WorldWideScience

Sample records for bottom substrate sea

  1. Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Data report 2001

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2002-08-15

    The Ministry of Environment and Energy requested ELSAM and ELTRA to establish an offshore wind farm with an output of 150 MW in the waters of Horns Rev, approximately 15 km off Blaevandshuk, which is the most westerly point of Denmark. The first phase of construction of the wind farm have started in spring 2002. Before the construction activities take place, a baseline description of the benthos has been conducted as a part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines for offshore wind farms prepared by the Danish Energy Agency. The monitoring programme established for the benthic infauna was performed in spring 2001. In addition to a proposed fish investigation programme concerning the stomach contents of fish a comparative programme on benthos was established as part of the monitoring programme. The benthos sampling in connection with the fish programme was conducted in autumn 2001. This benthic survey includes sampling in a proposed reference area for the fish surveys north east of the wind farm. This report presents the data of the baseline environmental survey of the seabed in the wind farm site and in the proposed reference site and a brief description of the weather conditions at the time of sampling. (au)

  2. Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Data report 2001

    International Nuclear Information System (INIS)

    The Ministry of Environment and Energy requested ELSAM and ELTRA to establish an offshore wind farm with an output of 150 MW in the waters of Horns Rev, approximately 15 km off Blaevandshuk, which is the most westerly point of Denmark. The first phase of construction of the wind farm have started in spring 2002. Before the construction activities take place, a baseline description of the benthos has been conducted as a part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines for offshore wind farms prepared by the Danish Energy Agency. The monitoring programme established for the benthic infauna was performed in spring 2001. In addition to a proposed fish investigation programme concerning the stomach contents of fish a comparative programme on benthos was established as part of the monitoring programme. The benthos sampling in connection with the fish programme was conducted in autumn 2001. This benthic survey includes sampling in a proposed reference area for the fish surveys north east of the wind farm. This report presents the data of the baseline environmental survey of the seabed in the wind farm site and in the proposed reference site and a brief description of the weather conditions at the time of sampling. (au)

  3. Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Status report 2001

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2002-08-15

    A baseline description of the benthos was carried out in spring and autumn 2001 prior to the construction of an offshore wind farm at Horns Rev, situated approximately 15 km off Blaevands Huk, which is Denmark's most westerly point. The surveys have been conducted as part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines set up by the Danish Energy Agency for offshore wind farms. Because no environmental criteria existed for benthic communities in connection with the construction activities, no power analysis was made prior to the design of the monitoring programme. The monitoring programme established for the benthic infauna is thus somewhat limited and only major changes in the community structure are expected to be detectable. The baseline description for the benthic infauna can also be used for comparison of the stomach contents of fish in a comparative programme. A newly defined reference area may be introduced for the fish programme why sampling in this area was carried out in the autumn 2001. Samples were recovered at a total of 18 stations at 6 wind turbine locations in the wind farm area in June 2001 and at a total of 9 stations at 3 wind turbine locations in September 2001. In September additional sampling was carried out at 5 stations in a designated reference area. At the wind turbine locations sampling was carried out at 3 stations located 5, 25 and 100 m from the edge of the planned scour protection. Samples were analysed for sediment characteristics and for benthic infauna. Only the benthos relating to the macrofauna was investigated during the surveys. (au)

  4. Time variable bottom water outflow in the Northwestern Weddell Sea

    Science.gov (United States)

    Kanzow, Torsten; Rohardt, Gerd

    2015-04-01

    The Antarctic Bottom Water (AABW) has shown widespread warming in recent decades, with implications for sea level rise and global heat uptake. Anomalously warm AABW has recently been reported to have reached the Brazil basin in the South Atlantic, while the warming further south partly seems to have come to a halt. The Weddell Sea represents the primary source of Antarctic Bottom Water (AABW) formation in the Southern Ocean. More than 60% of the AABW are supplied by Weddell Sea Deep Water, of which Weddell Sea Bottom Water (WSBW) is the main source. WSBW descends down the continental slope along the western margin of the Weddell Sea as a northward flowing plume, thereby entraining warmer ambient waters. The plume has been observed using moored current meters and temperature sensors between 1989 and 1998 and between 2005 and 2012 near the tip of the Antarctic Peninsula, complemented by repeated cross-slope CTD sections along the mooring array. In this study we extend the WSBW volume transport and temperature time series of Fahrbach et al. (2001) originally covering the 1989-1998 interval by the more recent period. We will report on both seasonal to inter-annual variability and possible longer-term trends in both volume transport and temperature of WSBW. The results will be discussed in the context of changes in the source areas of WSBW, such as the breakup of parts of the Larsen Ice Shelf on the eastern Arctic Peninsula, possibly fueling the formation dense water on the shelf.

  5. Hard bottom substrate monitoring Horns Rev offshore wind farm. Annual status report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2004-05-15

    Elsam and Eltra built the offshore demonstration wind farm at Horns Rev in the North Sea. Elsam is the owner and is responsible for the operation of the wind farm. Eltra is responsible for the connection of the wind farm to the national onshore grid. In the summer months of 2002, Elsam constructed the world's largest offshore wind farm off the Danish west coast. The wind farm is sited 14-20 km into the North Sea, west of Blaevands Huk. The first wind turbine was erected in May 2002 and the last wind turbine tower of a total of 80 was in place by August 2002. The construction work was completed with the last connecting cables sluiced down in September 2002. All the wind turbines were in production by December 2002. The expected impact of the wind farm will primarily be an alternation of habitats due to the introduction of hard bottom substrates as wind turbine towers and scour protections. A continuous development in the epifouling communities will be expected together with an introduction of new or alien species in the area. The indigenous benthic community in the area of Horns Rev can be characterised by infauna species belonging to the Goniadella-Spisula community. This community is typical of sandbanks in the North Sea area, although communities in such areas are very variable and site-specific. Character species used as indicators for environmental changes in the Horns Rev area are the bristle worms Goniadella bobretzkii, Ophelia borealis, Psione remota and Orbinia sertulata and the mussels Goodallia triangularis and Spisula solida. In connection with the implementation of the monitoring programme concerning the ecological impact of the introduction of hard substrate related to the Horns Rev Wind Farm, surveys on hard bottom substrate was conducted in March 2003 and in September 2003. This report describes the first year results of surveys on hard substrate after the completion of the offshore wind farm at Horns Rev. (au)

  6. Hard bottom substrate monitoring Horns Rev offshore wind farm. Annual status report. 2004

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2005-05-15

    Elsam and Eltra have built the offshore demonstration wind farm at Horns Rev in the North Sea. Elsam is the owner and is responsible for the operation of the wind farm. Eltra is responsible for the connection of the wind farm to the national onshore grid. In the summer months of 2002, Elsam constructed the world's largest offshore wind farm at the Danish west coast. The wind farm is located 14-20 km into the North Sea, west of Blaevands Huk. The first wind turbine foundation was in place in March 2002 and the last mono-pile was in place in August 2002 for a total of 80. The construction work was completed with the last connecting cables sluiced down in September 2002. All the wind turbines were in production in December 2002. The expected impact from the wind farm will primarily be an alternation of habitats due to the introduction of hard bottom substrates as wind mono-piles and scour protections. A continuous development in the epifouling communities will be expected together with an introduction of new or alien species in the area. The indigenous benthic community in the area of Horn Rev can be characterised by infauna species belonging to the Goniadella-Spisula community. This community is typical of sandbanks in the North Sea area, although communities in such areas are very variable and site specific. Character species used as indicators for environmental changes in the Horns Rev area are the bristle worms Goniadella bobretzkii, Ophelia borealis, Psione remota and Orbinia sertulata and the mussels Goodallia triangularis and Spisula solida. In connection with the implementation of the monitoring programme concerning the ecological impact of the introduction of hard substrate related to the Horns Rev Wind Farm, surveys on hard bottom substrates were initialised in March 2003 with monitoring conducted in September 2003 and March and September 2004. This report describes the results from surveys on hard substrates in 2004. (au)

  7. Heat flow through the sea bottom around the Yucatan Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Khutorskoy, M.D.; Kononov, V.I.; Polyak, B.G. (Geological Inst., Moscow (USSR)); Fernandez, R. (Centro de Investigacion Cientifica y Educacion Superior de Ensenada, Baja California (Mexico)); Matveev, V.G.; Rot, A.A. (Polytechnical Inst., Kuybyshev (USSR))

    1990-02-10

    Heat flow studies were conducted in January-February 1987, off the Atlantic Coast of Mexico on board the R/V Akademik Nikolai Strakhov. Two areas were surveyed, one transecting the Salt Dome Province and the Campeche Canyon, in the Gulf of Mexico, and the other, on the eastern flank of the Yucatan Peninsula. Conductive heat flow through the bottom sediments was determined as the product of vertical temperature gradient and in situ thermal conductivity, measured with a thermal probe using a multithermistor array and real-time processing capabilities. Forward two-dimensional modeling allows one to estimate heat flow variations at both sites from local disturbances and to obtain average heat flow values of 51 mW/m{sup 2} for the transect within the Gulf of Mexico and 38 and 69 mW/m{sup 2} for two basins within the Yucatan area. Sea bottom relief has a predominant effect over other environmental factors in the scatter of heat flow determination in the Gulf of Mexico.

  8. Water purification with sintered porous materials fabricated at 400℃ from sea bottom sediments

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A sintering technology for preparing porous materials from sea bottom sediments was developed for use in water purification. The purpose of the present study was to develop methods for converting the sea bottom sediments dredged from Ago Bay into value-added recycled products. The sintered products fabricated at 400℃ were found to be very effective adsorbents for the removal of heavy metals.

  9. Measurements by Ocean Bottom Gravimeter at Harima-nada in Seto Inland Sea, Japan

    Science.gov (United States)

    Joshima, Masato; Ishihara, Takemi; Koizumi, Kin-Ichiro; Seama, Nobukazu; Oshida, Atsushi; Fujimoto, Hiromi; Kanazawa, Toshihiko

    Gravity measurements on the sea bottom using an ocean bottom gravimeter(OBG) and a small survey vessel of 8.5 tons were performed at Harima-nada, in the Seto Inland Sea, Japan. Measurements at one bottom station were completed in about 30 minutes including 2 mile transit from the previous station, and 23 new data were obtained during 4 days. The measurement noise on the shallow sea-bottom was reduced considerably by attaching an anchor to the rope between the deployed ocean bottom gravimeter and the ship, and by keeping the ship almost fixed to the deployed anchor. The measurement accuracy is better than 0.005 mgal at the base station and is better than 0.05 mgal for the sea bottom measurements with the anchor. The new measurements combined with old data revealed the presence of high gravity anomaly zone running in Harima-nada sub-parallel to the Median Tectonic Line.

  10. Analysis of hydrodynamic characteristics of unmanned underwater vehicle moving close to the sea bottom

    Directory of Open Access Journals (Sweden)

    Xiao-xu Du

    2014-03-01

    Full Text Available The accurate research on the hydrodynamics of unmanned underwater vehicle (UUV, which moves close to the sea bottom, has a great significance for its maneuverability. The structured grid of the computational models with different distances to the sea bottom and attack angles is generated by Ansys ICEM, and the flow field near the sea bottom is simulated using CFX. The characteristics of the drag, lift, pitching moment influenced by the distance to sea bottom and the attack angle are studied. The result shows that the drag coefficient increases with the decrease of distance, while it increases with the increase of attack angle. There exists attraction force when UUV moves close to the sea bottom, and the attraction force increases with the decrease in distance. The lift coefficient increases with the increase in attack angle. The absolute value of the pitching moment coefficient increases with the decrease in distance and the increase in attack angle.

  11. Analysis of hydrodynamic characteristics of unmanned underwater vehicle moving close to the sea bottom

    Institute of Scientific and Technical Information of China (English)

    Xiao-xu DU; Huan WANG; Cheng-zhi HAO; Xin-liang LI

    2014-01-01

    The accurate research on the hydrodynamics of unmanned underwater vehicle (UUV), which moves close to the sea bottom, has a great significance for its maneuverability. The structured grid of the computational models with different distances to the sea bottom and attack angles is generated by Ansys ICEM, and the flow field near the sea bottom is simulated using CFX. The characteristics of the drag, lift, pitching moment influenced by the distance to sea bottom and the attack angle are studied. The result shows that the drag coefficient increases with the decrease of distance, while it increases with the increase of attack angle. There exists attraction force when UUV moves close to the sea bottom, and the attraction force increases with the decrease in distance. The lift coefficient increases with the increase in attack angle. The absolute value of the pitching moment coefficient increases with the decrease in distance and the increase in attack angle.

  12. Preliminary Hard and Soft Bottom Seafloor Substrate Map Derived from an Unsupervised Classification of Gridded Backscatter and Bathymetry Derivatives at Selected U.S. Locations in the Pacific

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Substrate, Hard bottom vs. Soft bottom: This is a preliminary product. Cell values reflect whether the seafloor is hard bottom or soft bottom based on an...

  13. High-frequency bottom-pressure and acoustic variations in a sea strait: internal wave turbulence

    NARCIS (Netherlands)

    van Haren, H.

