-4 mmol m-2 d-1 in the nutrient-depleted layer (NDL) above the nutricline, where other nutrient supplies sustain the new production. Here higher phosphate and silicate fluxes relative to DIN than Redfield stoichiometry further indicate N-limited biological productivity and additional removal of DIN by diatoms. Below the NDL across the nutricline to the base of euphotic zone, termed as nutrient replete layer, the DIN flux is three orders of magnitude larger and sufficient in supporting the export production therein. Here higher DIC flux relative to DIN than Redfield stoichiometry further infers DIC excess in the upper ocean.

  13. Free polyamine content during algal bloom succession in the East China Sea in spring 2010

    Science.gov (United States)

    Liu, Yan; Zhao, Weihong; Li, Caiyan; Miao, Hui

    2017-01-01

    We measured the concentrations and distribution of major polyamines (spermine, putrescine and spermidine) in seawater during successive spring algal blooms in an area of frequent harmful blooms in the East China Sea. Spermine, putrescine, and spermidine concentrations were analyzed by high performance liquid chromatography and ranged from 1-64, 7-81, and 0-19 nmol/L. Spermine was present at the highest concentrations, followed by putrescine and spermidine. In late April, when a diatom bloom dominated by Skeletonema costatum dispersed, polyamine concentrations increased, presumably as a result of diatom decomposition. In early May, when a dinoflagellate bloom dominated by Prorocentrum donghaiense occurred, the polyamine concentration decreased from the level seen in late April. The abundant polyamines that decomposed and were released during the diatom bloom in late April may have promoted the growth of P. donghaiense, resulting in its dominance.

  14. Chemical Constituents of the Sponge Mycale Sp ecies from South China Sea

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhou

    2013-03-01

    Full Text Available Chemical investigation of the sponge Mycale species from the South China Sea afforded eleven known compounds, henicosanoic acid methyl ester (1 , hexadecyl ethers of glycerol ( 2 , N-docosanoyl-D-erythro-(2S,3R-16-methyl-heptadecasphing-4(E-enine ( 3 , dibutyl phthalate ( 4 , cholesterol ( 5 , 5α,8α-epidioxycholest-6,22-dien-3β-ol ( 6 , 5-hexadecyl-pyrrole-2-carboxaldehyde ( 7 , benzoic acid ( 8 , 4-hydroxybenzoic acid ( 9 , thymine ( 10 ,and uracil ( 11 . Compounds 1 – 4 , 6 – 9 were obtained from the sponge of the genus Mycale for the first time, and 4 and 6 showed toxicity in the brine shrimp lethality test with the LD 50 values at 2.9 μg/mL and 4. 7 μg/mL, respectively .

  15. The rift architecture and extensional tectonics of the South China Sea

    Science.gov (United States)

    Cameselle, Alejandra L.; Ranero, César R.; Barckhausen, Udo; Franke, Dieter

    2016-04-01

    Non-volcanic rifted continental margins are classically described as the product of lithospheric stretching and breakup leading to mantle exhumation, and subsequent seafloor spreading. However, recent studies question this model and indicate a wider range of structural evolutions, that challenge the existing model (e.g. Australia-Antarctic Rift System (Direen et al. 2007, 2011); the Tyrrhenian basin (Prada et al., 2014) or the South China Sea (Cameselle et al. 2015)). Rifting in the South China Sea developed from a series of extensional events, from early Eocene to Late Oligocene, resulting in a V-shape oceanic basin affected by the occurrence of several spreading centers, ridges, transform faults and post-spreading volcanism. In recent years, this marginal basin - the largest in East Asia - has increasingly become one of the key sites for the study of rifting and continental break-up. Its relative small size - compared to many classic, Atlantic-type continental margin settings - allows to easily match conjugated rifted margins and its relative youth promotes the preservation of its original nature. To examine the rifting evolution of the South China Sea, we have reprocessed with modern algorithms multichannel seismic profiles acquired during Sonne49 and BGR84 cruises across the three major subbasins: NW, SW and East subbasins. State-of-the-art of processing techniques have been used to increase the signal to noise ratio, including Tau-P and Wiener predictive deconvolution, multiple attenuation by both radon filtering and wave-equation-based surface-related multiple elimination (SRME) and time migration. To complement seismic interpretation, available vintage multichannel seismic data have been reprocessed with a post-stack flow, including Wiener deconvolution, FK-filtering, space and time variant band-pass filter and time migration. The improving quality of the seismic images shows a range of features including post-rift and syn-rift sediments, the structure of

  16. A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria.

    Science.gov (United States)

    He, Wen-Fei; Xue, Duo-Qing; Yao, Li-Gong; Li, Jia; Liu, Hai-Li; Guo, Yue-Wei

    2016-01-01

    A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 4.27 ± 0.55 μM, which is comparable with the positive control oleanolic acid (IC50 = 2.63 ± 0.22 μM).

  17. A New 1,4-Diazepine from South China Sea Marine Sponge Callyspongia Species

    Directory of Open Access Journals (Sweden)

    Shi-Hai Xu

    2010-02-01

    Full Text Available A new 1,4-diazepine, callysponine (1, was isolated from a South China Sea Callyspongia sp. marine sponge, together with four known proline-based diketopiperazines: cyclo-(S-Pro-R-Leu (2, cyclo-(S-Pro-R-Val (3, cyclo-(S-Pro-R-Ala (4, andcyclo-(S-Pro-R-Tyr (5. The new structure was determined on the basis of NMR and MS analysis, and the absolute stereochemistry was defined by NOESY spectroscopy and optical rotation. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported in the literature. Callysponine (1 did not inhibit the growth of HepG2 (hepatoma carcinoma cell, A549 (lung carcinoma cell, and HeLa (cervical cancer cell cell lines.

  18. Community composition of picoeukaryotes in the South China Sea during winter

    Science.gov (United States)

    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.

  19. China's Yangtze delta: Geochemical fingerprints reflecting river connection to the sea

    Science.gov (United States)

    Gu, Jiawei; Chen, Jing; Sun, Qianli; Wang, Zhanghua; Wei, Zixin; Chen, Zhongyuan

    2014-12-01

    This study investigates sediment source to sink relating the connection of the Yangtze River to the sea. A sediment borehole (PD) on the river coast, penetrating thick Quaternary sediments and thin sediments of late Pliocene age down to the bedrock, recorded a change in sediment provenance through time. Geochemical elements and magneto-stratigraphy help identify five zones. Zone I (the late Pliocene-the Early Pleistocene), characterized by Pb, Th, U, Ba, La, Ce, Nd, Hf, Y, Zr, Nb and Mn, indicates a local sediment provenance. This means that the study area was a localized sub-basin. Zone II (the Early Pleistocene-the mid-stage of the Early Pleistocene), with remarkable high Fe, K, As and Rb implies a new sediment provenance joining the sub-basin from the middle Yangtze reach after the opening of the Zhenjiang Gorge. Zone III (the mid-stage of Early Pleistocene-the Middle Pleistocene), featured by Ti, V, Cr, Sr, Sc, Cu, Co, Ni, Mg, Ca, Na and P suggests a further extension of sediment provenance to the upper Yangtze basin, where a large block of the E'mei basalt and carbonate occurs. This suggests that the Three Gorges valley linking the upper and middle Yangtze reaches had developed by that time. Zones IV and V (the Middle Pleistocene-the Holocene) have shown their geochemical similarity to Zone III. Discrimination ratio f(Cr, Th), f(La) and f(K, La), a new approach developed for tracing sediment provenance, confirms a basin-wide sediment source through Zones III-V. These together witness a progressive extension of the sediment provenance towards the upper Yangtze basin, corresponding to the long-term tilting effect of the Cenozoic Topographic Reversal of the eastern China continent. The timing of the Yangtze River running through into the East China Sea appears at ca. 1.0-1.2 Ma (bottom of Zone III).

  20. Design of a Data Distribution Core Model for Seafloor Observatories in East China Sea

    Science.gov (United States)

    Chen, H.; Qin, R.; Xu, H.

    2017-12-01

    High loadings of nutrients and pollutants from agriculture, industries and city waste waters are carried by Changjiang (Yangtze) River and transformed into the foodweb in the river freshwater plume. Understanding these transport and transformation processes is essential for the ecosystem protection, fisheries resources management, seafood safety and human health. As Xiaoqushan Seafloor Observatory and Zhujiajian Seafloor Observatory built in East China Sea, it is an opportunity and a new way for the research of Changjiang River plume. Data collected by seafloor observatory should be accessed conveniently by end users in real time or near real time, which can make it play a better role. Therefore, data distribution is one of major issues for seafloor observatory characterized by long term, real time, high resolution and continuous observation. This study describes a Data Distribution core Model for Seafloor Observatories in East China Sea (ESDDM) containing Data Acquisition Module (DAM), Data Interpretation Module (DIM), Data Transmission Module (DTM) and Data Storage Module (DTM), which enables acquiring, interpreting, transmitting and storing various types of data in real time. A Data Distribution Model Makeup Language (DDML) based on XML is designed to enhance the expansibility and flexibility of the system implemented by ESDDM. Network sniffer is used to acquire data by IP address and port number in DAM promising to release the operating pressure of junction boxes. Data interface, core data processing plugins and common libraries consist of DIM helping it interpret data in a hot swapping way. DTM is an external module in ESDDM transmitting designated raw data packets to Secondary Receiver Terminal. The technology of database connection pool used in DSM facilitates the efficiency of large volumes of continuous data storage. Given a successful scenario in Zhujiajian Seafloor Observatory, the protosystem based on ESDDM running up to 1500h provides a reference for

  1. Shelf Clinoforms and Suspended Sediments at the Northern and Western Margin of the South China Sea

    Science.gov (United States)

    Stattegger, K.; Unverricht, D.; Szczucinski, W.; Liu, Z.; Heinrich, C.; Nguyen, T. C.; Lahajnar, N.

    2013-12-01

    Sediment plumes and shelf clinoforms can be traced almost continuously from the Yangtse until the Mekong Delta as a unique morphodynamics feature of the northern and western marginal parts of the South China Sea. Major sediment plumes originate at the mouths of large rivers, namely the Yangtse, Pearl, Red and Mekong Rivers and extend several hundred kilometers in downdrift direction which is governed mainly by the monsoonal system with the prevailing winter-monsoon winds from NE. Outside the zone of influence of these large rivers we find numerous small mountainous rivers between the Yangtse and Pearl Rivers in SE China and between the Red and Mekong Rivers in central Vietnam providing high amounts of detrital sediments as well. Age control provides clear evidence that the shelf clinoforms developed after 8200 calendar years BP together with a re-organization of the coastal zone and the onset of major modern river deltas after the last phase of accelerated sea-level rise in the Early Holocene, 9000 - 8200 calendar years BP. For the last century 210-Pb activity profiles reveal complex sedimentary processes with event deposition and frequent erosion and re-deposition with average accumulation rates up to 1.5 cm/yr. Suspended sediment contents (SSC) were measured on the Vietnam Shelf. Key regions like the Gulf of Tonkin and the Mekong delta show a strong monsoonal signal as well as a strong tidal signal in the inter-monsoonal period by significant areas of SSCs greater than 25 μl/l even in the inter-monsoonal season. Suspended sediments exhibit distinct seasonal variability while the deposits of shelf clinoforms reflect the average long-term accumulation patterns of terrigenous sediments sometimes winnowed by marine sedimentation and/or masked by bioturbation.

  2. Assessment on vulnerability of coastal wetlands to sea level rise in the Yangtze Estuary, China

    Science.gov (United States)

    Cui, L.; Ge, Z.; Zhang, L.

    2013-12-01

    The Yangtze Delta in China is vital economic hubs in terms of settlement, industry, agriculture, trade and tourism as well as of great environmental significance. In recent decades, the prospect of climate change, in particular sea level rise and its effects on low lying coastal areas have generated worldwide attention to coastal ecosystems. Coastal wetlands, as important parts of coastal ecosystem, are particularly sensitive to sea level rise. To study the responses of coastal wetlands to climate change, assess the impacts of climate change on coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisites for securing the coastal zone ecosystems. In this study, taking the coastal wetlands in the Yangtze Estuary as a case study, the potential impacts of sea-level rise to coastal wetlands habitat were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model. The key indicators, such as the sea-level rise rate, subsidence rate, elevation, daily inundation duration of habitat and sedimentation rate, were selected to build a vulnerability assessment system according to the IPCC definition of vulnerability, i.e. the aspects of exposure, sensitivity and adaptation. A quantitatively spatial assessment method on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability. The vulnerability assessment on the coastal wetlands in the Yangtze Estuary under the sea level rise rate of the present trend and IPCC A1F1 scenario were performed for three sets of projections of short-term (2030s), mid-term (2050s) and long-term (2100s). The results showed that at the present trend of sea level rise rate of 0.26 cm/a, 92.3 % of the coastal wetlands in the Yangtze Estuary was in the EVI score of 0 in 2030s, i.e. the impact of sea level rise on habitats/species of coastal wetlands was negligible. While 7.4 % and 0.3 % of the coastal wetlands were in the EVI score of

  3. East China Sea Storm Surge Modeling and Visualization System: The Typhoon Soulik Case

    Directory of Open Access Journals (Sweden)

    Zengan Deng

    2014-01-01

    Full Text Available East China Sea (ECS Storm Surge Modeling System (ESSMS is developed based on Regional Ocean Modeling System (ROMS. Case simulation is performed on the Typhoon Soulik, which landed on the coastal region of Fujian Province, China, at 6 pm of July 13, 2013. Modeling results show that the maximum tide level happened at 6 pm, which was also the landing time of Soulik. This accordance may lead to significant storm surge and water level rise in the coastal region. The water level variation induced by high winds of Soulik ranges from −0.1 to 0.15 m. Water level generally increases near the landing place, in particular on the left hand side of the typhoon track. It is calculated that 0.15 m water level rise in this region can cause a submerge increase of ~0.2 km2, which could be catastrophic to the coastal environment and the living. Additionally, a Globe Visualization System (GVS is realized on the basis of World Wind to better provide users with the typhoon/storm surge information. The main functions of GVS include data indexing, browsing, analyzing, and visualization. GVS is capable of facilitating the precaution and mitigation of typhoon/storm surge in ESC in combination with ESSMS.

  4. Arctic Sea Ice, Eurasia Snow, and Extreme Winter Haze in China

    Science.gov (United States)

    Zou, Y.; Wang, Y.; Xie, Z.; Zhang, Y.; Koo, J. H.

    2017-12-01

    Eastern China is experiencing more severe haze pollution in winter during recent years. Though the environmental deterioration in this region is usually attributed to the high intensity of anthropogenic emissions and large contributions from secondary aerosol formation, the impact of climate variability is also indispensable given its significant influence on regional weather systems and pollution ventilation. Here we analyzed the air quality related winter meteorological conditions over Eastern China in the last four decades and showed a worsening trend in poor regional air pollutant ventilation. Such variations increased the probability of extreme air pollution events, which is in good agreement with aerosol observations of recent years. We further identified the key circulation pattern that is conducive to the weakening ventilation and investigated the relationship between synoptic circulation changes and multiple climate forcing variables. Both statistical analysis and numerical sensitivity experiments suggested that the poor ventilation condition is linked to boreal cryosphere changes including Arctic sea ice in preceding autumn and Eurasia snowfall in earlier winter. We conducted comprehensive dynamic diagnosis and proposed a physical mechanism to explain the observed and simulated circulation changes. At last, we examined future projections of winter extreme stagnation events based on the CMIP5 projection data.

  5. Particulate nitrogen and phosphorus in the East China Sea and its adjacent Kuroshio waters and evaluation of budgets for the East China Sea Shelf

    Science.gov (United States)

    Zuo, Jiulong; Song, Jinming; Yuan, Huamao; Li, Xuegang; Li, Ning; Duan, Liqin

    2016-12-01

    Nitrogen (N) and phosphorus (P) in suspended particles are important to the cycles of N and P in marine ecosystem. Suspended particles were collected from the East China Sea (ECS) and its adjacent Kuroshio waters to investigate the composing and distribution characteristics of particulate inorganic and organic nitrogen and phosphorus (PIN, PIP, PON and POP, respectively). The particulate N and P concentrations were fairly low in the Kuroshio water but much higher in the ECS water, especially in nearshore waters. PON and PIP were the dominant forms of particulate N and P, with an exception that POP was the major form of particulate P in the Kuroshio upper water. The regime of particulate N and P in the ECS was strongly influenced by riverine input, oceanic input, ocean current and photosynthesis. Among them, PON and POP were mainly from biogenic source, while PIN and PIP were originated from biogenic and external sources. And sedimentation, remineralization and resuspension were important influencing factors for the vertical distributions of particulate N and P. The budgets of particulate N and P for the ECS Shelf during rainy season (May-October) were also evaluated. The total particulate N and P (TPN and TPP) fluxes from oceanic input are respectively 10.99 and 2.49 times of those from riverine input. And oceanic input contains more POP, which is liable to be decomposed into phosphate, than riverine input. Furthermore, particulate nutrients fluxes from photosynthesis are the overriding source of total influxes for the ECS Shelf, accounting for 90.93% of TPN and 89.37% of TPP influxes. As for the photosynthetic fixed N and P, only 6.17% and 7.60% of them can reach the seafloor, while up to 87.73% and 60.06% of them are likely to be remineralized. The POP-rich oceanic input and the intensive photosynthesis and remineralization processes play important roles in the biogeochemical cycles of N and P in the ECS.

  6. Regional air-sea coupled model simulation for two types of extreme heat in North China

    Science.gov (United States)

    Li, Donghuan; Zou, Liwei; Zhou, Tianjun

    2018-03-01

    Extreme heat (EH) over North China (NC) is affected by both large scale circulations and local topography, and could be categorized into foehn favorable and no-foehn types. In this study, the performance of a regional coupled model in simulating EH over NC was examined. The effects of regional air-sea coupling were also investigated by comparing the results with the corresponding atmosphere-alone regional model. On foehn favorable (no-foehn) EH days, a barotropic cyclonic (anticyclonic) anomaly is located to the northeast (northwest) of NC, while anomalous northwesterlies (southeasterlies) prevail over NC in the lower troposphere. In the uncoupled simulation, barotropic anticyclonic bias occurs over China on both foehn favorable and no-foehn EH days, and the northwesterlies in the lower troposphere on foehn favorable EH days are not obvious. These biases are significantly reduced in the regional coupled simulation, especially on foehn favorable EH days with wind anomalies skill scores improving from 0.38 to 0.47, 0.47 to 0.61 and 0.38 to 0.56 for horizontal winds at 250, 500 and 850 hPa, respectively. Compared with the uncoupled simulation, the reproduction of the longitudinal position of Northwest Pacific subtropical high (NPSH) and the spatial pattern of the low-level monsoon flow over East Asia are improved in the coupled simulation. Therefore, the anticyclonic bias over China is obviously reduced, and the proportion of EH days characterized by anticyclonic anomaly is more appropriate. The improvements in the regional coupled model indicate that it is a promising choice for the future projection of EH over NC.

  7. Crustal Stretching Style and Lower Crust Flow of the South China Sea Northern Margin

    Science.gov (United States)

    Bai, Y.; Dong, D.; Runlin, D.

    2017-12-01

    There is a controversy about crustal stretching style of the South China Sea (SCS) northern margin mainly due to considerable uncertainty of stretching factor estimation, for example, as much as 40% of upper crust extension (Walsh et al., 1991) would be lost by seismic profiles due to poor resolution. To discover and understand crustal stretching style and lower crustal flow on the whole, we map the Moho and Conrad geometries based on gravity inversion constrained by deep seismic profiles, then according to the assumption of upper and lower crust initial thickness, upper and lower crust stretching factors are estimated. According to the comparison between upper and lower crust stretching factors, the SCS northern margin could be segmented into three parts, (1) sediment basins where upper crust is stretched more than lower crust, (2) COT regions where lower crust is stretched more than upper crust, (3) other regions where the two layers have similar stretching factors. Stretching factor map shows that lower crust flow happened in both of COT and sediment basin regions where upper crust decouples with lower crust due to high temperature. Pressure contrast by sediment loading in basins and erosion in sediment-source regions will lead to lower crust flow away from sediment sink to source. Decoupled and fractured upper crust is stretched further by sediment loading and the following compensation would result in relatively thick lower crust than upper crust. In COT regions with thin sediment coverage, low-viscosity lower crust is easier to thin in extensional environment, also the lower crust tends to flow away induced by magma upwelling. Therefore, continental crust on the margin is not stretching in a constant way but varies with the tectonic setting changes. This work is supported by National Natural Science Foundation of China (Grant No. 41506055, 41476042) and Fundamental Research Funds for the Central Universities China (No.17CX02003A).

  8. Submarine landslides on the north continental slope of the South China Sea

    Science.gov (United States)

    Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping

    2018-02-01

    Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.

  9. Investigation of antibiotics in mollusks from coastal waters in the Bohai Sea of China

    International Nuclear Information System (INIS)

    Li Wenhui; Shi Yali; Gao Lihong; Liu Jiemin; Cai Yaqi

    2012-01-01

    This study focused on the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides in mollusks from the Bohai Sea of China. 190 samples of eleven species were collected in 2006, 2007 and 2009. Laboratory analyses revealed that antibiotics were widely distributed in the mollusks with quinolones as the major compounds with concentrations of 0.71∼1575.10 μg/kg, which were up to two orders of magnitude higher than those of sulfonamides (0∼76.75 μg/kg) and macrolides (0∼36.21 μg/kg). The contents of quinolones and macrolides did not show significant changes from 2006, 2007 to 2009, while sulfonamides decreased significantly from 2006 to 2009. Compared with other sites, the city of Dalian was more polluted with quinolones, while Beidaihe was more contaminated with erythromycin and sulfapyridine. In addition, Mactra veneriformis and Meretrix merehjgntrix Linnaeus contained higher concentrations of quinolones and sulfamonomethoxine, while Mytilus edulis had higher levels of erythromycin and sulfapyridine. - Highlights: ► Antibiotics widely existed in the mollusks from the Bohai Sea. ► Quinolones were the major antibiotics in the mollusks. ► The concentrations of sulfonamides decreased from 2006 to 2009. - Antibiotics were widely distributed in the mollusks with quinolones as the major compounds.

  10. Prediction for potential landslide zones using seismic amplitude in Liwan gas field, northern South China Sea

    Science.gov (United States)

    Li, Xishuang; Liu, Baohua; Liu, Lejun; Zheng, Jiewen; Zhou, Songwang; Zhou, Qingjie

    2017-12-01

    The Liwan (Lw) gas field located in the northern slope of the South China Sea (SCS) is extremely complex for its sea-floor topograghy, which is a huge challenge for the safety of subsea facilities. It is economically impractical to obtain parameters for risk assessment of slope stability through a large amount of sampling over the whole field. The linkage between soil shear strength and seabed peak amplitude derived from 2D/3D seismic data is helpful for understanding the regional slope-instability risk. In this paper, the relationships among seabed peak, acoustic impedance and shear strength of shallow soil in the study area were discussed based on statistical analysis results. We obtained a similar relationship to that obtained in other deep-water areas. There is a positive correlation between seabed peak amplitude and acoustic impedance and an exponential relationship between acoustic impedance and shear strength of sediment. The acoustic impedance is the key factor linking the seismic amplitude and shear strength. Infinite slope stability analysis results indicate the areas have a high potential of shallow landslide on slopes exceeding 15° when the thickness of loose sediments exceeds 8 m in the Lw gas field. Our prediction shows that they are mainly located in the heads and walls of submarine canyons.

  11. Can Asian Dust Trigger Phytoplankton Blooms in the Oligotrophic Northern South China Sea?

    Science.gov (United States)

    Wang, Sheng Hsiang; Hsu, Nai-Yung Christina; Tsay, Si-Chee; Lin, Neng-Huei; Sayer, Andrew M.; Huang, Shih-Jen; Lau, William K. M.

    2012-01-01

    Satellite data estimate a high dust deposition flux (approximately 18 g m(exp-2 a(exp-1) into the northern South China Sea (SCS). However, observational evidence concerning any biological response to dust fertilization is sparse. In this study, we combined long-term aerosol and chlorophyll-a (Chl-a) measurements from satellite sensors (MODIS and SeaWiFS) with a 16-year record of dust events from surface PM10 observations to investigate dust transport, flux, and the changes in Chl-a concentration over the northern SCS. Our result revealed that readily identifiable strong dust events over this region, although relatively rare (6 cases since 1994) and accounting for only a small proportion of the total dust deposition (approximately 0.28 g m(exp-2 a(exp-1), do occur and could significantly enhance phytoplankton blooms. Following such events, the Chl-a concentration increased up to 4-fold, and generally doubled the springtime background value (0.15 mg m(exp-3). We suggest these heavy dust events contain readily bioavailable iron and enhance the phytoplankton growth in the oligotrophic northern SCS.

  12. Tidal dynamics and mangrove carbon sequestration during the Oligo–Miocene in the South China Sea

    Science.gov (United States)

    Collins, Daniel S.; Avdis, Alexandros; Allison, Peter A.; Johnson, Howard D.; Hill, Jon; Piggott, Matthew D.; Hassan, Meor H. Amir; Damit, Abdul Razak

    2017-01-01

    Modern mangroves are among the most carbon-rich biomes on Earth, but their long-term (≥106 years) impact on the global carbon cycle is unknown. The extent, productivity and preservation of mangroves are controlled by the interplay of tectonics, global sea level and sedimentation, including tide, wave and fluvial processes. The impact of these processes on mangrove-bearing successions in the Oligo–Miocene of the South China Sea (SCS) is evaluated herein. Palaeogeographic reconstructions, palaeotidal modelling and facies analysis suggest that elevated tidal range and bed shear stress optimized mangrove development along tide-influenced tropical coastlines. Preservation of mangrove organic carbon (OC) was promoted by high tectonic subsidence and fluvial sediment supply. Lithospheric storage of OC in peripheral SCS basins potentially exceeded 4,000 Gt (equivalent to 2,000 p.p.m. of atmospheric CO2). These results highlight the crucial impact of tectonic and oceanographic processes on mangrove OC sequestration within the global carbon cycle on geological timescales. PMID:28643789

  13. Pyrosequencing reveals diverse microbial community associated with the zoanthid Palythoa australiae from the South China Sea.

    Science.gov (United States)

    Sun, Wei; Zhang, Fengli; He, Liming; Li, Zhiyong

    2014-05-01

    Diverse sessile organisms inhabit the coral reef ecosystems, including corals, sponges, and sea anemones. In the past decades, scleractinian corals (Cnidaria, Anthozoa, Scleractinia) and their associated microorganisms have attracted much attention. Zoanthids (Cnidaria, Anthozoa, Zoanthidea) are commonly found in coral reefs. However, little is known about the community structure of zoanthid-associated microbiota. In this study, the microbial community associated with the zoanthid Palythoa australiae in the South China Sea was investigated by 454 pyrosequencing. As a result, 2,353 bacterial, 583 archaeal, and 36 eukaryotic microbial ribotypes were detected, respectively. A total of 22 bacterial phyla (16 formally described phyla and six candidate phyla) were recovered. Proteobacteria was the most abundant group, followed by Chloroflexi and Actinobacteria. High-abundance Rhizobiales and diverse Chloroflexi were observed in the bacterial community. The archaeal population was composed of Crenarchaeota and Euryarchaeota, with Marine Group I as the dominant lineage. In particular, Candidatus Nitrosopumilus dominated the archaeal community. Besides bacteria and archaea, the zoanthid harbored eukaryotic microorganisms including fungi and algae though their diversity was very low. This study provided the first insights into the microbial community associated with P. australiae by 454 pyrosequencing, consequently laid a basis for the understanding of the association of P. australiae-microbes symbioses.

  14. Acoustic impedance properties of seafloor sediments off the coast of Southeastern Hainan, South China Sea

    Science.gov (United States)

    Hou, Zhengyu; Chen, Zhong; Wang, Jingqiang; Zheng, Xufeng; Yan, Wen; Tian, Yuhang; Luo, Yun

    2018-04-01

    Geoacoustic parameters are essential inputs to sediment wave propagation theories and are vital to underwater acoustic environment and explorations of the sea bottom. In this study, 21 seafloor sediment samples were collected off the coast of southeastern Hainan in the South China Sea. The sound speed was measured using a portable WSD-3 digital sonic instrument and the coaxial differential distance measurement method. Based on the measured sound speed and physical properties, the acoustic impedance and the pore-water-independent index of impedance (IOI) were calculated in this study. Similar to the sound speed, the IOI values are closely related to the sediment physical properties and change gradually from the northwest to the southeast. The relations between IOI and physical properties were studied and compared to the relations between the sound speed and physical properties. IOI is better correlated to physical properties than sound speed. This study also uses an error norm method to analyze the sensitivity of IOI to the physical parameters in the double-parameter equations and finds that the most influential physical parameters are as follows: wet bulk density > porosity > clay content > mean particle size.

  15. Tidal dynamics and mangrove carbon sequestration during the Oligo-Miocene in the South China Sea

    Science.gov (United States)

    Collins, Daniel S.; Avdis, Alexandros; Allison, Peter A.; Johnson, Howard D.; Hill, Jon; Piggott, Matthew D.; Hassan, Meor H. Amir; Damit, Abdul Razak

    2017-06-01

    Modern mangroves are among the most carbon-rich biomes on Earth, but their long-term (>=106 years) impact on the global carbon cycle is unknown. The extent, productivity and preservation of mangroves are controlled by the interplay of tectonics, global sea level and sedimentation, including tide, wave and fluvial processes. The impact of these processes on mangrove-bearing successions in the Oligo-Miocene of the South China Sea (SCS) is evaluated herein. Palaeogeographic reconstructions, palaeotidal modelling and facies analysis suggest that elevated tidal range and bed shear stress optimized mangrove development along tide-influenced tropical coastlines. Preservation of mangrove organic carbon (OC) was promoted by high tectonic subsidence and fluvial sediment supply. Lithospheric storage of OC in peripheral SCS basins potentially exceeded 4,000 Gt (equivalent to 2,000 p.p.m. of atmospheric CO2). These results highlight the crucial impact of tectonic and oceanographic processes on mangrove OC sequestration within the global carbon cycle on geological timescales.

  16. Microbial diversity in cold seep sediments from the northern South China Sea

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    2012-05-01

    Full Text Available South China Sea (SCS is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, “SONNE” 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diversity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abundance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment (wet weight. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diversity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.

  17. Sea experiments of the Underway Conductivity-Temperature-Depth prototype made in China

    Science.gov (United States)

    Song, Xiangzhou; Li, Hui; Lin, Xiaopei; Chen, Xueen; Guo, Xinshun; Tian, Jiwei

    2009-12-01

    A new instrument for upper ocean survey, namely the UCTD (Underway Conductivity-Temperature-Depth), which combines some of the advantages of other underway instruments, is introduced in this paper. The Introduction section presents a description of the construction and function of the UCTD, and the experiments conducted in the South China Sea on board the R/V Dong Fang Hong 2 in July 2007 and August 2008. The UCTD system, with pressure and temperature sensors in the probe, is conveniently portable, cost-effective and environment-friendly. It is hopefully suitable for future cruises. An intercomparison based on regressing with the experiment temperature data from both SeaBird plus911 CTD and the UCTD showed that the standard deviation is 0.88°C and the correlation coefficient is 0.96, achieving the goals set for the current oceanography uses. In the hydrodynamic experiments, the descending velocities and depths were calculated for different ship speeds. A pulling test was designed with a tensiometer to measure the magnitude of the pull. The maximal tension of the line was found to be 66.2 kg, which is far lower than the bearing limit of the Hollow Spectra line. Finally, some improvement suggestions are put forward for future experiments and production.

  18. The influence of ENSO on an oceanic eddy pair in the South China Sea

    Science.gov (United States)

    Chu, Xiaoqing; Dong, Changming; Qi, Yiquan

    2017-03-01

    An eddy pair off the Vietnam coast is one of the most important features of the summertime South China Sea circulation. Its variability is of interest due to its profound impact on regional climate, ecosystems, biological processes, and fisheries. This study examines the influence of the El Niño-Southern Oscillation (ENSO), a basin-scale climatic mode, on the interannual variability of this regional eddy pair using satellite observational data and historical hydrographic measurements. Over the last three decades, the eddy pair strengthened in 1994 and 2002, and weakened in 2006, 2007, and 2008. It was absent in 1988, 1995, 1998, and 2010, coinciding with strong El Nino-to-La Nina transitions. Composite analyses showed that the strong transition events of ENSO led to radical changes in the summer monsoon, through the forcing of a unique sea surface temperature anomaly structure over the tropical Indo-Pacific basin. With weaker zonal wind, a more northward wind direction, and the disappearance of a pair of positive and negative wind stress curls, the eastward current jet turns northward along the Vietnam coast and the eddy pair disappears.

  19. Impact of atmospheric wet deposition on phytoplankton community structure in the South China Sea

    Science.gov (United States)

    Cui, Dong-Yang; Wang, Jiang-Tao; Tan, Li-Ju; Dong, Ze-Yi

    2016-05-01

    The South China Sea (SCS), which is the largest marginal sea in East Asia, plays a significant role in regional climate change. However, research on the phytoplankton community structure (PCS) response to atmospheric wet deposition remains inadequate. In this study, field incubation experiments were performed to survey the impact of atmospheric wet deposition on the PCS in the SCS in December 2013. Results indicate that the mean dissolved inorganic nitrogen/dissolved inorganic phosphorous (DIN/DIP) ratio in rainwater was 136, which was higher than that in seawater. Under low initial nutrient concentrations, rainwater inputs not only significantly increased total chlorophyll a (Chl a) concentrations but also potentially altered the PCS. The total Chl a concentration increased 1.7-, 1.9-, and 1.6-fold; microphytoplankton increased 2.6-, 3.2-, and 1.7-fold with respect to their initial values in the 5%, 10% addition, and 10% addition (filtered) treatment samples, respectively. Finally, microphytoplankton contributed 61% to the total Chl a concentration in 10% addition treatment samples. Differences in the nutrients induced by atmospheric wet deposition resulted in a shift in the advantage from picophytoplankton to microphytoplankton. Diatoms became the predominant species, accounting for 55% of the total abundance after rainwater addition.

