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Sample records for north yellow sea

  1. Illicit drugs and their metabolites in 36 rivers that drain into the Bohai Sea and north Yellow Sea, north China.

    Science.gov (United States)

    Wang, De-Gao; Zheng, Qiu-Da; Wang, Xiao-Ping; Du, Juan; Tian, Chong-Guo; Wang, Zhuang; Ge, Lin-Ke

    2016-08-01

    Illicit drugs and their metabolites have recently been recognized as an emerging group of contaminants due to their potential ecotoxicological impact in aquatic ecosystems. To date, information on the occurrence of these compounds in the aquatic environment of China remains limited. In this study, we collected surface water samples from 36 rivers in north China that discharge into the Bohai Sea and north Yellow Sea and measured the concentrations of amphetamine-like compounds, ketamines, cocainics, and opioids. The occurrence and spatial patterns of these substances show significant differences between the rivers and regions. Two designer drugs, methamphetamine (METH) and ketamine (KET), were the most abundant compounds detected in the entire set of samples (detection frequency of 92 and 69 %). The concentrations of METH and KET ranged from illicit drugs consumed in China. The high concentrations of these illicit drugs and their metabolites were found in areas that have a high population density. The riverine input of total illicit drugs into the Bohai Sea and north Yellow Sea was estimated to be in the range of 684 to 1160 kg per year.

  2. Observation and analysis of tidal and residual current in the North Yellow Sea in the spring

    Science.gov (United States)

    Miao, Qingsheng; Yang, Jinkun; Yang, Yang; Wan, Fangfang; Yu, Jia

    2018-02-01

    In order to study the current characteristics of the North Yellow Sea (NYS), 4 moored ADCPs (Acoustic Doppler Current Profilers) were deployed and Current characteristics were analyzed based on the observations. Results show that tidal current is the dominant and M2 is the main constituent. Shallow water constituents are obvious in the near-shore area, and tidal current ellipses directions have relations with topography. Residual currents in the Bohai Strait point to the Bohai Sea interior and the magnitude have a connection with terrain. Residual current in south NYS can be divided into two layers, and energy of residual current only accounts for about 13% of the total energy. Barotropic eddy kinetic energy plays a major role and the average in NYS accounts for 87%, baroclinic mean kinetic energy is larger in north NYS, in other regions barotropic mean kinetic energy take the leading position.

  3. Distribution of microbial populations and their relationship with environmental variables in the North Yellow Sea, China

    Science.gov (United States)

    Bai, Xiaoge; Wang, Min; Liang, Yantao; Zhang, Zhifeng; Wang, Fang; Jiang, Xuejiao

    2012-03-01

    In order to understand the large-scale spatial distribution characteristics of picoplankton, nanophytoplankton and virioplankton and their relationship with environmental variables in coastal and offshore waters, flow cytometry (FCM) was used to analyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea (NYS). The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer. For the surface layer, picoeukaryotes were abundant in the near-shore waters, Synechococcus was abundant in the offshore areas, and bacterial and viral abundances were high in the near-shore waters around the Liaodong peninsula. In the near-shore waters, no significant vertical variation of picophytoplankton (0.2-2μm) abundance was found. However, the nanophytoplankton abundance was higher in the upper layers (from the surface to 10 m depth) than in the bottom layer. For the offshore waters, both pico- and nanophytoplankton (2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass (NYSCWM). But, for the vertical distribution of virus and bacteria abundance, no significant variation was observed in both near-shore and offshore waters. Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses. Viruses showed a positive correlation with bacterial abundance, suggesting that the bacteriophage might be prominent for virioplankton (about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.

  4. 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.

  5. [Near ultraviolet absorption spectral properties of chromophoric dissolved organic matter in the north area of Yellow Sea].

    Science.gov (United States)

    Wang, Lin; Zhao, Dong-Zhi; Yang, Jian-Hong; Chen, Yan-Long

    2010-12-01

    Chromophoric dissolved organic matter (CDOM) near ultraviolet absorption spectra contains CDOM molecular structure, composition and other important physical and chemical information. Based on the measured data of CDOM absorption coefficient in March 2009 in the north area of Yellow Sea, the present paper analyzed near ultraviolet absorption spectral properties of CDOM. The results showed that due to the impact of near-shore terrigenous input, the composition of CDOM is quite different in the north area of Yellow Sea, and this area is a typical case II water; fitted slope with specific range of spectral band and absorption coefficient at specific band can indicate the relative size of CDOM molecular weight, correlation between spectral slope of the Sg,275-300), Sg,300-350, Sg,350-400 and Sg,250-275 and the relative size of CDOM molecular weight indicative parameter M increases in turn and the highest is up to 0.95. Correlation between a(g)(lambda) and M value increases gradually with the increase in wavelength, and the highest is up to 0.92 at 400 nm; being correlated or not between spectral slope and absorption coefficient is decided by the fitting-band wavelength range for the spectra slope and the wavelength for absorption coefficient. Correlation between Sg,275-300 and a(g)(400) is the largest, up to 0.87.

  6. 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.

  7. Influence of the Yellow Sea Warm Current on phytoplankton community in the central Yellow Sea

    Science.gov (United States)

    Liu, Xin; Chiang, Kuo-Ping; Liu, Su-Mei; Wei, Hao; Zhao, Yuan; Huang, Bang-Qin

    2015-12-01

    In early spring, a hydrological front emerges in the central Yellow Sea, resulting from the intrusion of the high temperature and salinity Yellow Sea Warm Current (YSWC). The present study, applying phytoplankton pigments and flow cytometry measurements in March of 2007 and 2009, focuses on the biogeochemical effects of the YSWC. The nutrients fronts were coincident with the hydrological front, and a positive linear relationship between nitrate and salinity was found in the frontal area. This contrast with the common situation of coastal waters where high salinity values usually correlate with poor nutrients. We suggested nutrient concentrations of the YSWC waters might have been enhanced by mixing with the local nutrient-rich waters when it invaded the Yellow Sea from the north of the Changjiang estuary. In addition, our results indicate that the relative abundance of diatoms ranged from 26% to 90%, showing a higher value in the YSCC than in YSWC waters. Similar distributions were found between diatoms and dinoflagellates, however the cyanobacteria and prasinophytes showed an opposite distribution pattern. Good correlations were found between the pigments and flow cytometry observations on the picophytoplankton groups. Prasinophytes might be the major contributor to pico-eukaryotes in the central Yellow Sea as similar distributional patterns and significant correlations between them. It seems that the front separates the YSWC from the coastal water, and different phytoplankton groups are transported in these water masses and follow their movement. These results imply that the YSWC plays important roles in the distribution of nutrients, phytoplankton biomass and also in the community structure of the central Yellow Sea.

  8. Subsurface pH and carbonate saturation state of aragonite on the Chinese side of the North Yellow Sea: seasonal variations and controls

    Science.gov (United States)

    Zhai, W.-D.; Zheng, N.; Huo, C.; Xu, Y.; Zhao, H.-D.; Li, Y.-W.; Zang, K.-P.; Wang, J.-Y.; Xu, X.-M.

    2014-02-01

    Based upon eight field surveys conducted between May 2011 and May 2012, we investigated seasonal variations in pH, carbonate saturation state of aragonite (Ωarag), and ancillary data on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were CO2-undersaturated in May and nearly in equilibrium with atmospheric CO2 in June. From July to October, the fugacity of CO2 (fCO2) of bottom water gradually increased from 438 ± 44 μatm to 630 ± 84 μatm, and pHT decreased from 8.02 ± 0.04 to 7.88 ± 0.06 due to local aerobic remineralization of primary-production-induced biogenic particles. The subsurface community respiration rates in summer and autumn were estimated to be from 0.80 to 1.08 μmol-O2 kg-1 d-1 within a relatively high salinity range of 31.63 to 32.25. From November to May in the next year, however, subsurface fCO2 gradually decreased and pH increased due to cooling and water column ventilation. The corresponding bottom water Ωarag was 1.85 ± 0.21 (May), 1.79 ± 0.24 (June), 1.75 ± 0.27 (July), 1.76 ± 0.29 (August), 1.45 ± 0.31 (October), 1.52 ± 0.25 (November), and 1.41 ± 0.12 (January). Extremely low Ωarag values (from 1.13 to 1.40) were observed mainly in subsurface waters within the high salinity range of 31.63 to 32.25, which covered a major fraction of the study area in October and November. Of the China seas, the North Yellow Sea represents one of the systems most vulnerable to the potential negative effects of ocean acidification.

  9. Subsurface low pH and carbonate saturation state of aragonite on China side of the North Yellow Sea: combined effects of global atmospheric CO2 increase, regional environmental changes, and local biogeochemical processes

    Science.gov (United States)

    Zhai, W.-D.; Zheng, N.; Huo, C.; Xu, Y.; Zhao, H.-D.; Li, Y.-W.; Zang, K.-P.; Wang, J.-Y.; Xu, X.-M.

    2013-02-01

    Based upon seven field surveys conducted between May 2011 and January 2012, we investigated pH, carbonate saturation state of aragonite (Ωarag), and ancillary parameters on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were nearly in equilibrium with air in May and June. From July to October, the fugacity of CO2 (fCO2) of bottom water gradually increased to 697 ± 103 μatm and pH decreased to 7.83 ± 0.07 due to respiration/remineralization processes of primary production induced biogenic particles. In November and January, bottom water fCO2 decreased and pH gradually returned to an air-equilibrated level due to cooling enhanced vertical mixing. The corresponding bottom water Ωarag was 1.74 ± 0.17 (May), 1.77 ± 0.26 (June), 1.70 ± 0.26 (July), 1.72 ± 0.33 (August), 1.32 ± 0.31 (October), 1.50 ± 0.28 (November), and 1.41 ± 0.12 (January). Critically low Ωarag values of 1.0 to 1.2 were mainly observed in subsurface waters in a salinity range of 31.5-32.5 psu in October and November, accounting for ~ 10% of the North Yellow Sea area. Water mass derived from the adjacent Bohai Sea had a typical water salinity of 30.5-31.5 psu, and bottom water Ωarag values ranged mostly between 1.6 and 2.4. This study showed that the carbonate system in the North Yellow Sea was substantially influenced by global atmospheric CO2 increase. The community respiration/remineralization rates in typical North Yellow Sea bottom water mass were estimated at 0.55-1.0 μmol O2 kg-1 d-1 in warm seasons, leading to seasonal drops in subsurface pH and Ωarag. Outflow of the Bohai Sea water mass counteracted the subsurface Ωarag reduction in the North Yellow Sea.

  10. Application of isostatic gravity anomaly in the Yellow Sea area

    Science.gov (United States)

    Hao, Z.; Qin, J.; Huang, W.; Wu, X.

    2017-12-01

    In order to study the deep crustal structure of the Yellow Sea area, we used the Airy-Heiskanen model to calculate the isostatic gravity anomaly of this area. Based on the Bouguer gravity anomaly and water depth data of this area, we chose the calculating parameters as standard crustal thickness 30 km, crust-mantle density difference 0.6g/cm3and grid spacing 0.1°×0.1°. This study reveals that there are six faults and four isostatic negative anomalies in the study area. The isostatic anomalies in much of Yellow Sea areas give priority to those with positive anomalies. The isostatic anomalies in North Yellow Sea are higher than South Yellow Sea with Jiashan-Xiangshui fault as the boundary. In the north of the study area, isostatic anomalies are characterized by large areas of positive anomaly. The change is relatively slow, and the trends give priority to the trend NE or NEE. In the middle of the north Yellow Sea basin, there is a local negative anomaly, arranged as a string of beads in NE to discontinuous distribution. Negative anomaly range is small, basically corresponds to the region's former Cenozoic sedimentary basin position. To the south of Jiashan-Xiangshui fault and west of Yellow Sea eastern margin fault, including most of the south Yellow Sea and Jiangsu province, the isostatic anomalies are lower. And the positive and negative anomalies are alternative distribution, and negative anomaly trap in extensive development. The trends give priority to NE, NEE, both to the NW. On the basis of the characteristics of isostatic gravity anomalies, it is concluded that the Yellow Sea belongs to continental crustal isostatic area whose isostatic anomalies is smooth and slow. ReferencesHeiskanen, W. A., F. A. V. Meinesz, and S. A. Korff (1958), The Earth and Its Gravity Field, McGraw-Hill, New York. Meng, X. J., X. H. Zhang, and J. Y. Yang (2014), Geophysical survey in eastern China seas and the characteristics of gravity and magnetic fields, Marine Geoglogy

  11. Intrusion of low-salinity water into the Yellow Sea Interior in 2012

    Science.gov (United States)

    Oh, Kyung-Hee; Lee, Joon-Ho; Lee, Seok; Pang, Ig-Chan

    2014-12-01

    Abnormally low-salinity water was detected in the surface layer of the central region of the Yellow Sea in August 2012. The presence of such low-salinity water in the Yellow Sea interior has never been reported previously. To understand the origin of this low-salinity water, oceanographic and wind data were analyzed, and the circulation of the surface layer was also examined in the Yellow and East China Seas using a numerical ocean model. The results confirmed that typhoons caused the low-salinity water. Two consecutive typhoons passed from east to west across the East China Sea, around the Changjiang Bank in early August 2012. Strong easterly and southeasterly winds created by the typhoons in the Yellow and East China Seas drove the low-salinity water to the north along the coast of China and northeastward toward the central region of the Yellow Sea, respectively. Usually, the northward drifting of Changjiang Diluted Water along the coast of China ends around the Jiangsu coast, where the drifting is blocked and is turned by the offshore Eulerian residual current. Therefore, the Changjiang Diluted Water does not intrude more into the Yellow Sea interior. However, in 2012, the low-salinity water drifted up to the Shandong Peninsula along the coast of China, and formed massive low-salinity water in the Yellow Sea interior combining with the other low-salinity water extended toward the central region of the Yellow Sea directly from the Changjiang Bank. Thus, the typhoons play a key role in the appearance of abnormally low-salinity water in the Yellow Sea interior and it means that the Yellow Sea ecosystem could be significantly influenced by the Changjiang Diluted Water.

  12. Roles of Sea Level and Climate Change in the Development of Holocene Deltaic Sequences in the Yellow Sea

    Science.gov (United States)

    Liu, J.; Milliman, J. D.

    2002-12-01

    Both post-glacial sea-level and climatic changes are preserved in the the shallow, low gradient, sediment-dominated Yellow Sea. As a result of rapid flooding during melt-water pulse (MWP) 1A, 14.3-14.1 ka BP, sea level reached the southern edge of the North Yellow Sea (NYS), and after MWP-1B (11.6-11.4 ka BP) sea level entered the Bohai Sea. The first major Yellow River-derived deltaic deposit formed in the NYS during decelerated transgression following MWP-1B and increased river discharge in response to re-intensification of the summer monsoon about 11 ka cal BP. A second subaqueous delta formed in the South Yellow Sea about 9-7 ka BP during decelerated transgression after MWP-1C flooding and in response to the southern shift of the Yellow River mouth. The modern subaqueous and subaerial deltas in the west Bahai Gulf and (to a lesser extent) along the Jiangus coast have formed during the modern sea-level highstand. These changing Holocene patterns are most clearly illustrated by a short film clip.

  13. SEASONAL DISTRIBUTION OF YELLOW-LEGGED GULL (LARUS CACHINNANS PALLAS, 1811 OF ISLANSDS OF OBITOCHNAYA BAY (NORTH-WEST AZOV SEA AREA

    Directory of Open Access Journals (Sweden)

    Dubinina U.U.

    2013-09-01

    Full Text Available Considered territorial connection of Yellow-legged gull in breeding colony on islands Obitochnaya Bay. Analysis of the basic stages of the annual life cycle of Larus cachinnans Pallas, 1811 with taking into account the seasonal characteristics of each age group of seagulls (young, immature, adult. Based on this data set direction and distance of displacement, among whom were identified intra-continental migrations, domestic migrations within the territory of Ukraine and migrations within the nesting area. Settlement species on islands Obitochnaya Bay characterized by: high degree conservatism of adult Yellow-legged gull a wide range in season after nesting migrations and variance of young birds, the exchange of individuals between neighbouring settlements and the establishment of new colonies at the expense of immature individuals.

  14. Optical measurements in the North Sea-Baltic Sea transition zone. I. On the origin of the deep water in the Kattegat

    Science.gov (United States)

    Højerslev, N. K.; Holt, N.; Aarup, T.

    1996-08-01

    In the North Sea-Baltic Sea region, several studies have shown that yellow substance can be treated as a quasi-conservative parameter that is negatively correlated with salinity. A review of more than 5000 historic and recently gathered yellow substance absorption and salinity measurements from the transition zone between the North Sea and the Baltic Sea have been analyzed for the purpose of water mass identification. Salinity-yellow substance scatter plots show that three water masses can be identified in the area: (1) North Sea water (high salinity, low yellow substance content); (2) Baltic Sea water (low salinity, intermediate-high yellow substance content); and (3) German Bight/Southern North Sea water (intermediate-high salinity, high yellow substance content). Based on the volume flow estimates used in a two-layer box-model of the Kattegat (Jørgensen, Continental Shelf Research, 12, 103-114, 1992) and conservation of yellow substance, it is argued that the long-term average composition of the bottom layer inflow to the Kattegat from the Skagerrak consists of about 90% North Sea/Atlantic water and 10% German Bight/Southern North Sea water. The German Bight content estimate is substantially lower than the ones given in earlier studies (50-67%) and implies that the Jutland Coastal Current only has a small impact on the water quality of the Kattegat.

  15. North Sea oil directory 1976

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    This edition of the North Sea Oil Directory has been revised to keep pace with the ever-changing North Sea industry. The information is grouped under the following topics: exploration and production; group licensees; Dutch and Norwegian licensees; UK Offshore Operators Association Committees; drilling contractors; offshore exploration and surveys; cement, drilling fluids, and related equipment; drilling equipment; prime mover, transmission equipment; production and process equipment; rig and platform equipment suppliers; rig builders, ship builders; rig and platform logistics; ports, supply bases; marine civil engineering; specialized equipment and services; classified index; and an alphabetical index. (MCW)

  16. Genetic differentiation in Japanese flounder in the Yellow Sea and ...

    African Journals Online (AJOL)

    The population structure of Japanese flounder (Paralichthys olivaceus) in the Yellow and East China Seas were analyzed using amplified fragment length polymorphism (AFLP) and cytochrome c oxidase subunit I (COI) gene sequencing. A total of 390 reproducible bands were generated by 10 AFLP primer combinations in ...

  17. Invisible Connections : Why Migrating Shorebirds Need the Yellow Sea

    NARCIS (Netherlands)

    van de Kam, Jan; Battley, Phil; McCaffery, Brian; Rogers, Danny; Hong, Jae-Sang; Moores, Nial; Yong-ki, Yu; Lewis, Jan; Piersma, Theunis

    2010-01-01

    Each year, invisible to the naked eye, millions of migrating shorebirds fly from Australasia towards the tidal flats of the Yellow Sea bordering China and Korea. Each flock is made up of individuals using whatever strategies they can muster to endure the flights, weather the storms and find safe

  18. Air-sea exchange studies at the North Sea

    NARCIS (Netherlands)

    Leeuw, G. de; Eijk, A.M.J. van; Kunz, G.J.; Veefkind, P.J.

    1996-01-01

    The North Sea can be considered as a local 'inner' sea in which many processes are quite different from these over the open ocean. The surrounding land has a major influence, being the source for man-made aerosols and gases, whereas the North Sea acts as a sink for these. At the same time the North

  19. 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.

  20. A heavy sea fog event over the Yellow Sea in March 2005: Analysis and numerical modeling

    Science.gov (United States)

    Gao, Shanhong; Lin, Hang; Shen, Biao; Fu, Gang

    2007-02-01

    In this paper, a heavy sea fog episode that occurred over the Yellow Sea on 9 March 2005 is investigated. The sea fog patch, with a spatial scale of several hundred kilometers at its mature stage, reduced visibility along the Shandong Peninsula coast to 100 m or much less at some sites. Satellite images, surface observations and soundings at islands and coasts, and analyses from the Japan Meteorology Agency (JMA) are used to describe and analyze this event. The analysis indicates that this sea fog can be categorized as advection cooling fog. The main features of this sea fog including fog area and its movement are reasonably reproduced by the Fifth-generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5). Model results suggest that the formation and evolution of this event can be outlined as: (1) southerly warm/moist advection of low-level air resulted in a strong sea-surface-based inversion with a thickness of about 600 m; (2) when the inversion moved from the warmer East Sea to the colder Yellow Sea, a thermal internal boundary layer (TIBL) gradually formed at the base of the inversion while the sea fog grew in response to cooling and moistening by turbulence mixing; (3) the sea fog developed as the TIBL moved northward and (4) strong northerly cold and dry wind destroyed the TIBL and dissipated the sea fog. The principal findings of this study are that sea fog forms in response to relatively persistent southerly warm/moist wind and a cold sea surface, and that turbulence mixing by wind shear is the primary mechanism for the cooling and moistening the marine layer. In addition, the study of sensitivity experiments indicates that deterministic numerical modeling offers a promising approach to the prediction of sea fog over the Yellow Sea but it may be more efficient to consider ensemble numerical modeling because of the extreme sensitivity to model input.

  1. Distribution and pollution assessment of heavy metals in surface sediments in the Yellow Sea.

    Science.gov (United States)

    Jiang, Xin; Teng, Ankang; Xu, Wenzhe; Liu, Xiaoshou

    2014-06-15

    Heavy metal concentrations in surface sediments at 56 stations during two cruises in the Yellow Sea in summer and winter, 2011 were analyzed by inductively coupled plasma-mass spectrometry. The pollution status was assessed via the Geoaccumulation index and Hankanson potential ecological risk index. Higher concentrations of heavy metals (except for Mn) were found in the central Southern Yellow Sea and the western Northern Yellow Sea. The higher contents of Mn were much closer to Shandong Peninsula. Correlation analyses indicated that Pb, Cu, Fe, Ni, Zn and Co probably had the same origin and were controlled by grain size and total organic carbon. Pollution assessment showed that most areas of the Yellow Sea were not or lowly contaminated with the exception of the northwest and south parts of the Southern Yellow Sea showing Cd-contamination. The pollution status of the Yellow Sea in summer was worse than that in winter. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The North Sea contracting industry

    International Nuclear Information System (INIS)

    Wright, P.J.C.

    1996-09-01

    The North Sea Contracting Industry provides in-depth profiles of major contracting organisations including manpower, facilities, expertise, future directions and financial details. It addresses key issues such as: how will the role of operators and contractors change toward 2000 and beyond?; how will the contractor-operator relationship develop?; will the contractors take a more speculative role in projects such as leasing and contract to produce?; does the future belong to broad skilled providers or small specialised niche players, or both?; and how will rapid technological improvements affect the industry? (author)

  3. Source apportionment of particulate pollutants in the atmosphere over the Northern Yellow Sea

    Science.gov (United States)

    Wang, L.; Qi, J. H.; Shi, J. H.; Chen, X. J.; Gao, H. W.

    2013-05-01

    Atmospheric aerosol samples were collected over the Northern Yellow Sea of China during the years of 2006 and 2007, in which the Total Carbon (TC), Cu, Pb, Cd, V, Zn, Fe, Al, Na+, Ca2+, Mg2+, NH4+, NO3-, SO42-, Cl-, and K+ were measured. The principle components analysis (PCA) and positive matrix factorization (PMF) receptor models were used to identify the sources of particulate matter. The results indicated that seven factors contributed to the atmospheric particles over the Northern Yellow Sea, i.e., two secondary aerosols (sulfate and nitrate), soil dust, biomass burning, oil combustion, sea salt, and metal smelting. When the whole database was considered, secondary aerosol formation contributed the most to the atmospheric particle content, followed by soil dust. Secondary aerosols and soil dust consisted of 65.65% of the total mass of particulate matter. The results also suggested that the aerosols over the North Yellow Sea were heavily influenced by ship emission over the local sea area and by continental agricultural activities in the northern China, indicating by high loading of V in oil combustion and high loading of K+ in biomass burning. However, the contribution of each factor varied greatly over the different seasons. In spring and autumn, soil dust and biomass burning were the dominant factors. In summer, heavy oil combustion contributed the most among these factors. In winter, secondary aerosols were major sources. Backward trajectories analysis indicated the 66% of air mass in summer was from the ocean, while the air mass is mainly from the continent in other seasons.

  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. The carbon budget of the North Sea

    NARCIS (Netherlands)

    Thomas, H.; Bozec, Y.; Baar, H.J.W. de; Elkalay, K.; Frankignoulle, M.; Schiettecatte, L.-S.; Kattner, G.; Borges, A.V.; Gattuso, J.-P.

    2005-01-01

    A carbon budget has been established for the North Sea, a shelf sea on the NW European continental shelf. The carbon exchange fluxes with the North Atlantic Ocean dominate the gross carbon budget. The net carbon budget – more relevant to the issue of the contribution of the coastal ocean to the

  6. Biodiversity of free-living marine nematodes in the southern Yellow Sea, China

    Science.gov (United States)

    Liu, Xiaoshou; Xu, Man; Hua, Er; Zhang, Zhinan

    2016-02-01

    Biodiversity patterns of free-living marine nematodes were studied using specific, taxonomic and phylogenetic diversity measures in the southern Yellow Sea, China. The results showed that the average of Shannon-Wiener diversity index ( H') in the study area was 3.17. The higher values were distributed in the east part of Shandong coastal waters and north part of Jiangsu coastal waters, while the lower values were distributed in the southern Yellow Sea Cold Water Mass (YSCWM). The average of taxonomic diversity ( Δ) was 62.09 in the study region. The higher values were distributed in the transitional areas between the coastal areas and the southern YSCWM, while the lower values were distributed near the north part of Jiangsu coastal waters and the YSCWM. Results of correlation analysis of species diversity and taxonomic diversity showed that some of the two kinds of diversity index were independent, which suggested that combining the two kinds of diversity indices can reflect the ecological characteristics better. A test for 95% probability funnels of average taxonomic distinctness and variation in taxonomic distinctness suggested that Station 8794 (in the YSCWM) was outside of the 95% probability funnels, which may be due to the environmental stress. Results of correlation analysis between marine nematodes biodiversity and environmental variables showed that the sediment characteristics (Mdø and Silt-clay fraction) and phaeophorbide a (Pha- a) were the most important factors to determine the biodiversity patterns of marine nematodes.

  7. The North Sea Bird Club

    International Nuclear Information System (INIS)

    Doyle, P.A.T.; Gorman, M.L.; Patterson, I.J.; Howe, S.

    1991-01-01

    This paper reports that the creation of a club for the purpose of encouraging oil and gas workers to watch birds may not at first seem a viable proposition. To the layperson, birds offshore conjures up an image of hundreds of seagulls following fishing boats, and very little else. Also, the act of birdwatching is not seen as a typical offshore worker's activity. Anyone who has worked on an installation offshore and who has any interest in wildlife will be aware of the occasional presence of land-birds. Two decades ago, prompted by some keen offshore workers, a single oil company set up a monitoring program, which quickly became popular with a number of its employees. Birds seem offshore were recorded on data forms and collected together. At this stage the club was purely another recreation facility; however, when the data were collated it was soon realized that installations offshore were being used as staging posts by birds on migration, and that the information being collected would be of great interest in the study of bird movements. All over Britain, at strategic points on the coastline, there are bird observatories which record the arrival and departure of migrating birds. The presence of several hundred solid structures up and down the North Sea, which are used by birds en route, represents a huge, unique bird observatory, capable of uncovering facts about bird migration which have long eluded land-based scientists. Eleven years ago, the North Sea Bird Club began, composed of eight member companies, a recorder from Aberdeen University and a representative from the Nature Conservancy Council. The club received data from 41 installations, and the recorder collated these on Aberdeen University's computer and produced an annual report of sightings

  8. 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

  9. Wave processes and geologic responses on the floor of the Yellow Sea

    Science.gov (United States)

    Booth, James S.; Winters, William J.

    1991-01-01

    The floor of the Yellow Sea is a geologically mundane surface: it is nearly horizontal, lacks relief, and, with few exceptions, is devoid of conspicuous geomorphologic features. However, it is the principal repository for the prodigious sediment load of the Huanghe (Yellow River); and, due to its inherent shallowness (average depth is 40 m), it is frequently stressed by waves generated by winter storms and typhoons. Analyses of mass physical properties of cores representing the upper few meters of sediment in the central and north-central Yellow Sea (near the Shandong Peninsula), in conjunction with analyses of slope stability, failure modes, and erodibility, permit an assessment of the likelihood and effect of dynamic, transient geologic events on the seabed.Vane shear-strength profiles along with consolidation test data indicate that the present surface of the seabed is in a depositional mode and is compacting normally. in addition, liquid-limit profiles imply that in the study area these neritic sediments have been accumulating in an environment that probably has not been modified significantly since sea level reached its current level. There is no geotechnical evidence in the nine cores recovered that slope failures have occurred, and clasts, sand lenses or other manifestations of mass movements, including flows, also are absent. These observations support previous interpretations of seismic records. Moreover, slope stability analysis for static conditions shows that the sea floor is quite stable.Regardless, shear-stress levels generated by cyclic loading during major storms may approach the sediment shear strengths, and, when coupled with concomitant excess pore pressures, could cause slope failure. Unless the failed beds collapsed or flowed, however, there probably would be little conspicuous evidence of such a failure. in fact, evaluation of the potential of these sediments for disintegrative behavior suggests that they are not prone to either collapse or

  10. Definition of water exchange zone between the Bohai Sea and Yellow Sea and the effect of winter gale on it

    Institute of Scientific and Technical Information of China (English)

    SONG Jun; GUO Junru; LI Jing; MU Lin; LIU Yulong; WANG Guosong; LI Yan; LI Huan

    2017-01-01

    The marine dynamic environment of the Bohai Sea and the Yellow Sea in the winter of 2006 is simulated by the Regional Ocean Modelling System (ROMS) marine numerical model. Using the simulated temperature and salinity, the water exchange zone between the Bohai Sea and Yellow Sea is defined through the Spectral Mixture Model (SMM). The influence of winter gales on the water exchange is also discussed. It is found that the Yellow Sea water masses in winter are distributed in a “tongue” shape in the Bohai Strait region, the water exchange zone presents a zonal distribution along the margin of the “tongue”, with a tendency of running from northwest to southeast, and the water exchange is intensified at the tip of the “tongue”. Besides, the coastal area in the northernmost Yellow Sea does not participate in the water exchange between the Bohai Sea and Yellow Sea. The result shows that the winter gale events play a role in enhancing the water exchange. It is specifically shown by the facts: the Yellow Sea warm current is enhanced to intrude the Bohai Sea by the gale process; the water exchange zone extends into the Bohai Sea; the water exchange belt in the southern part becomes wider; the mixture zone of river runoff with the Bohai Sea water upon its entry is enlarged and shifts northwards. Within two days after the gale process, the exchange zone retreats toward the Yellow Sea and the exchange zone resulted from the Huanghe River (Yellow River) runoff also shrinks back shoreward.

  11. Grazing and metabolism of Euphausia pacifica in the Yellow Sea.

    Directory of Open Access Journals (Sweden)

    Zhencheng Tao

    Full Text Available Grazing and metabolism of Euphausia pacifica in the Yellow Sea were studied from September 2006 to August 2007. Euphausia pacifica is a selective-feeding omnivore and grazing rates among different months were monitored using a Coulter Counter and batch culture feeding experiments. Euphausia pacifica mainly grazed microzooplankton in August and September, which resulted in an increase in chlorophyll a concentration. Oxygen consumption rate of E. pacifica was 38.7-42.5 μmol O2 g(-1 DW h(-1 in March, which was four times higher than the oxygen consumption rates in September and December. The vigorous metabolism of E. pacifica in March consumed 3.1% of body carbon daily, which is likely related to its high reproduction and grazing rate. Respiration and metabolism of E. pacifica in September and December were similar and were lower. O:N ratio of E. pacifica was the highest (17.3-23.8 in March when spawning activity occurred and when food was abundant. The energetic source of E. pacifica during September and December was mostly protein from eating a carnivorous diet, including such items as microzooplankton. Euphausia pacifica was found in cold water at the bottom of the Yellow Sea in summer and autumn and maintained a low consumption status. O:N ratios of E. pacifica in March, September, and December were negatively correlated with SSTs and no significant correlation was found between O:N ratios and chlorophyll a concentration. Seawater temperature is clearly the most important parameter influencing the metabolism of E. pacifica.

  12. The pollution of the North Sea

    International Nuclear Information System (INIS)

    1981-01-01

    The subject is covered in chapters entitled: the North Sea and its rivers; the uses of the North Sea (shipping; exploitation of oil and gas; fishing; recreation; land reclamation; industrial islands; waste dumping); the nature of the dumping problem (nuclear waste; organic chemicals; inorganic chemicals; oil; sewage; rubble and dredged spoils; ash); pollution legislation; Greenpeace activities in the North Sea (the nuclear campaigns (Windscale; Cap de la Hague; Atlantic waste dumping); the chemical campaigns); what is needed in the future; references; the Oslo Convention. (U.K.)

  13. 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.

  14. SeaWiFS: North Pacific Storm

    Science.gov (United States)

    2002-01-01

    An extratropical storm can be seen swirling over the North Pacific just south of Alaska. This SeaWiFS image was collected yesterday at 23:20 GMT. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  15. Yellow-cedar decline in the North Coast Forest District of British Columbia.

    Science.gov (United States)

    Paul E. Hennon; David V. D' Amore; Stefan Zeglan; Mike. Grainger

    2005-01-01

    The distribution of a forest decline of yellow-cedar (Callitropsis nootkatensis (D. Don) Örsted) has been documented in southeast Alaska, but its occurrence in British Columbia was previously unknown. We conducted an aerial survey in the Prince Rupert area in September 2004 to determine if yellow-cedar forests in the North Coast Forest District of...

  16. Benthic community structures in the North Sea

    Science.gov (United States)

    Heip, C.; Craeymeersch, J. A.

    1995-03-01

    Coherent assemblages of marine benthic species have been recognized from the early twentieth century, and the classical papers of Petersen (1914, 1918) were based on studies of limited areas in the North Sea. In 1986, a synoptic survey of the North Sea north to 57°N was undertaken by a group of ten laboratories from seven North Sea countries. The results of this survey have recently been published (Heip et al., 1992a, b; Künitzer et al., 1992; Huys et al., 1992), and some of the results are summarized in this paper. The analysis of the macrofauna is based on slightly more than 700 taxa. In general, the North Sea macrofauna consists of northern species extending south to the northern margins of the Dogger Bank, and southern species extending north to the 100 m depth line. The central North Sea is an area of overlap of southern and northern species, especially around the 70 m depth contour. Consistent groupings of species are recognized that were summarized in seven faunal groupings. Macrofaunal body weight, density and diversity increase linearly towards the north. Macrofaunal biomass for the whole area averages 7 g adwt. m-2 and decreases from south to north. Distribution patterns and trends within the meiofauna were very different. Nematodes, which are the dominant taxon overall, are least abundant in the sandy sediments of the Southern Bight, then increase to a maximum around 53° 30' N and slowly decrease again towards the north. Copepod density and diversity are highest in the Southern Bight, due to the presence of many interstitial species. A large number of species new to science were recorded by the North Sea Benthos Survey and about 1500 species are expected to occur. Copepods show very distinct assemblages according to water depth and sediment type. The contrasting patterns in latitudinal gradients of body weight and number of species of macro- and meiofauna can be only partially explained. Latitude and sediment characteristics, such as grain size and

  17. Neoplasia of captive yellow sea horses (Hippocampus kuda) and weedy sea dragons (Phyllopteryx taeniolatus).

    Science.gov (United States)

    LePage, Véronique; Dutton, Christopher J; Kummrow, Maya; McLelland, David J; Young, Karrie; Lumsden, John S

    2012-03-01

    Syngnathidae is the family of fish that includes sea horses, pipefish, and sea dragons. To date, only a single publication has described neoplasia in syngnathids, a fibrosarcoma of the brood pouch in an aquarium-reared lined sea horse (Hippocampus erectus). From 1998 until 2010, the Toronto Zoo submitted 172 syngnathids for postmortem; species included the spotted or yellow sea horse (Hippocampus kuda), the pot-bellied sea horse (Hippocampus abdominalis) and the weedy sea dragon (Phyllopteryx taeniolatus). Seven neoplasms and two neoplastic-like lesions were identified from these cases. Under light microscopy, the neoplasms had morphological characteristics of a cardiac rhabdomyosarcoma, renal adenocarcinoma, renal adenoma, renal round cell tumors, which were likely lymphomas, exocrine pancreatic carcinoma, and intestinal carcinoma. Of these neoplasms, four had clear evidence of metastasis: the pancreatic and intestinal carcinomas and both round cell tumors. As syngnathids are highly fastidious animals, they can be difficult to maintain in captivity. In order to improve their husbandry, preventative and palliative care, as well as treatment, it is important to investigate and document the types of diseases affecting syngnathids.

  18. Impact of tropical cyclone Matmo on mixed zone of the Yellow and Bohai seas

    Science.gov (United States)

    Guo, Jie; Ji, Diansheng; Hou, Chawei; Guo, Kai; Ji, Ling

    2017-12-01

    The Bohai Sea is a low-lying semi-enclosed sea area that is linked to the Yellow Sea via the Bohai straits (mixed zone). Its off shore seabed is shallow, which makes it vulnerable to serious marine meteorological disasters associated with the northward passage of Pacifi c tropical cyclones. Analyses on data of remote sensing and buoy of the mixed zone of the Yellow and Bohai seas indicate that all the wind speed, signifi cant wave height, and salinity (SAL) increased, sea surface temperature decreased, and wind energy density changed considerably during the passage of tropical cyclone Matmo on July 25, 2014. It was found that the SAL inversion layer in the mixed zone of the Yellow and Bohai Seas was caused by the tropical cyclone. Furthermore, it was found that the tropical cyclone transported the northern Yellow Sea cold water mass (NYSCWM) into the mixed zone of the Yellow and Bohai Seas. The NYSCWM has direct infl uence on both the aquaculture and the ecological environment of the region. Therefore, further research is needed to establish the mechanism behind the formation of the SAL inversion layer in the mixed zone, and to determine the infl uence of tropical cyclones on the NYSCWM.

  19. 'Yellow lens' eyes of a stomiatoid deep-sea fish, Malacosteus niger.

    Science.gov (United States)

    Somiya, H

    1982-07-22

    Bright yellow lenses were found in the eyes of the stomiatoid deep-sea fish, Malacosteus niger Ayres. The optical properties of the yellow lens and the retinal specializations in the eyes were examined. Absorption spectra of the yellow lens revealed two peaks at wavelengths 425 and 460 nm. The photoreceptors were all rods and were arranged in two superimposed layers. An astaxanthin-type retinal tapetum was observed in the pigment epithelium. Some chemical evidence is presented showing that the tapetal material is an astaxanthin ester. The ecological significance of the yellow lens is discussed in connection with that of Malacosteus' orbital light organ which has a reddish filter.

  20. Geology of the North Sea and Skagerrak

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, O. [ed.

    1995-12-31

    The Marine Geology Unit of the Department of Earth Sciences organized the second Marine Geology symposium at Aarhus University, 7-8 October 1993. The intention was to bring together people working especially with the geology of the North Sea and Skagerrak. Approximately 60 people from different Danish and Norwegian institutions attended the symposium. 28 oral presentations were given and 2 posters presented. A large range of geological topics was covered, embracing biostratigraphy, sequence stratigraphy, sedimentology and structural geology. The majority of the presentations dealt with Quaternary geology and Cenozoic sequence stratigraphy, but also Jurassic and Lower Cretaceous stratigraphy was treated. Studies from the major part of the Danish sector were presented, spanning from Bornholm to the central North Sea, and further into the Norwegian North Sea sector. (au)

  1. Wind fluctuations over the North Sea

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Pinson, Pierre; Giebel, Gregor

    2011-01-01

    Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms. The Hil......Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms...

  2. Tender moments in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Fox, C

    1991-04-01

    Described is tender-assisted drilling (TAD) on the UK North Sea Gannet field. The Gannet field is developed by Shell UK Exploration and Production (Shell Expro). In March 1990, Shell Expro awarded Sedco Forex the design and engineering contract to convert the semisubmersible drilling rig Sedco 704 into the Gannet TSV (Tender Support Vessel). The only semisubmersible TSV operation so far to have completed drilling in the North Sea has been in the Norwegian sector. The Odin field, operated by Esso Norge a/s, was developed using the converted drilling rig Treasure Hunter. 1 fig., 1 ill., 3 refs.

  3. 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.

  4. Distribution and air-sea exchange of mercury (Hg in the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Z. J. Ci

    2011-03-01

    Full Text Available The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0 in the atmosphere, total Hg (THg, reactive Hg (RHg and dissolved gaseous mercury (DGM, largely Hg(0 in the waters were measured aboard the R/V Kexue III. The mean (±SD concentration of GEM over the entire cruise was 2.61 ± 0.50 ng m−3 (range: 1.68 to 4.34 ng m−3, which were generally higher than other open oceans. The spatial distribution of GEM generally reflected a clear gradient with high levels near the coast of East China and low levels in open waters, suggesting the significant atmospheric Hg outflow from East China. The mean concentration of THg in the surface waters was 1.69 ± 0.35 ng l−1 and the RHg accounted for a considerable fraction of THg (RHg: 1.08 ± 0.28 ng l−1, %RHg/THg = 63.9%. The mean concentration of DGM in the surface waters was 63.9 ± 13.7 pg l−1 and always suggested the supersaturation of Hg(0 in the surface waters with respect to Hg(0 in the atmosphere (the degree of saturation: 7.8 ± 2.3 with a range of 3.6–14.0. The mean Hg(0 flux at the air-sea interface was estimated to be 18.3 ± 11.8 ng m−2 h−1 based on a two-layer exchange model. The high wind speed and DGM levels induced the extremely high Hg(0 emission rates. Measurements at three stations showed no clear vertical patterns of DGM, RHg and THg in the water column. Overall, the elevated Hg levels in the Yellow Sea compared with other open oceans suggested that the human activity has influenced the oceanic Hg cycle downwind of East Asia.

  5. Opportunities for suppliers in the North Sea

    International Nuclear Information System (INIS)

    D'Ancona, J.E.

    1992-01-01

    If European suppliers to the offshore industry are to prosper, it has to be on the basis of a single internationally competitive North Sea market. If we continue to talk and think in terms of a British sector, a Norwegian sector, Dutch and Danish sectors, then we will inhibit the full development of contractors and suppliers. The long term future in oilfield supplies lies in a mixed portfolio of international projects. Oil and gas exploration and development, particularly offshore, is notoriously cyclical. To survive the downturns in one market supply, companies need to have access to the upswing in others. The significance of a single North Sea market is that it presents an international arena for the best companies to demonstrate their technical and commercial abilities. Individual national sectors do not - cannot - provide that opportunity to anything like the same extent. Taking then the North Sea as a single competitive market, it represents the most important offshore area in the world at the present time, and this is likely to continue during the 1990s. The prospects of achieving a single North Sea market are discussed. (author)

  6. Draft Memorandum for the North Sea

    International Nuclear Information System (INIS)

    2008-12-01

    In the National Water Plan it is described which measures must be taken to keep the Netherlands safe and livable for future generations and to make use of the chances offered by water. This memorandum serves as a document by means of which political choices for the North Sea policy, as formulated in the National Water Plan, are made more transparent [nl

  7. Elastic behaviour of North Sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.

    2007-01-01

    -consistent approximation, which here represents the unrelaxed scenario where the pore spaces of the rock are assumed to be isolated, and the Gassmann theory, which assumes that pore spaces are connected, as tools for predicting the effect of hydrocarbons from the elastic properties of brine-saturated North Sea reservoir...

  8. Winter Counter-Wind Transport in the Inner Southwestern Yellow Sea

    Science.gov (United States)

    Wu, Hui; Gu, Jinghua; Zhu, Ping

    2018-01-01

    Coastal currents generally flow downshelf with land on the right side (Northern Hemisphere) under the geostrophic balance, and are often strengthened by downwelling-favorable winds. However, the recent mooring observation in the inner southwestern Yellow Sea showed that coastal transport direction can be substantially changed by tidal forcing. In the survey, the tidal-averaged transports at two out of three sites remained northward (i.e., in the upshelf direction) and opposite the downwelling-favorable northerly wind, except during a brief neap tide period. Numerical experiments showed that the incoming Poincaré wave tide from the East China Sea plays a key role in forming this counter-wind transport system. This tidal wave produces a shoreward tidal stress south of 33.5°N in the inner southwestern Yellow Sea, driving an upshelf transport under the Earth's rotation. Counterpropagating tidal waves from the East China Sea and the northern Yellow Sea collide in coastal water in 32.5-34°N, which produce a standing tidal wave and therefore a mean sea-surface setup with alongshore and cross-shelf scales of both >100 km. This sea-surface setup causes an alongshore sea surface gradient, which veers the upshelf transport to the offshore direction under geostrophic balance. The strong tidal current increases the tidal-mean bottom resistance in the SCW, thus reduces the wind-driven current to a magnitude smaller than the tide-induced residual transport velocity. Therefore, upshelf transport persists in the inner southwestern Yellow Sea, and the Changjiang River Estuary becomes a major source area for the inner southwestern Yellow Sea.

  9. How attractive is the North Sea to the financial community?

    International Nuclear Information System (INIS)

    Arnott, R.

    1992-01-01

    How attractive is the North Sea to the financial community? This question is answered by discussing the type of investment opportunity that the North Sea offers the investor. It is shown how North Sea investments have performed and some of the methods used to measure that performance are discussed. Finally, some thoughts on the future importance of the North Sea to the financial community reach the conclusion that it will remain important for some years to come. (author)

  10. The North Sea field development guide. V.1: Northern North Sea. V.2: Southern North Sea. 6. ed.

    International Nuclear Information System (INIS)

    Anon.

    1996-08-01

    The 1997/8, sixth edition is the first to be divided into two volumes. Volume 1 covers the central and northern North Sea areas; volume 2 contains the southern North Sea as well as the Irish and German sectors. The pages are numbered consecutively over the two volumes, with page numbers greater than 702 contained in the second volume. There are three index sections. Main index. Arranged by national sector (UK, Norway etc.) Within each sector the entries are alphabetical by operator name. This index contains page numbers for the book entries: the other two index sections should be used with the main index to find the exact location of an entry; Index by field. If the reader knows a field name (e.g. Kittiwake) but not the operator or the national sector, this index will reference them; Index by installation. Each installation (''Fulmar SALM'', ''Togi'') is named, giving the operator, field and national sector where it is located. This index is also useful for locating particular kinds of installations, such as subsea completions; The book is intended to provide a factual overview of field development activity in the North Sea (a term loosely used to include the Irish Sea and the Baltic Sea). The aim is therefore to provide some background, specifications and history on every offshore installation in that area. Speculative or evaluative commentary is avoided where possible. No attempt has been made to forecast the form or probability of future developments, except in those few instances where announcements have been made by the oil company itself, and these are, clearly indicated. (UK)

  11. 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.

  12. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    The stratigraphic and tectonic evolution of the Jurassic of East Greenland, the Norwegian Shelf and the North Sea is remarkably similar. A major Middle Jurassic unconformity occurs in all three areas. In the North Sea it is commonly termed the `Mid-Cimmerian Unconformity` and is characterized by progressive truncation of the underlying section towards a centre at the triple junction between the Central Graben, Viking Graben and Moray Firth. Strata above the unconformity show a progressive Late Aalenian-Early Kimmeridgian onlap in the same direction. These relations have been interpreted as caused by Early Jurassic uplift and of a major thermal dome in the central North Sea, followed by Medial and Late Jurassic rifting, erosion, deflation and transgression of the dome. The East Greenland unconformity shows progressive truncation of underlying strata from south to north, and Bajocian to Callovian onlap in the same direction. The same pattern seems to be developed on the conjugate Norwegian margin. This suggests the possibility that the three unconformities have similar causes for their development. It is proposed that major rift domes formed in the Central North Sea and in the Greenland-Norway seaway in Early Jurassic times. The domes were eroded and gradually deflated during Medial Jurassic times and were finally submerged by the Late Oxfordian-Kimmeridgian. They were associated with volcanism and rifting which was delayed with respect to dome initiation. Roughly contemperaneous domes were present west of Britain, north of the Porcupine Seabight, and in Scania, southern Sweden, as reflected by development of asymmetrical unconformities showing progressive truncation of underlying strata, onlap of overlying Jurassic strata, and associated intrusive and extrusive volcanism. The domes are related to impingement of the heads of transient mantle plumes at the base of the lithosphere. The associated unconformities are thus of non-eustatic nature. Domal uplift and

  13. 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 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.

  14. Speciated atmospheric mercury in the marine boundary layer of the Bohai Sea and Yellow Sea

    Science.gov (United States)

    Wang, Chunjie; Ci, Zhijia; Wang, Zhangwei; Zhang, Xiaoshan; Guo, Jia

    2016-04-01

    The objectives of this study are to identify the spatial and temporal distributions of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and fine particulate mercury (HgP2.5) in the marine boundary layer (MBL) of the Bohai Sea (BS) and Yellow Sea (YS), and to investigate the relationships between mercury species and meteorological parameters. The mean concentrations of GEM, RGM, and HgP2.5 were 2.03 ng m-3, 2.5 pg m-3, and 8.2 pg m-3 in spring, and 2.09 ng m-3, 4.3 pg m-3, and 8.3 pg m-3 in fall. Reactive mercury (RGM + HgP2.5) represented RGM + HgP2.5), which indicated that most mercury export in the MBL was GEM and the direct outflow of reactive mercury was very small. Moreover, GEM concentrations over the BS were generally higher than those over the YS both in spring and fall. Although RGM showed a homogeneous distribution over the BS and YS both in spring and fall, the mean RGM concentration in fall was significantly higher than that in spring. In contrast, the spatial distribution of HgP2.5 generally reflected a gradient with high levels near the coast of China and low levels in the open sea, suggesting the significant atmospheric mercury outflow from China. Interestingly, the mean RGM concentrations during daytime were significantly higher than those during nighttime both in spring and fall, while the opposite results were observed for HgP2.5. Additionally, RGM positively correlates with air temperature while negatively correlates with relative humidity. In conclusion, the elevated atmospheric mercury levels in the BS and YS compared to other open seas suggested that the human activities had a significant influence on the oceanic mercury cycle downwind of China.

  15. Remotely sensed evidence of the rapid loss of tidal flats in the Yellow Sea

    Science.gov (United States)

    Murray, N. J.; Phinn, S. R.; Clemens, R. S.; Possingham, H.; Fuller, R. A.

    2013-12-01

    In East Asia's Yellow Sea, intertidal wetlands are the frontline ecosystem protecting a coastal population of more than 150 million people from storms and sea-level rise. Despite widespread coastal change and severe modification of the region's major river systems, the magnitude and distribution of coastal wetland loss remains unquantified. We developed a novel remote sensing method to solve the difficult problem of mapping intertidal wetlands over large areas and mapped the extent of tidal flats, the region's primary coastal ecosystem, over 4000kms of coastline at two time periods: the 1980s and late 2000s. We used a regionally validated tide model to identify Landsat images acquired at high and low tides, allowing the area between the high and low tide waterlines to be mapped by differencing classified land-water images between the two tidal stages. Our analysis of the change in areal extent of tidal flats in the Yellow Sea indicates that of the 545,000 ha present in the 1980s, only 389,000 ha remained three decades later, equating to a net loss of 28% at a mean rate of 1.2 % yr-1. ). Comparing the three countries in our analysis, China lost more tidal flat and at a faster rate (39.8%, 1.8% yr-1) than South Korea (32.2%, 1.6% yr-1), and in North Korea minor gains of tidal flat were recorded at (8.5%, 0.3 yr-1). For the same mapped area, historical maps suggest that tidal flats occupied up to 1.14 million ha in the mid-1950s, equating to a potential net loss of up to 65% over ~50 years. Coastal land reclamation for agriculture, aquaculture and urban development is a major driver of tidal flat loss, particularly in China and South Korea, although region-wide declines in sediment replenishment from rivers is also occurring. To conserve the ecosystem services provided by tidal flats and ensure protection of the region's coastal biodiversity, conservation actions should target protection of tidal flats and encourage collaborative and properly planned development

  16. A tax reprieve for the North Sea?

    International Nuclear Information System (INIS)

    Kemp, A.

    1998-01-01

    The United Kingdom government has for the time being put to one side its intended review of the fiscal regime in the North Sea. Consistently low oil prices over the last year and the consequent effect on production have given rise to this decision. The ongoing debate on oil taxation in the UK over the past 18 months since the advent of a new government is examined. It has its roots in the last major changes to the oil tax regime which were made in 1993. It has been made clear by the government that the taxation review has not been abandoned and could come to the fore again should there be a substantial increase in oil and gas prices or if companies sought premature decommissioning of North Sea fields. (UK)

  17. Temperature and water density data from meteorological sensors in the Sea of Japan and Yellow Sea from KODC, 01 January 1923 to 31 December 2001 (NODC Accession 0000914)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and water density data were collected using meteorological sensors from coastal stations in the Sea of Japan and Yellow Sea. Data were submitted by the...

  18. Worldwide market forces threaten North Sea wealth

    Energy Technology Data Exchange (ETDEWEB)

    Booth, D

    1977-01-01

    The challenges that the petroleum industry faces in winning all the oil resources in the North Sea are reviewed. All these hydrocarbons that will soon sustain governments, bolster the standard of living, and bring profits to investors will one day be gone, perhaps. The author says, ''if demand for oil continues to rise by a few percent each year for the next 25 years the prospect of the North Sea drained of its riches is real. Even if Britain makes no more demands on it than those needs of today, the global concept of the oil business will mean that other markets will place the North Sea reserves at risk of exhaustion. Two major factors affect this assumption: market forces and government-implemented depletion rates.'' After explaining these two assumptions, the author graphically portrays what life will be like when petrol becomes a luxury item. It is forgotten that the hydrocarbons are being consumed in a lifetime, when it took several millions of years to put them together. (MCW)

  19. [Spatial heterogeneity in body condition of small yellow croaker in Yellow Sea and East China Sea based on mixed-effects model and quantile regression analysis].

    Science.gov (United States)

    Liu, Zun-Lei; Yuan, Xing-Wei; Yan, Li-Ping; Yang, Lin-Lin; Cheng, Jia-Hua

    2013-09-01

    By using the 2008-2010 investigation data about the body condition of small yellow croaker in the offshore waters of southern Yellow Sea (SYS), open waters of northern East China Sea (NECS), and offshore waters of middle East China Sea (MECS), this paper analyzed the spatial heterogeneity of body length-body mass of juvenile and adult small yellow croakers by the statistical approaches of mean regression model and quantile regression model. The results showed that the residual standard errors from the analysis of covariance (ANCOVA) and the linear mixed-effects model were similar, and those from the simple linear regression were the highest. For the juvenile small yellow croakers, their mean body mass in SYS and NECS estimated by the mixed-effects mean regression model was higher than the overall average mass across the three regions, while the mean body mass in MECS was below the overall average. For the adult small yellow croakers, their mean body mass in NECS was higher than the overall average, while the mean body mass in SYS and MECS was below the overall average. The results from quantile regression indicated the substantial differences in the allometric relationships of juvenile small yellow croakers between SYS, NECS, and MECS, with the estimated mean exponent of the allometric relationship in SYS being 2.85, and the interquartile range being from 2.63 to 2.96, which indicated the heterogeneity of body form. The results from ANCOVA showed that the allometric body length-body mass relationships were significantly different between the 25th and 75th percentile exponent values (F=6.38, df=1737, P<0.01) and the 25th percentile and median exponent values (F=2.35, df=1737, P=0.039). The relationship was marginally different between the median and 75th percentile exponent values (F=2.21, df=1737, P=0.051). The estimated body length-body mass exponent of adult small yellow croakers in SYS was 3.01 (10th and 95th percentiles = 2.77 and 3.1, respectively). The

  20. Composite Earthquake Catalog of the Yellow Sea for Seismic Hazard Studies

    Science.gov (United States)

    Kang, S. Y.; Kim, K. H.; LI, Z.; Hao, T.

    2017-12-01

    The Yellow Sea (a.k.a West Sea in Korea) is an epicontinental and semi-closed sea located between Korea and China. Recent earthquakes in the Yellow Sea including, but not limited to, the Seogyuckryulbi-do (1 April 2014, magnitude 5.1), Heuksan-do (21 April 2013, magnitude 4.9), Baekryung-do (18 May 2013, magnitude 4.9) earthquakes, and the earthquake swarm in the Boryung offshore region in 2013, remind us of the seismic hazards affecting east Asia. This series of earthquakes in the Yellow Sea raised numerous questions. Unfortunately, both governments have trouble in monitoring seismicity in the Yellow Sea because earthquakes occur beyond their seismic networks. For example, the epicenters of the magnitude 5.1 earthquake in the Seogyuckryulbi-do region in 2014 reported by the Korea Meteorological Administration and China Earthquake Administration differed by approximately 20 km. This illustrates the difficulty with seismic monitoring and locating earthquakes in the region, despite the huge effort made by both governments. Joint effort is required not only to overcome the limits posed by political boundaries and geographical location but also to study seismicity and the underground structures responsible. Although the well-established and developing seismic networks in Korea and China have provided unprecedented amount and quality of seismic data, high quality catalog is limited to the recent 10s of years, which is far from major earthquake cycle. It is also noticed the earthquake catalog from either country is biased to its own and cannot provide complete picture of seismicity in the Yellow Sea. In order to understand seismic hazard and tectonics in the Yellow Sea, a composite earthquake catalog has been developed. We gathered earthquake information during last 5,000 years from various sources. There are good reasons to believe that some listings account for same earthquake, but in different source parameters. We established criteria in order to provide consistent

  1. Flight feather molt in Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) in North Dakota

    Science.gov (United States)

    Twedt, Daniel J.; Linz, George M.

    2015-01-01

    Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) in central North Dakota undergo prebasic molt or prejuvenile molt during late summer. Nestling Yellow-headed Blackbirds initiate a complete prejuvenile molt, grow their primary and secondary regimes in about 40 days, completing molt after they leave the nest by the first week in August. Remiges are not replaced during the subsequent preformative molt, being retained until the second prebasic molt. Nonlinear (logistic) regression of primary remex growth during definitive prebasic molts of Yellow-headed Blackbirds indicated 38 days were required to complete the linear phase of growth (between 10% and 90% of total primary length). Males added 19.5 mm/d and females added 15.7 mm/d to the total length of all primaries during this linear growth phase; an average of 4–5 mm per primary remex per day. Definitive prebasic molting of primary remiges in males and females was initiated in late June, after nesting and brood rearing were completed. Molts of Yellow-headed Blackbirds were completed by early September, before birds emigrated from North Dakota during mid-September. Because of their comparatively early completion of molt and emigration from the state, as well as their more diverse diet, agricultural depredation caused by Yellow-headed Blackbirds in North Dakota is likely less than that of Red-winged Blackbirds and Common Grackles.