    2012-01-01

    During a period of 3 days, an accurate bottom-pressure sensor and a four-beam acoustic Doppler current profiler (ADCP) were mounted in a bottom frame at 23 m in a narrow sea strait with dominant near-rectilinear tidal currents exceeding 1 m s(-1) in magnitude. The pressure record distinguishes small

  14. Some man-made and natural radionuclides in the bottom sediments of the Caspian sea

    International Nuclear Information System (INIS)

    Full text : The aim of this study was determination Radionuclides concentration in Caspian Sea sediments in Azerbaijan sector. For the study of the distribution of radionuclides in sea sediment was chosen south-east part of Caspian Sea as investigation zone on the basis of known Sea current systems and, the probability of a relatively uniform distribution of some radionuclides. The bottom sediments collected in different parts of the Caspian Sea were analyzed for some natural and man-made radionuclides. Sample preparation was spent on standard methods. The results confirm that the extraction, transportation and production of oil production in Azerbaijan sector of Caspian Sea didn't change radionuclide background in bottom sediments and dominant source of anthropogenic radionuclides in the Sea environment is global fallout and runoff from rivers Kura and Volga

  15. Degassing of the Black Sea bottom: significance for geological exploration, ecology and navigation

    OpenAIRE

    ШНЮКОВ Е.Ф.; Янко, В. В.

    2015-01-01

    This paper is devoted to a review of modern ideas about degassing (mainly methane) from the bottom of the Black Sea. The main goal is to describe methane emissions on the sea bottom, to delineate their spatial distribution, and to provide insight into their possible origin as well as their influence on ecosystems and navigation. It is shown that the Black Sea is the largest meromictic basin, waters of which are enriched with methane. As such, the basin holds great promise for new energy sourc...

  16. Sea Urchin Recruitment: Effect of Substrate Selection on Juvenile Distribution

    OpenAIRE

    Cameron, R. A.; Schroeter, S. C.

    1980-01-01

    Intertidal field observations have shown that juvenile purple sea urchins Strongylocentwtus purpuratus are found in higher densities near adults . The same is true for subtidal populations of juvenile red sea urchins 5. franciscanus. These distribution patterns could be influenced by any of three elements: substrate selection, early juvenile mortality or juvenile migration. Using laboratory-reared larvae, we conducted experiments designed to gauge the effect of substrate selection on ju...

  17. Morphostructure at the bottom of the Caspian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kulakova, L.S.; Lebedev, L.I.

    1981-01-01

    Heterogenicity of the tectonic structure of the basin is reflected in the nature of its relief. Based on an analysis of echograms and geoacoustic profiles, a detailed description is presented of the relief according to the main morphostructures. A geomorphical map of the Caspian Sea is supplied. On the background of morphostructures, morphostructures are isolated and described: terraces, banks, mud volcanoes, ancient relief, paleochannel, etc.

  18. Fabricating ordered functional nanostructures onto polycrystalline substrates from the bottom-up

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Maria, E-mail: mtorres@drexel.edu; Pardo, Lorena; Ricote, Jesus [Instituto de Ciencia de Materiales de Madrid (Spain); Fuentes-Cobas, Luis E. [Centro de Investigacion en Materiales Avanzados (Mexico); Rodriguez, Brian J. [University College Dublin, Belfield, School of Physics (Ireland); Calzada, M. Lourdes, E-mail: lcalzada@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (Spain)

    2012-10-15

    Microemulsion-mediated synthesis has emerged as a powerful bottom-up procedure for the preparation of ferroelectric nanostructures onto substrates. However, periodical order has yet to be achieved onto polycrystalline Pt-coated Si substrates. Here, we report a new methodology that involves microemulsion-mediated synthesis and the controlled modification of the surface of the substrate by coating it with a template-layer of water-micelles. This layer modifies the surface tension of the substrate and yields a periodic arrangement of ferroelectric crystalline nanostructures. The size of the nanostructures is decreased to the sub-50 nm range and they show a hexagonal order up to the third neighbors, which corresponds to a density of 275 Gb in{sup -2}. The structural analysis of the nanostructures by synchrotron X-ray diffraction confirms that the nanostructures have a PbTiO{sub 3} perovskite structure, with lattice parameters of a = b = 3.890(0) A and c = 4.056(7) A. Piezoresponse force microscopy confirmed the ferro-piezoelectric character of the nanostructures. This simple methodology is valid for the self-assembly of other functional oxides onto polycrystalline substrates, enabling their reliable integration into micro/nano devices.

  19. Increase of carbon dioxide in the bottom water of the Weddell Sea, Antarctica

    NARCIS (Netherlands)

    Hoppema, Mario; Fahrbach, Eberhard; Stoll, Michel H.C.; Baar, Hein J.W. de

    1998-01-01

    High precision total CO2 (TCO2) data are presented from the NW Weddell Sea obtained during two cruises which were 3 years apart. A TCO2 increase from 1993 to 1996 was observed in the newly formed bottom water, whereas no TCO2 increase was found in the surrounding water masses. Accompanying this TCO2

  20. Deep water bottom current deposition in the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    SHAO Lei; LI XueJie; GENG JianHua; PANG Xiong; LEI YongChang; QIAO PeiJun; WANG LiaoLiang; WANG HongBin

    2007-01-01

    There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m, extending from the NE to the SW, leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers suggests that these drifts propagated southwestward, following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current, which enters the northern SCS via the Bashi Strait. Once formed, the bottom currents transport sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity, the deep-sea sedimentary process in the northern SCS is complex.

  1. Probing magnetic bottom and crustal temperature variations along the Red Sea margin of Egypt

    Science.gov (United States)

    Ravat, D.; Salem, A.; Abdelaziz, A.M.S.; Elawadi, E.; Morgan, P.

    2011-01-01

    Over 50 magnetic bottom depths derived from spectra of magnetic anomalies in Eastern Egypt along the Red Sea margin show variable magnetic bottoms ranging from 10 to 34. km. The deep magnetic bottoms correspond more closely to the Moho depth in the region, and not the depth of 580??C, which lies significantly deeper on the steady state geotherms. These results support the idea of Wasilewski and coworkers that the Moho is a magnetic boundary in continental regions. Reduced-to-pole magnetic highs correspond to areas of Younger Granites that were emplaced toward the end of the Precambrian. Other crystalline Precambrian units formed earlier during the closure of ocean basins are not strongly magnetic. In the north, magnetic bottoms are shallow (10-15. km) in regions with a high proportion of these Younger Granites. In the south, the shoaling of the magnetic bottom associated with the Younger Granites appears to be restricted to the Aswan and Ras Banas regions. Complexity in the variation of magnetic bottom depths may arise due to a combination of factors: i) regions of Younger (Precambrian) Granites with high magnetite content in the upper crust, leaving behind low Curie temperature titanomagnetite components in the middle and lower crust, ii) rise in the depth of 580??C isotherm where the crust may have been heated due to initiation of intense magmatism at the time of the Red Sea rifting (~. 20. Ma), and iii) the contrast of the above two factors with respect to the neighboring regions where the Moho and/or Curie temperature truncates lithospheric ferromagnetism. Estimates of fractal and centroid magnetic bottoms in the oceanic regions of the Red Sea are significantly below the Moho in places suggesting that oceanic uppermost mantle may be serpentinized to the depth of 15-30 km in those regions. ?? 2011 Elsevier B.V.

  2. Impressions of the turbulence variability in a weakly stratified, flat-bottom deep-sea ‘boundary layer’

    NARCIS (Netherlands)

    van Haren, H.

    2015-01-01

    The character of turbulent overturns in a weakly stratified deep-sea is investigated in some detail using 144 high-resolution temperature sensors at 0.7 m intervals, starting 5 m above the bottom. A 9-day, 1 Hz sampled record from the 912 m depth flat-bottom (<0.5% bottom-slope) mooring site in the

  3. On the observability of bottom topography from measurements of tidal sea surface height

    Science.gov (United States)

    Zaron, Edward D.

    2016-06-01

    The question of whether features of the ocean bottom topography can be identified from measurements of water level is investigated using a simplified one-dimensional barotropic model. Because of the nonlinear dependence of the sea surface height on the water depth, a linearized analysis is performed concerning the identification of a Gaussian bump within two specific depth profiles, (1) a constant depth domain, and, (2) a constant depth domain adjoining a near-resonant continental shelf. Observability is quantified by examining the estimation error in a series of identical-twin experiments varying data density, tide wavelength, assumed (versus actual) topographic correlation scale, and friction. For measurements of sea surface height that resolve the scale of the topographic perturbation, the fractional error in the bottom topography is approximately a factor of 10 larger than the fractional error of the sea surface height. Domain-scale and shelf-scale resonances may lead to inaccurate topography estimates due to a reduction in the effective number of degrees of freedom in the dynamics, and the amplification of nonlinearity. A realizability condition for the variance of the topography error in the limit of zero bottom depth is proposed which is interpreted as a bound on the fractional error of the topography. Appropriately designed spatial covariance models partly ameliorate the negative impact of shelf-scale near-resonance, and highlight the importance of spatial covariance modeling for bottom topography estimation.

  4. Dynamics simulation of bottom high-sediment sea water movement under waves

    Institute of Scientific and Technical Information of China (English)

    Xueyi YOU; Wei LIU; Houpeng XIAO

    2009-01-01

    The movement of bottom high-sediment sea water under water waves, especially that of the high-sediment water layer close to the sea bottom, is important to the resuspension and settlement of sediment. Supposing that the high-sediment sea water is a Newtonian fluid,based on Navier-Stokes (N-S) theory, the movement of the interfaces of air-water and water-sediment water was tracked by the volume of fluid (VOF) method. The velocity field of sediment water was simulated by considering the effect of water waves. The results show that the movement of sediment water is very different from that of sea water,which provides a solid basis for understanding the resuspension and settlement of sediment and the formation of bottom stripe, and the VOF method can trace the movement of the two interfaces simultaneously; the movement of the air-water interface has a strong effect on that of the water-sediment water interface, while the effect of the water-sediment water interface movement on the air-water interface is not obvious.

  5. The estimation of turnover time in the Japan Sea bottom water by 129I

    International Nuclear Information System (INIS)

    It is well known that the Japan Sea is sensitive for the environment such a global warming. To understand the oceanic circulation in the Japan Sea, we estimated a turnover time and a potential formation rate of the Japan Sea bottom water (JSBW) using an oceanographic tracer of 129I. The turnover time of JSBW was calculated based on the increased concentration during the nuclear era. The turnover time was estimated to be 180 - 210 years. The potential formation rate of JSBW is calculated based on the existence of the anthropogenic 129I in the JSBW. The potential formation rate of JSBW is estimated to be (3.6-4.1) x 1012 m3/y which is consistent with another estimation and is about quarter of that of the upper Japan Sea proper water. (author)

  6. Interactions Between Ice Thickness, Bottom Ice Algae, and Transmitted Spectral Irradiance in the Chukchi Sea

    Science.gov (United States)

    Arntsen, A. E.; Perovich, D. K.; Polashenski, C.; Stwertka, C.

    2015-12-01

    The amount of light that penetrates the Arctic sea ice cover impacts sea-ice mass balance as well as ecological processes in the upper ocean. The seasonally evolving macro and micro spatial variability of transmitted spectral irradiance observed in the Chukchi Sea from May 18 to June 17, 2014 can be primarily attributed to variations in snow depth, ice thickness, and bottom ice algae concentrations. This study characterizes the interactions among these dominant variables using observed optical properties at each sampling site. We employ a normalized difference index to compute estimates of Chlorophyll a concentrations and analyze the increased attenuation of incident irradiance due to absorption by biomass. On a kilometer spatial scale, the presence of bottom ice algae reduced the maximum transmitted irradiance by about 1.5 orders of magnitude when comparing floes of similar snow and ice thicknesses. On a meter spatial scale, the combined effects of disparities in the depth and distribution of the overlying snow cover along with algae concentrations caused maximum transmittances to vary between 0.0577 and 0.282 at a single site. Temporal variability was also observed as the average integrated transmitted photosynthetically active radiation increased by one order of magnitude to 3.4% for the last eight measurement days compared to the first nine. Results provide insight on how interrelated physical and ecological parameters of sea ice in varying time and space may impact new trends in Arctic sea ice extent and the progression of melt.

  7. Iceberg ploughmark features on bottom surface of the South-Eastern Baltic Sea

    Science.gov (United States)

    Dorokhov, Dmitry; Sivkov, Vadim; Dorokhova, Evgenia; Krechik, Viktor

    2016-04-01

    A detail swath bathymetry, side-scan sonar and acoustic profiling combined with sediment sampling during the 64th cruise of RV "Academic Mstislav Keldysh" (October 2015) allowed to identify new geomorphological features of the South-Eastern Baltic Sea bottom surface. The extended chaotic ploughmarks (furrows) in most cases filled with thin layer of mud were discovered on surface of the Gdansk-Gotland sill glacial deposits. They are observed on the depth of more than 70 m and have depth and width from 1 to 10 m. Most of them are v- or u-shaped stepped depressions. The side-scan records of similar geomorpholoical features are extensively reported from Northern Hemisphere and Antarctica (Goodwin et al., 1985; Dowdeswell et al., 1993). Ploughmarks are attributed to the action of icebergs scouring into the sediment as they touch bottom. We are suggest that furrows discovered in the South-Eastern Baltic Sea are also the result of iceberg scouring during the Baltic Ice Lake stage (more than 11 600 cal yr BP (Bjorck, 2008)). This assumption confirmed by occurrence of fragmental stones and boulders on the sea bottom surface which are good indicators of iceberg rafting (Lisitzin, 2003). Ice ploughmarks at sea bottom surface were not occurred before in the South-Eastern Baltic Sea. The study was financed by Russian Scientific Fund, grant number 14-37-00047. References Bjorck S. The late Quaternary development of the Baltic Sea Basin. In: The BACC Author Team (eds) Assessment of climate change for the Baltic Sea Basin. Springer, Berlin, Heidelberg. 2008. Dowdeswell J. A., Villinger H., Whittington R. J., Marienfeld P. Iceberg scouring in Scoresby Sund and on the East Greenland continental shelf // Marine Geology. V. 111. N. 1-2. 1993. P. 37-53. Goodwin C. R., Finley J. C., Howard L. M. Ice scour bibliography. Environmental Studies Revolving Funds Report No. 010. Ottawa. 1985. 99 pp. Lisitzin A. P. Sea-Ice and Iceberg Sedimentation in the Ocean: Recent and Past. Springer

  8. Ocean Bottom Pressure Records at the Permanent Service for Mean Sea Level

    Science.gov (United States)

    Hibbert, Angela; Matthews, Andrew; Hughes, Chris W.; Tamisiea, Mark E.