  20. Five Dragons Stirring Up the Sea: Challenge and Opportunity in China’s Improving Maritime Enforcement Capabilities (China Maritime Study, Number 5)

    Science.gov (United States)

    2010-04-01

    Chinese fishing industry has been plagued in the last decade by the environmental devastation wrought by overfishing. While growth in aquaculture has...ish fish stocks. A “zero growth ” plan for the fishing fleet was initiated in 1999. By 2004, eight thousand fishing vessels had been scrapped, and...occasions. In March, Unicorn Ace, with a crew of nineteen Chinese citizens, sank in the South China Sea. The Hong Kong Rescue Service, querying the

  1. Deep-water carbonate dissolution in the northern South China Sea during Marine Isotope Stage 3

    Directory of Open Access Journals (Sweden)

    Na Wang

    2016-01-01

    Full Text Available The production, transportation, deposition, and dissolution of carbonate profoundly form part of the global carbon cycle and affect the amount and distribution of dissolved inorganic carbon (DIC and alkalinity (ALK, which drive atmospheric CO2 changes during glacial/interglacial cycles. These processes may provide significant clues for better understanding of the mechanisms that control the global climate system. In this study, we calculate and analyze the foraminiferal dissolution index (FDX and the fragmentation ratios of planktonic foraminifera for the 60–25 ka B.P. time-span, based on samples from Core 17924 and ODP Site 1144 in the northeastern South China Sea (SCS, so as to reconstruct the deep-water carbonate dissolution during Marine Isotope Stage 3 (MIS 3. Our analysis shows that the dissolution of carbonate increases gradually in Core 17924, whereas it remains stable at ODP Site 1144. This difference is caused by the deep-sea carbonate ion concentration ([CO32−] that affected the dissolution in Core 17924 where the depth of 3440 m is below the saturation horizon. However, the depth of ODP Site 1144 is 2037 m, which is above the lysocline where the water is always saturated with calcium carbonate; the dissolution is therefore less dependent of chemical changes of the seawater. The combined effect of the productivity and the deep-water chemical evolution may decrease deep-water [CO32−] and accelerate carbonate dissolution. The fall of the sea-level increased the input of DIC and ALK to the deep ocean and deepened the carbonate saturation depth, which caused an increase of the deep-water [CO32−]. The elevated [CO32−] partially neutralized the reduced [CO32−] contributed by remineralization of organic matter and slowdown of thermohaline. These consequently are the fundamental reasons for the difference in dissolution rate between these two sites.

  2. Fluxes of particulate organic carbon in the East China Sea in summer

    Directory of Open Access Journals (Sweden)

    C.-C. Hung

    2013-10-01

    Full Text Available To understand carbon cycling in marginal seas better, particulate organic carbon (POC concentrations, POC fluxes and primary production (PP were measured in the East China Sea (ECS in summer 2007. Higher concentrations of POC were observed in the inner shelf, and lower POC values were found in the outer shelf. Similar to POC concentrations, elevated uncorrected POC fluxes (720–7300 mg C m−2 d−1 were found in the inner shelf, and lower POC fluxes (80–150 mg C m−2 d−1 were in the outer shelf, respectively. PP values (~ 340–3380 mg C m−2 d−1 had analogous distribution patterns to POC fluxes, while some of PP values were significantly lower than POC fluxes, suggesting that contributions of resuspended particles to POC fluxes need to be appropriately corrected. A vertical mixing model was used to correct effects of bottom sediment resuspension, and the lowest and highest corrected POC fluxes were in the outer shelf (58 ± 33 mg C m−2 d−1 and the inner shelf (785 ± 438 mg C m−2 d−1, respectively. The corrected POC fluxes (486 to 785 mg C m−2 d−1 in the inner shelf could be the minimum value because we could not exactly distinguish the effect of POC flux from Changjiang influence with turbid waters. The results suggest that 27–93% of the POC flux in the ECS might be from the contribution of resuspension of bottom sediments rather than from the actual biogenic carbon sinking flux. While the vertical mixing model is not a perfect model to solve sediment resuspension because it ignores biological degradation of sinking particles, Changjiang plume (or terrestrial inputs and lateral transport, it makes significant progress in both correcting the resuspension problem and in assessing a reasonable quantitative estimate of POC flux in a marginal sea.

  3. Aerial observation of nitrogen compounds over the East China Sea in 2009 and 2010

    Science.gov (United States)

    Fujiwara, Hiroshi; Sadanaga, Yasuhiro; Urata, Junki; Masui, Yoshihiko; Bandow, Hiroshi; Ikeda, Keisuke; Hanaoka, Sayuri; Watanabe, Izumi; Arakaki, Takemitsu; Kato, Shungo; Kajii, Yoshizumi; Zhang, Daizhou; Hara, Kazutaka; Fujimoto, Toshiyuki; Seto, Takafumi; Okuyama, Kikuo; Ogi, Takashi; Takami, Akinori; Shimizu, Atsushi; Hatakeyama, Shiro

    2014-11-01

    Aerial observations of atmospheric pollutants were made over the East China Sea to analyze the transport of air pollutants, especially nitrogen oxides, from East Asia. Three flights each were conducted in October 2009 (autumn) and December 2010 (winter). Onboard measurements of gaseous total odd nitrogen species, gaseous nitric acid (HNO3(g)), O3, SO2, CO and black carbon were made and particles were collected on filters for ionic and metal component analyses. The NO3-(p)/T.NO3 (T.NO3 = HNO3(g) + NO3-(p); NO3-(p) indicates particulate nitrate) ratios were less than 0.5 in most cases. Exceptions were 17 October and 11 December, when high concentrations of dust particles (Kosa) were transported. The average T.NO3/NOy (NOy indicates total odd nitrogen species) ratio in winter was 0.59, and that in autumn was 0.71. In addition, positive and negative correlations between NOy - T.NO3 and ozone were observed in autumn and winter, respectively. These results indicate that the main components of NOy - T.NO3 are NOx and its descendant photochemical products, such as peroxyacyl nitrates and alkyl nitrates, in winter and autumn, respectively. Ratios of Na+ to Cl- + NO3- in particles were close to the seawater ratio for observations in both autumn and winter, save for the Kosa events. The main NO3-(p) formation process was the reaction of HNO3(g) with sea salt aerosols during autumn and winter. On the other hand, NO3-(p) was generated by the reaction of HNO3(g) with dust particles and sea salt during the Kosa events. The fraction of NH4NO3 in NO3-(p) was very small.

  4. Seasonal Characteristics and Dynamic Mechanism of the Surface Kuroshio Branch intrusion into the South China Sea

    Science.gov (United States)

    Guo, Jingsong; Zhang, Zhixin; Xia, Changshui; Qiao, Fangli

    2017-04-01

    Using the observational data of the Argos satellite-tracked drifters from 1988 to 2012, we analyzed the surface Kuroshio Branch (KB) intrusion into the South China Sea (SCS). The analysis results are as follows. The surface KB mostly originates from the southern Balintang Channel (SBLTC) and the southern Babuyan Channel (BBYC). It starts in late September, reaches its peak (in terms of both speed and intrusion probability) in December-January and declines at the end of March. The mean speed of the drifters during traversing the Luzon Strait (LS) was 43% faster than that during the two days before entering the LS when the flow originated from the SBLTC, but there was no significant increase in speed when the flow came from the BBYC. The observations showed that in wintertime the monthly-mean sea-level anomalies (SLAs) were positive southwest of Taiwan Island and extended to the northern LS, and were negative northwest of Luzon Island and extended to the southern LS. The SLAs were accompanied by an anticyclonic circulation and a cyclonic circulation, which acted like a pump, forcing a part of the Kuroshio water westward into the SCS, especially for the water originated from the SBLTC. The condition under which the KB forms is solved by the equations of motion. The theoretical results indicate that whether the Kuroshio Surface Water can cross the LS into the SCS depends upon the sea-level gradient at the central LS and the region to the west, as well as the position, velocity and direction of the Kuroshio Surface Water when it enters the LS. Key words: surface Kuroshio Branch, Luzon Strait, dynamic mechanism

  5. The South China Sea Mesoscale Eddy Experiment (S-MEE) and Its Primary Findings

    Science.gov (United States)

    Zhang, Z.; Tian, J.; Zhao, W.; Qiu, B.

    2016-02-01

    South China Sea (SCS), the largest marginal sea in the northwestern Pacific, have strong eddy activities as revealed by both satellite and in situ observations. The 3D structures of the SCS mesoscale eddies and their lifecycles, including the generation and dissipation processes, are, however, still not well understood at present because of the lack of well-designed field observations. In order to address the above two scientific issues (3D structure and lifecycle of SCS mesoscale eddies), the SCS Mesoscale Eddy Experiment (S-MEE for short) was designed and conducted in the period from October 2013 to June 2014. As part of S-MEE, two bottom-anchored subsurface mooring arrays with one consisting of 10 moorings and the other 7 moorings, were deployed along the historical pathway of the mesoscale eddies in the northern SCS. All the moorings were equipped with ADCPs, RCMs, CTDs and temperature chains to make continues measurements of horizontal current velocity and temperature/salinity in the whole water column. During the S-MEE, a total of 5 distinct mesoscale eddies were observed to cross the mooring arrays, among which one anticyclonic and cyclonic eddy pair was fully captured by the mooring arrays. In addition to moored observations, we also conducted two transects across the center of the anticyclonic eddy and made high-resolution hydrographic and turbulent mixing measurements. Based on the data collected by the S-MEE and concurrent satellite-derived observations, we constructed the full-depth 3D structure of the eddy pair and analyzed its generation and dissipation mechanisms. We found that the eddies extend from the surface to the sea bottom and display prominent tilted structures in the vertical. By conducting an eddy energy budget analysis, we further identified that generation of submesoscale motions constitutes the dominant mechanism for the oceanic eddy dissipation.

  6. In Situ Raman Detection of Gas Hydrates Exposed on the Seafloor of the South China Sea

    Science.gov (United States)

    Zhang, Xin; Du, Zengfeng; Luan, Zhendong; Wang, Xiujuan; Xi, Shichuan; Wang, Bing; Li, Lianfu; Lian, Chao; Yan, Jun

    2017-10-01

    Gas hydrates are usually buried in sediments. Here we report the first discovery of gas hydrates exposed on the seafloor of the South China Sea. The in situ chemical compositions and cage structures of these hydrates were measured at the depth of 1,130 m below sea level using a Raman insertion probe (RiP-Gh) that was carried and controlled by a remotely operated vehicle (ROV) Faxian. This in situ analytical technique can avoid the physical and chemical changes associated with the transport of samples from the deep sea to the surface. Natural gas hydrate samples were analyzed at two sites. The in situ spectra suggest that the newly formed hydrate was Structure I but contains a small amount of C3H8 and H2S. Pure gas spectra of CH4, C3H8, and H2S were also observed at the SCS-SGH02 site. These data represent the first in situ proof that free gas can be trapped within the hydrate fabric during rapid hydrate formation. We provide the first in situ confirmation of the hydrate growth model for the early stages of formation of crystalline hydrates in a methane-rich seafloor environment. Our work demonstrates that natural hydrate deposits, particularly those in the early stages of formation, are not monolithic single structures but instead exhibit significant small-scale heterogeneities due to inclusions of free gas and the surrounding seawater, there inclusions also serve as indicators of the likely hydrate formation mechanism. These data also reinforce the importance of correlating visual and in situ measurements when characterizing a sampling site.

  7. Metal concentrations in the mussel Bathymodiolus platifrons from a cold seep in the South China Sea

    Science.gov (United States)

    Wang, Xiaocheng; Li, Chaolun; Zhou, Li

    2017-11-01

    Data regarding the concentration and distribution of various metals in different tissues of mussels from the cold seep is scant. We aimed to quantify the presence of twenty elements (Ca, K, Mg, Sr, Ag, Al, As, Ba, Cd, Co, Cr, Cu, Li, Fe, Mn, Mo, Ni, Pb, V, and Zn) in gills, mantles and shells of Bathymodiolus platifrons, a common mussel species in deep-sea cold seep and hydrothermal vent communities. Specimens of B. platifrons were sampled from a cold seep at the northern continental slope of the South China Sea and the elemental contents in its tissues were quantified. Our findings were compared to data from taxonomically similar species at hydrothermal vents and coastal waters. We found that most elements were significantly enriched in the gills, which could be related to food uptake and the existence of endosymbionts. In shells and mantles, Mn was particularly rich, possibly due to its replacement of Ca in the carbonate structure. A significant positive correlation among Ca, Sr, and Mg was found in both gills and mantles, consistent with relationships observed in vent and littoral mussel species. Concentrations of metals were highest in the new-growth outer edges of shells in comparison to older shell material, which suggests that trace metals have become more abundant in the ambient seawater in recent years. Compared with other deep-sea environments and coastal areas, metal accumulation showed local variability but similar overall patterns of uptake and accumulation, indicating that essential elemental requirements in different mussel species may be similar across taxa. The high bioconcentration factor (BCF) values of Mn and Ag suggest that their particular functions and regulation mechanisms are related to specific adaptations and life cycle processes.

  8. Ibsen's mermaid in China: adapting The lady from the sea for the traditional Yue theatre

    Directory of Open Access Journals (Sweden)

    Terry Siu-han Yip

    2015-02-01

    Full Text Available Ibsen has created Ellida Wangel in The Lady from the Sea as a “mermaid” stranded on land, feeling trapped in her marriage with Dr Wangel and suffocated by her restrictive gender roles as wife and step-mother. The play focuses on Ellida the dying mermaid’s process of individuation as she struggles to seek happiness, freedom and self-fulfilment in life. Through Ellida’s entangled relationship with the Stranger and her husband, Ibsen has created a living “mermaid”, who enables him to explore gender relations, individual freedom and choice, as well as the liberation of the self.             However, when The Lady from the Sea was transposed from Norway to China and adapted for the traditional Chinese theatre, the Chinese Yue theatre in this case, Ellida had undergone drastic changes in order to suit the traditional Yue theatregoers’ expectations and taste, as well as to fit the socio-cultural norm of traditional Yue opera.             Instead of examining those technical alterations such as rearrangement of scenes (Ye, 2011, 20, the use of symbols (Wu, 2011, 80, the setting (Wu, 2011, 78, or theatrical performance and devices (Qing Yun, 2010, 32 adopted in the Chinese operatic adaptation of The Lady from the Sea, this article focuses on the cultural re-presentation of Ellida and the re-constitution of her character, the purpose of which is to make her plausible as a Chinese woman on the traditional Yue stage. A close study of the cultural transformation of Ellida and her re-orientation on the traditional Yue stage adaptation will enable the reader to better understand the Chinese cultural emphasis on didacticism, Confucian morality and propriety in traditional drama and theatre, as well as the difficulties involved in transporting Ibsen’s mermaid to the Chinese traditional Yue stage.

  9. Reconstruction of Monsoon Driven South China Sea Surface Ocean Circulation using Coral Δ14C

    Science.gov (United States)

    Goodkin, N.; Bolton, A.; Karnauskas, K. B.; Hughen, K. A.; Griffin, S.; Druffel, E. R. M.

    2016-12-01

    The need to improve our understanding of annual and decadal climate behavior in the South China Sea is increasingly important, as this region includes the largest population density globally but encompasses few climate records. Here we present a record of annually resolved Δ14C from a coral collected off the coast of Nha Trang, Vietnam (12°12'49.90″N, 109°18'17.51″E), that reveals a significant correlation to regional winter sea level pressure (SLP) and sea surface temperature (SST), and extends back more than 400 years. Coral Δ14C during thermonuclear bomb testing indicates the presence of wet-season (summer) upwelling, demonstrated by low Δ14C values for both baseline and peak values relative to other records in the region (Bolton et al., 2016, Radiocarbon). However, annually resolved pre-bomb Δ14C correlates significantly to regional dry-season (winter) SLP and SST, indicating that annual variability is driven by changes to the East Asian Winter Monsoon (EAWM) and subsequent down-welling at this site. Spectral density is focused at 25, 11.8, 7, 4, and 3.2 years per cycle reflecting a range of influences on surface advection variability including the EAWM (D'Arrigo et al., 2005, GRL) and the El Nino Southern Oscillation (ENSO). Spectral power at all of these frequencies decreases following the Little Ice Age ( 1600-1850?) to today, indicating that wind driven surface advection was more variable when hemispheric temperatures were cooler. Decadal variance in the past 100 years is significantly correlated to variance records of the Arctic Oscillation (AO, Thompson and Wallace, 1989, GRL), suggesting that increasing variance in the EAWM may be tied to increasing variance of the AO during the Little Ice Age and vice versa.

  10. Size Resolved Measurements of Springtime Aerosol Particles over the Northern South China Sea

    Science.gov (United States)

    Atwood, Samuel A.; Reid, Jeffrey S.; Kreidenweis, Sonia M.; Cliff, Stephen S.; Zhao, Yongjing; Lin, Neng-Huei; Tsay, Si-Chee; Chu, Yu-Chi; Westphal, Douglas L.

    2012-01-01

    Large sources of aerosol particles and their precursors are ubiquitous in East Asia. Such sources are known to impact the South China Sea (henceforth SCS), a sometimes heavily polluted region that has been suggested as particularly vulnerable to climate change. To help elucidate springtime aerosol transport into the SCS, an intensive study was performed on the remote Dongsha (aka Pratas) Islands Atoll in spring 2010. As part of this deployment, a Davis Rotating-drum Uniform size-cut Monitor (DRUM) cascade impactor was deployed to collect size-resolved aerosol samples at the surface that were analyzed by X-ray fluorescence for concentrations of selected elements. HYSPLIT backtrajectories indicated that the transport of aerosol observed at the surface at Dongsha was occurring primarily from regions generally to the north and east. This observation was consistent with the apparent persistence of pollution and dust aerosol, along with sea salt, in the ground-based dataset. In contrast to the sea-level observations, modeled aerosol transport suggested that the westerly flow aloft (w700 hPa) transported smoke-laden air toward the site from regions from the south and west. Measured aerosol optical depth at the site was highest during time periods of modeled heavy smoke loadings aloft. These periods did not coincide with elevated aerosol concentrations at the surface, although the model suggested sporadic mixing of this free-tropospheric aerosol to the surface over the SCS. A biomass burning signature was not clearly identified in the surface aerosol composition data, consistent with this aerosol type remaining primarily aloft and not mixing strongly to the surface during the study. Significant vertical wind shear in the region also supports the idea that different source regions lead to varying aerosol impacts in different vertical layers, and suggests the potential for considerable vertical inhomogeneity in the SCS aerosol environment.

  11. Mercury in the marine boundary layer and seawater of the South China Sea: Concentrations, sea/air flux, and implication for land outflow

    Science.gov (United States)

    Fu, Xuewu; Feng, Xinbin; Zhang, Gan; Xu, Weihai; Li, Xiangdong; Yao, Hen; Liang, Peng; Li, Jun; Sommar, Jonas; Yin, Runsheng; Liu, Na

    2010-03-01

    Using R/V Shiyan 3 as a sampling platform, measurements of gaseous elemental mercury (GEM), surface seawater total mercury (THg), methyl mercury (MeHg), and dissolved gaseous mercury (DGM) were carried out above and in the South China Sea (SCS). Measurements were collected for 2 weeks (10 to 28 August 2007) during an oceanographic expedition, which circumnavigated the northern SCS from Guangzhou (Canton), Hainan Inland, the Philippines, and back to Guangzhou. GEM concentrations over the northern SCS ranged from 1.04 to 6.75 ng m-3 (mean: 2.62 ng m-3, median: 2.24 ng m-3). The spatial distribution of GEM was characterized by elevated concentrations near the coastal sites adjacent to mainland China and lower concentrations at stations in the open sea. Trajectory analysis revealed that high concentrations of GEM were generally related to air masses from south China and the Indochina peninsula, while lower concentrations of GEM were related to air masses from the open sea area, reflecting great Hg emissions from south China and Indochina peninsula. The mean concentrations of THg, MeHg, and DGM in surface seawater were 1.2 ± 0.3 ng L-1, 0.12 ± 0.05 ng L-1, and 36.5 ± 14.9 pg L-1, respectively. In general, THg and MeHg levels in the northern SCS were higher compared to results reported from most other oceans/seas. Elevated THg levels in the study area were likely attributed to significant Hg delivery from surrounding areas of the SCS primarily via atmospheric deposition and riverine input, whereas other sources like in situ production by various biotic and abiotic processes may be important for MeHg. Average sea/air flux of Hg in the study area was estimated using a gas exchange method (4.5 ± 3.4 ng m-2 h-1). This value was comparable to those from other coastal areas and generally higher than those from open sea environments, which may be attributed to the reemission of Hg previously transported to this area.

  12. Fish community diversity in the middle continental shelf of the East China Sea

    Science.gov (United States)

    Shan, Xiujuan; Jin, Xianshi; Zhou, Zhipeng; Dai, Fangqun

    2011-11-01

    The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities (e.g., pollution and overfishing). Thus, the restoration and protection of fishery resources have become critical and complex. The stability and balanced structure of the fish community is a basic foundation for the protection of fishery resources. Based on data collected from bottom trawls by the R/V Beidou in continental shelf of the East China Sea in November 2006 and February 2007, changes in the composition and diversity of fish species and functional groups were analyzed. The research area was divided into offshore waters and inshore waters by the two-way indicator species analysis (TWIA). The results showed that the dominant species were different between offshore waters and inshore waters and also varied with the survey time. The most abundant family was Sciaenidae and Teraponidae in November 2006, Sciaenidae, Engraulidae and Triglidae were most abundant in February 2007. The species belonged mainly to mobile piscivores (G6), benthivores/piscivores (G4), benthivores (G3) and planktivores (G1), and the dominant species in November 2006 were commercial species (e.g. Larimichthys polyactis and Trichiurus japonicus), but small-sized species were dominant in February 2007 (e.g., Harpadon nehereus, Benthosema pterotum, Champsodon capensis, and Acropoma japonicum). The species diversity showed a similar trend as the functional group diversity. Stations with higher diversity were mainly distributed in inshore waters in February 2007, whereas higher diversity was found in offshore waters in November 2006. The highest biomass and species number were found in G6 group, followed by the G4, G5 and G1 groups. The distribution of the number of individuals of each functional group showed the opposite trend as that of the biomass distribution. In addition, the size spectra were mainly concentrated around 3-29 cm, and the individual

  13. Transport of the South China Sea subsurface water outflow and its influence on carbon chemistry of Kuroshio waters off southeastern Taiwan

    Science.gov (United States)

    Chou, Wen-Chen; Sheu, David D.; Chen, C. T. Arthur; Wen, Liang-Saw; Yang, Yih; Wei, Ching-Ling

    2007-12-01

    Depth distributions of pH, dissolved oxygen, dissolved inorganic carbon (DIC), total alkalinity (TA), and δ13CDIC in the water column across the Luzon Strait from the South China Sea to the west Philippine Sea were investigated thoroughly to attest whether the South China Sea subsurface water outflow could act like a "shelf pump" to export the carbon from the interior of the South China Sea into the open Pacific. Results show that the outflow is capable of transporting 17.6 ± 9.0 Tg C a-1 in DIC form out from the South China Sea to the western Pacific, a quantity equivalent to ˜35 ± 18% of the annual export production of the entire South China Sea. Furthermore, owing to the input of this South China Sea outflow, the subsurface waters of the Kuroshio Current become enriched in DIC/TA ratio but depleted in δ13CDIC. Such a change in seawater carbon chemistry might further attenuate the capacity of CO2 sequestration and hamper the use of δ13CDIC data as a tracer to estimate anthropogenic CO2 uptake rate in seawaters around the Kuroshio main path. More importantly, since these modifications can make all their ways northward along with the Kuroshio Current, the effect may reach even as far as to the higher-latitude region in the northwestern Pacific.

  14. Dramatic declines in Euphausia pacifica abundance in the East China Sea: response to recent regional climate change.

    Science.gov (United States)

    Xu, Zhao-Li; Zhang, Dong

    2014-03-01

    As with other marine ecosystems around the world, water temperature has been anomalously warm in recent years in the East China Sea. We analyzed historical data to explore the effects of climatic change on the abundance and distribution variation of Euphausia pacifica in the East China Sea (the Changjiang River estuary and adjacent areas). In 1959, the highest abundance occurred in the spring and autumn, and this krill species was still abundant in May 1974; however, its abundance was significantly reduced in 2002, markedly in spring. Euphausia pacifica was the numerically dominant euphausiid in the East China Sea in 1959. Its mean abundance was up to 1.91 ind m(-3) and 1.64 ind/m(3) in 1959 and 1974, respectively; however, this figure decreased to 0.36 ind m(-3) in 2002. Since 2003, the abundances have been near zero in the most years. Both inter-annual (between November 1959 and 2002) and inter-monthly (between May and June 1959) comparisons suggest that E. pacifica has had a temperature-driven northward movement in response to rising sea surface temperature, especially the positive anomalies since 1997. However, E. pacifica did not come back to the previous habitat when temperature became relative cold. Hence additional factors affecting the E. pacifica distribution and abundance need to be investigated in the future study.

  15. Biogeochemical Impact of Long-Range Transported Dust over Northern South China Sea

    Science.gov (United States)

    Tsay, Si-Chee; Wang, S. H.; Hsu, N. C.

    2011-01-01

    Transpacific transport and impact of Asian dust aerosols have been well documented (e.g., results from ACE-Asia and regional follow-on campaigns), but little is known about dust invasion to the South China Sea (SCS). On 19-21 March 2010, a fierce Asian dust storm affected large areas from the Gobi deserts to the West Pacific, including Taiwan and Hong Kong. As a pilot study of the 7-SEAS (Seven South East Asian Studies) in the northern SCS, detailed characteristics of long-range transported dust aerosols were first observed by a comprehensive set of ground-based instruments deployed at the Dongsha islands (20deg42'52" N, 116deg43'51" E). Aerosol measurements such as particle mass concentrations, size distribution, optical properties, hygroscopicity, and vertical profiles help illustrate the evolution of this dust outbreak. Our results indicate that these dust particles were mixed with anthropogenic and marine aerosols, and transported near the surface. Satellite assessment of biogeochemical impact of dust deposition into open oceans is hindered by our current inability in retrieving areal dust properties and ocean colors over an extensive period of time, particularly under the influence of cloudy conditions. In this paper, we analyze the changes of retrieved Chlorophyll-a (Chl-a) concentration over the northern SCS, considered as oligotophic waters in the spring, from long-term SeaWiFS measurements since 1997. Over the past decade, six long-range transported dust events are identified based on spatiotemporal evolutions of PM10 measurements from regional monitoring stations, with the aid of trajectory analysis. Multi-year composites of Chl-a imagery for dust event and non-dust background during March-April are applied to overcome insufficient retrievals of Chl-a due to cloudy environment. Due to anthropogenic modification within a shallow boundary layer off the densely populated and industrial southeast coast of China, the iron ion activation of deliquescent dust

  16. Selected current-use and historic-use pesticides in air and seawater of the Bohai and Yellow Seas, China

    Science.gov (United States)

    Zhong, Guangcai; Tang, Jianhui; Xie, Zhiyong; Möller, Axel; Zhao, Zhen; Sturm, Renate; Chen, Yingjun; Tian, Chongguo; Pan, Xiaohui; Qin, Wei; Zhang, Gan; Ebinghaus, Ralf

    2014-01-01

    Consumption of pesticides in China has increased rapidly in recent years; however, occurrence and fate of current-use pesticides (CUPs) in China coastal waters are poorly understood. Globally banned pesticides, so-called historic-use pesticides (HUPs), are still commonly observed in the environment. In this work, air and surface seawater samples taken from the Bohai and Yellow Seas in May 2012 were analyzed for CUPs including trifluralin, quintozene, chlorothalonil, dicofol, chlorpyrifos, and dacthal, as well as HUPs (hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and endosulfan). CUP profile in both air and seawater samples generally reflected their consumption patterns in China. HUPs in the air and seawater samples were in comparable levels as those of CUPs with high concentrations. α-Endosulfan, dicofol, and chlorothalonil showed strong net deposition likely resulting from their intensive use in recent years, while CUPs with low consumption amount (quintozene and dacthal) were close to equilibrium at most samplings sites. Another CUP with high usage amout (i.e., chlorpyrifos) underwent volatilization possibly due to its longer half-life in seawater than that in air. α-HCH and γ-HCH were close to equilibrium in the Bohai Sea, but mainly underwent net deposition in the Yellow Sea. The net deposition of α-HCH could be attributed to polluted air pulses from the East China identified by air mass back trajectories. β-HCH showed net volatilization in the Bohai Sea, which was driven by its relative enrichment in seawater. HCB either slightly favored net volatilization or was close to equilibrium in the Bohai and Yellow Seas.

  17. Collagen in the spicule organic matrix of the gorgonian Leptogorgia virgulata

    Science.gov (United States)

    Kingsley, R. J.; Tsuzaki, M.; Watabe, N.; Mechanic, G. L.

    1990-01-01

    Decalcification of the calcareous spicules from the gorgonian Leptogorgia virgulata reveals an organic matrix that may be divided into water insoluble and soluble fractions. The insoluble fraction displays characteristics typical of collagen, which is an unusual component of an invertebrate calcium carbonate structure. This matrix fraction exhibits a collagenous amino acid profile and behavior upon SDS-PAGE. Furthermore, the reducible crosslink, dihydroxylysinonorleucine (DHLNL), is detected in this fraction. The composition of the matrix varies seasonally; i.e., the collagenous composition is most prevalent in the summer. These results indicate that the insoluble matrix is a dynamic structure. Potential roles of this matrix in spicule calcification are discussed.

  18. Tsunami hazard from the subduction megathrust of the South China Sea: Part I. Source characterization and the resulting tsunami

    Science.gov (United States)

    Megawati, Kusnowidjaja; Shaw, Felicia; Sieh, Kerry; Huang, Zhenhua; Wu, Tso-Ren; Lin, Yunung; Tan, Soon Keat; Pan, Tso-Chien

    2009-09-01

    The subduction megathrust under the Manila Trench has been accumulating strain over a period of 440 years or more, and could be the source for a giant earthquake of Mw ˜ 9. We present a plausible earthquake rupture model constructed from seismic and geodetic data, together with hydrodynamic simulations of the potential tsunami with COMCOT (COrnell Multi-grid COupled Tsunami model). Results indicate that this megathrust poses a risk of devastating tsunami for the Philippines, southern China, Vietnam and other population centers bordering the South China Sea.

  19. Current meter and other data from FIXED PLATFORMS from East China Sea (Tung Hai) from 1980-06-02 to 1981-11-18 (NODC Accession 8700250)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected from FIXED PLATFORMS in the East China Sea (Tung Hai) from 02 June 1980 to 18 November 1981. Data were collected by the Pacific...

  20. WATER TEMPERATURE and other data from REEVES in the South China Sea from 1990-10-01 to 1990-10-23 (NODC Accession 9000269)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession was collected in South China Sea (Nan Hai) from ship Reeves between October 1-23, 1990. The real time data of water temperature at varying...

  1. An Observational Study of the Kuroshio in the East China Sea: Local, Regional, and Basin-Wide Perspectives on a Western Boundary Current

    National Research Council Canada - National Science Library

    Andres, Magdalena

    2008-01-01

    .... An observational study of the Kuroshio was conducted using data collected in the East China Sea (ECS) north of Okinawa from December 2002 through November 2004 with an array of inverted echo sounders and acoustic Doppler current profilers...

  2. Response of a natural Phytoplankton community from the Qingdao coast (Yellow Sea, China) to variable CO2 levels over a short-term incubation experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Biswas, H.; Jie, J.; Li, Y.; Zhang, G.; Zhu, Z.-Y.; Wu, Y.; Zhang, G.-L.; Li, Y.-W.; Liu, S.M.; Zhang, J.

    phytoplankton community from the Qingdao coast (NW Yellow Sea, China) was studied under different CO2 levels in microcosms. HPLC pigment analysis revealed the presence of diatoms as a dominant microalgal group; however, members of chlorophytes...

  3. Relocation of the Yellow River as revealed by sedimentary isotopic and elemental signals in the East China Sea

    International Nuclear Information System (INIS)

    Yang Weifeng; Chen Min; Li Guangxue; Cao Jianping; Guo, Zhigang; Ma Qiang; Liu Jiang; Yang Junhong

    2009-01-01

    The Yellow River (YR) supplies a large amount of nutrients and fresh water to the northern Chinese marginal seas, and greatly influences the ecosystem and current patterns. The relocation of the YR outlet from the southern Yellow Sea (YS) to the Bohai Sea in 1855 was demonstrated using northern East China Sea (ECS) sediment characteristics. Both isotopic (δ 13 C, δ 15 N) signals and C/N ratios in the organic matter (OM) indicate that prior to 1750, the predominant source of OM to the sediments was terrestrial. The terrestrial influences continuously weakened until 1855, when the YR estuary moved; after 1855, the OM was characterized by oceanic sources. Major elements (Al, Ti, Fe, Mn) and trace elements (Ni, Cr, Cu, Pb) had a much closer association with Malan loess prior to 1855, as >90% of the YR sediment was loess-derived. These results reveal that the relocation of the YR induced significant changes in the current patterns of the northern China Seas in the last 250 years; however, more studies are needed to further examine these linkages.

  4. Current meter components and other data from fixed platforms from the East China Sea (Tung Hai) as part of the United States/Peoples Republic of China Cooperative Study from 03 June 1980 to 04 August 1981 (NODC Accession 8700311)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from fixed platforms from the East China Sea (Tung Hai) from 03 June 1980 to 04 August 1981. Data were collected by the...

  5. First record of a large-scale bloom-causing species Nannochloropsis granulata (Monodopsidaceae, Eustigmatophyceae) in China Sea waters.

    Science.gov (United States)

    Zhang, Xiaodong; Kan, Jinjun; Wang, Jing; Gu, Haifeng; Hu, Jun; Zhao, Yuan; Sun, Jun

    2015-10-01

    Nannochloropsis is an ubiquitous genus, found in diverse aquatic environments including open ocean as well as fresh and brackish water. Recently, large-scale blooms occurred frequently along eutrophic coastal zone from the Bohai Sea to the northern Yellow Sea in China. The cell density reached 10(9) to 10(10)cells per liter during a bloom near Qinhuangdao, Hebei Province. The bloom forming species, a yellow-green microalgae was successfully isolated and cultivated in the laboratory. Microscopic observation indicated that the cells contained simple morphological characteristics with a diameter about 2 μm. Pigment analyses confirmed that the pigment composition of the newly isolated strain BDH02 was similar to that of Nannochloropsis granulata. Phylogenetic analyses of 18S rRNA gene, ITS, and rbcL gene indicated that the strain was closely related to N. granulata. This is the first record of a bloom caused by N. granulata in China.