  2. Bacterial and archaeal communities in sediments of the north Chinese marginal seas.

    Science.gov (United States)

    Liu, Jiwen; Liu, Xiaoshou; Wang, Min; Qiao, Yanlu; Zheng, Yanfen; Zhang, Xiao-Hua

    2015-07-01

    Microbial communities of the Chinese marginal seas have rarely been reported. Here, bacterial and archaeal community structures and abundance in the surface sediment of four sea areas including the Bohai Sea (BS), North Yellow Sea (NYS), South Yellow Sea (SYS), and the north East China Sea (NECS) were surveyed by 16S ribosomal RNA (rRNA) gene pyrosequencing and quantitative PCR. The results showed that microbial communities of the four geographic areas were distinct from each other at the operational taxonomic unit (OTU) level, whereas the microbial communities of the BS, NYS, and SYS were more similar to each other than to the NECS at higher taxonomic levels. Across all samples, Bacteria were numerically dominant relative to Archaea, and among them, Gammaproteobacteria and Euryarchaeota were predominant in the BS, NYS, and SYS, while Deltaproteobacteria and Thaumarchaeota were prevalent in the NECS. The most abundant bacterial genera were putative sulfur oxidizer and sulfate reducer, suggesting that sulfur cycle processes might prevail in these areas, and the high abundance of dsrB (10(7)-10(8) copies g(-1)) in all sites verified the dominance of sulfate reducer in the north Chinese marginal seas. The differences in sediment sources among the sampling areas were potential explanations for the observed microbial community variations. Furthermore, temperature and dissolved oxygen of bottom water were significant environmental factors in determining both bacterial and archaeal communities, whereas chlorophyll a in sediment was significant only in structuring archaeal community. This study presented an outline of benthic microbial communities and provided insights into understanding the biogeochemical cycles in sediments of the north Chinese marginal seas.

  3. Annually recurrent macroalgal blooms (Ulva prolifera) resulting in the world's largest green-tides caused by expansion of coastal aquaculture in the Yellow Sea off China

    Science.gov (United States)

    Keesing, John; Liu, Dongyan

    2013-04-01

    The largest macroalgal blooms ever recorded occurred in the Yellow Sea of China in 2008 and 2009 and resulted in extensive green tides along the Shandong Province coastline, including at Qingdao. At their peak these Ulva prolifera blooms covered more than 4,000 km2 and affected 40,000 km2. A smaller bloom was recorded in 2007, but not earlier. Since then massive blooms have occurred annually in summer from 2008 to 2012. Using remote sensing methods, we tracked the source of the 2008 and 2009 blooms to an area along the Jiangsu Province coastline near Yancheng, over 200 km south of Qingdao, where there had been rapid expansion of Porphyra aquaculture to as much as 13 km offshore, prior to the appearance of the first bloom in 2007. Porphyra is grown on rafts which can become heavily fouled with U. prolifera which is disposed of into the sea when the Porphyra is harvested. The timing of the blooms occurred post the April harvest period when daily tidal ranges in this region can be in excess of 7 m. This provides the mechanism for transportation of the floating algae offshore and into the warm nutrient rich waters of the Yellow Sea where it grows rapidly forming large patches. As the patches of algae grow and join, they gradually move north, as a result of wind driven surface currents that prevail in the Yellow Sea in summer, ultimately washing ashore on the Shandong Peninsula. We present a range of oceanographic, biological, ecological and genetic data to support the hypothesis that Porphyra aquaculture provides the source biomass for the Yellow Sea green-tides. Improved aquaculture waste disposal methods in the southern area of Jiangsu Province are likely to reduce or prevent the Yellow Sea green tides and present a feasible solution to a recurrent problem.

  4. CNA Maritime Asia Project. Workshop One: The Yellow and East China Seas

    Science.gov (United States)

    2012-05-01

    in 2011.8 In October, South Korean Coast Guard forces used tear gas and rubber bullets to subdue Chinese fishermen wielding clubs and shovels.9 An...tation Disputes in the East China Sea,” NBR Special Report No.35 (December 2011): 135 and 141. 39 CNA Maritime Asia Project Workshop One: The Yellow

  5. Pseudocollapse and rebuilding of North Sea mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis

    2014-01-01

    The largest observed change in mackerel (Scomber scombrus) abundance in the North Atlantic happened when the so-called “North Sea mackerel” collapsed due to overfishing. Despite protection, it has remained in a depleted state. Central to this interpretation was that the “North Sea mackerel...

  6. Genetic differentiation in Japanese flounder in the Yellow Sea and ...

    African Journals Online (AJOL)

    Jane

    2011-10-05

    Oct 5, 2011 ... diversity (H) and Shannon's information index (I) values were higher in the Qingdao population (P = 72.85% ... Based on the COI sequencing analysis, a total of 25 polymorphic sites ..... and recruitment in the East China Sea.

  7. North Sea oil and the environment

    International Nuclear Information System (INIS)

    Cairns, W.J.

    1992-01-01

    This book, which is arranged in five sections, provides an historical record of the development of North Sea oil and gas over the past twenty years and records the lessons learnt from this experience. This first section provides an introductory framework to the three main themes, namely resources, environment and development. Section 2 is primarily concerned with the economic and social consequences of oil related development at two levels; firstly on the national economy and secondly the impact on local communities. Section 3 deals with impacts upon the physical environment and introduces the statutory land use planning system in Scotland. The Scottish approach to environmental assessment is reviewed and the need for mitigation by design explored. Section 4 examines specific field developments, and reviews the statutory controls and international initiatives regulating the extent of environmental disturbance and pollution from offshore operations. The effects of oil spillage and submarine pipelines on the environment and their impact on the fishing industry is followed by a discussion on the decommissioning and abandonment of offshore installations. Section 5 deals with the role and value of hazard and risk analysis in the siting, layout and safety zoning of onshore facilities and develops a case study on a major fractionation facility. The means of mitigating acute and chronic environmental risks are considered. A postscript provides a range of past comments and criticisms and finally draws some conclusions on the performance of environmental management and North Sea oil development. The North Sea oil and gas development experience proves that with wisdom, forethought and goodwill, industrial exploiters of natural resources can operate economically within legislative, policy, scientific, technical and design parameters without causing long-term irreversible environmental damage. (author)

  8. Petroleum Economist's 1993 North Sea survey

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A survey is presented for 51 oil fields in the North Sea belonging to the United Kingdom, 17 belonging to Norway, 4 belonging to the Netherlands and 7 belonging to Denmark. Similarly data is presented for 32 gas fields belonging to the United Kingdom, 5 belonging to Norway, 42 belonging to the Netherlands, and 1 belonging to Denmark. The information given in the surveys includes the original recoverable reserves, remaining reserves, water depth, gravity, sulphur content, discovery date, start-up date, participants and production. (U.K.)

  9. Report from Holland: the economics of North Sea hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Ellman, M

    1977-09-01

    The article describes how, despite huge revenues from North Sea gas, Holland is currently suffering from unemployment and its long-term prospects are poor. In light of this, Mr. Ellman discusses the implications of North Sea oil for the UK economy. He sites three distinguishable policies that the UK government could adopt in the face of the huge import saving and export creation that North Sea hydrocarbons will soon bring--sound finance, demand management, and structural modernization. (MCW)

  10. 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)...

  11. North Sea focus on radwaste disposal

    International Nuclear Information System (INIS)

    Cope, D.

    1990-01-01

    At the recent North Sea Conference in the Netherlands possible future strategies for managing radioactive waste (radwaste) proved to be a contentious issue. Several of its North Sea littoral neighbours sought a categorical assurance that the UK would forego the option of constructing a subterranean radwaste repository which though accessed from land, extends under the coastline, or a sub-seabed facility reached from an offshore structure. It was pointed out that the UK has no present plans for such a radwaste repository. However, sub-seabed designs as a possibility for future repositories were not ruled out. NIREX has decided to concentrate its exploration work at two sites -Sellafield and Dounreay. Both sites are coastal locations and the government is aware that detailed geological exploration may favour extension of a radwaste repository beyond the shoreline, even if initially developed entirely on land. The design of such a radioactive waste repository is outlined. The position of NIREX and the Radioactive Waste Management Advisory Committee is discussed. (author)

  12. Temporal Evolution of the Yellow Sea Ecosystem Services (1980–2010

    Directory of Open Access Journals (Sweden)

    Qixiang Wang

    2016-03-01

    Full Text Available Marine ecosystem services refer to benefits that people obtain from marine ecosystem. Understanding temporal evolution of these services is a fundamental challenge of natural resource management in marine ecosystems. Yellow Sea is one of the most intensely exploited shallow seas in the Northwest Pacific Ocean. In this study, we analyzed the value of the four classes services (provisioning services, regulating services, cultural services and supporting services, including 14 individual services of the Yellow Sea on temporal scales. From 1980 to 2010, the total value of the four classes of services was between 297 and 2,232 billion RMB yuan. Only the proportion of cultural services as a percentage of the total value continued to increase for the entire period, from 0.9% in 1980 to 9.4% in 2010. Provisioning services reached their highest point at 18.4% in 2000, and then fell to 10.1% in 2010. Meanwhile, the percentage of regulating services and supporting services declined, falling from 14.4% and 79.4% in 1980 to 10.1% and 70.4% in 2010, respectively. This study represents the first attempt to analyze the temporal evolution of Yellow Sea ecosystem services. It will provide the theoretical basis for further study of the ecological mechanisms of marine ecosystem services.

  13. Linear mixed-effects models to describe length-weight relationships for yellow croaker (Larimichthys Polyactis) along the north coast of China.

    Science.gov (United States)

    Ma, Qiuyun; Jiao, Yan; Ren, Yiping

    2017-01-01

    In this study, length-weight relationships and relative condition factors were analyzed for Yellow Croaker (Larimichthys polyactis) along the north coast of China. Data covered six regions from north to south: Yellow River Estuary, Coastal Waters of Northern Shandong, Jiaozhou Bay, Coastal Waters of Qingdao, Haizhou Bay, and South Yellow Sea. In total 3,275 individuals were collected during six years (2008, 2011-2015). One generalized linear model, two simply linear models and nine linear mixed effect models that applied the effects from regions and/or years to coefficient a and/or the exponent b were studied and compared. Among these twelve models, the linear mixed effect model with random effects from both regions and years fit the data best, with lowest Akaike information criterion value and mean absolute error. In this model, the estimated a was 0.0192, with 95% confidence interval 0.0178~0.0308, and the estimated exponent b was 2.917 with 95% confidence interval 2.731~2.945. Estimates for a and b with the random effects in intercept and coefficient from Region and Year, ranged from 0.013 to 0.023 and from 2.835 to 3.017, respectively. Both regions and years had effects on parameters a and b, while the effects from years were shown to be much larger than those from regions. Except for Coastal Waters of Northern Shandong, a decreased from north to south. Condition factors relative to reference years of 1960, 1986, 2005, 2007, 2008~2009 and 2010 revealed that the body shape of Yellow Croaker became thinner in recent years. Furthermore relative condition factors varied among months, years, regions and length. The values of a and relative condition factors decreased, when the environmental pollution became worse, therefore, length-weight relationships could be an indicator for the environment quality. Results from this study provided basic description of current condition of Yellow Croaker along the north coast of China.

  14. Elemental mercury in coastal seawater of Yellow Sea, China: Temporal variation and air-sea exchange

    Science.gov (United States)

    Ci, Zhijia; Zhang, Xiaoshan; Wang, Zhangwei

    2011-01-01

    Dissolved gaseous mercury (DGM, largely Hg(0)) in coastal seawater and gaseous elemental mercury (GEM or Hg(0)) in the atmosphere were simultaneously measured on the coast of the Yellow Sea, China in four different seasons (2008-09). Mean concentrations (±SD) of DGM and GEM over the study period were 34.0 ± 26.1 pg L -1 and 2.55 ± 0.98 ng m -3, respectively. DGM concentrations and the degree of DGM saturation ( Sa) exhibited distinct seasonal variation with the order of summer (DGM: 69.0 ± 23.3 pg L -1, Sa: 11.00 ± 5.92) > fall (27.0 ± 16.4 pg L -1, 3.50 ± 2.60) > spring (23.0 ± 8.7 pg L -1, 2.00 ± 0.98) > winter (16.0 ± 6.0 pg L -1, 0.96 ± 0.39). Under typical meteorological condition with low wind speed and intensive solar radiation in warm seasons, DGM usually exhibited the clear diurnal variation with elevated levels around noon and low levels in morning and afternoon. The diurnal and seasonal variation of DGM indicated the importance of photochemical DGM formation in the seawater. A consistent low DGM levels in high wind speed condition suggested that the biological activity probably influenced the DGM formation. There was no significant correlation between DGM and total mercury (THg), reactive mercury (RHg), dissolved organic carbon (DOC) in the seawater, indicating that THg/RHg and DOC might be not the controlling factors for the DGM formation in our study region. Based on the data of DGM and GEM and a two-layer gas exchange model, Hg(0) fluxes (in the unit of ng m -2 h -1) at air-sea interface were 0.51 ± 1.29 over the entire study period with 0.89 ± 1.84 in fall, 0.88 ± 1.38 in summer, 0.32 ± 0.71 in spring, and -0.06 ± 0.64, a slightly net Hg(0) deposition rate, in winter, respectively.

  15. Recent Primary Production and Small Phytoplankton Contribution in the Yellow Sea during the Summer in 2016

    Science.gov (United States)

    Jang, Hyo Keun; Kang, Jae Jung; Lee, Jae Hyung; Kim, Myungjoon; Ahn, So Hyun; Jeong, Jin-Yong; Yun, Mi Sun; Han, In-Seong; Lee, Sang Heon

    2018-05-01

    The high nutrient concentration associated with the mixing dynamics of two warm and cold water masses supports high primary production in the Yellow Sea. Although various environmental changes have been reported, no recent information on small phytoplankton contribution to the total primary production as an important indicator for marine ecosystem changes is currently available in the Yellow Sea. The major objective of this study is to determine the small (values decades ago. The higher contributions of small phytoplankton to the total chlorophyll a concentration and primary production might be caused by P-limited conditions and this resulted in lower chlorophyll a concentration and total primary production in this study compared to previous studies.

  16. Genetic analysis of floating Enteromorpha prolifera in the Yellow Sea with AFLP marker

    Science.gov (United States)

    Liu, Cui; Zhang, Jing; Sun, Xiaoyu; Li, Jian; Zhang, Xi; Liu, Tao

    2011-09-01

    Extremely large accumulation of green algae Enteromorpha prolifera floated along China' coastal region of the Yellow Sea ever since the summer of 2008. Amplified Fragment Length Polymorphism (AFLP) analysis was applied to assess the genetic diversity and relationships among E. prolifera samples collected from 9 affected areas of the Yellow Sea. Two hundred reproducible fragments were generated with 8 AFLP primer combinations, of which 194 (97%) were polymorphic. The average Nei's genetic diversity, the coefficiency of genetic differentiation (Gst), and the average gene flow estimated from Gst in the 9 populations were 0.4018, 0.6404 and 0.2807 respectively. Cluster analysis based on the unweighed pair group method with arithmetic averages (UPGMA) showed that the genetic relationships within one population or among different populations were all related to their collecting locations and sampling time. Large genetic differentiation was detected among the populations. The E. prolifera originated from different areas and were undergoing a course of mixing.

  17. Scientific symposium on the North Sea quality status report 1993

    International Nuclear Information System (INIS)

    Andersen, J.; Karup, H.; Nielsen, U.B.

    1996-01-01

    The Scientific Symposium on the 1993 North Sea quality Status Report took place in Ebeltoft, Denmark from 18 to 21 April 1994. The aim was to bring together scientists, researchers and administrators from governments, industries and environmental organizations from the countries around the North Sea in order to review new information which may supplements the 1993 North Sea Quality Status Report and to discuss the Quality Status Report and its possible implications. The 1993 North Sea Quality Status Report has been prepared by the North Sea Task force as a comprehensive statement of circulation patterns, inputs and dispersion of contaminants, ecological conditions and effects of human activities in the North Sea including the Skagerrak and the Kattegat. The programme of the Scientific Symposium on the 1993 North Sea Quality Status Report included 8 sessions for oral presentations, a poster session presenting the North Sea Task Force subregional reports and a poster session presenting individual posters. The headings of the sessions were as follows: Oceanography, Models and Remote Sensing; Ecosystem Structure; Contaminants -Distribution and Effects; Nutrients and Eutrophication Problems; Effects of Fishery; Habitats and Species; Management Implications; Conclusions and Recommendations. The proceedings includes a total of 45 contributed papers. (EG)

  18. Submarine pipelines and the North Sea environment

    International Nuclear Information System (INIS)

    Haldane, D.; Paul, M.A.; Reuben, R.L.; Side, J.C.

    1992-01-01

    The function and design of pipelines for use on the United Kingdom continental shelf are described. Environmental influences which can threaten the integrity of seabed pipelines in the North Sea include hydrodynamic forces due to residual, tidal and wave currents, the nature of seabed sediments and corrosion by seawater. Damage may be caused to pipelines by interaction with vessel anchors and with fishing gear. Special care has to be taken over the selection of the general area for the landfall of a pipeline and the engineering of the installation where the pipeline comes ashore. Trenching and other protection techniques for pipelines are discussed together with hydrostatic testing and commissioning and subsequent inspection, maintenance and repair. (UK)

  19. Deposition of nitrogen into the North Sea

    DEFF Research Database (Denmark)

    Leeuw, G. de; Skjøth, C.A.; Hertel, O.

    2003-01-01

    The flux of nitrogen species from the atmosphere into the ocean, with emphasis on coastal waters, was addressed during the ANICE project (Atmospheric Nitrogen Inputs into the Coastal Ecosystem). ANICE focused on quantifying the deposition of atmospheric inputs of inorganic nitrogen compounds (HNO3...... and Harwich/Newcastle. These measurements provided data for sensitivity studies of a variety of problems associated with the coastal region that are not easily evaluated with larger scale models, to constrain models and to test model results. Concentrations of nitrogen compounds over the North Sea...... on experimental results and small-scale model studies. In particular, effects of the aerosol size distribution on the nitrogen deposition are discussed. (C) 2003 Elsevier Ltd. All rights reserved....

  20. Occurrence and Biological Fate of Persistent Organic Contaminants in Yellow Sea Fish

    Directory of Open Access Journals (Sweden)

    Narayanan Kannan

    2010-01-01

    Full Text Available Persistent Organic Pollutants (POPs, namely, Polychlorinated biphenyls (PCBs, DDTs, HCHs, HCB, aldrin, endrin, dieldrin, endosulfan, heptachlors, mirex and chlordane compounds were investigated in muscle and liver tissues of Yellow Sea croakers (Collichthys niveatus and Pseudosciaena crocea from 16 stations on the off shore waters of South Korea within the Yellow Sea Large Marine Ecosystem (YSLME. The sum concentration (minimum-maximum - ng/g lipid wt. was: PCBs: non-detectable to 21; Pesticides non-detectable to 63. Among the 26 individual pesticide compounds measured in fishes, except 1,2,4,5-tetrachlorobenzene (TCBZ, all the other compounds were determined in almost in all samples. The levels in Yellow Sea croakers were similar to levels reported in the Baltic fish. The differential ratios of isomers/congeners in biota in comparison to the original commercial mixtures suggest possible metabolism by cytochrome P450 isozymes. The induction of such drug metabolizing enzymes suggests an ecotoxicological stress. Principle Component Analysis identifies ‘hot spots’ within the sampled area including the Korean off shore sewage dumpsite.

  1. Biomagnification of persistent chlorinated and brominated contaminants in food web components of the Yellow Sea

    International Nuclear Information System (INIS)

    Byun, Gyo-Hyuk; Moon, Hyo-Bang; Choi, Jung-Hwa; Hwang, Jeomshik; Kang, Chang-Keun

    2013-01-01

    Highlights: • PCBs, OCPs, and PBDEs were analyzed for 32 marine species in the Yellow Sea. • Their bioaccumulation potentials were assessed in combination with stable isotopes. • Pelagic and benthic food-chain components were separated by their δ 13 C values. • Pelagic food chain was a major bioaccumulation pathway for selected PCBs and OCPs. • The other compounds displayed low bioaccumulation potentials through food chains. -- Abstract: Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in 32 species inhabiting the Yellow Sea to assess their bioaccumulation potentials. The concentrations in these samples were lower than those reported for other countries or locations. Relatively high levels of BDE 209 in biota suggest an ongoing source of deca-BDE technical mixing within the Yellow Sea. The accumulation profiles of PCBs were uniform between species, but the concentrations of OCPs and PBDEs varied widely. Pelagic and benthic food-chain components were separated by their δ 13 C values. Significant positive correlations between δ 15 N and PCB 153, PCB 138, p,p′-DDE, oxy-chlordane, and trans-nonachlordane were found only for pelagic consumers, indicating that the pelagic food chain is an important bioaccumulation pathway for selected PCB and OCP compounds. The other compounds did not show any biomagnification through benthic and pelagic food chains, suggesting the lower bioaccumulation potentials of these contaminants

  2. Air-sea heat flux control on the Yellow Sea Cold Water Mass intensity and implications for its prediction

    Science.gov (United States)

    Zhu, Junying; Shi, Jie; Guo, Xinyu; Gao, Huiwang; Yao, Xiaohong

    2018-01-01

    The Yellow Sea Cold Water Mass (YSCWM), which occurs during summer in the central Yellow Sea, plays an important role in the hydrodynamic field, nutrient cycle and biological species. Based on water temperature observations during the summer from 1978 to 1998 in the western Yellow Sea, five specific YSCWM years were identified, including two strong years (1984 and 1985), two weak years (1989 and 1995) and one normal year (1992). Using a three-dimensional hydrodynamic model, the YSCWM formation processes in these five years were simulated and compared with observations. In general, the YSCWM began forming in spring, matured in summer and gradually disappeared in autumn of every year. The 8 °C isotherm was used to indicate the YSCWM boundary. The modelled YSCWM areas in the two strong years were approximately two times larger than those in the two weak years. Based on the simulations in the weak year of 1995, ten numerical experiments were performed to quantify the key factors influencing the YSCWM intensity by changing the initial water condition in the previous autumn, air-sea heat flux, wind, evaporation, precipitation and sea level pressure to those in the strong year of 1984, respectively. The results showed that the air-sea heat flux was the dominant factor influencing the YSCWM intensity, which contributed about 80% of the differences of the YSCWM average water temperature at a depth of 50 m. In addition, the air-sea heat flux in the previous winter had a determining effect, contributing more than 50% of the differences between the strong and weak YSCWM years. Finally, a simple formula for predicting the YSCWM intensity was established by using the key influencing factors, i.e., the sea surface temperature before the cooling season and the air-sea heat flux during the cooling season from the previous December to the current February. With this formula, instead of a complicated numerical model, we were able to roughly predict the YSCWM intensity for the

  3. Retrieval of Secchi disk depth in the Yellow Sea and East China Sea using 8-day MODIS data

    International Nuclear Information System (INIS)

    Yu, D F; Xing, Q G; Lou, M J; Shi, P

    2014-01-01

    Secchi disk depth (SDD), is widely used as an indicator of water clarity. The traditional sampling method is not only time-consuming and labor-intensive but also limited in terms of temporal and spatial coverage. Remote sensing technology may deal with these limitations. In this paper, the applicability of 8-day MODIS-Aqua remote sensing reflectance data with 4 km spatial resolution for estimating water clarity in the Yellow Sea and the East China Sea was investigated. Field data such as Secchi depths were collected from two cruises conducted in the Yellow Sea and the East China Sea from 5 May to 7 June 2009. A three-band algorithm to retrieve SDD was developed based on remote sensing reflectance at bands of 488, 555, and 678 nm, which performed better than single-band model and band ratio algorithm, with a determination coefficient of 0.72 and a mean relative error of 19%. This suggests that 8-day MODIS-Aqua products of remote sensing reflectance could be used to assess water transparency in the study area

  4. 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

  5. Why is the North Sea West of Us?

    DEFF Research Database (Denmark)

    Gammeltoft, Peder

    2016-01-01

    . Occurrences of sea names such as the North Sea are examined and analysed to see how they spread from an original one-language form to exist in multiple languages, and analyses them from a linguistic, geographic and nautical perspective. It is found that Seas or bodies of water in stretches of sea are named......This article focuses on the motivations behind sea-naming, by means of examples from Europe but also elsewhere. Why do certain sea names become dominant while others retract into local forms or simply die out? The article takes us back in time to the early days of map-making and, indeed, earlier...

  6. Ecology and conservation of North American sea ducks

    Science.gov (United States)

    Savard, Jean-Pierre L.; Derksen, Dirk V.; Esler, Daniel N.; Eadie, John M.

    2015-01-01

    The past decade has seen a huge increase in the interest and attention directed toward sea ducks, the Mergini tribe. This has been inspired, in large part, by the conservation concerns associated with numerical declines in several sea duck species and populations, as well as a growing appreciation for their interesting ecological attributes. Reflecting the considerable research recently conducted on this tribe, Ecology and Conservation of North American Sea Ducks examines the 15 extant species of sea ducks from North America.

  7. North Sea oil taxation in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, A G; Crichton, D

    1979-01-01

    The Norwegian government has developed a complex fiscal regime since 1963 to cover the activities of oil companies in the North Sea. The purpose of this article is to identify and quantify the financial effects of the fiscal system on operating companies involved in the Norwegian sector. The emphasis is on the effect of the tax package introduced by the government in the Odelsting Proposition No. 26 of February 1975. The impact of the tax is not found to be well related to the profitability of fields and the sensitivity of the tax burden to key variables such as reserves, oil price, capital and operating costs and inflation is examined. The most promising change appears to be a discriminatory refund or remission of royalty payments to marginal fields. The Act's main innovation, Special Tax, fails to discriminate between fields of profitability and could influence development decisions in marginal fields. The special allowance provision, by reducing the real cost of capital expenditure and favoring capital-intensive operations, could influence the techniques of exploitation. The effect of quasi-fiscal measures, particularly of government participation via Statoil, is also examined. 10 references.

  8. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  9. Variation in the macrofaunal community over large temporal and spatial scales in the southern Yellow Sea

    Science.gov (United States)

    Xu, Yong; Sui, Jixing; Yang, Mei; Sun, Yue; Li, Xinzheng; Wang, Hongfa; Zhang, Baolin

    2017-09-01

    To detect large, temporal- and spatial-scale variations in the macrofaunal community in the southern Yellow Sea, data collected along the western, middle and eastern regions of the southern Yellow Sea from 1958 to 2014 were organized and analyzed. Statistical methods such as cluster analysis, non-metric multidimensional scaling ordination (nMDS), permutational multivariate analysis of variance (PERMANOVA), redundancy analysis (RDA) and canonical correspondence analysis (CCA) were applied. The abundance of polychaetes increased in the western region but decreased in the eastern region from 1958 to 2014, whereas the abundance of echinoderms showed an opposite trend. For the entire macrofaunal community, Margalef's richness (d), the Shannon-Wiener index (H‧) and Pielou's evenness (J‧) were significantly lower in the eastern region when compared with the other two regions. No significant temporal differences were found for d and H‧, but there were significantly lower values of J‧ in 2014. Considerable variation in the macrofaunal community structure over the past several decades and among the geographical regions at the species, genus and family levels were observed. The species, genera and families that contributed to the temporal variation in each region were also identified. The most conspicuous pattern was the increase in the species Ophiura sarsii vadicola in the eastern region. In the western region, five polychaetes (Ninoe palmata, Notomastus latericeus, Paralacydonia paradoxa, Paraprionospio pinnata and Sternaspis scutata) increased consistently from 1958 to 2014. The dominance curves showed that both the species diversity and the dominance patterns were relatively stable in the western and middle regions. Environmental parameters such as depth, temperature and salinity could only partially explain the observed biological variation in the southern Yellow Sea. Anthropogenic activities such as demersal fishing and other unmeasured environmental variables

  10. Tracing the origin of paralytic shellfish toxins in scallop Patinopecten yessoensis in the northern Yellow Sea.

    Science.gov (United States)

    Chen, Jian-Hua; Yu, Ren-Cheng; Gao, Yan; Kong, Fan-Zhou; Wang, Yun-Feng; Zhang, Qing-Chun; Kang, Zhen-Jun; Yan, Tian; Zhou, Ming-Jiang

    2013-01-01

    Some dinoflagellate species within the genera Alexandrium, Gymnodinium and Pyrodinium are well-known producers of paralytic shellfish toxins (PST), which led to many poisoning incidents around the world. In the northern Yellow Sea, an important mariculture zone for scallop Patinopecten yessoensis, PST have been frequently detected from scallops. However, there is little knowledge concerning PST-producing microalgae in this region so far. In cruises carried out in 2011 and 2012, scallop and phytoplankton samples were collected from the northern Yellow Sea. PST were detected from scallops by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Toxin content and profile were remarkably different among the four tissues, i.e. viscera, adductor muscle, mantle and gonad, suggesting apparent toxin transfer and transformation in scallops. Viscera always had the highest content of PST dominated by low-potency N-sulfocarbamoyl toxins C1 and C2, which closely resembled the toxin profiles of net-concentrated phytoplankton samples in spring. Based on the morphological features, cells of Alexandrium spp. in net-concentrated phytoplankton samples were picked out and a partial sequence of the large subunit ribosomal RNA gene (LSU rDNA) was amplified using a single-cell polymerase chain reaction (PCR) method. Cells of both toxic A. tamarense species complex and non-toxic A. affine were identified from the phytoplankton samples based on the partial LSU rDNA sequence information. According to these findings, it is implied that A. tamarense species complex is the major toxic species related to PST contamination in scallops of the northern Yellow Sea. The presence of both toxic and non-toxic Alexandrium spp. in this region requires for a species-specific method to monitor the distribution and dynamics of A. tamarense species complex.

  11. Trophic interactions, ecosystem structure and function in the southern Yellow Sea

    Science.gov (United States)

    Lin, Qun; Jin, Xianshi; Zhang, Bo

    2013-01-01

    The southern Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. A trophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to >V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum's ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.

  12. North Sea ecosystem change from swimming crabs to seagulls.

    Science.gov (United States)

    Luczak, C; Beaugrand, G; Lindley, J A; Dewarumez, J-M; Dubois, P J; Kirby, R R

    2012-10-23

    A recent increase in sea temperature has established a new ecosystem dynamic regime in the North Sea. Climate-induced changes in decapods have played an important role. Here, we reveal a coincident increase in the abundance of swimming crabs and lesser black-backed gull colonies in the North Sea, both in time and in space. Swimming crabs are an important food source for lesser black-backed gulls during the breeding season. Inhabiting the land, but feeding mainly at sea, lesser black-backed gulls provide a link between marine and terrestrial ecosystems, since the bottom-up influence of allochthonous nutrient input from seabirds to coastal soils can structure the terrestrial food web. We, therefore, suggest that climate-driven changes in trophic interactions in the marine food web may also have ensuing ramifications for the coastal ecology of the North Sea.

  13. Hydrocarbon preservation conditions in Mesozoic–Paleozoic marine strata in the South Yellow Sea Basin

    Directory of Open Access Journals (Sweden)

    Jie Liang

    2017-11-01

    Full Text Available In the South Yellow Sea Basin, Mesozoic–Paleozoic marine strata are generally well developed with large thickness, and they are characterized by multi-source and multi-stage hydrocarbon accumulation, providing a material basis for the formation of large-scale oil and gas fields. However, no substantial breakthrough has been made in this area. Based on previous research results, the complex tectonic pattern of this superimposed basin was formed by multi-stage tectonic movements and the favorable static conditions for hydrocarbon preservation were reworked or destroyed by later superimposition. Therefore, hydrocarbon preservation conditions are the key factors for restricting the breakthrough of marine oil and gas exploration in this area. In this paper, hydrocarbon preservation conditions of marine strata in the South Yellow Sea Basin were comprehensively analyzed from many aspects, such as tectonic movement, source conditions, caprock characteristics, magmatic activities, and hydrogeological and hydrogeochemical characteristics. It is indicated that the complex tectonic pattern of the South Yellow Sea Basin is resulted from tectonic events in multiple stages, and the development and evolution of regional source rocks are mainly controlled by two stages (i.e., the stable evolution stage of Mesozoic–Paleozoic marine basin and the Mesozoic–Cenozoic tectonic pattern transformation and basin formation stage, so the characteristics of differential oil and gas preservation are presented. Besides, better marine hydrocarbon preservation preconditions in this area are weaker tectonic reworking, development of high-quality thick source rocks, good vertical sealing capacity of caprocks, weaker magmatic activity and confined hydrogeological conditions. It is concluded that the Laoshan Uplift in the central part of the South Yellow Sea Basin is structurally stable with weaker faulting and magmatic activities, so it is better in oil and gas preservation

  14. Sea turtles sightings in North Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles sightings are reported to the NMFS Beaufort Laboratory sea turtle program by the general public as they are fishing, boating, etc. These sightings...

  15. Detection of Total and Pathogenic Vibrio parahaemolyticus in Shellfish Growing along the South Yellow Sea and the East China Sea.

    Science.gov (United States)

    Han, Feng; Gu, Run-Run; Shen, Xiao-Sheng; Chen, Yuan-Ge; Tian, Liang-Liang; Zhou, Wei-Feng; Cai, You-Qiong

    2017-10-17

    This study was conducted to monitor the densities of total and pathogenic Vibrio parahaemolyticus in 300 samples of nine shellfish species harvested from the coasts of the South Yellow Sea and the East China Sea (N 23° to 34°, E 116° to 124°), People's Republic of China, between May and October 2015. Total V. parahaemolyticus densities were measured, and V. parahaemolyticus isolates were biochemically identified with probes for the thermostable direct hemolysin gene (tdh) and the thermostable direct hemolysin-related hemolysin gene (trh). We found that 202 of the 300 samples were positive for V. parahaemolyticus from all the sites: 58 of the 100 samples from the Fujian province, 71 of the 100 samples from the Zhejiang province, and 73 of the 100 samples from the Jiangsu province. In most (170) of the 300 samples, V. parahaemolyticus densities were 0.3 to 10 most probable number (MPN)/g; five lots exceeded 110 MPN/g, and two lots were estimated at 110 MPN/g. Among the 202 V. parahaemolyticus strains, only one was trh positive. Densities of V. parahaemolyticus in these shellfish were temperature dependent, with highest densities in June and July. Among the nine mollusk species, V. parahaemolyticus was most abundant in the agemaki clam (Sinonovacula constricta). The highest and lowest V. parahaemolyticus prevalences were found in oriental cyclina (Cyclina sinensis, 93.8%) and mussels (Mytilus edulis, 28.1%), respectively. Overall, although V. parahaemolyticus is widely distributed in marine environments, the density of V. parahaemolyticus was low and the prevalence of the main virulence factor was very low in shellfish along the coasts of the South Yellow Sea and East China Sea, which is important from a public health perspective. Data presented here will be useful for correlational research and can be utilized for developing risk management plans that establish food safety guidelines for V. parahaemolyticus in Chinese shellfish.

  16. Microbial biogeography of the North Sea during summer

    NARCIS (Netherlands)

    Brandsma, J.; Martínez Martínez, J.; Slagter, H.A.; Evans, C.; Brussaard, C.P.D.

    2013-01-01

    Micro-organisms are vital for the functioning of all food webs and are the major drivers of the global biogeochemical cycles. The microbial community compositions and physicochemical conditions of the different water masses in the North Sea, a biologically productive sea on the northwestern European

  17. Lifestyle survey amongst North Sea oil workers

    Energy Technology Data Exchange (ETDEWEB)

    Horsley, Harry [RGIT Ltd., Research Unit, Aberdeen (United Kingdom); MacKenzie, I.G. [Robert Gordon Univ., School of Computer and Mathematical Sciences, Aberdeen (United Kingdom)

    1997-12-31

    Recognition is growing of the influence of the workplace on lifestyle, and its consequent effect on health. This relation between work, lifestyle and health is highly relevant to the North Sea oil and gas industry where employment often demands the adoption of, and exposure to, a lifestyle far removed from that of comparable onshore occupations. This risk factors for Coronary Heart Disease (CHD) which is the largest single cause of premature adult death in Great Britain can be classified according to those that are immodifiable (eg gender), and those that result from lifestyle choices (eg smoking, diet). The demographic profile (predominant gender, age group and nationality) of the offshore workforce is thought to place it in an inherently high risk group for CHD. Anecdotal evidence further suggests that the offshore lifestyle may expose the workforce to increased CHD risk factors, particularly in terms of diet, tobacco consumption and exercise habits. The lifestyle of offshore workers may be considered as a form of occupational hazard, comparable with recognised occupational risks. A sample of 500 offshore workers undertaking survival training were surveyed using a structured questionnaire to investigate aspects of their lifestyle. Subjects compared their smoking, dietary and exercise habits between periods onshore and offshore. Analysis of results pointed to some significant differences in lifestyle between these two periods. Additional factors such as occupation status (whether directly employed or contracted), onshore alcohol consumption, and subjects` perception of job and family satisfaction were also analysed in relation to lifestyle. Results indicate the potential benefits of health promotion intervention. Opportunities for such intervention are identified and discussed within the context of caring for an efficient utilisation of the Offshore Industry`s human resources. (Author)

  18. Daytime sea fog retrieval based on GOCI data: a case study over the Yellow Sea.

    Science.gov (United States)

    Yuan, Yibo; Qiu, Zhongfeng; Sun, Deyong; Wang, Shengqiang; Yue, Xiaoyuan

    2016-01-25

    In this paper, a new daytime sea fog detection algorithm has been developed by using Geostationary Ocean Color Imager (GOCI) data. Based on spectral analysis, differences in spectral characteristics were found over different underlying surfaces, which include land, sea, middle/high level clouds, stratus clouds and sea fog. Statistical analysis showed that the Rrc (412 nm) (Rayleigh Corrected Reflectance) of sea fog pixels is approximately 0.1-0.6. Similarly, various band combinations could be used to separate different surfaces. Therefore, three indices (SLDI, MCDI and BSI) were set to discern land/sea, middle/high level clouds and fog/stratus clouds, respectively, from which it was generally easy to extract fog pixels. The remote sensing algorithm was verified using coastal sounding data, which demonstrated that the algorithm had the ability to detect sea fog. The algorithm was then used to monitor an 8-hour sea fog event and the results were consistent with observational data from buoys data deployed near the Sheyang coast (121°E, 34°N). The goal of this study was to establish a daytime sea fog detection algorithm based on GOCI data, which shows promise for detecting fog separately from stratus.

  19. The fast expansion of Pyropia aquaculture in ;Sansha; regions should be mainly responsible for the Ulva blooms in Yellow Sea

    Science.gov (United States)

    Zhang, Jianheng; Zhao, Peng; Huo, Yuanzi; Yu, Kefeng; He, Peimin

    2017-04-01

    Massive Ulva blooms became an environmental disaster in the Yellow Sea from 2007 to 2015. In this study, field shipboard observations indicated that Ulva blooms originated in Pyropia aquaculture area, and the morphology of initial floating Ulva seaweed have the structure of rhizoid, which is similar with the attached Ulva on the Pyropia rafts. The spatial distribution of Ulva microscopic propagules in the southern Yellow Sea also supported that the blooms originated in the Pyropia aquaculture area. Besides, numerical model was used in this study, showing the origin of macroalgal blooms was traced to "Sansha" regions which accounted for almost 70% of the total Pyropia aquaculture area. We conclude that the significant biomass (4252 tons) of Ulva species on the Pyropia rafts during the harvesting season in "Sansha" regions played an important role in the early rapid development of blooms in the Yellow Sea.

  20. Seasonal and spatial changes of macrobenthic community structure and diversity in South Yellow Sea

    Science.gov (United States)

    Li, X.; Xu, Y.

    2016-02-01

    The seasonal and spatial characteristics of macrobenthic community in South Yellow Sea were studied based on the data from three voyages carried out in spring, summer and autumn, 2012. A total of 218 species were obtained, including 80 species of Polychaeta, 75 of Crustacea, 35 of Mollusca, 15 of Echinodermata and 13 of other groups. Mean abundance varied from 151.4 ind./m2 in spring to 188 ind./m2 in autumn showing an increasing trend with season and mean biomass ranged from 12.1 g/m2 in spring to 33.4 g/m2 in summer. Mean secondary productivity varied from 2.5 g(AFDW)/(m2·a) in spring to 5.7 g(AFDW)/(m2·a) in summer. Two-way ANOVA indicated that biomass were significantly different among seasons and number of species and Shannon-Weiner index had significant differences among stations. But abundance, Pielou's evenness index and average taxonomic distinctness were not significantly different among either seasons or stations. Non-parametric Kruskal-Wallis test showed significant differences of secondary productivity among tations. Two-way crossed ANOSIM indicated overall significant differences of community structure among both seasons and stations. The stations were divided into four groups in spring and five in summer and autumn through the CLUSTER and nMDS analysis. Depth was an important factor influencing distribution of macrobenthos in the South Yellow Sea.

  1. Bacterial Diversity in Submarine Groundwater along the Coasts of the Yellow Sea.

    Science.gov (United States)

    Ye, Qi; Liu, Jianan; Du, Jinzhou; Zhang, Jing

    2015-01-01

    Submarine groundwater (SGD) is one of the most significant pathways for the exchange of groundwater and/or source of nutrients, metals and carbon to the ocean, subsequently cause deleterious impacts on the coastal ecosystems. Microorganisms have been recognized as the important participators in the biogeochemical processes in the SGD. In this study, by utilizing 16S rRNA-based Illumina Miseq sequencing technology, we investigated bacterial diversity and distribution in both fresh well water and brackish recirculated porewater along the coasts in the Yellow Sea. The results showed that Actinobacteria and Betaproteobacteria, especially Comamonas spp. and Limnohabitans spp. were dominated in fresh well samples. Distinct patterns of bacterial communities were found among the porewater samples due to different locations, for examples, Cyanbacteria was the most abundant in the porewater samples far from the algal bloomed areas. The analysis of correlation between representative bacterial taxonomic groups and the contexture environmental parameters showed that fresh well water and brackish porewater might provide different nutrients to the coastal waters. Potential key bacterial groups such as Comamonas spp. may be excellent candidates for the bioremediation of the natural pollutants in the SGD. Our comprehensive understanding of bacterial diversity in the SGD along the coasts of the Yellow Sea will create a basis for designing the effective clean-up approach in-situ, and provide valuable information for the coastal management.

  2. Bacterial Diversity in Submarine Groundwater along the Coasts of the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Qi eYe

    2016-01-01

    Full Text Available Submarine groundwater (SGD is one of the most significant pathways for the exchange of groundwater and/or source of nutrients, metals and carbon to the ocean, subsequently cause deleterious impacts on the coastal ecosystems. Microorganisms have been recognized as the important participators in the biogeochemical processes in the SGD. In this study, by utilizing 16S rRNA-based Illumina Miseq sequencing technology, we investigated bacterial diversity and distribution in both fresh well water and brackish recirculated porewater along the coasts in the Yellow Sea. The results showed that Actinobacteria and Betaproteobacteria, especially Comamonas spp. and Limnohabitans spp. were dominated in fresh well samples. Distinct patterns of bacterial communities were found among the porewater samples due to different locations, for examples, Cyanbacteria was the most abundant in the porewater samples far from the algal bloomed areas. The analysis of correlation between representative bacterial taxonomic groups and the contexture environmental parameters showed that fresh well water and brackish porewater might provide different nutrients to the coastal waters. Potential key bacterial groups such as Comamonas spp. may be excellent candidates for the bioremediation of the natural pollutants in the SGD. Our comprehensive understanding of bacterial diversity in the SGD along the coasts of the Yellow Sea will create a basis for designing the effective clean-up approach in-situ, and provide valuable information for the coastal management.

  3. Ecological conversion efficiency and its influencers in twelve species of fish in the Yellow Sea Ecosystem

    Science.gov (United States)

    Tang, Qisheng; Guo, Xuewu; Sun, Yao; Zhang, Bo

    2007-09-01

    The ecological conversion efficiencies in twelve species of fish in the Yellow Sea Ecosystem, i.e., anchovy ( Engraulis japonicus), rednose anchovy ( Thrissa kammalensis), chub mackerel ( Scomber japonicus), halfbeak ( Hyporhamphus sajori), gizzard shad ( Konosirus punctatus), sand lance ( Ammodytes personatus), red seabream ( Pagrus major), black porgy ( Acanthopagrus schlegeli), black rockfish ( Sebastes schlegeli), finespot goby ( Chaeturichthys stigmatias), tiger puffer ( Takifugu rubripes), and fat greenling ( Hexagrammos otakii), were estimated through experiments conducted either in situ or in a laboratory. The ecological conversion efficiencies were significantly different among these species. As indicated, the food conversion efficiencies and the energy conversion efficiencies varied from 12.9% to 42.1% and from 12.7% to 43.0%, respectively. Water temperature and ration level are the main factors influencing the ecological conversion efficiencies of marine fish. The higher conversion efficiency of a given species in a natural ecosystem is acquired only under the moderate environment conditions. A negative relationship between ecological conversion efficiency and trophic level among ten species was observed. Such a relationship indicates that the ecological efficiency in the upper trophic levels would increase after fishing down marine food web in the Yellow Sea ecosystem.

  4. Sedimentary architecture of the Holocene mud deposit off the southern Shandong Peninsula in the Yellow Sea

    Science.gov (United States)

    Qiu, Jiandong; Liu, Jian; Xu, Hong; Zhou, Liangyong

    2018-01-01

    Newly acquired high-resolution seismic profiles reveal a nearshore and an offshore mud depocenter offthe southern Shandong Peninsula in the Yellow Sea. The nearshore depocenter is distributed in bands along the south coast of Shandong Peninsula. The offshore depocenter is part of the distal subaqueous deltaic lobe, which deposited around the southeastern tip of the Shandong Peninsula. Between the two depocenters is a linear depression. The mud deposits directly overlie the postglacial transgressive surface and can be divided into lower and upper units by the Holocene maximum flooding surface. The nearshore and offshore units display different seismic structures. The lower unit of the nearshore deposit exhibits basal onlap, whereas the upper unit is characterized by progradation. The lower and upper units of the offshore deposit display distinct acoustic features. The lower unit has low-angle aggradation with internal reflectors generally dipping seaward and truncated by the Holocene maximum flooding surface, whereas the upper unit is characterized by aggradation and progradation landward rather than seaward. Results of geochemistry analysis of QDZ03 sediments and mineral analysis of WHZK01 sediments suggest that the nearshore deposit and the lower unit of the offshore deposit are derived from the proximal coastal sediments of the Shandong Peninsula and the Huanghe (Yellow) River sediments. The upper unit of the offshore deposit is mainly Huanghe River-derived. The lower unit of the mud deposit represents a post-glacial transgressive system tract according to dates of core QDZ03, and the upper unit represents a highstand system tract from middle Holocene to the present. These results will be of great significance to further understanding of the transportation of the Huanghe River sediments into the Yellow Sea and the spatial distribution of the subaqueous delta.

  5. SSU rDNA sequence diversity and seasonally differentiated distribution of nanoplanktonic ciliates in neritic Bohai and Yellow Seas as revealed by T-RFLP.

    Directory of Open Access Journals (Sweden)

    Jun Dong

    Full Text Available Nanociliates have been frequently found to be important players in the marine microbial loop, however, little is known about their diversity and distribution in coastal ecosystems. We investigated the molecular diversity and distribution patterns of nanoplanktonic oligotrich and choreotrich (OC ciliates in surface water of three neritic basins of northern China, the South Yellow Sea (SYS, North Yellow Sea (NYS, and Bohai Sea (BS in June and November 2011. SSU rRNA gene clone libraries generated from three summertime samples (sites B38, B4 and H8 were analyzed and revealed a large novel ribotype diversity, of which many were low-abundant phylotypes belonging to the subclass Oligotrichia, but divergent from described morphospecies. Based on the data of terminal-restriction fragment length polymorphism (T-RFLP analysis of all 35 samples, we found that the T-RF richness was generally higher in the SYS than in the BS, and negatively correlated with the molar ratio of P to Si. Overall, multidimensional scaling and permutational multivariate analysis of variance of the community turnover demonstrated a distinct seasonal pattern but no basin-to-basin differentiation across all samples. Nevertheless, significant community differences among basins were recognized in the winter dataset. Mantel tests showed that the environmental factors, P:Si ratio, water temperature and concentration of dissolved oxygen (DO, determined the community across all samples. However, both biogeographic distance and environment shaped the community in winter, with DO being the most important physicochemical factor. Our results indicate that the stoichiometric ratio of P:Si is a key factor, through which the phytoplankton community may be shaped, resulting in a cascade effect on the diversity and community composition of OC nanociliates in the N-rich, Si-limited coastal surface waters, and that the Yellow Sea Warm Current drives the nanociliate community, and possibly the

  6. SSU rDNA sequence diversity and seasonally differentiated distribution of nanoplanktonic ciliates in neritic Bohai and Yellow Seas as revealed by T-RFLP.

    Science.gov (United States)

    Dong, Jun; Shi, Fei; Li, Han; Zhang, Xiaoming; Hu, Xiaozhong; Gong, Jun

    2014-01-01

    Nanociliates have been frequently found to be important players in the marine microbial loop, however, little is known about their diversity and distribution in coastal ecosystems. We investigated the molecular diversity and distribution patterns of nanoplanktonic oligotrich and choreotrich (OC) ciliates in surface water of three neritic basins of northern China, the South Yellow Sea (SYS), North Yellow Sea (NYS), and Bohai Sea (BS) in June and November 2011. SSU rRNA gene clone libraries generated from three summertime samples (sites B38, B4 and H8) were analyzed and revealed a large novel ribotype diversity, of which many were low-abundant phylotypes belonging to the subclass Oligotrichia, but divergent from described morphospecies. Based on the data of terminal-restriction fragment length polymorphism (T-RFLP) analysis of all 35 samples, we found that the T-RF richness was generally higher in the SYS than in the BS, and negatively correlated with the molar ratio of P to Si. Overall, multidimensional scaling and permutational multivariate analysis of variance of the community turnover demonstrated a distinct seasonal pattern but no basin-to-basin differentiation across all samples. Nevertheless, significant community differences among basins were recognized in the winter dataset. Mantel tests showed that the environmental factors, P:Si ratio, water temperature and concentration of dissolved oxygen (DO), determined the community across all samples. However, both biogeographic distance and environment shaped the community in winter, with DO being the most important physicochemical factor. Our results indicate that the stoichiometric ratio of P:Si is a key factor, through which the phytoplankton community may be shaped, resulting in a cascade effect on the diversity and community composition of OC nanociliates in the N-rich, Si-limited coastal surface waters, and that the Yellow Sea Warm Current drives the nanociliate community, and possibly the microbial food webs

  7. The dissolved yellow substance and the shades of blue in the Mediterranean Sea

    Science.gov (United States)

    Morel, A.; Gentili, B.

    2009-11-01

    When the nominal algorithms commonly in use in Space Agencies are applied to satellite Ocean Color data, the retrieved chlorophyll concentrations in the Mediterranean Sea are recurrently notable overestimates of the field values. Accordingly, several regionally tuned algorithms have been proposed in the past to correct for this deviation. Actually, the blueness of the Mediterranean waters is not as deep as expected from the actual (low) chlorophyll content, and the modified algorithms account for this peculiarity. Among the possible causes for such a deviation, an excessive amount of yellow substance (or of chromophoric dissolved organic matter, CDOM) has been frequently cited. This conjecture is presently tested, by using a new technique simply based on the simultaneous consideration of marine reflectance determined at four spectral bands, namely at 412, 443, 490, and 555 nm, available on the NASA-SeaWiFS sensor (Sea-viewing Wide Field-of-view Sensor). It results from this test that the concentration in yellow colored material (quantified as ay, the absorption coefficient of this material at 443 nm) is about twice that one observed in the nearby Atlantic Ocean at the same latitude. There is a strong seasonal signal, with maximal ay values in late fall and winter, an abrupt decrease beginning in spring, and then a flat minimum during the summer months, which plausibly results from the intense photo-bleaching process favored by the high level of sunshine in these areas. Systematically, the ay values, reproducible from year to year, are higher in the western basin compared with those in the eastern basin (by about 50%). The relative importance of the river discharges into this semi-enclosed sea, as well as the winter deep vertical mixing occurring in the northern parts of the basins may explain the high yellow substance background. The regionally tuned [Chl] algorithms, actually reflect the presence of an excess of CDOM with respect to its standard (Chl

  8. The importance of North Sea gas to European energy supply

    International Nuclear Information System (INIS)

    Probert, R.

    1992-01-01

    Natural gas can, of course, be transported over very long distances but, because of the economics of gas transmission, its impact is most often local. This has certainly been the case with North Sea gas, which has clearly contributed significantly to European energy supply and will continue to do so for some time to come. The historical importance of the discovery of gas in the North Sea has been that it has enabled natural gas industries to grow rapidly in North West Europe. Without North Sea gas and Dutch gas it is difficult to see how town gas would have been replaced in North West Europe. Certainly, a much smaller natural gas industry would have emerged. North Sea gas has inevitably had the greatest impact on gas markets in the countries of the European Community and this will remain the case in future. Nevertheless, it is inevitable that gas will, in future, flow across more national boundaries than in the past, and that North Sea gas will have an important part to play in meeting the Central European demand for competitively priced, secure supplies. This paper discusses the United Kingdom market for gas and future demand both in the United Kingdom and more widely in Europe. An examination of the availability of gas supplies from the North Sea suggests that it is unlikely that there will be a surplus of gas for export from the United Kingdom continental shelf. Norway will remain the main source of exports, with the Netherlands also in a strong position. Transportation and political aspects are also considered. (author)

  9. North Sea oil and gas: a geographical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, K

    1976-01-01

    Only ten years after the first rig moved into position, British oil has been piped ashore from the North Sea and, by 1980, will be making a substantial contribution to UK energy supplies. The discovery of natural gas in 1967--for initially gas was the primary objective--has transformed the gas supply so that 90% of the UK's needs already come from the North Sea. The speed and concentration of exploration pinpoints the vital importance of this new energy source. Until now the major oil 'pipeline' in the world has been led between the Middle East and Western Europe, so this new energy source has far reaching implications, both political and economic. Keith Chapman examines these implications starting from events in the North Sea itself; the geological background, agreement on the division of the North Sea, relations between oil companies, and government embodied in offshore mining legislation. The latter part of the book concentrates on the onshore repercussions of offshore activities; how North Sea oil fits into the international oil system, the various options open for its utilisation, the attitude of the EEC towards Scottish-based resources, government policy for the North coast of Scotland--an area which planners classed as ''peripheral'' but which must now accommodate extensive support facilities and service industries for the oil sites. There is also the question of relations between national and commercial interests--government versus the giant multi-national companies which took the initial gamble in the North Sea and are now responsible for the development of a resource vital to the economic well-being of Western Europe.

  10. Sea Surface Temperature (14 KM North America)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Product shows local sea surface temperatures (degrees C). It is a composite gridded-image derived from 8-km resolution SST Observations. It is generated every 48...

  11. The dissolved yellow substance and the shades of blue in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    B. Gentili

    2009-11-01

    Full Text Available When the nominal algorithms commonly in use in Space Agencies are applied to satellite Ocean Color data, the retrieved chlorophyll concentrations in the Mediterranean Sea are recurrently notable overestimates of the field values. Accordingly, several regionally tuned algorithms have been proposed in the past to correct for this deviation. Actually, the blueness of the Mediterranean waters is not as deep as expected from the actual (low chlorophyll content, and the modified algorithms account for this peculiarity. Among the possible causes for such a deviation, an excessive amount of yellow substance (or of chromophoric dissolved organic matter, CDOM has been frequently cited. This conjecture is presently tested, by using a new technique simply based on the simultaneous consideration of marine reflectance determined at four spectral bands, namely at 412, 443, 490, and 555 nm, available on the NASA-SeaWiFS sensor (Sea–viewing Wide Field-of-view Sensor. It results from this test that the concentration in yellow colored material (quantified as ay, the absorption coefficient of this material at 443 nm is about twice that one observed in the nearby Atlantic Ocean at the same latitude. There is a strong seasonal signal, with maximal ay values in late fall and winter, an abrupt decrease beginning in spring, and then a flat minimum during the summer months, which plausibly results from the intense photo-bleaching process favored by the high level of sunshine in these areas. Systematically, the ay values, reproducible from year to year, are higher in the western basin compared with those in the eastern basin (by about 50%. The relative importance of the river discharges into this semi-enclosed sea, as well as the winter deep vertical mixing occurring in the northern parts of the basins may explain the high yellow substance background. The regionally tuned [Chl] algorithms, actually reflect the

  12. Situation in the sea area between the North Sea and the Baltic Sea. Situationen i havsomraadet mellan Nordsjoen och Oestersjoen

    Energy Technology Data Exchange (ETDEWEB)

    Dybern, B.I.; Soederstroem, J.; Thorell, L.

    1984-01-01

    Due to the special topographical and hydrological features the seas surrounding Sweden are very sensitive to both natural changes and changes caused by man. The sea area between the North Sea and the Baltic Sea has come into focus during the last few decades due to problems with pollution and its impact on the ecosystems and to overfishing of some commer- cially important species. In order to elucidate the present situation from the Swedish viewpoint, the National Board of Fisheries, the National Environment Protection Board and the County Council of the County Goeteborg and Bohyslaen arranged a Symposium on the Situation in the Sea Area between the North Sea and the Baltic Sea in Goeteborg, 14-16 March, 1983. This volume contains lectures given at that Symposium. In most cases there are English summaries and English translations of texts to figures and tables.