    2014-05-01

    As part of a research effort funded by the U.K. Natural Environment Research Council, the Permanent Service for Mean Sea Level (PSMSL) has been developing a repository of data from in-situ ocean bottom pressure recorders (OBPRs) from all possible sources. The data are being processed to a common format using a consistent methodology so that time series are directly comparable. Efforts are also being made to ensure that data are accompanied by comprehensive metadata. The OBPR data are supplied primarily for hourly and daily intervals, making them ideal for studies of tidal to seasonal variability. In addition, because bottom pressure recorders measure changes in ocean mass, these data are an ideal complement to GRACE satellite data and a useful accompaniment to sea level data from tide gauges and altimetry. Consequently, it is anticipated that the PSMSL OBPR repository will become a valuable product to the scientific community.

  9. Seasonal and inter-annual temperature variability in the bottom waters over the Black Sea shelf

    Directory of Open Access Journals (Sweden)

    G. I. Shapiro

    2011-02-01

    Full Text Available Long-term changes in the state of the Bottom Shelf Water (BSW on the Western shelf of the Black Sea are assessed using analysis of intra- and inter-annual variations of temperature as well as their relations to physical parameters of both shelf and deep-sea waters. First, large data sets of in-situ observations over the 20th century are compiled into high-resolution monthly climatology at different depth levels. Then, the temperature anomalies from the climatic mean are calculated and aggregated into spatial compartments and seasonal bins to reveal temporal evolution of the BSW. For the purpose of this study the BSW is defined as such shelf water body between the seabed and the upper mixed layer (bounded by the σθ = 14.2 isopycnal which has limited ability to mix vertically with oxygen-rich surface waters during the warm season (May–November due to the formation of a seasonal pycnocline. The effects of atmospheric processes at the surface on the BSW are hence suppressed as well as the action of the "biological pump". The vertical extent of the near- bottom waters is determined based on energy considerations and the structure of the seasonal pycnocline, whilst the horizontal extent is controlled by the shelf break, where strong along-slope currents hinder exchanges with the deep sea. The BSW is shown to occupy nearly half of the area of the shelf during the summer stratification period. The potential of the BSW to ventilate horizontally during the warm season with the deep-sea waters is assessed using isopycnic analysis of temperature variations. A long-term time series of temperature anomalies in the BSW is constructed from observations during the May–November period for the 2nd half of the 20th century. The results reveal a warm phase in the 1960s/70s, followed by cooling of the BSW during 1980–2001. The transition between the warm and cold periods coincides with a regime shift in the Black Sea ecosystem. While it was

  10. Effect of the Bottom Topography on Tsunami Propagation in the East (Japan) Sea

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A study of tsunami events in the East (Japan) Sea using continuous Galerkin finite element model, aiming at reproducing tsunami waves generated by underwater earthquakes in 1983 and 1993 respectively has been performed focusing on the geographic extent of a topographic feature in the East (Japan) Sea. Numerical models can be the proper tools to study the combined effects of realistic topography. Subsequently, using the FEM based two-dimensional model we have simulated the smoothed and flattened topographic effects by removal of Yamato Rise and seamounts for the cases of tthe 1983 Central region earthquake tsunami and the 1993 southwestern Hokkaido earthquake tsunami. The results have shown that there will be higher tsunamis along the eastern coasts of Korea in general except some areas, like Sokcho with removal of topographic highs, thus providing complicated bottom topography of the East (Japan) Sea as effective tsunami energy scattering.

  11. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were...

  12. Observations of Seasonal Variations in Sea Bottom Temperature and Salinity in Bykovsky Bay in the Laptev Sea

    Science.gov (United States)

    Overduin, P. P.; Grigoriev, M. N.; Kopsch, C.

    2009-04-01

    Following inundation due to coastal erosion or increasing relative sea level, flooded permafrost is separated from the atmosphere by sea ice and water. The boundary condition for further permafrost evolution is given by seabed salinity and temperature. Few records of seasonal variations in these parameters exist, limiting our ability to predict the speed of subsea peramfrost degradation, or to correlate borehole observations with near-shore processes. For subsea permafrost, seabottom temperature drives sediment warming and variations in salinity can increase the rate of penetration of the seawater salt front into the sediment. A borehole transect drilled in 1983 in the nearshore zone off Mamontovy Khayata on the Bykovsky Peninsula in the Laptev Sea resulted in a description of subsea sediment temperature and the inclination of the top of the ice-bearing permafrost perpendicular to the coast out to a distance of 3 km. Before erosion, the landscape at Mamontovy Khayata is composed of ice-rich periglacial deposits down to and beneath current sea level, most of which are removed during erosion. Thermokarst features dominate the landscape and affect coastal bluff height and the resilience of sediments to coastal erosion and abrasion. We installed dataloggers on the seabed in 2007 to measure bottom water temperature and salinity at hourly intervals. Temperature variations are higher than expected, and together with salinity demonstrate the changing seasonal importance of warm, fresh river water and colder, saltier sea water that has been observed elsewhere. During winter, bottom water temperatures stabilize at the freezing point, but rise slowly during the winter, during a period of increasing salinity. We propose that this warming corresponds to the loss of heat from the underlying sediment. We compare integrated rates of warming of subsea and terrestrial permafrost and estimate the increase in the rate of subsea permafrost thermal degradation after inundation.

  13. Impressions of the turbulence variability in a weakly stratified, flat-bottom deep-sea ‘boundary layer’

    OpenAIRE

    H. van Haren

    2015-01-01

    The character of turbulent overturns in a weakly stratified deep-sea is investigated in some detail using 144 high-resolution temperature sensors at 0.7 m intervals, starting 5 m above the bottom. A 9-day, 1 Hz sampled record from the 912 m depth flat-bottom (

  14. Deep Sea Coral voucher sequence dataset - Identification of deep-sea corals collected during the 2009 - 2014 West Coast Groundfish Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data for this project resides in the West Coast Groundfish Bottom Trawl Survey Database. Deep-sea corals are often components of trawling bycatch, though their...

  15. Influence of submarine morphology on bottom water flow across the western Ross Sea continental margin

    Science.gov (United States)

    Davey, F.J.; Jacobs, S.S.

    2007-01-01

    Multibeam sonar bathymetry documents a lack of significant channels crossing outer continental shelf and slope of the western Ross Sea. This indicates that movement of bottom water across the shelf break into the deep ocean in this area is mainly by laminar or sheet flow. Subtle, ~20 m deep and up to 1000 m wide channels extend down the continental slope, into tributary drainage patterns on the upper rise, and then major erosional submarine canyons. These down-slope channels may have been formed by episodic pulses of rapid down slope water flow, some recorded on bottom current meters, or by sub-ice melt water erosion from an icesheet grounded at the margin. Narrow, mostly linear furrows on the continental shelf thought to be caused by iceberg scouring are randomly oriented, have widths generally less than 400 m and depths less than 30m, and extend to water depths in excess of 600 m.

  16. Scour protection for wind turbine foundations on highly erodible sea bottom

    Energy Technology Data Exchange (ETDEWEB)

    Ottesen Hansen, N.E.

    2002-12-01

    Scour around offshore structures is well known. It is caused by the strong eddy formation at the base of the structures protruding from the sea bottom. The strong vortices result in an amplified effective shear stress working on the sea bottom surface adjacent to the structure. When the surrounding sea bottom is lowered the scour protection will end up being a cap on a small hill and when the slopes are getting too steep the scour protection will roll or slide down the sides. It will loose its cohesion and therefore its integrity. This will take place irrespective of the type of scour protection material and the type of scour protection. This report describes scour protections, which can deal with this particular problem. Such a scour protection must be able to sustain the following loads: Be able to follow the lowering of the seabed on its way down; Be resistant to edge scour (scour around the perimeter of the scour protection). The installation of scour protection is not straightforward because the developed scour hole may be very uneven. It will be highly impractical to survey the hole although it can be done. There will be power cables etc. obstructing for ROV's or instrumented backhoe arms. Therefore the recommended method is to assume that the scour hole is developed and to place the scour protection material evenly around the foundation. In practice this is done by fall pipes positioned from a barge or by an instrumented backhoe. The procedure will be as follows: The outline of the scour hole is surveyed by a ROV (eye ball) and the status of the power cables are investigated; If the tie-in of the power cables are hanging as free spans, material shall be dumped on these spans in order to cover them. This material shall have a size, which will not be harmful to the cable during a dumping; Alternatively the tie-in takes place through an armoured flex-pipe that can sustain the impact from the stone dumping. Hence, in this case the stone dumping can commence

  17. Acoustic monitoring in the Ross Sea, Antarctica, using hydrophone of the Ocean Bottom Seismometer

    Science.gov (United States)

    Yun, Sukyoung; Lee, Won Sang; Kuk Hong, Jong; Yoo, Hyun Jae; Park, Yongcheol; Schmidt-Aursch, Mechita; Geissler, Wolfram H.

    2016-04-01

    Although a number of active source seismic experiments have been conducted over the last few decades to investigate the crustal structure in the Ross Sea, Antarctica, long-term observation to monitor underwater tectonic activities and changes in the cryospheric environment still remains challenging due to existence of sea ice in the study region. Korea Polar Research Institute has accomplished successful deployment of ocean bottom seismometers (OBS) in the Ross Sea collaborating with Alfred Wegener Institute during the period of 2011-2012 and 2014 by Korean icebreaker RV Araon. The OBS system manufactured by K.U.M. contains a hydrophone sensor that allow us to monitor underwater acoustics generated by tectonic and ice-related events. We present spectrograms of the continuous hydroacoustic data and various types of signals, e.g. seismic T-waves, iceequakes, and tremors. There are periodic and harmonic tremors that might be related with tidal modulation, and the seasonal variation of the background noise seems to be related with sea ice concentration.

  18. Optimization and evaluation of a bottom substrate denitrification tank for nitrate removal from a recirculating aquaculture system.

    Science.gov (United States)

    Pungrasmi, Wiboonluk; Playchoom, Cholticha; Powtongsook, Sorawit

    2013-08-01

    A bottom substrate denitrification tank for a recirculating aquaculture system was developed. The laboratory scale denitrification tank was an 8 L tank (0.04 m2 tank surface area), packed to a depth of 5 cm with a bottom substrate for natural denitrifying bacteria. An aquarium pump was used for gentle water mixing in the tank; the dissolved oxygen in the water was maintained in aerobic conditions (e.g. > 2 mg/L) while anoxic conditions predominated only at the bottom substrate layer. The results showed that, among the four substrates tested (soil, sand, pumice stone and vermiculite), pumice was the most preferable material. Comparing carbon supplementation using methanol and molasses, methanol was chosen as the carbon source because it provided a higher denitrification rate than molasses. When methanol was applied at the optimal COD:N ratio of 5:1, a nitrate removal rate of 4591 +/- 133 mg-N/m2 tank bottom area/day was achieved. Finally, nitrate removal using an 80 L denitrification tank was evaluated with a 610 L recirculating tilapia culture system. Nitrate treatment was performed by batch transferring high nitrate water from the nitrification tank into the denitrification tank and mixing with methanol at a COD:N ratio of 5:1. The results from five batches of nitrate treatment revealed that nitrate was successfully removed from water without the accumulation of nitrite and ammonia. The average nitrate removal efficiency was 85.17% and the average denitrification rate of the denitrification tank was 6311 +/- 945 mg-N/m2 tank bottom area/day or 126 +/- 18 mg-N/L of pumice packing volume/day. PMID:24520693

  19. Optimization and evaluation of a bottom substrate denitrification tank for nitrate removal from a recirculating aquaculture system

    Institute of Scientific and Technical Information of China (English)

    Wiboonluk Pungrasmi; Cholticha Playchoom; Sorawit Powtongsook

    2013-01-01

    A bottom substrate denitrification tank for a recirculating aquaculture system was developed.The laboratory scale denitrification tank was an 8 L tank (0.04 m2 tank surface area),packed to a depth of 5 cm with a bottom substrate for natural denitrifying bacteria.An aquarium pump was used for gentle water mixing in the tank; the dissolved oxygen in the water was maintained in aerobic conditions (e.g.> 2 mg/L) while anoxic conditions predominated only at the bottom substrate layer.The results showed that,among the four substrates tested (soil,sand,pumice stone and vermiculite),pumice was the most preferable material.Comparing carbon supplementation using methanol and molasses,methanol was chosen as the carbon source because it provided a higher denitrification rate than molasses.When methanol was applied at the optimal COD∶N ratio of 5∶1,a nitrate removal rate of 4591 ± 133 mg-N/m2 tank bottom area/day was achieved.Finally,nitrate removal using an 80 L denitrification tank was evaluated with a 610 L recirculating tilapia culture system.Nitrate treatment was performed by batch transferring high nitrate water from the nitrification tank into the denitrification tank and mixing with methanol at a COD∶N ratio of 5∶1.The results from five batches of nitrate treatment revealed that nitrate was successfully removed from water without the accumulation of nitrite and ammonia.The average nitrate removal efficiency was 85.17% and the average denitrification rate of the denitrification tank was 6311 ± 945 mg-N/m2 tank bottom area/day or 126 ± 18 mg-N/L of pumice packing volume/day.