  6. Planting Flags on the Tide: Sovereignty, Containment, and Conflict Resolution in the East and South China Seas

    Directory of Open Access Journals (Sweden)

    James DeShaw Rae

    2014-06-01

    Full Text Available The rise of China’s economic and military power is transforming global politics while U.S. strategic interests are re-balancing toward Asia. Meanwhile, tensions over maritime boundaries and island claims within the region are punctuated by police and military stand-offs in the East and South China Seas. This paper considers the discourse surrounding the dispute over sovereignty in the South China Sea. It also examines the roles international law, multilateralism, and traditional diplomacy play in the conflict, and how it serves as a test case for China’s future diplomacy and traditional norms of non-interference and a peaceful rise. Finally, the paper suggests pathways toward conflict resolution of the immediate disputes, including de-territorialized and de-nationalized ideas of possession when it applies to contested yet uninhabited maritime frontiers.

  7. Estimating Surface Area of Sponges and Marine Gorgonians as Indicators of Habitat Availability on Caribbean Coral Reefs

    Science.gov (United States)

    Surface area and topographical complexity are fundamental attributes of shallow tropical coral reefs and can be used to estimate habitat for fish and invertebrates. This study presents empirical methods for estimating surface area provided by sponges and gorgonians in the Central...

  8. Distribution and Behaviors of Cd, Cu, and Ni in the East China Sea Surface Water off the Changjiang Estuary

    OpenAIRE

    Kuo-Tung Jiann; Liang-Saw Wen; Gwo-Ching Gong

    2009-01-01

    Trace metal (Cd, Cu, and Ni) dis tri bu tions and be hav iors in sur face waters of the East China Sea continental shelf were investigated during an expeditioncon ducted in June 2004. Dissolved and particulate trace metal con centrations, as well as fractions of dissolved trace metals, fraction ated based on their different chemical affinities to ion exchangers, were determined using ultra-clean techniques and graphite furnace atomic absorption spectrometry (GFAAS). Large variations of dissol...

  9. Antibacterial α-pyrone derivatives from a mangrove-derived fungus Stemphylium sp. 33231 from the South China Sea.

    Science.gov (United States)

    Zhou, Xue-Ming; Zheng, Cai-Juan; Song, Xiao-Ping; Han, Chang-Ri; Chen, Wen-Hao; Chen, Guang-Ying

    2014-05-01

    Two new α-pyrone derivatives, infectopyrones A (1) and B (2), were obtained from the EtOAc extract of the endophytic fungus Stemphylium sp. 33231 isolated from the mangrove Brguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1 and 2 were evaluated for their antibacterial activities, and they had a broad spectrum of antibacterial activity against five terrestrial pathogenic bacteria.

  10. 40Ar/39Ar dating of oceanic plagiogranite: Constraints on the initiation of seafloor spreading in the South China Sea

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Xie Zhenyu

    Full Text Available 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.

  12. A duodecennial national synthesis of antibiotics in China's major rivers and seas (2005-2016).

    Science.gov (United States)

    Li, Si; Shi, Wanzi; Liu, Wei; Li, Huimin; Zhang, Wei; Hu, Jingrun; Ke, Yanchu; Sun, Weiling; Ni, Jinren

    2018-02-15

    The occurrence of 94 antibiotics in water and sediments from seven major rivers and four seas in China during 2005-2016 was reviewed. Twelve antibiotics were most frequently detected in both water and sediment samples, including 3 sulfonamides (SAs), 2 tetracyclines (TCs), 4 fluoroquinolones (FQs), and 3 macrolides (MLs). Their median concentrations were below 100ng/L and 100ng/g in river water and sediments, respectively. The highest median concentrations were found in water (1.30-176ng/L) and sediments (0.15-110ng/g) in the Hai River, due to its larger population density, higher consumption of antibiotics, and lower water flow. The concentrations of TCs and FQs were higher in the Pearl River sediments, due to their extensive use in aquaculture. The Yangtze River showed lower median concentrations of antibiotics in both water (1.33-17.3ng/L) and sediments (0.31-14.8ng/g), resulting from its larger catchment size, and higher precipitation and water flow. The Yellow River exhibited lower median concentrations of antibiotics in sediments (0.04-9.04ng/g), probably due to low organic matter content in sediments and high suspended particle content in water. Organic carbon normalized distribution coefficients (K oc ) of antibiotics were positively correlated with the octanol/water partition coefficients (K ow ) of antibiotics, and the correlation for MLs with a macrocyclic lactone ring was different from that of SAs, FQs, and TCs, likely due to their much larger molecular size. Among China's major rivers, the Hai River had the highest ecotoxicological risk from antibiotics to algae, invertebrate, fish, and plant. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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

  14. Upper Mantle Responses to India-Eurasia Collision in Indochina, Malaysia, and the South China Sea

    Science.gov (United States)

    Hongsresawat, S.; Russo, R. M.

    2016-12-01

    We present new shear wave splitting and splitting intensity measurements from SK(K)S phases recorded at seismic stations of the Malaysian National Seismic Network. These results, in conjunction with results from Tibet and Yunnan provide a basis for testing the degree to which Indochina and South China Sea upper mantle fabrics are responses to India-Eurasia collision. Upper mantle fabrics derived from shear wave splitting measurements in Yunnan and eastern Tibet parallel geodetic surface motions north of 26°N, requiring transmission of tractions from upper mantle depths to surface, or consistent deformation boundary conditions throughout the upper 200 km of crust and mantle. Shear wave splitting fast trends and surface velocities diverge in eastern Yunnan and south of 26°N, indicating development of an asthenospheric layer that decouples crust and upper mantle, or corner flow above the subducted Indo-Burma slab. E-W fast shear wave splitting trends southwest of 26°N/104°E indicate strong gradients in any asthenospheric infiltration. Possible upper mantle flow regimes beneath Indochina include development of olivine b-axis anisotropic symmetry due to high strain and hydrous conditions in the syntaxis/Indo-Burma mantle wedge (i.e., southward flow), development of strong upper mantle corner flow in the Indo-Burma wedge with olivine a-axis anisotropic symmetry (i.e., westward flow), and simple asthenospheric flow due to eastward motion of Sundaland shearing underlying asthenosphere. Further south, shear-wave splitting delay times at Malaysian stations vary from 0.5 seconds on the Malay Peninsula to over 2 seconds at stations on Borneo. Splitting fast trends at Borneo stations and Singapore trend NE-SW, but in northern Peninsular Malaysia, the splitting fast polarization direction is NW-SE, parallel to the trend of the Peninsula. Thus, there is a sharp transition from low delay time and NW-SE fast polarization to high delay times and fast polarization directions that

  15. Element concentrations in cold-water gorgonians and black coral from Azores region

    Science.gov (United States)

    Raimundo, Joana; Vale, Carlos; Caetano, Miguel; Anes, Bárbara; Carreiro-Silva, Marina; Martins, Inês; Matos, Valentina de; Porteiro, Filipe M.

    2013-12-01

    Seamounts are thought to support high biodiversity and special biological communities, including corals. Corals incorporate minor and trace elements and have been suggested as possible bioindicators of their availability in the environment. Forty specimens of five gorgonian species (Alcyonacea) and a black coral (Antipatharia) were collected in 12 sites in the Azores region. Concentrations of Ca, Mg, Cr, Mn, Co, Ni, Cu, Zn, Se, Cd and Pb were determined in skeleton and attached tissue of each individual from each species. Leiopathes sp. had higher Cr, Ni, Se and Pb concentrations than the gorgonians. Enhanced Cu and Cd values were registered in Leiopathes and Acanthogorgia hirsuta. Specimens of A. hirsuta also presented elevated concentrations of Zn and Co. Linear relationships between Cd and Cu, Zn and Se point to response mechanisms in corals, possibly related to the induction of proteins enlarging the capacity to incorporate further quantities of essential elements. Results obtained in this study suggest the existence of an additional source of Cd in waters off Azores Islands associated with natural hydrothermal activities.

  16. Influence of different water masses on planktonic ciliate distribution on the East China Sea shelf

    Science.gov (United States)

    Zhang, Cuixia; Zhang, Wuchang; Ni, Xiaobo; Zhao, Yuan; Huang, Lingfeng; Xiao, Tian

    2015-01-01

    In summer 2006 and winter 2007, ciliate abundance and biomass were investigated in the East China Sea in connection with water masses, frontal zones, dissolved oxygen and chlorophyll a concentrations, and picoplankton and nanoflagellate abundances. In addition, tintinnid ciliates were identified to species based on lorica morphology. There was no significant difference of ciliate abundance and biomass between Changjiang diluted water (CDW) and shelf mixing water (SMW) in the Changjiang river estuary and its adjacent sea in summer, or among the coastal water (CoW), the SMW and the Kuroshio water (KW) on the shelf in winter. The influence of water masses on ciliate distribution was slight, except that distinct increases in ciliate abundance were observed in the vicinity of frontal structures. Most tintinnids were neritic species, with no discrimination between two water masses in the Changjiang river estuary. However, cosmopolitan and warm water species were very mainly restricted to SMW and KW; neritic species were essentially present in CoW and SMW on the continental shelf. Total ciliate biomass was closely correlated with picoplankton biomass in the CDW and KW. Picoeukaryotes and Synechococcus were the potential food source of ciliates. In winter, within KW, nanoflagellates would play a major role in the transfer of organic matter from picoplankton to ciliates in the microbial community within KW. In the low-oxygen and hypoxia area adjacent to the Changjiang estuary where relatively high ciliate abundance and biomass occurred, heterotrophic bacteria would appear to exhibit a potential prey effect on the distribution of bacterivorous aloricated ciliates and nanoflagellates acting as intermediates between bacteria and tintinnids.

  17. Heavy metal contamination in the marine organisms in Yantai coast, northern Yellow Sea of China.

    Science.gov (United States)

    Zhang, Gaosheng; Liu, Dongyan; Wu, Huifeng; Chen, Linlin; Han, Qingxi

    2012-08-01

    The port city of Yantai, in Shandong province China is located on Sishili Bay in the northern Yellow Sea. Intense human activity associated with urban sewage discharge, as well as industrial and maritime activities, have stressed the Sishili Bay coastal ecosystem with anthropogenic pollution. The aim of this study was to measure the levels of heavy metal in the sediment and marine organisms of economic value from various sites within Sishili Bay, and to evaluate the data in relation to the potential health risk on human consumers. For this purpose, sediment and wild shrimps and crab were collected from three areas (a total of 13 sampling sites) of the Yantai coast and analyzed for six heavy metals (Cu, Zn, Cr, Ni, Pb, and As). For comparison, the concentrations of the same heavy metals in seven kinds of mollusks obtained from local aquaculture were also determined. The findings showed that the concentrations of heavy metals in the sediment of Yantai coast followed the order Zn > ≈Cr > Cu ≈ Ni ≈ Pb > As, and all were within the safe levels of national standard. However, the concentrations of the heavy metals varied significantly in the organism samples, indicating the different accumulative abilities of the species sampled. For the wild marine organisms, Pb concentrations in some shrimp and crab samples exceeded the standard limit of seafood safety criteria and As concentrations in all samples were over the limit. Moreover, the As levels in mollusks from aquaculture exceeded the limit of seafood standard criteria. These results indicated that the heavy metal levels in the marine organisms in the studied areas were moderate but unacceptable for As from the view of safety of seafood. Furthermore, it is very necessary and important to further study toxicological and ecological effect of As in the coast of northern Yellow sea to understand the potential for risk to human and environmental health.

  18. Biogeochemistry of Dimethylsulfide, Dimethylsulfoniopropionate, and Acrylic Acid in the Changjiang Estuary and the East China Sea

    Science.gov (United States)

    Wu, Xi; Li, Pei-Feng; Liu, Chun-Ying; Zhang, Hong-Hai; Yang, Gui-Peng; Zhang, Sheng-Hui; Zhu, Mao-Xu

    2017-12-01

    The distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and acrylic acid (AA) were investigated in the Changjiang Estuary during winter (dry season) and summer (wet season) 2014 and in the East China Sea (ECS) during summer 2015. The rates of dissolved DMSP (DMSPd) degradation with DMS and AA production, DMS degradation, and AA degradation in the ECS were also studied. Significant seasonal variations in DMS(P) and AA concentrations were observed in the Changjiang Estuary with higher values during the wet season than during the dry season. The maximum ratio of AA/chlorophyll a (Chl a) occurred at the mouth of the Changjiang Estuary due to the combined effects of production from DMSP and terrestrial inputs from the Changjiang Estuary. The distributions of DMS(P) and AA in the ECS were dramatically influenced by the Kuroshio Current and the upwelling caused by the Taiwan Warm Current. The ratios of DMS(P)/Chl a and AA/Chl a exhibited similar patterns in the surface seawater of the ECS, which indicated that phytoplankton species and biomass might play important roles in controlling the distributions of DMS(P) and AA. In vertical profiles, high values of AA emerged in the upper water column and bottom seawater of the Changjiang Estuary. Meanwhile, the maxima of DMS(P) and AA generally appeared in the surface or euphotic layer, whereas their minima arose in the bottom seawater of the ECS. The degradation rates of DMSPd, DMS, and AA in the inshore waters were higher than those in the open sea.

  19. Model-simulated coastal trapped waves stimulated by typhoon in northwestern South China Sea

    Science.gov (United States)

    Cao, Xuefeng; Shi, Hongyuan; Shi, Maochong; Guo, Peifang; Wu, Lunyu; Ding, Yang; Wang, Lu

    2017-12-01

    In this paper, we apply an unstructured grid coastal ocean model to simulate variations in the sea level and currents forced by two typhoons in the northwestern South China Sea (SCS). The model simulations show distinct differences for the two cases in which the typhoon paths were north and south of the Qiongzhou (QZ) Strait. In both cases, coastal trapped waves (CTWs) are stimulated but their propagation behaviors differ. Model sensitivity simulations suggest the dominant role played by alongshore wind in the eastern SCS (near Shanwei) and southeast of Hainan Island. We also examine the influence of the Leizhou Peninsula by changing the coastline in simulation experiments. Based on our results, we can draw the following conclusions: 1) The CTWs stimulated by the northern typhoon are stronger than the southern CTW. 2) In the two cases, the directions of the current structures of the QZ cross-transect are reversed. The strongest flow cores are both located in the middle-upper area of the strait and the results of our empirical orthogonal function analysis show that the vertical structure is highly barotropic. 3) The simulated CTWs divide into two branches in the QZ Strait for the northern typhoon, and an island trapped wave (ITW) around Hainan Island for the southern typhoon. 4) The Leizhou Peninsula plays a significant role in the distribution of the kinetic energy flux between the two CTW branches. In the presence of the Leizhou Peninsula, the QZ branch has only 39.7 percent of the total energy, whereas that ratio increases to 72.2 percent in its absence.

  20. The influence of episodic flooding on a pelagic ecosystem in the East China Sea

    Science.gov (United States)

    Chen, Chung-Chi; Gong, Gwo-Ching; Chou, Wen-Chen; Chung, Chih-Ching; Hsieh, Chih-Hao; Shiah, Fuh-Kwo; Chiang, Kuo-Ping

    2017-05-01

    This study was designed to determine the effects of flooding on a pelagic ecosystem in the East China Sea (ECS) with a focus on plankton activity and plankton community respiration (CR). In July 2010, a flood occurred in the Changjiang River. As a comparison, a variety of abiotic and biotic parameters were monitored during this flooding event and during a non-flooding period (July 2009). During the flood, the Changjiang diluted water (CDW) zone covered almost two-thirds of the ECS, which was approximately 6 times the area covered during the non-flooding period. The mean nitrate concentration was 3-fold higher during the 2010 flood (6.2 vs. 2.0 µM in 2009). CR was also higher in the 2010 flood: 105.6 mg C m-3 d-1 vs. only 73.2 mg C m-3 d-1 in 2009. The higher CR in 2010 could be attributed to phytoplankton respiration, especially at stations in the CDW zone that were not previously characterized by low sea surface salinity in 2009. In addition, zooplankton (> 330 µm) were another important component contributing to the high CR rate observed during the 2010 flood; this was a period also associated with a significant degree of fCO2 drawdown. These results collectively suggest that the 2010 flood had a significant effect on the carbon balance in the ECS. This effect might become more pronounced in the future, as extreme rainfall and flooding events are predicted to increase in both frequency and magnitude due to climate change.

  1. Offshore Wind Resources Assessment from Multiple Satellite Data and WRF Modeling over South China Sea

    Directory of Open Access Journals (Sweden)

    Rui Chang

    2015-01-01

    Full Text Available Using accurate inputs of wind speed is crucial in wind resource assessment, as predicted power is proportional to the wind speed cubed. This study outlines a methodology for combining multiple ocean satellite winds and winds from WRF simulations in order to acquire the accurate reconstructed offshore winds which can be used for offshore wind resource assessment. First, wind speeds retrieved from Synthetic Aperture Radar (SAR and Scatterometer ASCAT images were validated against in situ measurements from seven coastal meteorological stations in South China Sea (SCS. The wind roses from the Navy Operational Global Atmospheric Prediction System (NOGAPS and ASCAT agree well with these observations from the corresponding in situ measurements. The statistical results comparing in situ wind speed and SAR-based (ASCAT-based wind speed for the whole co-located samples show a standard deviation (SD of 2.09 m/s (1.83 m/s and correlation coefficient of R 0.75 (0.80. When the offshore winds (i.e., winds directed from land to sea are excluded, the comparison results for wind speeds show an improvement of SD and R, indicating that the satellite data are more credible over the open ocean. Meanwhile, the validation of satellite winds against the same co-located mast observations shows a satisfactory level of accuracy which was similar for SAR and ASCAT winds. These satellite winds are then assimilated into the Weather Research and Forecasting (WRF Model by WRF Data Assimilation (WRFDA system. Finally, the wind resource statistics at 100 m height based on the reconstructed winds have been achieved over the study area, which fully combines the offshore wind information from multiple satellite data and numerical model. The findings presented here may be useful in future wind resource assessment based on satellite data.

  2. The effect of typhoon on particulate organic carbon flux in the southern East China Sea

    Directory of Open Access Journals (Sweden)

    C.-C. Hung

    2010-10-01

    Full Text Available Severe tropical storms play an important role in triggering phytoplankton blooms, but the extent to which such storms influence biogenic carbon flux from the euphotic zone is unclear. In 2008, typhoon Fengwong provided a unique opportunity to study the in situ biological responses including phytoplankton blooms and particulate organic carbon fluxes associated with a severe storm in the southern East China Sea (SECS. After passage of the typhoon, the sea surface temperature (SST in the SECS was markedly cooler (∼25 to 26 °C than before typhoon passage (∼28 to 29 °C. The POC flux 5 days after passage of the typhoon was 265 ± 14 mg C m−2 d−1, which was ∼1.7-fold that (140–180 mg C m−2 d−1 recorded during a period (June–August, 2007 when no typhoons occurred. A somewhat smaller but nevertheless significant increase in POC flux (224–225 mg C m−2 d−1 was detected following typhoon Sinlaku which occurred approximately 1 month after typhoon Fengwong, indicating that typhoon events can increase biogenic carbon flux efficiency in the SECS. Remarkably, phytoplankton uptake accounted for only about 5% of the nitrate injected into the euphotic zone by typhoon Fengwong. It is likely that phytoplankton population growth was constrained by a combination of light limitation and grazing pressure. Modeled estimates of new/export production were remarkably consistent with the average of new and export production following typhoon Fengwong. The same model suggested that during non-typhoon conditions approximately half of the export of organic carbon occurs via convective mixing of dissolved organic carbon, a conclusion consistent with earlier work at comparable latitudes in the open ocean.

  3. Longtime variation of phytoplankton in the South China Sea from the perspective of carbon fixation

    Science.gov (United States)

    Li, Teng; Bai, Yan; Chen, Xiaoyan; Zhu, Qiankun; Gong, Fang; Wang, Difeng

    2017-10-01

    The ocean is a huge carbon pool in the earth, and about half of the anthropogenic emissions of carbon dioxide are absorbed by the ocean each year. By converting inorganic carbon into organic carbon, the photosynthesis process of phytoplankton affords an important way for carbon sequestration in the ocean. According to previous researches, primary production (NPP) and the structure of phytoplankton community are important in regulate the efficiency of biological carbon pump. This study examined the spatiotemporal variability of satellite remote sensing derived chlorophyll a concentration (Chla), phytoplankton carbon biomass (Carbon), composition ratio of micro-, nano- and pico- phytoplankton, NPP and integrated particulate organic carbon (IPOC) during 1998-2007 in the South China Sea (SCS). Micro-, nano-phytoplankton and NPP showed similar seasonal variation with highest values in winter (January) (especially in the western ocean of Luzon Strait) and lowest values in summer (July) in SCS. Chla, phytoplankton carbon biomass, and IPOC showed different seasonal trends with one peak values occurred in winter and lowest in spring. Two sampling areas (A, N:17-21°, E:117.5-120° and B, N:12.5-15°, E:112-119°) in SCS were selected based on spatial distribution of the standard deviation of research parameters mentioned above. Compared to Chla, phytoplankton carbon biomass, NPP and IPOC, the interannual changes of phytoplankton community structure were remarkable in the two areas. The fraction of micro- and nano- phytoplankton in SCS tend to rise when La Nina events occur. Our results contribute to an understanding of the response of phytoplankton to climate change in the marginal sea. To quantify the efficiency of biological carbon pump in this area, more attention should be paid to the development of remote sensing algorithms of export NPP (or POC export flux) as well as the regulate mechanism of export NPP.

  4. CONTRIBUTION OF SATELLITE ALTIMETRY DATA IN GEOLOGICAL STRUCTURE RESEARCH IN THE SOUTH CHINA SEA

    Directory of Open Access Journals (Sweden)

    T. D. Tran

    2016-06-01

    Full Text Available The study area is bordered on the East China Sea, the Philippine Sea, and the Australian-Indo plate in the Northeast, in the East and in the South, respectively. It is a large area with the diversely complicated conditions of geological structure. In spite of over the past many years of investigation, marine geological structure in many places have remained poorly understood because of a thick seawater layer as well as of the sensitive conflicts among the countries in the region. In recent years, the satellite altimeter technology allows of enhancement the marine investigation in any area. The ocean surface height is measured by a very accurate radar altimeter mounted on a satellite. Then, that surface can be converted into marine gravity anomaly or bathymetry by using the mathematical model. It is the only way to achieve the data with a uniform resolution in acceptable time and cost. The satellite altimetry data and its variants are essential for understanding marine geological structure. They provide a reliable opportunity to geologists and geophysicists for studying the geological features beneath the ocean floor. Also satellite altimeter data is perfect for planning the more detailed shipboard surveys. Especially, it is more meaningful in the remote or sparsely surveyed regions. In this paper, the authors have effectively used the satellite altimetry and shipboard data in combination. Many geological features, such as seafloor spreading ridges, fault systems, volcanic chains as well as distribution of sedimentary basins are revealed through the 2D, 3D model methods of interpretation of satellite-shipboard-derived data and the others. These results are improved by existing boreholes and seismic data in the study area.

  5. Evaluation and adjustment of altimeter measurement and numerical hindcast in wave height trend estimation in China's coastal seas

    Science.gov (United States)

    Li, Shuiqing; Guan, Shoude; Hou, Yijun; Liu, Yahao; Bi, Fan

    2018-05-01

    A long-term trend of significant wave height (SWH) in China's coastal seas was examined based on three datasets derived from satellite measurements and numerical hindcasts. One set of altimeter data were obtained from the GlobWave, while the other two datasets of numerical hindcasts were obtained from the third-generation wind wave model, WAVEWATCH III, forced by wind fields from the Cross-Calibrated Multi-Platform (CCMP) and NCEP's Climate Forecast System Reanalysis (CFSR). The mean and extreme wave trends were estimated for the period 1992-2010 with respect to the annual mean and the 99th-percentile values of SWH, respectively. The altimeter wave trend estimates feature considerable uncertainties owing to the sparse sampling rate. Furthermore, the extreme wave trend tends to be overestimated because of the increasing sampling rate over time. Numerical wave trends strongly depend on the quality of the wind fields, as the CCMP waves significantly overestimate the wave trend, whereas the CFSR waves tend to underestimate the trend. Corresponding adjustments were applied which effectively improved the trend estimates from the altimeter and numerical data. The adjusted results show generally increasing mean wave trends, while the extreme wave trends are more spatially-varied, from decreasing trends prevailing in the South China Sea to significant increasing trends mainly in the East China Sea.

  6. AIR PRESSURE and Other Data from FIXED PLATFORMS From East China Sea (Tung Hai) and Others from 19750101 to 19841231 (NCEI Accession 8900274)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of Tide observations from Qinhuangdao, Yent'Ai, and Moup'Ing in the Yellow Sea, and Xiamen in the East China Sea for the years 1975 to 1984....

  7. Flux and seasonality of planktonic foraminifera in the Xisha Trough, South China Sea

    Science.gov (United States)

    Xiang, R.; Chen, M.; Wang, D.; Chen, Z.; Yan, W.

    2013-12-01

    The modern correlation between planktonic foraminiferal community dynamics and environmental conditions may provide a basis for establishing paleoclimatic proxies. We studied planktic foraminiferal shell fluxes and assemblages in samples collected in a time-series sediment trap deployments in the Xisha Trough, South China Sea (SCS), from June 2009 to August 2011. The general flux shows a unimodal pattern, with high planktonic foraminiferal flux (900-1000 tests m-2 day-1) occurs during the period from late September/October to February, and low flux (200-300 tests m-2 day-1)during the rest period of the year. This flux pattern is contrast to the bimodal pattern of planktonic foraminiferal flux obtained from the central and southern SCS. Ten species, Globigeroides sacculifer, Globigerinoides ruber, Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerina calida, Globigerinella aequilateralis, Globigerina bulloides, Globigerinita glutinata, Orbulina univera and Globorotalia menardii, contributed about 96% of the total flux in each year. Among them, the monsoonal driven seasonality is most prominent for P. obliquiloculata, N. dutertrei and G. bulloides, with more than 70% of their species-specific total fluxes (93% for G. bulloides) occur from late September/October to February. This suggests G. bulloides can be used as a winter proxy-species. On the contrary, Globigeroides conglobatus, mostly appeared during June to August. G. sacculifer, G. ruber and G. aequilateralis generally follow the trend of the total flux of planktonic foraminifer, with about 50-60% of their total fluxes occur from late September/October to February. We also compared the size distribution of the dominant foraminiferal species in the > 250 micrometer fraction and 250-154 micrometer fraction, we found that most shells of G. aequilateralis, O. univera and G. menardii, and G. conglobatus mainly occur in the >250 micrometer fraction, and about 40% of G. sacculifer, 35% of P

  8. Distribution, sources and contamination assessment of heavy metals in surface sediments of the South Yellow Sea and northern part of the East China Sea.

    Science.gov (United States)

    Lu, Jian; Li, Anchun; Huang, Peng

    2017-11-15

    Surface sediment samples collected from the South Yellow Sea and northern part of the East China Sea during spring and autumn, respectively, were analyzed for grain size, aluminum, and heavy metals (Cr, Ni, Cu, Zn, and Pb) to evaluate heavy metal levels and the contamination status. The results showed that all of the heavy metal concentrations met the standard criteria of the Chinese National Standard Criteria for Marine Sediment Quality. Both the EFs and a multivariate analysis (PCA) indicated that Cr, Ni, Cu, and Zn were mainly from natural contributions, while Pb was influenced by anthropogenic inputs, especially during autumn. The geoaccumulation index of Pb near the mouth of the Yangtze River suggested that the pollution degree in autumn was heavier than that in spring, which might be caused by the greater river discharge in summer and more heavy metal adsorption with finer grain sizes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A new species and new record of deep-sea scale-worms (Polynoidae: Polychaeta) from the Okinawa Trough and the South China Sea.

    Science.gov (United States)

    Sui, Jixing; Li, Xinzheng

    2017-03-06

    A new species of scale-worm, Lepidonotopodium okinawae sp. nov. from the Okinawa Trough is described. The new species differs from the other species of Lepidonotopodium by having 24 segments and numerous foveolae on the surface of elytra with one globular micropapilla in every foveola. A new record of the mussel commensal Branchipolynoe pettiboneae Miura & Hashimoto, 1991 is reported and described from the northern South China Sea, where for the first time the scale-worm is noted as occurring at a cold-seep. Keys to distinguish the species of Branchipolynoe and Lepidonotopodium are provided.

  10. Observed 3D Structure, Generation, and Dissipation of Mesoscale Eddies in the South China Sea

    Science.gov (United States)

    Zhang, Z.; Tian, J.; Qiu, B.; Zhao, W.

    2016-12-01

    South China Sea (SCS), the largest marginal sea in the western Pacific, is abundant with strong mesoscale eddies as revealed by both satellite and in situ observations. The 3D structure, generation and dissipation mechanisms of the SCS mesoscale eddies, however, are still not well understood at present due to the lack of well-designed and comprehensive field observations. In order to address the above scientific issues, the SCS Mesoscale Eddy Experiment (S-MEE for short) was designed and conducted in the period from October 2013 to June 2014. As part of S-MEE, two bottom-anchored subsurface mooring arrays with one consisting of 10 moorings and the other 7 moorings, were deployed along the historical pathway of the mesoscale eddies in the northern SCS. All the moorings were equipped with ADCPs, RCMs, CTDs and temperature chains to make continues measurements of horizontal current velocity and temperature/salinity in the whole water column. In addition to moored observations, we also conducted two transects across the center of one anticyclonic eddy (AE) and made high-resolution hydrographic and turbulent mixing measurements. Based on the data collected by the S-MEE, we obtained the full-depth 3D structures of one AE and one cyclonic eddy (CE) and revealed their generation and dissipation mechanisms. For the first time we found that the eddies in the northern SCS extend from the surface to the sea bottom and display prominent tilted structures in the vertical. The AE was suggested to be shed from the Kuroshio current, which intruded into the SCS through Luzon Strait in winter. For the CE, its generation was associated with the barotropic instability of the Kuroshio current. By conducting an eddy energy budget analysis, we further identified that generation of submesoscale motions constitutes the dominant mechanism for the eddy dissipation. The findings in this study, not only provides new insights into the 3D structure of oceanic eddies, but also contributes to

  11. Double diffusion in the frontal zones of the Yellow and East China Seas in winter

    Science.gov (United States)

    Oh, K.; Lee, S.

    2017-12-01

    Where the cold, fresh water of the Yellow Sea (YS) and the warm, salty water of the East China Sea (ECS) meet, northern and southern fronts are formed in the southeastern YS and the northwestern ECS, respectively. Strong thermohaline fronts are formed on the northern front, and a strong thermocline and a temperature reversal phenomenon are represented in this front. To understand the water structure of this thermohaline zone, we examined double diffusion in the frontal zones in February 2003 using hydrographic data. In the northern front, the warm, salty Cheju Warm Current Water (CWCW) moved northwards along the bottom layer and the cold, fresh Yellow Sea Cold Water (YSCW) flowed southward in the upper layer. As a result, strong thermohaline fronts forms in the area where the two water masses met, and the slope was developed downward across the front. In this area, a strong thermocline and temperature reversal structures were present. The cold, fresh Korean Coastal Water (KCW) was also found in the upper layer near the thermocline, and has a low-temperature, low-salinity more than surrounding water. When cold, fresh water is located over warm, salty water, heat diffuses through the interface between the two water masses, and then the diffusive-convection can be expected to occur. On the other hand, when warm, salty water overlays cold, fresh water, heat in the upper layer is preferentially transferred downward, and the salt-fingering occurs. The diffusive-convection occurs predominantly in the northern thermohaline front, where the cold, fresh YSCW is situated above the warm, salty CWCW and has the effect of strengthening stratification, so that the water column maintains a physically stable structure. In addition, this phenomenon seems to play a role in maintaining the reversal structure. The salt-fingering occurs in upper layers of the northern front where the cold, fresh YSCW is located over the most cold, fresh KCW. Near the northern thermo-halocline zone, the

  12. Study on tsunami due to offshore earthquakes for Korea coast. Literature survey and numerical simulation on earthquake and tsunami in the Japan Sea and the East China Sea

    International Nuclear Information System (INIS)

    Matsuyama, Masafumi; Aoyagi, Yasuhira; Inoue, Daiei; Choi, Weon-Hack; Kang, Keum-Seok

    2008-01-01

    In Korea, there has been a concern on tsumami risks for the Nuclear Power Plants since the 1983 Nihonkai-Chubu earthquake tsunami. The maximum run-up height reached 4 m to north of the Ulchin nuclear power plant site. The east coast of Korea was also attacked by a few meters high tsunami generated by the 1993 Hokkaido Nansei-Oki earthquake. Both source areas of them were in the areas western off Hokkaido to the eastern margin of the Japan Sea, which remains another tsunami potential. Therefore it is necessary to study tsunami risks for coast of Korea by means of geological investigation and numerical simulation. Historical records of earthquake and tsunami in the Japan Sea were re-compiled to evaluate tsunami potential. A database of marine active faults in the Japan Sea was compiled to decide a regional potential of tsunami. Many developed reverse faults are found in the areas western off Hokkaido to the eastern margin of the Japan Sea. The authors have found no historical earthquake in the East China Sea which caused tunami observed at coast of Korea. Therefore five fault models were determined on the basis of the analysis results of historical records and recent research results of fault parameter and tunami. Tsunami heights were estimated by numerical simulation of nonlinear dispersion wave theory. The results of the simulations indicate that the tsunami heights in these cases are less than 0.25 m along the coast of Korea, and the tsunami risk by these assumed faults does not lead to severe impact. It is concluded that tsunami occurred in the areas western off Hokkaido to the eastern margin of the Japan Sea leads the most significant impact to Korea consequently. (author)

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

    Science.gov (United States)

    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  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 rising PAHs with their subsequent transport offshore and settling in the adjacent open sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

    Directory of Open Access Journals (Sweden)

    Robert J. Miller

    2015-07-01

    Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

  15. Precise Positioning of BDS, BDS/GPS: Implications for Tsunami Early Warning in South China Sea

    Directory of Open Access Journals (Sweden)

    Kejie Chen

    2015-11-01

    Full Text Available Global Positioning System (GPS has been proved to be a powerful tool for measuring co-seismic ground displacements with an application to seismic source inversion. Whereas most of the tsunamis are triggered by large earthquakes, GPS can contribute to the tsunami early warning system (TEWS by helping to obtain tsunami source parameters in near real-time. Toward the end of 2012, the second phase of the BeiDou Navigation Satellite System (BDS constellation was accomplished, and BDS has been providing regional positioning service since then. Numerical results indicate that precision of BDS nowadays is equivalent to that of the GPS. Compared with a single Global Satellite Navigation System (GNSS, combined BDS/GPS real-time processing can improve accuracy and especially reliability of retrieved co-seismic displacements. In the present study, we investigate the potential of BDS to serve for the early warning system of tsunamis in the South China Sea region. To facilitate early warnings of tsunamis and forecasting capabilities in this region, we propose to distribute an array of BDS-stations along the Luzon Island (Philippines. By simulating an earthquake with Mw = 8 at the Manila trench as an example, we demonstrate that such an array will be able to detect earthquake parameters in real time with a high degree of accuracy and, hence, contribute to the fast and reliable tsunami early warning system in this region.