  13. The importance of North Sea oil to European energy supply

    International Nuclear Information System (INIS)

    Bauw, R. De

    1992-01-01

    There is no doubt about the importance of North Sea oil to the energy supply of the European Community. One might however be used to it and forget about the nature and the size of its impact on our economies. Firstly, this paper intends to estimate this impact - past, present and future. Secondly, a more qualitative approach will explore possible consequences of the implementation of the internal market for North Sea oil. Thirdly, the assistance given by the Community to innovative technologies which enabled North Sea oil to contribute, under better economic conditions and within a safer environment, to our supply is recalled. And finally, some remarks on energy policy form an EC perspective, are offered. (author)

  14. Risk assessment for yellow fever in western and North-Western provinces of Zambia

    Directory of Open Access Journals (Sweden)

    Olusegun A Babaniyi

    2015-01-01

    Full Text Available Background: North-Western and Western provinces of Zambia were reclassified as low-risk areas for yellow fever (YF. However, the current potential for YF transmission in these areas is unclear. Aims: To determine the current potential risk of YF infection. Setting and Design: A cross sectional study was conducted in North-Western and Western provinces of Zambia. Materials and Methods: Samples were tested for both YF virus-specific IgG and IgM antibodies by the ELISA and YF virus confirmation was done using Plaque Reduction Neutralization Test. The samples were also tested for IgG and IgM antibodies against other flaviviruses. Results: Out of the 3625 respondents who participated in the survey, 46.7% were males and 9.4% were aged less than 5 years. Overall, 58.1% of the participants slept under an impregnated insecticide-treated net and 20.6% reported indoor residual spraying of insecticides. A total of 616 (17.0% samples were presumptive YF positive. The prevalence for YF was 0.3% for long-term infection and 0.2% for recent YF infection. None of the YF confirmed cases had received YF vaccine. Prevalence rates for other flaviviruses were 149 (4.1% for Dengue, 370 (10.2% for West Nile and 217 (6.0% for Zika. Conclusion: There is evidence of past and recent infection of YF in both provinces. Hence, they are at a low risk for YF infection. Yellow fever vaccination should be included in the EPI program in the two provinces and strengthen surveillance with laboratory confirmation.

  15. Dynamic and static elastic moduli of North Sea and deep sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke

    2001-01-01

    We have established an empirical relationship between the dynamic and the static mechanical properties of North Sea and deep sea chalk for a large porosity interval with respect to porosity, effective stress history and textural composition. The chalk investigated is from the Tor and Hod Formatio...

  16. Mechanisms controlling the air–sea CO2 flux in the North Sea

    NARCIS (Netherlands)

    Prowe, A.E.F.; Thomas, Helmuth; Pätsch, Johannes; Kühn, Wilfried; Bozec, Yann; Schiettecatte, Laure-Sophie; Borges, Alberto V.; Baar, Hein J.W. de; Paetsch, J; Kuehn, W

    2009-01-01

    The mechanisms driving the air–sea exchange of carbon dioxide (CO2) in the North Sea are investigated using the three-dimensional coupled physical–biogeochemical model ECOHAM (ECOlogical-model, HAMburg). We validate our simulations using field data for the years 2001–2002 and identify the controls

  17. Locked chromophore analogs reveal that photoactive yellow protein regulates biofilm formation in the deep sea bacterium Idiomarina loihiensis

    NARCIS (Netherlands)

    van der Horst, M.A.; Stalcup, T.P.; Kaledhonkar, S.; Kumauchi, M.; Hara, M.; Xie, A.; Hellingwerf, K.J.; Hoff, W.D.

    2009-01-01

    Idiomarina loihiensis is a heterotrophic deep sea bacterium with no known photobiology. We show that light suppresses biofilm formation in this organism. The genome of I. loihiensis encodes a single photoreceptor protein: a homologue of photoactive yellow protein (PYP), a blue light receptor with

  18. Shifting climate, altered niche, and a dynamic conservation strategy for yellow-cedar in the North Pacific coastal rainforest

    Science.gov (United States)

    Paul E. Hennon; David V. D' Amore; Paul G. Schaberg; Dustin T. Wittwer; Colin S. Shanley

    2012-01-01

    The extensive mortality of yellow-cedar along more than 1000 kilometers of the northern Pacific coast of North America serves as a leading example of climate effects on a forest tree species. In this article, we document our approaches to resolving the causes of tree death, which we explain as a cascade of interacting topographic, forest-structure, and microclimate...

  19. Terrestrial dissolved organic matter distribution in the North Sea.

    Science.gov (United States)

    Painter, Stuart C; Lapworth, Dan J; Woodward, E Malcolm S; Kroeger, Silke; Evans, Chris D; Mayor, Daniel J; Sanders, Richard J

    2018-07-15

    The flow of terrestrial carbon to rivers and inland waters is a major term in the global carbon cycle. The organic fraction of this flux may be buried, remineralized or ultimately stored in the deep ocean. The latter can only occur if terrestrial organic carbon can pass through the coastal and estuarine filter, a process of unknown efficiency. Here, data are presented on the spatial distribution of terrestrial fluorescent and chromophoric dissolved organic matter (FDOM and CDOM, respectively) throughout the North Sea, which receives organic matter from multiple distinct sources. We use FDOM and CDOM as proxies for terrestrial dissolved organic matter (tDOM) to test the hypothesis that tDOM is quantitatively transferred through the North Sea to the open North Atlantic Ocean. Excitation emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) revealed a single terrestrial humic-like class of compounds whose distribution was restricted to the coastal margins and, via an inverse salinity relationship, to major riverine inputs. Two distinct sources of fluorescent humic-like material were observed associated with the combined outflows of the Rhine, Weser and Elbe rivers in the south-eastern North Sea and the Baltic Sea outflow to the eastern central North Sea. The flux of tDOM from the North Sea to the Atlantic Ocean appears insignificant, although tDOM export may occur through Norwegian coastal waters unsampled in our study. Our analysis suggests that the bulk of tDOM exported from the Northwest European and Scandinavian landmasses is buried or remineralized internally, with potential losses to the atmosphere. This interpretation implies that the residence time in estuarine and coastal systems exerts an important control over the fate of tDOM and needs to be considered when evaluating the role of terrestrial carbon losses in the global carbon cycle. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. 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.

  1. Radioactive inputs to the North Sea and the Channel

    International Nuclear Information System (INIS)

    1984-01-01

    The subject is covered in sections: introduction (radioactivity; radioisotopes; discharges from nuclear establishments); data sources (statutory requirements); sources of liquid radioactive waste (figure showing location of principal sources of radioactive discharges; tables listing principal discharges by activity and by nature of radioisotope); Central Electricity Generating Board nuclear power stations; research and industrial establishments; Ministy of Defence establishments; other UK inputs of radioactive waste; total inputs to the North Sea and the Channel (direct inputs; river inputs; adjacent sea areas); conclusions. (U.K.)

  2. Emissions from oil platforms in the North Sea

    International Nuclear Information System (INIS)

    Kanowski, S.

    1991-01-01

    When oil and gas are extracted from below the sea bed, emissions generally occur drilling and extraction and when offshore installations are abandoned. The sources of such emissions are the drilling fluids which contain many chemicals, cuttings, extracted hydrocarbons, substances released as a result of accidents, and the improper disposal of substances used in drilling and production. Platforms are regarded as land-based installations. Regulations to limit emissions have been put into effect within the scope of the Paris Convention on the protection of the North Sea and the North-East Atlantic. (orig.) [de

  3. Regionalization of climate model results for the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kauker, F.

    1999-07-01

    A dynamical downscaling is presented that allows an estimation of potential effects of climate change on the North Sea. Therefore, the ocean general circulation model OPYC is adapted for application on a shelf by adding a lateral boundary formulation and a tide model. In this set-up the model is forced, first, with data from the ECMWF reanalysis for model validation and the study of the natural variability, and, second, with data from climate change experiments to estimate the effects of climate change on the North Sea. (orig.)

  4. Tracing the origin of Pb using stable Pb isotopes in surface sediments along the Korean Yellow Sea coast

    Science.gov (United States)

    Park, Jong-Kyu; Choi, Man-Sik; Song, Yunho; Lim, Dhong-Il

    2017-06-01

    To investigate the factors controlling lead (Pb) concentration and identify the sources of Pb in Yellow Sea sediments along the Korean coast, the concentration of Pb and Pb isotopes in 87 surface and 6 core sediment samples were analyzed. The 1 M HCl leached Pb concentrations had a similar geographic distribution to those of fine-grained sediments, while the distribution of residual Pb concentrations resembled that of coarse-grained sediments. Leached Pb was presumed to be associated with manganese (Mn) oxide and iron (Fe) oxy/hydroxide, while residual Pb was associated with potassium (K)-feldspar, based on good linear relationships between the leached Pb and the Fe/Mn concentrations, and the residual Pb and K concentrations. Based on a ratio-ratio plot with three isotopes (207Pb/206Pb and 208Pb/206Pb) and the geographic location of each sediment, sediments were categorized into two groups of samples as group1 and group2. Group 1 sediments, which were distributed in Gyeonggi Bay and offshore (north of 36.5°N), were determined to be a mixture of anthropogenic and natural Pb originating from the Han River, based on a 208Pb/206Pb against a Cs/Pbleached mixing plot of core and surface sediments. Group 2 sediments, which were distributed in the south of 36.5°N, also showed a two endmembers mixing relationship between materials from the Geum River and offshore materials, which had very different Pb concentrations and isotope ratios. Based on the isotopes and their concentrations in core and surface sediments, this mixing relationship was interpreted as materials from two geographically different origins being mixed, rather than anthropogenic or natural mixing of materials with the same origin. Therefore, the relative percentage of materials supplied from the Geum River was calculated using a two endmembers mixing model and estimated to be as much as about 50% at 35°N. The spatial distribution of materials derived from the Geum River represented that of fine

  5. DNA barcode assessment of Ceramiales (Rhodophyta) in the intertidal zone of the northwestern Yellow Sea

    Science.gov (United States)

    Du, Guoying; Wu, Feifei; Guo, Hao; Xue, Hongfan; Mao, Yunxiang

    2015-05-01

    A total of 142 specimens of Ceramiales (Rhodophyta) were collected each month from October 2011 to November 2012 in the intertidal zone of the northwestern Yellow Sea. These specimens covered 21 species, 14 genera, and four families. Cluster analyses show that the specimens had a high diversity for the three DNA markers, namely, partial large subunit rRNA gene (LSU), universal plastid amplicon (UPA), and partial mitochondrial cytochrome c oxidase subunit I gene (COI). No intraspecific divergence was found in our collection for these markers, except for a 1-3 bp divergence in the COI of Ceramium kondoi, Symphyocladia latiuscula, and Neosiphonia japonica. Because short DNA markers were used, the phylogenetic relationships of higher taxonomic levels were hard to evaluate with poor branch support. More than half species of our collection failed to find their matched sequences owing to shortage information of DNA barcodes for macroalgae in GenBank or BOLD (Barcode of Life Data) Systems. Three specimens were presumed as Heterosiphonia crispella by cluster analyses on DNA barcodes assisted by morphological identification, which was the first record in the investigated area, implying that it might be a cryptic or invasive species in the coastal area of northwestern Yellow Sea. In the neighbor-joining trees of all three DNA markers, Heterosiphonia japonica converged with Dasya spp. and was distant from the other Heterosiphonia spp., implying that H. japonica had affinities to the genus Dasya. The LSU and UPA markers amplified and sequenced easier than the COI marker across the Ceramiales species, but the COI had a higher ability to discriminate between species.

  6. Monthly CO2 at A4HDYD station in a productive shallow marginal sea (Yellow Sea) with a seasonal thermocline: Controlling processes

    Science.gov (United States)

    Xu, Xuemei; Zang, Kunpeng; Zhao, Huade; Zheng, Nan; Huo, Cheng; Wang, Juying

    2016-07-01

    Based upon 21 field surveys conducted from March 2011 to November 2013, monthly variation of carbon dioxide partial pressure (pCO2) and other carbon system parameters were investigated for the first time (to our knowledge) at A4HDYD station (38°40‧N, 122°10‧E) located in the North Yellow Sea, a region with a seasonal thermocline. Surface pCO2 was undersaturated from March to May and nearly in equilibrium with the atmosphere from June to August. During September and November, pCO2 declined to a lower level than that from June to August, but reached the highest level in December. In contrast, pCO2 declined to atmospheric CO2 levels in February. Overall, the study area was a net CO2 sink at a rate of 0.85 ± 0.59 mol C m- 2 yr- 1. The underlying processes governing the variation of pCO2 were also examined. In general, temperature had an important influence on the monthly variation of pCO2, but its effect was counterbalanced by biological production in spring and vertical mixing in early winter. Our study indicated that dynamic mechanism studies based on high temporal resolution observations are urgently needed to understand the complexity of the carbon cycle and detect biogeochemical changes or ecosystem responses to climate change on continental margins.

  7. Interannual variability of north Atlantic Sea surface temperatures

    International Nuclear Information System (INIS)

    Bhatt, U.S.; Battisiti, D.S.; Alexander, M.A.

    1994-01-01

    In the midlatitude north Atlantic Ocean the pattern of sea surface temperature anomalies (ssta) is characterized by a north-south dipole. Bjerknes was the first to propose that the banded structure was associated with the interannual variability. Recently, these patterns have been studied more extensively. In this study the quantitative aspects of these patterns are examined through the use of a mixed-layer model (MLM)

  8. Regionalization of climate model results for the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kauker, F. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany); Storch, H. von [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    2000-07-01

    A dynamical downscaling for the North Sea is presented. The numerical model used for the study is the coupled ice-ocean model OPYC. In a hindcast of the years 1979 to 1993 it was forced with atmospheric forcing of the ECMWF reanalysis. The models capability in simulating the observed mean state and variability in the North Sea is demonstrated by the hindcast. Two time scale ranges, from weekly to seasonal and the longer-than-seasonal time scales are investigated. Shorter time scales, for storm surges, are not captured by the model formulation. The main modes of variability of sea level, sea-surface circulation, sea-surface temperature, and sea-surface salinity are described and connections to atmospheric phenomena, like the NAO, are discussed. T106 ''time-slice'' simulations with a ''2 x CO{sub 2}'' horizon are used to estimate the effects of a changing climate on the shelf sea ''North Sea''. The ''2 x CO{sub 2}'' changes in the surface forcing are accompanied by changes in the lateral oceanic boundary conditions taken from a global coupled climate model. For ''2 x CO{sub 2}'' the time mean sea level increases up to 25 cm in the German Bight in the winter, where 15 cm are due to the surface forcing and 10 cm due to thermal expansion. This change is compared to the ''natural'' variability as simulated in the ECMWF integration and found to be not outside the range spanned by it. The variability of sea level on the weekly-to-seasonal time-scales is significantly reduced in the scenario integration. The variability on the longer-than-seasonal time-scales in the control and scenario runs is much smaller then in the ECMWF integration. This is traced back to the use of ''time-slice'' experiments. Discriminating between locally forced changes and changes induced at the lateral oceanic boundaries of the model in the circulation and

  9. Sources of polycyclic aromatic hydrocarbons to sediments of the Bohai and Yellow Seas in East Asia

    Science.gov (United States)

    Lin, Tian; Hu, Limin; Guo, Zhigang; Qin, Yanwen; Yang, Zuosheng; Zhang, Gan; Zheng, Mei

    2011-12-01

    The coasts of Bohai Sea (BS) and Yellow Sea (YS) in China support almost one-quarter of its population and provide more than one-third of the national GDP. BS and YS are downwind of the Asian continental outflow in spring and winter as influenced by the East Asian monsoon. This makes the two seas important sinks of land-based pollutants associated with the Asian continental outflow. The sixteen U.S. EPA proposed priority polycyclic aromatic hydrocarbons (PAHs) in 130 surface sediment samples collected from BS and YS were measured. Combined with our previous PAH data of 90 PM2.5 samples from the upwind areas, the sources of the PAHs in BS and YS were apportioned using positive matrix factorization (PMF) modeling. Four sources were identified: petroleum residue, vehicular emissions, coal combustion and biomass burning. Petroleum residue was the dominant contributor of PAHs in the coast of the Bohai Bay probably due to Haihe River runoff, oil leakage from ships and offshore oil fields. The contribution of vehicular emissions in BS was higher than that in YS, and the reverse was true for coal combustion and biomass burning. This difference in the source patterns in the sediments of the two seas could be attributed to the different PAH emission features of the upwind area related to demographic and economic conditions, as well as the marine geography. The ratios of selected 4-6 ring PAHs in the sediments compared well with those of the PM2.5 of the upwind areas, implicating that the particle phase PAHs in the atmosphere play an important role in the source to sink process of the pyrogenic PAHs in the region.

  10. Distribution and sea-to-air flux of isoprene in the East China Sea and the South Yellow Sea during summer.

    Science.gov (United States)

    Li, Jian-Long; Zhang, Hong-Hai; Yang, Gui-Peng

    2017-07-01

    Spatial distribution and sea-to-air flux of isoprene in the East China Sea and the South Yellow Sea in July 2013 were investigated. This study is the first to report the concentrations of isoprene in the China marginal seas. Isoprene concentrations in the surface seawater during summer ranged from 32.46 to 173.5 pM, with an average of 83.62 ± 29.22 pM. Distribution of isoprene in the study area was influenced by the diluted water from the Yangtze River, which stimulated higher in-situ phytoplankton production of isoprene rather than direct freshwater input. Variations in isoprene concentrations were found to be diurnal, with high values observed during daytime. A significant correlation was observed between isoprene and chlorophyll a in the study area. Relatively higher isoprene concentrations were recorded at stations where the phytoplankton biomass was dominated by Chaetoceros, Skeletonema, Pennate-nitzschia, and Thalassiosira. Positive correlation was observed between isoprene and methyl iodide. In addition, sea-to-air fluxes of isoprene approximately ranged from 22.17 nmol m -2  d -1 -537.2 nmol m -2  d -1 , with an average of 161.5 ± 133.3 nmol m -2  d -1 . These results indicate that the coastal and shelf areas may be important sources of atmospheric isoprene. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Sea Surface Temperature Climate Data Record for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Høyer, Jacob L.; Karagali, Ioanna

    2016-01-01

    A 30-yr climate data record (CDR) of sea surface temperature (SST) has been produced with daily gap-free analysis fields for the North Sea and the Baltic Sea region from 1982 to 2012 by combining the Pathfinder AVHRR satellite data record with the Along-Track Scanning Radiometer (ATSR) Reprocessing...... for Climate (ARC) dataset and with in situ observations. A dynamical bias correction scheme adjusts the Pathfinder observations toward the ARC and in situ observations. Largest Pathfinder-ARC differences are found in the summer months, when the Pathfinder observations are up to 0.4 °C colder than the ARC...... observations on average. Validation against independent in situ observations shows a very stable performance of the data record, with a mean difference of -0.06 °C compared to moored buoys and a 0.46 °C standard deviation of the differences. The mean annual biases of the SST CDR are small for all years...

  12. Regulation of CO2 Air Sea Fluxes by Sediments in the North Sea

    Science.gov (United States)

    Burt, William; Thomas, Helmuth; Hagens, Mathilde; Brenner, Heiko; Pätsch, Johannes; Clargo, Nicola; Salt, Lesley

    2016-04-01

    A multi-tracer approach is applied to assess the impact of boundary fluxes (e.g. benthic input from sediments or lateral inputs from the coastline) on the acid-base buffering capacity, and overall biogeochemistry, of the North Sea. Analyses of both basin-wide observations in the North Sea and transects through tidal basins at the North-Frisian coastline, reveal that surface distributions of the δ13C signature of dissolved inorganic carbon (DIC) are predominantly controlled by a balance between biological production and respiration. In particular, variability in metabolic DIC throughout stations in the well-mixed southern North Sea indicates the presence of an external carbon source, which is traced to the European continental coastline using naturally-occurring radium isotopes (224Ra and 228Ra). 228Ra is also shown to be a highly effective tracer of North Sea total alkalinity (AT) compared to the more conventional use of salinity. Coastal inputs of metabolic DIC and AT are calculated on a basin-wide scale, and ratios of these inputs suggest denitrification as a primary metabolic pathway for their formation. The AT input paralleling the metabolic DIC release prevents a significant decline in pH as compared to aerobic (i.e. unbuffered) release of metabolic DIC. Finally, long-term pH trends mimic those of riverine nitrate loading, highlighting the importance of coastal AT production via denitrification in regulating pH in the southern North Sea.

  13. Loss of sea ice during winter north of Svalbard

    Directory of Open Access Journals (Sweden)

    Ingrid H. Onarheim

    2014-06-01

    Full Text Available Sea ice loss in the Arctic Ocean has up to now been strongest during summer. In contrast, the sea ice concentration north of Svalbard has experienced a larger decline during winter since 1979. The trend in winter ice area loss is close to 10% per decade, and concurrent with a 0.3°C per decade warming of the Atlantic Water entering the Arctic Ocean in this region. Simultaneously, there has been a 2°C per decade warming of winter mean surface air temperature north of Svalbard, which is 20–45% higher than observations on the west coast. Generally, the ice edge north of Svalbard has retreated towards the northeast, along the Atlantic Water pathway. By making reasonable assumptions about the Atlantic Water volume and associated heat transport, we show that the extra oceanic heat brought into the region is likely to have caused the sea ice loss. The reduced sea ice cover leads to more oceanic heat transferred to the atmosphere, suggesting that part of the atmospheric warming is driven by larger open water area. In contrast to significant trends in sea ice concentration, Atlantic Water temperature and air temperature, there is no significant temporal trend in the local winds. Thus, winds have not caused the long-term warming or sea ice loss. However, the dominant winds transport sea ice from the Arctic Ocean into the region north of Svalbard, and the local wind has influence on the year-to-year variability of the ice concentration, which correlates with surface air temperatures, ocean temperatures, as well as the local wind.

  14. Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary.

    Science.gov (United States)

    Zhao, Zhen; Tang, Jianhui; Mi, Lijie; Tian, Chongguo; Zhong, Guangcai; Zhang, Gan; Wang, Shaorui; Li, Qilu; Ebinghaus, Ralf; Xie, Zhiyong; Sun, Hongwen

    2017-12-01

    Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral ∑PFASs were within the range of 76-551pg/m 3 . Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral ∑PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral ∑PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition were simulated for neutral PFASs, and neutral ∑PFASs fluxes varied from 0.37 to 2.3pg/m 2 /s. In the dissolved phase of the surface water, concentrations of ionic ∑PFASs ranged from 1.6 to 118ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic ∑PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic ∑PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Estimating the effective nitrogen import: An example for the North Sea-Baltic Sea boundary

    Science.gov (United States)

    Radtke, H.; Maar, M.

    2016-10-01

    Semienclosed water bodies such as the Baltic Sea are prone to eutrophication problems. If local nutrient abatement measures are taken to tackle these problems, their success may be limited if a strong nutrient exchange with the adjacent waters exists. The quantification of this exchange is therefore essential to estimate its impact on the ecosystem status. At the example of the Baltic Sea and the North Sea, we illustrate that neither gross transports nor net transports of nutrients have a strong informative value in this context. Instead, we define an "effective import" as the import of nutrients which have not been inside the Baltic Sea before and estimate it in an ecological model with a nutrient-tagging technique. This effective import of bioreactive nitrogen from the Skagerrak to the Kattegat amounts to 103 kt/yr; from Kattegat to Belt Sea it is 54 kt/yr. The nitrogen exchange is therefore 30% stronger than other estimates, e.g., based on import in the deep water, suggest. An isolated view on the Baltic Sea and the North Sea in terms of eutrophication, as it is practiced in management today, is therefore questionable. Nitrogen imported from the North Sea typically spreads eastward up to the Bornholm Basin but can be transported into the deep waters of the Gotland Basin during Major Baltic Inflows in a significant amount.

  16. Sediment volume in the north polar sand seas of Mars

    International Nuclear Information System (INIS)

    Lancaster, N.; Greeley, R.

    1990-01-01

    Data from studies of the cross-sectional area of terrestrial transverse dunes have been combined with maps of dune morphometry derived from Viking orbiter images to generate new estimates of sediment thickness and dune sediment volume in the north polar sand seas of Mars. A relationship between dune spacing and equivalent sediment thickness (EST) was developed from field data on Namibian and North American dunes and was applied to data on dune spacing and dune cover measured on Viking orbiter images to generate maps of dune sediment thickness for Martian north polar sand seas. There are four major sand seas in the north polar region of Mars, covering an area of 6.8 x 10 5 km 2 . Equivalent sediment thickness ranges between 0.5 and 6.1 m with a mean of 1.8 m. The sand seas contain a total of 1158 km 3 of dune sediment, which may have been derived by erosion of polar layered deposits and concentrated in its present location by winds that change direction seasonally

  17. Arctic fox (Alopex lagopus) from the North Sea

    NARCIS (Netherlands)

    Langeveld, Bram W.; Mol, Dick; van der Plicht, Hans

    2018-01-01

    The first record of arctic fox Alopex lagopus (Linnaeus, 1758) from the Eurogeul area (North Sea) is reported based on a distal humerus fragment collected by private collectors from dredged sediments on ‘De Zandmotor’. It was radiocarbon dated to 29,900 + 550/- 490 BP (GrA-69520), which is younger

  18. The European anchovy (Engraulis encrasicolus) increase in the North Sea

    NARCIS (Netherlands)

    Raab, K.E.

    2013-01-01

    Small pelagic fish such as anchovy are of high socio-economic importance worldwide. They are known for strong fluctuations in abundance, for which the mechanisms are not always understood. European anchovy (Engraulis encrasicolus) increased its population in the North Sea starting in

  19. Anchovy Engraulis encrasicolus diet in the North and Baltic Seas

    NARCIS (Netherlands)

    Raab, K.E.; Nagelkerke, L.A.J.; Boerée, L.A.J.; Rijnsdorp, A.D.; Temming, A.; Dickey-Collas, M.

    2011-01-01

    The diet of anchovy (Engraulis encrasicolus) in the North and Baltic Seas was studied using stomach analysis from four sampling events in different areas. Zooplanktivory was confirmed; the most frequent prey items (in over 40% of stomachs) were copepods, malacostracan larvae and fish larvae. In the

  20. A southern North Sea Miocene dinoflagellate cyst zonation

    NARCIS (Netherlands)

    Munsterman, D.K.; Brinkhuis, H.

    2004-01-01

    An integrated stratigraphical analysis emphasizing organic-walled dinoflagellate cyst (dinocyst) distribution has been carried out on multiple boreholes penetrating the Miocene in the subsurface of the Netherlands (southern North Sea Basin). The bulk of the investigated successions is attributed to

  1. Sleep and Alertness in North Sea Helicopter Operations

    NARCIS (Netherlands)

    Simons, M.; Wilschut, E.S.; Valk, P.J.L.

    2011-01-01

    Introduction : Dutch North Sea helicopter operations are characterized by multiple sector flights to offshore platforms under difficult environmental conditions. In the context of a Ministry of Transport program to improve safety levels of helicopter operations, we assessed effects of pre-duty

  2. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind

  3. The Potential for Wave Energy in the North Sea

    DEFF Research Database (Denmark)

    Sørensen, H. C.; Chozas, Julia Fernandez

    2010-01-01

    The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost ...... is resulting in a prediction of a yearly production of 23TWh; the latter is estimating a yearly production of 77TWh. This equals to 6% of the electricity demand around the North Sea, where the annual electricity consumption is about 1,300TWh.......The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (12-17kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost...... as in the Atlantic and the distance to shore relatively long compared to sites with good wave climate like Ireland, Portugal, Spain and the west coast of UK. The increasing activities within offshore wind in the North Sea and the attempt to build a super grid connecting the wind sites with the major consumers around...

  4. Quaternary evolution of the North Sea and the English Channel

    NARCIS (Netherlands)

    Gibbard, P.L.; Cohen, K.M.

    The island of Britain is surrounded by a ‘moat’ of water, of which the English Channel and the North Sea are two major components. This talk described some major events that occurred to shape these seaways and, in particular, the evidence preserved on the Channel seabed. Here a system of valleys

  5. The maximum significant wave height in the Southern North Sea

    NARCIS (Netherlands)

    Bouws, E.; Tolman, H.L.; Holthuijsen, L.H.; Eldeberky, Y.; Booij, N.; Ferier, P.

    1995-01-01

    The maximum possible wave conditions along the Dutch coast, which seem to be dominated by the limited water depth, have been estimated in the present study with numerical simulations. Discussions with meteorologists suggest that the maximum possible sustained wind speed in North Sea conditions is

  6. Temporal Variation of Iodine Isotopes in the North Sea

    DEFF Research Database (Denmark)

    He, Peng; Aldahan, Ala; Possnert, Göran

    2014-01-01

    Monitoring temporal variability of 129I in the North Sea, a relatively large reservoir of radioactive discharges from the nuclear fuel reprocessing facilities, is vital for the environmental situation in the region. New information on concentration levels and distribution of 129I and 127I and the...

  7. Spatial patterns of infauna, epifauna and demersal fish communities in the North Sea.

    NARCIS (Netherlands)

    Reiss, H.; Degraer, S.; Duineveld, G.C.A.; Craeymeersch, J.A.M.

    2010-01-01

    Understanding the structure and interrelationships of North Sea benthic invertebrate and fish communities and their underlying environmental drivers is an important prerequisite for conservation and spatial ecosystem management on scales relevant to ecological processes. Datasets of North Sea

  8. Cleaning up the sea bed in the North Sea. 1994

    International Nuclear Information System (INIS)

    1995-01-01

    The yearly raid was executed in an efficient way and without excess technical equipment interruptions. The vessel ''Lance'' owned by the Norwegian Sea Mapping Authorities which was used for the sonar mapping of the sea bed, was equipped with a Klein 531T side seeking sonar, a Simrad echo sounder of the type EM100 (multiray) and differential GPS navigation system. The executive committee has earlier expressed desire for a strengthening of the co-operation with the Norwegian Sea Mapping Authorities. The use of the vessel was in accordance with this wish. Stolt Comex Seaway A/S used the vessel M/S ''Seaway Commander'' and the underwater vessel ''Solo'' for the cleaning up project. The systems worked satisfactory during the entire operation. The cleaning operation was in 1994 carried out in 2 sections. The Petroleum Directorate agreed to letting the M/S ''Seaway Commander'' complete the project for Norsk Hydro at the Troll field in order to avoid delays in the Troll Oil project. In both periods there were good weather conditions. There was no extensive discontinuations due to the weather. During the two periods of 13,5 days 259 out of 370 positions were investigated visually through the systems. This is in average about 20 inspected positions a day. The reason for the high average is that the sailing distances are short between the positions and the findings corresponded to stated positions and sonar interpretations. Also this year there was installed a side seeking sonar in the underwater vessel which resulted in reduced investigation time at each aim. It was possible with this type of sonar to identify the goal quicker and to seek during transit between goals at moderate distances. Few articles with certainty contributed by the petroleum activities were retrieved

  9. What is the pollution status of North Sea sediments?

    International Nuclear Information System (INIS)

    Chapman, P.M.; Heip, C.; Cofino, W.

    1993-01-01

    A March 1990 international sea-going workshop in Bremerhaven, Germany provided the opportunity to conduct detailed sediment toxicity testing in concert with studies of fish histopathology, bioaccumulation, benthic community structure, and sediment chemical contamination in the North Sea. Two gradients of sediment chemical contamination were tested, one from an abandoned oil platform and the other from the mouth of the Elbe River northward to the Dogger Bank. Using a preponderance of evidence approach, it was determined that sediments nearest the Elbe are moderately polluted (pollution is defined as contamination, toxicity, and community alteration) and that sediments offshore and at the Dogger Bank are unpolluted. Sediments nearest the oil platform showed evidence for a low level of pollution, but there was no evidence of pollution 125 m from the platform. The results suggest the testable hypothesis that North Sea sediments away from point sources of pollution such as coastal areas and drilling platforms are presently not polluted. 46 refs., 2 figs., 6 tabs

  10. The ordered network structure of M {>=} 6 strong earthquakes and its prediction in the Jiangsu-South Yellow Sea region

    Energy Technology Data Exchange (ETDEWEB)

    Men, Ke-Pei [Nanjing Univ. of Information Science and Technology (China). College of Mathematics and Statistics; Cui, Lei [California Univ., Santa Barbara, CA (United States). Applied Probability and Statistics Dept.

    2013-05-15

    The the Jiangsu-South Yellow Sea region is one of the key seismic monitoring defence areas in the eastern part of China. Since 1846, M {>=} 6 strong earthquakes have showed an obvious commensurability and orderliness in this region. The main orderly values are 74 {proportional_to} 75 a, 57 {proportional_to} 58 a, 11 {proportional_to} 12 a, and 5 {proportional_to} 6 a, wherein 74 {proportional_to} 75 a and 57 {proportional_to} 58 a with an outstanding predictive role. According to the information prediction theory of Wen-Bo Weng, we conceived the M {>=} 6 strong earthquake ordered network structure in the South Yellow Sea and the whole region. Based on this, we analyzed and discussed the variation of seismicity in detail and also made a trend prediction of M {>=} 6 strong earthquakes in the future. The results showed that since 1998 it has entered into a new quiet episode which may continue until about 2042; and the first M {>=} 6 strong earthquake in the next active episode will probably occur in 2053 pre and post, with the location likely in the sea area of the South Yellow Sea; also, the second and the third ones or strong earthquake swarm in the future will probably occur in 2058 and 2070 pre and post. (orig.)

  11. Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

    DEFF Research Database (Denmark)

    Salt, Lesley A.; Thomas, Helmuth; Prowe, Friederike

    2013-01-01

    [1] High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO2 system...... of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive...... observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead...

  12. Storing CO2 under the North Sea Basin - A key solution for combating climate change

    International Nuclear Information System (INIS)

    Skogen, T; Morris, B; Agerup, M; Svenningsen, S Oe; Kropelien, K F; Solheim, M; Northmore, B; Dixon, T; O'Carroll, K; Greaves, A; Golder, J; Selmer-Olsen, S; Sjoeveit, A; Kaarstad, O; Riley, N; Wright, I; Mansfield, C

    2007-06-01

    This report represents the first deliverable of the North Sea Basin Task Force, which Norway and the UK established in November 2005 to work together on issues surrounding the transport and storage of CO 2 beneath the North Sea. The North Sea represents the best geological opportunity for storing our CO 2 emissions away from the atmosphere for both the UK and Norway

  13. Distribution and activity of petroleum hydrocarbon degrading bacteria in the North Sea and Baltic Sea

    International Nuclear Information System (INIS)

    Bruns, K.; Dahlmann, G.; Gunkel, W.

    1993-01-01

    Data were collected in 1988 and 1989 on the distribution and activity of petroleum hydrocarbon degrading bacteria in the North Sea and Baltic Sea. Crude oil degrading bacteria and the number of bacteria which in particular degrade naphthalene were quantified using a modified dilution method (MPN). Crude oil degrading bacteria were present in all of about 100 water samples, with as many as 10 3 ml -1 in some samples. Numbers of naphthalene degrading bacteria were at least tenfold lower. There is obviously a greater connection between this bacteria group and petroleum hydrocarbon (PHC) contamination than between the more nonspecific group of crude oil degrading bacteria and PHC contamination. Data from the North Sea show an extremely high abundance of hydrocarbon degrading bacteria, even in winter, while in the southern Baltic Sea low numbers of bacteria were found and slower crude oil degradation was observed. (orig.)

  14. Mechanisms of long-term mean sea level variability in the North Sea

    Science.gov (United States)

    Dangendorf, Sönke; Calafat, Francisco; Øie Nilsen, Jan Even; Richter, Kristin; Jensen, Jürgen

    2015-04-01

    We examine mean sea level (MSL) variations in the North Sea on timescales ranging from months to decades under the consideration of different forcing factors since the late 19th century. We use multiple linear regression models, which are validated for the second half of the 20th century against the output of a state-of-the-art tide+surge model (HAMSOM), to determine the barotropic response of the ocean to fluctuations in atmospheric forcing. We demonstrate that local atmospheric forcing mainly triggers MSL variability on timescales up to a few years, with the inverted barometric effect dominating the variability along the UK and Norwegian coastlines and wind (piling up the water along the coast) controlling the MSL variability in the south from Belgium up to Denmark. However, in addition to the large inter-annual sea level variability there is also a considerable fraction of decadal scale variability. We show that on decadal timescales MSL variability in the North Sea mainly reflects steric changes, which are mostly remotely forced. A spatial correlation analysis of altimetry observations and baroclinic ocean model outputs suggests evidence for a coherent signal extending from the Norwegian shelf down to the Canary Islands. This supports the theory of longshore wind forcing along the eastern boundary of the North Atlantic causing coastally trapped waves to propagate along the continental slope. With a combination of oceanographic and meteorological measurements we demonstrate that ~80% of the decadal sea level variability in the North Sea can be explained as response of the ocean to longshore wind forcing, including boundary wave propagation in the Northeast Atlantic. These findings have important implications for (i) detecting significant accelerations in North Sea MSL, (ii) the conceptual set up of regional ocean models in terms of resolution and boundary conditions, and (iii) the development of adequate and realistic regional climate change projections.

  15. Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

  16. Improving a prediction system for oil spills in the Yellow Sea: effect of tides on subtidal flow.

    Science.gov (United States)

    Kim, Chang-Sin; Cho, Yang-Ki; Choi, Byoung-Ju; Jung, Kyung Tae; You, Sung Hyup

    2013-03-15

    A multi-nested prediction system for the Yellow Sea using drifter trajectory simulations was developed to predict the movements of an oil spill after the MV Hebei Spirit accident. The speeds of the oil spill trajectories predicted by the model without tidal forcing were substantially faster than the observations; however, predictions taking into account the tides, including both tidal cycle and subtidal periods, were satisfactorily improved. Subtidal flow in the simulation without tides was stronger than in that with tides because of reduced frictional effects. Friction induced by tidal stress decelerated the southward subtidal flows driven by northwesterly winter winds along the Korean coast of the Yellow Sea. These results strongly suggest that in order to produce accurate predictions of oil spill trajectories, simulations must include tidal effects, such as variations within a tidal cycle and advections over longer time scales in tide-dominated areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Remote-Sensing Estimation of Phytoplankton Size Classes From GOCI Satellite Measurements in Bohai Sea and Yellow Sea

    Science.gov (United States)

    Sun, Deyong; Huan, Yu; Qiu, Zhongfeng; Hu, Chuanmin; Wang, Shengqiang; He, Yijun

    2017-10-01

    Phytoplankton size class (PSC), a measure of different phytoplankton functional and structural groups, is a key parameter to the understanding of many marine ecological and biogeochemical processes. In turbid waters where optical properties may be influenced by terrigenous discharge and nonphytoplankton water constituents, remote estimation of PSC is still a challenging task. Here based on measurements of phytoplankton diagnostic pigments, total chlorophyll a, and spectral reflectance in turbid waters of Bohai Sea and Yellow Sea during summer 2015, a customized model is developed and validated to estimate PSC in the two semienclosed seas. Five diagnostic pigments determined through high-performance liquid chromatography (HPLC) measurements are first used to produce weighting factors to model phytoplankton biomass (using total chlorophyll a as a surrogate) with relatively high accuracies. Then, a common method used to calculate contributions of microphytoplankton, nanophytoplankton, and picophytoplankton to the phytoplankton assemblage (i.e., Fm, Fn, and Fp) is customized using local HPLC and other data. Exponential functions are tuned to model the size-specific chlorophyll a concentrations (Cm, Cn, and Cp for microphytoplankton, nanophytoplankton, and picophytoplankton, respectively) with remote-sensing reflectance (Rrs) and total chlorophyll a as the model inputs. Such a PSC model shows two improvements over previous models: (1) a practical strategy (i.e., model Cp and Cn first, and then derive Cm as C-Cp-Cn) with an optimized spectral band (680 nm) for Rrs as the model input; (2) local parameterization, including a local chlorophyll a algorithm. The performance of the PSC model is validated using in situ data that were not used in the model development. Application of the PSC model to GOCI (Geostationary Ocean Color Imager) data leads to spatial and temporal distribution patterns of phytoplankton size classes (PSCs) that are consistent with results reported from

  18. Current meter components and other data from FIXED PLATFORMS from Yellow Sea (Hwang Hai) from 10 January 1986 to 30 June 1986 (NODC Accession 8800190)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the Yellow Sea (Hwang Hai) from 10 January 1986 to 30 June 1986. Data were collected by Florida...

  19. Sedimentary records of hydroxylated and methoxylated polybrominated diphenyl ethers in the southern Yellow Sea.

    Science.gov (United States)

    Fan, Ying; Lan, Jing; Zhao, Zongshan; Zhao, Meixun

    2014-07-15

    Although hydroxylated (OH-) and methoxylated (MeO-) polybrominated diphenyl ethers (PBDEs) have caused much concern in recent years, few reports had discussed on their input history. In this study, we measured the contents of nine MeO-BDEs, ten OH-BDEs, and total organic carbon (TOC) of two sediment cores from the southern Yellow Sea. 6-MeO-BDE-47, 2'-MeO-BDE-68, 6-OH-BDE-47, and 2'-OH-BDE-68 were the predominant congeners in HH12, while only 2'-OH-BDE-68 and 6-OH-BDE-47 were frequently detected in core HH11. The records showed that OH-/MeO-BDEs in both cores had increased rapidly since the 1950s. Their existence was detected at the bottom layers (∼1800 s) prior to the production of PBDEs (1960s), thus OH-/MeO-BDEs originate from natural origins rather than artificial PBDEs. Comparisons between TOC and OH-/MeO-BDEs indicated that TOC is a potential factor affecting the accumulation of OH-/MeO-BDEs in marine environments. Similar trends and significant correlations between OH-BDEs and MeO-BDEs suggest their common origins or interconversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Dynamics of the Sediment Plume Over the Yangtze Bank in the Yellow and East China Seas

    Science.gov (United States)

    Luo, Zhifa; Zhu, Jianrong; Wu, Hui; Li, Xiangyu

    2017-12-01

    A distinct sediment plume exists over the Yangtze Bank in the Yellow and East China Seas (YECS) in winter, but it disappears in summer. Based on satellite color images, there are two controversial viewpoints about the formation mechanism for the sediment plume. One viewpoint is that the sediment plume forms because of cross-shelf sediment advection of highly turbid water along the Jiangsu coast. The other viewpoint is that the formation is caused by local bottom sediment resuspension and diffused to the surface layer through vertical turbulent mixing. The dynamic mechanism of the sediment plume formation has been unclear until now. This issue was explored by using a numerical sediment model in the present paper. Observed wave, current, and sediment data from 29 December 2016 to 16 January 2017 were collected near the Jiangsu coast and used to validate the model. The results indicated that the model can reproduce the hydrodynamic and sediment processes. Numerical experiments showed that the bottom sediment could be suspended by the bottom shear stress and diffuse to the surface layer by vertical mixing in winter; however, the upward diffusion is restricted by the strong stratification in summer. The sediment plume is generated locally due to bottom sediment resuspension primarily via tide-induced bottom shear stress rather than by cross-shelf sediment advection over the Yangtze Bank.

  1. Clay mineral distribution and provenance in the Heuksan mud belt, Yellow Sea

    Science.gov (United States)

    Cho, Hyen Goo; Kim, Soon-Oh; Kwak, Kyeong Yoon; Choi, Hunsoo; Khim, Boo-Keun

    2015-12-01

    The Heuksan mud belt (HMB), located in the southeastern Yellow Sea, runs parallel to the southwest coast of Korea. In this study, the distribution and relative contribution of four major clay minerals are investigated using 101 surface sediment samples collected in the course of KIOST (2001, 2010, 2011) and KIGAM (2012) cruises, as well as 33 river sediment samples (four from the Huanghe River, three from the Changjiang River, and 26 from Korean rivers) in order to clarify the provenance of fine-grained sediments in the HMB. Based on this currently largest and most robust dataset available for interpretation, the clay mineral assemblages of the fine-grained sediments in the HMB are found to be on average composed of 64.7% illite, 17.9% chlorite, 11.4% kaolinite, and 5.9% smectite. Overall, the clay mineral assemblages are similar in both the northern and the southern parts of the HMB, although smectite seems to be relatively enriched in the southern part, whereas kaolinite is slightly more dominant in the northern part. This clearly indicates that the clays are mostly derived from Korean rivers and, in the southern part of the HMB, partly also from the Huanghe River in China. The new data thus confirm and strengthen the tentative interpretation of some earlier work based on a more limited dataset.

  2. Centennial-scale records of total organic carbon in sediment cores from the South Yellow Sea, China

    Science.gov (United States)

    Zhu, Qing; Lin, Jia; Hong, Yuehui; Yuan, Lirong; Liu, Jinzhong; Xu, Xiaoming; Wang, Jianghai

    2018-01-01

    Global carbon cycling is a significant factor that controls climate change. The centennial-scale variations in total organic carbon (TOC) contents and its sources in marginal sea sediments may reflect the influence of human activities on global climate change. In this study, two fine-grained sediment cores from the Yellow Sea Cold Water Mass of the South Yellow Sea were used to systematically determine TOC contents and stable carbon isotope ratios. These results were combined with previous data of black carbon and 210Pb dating from which we reconstructed the centennial-scale initial sequences of TOC, terrigenous TOC (TOCter) and marine autogenous TOC (TOCmar) after selecting suitable models to correct the measured TOC (TOCcor). These sequences showed that the TOCter decreased with time in the both cores while the TOCmar increased, particularly the rapid growth in core H43 since the late 1960s. According to the correlation between the Huanghe (Yellow) River discharge and the TOCcor, TOCter, or TOCmar, we found that the TOCter in the two cores mainly derived from the Huanghe River and was transported by it, and that higher Huanghe River discharge could strengthen the decomposition of TOCmar. The newly obtained initial TOC sequences provide important insights into the interaction between human activities and natural processes.

  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. Seabird biomass and food consumption in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Furness, R.W.

    1984-07-01

    Calculations presented by Bourne contain some order-of-magnitude errors, and give the misleading impression that estimates of fish consumption by seabirds in the North Sea may be as low as 0.25%, or as high as 48%, of fish production, depending on the method of calculation. It is likely that the true figure is closer to 20% once the errors in Bourne's calculations are corrected, but several areas of uncertainty require further study; particularly seabird diets and foraging ranges, fish distribution and movements. Studies from other parts of the world show that seabird numbers can dramatically alter in response to changes in food abundance. Some changes result from natural perturbations and others from effects of overexploitation of fish stocks by man. Effects of overfishing seem likely to be potentially, at least as serious, as effects of oil or chemical pollution in many regions, possibly including the North Sea. 48 references.

  5. UK wants more revenue from North Sea oil

    Energy Technology Data Exchange (ETDEWEB)

    1973-03-09

    The first report from the Committee of Public Accounts of the UK Parliament on North Sea gas and oil has revealed a situation under which the UK Exchequer apparently does not receive cash intake comparable to the Exchequers of other oil producing countries. So important are these findings that some of them are presented so that the industry at large, and particularly those engaged in North Sea exploration and production, will be aware of the UK situation. Recomendations are made that the government should take action substantially to improve the effective tax yield from operations on the continental shelf, and should consider among other methods the possibility of imposing a system of quantity taxation.

  6. Two centuries of extreme events over the Baltic Sea and North Sea regions

    Science.gov (United States)

    Stendel, Martin; den Besselaar Else, van; Abdel, Hannachi; Jaak, Jaagus; Elizabeth, Kent; Christiana, Lefebvre; Gudrun, Rosenhagen; Anna, Rutgersson; Frederik, Schenk; der Schrier Gerard, van; Tim, Woolings

    2017-04-01

    Two centuries of extreme events over the Baltic Sea and North Sea regions In the framework of the BACC 2 (for the Baltic Sea) and NOSCCA projects (for the North Sea region), studies of past and present variability and changes in atmospheric variables within the North Sea region over the instrumental period (roughly the past 200 years) have been investigated. Findings on trends in temperature and precipitation have already been presented. Here we focus on data homogeneity issues and examine how reliable reanalyses are in this context. Unlike most other regions in the world, there is a wealth of old observations available for the Baltic and North Sea regions, most of it in handwritten form in meteorological journals and other publications. These datasets need to be carefully digitised and homogenized. For this, a thorough quality control must be applied; otherwise the digitised datasets may prove useless or even counterproductive. We present evidence that this step cannot be conducted without human interference and thus cannot be fully automated. Furthermore, inhomogeneities due to e.g. instrumentation and station relocations need to be addressed. A wealth of reanalysis products is available, which can help detect such inhomogeneities in observed time series, but at the same time are prone to biases and/or spurious trends themselves e.g. introduced by changes in the availability and quality of the underlying assimilated data. It therefore in general remains unclear in how far we can simulate the pre-satellite era with respect to homogeneity with reanalyses based only on parts of the observing system. Extreme events and changes in extreme situations are more important and of greater (societal) significance than changes in mean climate. However, changes in extreme weather events are difficult to assess not only because they are, per definition, rare events, but also due to the homogeneity issues outlined above. Taking these into account, we present evidence for changes

  7. Ecology of the North Sea: Problems, successes, failures, future needs

    Science.gov (United States)

    Kinne, O.

    1995-03-01

    After defining ‘ecology’, outlining the basic categories of ecological research and listing examples of modern ecological investigations, this introductory paper focusses on basic considerations; it is, in essence, a programmatic contribution. Research details on the ecology of the North Sea are the subject of the following papers. The problems of ecological North Sea research are formidable. Hydrological and biological fluctuations and variabilities are pronounced. Exchange patterns with the Atlantic are complex, and the inputs of rivers and rain defy exact measurement and prediction. Season, weather, climate—and as yet insufficiently known and controlled human-caused impacts—further complicate the situation. All this results in an unusually high degree of uncertainty. New questions and problems arise before the old ones can be answered or solved. Nevertheless, ecological North Sea research has achieved many successes. The North Sea is the most intensively investigated sea area on our planet. Generations of zoologists, botanists and hydrographers — and more recently microbiologists, meteorologists, climatologists, chemists, pathologists and toxicologists — have produced an impressive body of knowledge. Slowly we are beginning to understand the forces that govern energy budgets and balances, material fluxes, and the factors that control and direct ecosystem dynamics. Essential driving forces of ecosystem dynamics result from microbial, especially bacterial, activities. Ecological modelling has paved the way for new theories and insights, and holds promise for progress towards a predictive ecology. Failures and shortcomings include insufficient long-term research, inadequately designed experiments, and misconceptions in environmental protection. Net changes in ecological processes of an heterogeneous and intensely varying environment such as the North Sea can only be comprehended adequately against the background of sustained measurements over decades

  8. Shallow gas in Cenozoic sediments of the Southern North Sea

    Science.gov (United States)

    Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

    2013-04-01

    Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

  9. Maps of mesoscale wind variability over the North Sea region

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Hahmann, Andrea N.; Badger, Jake

    Mesoscale wind fluctuations affect the operation of wind farms, particularly as the number of geographically concentrated wind farms in the North Sea increases (Akhmatov et al. 2007). The frequency and intensity of wind fluctuations could be considered as a new siting criterion, together with exi...... for a 1 year period. The model was run with a horizontal grid spacing of 2 km. The variability maps are created by integrating the average 24 hour spectra at every grid point over different time-scales....

  10. A synthesis of Cenozoic sedimentation in the North Sea

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Rasmussen, E.S.

    2012-01-01

    study provides a regional synthesis of sedimentation based on a comprehensive interpretation of a regionally covering reflection seismic data set. We relate observations of sediment characteristics and unconformities to the geological evolution. The timing, regional expression and stratigraphic...... characteristics of many unconformities indicate that they were generated by eustatic sea-level fall, often in conjunction with other processes. Early Cenozoic unconformities, however, relate to tectonism associated with the opening of the North Atlantic. From observation on a regional scale, we infer...

  11. North Sea market update: Changes in both concept and content

    International Nuclear Information System (INIS)

    Scruton, M.; Bru, J.G.

    1997-01-01

    The current paradox facing the North Sea offshore industry is that while it is experiencing a current market boom, within two years contractors may be scrambling around in a much reduced market. West Europe is running at a massive $15.1 billion. A veritable feast giving contractors, especially in Norway, a full workload and the headache of a severe skilled workforce shortage. Themes discussed cover Norwegian needs, Danish developments, UK utilisation, Dutch demand, and new breed. 4 figs

  12. North Sea trends typify industry's worldwide adjustment to change

    International Nuclear Information System (INIS)

    Nicandros, C.S.

    1993-01-01

    In response to rapid industry changes, oil companies are employing new practices and entering new relationships. In the U.K. North Sea's Britannia field, Conoco (U.K.) Ltd. and Chevron (U.K.) Ltd. share duties of field operator in the region's first such business arrangement. Here, the Neddrill 6 semisubmersible drills a Britannia appraisal well. This report tells how companies are using teamwork and other techniques to derive maximum value from their assets and technologies

  13. Independent companies in the North Sea - exploration and operations opportunities

    International Nuclear Information System (INIS)

    Greentree, C.

    1992-01-01

    The North Sea was the launching pad for many independent oil companies, particularly through exploration success in the UK and the Netherlands. Norway has an excellent history of oil exploration but, for the independents, the onerous tax regime, long lead times, and terms of trade are simply not conducive to the higher rate of return demanded by shareholders of independent E and P companies in exchange for shouldering the heavy burden of risk. The UK in particular has pursued imaginative licensing, tax and legislative policies which have allowed the independents an opportunity to participate and grow. The attraction of the UK is clearly reflected by the constant arrival of new entrants, even at this stage of maturity. This was demonstrated in the recent round of license awards. Such has been the success of the independents in the UK that, beginning with virtually nothing, they now hold a net 28% of the UK North Sea acreage, and a net 25% of its oil reserves. Equally, the independents play an important role in ensuring the comprehensive exploration of the offshore areas. Because of size and significance, a prime objective of the independents will remain the early evaluation, through drilling, and development of offshore interests to generate a financial return. This paper addresses the question of how independent companies can expand in the North Sea when the size and quality of new range acreage available through new license awards is reducing. (author)

  14. Fog composition at Baengnyeong Island in the eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    Directory of Open Access Journals (Sweden)

    A. J. Boris

    2016-01-01

    Full Text Available Samples of fog water were collected at Baengnyeong Island (BYI in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 µM, NO3− (1260 µM, SO4−2 (730 µM, and Na+ (551 µM, with substantial contributions from other species consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h showed that high relative humidity ( >  80 % was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, southeastern China, northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV concentrations were measured (mean of 2.36 µM in contrast to SO4−2 and in contrast to fog/cloud S(IV concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low-molecular-mass organic acids were major contributors to total organic carbon (TOC; 36–69 %, comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and

  15. Fog composition at Baengnyeong Island in the eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    Science.gov (United States)

    Boris, A. J.; Lee, T.; Park, T.; Choi, J.; Seo, S. J.; Collett, J. L., Jr.

    2016-01-01

    Samples of fog water were collected at Baengnyeong Island (BYI) in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 µM), NO3- (1260 µM), SO4-2 (730 µM), and Na+ (551 µM), with substantial contributions from other species consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h) showed that high relative humidity ( > 80 %) was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, southeastern China, northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV) concentrations were measured (mean of 2.36 µM) in contrast to SO4-2 and in contrast to fog/cloud S(IV) concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low-molecular-mass organic acids were major contributors to total organic carbon (TOC; 36-69 %), comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP) reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and fogs.

  16. Airborne gravity survey of Lincoln Sea and Wandel Sea, north Greenland

    DEFF Research Database (Denmark)

    Olesen, Arne Vestergaard; Forsberg, René; Keller, K.

    2000-01-01

    In June 1998 National Survey and Cadastre Denmark (KMS) carried out an airborne gravity survey over the Polar Sea to the north of Greenland. A Twin Otter from Greenlandair, equipped with autopilot and additional fuel tanks, was employed for the survey. A modified marine LaCoste & Romberg gravimet...

  17. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  18. First report of the planktonic copepod Oithona davisae in the northern Wadden Sea (North Sea): Evidence for recent invasion?

    Science.gov (United States)

    Cornils, Astrid; Wend-Heckmann, Britta

    2015-06-01

    In October 2010, specimens of Oithona were taken from the List Tidal Basin in the northern Wadden Sea (North Sea) for a biogeographic study on Oithona similis. These specimens could not be assigned to O. similis or any of the other Oithona species known from the North Sea genetically. These specimens were identified as Oithona davisae Ferrari and Orsi 1984, a Northwest Pacific species, known as an invasive species from the Black Sea and the northwestern Mediterranean Sea. Recent sampling provided evidence that O. davisae is still present in the northern Wadden Sea and may thus now be a permanent plankton species.

  19. 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)

  20. [Monitoring "green tide" in the Yellow Sea and the East China Sea using multi-temporal and multi-source remote sensing images].

    Science.gov (United States)

    Xing, Qian-Guo; Zheng, Xiang-Yang; Shi, Ping; Hao, Jia-Jia; Yu, Ding-Feng; Liang, Shou-Zhen; Liu, Dong-Yan; Zhang, Yuan-Zhi

    2011-06-01

    Landsat-TM (Theme Mapper) and EOS (Earth Observing System)-MODIS (MODerate resolution Imaging Spectrora-diometer) Terra/Aqua images were used to monitor the macro-algae (Ulva prolifera) bloom since 2007 at the Yellow Sea and the East China Sea. At the turbid waters of Northern Jiangsu Shoal, there is strong spectral mixing behavior, and satellite images with finer spatical resolution are more effective in detection of macro-algae patches. Macro-algae patches were detected by the Landsat images for the first time at the Sheyang estuary where is dominated by very turbid waters. The MODIS images showed that the macro-algae from the turbid waters near the Northern Jiangsu Shoal drifted southwardly in the early of May and affected the East China Sea waters; with the strengthening east-asian Summer Monsoon, macro-algae patches mainly drifted in a northward path which was mostly observed at the Yellow Sea. Macro-algae patches were also found to drift eastwardly towards the Korea Peninsular, which are supposed to be driven by the sea surface wind.

  1. Century-scale high-resolution black carbon records in sediment cores from the South Yellow Sea, China

    Science.gov (United States)

    Xu, Xiaoming; Hong, Yuehui; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Lirong; Wang, Jianghai

    2018-01-01

    Black carbon (BC) has received increasing attention in the last 20 years because it is not only an absorbent of toxic pollutants but also a greenhouse substance, preserving fire-history records, and more importantly, acting as an indicator of biogeochemical cycles and global changes. By adopting an improved chemothermal oxidation method (WXY), this study reconstructed the century-scale high-resolution records of BC deposition from two fine-grained sediment cores collected from the Yellow Sea Cold Water Mass in the South Yellow Sea. The BC records were divided into five stages, which exhibited specific sequences with three BC peaks at approximately 1891, 1921, and 2007 AD, representing times at which the first heavy storms appeared just after the termination of long-term droughts. The significant correlation between the times of the BC peaks in the cores and heavy storms in the area of the Huanghe (Yellow) River demonstrated that BC peaks could result from markedly strengthened sedimentation due to surface runoff, which augmented the atmospheric deposition. Stable carbon isotope analysis indicated that the evident increase in carbon isotope ratios of BC in Stage 5 might have resulted from the input of weathered rock-derived graphitic carbon cardinally induced by the annual anthropogenic modulation of water-borne sediment in the Huanghe River since 2005 AD. Numerical calculations demonstrated that the input fraction of graphitic carbon was 22.97% for Stage 5, whereas no graphitic carbon entered during Stages 1 and 3. The obtained data provide new and important understanding of the source-sink history of BC in the Yellow Sea.