  20. Application of model studies for quality control of bottom pressure based GLOSS sea level gauge at Takoradi Harbour (Ghana, West Africa)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Mehra, P.; Desai, R.G.P.; Dotse, J.; Odammetey, J.T.; Nkebi, E.K.; VijayKumar, K.; Prabhudesai, S.

    Quality-control of bottom pressure based sea level gauge has been effected using a statistically derived simple linear model constructed from a set of bottom pressures and concurrent tide-staff measurements. The study reveals that the crucial factor...

  1. The nematode fauna of a deep-sea site exposed to strong near-bottom currents

    Science.gov (United States)

    Thistle, David; Sherman, Kevin M.

    1985-09-01

    Nematodes are the most abundant metazoans in marine soft-bottom habitats, yet little is known of their role in deep-sea communities. We describe the nematode fauna from 4626 m depth in the North Atlantic (40°24.0'N, 63°07.4'W) at the family and genus level and compare our findings to previous reports on deep-sea nematodes. The results of covariance studies between nematodes and environmental parameters are also given. At the species level, there is no evidence of association between small-scale variation in nematode abundance and variation in abundance of bacteria or several classes of biogenous structures, but there is evidence of an association with pebbles. At the functional-group level, feeding groups show no correlation with environmental variables, nor do groups based on tail morphology. However, four of the tail-morphology groups are significantly disproportionately abundant in either the 0 to 1 or the 1 to 2 cm sediment layer. Individuals of one group may use their long, retractable tails to escape into the sediment to avoid resuspension by noncatastrophic erosive flows, which are common at this hydrodynamically active deep-sea locality.

  2. Impacts of open-ocean deep convection in the Weddell Sea on coastal and bottom water temperature

    Science.gov (United States)

    Wang, Zhaomin; Wu, Yang; Lin, Xia; Liu, Chengyan; Xie, Zelin

    2016-07-01

    A high resolution global ocean-sea ice model is employed to investigate the impacts of open-ocean deep convection on coastal and bottom water temperature in the Weddell Sea. The imposed strong and persistent cyclonic wind forcing and the large loss of bottom water weaken the stratification and eventually trigger the occurrence of open-ocean deep convection in the southern limb of the Weddell Gyre in this model. The production rate of the bottom water induced by the deep convection is estimated to be about 5 Sv (1 Sv = 106 m3/s) for a polynya with a similar size to that of the observed Weddell Polynya in the mid-1970s. The cooling induced by deep convection at mid-depth is transported towards the shelf regions by standing meanders or eddies to affect the basal melting of ice shelves, and is transported westward by an intensified slope current; interior coastal temperature in regions with a broader continental shelf is less affected by the deep convection, as the intensified slope current acts to suppress heat exchanges across the shelf break. Also, the deep convection causes warming in the Weddell bottom water around the convection site, when the simulated polynya size is similar to that of the observed Weddell Polynya in the mid-1970s. This finding sheds light on the observed non-monotonic decadal change (cooling between 1984-1992 and warming between 1998-2008) in the Weddell bottom water temperature. When the simulated polynya further develops into a large size across the Weddell Sea, the sustained broad deep convection causes large cooling in the bottom water in the western Weddell Sea and warming in the eastern Weddell Sea, with the bottom water temperature also being strongly modulated by a greatly intensified Weddell Gyre.

  3. Bottom melting of Arctic Sea Ice in the Nansen Basin due to Atlantic Water influence

    Science.gov (United States)

    Muilwijk, Morven; Smedsrud, Lars H.; Meyer, Amelie

    2016-04-01

    sea ice. Because of the large increase in AW temperature over the last 30 years we assume that perturbations in the AW are important drivers of location of AW in this region, and that the sea ice and polar water above is passively responding to the AW variability. Previously it has been argued that the warming of AW could not contribute to increased ice melting because of the strong stratification. Our observations show an ice cover around 2 m, but with active ice formation in between the larger and thicker floes. The ongoing freezing drives brine release and subsequent convection, contributing to the deep ~100 m mixed layer observed in the area until mid-May. Onwards from May solar heating is stratifying the upper layer by adding heat. Data analysis is ongoing but indicates that location of AW is an important factor in bottom melting in the area north of Svalbard. Location of AW and related bottom melting will be evaluated using simulations from a fully coupled climate model.

  4. Investigation on Touching Sea Bottom by a FPSO in Bohai Oilfield with Shallow Water

    Institute of Scientific and Technical Information of China (English)

    LI Xin; YANG Jianmin; FAN Mo

    2005-01-01

    As one of the key safety problems, the motion performance and touching sea bottom of a FPSO are paid much attention by the ocean oil companies when the FPSO is exposed to survival storms in the shallow-water working areas. In this paper, timedomain numerical simulations are carried out on a 160 kDWT FPSO with a Yoke mooting system moored in the BZ25-1 oilfield with a water depth of 16.7m. The results are compared with those of the corresponding model tests. Good agreement shows that the time-domain simulations can be used to predict the performance of the FPSO in shallow-water reasonably. It is found that the touch of seabed by a fully loaded FPSO occurred few times under survival storm conditions. Therefore, the FPSO should be less loaded than that in the fully loaded condition under the survival storms.

  5. 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.

  6. Evolution of the deep and bottom waters of the Scotia Sea, Southern Ocean, during 1995-2005

    OpenAIRE

    Meredith, Michael P.; Naveira Garabato, Alberto C.; Gordon, Arnold L.; Johnson, Gregory C.

    2008-01-01

    The Southern Ocean hosts the formation of the densest layers of the oceanic overturning circulation, and provides a climatically sensitive element of deep ocean ventilation. An oceanographic section across the eastern Scotia Sea occupied in 1995, 1999 and 2005 reveals significant variability in the deep and bottom waters of Southern Ocean origin. Warming (~0.1ºC) of the warm mid-layer waters in the Scotia Sea between 1995 and 1999 reversed through to 2005, reflecting changes seen earlier up...

  7. Isotope and geochemical parameters of hydrocarbon gases in bottom sediments of the shelf of the East Siberian Sea

    Science.gov (United States)

    Gresov, A. I.; Shakhova, N. E.; Sergiyenko, V. I.; Yatsuk, A. V.; Semiletov, I. P.

    2016-08-01

    The research results on gas geochemistry of hydrocarbon gases in bottom sediments of the East Siberian Sea are presented. The key isotope and geochemical parameters of syn- and epigenetic hydrocarbon gases are determined. The correlations between the molecular masses of hydrocarbon fractions and the carbon isotope composition on hydrocarbon gases of various origin are revealed.

  8. Forms of metals in bottom sediments from some estuaries of the basins of the White and Barents seas

    NARCIS (Netherlands)

    Kukina, S.E.; Sadovnikova, L.K.; Calafat-Frau, A.; Palerud, R.; Hummel, H.

    1999-01-01

    The abundances of exchangeable, organic-bonded, and strongly bonded mineral species of Fe, Mn, Zn, Ni, Cr, Cu, Pb, and Co were determined in samples of bottom sediments from five estuaries of the basins of the White and Barents Seas by using a modified sequential extraction method, which was initial

  9. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    Science.gov (United States)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  10. Hydrocarbons in waters and bottom sediments of coastal areas in the northeastern part of the Black Sea

    Science.gov (United States)

    Nemirovskaya, I. A.; Lisitzin, A. P.

    2015-09-01

    Data on the content and composition of aliphatic and polycyclic aromatic hydrocarbons in the surface layer of water and bottom sediments are presented. The data were compared to the distribution of the total organic carbon, particulate matter, lipids, and chlorophyll in the Gelendzhik and Golubaya bays, as well as in the Greater Sochi area. The intense transformation processes of organic compounds within the water mass and water-bottom interface have resulted in the prevalence of natural components in the alkane composition of the bottom sediments in the areas of the Black Sea considered. The riverine and marine water mixing zone acts as a geochemical barrier preventing the supply of the bulk of river-transferred pollutants to the open sea areas.

  11. Bottom-up and top-down controls on picoplankton in the East China Sea

    Science.gov (United States)

    Guo, C.; Liu, H.; Zheng, L.; Song, S.; Chen, B.; Huang, B.

    2013-05-01

    Dynamics of picoplankton population distribution in the East China Sea (ECS), a marginal sea in the western North Pacific Ocean, were studied during two "CHOICE-C" cruises in August 2009 (summer) and January 2010 (winter). Dilution experiments were conducted during the two cruises to investigate the growth and grazing among picophytoplantkon populations. Picoplankton accounted for an average of ~29% (2% to 88%) of community carbon biomass in the ECS on average, with lower percentages in plume region than in shelf and kuroshio regions. Averaged growth rates (μ) for Prochlorococcus (Pro), Synechococcus (Syn) and picoeukaryotes (peuk) were 0.36, 0.89, 0.90 d-1, respectively, in summer, and 0.46, 0.58, 0.56 d-1, respectively, in winter. Seawater salinity and nutrient availability exerted significant controls on picoplankton growth rate. Averaged grazing mortality (m) were 0.46, 0.63, 0.68 d-1 in summer, and 0.22, 0.32, 0.22 d-1 in winter for Pro, Syn and peuk respectively. The three populations demonstrated very different distribution patterns regionally and seasonally affected by both bottom-up and top-down controls. In summer, Pro, Syn and peuk were dominant in Kuroshio, transitional and plume regions respectively. Protist grazing consumed 84%, 78%, 73% and 45%, 47%, 57% of production for Pro, Syn and peuk in summer and winter respectively, suggesting more significant top-down controls in summer. In winter, all three populations tended to distribute in offshore regions, although the area of coverage was different (peuk > Syn > Pro). Bottom-up factors can explain as much as 91.5%, 82% and 81.2% of Pro, Syn and peuk abundance variance in winter, while only 59.1% and 43.7% for Pro and peuk in summer. Regionally, Yangtze River discharge plays a significant role in affecting the intensity of top-down control, indicated by significant and negative association between salinity and grazing mortality of all three populations and higher grazing mortality to growth rate ratio

  12. Molecular genetic diversity of bacteria in the bottom section of arctic sea ice from the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    LI Huirong; YU Yong; CHEN Bo; ZENG Yinxin; REN Daming

    2005-01-01

    PCR-DGGE approach was used to analyze bacterial diversity in the bottom section of seven arctic sea ice samples colleted from the Canada Basin. Thirty-two 16S rDNA sequences were obtained from prominent DGGE bands. The closest relatives of these sequences are found to be those of cultivated or uncultured bacteria from antarctic or arctic sea ice. Phylogenetic analysis clustered these sequences or phylotypes within α- proteobacteria, γ-proteobacteria and CFB (cytophaga-flexibacter-bacteroides) group. Sequences belonging to γ-proteobacteria were dominant and members of the CFB group were highly abundant. It was suggested that the CFB group was the representative of the bottom section of sea ice samples.

  13. Electromagnetic fields at the sea bottom induced by a line of immersed electric dipoles

    Directory of Open Access Journals (Sweden)

    Edson E.S. Sampaio

    2011-09-01

    Full Text Available The analysis of electromagnetic fields caused by alternate or transient electric currents flowing along a cable in sea water has several applications. It supports the interpretation of electromagnetic geophysical data and safety procedures against the threat of sea mines. The approach to the problem employs a magnetic vector potential in the frequency domain due to a pulse source electric dipole, and performs Laplace and Hankel transforms and integration along the cable, to describe the variation of the magnetic induction field due to an electric dipole of finite length. The result is applicable to shallow or deep sea water environments, adaptable to any transmitting current waveform and useful for wave-field separation. The prospects relate to a horizontal receiving coil at the sea bottom and simulate: a minesweeper campaign with a current source at the sea surface or a geophysical survey with a current source close to the sea floor. Therefore, the present analysis may serve: to define parameters in counter-sweeping of submarine mines; to map the conductivity of sediments under shallow waters for the prevention and control of contamination; and as a first approach in the characterization of offshore mineral and oil economic deposits.A análise de campos eletromagnéticos causados por correntes alternadas ou transientes fluindo ao longo de um cabo na água do mar tem várias aplicações. Ela prove suporte à interpretação de dados geofísicos eletromagnéticos e aos procedimentos de segurança contra a ameaça de minas submarinas. A abordagem do problema emprega um potencial vetorial magnético, no domínio da frequência, devido a um dipolo elétrico com uma fonte tipo pulso e calcula transformações de Laplace e de Hankel e integração ao longo do comprimento do cabo, para descrever a variação temporal do campo magnético de indução devido a um dipolo elétrico de comprimento finito. O resultado é aplicável em ambientes de água do

  14. Latitudinal trends and temporal shifts in the catch composition of bottom trawls conducted on the eastern Bering Sea shelf

    Science.gov (United States)

    Stevenson, Duane E.; Lauth, Robert R.