  16. Bioremediation efficiency of the largest scale artificial Porphyra yezoensis cultivation in the open sea in China.

    Science.gov (United States)

    Wu, Hailong; Huo, Yuanzi; Zhang, Jianheng; Liu, Yuanyuan; Zhao, Yating; He, Peimin

    2015-06-15

    The bioremediation efficiency of China's largest scale Porphyra yezoensis cultivation for removing dissolved nutrients and controlling harmful algae was studied in the radial sandbanks waters of Jiangsu Province in the year 2012-2013. Mean nutrient concentration values in the P. yezoensis cultivation area were significantly lower than those in the non-cultivation area, especially during the cultivation season (p<0.05). Tissue nitrogen and phosphorus contents of seaweeds were 5.99-0.80% (dry weight (DW)) and 0.16-0.19% (DW), respectively. Production of P. yezoensis was 58950.87tons DW. Based on these values, 3688.15tons of tissue nitrogen and 105.61tons of tissue phosphorus were removed by harvesting P. yezoensis. The richness index of the red tide species Skeleton emacostatum declined from 0.32 to 0.05 during the P. yezoensis cultivation season. These results indicate that large-scale cultivation of P. yezoensis can be used to efficiently alleviate eutrophication and control harmful algae blooms in open sea. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Millennial mercury records derived from ornithogenic sediment on Dongdao Island, South China Sea.

    Science.gov (United States)

    Yan, Hong; Wang, Yuhong; Cheng, Wenhan; Sun, Liguang

    2011-01-01

    Two ornithogenic sediment cores, which have a time span of 1000 years and are influenced by red-footed booby (Sula sula), were collected from Dongdao Islands, South China Sea. The determined mercury concentrations of the two cores show similar and substantial fluctuations during the past millennium, and the fluctuations are most likely caused by the changes in mercury level of the ocean environment and in anthropogenic Hg emission. For the past 500 years, the mercury concentration in the red-footed booby excrement has a striking association with global anthropogenic mercury emission. The mercury concentration increased rapidly after AD 1600 in corresponding to beginning of the unparalleled gold and silver mining in South Central America that left a large volume of anthropogenic mercury pollution. Since the Industrial Revolution, the mercury level has increased at a fast pace, very likely caused by modern coal combustion, chlor-alkali and oil refining industries. The comparison of mercury profiles from different places on earth suggested that anthropogenic mercury pollution after the Industrial Revolution is more severe in Northern Hemisphere than in Antarctica.

  18. Wave characteristics and hydrodynamics at a reef island on Dongsha Atoll in the South China Sea

    Science.gov (United States)

    Su, Shih-Feng; Chiang, Te-Yun; Lin, Yi-Hao; Chen, Jia-Lin

    2017-04-01

    An inhabited coral reef island, located at the Dongsha Atoll in the northern South China Sea, is frequently attacked by typhoon waves. Coastline has suffered severe erosion and coastal inundation during certain typhoon paths. Groins were therefore built surround the island to stabilize the shoreline. However, the engineering structures redistributed the characteristics of hydrodynamics, which resulted in the disappearance of seasonal sediment movements on the reef flat. Additionally, infragravity waves (20-200 sec) on reefs have be found to generate strong resonance during energetic wave events. To understand wave characteristics and nearshore circulations around the reef under typical waves and typhoon waves, a phase-averaged and a phase-resolving wave models validated with previous field experiments are used to simulate significant wave height, wave setup and reef circulations. The phase-resolving model is specially applied to investigate infragravity motions around the island. Model results will illustrate the spatial variations of infragravity-wave field and wave-induced nearshore circulation and can provide information for coastal management and protection.

  19. An extreme internal solitary wave event observed in the northern South China Sea.

    Science.gov (United States)

    Huang, Xiaodong; Chen, Zhaohui; Zhao, Wei; Zhang, Zhiwei; Zhou, Chun; Yang, Qingxuan; Tian, Jiwei

    2016-07-21

    With characteristics of large amplitude and strong current, internal solitary wave (ISW) is a major hazard to marine engineering and submarine navigation; it also has significant impacts on marine ecosystems and fishery activity. Among the world oceans, ISWs are particular active in the northern South China Sea (SCS). In this spirit, the SCS Internal Wave Experiment has been conducted since March 2010 using subsurface mooring array. Here, we report an extreme ISW captured on 4 December 2013 with a maximum amplitude of 240 m and a peak westward current velocity of 2.55 m/s. To the authors' best knowledge, this is the strongest ISW of the world oceans on record. Full-depth measurements also revealed notable impacts of the extreme ISW on deep-ocean currents and thermal structures. Concurrent mooring measurements near Batan Island showed that the powerful semidiurnal internal tide generation in the Luzon Strait was likely responsible for the occurrence of the extreme ISW event. Based on the HYCOM data-assimilation product, we speculate that the strong stratification around Batan Island related to the strengthening Kuroshio may have contributed to the formation of the extreme ISW.

  20. Marine Group II Dominates Planktonic Archaea in Water Column of the Northeastern South China Sea

    Directory of Open Access Journals (Sweden)

    Haodong Liu

    2017-06-01

    Full Text Available Temperature, nutrients, and salinity are among the important factors constraining the distribution and abundance of microorganisms in the ocean. Marine Group II (MGII belonging to Euryarchaeota commonly dominates the planktonic archaeal community in shallow water and Marine Group I (MGI, now is called Thaumarchaeota in deeper water in global oceans. Results of quantitative PCR (qPCR and 454 sequencing in our study, however, showed the dominance of MGII in planktonic archaea throughout the water column of the northeastern South China Sea (SCS that is characterized by strong water mixing. The abundance of ammonia-oxidizing archaea (AOA representing the main group of Thaumarchaeota in deeper water in the northeastern SCS was significantly lower than in other oceanic regions. Phylogenetic analysis showed that the top operational taxonomic units (OTUs of the MGII occurring predominantly below 200 m depth may be unique in the northeastern SCS based on the observation that they are distantly related to known sequences (identity ranging from 90–94%. The abundance of MGII was also significantly correlated with total bacteria in the whole column, which may indicate that MGII and bacteria may have similar physiological or biochemical properties or responses to environmental variation. This study provides valuable information about the dominance of MGII over AOA in both shallow and deep water in the northeastern SCS and highlights the need for comprehensive studies integrating physical, chemical, and microbial oceanography.

  1. Observations of the turbulent kinetic energy dissipation rate in the upper central South China Sea

    Science.gov (United States)

    Liang, Chang-Rong; Chen, Gui-Ying; Shang, Xiao-Dong

    2017-05-01

    Measurements of the turbulent kinetic energy dissipation rate ( ɛ), velocity, temperature, and salinity were obtained for the upper ocean of the central South China Sea (14.5° N, 117.0° E) during an experimental campaign from May 11 to 13, 2010. Dissipation in the diurnal mixed layer showed a diurnal variability that was strongly affected by the surface buoyancy flux. Dissipation was enhanced ( ɛ ˜ 10-7 W kg-1) at night due to the convective mixing and was weakened ( ɛ ˜ 10-9 W kg-1) in daytime due to the stratification. Dissipation in the thermocline varied with time under the influence of internal waves. Shear from high-frequency internal waves (period ˜8 h) played an important role in enhancing the turbulent mixing in the thermocline. In the period of strong high-frequency internal waves, the shear from high-frequency internal waves became strong and the depth-averaged ɛ in the thermocline was elevated by almost one order of magnitude. Compared with the dissipation in the thermocline, dissipation below was weaker (the time-averaged ɛ ˜ 10-10 W kg-1). The observation indicates that the dissipation rates during the measurements can be parameterized by the MacKinnon-Gregg model that is widely used in the continental shelf but are not in agreement with the Gregg-Henyey model used for the open ocean.

  2. Observations of turbulent energy dissipation rate in the upper ocean of the central South China Sea

    Science.gov (United States)

    Chen, G.

    2016-02-01

    Measurements of turbulent energy dissipation rate, velocity, temperature, and salinity were obtained in the upper ocean of the central South China Sea (14.5˚N, 117.0˚E) during an experimental campaign from May 11th to 13th 2010. Dissipation rate was elevated ( 10-7 Wkg-1) at night by convection mixing and was weakened ( 10-9 Wkg-1) in daytime due to the warming stratification. Thermocline dissipation rate varied with time ( 10-9 Wkg-1 to 10-8 Wkg-1) under the influence of internal waves. Energy was transferred from the diurnal internal tides to high frequency internal waves through nonlinear wave-wave interactions. This energy cascade process was accompanied by elevated shear and enhanced dissipation, which played an important role in the turbulent mixing in thermocline. Compare with the thermocline dissipation, dissipation below the thermocline was more stable and weak ( 10-10 Wkg-1). The observed dissipation rate during the measurement was well parameterized by the MacKinnon-Gregg parameterization (a model based on a reinterpretation of wave-wave interaction theory), whereas the Gregg-Henyey parameterization was not in good agreement with the observed dissipation rate.

  3. Mercury pollution in fish from South China Sea: levels, species-specific accumulation, and possible sources.

    Science.gov (United States)

    Liu, Jinling; Xu, Xiangrong; Yu, Shen; Cheng, Hefa; Hong, Yiguo; Feng, Xinbin

    2014-05-01

    Both total mercury (THg) and methylmercury (MeHg) levels in fish collected from South China Sea (SCS) were studied to understand Hg pollution in Chinese tropical marine ecosystems. The average THg concentrations in fish species ranged from 39.6 μg/kg for rabbitfish (Siganus fuscessens) to 417 μg/kg for thornfish (Terapon jarbua), while those of MeHg varied from 13 μg/kg (rabbitfish) to 176 μg/kg (thornfish). The median values of MeHg/THg ratios in different fish species ranged from 36 to 85%. Significant inter-species differences of THg and MeHg in fish were observed due to feeding habits and fish sizes. Overall, carnivorous fish had higher levels of THg, MeHg and MeHg/THg ratios than omnivorous and herbivorous fish. High Hg levels in fish of the SCS were probably related to Hg input from atmospheric deposition and anthropogenic activities. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Probabilistic ecological risk assessment of polycyclic aromatic hydrocarbons in southwestern catchments of the Bohai Sea, China.

    Science.gov (United States)

    Zeng, Lin; Zeng, Siyu; Dong, Xin; Zhang, Tianzhu; Chen, Jining

    2013-10-01

    A probability risk assessment was undertaken to study the individual and combined ecological risks induced by six polycyclic aromatic hydrocarbons (PAHs) both in surface water and sediment from southwestern catchments of the Bohai Sea, China. The actual measured PAH concentrations in water and sediment were compared with toxicity effect data (the 10th percentile of predicted no effect concentration) to calculate the risk quotients (RQs) for an individual PAH. The equilibrium partitioning method was applied to estimate toxicity data in sediment. A method based on the equivalent concentration concept was proposed and applied to assess the combined ecological risk of multiple PAHs. Monte Carlo simulation and bootstrap technique were utilized to calculate the distribution of RQs and associated uncertainties. The ecological safety level was defined by RQ ≤ 1. Results indicated that both in water and sediment, fluoranthene and pyrene posed the highest risks, whereas acenaphthene and fluorene posed negligible risks. Naphthalene and phenanthrene did not pose risks to the ecological community in surface water but had relatively higher risks in sediment. The median RQs of combined risk in surface water and sediment were 0.934 and 2.42, and the probabilities of RQ > 1 were up to 0.473 and 0.599, respectively, which were much higher than the individual compound acting alone. The risk level in sediment was quite higher than in surface water probably owing to the non-equilibrium distribution between two phases, which suggested that local authorities should focus more on sediment quality management.

  5. Dinophysis caudata generated lipophilic shellfish toxins in bivalves from the Nanji Islands, East China Sea

    Science.gov (United States)

    Jiang, Tao; Xu, Yixiao; Li, Yang; Qi, Yuzao; Jiang, Tianjiu; Wu, Feng; Zhang, Fan

    2014-01-01

    A 12-month program of monitoring potentially toxic microalgae (that produce lipophilic shellfish toxins; LSTs) and their toxins in bivalves was conducted from April 2006 to March 2007 in the Nanji Islands, East China Sea. Two Dinophysis species, D. caudata and D. acuminata, were identified, and D. caudata was found to be the dominant species. D. caudata was detected in water samples between April and June 2006, and between February and March 2007. It reached its highest abundances in May, with a mean abundance of 1.38×102 cells/L in surface water and 1.25×102 cells/L in bottom water (cultured bivalves sampled between April and June were contaminated with LSTs, with an average toxicity of 85 μg okadaic acid (OA) eq./100 g meat, which was four times higher than the Chinese regulatory limit (20 μg OA eq./100 g meat). Ten out of fifteen wild samples (66.7%) collected during the same period were positive for LSTs, and contained an average LST toxicity of 45 μg OA eq./100 g meat (more than twice the regulatory value). Cultured Patinopecten yessoensis collected on 15 May 2006 had the highest toxicity, 320 μg OA eq./100 g meat, and relatively high toxicities (80 to 160 μg OA eq./100 g meat) were found in bivalves until the end of July.

  6. Organophosphate esters in sediment cores from coastal Laizhou Bay of the Bohai Sea, China.

    Science.gov (United States)

    Wang, Yan; Wu, Xiaowei; Zhang, Qiaonan; Hou, Minmin; Zhao, Hongxia; Xie, Qing; Du, Juan; Chen, Jingwen

    2017-12-31

    Concentrations and vertical distributions of organophosphate esters (OPEs) were investigated in the sediment cores collected from the Laizhou Bay, Bohai Sea of China. The total concentrations of OPEs in the sediment core (CA) collected near the Yellow River Estuary were in the range of 11.8-102ng/g, while the total concentrations in the sediment core (CB) near a mariculture area were 6.65-41.5ng/g. Significantly high concentrations of OPEs were found in the sediments near the Yellow River Estuary than those in the mariculture area. Vertical distributions in the sediment cores demonstrated a recent increase of OPE emissions, especially for tri-n-butyl phosphate (TnBP), tris (2-chloroethyl) phosphate (TCEP), and tris (2-chloroisopropyl) phosphate (TCPP). Generally, TCEP and TCPP were the dominant congeners in the sediment cores, while the profiles of TnBP were increase in the surface 0-20cm layers of the CA core. OPEs in the CA core may be remarkably influenced by the discharge of Yellow River, whereas OPEs in the CB core may originate from the transport through seawater. The remarkable increase of OPE flame retardants in the surface sediments raises the concern about their emissions and risks to the environment and indicates the need for further monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Ingestion of microplastics by natural zooplankton groups in the northern South China Sea.

    Science.gov (United States)

    Sun, Xiaoxia; Li, Qingjie; Zhu, Mingliang; Liang, Junhua; Zheng, Shan; Zhao, Yongfang

    2017-02-15

    The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505μm and 160μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125μm and 167μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1pieces/m 3 for Net I and 131.5pieces/m 3 for Net II. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Effect of potential vorticity flux on the circulation in the South China Sea

    Science.gov (United States)

    Zhu, Yaohua; Sun, Junchuan; Wang, Yonggang; Wei, Zexun; Yang, Dezhou; Qu, Tangdong

    2017-08-01

    This study analyzes temperature and salinity products from the U.S. Navy Generalized Digital Environment Model. To avoid the fictitious assumption of no-motion reference level, a P-vector inverse method is employed to derive geostrophic velocity. Line integral of geostrophic velocity shows evidence for the existence of a sandwiched circulation in the South China Sea (SCS), i.e., cyclonic circulation in the subsurface and deep layers and anticyclonic in the intermediate layer. To reveal the factors responsible for the sandwiched circulation, we derive the potential vorticity equation based on a four-and-a-half-layer quasi-geostrophic model and apply theoretical potential vorticity constraint to density layers. The result shows that the sandwiched circulation is largely induced by planetary potential vorticity flux through lateral boundaries, mainly the Luzon Strait. This dynamical mechanism lies in the fact that the net potential vorticity inflow in the subsurface and deep layers leads to a positive layer-average vorticity in the SCS basin, yielding vortex stretching and a cyclonic basin-wide circulation. On the contrary, the net potential vorticity outflow in the intermediate layer induces a negative layer-average vorticity, generating an anticyclonic basin-wide circulation in the SCS. Furthermore, by illustrating different consequence from depth/density layers, we clarify that density layers are essential for applying theoretical potential vorticity constraint to the isolated deep SCS basin.

  9. Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea.

    Science.gov (United States)

    Hung, Chin-Chang; Ko, Fung-Chi; Gong, Gwo-Ching; Chen, Kuo-Shu; Wu, Jian-Ming; Chiang, Hsin-Lun; Peng, Sen-Chueh; Santschi, Peter H

    2014-06-15

    The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500 ng m(-3) in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2-23 ng m(-3)) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Pezizomycotina dominates the fungal communities of South China Sea sponges Theonella swinhoei and Xestospongia testudinaria.

    Science.gov (United States)

    Jin, Liling; Liu, Fang; Sun, Wei; Zhang, Fengli; Karuppiah, Valliappan; Li, Zhiyong

    2014-12-01

    Compared with the knowledge of sponge-associated bacterial diversity and ecological roles, the fungal diversity and ecological roles of sponges remain largely unknown. In this study, the fungal diversity and protein synthesis potential in two South China Sea sponges Theonella swinhoei and Xestospongia testudinaria were investigated by rRNA vs. rRNA gene analysis. EF4/fung5 was chosen after a series of PCR tests to target fungal 18S rRNA and 18S rRNA gene. Altogether, 283 high-quality sequences were obtained, which resulted in 26 Operational taxonomic units (OTUs) that were assigned to Ascomycota, Basidiomycota, and Blastocladiomycota. At subphylum level, 77.3% of sponge-derived sequences were affiliated with Pezizomycotina. The fungal compositions of T. swinhoei and X. testudinaria were different from that of ambient seawater. The predominant OTU shared between two sponges was rare in seawater, whereas the most abundant OTUs in seawater were not found in sponges. Additionally, the major OTUs of sponge cDNA datasets were shared in two sponges. The fungal diversity illustrated by sponge cDNA datasets correlated well with that derived from sponge DNA datasets, indicating that the major members of sponge-associated fungi had protein synthesis potential. This study highlighted the diversity of Pezizomycotina in marine sponge-fungi symbioses and the necessity of investigating ecological roles of sponge-associated fungi. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  11. [Study on secondary metabolites of marine fungus Penicillium sp. FS60 from the South China Sea].

    Science.gov (United States)

    Zhang, Ling; Li, Dong-Li; Chen, Yu-Chan; Tao, Mei-Hua; Zhang, Wei-Min

    2012-07-01

    To study the secondary metabolites of the marine fungus Penicillium sp. FS60 from the South China Sea and their cytotoxicities. The compounds were isolated from the culture of strain FS60 by various chromatographic methods (silica gel, reverse silica gel, Sephadex-LH20, preparative TLC, HPLC and PTLC) and recrystallization. Their structures were identified by extensive analysis of their spectroscopic data. Compounds were tested for their cytotoxicities against SF-268, MCF-7, and NCI-H460 cell lines by SRB method. While, Compounds were tested for their antibacterial activities against S. aureus, E. coli and P. aeruginosa. Seven compounds were isolated from the culture and identified as methyl 2,4-dihydroxy-3,5,6-trimethylbenzoate (1), 4-hydroxyacetophenone (2), 5-hydroxymethyl-furoic acid (3), isochromophilones VIII (4), ergosterol (5), ergosterol peroxide (6), and cerevisterol (7). Compound 1 is isolated from the genus Penicillium for the first time. Compound 3 is demonstrated to have significant inhibition against S. aureus and P. aeruginosa. Compound 4 is demonstrated to have significant inhibition against the three cell lines.

  12. On the Wind Energy Resource and Its Trend in the East China Sea

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    Adekunle Ayodotun Osinowo

    2017-01-01

    Full Text Available This study utilizes a 30-year (1980–2009 10 m wind field dataset obtained from the European Center for Medium Range Weather Forecast to investigate the wind energy potential in the East China Sea (ECS by using Weibull shape and scale parameters. The region generally showed good wind characteristics. The calculated annual mean of the wind power resource revealed the potential of the region for large-scale grid-connected wind turbine applications. Furthermore, the spatiotemporal variations showed strong trends in wind power in regions surrounding Taiwan Island. These regions were evaluated with high wind potential and were rated as excellent locations for installation of large wind turbines for electrical energy generation. Nonsignificant and negative trends dominated the ECS and the rest of the regions; therefore, these locations were found to be suitable for small wind applications. The wind power density exhibited an insignificant trend in the ECS throughout the study period. The trend was strongest during spring and weakest during autumn.

  13. Purification and characterization of an alkaline protease from Micrococcus sp. isolated from the South China Sea

    Science.gov (United States)

    Hou, Enling; Xia, Tao; Zhang, Zhaohui; Mao, Xiangzhao

    2017-04-01

    Protease is wildly used in various fields, such as food, medicine, washing, leather, cosmetics and other industrial fields. In this study, an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China Sea was purified and characterized. The growth curve and enzyme activity curve indicated that the cell reached a maximum concentration at the 30th hour and the enzyme activity reached the maximum value at the 36th hour. The protease was purified with 3 steps involving ammonium sulfate precipitation, ion-exchange chromatography and hydrophobic chromatography with 8.22-fold increase in specific activity and 23.68% increase in the recovery. The molecular mass of the protease was estimated to be 25 kDa by SDS-PAGE analysis. The optimum temperature and pH for the protease activity were 50°C and pH 10.0, respectively. The protease showed a strong stability in a wide range of pH values ranging from 6.0-11.0, and maintained 90% enzyme activity in strong alkaline environment with pH 11.0. Inhibitor trials indicated that the protease might be serine protease. But it also possessed the characteristic of metalloprotease as it could be strongly inhibited by EDTA and strongly stimulated by Mn2+. Evaluation of matrix-assisted laser desorption ionization/time-of-flight MS (MALDI-TOF-TOF/MS) showed that the protease might belong to the peptidase S8 family.

  14. Relation of submarine landslide to hydrate occurrences in Baiyun Depression, South China Sea

    Science.gov (United States)

    Sun, Yunbao; Zhang, Xiaohua; Wu, Shiguo; Wang, Lei; Yang, Shengxiong

    2018-02-01

    Submarine landslides have been observed in the Baiyun Depression of the South China Sea. The occurrence of hydrates below these landslides indicates that these slope instabilities may be closely related to the massive release of methane. In this study, we used a simple Monte-Carlo model to determine the first-order deformation pattern of a gravitationally destabilizing slope. The results show that a stress concentration occurs due to hydrate dissociation on the nearby glide surface and on top of a gas chimney structure. Upon the dissolution of the gas hydrate, slope failure occurs due to the excess pore pressure generated by the dissociation of the gas hydrates. When gas hydrates dissociate at shallow depths, the excess pore pressure generated can be greater than the total stress acting at those points, along with the forces that resist sliding. Initially, the failure occurs at the toe of the slope, then extends to the interior. Although our investigation focused only on the contribution of hydrate decomposition to submarine landslide, this process is also affected by both the slope material properties and topography.

  15. Imidazole Alkaloids from the South China Sea Sponge Pericharax heteroraphis and Their Cytotoxic and Antiviral Activities

    Directory of Open Access Journals (Sweden)

    Kai-Kai Gong

    2016-01-01

    Full Text Available Marine sponges continue to serve as a rich source of alkaloids possessing interesting biological activities and often exhibiting unique structural frameworks. In the current study, chemical investigation on the marine sponge Pericharax heteroraphis collected from the South China Sea yielded one new imidazole alkaloid named naamidine J (1 along with four known ones (2–5. Their structures were established by extensive spectroscopic methods and comparison of their data with those of the related known compounds. All the isolates possessed a central 2-aminoimidazole ring, substituted by one or two functionalized benzyl groups in some combination of the C4 and C5 positions. The cytotoxicities against selected HL-60, HeLa, A549 and K562 tumor cell lines and anti-H1N1 (Influenza a virus (IAV activity for the isolates were evaluated. Compounds 1 and 2 exhibited cytotoxicities against the K562 cell line with IC50 values of 11.3 and 9.4 μM, respectively. Compound 5 exhibited weak anti-H1N1 (influenza a virus, IAV activity with an inhibition ratio of 33%.

  16. A 700-year record of mercury in avian eggshells of Guangjin Island, South China Sea

    International Nuclear Information System (INIS)

    Xu Liqiang; Liu Xiaodong; Sun Liguang; Chen Qianqian; Yan Hong; Liu Yi; Luo Yuhan; Huang Jing

    2011-01-01

    Ancient eggshells over the past 700 years were extracted from an ornithogenic sediment profile on Guangjin Island, South China Sea. Based on SEM and nitrogen isotope analyses, we determined that neither post-depositional processes nor seabirds' dietary changes had a large influence on eggshell Hg levels. The historical change of Hg in these eggshells was reconstructed. Eggshell Hg was a marker for past Hg deposition in marine environment. The eggshell Hg showed three small peaks at around 1300AD, 1600 AD and 1700-1750AD and rapid increase since 1800 AD. Before 1970 AD the Hg deposition in the Xisha area had global distribution characteristics, with increased Hg emissions due to global anthropogenic activities in industrial times. However, after 1970 AD, a further sharp increase up to present day occurred, implying that the Hg production center had gradually shifted from Europe and America to Asia. - Research highlights: → Eggshell Hg is a marker for past mercury deposition in marine environment. → This is a Hg record from ancient sequential eggshell samples. → The 700-year record of eggshell Hg is closely related to human activities. → Eggshell Hg suggests the increase of Hg production in Asia over the past decades. - Our work provides a potential use of ancient sequential eggshells to reconstruct past mercury deposition in marine ecosystems.

  17. Diversity and bioprospecting of culturable actinomycetes from marine sediment of the Yellow Sea, China.

    Science.gov (United States)

    Xiong, Zhi-Qiang; Liu, Qiao-Xia; Pan, Zhao-Long; Zhao, Na; Feng, Zhi-Xiang; Wang, Yong

    2015-03-01

    Marine actinomycetes are a potential source of a wide variety of bioactive natural products. In this work, seven pretreatments, three selective isolation media, and five artificial seawater concentrations were used to isolate actinomycetes from the sediments collected from Yellow Sea, China. Statistical analysis showed that only the isolation medium strongly affected the total and bioactive numbers of actinomycete isolates. A total of 613 actinobacterial strains were isolated and screened for antimicrobial activities; 154 isolates showed activity against at least one of nine test drug-resistant microorganisms. Eighty-nine representatives with strong antimicrobial activity were identified phylogenetically based on 16S rRNA gene sequencing, which were assigned to five different actinomycete genera Streptomyces, Kocuria, Saccharomonospora, Micromonospora, and Nocardiopsis. Using PCR-based screening for six biosynthetic genes of secondary metabolites, all 45 isolates with acute activity have at least one biosynthetic gene, 28.8 % of which possess more than three biosynthetic genes. As a case, strain SMA-1 was selected for antimicrobial natural product discovery. Three diketopiperazine dimers including a new compound iso-naseseazine B (1) and two known compounds naseseazine B (2) and aspergilazine A (3) were isolated by bioassay-guided separation. These results suggested that actinomycetes from marine sediments are a potential resource of novel secondary metabolites and drugs.

  18. A clustering analysis of eddies' spatial distribution in the South China Sea

    Science.gov (United States)

    Yi, J.; Du, Y.; Wang, X.; He, Z.; Zhou, C.

    2013-02-01

    Spatial variation is important for studying the mesoscale eddies in the South China Sea (SCS). To investigate such spatial variations, this study made a clustering analysis on eddies' distribution using the K-means approach. Results showed that clustering tendency of anticyclonic eddies (AEs) and cyclonic eddies (CEs) were weak but not random, and the number of clusters were proved greater than four. Finer clustering results showed 10 regions where AEs densely populated and 6 regions for CEs in the SCS. Previous studies confirmed these partitions and possible generation mechanisms were related. Comparisons between AEs and CEs revealed that patterns of AE are relatively more aggregated than those of CE, and specific distinctions were summarized: (1) to the southwest of Luzon Island, AEs and CEs are generated spatially apart; AEs are likely located north of 14° N and closer to shore, while CEs are to the south and further offshore. (2) The central SCS and Nansha Trough are mostly dominated by AEs. (3) Along 112° E, clusters of AEs and CEs are located sequentially apart, and the pairs off Vietnam represent the dipole structures. (4) To the southwest of the Dongsha Islands, AEs are concentrated to the east of CEs. Overlaps of AEs and CEs in the northeastern and southern SCS were further examined considering seasonal variations. The northeastern overlap represented near-concentric distributions while the southern one was a mixed effect of seasonal variations, complex circulations and topography influences.

  19. Genetic diversity of bacterial communities and gene transfer agents in northern South China Sea.

    Directory of Open Access Journals (Sweden)

    Fu-Lin Sun

    Full Text Available Pyrosequencing of the 16S ribosomal RNA gene (rDNA amplicons was performed to investigate the unique distribution of bacterial communities in northern South China Sea (nSCS and evaluate community structure and spatial differences of bacterial diversity. Cyanobacteria, Proteobacteria, Actinobacteria, and Bacteroidetes constitute the majority of bacteria. The taxonomic description of bacterial communities revealed that more Chroococcales, SAR11 clade, Acidimicrobiales, Rhodobacterales, and Flavobacteriales are present in the nSCS waters than other bacterial groups. Rhodobacterales were less abundant in tropical water (nSCS than in temperate and cold waters. Furthermore, the diversity of Rhodobacterales based on the gene transfer agent (GTA major capsid gene (g5 was investigated. Four g5 gene clone libraries were constructed from samples representing different regions and yielded diverse sequences. Fourteen g5 clusters could be identified among 197 nSCS clones. These clusters were also related to known g5 sequences derived from genome-sequenced Rhodobacterales. The composition of g5 sequences in surface water varied with the g5 sequences in the sampling sites; this result indicated that the Rhodobacterales population could be highly diverse in nSCS. Phylogenetic tree analysis result indicated distinguishable diversity patterns among tropical (nSCS, temperate, and cold waters, thereby supporting the niche adaptation of specific Rhodobacterales members in unique environments.

  20. Studies on the secondary metabolites from the Indian gorgonian Subergorgia suberosa: Isolation and characterization of four analogues of the cardiotoxin subergorgic acid

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Naik, C.G.; Kamat, S.Y.; Puar, M.S.; Das, Pradip; Hegde, V.R.

    Chemical investigation of the methanol extract of the Indian Ocean gorgonian coral Subergorgia suberosa resulted in isolation and identification of four novel compounds 2-5. Structural investigation revealed compound 1 to be subergorgic acid...

  1. Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas.

    Science.gov (United States)

    He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

    2014-09-16

    Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70-140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas.

  2. Demographic response of cutlassfish (Trichiurus japonicus and T. nanhaiensis) to fluctuating palaeo-climate and regional oceanographic conditions in the China seas

    Science.gov (United States)

    He, Lijun; Zhang, Aibing; Weese, David; Li, Shengfa; Li, Jiansheng; Zhang, Jing

    2014-01-01

    Glacial cycles of the Quaternary have heavily influenced the demographic history of various species. To test the evolutionary impact of palaeo-geologic and climatic events on the demographic history of marine taxa from the coastal Western Pacific, we investigated the population structure and demographic history of two economically important fish (Trichiurus japonicus and T. nanhaiensis) that inhabit the continental shelves of the East China and northern South China Seas using the mitochondrial cytochrome b sequences and Bayesian Skyline Plot analyses. A molecular rate of 2.03% per million years, calibrated to the earliest flooding of the East China Sea shelf (70–140 kya), revealed a strong correlation between population sizes and primary production. Furthermore, comparison of the demographic history of T. japonicus populations from the East China and South China Seas provided evidence of the postglacial development of the Changjiang (Yangtze River) Delta. In the South China Sea, interspecific comparisons between T. japonicus and T. nanhaiensis indicated possible evolutionary responses to changes in palaeo-productivity that were influenced by East Asian winter monsoons. This study not only provides insight into the demographic history of cutlassfish but also reveals potential clues regarding the historic productivity and regional oceanographic conditions of the Western Pacific marginal seas. PMID:25223336

  3. Polybrominated diphenyl ethers (PBDEs) in sediments of the coastal East China Sea: Occurrence, distribution and mass inventory

    International Nuclear Information System (INIS)

    Li Yuanyuan; Lin Tian; Chen Yingjun; Hu Limin; Guo Zhigang; Zhang Gan

    2012-01-01

    Polybrominated diphenyl ethers (PBDEs) of sixty-three sediment samples from the coastal East China Sea (ECS), extending ∼1000 km from the Yangtze River Estuary to the south, were measured. The levels of BDE-209 and ∑PBDE 7 (sum of BDE-28, 47, 99, 100, 153, 154, 183) were 0.3–44.6 ng/g (dry weight) and nd-8.0 ng/g, respectively. BDE-209 was the predominant congener, followed by BDE-99/100. This was consistent with the historical and current usage of PBDE mixtures in China. The compositions and distribution of PBDEs suggest that the PBDEs in this area could be mainly from the coastal electronic waste dismantling/recycling and Yangtze River input. The poor correlations between TOC, grain size of sediments with PBDEs imply that the PBDE distribution is more related to their land-based inputs rather than the sediment characters in the area. The coastal ECS is an important sink of PBDEs (7.5 t/yr) in the world. - Highlights: ► First report on the levels, distribution and inventory of PBDEs in the inner shelf of the ECS. ► PBDEs were mainly from the coastal electronic waste dismantling/recycling and Yangtze River. ► PBDE distribution was related to the land-based inputs rather than the sediment characters. ► The coastal East China Sea is an important sink of the PBDEs in the world. - The levels, distribution, potential sources and mass inventory of PBDEs in sediments of the coastal East China Sea were revealed.