  2. Temperature and salinity profile data collected by bottle on multiple cruises in the Baltic Sea, Baffin Bay, Davis Strait, the North Atlantic Ocean, and the North Sea from 02 January 1985 to 13 November 1989 (NODC Accession 0000056)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and nutrients data were collected using bottle casts from DANA and other platforms in Baffin Sea, Baltic Sea, Davis Strait, North Sea, and North...

  3. Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Nikolaos Kokkos

    2016-04-01

    Full Text Available A three-dimensional numerical model was applied to simulate the Black Sea Water (BSW outflux and spreading over the North Aegean Sea, and its impact on circulation and stratification–mixing dynamics. Model results were validated against satellite-derived sea surface temperature and in-situ temperature and salinity profiles. Further, the model results were post-processed in terms of the potential energy anomaly, ϕ, analyzing the factors contributing to its change. It occurs that BSW contributes significantly on the Thracian Sea water column stratification, but its signal reduces in the rest of the North Aegean Sea. The BSW buoyancy flux contributed to the change of ϕ in the Thracian Sea by 1.23 × 10−3 W m−3 in the winter and 7.9 × 10−4 W m−3 in the summer, significantly higher than the corresponding solar heat flux contribution (1.41 × 10−5 W m−3 and 7.4 × 10−5 W m−3, respectively. Quantification of the ϕ-advective term crossing the north-western BSW branch (to the north of Lemnos Island, depicted a strong non-linear relation to the relative vorticity of Samothraki Anticyclone. Similar analysis for the south-western branch illustrated a relationship between the ϕ-advective term sign and the relative vorticity in the Sporades system. The ϕ-mixing term increases its significance under strong winds (>15 m s−1, tending to destroy surface meso-scale eddies.

  4. Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea ice

    Science.gov (United States)

    Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.

    2017-08-01

    Arctic sea ice over the last few decades has experienced a significant decline in coverage both in summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea ice in the Nordic Seas (including the Barents Sea). More open water combined with the prevailing atmospheric pattern of airflow from the southeast, and persistent North Atlantic storms such as the recent extremely strong Storm Frank in December 2015, lead to increased energy transport to the high Arctic. Each of these storms brings sizeable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, Franz Joseph Land and Novaya Zemlya, and the associated heat release from open water into the atmosphere, contributed significantly to the increase in the downward longwave radiation throughout the entire Arctic. Added to other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W m-2, which can result in thinner (up to at least 15-20 cm) Arctic ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea ice.

  5. Inter-annual variability of North Sea plaice spawning habitat

    Science.gov (United States)

    Loots, C.; Vaz, S.; Koubbi, P.; Planque, B.; Coppin, F.; Verin, Y.

    2010-11-01

    Potential spawning habitat is defined as the area where environmental conditions are suitable for spawning to occur. Spawning adult data from the first quarter (January-March) of the International Bottom Trawl Survey have been used to study the inter-annual variability of the potential spawning habitat of North Sea plaice from 1980 to 2007. Generalised additive models (GAM) were used to create a model that related five environmental variables (depth, bottom temperature and salinity, seabed stress and sediment type) to presence-absence and abundance of spawning adults. Then, the habitat model was applied each year from 1970 to 2007 to predict inter-annual variability of the potential spawning habitat. Predicted responses obtained by GAM for each year were mapped using kriging. A hierarchical classification associated with a correspondence analysis was performed to cluster spawning suitable areas and to determine how they evolved across years. The potential spawning habitat was consistent with historical spawning ground locations described in the literature from eggs surveys. It was also found that the potential spawning habitat varied across years. Suitable areas were located in the southern part of the North Sea and along the eastern coast of England and Scotland in the eighties; they expanded further north from the nineties. Annual survey distributions did not show such northward expansion and remained located in the southern North Sea. This suggests that this species' actual spatial distribution remains stable against changing environmental conditions, and that the potential spawning habitat is not fully occupied. Changes in environmental conditions appear to remain within plaice environmental ranges, meaning that other factors may control the spatial distribution of plaice spawning habitat.

  6. Phytoplankton species composition of four ecological provinces in Yellow Sea, China

    Science.gov (United States)

    Li, Xiaoqian; Feng, Yuanyuan; Leng, Xiaoyun; Liu, Haijiao; Sun, Jun

    2017-12-01

    The ecological province based on phytoplankton species composition is important to understanding the interplay between environmental parameters and phytoplankton species composition. The aim of this study was to establish phytoplankton species composition ecological pattern thus elucidate the relationship between environmental factors and the phytoplankton species composition in the ecological provinces. Phytoplankton samples were collected from 31 stations in Yellow Sea (121.00°-125.00°E, 32.00°-39.22°N) in November 2014. The samples were enumerated and identified with the Utermöhl method under an optical inverted microscope-AE2000 with magnifications of 200 × or 400 ×. In the present study, a total of 141 taxa belonging to 60 genera of 4 phyla of phytoplankton were identified, among them 101 species of 45 genera were Bacillariophyta, 36 species of 11 genera were Dinophyta, 3 species of 3 genera were Chrysophyta and 1 species of 1 genera was Chlorophyta. The study area was divided into 4 ecological provinces according to an unsupervised cluster algorithm applied to the phytoplankton biomass. A T-S (Temperature-Salinity) scatter diagram depicted with data of water temperature and salinity defined by environmental provinces matched well with the ecological provinces. The results of Canonical Correspondence Analysis (CCA) indicated that the phytoplankton species composition was mainly correlated with temperature, salinity and silicate concentration in the studied area. A method of establishing ecological provinces is useful to further understanding the environmental effects on the marine phytoplankton species composition and the consequent marine biogeochemistry.

  7. Evidence for a Middle Pleistocene glaciation of MIS 8 age in the southern North Sea

    NARCIS (Netherlands)

    Beets, C.J.

    2005-01-01

    In the coresof borehole 89/2, situated at 541 00 010N and 51 00 040E about 70 km north of the Frisian Islands in the southern North Sea, two diamictonsle vels are found at 770 and 100m below sea floor (i.e. 7110 and 140 below present sea level), respectively. Both diamictonsap pear to be older than

  8. Air-sea exchange fluxes of synthetic polycyclic musks in the North Sea and the Arctic.

    Science.gov (United States)

    Xie, Zhiyong; Ebinghaus, Ralf; Temme, Christian; Heemken, Olaf; Ruck, Wolfgang

    2007-08-15

    Synthetic polycyclic musk fragrances Galaxolide (HHCB) and Tonalide (AHTN) were measured simultaneously in air and seawater in the Arctic and the North Sea and in the rural air of northern Germany. Median concentrations of gas-phase HHCB and AHTN were 4 and 18 pg m(-3) in the Arctic, 28 and 18 pg m(-3) in the North Sea, and 71 and 21 pg m(-3) in northern Germany, respectively. Various ratios of HHCB/AHTN implied that HHCB is quickly removed by atmospheric degradation, while AHTN is relatively persistent in the atmosphere. Dissolved concentrations ranged from 12 to 2030 pg L(-1) for HHCB and from below the method detection limit (3 pg L(-1)) to 965 pg L(-1) for AHTN with median values of 59 and 23 pg L(-1), respectively. The medians of volatilization fluxes for HHCB and AHTN were 27.2 and 14.2 ng m(-2) day(-1) and the depositional fluxes were 5.9 and 3.3 ng m(-2) day(-1), respectively, indicating water-to-air volatilization is a significant process to eliminate HHCB and AHTN from the North Sea. In the Arctic, deposition fluxes dominated the air-sea gas exchange of HHCB and AHTN, suggesting atmospheric input controls the levels of HHCB and AHTN in the polar region.

  9. Not normally manned compression platforms for the North Sea

    International Nuclear Information System (INIS)

    Kumaran, K.S.

    1994-01-01

    Gas turbine driven gas compressors have been widely used on manned offshore facilities. Similarly unmanned gas turbine driven compressor stations have been in operation onshore with major gas transmission companies in Europe, North America and elsewhere. This paper summarizes a recent joint industry study to investigate the technical and economic feasibility of Not Normally Manned (NNM) Offshore Compression Facilities in terms of reliability, availability and maintainability. Classification of not normally manned (or unmanned) offshore facilities in the UK North Sea is in accordance with HSE Operations Notice 8. ON8 specifies criteria for offshore visits, visit hours and number of personnel on board for the operation of NNM platforms. This paper describes a typical Southern North Sea gas platform being considered for NNM compressor application. The conclusions from the study was that NNM compression is technically feasible with the facilities being able to provide an availability in excess of 98%. Life cycle costs were of the order of 70% of manned facilities thus significantly improving field development economics

  10. Modelling the atmospheric transport of trace metals from Europe to the North Sea and the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, G; Weber, H; Grassl, H [GKSS-Forschungszentrum Geesthacht G.m.b.H., Geesthacht-Tesperhude (Germany, F.R.). Inst. fuer Physik

    1989-01-01

    Within the framework of a research contract with the German Federal Environmental Agency the long range transport of trace metals over Europe and the deposition of trace metals into the North Sea and the Baltic Sea are estimated using the EMEP- (European Monitoring and Evaluation Programme) trajectory model. The methodology for the model calculations is explained. Preliminary results for the total deposition of lead into the North Sea and the Baltic Sea show, that the calculated values are lower than previous estimates based on extrapolations from measurements at coastal sites and ship measurements in the southern Baltic Sea, respectively. (orig.).

  11. 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

    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...

  12. Phytoplankton of the North Sea and its dynamics: A review

    Science.gov (United States)

    Reid, P. C.; Lancelot, C.; Gieskes, W. W. C.; Hagmeier, E.; Weichart, G.

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m -2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of England, the Netherlands, Germany and Denmark. Data collected since 1932 during the Continuous Plankton Recorder Survey show consistent patterns of geographical, seasonal and annual variation in the distribution of phytoplankton and its major taxonomic components. There is a trend of increased colouration in Recorder silks in the southern North Sea until approximately 1975 since when Colour levels (assumed to be indicative of algal biomass) have declined. In the eutrophic Dutch Wadden Sea the algal crop continued to increase; in Dutch coastal North Sea waters a trend of biomass increase reversed since 1984, apparently due to a reduction in Rhine river outflow. Long-term observations made at Helgoland since the 60's also show trends of increasing nutrients and phytoplankton biomass only to 1984. Adverse effects such as deoxygenation, foam formation and toxin production have been linked to mass concentrations of algae known as blooms. There is no evidence from existing reports for an increase in their frequency, although some years stand out with larger numbers. Occurrence of blooms can partly be explained by hydrographic conditions. More than 30 taxa are recognised as occurring in bloom proportions in the North Sea, approximately one third of which can be toxic. The crop of Bacillariophyceae (diatoms) is not likely to increase with eutrophication due to silicate limitation. An extensive subsurface maximum of armoured dinoflagellates, its abundance gouverned by hydrographic conditions, is the most characteristic feature of the central and northern North Sea in the summer months. Abundance, sometimes dominance, of picoplankton and of species that are not readily detected by

  13. Sea Ice and Hydrographic Variability in the Northwest North Atlantic

    Science.gov (United States)

    Fenty, I. G.; Heimbach, P.; Wunsch, C. I.

    2010-12-01

    Sea ice anomalies in the Northwest North Atlantic's Labrador Sea are of climatic interest because of known and hypothesized feedbacks with hydrographic anomalies, deep convection/mode water formation, and Northern Hemisphere atmospheric patterns. As greenhouse gas concentrations increase, hydrographic anomalies formed in the Arctic Ocean associated with warming will propagate into the Labrador Sea via the Fram Strait/West Greenland Current and the Canadian Archipelago/Baffin Island Current. Therefore, understanding the dynamical response of sea ice in the basin to hydrographic anomalies is essential for the prediction and interpretation of future high-latitude climate change. Historically, efforts to quantify the link between the observed sea ice and hydrographic variability in the region has been limited due to in situ observation paucity and technical challenges associated with synthesizing ocean and sea ice observations with numerical models. To elaborate the relationship between sea ice and ocean variability, we create three one-year (1992-1993, 1996-1997, 2003-2004) three-dimensional time-varying reconstructions of the ocean and sea ice state in Labrador Sea and Baffin Bay. The reconstructions are syntheses of a regional coupled 32 km ocean-sea ice model with a suite of contemporary in situ and satellite hydrographic and ice data using the adjoint method. The model and data are made consistent, in a least-squares sense, by iteratively adjusting several model control variables (e.g., ocean initial and lateral boundary conditions and the atmospheric state) to minimize an uncertainty-weighted model-data misfit cost function. The reconstructions reveal that the ice pack attains a state of quasi-equilibrium in mid-March (the annual sea ice maximum) in which the total ice-covered area reaches a steady state -ice production and dynamical divergence along the coasts balances dynamical convergence and melt along the pack’s seaward edge. Sea ice advected to the

  14. Middle Holocene Organic Carbon and Biomarker Records from the South Yellow Sea: Relationship to the East Asian Monsoon

    Science.gov (United States)

    Zou, Liang; Hu, Bangqi; Li, Jun; Dou, Yanguang; Xie, Luhua; Dong, Liang

    2018-03-01

    The East Asian monsoon system influences the sedimentation and transport of organic matter in East Asian marginal seas that is derived from both terrestrial and marine sources. In this study, we determined organic carbon (OC) isotope values, concentrations of marine biomarkers, and levels of OC and total nitrogen (TN) in core YSC-1 from the central South Yellow Sea (SYS). Our objectives were to trace the sources of OC and variations in palaeoproductivity since the middle Holocene, and their relationships with the East Asian monsoon system. The relative contributions of terrestrial versus marine organic matter in core sediments were estimated using a two-end-member mixing model of OC isotopes. Results show that marine organic matter has been the main sediment constituent since the middle Holocene. The variation of terrestrial organic carbon concentration (OCter) is similar to the EASM history. However, the variation of marine organic carbon concentration (OCmar) is opposite to that of the EASM curve, suggesting OCmar is distinctly influenced by terrestrial material input. Inputs of terrestrial nutrients into the SYS occur in the form of fluvial and aeolian dust, while concentrations of nutrients in surface water are derived mainly from bottom water via the Yellow Sea circulation system, which is controlled by the East Asian winter monsoon (EAWM). Variations in palaeoproductivity represented by marine organic matter and biomarker records are, in general, consistent with the recent EAWM intensity studies, thus, compared with EASM, EAWM may play the main role to control the marine productivity variations in the SYS.

  15. Neogene dinocyst zonation for the eastern North Sea Basin, Denmark

    DEFF Research Database (Denmark)

    Dybkjær, Karen; Piasecki, Stefan

    2010-01-01

    A dinocyst zonation for the Neogene succession in the eastern part of the North Sea Basin (Denmark) is presented. The zonation is based on an extensive database comprising data from more than fifty onshore and offshore boreholes and about twenty five outcrops. Most of the nineteen dinocyst zones......, of the Lower Miocene, and of the Upper Miocene and Pliocene successions. The previous zonation of the onshore Danish Middle Miocene is reconsidered and partly redefined. The zonation is correlated with other biostratigraphic subdivisions of the Neogene succession in the Danish region in addition to litho...

  16. Fluid substitution studies for North Sea chalk logging data

    DEFF Research Database (Denmark)

    Gommesen, Lars; Mavko, G.; Mukerji, T.

    2002-01-01

    We have tested the application of respectively the Kuster-Toksöz and the Gassmann theory as a tool for predicting pore fluid from the elastic properties of brine-saturated North Sea reservoir chalk. We confirm that the Kuster-Toksöz model predicts a larger fluid effect thant the Gassmann model......, and show that the Kuster-Toksöz model fails to predict the presence of hydrocarbons. The Gassmann prediction for the near and potentially invaded zone corresponds more closely to logging data, than the Gassmann prediction for the far, virgin zone. We hereby conclude that the Gassmann theory predicts...

  17. Emerald oil field on production in North Sea

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Midland and Scottish Energy Ltd. (MSE) has placed Emerald oil field on stream in the U.K. North Sea with a floating production unit. Initial production, from two satellite wells, will be used to commission facilities. Three water injection wells have been unplugged and are ready for start-up. MSE will place a central cluster of wells-five producers and one water injector-on stream during the next few weeks. Production will build to an expected 25,000 b/d from 35 million bbl of reserves. Field development has undergone an unusually large number of setbacks and changes

  18. A three-dimensional mixed finite-difference Galerkin function model for the oceanic circulation in the Yellow Sea and the East China Sea in the presence of M 2 tide

    Science.gov (United States)

    Lee, Ho Jin; Jung, Kyung Tae; So, Jae Kwi; Chung, Jong Yul

    2002-01-01

    . Calculation with an inflow of 25.1 Sv through open boundaries on both sides of Taiwan shows that 1.15 Sv goes through Korea/Tsushima Strait, 0.36 Sv through the north of Tokara Strait (between Kyushu and Yakushima Island), 20.95 Sv through Tokara Strait and 2.77 Sv through open boundaries along the Ryukyu Islands. Calculations with fortnightly variation in M 2 open boundary forcings show that the oceanic circulation as well as tidal residuals vary significantly in the southern Yellow Sea; penetration of oceanic flows into the Yellow Sea occurs deeper at the neap tide than at the spring tide. The seasonal variation in the volume transport of the oceanic inflows/outflows without baroclinic effects has little effect on the exchange between the YS and the ECS.

  19. Phytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow Sea

    Science.gov (United States)

    Zhang, Chao; Gao, Huiwang; Yao, Xiaohong; Shi, Zongbo; Shi, Jinhui; Yu, Yang; Meng, Ling; Guo, Xinyu

    2018-02-01

    In this study, five on-board microcosm experiments were performed in the subtropical gyre, the Kuroshio Extension region of the northwest Pacific Ocean (NWPO), and the Yellow Sea (YS) in order to investigate phytoplankton growth following the addition of artificially modified mineral dust (AM dust) and various nutrients (nitrogen (N), phosphorus (P), iron (Fe), N + P, and N + P + Fe). The two experiments carried out with AM-dust addition in the subtropical gyre showed a maximum chlorophyll a (Chl a) concentration increase of 1.7- and 2.8-fold, while the cell abundance of large-sized phytoplankton ( > 5 µm) showed a 1.8- and 3.9-fold increase, respectively, relative to the controls. However, in the Kuroshio Extension region and the YS, the increases in maximum Chl a and cell abundance of large-sized phytoplankton following AM-dust addition were at most 1.3-fold and 1.7-fold larger than those in the controls, respectively. A net conversion efficiency index (NCEI) newly proposed in this study, size-fractionated Chl a, and the abundance of large-sized phytoplankton were analysed to determine which nutrients contribute to supporting phytoplankton growth. Our results demonstrate that a combination of nutrients, N-P or N + P + Fe, is responsible for phytoplankton growth in the subtropical gyre following AM-dust addition. Single nutrient addition, i.e., N in the Kuroshio Extension region and P or N in the YS, controls the phytoplankton growth following AM-dust addition. In the AM-dust-addition experiments, in which the increased N-P or P was identified to determine phytoplankton growth, the dissolved inorganic P from AM dust (8.6 nmol L-1) was much lower than the theoretically estimated minimum P demand (˜ 20 nmol L-1) for phytoplankton growth. These observations suggest that additional supply augments the bioavailable P stock in incubated seawater with AM-dust addition, most likely due to an enhanced solubility of P from AM dust or the remineralization of the dissolved

  20. Assessment of the environmental status for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Fryer, Rob; Andersen, Jesper H.

    to or at background”, green for “no harmful effect to the environment” and red for unacceptable. The HELCOM goals set out in the Baltic Sea action plan are similar, “concentrations of hazardous substances close to natural levels”, “all fish safe to eat”, and “healthy wildlife”. The assessment criteria used......The two Conventions for the Baltic Sea (Helsinki, HELCOM) and the North Sea (Oslo-Paris, OSPAR) both are in the process of assessing the state of the marine environment and producing Quality Status reports for their regions for publication in 2010. These assessments will be part of the basis...... for Marine Strategy work in the EU. An overview of the time trends and status for metals, PCBs and PAHs in biota and sediment for the convention areas will be presented, and the scientific basis for the assessments and how results from different contaminant groups and wider areas are aggregated...

  1. Formation of Barents Sea Branch Water in the north-eastern Barents Sea

    Directory of Open Access Journals (Sweden)

    Vidar S. Lien

    2013-09-01

    Full Text Available The Barents Sea throughflow accounts for approximately half of the Atlantic Water advection to the Arctic Ocean, while the other half flows through Fram Strait. Within the Barents Sea, the Atlantic Water undergoes considerable modifications before entering the Arctic Ocean through the St. Anna Trough. While the inflow area in the south-western Barents Sea is regularly monitored, oceanographic data from the outflow area to the north-east are very scarce. Here, we use conductivity, temperature and depth data from August/September 2008 to describe in detail the water masses present in the downstream area of the Barents Sea, their spatial distribution and transformations. Both Cold Deep Water, formed locally through winter convection and ice-freezing processes, and Atlantic Water, modified mainly through atmospheric cooling, contribute directly to the Barents Sea Branch Water. As a consequence, it consists of a dense core characterized by a temperature and salinity maximum associated with the Atlantic Water, in addition to the colder, less saline and less dense core commonly referred to as the Barents Sea Branch Water core. The denser core likely constitutes a substantial part of the total flow, and it is more saline and considerably denser than the Fram Strait branch as observed within the St. Anna Trough. Despite the recent warming of the Barents Sea, the Barents Sea Branch Water is denser than observed in the 1990s, and the bottom water observed in the St. Anna Trough matches the potential density at 2000 m depth in the Arctic Ocean.

  2. Islands of steel rise over North Sea gas. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Hind, J A

    1965-10-27

    Nowhere is the offshore oil and gas prospecting boom more enthusiastic, urgent, and crowded than in the North Sea. The type of rig required for this type of offshore drilling mainly depends upon how far offshore drilling is to take place. The fixed jack-up type is most suitable where depth of water is not excessive and for actual drilling operations were the drill is most easily held steady over the hole. This type of rig presents a stability problem under tow from location to location with a shallow depth of hull. Depth of water limits the operational mobility of the submerged-type rig and it is the most prone to scouring effects. Fully floating and ship-mounted rigs solve the depth of water problem and many others associated with ocean transportation. However, this is at the expense of more difficult drilling operations and complexity of equipment. Semi-submersibles are a popular compromise between fixed sit-on-bottom rigs and fully floating types. From a naval architectural point of view they have much to recommend them as all- round units. Typical North Sea drill rigs are described and a table is given for complete details.

  3. Analysis of North Sea Offshore Wind Power Variability

    Directory of Open Access Journals (Sweden)

    Aymeric Buatois

    2014-05-01

    Full Text Available This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identify the largest aggregated hourly power variations. Based on publicly available information, a simplified representation of the coastal power grid is built for the countries bordering the North Sea. Wind farms less than 60 km from shore are connected radially to the mainland, while the rest are connected to a hypothetical offshore HVDC (High-Voltage Direct Current power grid, designed such that wind curtailment does not exceed 1% of production. Loads and conventional power plants by technology and associated cost curves are computed for the various national power systems, based on 2030 projections. Using the MATLAB-based MATPOWER toolbox, the hourly optimal power flow for this regional hybrid AC/DC grid is computed for high, low and medium years from the meso-scale database. The largest net load variations are evaluated per market area and related to the extra load-following reserves that may be needed from conventional generators.

  4. The outlook for investment in the Norwegian North Sea

    International Nuclear Information System (INIS)

    Enger, T.

    1992-01-01

    An outline of the investment potential for oil and gas production on the Norwegian continental shelf is given. The continental shelf includes the Haltenbanken area and the Barents Sea as well as the North Sea. A description of existing projects and present knowledge of future prospects is given. The total production of oil and gas in 1990 was 107 million toe, the ratio of oil to gas production being 4:1. The relationship between oil and gas will change dramatically in the future however as the gas share in fields under development is much greater than in currently producing fields. The greatest potential for gas is expected to be in the Barents Sea which, being located at a considerable distance from existing gas markets presents a great challenge for commercial development. The conclusion drawn from the outline is that the present level of investment will be maintained or increase slightly over the next four to five years. For the period up to the turn of the century there is increasing uncertainty over the investment level which will become more and more dependent upon further expansion of gas exports but a best estimate is for continued investment stability beyond the year 2000. The production level can be expected to increase and reach a peak during the late 1990s. The resource base is sufficient to maintain a high production level for several decades after the year 2000. (UK)

  5. Coupling of the spatial-temporal distributions of nutrients and physical conditions in the southern Yellow Sea

    Science.gov (United States)

    Wei, Qin-Sheng; Yu, Zhi-Gang; Wang, Bao-Dong; Fu, Ming-Zhu; Xia, Chang-Shui; Liu, Lu; Ge, Ren-Feng; Wang, Hui-Wu; Zhan, Run

    2016-04-01

    This study investigated the coupling of the spatial-temporal variations in nutrient distributions and physical conditions in the southern Yellow Sea (SYS) using data compiled from annual-cycle surveys conducted in 2006-2007 as well as satellite-derived sea-surface temperature (SST) images. The influence of physical dynamics on the distribution and transport of nutrients varied spatially and seasonally in the SYS. The Changjiang Diluted Water (CDW) plume (in summertime), the Subei Coastal Water (SCW) (year-round), and the Lubei Coastal Current (LCC) (in wintertime) served as important sources of nutrients in the inshore area in a dynamic environment. The saline Taiwan Warm Current (TWC) might transport nutrients to the northeast region of the Changjiang Estuary in the summer, and this nutrient source began to increase from spring to summer and decrease when autumn arrived. Three types of nutrient fronts, i.e., estuarine, offshore, and coastal, were identified. A circular nutrient front caused by cross-shelf transport of SCW in the southeast shelf bank area in the winter and spring was observed. The southeastward flow of western coastal cold water in the SYS might be an important conduit for cross-shelf nutrient exchange between the SYS and the East China Sea (ECS). The tongue-shaped low-nutrient region in the western study area in the wintertime was driven by the interaction of the southward Yellow Sea Western Coastal Current (YSWCC) and the biological activity. The vertically variable SCM (subsurface Chl-a maximum) in the central SYS was controlled by coupled physical-chemical processes that involved stratification and associated nutricline. The average nutrient fluxes into the euphotic zone due to upwelling near the frontal zone of the Yellow Sea Cold Water Mass (YSCWM) in the summer are estimated here for the first time: 1.4 ± 0.9 × 103 μmol/m2/d, 0.1 ± 0.1 × 103 μmol/m2/d, and 2.0 ± 1.3 × 103 μmol/m2/d for DIN, PO4-P, and SiO3-Si, respectively. The

  6. In situ flume measurements of resuspension in the North Sea

    Science.gov (United States)

    Thompson, C. E. L.; Couceiro, F.; Fones, G. R.; Helsby, R.; Amos, C. L.; Black, K.; Parker, E. R.; Greenwood, N.; Statham, P. J.; Kelly-Gerreyn, B. A.

    2011-07-01

    The in situ annular flume, Voyager II, was deployed at three sites in the North Sea in order to investigate resuspension events, to determine the physical characteristics of the seabed, to determine the threshold of resuspension of the bed and to quantify erosion rates and erosion depths. These are the first controlled, in situ flume experiments to study resuspension in the North Sea, and were combined with long-term measurements of waves and currents. Resuspension experiments were undertaken at two muddy, and one sandy site: north of the Dogger Bank (DG: water depths ˜80 m, very fine, poorly sorted, very fine-skewed sediment experiencing seasonal thermal stratification of the water column along with oxygen depletion); the Oyster Grounds (OG: ˜40 m, similar bed properties, year round water column thermal stratification, Atlantic forcing); and in the Sean Gas Field (SGF: ˜20 m, moderately sorted, very coarse-skewed sand, and well mixed water column). The erosion thresholds of the bed were found to be 0.66-1.04 Pa (DG) and 0.91-1.27 Pa (OG), with corresponding erosion depths of 0.1-0.15 mm and 0.02-0.06 mm throughout the experiments. Evaluation of a year of current velocities from 2007 indicated that at OG, resuspension of the consolidated bed was limited to on average ˜8% of the time as a result of tidal forcing alone for short (properties of the bed. Therefore, while complex variations in biogeophysical factors affected the critical threshold of erosion, once exceeded, erosion rates were related to the nature of the sediment.

  7. Isolation of perchlorate-reducing Azospira suillum strain JB524 from tidal flats of the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Nirmala Bardiya

    2016-11-01

    Full Text Available Objective: To isolate and identify perchlorate-reducing bacterium from an enriched consortium from tidal flats of the Yellow Sea. Methods: A perchlorate-enriched consortium from tidal flats of the Yellow Sea was used to isolate Azospira suillum (A. suillum strain JB524. The strain was identified based on partial 16S rDNA sequencing. Perchlorate reduction by the strain was tested with acetate as the e - donor in the presence of NaCl, nitrate and at different growth temperatures using standard anaerobic techniques. The complete enzymatic destruction of perchlorate was confirmed as evolution of O2 by chlorite dismutase in the absence of acetate. Results: Strain JB524 shared 100% 16S rDNA sequence similarity with the type strain A. suillum PST isolated from a swine waste treatment lagoon. Perchlorate reduction coincided with concomitant increase in cell density. Although, acclimatization of the strain PST at suboptimal temperature for perchlorate reduction is not reported, the newly isolated strain could rapidly reduce perchlorate at 22 °C after brief acclimatization. Conclusions: Reduction of perchlorate by A. suillum strain JB524 was negatively affected in the presence of NaCl, suboptimal temperature, presence of nitrate, and limiting amount of acetate as the e-donor.

  8. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T.

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  9. 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.

  10. Morphological response to a North Sea bed depression induced by gas mining

    NARCIS (Netherlands)

    Fluit, C.C.J.M.; Hulscher, Suzanne J.M.H.

    2002-01-01

    Gas mining leads to saucer-like surface depressions. In the North Sea, gas is currently mined at several offshore locations. The associated bed depression has a similar spatial extent as offshore tidal sandbanks, which are large-scale bed patterns covering a significant part of the North Sea bottom.

  11. Diversity and community structure of epibenthic invertebrates and fish in the North Sea

    DEFF Research Database (Denmark)

    Callaway, R.; Alsväg, J.; de Boois, I.

    2002-01-01

    The structure of North Sea benthic invertebrate and fish communities is an important indicator of anthropogenic and environmental impacts. Although North Sea fish stocks are monitored regularly, benthic fauna are not. Here, we report the results of a survey carried out in 2000, in which five...

  12. Modelling thermal stratification in the North Sea: Application of a 2-D potential energy model

    DEFF Research Database (Denmark)

    Nielsen, Morten Holtegaard; St. John, Michael

    2001-01-01

    is forced with wind, dew point temperature from Ekofisk oilfield in the central North Sea, and tidal current and atmospheric radiation. The model is used to simulate the seasonal cycle of stratification in the central North Sea in the years 1988, 1989 and 1990 and is compared to density profiles...

  13. Plutonium and americium in arctic waters, the North Sea and Scottish and Irish coastal zones

    DEFF Research Database (Denmark)

    Hallstadius, L.; Aarkrog, Asker; Dahlgaard, Henning

    1986-01-01

    Plutonium and americium have been measured in surface waters of the Greenland and Barents Seas and in the northern North Sea from 1980 through 1984. Measurements in water and biota, Fucus, Mytilus and Patella, were carried out in North-English and Scottish waters in 1982 and Fucus samples were co...

  14. Prey selection by North Sea herring (Clupea harengus) with special reference to fish eggs

    NARCIS (Netherlands)

    Segers, F.H.I.D.; Dickey-Collas, M.; Rijnsdorp, A.D.

    2007-01-01

    The herring stock in the North Sea in recent years has recovered to a relatively high biomass, and here we investigate prey selection of individual North Sea herring when population numbers are high. The diet composition, and specifically pelagic fish eggs, was investigated in February 2004. Samples

  15. North Sea mackerel egg survey: dutch participation may and June 2011

    NARCIS (Netherlands)

    Damme, van C.J.G.

    2012-01-01

    Every three years an international North Sea survey is carried out by two European institutes, Institute for Marine Research (IMR) from Norway and Institute for Marine Resources and Ecosystem Studies (IMARES) from the Netherlands, to monitor the spatial and seasonal distribution of North Sea

  16. Micro contaminants in surface sediments and macrobenthic invertebrates of the North Sea

    NARCIS (Netherlands)

    Everaarts, J.M.; Fischer, C.V.

    1989-01-01

    Trace metal concentrations (copper, zinc, cadmium and lead) were measured in the silt fraction (grainsize < 63 µm) of surface sediment of the North Sea. The concentrations varied in different areas of the Dutch continental shelf of the North Sea. The trace metal concentrations were highly related

  17. The Pleistocene reindeer of the North Sea - initial palaeontological data and archaeological remarks

    NARCIS (Netherlands)

    Glimmerveen, J; Mol, D; van der Plicht, H

    The interdisciplinary North Sea Project aims at investigating the biotic history of the Pleistocene in the Southern Bight of the North Sea. Humans were part of these biotopes too as Palaeolithic flint artefacts prove. Based on a large fossil record and radiocarbon dating, it becomes clear that

  18. Phase equilibrium of North Sea oils with polar chemicals: Experiments and CPA modeling

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; Kontogeorgis, Georgios M.; von Solms, Nicolas

    2016-01-01

    This work consists of a combined experimental and modeling study for oil - MEG - water systems, of relevance to petroleum applications. We present new experimental liquid-liquid equilibrium data for the mutual solubility of two North Sea oils + MEG and North Sea oils + MEG + water systems...

  19. Trace elements in a North Sea drill core

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar; Gwozdz, R.; Svendsen, N.

    1986-01-01

    , V, Sr, Dy, Mg, Ti, Ba and Eu. The major elements Ca and Al could be related to petrophysical parameters, particularly Al which shows a correlation with the silicification/argillaceous content. Na (and Cl) has a low content in the hydrocarbon-bearing section of the drill core suggesting that the pore......Chalk samples, systematically taken along a drill core from one of the hydrocarbon producing fields of the North Sea (Tyra field), were analysed by a neutron activation technique involving measurement of radioisotopes with relatively short half-lives. Elements determined include Na, Al, Cl, Ca, Mn...... space is filled mainly by hydrocarbons. A significant decrease of Mn with depth probably suggests diagenesis of chalk prior to, or with, hydrocarbon emplacement. Investigations of drilling fluids and cuttings reveal a strong contamination of the latter, mainly by Ba. Chalk data from comparable onshore...

  20. Subsurface phytoplankton blooms fuel pelagic production in the North Sea

    DEFF Research Database (Denmark)

    Richardson, Kathrine; Visser, Andre; Pedersen, Flemming

    2000-01-01

    The seasonal phytoplankton biomass distribution pattern in stratified temperate marine waters is traditionally depicted as consisting of spring and autumn blooms. The energy source supporting pelagic summer production is believed to be the spring bloom. However, the spring bloom disappears...... relatively quickly from the water column and a large proportion of the material sedimenting to the bottom following the spring bloom is often comprised of intact phytoplankton cells. Thus, it is easy to argue that the spring bloom is fueling the energy demands of the benthos, but more difficult to argue...... convincingly that energy fixed during the spring bloom is fueling the pelagic production occurring during summer months. We argue here that periodic phytoplankton blooms are occurring during the summer in the North Sea at depths of >25 m and that the accumulated new production [sensu (Dugdale and Goering...

  1. Effects of changes in UK North Sea oil taxation

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, A G; Crichton, D

    1979-10-01

    Changes in North Sea oil tax structure were introduced by the United Kingdom government in mid-1979. The new system is aimed at increasing revenues to the state without damage to exploitation and production. The effects that the new tax regime and each of its components will have on different types of fields being exploited under various circumstances are examined. The analysis also considers sensitivity to capital-cost inflation, effects on multi-field operation, and the results of two other possible tax schemes. It is found that the new tax scheme will considerably alter the structure of the tax burden and will increase the overall tax take. Marginal tax rates will also increase, not least for some fields with low expected returns. The new scheme will, however, continue to favor capital-intensive exploitation techniques. 2 references, 17 tables.

  2. Well data summary sheets. Vol. 33: North sea wells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This 33rd volume of the `Well Data Summary sheets` includes data from seven recently released offshore wells from the North Sea. The wells Baron-2, S.E. Adda-1 and Skjold Flank-1 were presented in our `Well Data Summary Sheets, special volume`, published May 1, 1997. In volume 33, the wells Baron-2 and Skjold Flank-1 are updated with respect to information on sidewall cores. Information regarding all released well data, included in our well data summary sheets, are available on GEUS homepage: http://www.geus.dk/ or the departments homepage: http://www.geus.dk/departments/geol-info-data-centre/geoldata.htm/. A complete index of releases wells in volumes 17-33 is included. (au)

  3. Coastal Erosion and Flooding Hazards on the North Sea Coast at Thyboron, Denmark

    DEFF Research Database (Denmark)

    Sørensen, Per; Sørensen, Carlo Sass; Nielsen, Peter

    Since a breach of the coastal barrier in 1862, the Thyboron Channel connecting the North Sea and the Lim Fiord has been artificially maintained by construction of breakwaters and groins on the North Sea coast and inside the channel, respectively. Sand nourishment schemes have since the 1980s coun...... counteracted the natural erosion in the upper profile on the North Sea coast where the alongshore sediment transport converges towards the channel and deposits up to 1 million m3/y on the flood tidal delta inside the fiord, Figure 1.......Since a breach of the coastal barrier in 1862, the Thyboron Channel connecting the North Sea and the Lim Fiord has been artificially maintained by construction of breakwaters and groins on the North Sea coast and inside the channel, respectively. Sand nourishment schemes have since the 1980s...

  4. Potential Impacts of Offshore Wind Farms on North Sea Stratification

    Science.gov (United States)

    Carpenter, Jeffrey R.; Merckelbach, Lucas; Callies, Ulrich; Clark, Suzanna; Gaslikova, Lidia; Baschek, Burkard

    2016-01-01

    Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions—both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios. PMID:27513754

  5. Coccolithophore assemblage response to Black Sea Water inflow into the North Aegean Sea (NE Mediterranean)

    Science.gov (United States)

    Karatsolis, B.-Th.; Triantaphyllou, M. V.; Dimiza, M. D.; Malinverno, E.; Lagaria, A.; Mara, P.; Archontikis, O.; Psarra, S.

    2017-10-01

    This study aims to presents the species composition of living coccolithophore communities in the NE Aegean Sea, investigating their spatial and temporal variations along a north-south transect in the area receiving the inflowing surface Black Sea Water (BSW) over the deeper Levantine Water (LW) layer. Coccolithophores in the area were relatively diverse and a total of 95 species over 3 sampling periods studied were recognized using Scanning Electron Microscope (SEM) techniques. R-mode hierarchical cluster analysis distinguished two coccolithophore Groups (I, IIa, IIb, IIc) with different ecological preferences. Emiliania huxleyi was the most abundant species of Group I, whereas Syracosphaera spp., Rhabdosphaera spp. and holococcolithophores were prevailing in the highly diversified Group II assemblages. Biometric analysis conducted on E. huxleyi coccoliths from Aegean water column and Black Sea sediment trap samples, indicated that during autumn, NE Aegean specimens in samples under BSW influence were featured by unimodal distribution concerning the coccolith relative tube width, with values similar to those provided by the Black Sea specimens. In early spring, coccoliths in the stations with increased BSW influx displayed a bimodal pattern of relative tube width with smaller values found mostly in the surface layers, while the distribution became again unimodal and dominated by larger values within the deeper LW layers. In the summer period, the typical LW holococcolithophore species (Group II) presented low cell numbers in the surface layer (huxleyi was almost absent in the NE Aegean during the summer sampling period.

  6. Clean-up of the sea bed in the North Sea 1996

    International Nuclear Information System (INIS)

    1997-01-01

    The petroleum activities in the North Sea have inadvertently caused some conflict with fishermen getting their trawls etc. into trash from littering of the sea bed. In the present report, the Norwegian Petroleum Directorate describes a clean-up operation undertaken in 1996 and paid by the State. A clean-up area of 1000 km 2 off Karmoey was selected. This area was mapped by side scan sonar along survey lines 300 m equidistant and a sonar range of 200 m. The sonar data were continuously interpreted by a geophysicist. Selected targets were then identified by ROV and eventually removed. Of the 59 targets examined, 11 were removed and dumped onshore. The largest part elevated was a chain cable of 9 tons. There is also a brief discussion of the compensation agreement with Norwegian fishermen. 4 figs

  7. Sea Spray Aerosol Production over the North Atlantic

    Science.gov (United States)

    Bates, T. S.; Quinn, P.

    2017-12-01

    Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

  8. The North Sea oil and gas industry and the environment

    International Nuclear Information System (INIS)

    Kingston, P.F.

    1992-01-01

    The North Sea environment is described. Inputs into this environment from oil and gas installations are relatively modest compared with the pollution from effluent discharged or directly dumped into the sea by its highly populated and industrialized enclosing nations. Hydrocarbon discharges provide the greatest input from the oil and gas industry and make a substantial contribution to the total hydrocarbon input. The sources from offshore installations are analysed. Accidental spills, flaring, atmospheric emissions and other inputs are discussed. Biological and chemical monitoring over many year has shown that the most common environmental effect is a marked fall in the number of species of marine fauna and an increase in the number of individuals. These effects appear within 1000 metres of the installation. The spread of contaminants may be more widespread than the biological response indicates, though. The cost of environmental protection is briefly considered. A need to determined the wider impact of low levels of contamination detected at greater distances from platform activities and the development of effective environmental management plans are identified as two objectives for the future. (UK)

  9. Impact of North Atlantic Current changes on the Nordic Seas and the Arctic Ocean

    OpenAIRE

    Kauker, Frank; Gerdes, Rüdiger; Karcher, Michael; Köberle, Cornelia

    2005-01-01

    The impact of North Atlantic Current (NAC) volume, heat, and salt transport variability onto the NordicSeas and the Arctic Ocean is investigated using numerical hindcast and sensitivity experiments. Theocean-sea ice model reproduces observed propagation pathways and speeds of SST anomalies.Part of the signal reaching the entrance to the Nordic Seas between Iceland and Scotland originatesin the lower latitude North Atlantic. Response experiments with different prescribed conditionsat 50N show ...

  10. Transport and hydraulically-induced recycling of phosphorous in the North Sea-Baltic Sea transition zone

    DEFF Research Database (Denmark)

    Kepp, Rikke; Struve, Anke; Christiansen, Christian

    2006-01-01

    to barotropic and tidal currents the gross transport is 5 times larger. The net transport is directed towards the North Sea mainly in the top 32 m of the water column but towards the Baltic Sea it occurs in the lower 5 m of the water column. The resulting transport of phosphorus is strongly affected by vertical...

  11. Land-sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

    NARCIS (Netherlands)

    Donders, Timme; Van Helmond, Niels A.G.M.; Verreussel, Roel; Munsterman, Dirk; Veen, Johan Ten; Speijer, Robert P.; Weijers, Johan W.H.; Sangiorgi, Francesca; Peterse, Francien; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.; Lourens, Lucas; Kuhlmann, Gesa; Brinkhuis, Henk

    2018-01-01

    We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (ĝ1/4 2.6-1.8ĝ€Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of

  12. An Ichthyophonus hoferi epizootic in herring in the North Sea, the Skagerrak, the Kattegat and the Baltic Sea

    DEFF Research Database (Denmark)

    Mellergaard, Stig; Spanggaard, Bettina

    1997-01-01

    An epizootic caused by the internal parasite Ichthyophonus hoferi in herring Clupea harengus was recorded from 1991 to 1993 in the waters around Denmark. A surveillance programme from research vessels and commercial fishing boats was conducted in the North Sea, Skagerrak, Kattegat and Baltic Sea...

  13. The North sea, one of the group's anchorage points

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The North Sea is one of the pillars of the Elf Aquitaine group's Exploration-Production strategy. The most recent start-up in the North Sea, last february, concerned the Froy field where Elf Petroleum Norge (AS) is an operator with a 24.573 % interest alongside Statoil, Total Norge AS (15.2346 %) and Norsk Hydro. The first gas sales occurred on June 15, as scheduled. The oil production marketed by Elf (net of royalties) remained stable at 13.9 Gm 3 . At january 1,1995, Elf Aquitaine's mining area covered a gross surface area of 435,894 km 2 . In countries where the group is already established, the policy is : - to withdraw from exploration licenses considered as being the least promising in terms of discovery or profitability; - to concentrate on sectors where the existing production means allow for an optimisation of later developments ; - to penetrate more extensive exploration areas with good targets. In the British zone, the additional reserves revealed in the Elgin and Franklin condensate fields have doubled the initial forecast, placing the former among the major fields. All the discoveries made in the British zone have allowed the group to renew productions until now. Elf's production in Piper, Saltire, Chanter is 100,000 b/d which is added to the production of the Claymore and Scapa fields (100,000 b/d). The Flotta terminal processes the crude coming from these fields to which is added the production from the neighbouring fields of Tartan (Texaco) and Ivanhoe-Rob Roy (Amerada Hess), i.e. a total of more than 300,000 b/d. Other than Elgin or the Viking Graben, the future of the Elf group in Great Britain will most certainly come from the West Shetlands and the Irish Sea. In the Norwegian zone, the group has interest in the Frigg, Heimldal, Ekofisk, Valhall, Lille-Frigg, Froy, Oseberg, Hod, Sleipner East an Sleipner West Brage, Troll, Snorre, Statfjord East and Tordis production fields. (authors). 3 tabs., 1 photo

  14. Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

    Science.gov (United States)

    Flint, Paul L.

    2013-01-01

    Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

  15. An Ichthyophonus hoferi epizootic in herring in the North Sea, the Skagerrak, the Kattegat and the Baltic Sea

    OpenAIRE

    Mellergaard, Stig; Spanggaard, Bettina

    1997-01-01

    An epizootic caused by the internal parasite Ichthyophonus hoferi in herring Clupea harengus was recorded from 1991 to 1993 in the waters around Denmark. A surveillance programme from research vessels and commercial fishing boats was conducted in the North Sea, Skagerrak, Kattegat and Baltic Sea. A total of 15769 hearts of adult herring were examined macroscopically for evidence of infection. The prevalence of the infection in this period decreased from 10.6 to 2.0% in the North Sea, from 8.0...

  16. Climate change facilitated range expansion of the non-native angular crab Goneplax rhomboides into the North Sea

    NARCIS (Netherlands)

    Neumann, H.; Boois, de I.J.; Kroncke, I.; Reiss, H.

    2013-01-01

    The angular crab Goneplax rhomboides is native to the north-eastern Atlantic and Mediterranean Sea. It has rarely been reported from the North Sea, with no evidence of sustainable populations. Compiled survey data, however, revealed an increasing abundance of this species in the North Sea since

  17. What Causes the North Sea Level to Rise Faster over the Last Decade ?

    Science.gov (United States)

    Karpytchev, Mikhail; Letetrel, Camille

    2013-04-01

    We combined tide gauge records (PSMSL) and satellite altimetry data (TOPEX/POSEIDON-JASON 1-2) to reconstruct the mean level of the North Sea and the Norwegian Sea Shelf (NS-NSS) over 1950-2012. The reconstructed NS-NSS mean sea level fluctuations reveal a pronounced interannual variability and a strong sea level acceleration since the mid-1990's. In order to understand the causes of this acceleration, the NS-NSS mean sea level was cross-correlated with the North Atlantic Oscillation and Arctic Oscillation indices. While the interannual variability of the mean sea level correlates well with the NAO/AO indices, the observed acceleration in the NS-NSS mean level is not linked linearly to the NAO/AO fluctuations. On the other hand, the Empirical Orthogonal Functions (EOF) analysis of steric sea level variations in the eastern North Atlantic gives a dominant EOF pattern (55% of variance explained) that varies on a decadal scale very closely to the NS-NSS mean level flcutuations. Also, the amplification in the temporal amplitude of the dominant steric sea level EOF corresponds to the acceleration observed in the NS-NSS mean sea level signal. This suggests that decadal variations in the mean level of the North Sea - the Norwegian Sea Shelf reflect changes in the Subpolar Front currents (Rossby, 1996).

  18. Persistent use of a shorebird staging site in the Yellow Sea despite severe declines in food resources implies a lack of alternatives

    NARCIS (Netherlands)

    Zhang, Shou-Dong; Ma, Zhijun; Choi, Chi-Yeung; Peng, He-Bo; Bai, Qing-Quan; Liu, Wen-Liang; Tan, Kun; Melville, David S.; He, Peng; Chan, Ying-Chi; Piersma, Theunis; van Gils, Jan A.

    2018-01-01

    Many shorebird populations are in decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands in the Yellow Sea, which provide critical stop-over sites during migration, is believed to be the cause of the alarming trends. The Yalu Jiang coastal wetland, a protected area in

  19. Multi-resource data-based research on remote sensing monitoring over the green tide in the Yellow Sea

    Science.gov (United States)

    Gao, Zhiqiang; Xu, Fuxiang; Song, Debin; Zheng, Xiangyu; Chen, Maosi

    2017-09-01

    This paper conducted dynamic monitoring over the green tide (large green alga—Ulva prolifera) occurred in the Yellow Sea in 2014 to 2016 by the use of multi-source remote sensing data, including GF-1 WFV, HJ-1A/1B CCD, CBERS-04 WFI, Landsat-7 ETM+ and Landsta-8 OLI, and by the combination of VB-FAH (index of Virtual-Baseline Floating macroAlgae Height) with manual assisted interpretation based on remote sensing and geographic information system technologies. The result shows that unmanned aerial vehicle (UAV) and shipborne platform could accurately monitor the distribution of Ulva prolifera in small spaces, and therefore provide validation data for the result of remote sensing monitoring over Ulva prolifera. The result of this research can provide effective information support for the prevention and control of Ulva prolifera.

  20. The roles of different mechanisms related to the tide-induced fronts in the Yellow Sea in summer

    Science.gov (United States)

    Ren, Shihe; Xie, Jiping; Zhu, Jiang

    2014-09-01

    In summer, the Yellow Sea Cold Water Mass (YSCWM) is a stable water mass of low temperature lying at the bottom of the central Yellow Sea (YS). It is fringed by some typical tidal fronts, which separate deep, stratified water on the offshore side from the well-mixed, shallow water on the inshore side. Three striking fronts—Subei Bank Front (SBF), Shandong Peninsula Front (SPF), and Mokpo Front (MKF; a front off the southwestern tip of the Korean Peninsula)—have been identified by various studies from both satellite observations and model results. Tide plays an important role in the formation and maintenance of these fronts. However, it is still a matter of debate as to the roles these two kinds of mechanisms of upwelling and tidal mixing play, and how importance they are in the maintenance processes of the above three fronts. Basing a nested high-resolution model HYCOM (the Hybrid Coordinate Ocean Model), this study focuses on the different mechanisms of tidal effects on the thermal fronts in the YS in summertime. Through comparative experiments with and without tidal forcing, the results indicate that the MKF is mainly driven by tide-induced upwelling. For the SPF, tidal mixing is the dominant factor, when lower cold water is stirred upwards along the sloping topography of the western YS. Meanwhile, the combined effect of upwelling and tidal mixing is the main cause of the formation of the SBF. Diagnostic analysis of thermal balance shows that horizontal nonlinear advection induced by strong tidal currents also contributes to the thermal balance of frontal areas.

  1. Exploring spatiotemporal changes of the Yangtze River (Changjiang) nitrogen and phosphorus sources, retention and export to the East China Sea and Yellow Sea.

    Science.gov (United States)

    Liu, Xiaochen; Beusen, Arthur H W; Van Beek, Ludovicus P H; Mogollón, José M; Ran, Xiangbin; Bouwman, Alexander F

    2018-06-04

    Nitrogen (N) and phosphorus (P) flows from land to sea in the Yangtze River basin were simulated for the period 1900-2010, by combining models for hydrology, nutrient input to surface water, and an in-stream retention. This study reveals that the basin-wide nutrient budget, delivery to surface water, and in-stream retention increased during this period. Since 2004, the Three Gorges Reservoir has contributed 5% and 7% of N and P basin-wide retention, respectively. With the dramatic rise in nutrient delivery, even this additional retention was insufficient to prevent an increase of riverine export from 337 Gg N yr -1 and 58 Gg P yr -1 (N:P molar ratio = 13) to 5896 Gg N yr -1 and 381 Gg P yr -1 (N:P molar ratio = 35) to the East China Sea and Yellow Sea (ECSYS). The midstream and upstream subbasins dominate the N and P exports to the ECSYS, respectively, due to various human activities along the river. Our spatially explicit nutrient source allocation can aid in the strategic targeting of nutrient reduction policies. We posit that these should focus on improving the agricultural fertilizer and manure use efficiency in the upstream and midstream and better urban wastewater management in the downstream subbasin. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. 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.

  3. Spatio-temporal patterns of Ulva prolifera blooms and the corresponding influence on chlorophyll-a concentration in the Southern Yellow Sea, China.

    Science.gov (United States)

    Sun, Xiao; Wu, Mengquan; Xing, Qianguo; Song, Xiaodong; Zhao, Deheng; Han, Qianqian; Zhang, Guangzong

    2018-06-04

    The world's largest macroalgal blooms (MABs) caused by the Ulva prolifera outbreaks have occurred every summer since 2007 in the Southern Yellow Sea, China. Accumulating evidence showed that MABs may deteriorate the regional marine environment and influence the growth of some primary producers such as phytoplankton. In this study, we investigated the spatio-temporal patterns of U. prolifera green tides and chlorophyll-a concentration in the Southern Yellow Sea in 2015 using satellite images obtained from HJ-1 CCD, MODIS, and GOCI. The correlation between the distributions of U. prolifera abundance and chlorophyll-a concentration was analyzed quantitatively by setting up a series of 5 × 5 km experimental grids, and we also discussed the possible mechanisms about the influence of U. prolifera blooms on the other floating microalgae. The results showed that the development of U. prolifera blooms in the Southern Yellow Sea in 2015 could be featured as "appearance - development - outbreak - decline - disappearance", while the concentration of chlorophyll-a showed "increase - sharp decline - slow recovery - stabilization" from April to August. We also found that the concentration of chlorophyll-a had the following relationships with U. prolifera temporally: (1) the concentration of chlorophyll-a increased with the growth of U. prolifera from April to mid-May; (2) the chlorophyll-a concentration decreased sharply with the dramatically increased coverage of U. prolifera in June; and (3) the chlorophyll-a concentration slowly recovered and finally stabilized as U. prolifera decreased in July. Generally, there was a negative correlation between the occurrence of U. prolifera and chlorophyll-a concentration in the Southern Yellow Sea, China. Our results showed that the outbreak of U. prolifera does have a certain impact on the growth and reproduction of planktonic microalgae, and it suggests that U. prolifera blooms have potentially altered the ecological balance in

  4. Sources and distribution of polychlorinated-dibenzo-p-dioxins and -dibenzofurans in soil and sediment from the Yellow Sea region of China and Korea

    International Nuclear Information System (INIS)

    Naile, Jonathan E.; Khim, Jong Seong; Wang Tieyu; Wan Yi; Luo Wei; Hu Wenyou; Jiao Wentao; Park, Jinsoon; Ryu, Jongseong; Hong, Seongjin; Jones, Paul D.; Lu Yonglong

    2011-01-01

    Polychlorinated-dibenzo-p-dioxins and -dibenzofurans (PCDD/Fs) were measured in soils and sediments from the Yellow Sea region. Korean soils and sediments mostly contained detectable PCDD/Fs and showed a widespread distribution among locations. Soil and sedimentary PCDD/Fs from China were comparable to or less than those in Korea. The patterns of relative concentrations of individual congeners in soils were different between the two countries, but similar in sediments. Sources of PCDD/Fs in China and Korea were found to be independent of each other and their distributions reflected matrix-dependent accumulation. Spatial distribution indicated some point sources in Korea while Chinese sources were more widespread and diffuse. PCDD/Fs measured in the coastal areas of the Yellow Sea were comparable to or less than those previously reported in for eastern Asia. However, ΣTEQs in soils and sediments were near to or, in some cases exceeded environmental quality guidelines. - Research highlights: → PCDDs were comparable or greater than PCDFs for Yellow Sea soils and sediments. → PCDD/Fs congener patterns in soils were different but similar in sediments. → PCDD/Fs congener patterns varied among regions reflecting regional activities. → Sources of PCDD/Fs in China and Korea were mainly independent of each other. → ΣTEQs in Yellow Sea soils and sediments often exceeded corresponding guidelines. - PCDD/Fs in soils and sediments along the Yellow Sea indicated both point and non-point sources and their contribution to total TEQs differed among land uses and by regional activities.

  5. The continuing investment attraction af the North Sea to a large oil company

    International Nuclear Information System (INIS)

    Bijur, P.

    1992-01-01

    The North Sea is a success story of a partnership between government and industry in which everyone is winning. This paper considers what it will take to keep the success story going - to keep the North Sea attractive to large investors. First, the most significant of the future challenges facing investors here are outlined -competing investments, declining prospectivity and technical barriers. Some positive recommendations follow that may enable the oil industry to overcome the challenges and keep the North Sea a centre for petroleum investment into the next century. (author)

  6. Distributions of freak wave heights measured in the North Sea

    International Nuclear Information System (INIS)

    Stansell, P.

    2004-01-01

    We present a statistical analysis of some of the largest waves occurring during 793 h of surface elevation measurements collected during 14 severe storms in the North Sea. This data contains 104 freak waves. It is found that the probability of occurrence of freak waves is only weekly dependent on the significant wave height, significant wave steepness and spectral bandwidth. The probability does show a slightly stronger dependency on the skew and kurtosis of the surface elevation data, but on removing the contribution to these measures from the presence of the freakwaves themselves, this dependency largely disappears. Distributions of extreme waves are modelled by fitting Generalised Pareto distributions, and extreme value distributions and return periods are given for freak waves in terms of the empirical fitted parameters. It is shown by comparison with these fits that both the Rayleigh distribution and the fit of Nerzic and Prevosto severely under-predict the probability of occurrence of extreme waves. For the most extreme freak wave in our data, the Rayleigh distribution over-predicts the return period by about 300 times when compared to the fitted model. (author)

  7. Britain's North Sea oil and gas production: a critical review

    International Nuclear Information System (INIS)

    Odell, P.R.