    2012-06-01

    Latitudinal species diversity gradients are well known in both terrestrial and aquatic ecosystems throughout the world. However, trends in relative abundance and other shifts in community structure with latitude, which can be more sensitive to environmental shifts such as climate change, have received less attention. Here we investigate latitudinal trends in the seafloor community of the eastern Bering Sea using catches of fishes and epibenthic invertebrates in bottom trawl surveys conducted from 1982 to 2010. Our results indicate that the overall biomass of the epibenthic community declines with increasing latitude in the eastern Bering Sea. This latitudinal trend is primarily driven by declining fish catches in the northern Bering Sea, which in turn reflects changes in the structure of the fish community. The fish fauna in northern latitudes is increasingly dominated by gadids, though the species composition of the gadid fauna also changes with latitude, with smaller species becoming more common in the north. The biomass of the invertebrate megafauna remains relatively consistent throughout the eastern Bering Sea, but invertebrates make up a larger proportion of the catch in bottom trawls conducted at higher latitudes. The epibenthic invertebrate megafauna in the eastern Bering Sea is composed primarily of sea stars (Asteriidae) and oregoniid crabs (Chionoecetes and Hyas), though no clear latitudinal trends in the invertebrate community are evident. Limited trawl data from the eastern Chukchi Sea indicate that the fish community farther north is even more heavily dominated by gadids, and the epibenthic invertebrate community is dominated by asteriid sea stars. Temperature data from bottom trawl surveys in the southeastern Bering Sea over the past decade indicate that there was a distinct temperature shift around 2005, and the relatively warm years of 2001-2005 were followed by five relatively cold years. This shift in the summer temperature regime of the Bering

  15. Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Komazawa, M. [Geological Survey of Japan, Tsukuba (Japan); Ota, Y.; Shibuya, S.; Kumai, M.; Murakami, M. [Japex Geoscience Institute, Inc., Tokyo (Japan)

    1996-05-01

    This paper reports a sea bottom gravity survey conducted with an objective to identify deep underground structure in the vicinity of the epicenter of the Hyogoken-Nanbu Earthquake. The surveyed areas are the whole Osaka Bay area north of the north latitude of 34 degrees and 20 minutes, and the eastern part of the Sea of Harima east of the east longitude of 134 degrees and 40 minutes, excluding the areas difficult of performing measurements. A square lattice with sides each about 2 km was arranged with 408 measurement points. The measurement was carried out by using an observation vessel mounted with a sea bottom gravimeter made by LaCoste and Romberg Corporation, which was lowered down to the sea bottom at the measurement points. Errors in positions and water depths at the gravity measuring points were suppressed to less than 0.002 minutes and 0.1 m, respectively. The measurement data were given necessary corrections by using a unified method applicable also to land areas, and a Bouguer anomaly chart was prepared. Based on the chart, this paper summarizes features in the Bouguer anomaly in the surveyed areas (such as the low-gravity anomaly band extending the central part of the Osaka bay from north-east to south-west, and the gradient structure existing on the Awaji island side). 6 refs., 1 fig.

  16. Colonization of over a thousand Cibicidoides wuellerstorfi (foraminifera: Schwager, 1866) on artificial substrates in seep and adjacent off-seep locations in dysoxic, deep-sea environments

    Science.gov (United States)

    Burkett, Ashley M.; Rathburn, Anthony E.; Elena Pérez, M.; Levin, Lisa A.; Martin, Jonathan B.

    2016-11-01

    After ~1 yr on the seafloor at water depths of ~700 m on Hydrate Ridge in the Pacific, eight colonization experiments composed primarily of a plastic mesh cube (from here on refered to as SEA3, for Seafloor Epibenthic Attachment Cubes) were colonized by 1076 Cibicidoides wuellerstorfi on ~1841 cm2 of experimental substrate. This species is typically considered an indicator of well-oxygenated conditions, and recruitment of such large numbers in bottom waters with low dissolved oxygen availability (0.24-0.37 mL/L) indicate that this taxon may not be as limited by oxygen as previously thought. Clues about substrate preferences were evident from the distribution, or lack thereof, of individuals among plastic mesh, coated steel frame, wooden dowels and reflective tape. Abundance, individual size distributions within cage populations and isotopic biogeochemistry of living foraminifera colonizing experimental substrates were compared between active seep and adjacent off-seep experiment locations, revealing potential differences between these environments. Few studies have examined foraminiferal colonization of hard substrates in the deep-sea and to our knowledge no previous study has compared foraminiferal colonization of active seep and off-seep substrates from the same region. This study provides initial results of recruitment, colonization, geochemical and morphological aspects of the paleoceanographically significant species, C. wuellerstorfi, from dynamic deep-sea environments. Further experimental deployments of SEA3s will provide a means to assess relatively unknown ecologic dynamics of important foraminiferal deep-sea species.

  17. A Determination of an Abrupt Motion of the Sea Bottom by Using Snapshot Data of Water Waves

    Directory of Open Access Journals (Sweden)

    T. S. Jang

    2012-01-01

    Full Text Available This paper presents an inverse problem and its solution procedure, which are aimed at identifying a sudden underwater movement of the sea bottom. The identification is mathematically shown to work with a known snapshot data of generated water wave configurations. It is also proved that the problem has a unique solution. However, the inverse problem is involved in an integral equation of the first kind, resulting in an ill-posed problem in the sense of stability. That is, the problem lacks solution stability properties. To overcome the difficulty of solution instability, in this paper, a stabilization technique, called regularization, is incorporated in the present solution procedure for the identification of the sea bottom movement. A numerical experiment is presented to demonstrate that the proposed (numerical solution procedure operates.

  18. Influence of Ross Sea Bottom Water changes on the warming and freshening of the Antarctic Bottom Water in the Australian-Antarctic Basin

    Directory of Open Access Journals (Sweden)

    K. Shimada

    2012-07-01

    Full Text Available Changes to the properties of Antarctic Bottom Water in the Australian-Antarctic Basin (AA-AABW between the 1990s and 2000s are documented using data from the WOCE Hydrographic Program (WHP and repeated hydrographic surveys. Strong cooling and freshening are observed on isopycnal layers denser than γn = 28.30 kg m−3. Changes in the average salinity and potential temperature below this isopycnal correspond to a basin-wide warming of 1300 ± 200 GW and freshening of 24 ± 3 Gt year−1. Recent changes to dense shelf water in the source regions in the Ross Sea and George V Land can explain the freshening of AA-AABW but not its extensive warming. An alternative mechanism for this warming is a decrease in the supply of AABW from the Ross Sea (RSBW. Hydrographic profiles between the western Ross Sea and George V Land (171–158° E were analyzed with a simple advective-diffusive model to assess the causes of the observed changes. The model suggests that the warming of RSBW observed between the 1970s and 2000s can be explained by a 21 ± 23% reduction in RSBW transport and the enhancement of the vertical diffusion of heat resulting from a 30 ± 7% weakening of the abyssal stratification. The documented freshening of Ross Sea dense shelf water leads to a reduction in both salinity and density stratification. Therefore the direct freshening of RSBW at its source also produces an indirect warming of the RSBW. A simple box model suggests that the changes in RSBW properties and volume transport (a decrease of 6.7% is assumed between the year 1995 and 2005 can explain 51 ± 6% of the warming and 84 ± 10% of the freshening observed in AA-AABW.

  19. Numerical simulation of the dual-core structure of the Bohai Sea cold bottom water in summer

    Institute of Scientific and Technical Information of China (English)

    ZHOU Feng; HUANG DaJi; SU JiLan

    2009-01-01

    Regional Ocean Modeling Systems (ROMS 3.0) and the K-ε turbulence closure scheme has been ap-plied to investigating the seasonal evolution of the thermsocline in the Bohsi Sea. The simulation re-produces the stratifications lasting from early April to early September and reveals the existence of marked Asymmetric Dual-Core Cold Bottom Water (ADCCBW) in the south and north depression basin respectively under the thermocline. The bottom temperature in the north depression is about 1-4℃ lower than that in the south depression basin which is in good agreement with observations. Model results suggest that the local bathymetry characteristics and inhomogeneous net heat flux due to the latitude difference are the major cause for the early formation of the ADCCBW. Numerical Lagrangian drifter experiments support the finding that the ADCCBW is maintained throughout the stratification periods by the inflow of cold bottom water from the northern Yellow Sea and deep channel in the western side of Liaodong Peninsula. The inflow cold water contributes to the north depression basin distinctively larger than to the south one. Tidal mixing enhances the bottom temperature asymmetry between the two basins.

  20. Horns Rev offshore wind farm. Environmental impact assessment of sea bottom and marine biology

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.

    2000-03-15

    An Environmental Impact Assessment (EIA) of a planned 150 MW offshore wind farm at Horns Rev has been carried out for the marine biology and sea bottom in the area, and includes vegetation and benthic fauna. The study forms part of a total EIA of the planned offshore wind farm. This EIA study has been drawn up in accordance with the guidelines laid down by the Ministry of Environment and Energy in the publication, 'Guidelines for preparation of EIAstudies for offshore wind farms. Horns Rev is situated off Blaevands Huk, which is Denmark's most westerly point. It is a shallow reef with water depths between 2 and 9 metres and is primarily composed of sand, gravel and pebbles. The area designated for the wind farm lies directly south of Horns Rev and is dominated by sand with a median particle size of 0.3 mm. Along the edges, towards areas of greater depth, the particle size increases. There are areas of fine sand in the deepest area, and in isolated pockets within the proposed wind farm site. The sediment is characterised by a very low (<1%) organic matter content. On the basis of the expected impact from the establishment of the wind farm, it is not deemed necessary to carry out special programmes during the construction phase for monitoring of the environmental-biological conditions. A monitoring and control programme is recommended during the production phase in order to follow the copper concentration in bivalves, or alternatively to initiate recovery or elimination of the copper-laden waste. A control programme is recommended during the production phase in order to follow the establishment and succession of the fouling community on the wind turbine foundations and scour-protecting revetments. (BA)

  1. Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health

    Directory of Open Access Journals (Sweden)

    N. Greenwood

    2009-08-01

    Full Text Available This paper presents new results from high temporal resolution observations over two years (2007 and 2008 from instrumented moorings deployed in the central North Sea, at the Oyster Grounds and on the northern slope of Dogger Bank (North Dogger. The water column was stratified in the summer at both sites, leading to limited exchange of the water in the bottom mixed layer. Data from these moorings revealed the variable nature of summer oxygen depletion at the Oyster Grounds. The combination of in situ and ship-based measurements allowed the physical and biological conditions leading to decreasing dissolved oxygen concentrations in bottom water to be examined. The concentration of dissolved oxygen in the bottom water at both sites was observed to decrease throughout the summer period after the onset of stratification. Depleted dissolved oxygen concentration (6.5 mg l−1, 71% saturation was measured at the North Dogger, a site which is not significantly influenced by anthropogenic nutrient inputs. Lower oxygen saturation (5.2 mg l−1, 60% saturation was measured for short durations at the Oyster Grounds. Increasing bottom water temperature accounted for 55% of the decrease in dissolved oxygen concentration at the Oyster Grounds compared to 10% at North Dogger.

    Dissolved oxygen concentration in bottom water at the Oyster Grounds was shown to be strongly influenced by short term events including storm events and pulses of biomass input. In contrast, dissolved oxygen concentration in bottom water at the North Dogger reflected longer seasonal processes such as gradual temperature increases and a more steady supply of biomass to the bottom mixed layer. The differences between the study sites shows the need for an improved understanding of the mechanisms driving these processes if the use of oxygen in marine management and ensuring ecosystem health is to be meaningful and successful in the future. These observations

  2. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental...

  3. Influence of Stream Bottom Substrate on Retention and Transport of Vertebrate Environmental DNA.

    Science.gov (United States)

    Jerde, Christopher L; Olds, Brett P; Shogren, Arial J; Andruszkiewicz, Elizabeth A; Mahon, Andrew R; Bolster, Diogo; Tank, Jennifer L

    2016-08-16

    While environmental DNA (eDNA) is now being regularly used to detect rare and elusive species, detection in lotic environments comes with a caveat: The species being detected is likely some distance upstream from the point of sampling. Here, we conduct a series of seminatural stream experiments to test the sensitivity of new digital droplet PCR (ddPCR) to detect low concentrations of eDNA in a lotic system, measure the residence time of eDNA compared to a conservative tracer, and we model the transport of eDNA in this system. We found that while ddPCR improves our sensitivity of detection, the residence time and transport of eDNA does not follow the same dynamics as the conservative tracer and necessitates a more stochastic framework for modeling eDNA transport. There was no evidence for differences in the transport of eDNA due to substrate type. The relatively large amount of unexplained variability in eDNA transport reveals the need for uncovering mechanisms and processes by which eDNA is transported downstream leading to species detections, particularly when inferences are to be made in natural systems where eDNA is being used for conservation management. PMID:27409250

  4. The atomic details of the interfacial interaction between the bottom electrode of Al/AlOx/Al Josephson junctions and HF-treated Si substrates

    Science.gov (United States)

    Zeng, L. J.; Krantz, P.; Nik, S.; Delsing, P.; Olsson, E.

    2015-04-01

    The interface between the Al bottom contact layer and Si substrates in Al based Josephson junctions is believed to have a significant effect on the noise observed in Al based superconducting devices. We have studied the atomic structure of it by transmission electron microscopy. An amorphous layer with a thickness of ˜5 nm was found between the bottom Al electrode and HF-treated Si substrate. It results from intermixing between Al, Si, and O. We also studied the chemical bonding states among the different species using energy loss near edge structure. The observations are of importance for the understanding of the origin of decoherence mechanisms in qubits based on these junctions.