  4. Significant breakthrough in proprietary deepwater natural gas exploration in the northern South China Sea and its inspiration

    Directory of Open Access Journals (Sweden)

    Yuhong Xie

    2014-12-01

    Full Text Available In 2014, Zhanjiang Branch of CNOOC Limited obtained high oil and gas flows (160 × 104 m3/d in Well LS 17-2-1 in northern South China Sea. The tested formation is the Neogene Upper Miocene Huangliu Fm. This is the first self-explored natural gas field in deep water area in China. Exploration in this area underwent three periods: (1 Reconnaissance exploration period (before 2002: Limited by techniques, the major exploration was in shallow water areas; (2 Foreign cooperative exploration period (2002–2012: As the discovered reserve scale was small, and there is no economic benefit, the partners successively gave up their exploration equities in the deep water area of western South China Sea; however, the high quality source rocks and reservoirs were confirmed in the deep water area of the South China Sea, revealing the mask of hydrocarbon exploration in this region; (3 Self-exploration period (since 2013: Relying on national science and technology major projects and its scientific research and production, Zhanjiang Company of CNOOC conducted several scientific researches on seismic data acquisition and processing, high-quality reservoir distribution, key factors for hydrocarbon accumulation in deep water areas, optimized and confirmed Lingshui 17-2 structure as the first drilling target, and obtained significant exploration breakthrough. Lingshui 17-2 structure is located in the Ledong-Lingshui section of the Central Canyon. Its major target layer is the Huangliu Fm. Its total thickness is over 150 m, with sandstone ratio of 75.4%, maximum single layer thickness of 52 m, porosity ranging 30.0%–33.7% (31.5% averagely, permeability ranging 293–2512 mD (633 mD averagely, belonging to reservoir with ultrahigh porosity and high-ultrahigh permeability. The exploration breakthrough in Lingshui 17-2 shows the giant potentiality of hydrocarbon exploration in this deep water area.

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

    Science.gov (United States)

    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.

  6. Eupalmerin acetate, a novel anticancer agent from Caribbean gorgonian octocorals, induces apoptosis in malignant glioma cells via the c-Jun NH2-terminal kinase pathway.

    Science.gov (United States)

    Iwamaru, Arifumi; Iwado, Eiji; Kondo, Seiji; Newman, Robert A; Vera, Burnilda; Rodríguez, Abimael D; Kondo, Yasuko

    2007-01-01

    The marine ecosystem is a vast but largely untapped resource for potential naturally based medicines. We tested 15 compounds derived from organisms found in the Caribbean Sea (14 gorgonian octocoral-derived compounds and one sponge-derived compound) for their anticancer effects on human malignant glioma U87-MG and U373-MG cells. Eupalmerin acetate (EPA) was chosen as the lead compound based on its longer-term stability and greater cytotoxicity than those of the other compounds we tested in these cell types. EPA induced G(2)-M cell cycle arrest and apoptosis via the mitochondrial pathway; it translocated Bax from the cytoplasm to the mitochondria and dissipated the mitochondrial transmembrane potential in both cell types. EPA was found to increase phosphorylated c-Jun NH(2)-terminal kinase (JNK) by >50% in both U87-MG and U373-MG cells. A specific JNK inhibitor, SP600125, inhibited EPA-induced apoptosis, confirming the involvement of the JNK pathway in EPA-induced apoptotic cell death. Furthermore, 7 days of daily intratumoral injections of EPA significantly suppressed the growth of s.c. malignant glioma xenografts (P < 0.01, on day 19). These results indicate that EPA is therapeutically effective against malignant glioma cells in vitro and in vivo and that it, or a similar marine-based compound, may hold promise as a clinical anticancer agent.

  7. China’s Potential for Economic Coercion in the South China Sea Disputes: A Comparative Study of the Philippines and Vietnam

    Directory of Open Access Journals (Sweden)

    Madhu Sudan Ravindran

    2012-01-01

    Full Text Available With tensions rising in the South China Sea, China’s use of its economic leverage over Southeast Asian countries has recently come into focus. With increasing economic and trade ties between China and Southeast Asia, the question being asked is whether China can successfully impose economic sanctions to gain policy concessions in the South China Sea disputes. This paper examines China’s relations with the Philippines and Vietnam and analyses the possibility of a successful economic sanction by China against these two countries in future disputes. The article concludes that Vietnam may be more vulnerable economically to Chinese sanctions than the Philippines. However, political factors would offset that vulnerability in the case of Vietnam and amplify it in the case of the Philippines, making the Philippines more likely to concede to modest political demands.

  8. Sediment-Mass Accumulation Rate and Variability in the East China Sea Detected by GRACE

    Directory of Open Access Journals (Sweden)

    Ya-Chi Liu

    2016-09-01

    Full Text Available The East China Sea (ECS is a region with shallow continental shelves and a mixed oceanic circulation system allowing sediments to deposit on its inner shelf, particularly near the estuary of the Yangtze River. The seasonal northward-flowing Taiwan Warm Current and southward-flowing China Coastal Current trap sediments from the Yangtze River, which are accumulated over time at rates of up to a few mm/year in equivalent water height. Here, we use the Gravity Recovery and Climate Experiment (GRACE gravity products from three data centres to determine sediment mass accumulation rates (MARs and variability on the ECS inner shelf. We restore the atmospheric and oceanic effects to avoid model contaminations on gravity signals associated with sediment masses. We apply destriping and spatial filters to improve the gravity signals from GRACE and use the Global Land Data Assimilation System to reduce land leakage. The GRACE-derived MARs over April 2002–March 2015 on the ECS inner shelf are about 6 mm/year and have magnitudes and spatial patterns consistent with those from sediment-core measurements. The GRACE-derived monthly sediment depositions show variations at time scales ranging from six months to more than two years. Typically, a positive mass balance of sediment deposition occurs in late fall to early winter when the southward coastal currents prevail. A negative mass balance happens in summer when the coastal currents are northward. We identify quasi-biennial sediment variations, which are likely to be caused by quasi-biennial variations in rain and erosion in the Yangtze River basin. We briefly explain the mechanisms of such frequency-dependent variations in the GRACE-derived ECS sediment deposition. There is no clear perturbation on sediment deposition over the ECS inner shelf induced by the Three Gorges Dam. The limitations of GRACE in resolving sediment deposition are its low spatial resolution (about 250 km and possible contaminations by

  9. The Sea Dragon Network: Implications of the International Expansion of China's Maritime Shipping Industry

    National Research Council Canada - National Science Library

    Hugar, Wayne

    1998-01-01

    .... As a result, China's MSI is expanding faster than that of any other nation in the world. China's MSI expansion is creating regional shipping networks that increase levels of Sino-foreign trade (SFT) interdependence...

  10. Diversity, abundance and niche differentiation of ammonia-oxidizing prokaryotes in mud deposits of the eastern China marginal seas

    Directory of Open Access Journals (Sweden)

    Shaolan eYu

    2016-02-01

    Full Text Available The eastern China marginal seas are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA and bacteria (AOB were investigated in mud deposits of the South Yellow Sea (SYS and the East China Sea (ECS by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia and silicate (SiO32-, was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ15NTN and SiO32-, and nitrate and δ13C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO32-. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

  11. On the consistency of MODIS chlorophyll a products in the northern South China Sea

    Science.gov (United States)

    Shang, S. L.; Dong, Q.; Hu, C. M.; Lin, G.; Li, Y. H.; Shang, S. P.

    2014-01-01

    Chlorophyll a (Chl) concentrations derived from satellite measurements have been used in oceanographic research, for example to interpret eco-responses to environmental changes on global and regional scales. However, it is unclear how existing Chl products compare with each other in terms of accuracy and consistency in revealing temporal and spatial patterns, especially in the optically complex marginal seas. In this study, we examined three MODIS (Moderate Resolution Imaging Spectroradiometer) Chl data products that have been made available to the community by the US National Aeronautics and Space Administration (NASA) using community-accepted algorithms and default parameterization. These included the products derived from the OC3M (ocean chlorophyll three-band algorithm for MODIS), GSM (Garver-Siegel-Maritorena model) and GIOP (generalized inherent optical properties) algorithms. We compared their temporal variations and spatial distributions in the northern South China Sea. We found that the three products appeared to capture general features such as unique winter peaks at the Southeast Asian Time-series Study station (SEATS, 18° N, 116° E) and the Pearl River plume associated blooms in summer. Their absolute magnitudes, however, may be questionable in the coastal zones. Additional error statistics using field measured Chl as the truth demonstrated that the three MODIS Chl products may contain high degree of uncertainties in the study region. Root mean square error (RMSE) of the products from OC3M and GSM (on a log scale) was about 0.4 and average percentage error (ɛ) was ~ 115% (Chl between 0.05-10.41 mg m-3, n = 114). GIOP with default parameterization led to higher errors (ɛ = 329%). An attempt to tune the algorithms based on a local coastal-water bio-optical data set led to reduced errors for Chl retrievals, indicating the importance of local tuning of globally-optimized algorithms. Overall, this study points to the need of continuous improvements for

  12. Occurrence of marine algal toxins in oyster and phytoplankton samples in Daya Bay, South China Sea.

    Science.gov (United States)

    Jiang, Tao; Liu, Lei; Li, Yang; Zhang, Jing; Tan, Zhijun; Wu, Haiyan; Jiang, Tianjiu; Lu, Songhui

    2017-09-01

    The occurrence and seasonal variations of marine algal toxins in phytoplankton and oyster samples in Daya Bay (DYB), South China Sea were investigated. Two Dinophysis species, namely, D. caudata and D. acuminata complex, were identified as Okadaic acid (OA)/pectenotoxin (PTX) related species. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis demonstrated that 2.04-14.47 pg PTX2 per cell was the predominant toxin in single-cell isolates of D. caudata. D. acuminata was not subjected to toxin analysis. The occurrence of OAs in phytoplankton concentrates of net-haul sample coincided with the presence of D. accuminata complex, suggesting that this species is most likely an OA producer in this sea area. OA, dinophysistoxins-1 (DTX1), PTX2, PTX2sa, gymnodimine (GYM), homoyessotoxin (homoYTX), and domoic acid (DA) demonstrated positive results in net haul samples. To our best knowledge, this paper is the first to report the detection of GYM, DA, and homoYTX in phytoplankton samples in Chinese coastal waters. Among the algal toxins, GYM demonstrated the highest frequency of positive detections in phytoplankton concentrates (13/17). Five compounds of algal toxins, including OA, DTX1, PTX2, PTX2sa, and GYM, were detected in oyster samples. DA and homoYTX were not detected in oysters despite of positive detections for both in the phytoplankton concentrates. However, neither the presence nor absence of DA in oysters can be determined because extraction conditions with 100% methanol used to isolate toxins from oysters (recommended by the EU-Harmonised Standard Operating Procedure, 2015) would likely be unsuitable for this water-soluble toxin. In addition, transformation of DA during the digestion process of oysters may also be involved in the negative detections of this toxin. GYM exhibited the highest frequency of positive results in oysters (14/17). OAs were only detected in the hydrolyzed oyster samples. The detection rates of PTX and PTX2sa in

  13. Connection of the proto-Yangtze River to the East China Sea traced by sediment magnetic properties

    Science.gov (United States)

    Liu, Xianbin; Chen, Jing; Maher, Barbara A.; Zhao, Baocheng; Yue, Wei; Sun, Qianli; Chen, Zhongyuan

    2018-02-01

    The evolution of the Yangtze River, and specifically how and when it connected to the East China Sea, has been hotly debated with regard to possible linkages with the so-called 'Cenozoic Topographic Reversal' (tectonic tilting of continental east China in the Cenozoic) and particularly the relationship to the uplift history of the Tibetan Plateau. Resolving this key question would shed light on the development of large Asian rivers and related changes in landforms and monsoon climate during this interval. Here, we use the magnetic properties of both Plio-Quaternary sediments in the Yangtze delta and of surficial river sediments to identify a key mid-late Quaternary switch in sediment source-sink relationships. Our results reveal a fundamental shift in sediment magnetic properties at this time; the upper 145 m of sediment has magnetic mineral concentrations 5 to 10 times higher than those of the underlying late Pliocene/early Quaternary sediments. We show that the distinctive magnetic properties of the upper core sediments closely match those of surficial river sediments of the upper Yangtze basin, where the large-scale E'mei Basalt block (2.5 × 105 km2) is the dominant magnetic mineral source. This switch in sediment magnetic properties occurred at around the Jaramillo event ( 1.2-1.0 Ma), which indicates that both the westward extension of the proto-Yangtze River into the upper basin and completion of the connection to the East China Sea occurred no later than at that age.

  14. Genetic diversity and population structure of Eleutheronema rhadinum in the East and South China Seas revealed in mitochondrial COI sequences

    Science.gov (United States)

    Sun, Xinxu; Xu, Dongdong; Lou, Bao; Zhang, Tao; Xin, Jian; Guo, Yaoshi; Ma, Shilei

    2013-11-01

    Eleutheronema rhadinum is a potential commercial fisheries species and is subject to intense exploitation in China. Knowledge on the population structure of E. rhadinum in Chinese coastal waters, which is important for sustainable exploitation and proper resource management, is lacking. In the present study, the genetic diversity and population structure of E. rhadinum were evaluated using a 564-base pair fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. A total of 76 specimens were collected from three localities around the East (Qidong and Zhoushan) and South China Seas (Zhuhai). Among these individuals, nine polymorphic sites were detected and 11 distinct haplotypes were defined. High levels of haplotype diversity ( h =0.759±0.035) and low levels of nucleotide diversity ( π= 0.001 98±0.003 26) were observed in these populations. Hierarchical analysis of molecular variance (AMOVA) indicated that 96.72% of the genetic variation occurred within the populations, whereas 3.28% occurred among populations. No significant genealogical branches or clusters were recognized on the neighbor-joining tree. Intra-group variation among populations was significant ( φ st=0.032 85, P<0.01). These results suggest that E. rhadinum populations in the East and South China Seas have developed divergent genetic structures. Tests of neutral evolution and mismatch distribution suggest that E. rhadinum may have experienced a population expansion. The present study provides basic information for the conservation and sustainable exploitation of this species.

  15. Levels and spatial distribution of gaseous polychlorinated biphenyls and polychlorinated naphthalenes in the air over the northern South China Sea

    Science.gov (United States)

    Li, Qilu; Xu, Yue; Li, Jun; Pan, Xiaohui; Liu, Xiang; Zhang, Gan

    2012-09-01

    Monitoring marine persistent organic pollutants (POPs) is important because oceans play a significant role in the cycling of POPs. The South China Sea (SCS) is surrounded by developing countries in Southeast Asia which are centers of e-waste recycling and the ship dismantling industry. In this study, shipboard air samples collected over the SCS between September 6 and 22, 2005 were analyzed for polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). The levels of ∑12PCBs ranged from 32.3 to 167 pg m-3, with a mean value of 98.4 ± 36.0 pg m-3. Tetra-CBs were the predominant congeners. The concentrations of ∑18PCNs ranged from N.D. to 26.0 pg m-3, with a mean value of 10.5 ± 7.16 pg m-3, and tri-CNs were predominant. The gaseous concentrations of PCBs and PCNs over the SCS were consistent with those over other seas and oceans. Compared with previous studies, it was found that the concentrations of PCBs exhibited an obviously declining trend. The measured PCB and PCN concentrations in the atmosphere over the SCS were influenced by their proximity to source regions and air mass origins. The highest gaseous PCB and PCN concentrations were found at sampling sites adjacent to the continental South China. E-waste recycling, ship dismantling and combustion in South China and some Southeast Asian countries might contribute PCBs and PCNs to the atmosphere of the SCS.

  16. Bioactive new metabolites from the green alga Udotea orientalis growing on the Gorgonian coral Pseudopterogorgia rigida.

    Science.gov (United States)

    Sabry, Omar M M; Goeger, Douglas E; Gerwick, William H

    2017-06-01

    As part of our continued search for bioactive secondary metabolites from marine sources using a bioassay-guided fractionation technique (Cytotoxic and anti-trypanosome activities), we have examined the organic extract of Papua New Guinean collection of the green alga Udotea orientalis growing on the Gorgonian coral Pseudopterogorgia rigida. Successive HPLC investigations resulted in isolation of three new compounds, (+) curcuepoxide A, (+) curcuepoxide B and (+)-10α-hydroxycurcudiol. Analysis of different spectroscopic data e.g. UV, IR, LRMS, HRMS, 1D NMR and 2D NMR on the isolated compounds allowed for construction of the planar structures. Stereochemistry assignment at C-7 and C-10 in the new compounds was discussed. Isolated compounds were found to be active in an in vitro assay of antitrypanosome activity. The isolated compounds were found to have variable cytotoxic activity in human lung cancer cell lines.

  17. The MARINA model (Model to Assess River Inputs of Nutrients to seAs): Model description and results for China.

    Science.gov (United States)

    Strokal, Maryna; Kroeze, Carolien; Wang, Mengru; Bai, Zhaohai; Ma, Lin

    2016-08-15

    Chinese agriculture has been developing fast towards industrial food production systems that discharge nutrient-rich wastewater into rivers. As a result, nutrient export by rivers has been increasing, resulting in coastal water pollution. We developed a Model to Assess River Inputs of Nutrients to seAs (MARINA) for China. The MARINA Nutrient Model quantifies river export of nutrients by source at the sub-basin scale as a function of human activities on land. MARINA is a downscaled version for China of the Global NEWS-2 (Nutrient Export from WaterSheds) model with an improved approach for nutrient losses from animal production and population. We use the model to quantify dissolved inorganic and organic nitrogen (N) and phosphorus (P) export by six large rivers draining into the Bohai Gulf (Yellow, Hai, Liao), Yellow Sea (Yangtze, Huai) and South China Sea (Pearl) in 1970, 2000 and 2050. We addressed uncertainties in the MARINA Nutrient model. Between 1970 and 2000 river export of dissolved N and P increased by a factor of 2-8 depending on sea and nutrient form. Thus, the risk for coastal eutrophication increased. Direct losses of manure to rivers contribute to 60-78% of nutrient inputs to the Bohai Gulf and 20-74% of nutrient inputs to the other seas in 2000. Sewage is an important source of dissolved inorganic P, and synthetic fertilizers of dissolved inorganic N. Over half of the nutrients exported by the Yangtze and Pearl rivers originated from human activities in downstream and middlestream sub-basins. The Yellow River exported up to 70% of dissolved inorganic N and P from downstream sub-basins and of dissolved organic N and P from middlestream sub-basins. Rivers draining into the Bohai Gulf are drier, and thus transport fewer nutrients. For the future we calculate further increases in river export of nutrients. The MARINA Nutrient model quantifies the main sources of coastal water pollution for sub-basins. This information can contribute to formulation of

  18. Phytoplankton diversity in the East China Sea and Yellow Sea measured by PCR-DGGE and its relationships with environmental factors

    Science.gov (United States)

    Sun, Jing; Yu, Zhigang; Gao, Yahui; Zhou, Qianqian; Zhen, Yu; Chen, Hongtao; Zhao, Liyuan; Yao, Qingzhen; Mi, Tiezhu

    2010-03-01

    Relationships between phytoplankton community composition and environmental variables in the East China Sea (ECS) and Yellow Sea (YS) were investigated using geochemical and molecular microbiology methods. The diversity of phytoplankton was characterized using cultivation-independent PCR-based denaturing gradient gel electrophoresis (DGGE). Groups resulting from unweighted pair-group method with arithmetic averages clustering of the DGGE profiles showed good consistency with the eco-environmental characteristics of the sea area they belonged to. Additionally, the clustering results based on DGGE fingerprinting and those based on morphological compositions were practically identical. The relationship of phytoplankton diversity to environmental factors was statistically analyzed. Temperature, dissolved inorganic nitrogen (DIN), and silicate-Si were found significantly related to the phytoplankton community composition. Canonical correspondence analysis (CCA) was performed to reveal the relationship between community composition and these three environmental factors. Generally, values of the ECS are clearly separated from those of the YS in the CCA biplot, due to mainly the effect of temperature and DIN.

  19. Organochlorine pesticide contamination in marine organisms of Yantai coast, northern Yellow Sea of China.

    Science.gov (United States)

    Chen, Jing; Chen, Linlin; Liu, Dongyan; Zhang, Gaosheng

    2014-03-01

    To evaluate the contamination of organochlorine pesticides (OCPs) in marine organisms and their potential health risk on consumers in the northern Yellow Sea of China, mollusks, wild shrimps, and crabs were collected from the Yantai coast, and the OCP contents in the samples were analyzed and compared. The results indicate that all the samples have been contaminated by OCPs, and OCP concentrations varied in individual species and in sampling sites. Among the studied OCPs, ∑HCH and ∑DDT concentrations ranged from 0.91 to 13.92 ng g(-1) and from 10.16 to 411.19 ng g(-1), respectively. Meretrix was highly enriched with HCHs, while the highest DDT concentration was found in Crassostrea. For the OCP isomers, β-HCH was the predominant isomer of HCHs, and p,p'-DDE concentration was much higher than other isomers of DDTs. The concentrations of other OCPs (HCB, t-CHL, endrin, and mirex) were relatively low. For the shrimp and crab samples, Alpheus distinguendus samples accumulated a higher level of HCHs but lower DDTs than Oratosquilla aratoria and Carcinoplax vestitus in all sampling areas. HCHs in the samples of contrast area were not significantly lower than that of the sewage outfall area and port area, whereas DDTs in the samples of contrast area were relatively lower than that of the other two areas. Generally, all the OCP contents in the samples are in the range of the edible hygienic criteria except the total concentration of DDTs in Crassostrea.

  20. Observed near-inertial kinetic energy in the northwestern South China Sea

    Science.gov (United States)

    Chen, Gengxin; Xue, Huijie; Wang, Dongxiao; Xie, Qiang

    2013-10-01

    Based on more than 3 years of moored current-meter records, this study examined seasonal variability of near-inertial kinetic energy (NIKE) as well as all large (greater than one standard deviation from the mean) NIKE events related to storms and eddies in the northwestern South China Sea. The NIKE in the subsurface layer (30-450 m) exhibited obvious seasonal variability with larger values in autumn (herein defined as August, September, and October). All large NIKE events during the observation period were generated by passing storms. Most of the NIKE events had an e-folding timescale longer than 7 d. The phase velocity, vertical wavelength, and frequency shift of these events were examined. The maximum NIKE, induced by typhoon "Neoguri," was observed in April 2008. Normal mode analysis suggested that the combined effects of the first four modes determined the vertical distribution of NIKE with higher NIKE below 70 m but lower NIKE from 30 to 70 m. Another near-inertial oscillation event observed in August 2007 had the longest e-folding timescale of 13.5 d. Moreover, the NIKE propagated both upward and downward during this event. A ray-tracing model indicated that the smaller Brunt-Väisälä frequency and the stronger vertical shear of horizontal currents in an anticyclonic eddy and the near-inertial wave with larger horizontal scale facilitated the unusual propagation of the NIKE and the long decay timescale. Although the NIKE originated from wind, the water column structure affected by diverse oceanographic processes contributed substantially to its complex propagation and distribution.

  1. Origins of terrestrial organic matter in surface sediments of the East China Sea shelf

    Science.gov (United States)

    Zhang, Hailong; Xing, Lei; Zhao, Meixun

    2017-10-01

    Terrestrial organic matter (TOM) is an important component of marine sedimentary OM, and revealing the origins and transport mechanisms of TOM to the East China Sea (ECS) is important for understanding regional carbon cycle. A novel approach combining molecular proxies and compound-specific carbon isotopes is used to quantitatively constrain the origins and transport mechanisms of TOM in surface sediments from the ECS shelf. The content of terrestrial biomarkers of (C27+C29+C31) n-alkanes (52 to 580 ng g-1) revealed a seaward decreasing trend, the δ13CTOC values (-20.6‰ to -22.7‰) were more negative near the coast, and the TMBR (terrestrial and marine biomarker ratio) values (0.06 to 0.40) also revealed a seaward decreasing trend. These proxies all indicated more TOM (up to 48%) deposition in the coastal areas. The Alkane Index, the ratio of C29/(C29+C31) n-alkanes indicated a higher proportion of grass vegetation in the coastal area; While the δ13C values of C29 n-alkane (-29.3‰ to -33.8‰) indicated that terrestrial plant in the sediments of the ECS shelf were mainly derived from C3 plants. Cluster analysis afforded detailed estimates of different-sourced TOM contributions and transport mechanisms. TOM in the Zhejiang-Fujian coastal area was mostly delivered by the Changjiang River, and characterized by higher %TOM (up to 48%), higher %C3 plant OM (68%-85%) and higher grass plant OM (56%-61%); TOM in the mid-shelf area was mostly transported by aerosols, and characterized by low %TOM (less than 17%), slightly lower C3 plant OM (56%-72%) and lower grass plant OM (49%-55%).

  2. Submarine landslide identified in DLW3102 core of the northern continental slope, South China Sea

    Science.gov (United States)

    Xu, Yuanqin; Liu, Lejun; Zhou, Hang; Huang, Baoqi; Li, Ping; Ma, Xiudong; Dong, Feiyin

    2018-02-01

    In this paper, we take DLW3101 core obtained at the top of the canyon (no landslide area) and DLW3102 core obtained at the bottom of the canyon (landslide area) on the northern continental slope of the South China Sea as research objects. The chronostratigraphic framework of the DLW3101 core and elemental strata of the DLW3101 core and the DLW3102 core since MIS5 are established by analyzing oxygen isotope, calcium carbonate content, and X-Ray Fluorescence (XRF) scanning elements. On the basis of the information obtained by analyzing the sedimentary structure and chemical elements in the landslide deposition, we found that the DLW3102 core shows four layers of submarine landslides, and each landslide layer is characterized by high Si, K, Ti, and Fe contents, thereby indicating terrigenous clastic sources. L1 (2.15-2.44 m) occurred in MIS2, which is a slump sedimentary layer with a small sliding distance and scale. L2 (15.48-16.00 m) occurred in MIS5 and is a debris flow-deposited layer with a scale and sliding distance that are greater than those of L1. L3 (19.00-20.90 m) occurred in MIS5; its upper part (19.00-20.00 m) is a debris flow-deposited layer, and its lower part (20.00-20.90 m) is a sliding deposition layer. The landslide scale of L3 is large. L4 (22.93-24.27 m) occurred in MIS5; its upper part (22.93-23.50 m) is a turbid sedimentary layer, and its lower part (23.50-24.27 m) is a slump sedimentary layer. The landslide scale of L4 is large.

  3. Coral trace metal of natural and anthropogenic influences in the northern South China Sea.

    Science.gov (United States)

    Jiang, Wei; Yu, Ke-Fu; Song, Yin-Xian; Zhao, Jian-Xin; Feng, Yue-Xing; Wang, Ying-Hui; Xu, Shen-Dong

    2017-12-31

    The composition and concentrations of trace metals in coastal seawater have changed in parallel with variations in geochemical processes, climate and anthropogenic activities. To evaluate the response of trace metals in coastal seawater to climatic changes and human disturbances, we report annual-resolution trace element data for a Porites coral core covering ~100years of continuous growth from a fringing reef in Xiaodonghai Bay in the northern South China Sea. The results suggested that the trace metal contents in the coral skeleton demonstrated decadal to interdecadal fluctuations with several large or small peaks in certain years with remarkable environmental significances. All of the trace metals in coastal surface seawater, especially Cr and Pb (related to industrial or traffic emissions), were impacted by terrestrial inputs, except for Sr and U, which were impacted by the surface seawater temperature (SST). Moreover, Mn, Ni, Fe and Co were also contributed by weapons and military supplies during wars, and Cu, Cd and Zn were further impacted by upwelling associated with their biogeochemical cycles. Ba and rare earth element (REE) in coastal surface seawater were dominated by runoff and groundwater discharge associated with precipitation. This study provided the potential for some trace metals (e.g., REE, Ba, Cu, Cd, and Zn) in coral skeletons to be used as proxies of natural (e.g., upwelling and precipitation) and anthropogenic (e.g., war and coastal construction) variability of seawater chemistry to enable the reconstruction of environmental and climatic changes through time. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Deltaic Depositional Systems, Evolution Characteristics, and Petroleum Potential, Palaeogene Sub-Basin, South China Sea

    Science.gov (United States)

    Li, Yuan; Wang, Hua; Zhang, Guotao

    2015-04-01

    Deltaic depositional systems are detailed characterized by morphology and facies in a Palaeogene continental sub-basin of Beibuwan Basin, South China Sea. Based on examination of 435 m of conventional cores from 30 wells, three major types of deltaic facies have been recognized: delta, beach and shoreface. Morphology and facies asymmetry between the down-drift and the up-drift sides present a typical asymmetric delta system:1) the down-rift, sourced primarily by the feeding river, are influenced by mixed river and wave processes. Deposits on this side are muddy and consist of barrier, bar, bay-fill, and bayhead delta facies with variable bioturbation intensity; 2)the up-rift, in contrast, is sourced by a second sediment source and typically consists of laterally continuous sandy beach and shoreface facies. Finally, two fundamentally different depositional models are established and reflect a different style of sequence stratigraphic patterns: 1) Multiple-stage faults slopes developed in the down-rift side feed fine grained sediment into two stages channelized front deltaic system; 2) Flexure slope break of the up-rift side, combining with deeper gradual slopes, conversely, feed coarser grained sediment from larger drainages into sandy beach and shoreface systems. Such a distinction has well explained the differentiation of the proven hydrocarbon reserves because the up-rift consists of well-sorted, mature, and laterally continuous homogeneous beach-shoreface reservoirs, whereas the down-rift, in contrast, is muddier and consists of less continuous, less mature, heterolithic reservoirs. The Delta asymmetry concepts and models don't only challenge the traditional definition of deltas in Fushan sub-basin, but also provides strong theoretical support for the future exploration. This process-based model may be applicable to many deep-water settings and provides a framework within which to interpret the stratigraphic and spatial distribution of these complex deposits.

  5. Kinematic models for the opening of the South China Sea: An upwelling divergent flow origin

    Science.gov (United States)

    Chen, Lin; Hu, Jiwei; Yang, Dinghui; Song, Haibin; Wang, Zhenhua

    2017-06-01

    We investigate the kinematics of continent breakup and seafloor spreading in response to the upwelling divergent mantle flow using the optimal nearly-analytical discrete method. Modeling results show that a larger upwelling rate (Vz) in the upwelling divergent flow system favors the earlier development of continent breakup and seafloor spreading and the formation of narrow continental rifted margins and mantle exhumation; while a larger half divergent rate (Vx) favors the diffusive lithospheric thinning and the formation of wide continental rifted margins and mantle exhumation. The upwelling divergent flow-driven continent extension is strongly depth-dependent at the proximal margins, but it behaves approximately in a depth-uniform manner at the distal margins. Application of this model to the South China Sea (SCS) demonstrates that: (1) an upwelling flow operation with Vz = 0.3 cm/yr can explain the pre-spreading continent extension of the SCS between ca. 65 Ma and ca. 33 Ma; (2) the followed upwelling divergent flow with Vx = 2.5 cm/yr and Vz = 0.3 cm/yr can reproduce the seafloor spreading history at ca. 33-16 Ma in the SCS central oceanic basin; and (3) the post-16 Ma thermal cooling since the cessation of the SCS seafloor spreading contributed ∼1.2 km to the present-day bathymetry at the relict spreading ridge. The upwelling divergent flow with a high ratio of Vx/Vz was also likely responsible for the occurrence of the very wide rifted continental margins bounded the SCS. We suggest that an upwelling divergent mantle flow played a leading role in the opening of the SCS.

  6. Utilizing 210Po deficit to constrain particle dynamics in mesopelagic water, western South China Sea

    Science.gov (United States)

    Ma, Haoyang; Yang, Weifeng; Zhang, Lihao; Zhang, Run; Chen, Min; Qiu, Yusheng; Zheng, Minfang

    2017-04-01

    The 210Po-210Pb pair is increasingly used as a proxy of quantifying organic carbon export from the euphotic zone. However, disequilibria between 210Po and 210Pb in mesopelagic water have been poorly studied. Here we present unusual deficiencies of 210Po with respect to 210Pb in mesopelagic water (200-1000 m) in the South China Sea (SCS). The total particulate matter (TPM) increased by up to 32% in the mesopelagic layer comparing with the euphotic zone. The total 210Po/210Pb ratio varied from 0.41 to 0.98 with an average of 0.72 ± 0.19, showing an enhanced removal of 210Po in mesopelagic water. On average, particulate 210Po and 210Pb increased by 23% and 32% at the slope stations, respectively. These results indicated that the 210Po deficits result from lateral transport, probably via benthic nepheloid layer. Based on the deficiency of 210Po, the residence times of particulate 210Po were estimated to range from 0.11 to 0.25 year (avg. 0.17 ± 0.07 year), allowing resuspended sediment to disperse over a long range. The export fluxes of 210Po varied from 68 to 121 dpm m-2 d-1 with an average of 96 ± 27 dpm m-2 d-1, which was 6 times that out of the euphotic zone. Using the 210Po deficits, the export fluxes of TPM out of the mesopelagic layer were quantified to vary from 4.19 to 10.20 g m-2 d-1, revealing a large amount of particles from the shelf to the SCS basin. This study suggests that 210Po-210Pb could be an effective tracer of tracking particle cycling in mesopelagic water.

  7. Spatial distribution of turbulent mixing in the upper ocean of the South China Sea

    Directory of Open Access Journals (Sweden)

    X.-D. Shang

    2017-06-01

    Full Text Available The spatial distribution of the dissipation rate (ε and diapycnal diffusivity (κ in the upper ocean of the South China Sea (SCS is presented from a measurement program conducted from 26 April to 23 May 2010. In the vertical distribution, the dissipation rates below the surface mixed layer were predominantly high in the thermocline where shear and stratification were strong. In the regional distribution, high dissipation rates and diapycnal diffusivities were observed in the region to the west of the Luzon Strait, with an average dissipation rate and diapycnal diffusivity of 8.3  ×  10−9 W kg−1 and 2.7  ×  10−5 m2 s−1, respectively, almost 1 order of magnitude higher than those in the central and southern SCS. In the region to the west of the Luzon Strait, the water column was characterized by strong shear and weak stratification. Elevated dissipation rates (ε > 10−7 W kg−1 and diapycnal diffusivities (κ > 10−4 m2 s−1, induced by shear instability, occurred in the water column. In the central and southern SCS, the water column was characterized by strong stratification and weak shear and the turbulent mixing was weak. Internal waves and internal tides generated near the Luzon Strait are expected to make a dominant contribution to the strong turbulent mixing and shear in the region to the west of the Luzon Strait. The observed dissipation rates were found to scale positively with the shear and stratification, which were consistent with the MacKinnon–Gregg model used for the continental shelf but different from the Gregg–Henyey scaling used for the open ocean.