    1996-01-01

    The size and longevity of Britain's offshore hydrocarbons resources have been underestimated. Gas reserves were seriously under-exploited for almost 20 years from the late 1960s, given a belief that gas should be used only as a premium fuel and in the context of an uncompetitive market. Oil reserves' development and production has suffered from time to time from inappropriate politico-economic conditions. Nevertheless, offshore oil and gas has come to dominate the UK's energy production over the past 20 years and currently accounts for 85% of the country's total energy output. Fears for resources' exhaustion remain unjustified, as the industry continues to replace oil and gas reserves used each year. The North Sea is still not comprehensively explored: the continuation of the process will enable oil production to remain at high levels and that of gas to expand further. Supplementary output from the new west of Shetland province will become progressively more important after 2000. But continued intensive production overall depends on the maintenance of attractive politico-economic conditions and on present oil prices. It also requires the European gas market to remain firm but, ironically, the planned flow of UK gas to the mainland constitutes a threat to this condition. (Author)

  8. Exchange of polycyclic aromatic hydrocarbons across the air-water interface in the Bohai and Yellow Seas

    Science.gov (United States)

    Chen, Yingjun; Lin, Tian; Tang, Jianhui; Xie, Zhiyong; Tian, Chongguo; Li, Jun; Zhang, Gan

    2016-09-01

    In this study, air and surface seawater samples collected from the Bohai (BS) and Yellow Seas (YS) in May 2012 were determined exchange of PAHs, especially of low-molecular-weight (LMW) PAHs (three- and four-ring PAHs) at the air-water interface. Net volatilization fluxes of LMW PAHs were 266-1454 ng/m2/d and decreased with distance from the coast, indicating that these PAHs transported from coastal runoff were potential contributors to the atmosphere in the BS and YS. Moreover, LMW PAHs were enriched in the dissolved phase compared with those in the particulate phase in the water column, possibly suggesting that the volatilized LMW PAHs were directly derived from wastewater discharge or petroleum pollution rather than released from contaminated sediments. The air-sea exchange fluxes of the three-ring PAHs were 2- to 20-fold higher than their atmospheric deposition fluxes in the BS and YS. The input to and output from the water reached equilibrium for four-ring PAHs. Differently, five- and six-ring PAHs were introduced into the marine environment primarily through dry and wet deposition, indicating that the water column was still a sink of these PAHs from the surrounding atmosphere.

  9. Chemical characterization of fractions of dissolved humic substances from a marginal sea—a case from the Southern Yellow Sea

    Science.gov (United States)

    Zhang, Yaoling; Yang, Keli; Du, Jinzhou; Zhang, Fenfen; Dong, Yaping; Li, Wu

    2018-03-01

    Marine dissolved organic matter (DOM) is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances (DHS) were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids (FAs), humic acids (HAs) and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy (FTIR), 13C cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.

  10. Spatial variation of biogenic sulfur in the south Yellow Sea and the East China Sea during summer and its contribution to atmospheric sulfate aerosol.

    Science.gov (United States)

    Zhang, Sheng-Hui; Yang, Gui-Peng; Zhang, Hong-Hai; Yang, Jian

    2014-08-01

    Spatial distributions of biogenic sulfur compounds including dimethylsulfide (DMS), dissolved and particulate dimethylsulfoniopropionate (DMSPd and DMSPp) were investigated in the South Yellow Sea (SYS) and the East China Sea (ECS) in July 2011. The concentrations of DMS and DMSPp were significantly correlated with the levels of chlorophyll a in the surface water. Simultaneously, relatively high ratio values of DMSP/chlorophyll a and DMS/chlorophyll a occurred in the areas where the phytoplankton community was dominated by dinoflagellates. The DMSPp and chlorophyll a size-fractionation showed that larger nanoplankton (5-20 μm) was the most important producer of DMSPp in the study area. The vertical profiles of DMS and DMSP were characterized by a maximum at the upper layer and the bottom concentrations were also relatively higher compared with the overlying layer of the bottom. In addition, a positive linear correlation was observed between dissolved dimethylsulfoxide (DMSOd) and DMS concentrations in the surface waters. The sea-to-air fluxes of DMS in the study area were estimated to be from 0.03 to 102.35 μmol m(-2) d(-1) with a mean of 16.73 μmol m(-2) d(-1) and the contribution of biogenic non-sea-salt SO4(2-) (nss-SO4(2-)) to the measured total nss-SO4(2-) in the atmospheric aerosol over the study area varied from 1.42% to 30.98%, with an average of 8.2%. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Spatial differences in growth of lesser sandeel in the North Sea

    DEFF Research Database (Denmark)

    Rindorf, Anna; Wright, Peter J.; Jensen, Henrik

    2016-01-01

    Lesser sandeel, Ammodytes marinus, is a key prey to a variety of North Sea predators, including species such as single load seabirds which are highly sensitive to prey size and condition. Whilst differences in weight at age across the North Sea have been investigated previously, the scale and cause...... of this variation as well as the potential link to spatial differences in predator performance remains unknown. This study presents an analysis of spatial patterns in length and condition of the lesser sandeel in the North Sea and the relationship of these with physical and biological factors. Both mean length...... considerably both spatially and temporally, resulting in 4 fold and 1.9 fold variations in the number of sandeels required to obtain a specific weight, respectively. Hence, the value of sandeel as prey to single load predators varies considerably with values in central and northeastern North Sea being...

  12. Impacts of sea cucumber farming on biogeochemical characteristics in the Yellow River estuary, Northern China

    Science.gov (United States)

    Fu, Jing; Yokoyama, Hisashi; Cui, Baoshan; Zhou, Jin; Yan, Jiaguo; Ma, Xu; Shibata, Shozo

    2017-02-01

    To investigate the potential environmental effects of pond farming for Apostichopus japonicas in Yellow River estuary, we examined discrepancies of distance-based typical pollution indicators (TOC, TN, NO3-, NH4+, NO2- and PO43-) and biochemical tracers (δ13C and δ15N) in water column and sediment, as well as dietary characteristics of dominant macrobenthos between farming and non-farming areas. The results revealed that studied variables in water column showed no uniform spatial differences. Meanwhile, those in sediment displayed similar decrease tendencies from farming pond to the adjacent tidal flat, which was considered to represent the environmental effects of farming. Biochemical tracers (δ13C and δ15N) in both water column and sediment confirmed the origin of organic matters from the aquaculture waste. The detectable dispersion distance of aquaculture waste was restricted to an area within 50 m distance as determined by most variables in sediment (TOC, TN, NO3- and NH4+), particularly by C:N ratio and δ13C with which origins of the wastes were traced. Bayesian mixing models indicated that in the farming area BMA had a larger contribution, while POM(marine) showed a smaller contribution to the diets of Helice tridens and Macrophthalmus abbreviates compared to those in the non-farming area. The overall results showed that pond farming for Apostichopus japonicus in the Yellow River estuary altered the local environment to a certain extent. For methodological consideration, sediment biogeochemical characteristics as a historical recorder much more effectively reflected aquaculture waste accumulation, and stable isotope approaches are efficient in tracing the origin and extent of various allogenous sources.

  13. Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

    Science.gov (United States)

    Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

    2017-12-31

    Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and

  14. Spatial distributions and deposition chronology of short chain chlorinated paraffins in marine sediments across the Chinese Bohai and Yellow Seas.

    Science.gov (United States)

    Zeng, Lixi; Chen, Ru; Zhao, Zongshan; Wang, Thanh; Gao, Yan; Li, An; Wang, Yawei; Jiang, Guibin; Sun, Liguang

    2013-10-15

    As the most complex halogenated contaminants, short chain chlorinated paraffins (SCCPs) are scarcely reported in marine environments. In this work, a total of 117 surficial sediment (0-3 cm) samples and two sediment cores were collected from the Chinese Bohai and Yellow Seas to systematically study the spatial and temporal trends of SCCPs at a large scale in the Chinese marine environment. Total SCCP concentrations in the surficial sediments were in the range of 14.5-85.2 ng g(-1) (dry weight, d.w.) with an average level of 38.4 ng g(-1) d.w. Spatial distribution showed a decreasing trend with the distance from the coast to the open waters. Compositional pattern analysis suggested that C10 was the most predominant homologue group, followed by C11, C12, and C13 homologue groups. The concentrations of total SCCPs in sediment cores ranged from 11.6 to 94.7 ng g(-1) d.w. for YS1 and from 14.7 to 195.6 ng g(-1) d.w. for YS2, with sharp rise from the early 1950s to present based on (210)Pb dating technique. The historical records in cores correspond well to the production and usage changes of CPs in China. Multivariate regression statistics indicate TOC, latitude and longitude are the major factors influencing surficial SCCP levels in the Chinese East Seas by combining analysis with the data from the East China Sea (R(2) = 0.332, p < 0.01). These findings indicated that the sources of SCCPs were mainly from river outflows via ocean current and partly from atmospheric depositions by East Asian monsoon in the sampling areas.

  15. Flux and distribution of methane (CH4) in the Gunsan Basin of the southeastern Yellow Sea, off the Western Korea.

    Science.gov (United States)

    Lee, Jun-Ho; Woo, Han Jun; Son, Seung-Kyu; Kim, Moonkoo; Lee, Dong-Hun; Tsunogai, Urumu; Jeong, Kap-Sik

    2018-04-16

    The flux and distribution of methane (CH 4 ) was investigated in the seawater column at 14 stations in the Gunsan Basin, the southeastern part of Yellow Sea from 2013 to 2015. Here CH 4 is concentrated 2.4-4.7 (3.4 ± 0.7) nM in the surface and 2.5-7.4 (5.2 ± 1.7) nM in the bottom layer. The CH 4 saturation ratios ranged from 65.5% to 295.5% (162.6 ± 68.7), comprising the mean sea-to-air CH 4 flux of 3.8 to 25.3 (15.6 ± 5.5) µM m -2 d -1 . Methane concentration was largely different in the upper and the lower seawater layers that is separated by the thermocline of which depth is variable (20-60 m) depending on the time of sampling. The concentration of seawater dissolved CH 4 is high between the bottom surface of the thermocline layer and the sea floor. Generally it tends to decrease from the south-westernmost part of the basin toward the west coast of Korea. This distribution pattern of CH 4 seems to result from the CH 4 supply by decomposition of organic matters produced in the upper seawater layer that is superimposed by the larger supply from the underlying sediment layer especially beneath the thermocline. The latter is manifested by ubiquitous CH 4 seeps from the seafloor sediments.

  16. Dispersion of radionuclides in the European north-western seas: observations and modelling

    International Nuclear Information System (INIS)

    Bailly du Bois, Pascal

    2013-01-01

    In this report for an Accreditation to supervise research (HDR), the author reports the use over 30 years by the Cherbourg-Octeville IRSN Laboratory of artificial radionuclides in solution in sea water as oceanographic markers. Such measurements on radio-markers which are soluble in sea water, enabled a better knowledge of dissolved substance displacements in north-western seas of Europe, notably the Channel, the North Sea, the Celtic Sea, and the Irish Sea. The author reports researches which aimed at studying the dispersion of radionuclides in seawater and their use as water mass markers, at validating hydrodynamic models of dispersion at different time-space scales, at the understanding and simulation of the sedimentary transport, and at studying the transfer to living species. These different topics give the document its structure [fr

  17. Chemical and temperature profile data from CTD casts in the East China Sea, Sea of Japan, and North Pacific Ocean (NODC Accession 9700022)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical and temperature profile data were collected from CTD casts in the East China Sea, Sea of Japan, and North Pacific Ocean. Data were submitted by the Japan...

  18. Productivity, facies and stable-isotope records of OAE2 (Cenomanian - Turonian) in the NW European epicontinental sea: from the English Chalk to North Sea black shales

    Science.gov (United States)

    Jarvis, Ian; Olde, Kate; Trabucho-Alexandre, João; Gröcke, Darren

    2013-04-01

    The Late Cretaceous (100.5 - 66.0 Ma) provides perhaps the best example of how the Earth System may function under long-term extreme greenhouse conditions. Rapidly rising global temperatures indicate that we are heading 'back to the Cretaceous' within a few hundred years, so a better understanding of this time interval is essential. The beginning of the Late Cretaceous was characterized by a period of rapidly rising eustatic sea level, the Cenomanian transgression, which flooded continental margins and established large areas of new epicontinental sea that accumulated thick sequences of pelagic and hemipelagic carbonate (chalk). Highest global temperatures were reached during the early part of the Turonian Stage (93.9 - 89.8 Ma). This period of dramatic palaeoenvironmental change was accompanied by one the largest perturbations of the global carbon cycle in the Mesozoic: Oceanic Anoxic Event 2 (OAE2), which was characterized by a 500 kyr episode of oceanic anoxia, widespread black shale deposition, biotic turnover, and a large global positive carbon stable-isotope excursion (2 - 6 ‰ ∂13C) recorded in marine carbonates and both marine and terrestrial organic matter. The Cenomanian-Turonian boundary interval exposed at Eastbourne, southern England, has become established as a European reference section for OAE2. Here, and elsewhere in Europe, the base of the ∂13C excursion is coincident with a marked facies change from rhythmically bedded grey chalks and marls, to a >8 m thick package of dark greenish-grey marl - the Plenus Marl. The termination of OAE2 occurs 6 m above, in a package of pale-yellow-weathering nodular chalks with prominent marl seams. Sediments are organic lean (10 wt%. The onshore equivalent in eastern England (the Black Band) is similarly organic-rich, as are comparable sections in northern Germany (e.g. Wunstorf), indicating likely fully anoxic episodes within some NW European basins. The exact stratigraphic equivalence between the onshore

  19. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    Haas, H. de

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (C02 ) is one of the major contributors to the natural greenhouse

  20. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    de Haas, H.

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (CO2 ) is one of the major contributors to the natural greenhouse

  1. A Triple P review of the feasibility of sustainable offshore seaweed production in the North Sea

    NARCIS (Netherlands)

    Burg, van den S.W.K.; Stuiver, M.; Veenstra, F.A.; Bikker, P.; Lopez Contreras, A.M.; Palstra, A.P.; Broeze, J.; Jansen, H.M.; Jak, R.G.; Gerritsen, A.L.; Harmsen, P.F.H.; Kals, J.; Blanco Garcia, A.; Brandenburg, W.A.; Krimpen, van M.M.; Duijn, van A.P.; Mulder, W.J.; Raamsdonk, van L.W.D.

    2013-01-01

    This study focused on the potential of seaweed, cultivated in the North Sea, as a sustainable and profitable resource for feed and non-food applications. Seawood production can take place as part of multi-use platforms at sea (MUPS). A review of the state-of-the-art in seaweed production and its

  2. Investigation of a North Sea oil platform drill cuttings pile

    International Nuclear Information System (INIS)

    Hartley, J.P.; Watson, T.N.

    1993-01-01

    A comprehensive study of the drill cuttings pile at North West Hutton was undertaken in August, 1992. Fifty one wells have been drilled in the field, mainly using mineral oil based drill fluids, with the cuttings discharged to sea. The cuttings pile was mapped using a 3D side scan sonar system and the periphery was defined by towed side scan sonar and gamma ray spectrometer surveys. The pile was cored by vibrocorer to a maximum depth of 2.35m. The cores were assessed geotechnically and subsampled for physical and chemical analyses. Environmental impact was investigated by grab sampling at 12 stations out to 7,500m, selected on the basis of cuttings distribution. The results are relevant to the corrosion and long-term environmental effects of oily cuttings piles, the remove/leave alone debate, and abandonment planning. The cores were subsampled for hydrocarbon, trace metals and sulphide content and grain size analysis. Metals analyses included identification of metal species to estimate bioavailability and implications of pile disturbance. Estimates of oil migration within the pile are made from correlation of the chemical analyses results with the drilling history, in particular the change from diesel to low toxicity base oil in 1984. Strong gradients were found in the faunal data which correlate well with the physical and chemical results. Dense populations of opportunists species were present adjacent to the platform, including a novel molluscan opportunist. This is the first comprehensive study of an oily cuttings pile and is a contribution to the debate on their long term impact and fate on abandonment

  3. Space weather effects on drilling accuracy in the North Sea

    Directory of Open Access Journals (Sweden)

    S. J. Reay

    2005-11-01

    Full Text Available The oil industry uses geomagnetic field information to aid directional drilling operations when drilling for oil and gas offshore. These operations involve continuous monitoring of the azimuth and inclination of the well path to ensure the target is reached and, for safety reasons, to avoid collisions with existing wells. Although the most accurate method of achieving this is through a gyroscopic survey, this can be time consuming and expensive. An alternative method is a magnetic survey, where measurements while drilling (MWD are made along the well by magnetometers housed in a tool within the drill string. These MWD magnetic surveys require estimates of the Earth's magnetic field at the drilling location to correct the downhole magnetometer readings. The most accurate corrections are obtained if all sources of the Earth's magnetic field are considered. Estimates of the main field generated in the core and the local crustal field can be obtained using mathematical models derived from suitable data sets. In order to quantify the external field, an analysis of UK observatory data from 1983 to 2004 has been carried out. By accounting for the external field, the directional error associated with estimated field values at a mid-latitude oil well (55° N in the North Sea is shown to be reduced by the order of 20%. This improvement varies with latitude, local time, season and phase of the geomagnetic activity cycle. By accounting for all sources of the field, using a technique called Interpolation In-Field Referencing (IIFR, directional drillers have access to data from a "virtual" magnetic observatory at the drill site. This leads to an error reduction in positional accuracy that is close to matching that of the gyroscopic survey method and provides a valuable independent technique for quality control purposes.

  4. Scottish Sea Lochs: High Resolution Archives of North Atlantic Climate

    Science.gov (United States)

    Norgaard-Pedersen, N.; Austin, W. E.; Cage, A. G.; Shimmield, T. M.; Gillibrand, P. A.

    2002-12-01

    The sea lochs (fjords) of NW Scotland bridge the land-ocean interface in a region of Europe which is particularly well situated to monitor changes in westerly air flow. Inter-annual atmospheric circulation changes at this latitude are largely governed by the North Atlantic Oscillation (NAO), in turn influencing both westerlies and precipitation. Comparing two extreme recent NAO years, circulation modelling results from Loch Sunart, NW Scotland, reveal a clear response to freshwater runoff and wind forcing in both magnitude and rate of deep-water renewal events. Scottish fjords, because of the relatively small impact which salinity has on d18Owater (0.18 % per salinity unit), potentially provide NW Europe's most useful study sites in coastal palaeoclimate research, particularly where palaeotemperature is the primary record of interest. New data from a high-resolution record (7 yr sample resolution), spanning the last two millennia, from the deepest part of the main basin of Loch Sunart illustrate significant multi-decadal to centennial scale variability in the sedimentary and stable isotope record of epibenthic foraminifera Cibicides lobatulus. The long-term pattern in benthic d18O appears to reflect bottom water temperature differences of 1-2§C, resolving climatic periods such as the Medieval Warm Period and the Little Ice Age. Since the core site is connected with shelf waters (i.e. no shallow sill) it seems likely that this paleotemperature reflects changing shelf water, not the exchange process as a function of long-term runoff/wind forcing. Grain size data and XRF data point to catchment-wide responses (weathering and erosion) which appear to show the largest variability during the last millennium, driven either by rainfall and temperature and/or land-use. Pb-isotope data, constraining the modern and industrial period, suggest accelerated sedimentation rates over this interval. On-going work attempts to calibrate proxy data with instrumental historical data.

  5. Ecological divergence in the yellow-bellied kingsnake (Lampropeltis calligaster) at two North American biodiversity hotspots.

    Science.gov (United States)

    McKelvy, A D; Burbrink, F T

    2017-01-01

    Several biogeographic barriers in the Eastern Nearctic appear to reduce gene flow among populations of many species in predictable ways, however these patterns used to infer process of divergence may be deceiving if alternative modes of diversification are not considered. By using a multilocus statistical phylogeographic approach to examine diversity within a North American snake, Lampropeltis calligaster, we find that mode and timing of speciation near the Mississippi River embayment and peninsular Florida, two main biodiversity hotspots in eastern North America, challenge previously held notions of strict vicariance as the causal factor behind patterns of divergence seen among taxa at these locations. We found three species inhabiting distinct ecological niches with divergences dating to the mid- and early-Pleistocene with subsequently stable or increasing effective population sizes, further supporting the idea that the Pleistocene was an important driver of diversification in North America. Our results lead to a revised hypothesis that ecological divergence has occurred in this group across environments associated with the Mississippi River and at the Florida peninsula. Importantly, in their western distributions, we show that species divergence is associated with the ecological transition from distinct forested habitats to grasslands, rather than the nearby Mississippi River, a barrier often implicated for many other organisms. Additionally, we stress the importance of examining each delimited lineage with respect to conservation, since ecological niche models suggest that by the end of the century changes in climate may negatively alter habitat suitability and, barring adaptation, substantially reduce the suitable range of two of the three species we identified. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Polyunsaturated fatty acids in various macroalgal species from north Atlantic and tropical seas

    OpenAIRE

    van Ginneken, Vincent JT; Helsper, Johannes PFG; de Visser, Willem; van Keulen, Herman; Brandenburg, Willem A

    2011-01-01

    Abstract Background In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated. Methods The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (...

  7. Hourly to Decadal variability of sea surface carbon parameters in the north western Mediteranean Sea

    Science.gov (United States)

    Boutin, Jacqueline; Merlivat, Liliane; Antoine, David; Beaumont, Laurence; Golbol, Melek; Velluci, Vincenzo

    2017-04-01

    Sea surface CO2 fugacity, fCO2, is recorded hourly in the north western Mediterranean Sea since 2013 by two CARIOCA (Carbon Interface Ocean Atmosphere) sensors installed on the BOUSSOLE (Buoy for the acquisition of long term optical time series, http://www.obs-vlfr.fr/Boussole/html/project/introduction.php) mooring at 3m and 10m depth. fCO2 exhibits a large seasonal cycle, about 150 microatm peak to peak, very consistent with earlier CARIOCA measurements taken in 1995-1999 at the DYFAMED site (located 6km apart from the BOUSSOLE mooring) (Hood and Merlivat, JMR, 2001; Copin-Montegut et al., Mar. Chem., 2004): this seasonal cycle is driven primarily by intense mixing in Winter, biological uptake during Spring and warming during Summer. Interannual variability of these processes leads to interannual variability of monthly mean fCO2 that can reach more than 20 microatm. The short term variability (1 hour to 1 week) is large, especially during Summer 2014 (more than 40 microatm) due to a very strong vertical stratification and to the influence of internal waves. The hourly CARIOCA measurements allow to correctly filter out the high frequency variability while the three year long time series allow to smooth out interannual variability. Hence, for the first time, we get a precise estimate of the change of fCO2 in surface waters within 20 years. Over the 1995-2015 interval, we estimate an increase of fCO2 computed at a constant temperature of 13˚ C equal to 1.8 microatm per year. Given the alkalinity/salinity relationship in this region, we estimate mean annual rates of change of -0.0023+/-0.0001 pH unit and of +1.47+/-0.03 μmol kg-1 for pH and DIC respectively. These results give a quantitative estimate of the penetration of anthropogenic carbon in the surface waters of the northwestern Mediterranean Sea, about 80% via air-sea exchange and 20% via transport of carbon from the Atlantic across the Strait of Gibraltar as suggested by Palmieri et al (BG, 2015). We estimate

  8. Phosphorus binding by poorly crystalline iron oxides in North Sea sediments

    NARCIS (Netherlands)

    Slomp, C.P.; Gaast, S. J. van der; Raaphorst, W. van

    1996-01-01

    Differential X-ray powder diffraction (DXRD) and extraction procedures were used to characterize the iron oxides present in four sediments from contrasting environments in the North Sea. Stations were located in depositional areas on the southern shelf (German Bight) and on the north-eastern

  9. Regional cenozoic uplift and subsidence events in the southeastern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Jordt, H.

    1995-12-31

    The Paleocene topography of the Fennoscandian Shield is indicated by outbuilding towards the Central Trough and the Ringkoebing-Fyn High. From Eocene until Pliocene time three events of relative vertical movements are indicated by changes in outbuilding directions and reflection termination patterns in the central North Sea. The firs event of uplift was in the Eocene and resulted in relative uplift of the Mid North Sea High and contemporary subsidence east of it, indicated by a change in outbuilding from north to west. A second event of uplift is indicated to the north of the study area at the Eocene-Oligocene boundary by renewed southward outbuilding in the Norwegian-Danish Basin. In Miocene until Early Pliocene time a relatively stationary, almost east-west striking, basin margin was probably located to the north along the Tornquist Zone as indicated by the continued outbuilding towards the Ringkoebing-Fyn High. A third event of relative uplift is indicated east of the study area by changes in the Pliocene outbuilding pattern. After the first event of uplift it appears that the deepest parts of the Eocene North Sea Basin was located more easterly than the deepest part are today. Apparently the two latest uplift events north and east of the study area were related to movements of, or along the Tornquist Zone or to regional uplift of the Fennoscandian Shield finally resulting in the present-day configuration of the North Sea. (au) 11 refs.

  10. Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

    Directory of Open Access Journals (Sweden)

    M. Wary

    2017-06-01

    Full Text Available Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.

  11. Exploration and development of offshore oil and gas fields. [North Sea

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    In the last 9 years, the British companies, based on their rich engineering and commercial experience, have directed a considerable part of their material and manpower resources at developing oil and gas fields in the North Sea. The technological innovations used by British industry are: aero- and marine surveys to prospect for oil, underwater laying of pipelines, arrangement of platforms, etc.; exploratory drilling in the open sea and on dry land; design of platforms with regard for the depth of the water and unique weather conditions of the North Sea, their assembly and development; use of auxiliary ships and helicopters, and diving equipment.

  12. [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 recruitment 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

  13. Palaeoenvironmental changes across the Danian–Selandian boundary in the North Sea Basin

    DEFF Research Database (Denmark)

    Clemmensen, Anne; Thomsen, Erik

    2005-01-01

    cores from Storebælt in the eastern part of the North Sea Basin, we have reconstructed the palaeoenvironmental changes across the boundary. The benthic foraminiferal faunas belong to the “Midway-type fauna”. They are extremely rich and more than 260 taxa have been recognized. Q-mode cluster analysis......, the sea bottom conditions became colder and more acidic. This resulted in partial dissolution of the carbonates and the deposition shifted from marl to clay. Comparison with records from the Western Pyrenees, the Nile Basin and the eastern North America suggests that sea-level changes across the Danian......The Danian–Selandian boundary (not, vert, similar60 Ma) marks the cessation of 40 million years of carbonate deposition in the North Sea Basin and a shift to siliciclastic deposition. On the basis of variations in lithology, benthic and planktonic foraminifera and calcareous nannofossils in three...

  14. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    Directory of Open Access Journals (Sweden)

    D. Neumann

    2016-03-01

    Full Text Available Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ modeling system and are compared to European Monitoring and Evaluation Programme (EMEP measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 +  NH4+ and HNO3 +  NO3− and a decrease in NO3− concentrations. However, the overall effect on NH3 +  NH4+ and HNO3 +  NO3− concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is

  15. A decision support system for assessing offshore wind energy potential in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Wanderer, T.; Schillings, C. [German Aerospace Center (DLR), Systems Analysis and Technology Assessment, Stuttgart (Germany); Cameron, L.; Veum, K. [Energy research Center of the Netherlands ECN, Policy Studies Department, Amsterdam (Netherlands); Tjalling van der Wal, J. [IMARES, Wageningen UR, Den Helder (Netherlands); Jacquemin, J. [GL Garrad Hassan, Paris (France)

    2012-10-15

    Offshore wind energy (OWE) in the North Sea has the potential to meet large share of Europe's future electricity demand. To deploy offshore wind parks in a rational way, the overall OWE potential has to be realistically determined. This has to be done on an international, cross-border level and by taking into account the existing man-made and nature-related uses of the North Sea. As spatial conflicts will arise between existing uses and the new OWE uses, a Decision Support System (DSS) based on a Geographic Information System (GIS) was developed. Based on data of existing sea uses and calculation rules for spatial prioritisation analysis, the DSS helps in identifying areas that are (1) generally suitable for offshore wind power, (2) strictly excluded or (3) negotiable with respect to other existing sea uses. The combination of this conflict analysis together with cost assumptions for offshore wind farms and their expected electricity yield leads to identification of favourable areas for OWE deployment in the North Sea. This approach helps to reduce the conflict between offshore wind deployment and existing sea uses in the North Sea for future planning. The results can assist decision makers in developing transnational roadmaps for OWE.

  16. The status of coastal oceanography in heavily impacted Yellow and East China Sea: Past trends, progress, and possible futures

    Science.gov (United States)

    Wang, Xiao Hua; Cho, Yang-Ki; Guo, Xinyu; Wu, Chau-Ron; Zhou, Junliang

    2015-09-01

    Coastal environments are a key location for transport, commercial, residential and defence infrastructure, and have provided conditions suitable for economic growth. They also fulfil important cultural, recreational and aesthetic needs; have intrinsic ecosystem service values; and provide essential biogeochemical functions such as primary productivity, nutrient cycling and water filtration. The rapid expansion in economic development and anticipated growth of the population in the coastal zones along the Yellow and East China Sea basin has placed this region under intense multiple stresses. Here we aim to: 1) synthesize the new knowledge/science in coastal oceanography since 2010 within the context of the scientific literature published in English; 2) report on a citation analysis that assesses whether new research topics have emerged and integrated over time, indicate the location of modelling and field-based studies; and 3) suggest where the new research should develop for heavily impacted estuaries and coastal seas of East Asia. The conclusions of the synthesis include: 1) China has emerged as a dominant force in the region in producing scientific literature in coastal oceanography, although the area of publications has shifted from its traditional fields such as physical oceanography; 2) there has been an increasing number of publications with cross-disciplinary themes between physical oceanography and other fields of the biological, chemical, and geological disciplines, but vigorous and systematic funding mechanisms are still lacking to ensure the viability of large scale multi-disciplinary teams and projects in order to support trans-disciplinary research and newly emerging fields; 3) coastal oceanography is responding to new challenges, with many papers studying the impacts of human activities on marine environment and ecology, but so far very few studying management and conservation strategies or offering policy solutions.

  17. Contrasting trends in North Atlantic deep-water formation in the Labrador Sea and Nordic Seas during the Holocene

    NARCIS (Netherlands)

    Renssen, H.; Goosse, H.; Fichefet, T.

    2005-01-01

    The Holocene North Atlantic deep-water formation is studied in a 9,000-year long simulation with a coupled climate model of intermediate complexity, forced by changes in orbital forcing and atmospheric trace gas concentrations. During the experiment, deep-water formation in the Nordic Seas is

  18. Improving the assessment and management of the plaice stock complex between the North Sea and the Baltic Sea

    DEFF Research Database (Denmark)

    Ulrich, Clara; Boje, Jesper; Cardinale, Massimiliano

    2012-01-01

    Plaice in Kattegat and Skagerrak have traditionally been considered as one stock unit. However the collected information on biology and fishery in areas between the North and Baltic Seas suggest changes are needed in assessment units as well as in management areas. Plaice in Skagerrak (Division 20...

  19. Connectivity of larval cod in the transition area between North Sea and Baltic Sea and potential implications for fisheries management

    DEFF Research Database (Denmark)

    Huwer, Bastian; Hinrichsen, H.-H.; Hüssy, Karin

    2016-01-01

    in the transition area between North Sea and Baltic were investigated to (i) determine long-term trends and variability in advective transport of larvae from spawning grounds to juvenile nursery areas, (ii) estimate the degree of exchange between different management areas, and (iii) compare the results...

  20. Inter Annual Variability of the Acoustic Propagation in the Yellow Sea Identified from a Synoptic Monthly Gridded Database as Compared with GDEM

    Science.gov (United States)

    2016-09-01

    resolution in SMG-WOD, and thus less data levels for such shallow water . A comprehensive collection of salinity images by years can be found in the...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words ) This research investigates the inter-annual acoustic variability in the Yellow Sea identified from...is a semi-enclosed basin located between China and Korea with a mean depth of 40m; acoustics are driven by shallow water dynamics and interaction with

  1. An operational search and rescue model for the Norwegian Sea and the North Sea

    Science.gov (United States)

    Breivik, Øyvind; Allen, Arthur A.

    A new operational, ensemble-based search and rescue model for the Norwegian Sea and the North Sea is presented. The stochastic trajectory model computes the net motion of a range of search and rescue objects. A new, robust formulation for the relation between the wind and the motion of the drifting object (termed the leeway of the object) is employed. Empirically derived coefficients for 63 categories of search objects compiled by the US Coast Guard are ingested to estimate the leeway of the drifting objects. A Monte Carlo technique is employed to generate an ensemble that accounts for the uncertainties in forcing fields (wind and current), leeway drift properties, and the initial position of the search object. The ensemble yields an estimate of the time-evolving probability density function of the location of the search object, and its envelope defines the search area. Forcing fields from the operational oceanic and atmospheric forecast system of The Norwegian Meteorological Institute are used as input to the trajectory model. This allows for the first time high-resolution wind and current fields to be used to forecast search areas up to 60 h into the future. A limited set of field exercises show good agreement between model trajectories, search areas, and observed trajectories for life rafts and other search objects. Comparison with older methods shows that search areas expand much more slowly using the new ensemble method with high resolution forcing fields and the new leeway formulation. It is found that going to higher-order stochastic trajectory models will not significantly improve the forecast skill and the rate of expansion of search areas.

  2. Virulence Profiles of Vibrio vulnificus in German Coastal Waters, a Comparison of North Sea and Baltic Sea Isolates

    Directory of Open Access Journals (Sweden)

    Nadja Bier

    2015-12-01

    Full Text Available Vibrio vulnificus is a halophilic bacterium of coastal environments known for sporadically causing severe foodborne or wound infections. Global warming is expected to lead to a rising occurrence of V. vulnificus and an increasing incidence of human infections in Northern Europe. So far, infections in Germany were exclusively documented for the Baltic Sea coast, while no cases from the North Sea region have been reported. Regional variations in the prevalence of infections may be influenced by differences in the pathogenicity of V. vulnificus populations in both areas. This study aimed to compare the distribution of virulence-associated traits and genotypes among 101 V. vulnificus isolates from the Baltic Sea and North Sea in order to assess their pathogenicity potential. Furthermore, genetic relationships were examined by multilocus sequence typing (MLST. A high diversity of MLST sequences (74 sequence types and differences regarding the presence of six potential pathogenicity markers were observed in the V. vulnificus populations of both areas. Strains with genotypes and markers associated with pathogenicity are not restricted to a particular geographic region. This indicates that lack of reported cases in the North Sea region is not caused by the absence of potentially pathogenic strains.

  3. Yellow Fever

    Science.gov (United States)

    ... Testing Vaccine Information Testing for Vaccine Adverse Events Yellow fever Vaccine Continuing Education Course Yellow Fever Home Prevention Vaccine Vaccine Recommendations Reactions to Yellow Fever Vacine Yellow Fever Vaccine, Pregnancy, & ... Transmission Symptoms, Diagnosis, & Treatment Maps Africa ...

  4. Historical record of lead accumulation and source in the tidal flat of Haizhou Bay, Yellow Sea: Insights from lead isotopes

    International Nuclear Information System (INIS)

    Zhang, Rui; Guan, Minglei; Shu, Yujie; Shen, Liya; Chen, Xixi; Zhang, Fan; Li, Tiegang

    2016-01-01

    In order to investigate the historical records of lead contamination and source in coastal region of Haizhou Bay, Yellow Sea, a sediment core was collected from tidal flat, dated by 210 Pb and 137 Cs. Lead and its stable isotopic ratios were determined. The profiles of enrichment factor (EF) and Pb isotope ratios showed increasing trend upward throughout the core, correlating closely with the experience of a rapid economic and industrial development of the catchment. According to Pb isotopic ratios, coal combustion emission mainly contributed to the Pb burden in sediments. Based on end-member model, coal combustion emission dominated anthropogenic Pb sources in recent decades contributing from 48% to 67% in sediment. And the contribution of leaded gasoline was lower than 20%. A stable increase of coal combustion source was found in sediment core, while the contribution of leaded gasoline had declined recently, with the phase-out of leaded gasoline in China. - Highlights: •Pb contamination in tidal flat of Haizhou Bay was chronicled by a sediment core. •The coal combustion source dominated Pb contamination of Haizhou Bay. •Coal combustion source showed an increasing trend in four decades in Haizhou Bay.

  5. Ecological and taphonomical influences on coccoliths in surface sediments in the shelf of the Yellow and East China Seas

    Science.gov (United States)

    Jin, Xiaobo; Liu, Chuanlian

    2017-05-01

    Coccoliths, combined with sediment grain size, carbonate calcium and organic matters content, were analyzed to assess the ecological and taphonomical influences on coccolith distribution patterns in surface sediments in the continental shelf of the Yellow and East China Seas. Coccolith abundances ranged from 0 to 2.08×109 coccoliths g-1 sediment. The increasing abundance from the coastal inner shelf to the seaward middle shelf generally reflects the ecological fact that living coccolithophores are more abundant in the mesotrophic shelf waters than in the eutrophic coastal waters, although their deposits are still controlled by taphonomical effects, such as bottom (tidal) currents and calcite preservation conditions. Most abundant coccoliths are found in the fine-grained sediments of southwestern Cheju Island, where both ecology and taphonomy favor coccolith preservation. Still, large densities of coccoliths (>108 coccoliths g-1 sediment) are also found in coarse-grained relict sediments in the middle shelf. Coccolith assemblages were predominated by Gephyrocapsa oceanica and Emiliania huxleyi. The relative abundance of E. huxleyi, in addition to ecological reasons, may relate to selective post-mortem dissolution, since small E. huxleyi coccoliths are more susceptible to dissolution. Coccolith calcite has minor contributions (<1% to 12%) to total sediment CaCO3, and the main parts are attributed to terrigenous CaCO3 debris and relict shell fragments.

  6. Osteological development of wild-captured larvae and a juvenile Sebastes koreanus (Pisces, Scorpaenoidei from the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Hyo Jae Yu

    2016-06-01

    Full Text Available Abstract The osteological development in Sebastes koreanus is described and illustrated on the basis of 32 larvae [6.11–11.10 mm body length (BL] and a single juvenile (18.60 mm BL collected from the Yellow Sea. The first-ossified skeletal elements, which are related to feeding, swimming, and respiration, appear in larvae of 6.27 mm BL; these include the jaw bones, palatine, opercular, hyoid arch, and pectoral girdle. All skeletal elements are fully ossified in the juvenile observed in the study. Ossification of the neurocranium started in the frontal, pterotic, and parietal regions at 6.27 mm BL, and then in the parasphenoid and basioccipital regions at 8.17 mm BL. The vertebrae had started to ossify at ~7.17 mm BL, and their ossification was nearly complete at 11.10 mm BL. In the juvenile, although ossification of the pectoral girdle was fully complete, the fusion of the scapula and uppermost radial had not yet occurred. Thus, the scapula and uppermost radial fuse during or after the juvenile stage. The five hypurals in the caudal skeleton were also fused to form three hypural elements. The osteological results are discussed from a functional viewpoint and in terms of the comparative osteological development in related species.

  7. Reprint of Mechanisms of maintaining high suspended sediment concentration over tide-dominated offshore shoals in the southern Yellow Sea

    Science.gov (United States)

    Xiong, Jilian; Wang, Xiao Hua; Wang, Ya Ping; Chen, Jingdong; Shi, Benwei; Gao, Jianhua; Yang, Yang; Yu, Qian; Li, Mingliang; Yang, Lei; Gong, Xulong

    2018-06-01

    An understanding of the dynamics and behaviors of suspended sediments is vital in analysis of morphological, environmental, and ecological processes occurring in coastal marine environments. To study the mechanisms of maintaining high suspended sediment concentrations (SSCs) on a tide-dominated offshore shoal, we measured water depths, current velocities, SSCs, wave parameters and bottom sediment compositions in the southern Yellow Sea. These data were then used to calculate bottom shear stresses generated by currents (τc), waves (τw), and wave-current interactions (τcw). SSCs time series exhibited strong quarter-diurnal peaks during spring tides, in contrast to the semidiurnal signal during neap tides. A Fourier analysis showed that suspended sediment variations within tidal cycles was mainly controlled by resuspension in most stations. There existed relatively stable background SSCs (maintaining high SSCs among tidal cycles) values at all four stations during both windy (wind speed > 9.0 m/s) and normal weather conditions (wind speed value of 0.21 N/m2. On account of the strong tidal currents, background SSCs of spring tides were greater than that of neap tides. In addition, on the base of wavelet, statistics analyses and turbulence dissipation parameter, background SSCs during slack tide in the study area may be maintained by intermittent turbulence events induced by a combined tidal current and wave action.

  8. Environmental occurrence and distribution of organic UV stabilizers and UV filters in the sediment of Chinese Bohai and Yellow Seas.

    Science.gov (United States)

    Apel, Christina; Tang, Jianhui; Ebinghaus, Ralf

    2018-04-01

    Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Atmospheric input of trace substances into the North Sea and the Baltic Sea. Stoffeintrag in Nord- und Ostsee ueber die Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, H; Eppel, D; Petersen, G; Schneider, B; Weber, H; Gandrass, J; Reinhardt, K H; Wodarg, D; Fliess, J

    1989-01-01

    The concentrations and deposition of atmospheric trace substances were measured over the Kiel Bight and the Southern North Sea. A European longrange-transport model was used to calculate the atmospheric concentrations of trace metals and their deposition into the North Sea and the Baltic Sea. Natural and anthropogenic emitted element concentrations could be separated definitely by the measurements, and preferred transport directions of anthropogenic contributions could be found. Concentrations measured over the North Sea could be related to the surrounding emission areas by airmass trajectory analyses. The deposition measurements show that the main removal process is due to deposition by precipitation. Calculated and measured concentrations at several receptor points agreed well. The model results confirm the dominating role of wet deposition. It could be shown that extrapolations from measurements at coastal stations to the whole sea area tend to overestimate the total deposition into North Sea and Baltic Sea. (orig.) With 78 refs., 26 tabs., 85 figs.

  10. Surfactant control of air-sea gas exchange from North Sea coastal waters and the Atlantic Meridional Transect

    Science.gov (United States)

    Pereira, R.

    2016-02-01

    Suppression of gas transfer velocity (kw) by surfactants are well established, both in laboratory wind flumes and purposeful oceanic releases. However, the effects on kw of time and space varying concentrations of natural surfactant are inadequately studied. We have developed an automated gas exchange tank for simultaneous high precision measurement of kw in unmodified seawater samples. Here we present data from two studies along a coastal North Sea transect during 2012-2013 and the Atlantic Meridional Transect (AMT) 24 from September to November 2014. Measurements of surfactant activity (SA), CDOM absorbance and chlorophyll-a have enabled us to characterize the effects of variable amounts of natural surfactant on kw. North Sea coastal waters range in k660 (kw normalized to the value for CO2 in freshwater at 20oC) was 6.8-24.5 cm hr-1 (n=20), with the ranges of SA, total CDOM absorbance (200-450 nm) and chlorophyll-a measured in the surface microlayer (SML) of our seawater samples were 0.08-0.38 mg l-1 T-X-100, 0.13-4.7 and 0.09-1.54 µg l-1, respectively. The AMT k660 ranged from 7.0-23.9 cm hr-1 (n=22), with SA measured in the SML and subsurface water (SSW) of our seawater samples ranging from 0.15-1.08 mg l-1 T-X-100 and 0.07-0.43 mg l-1 T-X-100, respectively. Importantly, we found 12-45% (North Sea) and 1-43% (AMT) k660 suppression relative to Milli-Q water that relate to seasonal and spatial differences in SA. The North Sea demonstrated notable seasonal influences on k660 suppression that were related to CDOM absorbance and chlorophyll-a. The degree of k660 suppression was highest in summer consistent with k660 control by natural surfactant. The degree of k660 suppression decreased with distance offshore in the North Sea and displayed a strong relationship with SA (r2 = 0.51-0.64, p = 0.02, n = 20). The AMT demonstrated notable differences in k660 suppression between hemispheres and across the Longhurst Provinces but the overall relationship between k660

  11. Ulva and Enteromorpha (Ulvaceae, Chlorophyta) from two sides of the Yellow Sea: analysis of nuclear rDNA ITS and plastid rbcL sequence data

    Science.gov (United States)

    Wang, Jinfeng; Li, Nan; Jiang, Peng; Boo, Sung Min; Lee, Wook Jae; Cui, Yulin; Lin, Hanzhi; Zhao, Jin; Liu, Zhengyi; Qin, Song

    2010-07-01

    Ulvacean green seaweeds are common worldwide; they formed massive green tides in the Yellow Sea in recent years, which caused marine ecological problems as well as a social issue. We investigated two major genera of the Ulvaceae, Ulva and Enteromorpha, and collected the plastid rbcL and nuclear ITS sequences of specimens of the genera in two sides of the Yellow Sea and analyzed them. Phylogenetic trees of rbcL data show the occurrence of five species of Enteromorpha ( E. compressa, E. flexuosa, E. intestinalis, E. linza and E. prolifera) and three species of Ulva ( U. pertusa, U. rigida and U. ohnoi). However, we found U. ohnoi, which is known as a subtropical to tropical species, at two sites on Jeju Island, Korea. Four ribotypes in partial sequences of 5.8S rDNA and ITS2 from E. compressa were also found. Ribotype network analysis revealed that the common ribotype, occurring in China, Korea and Europe, is connected with ribotypes from Europe and China/Japan. Although samples of the same species were collected from both sides of the Yellow Sea, intraspecific genetic polymorphism of each species was low among samples collected worldwide.

  12. A decision support system for assessing offshore wind energy potential in the North Sea

    International Nuclear Information System (INIS)

    Schillings, Christoph; Wanderer, Thomas; Cameron, Lachlan; Tjalling van der Wal, Jan; Jacquemin, Jerome; Veum, Karina

    2012-01-01

    Offshore wind energy (OWE) in the North Sea has the potential to meet large share of Europe’s future electricity demand. To deploy offshore wind parks in a rational way, the overall OWE potential has to be realistically determined. This has to be done on an international, cross-border level and by taking into account the existing man-made and nature-related uses of the North Sea. As spatial conflicts will arise between existing uses and the new OWE uses, a Decision Support System (DSS) based on a Geographic Information System (GIS) was developed. Based on data of existing sea uses and calculation rules for spatial prioritisation analysis, the DSS helps in identifying areas that are (1) generally suitable for offshore wind power, (2) strictly excluded or (3) negotiable with respect to other existing sea uses. The combination of this conflict analysis together with cost assumptions for offshore wind farms and their expected electricity yield leads to identification of favourable areas for OWE deployment in the North Sea. This approach helps to reduce the conflict between offshore wind deployment and existing sea uses in the North Sea for future planning. The results can assist decision makers in developing transnational roadmaps for OWE. - Highlights: ► Decision Support System (DSS) to identify offshore wind energy (OWE) potential in the North Sea. ► Spatial analysis of existing sea use functions and offshore wind energy potential. ► Input parameters of DSS depend on the level of OWE spatial priority assumed by the user. ► DSS performs the required calculations and provides results in form of maps and statistics. ► DSS available after registration at (www.windspeed.eu).

  13. Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; TeSlaa, Joshua L.; Jónsson, Jón Eínar; Ballard, Jennifer R.; Harms, Naomi Jane; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology. PMID:26677841

  14. Avian influenza ecology in North Atlantic sea ducks: Not all ducks are created equal

    Science.gov (United States)

    Hall, Jeffrey S.; Russell, Robin E.; Franson, J. Christian; Soos, Catherine; Dusek, Robert J.; Allen, R. Bradford; Nashold, Sean W.; Teslaa, Joshua L.; Jónsson, Jón Einar; Ballard, Jennifer R.; Harms, Naomi Jnae; Brown, Justin D.

    2015-01-01

    Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

  15. Radiocaesium (137Cs) in marine mammals from Svalbard, the Barents Sea and the North Greenland Sea

    International Nuclear Information System (INIS)

    Andersen, Magnus; Gwynn, Justin P.; Dowdall, Mark; Kovacs, Kit M.; Lydersen, Christian

    2006-01-01

    Specific activities of the anthropogenic radionuclide, 137 Cs, were determined in marine mammals from Svalbard and the Barents and North Greenland Seas. Muscle samples were collected from 12 polar bears, 15 ringed seals, 10 hooded seals, 7 bearded seals, 14 harp seals, one walrus, one white whale and one blue whale in the period 2000-2003. The mean concentrations (± SD) of 137 Cs were: 0.72 ± 0.62 Bq/kg wet weight (w.w.) for polar bears; 0.49 ± 0.07 Bq/kg w.w. for ringed seals; 0.25 ± 0.10 Bq/kg w.w. for hooded seals; 0.22 ± 0.11 Bq/kg w.w. for bearded seals; 0.36 ± 0.13 Bq/kg w.w. for harp seals; 0.67 Bq/kg w.w. for the white whale sample; 0.24 Bq/kg w.w. for the blue whale; and below detection limit for the walrus. Significant differences in 137 Cs specific activities between some of the species were found. Ringed seals had higher specific activities than the other seal species in the study. Bearded seals and hooded seals had similar values, which were both significantly lower than the harp seal values. The results in the present study are consistent with previous reported results, indicating low specific activities of 137 Cs in Arctic marine mammals in the Barents Sea and Greenland Sea region during the last 20 years. The species specific differences found may be explained by varying diet or movement and distribution patterns between species. No age related patterns were found in specific activities for the two species (polar bears and hooded seals) for which sufficient data was available. Concentration factors (CF) of 137 Cs from seawater were determined for polar bears, ringed, bearded, harp and hooded seals. Mean CF values ranged from 79 ± 32 (SD) for bearded seals sampled in 2002 to 244 ± 36 (SD) for ringed seals sampled in 2003 these CF values are higher than those reported for fish and benthic organisms in the literature, suggesting bioaccumulation of 137 Cs in the marine ecosystem

  16. The acclimative biogeochemical model of the southern North Sea

    Science.gov (United States)

    Kerimoglu, Onur; Hofmeister, Richard; Maerz, Joeran; Riethmüller, Rolf; Wirtz, Kai W.

    2017-10-01

    Ecosystem models often rely on heuristic descriptions of autotrophic growth that fail to reproduce various stationary and dynamic states of phytoplankton cellular composition observed in laboratory experiments. Here, we present the integration of an advanced phytoplankton growth model within a coupled three-dimensional physical-biogeochemical model and the application of the model system to the southern North Sea (SNS) defined on a relatively high resolution (˜ 1.5-4.5 km) curvilinear grid. The autotrophic growth model, recently introduced by Wirtz and Kerimoglu (2016), is based on a set of novel concepts for the allocation of internal resources and operation of cellular metabolism. The coupled model system consists of the General Estuarine Transport Model (GETM) as the hydrodynamical driver, a lower-trophic-level model and a simple sediment diagenesis model. We force the model system with realistic atmospheric and riverine fluxes, background turbidity caused by suspended particulate matter (SPM) and open ocean boundary conditions. For a simulation for the period 2000-2010, we show that the model system satisfactorily reproduces the physical and biogeochemical states of the system within the German Bight characterized by steep salinity; nutrient and chlorophyll (Chl) gradients, as inferred from comparisons against observation data from long-term monitoring stations; sparse in situ measurements; continuous transects; and satellites. The model also displays skill in capturing the formation of thin chlorophyll layers at the pycnocline, which is frequently observed within the stratified regions during summer. A sensitivity analysis reveals that the vertical distributions of phytoplankton concentrations estimated by the model can be qualitatively sensitive to the description of the light climate and dependence of sinking rates on the internal nutrient reserves. A non-acclimative (fixed-physiology) version of the model predicted entirely different vertical profiles

  17. Eddy Mediated Nutrient Pattern in the North Eastern Arabian Sea

    Science.gov (United States)

    Thachaparambil, M.; Moolakkal Antony, R.; B R, S.; V N, S.; N, C.; M, S.

    2016-02-01

    A Cold Core Eddy (CCE) mediated nutrient pattern in the North Eastern Arabian Sea (NEAS) is explained based on in situ measurments during March 2013 onboard FORV Sagar Sampada which was not reported earlier in the area. Samples for physical, chemical and biological parameters were collected in 5 stations along the diameter of the eddy and following standard protocols. The core of the CCE is identified at 21°20.38'N; 66°30.68'E with a diameter of 120Km. Earlier studies explaining the process and the forcing mechanism of the particular eddy records that, the eddy is short term (1-3 months) and is regular during the season. Surface waters were well oxygenated (>4.8 ml L-1) in the core. Surface value of nutrients viz., Nitrate, Nitrite, Silicate and phosphate in the core regions was 0.9µM, 0.01 µM, 0.5 µM and 0.7 µM respectively indicating upwelling in the core. Spring intermonsoon (SIM) is generally termed as a transition period between the active winter and summer seasons and as per earlier studies, high biological production and the regularly occurring Noctilica bloom is supported by the nutrient loading due to convective mixing during winter as well as regenerated production. However, present observations shows that, nutrient pumping due to the upwelling associated with the CCE also contributes for sustaining high biological production and are evident in the Chl a and mesozooplankton biovolume which records values of 4.35mg/m3 and 1.09ml/m3 respectively in the core. An intense Noctiluca blooms observed in the western flank of the eddy (Chl a 13.25 mg/m3; cell density 5.8×106 cells/litre), where Nitrate concentration records 1.04µM explains the role of such mesoscale processes in the sustenance of the HAB events. While eastern flank of the CCE showed typical open ocean condition of the season showing Nitrate 0.08µM; Chl a 0.23mg/m3; and phytoplankton cell density as 421 cells/litre. Keywords: Cold core eddy, nutrients, NEAS, SIM, biological production

  18. Observed sea-level rise in the north Indian Ocean coasts during the past century

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    Content-Type text/plain; charset=UTF-8 91 Observed sea-level rise in the north Indian Ocean coasts during the past century A. S. Unnikrishnan National Institute of Oceanography, Dona Paula, Goa-403004 unni@nio.org Introduction Sea-level... rise is one of the good indicators of global warming. Rise in sea level occurs mainly through melting of glaciers, thermal expansion due to ocean warming and some other processes of relatively smaller magnitudes. Sea level rise is a global...

  19. Deglacial and Holocene sea-ice variability north of Iceland and response to ocean circulation changes

    Science.gov (United States)

    Xiao, Xiaotong; Zhao, Meixun; Knudsen, Karen Luise; Sha, Longbin; Eiríksson, Jón; Gudmundsdóttir, Esther; Jiang, Hui; Guo, Zhigang

    2017-08-01

    Sea-ice conditions on the North Icelandic shelf constitute a key component for the study of the climatic gradients between the Arctic and the North Atlantic Oceans at the Polar Front between the cold East Icelandic Current delivering Polar surface water and the relatively warm Irminger Current derived from the North Atlantic Current. The variability of sea ice contributes to heat reduction (albedo) and gas exchange between the ocean and the atmosphere, and further affects the deep-water formation. However, lack of long-term and high-resolution sea-ice records in the region hinders the understanding of palaeoceanographic change mechanisms during the last glacial-interglacial cycle. Here, we present a sea-ice record back to 15 ka (cal. ka BP) based on the sea-ice biomarker IP25, phytoplankton biomarker brassicasterol and terrestrial biomarker long-chain n-alkanols in piston core MD99-2272 from the North Icelandic shelf. During the Bølling/Allerød (14.7-12.9 ka), the North Icelandic shelf was characterized by extensive spring sea-ice cover linked to reduced flow of warm Atlantic Water and dominant Polar water influence, as well as strong meltwater input in the area. This pattern showed an anti-phase relationship with the ice-free/less ice conditions in marginal areas of the eastern Nordic Seas, where the Atlantic Water inflow was strong, and contributed to an enhanced deep-water formation. Prolonged sea-ice cover with occasional occurrence of seasonal sea ice prevailed during the Younger Dryas (12.9-11.7 ka) interrupted by a brief interval of enhanced Irminger Current and deposition of the Vedde Ash, as opposed to abruptly increased sea-ice conditions in the eastern Nordic Seas. The seasonal sea ice decreased gradually from the Younger Dryas to the onset of the Holocene corresponding to increasing insolation. Ice-free conditions and sea surface warming were observed for the Early Holocene, followed by expansion of sea ice during the Mid-Holocene.

  20. 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.

  1. Flux, Budget and Sources of Black Carbon (BC) in the Continental Shelf of the Bohai and Yellow Seas, China

    Science.gov (United States)

    Fang, Y.; Chen, Y.; Tian, C.

    2015-12-01

    Black carbon (BC) derived from incomplete combustion of fossil fuels and biomass has received increasing attention due to their potential importance in a wide range of biogeochemical processes. China has been generally considered as the world's largest BC emitter. Due to a combination of the prevailing East Asia monsoon and large amounts of riverine outflow, BC released from China can be transported to the adjacent continental shelf seas, the Bohai Sea (BS) and Yellow Sea (YS). Based on measurements of BC in 191 surface sediments, 36 riverine water, and 2 seawater samples, as well as the reported BC data set of the aerosol samples in the Bohai Rim, the concentration, flux, and budget of BC in the BS and YS were investigated. The spatial distribution of the BC concentration in surface sediments was largely influenced by the regional hydrodynamic conditions, with high values mainly occurring in the central mud areas. The BC burial flux in the BS and YS ranged from 4 to 1100 μg/cm2/yr, and averaged 166 ± 200 μg/cm2/yr. The area-integrated sedimentary BC sink flux in the entire BS and YS was ~325 Gg/yr. The BC budget calculated in the BS showed that atmospheric deposition and riverine discharge played comparable importance in delivering BC to the BS, and sequestration to bottom sediments was the major BC output pattern, accounting for ~88% of the total input BC. Besides, we attempted to apportion the BC sources in the BS and YS surface sediments using PAHs (organic molecular proxies cogenerated with BC) and BC as an input data to the Positive Matrix Factorization (PMF) receptor model. Results showed that ~83% of the sediment BC was attributed to the combustion of fossil fuels, and the remaining ~17% was from biomass burning. Due to the differences in their production mechanisms and therefore physicochemical properties, the above distinction and quantification would help us better understand their different environmental behaviors in the complex continental shelf

  2. Storing CO{sub 2} under the North Sea Basin - A key solution for combating climate change

    Energy Technology Data Exchange (ETDEWEB)

    Skogen, T; Morris, B; Agerup, M; Svenningsen, S Oe; Kropelien, K F; Solheim, M; Northmore, B; Dixon, T; O' Carroll, K; Greaves, A; Golder, J; Selmer-Olsen, S; Sjoeveit, A; Kaarstad, O; Riley, N; Wright, I; Mansfield, C

    2007-06-15

    This report represents the first deliverable of the North Sea Basin Task Force, which Norway and the UK established in November 2005 to work together on issues surrounding the transport and storage of CO{sub 2} beneath the North Sea. The North Sea represents the best geological opportunity for storing our CO{sub 2} emissions away from the atmosphere for both the UK and Norway

  3. Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice.