  5. The influence of climate change on the intensity of ice gouging at the Kara Sea bottom by hummocky formations

    Science.gov (United States)

    Ogorodov, Stanislav; Arkhipov, Vasily; Kokin, Osip; Natalia, Shabanova

    2016-04-01

    Sea ice as a zonal factor is an important passive and active relief-forming agent in the coastal-shelf zone of the Arctic and other freezing seas. The most dangerous process in relation to the hydrotechnical facilities is ice gouging - destructive mechanical impact of the ice of the ground, connected with the dynamics of the ice cover, formation of hummocks and stamukhas under the influence of hydrometeorologic factors and of the relief of the coastal-shelf zone. Underestimation of the ice gouging intensity can lead to damage of the engineering facilities, while excessive deepening increases the expenses of the construction. Finding the optimal variant and, by this, decreasing the risks of extreme situations is a relevant task of the science and practice. This task is complicated by the fact that the oil and gas infrastructure within the coastal and shelf areas of the freezing seas is currently being developed in the conditions of global climate change. In the present work, several results of the repeated sounding of bottom ice gouging microrelief within the area of the underwater pipeline crossing of the Baydaratskaya Bay, Kara Sea, are presented. Based on the results of the monitoring, as well as the analysis of literature sources and modeling it has been established that under the conditions of climate warming and sea ice reduction, the zone of the most intensive ice gouging is shifted landwards, on shallower water areas.

  6. Contribution of the Yellow Sea bottom cold water to the abnormal cooling of sea surface temperature in the summer of 2011

    Science.gov (United States)

    Lee, Joon-ho; Pang, Ig-Chan; Moon, Jae-Hong

    2016-06-01

    Satellite-based sea surface temperature (SST) measurements revealed an abnormal cooling anomaly over the Yellow Sea (YS) in the summer of 2011. Using in situ hydrographic profiles, meteorological fields, and an ocean circulation model with a passive tracer experiment, we identified the cold SST anomaly and its connection with the YS Bottom Cold Water (YSBCW), which occupies the central part of the YS below the thermocline in the summer. The summer SST anomalies in the YS showed three cold peaks in 1993, 2003, and 2011 over the past 20 years, but the reasons for the cooling events were different, as one was due to weakened surface heating and the other was attributed to mixing with the YSBCW. In 1993 and 2003, relatively weak surface heating made the surface water cooler compared with that during the other years, whereas in 2011, a strong vertical mixing of water was induced by a typhoon that passed through the central YS, causing the surface water to cool by ˜8°C and the bottom water to warm up by ˜4°C. A tracer experiment further confirmed that the vertical heat transfers between the warm surface and the cold bottom water masses when the typhoon passed through the YS interior.

  7. Benthic O2 exchange across hard-bottom substrates quantified by eddy correlation in a sub-Arctic fjord

    DEFF Research Database (Denmark)

    Glud, Ronnie N.; Berg, Peter; Hume, Andrew;

    2010-01-01

    Oxygen exchange across the seabed is a key measure for quantifying benthic carbon turnover. However, technical limitations have restricted such measurements to sedimentary areas. Few assessments on hard-bottom substrates exist although such biotopes are frequent along many coastlines. In spring...

  8. Benthic O2 exchange across hard-bottom substrates quantified by eddy correlation in a sub-Arctic fjord

    DEFF Research Database (Denmark)

    Glud, Ronnie N.; Berg, Peter; Hume, Andrew;

    2010-01-01

    Oxygen exchange across the seabed is a key measure for quantifying benthic carbon turnover. However, technical limitations have restricted such measurements to sedimentary areas. Few assessments on hard-bottom substrates exist although such biotopes are frequent along many coastlines. In spring...

  9. Coastal polynyas in the southwestern Weddell Sea: ice production and bottom water formation

    OpenAIRE

    Haid, Verena; Timmermann, Ralph; Ebner, Lars; Heinemann, Günther

    2011-01-01

    Coastal polynyas are areas in the ice-covered ocean from which the sea-ice cover has been mechanically removed, primarily by winds. They are areas of enhanced exchange processes between ocean and atmosphere. The increased heat flux allows for exceptionally high freezing rates, which lead to locally increased brine-rejection. In the southwestern Weddell Sea, wide continental shelves and a weak exchange with the open ocean provide conditions that allow for substantial salinity enrichment, formi...

  10. Electromagnetic fields at the sea bottom induced by a line of immersed electric dipoles

    OpenAIRE

    Edson E.S. Sampaio

    2011-01-01

    The analysis of electromagnetic fields caused by alternate or transient electric currents flowing along a cable in sea water has several applications. It supports the interpretation of electromagnetic geophysical data and safety procedures against the threat of sea mines. The approach to the problem employs a magnetic vector potential in the frequency domain due to a pulse source electric dipole, and performs Laplace and Hankel transforms and integration along the cable, to describe the varia...

  11. A near-uniform fluctuation of ocean bottom pressure and sea level across the deep ocean basins of the Arctic Ocean and the Nordic Seas

    Science.gov (United States)

    Fukumori, Ichiro; Wang, Ou; Llovel, William; Fenty, Ian; Forget, Gael

    2015-05-01

    Across the Arctic Ocean and the Nordic Seas, a basin-wide mode of ocean bottom pressure and sea level fluctuation is identified using satellite and in situ observations in conjunction with a global ocean circulation model and its adjoint. The variation extends across the interconnected deep ocean basins of these semi-enclosed Arctic seas, collectively called the Arctic Mediterranean, with spatially near-uniform amplitude and phase. The basin-wide fluctuation is barotropic and dominates the region's large-scale variability from sub-monthly to interannual timescales. The fluctuation results from bifurcating coastally trapped waves generated by winds along the continental slopes of the Arctic Mediterranean and its neighboring seas, including the North Atlantic Ocean. The winds drive Ekman transport across the large bathymetric gradients, forcing mass divergence between the shallow coastal area and the deep ocean basins and creating ocean bottom pressure anomalies of opposite signs in the two regions. The anomalies rapidly propagate away as barotropic coastally trapped waves with the coast and continental slope as respective boundaries. The waves subsequently bifurcate at the shallow straits connecting the Arctic Mediterranean with the rest of the globe. The straits transmit the shallow anomalies but not the deep variations, thereby inhibiting the anomalies' mutual cancelation by geographically separating the two. Anomalies that enter the deep Arctic basins equilibrate uniformly across the domain characterized by a homogeneous depth-integrated planetary potential vorticity distribution. The potential vorticity's steep gradient that borders the basins shields the region from neighboring shallow variations, giving rise to the observed spatially confined fluctuation. Compensating anomalies outside the Arctic adjust similarly across the rest of the globe but are comparatively negligible in amplitude because of the global ocean's larger area relative to that of the deep

  12. Seafloor slow vertical displacement inferred by sea bottom pressure measurements in shallow water: an application to the Campi Flegrei volcanic area

    Science.gov (United States)

    Chierici, Francesco; Pignagnoli, Luca; Iannaccone, Giovanni; Guardato, Sergio; Locritani, Marina; Embriaco, Davide; Donnarumma, Gian Paolo; La Rocca, Adriano; Pinto, Salvatore; Beranzoli, Laura

    2016-04-01

    The vertical component of sea floor displacement in tectonic or volcanically active areas can be observed using sea bottom pressure recorders. These measurements are usually acquired in areas affected by strong dynamics with large vertical displacement and in deep water, where the noise induced by the sea state is low. Under these conditions the contribution of the variation of sea water density and the contribution of the instrumental drift - a typical feature of the bottom pressure recorders - can be negligible. We have developed a new methodology to monitor vertical sea floor displacement both in areas with small and slow deformation, and in shallow water. We take advantage of bottom pressure recorder data, augmented with ancillary sea level, barometric and water physical parameters measurements. We have applied this method to the data collected by a bottom pressure recorder deployed at 100 m w.d. in the Campi Flegrei Caldera as part of CUMAS multiparameter monitoring system. During several months of 2011 we have observed a small uplift episode related to the bradiseismic activity of the area. These observations are compatible with other geodetic data recorded in the region and provide unprecedented measurements of the vertical deformation in the marine area.

  13. The trade-off of light trapping between top and bottom cell in micromorph tandem solar cells with sputtering ZnO:Al glass substrate

    Science.gov (United States)

    Bai, Lisha; Liu, Bofei; Fan, Jun; Zhang, Dekun; Wei, Changchun; Sun, Jian; Zhao, Ying; Zhang, Xiaodan

    2014-11-01

    A simulated and experimental investigation of the trade-off between light trapping and current matching in p-i-n structured a-Si:H/μc-Si:H tandem solar cells is presented, which aims to address the limited short circuit current density (Jsc) that results from the low long-wavelength light scattering of the fluorine-doped tin oxide (SnO2:F) substrates typically used. To this end, the mismatch of the Jsc between the top and bottom cells is reduced by utilizing a ZnO:Al substrate with optimized long-wavelength light scattering properties as the front contact, thereby improving the response of the bottom cell at the expense of the lower top cell's Jsc yet. A trade-off between the top and bottom cell's light response is subsequently found with SnO2 or ZnO:Al as a substrate, by introducing an n-type μc-SiOx intermediate reflector (IR) between the two component cells. An initial efficiency based on an approximate current matching of 11.90% is achieved for a-Si:H/μc-Si:H tandem solar cell by adopting a magnetron-sputtered and texture-etched ZnO:Al substrate and an optimized n-type μc-SiOx IR.

  14. Late quaternary sea bottom conditions in the southern Panama basin, Eastern Equatorial Pacific

    Science.gov (United States)

    Patarroyo, German D.; Martínez, José I.

    2015-11-01

    A paleoceanographic reconstruction of the southern Panama Basin for the last 23.000 years, based on the benthic foraminiferal analysis from the deep sea core ME0005A-24JC (0.01°N, 86.28°W, water depth 2941) is presented. Cluster and SHEBI (SHE Analysis for Biozone Identification) analyses performed on the benthic foraminiferal assemblages, evidence a faunal turnover in the early Holocene at 14 ky BP. Between 23 and 14 ky BP, Fursenkoina rotundata, Hoeglundina elegans, Globobulimina affinis, Globobulimina pacifica, Cibicidoides wuellerstorfi and Uvigerina hispidocostata were common. Conversely, from 14 ky to the present, the assemblage is represented by Chilostomella oolina, Laticarinina pauperata, and Uvigerina proboscidea. This faunal turnover suggests significant fluctuations in oxygen content at the sea floor and the organic matter (OM) influx, which could reflect: (1) fluctuations in the surface productivity related to the equatorial divergence and, (2) OM advection caused by the dynamic of the deep sea currents. Paleoproductivity estimates and benthic foraminiferal rates depict a general trend towards lower values since the Last Glacial Maximum (LGM) with a conspicuous change at 14 ky BP. Therefore, the paleoceanographic reconstructions of the ME0005A-24JC core suggest a transition from La Niña-like conditions during the LGM to El Niño-like conditions in the recent, as previously proposed for the Eastern Equatorial Pacific. Estimates of the paleo-intensity of deep sea currents based on the relative percentage abundance of the epifaunal foraminifera Cibicidoides wuellerstorfi suggest stronger deep sea currents on the Carnegie Ridge before 14 ky BP.

  15. Water-scattered signal to compensate for the rough sea surface effect on bottom lidar imaging.

    Science.gov (United States)

    Dolin, Lev S; Luchinin, Alexander G

    2008-12-20

    We investigate the possibility of using the water-backscattered radiation from a bottom sounding airborne imaging light detection and ranging (lidar) system to determine the surface slope at the point where the laser beam intersects the surface. We show that the refraction angle of the beam can be determined using receivers whose sensitivities vary linearly over their field of view. Equations are derived to estimate the statistical mean and variance values of this refracted angle. We demonstrate that the proposed algorithm improves lidar imaging. Numerical examples with reference to typical marine conditions are given. PMID:19104538

  16. [A study of dissolved oxygen flux across the water-bottom interface in the northeastern Black Sea (in the region of Dzhubga village)].

    Science.gov (United States)

    Vershinin, A V; Korneeva, G A; Pautova, L N; Sapozhnikov, F V

    2008-01-01

    Oxygen exchange at the water-bottom interface in the northeastern Black Sea was studied using bottom tanks (fluxes and oxygen consumption for organic matter mineralization and for respiration of soil and water organisms). The relationship of biogenic fluxes and patterns of biochemical (enzyme) destruction of organic matter by the components of the bacterial and microproducer community was established. The prevalence of microbial oxidation of organic matter correlated with high proteolytic activity in near-bottom water. The principal significance of organic matter oxidation in near-bottom water for the phytoplankton and its respiratory expenditures was demonstrated both in the open system of the near-bottom layer and in the closed tank system. A similar trend was demonstrated for benthic organisms. PMID:18491566

  17. The atomic details of the interfacial interaction between the bottom electrode of Al/AlO{sub x}/Al Josephson junctions and HF-treated Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, L. J.; Nik, S.; Olsson, E. [Department of Applied Physics, Chalmers University of Technology, 412 96 Gothenburg (Sweden); Krantz, P.; Delsing, P. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg (Sweden)

    2015-04-28

    The interface between the Al bottom contact layer and Si substrates in Al based Josephson junctions is believed to have a significant effect on the noise observed in Al based superconducting devices. We have studied the atomic structure of it by transmission electron microscopy. An amorphous layer with a thickness of ∼5 nm was found between the bottom Al electrode and HF-treated Si substrate. It results from intermixing between Al, Si, and O. We also studied the chemical bonding states among the different species using energy loss near edge structure. The observations are of importance for the understanding of the origin of decoherence mechanisms in qubits based on these junctions.

  18. Orbital and suborbital variability in North Atlantic bottom water temperature obtained from deep-sea ostracod Mg/Ca ratios

    Science.gov (United States)

    Cronin, T. M.; Dwyer, G.S.; Baker, P.A.; Rodriguez-Lazaro, J.; DeMartino, D.M.