  8. Spatial distribution of turbulent mixing in the upper ocean of the South China Sea

    Science.gov (United States)

    Shang, Xiao-Dong; Liang, Chang-Rong; Chen, Gui-Ying

    2017-06-01

    The spatial distribution of the dissipation rate (ɛ) and diapycnal diffusivity (κ) in the upper ocean of the South China Sea (SCS) is presented from a measurement program conducted from 26 April to 23 May 2010. In the vertical distribution, the dissipation rates below the surface mixed layer were predominantly high in the thermocline where shear and stratification were strong. In the regional distribution, high dissipation rates and diapycnal diffusivities were observed in the region to the west of the Luzon Strait, with an average dissipation rate and diapycnal diffusivity of 8.3 × 10-9 W kg-1 and 2.7 × 10-5 m2 s-1, respectively, almost 1 order of magnitude higher than those in the central and southern SCS. In the region to the west of the Luzon Strait, the water column was characterized by strong shear and weak stratification. Elevated dissipation rates (ɛ > 10-7 W kg-1) and diapycnal diffusivities (κ > 10-4 m2 s-1), induced by shear instability, occurred in the water column. In the central and southern SCS, the water column was characterized by strong stratification and weak shear and the turbulent mixing was weak. Internal waves and internal tides generated near the Luzon Strait are expected to make a dominant contribution to the strong turbulent mixing and shear in the region to the west of the Luzon Strait. The observed dissipation rates were found to scale positively with the shear and stratification, which were consistent with the MacKinnon-Gregg model used for the continental shelf but different from the Gregg-Henyey scaling used for the open ocean.

  9. Rift-drift transition in the Dangerous Grounds, South China Sea

    Science.gov (United States)

    Peng, Xi; Shen, Chuanbo; Mei, Lianfu; Zhao, Zhigang; Xie, Xiaojun

    2018-04-01

    The South China Sea (SCS) has a long record of rifting before and after subsequent seafloor spreading, affecting the wide continent of the Dangerous Grounds, and its scissor-shape opening manner results in the rifting structures that vary along this margin. Some 2000 km of regional multichannel seismic data combined with borehole and dredge data are interpreted to analyze the multistage rifting process, structural architecture and dynamic evolution across the entire Dangerous Grounds. Key sequence boundaries above the Cenozoic basement are identified and classified into the breakup unconformity and the rift end unconformity, which consist of the rift-related unconformities. Reflector T70 in the east of the Dangerous Grounds represents the breakup unconformity, which is likely corresponding to the spreading of the East Subbasin. T60 formed on the top of carbonate platform is time equivalent to the spreading of the Southwest Subbasin, marking the breakup unconformity of the central Dangerous Grounds. The termination of the spreading of the SCS is manifested by the rift end unconformity of T50 in the southwest and the final rift occurring in the northwest of the Dangerous Grounds is postponed to the rift end unconformity of T40. On the basis of the stratigraphic and structural analysis, distinct segments in the structural architecture of the syn-rift units and the ages of rift-drift transition show obvious change from the proximal zone to the distal zone. Three domains, which are the Reed Bank-Palawan Rift domain, the Dangerous Grounds Central Detachment domain and Nam Con Son Exhumation domain, reflect the propagation of the margin rifting developed initially by grabens formed by high angle faults, then large half-grabens controlled by listric faults and detachments and finally rotated fault blocks in the hyper-extended upper crust associated with missing lower crust or exhumed mantle revealing a migration and stepwise rifting process in the south margin of the SCS.

  10. Wave climate simulation for southern region of the South China Sea

    Science.gov (United States)

    Mirzaei, Ali; Tangang, Fredolin; Juneng, Liew; Mustapha, Muzneena Ahmad; Husain, Mohd Lokman; Akhir, Mohd Fadzil

    2013-08-01

    This study investigates long-term variability and wave characteristic trends in the southern region of the South China Sea (SCS). We implemented the state-of-the art WAVEWATCH III spectral wave model to simulate a 31-year wave hindcast. The simulation results were used to assess the inter-annual variability and long-term changes in the SCS wave climate for the period 1979 to 2009. The model was forced with Climate Forecast System Reanalysis winds and validated against altimeter data and limited available measurements from an Acoustic Wave and Current recorder located offshore of Terengganu, Malaysia. The mean annual significant wave height and peak wave period indicate the occurrence of higher wave heights and wave periods in the central SCS and lower in the Sunda shelf region. Consistent with wind patterns, the wave direction also shows southeasterly (northwesterly) waves during the summer (winter) monsoon. This detailed hindcast demonstrates strong inter-annual variability of wave heights, especially during the winter months in the SCS. Significant wave height correlated negatively with Niño3.4 index during winter, spring and autumn seasons but became positive in the summer monsoon. Such correlations correspond well with surface wind anomalies over the SCS during El Nino events. During El Niño Modoki, the summer time positive correlation extends northeastwards to cover the entire domain. Although significant positive trends were found at 95 % confidence levels during May, July and September, there is significant negative trend in December covering the Sunda shelf region. However, the trend appears to be largely influenced by large El Niño signals.

  11. Temporal and spatial distribution of the meiobenthic community in Daya Bay, South China Sea

    Science.gov (United States)

    Tang, L.; Li, H. X.; Yan, Y.

    2012-04-01

    Spatial and temporal biodiversity patterns of the meiobenthos were studied for the first time in Daya Bay, which is a tropical semi-enclosed basin located in the South China Sea. The abundance, biomass, and composition of the meiobenthos and the basic environmental factors in the bay were investigated. The following 19 taxonomic groups were represented in the meiofauna: Nematoda, Copepoda, Polychaeta, Oligochaeta, Kinorhyncha, Gastrotricha, Ostracoda, Bivalvia, Turbellaria, Nemertinea, Sipuncula, Hydroida, Amphipoda, Cumacea, Halacaroidea, Priapulida, Echinodermata, Tanaidacea, and Rotifera. Total abundance and biomass of the meiobenthos showed great spatial and temporal variation, with mean values of 993.57 ± 455.36 ind cm-2 and 690.51 ± 210.64 μg 10 cm-2, respectively. Nematodes constituted 95.60 % of the total abundance and thus had the greatest effect on meiofauna quantity and distribution, followed by copepods (1.55 %) and polychaetes (1.39 %). Meiobenthos abundance was significantly negatively correlated with water depth at stations (r=-0.747, P<0.05) and significantly negatively correlated with silt-clay content (r=-0.516, P<0.01) and medium diameter (r=-0.499, P<0.01) of the sediment. Similar results were found for correlations of biomass and abundance of nematodes with environmental parameters. Polychaete abundance was positively correlated with the bottom water temperature (r=0.456, P<0.01). Meiobenthos abundance differed significantly among seasons (P<0.05), although no significant difference among stations and the interaction of station × season was detected by two-way ANOVA. In terms of vertical distribution, most of the meiobenthos was found in the surface layer of sediment. This pattern was apparent for nematodes and copepods, but a vertical distribution pattern for polychaetes was not as obvious. Based on the biotic indices and analyses of their correlations and variance, the diversity of this community was likely to be influenced by

  12. Isolation, structure, and surfactant properties of polysaccharides from Ulva lactuca L. from South China Sea.

    Science.gov (United States)

    Tian, Hua; Yin, Xueqiong; Zeng, Qinghuan; Zhu, Li; Chen, Junhua

    2015-08-01

    Two polysaccharides (ULP1 and ULP2) were isolated through ultrasonic-assisted extraction from green seaweed Ulva lactuca L. which was collected from the South China Sea. The highest yield of 17.57% was obtained under the conditions of 2% NaOH, 90 °C, material/water mass ratio 1:80, liquid extraction 5h and subsequent ultrasound-assisted extraction 1h. The structure of ULPs were characterized with periodate oxidation followed by Smith degradation, (1)H NMR, (13)C NMR spectroscopy, FTIR, and GPC. The molecular weights of ULP1 and ULP2 were 189 kDa and 230 kDa, respectively. The structural characteristics of ULP1 and ULP2 were quite similar. They were composed of rhamnose, xylose, glucose, and glucuronic acid. The content of rhamnose, xylose, glucose, glucuronic acid, sulfate was 51.2%, 12.3%, 20.1%, 16.4%, 12.0% for ULP1, respectively, and 60.8%, 14.2%, 8.2%, 16.8%, 26.8%, respectively, for ULP2. Both ULP1 and ULP2 showed good surface activity. 5 mg/mL ULP1 (2.62×10(-2) mmol/L) decreased the water surface tension to 51.63 mN/m. The critical micellar concentration of ULP1 and ULP2 was 1.01 mg/mL (5.3×10(-3) mmol/L) and 1.14 mg/mL (5.0×10(-3) mmol/L), respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from MIRAI in the East China Sea, Japan Sea and others from 2005-10-31 to 2006-01-30 (NODC Accession 0109919)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109919 includes chemical, discrete sample, physical and profile data collected from MIRAI in the East China Sea (Tung Hai), Japan Sea, North Pacific...

  14. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the KAIYO-MARU in the East China Sea (Tung Hai) and Philippine Sea from 1996-06-20 to 1996-07-15 (NODC Accession 0115023)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115023 includes chemical, discrete sample, physical and profile data collected from KAIYO-MARU in the East China Sea (Tung Hai) and Philippine Sea...

  15. Partial pressure (or fugacity) of carbon dioxide and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from RYOFU MARU in the Bismarck Sea, East China Sea and others from 1989-11-17 to 1992-03-09 (NCEI Accession 0157056)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157056 includes Surface underway, chemical, meteorological and physical data collected from RYOFU MARU in the Bismarck Sea, East China Sea (Tung...

  16. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from RYOFU MARU in the Bismarck Sea, East China Sea and others from 1989-11-17 to 1995-03-07 (NCEI Accession 0156927)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0156927 includes Surface underway, chemical, meteorological and physical data collected from RYOFU MARU in the Bismarck Sea, East China Sea (Tung...

  17. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from OCEAN RESEARCHER I in the Philippine Sea and South China Sea from 1991-07-08 to 1991-07-12 (NCEI Accession 0143948)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0143948 includes discrete sample and profile data collected from OCEAN RESEARCHER I in the Philippine Sea and South China Sea (Nan Hai) from...

  18. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from KEIFU MARU in the East China Sea, Japan Sea and others from 2012-10-24 to 2013-08-27 (NODC Accession 0116977)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116977 includes Surface underway, chemical, meteorological and physical data collected from KEIFU MARU in the East China Sea (Tung Hai), Japan Sea,...

  19. Satellite remote sensing of a low-salinity water plume in the East China Sea

    Directory of Open Access Journals (Sweden)

    Y. H. Ahn

    2008-07-01

    Full Text Available With the aim to map and monitor a low-salinity water (LSW plume in the East China Sea (ECS, we developed more robust and proper regional algorithms from large in-situ measurements of apparent and inherent optical properties (i.e. remote sensing reflectance, Rrs, and absorption coefficient of coloured dissolved organic matter, aCDOM determined in ECS and neighboring waters. Using the above data sets, we derived the following relationships between visible Rrs and absorption by CDOM, i.e. Rrs (412/Rrs (555 vs. aCDOM (400 (m−1 and aCDOM (412 (m−1 with a correlation coefficient R2 0.67 greater than those noted for Rrs (443/Rrs (555 and Rrs (490/Rrs (555 vs. aCDOM (400 (m−1 and aCDOM (412 (m−1. Determination of aCDOM (m−1 at 400 nm and 412 nm is particularly necessary to describe its absorption as a function of wavelength λ using a single exponential model in which the spectral slope S as a proxy for CDOM composition is estimated by the ratio of aCDOM at 412 nm and 400 nm and the reference is explained simply by aCDOM at 412 nm. In order to derive salinity from the absorption coefficient of CDOM, in-situ measurements of salinity made in a wide range of water types from dense oceanic to light estuarine/coastal systems were used along with in-situ measurements of aCDOM at 400 nm, 412 nm, 443 nm and 490 nm. The CDOM absorption at 400 nm was better inversely correlated (R2=0.86 with salinity than at 412 nm, 443 nm and 490 nm (R2=0.85–0.66, and this correlation corresponded best with an exponential (R2=0.98 rather than a linear function of salinity measured in a variety of water types from this and other regions. Validation against a discrete in-situ data set showed that empirical algorithms derived from the above relationships could be successfully applied to satellite data over the range of water types for which they have been developed. Thus, we applied these algorithms to a series of SeaWiFS images for the derivation of CDOM and salinity

  20. Halogenated organic pollutants in marine biota from the Xuande Atoll, South China Sea: Levels, biomagnification and dietary exposure.

    Science.gov (United States)

    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.

  1. Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea

    International Nuclear Information System (INIS)

    Cai Minghong; Zhao Zhen; Yang Haizhen; Yin Zhigao; Hong Qingquan; Sturm, Renate; Ebinghaus, Ralf; Ahrens, Lutz; Cai Minggang; He, Jianfeng; Xie Zhiyong

    2012-01-01

    The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(−)ESI-MS/MS). Concentrations of 9 PFCs, including C 4 and C 8 (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C 5 –C 9 and C 13 (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The ΣPFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5–1541 pg/L), PFBS (23.0–941 pg/L) and PFHpA (0–422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study. - Highlights: ► Concentrations of various ionic PFCs were firstly quantified in coastal waters of China Sea for the first time. ► PFOA and PFBS, PFHxA, PFNA, PFOS, PFHpA were positively correlated which indicates that the same sources. ► The result of this study is useful for global transport models of PFCs. - Concentrations of 9 PFCs were quantified in coastal waters from the East to South China Sea for the first time.

  2. Interannual variation of rare earth element abundances in corals from northern coast of the South China Sea and its relation with sea-level change and human activities

    Science.gov (United States)

    Liu, Yajing; Peng, Z.; Wei, G.; Chen, T.; Sun, W.; He, J.; Liu, Gaisheng; Chou, C.-L.; Shen, C.-C.

    2011-01-01

    Here we present interannual rare earth element (REE) records spanning the last two decades of the 20th century in two living Porites corals, collected from Longwan Bay, close to the estuarine zones off Wanquan River of Hainan Island and Hong Kong off the Pearl River Delta of Guangdong Province in the northern South China Sea. The results show that both coral REE contents (0.5-40 ng g-1 in Longwan Bay and 2-250 ng g-1 in Hong Kong for La-Lu) are characterized with a declining trend, which are significantly negative correlated with regional sea-level rise (9.4 mm a-1 from 1981 to 1996 in Longwan Bay, 13.7 mm a-1 from 1991 to 2001 in Hong Kong). The REE features are proposed to be resulted from seawater intrusion into the estuaries in response to contemporary sea-level rise. However, the tendency for the coral Er/Nd time series at Hong Kong site is absent and there is no significant relation between Er/Nd and total REEs as found for the coral at Longwan Bay site. The observations are likely attributed to changes of the water discharge and sediment load of Pearl River, which have been significantly affected by intense human activities, such as the construction of dams/reservoirs and riverbed sediment mining, in past decades. The riverine sediment load/discharge ratio of the Pearl River decreased sharply with a rate of 0.02 kg m-3 a-1, which could make significant contribution to the declining trend of coral REE. We propose that coastal corals in Longwan Bay and similar unexplored sites with little influences of river discharge and anthropogenic disruption are ideal candidates to investigate the influence of sea-level change on seawater/coral REE. ?? 2010 Elsevier Ltd.

  3. Free and Forced Rossby Waves in the Western South China Sea Inferred from Jason-1 Satellite Altimetry Data

    Directory of Open Access Journals (Sweden)

    Dongxiao Wang

    2008-06-01

    Full Text Available Data from a subsurface mooring deployed in the western South China Sea shows clear intra-seasonal oscillations (ISO at the period of 40~70 days. Analysis of remotelysensed sea surface height (SSH anomalies in the same area indicates that these ISO signals propagate both eastward and westward. Time-longitude diagrams of ISO signals in SSH anomalies and wind-stress curl indicate that the eastward propagating SSH anomalies is forced by wind-stress curl. This is also confirmed by lag correlation between SSH anomalies and the wind-stress-curl index (wind stress curl averaged over 109.5ºE -115ºE and 12ºN -13.5ºN. Lag correlation of SSH anomaly suggests that the westward propagating signals are free Rossby waves.

  4. Genetic diversity in two Japanese flounder populations from China seas inferred using microsatellite markers and COI sequences

    Science.gov (United States)

    Xu, Dongdong; Li, Sanlei; Lou, Bao; Zhang, Yurong; Zhan, Wei; Shi, Huilai

    2012-07-01

    Japanese flounder is one of the most important commercial species in China; however, information on the genetic background of natural populations in China seas is scarce. The lack of genetic data has hampered fishery management and aquaculture development programs for this species. In the present study, we have analyzed the genetic diversity in natural populations of Japanese flounder sampled from the Yellow Sea (Qingdao population, QD) and East China Sea (Zhoushan population, ZS) using 10 polymorphic microsatellite loci and cytochrome c oxidase subunit I (COI) sequencing data. A total of 68 different alleles were observed over 10 microsatellite loci. The total number of alleles per locus ranged from 2 to 9, and the number of genotypes per locus ranged from 3 to 45. The observed heterozygosity and expected heterozygosity in QD were 0.733 and 0.779, respectively, and in ZS the heterozygosity values were 0.708 and 0.783, respectively. Significant departures from Hardy-Weinberg equilibrium were observed in 7 of the 10 microsatellite loci in each of the two populations. The COI sequencing analysis revealed 25 polymorphic sites and 15 haplotypes in the two populations. The haplotype diversity and nucleotide diversity in the QD population were 0.746±0.072 8 and 0.003 34±0.001 03 respectively, and in ZS population the genetic diversity values were 0.712±0.047 0 and 0.003 18±0.000 49, respectively. The microsatellite data ( F st =0.048 7, P <0.001) and mitochondrial DNA data ( F st =0.128, P <0.001) both revealed significant genetic differentiation between the two populations. The information on the genetic variation and differentiation in Japanese flounder obtained in this study could be used to set up suitable guidelines for the management and conservation of this species, as well as for managing artificial selection programs. In future studies, more geographically diverse stocks should be used to obtain a deeper understanding of the population structure of Japanese

  5. Complete genome sequence of Paracoccus marcusii phage vB_PmaS-R3 isolated from the South China Sea

    OpenAIRE

    Xu, Yongle; Zhang, Rui; Jiao, Nianzhi

    2015-01-01

    Paracoccus spp. are isolated from both terrestrial and aquatic habitats, indicating their ubiquitous existence in the environment. Here we present the first phage isolated from this genus, vB_PmaS-R3, and its complete genome sequence. Paracoccus phage vB_PmaS-R3 is a siphophage isolated from the South China Sea. The genome sequence is 42,093?bp, with a G?+?C content of 56.36?%. Fifty-two open reading frames were predicted from the genome. The genome can mainly be divided into three regions: g...

  6. Galatheid and chirostylid crustaceans (Decapoda: Anomura) from a cold seep environment in the northeastern South China Sea.

    Science.gov (United States)

    Dong, Dong; Li, Xinzheng

    2015-12-09

    Six species of squat lobsters from a cold seep field in the northeastern South China Sea are studied. Two new species, Uroptychus jiaolongae n. sp. and U. spinulosus n. sp., are described, and their distinctions from the related species are detailed. Two species, Munidopsis tuberosa Osawa, Lin & Chan, 2008 and M. verrilli Benedict, 1902, are herein reported for the first time from a cold seep/hydrothermal vent environment. The number of squat lobsters species associated with those chemosynthetic environments now stands at forty-one.

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

    Science.gov (United States)

    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

  8. The evolution of stenols and stanols in marine sediment core from Beibu Bay, the South China Sea

    Science.gov (United States)

    Jiang, Shanchun; Jia, Rongfen; Luan, Zuofeng

    1992-03-01

    Ten stenols and stanols were identified by TLC, GC and GC-MS-DS in a marine sediment core from Beibu Bay, the South China Sea. C27, C28 and C29 Δ5 stenols and 5α-stanols mainly come from zooplankton, algae and phytoplankton in marine environment. C29 24-ethylcholest-5-en-3β-ol is thought to indicate input of terrigenous organic matter. The increase of C27, C28 and C29 5α-stanol/Δ5 stenol ratios with sediment depth shows the evolution of stenols and stanols in the marine sediment core.

  9. Distribution of tetraether lipids in surface sediments of the northern South China Sea: Implications for TEX86 proxies

    Directory of Open Access Journals (Sweden)

    Huangmin Ge

    2013-03-01

    Full Text Available Archaea have unique glycerol dialkyl glycerol tetraether (GDGT lipids that can be used to develop paleotemperature proxies such as TEX86. This research is to validate proposed GDGT-proxies for paleotemperature determination in the South China Sea (SCS. Samples were collected from core-top sediments (0–5 cm in the northern SCS. Total lipids were extracted to obtain core GDGTs, which were identified and quantified using liquid chromatography-mass spectrometry (LC-MS. The abundance of isoprenoidal GDGTs (iGDGTs ranged from 271.5 ng/g dry sediment to 1266.3 ng/g dry sediment, whereas the branched GDGTs (bGDGTs, supposedly derived from terrestrial sources, ranged from 22.2 ng/g dry sediment to 56.7 ng/g dry sediment. The TEX86-derived sea surface temperatures ranged from 20.9 °C in the coast (water depth  1000 m. TEX86-derived temperatures near shore (<160 m water depth averaged 23.1 ± 2.5 °C (n = 4, which were close to the satellite-derived winter mean sea surface temperature (average 22.6 ± 1.0 °C, n = 4; whereas the TEX86-derived temperatures offshore averaged 27.4 ± 0.3 °C (n = 7 and were consistent with the satellite mean annual sea surface temperature (average 26.8 ± 0.4 °C, n = 7. These results suggest that TEX86 may record the sea surface mean annual temperature in the open ocean, while it likely records winter sea surface temperature in the shallower water.

  10. Characterization of hybridization within a secondary contact region of the inshore fish, Bostrychus sinensis, in the East China Sea.

    Science.gov (United States)

    Ding, Shaoxiong; Mishra, Mrinal; Wu, Haohao; Liang, Shuang; Miyamoto, Michael M

    2018-01-01

    The northwest Pacific marginal seas are a primary center of phylogeographic and evolutionary research, because of their dynamic geographic history of falling and rising sea levels during the glaciations and interglaciations of the last one million years. Here we present new molecular and morphological data for geographic samples of the four-eyed sleeper (Bostrychus sinensis), which reinforce the evidence for secondary contact and hybridization between two phylogeographic lineages in the East China Sea. Specifically, we find that the secondary contact region is characterized by a low frequency of hybridization, where mitochondrial DNA introgression is relatively common, whereas F 1 hybrids are correspondingly scarce. Furthermore, the adult standard lengths of the two phylogeographic lineages vary geographically in a manner that is consistent with reproductive character displacement. Collectively, the molecular and morphological data document that sleeper hybridization conforms to the classic "tension zone" model, where alleles are lost via reduced hybrid viability and/or positive assortative mating but are then replenished by dispersal from south of the secondary contact region. They also indicate that the two phylogeographic lineages are at an incipient stage of the speciation process. These results and conclusions for the four-eyed sleeper are presented as a case study for future research on the vicariance, secondary contact, and hybridization of marine groups in the northwest Pacific marginal seas.

  11. Detection and temporal variation of 60Co in the digestive glands of the common octopus, Octopus vulgaris, in the East China Sea

    International Nuclear Information System (INIS)

    Morita, Takami; Otosaka, Shigeyoshi; Fujimoto, Ken; Nishiuchi, Kou; Kimoto, Katsunori; Yamada, Haruya; Kasai, Hiromi; Minakawa, Masayuki; Yoshida, Katsuhiko

    2010-01-01

    60 Co were detected in common octopus specimens collected in the East China Sea in 1996-2005. The source of 60 Co has remained unclear yet. Stable isotope analyses showed that there was no difference in stable Co concentrations between octopus samples with 60 Co and without 60 Co. This result showed that the stable Co in the digestive gland of octopus potentially did not include a trace amount of 60 Co and the source of 60 Co existed independently. Furthermore, investigations of octopus in other area and other species indicated that the origin of the source of 60 Co occurred locally in the restricted area in the East China Sea and not in the coastal area of Japan. Concentrations of 60 Co have annually decreased with shorter half-life than the physical half-life. This decrease tendency suggests that the sources of 60 Co were identical and were temporary dumped into the East China Sea as a solid waste.

  12. China Emerging

    Science.gov (United States)

    2012-03-14

    In 1992, China enacted an internal law on territorial sea and contiguous zone, which claims Chinese sovereignty over all islands that fell within a...historical components to the disputes in the South China Sea that have bearing on the issue. China , Taiwan, Vietnam, Malaysia , the Philippines...The past decade of mutual respect, cooperation, and investment by China led to amazing prosperity for all Southeast Asian states and is a blueprint

  13. The Ethanolic Extracts The Gorgonian Isis hippuris Inhibited the Induced Mammary Carcinoma Growth In C3H Mice

    Science.gov (United States)

    Trianto, Agus; Andriyas, Yogi; Ridlo, Ali; Sedjati, Sri; Susilaningsih, Neni; Murwani, Retno

    2018-02-01

    The gorgonian Isis hippuris contains secondary metabolites gorgosterol and hippuristanol which are capable of inhibiting cancer cells. However, in vivo test of the gorgonian Isis hippuris extract as the anticancer drug has not been conducted. The research to study of the effect of ethanolic extract of the gorgonian on the induced tumor growth in C3H mice. The I. hippuris was obtained from Karimunjawa water in Jepara. The extract was prepared by maceration using ethanol. A total 20, 8-10 moths old of C3H mice with an initial weight of 20-25 gram were assigned into control, Ih-1, Ih-2, and Ih-3 groups. Control, Ih-1, Ih-2, and Ih-3 groups each received 0, 0.15, 1.5, and 15 mg extract per mouse per day respectively for two weeks. Cancer cells were introduced to all groups from a donor cancer mouse by injection via left or right axilla and allowed to grow. The cancer mass was removed and processed for histological examination, and cancer growth was determined according to Elston and Ellis criteria. The result showed that histological grade of cancer mass from the control group was in grade 2 or differentiated moderately. The histological grade of cancer mass from Ih-1, Ih-2, and Ih-3 groups were in grade 1 (low grade) or similar to a normal cell. Statistical analysis by Kruskal-Wallis test showed a significant difference (pdrug.

  14. A Trend Analysis: Rising Threshold for China to Use Force in Territorial Disputes in South and East China Seas

    Science.gov (United States)

    2012-12-01

    increased from 10 percent in 2001 to 15 percent in 2006. The Chinese industry constituted 48 percent of its GDP in 2005 while the amounts were 20 percent...of 1995–96 crisis and since the strengthening relations between Tokyo and Taipei , especially during Lee Teng-hui’s tenure, China was concerned

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

    Directory of Open Access Journals (Sweden)

    Yong-Hong Zhu

    2013-09-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  17. A new species of the hermit crab genus Alainopaguroides McLaughlin, 1997 (Crustacea: Decapoda: Anomura: Paguridae) from the South China Sea.

    Science.gov (United States)

    Han, Yuan-Yuan; Komai, Tomoyuki; Sha, Zhong-Li

    2016-10-10

    A new species of the pagurid hermit crab, Alainopaguroides sinensis sp. nov., is described and illustrated on the basis of a single ovigerous female specimen collected from the South China Sea. It is immediately distinguished from other known congeneric species by the possession of a subdistal spine on the lateral margin of the basal segment of the antennular peduncle, although the most similar congener is A. andamanensis McLauglin, 2002. This is the first record of the genus from the South China Sea. An identification key to the species of the genus Alainopaguroides McLaughlin, 1997 is provided.

  18. Bottom-up and top-down controls on picoplankton in the East China Sea

    Science.gov (United States)

    Guo, C.; Liu, H.; Zheng, L.; Song, S.; Chen, B.; Huang, B.

    2013-05-01

    Dynamics of picoplankton population distribution in the East China Sea (ECS), a marginal sea in the western North Pacific Ocean, were studied during two "CHOICE-C" cruises in August 2009 (summer) and January 2010 (winter). Dilution experiments were conducted during the two cruises to investigate the growth and grazing among picophytoplantkon populations. Picoplankton accounted for an average of ~29% (2% to 88%) of community carbon biomass in the ECS on average, with lower percentages in plume region than in shelf and kuroshio regions. Averaged growth rates (μ) for Prochlorococcus (Pro), Synechococcus (Syn) and picoeukaryotes (peuk) were 0.36, 0.89, 0.90 d-1, respectively, in summer, and 0.46, 0.58, 0.56 d-1, respectively, in winter. Seawater salinity and nutrient availability exerted significant controls on picoplankton growth rate. Averaged grazing mortality (m) were 0.46, 0.63, 0.68 d-1 in summer, and 0.22, 0.32, 0.22 d-1 in winter for Pro, Syn and peuk respectively. The three populations demonstrated very different distribution patterns regionally and seasonally affected by both bottom-up and top-down controls. In summer, Pro, Syn and peuk were dominant in Kuroshio, transitional and plume regions respectively. Protist grazing consumed 84%, 78%, 73% and 45%, 47%, 57% of production for Pro, Syn and peuk in summer and winter respectively, suggesting more significant top-down controls in summer. In winter, all three populations tended to distribute in offshore regions, although the area of coverage was different (peuk > Syn > Pro). Bottom-up factors can explain as much as 91.5%, 82% and 81.2% of Pro, Syn and peuk abundance variance in winter, while only 59.1% and 43.7% for Pro and peuk in summer. Regionally, Yangtze River discharge plays a significant role in affecting the intensity of top-down control, indicated by significant and negative association between salinity and grazing mortality of all three populations and higher grazing mortality to growth rate ratio

  19. Thinning Mechanism of the South China Sea Crust: New Insight from the Deep Crustal Images

    Science.gov (United States)

    Chang, S. P.; Pubellier, M. F.; Delescluse, M.; Qiu, Y.; Liang, Y.; Chamot-Rooke, N. R. A.; Nie, X.; Wang, J.

    2017-12-01

    The passive margin in the South China Sea (SCS) has experienced a long-lived extension period from Paleocene to late Miocene, as well as an extreme stretching which implies an unusual fault system to accommodate the whole amount of extension. Previous interpretations of the fault system need to be revised to explain the amount of strain. We study a long multichannel seismic profile crossing the whole rifted margin in the southwest of SCS, using 6 km- and 8 km-long streamers. After de-multiple processing by SRME, Radon and F-K filtering, an enhanced image of the crustal geometry, especially on the deep crust, allows us to illustrate two levels of detachment at depth. The deeper detachment is around 7-8 sec TWT in the profile. The faults rooting at this detachment are characterized by large offset and are responsible for thicker synrift sediment. A few of these faults appear to reach the Moho. The geometry of the acoustic basement between these boundary faults suggests gentle tilting with a long wavelength ( 200km), and implies some internal deformation. The shallower detachment is located around 4-5 sec TWT. The faults rooting at this detachment represent smaller offset, a shorter wavelength of the basement and thinner packages of synrift sediment. Two detachments separate the crust into upper, middle and lower crust. If the lower crust shows ductile behavior, the upper and middle crust is mostly brittle and form large wavelength boudinage structure, and the internal deformation of the boudins might imply low friction detachments at shallower levels. The faults rooting to deep detachment have activated during the whole rifting period until the breakup. Within the upper and middle crust, the faults resulted in important tilting of the basement at shallow depth, and connect to the deep detachment at some places. The crustal geometry illustrates how the two detachments are important for the thinning process, and also constitute a pathway for the following magmatic

  20. Seismic multiple attenuation in the northern continent-ocean transition zone of the South China Sea

    Science.gov (United States)

    Chen, N.; Li, C. F.

    2017-12-01

    In seismic exploration, especially in marine oil and gas exploration, presence of multiple reflections lowers signal-to-noise ratio of seismic data and makes it difficult to analyze seismic velocity. In northern continent-ocean transition zone of the South China Sea (SCS), low-velocity Cenozoic strata cover sets of high-velocity carbonate strata directly, and over 1000 m thick of sediments were deposited on the igneous basement in the northwest SCS. These sedimentary boundaries generate quite strong impedance interfaces and strong internal multiples. Diffractions as a result of variation of seabed topography, coupled with the vibration, free surface multiples and refraction multiples, cause a variety of strong energy disturbances and missing of frequency component. In this study, we process four recently acquired multichannel reflection seismic profiles from the northern continent-ocean transition zone of the SCS with a new combination of demultiple techniques. There is a variety of strong multiples in the raw data, and the seabed multiple occurs between 9 to 11 seconds in two-way travel time (TWTT), and we apply Surface-related Multiple Elimination (SRME) to attenuate the free surface multiples. After SRME, we use high-resolution Radon transform (RAMUR) to attenuate deep multiples concentrating below 10 seconds in TWTT. Normal moveout correction (NMO) is necessary to flatten true reflections and turn multiples into a parabola before RAMUR, and we can attenuate the deep multiples in theτ-p domain. The seabed topography varies greatly in the continent-ocean transition zone, so the diffractions are well developed. However, SRME and RAMUR are not effective in attenuating diffractions and internal multiples. We select diffracted multiple attenuation (DIMAT) after many trials and detailed analysis. The diffractions are extracted in decomposed frequency bands. The internal multiples below 11 seconds in TWTT and high-amplitude noises are successfully suppressed while

  1. Carbonate mineral saturation states in the East China Sea: present conditions and future scenarios

    Directory of Open Access Journals (Sweden)

    W.-C. Chou

    2013-10-01

    Full Text Available To assess the impact of rising atmospheric CO2 and eutrophication on the carbonate chemistry of the East China Sea shelf waters, saturation states (Ω for two important biologically relevant carbonate minerals – calcite (Ωc and aragonite (Ωa – were calculated throughout the water column from dissolved inorganic carbon (DIC and total alkalinity (TA data collected in spring and summer of 2009. Results show that the highest Ωc (∼9.0 and Ωa (∼5.8 values were found in surface water of the Changjiang plume area in summer, whereas the lowest values (Ωc = ∼2.7 and Ωa = ∼1.7 were concurrently observed in the bottom water of the same area. This divergent behavior of saturation states in surface and bottom waters was driven by intensive biological production and strong stratification of the water column. The high rate of phytoplankton production, stimulated by the enormous nutrient discharge from the Changjiang, acts to decrease the ratio of DIC to TA, and thereby increases Ω values. In contrast, remineralization of organic matter in the bottom water acts to increase the DIC to TA ratio, and thus decreases Ω values. The projected result shows that continued increases of atmospheric CO2 under the IS92a emission scenario will decrease Ω values by 40–50% by the end of this century, but both the surface and bottom waters will remain supersaturated with respect to calcite and aragonite. Nevertheless, superimposed on such Ω decrease is the increasing eutrophication, which would mitigate or enhance the Ω decline caused by anthropogenic CO2 uptake in surface and bottom waters, respectively. Our simulation reveals that, under the combined impact of eutrophication and augmentation of atmospheric CO2, the bottom water of the Changjiang plume area will become undersaturated with respect to aragonite (Ωa = ∼0.8 by the end of this century, which would threaten the health of the benthic ecosystem.