    Science.gov (United States)

    Li, Xichen; Holland, David M; Gerber, Edwin P; Yoo, Changhyun

    2014-01-23

    In recent decades, Antarctica has experienced pronounced climate changes. The Antarctic Peninsula exhibited the strongest warming of any region on the planet, causing rapid changes in land ice. Additionally, in contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not declined, but has instead undergone a perplexing redistribution. Antarctic climate is influenced by, among other factors, changes in radiative forcing and remote Pacific climate variability, but none explains the observed Antarctic Peninsula warming or the sea-ice redistribution in austral winter. However, in the north and tropical Atlantic Ocean, the Atlantic Multidecadal Oscillation (a leading mode of sea surface temperature variability) has been overlooked in this context. Here we show that sea surface warming related to the Atlantic Multidecadal Oscillation reduces the surface pressure in the Amundsen Sea and contributes to the observed dipole-like sea-ice redistribution between the Ross and Amundsen-Bellingshausen-Weddell seas and to the Antarctic Peninsula warming. Support for these findings comes from analysis of observational and reanalysis data, and independently from both comprehensive and idealized atmospheric model simulations. We suggest that the north and tropical Atlantic is important for projections of future climate change in Antarctica, and has the potential to affect the global thermohaline circulation and sea-level change.

  4. Sea surface temperature and sea ice variability in the subpolar North Atlantic from explosive volcanism of the late thirteenth century

    DEFF Research Database (Denmark)

    Sicre, M. -A.; Khodri, M.; Mignot, J.

    2013-01-01

    In this study, we use IP25 and alkenone biomarker proxies to document the subdecadal variations of sea ice and sea surface temperature in the subpolar North Atlantic induced by the decadally paced explosive tropical volcanic eruptions of the second half of the thirteenth century. The short-and long......-term evolutions of both variables were investigated by cross analysis with a simulation of the IPSL-CM5A LR model. Our results show short-term ocean cooling and sea ice expansion in response to each volcanic eruption. They also highlight that the long response time of the ocean leads to cumulative surface cooling...... and subsurface heat buildup due to sea ice capping. As volcanic forcing relaxes, the surface ocean rapidly warms, likely amplified by subsurface heat, and remains almost ice free for several decades....

  5. The radon-222 transfer coefficients across air-sea interface determined in the Bering Sea, the Okhotsk Sea and the North Pacific Ocean

    International Nuclear Information System (INIS)

    Kholujskij, S.N.; Anikiev, V.V.; Popov, N.I.

    1995-01-01

    Determination of velocity coefficient for gas flow transfer across the natural sea surface into the atmosphere (K v ) was attempted by means of radon method on board the SRS Academician Alexander Nesmeyanov (July-August 1992). The measurements were conducted in the Bering Sea, the Okhotsk Sea and in the North Pacific Ocean. It is shown that the total range of the K v observed values equaled from 1.8 up to 5.4 m.day, which is within the known limits for other regions of the world ocean. 9 refs., 1 fig

  6. Seismic stratigraphy of the Heuksan mud belt in the southeastern Yellow Sea, Korea

    Science.gov (United States)

    Lee, Gwang-Soo; Yoo, Dong Geun; Bae, Sung Ho; Min, Gun-Hong; Kim, Seong-Pil; Choi, Hunsoo

    2015-12-01

    To establish the seismic stratigraphy of the Heuksan mud belt (HMB) and reconstruct its depositional history, approximately 1,600 km of high-resolution seismic data were newly obtained using chirp acoustic sub-bottom profiler, sparker, and air-gun seismic systems. Based on seismic stratigraphic analysis, the HMB can be divided into three major seismic units (I, II, and III, from top to bottom) and four subunits (II-a, II-b, III-a, and III-b) overlying transgressive sands, pre-last glacial maximum (LGM) deposits, and the acoustic basement. Each unit and subunit show different seismic facies and geometry, being clearly separated from each other by bounding surfaces formed since the LGM. The spatial distribution, thicknesses and volumes of the seismic units were determined and plotted to document the sequential formation of the HMB. The correlation between deep drill core data (HMB-101, HMB-102, HMB-103, YSDP-101, and YSDP-102) and the seismic data suggests that subunits III-b and III-a were formed by the continuous accumulation of fine-grained sediment with partial sandy sediment in an estuarine/deltaic environment during the early to middle transgressive stage, accompanied by landward migration of the shoreline. Subunits II-b and II-a were probably formed by re-deposition of large volumes of sediment eroded from unit III during the middle transgressive to early highstand stage. Unit I is interpreted as the most recent mud deposit representing the highstand systems tract when sea-level rise terminated. The careful definition of seismic units and their interpretation proposed in this study, on the basis of the large and partly new seismic dataset covering the entire HMB together with deep drill core data, have been instrumental in reconstructing the depositional environment and formation mechanisms of the HMB.

  7. Observations on the anterior testicular ducts in snakes with emphasis on sea snakes and ultrastructure in the yellow-bellied sea snake, Pelamis platurus.

    Science.gov (United States)

    Sever, David M; Freeborn, Layla R

    2012-03-01

    The anterior testicular ducts of squamates transport sperm from the seminiferous tubules to the ductus deferens. These ducts consist of the rete testis, ductuli efferentes, and ductus epididymis. Many histological and a few ultrastructural studies of the squamate reproductive tract exist, but none concern the Hydrophiidae, the sea snakes and sea kraits. In this study, we describe the anterior testicular ducts of six species of hydrophiid snakes as well as representatives from the Elapidae, Homolapsidae, Leptotyphlopidae, and Uropeltidae. In addition, we examine the ultrastructure of these ducts in the yellow-bellied Sea Snake, Pelamis platurus, only the third such study on snakes. The anterior testicular ducts are similar in histology in all species examined. The rete testis is simple squamous or cuboidal epithelium and transports sperm from the seminiferous tubules to the ductuli efferentes in the extratesticular epididymal sheath. The ductuli efferentes are branched, convoluted tubules composed of simple cuboidal, ciliated epithelium, and many species possess periodic acid-Schiff+ granules in the cytoplasm. The ductus epididymis at the light microscopy level appears composed of pseudostratified columnar epithelium. At the ultrastructural level, the rete testis and ductuli efferentes of P. platurus possess numerous small coated vesicles and lack secretory vacuoles. Apocrine blebs in the ductuli efferentes, however, indicate secretory activity, possibly by a constitutive pathway. Ultrastructure reveals three types of cells in the ductus epididymis of P. platurus: columnar principal cells, squamous basal cells, and mitochondria-rich apical cells. This is the first report of apical cells in a snake. In addition, occasional principal cells possess a single cilium, which has not been reported in reptiles previously but is known in some birds. Finally, the ductus epididymis of P. platurus differs from other snakes that have been studied in possession of apical, biphasic

  8. Recruitment in a changing environment: the 2000s North Sea herring recruitment failure

    DEFF Research Database (Denmark)

    Payne, Mark; Hatfield, E.M.C.; Dickey-Collas, M.

    2009-01-01

    Environmentally induced change appears to be impacting the recruitment of North Sea herring (Clupea harengus). Despite simultaneously having a large adult population, historically low exploitation, and Marine Stewardship Council accreditation (implying sustainability), there have been an unpreced......Environmentally induced change appears to be impacting the recruitment of North Sea herring (Clupea harengus). Despite simultaneously having a large adult population, historically low exploitation, and Marine Stewardship Council accreditation (implying sustainability), there have been...... an unprecedented 6 sequential years of poor juvenile production (recruitment). Analysis suggests that the poor recruitment arises during the larval overwintering phase, with recent survival rates greatly reduced. Contemporary warming of the North Sea has caused significant changes in the plankton community...

  9. Grey gurnard ( Eutrigla gurnadus ) in the North Sea: an emerging key predator?

    DEFF Research Database (Denmark)

    Floeter, J.; Kempf, A.; Vinther, Morten

    2005-01-01

    Grey gurnard (Eutrigla gurnadus) is a widely distributed demersal species in the North Sea that has been ranked frequently among the 10 dominant species. Since the late 1980s, grey gurnard catch rates in the international bottom trawl surveys showed a pronounced increase and it was included...... as an "other predator" in the North Sea multispecies virtual population analysis (MSVPA) in 1997. The MSVPA results estimated grey gurnard to be responsible for approximately 60% of the total predation mortality on age-0 Atlantic cod (Gadus morhua). Long-term MSVPA predictions led to the extinction of North...... Sea cod. As a possible technical reason, the Holling type II functional response implemented in the model was discussed. In the current analysis, it was demonstrated that the Holling type II functional response was not responsible for the extinction of cod in the model, which was rather a true effect...

  10. The contribution of ship emissions to air pollution in the North Sea regions

    Energy Technology Data Exchange (ETDEWEB)

    Matthias, Volker, E-mail: volker.matthias@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Bewersdorff, Ines [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Aulinger, Armin, E-mail: armin.aulinger@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Quante, Markus, E-mail: markus.quante@gkss.d [GKSS Research Centre Geesthacht, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany)

    2010-06-15

    As a consequence of the global distribution of manufacturing sites and the increasing international division of labour, ship traffic is steadily increasing and is becoming more and more important as an origin of air pollution. This study investigates the impact of ship emissions in coastal areas of the North Sea under conditions of the year 2000 by means of a regional chemistry transport model which runs on a sufficiently high resolution to study air pollution in coastal regions. It was found that northern Germany and Denmark in summer suffer from more than 50% higher sulphate, nitrate and ammonium aerosol concentrations due to contributions from ships. The implementation of a sulphur emission control area (SECA) in the North Sea, as it was implemented at the end of 2007, directly results in reduced sulphur dioxide and sulphate aerosol concentrations while nitrate aerosol concentrations are slightly increased. - Ship emissions lead to significantly enhanced air pollution by secondary inorganic aerosols in North Sea coastal areas.

  11. Quantifying pelagic-benthic coupling in the North Sea: Are we asking the right question?

    DEFF Research Database (Denmark)

    Richardson, K.; Cedhagen, T.

    2002-01-01

    is devoted to obtaining more and better data describing this exchange. Efforts to quantify exchange between the water column and the sediment must continue. However, such studies will not, in themselves, lead to a quantification of pelagic-benthic coupling in the North Sea. We identify here other areas......The coupling between pelagic and benthic processes occurs through the signals sent between the water column and the seabed. Huge methodological challenges are associated with the quantification of the signals being sent between these two domains - especially in a relatively shallow and heavily...... fished region such as the North Sea where deployment of sediment traps or bottom mounted cameras or samplers is difficult. Thus, there are relatively few sites in the North Sea for which good data are available for describing pelagic-benthic (or near shore-offsbore) coupling and considerable effort...

  12. Estimation of new production in the North Sea: consequences for temporal and spatial variability of phytoplankton

    DEFF Research Database (Denmark)

    Richardson, Katherine; Bo Pedersen, Flemming

    1998-01-01

    By coupling knowledge of oceanographic processes and phytoplankton responses to light and nutrient availability, we estimate a total potential new (sensu Dugdale and Goering,1967) production for the North Sea of approximately 15.6 million tons C per year. In a typical year, about 40......% of this production will be associated with the spring bloom in the surface waters of the seasonally stratified (central and northern) North Sea. About 40% is predicted to occur in the coastal waters while the remaining new production is predicted to take place in sub-surface chlorophyll peaks occuring in association...... with fronts in the North Sea during summer month. By considering the inter-annual variation in heat, wind and nutrient availability (light and tidal energy input are treated as non-varying from year to year), the inter-annual variability in the new production occuring in these different regions is estimated...

  13. Critical report of current fisheries management measures implemented for the North Sea mixed demersal fisheries

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Ulrich, Clara; Hegland, Troels J.

    the scientific advice, the development in recent years has been towards this gap being reduced. Management of the fisheries has undergone a number of structural and behavioral changes, and these have already yielded some positive results as the state of the demersal stocks in the North Sea have globally improved......, at least in the prosperous countries around the North Sea, provides only few jobs. Despite the above trends indicating positive effects of the most recent fisheries management of the North Sea mixed demersal fisheries there are a row of general problems in the present management. Population dynamics...... states’ ministers in the Council have exercised strong control over the fisheries management measures which have been developed and adopted on the background of proposals from the Commission and the Parliament, though since the ratification of the Lisbon Treaty the Parliament has assumed a role of co...

  14. Water scaling in the North Sea oil and gas fields and scale prediction: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, M

    1997-12-31

    Water-scaling is a common and major production chemistry problem in the North Sea oil and gas fields and scale prediction has been an important means to assess the potential and extent of scale deposition. This paper presents an overview of sulphate and carbonate scaling problems in the North Sea and a review of several widely used and commercially available scale prediction software. In the paper, the water chemistries and scale types and severities are discussed relative of the geographical distribution of the fields in the North Sea. The theories behind scale prediction are then briefly described. Five scale or geochemical models are presented and various definitions of saturation index are compared and correlated. Views are the expressed on how to predict scale precipitation under some extreme conditions such as that encountered in HPHT reservoirs. 15 refs., 7 figs., 9 tabs.

  15. Comparative study of air quality by the North Sea and Baltic Sea; Vergleichsuntersuchungen der Luftqualitaet an Nord- und Ostsee

    Energy Technology Data Exchange (ETDEWEB)

    Moriske, H.J.; Turowski, E.; Klar, A.; Schoendube, M.; Ebert, G.; Konieczny, L. [Umweltbundesamt, Berlin (Germany). Inst. fuer Wasser-, Boden- und Lufthygiene

    2000-01-01

    Air quality measurements were carried out in the North Sea and Baltic Sea regions. The results are summarized in this contribution from the hygienic view. [German] Im Rahmen eines Forschungsprojektes des Umweltbundesamtes, das zwischen 1996 und 1998 mit dem Titel 'Erfassung gasfoermiger und partikelfoermiger Bestandteile der Umgebungsluft an Nord- und Ostsee - Untersuchungen zur hygienischen Bedeutung des maritimen Aerosols' durchgefuehrt wurde, sollte die Frage unterschiedlicher Luftqualitaet an Nord- und Ostsee beantwortet werden und eine aktuelle Bestandsaufnahme vorgenommen werden. Der Artikel fasst die Forschungsergebnisse aus hygienischer Sicht zusammen. (orig./SR)

  16. Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)

    DEFF Research Database (Denmark)

    Pham, M.K.; Sanchez-Cabeza, J.A.; Povinec, P.P.

    2006-01-01

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (K-40, Cs-137, Th-232, U-234, U-235, U-238, Pu-238, Pu239+240 and Am-241) were...... ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units. (c) 2006 Elsevier Ltd. All...

  17. The introduction of radionuclides over the atmosphere into the North Sea

    International Nuclear Information System (INIS)

    Kautsky, H.

    1983-01-01

    Although it is barely possible to provide exact data concerning the aerosol entry and the quantities of precipitation in the region of the North Sea, an attempt will be made to estimate the annual entry of radionuclides in the North Sea. As data for the calculations, available estimations of the quantity of precipitation over the sea, the content of radionuclides in the air and in the rain over land and the activities conveyed thereby to the earth, as well as the emission quantities of radionuclides with the exhaust air from nuclear power plants, are applied. It is quite clear that Tritium represents by far the main part of the radionuclides which enter the sea via precipitation. The majority of the other artificial radio nuclides, on the other hand, are to be viewed as being quantitatively insignificant. (orig./HP) [de

  18. Glaciotectonic deformations in the Jammerbugt and glaciodynamic development in the eastern North Sea

    DEFF Research Database (Denmark)

    Pedersen, Stig A. Schack; Boldreel, Lars Ole

    2017-01-01

    –Early Weichselian Skærumhede Group, indicating a Saalian age of the glaciotectonic deformation. The balancing of the thrust fault structures shows that the thrust sheets in the tailing end of the complex had their source in the Skagerrak sea. The hole caused by displacement contributed to formation of the Skagerrak......The Quaternary geology in the eastern part of the North Sea is characterized by large-scale glaciotectonic complexes. The northernmost complex is the Jammerbugt Glaciotectonic Complex here addressed, which occupies an area of more than 300km2. It was recently recognized during an investigation...... of conventional seismic profiles located about 10km offshore the west coast of northern Denmark. The deformed bedrock includes the main part of the Cretaceous Chalk Group in the North Sea. In the northern part of the complex the detachment surface is situated in Lower Cretaceous greensand about 400m below sea...

  19. Historical marine ecology: examining the role of fisheries in changes in North Sea benthos.

    Science.gov (United States)

    Robinson, Leonie A; Frid, Chris L J

    2008-07-01

    The organisms living on and in the sea floor, the benthos, represent an important ecological group. Although some (shellfish) have an economic value, most do not, and so little long-term data are available. We have identified three sources of historic benthic data for the North Sea, a regional sea that has been subjected to multiple human impacts for at least several hundred years. Each dataset has its limitations, but by their use together some issues emerge. Wider community shifts were observed in the shorter term and a number of extirpations at the scale of the North Sea were seen over longer time scales. The extirpated taxa share a number of characteristics consistent with an effect of fisheries such as fragile morphology. We must concentrate now on furthering our understanding of the ecological significance of shifts in dominance of particular functional units and protecting those habitats and species most vulnerable to fisheries-driven extirpation.

  20. Formation and preservation of greigite (Fe3S4) in a thick sediment layer from the central South Yellow Sea

    Science.gov (United States)

    Liu, Jianxing; Mei, Xi; Shi, Xuefa; Liu, Qingsong; Liu, Yanguang; Ge, Shulan

    2018-04-01

    Sediments from continental shelves are sensitive to changes in both oceanic and terrestrial conditions, and, therefore, magnetic minerals in such sediments are affected strongly by depositional and diagenetic processes. Here, we investigated systematically an N-S transect of three sediment cores from the central South Yellow Sea (SYS) muddy area. Magnetic data indicate the presence of a horizontally distributed thick greigite-bearing layer. From an age model based on published magnetostratigraphy, accelerator mass spectrometry 14C dating ages, sedimentary characteristics and foraminiferal analysis, this layer was deposited within marine isotope stages (MIS) 17-13, following an enhanced sulphidic period over MIS 21-19 when the YS Warm Current and the associated YS Cold Water Mass were strong and where underlying sediments have higher total organic carbon, total sulphur and trace element molybdenum contents. Trace element cadmium enrichment in the greigite-bearing layers is documented for the first time, which indicates that weakly sulphidic (i.e. with trace levels of free H2S) conditions existed before greigite formed in a sulphidic environment during early diagenesis. It also indicates that subsequent conditions free of oxygen and H2S after greigite formation are more favourable for its preservation. We propose that organic matter supply was controlled over an extended period by moderate primary productivity. The combined effects of palaeoclimate and local tectonic subsidence were crucial for the formation and preservation of the identified greigite. In brief, our study improves understanding of the formation and preservation mechanisms of greigite in continental shelf sediments and reveals mid-Pleistocene palaeoenvironmental changes in the SYS.

  1. Microplastics in a wind farm area: A case study at the Rudong Offshore Wind Farm, Yellow Sea, China.

    Science.gov (United States)

    Wang, Teng; Zou, Xinqing; Li, Baojie; Yao, Yulong; Li, Jiasheng; Hui, Hejiu; Yu, Wenwen; Wang, Chenglong

    2018-03-01

    Despite the rapid construction of offshore wind farms, the available information regarding the risks of this type of development in terms of emerging pollutants, particularly microplastics, is scarce. In this study, we quantified the level of microplastic pollution at an offshore wind farm in the Yellow Sea, China, in 2016. The abundance of microplastics was 0.330 ± 0.278 items/m 3 in the surface water and 2.58 ± 1.14 items/g (dry) in the sediment. To the best of our knowledge, the level of microplastic pollution in our study area was slightly higher than that in coastal areas around the world. The microplastics detected in the surface waters and sediments were mainly fibrous (75.3% and 68.7%, respectively) and consisted of some granules and films. The microplastics in the samples might originate from garments or ropes via wastewater discharge. The abundance of plastic in the water and sediment samples collected from the wind farm area was lower than that in the samples collected from outside the wind farm area. The anthropogenic hydrodynamic effect was the main factor affecting the local distribution of microplastics. The presence of a wind farm could increase the bed shear stress during ebb tide, disturbing the bed sediment, facilitating its initiation and transport, and ultimately increasing the ease of washing away the microplastics adhered to the sediment. This study will serve as a reference for further studies of the distribution and migration of microplastics in coastal zones subjected to similar marine utilization. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Culture and hybridization experiments on an ulva clade including the Qingdao strain blooming in the yellow sea.

    Directory of Open Access Journals (Sweden)

    Masanori Hiraoka

    2011-05-01

    Full Text Available In the summer of 2008, immediately prior to the Beijing Olympics, a massive green tide of the genus Ulva covered the Qingdao coast of the Yellow Sea in China. Based on molecular analyses using the nuclear encoded rDNA internal transcribed spacer (ITS region, the Qingdao strains dominating the green tide were reported to be included in a single phylogenetic clade, currently regarded as a single species. On the other hand, our detailed phylogenetic analyses of the clade, using a higher resolution DNA marker, suggested that two genetically separate entities could be included within the clade. However, speciation within the Ulva clade has not yet been examined. We examined the occurrence of an intricate speciation within the clade, including the Qingdao strains, via combined studies of culture, hybridization and phylogenetic analysis. The two entities separated by our phylogenetic analyses of the clade were simply distinguished as U. linza and U. prolifera morphologically by the absence or presence of branches in cultured thalli. The inclusion of sexual strains and several asexual strains were found in each taxon. Hybridizations among the sexual strains also supported the separation by a partial gamete incompatibility. The sexually reproducing Qingdao strains crossed with U. prolifera without any reproductive boundary, but a complete reproductive isolation to U. linza occurred by gamete incompatibility. The results demonstrate that the U. prolifera group includes two types of sexual strains distinguishable by crossing affinity to U. linza. Species identification within the Ulva clade requires high resolution DNA markers and/or hybridization experiments and is not possible by reliance on the ITS markers alone.

  3. Heavy metals in intensive greenhouse vegetable production systems along Yellow Sea of China: Levels, transfer and health risk.

    Science.gov (United States)

    Hu, Wenyou; Huang, Biao; Tian, Kang; Holm, Peter E; Zhang, Yanxia

    2017-01-01

    Recently, greenhouse vegetable production (GVP) has grown rapidly and counts a large proportion of vegetable production in China. In this study, the accumulation, health risk and threshold values of selected heavy metals were evaluated systematically. A total of 120 paired soil and vegetable samples were collected from three typical intensive GVP systems along the Yellow Sea of China. Mean concentrations of Cd, As, Hg, Pb, Cu and Zn in greenhouse soils were 0.21, 7.12, 0.05, 19.81, 24.95 and 94.11 mg kg -1 , respectively. Compared to rootstalk and fruit vegetables, leafy vegetables had relatively high concentrations and transfer factors of heavy metals. The accumulation of heavy metals in soils was affected by soil pH and soil organic matter. The calculated hazard quotients (HQ) of the heavy metals by vegetable consumption decreased in the order of leafy > rootstalk > fruit vegetables with hazard index (HI) values of 0.61, 0.33 and 0.26, respectively. The HI values were all below 1, which indicates that there is a low risk of greenhouse vegetable consumption. Soil threshold values (STVs) of heavy metals in GVP system were established according to the health risk assessment. The relatively lower transfer factors of rootstalk and fruit vegetables and higher STVs suggest that these types of vegetables are more suitable for cultivation in greenhouse soils. This study will provide an useful reference for controlling heavy metals and developing sustainable GVP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Tracing perfluoroalkyl substances (PFASs) in soils along the urbanizing coastal area of Bohai and Yellow Seas, China.

    Science.gov (United States)

    Meng, Jing; Wang, Tieyu; Song, Shuai; Wang, Pei; Li, Qifeng; Zhou, Yunqiao; Lu, Yonglong

    2018-07-01

    With the shift of fluorine chemical industry from developed countries to China and increasing demand for fluorine chemical products, occurrence of perfluoroalkyl substances (PFASs) in production and application areas has attracted more attention. In this study, 153 soil samples were collected from 21 cities along the urbanizing coastal area of the Bohai and Yellow Seas. PFASs in this area were relatively higher, compared with other study areas. The concentrations ranged from 2.76 to 64.0 ng g -1 , and those in most sites were between 2.76 and 13.9 ng g -1 , with a predominance of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Among the 21 coastal cities, contaminations of PFASs in Zibo, Nantong and Binzhou were elevated, which was likely affected by local fluorine chemical plants, equipment manufacturing and chemical industry, respectively. The total emissions of PFOA and PFOS were similar, with amount of 4431 kg and 4335 kg, respectively. Atmospheric deposition was the largest source, accounting for 93.2% of total PFOA and 69.6% of PFOS, respectively. In addition, due to application of aqueous film-forming foams (AFFFs) and sulfluramid, disposal of sewage sludge and stacking of solid waste, emission of PFOA and PFOS to soil was 1617 kg, accounting for 9.29% of the whole China. In general, pollution in Jiangsu, Shandong and Tianjin was more serious than those in Liaoning and Hebei, which was consistent with industrialization level and size of industrial sectors emitting PFASs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Culture and Hybridization Experiments on an Ulva Clade Including the Qingdao Strain Blooming in the Yellow Sea

    Science.gov (United States)

    Hiraoka, Masanori; Ichihara, Kensuke; Zhu, Wenrong; Ma, Jiahai; Shimada, Satoshi

    2011-01-01

    In the summer of 2008, immediately prior to the Beijing Olympics, a massive green tide of the genus Ulva covered the Qingdao coast of the Yellow Sea in China. Based on molecular analyses using the nuclear encoded rDNA internal transcribed spacer (ITS) region, the Qingdao strains dominating the green tide were reported to be included in a single phylogenetic clade, currently regarded as a single species. On the other hand, our detailed phylogenetic analyses of the clade, using a higher resolution DNA marker, suggested that two genetically separate entities could be included within the clade. However, speciation within the Ulva clade has not yet been examined. We examined the occurrence of an intricate speciation within the clade, including the Qingdao strains, via combined studies of culture, hybridization and phylogenetic analysis. The two entities separated by our phylogenetic analyses of the clade were simply distinguished as U. linza and U. prolifera morphologically by the absence or presence of branches in cultured thalli. The inclusion of sexual strains and several asexual strains were found in each taxon. Hybridizations among the sexual strains also supported the separation by a partial gamete incompatibility. The sexually reproducing Qingdao strains crossed with U. prolifera without any reproductive boundary, but a complete reproductive isolation to U. linza occurred by gamete incompatibility. The results demonstrate that the U. prolifera group includes two types of sexual strains distinguishable by crossing affinity to U. linza. Species identification within the Ulva clade requires high resolution DNA markers and/or hybridization experiments and is not possible by reliance on the ITS markers alone. PMID:21573216

  6. Interannual sedimentary effluxes of alkalinity in the southern North Sea: Model results compared with summer observations

    OpenAIRE

    Pätsch, Johannes; Kühn, Wilfried; Six, Katharina D.

    2018-01-01

    For the sediments of the central and southern North Sea different sources of alkalinity generation are quantified by a regional modelling system for the period 2000–2014. For this purpose a formerly global ocean sediment model coupled with a pelagic ecosystem model is adopted to shelf sea dynamics where much larger turnover rates than in the open and deep ocean occurs. To track alkalinity changes due to different nitrogen-related processes the open ocean sediment model was extended by t...

  7. EDXRS study of aerosol composition variations in air masses crossing the North Sea

    International Nuclear Information System (INIS)

    Injuk, J.; Malderen, H. van; Grieken, R. van; Swietlicki, E.; Knox, J.M.; Schofield, R.

    1993-01-01

    X-ray emission techniques for bulk and individual particle analysis (EDXRF, EPXMA, micro-PIXE) were combined and applied in atmospheric research on the North Sea area as part of a field-study on air-sea exchange processes of particulate matter. The atmospheric loading for a number of elements was determined by EDXRF, yielding bulk concentrations for Mg, Al, Si, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br and Sr. From these EDXRF data, deposition rates were derived and, based on a classical multivariate statistical approach, different aerosol sources were identified. Complementary to this work, EPXMA combined with automated image analysis was applied to individual size-segregated aerosol particles to determine their inorganic composition, physical size and shape. Also, the first results of micro-PIXE analyses on individual North Sea aerosol particles, particularly their large-size fraction, are discussed and compared with the corresponding EPXMA results. In summary, such a joint approach with the use of different x-ray emission techniques contributed to the resolution of the mixed structure of the lower North Sea troposphere and to the determination of the atmospheric supply of material to the North Sea environment. (author)

  8. Two centuries of observed atmospheric variability and change over the North Sea region

    Science.gov (United States)

    Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard; Woollings, Tim

    2016-04-01

    In the upcoming North Sea Region Climate Change Assessment (NOSCCA), we present a synthesis of current knowledge about past, present and possible future climate change in the North Sea region. A climate change assessment from published scientific work has been conducted as a kind of regional IPCC report, and a book has been produced that will be published by Springer in 2016. In the framework of the NOSCCA project, we examine past and present studies of variability and changes in atmospheric variables within the North Sea region over the instrumental period, roughly the past 200 years, based on observations and reanalyses. The variables addressed in this presentation are large-scale circulation, pressure and wind, surface air temperature, precipitation and radiative properties (clouds, solar radiation, and sunshine duration). While air temperature over land, not unexpectedly, has increased everywhere in the North Sea region, with strongest trends in spring and in the north of the region, a precipitation increase has been observed in the north and a decrease in the south of the region. This pattern goes along with a north-eastward shift of storm tracks and is in agreement with climate model projections under enhanced greenhouse gas concentrations. For other variables, it is not obvious which part of the observed changes may be due to anthropogenic activities and which is internally forced. It remains also unclear to what extent atmospheric circulation over the North Sea region is influenced by distant factors, in particular Arctic sea-ice decline in recent decades. There are indications of an increase in the number of deep cyclones (but not in the total number of cyclones), while storminess since the late 19th century shows no robust trends. The persistence of circulation types appears to have increased over the last century, and consequently, there is an indication for 'more extreme' extreme events. However, changes in extreme weather events are difficult to assess

  9. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  10. Combining sea state and land subsidence rates in an assessment of flooding hazards at the Danish North Sea coast

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Broge, Niels; Knudsen, Per

    Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series fr...... the coast are presented and the town of Thyboron is used as a case where, in addition to SLR and extremes, analyses of land movement and ocean-groundwater interactions are included in an integrated method for assessing future coastal flooding hazards.......Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series from...

  11. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    OpenAIRE

    Morato, T.; Kvile, K. Ø.; Taranto, G. H.; Tempera, F.; Narayanaswamy, B. E.; Hebbeln, D.; Menezes, G. M.; Wienberg, C.; Santos, R. S.; Pitcher, T. J.

    2013-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic) and in the Medite...

  12. Seamount physiography and biology in North-East Atlantic and Mediterranean Sea

    OpenAIRE

    T. Morato; K. Ø. Kvile; G. H. Taranto; F. Tempera; B. E. Narayanaswamy; D. Hebbeln; G. Menezes; C. Wienberg; R. S. Santos; T. J. Pitcher

    2012-01-01

    This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (North-East Atlantic Ocean) and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in-situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (North-East Atlantic) and in Mediterran...

  13. Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

    Science.gov (United States)

    Xiao, Ziniu; Li, Delin

    2016-06-01

    The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

  14. Remarks on the sea level records of the north Indian ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    variability in the tide gauge records along the coasts of the north Indian Ocean A. S. Unnikrishnan National Institute of Oceanography, Dona Paula, Goa, India 403004 e-mail: unni@nio.org Introduction Global sea-level rise has been relatively well... studied by making use of the coastal tide gauge data that are available (Woodworth and Player, 2003) through the Permanent Service for Mean Sea Level (PSMSL). However, studies on regional sea level rise have not gathered momentum, similar to those on a...

  15. Variability and Dynamics of Dissolved Oxygen in the Transition Zone of the North Sea and the Baltic Sea

    DEFF Research Database (Denmark)

    Jonasson, Lars

    information about the seasonal to decadal oxygen variations in the bottom water of the Kattegat, the Danish Straits, the Sound and the Western Baltic Sea and investigates the relative importance of physical and biogeochemical processes, climate change and nutrient load reductions on the oxygen variability......The bottom water in the transition zone of the North Sea and Baltic Sea suffers from seasonal hypoxia, usually during late summer and autumn. Hypoxia is a natural phenomenon in this region because of the strong vertical stratification which prevents the bottom water to be ventilated by atmospheric...... concentrations by 15-30 μmol O2 l−1 yr−1 while the reduced nutrient concentration has increased the oxygen concentration with approximately the same amount. Thus, the positive effect on oxygen conditions from reduced nutrient concentrations have been counteracted by increased water temperatures. This has made...

  16. Effort allocation of the Dutch beam trawl fleet in response to a temporarily closed area in the North Sea

    NARCIS (Netherlands)

    Rijnsdorp, A.D.; Piet, G.J.; Poos, J.J.

    2001-01-01

    The spawning stock of North Sea cod is at a historic low level and immediate management measures are needed to improve this situation. As a first step, the European Commission in 2001 closed a large area in the North Sea between February 15 and April 30 to all cod related fishing fleets in order to

  17. The occurrence of the Flying Fish, Hirundichthys speculiger (Valenciennes, 1847), in the North Sea (Pisces, Atheriniformes, Exocoetidae)

    NARCIS (Netherlands)

    Boer, P.; Nijssen, H.

    1972-01-01

    The occurrence of a specimen of the Flying Fish Hirundichthys speculiger (Valenciennes, 1847) in the North Sea is recorded. This is the first record of a member of the family Exocoetidae in the coastal waters of the Netherlands. The specimen is illustrated, and its occurrence in the North Sea is

  18. North Sea Scyphomedusae; summer distribution, estimated biomass and significance particularly for 0-group Gadoid fish

    Science.gov (United States)

    Hay, S. J.; Hislop, J. R. G.; Shanks, A. M.

    Data on the by-catch of Scyphomedusae from pelagic trawls was collected during the routine ICES International 0-group Gadoid Surveys of the North Sea, in June and July of the years 1971-1986 (except 1984). These data are used to describe the distributions, abundances and biomasses of three common North Sea Scyphomedusae: Aurelia aurita (L.), Cyanea capillata (L.) and C. lamarckii (Péron & Lesuer). Information is also presented on inter-annual variability, size (umbrella diameter) frequencies and, for the Cyanea species, umbrella diameter: wet weight relationships. The general role and ecological significance of Scyphomedusae is discussed and, given the well known 'shelter' relationships between Scyphomedusae and certain 0-group fish, whiting ( Merlangius merlangus) and haddock ( Melanogrammus aeglefinus), in particular. The data were examined for evidence of such relationships. Aurelia aurita, although fairly widespread in the northern North Sea was virtually absent from the central North Sea but very abundant in coastal waters. This species was particularly abundant off the Scottish east coast and especially in the Moray Firth. Cyanea lamerckii was most abundant in the southern and eastern North Sea. More widespread than Aurelia, this species was also most abundant in coastal regions, particularly off the Danish west coast. Cyanea capillata, with a more northern distribution was also more widely distributed and abundant offshore. This species was most abundant in the area between the Orkney/Shetland Isles and the Norwegian Deep and in shelf waters of the north west approaches to the North Sea. As with C. lamarckii it was also, in some years, abundant off the Scottish east coast and west of Denmark. The abundance and the size frequency of the jellyfish show considerable inter-annual variability, and variability between regions of the North Sea. It is considered that hydrographic variability and differences in food supply to both medusae and to their sessile

  19. Fission track analysis and evolution of mesozoic-paleozoic hydrocarbon resource-rocks headed in Northern Jiangsu-South Yellow sea basin

    International Nuclear Information System (INIS)

    Xu Hong; Cai Qianzhong; Sun Heqing; Guo Zhenxuan; Yan Guijing; Dai Jing; Liu Dongying

    2008-01-01

    Fission track data of different geologic epoches from Binhai salient, Yancheng sag, Haian sag, Baiju sag, Gaoyou sag, Hongze sag and Jinhu sag of northern Jiangsu basin and seismic data from Laoshan uplift in South Yellow Sea basin and evolution of Paleozoic hydrocarbon resource-rocks headed in the Northern Jiangsu-South Yellow Sea basin were studied. Results indicate that Binhai salient uplifted in 38-15 Ma, forming 'structure uplifting model', Paleozoic hydrocarbon resource-rocks have the appearance of 'different layers but identical mature, different layers but identical temperature' with Laoshan uplift. All sags have the characters of 'long time heating model', and sedimentations in Cenozoic were exploited by 2 km. Mesozoic-Paleozoic hydrocarbon resource- rocks of Laoshan uplift get ahead of 10 km. Structure evolution was compared with Binhai salient. According to the modeling results of secondary hydrocarbon generation, Mesozoic-Paleozoic hydrocarbon resource-rocks of Laoshan uplift have the good reservoir potentiality and probably become an important new window for sea oil and gas exploration. (authors)

  20. A review on the Holocene evolution of an inner-shelf mud deposit in the southeastern Yellow Sea: the Huksan Mud Belt

    Science.gov (United States)

    Lee, Hee Jun

    2015-12-01

    The Huksan Mud Belt (HMB) has been extensively investigated with respect to its source and evolution since the 1980s. Studies on sediment budget or accumulation rates suggested two different origins, Korean and combined Korean and Chinese. However, neither of the suggested origins appears reliable because they were based on insufficient or inaccurate datasets on the basic sedimentological characteristics of the HMB. Although a major mud transport was inferred to be closely associated with either the Korean Coastal Current or the Yellow Sea Warm Current, their physical characters during the Holocene transgression have been rarely hind-casted thus far. The majority of studies on high-resolution seismic stratigraphy along with core log have suggested that the HMB stratigraphy consists of two units divided by an erosional boundary. The lower unit is further divided into two subunits by a subtle discontinuity that is laterally correlated with the erosional boundary. In line with the stratigraphy, the studies theorized that the erosion of the HMB had produced a re-deposited distal lobe, the younger lower subunit. In addition, this lobe was inferred to have prograded rapidly during the relatively short period of 6,500-5,500 yr B.P. Although the time interval of the erosion coincides with the decelerating rise in sea level, the hydrodynamic cause and effect of the erosion remain inexplicable. Therefore, the source and evolution of the HMB continue to be controversial, due largely to poor understanding of the paleo-physical oceanography of the Yellow Sea during the Holocene.

  1. Across the North Sea : The impact of the Dutch Republic

    NARCIS (Netherlands)

    Lottum, J.-J. van

    2007-01-01

    For a long time the early modern population of North Western Europe has been looked upon as fairly sedentary. Although since the 1980s new research has shown that people were much more mobile than was earlier acknowledged, in many historical works either the industrial revolution or the Napoleonic

  2. Morphology and controlling mechanisms of shallow water pockmarks in the Yellow Sea Basin of China: employing multibeam bathymetry, backscatter data and subbottom profile

    Science.gov (United States)

    Liu, X.

    2017-12-01

    The presence of fluid escape features like seafloor pockmarks are observed in continental margin basins and ocean floors worldwide. While most of the reported depressions developed at deep water, this study provides a description of shallow pockmark field in shallow water that no deep than 55m in continent of the Yellow Sea. Combined with the multi-beam bathymetry data, terrain slope and the back- scattering intensity data, this study calculated the morphological parameters of the seabed pockmarks and carried out quantitative analysis. The outline of the seabed pockmarks were accurately defined, and 282 pockmarks with circle, elliptic, or elongated shape in the plan view were analyzed in ArcGIS. The average diameter of the pockmarks was 0.94 km, average area and circumference were 0.88 km2 and 3.82 km, the pockmarks also have the aspect ratio of 1.83, and relief from 0.5m to 2.5 m. The profile of the pockmarks shaped like W1, W2 and V, respectively distributed in the north, south, and west of the pockmark group. The large plane size but small vertical scale may be associated with the low concentration of the fluid. The orientation of the major axis of the pockmarks has 3 major directions, pockmarks aligned around ENE - WSW, NNE SSW consistent with the main direction of the bottom current in the study area, while pockmarks aligned around NNW-SSE direction mainly controlled by submarine topography. Some pockmark clustered as pockmark chain, which shows that the pockmark shape controlled by the ancient river or lagoon of the sedimentary strata. The acoustic backscatter strength of the pockmark area is of -71dB to -60dB, the average strength data inside the pockmark is significantly higher than the outside, with a difference of 5dB. The high backscatter strength may attribute to the coarse sediments that left inside the pockmark due to winnowing of fine-grained sediments, or result of the precipitation of diagenitic or authigenic minerals associated with fluid venting.

  3. Are white-beaked dolphins Lagenorhynchus albirostris food specialst? Their diet in the southern North Sea

    NARCIS (Netherlands)

    Jansen, O.E.; Leopold, M.F.; Meesters, H.W.G.; Smeenk, C.

    2010-01-01

    The white-beaked dolphin Lagenorhynchus albirostris is the most numerous cetacean after the harbour porpoise Phocoena phocoena in the North Sea, including Dutch coastal waters. In this study, the diet of 45 white-beaked dolphins stranded on the Dutch coast between 1968 and 2005 was determined by

  4. Aerosol properties over the Arabian Sea during the north east monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Dulac, F; Leon, G.F; Desa, E.

    440, 670, 870, 936, 940 and 1020 mm, in the Arabian Sea between 15.4-17.86 degrees N and 73.28-69.3 degrees E, during the North East monsoon period of 1-10 December, 1998. The aerosol optical properties derived from these data showed variations from...

  5. Changes in pollution load and environmental trends in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Pawlak, Janet

    1998-12-01

    This publication relates to the quality of the marine environment in the North Sea. Changes in pollution load and environmental trends are analysed. Main themes discussed cover chemical contaminants, temporal trends contaminants in biota, inputs of contaminants to the marine environment, and biological effects of contaminants and biological monitoring. 14 refs., 5 figs., 4 tabs.

  6. Towards harmonised assessment and classification of "biodiversity status" in the North Sea eco-region

    DEFF Research Database (Denmark)

    Skov, H.; Andersen, Jesper; Vinther, M.

    As one of the milestones in the HARMONY-project a demonstration of the application of the integrative indicator based biodiversity assessment tool (BEAT) was undertaken for the Greater North Sea sub-region across a range of coastal and offshore areas. The first version of the BEAT tool was applie...

  7. The south-eastern North Sea : losses of vertebrate fauna during the past 2000 years

    NARCIS (Netherlands)

    Wolff, W.J.

    At least 31 species of marine mammals, marine and coastal birds, and marine and anadromous fish have disappeared temporarily or permanently from the coasts of The Netherlands and in most cases also from the south-eastern North Sea (south of 54 degrees N) during the past 2000 years-In 18-22 cases,

  8. Thermoluminescence dating of abyssal deposits in the north region of the South China Sea

    International Nuclear Information System (INIS)

    Peng Xiaoxian

    1988-01-01

    The ages of abyssal deposits have been studied by TL dating. The ages of the deposits from the wells Weima 1, 5 and 6 at the slope in the north of the South China Sea are 36,100 and 128 thousand years respectively

  9. Trophic impact of Atlantic bluefin tuna migrations in the North Sea

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Andersen, Ken Haste; Lindegren, Martin

    2017-01-01

    and the stability of the fish community. The impact of a migrating top-predator is investigated here for Atlantic bluefin tuna in the North Sea. Bluefin tuna has been absent from the region for half-century, but recent years have seen recovery of migrations and a return of bluefin tuna in the area. We use a size...

  10. Simulated wind-generated inertial oscillations compared to current measurements in the northern North Sea

    Science.gov (United States)

    Bruserud, Kjersti; Haver, Sverre; Myrhaug, Dag

    2018-04-01

    Measured current speed data show that episodes of wind-generated inertial oscillations dominate the current conditions in parts of the northern North Sea. In order to acquire current data of sufficient duration for robust estimation of joint metocean design conditions, such as wind, waves, and currents, a simple model for episodes of wind-generated inertial oscillations is adapted for the northern North Sea. The model is validated with and compared against measured current data at one location in the northern North Sea and found to reproduce the measured maximum current speed in each episode with considerable accuracy. The comparison is further improved when a small general background current is added to the simulated maximum current speeds. Extreme values of measured and simulated current speed are estimated and found to compare well. To assess the robustness of the model and the sensitivity of current conditions from location to location, the validated model is applied at three other locations in the northern North Sea. In general, the simulated maximum current speeds are smaller than the measured, suggesting that wind-generated inertial oscillations are not as prominent at these locations and that other current conditions may be governing. Further analysis of the simulated current speed and joint distribution of wind, waves, and currents for design of offshore structures will be presented in a separate paper.

  11. Amino acids and hexosamines as indicators of organic matter degradation state in North Sea sediments

    NARCIS (Netherlands)

    Dauwe, B.; Middelburg, J.J.

    1998-01-01

    Sediment cores from six stations in the eastern North Sea were analyzed for protein amino acids, the nonprotein amino acids beta-alanine and gamma-aminobutyric acid and the hexosamines galactosamine and glucosamine, and bulk parameters (organic carbon, nitrogen, total hydrolyzable amino acids and

  12. Differential growth of larval sprat Sprattus sprattus across a tidal front in the eastern North Sea

    DEFF Research Database (Denmark)

    Munk, Peter

    1993-01-01

    Spatial variations in abundance and growth of larval sprat Sprattus sprattus L. were examined across a tidal front in the eastern North Sea, off the west coast of Denmark. The aim of the study was to evaluate the potential advantage for sprat larvae of residing in the vicinity of a tidal front...

  13. PHYTOPLANKTON OF THE NORTH-SEA AND ITS DYNAMICS - A REVIEW

    NARCIS (Netherlands)

    REID, PC; LANCELOT, C; GIESKES, WWC; HAGMEIER, E; WEICHART, G

    1990-01-01

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m-2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of

  14. Changes in the North Sea fish community: evidence of indirect effects of fishing?

    NARCIS (Netherlands)

    Daan, N.; Gislason, H.; Pope, J.G.; Rice, J.C.

    2005-01-01

    We investigate changes in the North Sea fish community with particular reference to possible indirect effects of fishing, mediated through the ecosystem. In the past, long-term changes in the slope of size spectra of research vessel catches have been related to changes in fishing effort, but such

  15. Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

    NARCIS (Netherlands)

    Franeker, van J.A.; Blaize, C.; Danielsen, J.

    2011-01-01

    The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of

  16. Comparison between predicted and observed sand waves and sand banks in the North Sea

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; van den Brink, G.M.

    2001-01-01

    For the first time a prediction model of regular morphological patterns on the seabed was tested against observations of sand wave and sand bank occurrence in the entire North Sea. The model, which originates from first physical principles, predicts this occurrence via two dimensionless parameters

  17. Seamount physiography and biology in the north-east Atlantic and Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    T. Morato

    2013-05-01

    Full Text Available This work aims at characterising the seamount physiography and biology in the OSPAR Convention limits (north-east Atlantic Ocean and Mediterranean Sea. We first inferred potential abundance, location and morphological characteristics of seamounts, and secondly, summarized the existing biological, geological and oceanographic in situ research, identifying examples of well-studied seamounts. Our study showed that the seamount population in the OSPAR area (north-east Atlantic and in the Mediterranean Sea is large with around 557 and 101 seamount-like features, respectively. Similarly, seamounts occupy large areas of about 616 000 km2 in the OSPAR region and of about 89 500 km2 in the Mediterranean Sea. The presence of seamounts in the north-east Atlantic has been known since the late 19th century, but overall knowledge regarding seamount ecology and geology is still relatively poor. Only 37 seamounts in the OSPAR area (3.5% of all seamounts in the region, 22 in the Mediterranean Sea (9.2% of all seamounts in the region and 25 in the north-east Atlantic south of the OSPAR area have in situ information. Seamounts mapped in both areas are in general very heterogeneous, showing diverse geophysical characteristics. These differences will likely affect the biological diversity and production of resident and associated organisms.

  18. EPXMA survey of shelf sediments (Southern Bight, North Sea): A glance beyond the XRD-invisible

    NARCIS (Netherlands)

    De Maeyer-Worobiec, A.; Dekov, V.M.; Laane, R.W.P.M.; van Grieken, R.

    2009-01-01

    Shelf sediments of the southern North Sea, were studied with a microanalytical [electron probe X-ray microanalysis (EPXMA)] and two bulk [X-ray diffraction (XRD) and X-ray fluorescence (XRF)] techniques. The investigation proved that the promptness of the microanalytical method is combined with a

  19. The environmental impact and recovery at two dumping sites for dredged material in the North Sea

    NARCIS (Netherlands)

    Stronkhorst, J.; Ariese, F.; Hattum, van B.; Postma, J.F.; Kluijver, de M.; Besten, den P.; Bergman, M.J.N.; Daan, R.; Murk, A.J.; Vethaak, A.D.

    2003-01-01

    The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity,

  20. PHYTOPLANKTON OF THE NORTH-SEA AND ITS DYNAMICS - A REVIEW

    NARCIS (Netherlands)

    REID, PC; LANCELOT, C; GIESKES, WWC; HAGMEIER, E; WEICHART, G

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m-2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of

  1. Fulmar Litter EcoQO monitoring along Durch and North Sea coasts

    NARCIS (Netherlands)

    Franeker, van J.A.

    2011-01-01

    Wastes from ships are an important source of litter in the marine environment in the Southern North Sea and cause serious economic and ecological damage. Inadequacies in the ship to shore waste delivery procedures are considered a major factor in illegal discharges. The European Union addressed the

  2. Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

    NARCIS (Netherlands)

    Van Engeland, T.; Soetaert, K.E.R.; Knuijt, A.; Laane, R.W.P.M.; Middelburg, J.J.

    2010-01-01

    Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the

  3. Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria

    NARCIS (Netherlands)

    Hermsen, E.; Pompe, R.; Besseling, E.; Koelmans, A.A.

    2017-01-01

    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of > 20 μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a

  4. Radiological implications from the temporal development of radioactivity in marine food from the North Sea

    International Nuclear Information System (INIS)

    Kanisch, G.; Nagel, G.; Krueger, A.; Kellermann, H.-J.

    2000-01-01

    A subject of the revision of authorised limits in 1994 for the discharge of liquid radioactive waste by the reprocessing plant Sellafield (UK) was an increase of these limits for certain radionuclides ( 3 H, 14 C, 60 Co, 99 Tc and 129 I). It is investigated now how the radioactivity in marine biota from the North Sea and subsequently the public radiation exposure of seafood consumers has developed in the years since 1994. This is based on a compartment model for dispersion in the North-East Atlantic. Discharges from the reprocessing plants Dounreay (UK) and La Hague (F) are included in the assessment. It is deduced that about 60% of 137 Cs in the North Sea originate presently in the remobilisation of old Sellafield discharges from the Irish Sea sediment. A comparison with measured biota data shows that the model is conservative in most cases. The public radiation exposure (artificial radionuclides) from ingestion of fish, crustaceans and molluscs from the central North Sea as the sum over 12 considered radionuclides has decreased from 1992 to 1998 from 0.13 to 0.08 μSv y -1 . (orig.)

  5. Modelling and analysis of offshore energy systems on North Sea oil and gas platforms

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Elmegaard, Brian; Pierobon, Leonardo

    2012-01-01

    export, and power generation. In this paper, a generic model of a North Sea oil and gas platform is described and the most thermodynamically inefficient processes are identified by performing an exergy analysis. Models and simulations are built and run with the tools Aspen Plus R, DNA and Aspen HYSYS R...

  6. Orbital calibration of the late Campanian carbon isotope event in the North Sea

    DEFF Research Database (Denmark)

    Perdiou, Anastasios; Thibault, Nicolas; Anderskouv, Kresten

    2016-01-01

    A new record of carbon isotopes, nannofossil biostratigraphy, gamma-ray and Fe content variations is presented for the upper Campanian of the Adda-3 core, Danish Central Graben, North Sea. The studied interval provides a revision of previously assigned late Coniacian to early Santonian ages. New...

  7. Temperature affects the timing of spawning and migration of North Sea mackerel

    DEFF Research Database (Denmark)

    Jansen, Teunis; Gislason, Henrik

    2011-01-01

    Climate change accentuates the need for knowing how temperature impacts the life history and productivity of economically and ecologically important species of fish. We examine the influence of temperature on the timing of the spawning and migrations of North Sea Mackerel using data from larvae C...

  8. Importance of ocean circulation in ecological modeling: An example from the North Sea

    Science.gov (United States)

    Skogen, Morten D.; Moll, Andreas

    2005-09-01

    There is an increasing number of ecological models for the North Sea around. Skogen and Moll (2000) [Skogen, M.D., Moll, A. 2000. Interannual variability of the North Sea primary production: comparison from two model studies. Continental Shelf Research 20 (2), 129-151] compared the interannual variability of the North Sea primary production using two state-of-the-art ecological models, NORWECOM and ECOHAM1. Their conclusion was that the two models agreed on an annual mean primary production, its variability and the timing and size of the peak production. On the other hand, there was a low (even negative dependent of area) correlation in the production in different years between the two models. In the present work, these conclusions are brought further. To try to better understand the observed differences between the two models, the two ecological models are run in an identical physical setting. With such a set-up also the interannual variability between the two models is in agreement, and it is concluded that the single most important factor for a reliable modeling of phytoplankton and nutrient distributions and transports within the North Sea is a proper physical model.

  9. Eleven bones: More fossil remains of Cave Lions and Cave Hyaenas from the North Sea area

    NARCIS (Netherlands)

    Bosscha Erdbrink, D.P.

    1983-01-01

    Six fossil Cave Lion bones and five fossil Cave Hyaena bones are described. One lion bone and one hyaena bone were dredged from the Westerschelde ( = Western Scheldt, southwestern part of the Netherlands). The other specimens were recovered from the bottom of the North Sea, in the area West and

  10. Description of the North Sea wind climate for wind energy applications

    NARCIS (Netherlands)

    Coelingh, J.P.; Wijk, A.J.M. van; Cleijne, J.W.; Pleune, R.

    1992-01-01

    In The Netherlands it is foreseen that wind turbines will be installed on offshore locations in the North Sea before the year 2010. Therefore adequate knowledge of the offshore wind climate should be obtained, both for the estimation of energy yields and for the determination of wind load

  11. Recent increase of North Sea houting and prospects for recolonization in the Netherlands

    NARCIS (Netherlands)

    Kranenbarg, J.; Winter, H.V.; Backx, J.J.G.M.

    2002-01-01

    Two monitoring programmes in estuarine and freshwater systems in the Netherlands both show a recent increase in anadromous North Sea houting Coregonus oxyrhynchus after it disappeared there in the 1940s. Most houting were immature and caught during the feeding season indicating that at present the

  12. Observations of copepod feeding and vertical distribution under natural turbulent conditions in the North Sea

    DEFF Research Database (Denmark)

    Visser, Andre; Saito, H.; Saiz, E.

    2001-01-01

    We present results of simultaneous measurements of turbulent- dissipation rate, zooplankton vertical distribution and copepod gut pigments in the northern North Sea. Analysis shows that some, but not all, copepods (by species, sex and stage) exhibit significant dependence on turbulence in respect...

  13. Dual hydraulic behaviour of the Chalk in the Netherlands North Sea

    NARCIS (Netherlands)

    Verweij, H.

    2006-01-01

    Information on the sedimentary development, seismic stratigraphy and burial compaction of the Chalk Group in the Netherlands North Sea was combined with pressure data and basin modelling to investigate the hydraulic behaviour of the Chalk Group in the Central Graben and Schill Grund High. The

  14. Mapping the spawning grounds of North Sea cod ( Gadus morhua ) by direct and indirect means

    DEFF Research Database (Denmark)

    Fox, C.J.; Taylor, M.; Dickey-Collas, M.

    2008-01-01

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey...

  15. Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means

    NARCIS (Netherlands)

    Fox, C.J.; Taylor, M.; Dickey-Collas, M.; Fossum, P.; Kraus, G.; Rohlf, N.; Damme, van C.J.G.; Bolle, L.J.

    2008-01-01

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey

  16. A lasting legacy for the Baltic and North Sea GLOBEC Germany program

    DEFF Research Database (Denmark)

    Peck, M.A.; Dutz, Jörg; Voss, R.

    2012-01-01

    This preface introduces four manuscripts that form a special theme section of the GLOBEC Germany program within Progress in Oceanography. The four manuscripts link changes in physical forcing to the trophodynamic structure and function of the Baltic and North Seas. The target species of GLOBEC Ge...... Germany included various species of calanoid copepods and a small pelagic fish (Sprattus sprattus)...

  17. Benthic nutrient cycling and diagenetic pathways in the North-western Black Sea

    NARCIS (Netherlands)

    Friedrich, J.; Dinkel, C.; Friedl, G.; Pimenov, N.; Wijsman, J.W.M.; Gomoiu, M-T.; Cociasu, A.; Popa, L.; Wehrli, B.

    2002-01-01

    Benthic fluxes of nutrients and metals were measured in the coastal zone of the north-western Black Sea, which is influenced by the Danube and Dniestr rivers. The results from the benthic flux chambers deployed during two EROS 21 cruises in summer 1995 and in spring 1997 yield information on benthic

  18. Covariance among North Sea nutrient and climate drivers: consequences for plankton dynamics.

    NARCIS (Netherlands)

    McQuatters-Gollop, A.; Vermaat, J.E.

    2011-01-01

    Regime shift and principal component analysis of a spatially disaggregated database capturing time-series of climatic, nutrient and plankton variables in the North Sea revealed considerable covariance between groups of ecosystem indicators. Plankton and climate time-series span the period 1958-2003,

  19. Temporal changes in plankton of the North Sea: community shfits and environmental drivers

    NARCIS (Netherlands)

    Alvarez-Fernandez, S.; Lindeboom, H.J.; Meesters, H.W.G.

    2012-01-01

    This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime

  20. Quantification of seep-related methane gas emissions at Tommeliten, North Sea

    NARCIS (Netherlands)

    Schneider von Deimling, J.S.; Rehder, G.; Greinert, J.; McGinnnis, D.F.; Boetius, A.; Linke, P.

    2011-01-01

    Tommeliten is a prominent methane seep area in the Central North Sea. Previous surveys revealed shallow gas-bearing sediments and methane gas ebullition into the water column. In this study, the in situ methane flux at Tommeliten is re-assessed and the potential methane transport to the atmosphere

  1. Density and viscosity behavior of a North Sea crude oil, natural gas liquid, and their mixtures

    DEFF Research Database (Denmark)

    Schmidt, KAG; Cisneros, Sergio; Kvamme, B

    2005-01-01

    to accurately model the saturation pressures, densities, and viscosities of petroleum systems ranging from natural gases to heavy crude oils. The applicability of this overall modeling technique to reproduce measured bubble points, densities, and viscosities of a North Sea crude oil, a natural gas liquid...

  2. Change of Static and Dynamic Elastic Properties due to CO² Injection in North Sea Chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, M.L.; Christensen, H.F.