    2000-01-01

    Magnesium/calcium (Mg/Ca) ratios were measured in the deep-sea ostracod (Crustacea) genus Krithe from Chain core 82-24-4PC from the western mid-Atlantic Ridge (3427 m) in order to estimate ocean circulation and bottom water temperature (BWT) variability over the past 200,000 years. Mg/Ca ratios have been used as a paleothermometer because the ratios are controlled primarily by ambient water temperatures at the time the organism secretes its adult carapace. Over the past two glacial-interglacial cycles, Mg/Ca values oscillated between about 7 mmol/mol and 12 mmol/mol, equivalent to a BWT range of 0 to > 3.5??C. The lowest values were obtained on specimens from glacial marine isotope stages (MISs) 2, 4 and 6; the highest values were obtained from specimens from the early part of the Holocene interglacial (MIS 1), and also from MISs 5 and 7. These trends suggest that BWTs in the North Atlantic Ocean fluctuate over orbital time scales. Suborbital variability in Mg/Ca ratios and BWT was also observed for the past 100,000 years. Ratios rose from ~8 mmol/mol to ~10 mmol/mol (implying a BWT increase of ~1 to 3??C) during 14 Mg/Ca excursions. The highest ratios were found in Krithe dated at approximately 32, 36-38, 43, 48, 73, 85 and 93 ka. Although the age model for the Chain 82-24-4PC and temporal resolution do not allow precise correlation, some of these deep-sea bottom temperature excursions appear to correspond to Heinrich events recorded in other regions of the North Atlantic and perhaps Dansgaard-Oeschger interstadial events recorded in Greenland ice cores. If confirmed, this would support the hypothesis that millennial-scale oscillations of climate in the North Atlantic are capable of affecting global climate via thermohaline circulation changes. (C) 2000 Elsevier Science B.V.

  19. Clay minerals and geochemistry of the bottom sediments in the northwestern East China Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite (>68%) is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea (SCS). Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe (Yellow) River. The relatively high abundant kaolinite is likely derived from the Changjiang (Yangtze) River via the Taiwan Warm Current. In contrast,large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River's submerged delta have much lower 87Sr/86Sr ratios (0.7162-0.7180) than those of the Shandong Peninsular mud wedge (0.7216-0.7249),which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang

  20. Impact of bottom trawling on deep-sea sediment properties along the flanks of a submarine canyon.

    Directory of Open Access Journals (Sweden)

    Jacobo Martín

    Full Text Available The offshore displacement of commercial bottom trawling has raised concerns about the impact of this destructive fishing practice on the deep seafloor, which is in general characterized by lower resilience than shallow water regions. This study focuses on the flanks of La Fonera (or Palamós submarine canyon in the Northwestern Mediterranean, where an intensive bottom trawl fishery has been active during several decades in the 400-800 m depth range. To explore the degree of alteration of surface sediments (0-50 cm depth caused by this industrial activity, fishing grounds and control (untrawled sites were sampled along the canyon flanks with an interface multicorer. Sediment cores were analyzed to obtain vertical profiles of sediment grain-size, dry bulk density, organic carbon content and concentration of the radionuclide 210Pb. At control sites, surface sediments presented sedimentological characteristics typical of slope depositional systems, including a topmost unit of unconsolidated and bioturbated material overlying sediments progressively compacted with depth, with consistently high 210Pb inventories and exponential decaying profiles of 210Pb concentrations. Sediment accumulation rates at these untrawled sites ranged from 0.3 to 1.0 cm y-1. Sediment properties at most trawled sites departed from control sites and the sampled cores were characterized by denser sediments with lower 210Pb surface concentrations and inventories that indicate widespread erosion of recent sediments caused by trawling gears. Other alterations of the physical sediment properties, including thorough mixing or grain-size sorting, as well as organic carbon impoverishment, were also visible at trawled sites. This work contributes to the growing realization of the capacity of bottom trawling to alter the physical properties of surface sediments and affect the seafloor integrity over large spatial scales of the deep-sea.

  1. Evidence of prolonged aragonite undersaturations in the bottom waters of the southern Bering Sea shelf from autonomous sensors

    Science.gov (United States)

    Mathis, Jeremy T.; Cross, Jessica N.; Monacci, Natalie; Feely, Richard A.; Stabeno, Phyllis

    2014-11-01

    The southeastern shelf of the Bering Sea is a dynamic area that experiences seasonal variability in primary production and remineralization of organic matter, both of which control the carbon biogeochemistry of the water column. Surface-water partial pressure of carbon dioxide (pCO2) is greatly reduced in summer by biological production, which increases carbonate mineral saturation states (Ω). In contrast, the export of large quantities of organic matter from surface blooms drives an active remineralization loop that sharply increases pCO2 near the bottom, lowering pH and suppressing Ω. New observations from moored biogeochemical sensors in 2011 showed that seasonal net community production lowers surface-water pCO2, causing large gradients between the ocean and atmosphere that are sustained throughout the summer, confirming that these waters likely remain supersaturated with respect to aragonite throughout the open water season. On the other hand, moored sensors deployed near the bottom showed that pCO2 levels exceed 500 μatm by early June and remain at these high levels well into the autumn months, indicating that the bottom waters are likely continuously undersaturated in aragonite for at least several months during each year. Only a small fraction of the increased pCO2 can currently be attributed to the intrusion of anthropogenic CO2 from the atmosphere, while the majority is due to natural respiration processes. The biological impacts, along with the timing and duration of these undersaturation events, could play a role in the development of larval and juvenile calcifiers in the region and will change as anthropogenic CO2 concentrations continue to rise.

  2. An Assessment of Metals (Pb and Cu Contamination in Bottom Sediment from South China Sea Coastal Waters, Malaysia

    Directory of Open Access Journals (Sweden)

    M. C. Ong

    2009-01-01

    Full Text Available Problem statement: The accumulation of metal contaminants in sediments can pose serious environmental problems to the surrounding areas. Trace metal contamination in sediment could affect the water quality and the bio-assimilation and bioaccumulation of metals in aquatic organisms, resulting in potential long-term implications on human health and ecosystem. Approach: About 154 bottom sediment samples were collected using Smith McIntyre in a transect pattern from South China Sea East Coast coastal water (Terengganu, Pahang and Johor coastal area. The study focused on the levels of Pb and Cu in order to assess the extent of environment pollution and to discuss the origin of these contaminants in the sediment. Results: Results showed that the average concentration of Pb and Cu was 33.70 µg g-1 dry weights and 22.40 µg g-1 dry weights, respectively. Pb and Cu have relatively lower Enrichment Factors (EF value and geo-accumulation (Igeo indices in study area and these analysis validated that elevated heavy metals concentration in most sample are not due to artificial contamination. Conclusion: Overall, geochemistry of the samples showed the effect of both natural and anthropogenic inputs to the catchment, however, natural processes were more dominant than anthropogenic inputs in concentrating metals. Results obtained would help to develop strategies for pollution control and sediment remediation of coastal waters in the South China Sea.

  3. Modelling flow in the porous bottom of the Barents Sea shelf

    Directory of Open Access Journals (Sweden)

    Stanisław R. Massel

    2013-02-01

    Full Text Available In their recent paper, Węsławski et al. (2012 showed that theSvalbardbanken area of the Barents Sea is characterized by a high organiccarbon settlement to the permeable sea bed, which consists of gravel andshell fragments of glacial origin.In the present paper, which can be considered as a supplement to the Węsławskiet al. paper, two potential hydrodynamic mechanisms of downwardpore water transport into porous media are discussed in detail.In particular, estimated statistical characteristics of the pore waterflow, induced by storm surface waves, indicate that the dischargeof water flow can be substantial, even at large water depths.During stormy weather (wind velocity V=15 m s-1 and windfetch X =200 km as much as 117.2 and 26.1 m3 hour-1 ofwater filter through the upper 5 m of the shell pit at waterdepths of 30 and 50 m respectively. For a porous layer ofgreater thickness, the mean flow discharge is even bigger.     The second possible mechanism of flow penetration in the porous layeris based on the concept of geostrophic flow and spiral formation withinthe Ekman layer. Assuming that the current velocity in the near-bottomwater layer is ū = 1 m, the resulting mean dischargethrough this layer becomes as large as 0.99 and 0.09 m3 s-1for downstream and transverse flows respectively.

  4. The state control of radioecological danger of the sunken and scuttled nuclear objects on the sea bottom in Russian Federation

    International Nuclear Information System (INIS)

    At the bottom of World ocean there is the significant number of underwater potentially dangerous objects (PDO): nuclear submarines; diesel submarines with nuclear weapon; solid radioactive waste; chemical weapon; petroleum and gas pipelines (including perspective); sunken ships with petroleum and other dangerous loads. For nuclear objects is developed a model for estimating the radioecological consequences of the release of radionuclides to the marine environment. The model is practically used at fulfilment of the program of researches on the sunken nuclear submarine Komsomolets'. Under orders of Ministry of extreme situations of Russia the experts from naval research institutes have carried out the analysis and expert estimation of potentially dangerous objects, being at the sea bottom and belonging to Russian Federation. The first turn of a databank about PDO is created. Classification of PDO on a degree of danger on three categories is developed: 1-(extremely dangerous), 11-(highly dangerous), 111-(middle dangerous). Offers on priorities of work on underwater potentially dangerous objects are reasonable. Is shown, that forwarding inspections of places of probable radioactive pollution in the Arctic seas and places of wreck of nuclear submarines 'K-8'(1960), 'K-219'(1986), 'K-27'(1968) are first of all expedient. Received data have allowed to prove necessity of development of the federal law about safety underwater potentially dangerous objects in the seas, international agreements concerning the control for similar objects. Is reasonable is necessary development the bills of Government of Russian Federation, in particular about the status about declaration of safety of underwater potentially dangerous objects and about the responsibility for these objects. The Ministry of extreme situations of Russia in 1999 has organized special commission with the representatives of all interested ministries for development of the coordinated approach to creation of the state

  5. Decline of deep and bottom water ventilation and slowing down of anthropogenic carbon storage in the Weddell Sea, 1984-2011

    NARCIS (Netherlands)

    Huhn, Oliver; Rhein, Monika; Hoppema, Mario; van Heuven, Steven

    2013-01-01

    We use a 27 year long time series of repeated transient tracer observations to investigate the evolution of the ventilation time scales and the related content of anthropogenic carbon (C-ant) in deep and bottom water in the Weddell Sea. This time series consists of chlorofluorocarbon (CFC) observati

  6. Distribution of dissolved and labile particulate trace metals in the overlying bottom water in the Vistula River plume (southern Baltic Sea)

    NARCIS (Netherlands)

    Sokolowski, A.; Wolowicz, M.; Hummel, H.

    2001-01-01

    Overlying bottom water samples were collected in the Vistula River plume, southern Baltic Sea, (Poland) and analysed for dissolved and labile particulate (1 M HCl extractable) Cu, Pb, Zn, Mn, Fe and Ni, hydrological parameters being measured simultaneously. Particulate organic matter (POM), chloroph

  7. Bottom-up synthesis of ordered metal/oxide/metal nanodots on substrates for nanoscale resistive switching memory

    Science.gov (United States)

    Han, Un-Bin; Lee, Jang-Sik

    2016-05-01

    The bottom-up approach using self-assembled materials/processes is thought to be a promising solution for next-generation device fabrication, but it is often found to be not feasible for use in real device fabrication. Here, we report a feasible and versatile way to fabricate high-density, nanoscale memory devices by direct bottom-up filling of memory elements. An ordered array of metal/oxide/metal (copper/copper oxide/copper) nanodots was synthesized with a uniform size and thickness defined by self-organized nanotemplate mask by sequential electrochemical deposition (ECD) of each layer. The fabricated memory devices showed bipolar resistive switching behaviors confirmed by conductive atomic force microscopy. This study demonstrates that ECD with bottom-up growth has great potential to fabricate high-density nanoelectronic devices beyond the scaling limit of top-down device fabrication processes.