  2. Distribution, sources and budgets of particulate phosphorus and nitrogen in the East China Sea

    Science.gov (United States)

    Yu, Yu; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning

    2012-07-01

    Suspended particles were collected from the northern East China Sea (ECS) in four spring and autumn cruises to study the sources and biogeochemical behavior of particulate inorganic and organic phosphorus and nitrogen (PIP, POP, PIN, and PON). PIP and PON were dominant forms of particulate P and N, accounting for 57.2% of TPP and 78.2% of TPN, respectively. PIP and POP concentrations decreased seaward from the estuary, and had high values near Zhoushan Islands and in the northern ECS. It was indicated that the Changjiang dilute water (CDW) and the Jiangsu coastal currents (JCC), which were rich in particulate phosphorus were the major sources of PIP and POP. PIN and PON concentrations exhibited decreasing trend from the middle shelf toward land and offshore, suggesting the dilution effect of N-depleted riverine particles on particulate nitrogen in coastal waters. The highest concentrations of PIN and PON were observed in the coast of Zhejiang and in the northern ECS, which were two productive areas in the ECS. PON and PIN were primarily of marine source and POP was also influenced by phytoplankton productivity. The concentrations, compositions and distribution of particulate nutrients varied between spring and autumn, in response to the seasonal variations of phytoplankton productivity and terrestrial input. Budget calculation demonstrated that the sediment flux of Changjiang accounted for 88% of total input flux in spring and summer, indicating that the Changjiang River was the major particle source in the ECS. Particulate P was mainly from phytoplankton and the input of the Changjiang River, while the major source of particulate N was phytoplankton. Phytoplankton production contributed 70% of TPP input flux and 95% of TPN input flux in spring and summer, while 64% of TPP input and 89% of TPN input in autumn and winter. It was shown that riverine particles were enriched in inorganic P, whereas marine particles had high organic P and N content, which suggested that

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

    Science.gov (United States)

    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

  4. The large variation in organic carbon consumption in spring in the East China Sea

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    C.-C. Chen

    2013-05-01

    Full Text Available A tremendous amount of organic carbon respired by plankton communities has been found in summer in the East China Sea (ECS, and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, respiration data has rarely been collected in other seasons. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, two cruises covering almost the entire ECS shelf were conducted in the spring of 2009 and 2010. These results showed that although the fluvial discharge rates were comparable to the high riverine flow in summer, the plankton community respiration (CR varied widely between the two springs. In 2009, the level of CR was double that of 2010, with mean (± SD values of 111.7 (±76.3 and 50.7 (±62.9 mg C m−3 d−1, respectively. The CR was positively correlated with concentrations of particulate organic carbon and/or chlorophyll a (Chl a in 2009 (all p 2 (fCO2 in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, even more riverine runoff nutrients were measured in the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, which could explain why the CR was lower in 2010. During this period, lower surface water fCO2 may have been driven mainly by physical process(es. To conclude, these results indicate that high organic carbon consumption (i.e. CR in the spring of 2009 could be attributed to high planktonic biomasses, and the lower CR rate during the cold spring of 2010 might be likely limited by low temperature in the ECS. This further suggests that the high inter-annual variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance.

  5. Spatiotemporal patterns of the macrofaunal community structure in the East China Sea, off the coast of Zhejiang, China, and the impact of the Kuroshio Branch Current

    Science.gov (United States)

    Yu, Fei; Li, Xinzheng; Ma, Lin; Dong, Dong; Kou, Qi; Sui, Jixing; Gan, Zhibin; Gong, Lin; Yang, Mei; Wang, Yueyun; Sun, Yue; Wang, Jinbao; Wang, Hongfa

    2018-01-01

    The Kuroshio Current intrudes in the bottom layer of the East China Sea continental shelf from the northeast of Taiwan via two bottom branches named the Nearshore Kuroshio Branch Current (NKBC, along the 60 m isobath) and the Offshore Kuroshio Branch Current (OKBC, along the 100 m isobath). However, knowledge on the macrofaunal responses to these bottom branches is limited. This study examined the variations in the benthic macrofaunal community in a section of the East China Sea under the influence of the NKBC. Seven sites corresponding to three regions (the west, middle and east region) were sampled using an Agassiz trawl net at a monthly rate from February to November 2015 (except in August). A total of 270 macrofaunal species were collected in this study. Cluster analysis and nMDS ordination revealed three communities: the inshore, Kuroshio and offshore communities, roughly corresponding to the west, middle and east of NKBC route. Significant differences in the species composition (one-way PERMANOVA) and diversity indices (one-way ANOVA) among the regions and communities were observed, while no statistically significant difference among the months was detected. The indicator species also varied among the communities, with Sternaspis scutata and Odontamblyopus rubicundus dominating the inshore community, Camatopsis rubida, Schizaster lacunosus and Craspidaster hesperus dominating the Kuroshio community, and Portunus argentatus, Champsodon snyderi and Coelorinchus multispinulosus dominating the offshore community. Some rare species (e.g., Neobythites sivicola) may indicate the passage of the NKBC better than the indicator species. A redundancy analysis was used to describe the relationship between the macrofaunal species and environmental variables in this study. Water depth and turbidity played important roles in the distribution of the macrofauna. S. scutata and O. rubicundus were associated with high turbidity and shallow depth, while Plesionika izumiae and P

  6. Distribution and Behaviors of Cd, Cu, and Ni in the East China Sea Surface Water off the Changjiang Estuary

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    Kuo-Tung Jiann

    2009-01-01

    Full Text Available Trace metal (Cd, Cu, and Ni dis tri bu tions and be hav iors in sur face waters of the East China Sea continental shelf were investigated during an expeditioncon ducted in June 2004. Dissolved and particulate trace metal con centrations, as well as fractions of dissolved trace metals, fraction ated based on their different chemical affinities to ion exchangers, were determined using ultra-clean techniques and graphite furnace atomic absorption spectrometry (GFAAS. Large variations of dissolved (< 0.45 mm metal concentrations in the East China Sea shelf waters were found (n = 16 and ranged between 0.036 - 0.287 nM for Cd, 0.87 - 8.66 nM for Cu, and 2.66 - 6.04 nM for Ni. Particulate metal contributions were highest near the river mouth. Dis solved Cd and Ni were pre dominantly present (98% for Cd and 86% for Ni as Chelex-labile fractions in the shelf waters.

  7. Distribution, source apportionment, and transport of PAHs in sediments from the Pearl River Delta and the northern South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X.J.; Chen, S.J.; Mai, B.X.; Sheng, G.Y.; Fu, J.M.; Zeng, E.Y. [Chinese Academy of Sciences, Ghangzhou (China)

    2008-07-15

    Polycyclic aromatic hydrocarbons (PAHs) were measured in 59 surface sediments from rivers in the Pearl River Delta and the northern continental shelf of the South China Sea. Total PAH concentrations varied from 138 to 6,793 ng/g dry weight. The sources of PAH inputs to sediments in the Pearl River Delta were qualitatively and quantitatively determined by diagnostic ratios and principal components analysis with multiple linear regression. The results showed that on average coal and wood combustion, petroleum spills, vehicle emissions, and nature sources contributed 36%, 27%, 25%, and 12% of total PAHs, respectively. Coal and biomass combustion was the main source of PAHs in sediments of the South China Sea, whereas petroleum combustion was the main source of pyrolytic PAHs in riverine and estuarine sediments of the Pearl River Delta. Perylene was formed in situ in river sediments and then transported to coastal areas along with other PAHs. The relative abundance of perylene from five-ring PAHs can be used to estimate the contribution of riverine-discharged PAHs to coastal sediments.

  8. Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

    Science.gov (United States)

    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.

  9. Enhanced 3D prestack depth imaging of broadband data from the South China Sea: a case study

    Science.gov (United States)

    Zhang, Hao; Xu, Jincheng; Li, Jinbo

    2016-08-01

    We present a case study of prestack depth imaging for data from the South China Sea using an enhanced work flow with cutting edge technologies. In the survey area, the presence of complex geologies such as carbonate pinnacles and gas pockets creates challenges for processing and imaging: the complex geometry of carbonates exhibits 3D effect for wave propagation; deriving velocity inside carbonates and gas pockets is difficult and laborious; and localised strong attenuation effect from gas pockets may lead to absorption and dispersion problems. In the course of developing the enhanced work flow to tackle these issues, the following processing steps have the most significant impact on improving the imaging quality: (1) 3D ghost wavefield attenuation, in particular to remove the ghost energy associated with complex structures; (2) 3D surface-related multiple elimination (SRME) to remove multiples, in particular multiples related to complex carbonate structures; (3) full waveform inversion (FWI) and tomography-based velocity model building, to derive a geologically plausible velocity model for imaging; (4) Q-tomography to estimate the Q model which describes the intrinsic attenuation of the subsurface media; (5) de-absorption prestack depth migration (Q-PSDM) to compensate the earth absorption and dispersion effect during imaging especially for the area below gas pockets. The case study with the data from the South China Sea shows that the enhanced work flow consisting of cutting edge technologies is effective when the complex geologies are present.

  10. Sequence architecture of the Palaeocene Transitional Facies and Response to Tectonic Evolution and Sea Level Change in the Lishui Depression, East China Sea

    Science.gov (United States)

    Li, D.

    2016-12-01

    The Lishui Depression (LD) is a polycyclic rift basin located in the southwestern of the East China Sea Shelf Basin. From bottom to top, the Palaeocene strata sequentially comprise the Yueguifeng (YGF), Lingfeng (LF) and Mingyuefeng Formations (MYF). The YGF clastic deposits were produced by a continental lacustrine. The LF and MYF were a set of coal-bearing strata formed by marine transgressive-regressive cycles. The Palaeocene depositional cycle is divided into two second-order sequences, namely SQII1 (YGF, 66.5-60Ma) and SQII2 (LF and MYF, 60-53Ma), which can be interpreted as the initial rifting sequence and the strong rifting sequence respectively that controlled by episodic tectonic subsidence, namely Yandang and Oujiang movements. The SQII1 includes only one third-order sequence, namely SQIII1, which is constituted by lake transgressive systems tract (LTST) and lake regressive systems tract (LRST). The SQII2 can be subdivided into four third-order sequences, namely SQIII2 (Lower LF, 60-57Ma), SQIII3 (Upper LF, 57-55Ma), SQIII4 (Lower MYF, 55-54.5Ma) and SQIII5 (Upper MYF, 54.5-53Ma). In the SQIII2 period, LD suffered massive transgression and the sustained high relative sea level led to the only development of transgressive systems tract (TST) and highstand systems tract (HST). In the SQIII3 period, the relative sea level declined and simultaneously two sets of incised valley were recognized on the seismic reflection with no lowstand fan developed. So the SQIII3 is considered to be composed of basin margin systems tract (BMST, similar to the shelf margin systems tract), TST and HST. Early SQIII4 (55Ma ), the relative sea level started global rapid declining and the LST of LD developed a completed system of prograding wedge, incised valley and basin floor fan. While the TST developed a retrograding marine sediments and the HST was characterized by a typical foreset parasequences. In SQIII5 period, the global sea level continuously rose and the sedimentary

  11. Numerical study of summertime dynamical and physical changes in the southern South China Sea due to the monsoons and its impacts on primary productivity

    Science.gov (United States)

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

    2016-04-01

    The ecosystem off the east coast of Peninsular Malaysia is controlled by multiple physical processes during the monsoons (winter and summer) , including the air-sea interaction (such as net heat and surface freshwater fluxes), the small-scale eddies off the southern South China Sea (SSCS), and the monsoon wind induced coastal upwelling. Using high-resolution Regional Ocean Modeling System (ROMS), in-situ observations and remote sensing data, this paper attempts to study the hydrodynamics of the shelf and coastal processes as well as thermohaline circulation in response to changes in the hydrological seasonal cycle especially in the summer monsoon. In addition, we investigate its impacts on the spatial patterns of chlorophyll biomass which acts as a proxy for primary productivity in the SSCS. This study looks into not only the detailed small-scale-circulation such as localized eddies but also the link between the southern South China Sea and the Indian Ocean through the Straits of Malacca and the Java Sea. The flow through the Strait of Malacca and the Java Sea is not only important for navigational purpose but also has an influence on the seasonal spatial and temporal variations of primary productivity in the region. Keywords: southern South China Sea; summer monsoon; coastal upwelling; primary productivity

  12. Different Responses of Sea Surface Temperature in the South China Sea to Various El Niño Events during Boreal Autumn

    Science.gov (United States)

    Wang, X.; Tan, W.; Wang, W.; Wang, C.

    2016-02-01

    This study investigates variations of sea surface temperature (SST) anomalies in the South China Sea (SCS) during developing autumn of various El Niño events. The warm SCS SST anomalies are observed in the SCS for canonical El Niño and El Niño Modoki I, whereas the cold SST anomalies are found for El Niño Modoki II. The ocean heat budget analyses show that the latent heat flux change induced by various types of El Niño is a major contributor to the SCS SST variations. An anomalous anticyclone resides near the Philippine Sea for canonical El Niño and El Niño Modoki I, which induces the southerly wind anomalies over the SCS and thus weakens the climatological northeasterly in boreal autumn. The weakened surface wind speed reduces heat loss from the ocean, leading to a warmer state in the SCS. For El Niño Modoki II, the anomalous anticyclone shifts westward to the west of the SCS, and thus the northeasterly wind anomalies appear in the SCS. Such northeasterly anomalies combined with the climatological northeasterly monsoon increase the wind speed, and make the ocean release more latent heat and thus result in the cooling SCS. The anomalous anticyclone associated with three types of El Niño can intensify the shortwave radiation. The increases of the shortwave radiation can also contribute to the SCS warming together with the latent heat flux for canonical El Niño and El Niño Modoki I. However, the magnitude of the latent heat flux is larger than that of the shortwave radiation flux for El Niño Modoki II, and thus the SCS tends to be cool.

  13. Seasonal Dynamics of Dissolved Organic Carbon Under Complex Circulation Schemes on a Large Continental Shelf: The Northern South China Sea

    Science.gov (United States)

    Meng, Feifei; Dai, Minhan; Cao, Zhimian; Wu, Kai; Zhao, Xiaozheng; Li, Xiaolin; Chen, Junhui; Gan, Jianping

    2017-12-01

    We examined the distribution and seasonality of dissolved organic carbon (DOC) based on a large data set collected from the northern South China Sea (NSCS) shelf under complex circulation schemes influenced by river plume, coastal upwelling, and downwelling. The highest surface values of ˜117 μmol L-1 were observed nearshore in summer suggesting high DOC supplies from the river inputs, whereas the lowest surface values of ˜62 μmol L-1 were on the outer shelf in winter due to entrainment of DOC-poor subsurface water under strengthened vertical mixing. While the summer coastal upwelling brought lower DOC from offshore depth to the nearshore surface, the winter coastal downwelling delivered higher surface DOC to the midshelf deep waters from the inner shelf fueled by the China Coastal Current (CCC) transporting relatively high DOC from the East China Sea to the NSCS. The intensified winter downwelling generated a cross-shelf DOC transport of 3.1 × 1012 g C over a large shelf area, which induced a significant depression of the NSCS DOC inventory in winter relative to in autumn. In addition to the variable physical controls, net biological production of DOC was semiquantified in both the river plume (2.8 ± 3.0 μmol L-1) and coastal upwelling (3.1 ± 1.3 μmol L-1) in summer. We demonstrated that the NSCS shelf had various origins of DOC including riverine inputs, inter-shelf transport and in situ production. Via cross-shelf transport, the accumulated DOC would be exported to and stored in the deep ocean, suggesting that continental shelves are a potentially effective carbon sink.

  14. High spatial variability of coral, sponges and gorgonian assemblages in a well preserved reef

    Directory of Open Access Journals (Sweden)

    Patricia González-Díaz

    2010-06-01

    Full Text Available The main goal of this research was to obtain baseline field data of the composition of sponges, corals, and gorgonian assemblages that can be used as a reference for future analyses of anthropogenic impact. We tested the hypothesis that relatively homogeneous and well preserved reef units can present notable natural variability in the composition of their communities which are unassociated with changes in land proximity or a human impact gradient. Research was carried out in July 2006 at Los Colorados reef, located in the northwestern region of Pinar del Río Province, Cuba at 12 sampling stations. The biotopes selected were crest, terrace edge and spur and grove. Ecological indicators were diversity of corals, species composition, density of corals, hydrocorals, gorgonians and sponges, and density of selected coral species. A total of 2659 colonies of scleractineans corals representing 36 species were counted. The most abundant species in the crest biotope were Millepora alcicornis, Acropora palmata and Porites astreoides; in the terrace edge and spur and grove, the most abundant species were Siderastrea siderea, Stephanocoenia intersepta, Porites astreoides, Agaricia agaricites and Montastraea cavernosa. We found differences among sites for several indicators (e.g. density of corals, sponges and gorgonians and for selected species, but they could not be associated to any gradient of land influence or human impact. Therefore, sites inside a relatively homogeneous reef unit can present notable natural differences in the composition of their communities. Rev. Biol. Trop. 58 (2: 621-634. Epub 2010 June 02.El objetivo principal de la investigación fue obtener una línea base de la composición de las comunidades de esponjas, corales y gorgonias que pueda ser utilizada como referencia para futuros análisis de impacto antrópico. Nuestra hipótesis es que un arrecife relativamente homogéneo y bien conservado, presenta una variabilidad natural

  15. Climate Change and China as a Global Emerging Regulatory Sea Power in the Arctic Ocean: Is China a Threat for Arctic Ocean Security?

    DEFF Research Database (Denmark)

    Cassotta, Sandra; Hossain, Kamrul; Ren, Jingzheng

    2015-01-01

    The impact of climate change in the Arctic Ocean such as ice melting and ice retreat facilitates natural resources extraction. Arctic fossil fuel becomes the drivers of geopolitical changes in the Arctic Ocean. Climate change facilitates natural resource extractions and increases competition...... imperialistic” resulting in substantial impact on the Arctic and Antartic dynamism. Due to ice-melting, an easy access to natural resources, China’s Arctic strategy in the Arctic Ocean has reinforced its military martitime strategy and has profoundly changed its maritime military doctrine shifting from regional...... between states and can result in tensions, even military ones. This article investigates through a political and legal analysis the role of China as an emerging regulatory sea power in the Arctic Ocean given its assertive “energy hungry country behaviour” in the Arctic Ocean. The United Nations Convention...

  16. South China, East Vietnam or West Philippine? Comparative Framing Analysis of Regional News Coverage of Southeast Asian Sea Disputes

    Directory of Open Access Journals (Sweden)

    Freeman Bradley C.

    2017-01-01

    Full Text Available For years, the world paid scant attention to the sporadic skirmishes and sovereignty squabbles in what is known by many as the South China Sea. However, in the past few years, there have been several noteworthy happenings that have drawn the attention of media outlets, including a Chinese oil rig placement near Vietnam, a Philippineinternational court case, a U.S.–ASEAN summit, and Chinese reclamation projects. Many of the countries involved are members of the regional grouping known as ASEAN (Association of Southeast Asian Nations. This study examined Asean’s English-language press, looking at the amount, patterns, and tone of coverage given to regional maritime disputes. Results indicate that use of the term ‘South China Sea’ prevails in all countries except Vietnam. The Asean newspapers have devoted a consistent and substantial amount of space to covering the topic. Indonesia’s Jakarta Post tended to use neutral or positive language when mentioning Asean and the US, while China saw more negative associations in the coverage. Further research is suggested, taking into account mass communication theories and perspectives.

  17. Revised South China Sea spreading history based on macrostructure analysis of IODP Expedition 349 core samples and geophysical data

    Science.gov (United States)

    Sun, Z.; Ding, W.; Zhao, X.; Qiu, N.; Lin, J.; Li, C.

    2017-12-01

    In Internaltional Ocean Discovery Program (IODP) Expedition 349, four sites were drilled and cored successfully in the South China Sea (SCS). Three of them are close to the central spreading ridge (Sites U1431, U1433 and U1434), and one (Site U1435) is located on an outer rise,,providingsignificant information on the spreading history of the SCS.In order to constrain the spreading historymore accurately with the core results, we analyzed the identifiable macrostructures (over 300 fractures, veins and slickensides)from all the consolidated samples of these four drill sites. Then we made a retrograde reconstruction of the SCS spreading history with the constraints of the estimated fractures and veins, post-spreading volcanism,seismic interpretation, as well as free-air gravity and magnetic anomaly and topography analysis. Our study indicates that the spreading of the SCS experienced at least one ridge jump event and two events of ridge orientation and spreading direction adjustment, which mademagnetic anomaly orientation, ridge positionand facture zone directionskeep changing in the South China Sea. During the last spreading stage, the spreading direction was north-southward but lasted for a very short time period. The oceanic crust is wider in the eastern SCS and tapers out toward west.Due to the subductionof SCS beneath the Philippine Sea plate, the seafloor began to develop new fractures:the NWW-to EW-trending R' shear faults and the NE-trending P faultsbecame dominant faults and controlled the eruption of post-drift volcanism.

  18. Comparison of Satellite-Derived Phytoplankton Size Classes Using In-Situ Measurements in the South China Sea

    Directory of Open Access Journals (Sweden)

    Shuibo Hu

    2018-03-01

    Full Text Available Ocean colour remote sensing is used as a tool to detect phytoplankton size classes (PSCs. In this study, the Medium Resolution Imaging Spectrometer (MERIS, Moderate Resolution Imaging Spectroradiometer (MODIS, and Sea-viewing Wide Field-of-view Sensor (SeaWiFS phytoplankton size classes (PSCs products were compared with in-situ High Performance Liquid Chromatography (HPLC data for the South China Sea (SCS, collected from August 2006 to September 2011. Four algorithms were evaluated to determine their ability to detect three phytoplankton size classes. Chlorophyll-a (Chl-a and absorption spectra of phytoplankton (aph(λ were also measured to help understand PSC’s algorithm performance. Results show that the three abundance-based approaches performed better than the inherent optical property (IOP-based approach in the SCS. The size detection of microplankton and picoplankton was generally better than that of nanoplankton. A three-component model was recommended to produce maps of surface PSCs in the SCS. For the IOP-based approach, satellite retrievals of inherent optical properties and the PSCs algorithm both have impacts on inversion accuracy. However, for abundance-based approaches, the selection of the PSCs algorithm seems to be more critical, owing to low uncertainty in satellite Chl-a input data

  19. Numerical Mesocosm Experimental Study on Harmful Algal Blooms of Two Algal Species in the East China Sea

    Directory of Open Access Journals (Sweden)

    Liangsheng Zhu

    2015-01-01

    Full Text Available From the results of algal culture and mesocosm experiments, a numerical mesocosm experiment is designed that accounts for the effect of the marine environment (sea currents, nutrient levels, and temperature on the harmful algal bloom (HAB processes of Skeletonema costatum and Prorocentrum donghaiense, two of the most frequent HAB-associated species in the East China Sea. Physical and ecological environment of the waters is simulated numerically by applying a hydrodynamic-ecological-one-way-coupled marine culture box model, which is semienclosed. The algal growth rate is digitalized by a temperature-factor-optimization Droop equation. A 90-mode-day numerical mesocosm experiment for the above two species is conducted. The species were found to alternately trigger algal blooms in the experimental waters, replicating the population succession phenomenon observed in the field and confirming that the two HAB species compete for nutrients. Deductively, the numerical result shows that both the Taiwan Warm Current and the eutrophication in the adjacent water of the Yangtze River Estuary contribute to the northward movement of algal concentration centers during HAB and also suggests that the lack of nutritious supplements in the open sea limits HAB occurrences in coastal waters.

  20. Hydrological and Biogeochemical Controls on Absorption and Fluorescence of Dissolved Organic Matter in the Northern South China Sea

    Science.gov (United States)

    Wang, Chao; Guo, Weidong; Li, Yan; Stubbins, Aron; Li, Yizhen; Song, Guodong; Wang, Lei; Cheng, Yuanyue

    2017-12-01

    The Kuroshio intrusion from the West Philippine Sea (WPS) and mesoscale eddies are important hydrological features in the northern South China Sea (SCS). In this study, absorption and fluorescence of dissolved organic matter (CDOM and FDOM) were determined to assess the impact of these hydrological features on DOM dynamics in the SCS. DOM in the upper 100 m of the northern SCS had higher absorption, fluorescence, and degree of humification than in the Kuroshio Current of the WPS. The results of an isopycnal mixing model showed that CDOM and humic-like FDOM inventories in the upper 100 m of the SCS were modulated by the Kuroshio intrusion. However, protein-like FDOM was influenced by in situ processes. This basic trend was modified by mesoscale eddies, three of which were encountered during the fieldwork (one warm eddy and two cold eddies). DOM optical properties inside the warm eddy resembled those of DOM in the WPS, indicating that warm eddies could derive from the Kuroshio Current through Luzon Strait. DOM at the center of cold eddies was enriched in humic-like fluorescence and had lower spectral slopes than in eddy-free waters, suggesting inputs of humic-rich DOM from upwelling and enhanced productivity inside the eddy. Excess CDOM and FDOM in northern SCS intermediate water led to export to the Pacific Ocean interior, potentially delivering refractory carbon to the deep ocean. This study demonstrated that DOM optical properties are promising tools to study active marginal sea-open ocean interactions.

  1. Examining N cycling in the northern South China Sea from N isotopic signals in nitrate and particulate phases

    Science.gov (United States)

    Yang, Jin-Yu Terence; Kao, Shuh-Ji; Dai, Minhan; Yan, Xiuli; Lin, Hui-Ling

    2017-08-01

    Nitrogen sources and dynamics, one of the key issues in marine biogeochemical cycles, remain poorly constrained in marginal seas. Here we examine the nitrogen cycle in the northern South China Sea (SCS) by combining data from previous reports with a new data set of N isotopic compositions (δ15N) of nitrate, zooplankton, and sinking particles. Average δ15N in subsurface nitrate is 4.8 ± 0.3‰, similar to that of sinking particles (δ15Nsink of 4.4‰) through the euphotic zone (EZ) collected by floating traps and to documented mean (4.6‰) for long-term mooring traps at 200 m. This along with oft-observed shallow nitracline (turnover in the ecosystem. In deep waters at 2000-3000 m, however, additional particulate N fluxes are found due to lateral transport, which contain 15N-depleted particles, resulting in a downward decreasing trend of δ15Nsink. Incorporation of lighter N by bacteria and selective export of picoplankton are proposed as alternative mechanisms contributing to low δ15Nsink in the deep waters. The significant δ15Nsink change in the deep water column makes the SCS different from most other marginal seas; thus, caution should be made when using sedimentary δ15N to reconstruct paleonitrogen processes.

  2. Highly heterogeneous bacterial communities associated with the South China Sea reef corals Porites lutea, Galaxea fascicularis and Acropora millepora.

    Directory of Open Access Journals (Sweden)

    Jie Li

    Full Text Available Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.

  3. Growth responses of Ulva prolifera to inorganic and organic nutrients: Implications for macroalgal blooms in the southern Yellow Sea, China

    Science.gov (United States)

    Li, Hongmei; Zhang, Yongyu; Han, Xiurong; Shi, Xiaoyong; Rivkin, Richard B.; Legendre, Louis

    2016-05-01

    The marine macrophyte Ulva prolifera is the dominant green-tide-forming seaweed in the southern Yellow Sea, China. Here we assessed, in the laboratory, the growth rate and nutrient uptake responses of U. prolifera to different nutrient treatments. The growth rates were enhanced in incubations with added organic and inorganic nitrogen [i.e. nitrate (NO3-), ammonium (NH4+), urea and glycine] and phosphorus [i.e. phosphate (PO43-), adenosine triphosphate (ATP) and glucose 6-phosphate (G-6-P)], relative to the control. The relative growth rates of U. prolifera were higher when enriched with dissolved organic nitrogen (urea and glycine) and phosphorus (ATP and G-6-P) than inorganic nitrogen (NO3- and NH4+) and phosphorus (PO43-). In contrast, the affinity was higher for inorganic than organic nutrients. Field data in the southern Yellow Sea showed significant inverse correlations between macroalgal biomass and dissolved organic nutrients. Our laboratory and field results indicated that organic nutrients such as urea, glycine and ATP, may contribute to the development of macroalgal blooms in the southern Yellow Sea.

  4. Cytochrome P450 diversity and induction by gorgonian allelochemicals in the marine gastropod Cyphoma gibbosum

    Directory of Open Access Journals (Sweden)

    Nelson David R

    2010-12-01

    Full Text Available Abstract Background Intense consumer pressure strongly affects the structural organization and function of marine ecosystems, while also having a profound effect on the phenotype of both predator and prey. Allelochemicals produced by prey often render their tissues unpalatable or toxic to a majority of potential consumers, yet some marine consumers have evolved resistance to host chemical defenses. A key challenge facing marine ecologists seeking to explain the vast differences in consumer tolerance of dietary allelochemicals is understanding the biochemical and molecular mechanisms underlying diet choice. The ability of marine consumers to tolerate toxin-laden prey may involve the cooperative action of biotransformation enzymes, including the inducible cytochrome P450s (CYPs, which have received little attention in marine invertebrates despite the importance of allelochemicals in their evolution. Results Here, we investigated the diversity, transcriptional response, and enzymatic activity of CYPs possibly involved in allelochemical detoxification in the generalist gastropod Cyphoma gibbosum, which feeds exclusively on chemically defended gorgonians. Twelve new genes in CYP family 4 were identified from the digestive gland of C. gibbosum. Laboratory-based feeding studies demonstrated a 2.7- to 5.1-fold induction of Cyphoma CYP4BK and CYP4BL transcripts following dietary exposure to the gorgonian Plexaura homomalla, which contains high concentrations of anti-predatory prostaglandins. Phylogenetic analysis revealed that C. gibbosum CYP4BK and CYP4BL were most closely related to vertebrate CYP4A and CYP4F, which metabolize pathophysiologically important fatty acids, including prostaglandins. Experiments involving heterologous expression of selected allelochemically-responsive C. gibbosum CYP4s indicated a possible role of one or more CYP4BL forms in eicosanoid metabolism. Sequence analysis further demonstrated that Cyphoma CYP4BK/4BL and vertebrate

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Ryofu Maru in the East China Sea, North Pacific Ocean and others from 1995-07-16 to 1999-11-05 (NODC Accession 0116981)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116981 includes Surface underway data collected from Ryofu Maru in the East China Sea (Tung Hai), North Pacific Ocean, Philippine Sea, Sea of Japan...

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Ryofu Maru in the East China Sea, North Pacific Ocean and others from 2000-01-22 to 2009-07-06 (NODC Accession 0116980)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116980 includes Surface underway data collected from Ryofu Maru in the East China Sea (Tung Hai), North Pacific Ocean, Philippine Sea, Sea of Japan...

  7. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from KEIFU MARU in the East China Sea, North Pacific Ocean and others from 2001-01-20 to 2012-06-12 (NODC Accession 0116978)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116978 includes Surface underway data collected from KEIFU MARU in the East China Sea (Tung Hai), North Pacific Ocean, Philippine Sea, Sea of Japan...

  8. A three-dimensional mixed finite-difference Galerkin function model for the oceanic circulation in the Yellow Sea and the East China Sea

    Science.gov (United States)

    Lee, Ho Jin; Jung, Kyung Tae; Foreman, M. G. G.; Chung, Jong Yul

    2000-06-01

    A three-dimensional mixed-type model which uses a finite-difference approximation in the horizontal plane and function expansions in the vertical direction is developed for the simulation of oceanic flows in the Yellow Sea (YS) and the East China Sea (ECS). The model assumes a hydrostatic balance and solves the three-dimensional, non-linear free-surface, primitive equations for homogeneous fluids. To represent the velocity structure of oceanic currents, a set of linear interpolation functions is used from the sea surface to a depth of 300 m, characterizing the thickness of the oceanic flow, and a similarity function of the exponential type underneath. The vertical eddy viscosity takes a flow-related form in which the strong mixing due to the M 2 tide is incorporated as the background eddy viscosity. A radiation condition developed by Flather (1976. Memories de la Societe Royale des Science de Liege 10, 141-164) is employed along the open boundaries. A series of numerical experiments have been carried out using linear and quadratic bottom friction formulae. The coefficient of linear bottom friction was given by Hunter's formula (1975. Estarine and Coastal Marine Science 3, 473-475), taking into account that the oceanic flows in shelf seas are of secondary importance. The quadratic bottom friction coefficient was taken as 0.0025, the same value used in previous numerical experiments of oceanic circulation in the study area (for example, Lee, 1996. Ph.D. Thesis, Kyushu University). Both results are quite similar over the outer shelf region (Okinawa Trough and the shelf break west of Kyushu) in which tidal effects on the bottom friction are relatively small, and are qualitatively in good agreement with recent observations by ARGOS buoy tracking ( Lie and Cho, 1997. The Journal of the Korean Society of Oceanography 32, 1-7; Lie et al., 1998. Journal of Geophysical Research 103, 2963-2976). A clear difference was, however, found in the distribution of sea surface

  9. Remarkable Impacts of Indian Ocean Sea Surface Temperature on Interdecadal Variability of Summer Rainfall in Southwestern China

    Directory of Open Access Journals (Sweden)

    Jingpeng Liu

    2018-03-01

    Full Text Available During the boreal summer from June to August, rainfall in Southwestern China shows substantial interdecadal variabilities on timescales longer than 10 years. Based on observational analyses and numerical modeling, we investigated the characteristics of interdecadal Southwestern China summer rainfall (SWCSR and its dynamic drivers. We find that the SWCSR is markedly impacted by the interdecadal Indian Ocean basin mode (ID-IOBM of the sea surface temperature (SST, which may induce anomalous inter-hemispheric vertical circulation. During the cold phase of the ID-IOBM, an enhanced lower-level divergence and upper-level convergence exist over the tropical Indian Ocean. The simultaneous lower-level outflow anomalies further converge over the Indo-China peninsula, resulting in an anomalous ascending motion and a lower-level cyclone that contribute to strengthening the eastward moisture transport from the Bay of Bengal to Southwestern China. The joint effects of the anomalous ascending motion and the above-normal moisture transport play a key role in increasing the SWCSR. In summers during the warm phase of the ID-IOBM, the situation is approximately the same, but with opposite polarity. After the beginning of the 1970s, the impacts of interdecadal Indian Ocean dipole (ID-IOD on SWCSR is strengthening. The anomalous vertical circulation associated with the positive (negative phase of ID-IOD is in favor of decreased (increased rainfall in SWC. However, the impacts of ID-IOD on SWCSR is relatively weak before the 1970s, indicating that the ID-IOD is the secondary driver of the interdecadal variability of SWCSR. Modeling results also indicate that the ID-IOBM of SST anomalies is the main driver of interdecadal variability of SWCSR.