    2012-01-01

    important in enhanced oil recovery by CO2 injection (CO2-EOR) in chalk as, chalk reservoirs are vulnerable to compaction under changed stress and pore fluid. From South Arne field, North Sea, we used Ekofisk Formation chalk having approximately 20% non-carbonate and Tor Formation chalk having less than 5...

  3. Effects of ocean acidification on primary production in a coastal North Sea phytoplankton community

    NARCIS (Netherlands)

    Eberlein, Tim; Wohlrab, Sylke; Rost, Björn; John, Uwe; Bach, Lennart T.; Riebesell, U.; Van de Waal, D.B.

    2017-01-01

    We studied the effect of ocean acidification (OA) on a coastal North Sea plankton community in a long-term mesocosm CO2-enrichment experiment (BIOACID II long-term mesocosm study). From March to July 2013, 10 mesocosms of 19 m length with a volume of 47.5 to 55.9 m3 were deployed in the Gullmar

  4. Lithostratigraphy of the Palaeogene - Lower Neogene succession of the Danish North Sea

    DEFF Research Database (Denmark)

    Schiøler, Poul-Henrik; Andsbjerg, Jan; Clausen, Ole Rønø

    2007-01-01

    sediments of the Danish sector of the North Sea is revised. The sediment package from the top of the Chalk Group to the base of the Nordland Group is subdivided into seven formations containing eleven new members. The existing Våle, Lista, Sele, Fur, Balder, Horda and Lark Formations of previously...

  5. Tracing estuarine organic matter sources into the southern North Sea using C and N isotopic signatures

    DEFF Research Database (Denmark)

    Bristow, Laura A.; Jickells, Timothy D.; Weston, Keith

    2013-01-01

    Sources and distribution of particulate organic matter in surface waters of the Humber and Thames estuaries and in the East Anglian plume in the southern North Sea were investigated in winter 2006/2007. Carbon (C) and nitrogen (N) stable isotopes provided evidence for the presence of three partic...

  6. Developments in the North Sea and their consequences for the marine environment

    NARCIS (Netherlands)

    Eisma, D.

    1981-01-01

    Summarizing, the marine environment of the North Sea is threatened in several ways: by waterpollution, by overfishing and by bottom disturbance. Fishing is now extremely regulated, but research on and control of stocks is only extended to commercial species. Strict regulations have been made for

  7. Do North Sea cod (Gadus morhua) fisheries maintain high catch rates at low stock size?

    DEFF Research Database (Denmark)

    Rindorf, Anna; Andersen, Bo Sølgaard

    2008-01-01

    This study presents all investigation of the relationship between stock size of North Sea cod (Gadus morhua) and catch rates in seven commercial fishing fleets. The shape of the relationship was estimated using a model allowing both density-dependent changes in catchability and bias...

  8. Critical report of current fisheries management measures implemented for the North Sea mixed demersal fisheries

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Ulrich, Clara; Hegland, Troels J.

    The present report is an EU-FP7-SOCIOEC Report giving an overview and critical evaluation of the current management measures implemented for the North Sea mixed demersal fisheries and the fish stocks involved in this. Also, this involves review and critical evaluation of the scientific advice...

  9. Development of north sea coastal plankton communities in separate plastic bags under identical conditions

    NARCIS (Netherlands)

    Kuiper, J.

    1977-01-01

    In two experiments lasting 4 to 6 weeks, communities of North Sea coastal plankton kept in separate plastic bags (of about 1400 l) and exposed to the same environmental conditions showed very similar patterns of growth and decline. This result means that the method is suitable for the evaluation of

  10. Floc size and aspects of flocculation processes of suspended particulate matter in the North Sea area

    NARCIS (Netherlands)

    Chen, S.

    1995-01-01

    Investigations on the size of suspended particulate matter in the North Sea and two adjacent estuaries were carried out using an in situ technique: image analysis of photographs from an underwater camera system. The results obtained from such an in situ method gave a new knowledge on the size

  11. Realized habitats of early-stage North Sea herring: looking for signals of environmental change

    DEFF Research Database (Denmark)

    Röckmann, C.; Dickey-Collas, M.; Payne, Mark

    2011-01-01

    Realized habitats of North Sea herring for two larval and two juvenile stages were estimated over the past 30 years, using abundances from surveys tied to modelled estimates of temperature and salinity. Newly hatched larvae (NHL) were found mainly in water masses of 9–11°C, pre-metamorphosis larvae...

  12. Gas deliveries from Haltenbanken/North Sea; Gassleveranser Haltenbanken/Nordsjoeen

    Energy Technology Data Exchange (ETDEWEB)

    Ramm, H.H.

    1995-12-31

    The conference paper relates to the development and delivery of natural gas from the Haltenbanken area and the North Sea on the Norwegian continental shelf. Alternatives of field developments and pipelines together with the allocation of contracts for securing the contractual delivery of natural gas to the European continent in future and an alternative delivery to the Scandinavian countries, are discussed. 2 figs.

  13. Shifts in North Sea forage fish productivity and potential fisheries yield

    NARCIS (Netherlands)

    Clausen, Lotte W.; Rindorf, Anna; Deurs, van Mikael; Dickey-Collas, Mark; Hintzen, Niels T.

    2018-01-01

    1. Forage fish populations support large scale fisheries and are key components of marine ecosystems across the world, linking secondary production to higher trophic levels. While climate-induced changes in the North Sea zooplankton community are described and documented in literature, the

  14. The paleocene in north Africa - Sea-level changes and paleoproductivity in Tunisa, Libya and Egypt using microfossils

    NARCIS (Netherlands)

    Guasti, E.; Lüning, S.

    2009-01-01

    The Paleocene is a time of warm oceans and generally high sea levels. In North Africa, vast epicontinental seas extended far inside the African continent. In this paper we correlate sea level, primary paleoproductivity and facies distribution of the proximal, carbonate-dominated Paleocene deposits

  15. Effects of air-sea coupling over the North Sea and the Baltic Sea on simulated summer precipitation over Central Europe

    Science.gov (United States)

    Ho-Hagemann, Ha Thi Minh; Gröger, Matthias; Rockel, Burkhardt; Zahn, Matthias; Geyer, Beate; Meier, H. E. Markus

    2017-12-01

    This study introduces a new approach to investigate the potential effects of air-sea coupling on simulated precipitation inland over Central Europe. We present an inter-comparison of two regional climate models (RCMs), namely, the COSMO-CLM (hereafter CCLM) and RCA4 models, which are configured for the EURO-CORDEX domain in the coupled and atmosphere-only modes. Two versions of the CCLM model, namely, 4.8 and 5.0, join the inter-comparison being almost two different models while providing pronouncedly different summer precipitation simulations because of many changes in the dynamics and physics of CCLM in version 5.0. The coupling effect on the prominent summer dry bias over Central Europe is analysed using seasonal (JJA) mean statistics for the 30-year period from 1979 to 2009, with a focus on extreme precipitation under specific weather regimes. The weather regimes are compared between the coupled and uncoupled simulations to better understand the mechanism of the coupling effects. The comparisons of the coupled systems with the atmosphere-only models show that coupling clearly reduces the dry bias over Central Europe for CCLM 4.8, which has a large dry summer bias, but not for CCLM 5.0 and RCA4, which have smaller dry biases. This result implies that if the atmosphere-only model already yields reasonable summer precipitation over Central Europe, not much room for improvement exists that can be caused by the air-sea coupling over the North Sea and the Baltic Sea. However, if the atmosphere-only model shows a pronounced summer dry bias because of a lack of moisture transport from the seas into the region, the considered coupling may create an improved simulation of summer precipitation over Central Europe, such as for CCLM 4.8. For the latter, the benefit of coupling varies over the considered timescales. The precipitation simulations that are generated by the coupled system COSTRICE 4.8 and the atmosphere-only CCLM 4.8 are mostly identical for the summer mean

  16. Occurrence of Ergasilus megaceros Wilson, 1916, in the sea lamprey and other fishes from North America

    Science.gov (United States)

    Muzzall, Patrick M.; Hudson, Patrick L.

    2004-01-01

    Ergasilus megaceros (Copepoda: Ergasilidae) was recovered from the nasal fossae (lamellae) of the olfactory sac in 1 (1.8%) of 56 sea lampreys, Petromyzon marinus Linne, 1758, collected in May 2002 from the Cheboygan River, Michigan. Although the sea lamprey is a new host record for E. megaceros, this fish species may not be a preferred host because of its low prevalence. Ergasilus megaceros is the second ergasilid species reported from the sea lamprey in North America. This is the third report of an ergasilid species infecting the nasal fossae of fishes in North America, with E. rhinos being the only other species reported from this site.

  17. Iron geochemistry and organic carbon preservation by iron (oxyhydr)oxides in surface sediments of the East China Sea and the south Yellow Sea

    Science.gov (United States)

    Ma, Wei-Wei; Zhu, Mao-Xu; Yang, Gui-Peng; Li, Tie

    2018-02-01

    In marine sediments factors that influence iron (Fe) geochemistry and its interactions with other elements are diverse and remain poorly understood. Here we comparatively study Fe speciation and reactive Fe-bound organic carbon (Fe-OC) in surface sediments of the East China Sea (ECS) and the south Yellow Sea (SYS). The objectives are to better understand the potential impacts of geochemically distinct sediment sources and depositional/diagenetic settings on Fe geochemistry and OC preservation by Fe (hydr)oxides in sediments of the two extensive shelf seas around the world. Contents of carbonate- and acid-volatile-sulfide (AVS)-associated Fe(II) (FeAVS + carb) and magnetite (Femag) in the ECS sediments are about 5 and 9 times higher, respectively, than in the SYS. This could be ascribed to the ferruginous conditions of the ECS sediments that favor the formation/accumulation of Fecarb and Femag, a unique feature of marine unsteady depositional regimes. Much lower total Fe(II) contents in the SYS than in the ECS suggest that lower availability of highly reactive Fe (FeHR) and/or weak Fe reduction is a factor limiting Fe(II) formation and accumulation in the SYS sediments. The ratio of FeHR to total Fe is, on average, markedly higher (2.4 times) in the ECS sediments than in the SYS, which may be a combined result of several factors relevant to different sediment sources and depositional/diagenetic settings. In comparison with many other marine sediments, the percent fractions (fFe-OC) of Fe-OC to total organic carbon (TOC) in the ECS and the SYS are low, which can be ascribed to surface adsorption of OC rather than coprecipitation or organic complexation as the dominant binding mechanisms. Based on the fFe-OC in this study, total Fe-OC estimated for global continental shelves is equivalent to 38% of the atmospheric CO2 pool, which indicates the important role of sorptive stabilization of Fe-OC in continental shelf sediments for buffering CO2 release to the atmosphere

  18. Evaluation of harvest and information needs for North American sea ducks.

    Science.gov (United States)

    Koneff, Mark D; Zimmerman, Guthrie S; Dwyer, Chris P; Fleming, Kathleen K; Padding, Paul I; Devers, Patrick K; Johnson, Fred A; Runge, Michael C; Roberts, Anthony J

    2017-01-01

    Wildlife managers routinely seek to establish sustainable limits of sport harvest or other regulated forms of take while confronted with considerable uncertainty. A growing body of ecological research focuses on methods to describe and account for uncertainty in management decision-making and to prioritize research and monitoring investments to reduce the most influential uncertainties. We used simulation methods incorporating measures of demographic uncertainty to evaluate risk of overharvest and prioritize information needs for North American sea ducks (Tribe Mergini). Sea ducks are popular game birds in North America, yet they are poorly monitored and their population dynamics are poorly understood relative to other North American waterfowl. There have been few attempts to assess the sustainability of harvest of North American sea ducks, and no formal harvest strategy exists in the U.S. or Canada to guide management. The popularity of sea duck hunting, extended hunting opportunity for some populations (i.e., special seasons and/or bag limits), and population declines have led to concern about potential overharvest. We used Monte Carlo simulation to contrast estimates of allowable harvest and observed harvest and assess risk of overharvest for 7 populations of North American sea ducks: the American subspecies of common eider (Somateria mollissima dresseri), eastern and western populations of black scoter (Melanitta americana) and surf scoter (M. perspicillata), and continental populations of white-winged scoter (M. fusca) and long-tailed duck (Clangula hyemalis). We combined information from empirical studies and the opinions of experts through formal elicitation to create probability distributions reflecting uncertainty in the individual demographic parameters used in this assessment. Estimates of maximum growth (rmax), and therefore of allowable harvest, were highly uncertain for all populations. Long-tailed duck and American common eider appeared to be at high

  19. Structural geology of the North and Middle Caspian sea on the new geophysical data interpretation

    International Nuclear Information System (INIS)

    Boris, V.S; Rais, V.Sh; Victor, L.U

    2002-01-01

    Full text:A structural and tectonic map of the North and Middle Caspian Sea is made on the basis of seismic and other geological and geophysical data analysis. According to the plotting results the total amplitude range of the heterogeneous basement depths are in the North Caspian Sea (Ukatnensky depression-over 12 km and Prorva depression-over 16 km). In the middle Caspian Sea the deppest basement point is supposed in Sulak basin (over 12 km). The least basement depths are marked in Karpinsky ridge,Buzachinky and Karabogazsky arches (1-3 km). On the whole the morphology and structure of the basement confirms the conclusion previously made by many researches that the Caspian Sea is a heterogeneous depression superimposed on the junction of regional tectonic elements of various ages.The ancient East-European platform represented by Pricaspiisky depression (Donetsko-Astrakhanskaya fault system limits the latter in the south) is situated on the North. The middle Caspian Sea is occupied with the offshore continuation of Terek-Caspian foredeep is represented by Sulak basin clearly limited in the south by a system of upthrusts and thrusts falling under North Caucasus foreland.Geological interpretation of the Yuzhmorgeologiya Center new geophysical data allows making an assumption about the biohermexistence within TriassicSea sediments on Kuma-Manychsky depression offshore continuation. Seismic exploration works show strike-slip faults and thrust structure development within the sedimentary cover on the offshore continuation of Karpinsky ridge.Some strike-slipped blocks are separated by left-side shifts of the northeast stretch.The pool location at the left-side (east) blocks of the shift areas is marked.

  20. Temperature, salinity, oxygen and nutrients bottle and CTD data collected in the northern North Atlantic, Nordic and Arctic Seas from 1901 to 2011 (NODC Accession 0105532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen and nutrients bottle and CTD data collected in the Arctic Ocean, Barents Sea, Greenland Sea, Kara Sea, North Atlantic Ocean,...

  1. 150 years of ecosystem evolution in the North Sea - from pristine conditions to acidification

    Science.gov (United States)

    Pätsch, Johannes; Lorkowski, Ina; Kühn, Wilfried; Moll, Andreas; Serna, Alexandra

    2010-05-01

    The 3-d coupled physical-biogeochemical model ECOHAM was applied to the Northwest European Shelf (47° 41‘ - 63° 53' N, 15° 5' W - 13° 55' E) for the years 1860, 1960 and continuously for the time interval 1970 - 2006. From stable nitrogen isotope analysis in sediment cores of the German Bight in the southeastern part of the North Sea (inner shelf) we found the period before 1860 unaffected by anthropogenic river inputs of nitrogen. After this period the delta15N-ratios significantly increased from ~6 per mil to more than 8 per mil in recent sediments indicating eutrophication by anthropogenic nitrate mainly from intensive agriculture fertilization. We deduced from the successful simulation of delta15N patterns in recent sediments that during pristine conditions nitrogen loads of the main continental rivers were about 10% of the modern input while the deposition of inorganic atmospheric nitrogen was 28% of the recent atmospheric flux. The 1960-sediment exhibited similar delta15N-values as the recent sediment which allows the conclusion that eutrophication in the German Bight predates the 1960 period of rapidly increasing river loads. By comparing model results with observational data in the North Sea we analyzed the variability of simulated carbon fluxes (1970-2006) constituting the so called "shelf pump" which transports atmospheric CO2 via biological fixation, vertical export and advection into the adjacent North Atlantic. Even though the highly variable North Atlantic water-inflow which correlated with the North Atlantic Oscillation Index (NAOI) supplied the northern North Sea with strongly varying nutrient inputs, the interannual variability of the strength of the shelf pump was mainly governed by the variability of the southern basin's biological productivity. The net ecosystem production (NEP) in the southern North Sea varies around zero inducing CO2 exchange with the atmosphere which is near equilibrium. In the northern North Sea the strong positive

  2. Geologic Variable Associated with Height of Yellow-Poplar Stand in the Bald Mountains of North Carolina

    Science.gov (United States)

    W. Henry McNab; Carl E. Merschat

    1990-01-01

    Quartz grain size and mylonitization, geologic variables determined fromrocks on sites, were associated with total height of yellow-poplar (Liriodendron tulipifera L.) standsand may be of value as independent variables in modeling tree growth from site characteristics. A predictive model containing quartz grain site and stand age accounted for about 54% of the...

  3. A UAV and S2A data-based estimation of the initial biomass of green algae in the South Yellow Sea.

    Science.gov (United States)

    Xu, Fuxiang; Gao, Zhiqiang; Jiang, Xiaopeng; Shang, Weitao; Ning, Jicai; Song, Debin; Ai, Jinquan

    2018-03-01

    Previous studies have shown that the initial biomass of green tide was the green algae attaching to Pyropia aquaculture rafts in the Southern Yellow Sea. In this study, the green algae was identified with unmanned aerial vehicle (UAV), an biomass estimation model was proposed for green algae biomass in the radial sand ridge area based on Sentinel-2A image (S2A) and UAV images. The result showed that the green algae was detected highly accurately with the normalized green-red difference index (NGRDI); approximately 1340 tons and 700 tons of green algae were attached to rafts and raft ropes respectively, and the lower biomass might be the main cause for the smaller scale of green tide in 2017. In addition, UAV play an important role in raft-attaching green algae monitoring and long-term research of its biomass would provide a scientific basis for the control and forecast of green tide in the Yellow Sea. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Spatiotemporal variations of inorganic nutrients along the Jiangsu coast, China, and the occurrence of macroalgal blooms (green tides) in the southern Yellow Sea.

    Science.gov (United States)

    Li, Hongmei; Zhang, Yongyu; Tang, Hongjie; Shi, Xiaoyong; Rivkin, Richard B; Legendre, Louis

    2017-03-01

    Large macroalgal blooms (i.e. green tides of Ulva prolifera) occurred in the southern Yellow Sea, China, yearly from 2007 to 2016. They were among the largest of such outbreaks around the world, and these blooms likely originated along the coast of the Jiangsu Province, China. Understanding the roles of nutrients in the onset of these macroalgal blooms is needed to identify their origin. This study analyzes the spatiotemporal variations in dissolved inorganic nitrogen and phosphorus (DIN and PO 4 -P) and the N/P ratio along the Jiangsu coast from 1996 to 2014 during late-March to April, the months which corresponds to the pre-bloom period of green tides since 2007. A zone of high DIN and PO 4 -P concentrations has developed along the Jiangsu coast, between the cities of Sheyang and Nantong, since 1996. There was an 18-year trend of increasing DIN concentrations during the pre-bloom period as well as a positive correlation between the U. prolifera biomass and DIN concentrations. Nutrient inputs from rivers and mariculture in the Jiangsu Province may have provided nitrogen that contributed the magnitude of macroalgal blooms that subsequently spread into the southern Yellow Sea. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Sensitivity of Calanus spp. copepods to environmental changes in the North Sea using life-stage structured models

    DEFF Research Database (Denmark)

    Maar, Marie; Møller, Eva Friis; Gürkan, Zeren

    2013-01-01

    Sea because it allows them to utilize the spring bloom more efficiently and independently of the timing and amount of oceanic inflow. The combination of lower temperatures, higher overwintering and oceanic inflow simulating the situation in the 1960s largely favoured C. finmarchicus and their relative......, overwintering and oceanic inflow in the North Sea. Life-stage structured models are validated against CPR data and vertical distributions north of the Dogger Bank in the North Sea for the reference year 2005. The model shows that 1) ± 2°C changes from the current level mainly influence the seasonal patterns...... and not the relative occurrence of the two species, 2) changes due to oceanic inflow mainly appeared in the northern and southern part of the North Sea connected to the NE Atlantic and not in the central part and 3) the abundance of Calanus species were very sensitive to the degree of overwintering within the North...

  6. RKU North Sea. Update on the regional consequence examination concerning the petroleum industry in the North Sea

    International Nuclear Information System (INIS)

    2006-12-01

    An overview over prognoses for oil and gas production and the emissions related to these activities is provided for the years 2005-2025. A description of the Norwegian Continental Shelf's ecosystem, environmental technology employed, and considerations regarding the petroleum industry's effect on the ecosystem are considered. Emissions to air, planned emissions to the sea and accident emissions and spills are treated, as well as other possible environmental effects. Consequences for fishery, cultural monuments and for the society in general are also examined (ml)

  7. Land-sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

    Science.gov (United States)

    Donders, Timme H.; van Helmond, Niels A. G. M.; Verreussel, Roel; Munsterman, Dirk; ten Veen, Johan; Speijer, Robert P.; Weijers, Johan W. H.; Sangiorgi, Francesca; Peterse, Francien; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.; Lourens, Lucas; Kuhlmann, Gesa; Brinkhuis, Henk

    2018-03-01

    We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (˜ 2.6-1.8 Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG) in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial-interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS) 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST), vegetation, relative sea level, and coastal influence.During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct warm-cold alterations are

  8. Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing

    Directory of Open Access Journals (Sweden)

    T. H. Donders

    2018-03-01

    Full Text Available We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (∼ 2.6–1.8 Ma multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial–interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST, vegetation, relative sea level, and coastal influence.During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct

  9. Climate drift of AMOC, North Atlantic salinity and arctic sea ice in CFSv2 decadal predictions

    Science.gov (United States)

    Huang, Bohua; Zhu, Jieshun; Marx, Lawrence; Wu, Xingren; Kumar, Arun; Hu, Zeng-Zhen; Balmaseda, Magdalena A.; Zhang, Shaoqing; Lu, Jian; Schneider, Edwin K.; Kinter, James L., III

    2015-01-01

    There are potential advantages to extending operational seasonal forecast models to predict decadal variability but major efforts are required to assess the model fidelity for this task. In this study, we examine the North Atlantic climate simulated by the NCEP Climate Forecast System, version 2 (CFSv2), using a set of ensemble decadal hindcasts and several 30-year simulations initialized from realistic ocean-atmosphere states. It is found that a substantial climate drift occurs in the first few years of the CFSv2 hindcasts, which represents a major systematic bias and may seriously affect the model's fidelity for decadal prediction. In particular, it is noted that a major reduction of the upper ocean salinity in the northern North Atlantic weakens the Atlantic meridional overturning circulation (AMOC) significantly. This freshening is likely caused by the excessive freshwater transport from the Arctic Ocean and weakened subtropical water transport by the North Atlantic Current. A potential source of the excessive freshwater is the quick melting of sea ice, which also causes unrealistically thin ice cover in the Arctic Ocean. Our sensitivity experiments with adjusted sea ice albedo parameters produce a sustainable ice cover with realistic thickness distribution. It also leads to a moderate increase of the AMOC strength. This study suggests that a realistic freshwater balance, including a proper sea ice feedback, is crucial for simulating the North Atlantic climate and its variability.

  10. Decadal and multi-decadal variability of Labrador Sea Water in the north-western North Atlantic Ocean derived from tracer distributions: Heat budget, ventilation, and advection

    NARCIS (Netherlands)

    van Aken, H.M.; de Jong, M.F.; Yashayaev, I.

    2011-01-01

    Time series of profiles of potential temperature, salinity, dissolved oxygen, and planetary potential vorticity at intermediate depths in the Labrador Sea, the Irminger Sea, and the Iceland Basin have been constructed by combining the hydrographic sections crossing the sub-arctic gyre of the North

  11. Spatio-temporal variability of the North Sea cod recruitment in relation to temperature and zooplankton.

    Directory of Open Access Journals (Sweden)

    Delphine Nicolas

    Full Text Available The North Sea cod (Gadus morhua, L. stock has continuously declined over the past four decades linked with overfishing and climate change. Changes in stock structure due to overfishing have made the stock largely dependent on its recruitment success, which greatly relies on environmental conditions. Here we focus on the spatio-temporal variability of cod recruitment in an effort to detect changes during the critical early life stages. Using International Bottom Trawl Survey (IBTS data from 1974 to 2011, a major spatio-temporal change in the distribution of cod recruits was identified in the late 1990s, characterized by a pronounced decrease in the central and southeastern North Sea stock. Other minor spatial changes were also recorded in the mid-1980s and early 1990s. We tested whether the observed changes in recruits distribution could be related with direct (i.e. temperature and/or indirect (i.e. changes in the quantity and quality of zooplankton prey effects of climate variability. The analyses were based on spatially-resolved time series, i.e. sea surface temperature (SST from the Hadley Center and zooplankton records from the Continuous Plankton Recorder Survey. We showed that spring SST increase was the main driver for the most recent decrease in cod recruitment. The late 1990s were also characterized by relatively low total zooplankton biomass, particularly of energy-rich zooplankton such as the copepod Calanus finmarchicus, which have further contributed to the decline of North Sea cod recruitment. Long-term spatially-resolved observations were used to produce regional distribution models that could further be used to predict the abundance of North Sea cod recruits based on temperature and zooplankton food availability.

  12. Prevalence and molecular characterisation of Acanthocephala in pinnipedia of the North and Baltic Seas

    Directory of Open Access Journals (Sweden)

    Patrick Waindok

    2018-04-01

    Full Text Available Harbour seals (Phoca vitulina and grey seals (Halichoerus grypus are final hosts of acanthocephalans in the German North and Baltic Seas. Parasitic infections in seals can cause pathological changes, which may result in deteriorated health of the host. Common gastrointestinal parasites of harbour and grey seals are acanthocephalans and a number of 275 of 2460 (11.2% investigated seals from 1996 to 2013 were infected with Corynosoma spp. (Acanthocephala, Polymorphidae. The prevalence showed a wave-like pattern: it increased from 1.2% and 0.4% in 1996 and 1997, respectively, to 23.9% during the second phocine distemper epizootic in 2002 and decreased to 6.2% in 2004. In 2005, prevalence peaked again with 25.0% followed by a decrease to 9.3% in 2009 and an increase to 38.5% in 2012. Statistical analysis revealed that harbour seals originating from the North Sea showed a higher prevalence than grey seals, whereas no significant difference between grey and harbour seals from the Baltic Sea was observed. Furthermore, juvenile pinnipedia from the North Sea were significantly less infected with Corynosoma spp. than seals older than seven month. Molecular species identification as well as phylogenetic relationship analysis among the detected Corynosoma species were achieved by sequencing and comparisons of the ribosomal ITS1-5.8S-ITS2-complex and cytochrome-c-oxidase I gene. Molecular analysis resulted in a newly arranged distribution of Acanthocephala in the North Sea as in contrast to previous studies, C. strumosum could not be confirmed as predominant species. Instead, C. magdaleni and a C. magdaleni isolate (isolate Pv1NS with an atypical number of longitudinal rows of hooks at the proboscis were detected. Furthermore, morphological and molecular analyses indicate the possible finding of a cryptic species (Candidatus Corynosoma nortmeri sp. nov.. Keywords: Acanthocephala, Acantocephalans, Corynosoma, Seals, ITS, Cytochrome-c-oxidase, Marine parasites

  13. Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic

    Science.gov (United States)

    Gardner, B.; Sullivan, P.J.; Epperly, S.; Morreale, S.J.

    2008-01-01

    Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water temperature, region, bottom depth, and target species are all significant predictors of the number of loggerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit. ?? Inter-Research 2008.

  14. Ecologically least vulnerable sites for exploration drilling in the Wadden Sea and the North Sea coastal area

    International Nuclear Information System (INIS)

    Lindeboom, H.J.; Bergman, M.J.N.; De Gee, A.

    1996-01-01

    The Dutch Oil Company (NAM, abbreviated in Dutch) applied for a number of exploration drilling in the Dutch part of the Wadden Sea and the North Sea coastal area. NAM is obliged to draft a so-called MER (environmental impact report) to indicate the most environment-friendly alternative for the test drilling. By order of NAM, NIOZ and the IBN-DLO (Institute for Research on Forests and Nature) analyzed samples of the animal life in all the potential sites. Based on the results of the analyses, literature and expert knowledge the ecologically least vulnerable sites and the ecologically least vulnerable season were selected during a workshop. In this report the results are given of the workshop, the field sample analyses and a sailing trip along the sites

  15. Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)

    International Nuclear Information System (INIS)

    Pham, M.K.; Sanchez-Cabeza, J.A.; Povinec, P.P.; Arnold, D.; Benmansour, M.; Bojanowski, R.; Carvalho, F.P.; Kim, C.K.; Esposito, M.; Gastaud, J.; Gasco, C.L.; Ham, G.J.; Hegde, A.G.; Holm, E.; Jaskierowicz, D.; Kanisch, G.; Llaurado, M.; La Rosa, J.; Lee, S.-H.; Liong Wee Kwong, L.; Le Petit, G.; Maruo, Y.; Nielsen, S.P.; Oh, J.-S.; Oregioni, B.; Palomares, J.; Pettersson, H.B.L.; Rulik, P.; Ryan, T.P.; Sato, K.; Schikowski, J.; Skwarzec, B.; Smedley, P.A.; Tarjan, S.; Vajda, N.; Wyse, E.

    2006-01-01

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides ( 4 K, 137 Cs, 232 Th, 234 U, 235 U, 238 U, 238 Pu, 239+24 Pu and 241 Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides ( 9 Sr, 21 Pb( 21 Po), 226 Ra, 239 Pu, 24 Pu 241 Pu). Less frequently reported radionuclides ( 99 Tc, 129 I, 228 Th, 23 Th and 237 Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units

  16. Post-Glacial Development of Western North Atlantic - Labrador Sea Oceanographic Circulation

    DEFF Research Database (Denmark)

    Sheldon, Christina

    2015-01-01

    The subpolar North Atlantic Ocean – Labrador Sea region is an important site for both oceanographic and atmospheric circulation. The convergence of ocean currents causes downwelling of cold, saline water in the subpolar gyre, helping to drive the world-wide thermohaline circulation system. The main......, the subpolar gyre weakened, which carried less Gulf Stream-derived water to the western North Atlantic Ocean via the West Greenland Current and the Slopewater Current, south of Newfoundland. Changes in the subpolar gyre circulation had developed to be analogous to the modern climate by approximately 2 cal kyr...... surface currents involved in the gyre are the south-flowing, cold and relatively fresh Labrador Current and the north-flowing, warm and relatively saline Gulf Stream. The oceanic front between these two major currents moves north and south, dependent on the relative strengths of the currents, impacting...

  17. Vertical nutrient fluxes, turbulence and the distribution of chlorophyll a in the north-eastern North Sea

    Science.gov (United States)

    Bendtsen, Jørgen; Richardson, Katherine

    2017-04-01

    During summer the northern North Sea is characterized by nutrient rich bottom water masses and nutrient poor surface layers. This explains the distribution of chlorophyll a in the water column where a subsurface maximum, referred to as the deep chlorophyll maximum (DCM), often is present during the growth season. Vertical transport of nutrients between bottom water masses and the well lit surface layer stimulates phytoplankton growth and this generally explains the location of the DCM. However, a more specific understanding of the interplay between vertical transports, nutrient fluxes and phytoplankton abundance is required for identifying the nature of the vertical transport processes, e.g the role of advection versus vertical turbulent diffusion or the role of localized mixing associated with mesoscale eddies. We present results from the VERMIX study in the north-eastern North Sea where nutrients, chlorophyll a and turbulence profiles were measured along five north-south directed transects in July 2016. A high-resolution sampling program, with horizontal distances of 1-10 km between CTD-stations, resolved the horizontal gradients of chlorophyll a across the steep bottom slope from the relatively shallow central North Sea ( 50-80 m) towards the deep Norwegian Trench (>700 m). Low oxygen concentrations in the bottom water masses above the slope indicated enhanced biological production where vertical mixing would stimulate phytoplankton growth around the DCM. Measurements of variable fluorescence (Fv/Fm) showed elevated values in the DCM which demonstrates a higher potential for electron transport in the Photosystem II in the phytoplankton cells, i.e. an indication of nutrient-rich conditions favorable for phytoplankton production. Profiles of the vertical shear and microstructure of temperature and salinity were measured by a VMP-250 turbulence profiler and the vertical diffusion of nutrients was calculated from the estimated vertical turbulent diffusivity and the

  18. Seasonal variation in chromophoric dissolved organic matter and relationships among fluorescent components, absorption coefficients and dissolved organic carbon in the Bohai Sea, the Yellow Sea and the East China Sea

    Science.gov (United States)

    Zhu, Wen-Zhuo; Zhang, Hong-Hai; Zhang, Jing; Yang, Gui-Peng

    2018-04-01

    The absorption coefficient and fluorescent components of chromophoric dissolved organic matter (CDOM) in the Bohai Sea (BS), Yellow Sea (YS), and East China Sea (ECS) in spring and autumn were analyzed in this study. Excitation-emission matrices (EEMs) combined with parallel factor analysis (PARAFAC) identified three components, namely, humic-like C1, tyrosine-like C2 and tryptophan-like C3. The seasonal variations in the vertical patterns of the CDOM absorption coefficient (aCDOM(355)) and fluorescent components were influenced by the seasonal water mass except for the terrestrial input. The relationship between aCDOM(355) and dissolved organic matter (DOC) was attributed to their own mixing behavior. The correlation of the fluorescent components with DOC was disturbed by other non-conservative processes during the export of CDOM to the open ocean. The different chemical compositions and origins of DOC and CDOM led to variability in carbon-specific CDOM absorption (a*CDOM(355)) and fluorescent component ratios (ICn/IC1). The relationship between a*CDOM(355) and aCDOM(355) demonstrated that dissolved organic matter (DOM) in the BS, but not in the ECS, highly contributed non-absorbing DOC to the total DOC concentration. The photodegradation of dominant terrestrially derived CDOM in the ECS contributed to the positive relationship between a*CDOM(355) and ICn/IC1. By contrast, the abundant autochthonous CDOM in the YS was negatively correlated with ICn/IC1 in autumn. Our established box models showed that water exchange is a potentially important source of the aromatic components in the BS, YS, and ECS. Hence, the seasonal variations in water exchange might contribute to the variability of CDOM chemical composition in the BS, YS, and ECS, and significantly influence the structure and function of their ecosystems.

  19. Variability and connectivity of plaice populations from the Eastern North Sea to the Western Baltic Sea, and implications for assessment and management

    DEFF Research Database (Denmark)

    Ulrich, Clara; Boje, Jesper; Cardinale, Massimiliano

    2013-01-01

    and management. Plaice in Kattegat and Skagerrak have traditionally been considered as one stock unit. Current understanding indicates that several plaice components may exist in the transition area between the North Sea and the Baltic Sea. A comprehensive review of all available biological knowledge on plaice...

  20. The Use of the Lead and Line by Early Navigators in the North Sea?

    Directory of Open Access Journals (Sweden)

    John Kemp

    2014-12-01

    Full Text Available This paper draws attention to the lack of information as to how early North Sea sailors navigated, particularly during the one thousand year period that followed Roman times. The lead and line was the only navigational aid available for most of this period, but there is little recorded as to whether it was used simply for ensuring a ship or boat had enough water to proceed or whether, together with the knowledge it provided of the nature of the sea bed, it was used as a more positive position fixing device. The author would appreciate any information relating to navigation techniques used during this period.

  1. Derived concentration factors for caesium-137 in edible species of North Sea fish

    International Nuclear Information System (INIS)

    Steele, A.K.

    1990-01-01

    Concentration factor (CF=Bq kg -1 fillet/Bg kg -1 filtered sea water) values for 137 Cs in fillets of cod (Gadus morhua), haddock (Merlanogrammus aeglefinus), plaice (Pleuronectes platessa) and whiting (Merlangius merlangius), were derived from fish and filtered seawater concentrations. Samples were collected in twelve sampling boxes in the North Sea over an eight-year period - 1978-1985. The range of results with species, between species, and between surveys are discussed. Mean CF values of 92, 58, 39 and 150 were found in cod, haddock, plaice and whiting respectively. These support the International Atomic Energy Authority recommended CF value of 100 for fish in generalised dose assessments. (author)

  2. Origins of wind-driven intraseasonal sea level variations in the North Indian Ocean coastal waveguide

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, I.; Vialard, J.; Lengaigne, M.; Han, W.; Mc; Durand, F.; Muraleedharan, P.M.

    version: Geophys. Res. Lett., vol.40(21); 2013; 5740-5744 Origins of wind-driven intraseasonal sea level variations in the North Indian Ocean coastal waveguide I. Suresh1, J. Vialard2, M. Lengaigne2, W. Han3, J. McCreary4, F. Durand5, P.M. Muraleedharan1... reversing winds. These wind variations drive seasonal equatorial Kelvin and Rossby wave responses. The seasonal equatorial Kelvin waves propagate into the North Indian Ocean (hereafter NIO) as coastal Kelvin waves [McCreary et al., 1993]. As a result...

  3. Sea-ice evaluation of NEMO-Nordic 1.0: a NEMO-LIM3.6-based ocean-sea-ice model setup for the North Sea and Baltic Sea

    Science.gov (United States)

    Pemberton, Per; Löptien, Ulrike; Hordoir, Robinson; Höglund, Anders; Schimanke, Semjon; Axell, Lars; Haapala, Jari

    2017-08-01

    The Baltic Sea is a seasonally ice-covered marginal sea in northern Europe with intense wintertime ship traffic and a sensitive ecosystem. Understanding and modeling the evolution of the sea-ice pack is important for climate effect studies and forecasting purposes. Here we present and evaluate the sea-ice component of a new NEMO-LIM3.6-based ocean-sea-ice setup for the North Sea and Baltic Sea region (NEMO-Nordic). The setup includes a new depth-based fast-ice parametrization for the Baltic Sea. The evaluation focuses on long-term statistics, from a 45-year long hindcast, although short-term daily performance is also briefly evaluated. We show that NEMO-Nordic is well suited for simulating the mean sea-ice extent, concentration, and thickness as compared to the best available observational data set. The variability of the annual maximum Baltic Sea ice extent is well in line with the observations, but the 1961-2006 trend is underestimated. Capturing the correct ice thickness distribution is more challenging. Based on the simulated ice thickness distribution we estimate the undeformed and deformed ice thickness and concentration in the Baltic Sea, which compares reasonably well with observations.

  4. Sea@shore: informational governance in marine spatial conflicts at the North Sea

    NARCIS (Netherlands)

    Toonen, H.M.

    2013-01-01

    Oceans and seas seem to be an empty space and untouched wilderness, but are in fact heavily used and exploited by different economic activities which have, to greater or lesser extent, environmental impacts. Attention for marine environmental challenges has grown, and is nowadays

  5. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    NARCIS (Netherlands)

    Frederikse, Thomas; Riva, R.E.M.; Slobbe, Cornelis; Broerse, D.B.T.; Verlaan, Martin

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by

  6. Estimating decadal variability in sea level from tide gauge records : An application to the North Sea

    NARCIS (Netherlands)

    Frederikse, T.; Riva, R.E.M.; Slobbe, D.C.; Broerse, D.B.T.; Verlaan, M.

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model

  7. Phytoplankton, chemical, physical, and other data were collected using bottle, CTD casts, and other instruments in the North Sea as part of the North Sea Project, 15 April 1988 - 30 July 1991 (NODC Accession 9300008)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Phytoplankton, chemical, physical, and other data were collected using bottle, current meter, net, pump, and CTD casts in the North Sea from April 15, 1988 to July...

  8. Nutrients, chlorophyll, fractional primary productivity in water column of the North Arabian Sea in support of the North Arabian Sea Environment and Ecosystem Research from 1992-1994 (NODC Accession 0000778)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Five cruises were carried out under the Pak-US cooperative project 'North Arabian Sea Environment and Ecosystem Research' (NASEER) from 1992-1994. The main objective...

  9. Integrated management plan for the North Sea and the Skagerrak: Impact assessment for renewable energy production in the North Sea; Helhetlig forvaltningsplan for Nordsjoen og Skagerrak. Konsekvenser av fornybar energiproduksjon i Nordsjoen.

    Energy Technology Data Exchange (ETDEWEB)

    Nybakke, Karen

    2011-07-01

    This is one of six sectorial assessments which will form the basis for a general management plan for the North Sea and the Skagerrak. The (environmental) impact assessment is limited to 6 areas.(Author)

  10. Transport process of Pu isotope in marginal seas of the western North Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masatoshi [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki, 036-8564, Aomori (Japan); Zheng, Jian [Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, 263-8555, Chiba (Japan)

    2014-07-01

    Significant quantities of Pu isotopes have been released into the marine environment as the result of atmospheric nuclear weapons testing. Most radionuclides globally dispersed in atmospheric nuclear weapons testing were released into the environment during the 1950's and 1960's. In the western North Pacific Ocean, the principal source can be further distinguished as two distinct sources of Pu: close-in tropospheric fallout from nuclear weapons testing at the Pacific Proving Grounds (PPG) in the Marshall Islands and global stratospheric fallout. Since the {sup 240}Pu/{sup 239}Pu atom ratio is characteristic for the Pu emission source, information on Pu isotopic signature is very useful to better understand the transport process in the oceans and to identify the sources of Pu. The mean atom ratio of {sup 240}Pu/{sup 239}Pu from the global stratospheric fallout is 0.180 ±0.014 based on soil sample data, whereas that from close-in tropospheric fallout from the PPG is 0.33 - 0.36. The {sup 240}Pu/{sup 239}Pu atom ratios in seawater samples collected in marginal seas of the western North Pacific Ocean will provide important and useful data for understanding the process controlling Pu transport and for distinguishing future Pu sources. The objectives of this study were to measure the {sup 239+240}Pu concentrations and {sup 240}Pu/{sup 239}Pu atom ratios in seawater from the Sea of Okhotsk, Japan Sea, South China Sea and Sulu Sea and to discuss the transport process of Pu. Large-volume seawater samples (250 L each) were collected from the surface to the bottom in marginal seas of the western North Pacific Ocean with acoustically triggered quadruple PVC sampling bottles during the R/V Hakuho-Maru cruise. The {sup 239}Pu and {sup 240}Pu concentrations and {sup 240}Pu/{sup 239}Pu atom ratios were measured with a double-focusing SF-ICP-MS, which was equipped with a guard electrode to eliminate secondary discharge in the plasma and to enhance overall sensitivity. In

  11. Riverine input of organic carbon and nitrogen in water-sediment system from the Yellow River estuary reach to the coastal zone of Bohai Sea, China

    Science.gov (United States)

    Wang, Chuanyuan; Lv, Yingchun; Li, Yuanwei

    2018-04-01

    The temporal-spatial distribution of the carbon and nitrogen contents and their isotopic compositions of suspended matter and sediments from the Yellow River estuary reach (YRER), the estuary to the offshore area were measured to identify the source of organic matter. The higher relative abundances of suspended and sedimentary carbon and nitrogen (POC, TOC, PN and TN) in the offshore marine area compared to those of the riverine and estuarine areas may be due to the cumulative and biological activity impact. The organic matter in surface sediments of YRER, the estuary and offshore area of Bohai Sea is basically the mixture of continental derived material and marine material. The values of δ13Csed fluctuate from values indicative of a land source (- 22.50‰ ± 0.31) to those indicative of a sea source (- 22.80‰ ± 0.38), which can be attributed to the fine particle size and decrease in terrigenous inputs to the offshore marine area. Contrary to the slight increase of POC and PN during the dry season, TOC and TN contents of the surface sediments during the flood season (October) were higher than those during the dry season (April). The seasonal differences in water discharge and suspended sediment discharge of the Yellow River Estuary may result in seasonal variability in TOC, POC, TN and PN concentrations in some degree. Overall, the surface sediments in the offshore area of Bohai Sea are dominated by marine derived organic carbon, which on average, accounts for 58-82% of TOC when a two end-member mixing model is applied to the isotopic data.

  12. Larval growth and drift pattern and the separation of herring spawning groups in the North Sea

    DEFF Research Database (Denmark)

    Munk, Peter; Christensen, Villy

    1990-01-01

    Data from two internationally co-ordinated survey programmes are used in an attempt to display the events in the early life that took place during the 'recovery period' of the North Sea herring stock, 1979-1986. During the period, an increasing importance of the spawning grounds off Buchan and off...... Yorkshire is evident from distributions of newly hatched herring larvae. The dramatic changes in relative importance of spawning grounds are traced in the data on both late larvae (6 months old) and juveniles (18 months old). The onset of extended spawning off Buchan and off Yorkshire was followed...... in the relative contributions from spawning grounds apparently influence the overall spatial distribution as well as size composition of larval and juvenile North Sea herring. The findings indicate that groups of larvae retain, to a large extent, separate distributions until metamorphosis, and point to larval...

  13. Assessments of the lesser sandeel ( Ammodytes marinus ) in the North Sea based on revised stock divisions

    DEFF Research Database (Denmark)

    Pedersen, S.A.; Lewy, Peter; Wright, P.

    1999-01-01

    effort, catch per unit effort, yield, fishing and natural mortality. A better understanding of sandeel growth is important for stock and catch predictions because previous studies indicate that the variability of mean weight-at-age is one of the most important factors influencing the precision......Recent investigations suggest that the current treatment of North Sea sandeel (Ammodytes marinus) as a single unit stock may have little biological basis. In order to study regional effects of the fishery on North Sea lesser sandeel it may therefore be important to assess stock dynamics...... of predictions. The Danish weight-at-age data of sandeel are re- analysed to estimate the mean weight-at-age in the catch and the stock and the precision of the estimates. The reliability of the sandeel assessments is discussed in relation to the data sources available and to the knowledge of sandeel biology...

  14. Spectral Properties of ENVISAT ASAR and QuikSCAT Surface Winds in the North Sea

    DEFF Research Database (Denmark)

    Karagali, Ioanna; Larsén, Xiaoli Guo; Badger, Merete

    2013-01-01

    as an increase in spectral density over similar wavenumber ranges as the spatial resolution increases. The 600-m SAR wind product reveals a range of wavenumbers in which the exchange processes between micro- and meso-scales occur; this range is not captured by the wind products with a resolution of 1.5 km......Spectra derived from ENVISAT Advanced Synthetic Aperture Radar (ASAR) and QuikSCAT near-surface ocean winds are investigated over the North Sea. The two sensors offer a wide range of spatial resolutions, from 600 m to 25 km, with different spatial coverage over the area of interest. This provides...... a unique opportunity to study the impact of the spatial resolution on the spectral properties of the wind over a wide range of length scales. Initially, a sub-domain in the North Sea is chosen, due to the overlap of 87 wind scenes from both sensors. The impact of the spatial resolution is manifested...

  15. Recruitment decline in North Sea herring is accompanied by reduced larval growth rates

    DEFF Research Database (Denmark)

    Payne, Mark; Ross, Stine Dalmann; Worsøe Clausen, Lotte

    2013-01-01

    The stock of North Sea autumn spawning herring (Clupea harengus L.) has shown an unprecedented sequence of ten years of sharply reduced recruitment, in spite of a high spawning biomass. Recent work has identified this below-expected recruitment as being determined during the larval phase: however...... rate of 8%, concurrent with the reduced larval survival and recruitment, was identified: after correcting for the effect of other explanatory variables (e.g. temperature changes), the gross reduction was found to be 12%. This reduction is most probably due to changes in either the amount or quality...... and larvae survival, thereby narrowing the range of potential mechanisms underlying the observed reduction in the recruitment of North Sea autumn spawning herring...

  16. Closing the Gaps in Offshore P&A: Lessons Learned From the North Sea

    Science.gov (United States)

    Torsater, M.

    2017-12-01

    This talk will give an overview of the major challenges related to offshore well plugging and abandonment (P&A) with examples from the North Sea. The talk will outline why today's P&A operations are so time consuming and expensive, and it will point out current technology gaps and issues related to standards and regulations in the North Sea countries. Emerging P&A solutions will be discussed, and results from large ongoing research projects in Norway will be shared. Special emphasis will be given to promising new concepts, such as using creeping shale formations as permanent well barriers, and using thermal methods for removal of tubing and casing. The long-term aspects of well plugging will also be discussed, together with methods available for minimizing leakage risk.

  17. Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria.

    Science.gov (United States)

    Hermsen, Enya; Pompe, Renske; Besseling, Ellen; Koelmans, Albert A

    2017-09-15

    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of >20μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a Sprat) out of 400 individuals (0.25%, with a 95% confidence interval of 0.09-1.1%). The particles were identified to consist of polymethylmethacrylate (PMMA) through FTIR spectroscopy. No contamination occurred during the study, showing the method applied to be suitable for microplastic ingestion studies in biota. We discuss the low particle count for North Sea fish with those in other studies and suggest a relation between reported particle count and degree of quality assurance applied. Microplastic ingestion by fish may be less common than thought initially, with low incidence shown in this study, and other studies adhering to strict quality assurance criteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Early Permian intrusions in the Paleozoic sediments of the Eastern North Sea area

    DEFF Research Database (Denmark)

    Clausen, O.R.; Andresen, Katrine Juul; Rasmussen, Jens Andreas

    in the Northern Permian Basin which in the eastern North Sea is separated from the Southern Permian Basin by the Ringkøbing-Fyn High. The Permian basins were initiated during thermal subsidence following a late Carboniferous- early Permian rifting phase associated with extensive igneous activity recorded across...... the entire North Sea Basin. The easternmost intrusions and extrusions have been associated to the “Skagerrak-Centered Large Igneous Province” that has an early Permian age of c. 297 Ma. Compared to the Southern Permian Basin which historically has been intensely investigated because of the known presence...... of hydrocarbons within the Paleozoic sediments, the Northern Permian Basin has gained much less interest outside the hydrocarbon producing Mesozoic graben systems. This is mainly due to an apparent lack of potential source rocks. A major E-W striking northward dipping fault system characterizes the study area...

  19. Shifts in North Sea forage fish productivity and potential fisheries yield

    DEFF Research Database (Denmark)

    Worsøe Clausen, Lotte; Rindorf, Anna; van Deurs, Mikael

    2018-01-01

    productivity. Furthermore, from an ecosystem-based fisheries management perspective, a link between functional complementarity and productivity, indicates that ecosystem resilience may decline with productivity. Based on this, we advise that system productivity, perhaps monitored as forage fish growth, becomes......1. Forage fish populations support large scale fisheries and are key components of marine ecosystems across the world, linking secondary production to higher trophic levels. While climate-induced changes in the North Sea zooplankton community are described and documented in literature......, the associated bottom-up effects and consequences for fisheries remain largely unidentified. 2. We investigated the temporal development in forage fish productivity and the associated influence on fisheries yield of herring, sprat, Norway pout and sandeel in the North Sea. Using principal component analysis, we...

  20. Mixed fisheries forecasts—lessons learned from their initial application to North Sea fisheries

    DEFF Research Database (Denmark)

    Holmes, S.J.; Ulrich, Clara; Reeves, S.A.

    2012-01-01

    the work with the existing single‐stock assessments. The explicit representation of the complexity of the fisheries also raises questions about the extent to which mixed fisheries science can be used to give ”advice” in the traditional sense. This paper addresses the challenges and issues that have arisen......Mixed fisheries and technical interactions in European fisheries have been a subject of research for many years. The establishment in 2010 of an ICES Working Group tasked with producing annual mixed fisheries forecasts and advice for North Sea demersal fisheries represents a commitment to use...... these approaches in routine scientific advice for the first time. The demersal fisheries of the North Sea provide a particularly interesting context for this work because of their high complexity in terms of the numbers of fleets, gears, métiers, and species involved, and also because mixedfishery effects have...

  1. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

  2. Postglacial sedimentary regime around northern Sylt, South-eastern North Sea, based on shallow seismic evidence

    DEFF Research Database (Denmark)

    Boldreel, Lars Ole; Kuijpers, Antoon; Madsen, Emil B

    2010-01-01

    , in the outer delta, a dune field suggesting westerly-directed sediment transport is identified. The two dune fields appear to be separated by minor indefinite bed forms. The northern part of the Lister Tief is characterised by the presence of a channel with a depth of 20-30 mbsf (meter below sea level) (30......-40 msec TWT (Two Way Traveltime)) and displaying erosion towards the north. At the western termination of the channel the sediment transport pathway appears to be divided into two directions; one towards the outer delta, and one towards the sediment depocenter SW of Rømø. The Lister Ley is characterized......During the past 5 years the coastal zone offshore the northern part of the island of Sylt, has been investigated by sparker seismics and high-resolution subbottom profiling. The North Sea sector of the area is characterized by northward-directed sediment bypass as a result of strong long...

  3. Finance and North Sea oil: the challenge of non-recourse finance

    Energy Technology Data Exchange (ETDEWEB)

    White, N A

    1976-04-01

    Many companies operating in the North Sea feel that the financial community is not responding to the complexity of their situation brought about by the interplay between national legislation and fiscal measures, technological development, extreme weather conditions, OPEC decisions, or falling oil demand. The financial community feels it is lending its depositors' money and the kind of innovations required by some companies in the oil industry would reduce its level of security. After reviewing the possible solutions, the author concludes that it is highly unlikely that non-resource finance in large amounts will be available without collateral, or other security, from outside the North Sea area. The author offers his suggestion and preference for a new kind of vehicle to be designed by the financial institutions that would provide the necessary guarantees to the lending consortium in accordance with the needs of the individual participant in the license or field project. (MCW)

  4. Temperature Effects on Stiffness Moduli of Reservoir Sandstone from the Deep North Sea

    DEFF Research Database (Denmark)

    Orlander, Tobias; Andreassen, Katrine Alling; Fabricius, Ida Lykke

    We investigate effect of testing temperature on the dynamic frame stiffness of quartz-bearing North Sea sandstone from depths of 5 km. We show that at low stress levels, the rock frame stiffens with increasing temperature and we propose an explanation for the controlling mechanisms. While...... temperature. This is unfortunate and hence, we designed a testing program with the intension of separating and quantifying effects of temperature and stress, specifically for the sandstone material subject to this study....

  5. Simulated North Atlantic-Nordic Seas water mass exchanges in an isopycnic coordinate OGCM

    OpenAIRE

    Nilsen, Jan Even Øie; Gao, Yongqi; Drange, Helge; Furevik, Tore; Bentsen, Mats

    2003-01-01

    The variability in the volume exchanges between the North Atlantic and the Nordic Seas during the last 50 years is investigated using a synoptic forced, global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The simulated volume fluxes agree with the existing observations. The net volume flux across the Faroe-Shetland Channel (FSC) is positively correlated with the net flux through the Denmark Strait (DS; R = 0.74 for 3 years low pass filtering), but negatively correlated with ...

  6. Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Franeker, Jan A. van, E-mail: Jan.vanfraneker@wur.nl [IMARES Institute for Marine Resources and Ecosystem Studies, Wageningen-UR, PO Box 167, 1790AD Den Burg, Texel (Netherlands); Blaize, Christine [Le CHENE, Centre de Sauvegarde de la Faune Sauvage et Musee de la Nature, 12 Rue du Musee, F-76190 Allouville-Bellefosse (France); Danielsen, Johannis [Norouri i Sundum 7, FO-410 Kollafjorour (Faroe Islands); Fairclough, Keith [Fairclough Ecological Orkney FEO Viewforth, Swannay by Evie, Orkney, KW17 2NR, Scotland (United Kingdom); Gollan, Jane [Kermouroux, FR-56 470 Saint Philibert (France); Guse, Nils [Research and Technology Centre West coast FTZ, University of Kiel, Hafentoern 1, D-25761 Buesum (Germany); Hansen, Poul-Lindhard [Naturhistorisk Museum Skagen, Skagen Naturcenter, Flagbakkevej 30, DK-9990 Skagen (Denmark); Heubeck, Martin [University of Aberdeen (SOTEAG), Sumburgh Head Lighthouse, Virkie, Shetland ZE3 9JN, Scotland (United Kingdom); Jensen, Jens-Kjeld [Zoological conservator, I Geilini 37, FO-270 Nolsoy (Faroe Islands); Le Guillou, Gilles [Groupe Ornithologique Normand, 118 route d' ORCHER, F-76700 Gonfreville l' Orcher (France); Olsen, Bergur [Faroe Marine Research Institute c/o Natturugripasavnio, Futalag 40, FO-100 Torshavn (Faroe Islands); Olsen, Kare-Olav [Postveien 43, N-4563 Borhaug (Norway); Pedersen, John [Skagen Uddannelsescenter SUC, Vestmolen 15, DK-9990 Skagen (Denmark); Stienen, Eric W.M. [Research Institute for Nature and Forest, Kliniekstraat 25, B-1070 Brussels (Belgium); Turner, Daniel M. [9 Haswell Gardens, North Shields, Tyne and Wear, NE30 2DP, England (United Kingdom)

    2011-10-15

    The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of plastic in the stomach. During 2003-2007, 95% of 1295 fulmars sampled in the North Sea had plastic in the stomach (on average 35 pieces weighing 0.31 g) and the critical level of 0.1 g of plastic was exceeded by 58% of birds, with regional variations ranging from 48 to 78%. Long term data for the Netherlands since the 1980s show a decrease of industrial, but an increase of user plastics, with shipping and fisheries as the main sources. The EcoQO is now also used as an indicator for Good Environmental Status in the European Marine Strategy Framework Directive. - Highlights: > Trends in marine debris can be monitored by plastics in stomachs of seabirds. > In the North Sea 95% of Fulmars has plastic in the stomach (35 particles; 0.31 g). > The policy target is that less than 10% of Fulmars has over 0.1 g of plastic. > Currently 58% of North Sea fulmars exceeds the 0.1 g critical limit. > Over the past 30 years industrial plastics decreased and user plastic increased. - Trends and patterns in the abundance of plastics in northern fulmar stomachs show that seabirds can be a valuable tool for monitoring marine litter.

  7. What can we learn from the stock collapse and recovery of North Sea herring? A review

    DEFF Research Database (Denmark)

    Dickey-Collas, M.; Nash, R.D.M.; Brunel, T.

    The collapse and recovery of North Sea herring in the latter half of the twentieth century hasbeen well documented. With hindsight and the benefit of almost 40 years of extra data andstudies, we can now obtain a clear view of the impact of the collapse and the recovery onthe stock, the fishery, a...... the relevant lessons for the management of other fish stocks and other marine shelf ecosystems...

  8. Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea

    International Nuclear Information System (INIS)

    Franeker, Jan A. van; Blaize, Christine; Danielsen, Johannis; Fairclough, Keith; Gollan, Jane; Guse, Nils; Hansen, Poul-Lindhard; Heubeck, Martin; Jensen, Jens-Kjeld; Le Guillou, Gilles; Olsen, Bergur; Olsen, Kare-Olav; Pedersen, John; Stienen, Eric W.M.; Turner, Daniel M.

    2011-01-01

    The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of plastic in the stomach. During 2003-2007, 95% of 1295 fulmars sampled in the North Sea had plastic in the stomach (on average 35 pieces weighing 0.31 g) and the critical level of 0.1 g of plastic was exceeded by 58% of birds, with regional variations ranging from 48 to 78%. Long term data for the Netherlands since the 1980s show a decrease of industrial, but an increase of user plastics, with shipping and fisheries as the main sources. The EcoQO is now also used as an indicator for Good Environmental Status in the European Marine Strategy Framework Directive. - Highlights: → Trends in marine debris can be monitored by plastics in stomachs of seabirds. → In the North Sea 95% of Fulmars has plastic in the stomach (35 particles; 0.31 g). → The policy target is that less than 10% of Fulmars has over 0.1 g of plastic. → Currently 58% of North Sea fulmars exceeds the 0.1 g critical limit. → Over the past 30 years industrial plastics decreased and user plastic increased. - Trends and patterns in the abundance of plastics in northern fulmar stomachs show that seabirds can be a valuable tool for monitoring marine litter.

  9. The discard ban and its impact on the MSY objective on fisheries-the North Sea

    DEFF Research Database (Denmark)

    Ulrich, Clara

    2016-01-01

    North Sea fisheries are characterised by numerous biological and technical interactions, which create difficulties in identifying MSY targets and achieving those for all stocks simultaneously. The landing obligation may reinforce these issues, as ‘choke’ effects might be triggered by the least...... productive stocks. A flexible management approach can help achieve the multiple objectives, but this requires trade-offs to be made. The ecological benefits of reducing fishing mortality are likely larger than those from the landing obligation itself...

  10. Polonium-210 in mussels and fish from the Baltic-North Sea estuary

    DEFF Research Database (Denmark)

    Dahlgaard, H.

    1996-01-01

    Polonium-210 has been measured in Danish fish meat caught in the North Sea, the Kattegat and the Baltic in 1991-1994. Average values of 0.35, 0.65 and 0.96 Bq Po-210 kg(-1) fresh weight were observed for cod, herring and plaice fillets, respectively. The difference between species is statistically...... in fish and mussels may represent a natural baseline. Copyright (C) 1996 Elsevier Science Ltd....

  11. CO2 enhanced oil recovery and storage in the North Sea - a UK perspective

    International Nuclear Information System (INIS)

    Beckly, Andy; Hughes, David S.

    2006-01-01

    Considerable technical and economic challenges must be overcome if the potential for CO 2 injection and sequestration is to be fully realised. However, there is an opportunity to exploit the synergy between the need to reduce CO 2 emissions and the potential to use CO 2 to increase North Sea oil reserves and extend the life of the basin. This opportunity is available now, while the infrastructure remains in place

  12. Larval nematodes in stomach wall granulomas of smelt Osmerus eperlanus from the German North Sea coast

    OpenAIRE

    Obiekezie, A. I.; Lick, Roland R.; Kerstan, Susanne L.; Möller, Heino

    1992-01-01

    Occurrence of stomach wall granulomas in European smelt was studled at 6 locations along the German North Sea coast. Identification of larval nematodes inhabiting these granulomas is provided for the first time. Three species, isolated by pepsin-HC1 digestion, are involved: Hysterothylacium cf. cornutum, Cosmocephalus obvelatus and Paracuaria tridentata. 72% of all stomachs examined were affected. The ratio of number of granulomas to number of the 3 larval species free in the mesentery was 1:...

  13. Effects of wave-induced forcing on a circulation model of the North Sea

    Science.gov (United States)

    Staneva, Joanna; Alari, Victor; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian

    2017-04-01

    The effect of wind waves on water level and currents during two storms in the North Sea is investigated using a high-resolution NEMO model forced with fluxes and fields from a high-resolution wave model. The additional terms accounting for wave-current interaction that are considered in this study are the Stokes-Coriolis force and the sea-state dependent energy and momentum fluxes. The individual and collective role of these processes is quantified and the results are compared with a control run without wave effects as well as against current and water level measurements from coastal stations. We find a better agreement with observations when the circulation model is forced by sea-state dependent fluxes, especially in extreme events. The two extreme events, the storm Christian (25-27 October 2013), and about a month later, the storm Xaver (5-7 December 2013), induce different wave and surge conditions over the North Sea. Including the wave effects in the circulation model for the storm Xaver raises the modelled surge by more than 40 cm compared with the control run in the German Bight area. For the storm Christian, a difference of 20-30 cm in the surge level between the wave-forced and the stand-alone ocean model is found over the whole southern part of the North Sea. Moreover, the modelled vertical velocity profile fits the observations very well when the wave forcing is accounted for. The contribution of wave-induced forcing has been quantified indicating that this represents an important mechanism for improving water level and current predictions.

  14. Role of North Indian Ocean Air-Sea Interaction in Summer Monsoon Intraseasonal Oscillation

    Science.gov (United States)

    Zhang, L.; Han, W.; Li, Y.

    2017-12-01

    Air-sea coupling processes over the North Indian Ocean associated with Indian summer monsoon intraseasonal oscillation (MISO) are analyzed. Observations show that MISO convection anomalies affect underlying sea surface temperature (SST) through changes in surface shortwave radiation (via cloud cover change) and surface latent heat flux (associated with surface wind speed change). In turn, SST anomalies determine the changing rate of MISO precipitation (dP/dt): warm (cold) SST anomalies cause increasing (decreasing) precipitation rate through increasing (decreasing) surface convergence. Air-sea interaction gives rise to a quadrature relationship between MISO precipitation and SST anomalies. A local air-sea coupling model (LACM) is established based on these observed physical processes, which is a damped oscillatory system with no external forcing. The period of LACM is proportional to the square root of mean state mixed layer depth , assuming other physical parameters remain unchanged. Hence, LACM predicts a relatively short (long) MISO period over the North Indian Ocean during the May-June monsoon developing (July-August mature) phase when is shallow (deep). This result is consistent with observed MISO statistics. An oscillatory external forcing of a typical 30-day period is added to LACM, representing intraseasonal oscillations originated from the equatorial Indian Ocean and propagate into the North Indian Ocean. The period of LACM is then determined by both the inherent period associated with local air-sea coupling and the period of external forcing. It is found that resonance occurs when , amplifying the MISO in situ. This result explains the larger MISO amplitude during the monsoon developing phase compared to the mature phase, which is associated with seasonal cycle of . LACM, however, fails to predict the observed small MISO amplitude during the September-October monsoon decaying phase, when is also shallow. This deficiency might be associated with the

  15. Contrasting records of sea-level change in the eastern and western North Atlantic during the last 300 years

    Science.gov (United States)

    Long, A. J.; Barlow, N. L. M.; Gehrels, W. R.; Saher, M. H.; Woodworth, P. L.; Scaife, R. G.; Brain, M. J.; Cahill, N.

    2014-02-01

    We present a new 300-year sea-level reconstruction from a salt marsh on the Isle of Wight (central English Channel, UK) that we compare to other salt-marsh and long tide-gauge records to examine spatial and temporal variability in sea-level change in the North Atlantic. Our new reconstruction identifies an overall rise in relative sea level (RSL) of c. 0.30 m since the start of the eighteenth century at a rate of 0.9±0.3 mm yr. Error-in-variables changepoint analysis indicates that there is no statistically significant deviation from a constant rate within the dataset. The reconstruction is broadly comparable to other tide-gauge and salt-marsh records from the European Atlantic, demonstrating coherence in sea level in this region over the last 150-300 years. In contrast, we identify significant differences in the rate and timing of RSL with records from the east coast of North America. The absence of a strong late 19th/early 20th century RSL acceleration contrasts with that recorded in salt marsh sediments along the eastern USA coastline, in particular in a well-dated and precise sea-level reconstruction from North Carolina. This suggests that this part of the North Carolina sea level record represents a regionally specific sea level acceleration. This is significant because the North Carolina record has been used as if it were globally representative within semi-empirical parameterisations of past and future sea-level change. We conclude that regional-scale differences of sea-level change highlight the value of using several, regionally representative RSL records when calibrating and testing semi-empirical models of sea level against palaeo-records. This is because by using records that potentially over-estimate sea-level rise in the past such models risk over-estimating sea-level rise in the future.

  16. Investigation and evaluation of airborne pollution in the framework of PARCOM (North Sea) and HELCOM (Baltic Sea) - subproject: Measurements of trace metals

    International Nuclear Information System (INIS)

    Schneider, B.

    1993-01-01

    On the basis of measurements of the deposition and concentrations of atmospheric trace metals the annual input of some selected elements (Pb, Zn, Cd, Ni, V) into the North Sea and the Baltic Sea was estimated. For the Baltic Sea, deposition measurements with a buoy system in the Kiel Bight and data from the EGAP(HELCOM)-monitoring network were used. Data from the measurement stations were extrapolated to related sub-basins according to the deposition fields obtained from model calculations (EMEP). For the North Sea, a mean atmospheric trace metal distribution was determined from numerous measurements at a coastal site and over the central North Sea and the annual input was calculated by multiplication with corresponding deposition velocities and scavenging ratios. A comparison of the deposition data based on measurements with those from model calculations show good agreement in the case of Pb in the Baltic Sea as well as in the North Sea. However, for Zn and Cd large discrepancies are observed. Additionally, deposition processes were studied. Scavenging ratios were determined and dry deposition velocities were estimated by the use of a new method for high time resolution measurements of atmospheric trace metal concentrations (impactor/TXRF). (orig.). 9 figs., 14 tabs [de

  17. Analysis of tidal currents in the North Sea from shipboard acoustic Doppler current profiler data

    Science.gov (United States)

    Vindenes, Håvard; Orvik, Kjell Arild; Søiland, Henrik; Wehde, Henning

    2018-06-01

    North Sea tidal currents are determined by applying harmonic analysis to ship-borne acoustic Doppler current profiler data recorded from 1999 to 2016, covering large areas of the northern North Sea. Direct current measurement data sets of this magnitude are rare in the otherwise well investigated North Sea, and thus it is a valuable asset in studying and expanding our understanding of its tidal currents and circulation in general. The harmonic analysis is applied to a least squares fit of the current observations at a set of knot points. Results from the harmonic analysis compare favorably to tidal parameters estimated from observations from moored instruments. The analysis shows that the tides are characterized by strong semi-diurnal component, with amplitudes of the principal Lunar constituent ranging from 1.6 cm/s in the Skagerrak to 67 cm/s in the Fair Isle Channel. Diurnal tides are found to be approximately one fifth the strength of the predominant semi-diurnal constituent. Output from a regional barotropic tide model compares well to tidal current determined from the harmonic analysis of the Acoustic Doppler Current Profiler data.

  18. The North Seas Countries' Offshore Grid Initiative. Initial Findings. Final Report. Working Group 1 - Grid Configuration

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-15

    This report focuses on the tasks and results from Working Group 1 (WG1), grid configuration and integration, chaired jointly by representatives from Denmark and the Netherlands. The methodology, assumptions concerning generation portfolio, load situation, available technology and results are presented. This report presents the WG1 Offshore Grid Study that supports the North Seas Countries' Offshore Grid Initiative (NSCOGI) final report. The information contained in this report aims to evaluate the long-term development of an offshore grid structure in the North Seas by providing a view on how such a grid may possibly develop in the future, based on the assumptions made for this study. The report aims to compare and evaluate the possible advantages and disadvantages of the long term development of an optimised, integrated (or meshed) offshore grid in the North Seas by providing a view of how that possible grid might develop in the future against changes to the electricity energy requirements. To evaluate basic variants, different transmission design topologies (radial and meshed) were compared and analysed with respect to various aspects, such as cost/benefits, import and export levels and the systems' CO2 emissions.

  19. Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means.

    Science.gov (United States)

    Fox, Clive J; Taylor, Martin; Dickey-Collas, Mark; Fossum, Petter; Kraus, Gerd; Rohlf, Norbert; Munk, Peter; van Damme, Cindy J G; Bolle, Loes J; Maxwell, David L; Wright, Peter J

    2008-07-07

    Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey to cover the whole North Sea. Also, this survey, conducted in 2004, was the first to make extensive use of DNA-based molecular methods to unambiguously identify early developmental stage cod eggs. We compare the findings from the plankton survey with estimated egg production inferred from the distribution of mature cod in contemporaneous trawl surveys. Results from both approaches were in general agreement and showed hot spots of egg production around the southern and eastern edges of the Dogger Bank, in the German Bight, the Moray Firth and to the east of the Shetlands. These areas broadly coincide with known spawning locations from the period 1940 to 1970. We were, however, unable to directly detect significant numbers of cod eggs at the historic spawning ground off Flamborough (northeast coast of England). The results demonstrate that most of the major spawning grounds of cod in the North Sea are still active but that some localized populations may have been reduced to the point where it is now difficult to detect the presence of eggs in the plankton.

  20. Organophosphorus flame retardants and plasticizers in the atmosphere of the North Sea

    International Nuclear Information System (INIS)

    Moeller, Axel; Xie Zhiyong; Caba, Armando; Sturm, Renate; Ebinghaus, Ralf

    2011-01-01

    Air samples collected in the German part of the North Sea from March to July 2010 were investigated for organophosphorus compounds (OPs) being applied as flame retardants and plasticizers. The Σ 8 OPs concentration ranged from 110 to 1400 pg m -3 while tris(2-chloroisopropyl) phosphate (TCPP) dominated all samples with individual concentrations up to 1200 pg m -3 . The highest concentrations were observed in continental air masses showing the high influence of industrialized regions including production sites on atmospheric emissions and concentrations. The occurrence of OPs even in oceanic/Arctic air masses shows that OPs can undergo long-range atmospheric transport. Dry particle-bound deposition fluxes from 9 to 240 ng m -2 d -1 for Σ 8 OPs were estimated leading to a minimum annual flux of 710 ± 580 kg y -1 OPs into the German North Sea. This study presents the first occurrence of OPs in the marine atmosphere together with important information on their long-range transport potential. - Highlights: → Organophosphorus flame retardants are detected for the first time in the marine atmosphere. → Organophosphorus compounds can undergo medium to long-range atmospheric transport. → Western Europe emits organophosphorus compounds to the marine atmosphere. → Marine air levels of organophosphorus flame retardants range up to 1 ng/m 3 . - Organophosphorus flame retardants, in particular tris(2-chloroisopropyl) phosphate, are emitted into the North Sea atmosphere by Western European countries.

  1. Integrated North Sea grids: The costs, the benefits and their distribution between countries

    International Nuclear Information System (INIS)

    Konstantelos, Ioannis; Pudjianto, Danny; Strbac, Goran; De Decker, Jan; Joseph, Pieter; Flament, Aurore; Kreutzkamp, Paul; Genoese, Fabio; Rehfeldt, Leif; Wallasch, Anna-Kathrin; Gerdes, Gerhard; Jafar, Muhammad; Yang, Yongtao; Tidemand, Nicolaj; Jansen, Jaap; Nieuwenhout, Frans; Welle, Adriaan van der; Veum, Karina

    2017-01-01

    A large number of offshore wind farms and interconnectors are expected to be constructed in the North Sea region over the coming decades, creating substantial opportunities for the deployment of integrated network solutions. Creating interconnected offshore grids that combine cross-border links and connections of offshore plants to shore offers multiple economic and environmental advantages for Europe's energy system. However, despite evidence that integrated solutions can be more beneficial than traditional radial connection practices, no such projects have been deployed yet. In this paper we quantify costs and benefits of integrated projects and investigate to which extent the cost-benefit sharing mechanism between participating countries can impede or encourage the development of integrated projects. Three concrete interconnection case studies in the North Sea area are analysed in detail using a national-level power system model. Model outputs are used to compute the net benefit of all involved stakeholders under different allocation schemes. Given the asymmetric distribution of costs and benefits, we recommend to consistently apply the Positive Net Benefit Differential mechanism as a starting point for negotiations on the financial closure of investments in integrated offshore infrastructure. - Highlights: • Three North Sea offshore gird case studies are analysed. • They are shown to have substantial net benefit over non-integrated network designs. • Asymmetric net benefit sharing between countries is shown to be a barrier. • Positive Net Benefit Differential method alleviates asymmetric benefits.

  2. Mapping Relative Sea Level Influences of the Cape Fear Arch in southern North Carolina

    Science.gov (United States)

    Hawkes, A.; Kemp, A.; Capar, P.

    2017-12-01

    Long-term relative sea-level (RSL) records are a necessary benchmark by which to gauge present accelerated rates of sea-level rise, future sea-level predictions, and their implications to the coastal zone. The east coast of the United States functions as a significant region of latitudinal RSL variability due to the continuous recovery of land from the deglaciation of the Laurentide Ice Sheet since the Last Glacial Maximum. Differential glacial isostatic adjustment (GIA) along the coastline has caused higher rates of subsidence in areas around the former forbulge maxima near New Jersey and Delaware and lower rates to the north and south of this maxima. However, the coast between southern North Carolina and northern South Carolina is experiencing a slower rate of RSL rise then is seen in reconstructed GIA latitudinal trends along the U.S. east coast. It was thought that this could have been attributed to non-isostatic, long-term tectonic processes causing less GIA subsidence of the lithosphere within the region impacted by uplift from the Cape Fear Arch (CFA), an underlying crystalline basement high. A recent study suggests that RSL rise is slower around the CFA than areas to the north and south due to suggested CFA uplift rates of 0.24+0.15mm a-1. An absence of RSL records for 200km north of the CFA make mapping of its influence difficult. Additional RSL records to the north of the CFA allow for a better understanding of the asymmetrical distribution in the rate of RSL rise in this region. Because the distribution in the rate of RSLR between records is not linear it is important for these low-lying coastal communities to better understand their risk to future RSLR.

  3. Marine environment protection for the North and Baltic Seas. Special Report - February 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The marine environment of the North Sea and Baltic Sea is still heavily polluted. The marine ecosystems are under severe stress from overfishing, water pollution, raw materials production and tourism. Environmental protection in this region necessitates decisive political initiatives and strict corrections especially in fishery policy, agricultural policy and chemical substances control. This is the balance of the special expert opinion of the Council of Environmental Experts. The publication specifies the main problem areas, the current pollution situation, the fields where action is most urgently required - especially in fishery, chemical substances, agricultural and sea travel policies - and presents suggestions for an integrated European and national marine protection policy including a regional development concept for the marine environment. (orig.)

  4. Decline of the North Sea houting: protective measures for an endangered anadromous fish

    DEFF Research Database (Denmark)

    Jepsen, Niels; Deacon, Michael; Koed, Anders

    2012-01-01

    Once an abundant fish species in the rivers of the Wadden Sea in northwest Europe, the North Sea houting Coregonus oxyrinchus (NSH) was at the brink of extinction 25 yr ago. The very last stronghold for this species was in the small Danish River Vidaa. In an attempt to preserve this anadromous...... whitefish species, juveniles were hatchery-reared and stocked in 6 Danish rivers flowing into the Wadden Sea. These stocking efforts were fairly successful, and the houting established populations in at least 2 of the rivers, but the underlying problem of habitat degradation and migration obstacles...... they reach sexual maturity, NSH grow relatively slowly (mean: 2.55 cm yr−1, ranging from 0 to 13.8 cm yr−1) and can reach an age of 10 to 12 yr. The number of repeated recaptures year after year indicates low mortality for adult fish. Six individuals were recaptured in rivers other than the one in which...

  5. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    OpenAIRE

    Frederikse, Thomas; Riva, R.E.M.; Slobbe, Cornelis; Broerse, D.B.T.; Verlaan, Martin

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by using a Kalman filter. The model consists of a time-varying trend and seasonal cycle, and variability induced by several physical processes, such as wind, atmospheric pressure changes and teleconne...

  6. Other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from unknown platforms in the North Atlantic Ocean, North Sea and Norwegian Sea from 1874-01-01 to 2005-12-31 (NCEI Accession 0144342)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144342 includes discrete sample and profile data collected from unknown platforms in the North Atlantic Ocean, North Sea and Norwegian Sea from...

  7. Sea surface temperature variability in the North Western Mediterranean Sea (Gulf of Lion) during the Common Era

    Science.gov (United States)

    Sicre, Marie-Alexandrine; Jalali, Bassem; Martrat, Belen; Schmidt, Sabine; Bassetti, Maria-Angela; Kallel, Nejib

    2016-12-01

    This study investigates the multidecadal-scale variability of sea surface temperatures (SSTs) in the convection region of the Gulf of Lion (NW Mediterranean Sea) over the full past 2000 yr (Common Era) using alkenone biomarkers. Our data show colder SSTs by 1.7 °C over most of the first millennium (200-800 AD) and by 1.3 °C during the Little Ice Age (LIA; 1400-1850 AD) than the 20th century mean (17.9 °C). Although on average warmer, those of the Medieval Climate Anomaly (MCA) (1000-1200 AD) were lower by 1 °C. We found a mean SST warming of 2 °C/100 yr over the last century in close agreement with the 0.22 and 0.26 °C/decade values calculated for the western Mediterranean Sea from in situ and satellite data, respectively. Our results also reveal strongly fluctuating SSTs characterized by cold extremes followed by abrupt warming during the LIA. We suggest that the coldest decades of the LIA were likely caused by prevailing negative EA states and associated anticyclone blocking over the North Atlantic resulting in cold continental northeasterly winds to blow over Western Europe and the Mediterranean region.

  8. Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

    Science.gov (United States)

    Van Engeland, T.; Soetaert, K.; Knuijt, A.; Laane, R. W. P. M.; Middelburg, J. J.

    2010-09-01

    Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robustness of the patterns against these missing data. No long-term trends in DON concentrations were found over the sampling period (1995-2005). Inter-annual variability in the different time series showed both common and station-specific behavior. The stations could be divided into two regions, based on absolute concentrations and the dominant times scales of variability. Average DON concentrations were 11 μmol l -1 in the coastal region and 5 μmol l -1 in the open sea. Organic fractions of total dissolved nitrogen (TDN) averaged 38 and 71% in the coastal zone and open sea, respectively, but increased over time due to decreasing dissolved inorganic nitrogen (DIN) concentrations. In both regions intra-annual variability dominated over inter-annual variability, but DON variation in the open sea was markedly shifted towards shorter time scales relative to coastal stations. In the coastal zone a consistent seasonal DON cycle existed with high values in spring-summer and low values in autumn-winter. In the open sea seasonality was weak. A marked shift in the seasonality was found at the Dogger Bank, with DON accumulation towards summer and low values in winter prior to 1999, and accumulation in spring and decline throughout summer after 1999. This study clearly shows that DON is a dynamic actor in the North Sea and should be monitored systematically to enable us to understand fully the functioning of this ecosystem.

  9. Stylolites, porosity, depositional texture, and silicates in chalk facies sediments:Ontong Java Plateau - Gorm and Tyra fields, North Sea

    OpenAIRE

    Fabricius, Ida Lykke; Borre, Mai K.

    2007-01-01

    Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperatu...

  10. Yellow fever

    Science.gov (United States)

    ... to thrive. Blood tests can confirm the diagnosis. Treatment There is no specific treatment for yellow fever. ... SJ, Endy TP, Rothman AL, Barrett AD. Flaviviruses (dengue, yellow fever, Japanese encephalitis, West Nile encephalitis, St. ...

  11. Inter- and intra-annual patterns of Ulva prolifera green tides in the Yellow Sea during 2007-2009, their origin and relationship to the expansion of coastal seaweed aquaculture in China.

    Science.gov (United States)

    Keesing, John K; Liu, Dongyan; Fearns, Peter; Garcia, Rodrigo

    2011-06-01

    The large green-tide events that occurred in the Yellow Sea in 2008 (3489km(2)) and 2009 (4994km(2)) are shown to be novel events preceded only once by a much smaller event in 2007 (82km(2)). The blooms originated in the coastal area of Jiangsu province and spread north-east towards the Shandong Peninsula. The blooms grew at different rates and mesoscale variability in surface winds explained the differences in the spatial and temporal patterns of blooms in 2008 and 2009. The 2009 bloom was tracked to its origin immediately offshore of extensive intertidal flats between Yancheng and Nantong where recent rapid expansion of Porphyra aquaculture has occurred. We review published hypotheses which have been advanced to explain the occurrence of blooms and in light of our findings, we conclude that the accumulation and disposal of waste Ulva prolifera from Porphyra aquaculture rafts is the most likely cause of the blooms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. 4DVAR data Assimilation with the Regional Ocean Modeling System (ROMS): Impact on the Water Mass Distributions in the Yellow Sea

    Science.gov (United States)

    Lee, Joon-Ho; Kim, Taekyun; Pang, Ig-Chan; Moon, Jae-Hong

    2018-04-01

    In this study, we evaluate the performance of the recently developed incremental strong constraint 4-dimensional variational (4DVAR) data assimilation applied to the Yellow Sea (YS) using the Regional Ocean Modeling System (ROMS). Two assimilation experiments are compared: assimilating remote-sensed sea surface temperature (SST) and both the SST and in-situ profiles measured by shipboard CTD casts into a regional ocean modeling from January to December of 2011. By comparing the two assimilation experiments against a free-run without data assimilation, we investigate how the assimilation affects the hydrographic structures in the YS. Results indicate that the SST assimilation notably improves the model behavior at the surface when compared to the nonassimilative free-run. The SST assimilation also has an impact on the subsurface water structure in the eastern YS; however, the improvement is seasonally dependent, that is, the correction becomes more effective in winter than in summer. This is due to a strong stratification in summer that prevents the assimilation of SST from affecting the subsurface temperature. A significant improvement to the subsurface temperature is made when the in-situ profiles of temperature and salinity are assimilated, forming a tongue-shaped YS bottom cold water from the YS toward the southwestern seas of Jeju Island.

  13. Exchanges between the open Black Sea and its North West shelf

    Science.gov (United States)

    Shapiro, Georgy; Wobus, Fred; Zhou, Feng

    2014-05-01

    Exchanges between the vast NW shelf and the deep basin of the Black Sea play a significant role in maintaining the balance of nutrients, heat content and salinity of the shelf waters. Nearly 87 % of the Black Sea is entirely anoxic below 70 to 200m and contains high levels of hydrogen sulphide (Zaitsev et al, 2001), and this makes the shelf waters particularly valuable for maintaining the Black Sea ecosystem in good health. The increase in salinity of shelf waters occurs partially due to exchanges with more saline open sea waters and represents a threat to relics and endemic species. The shelf-break is commonly considered the bottle-neck of the shelf-deep sea exchanges (e.g. (Huthnance, 1995, Ivanov et al, 1997). Due to conservation of potential vorticity, the geostrophic currents flow along the contours of constant depth. However the ageostrophic flows (Ekman drift, mesoscale eddies, filaments, internal waves) are not subject to the same constraints. It has been shown that during the winter well mixed cold waters formed on the North West shelf propagate into the deep sea, providing an important mechanism for the replenishment of the Cold Intermediate Layer ( Staneva and Stanev, 1997). However, much less is known about exchanges in the warm season. In this study, the transports of water, heat and salt between the northwestern shelf and the adjacent deep basin of the Black Sea are investigated using a high-resolution three-dimensional primitive equation model, NEMO-SHELF-BLS (Shapiro et al, 2013). It is shown that during the period from April to August, 2005, both onshore and offshore cross-shelf break transports in the top 20 m were as high as 0.24 Sv on average, which was equivalent to the replacement of 60% of the volume of surface shelf waters (0 - 20 m) per month. Two main exchange mechanisms are studied: (i) Ekman transport, and (ii) transport by mesoscale eddies and associated meanders of the Rim Current. The Ekman drift causes nearly uniform onshore or

  14. Yellow fever

    Directory of Open Access Journals (Sweden)

    Marcelo Nóbrega Litvoc

    Full Text Available Summary The yellow fever (YF virus is a Flavivirus, transmitted by Haemagogus, Sabethes or Aedes aegypti mosquitoes. The disease is endemic in forest areas in Africa and Latin America leading to epizootics in monkeys that constitute the reservoir of the disease. There are two forms of YF: sylvatic, transmitted accidentally when approaching the forests, and urban, which can be perpetuated by Aedes aegypti. In Brazil, the last case of urban YF occurred in 1942. Since then, there has been an expansion of transmission areas from the North and Midwest regions to the South and Southeast. In 2017, the country faced an important outbreak of the disease mainly in the states of Minas Gerais, Espírito Santo and Rio de Janeiro. In 2018, its reach extended from Minas Gerais toward São Paulo. Yellow fever has an incubation period of 3 to 6 days and sudden onset of symptoms with high fever, myalgia, headache, nausea/vomiting and increased transaminases. The disease ranges from asymptomatic to severe forms. The most serious forms occur in around 15% of those infected, with high lethality rates. These forms lead to renal, hepatic and neurological impairment, and bleeding episodes. Treatment of mild and moderate forms is symptomatic, while severe and malignant forms depend on intensive care. Prevention is achieved by administering the vaccine, which is an effective (immunogenicity at 90-98% and safe (0.4 severe events per 100,000 doses measure. In 2018, the first transplants in the world due to YF were performed. There is also an attempt to evaluate the use of active drugs against the virus in order to reduce disease severity.

  15. Insight into the Pacific Sea Surface Temperature- North American Hydroclimate Connection from an Eastern Tropical North Pacific Coral Record

    Science.gov (United States)

    Sanchez, S. C.; Charles, C. D.; Carriquiry, J. D.

    2015-12-01

    The last few years of record-breaking climate anomalies across North America--a resilient atmospheric ridge and extreme drought over the West Coast, and severe winters across the Midwest and East Coast regions--have been linked to anomalous Pacific sea surface temperatures (Seager et al. 2014, Wang et al. 2014, Hartmann 2015). The synoptic associations prompt important questions on the relation between these unusual phenomena and extreme expressions of known Pacific decadal modes, such as the North Pacific Gyre Oscillation (NPGO). These questions motivate our pursuit to document multiple realizations of decadal variability in the Pacific-North American region through periods of varied radiative forcing. Here we introduce a 178 year, seasonally resolved Porites coral record from Clarion Island (18N, 115W), the westernmost island of the Revillagigedo Archipelago, a region both highly influenced by NPGO SST and SSS variability and critical for NPGO tropical-extratropical communication via the Seasonal Footprinting Mechanism (Vimont et al. 2003). When coupled with tree ring records from the western United States (Griffin and Anchukaitis 2014, MacDonald and Case 2005) and coral records from the central tropical Pacific (Cobb et al. 2001), the δ18O signal from the Clarion coral offers an extended framework of coherent continental hydroclimate and oceanic variability across the Pacific basin beyond the instrumental record. Over the last 200 years, we find clear commonality in the timing, magnitude and spatial expression of variability (illustrated through the NADA Atlas, Cook et al. 2004) amongst the proxy records. The strong relationship between Northeastern Pacific Clarion and the Central Pacific Palmyra record with the North American hydroclimate records can be viewed within the mechanistic framework of the NPGO; this framework is then explored over the last millennium across intervals of varied radiative forcing.

  16. Yellow substance (gelbstoff)

    International Nuclear Information System (INIS)

    Medina, A.

    1988-04-01

    The different values of the mean slope (S) of the absorption coefficient a(λ) of gelbstoff (yellow substance) for each region under the same hydrological conditions and the correlation between the quantity of absorption (CA) of gelbstoff and sea water parameter is discussed. 12 refs, 6 figs, 3 tabs

  17. Human impact and environmental consequences in the North Sea and Skagerrak; Helhetlig forvaltningsplan for Nordsjoen og Skagerrak

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The expert group for the North Sea and Skagerrak has prepared six studies on human impact and environmental consequences. This is part of the technical basis for a management plan for the Norwegian part of this sea area.The expert group is requesting input on these studies from interested parties by 15 December 2011. (au)

  18. Bio-optical characterization in an ultra-oligotrophic region: the North central Red Sea

    KAUST Repository

    Kheireddine, Malika

    2015-04-01

    Until recently, satellite-derived ocean color observations have been the only means of evaluating optical variability of the Red Sea. During a cruise in autumn 2014, we investigated the variability of Inherent Optical Properties (IOPs) in the North Central Red Sea (NCRS) with a particular focus on the particulate backscattering coefficient, bbp, and colored dissolved organic matter, CDOM, absorption. To our knowledge, these are some of the measurements of these properties in the Red Sea. The IOPs are derived from the concentration and physical properties of suspended particles in the ocean. They provide a simple description of the influence of these particles on the light within the water column. Bio-optical relationships found for ultra-oligotrophic waters of the six stations sampled significantly depart from the mean standard relationships provided for the global ocean, showing the peculiar character of the Red Sea. These optical anomalies relate to the specific biological and environmental conditions occurring in the Red Sea ecosystem. Specifically, the surface specific phytoplankton absorption coefficients are lower than the values predicted from the global relationships due to a high proportion of relatively large sized phytoplankton. Conversely, bbp values are much higher than the mean standard values for a given chlorophyll-a concentration, Chl a. This presumably results from the influence of highly refractive submicrometer particles of Saharan origin in the surface layer of the water column.

  19. Contemporary radioecological state of the North-western Black Sea and the problems of environment conservation

    International Nuclear Information System (INIS)

    Tereshchenko, N.N.; Mirzoyeva, N.Yu.; Gulin, S.B.; Milchakova, N.A.

    2014-01-01

    Highlights: • Contamination of the ecosystem components by the radioactive isotopes 137 Cs, 90 Sr, 239, 240 Pu. • The maps of the temporal–spatial change in distribution of isotopes are submitted. • Zones with an increased ability to accumulate these radioactive pollutants were revealed. • Estimations of the flows of elimination of the radionuclides into the bottom sediments were carried out. • Assessment of dose rates formed by 90 Sr, 137 Cs and 239,240 Pu for Black Sea hydrobionts was obtained. - Abstract: Review is devoted to the analysis of a radioecological situation in the North-western Black Sea and concerns the levels of contamination of the components of an ecosystem by the main artificial radioactive isotopes ( 90 Sr, 137 Cs, 239,240 Pu). The long-term accumulation trends of these radionuclides were analyzed in components of the Black Sea ecosystem after the Chernobyl nuclear power plant accident. Zones that have an increased ability to accumulate these radioisotopes were revealed. The assessment of irradiation dose rates formed by 90 Sr, 137 Cs and 239,240 Pu in Black Sea hydrobionts was obtained. The strategy for biodiversity conservation and sustainable management of natural resources should include monitoring of the radioecological state of the marine ecosystems, and the formation of a complex of biogeochemical criteria for assessment of an ecological situation in the sea. This approach is important for marine protected areas, since it allows the formation of a basis for scientific and practical function

  20. Haplosporidium nelsoni (MSX) in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China.

    Science.gov (United States)

    Wang, Zhongwei; Lu, Xin; Liang, Yubo

    2012-04-01

    The protozoan parasite Haplosporidium nelsoni (MSX) was identified in Japanese scallops Patinopecten yessoensis (Jay, 1857) from Dalian along the northern coast of the Yellow Sea, China by histopathologic examination, polymerase chain reaction (PCR) amplification, and in situ hybridization (ISH) assay. H. nelsoni plasmodia-like structures were identified in the digestive glands of scallops by histologic examination, but no parasite spores were observed. PCR using the Hap-F2, R2 primer pair produced a sequence with 100% homology with the corresponding small subunit rDNA region of H. nelsoni. An ISH assay using the oligonucleotide probe MSX1347 produced a positive reaction with the Japanese scallop parasite. This is the first report of H. nelsoni in P. yessoensis in China.

  1. Bohai and Yellow Sea Oil Spill Prediction System and Its Application to Huangdao ‘11.22’ Oil Spill Incident

    Science.gov (United States)

    Li, Huan; Li, Yan; Li, Cheng; Li, Wenshan; Wang, Guosong; Zhang, Song

    2017-08-01

    Marine oil spill has deep negative effect on both marine ecosystem and human activities. In recent years, due to China’s high-speed economic development, the demand for crude oil is increasing year by year in China, and leading to the high risk of marine oil spill. Therefore, it is necessary that promoting emergency response on marine oil spill in China and improving oil spill prediction techniques. In this study, based on oil spill model and GIS platform, we have developed the Bohai and Yellow sea oil spill prediction system. Combining with high-resolution meteorological and oceanographic forecast results, the system was applied to predict the drift and diffusion process of Huangdao ‘11.22’ oil spill incident. Although the prediction can’t be validated by some SAR images due to the lack of satellite observations, it still provided effective and referable oil spill behavior information to Maritime Safety Administration.

  2. Environmental impact of sea bass cage farming in the north Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Domenico Lanari

    2010-01-01

    Full Text Available The main objective of the research was to reduce the organic and nutrient load under the net pen fish farms. An exper- iment was conducted to study the effects of artificial barriers fixed under a set of sea cages in order to reduce the envi- ronmental impact. The artificial barriers were made of four submerged galvanized steel pipes coated with plastic and placed on the sea floor (10 m depth in the Trieste gulf. The experimental design was as follows: control (C, cages with barriers (B, cages without barriers (WB. Measurements were taken on the surface as well as at 4 and 8m of depth. The trial lasted from the end of June 2000 to December 2001. Water quality parameters were not significantly influenced by the fish cages. Surface samples were characterised by lower levels of salinity and higher levels of oxygen and nitrate compared to those taken at 4 and 8 m. The artificial barriers favoured the establishment of a rich epiphytic fauna that took advantage of the presence of organic matter derived from fish cages. The two species Nucula nucleusand Neanthes caudataand the total bacterial counts were identified as potential indicators of pollution under the fish cage farms.

  3. Low-frequency variability in North Sea and Baltic Sea identified through simulations with the 3-D coupled physical–biogeochemical model ECOSMO

    Directory of Open Access Journals (Sweden)

    U. Daewel

    2017-09-01

    Full Text Available Here we present results from a long-term model simulation of the 3-D coupled ecosystem model ECOSMO II for a North Sea and Baltic Sea set-up. The model allows both multi-decadal hindcast simulation of the marine system and specific process studies under controlled environmental conditions. Model results have been analysed with respect to long-term multi-decadal variability in both physical and biological parameters with the help of empirical orthogonal function (EOF analysis. The analysis of a 61-year (1948–2008 hindcast reveals a quasi-decadal variation in salinity, temperature and current fields in the North Sea in addition to singular events of major changes during restricted time frames. These changes in hydrodynamic variables were found to be associated with changes in ecosystem productivity that are temporally aligned with the timing of reported regime shifts in the areas. Our results clearly indicate that for analysing ecosystem productivity, spatially explicit methods are indispensable. Especially in the North Sea, a correlation analysis between atmospheric forcing and primary production (PP reveals significant correlations between PP and the North Atlantic Oscillation (NAO and wind forcing for the central part of the region, while the Atlantic Multi-decadal Oscillation (AMO and air temperature are correlated to long-term changes in PP in the southern North Sea frontal areas. Since correlations cannot serve to identify causal relationship, we performed scenario model runs perturbing the temporal variability in forcing condition to emphasize specifically the role of solar radiation, wind and eutrophication. The results revealed that, although all parameters are relevant for the magnitude of PP in the North Sea and Baltic Sea, the dominant impact on long-term variability and major shifts in ecosystem productivity was introduced by modulations of the wind fields.

  4. Bathymetric controls on Pliocene North Atlantic and Arctic sea surface temperature and deepwater production

    Science.gov (United States)

    Robinson, M.M.; Valdes, P.J.; Haywood, A.M.; Dowsett, H.J.; Hill, D.J.; Jones, S.M.

    2011-01-01

    The mid-Pliocene warm period (MPWP; ~. 3.3 to 3.0. Ma) is the most recent interval in Earth's history in which global temperatures reached and remained at levels similar to those projected for the near future. The distribution of global warmth, however, was different than today in that the high latitudes warmed more than the tropics. Multiple temperature proxies indicate significant sea surface warming in the North Atlantic and Arctic Oceans during the MPWP, but predictions from a fully coupled ocean-atmosphere model (HadCM3) have so far been unable to fully predict the large scale of sea surface warming in the high latitudes. If climate proxies accurately represent Pliocene conditions, and if no weakness exists in the physics of the model, then model boundary conditions may be in error. Here we alter a single boundary condition (bathymetry) to examine if Pliocene high latitude warming was aided by an increase in poleward heat transport due to changes in the subsidence of North Atlantic Ocean ridges. We find an increase in both Arctic sea surface temperature and deepwater production in model experiments that incorporate a deepened Greenland-Scotland Ridge. These results offer both a mechanism for the warming in the North Atlantic and Arctic Oceans indicated by numerous proxies and an explanation for the apparent disparity between proxy data and model simulations of Pliocene northern North Atlantic and Arctic Ocean conditions. Determining the causes of Pliocene warmth remains critical to fully understanding comparisons of the Pliocene warm period to possible future climate change scenarios. ?? 2011.

  5. Biogeochemical consequences of vertical and lateral transport of particulate organic matter in the southern North Sea: A multiproxy approach

    NARCIS (Netherlands)

    Le Guitton, M.; Soetaert, K.; Sinninghe Damsté, J.S.; Middelburg, J.J.

    2015-01-01

    Vertical and lateral transports are of importance in continental shelf systems such as the North Sea andplay a major role in the processing of organic matter. We investigated the biogeochemical consequencesof these transports on particulate organic matter at the molecular level in the southern North

  6. Trophodynamics and functional feeding groups of North Sea fauna: a combined stable isotope and fatty acid approach

    NARCIS (Netherlands)

    Kürten, B.; Frutos, I.; Struck, U.; Painting, S.J.; Polunin, N.V.C.; Middelburg, J.J.

    The trophodynamics of pelagic and benthic animals of the North Sea, North Atlantic shelf, were assessed using stable isotope analysis (SIA) of natural abundance carbon and nitrogen isotopes, lipid fingerprinting and compound-specific SIA (CSIA) of phospholipid-derived fatty acids (PLFAs).

  7. Trophodynamics and functional feeding groups of North Sea fauna: a combined stable isotope and fatty acid approach

    NARCIS (Netherlands)

    Kürten, B.; Frutos, I.; Struck, U.; Painting, S.J.; Polunin, N.V.C.; Middelburg, J.J.

    2013-01-01

    The trophodynamics of pelagic and benthic animals of the North Sea, North Atlantic shelf, were assessed using stable isotope analysis (SIA) of natural abundance carbon and nitrogen isotopes, lipid fingerprinting and compound-specific SIA (CSIA) of phospholipid-derived fatty acids (PLFAs).

  8. TOPAZ4: an ocean-sea ice data assimilation system for the North Atlantic and Arctic

    Directory of Open Access Journals (Sweden)

    P. Sakov

    2012-08-01

    Full Text Available We present a detailed description of TOPAZ4, the latest version of TOPAZ – a coupled ocean-sea ice data assimilation system for the North Atlantic Ocean and Arctic. It is the only operational, large-scale ocean data assimilation system that uses the ensemble Kalman filter. This means that TOPAZ features a time-evolving, state-dependent estimate of the state error covariance. Based on results from the pilot MyOcean reanalysis for 2003–2008, we demonstrate that TOPAZ4 produces a realistic estimate of the ocean circulation in the North Atlantic and the sea-ice variability in the Arctic. We find that the ensemble spread for temperature and sea-level remains fairly constant throughout the reanalysis demonstrating that the data assimilation system is robust to ensemble collapse. Moreover, the ensemble spread for ice concentration is well correlated with the actual errors. This indicates that the ensemble statistics provide reliable state-dependent error estimates – a feature that is unique to ensemble-based data assimilation systems. We demonstrate that the quality of the reanalysis changes when different sea surface temperature products are assimilated, or when in-situ profiles below the ice in the Arctic Ocean are assimilated. We find that data assimilation improves the match to independent observations compared to a free model. Improvements are particularly noticeable for ice thickness, salinity in the Arctic, and temperature in the Fram Strait, but not for transport estimates or underwater temperature. At the same time, the pilot reanalysis has revealed several flaws in the system that have degraded its performance. Finally, we show that a simple bias estimation scheme can effectively detect the seasonal or constant bias in temperature and sea-level.

  9. 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 G.O. SARS in the North Greenland Sea, North Sea and Norwegian Sea from 2011-04-29 to 2011-11-01 (NCEI Accession 0157278)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157278 includes Surface underway, chemical, meteorological and physical data collected from G.O. SARS in the North Greenland Sea, North Sea and...

  10. Observations on a population of the sea anemone Anemonia viridis (Forskal, 1775) in the North Aegean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Chariton Chintiroglou, C. [Thessaloniki, Aristotle Univ. (Greece). Dept. of Zoology

    1996-12-31

    The present paper is concerned with the structural aspects of Anemonia viridis populations found in the North Aegean Sea. It was found that mean wet weight and density of anemone populations increases with depth and distance from shore. Differences in the structure of the Anemonia viridis populations were attributed both to the specific hydrodynamic characteristics of the biotopes and to a number biotic interactions. From our results and t previous investigations the adoption of three different lifestyles by the anemones was assumed.: (1) a colonial form, with population densities around 650 individuals per m{sup 2}, found in substrates exposed to increased hydrodynamism; (2) a colonial form, with lower densities (90 indiv. per m{sup 2}), found in less exposed sites; (3) finally, large individuals in deeper waters chose a solitary lifestyle, as mechanical stresses were much lower.

  11. Causes of accelerating sea level on the East Coast of North America.

    Science.gov (United States)

    Davis, James L; Vinogradova, Nadya T

    2017-05-28

    The tide-gauge record from the North American East Coast reveals significant accelerations in sea level starting in the late twentieth century. The estimated post-1990 accelerations range from near zero to ∼0.3 mm yr -2 . We find that the observed sea level acceleration is well modeled using several processes: mass change in Greenland and Antarctica as measured by the Gravity Recovery and Climate Experiment satellites; ocean dynamic and steric variability provided by the GECCO2 ocean synthesis; and the inverted barometer effect. However, to achieve this fit requires estimation of an admittance for the dynamical and steric contribution, possibly due to the coarse resolution of this analysis or to simplifications associated with parameterization of bottom friction in the shallow coastal areas. The acceleration from ice loss alone is equivalent to a regional sea level rise in one century of 0.2 m in the north and 0.75 m in the south of this region.

  12. Coastal Sea Level along the North Eastern Atlantic Shelf from Delay Doppler Altimetry

    Science.gov (United States)

    Fenoglio-Marc, L.; Benveniste, J.; Andersen, O. B.; Gravelle, M.; Dinardo, S.; Uebbing, B.; Scharroo, R.; Kusche, J.; Kern, M.; Buchhaupt, C.

    2017-12-01

    Satellite altimetry data of the CryoSat-2 and Sentinel-3 missions processed with Delay Doppler methodology (DDA) provide improved coastal sea level measurements up to 2-4 km from coast, thanks to an along-track resolution of about 300m and a higher signal to noise ratio. We investigate the 10 Kilometre stripe along the North-Eastern Atlantic shelf from Lisbon to Bergen to detect the possible impacts in sea level change studies of this enhanced dataset. We consider SAR CryoSat-2 and Sentinel-3 altimetry products from the ESA GPOD processor and in-house reduced SAR altimetry (RDSAR) products. Improved processing includes in RDSAR the application of enhanced retrackers for the RDSAR waveform. Improved processing in SAR includes modification both in the generation of SAR waveforms, (as Hamming weighting window on the burst data prior to the azimuth FFT, zero-padding prior to the range FFT, doubling of the extension for the radar range swath) and in the SAMOSA2 retracker. Data cover the full lifetime of CryoSat-2 (6 years) and Sentinel-3 (1 year). Conventional altimetry are from the sea level CCI database. First we analyse the impact of these SAR altimeter data on the sea level trend and on the estimation of vertical motion from the altimeter minus tide gauge differences. VLM along the North-Eastern Atlantic shelf is generally small compared to the North-Western Atlantic Coast VLM, with a smaller signal to noise ratio. Second we investigate impact on the coastal mean sea level surface and the mean dynamic topography. We evaluate a mean surface from the new altimeter data to be combined to state of the art geoid models to derive the mean dynamic topography. We compare the results to existing oceanographic and geodetic mean dynamic topography solutions, both on grid and pointwise at the tide gauge stations. This study is supported by ESA through the Sea Level CCI and the GOCE++DYCOT projects

  13. The caesium 137 content in the water of the North Sea during the years 1969 to 1975

    International Nuclear Information System (INIS)

    Kautsky, H.

    1976-01-01

    In April 1975, about 34,000 Ci Caesium 137 in a water mass of about 30,500 km 3 was found in the area of the North Sea that we investigated between 51 0 N to 60 0 N and 4 0 W to 10 0 E. This represented a mean concentration of about 1.1 Ci/km 3 or 1.1 pCi/l water. Concentration variations of between 0.44 to 2.2 pCi/l in the different areas of the North Sea were measured. As compared with ICRP Standards, 137 Cs concentrations in sea water of up to some 900 pCi/l may be viewed as a still permissible limit (IAEA, 1970). The development of the 137 Cs content in the North Sea from 1969 to 1975 is discussed. Especially, the temporal changes in concentrations in different sections of the North Sea will be compared. These clearly show the different influence in different sections of the radioactive waste waters of the three coastal European nuclear fuel reprocessing plants on the content of radioactive fission products as well as their spreading in the water of the North Sea. (orig./HP) [de

  14. Mechanisms controlling the intra-annual mesoscale variability of SST and SPM in the southern North Sea

    Science.gov (United States)

    Pietrzak, Julie D.; de Boer, Gerben J.; Eleveld, Marieke A.

    2011-04-01

    Thermal and optical remote sensing data were used to investigate the spatial and temporal distribution of sea surface temperature (SST) and of suspended particulate matter (SPM) in the southern North Sea. Monthly SST composites showed pronounced seasonal warming of the southern North Sea and delineated the English coastal and continental coastal waters. The East-Anglia Plume is the dominant feature of the English coastal waters in the winter and autumn SPM composites, and the Rhine region of freshwater influence (ROFI), including the Flemish Banks, is the dominant feature of the continental waters. These mesoscale spatial structures are also influenced by the evolution of fronts, such as the seasonal front separating well-mixed water in the southern Bight, from the seasonally stratified central North Sea waters. A harmonic analysis of the SST and SPM images showed pronounced seasonal variability, as well as spring-neap variations in the level of tidal mixing in the East Anglia Plume, the Rhine ROFI and central North Sea. The harmonic analysis indicates the important role played by the local meteorology and tides in governing the SST and near-surface SPM concentrations in the southern North Sea. In the summer, thermal stratification affects the visibility of SPM to satellite sensors in the waters to the north of the Flamborough and Frisian Fronts. Haline stratification plays an important role in the visibility of SPM in the Rhine ROFI throughout the year. When stratified, both regions typically exhibit low surface SPM values. A numerical model study, together with the harmonic analysis, highlights the importance of tides and waves in controlling the stratification in the southern North Sea and hence the visibility of SPM.

  15. The influence of riverine nitrogen on the dynamics of the North Sea oxygen minimum zone

    Science.gov (United States)

    Große, Fabian; Kreus, Markus; Lenhart, Hermann; Pätsch, Johannes

    2016-04-01

    The mitigation of eutrophication and its concomitants, like oxygen deficiency in bottom waters, is one of the major aspects of the ecological management of coastal marine ecosystems. In the past, biogeochemical models helped to significantly improve the understanding of the interaction of the physical and biological processes driving eutrophication. Anthropogenic river input of nitrogen (N) and phosphorus (P) is the main driver for eutrophication. Nevertheless, the quantification of their influence in a specific region remains an important issue, since it is as crucial for an efficient management as it is difficult to obtain. During the past decade, a quantitative method applicable to biogeochemical models - often referred to as `trans-boundary nutrient transports' (TBNT) - became more and more popular in the context of marine ecosystem management. This method allows for the tracing of elements from various sources, e.g., nitrogen (N) from different rivers, throughout the whole process chain of the applied model. By this, it provides valuable information about the contributions from different sources to the overall amount and turnover of an element in different areas of the model domain. This information constitutes the basis for the quantification, evaluation and optimisation of river input reduction targets for the tributaries, which are defined in relation to their ecological consequences in the marine environment. In existing studies, the TBNT method has been applied to a variety of biogeochemical models, e.g. to quantify the atmospheric contribution to total N in the North Sea (Troost et al., 2013). This study presents a novel approach to link the TBNT method applied to N to the biological processes driving the oxygen dynamics in the bottom layer of the North Sea. For this purpose, simulations from the biogeochemical model ECOHAM (ECOlogical model HAMburg) are analysed for the years 2002 and 2010, with the focus on the southern central North Sea, the region of

  16. Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

    Science.gov (United States)

    Sasakawa, Motoki; Uematsu, Mitsuo

    2002-12-01

    Samples of aerosol, sea fog, and rainwater were collected during a research cruise in the northwestern North Pacific, the Sea of Okhotsk, and the Sea of Japan in the summer of 1998. High concentrations of NO3-, nss-SO42- and NH4+ in aerosol over the Sea of Japan suggest that anthropogenic substances were transported to this region. Although the Sea of Okhotsk was covered with a clean marine air mass, the concentration of nss-SO42- was comparatively high in the aerosol samples. This nss-SO42- is probably of marine biogenic origin. The pH values of fogwater samples were measured to be fogwater collected over the Sea of Japan were higher than those in the other regions, suggesting that the sea fog scavenged anthropogenic substances. The concentration of nss-SO42- in fogwater over the Sea of Okhotsk was equivalent to that over the Sea of Japan, probably because nss-SO42- and SO2 of marine biogenic origin were scavenged by the sea fog over the Sea of Okhotsk. The pH values of rainwater samples ranged from 6.1 to 7.2 during the cruise, and acidification of the rain was not significant. The concentrations of nss-Ca2+ in the rainwater were higher than those of the fogwater. This suggests that the rain-scavenged continental CaCO3 may have existed above the lower marine boundary layer, where sea fog appeared. Comparisons of the composition of aerosol and fogwater indicated that coarse particles, such as sea salts predominantly act as condensation nuclei of sea fog droplets rather than fine particles such as (NH4)2SO4.

  17. A model for tides and currents in the English Channel and southern North Sea

    Science.gov (United States)

    Walters, Roy. A.

    The amplitude and phase of 11 tidal constituents for the English Channel and southern North Sea are calculated using a frequency domain, finite element model. The governing equations — the shallow water equations — are modifed such that sea level is calculated using an elliptic equation of the Helmholz type followed by a back-calculation of velocity using the primitive momentum equations. Triangular elements with linear basis functions are used. The modified form of the governing equations provides stable solutions with little numerical noise. In this field-scale test problem, the model was able to produce the details of the structure of 11 tidal constituents including O 1, K 1, M 2, S 2, N 2, K 2, M 4, MS 4, MN 4, M 6, and 2MS 6.

  18. Wettability Improvement with Enzymes: Application to Enhanced Oil Recovery under Conditions of the North Sea Reservoirs

    DEFF Research Database (Denmark)

    Khusainova, Alsu; Shapiro, Alexander; Stenby, Erling Halfdan

    2012-01-01

    (Nasiri et al., 2009), working mechanisms are poorly known and understood. The main goal of the present work is to establish possible mechanisms in which enzymes may enhance oil recovery. Improvement of the brine wettability of the rock and decrease of oil adhesion to it by addition of an enzyme is one...... of the possible mechanisms of enzymatic action. This mechanism has been investigated experimentally, by measurements of the contact angles between oil drops and enzyme solutions in brine on the mineral surfaces. Fifteen enzyme samples belonging to different enzyme classes, such as esterases/lipases, carbohydrases......, proteases and oxidoreductases, provided by Novozymes, have been investigated. Two commercial mixtures containing enzymes: Apollo-GreenZyme™ and EOR-ZYMAX™ have also been applied. The North Sea dead oil and the synthetic sea water were used as test fluids. Internal surface of a carbonate rock has been...

  19. Sulfate-Reducing Prokaryotes from North Sea Oil reservoirs; organisms, distribution and origin

    Energy Technology Data Exchange (ETDEWEB)

    Beeder, Janiche

    1996-12-31

    During oil production in the North Sea, anaerobic seawater is pumped in which stimulates the growth of sulphate-reducing prokaryotes that produce hydrogen sulphide. This sulphide causes major health hazards, economical and operational problems. As told in this thesis, several strains of sulphate reducers have been isolated from North Sea oil field waters. Antibodies have been produced against these strains and used to investigate the distribution of sulphate reducers in a North Sea oil reservoir. The result showed a high diversity among sulphate reducers, with different strains belonging to different parts of the reservoir. Some of these strains have been further characterized. The physiological and phylogenetic characterization showed that strain 7324 was an archaean. Strain A8444 was a bacterium, representing a new species of a new genus. A benzoate degrading sulphate reducing bacterium was isolated from injection water, and later the same strain was detected in produced water. This is the first field observations indicating that sulphate reducers are able to penetrate an oil reservoir. It was found that the oil reservoir contains a diverse population of thermophilic sulphate reducers able to grow on carbon sources in the oil reservoir, and to live and grow in this extreme environment of high temperature and pressure. The mesophilic sulphate reducers are established in the injection water system and in the reservoir near the injection well during oil production. The thermophilic sulphate reducers are able to grow in the reservoir prior to, as well as during production. It appears that the oil reservoir is a natural habitat for thermophilic sulphate reducers and that they have been present in the reservoir long before production started. 322 refs., 9 figs., 11 tabs.

  20. Developmental defects in pelagic embryos of several flatfish species in the Southern North sea

    Science.gov (United States)

    Cameron, P.; Berg, J.; Dethlefsen, V.; Von Westernhagen, H.

    In the spring of 1984 through and in the summer of 1987 pelagic flatfish eggs were collected in horizontal subsurface hauls with a 1-m ring net in the southern North Sea between 51°49' to 55°30'N and 2°30' to 8°00'E. The flatfish eggs were observed alive for their developmental stage and aberrations from normal development. Flatfish eggs occurring in the winter ichthyoplankton of the southern North Sea were dab, Limanda limanda; flounder. Platichthys flesus; plaice, Pleuronectes platessa, and long rough dab, Hippoglossoides platessoides. Summer samples contained dab, turbot, Psetta maxima; little sole, Buglossidium luteum; common sole, Solea solea; Norwegian topknot, Phrynorhombus norwegicus, and lemon sole, Microstomus kitt. In winter as well as in summer eggs of dab were the most abundant in the southern North Sea with up to 249 eggs·m -3 surface water in winter and 26 eggs·m -3 in summer. The investigations revealed considerable quantities of abnormally developed flatfish embryos in the plankton samples. Highest malformation rates were recorded for the early stages of dab (44.4%) followed by flounder (41.3%) and plaice (26.0%) in winter; in summer these rates were for dab 18.9%, for turbot 14.1% and for little sole 12.5%. Generally malformation rates decreased with development. Areas of high malformation rates were off the river estuaries and in near-shore areas along the Dutch and German coasts. Malformation rates decreased with the distance from the coast. Causes and effects of the occurrence of malformations during embryonic development are discussed.