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

    Science.gov (United States)

    2013-03-01

    Mahathir Mohamed (1981-2003) first visited China in 1985. Much like his pragmatic economic approach to the U.S. (another powerful country with...Senior Officials Consultation in 1995, and the ASEAN Plus Three in 1997.18 Following the 22-year tenure of Prime Minister Mahathir , who evolved from...high-value agricultural products.27 11 Much as Mahathir had looked to China in the 1990s to help pull Malaysia out of recession by increasing

  11. Impacts of Fukushima Daiichi Nuclear Power Plant accident on the Western North Pacific and the China Seas: Evaluation based on field observation of137Cs.

    Science.gov (United States)

    Wu, Junwen

    2018-02-01

    After the Fukushima nuclear accident (FNA), 137 Cs activities of seawater in the Western North Pacific (WNP) and China Seas were determined in order to examine whether 137 Cs derived from FNA across the Kuroshio was still existed and if there were any indications of FNA's impact. High 137 Cs activities at 200-500m were observed in the south of Kuroshio during 2015, indicating 137 Cs from FNA could cross the Kuroshio. Surface 137 Cs activities were on average 1.43±0.42Bqm -3 for WNP, 1.11±0.14Bqm -3 for South China Sea (SCS) and 1.10±0.29Bqm -3 for East China Sea (ECS) during 2011-2015. The activities and inventories of 137 Cs were almost identical before and after the FNA, indicating the impacts of FNA on the WNP and China Seas were minor. The effective environmental half-lives of 137 Cs in surface seawater were firstly estimated to be 14.4±1.7yrs for ECS and 16.9±2.1yrs for SCS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. An updated astronomical time scale for the Plio-Pleistocene deposits from South China Sea and new insights into Asian monsoon evolution

    NARCIS (Netherlands)

    Ao, H.; Dekkers, M.J.; Qin, L.; Xiao, G.

    2011-01-01

    Here we present an improved astronomical timescale since 5 Ma as recorded in the ODP Site 1143 in the southern South China Sea, using a recently published Asian summer monsoon record (hematite to goethite content ratio, Hm/Gt) and a parallel benthic δ18O record. Correlation of the benthic δ18O

  13. Assessment of undiscovered conventional oil and gas resources in the West Korea Bay–North Yellow Sea Basin, North Korea and China, 2017

    Science.gov (United States)

    Schenk, Christopher J.; Tennyson, Marilyn E.; Mercier, Tracey J.; Hawkins, Sarah J.; Finn, Thomas M.; Gaswirth, Stephanie B.; Marra, Kristen R.; Klett, Timothy R.; Le, Phuong A.; Leathers-Miller, Heidi M.; Woodall, Cheryl A.

    2017-07-11

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered, technically recoverable conventional resources of 1.1 billion barrels of oil and 2.2 trillion cubic feet of gas in the West Korea Bay–North Yellow Sea Basin, North Korea and China.

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

    Science.gov (United States)

    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.

  15. A review of the green tides in the Yellow Sea, China.

    Science.gov (United States)

    Liu, Xiangqing; Wang, Zongling; Zhang, Xuelei

    2016-08-01

    The recurrent green tide of Ulva prolifera caused serious ecological problems in the Yellow Sea and attached substantial scientific study. The bloom originated in the Subei Shoal area and drifted to the coast of Shandong Province during the period from May to July, driven by a series of physical processes. Here we reviewed advances in the understanding of green tides in the Yellow Sea and elucidate the developmental model of this phenomenon. This knowledge will help resource managers to take reasonable measures to mitigate the impacts to the Yellow Sea. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Characterizing the nonlinear internal wave climate in the northeastern South China Sea

    Directory of Open Access Journals (Sweden)

    S. R. Ramp

    2010-09-01

    Full Text Available Four oceanographic moorings were deployed in the South China Sea from April 2005 to June 2006 along a transect extending from the Batanes Province, Philippines in the Luzon Strait to just north of Dong-Sha Island on the Chinese continental slope. The purpose of the array was to observe and track large-amplitude nonlinear internal waves (NIWs from generation to shoaling over the course of one full year. The basin and slope moorings observed velocity, temperature (T and salinity (S at 1–3 min intervals to observe the waves without aliasing. The Luzon mooring observed velocity at 15 min and T and S at 3 min, primarily to resolve the tidal forcing in the strait.

    The observed waves travelled WNW towards 282–288 degrees with little variation. They were predominantly mode-1 waves with orbital velocities exceeding 100 cm s−1 and thermal displacements exceeding 100 m. Consistent with earlier authors, two types of waves were observed: the a-waves arrived diurnally and had a rank-ordered packet structure. The b-waves arrived in between, about an hour later each day similar to the pattern of the semi-diurnal tide. The b-waves were weaker than the a-waves, usually consisted of just one large wave, and were often absent in the deep basin, appearing as NIW only upon reaching the continental slope. The propagation speed of both types of waves was 323±31 cm s−1 in the deep basin and 222±18 cm s−1 over the continental slope. These speeds were 11–20% faster than the theoretical mode-1 wave speeds for the observed stratification, roughly consistent with the additional contribution from the nonlinear wave amplitude. The observed waves were clustered around the time of the spring tide at the presumed generation site in the Luzon Strait, and no waves were observed at neap tide. A remarkable feature was the distinct lack of waves during the winter months, December 2005 through February

  17. Structural characteristics of pre-Cenozoic erathem on continental margins of the Southwest Sub-basin, South China Sea and its geological implications

    Science.gov (United States)

    Zhu, Rongwei; Liu, Hailing; Yan, Pin; Yao, Yongjian; Zhou, Yang; Wang, Yin; Li, Yuhan

    2017-04-01

    Pre-Cenozoic structural characteristics on the conjugated continental margins, Zhongsha- Xisha block (ZSXSB) in the northwest and Nansha block (NSB) in the southeast, of the Southwest Sub-basin is fundamental to understand their tectonic contact relationship before the formation of the South China Sea. Some unpublished and published multi-channel seismic profiles 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, while the lower structural layer suffering compression is Mesozoic-Paleozoic in ZSXSB and Mesozoic in NSB, respectively. These compressional structures were formed mainly in Late Mesozoic Era. Further structural restoration was done to remove the Cenozoic tectonic influence and to calculate the pre-Cenozoic tectonic compression ratios. It is shown that tectonic compression ratios of NNW or NWW orientations gradually increase from the south to the north in the ZSXSB and southern NSB. While tectonic compression ratios of SSE orientations southward gradually decrease in the northern NSB. The variations of the compression ratios may be related to a spreading of the proto-South China Sea in late Jurassic to Early Cretaceous (then located in south of the NSB), which probably had pushed the NSB drifted northward and led to a soft collision suture between the ZSXSB and NSB. Thus the spreading of the Southwest Sub-basin may have started along suture zone pre-existed between the ZSXSB and NSB, which is tectonically weakness zone. Key words: Southwest Sub-basin of the South China Sea, conjugated continental margins, pre-Cenozoic compressive deformation structure, structural restoration, soft collision suture, proto-South China Sea Key words: Southwest Sub-basin of the South China Sea, Conjugated continental margins, Pre-Cenozoic structure, Structural

  18. Recent surface cooling in the Yellow and East China Seas and the associated North Pacific climate regime shift

    Science.gov (United States)

    Kim, Yong Sun; Jang, Chan Joo; Yeh, Sang-Wook

    2018-03-01

    The Yellow and East China Seas (YECS) are widely believed to have experienced robust, basin-scale warming over the last few decades. However, the warming reached a peak in the late 1990s, followed by a significant cooling trend. In this study, we investigated the characteristics of this low-frequency sea surface temperature (SST) variance and its dynamic relationship with large-scale climate variability through cyclostationary orthogonal function analysis for the 1982-2014 period. Both regressed surface winds on the primary mode of the YECS SST and trends in air-sea heat fluxes demonstrate that the intensification of the northerly winds in winter contribute largely to the recent cooling trend by increasing heat loss to the atmosphere. As a localized oceanic response to these winds, the upwind flow seems to bring warm waters and partially counteracts the basin-scale cooling, thus contributing to a weakening of the cooling trend along the central trough of the Yellow Sea. In the context of the large-scale climate variabilities, a strong relationship between the YECS SST variability and Pacific Decadal Oscillation (PDO) became weak considerably during the recent cooling period after the late 1990s as the PDO signals appeared to be confined within the eastern basin of the North Pacific in association with the regime shift. In addition to this decoupling of the YECS SST from the PDO, the intensifying Siberian High pressure system likely caused the enhanced northerly winds, leading to the recent cooling trend. These findings highlight relative roles of the PDO and the Siberian High in shaping the YECS SST variance through the changes in the large-scale atmospheric circulation and attendant oceanic advection.

  19. Mid-late Holocene changes in sedimentary organic matter on the inner shelf of the East China Sea

    Science.gov (United States)

    Wu, Xiuning; Xing, Lei; Zhang, Ting; Xiang, Rong

    2018-04-01

    Marginal seas are important transitional zones for the delivery of terrestrial organic matter (TOM) from land to the open sea, and they play an important role in the carbon cycle. Tracing the source of sedimentary organic matter (SOM) deposited in marginal seas is fundamental to our understanding of the dispersal, degradation, migration, and conversion of organic matter. This paper presents high-resolution records of bulk organic matter and biomarker proxies from Core T08 that was recovered from the inner shelf of the East China Sea (ECS), and aims to identify the contributions of marine and terrestrial organic matter over the past 3725 yrs. Total organic carbon (TOC) values were low (0.50%) and showed no significant change between 3725 and 1800 yr BP (Period I), and increased continuously from 0.40% to 0.86% after 1800 yr BP (Period II: 1800-750 yr BP; Period III: 750 yr BP-present). The TMBR‧ (ratio of terrestrial to marine biomarkers) and δ13CTOC (δ13C of TOC) values showed steady TOM contribution during Period I and higher TOM contribution driven by the increased Changjiang River (CR)-derived TOM under strong East Asian Summer Monsoon (EASM) and El Niño during Period II. During Period III, the increase in marine organic matter (MOM) contribution was indicated by the TMBR‧, and this was caused by enhanced marine productivity related to intensified vertical mixture that was driven by the strengthened East Asian Winter Monsoon (EAWM). δ13CTOC shows a contrary trend to the TMBR‧ during Period III, probably influenced by variations in the C3 vegetation type during this period. Spectral analysis of the TMBR‧ series for the last 1200 yrs shows cycles with periods of 119, 75-85, and 54 yrs, confirming that climate-related events influenced the variation in SOM under the modulation of solar activity and solar irradiance at the centennial scale.

  20. Comparison of buried sand ridges and regressive sand ridges on the outer shelf of the East China Sea

    Science.gov (United States)

    Wu, Ziyin; Jin, Xianglong; Zhou, Jieqiong; Zhao, Dineng; Shang, Jihong; Li, Shoujun; Cao, Zhenyi; Liang, Yuyang

    2017-06-01

    Based on multi-beam echo soundings and high-resolution single-channel seismic profiles, linear sand ridges in U14 and U2 on the East China Sea (ECS) shelf are identified and compared in detail. Linear sand ridges in U14 are buried sand ridges, which are 90 m below the seafloor. It is presumed that these buried sand ridges belong to the transgressive systems tract (TST) formed 320-200 ka ago and that their top interface is the maximal flooding surface (MFS). Linear sand ridges in U2 are regressive sand ridges. It is presumed that these buried sand ridges belong to the TST of the last glacial maximum (LGM) and that their top interface is the MFS of the LGM. Four sub-stage sand ridges of U2 are discerned from the high-resolution single-channel seismic profile and four strikes of regressive sand ridges are distinguished from the submarine topographic map based on the multi-beam echo soundings. These multi-stage and multi-strike linear sand ridges are the response of, and evidence for, the evolution of submarine topography with respect to sea-level fluctuations since the LGM. Although the difference in the age of formation between U14 and U2 is 200 ka and their sequences are 90 m apart, the general strikes of the sand ridges are similar. This indicates that the basic configuration of tidal waves on the ECS shelf has been stable for the last 200 ka. A basic evolutionary model of the strata of the ECS shelf is proposed, in which sea-level change is the controlling factor. During the sea-level change of about 100 ka, five to six strata are developed and the sand ridges develop in the TST. A similar story of the evolution of paleo-topography on the ECS shelf has been repeated during the last 300 ka.

  1. Aspergillus sydowii and Other Potential Fungal Pathogens in Gorgonian Octocorals of the Ecuadorian Pacific.

    Science.gov (United States)

    Soler-Hurtado, M Mar; Sandoval-Sierra, José Vladimir; Machordom, Annie; Diéguez-Uribeondo, Javier

    2016-01-01

    Emerging fungal diseases are threatening ecosystems and have increased in recent decades. In corals, the prevalence and consequences of these infections have also increased in frequency and severity. Coral reefs are affected by an emerging fungal disease named aspergillosis, caused by Aspergillus sydowii. This disease and its pathogen have been reported along the Caribbean and Pacific coasts of Colombia. Despite this, an important number of coral reefs worldwide have not been investigated for the presence of this pathogen. In this work, we carried out the surveillance of the main coral reef of the Ecuadorian Pacific with a focus on the two most abundant and cosmopolitan species of this ecosystem, Leptogorgia sp. and Leptogorgia obscura. We collected 59 isolates and obtained the corresponding sequences of the Internal Transcribed Spacers (ITS) of the ribosomal DNA. These were phylogenetically analyzed using MrBayes, which indicated the presence of two isolates of the coral reef pathogen A. sydowii, as well as 16 additional species that are potentially pathogenic to corals. Although the analyzed gorgonian specimens appeared healthy, the presence of these pathogens, especially of A. sydowii, alert us to the potential risk to the health and future survival of the Pacific Ecuadorian coral ecosystem under the current scenario of increasing threats and stressors to coral reefs, such as habitat alterations by humans and global climate change.

  2. Perezone, from the gorgonian Pseudopterogorgia rigida, induces oxidative stress in human leukemia cells

    Directory of Open Access Journals (Sweden)

    Paula A. Abreu

    Full Text Available Abstract Four bisabolanes 1–4, including perezone (1 and triacetyl perezone (2, were isolated through a bioassay-guided fractionation of the extract obtained from the Caribbean gorgonian coral Pseudopterogorgia rigida collected during an expedition cruise to the Bahamas. All isolated compounds showed to be cytotoxic toward panel of four human tumor cell lines, as quantified by the MTT assay after 72 h incubation. Perezone (1, the most active one, was further analyzed, showing to be cytotoxic, but not selective, in a 12-cell line panel comprising tumor and non-tumor, as well as human and murine cells. Additionally, 1 was assayed for cytotoxicity against HL-60 leukemic cells. Pre-treatment with an acute free radical scavenger (L-NAC before exposure of cells to perezone virtually eliminated the generation of intracellular ROS and lessened its severe cytotoxicity. The protective effect delivered by L-NAC evidences that the mechanism of perezone-induced cytotoxicity is partially associated to production of ROS and a consequent induction of oxidative stress.

  3. [Effect of stock abundance and environmental factors on the recruitment success of small yellow croaker in the East China Sea].

    Science.gov (United States)

    Liu, Zun-lei; Yuan, Xing-wei; Yang, Lin-lin; Yan, Li-ping; Zhang, Hui; Cheng, Jia-hua

    2015-02-01

    Multiple hypotheses are available to explain recruitment rate. Model selection methods can be used to identify the best model that supports a particular hypothesis. However, using a single model for estimating recruitment success is often inadequate for overexploited population because of high model uncertainty. In this study, stock-recruitment data of small yellow croaker in the East China Sea collected from fishery dependent and independent surveys between 1992 and 2012 were used to examine density-dependent effects on recruitment success. Model selection methods based on frequentist (AIC, maximum adjusted R2 and P-values) and Bayesian (Bayesian model averaging, BMA) methods were applied to identify the relationship between recruitment and environment conditions. Interannual variability of the East China Sea environment was indicated by sea surface temperature ( SST) , meridional wind stress (MWS), zonal wind stress (ZWS), sea surface pressure (SPP) and runoff of Changjiang River ( RCR). Mean absolute error, mean squared predictive error and continuous ranked probability score were calculated to evaluate the predictive performance of recruitment success. The results showed that models structures were not consistent based on three kinds of model selection methods, predictive variables of models were spawning abundance and MWS by AIC, spawning abundance by P-values, spawning abundance, MWS and RCR by maximum adjusted R2. The recruitment success decreased linearly with stock abundance (P success might be due to cannibalism or food competition. Meridional wind intensity showed marginally significant and positive effects on the recruitment success (P = 0.06), while runoff of Changjiang River showed a marginally negative effect (P = 0.07). Based on mean absolute error and continuous ranked probability score, predictive error associated with models obtained from BMA was the smallest amongst different approaches, while that from models selected based on the P-value of

  4. Dissolved trace metal (Cu, Cd, Co, Ni, and Ag) distribution and Cu speciation in the southern Yellow Sea and Bohai Sea, China

    Science.gov (United States)

    Li, Li; Xiaojing, Wang; Jihua, Liu; Xuefa, Shi

    2017-02-01

    Trace metals play an important role in biogeochemical cycling in ocean systems. However, because the use of trace metal clean sampling and analytical techniques has been limited in coastal China, there are few accurate trace metal data for that region. This work studied spatial distribution of selected dissolved trace metals (Ag, Cu, Co, Cd, and Ni) and Cu speciation in the southern Yellow Sea (SYS) and Bohai Sea (BS). In general, the average metal (Cu, Co, Cd, and Ni) concentrations found in the SYS were lower by a factor of two than those in BS, and they are comparable to dissolved trace metal concentrations in coastal seawater of the United States and Europe. Possible sources and sinks and physical and biological processes that influenced the distribution of these trace metals in the study region were further examined. Close relationships were found between the trace metal spatial distribution with local freshwater discharge and processes such as sediment resuspension and biological uptake. Ag, owing to its extremely low concentrations, exhibited a unique distribution pattern that magnified the influences from the physical and biological processes. Cu speciation in the water column showed that, in the study region, Cu was strongly complexed with organic ligands and concentrations of free cupric ion were in the range of 10-12.6-10-13.2 mol L-1. The distribution of Cu-complexing ligand, indicated by values of the side reaction coefficient α', was similar to the Chl a distribution, suggesting that in situ biota production may be one main source of Cu-complexing organic ligand.

  5. On the influence of sea level and monsoon climate on the southern South China Sea freshwater budget over the last 22,000 years

    Science.gov (United States)

    Steinke, Stephan; Chiu, Han-Yi; Yu, Pai-Sen; Shen, Chuan-Chou; Erlenkeuser, Helmut; Löwemark, Ludvig; Chen, Min-Te

    2006-07-01

    Changes in the local freshwater budget over the last 22,000 years have been estimated from a sediment core located in the southern South China Sea (SCS) using a combined approach of Mg/Ca and oxygen isotopes on the planktonic foraminifera Globigerinoides ruber (white) sensu stricto (s.s.). Core MD01-2390 (06°28,12N, 113°24,56E; water depth 1591 m) is located near the glacial paleo-river mouths of the Baram, Rajang and North Sunda/Molengraaff Rivers that drained the exposed Sunda Shelf. The δ18O seawater record reveals lower average values (-0.96±0.18‰) during the Last Glacial Maximum (LGM) when compared with modern values (-0.54±0.18‰). Low salinity during the LGM is interpreted to reflect a higher freshwater contribution due to a greater proximity of the core site to the mouths of the Baram, Rajang and North Sunda/Molengraaff Rivers at that time. A general deglacial increasing trend in salinity due to the progressive landward displacement of the coastline during deglacial shelf flooding is punctuated by several short-term shifts towards higher and lower salinity that are likely related to abrupt changes in the intensity of the East Asian summer monsoon. Thus, the deglacial δ18O seawater changes reflect the combined effects of sea-level-induced environmental changes on the shelf (e.g. phases of retreat and breakdown of the shelf drainage systems) and East Asian monsoon climate change. Lower salinity than at present during the Early Holocene may be attributed to an increase in summer monsoonal precipitation that is corroborated by previous marine and terrestrial studies that report a Preboreal-Early Holocene monsoon optimum in the Asian monsoon region.

  6. The 30-60-day Intraseasonal Variability of Sea Surface Temperature in the South China Sea dur1ing May-September

    Science.gov (United States)

    Mao, Jiangyu; Wang, Ming

    2018-05-01

    This study investigates the structure and propagation of intraseasonal sea surface temperature (SST) variability in the South China Sea (SCS) on the 30-60-day timescale during boreal summer (May-September). TRMM-based SST, GODAS oceanic reanalysis and ERA-Interim atmospheric reanalysis datasets from 1998 to 2013 are used to examine quantitatively the atmospheric thermodynamic and oceanic dynamic mechanisms responsible for its formation. Power spectra show that the 30-60-day SST variability is predominant, accounting for 60% of the variance of the 10-90-day variability over most of the SCS. Composite analyses demonstrate that the 30-60-day SST variability is characterized by the alternate occurrence of basin-wide positive and negative SST anomalies in the SCS, with positive (negative) SST anomalies accompanied by anomalous northeasterlies (southwesterlies). The transition and expansion of SST anomalies are driven by the monsoonal trough-ridge seesaw pattern that migrates northward from the equator to the northern SCS. Quantitative diagnosis of the composite mixed-layer heat budgets shows that, within a strong 30-60-day cycle, the atmospheric thermal forcing is indeed a dominant factor, with the mixed-layer net heat flux (MNHF) contributing around 60% of the total SST tendency, while vertical entrainment contributes more than 30%. However, the entrainment-induced SST tendency is sometimes as large as the MNHF-induced component, implying that ocean processes are sometimes as important as surface fluxes in generating the 30-60-day SST variability in the SCS.

  7. Assessment of Aerosol Optical Property and Radiative Effect for the Layer Decoupling Cases over the Northern South China Sea During the 7-SEAS Dongsha Experiment

    Science.gov (United States)

    Pani, Shantau Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-01-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (omega) approx. = 0.92 at 440nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the omega (approx. = 0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6W/sq m2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  8. Ecological risk assessment of arsenic and metals in sediments of coastal areas of northern Bohai and Yellow Seas, China.

    Science.gov (United States)

    Luo, Wei; Lu, Yonglong; Wang, Tieyu; Hu, Wenyou; Jiao, Wentao; Naile, Jonathan E; Khim, Jong Seong; Giesy, John P

    2010-01-01

    Distributions of arsenic and metals in surface sediments collected from the coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated. An ecological risk assessment of arsenic and metals in the sediments was evaluated by three approaches: the Sediment Quality Guidelines (SQGs) of the United States Environmental Protection Agency (USEPA), the degree of contamination, and two sets of SQGs indices. Sediments from the estuaries of the Wuli and Yalu Rivers contained some of the greatest concentrations of arsenic, cadmium, copper, mercury, lead, and zinc. Median concentrations of cadmium and mean concentrations of lead and zinc were greater than background concentrations determined for the areas. All sediments were considered to be heavily polluted by arsenic, but moderately polluted by chromium, lead, and cadmium. Current concentrations of arsenic and metals are unlikely to be acutely toxic, but chronic exposures would be expected to cause adverse effects on benthic invertebrates at 31.4% of the sites.

  9. No changes in contributions of echinoderms to the carbon budgets in shelf seas of China over the past five decades

    Science.gov (United States)

    Jin, Shaofei; Yan, Xiaodong; Zhang, Heng; Xiao, Ning; Zhang, Junlong; Liu, Wenliang; Xiong, Zhe

    2015-09-01

    The contribution over the past five decades of echinoderms to the regional carbon cycle of shelf sea areas in China, as well as the changes in calcium carbonate (CaCO3)/calcium carbonate carbon (CaCO3-C) standing stocks and production rates, was investigated using meta-analysis. We report results for water depths of echinoderm biomasses, and total macrobenthos biomasses showed no significant linear decline, but there was a significant decline for the biomass ratio of echinoderms to total macrobenthic biomass since the 1950s. However, there remain no convincing evidences to explain this due to a lack of environmental data. We suggest that studies on the responses of echinoderms to intense anthropogenic activities and climate change should concentrate on their roles in carbon budgets and macrobenthos community stability.

  10. The potential of wave and offshore wind energy in around the coastline of Malaysia that face the South China Sea

    International Nuclear Information System (INIS)

    Chiang, E.P.; Zainal, Z.A.; Aswatha Narayana, P.A.; Seetharamu, K.N.

    2006-01-01

    The world wide estimated wave resource is more than 2 TW. Offshore wind speeds are generally higher than wind speeds over land, hence higher available energy resource. The estimated offshore wind potential in European waters alone is in excess of 2500 TWh/annum. Offshore area also provides larger area for deploying wind energy devices. In recent year efforts to promote these two types of renewable and green energy sources have been intensify. Using the data obtained from the Malaysia Meteorological Service (MMS) analysis was conducted for the potential of wave energy and wind energy along the coastline of Malaysia facing the South China Sea. Maps of wave power potential were produced. The mean vector wind speed and direction were tabulated

  11. Aaptamine Derivatives with Antifungal and Anti-HIV-1 Activities from the South China Sea Sponge Aaptos aaptos

    Directory of Open Access Journals (Sweden)

    Hao-Bing Yu

    2014-12-01

    Full Text Available Five new alkaloids of aaptamine family, compounds (1–5 and three known derivatives (6–8, have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated by spectroscopic analyses, as well as by comparison with the literature data. Compounds 1–2 are characterized with triazapyrene lactam skeleton, whereas compounds 4–5 share an imidazole-fused aaptamine moiety. These compounds were evaluated in antifungal and anti-HIV-1 assays. Compounds 3, 7, and 8 showed antifungal activity against six fungi, with MIC values in the range of 4 to 64 μg/mL. Compounds 7–8 exhibited anti-HIV-1 activity, with inhibitory rates of 88.0% and 72.3%, respectively, at a concentration of 10 μM.

  12. Effect of Conway Medium and f/2 Medium on the growth of six genera of South China Sea marine microalgae.

    Science.gov (United States)

    Lananan, Fathurrahman; Jusoh, Ahmad; Ali, Nora'aini; Lam, Su Shiung; Endut, Azizah

    2013-08-01

    A study was performed to determine the effect of Conway and f/2 media on the growth of microalgae genera. Genera of Chlorella sp., Dunaliella sp., Isochrysis sp., Chaetoceros sp., Pavlova sp. and Tetraselmis sp. were isolated from the South China Sea. During the cultivation period, the density of cells were determined using Syringe Liquid Sampler Particle Measuring System (SLS-PMS) that also generated the population distribution curve based on the size of the cells. The population of the microalgae genera is thought to consist of mother and daughter generations since these microalgae genera reproduce by releasing small non-motile reproductive cells (autospores). It was found that the reproduction of Tetraselmis sp., Dunaliella sp. and Pavlova sp. could be sustained longer in f/2 Medium. Higher cell density was achieved by genus Dunaliella, Chlorella and Isochrysis in Conway Medium. Different genera of microalgae had a preference for different types of cultivation media. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Northern South China Sea Surface Circulation and its Variability Derived by Combining Satellite Altimetry and Surface Drifter Data

    Directory of Open Access Journals (Sweden)

    N. Peter Benny

    2015-01-01

    Full Text Available The present study analyses the mean and seasonal mesoscale surface circulation of the Northern South China Sea (NSCS and determines the influence of El Niño/SouthernNiño/Southern Oscillation (ENSO. High resolution Eulerian velocity field is derived by combining the available satellite tracked surface drifter data with satellite altimetry during 1993 - 2012. The wind driven current is computed employing the weekly ocean surface mean wind fields derived from the scatterometers on board ERS 1/2, QuikSCAT and ASCAT. The derived mean velocity field exhibits strong boundary currents and broad zonal flow across NSCS. The anomalous field is quite strong in the southern part and the Seasonal circulation clearly depicts the monsoonal forcing. Eddy Kinetic Energy (EKE distribution and its spatial and temporal structures are determined employing Empirical Orthogonal Function (EOF analysis. The ENSO influence on NSCS surface circulation has been analyzed using monthly absolute geostrophic velocity fields during 1996 - 1999.

  14. Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

    Directory of Open Access Journals (Sweden)

    Daidai Wu

    2011-01-01

    Full Text Available Several authigenic minerals were identified by XRD and SEM analyses in shallow sediments from the Southeast Hainan Basin, on the northern slope of South China Sea. These minerals include miscellaneous carbonates, sulphates, and framboidal pyrite, and this mineral assemblage indicates the existence of gas hydrates and a methane seep. The assemblage and fabric features of the minerals are similar to those identified in cold-seep sediments, which are thought to be related to microorganisms fostered by dissolved methane. Chemical composition of pore water shows that the concentrations of SO42-, Ca2+, Mg2+, and Sr2+ decrease clearly, and the ratios of Mg2+ to Ca2+ and Sr2+ to Ca2+ increase sharply with depth. These geochemical properties are similar to those where gas hydrates occur in the world. All results seem to indicate clearly the presence of gas hydrates or deep water oil (gas reservoirs underneath the seafloor.

  15. Biosorption of uranium(VI) by a mangrove endophytic fungus Fusarium sp. ZZF51 from the South China Sea

    International Nuclear Information System (INIS)

    Yang, H.B.; Tan, N.; Wu, F.J.; Liu, H.J.; Sun, M.; She, Z.G.; Lin, Y.C.

    2012-01-01

    The uranium(VI) accumulation was studied in detail by using the biomass of mangrove endophytic fungus Fusarium sp. ZZF51 from the South China Sea. The uranium(VI) biosorption process onto the tested fungus powders was optimized at pH 4.0, adsorption time 60 min, and uranium(VI) initial concentration 50 mg L -1 with 61.89% of removal efficiency. According to Fourier transform infrared spectra for the tested fungus before and after loaded with uranium(VI), the results showed that both of hydroxyl and carboxyl groups acted as the important roles in the adsorption process. In addition, the experimental data were analyzed by using parameter and kinetic models, and it was obtained that the Langmuir isotherm model and the pseudo-second-order kinetic model provided better correlation with the experimental data for adsorption of uranium(VI). (author)

  16. New isoquinolinequinone alkaloids from the South China Sea nudibranch Jorunna funebris and its possible sponge-prey Xestospongia sp.

    Science.gov (United States)

    He, Wen-Fei; Li, Yan; Feng, Mei-Tang; Gavagnin, Margherita; Mollo, Ernesto; Mao, Shui-Chun; Guo, Yue-Wei

    2014-07-01

    Two new renieramycin-type bistetrahydroisoquinolinequinone alkaloids, fennebricins A (1) and B (5), and one new isoquinolinequinone alkaloid, N-formyl-1,2-dihydrorenierol (7), were isolated from the skin of the South China Sea nudibranch Jorunna funebris and its possible sponge-prey Xestospongia sp., together with eight known metabolites, including three bistetrahydroisoquinolinequinones (2-4) and five isoquinolinequinones (8-12). Their structures were elucidated by analysis of spectroscopic data including 1D and 2D NMR and high-resolution electrospray ionization mass spectrometry (HRESIMS) and by comparison with data for related known compounds. All the metabolites except for 7 occurred simultaneously in the two animals, supporting recent ecological studies that the nudibranch J. funebris preys on the sponge of the genus Xestospongia. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. The Cyanobacteria-Dominated Sponge Dactylospongia elegans in the South China Sea: Prokaryotic Community and Metagenomic Insights

    Science.gov (United States)

    Gao, Zhao-Ming; Zhou, Guo-Wei; Huang, Hui; Wang, Yong

    2017-01-01

    The South China Sea is a special reservoir of sponges of which prokaryotic communities are less studied. Here, a new record of the sponge Dactylospongia elegans is reported near the coast of Jinqing Island in the South China Sea, and its prokaryotic community is comprehensively investigated. Sponge specimens displayed lower microbial diversity compared with surrounding seawater. At the phylum level, prokaryotic communities were consistently dominated by Proteobacteria, followed by Cyanobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Gemmatimonadetes, Thaumarchaeota, and Poribacteria. Operational taxonomic unit (OTU) analysis alternatively showed that the most abundant symbiont was the sponge-specific cyanobacterial species “Candidatus Synechococcus spongiarum,” followed by OTUs belonging to the unidentified Chloroflexi and Acidobacteria. Phylogenetic tree based on 16S-23S internal transcribed spacer regions indicated that the dominated cyanobacterial OTU represented a new clade of “Ca. Synechococcus spongiarum.” More reliable metagenomic data further revealed that poribacterial symbionts were highly abundant and only secondary to the cyanobacterial symbiont. One draft genome for each of the Cyanobacteria, Chloroflexi and Acidobacteria and three poribacterial genomes were extracted from the metagenomes. Among them, genomes affiliated with the Chloroflexi and Acidobacteria were reported for the first time in sponge symbionts. Eukaryotic-like domains were found in all the binned genomes, indicating their potential symbiotic roles with the sponge host. The high quality of the six recovered genomes of sponge symbionts from the sponge D. elegans makes it possible to understand their symbiotic roles and interactions with the sponge host as well as among one another. PMID:28790992

  18. Floating production platforms and their applications in the development of oil and gas fields in the South China Sea

    Science.gov (United States)

    Zhang, Dagang; Chen, Yongjun; Zhang, Tianyu

    2014-03-01

    This paper studies the current available options for floating production platforms in developing deepwater oil fields and the potential development models of future oil and gas exploration in the South China Sea. A detailed review of current deepwater platforms worldwide was performed through the examples of industry projects, and the pros and cons of each platform are discussed. Four types of platforms are currently used for the deepwater development: tension leg platform, Spar, semi-submersible platform, and the floating production system offloading. Among these, the TLP and Spar can be used for dry tree applications, and have gained popularity in recent years. The dry tree application enables the extension of the drilling application for fixed platforms into floating systems, and greatly reduces the cost and complexity of the subsea operation. Newly built wet tree semi-submersible production platforms for ultra deepwater are also getting their application, mainly due to the much needed payload for deepwater making the con