  8. Bottom-up synthesis of ordered metal/oxide/metal nanodots on substrates for nanoscale resistive switching memory

    Science.gov (United States)

    Han, Un-Bin; Lee, Jang-Sik

    2016-01-01

    The bottom-up approach using self-assembled materials/processes is thought to be a promising solution for next-generation device fabrication, but it is often found to be not feasible for use in real device fabrication. Here, we report a feasible and versatile way to fabricate high-density, nanoscale memory devices by direct bottom-up filling of memory elements. An ordered array of metal/oxide/metal (copper/copper oxide/copper) nanodots was synthesized with a uniform size and thickness defined by self-organized nanotemplate mask by sequential electrochemical deposition (ECD) of each layer. The fabricated memory devices showed bipolar resistive switching behaviors confirmed by conductive atomic force microscopy. This study demonstrates that ECD with bottom-up growth has great potential to fabricate high-density nanoelectronic devices beyond the scaling limit of top-down device fabrication processes. PMID:27157385

  9. DRIVERS OF THE DYNAMICS OF DIAZOTROPHS AND DENITRIFIERS IN NORTH SEA BOTTOM WATERS AND SEDIMENTS

    Directory of Open Access Journals (Sweden)

    Lucas eStal

    2015-07-01

    Full Text Available The fixation of dinitrogen (N2 and denitrification are two opposite processes in the nitrogen cycle. The former transfers atmospheric dinitrogen gas into bound nitrogen in the biosphere, while the latter returns this bound nitrogen back to atmospheric dinitrogen. It is unclear whether or not these processes are intimately connected in any microbial ecosystem or that they are spatially and/or temporally separated. Here, we measured seafloor nitrogen fixation and denitrification as well as pelagic nitrogen fixation by using the stable isotope technique. Alongside, we measured the diversity, abundance, and activity of nitrogen-fixing and denitrifying microorganisms at three stations in the southern North Sea. Nitrogen fixation ranged from undetectable to 2.4 nmol N L-1 d-1 and from undetectable to 8.2 nmol N g-1 d-1 in the water column and seafloor, respectively. The highest rates were measured in August at Doggersbank, both for the water column and for the seafloor. Denitrification ranged from 1.7 to 208.8 µmol m-2 d-1 and the highest rates were measured in May at the Oyster Grounds. DNA sequence analysis showed sequences of nifH, a structural gene for nitrogenase, related to sequences from anaerobic sulfur/iron reducers and sulfate reducers. Sequences of the structural gene for nitrite reductase, nirS, were related to environmental clones from marine sediments. Quantitative polymerase chain reaction (qPCR data revealed the highest abundance of nifH and nirS genes at the Oyster Grounds. Quantitative reverse transcription polymerase chain reaction (qRT-PCR data revealed the highest nifH expression at Doggersbank and the highest nirS expression at the Oyster Grounds. The distribution of the diazotrophic and denitrifying communities seems to be subject to different selecting factors, leading to spatial and temporal separation of nitrogen fixation and denitrification. These selecting factors include temperature, organic matter availability, and

  10. Seabed substrates and sedimentation rates of the European Seas - EMODnet-Geology2

    Science.gov (United States)

    Kaskela, Anu; Kotilainen, Aarno; Alanen, Ulla; Stevenson, Alan; Partners, EMODnet Geology 2

    2015-04-01

    Seas and oceans are important for us. However, increased human activities in marine and coastal areas have altered marine ecosystems worldwide. To ensure sustainable use of marine resources and health of the seas, improved management is needed. The European Union's (EU) Marine Strategy Framework Directive targets to achieve Good Environmental Status (GES) of the EU's marine waters by 2020. However, it has been acknowledged that the poor access to data on the marine environment was a handicap to government decision-making, a barrier to scientific understanding and a break on the economy. The effective management of the broad marine areas requires spatial datasets covering all European marine areas. As a consequence the European Commission adopted the European Marine Observation and Data Network (EMODnet) in 2009 to combine dispersed marine data into publicly available datasets covering broad areas. The second phase of the EMODnet -Geology project started in 2013 and it will run for 3 years. The partnership includes 36 marine organizations from 30 countries. The partners, mainly from the marine departments of the geological surveys of Europe (through the Association of European Geological Surveys - EuroGeoSurveys), aim to assemble marine geological information at a scale of 1:250,000 from all European sea areas (e.g. the White Sea, Baltic Sea, Barents Sea, the Iberian Coast, and the Mediterranean Sea within EU waters). In comparison to the urEMODnet project (2009-2012) the data will be more detailed and aim to cover much larger area. The project includes collecting and harmonizing the first seabed substrate map for the European Seas, as well as data/map showing sedimentation rates at the seabed. The data will be essential not only for geologists but also for others interested in marine sediments like marine managers and habitat mappers. A 1:250,000 GIS layer on seabed substrates will be delivered in the portal, in addition to the existing 1:1 million map layer from

  11. The submarine hydrothermal system of Panarea (Southern Italy: biogeochemical processes at the thermal fluids - sea bottom interface

    Directory of Open Access Journals (Sweden)

    T. Maugeri

    2006-06-01

    Full Text Available Among the submarine hydrothermal systems located offshore the volcanic archipelago of the Aeolian Islands (Southern Italy, the most active is located off the coasts of Panarea island. Thermal waters, gases and sulfur deposits coexist at the sea bottom where hydrothermal fluids are released from both shallow and deep vents. The chemical and isotopic composition of the fluid phase shows the presence of a significant magmatic component and the physico-chemical conditions of the geothermal reservoir allow the release of reduced chemical species that are microbially mediated towards the production of organic carbon as a form of biochemical energy. Microorganisms inhabiting this environment possess nutritional requirements and overall metabolic pathways ideally suited to such ecosystem that represents a clear example of the close connection between geosphere and biosphere. Microscopic examination of the white mat attached to rock surfaces showed the presence of Thiothrix-like filamentous bacteria. Moderately thermophilic heterotrophic isolates were identified as strains of the genus Bacillus. Although the hydrothermal system of Panarea has to be considered a “shallow” system, it shows many characteristics that make it similar to the “deep” oceanic systems, giving a unique opportunity for improving our knowledge on such an unexplored world by working at this easily accessible site.

  12. Simulation of meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

    Institute of Scientific and Technical Information of China (English)

    WANG Dongxiao; LIU Xiongbin; WANG Wenzhi; DU Yan; ZHOU Weidong

    2004-01-01

    The large-scale upper circulations and meridional overturning in the upper layer of the South China Sea (SCS) with idealized bottom topography in winter and summer are investigated. Simulations with the GFDL general circulation model are carried out under the conditions of open or enclosed boundary regarding transport in the Luzon Strait. The intrusion area of Kuroshio, its impact on the meridional overturning in the upper layer of the SCS and seasonal characteristic of this impact are explored, respectively. The model is forced by climatological wind stress and relaxed to monthly mean climatological temperature and salinity. The resultant meridional overturning is non-enclosed, with transporting from north to south in the surface and returning to north at the depth of about 500 m in winter, about 200 m in summer, with amplitudes of 105 m3/s. It shows the transporting path of intermediate water of the SCS and offers an idealized reference for further study on dynamics of wind-driven and thermohaline circulation of the SCS.

  13. Geochemical monitoring of the bottom sediments of the Barents Sea - exogenous and endogenous sources of polyaromatic hydrocarbons.

    Science.gov (United States)

    Petrova, Vera I.; Kursheva, Anna; Litvinenko, Ivan; Morgunova, Inna

    2016-04-01

    Detailed organic geochemical study of the immersed bottom sediments of the Northern and North-Western parts of the Barents Sea region indicated the significant difference in the group and molecular composition of the dispersed organic matter (DOM). Hydrocarbons (HCs) distribution anomalies were identified in the western part of the Svalbard Island shelf, the area around the Shtokman gas condensate field and the Kola-Kanin Monocline shelf zone. The studied sediments (9 cores, up to 2 m length) were collected during scientific research cruises of "VNIIOkeangeology named after I.S. Gramberg" (Saint-Petersburg, Russia) to the Barents Sea between 1992-2006. Analytical procedure included the determination of elementary (TOC, Ccarb), group and molecular composition of DOM soluble part using preparative liquid chromatography and GC-MS analysis with the Agilent Technologies 6850/5973 GC System. The studied samples are generally represented by low carbonate homogeneous pelites and aleuropelites (Ccarb≤0.8% in sed.). The total organic carbon slightly varies through the sediment section and regularly decreases with depth, not exceeding 2% in the upper layer of sediments for the region. The maximum of chloroform bitumoid "a" was detected in the Svalbard shelf area (up to 0.04% in sed.). The molecular composition and ratio of PAHs in the Svalbard samples points to the high level of OM transformation (MPI1≥0.6), that along with the lack of biogenic structures (perylene, cadalene, rethene) and increased concentrations of naphthidogenic PAHs (phenanthrene, alkyl-phenanthrenes), indicates the genetic association with the shore coal deposits. The Shtockman and Kola-Kanin Monocline sediments revealed other general trends in PAHs distribution. They are distinguished by a lower maturity level (MPI1Atlantic flow, as well as an increased level of sediments contamination (high content of pyrogenic PAHs) should be considered. Thus, the character of the group composition and hydrocarbons

  14. Dense water cascading, bottom currents and sediment wave formation at the exit of the Bari canyon (Southern Adriatic Sea, Italy)

    Science.gov (United States)

    Langone, Leonardo; Miserocchi, Stefano; Boldrin, Alfredo; Turchetto, Margherita; Foglini, Federica; Trincardi, Fabio

    2010-05-01

    The dense water forming in the North Adriatic (NAdDW) spreading southward along the Italian continental shelf, sinks in the Southern Adriatic basin through particular cascading events. Such events are seasonal, occurring specially in April, with variable intensity. These phenomena control the water mass mixing, the deep ocean ventilation, the behaviour of deep ecosystems, the formation of complex erosive and depositional bedforms and the abyssal export and burial of nutrients and carbon. Because of the NadDW formation is linked to climate factors (frequency, duration and size of Bura winds), the temporal variations of the NadDW dispersion into the Southern Adriatic allow to make inferences of the impact of recent climate changes on the ecosystems of the deep Mediterranean Sea. Previous research projects (EuroStrataform, HERMES) acquired a large data set of bathymetric, side-scan sonar (TOBI) and Chirp sonar profiles, which were used to build detailed morpho-bathymetric maps of the Southern Adriatic margin. There, the seabed is extremely complex, characterized by a large variety of bedforms (sediment waves, erosive scours, longitudinal furrows and giant comet marks). A branch of the cascading NAdDW is confined and accelerated through the Bari canyon where it produces a strong current capable of reaching down-slope velocities greater than 60 cm s-1 near the bottom at ~600 m of water depth, eroding the canyon thalweg and entraining large amounts of fine-grained sediment. At the exit of the canyon, in water depth greater than 800 m, the current becomes less confined, spreads laterally and generates an 80-km2-wide field of mud waves; these bedforms migrate up current and show amplitudes up to 50 m and wavelengths of about 1 km. Cruise IMPACT-09 of RV Urania was carried out in the Southern Adriatic Sea from 17-30 March 2009 with main scope of studying the impact of NadDW cascading events on the deep ecosystems of the Southern Adriatic. Experiments planned in the cruise

  15. The comparative statuses of the Far Eastern seas and the northwestern Pacific Ocean based on the range of integral characteristics of pelagic and bottom trawl macrofauna

    Directory of Open Access Journals (Sweden)

    Igor V. Volvenko

    2015-03-01

    Full Text Available Comparison of the pelagial and benthal of the Far Eastern seas (mainly within the borders of the Russian EEZ and the contiguous part of the Pacific Ocean according to the macrofauna population density, species richness, evenness and diversity, and average individual weight of animals, is provided on the basis of the results of multiannual broad-scale pelagic and bottom trawl surveys carried out in 1977–2010.

  16. Biogeochemistry of near-bottom suspended particulate matter of the Beaufort Sea shelf (Arctic Ocean): C, N, P, δ 13C and fatty acids

    Science.gov (United States)

    Connelly, Tara L.; Deibel, Don; Parrish, Christopher C.

    2012-07-01

    The influence of the Mackenzie River on the source, composition, and distribution of dissolved nutrients and suspended particulate matter (SPM) in near-bottom waters on the Beaufort Sea shelf was determined by measuring particulate organic carbon (POC), particulate nitrogen (PN), particulate phosphorus (PP), elemental ratios (C:N, C:P, N:P), chlorophyll a, bulk δ 13C, and fatty acids. The Mackenzie River had a strong influence on the composition of SPM in near-bottom waters across the entire Canadian Beaufort Sea shelf, including the Amundsen Gulf. This influence was strongest at stations near the river mouth and decreased offshore and northeastward towards the Amundsen Gulf, as seen in SPM elemental concentrations, δ 13C, and terrestrial plant fatty acid markers. Low C:N ratios and high relative levels of odd-numbered carbon and branched-chained fatty acids (bacterial fatty acid markers) indicated that bacteria were an important contributor to organic matter at stations near the river and on the Mackenzie shelf. Fatty acid analysis allowed detection of a phytoplankton sinking event in the Amundsen Gulf in which polyunsaturated fatty acid (PUFA) levels in near-bottom waters significantly increased from June to July. However, this change in PUFA was not associated with any observed temporal change in chlorophyll a, δ 13C, or C:N ratios. These results show that a multiple biomarker approach is necessary in ecosystem studies of dynamic environments such as near-bottom waters or river-influenced shelves.

  17. Living (Rose Bengal stained benthic foraminiferal faunas along a strong bottom-water oxygen gradient on the Indian margin (Arabian Sea

    Directory of Open Access Journals (Sweden)

    C. Caulle

    2015-02-01

    Full Text Available Rose Bengal stained foraminiferal assemblages were analysed along a five-station bathymetric transect across the core and the lower part of the oxygen minimum zone (OMZ on the Indian margin of the Arabian Sea. Sediment cores were collected using the manned submersible Shinkai 6500 during RV Yokosuka cruise YK08-11 in the post-monsoon season (October 2008 at water depths ranging from 535 to 2000 m, along a gradient from almost anoxic to well-oxygenated (0.3 to 108 μM bottom waters. Stained foraminiferal densities were very high in the OMZ core (535 m and decreased with depth. The faunas were dominated (40–80% by non-calcareous taxa at all stations. These were mainly species of Reophax and Lagenammina but also included delicate monothalamous taxa (organic-walled "allogromiids", agglutinated saccamminids, psammosphaerids and tubular forms. These new data from the Indian margin are compared to previous studies from the Murray Ridge, the Pakistan margin and the Oman margin. The fact that similar species were found at sites with comparable bottom-water oxygen concentrations but with very different surface water productivity suggests that, within the strongly developed Arabian Sea OMZ, bottom-water oxygen concentration, and not the organic flux to the sea floor, is the main factor controlling the species composition of the foraminiferal communities. Several foraminiferal species (e.g. Praeglobobulimina sp. 1, Ammodiscus sp. 1, Bolivina aff. dilatata were confined to the core of the OMZ and are presently known only from the Arabian Sea. Because of their association with extremely low-oxygen concentration, these species may prove to be good indicators of past OMZ variability in the Arabian Sea.

  18. Near-bottom water column anomalies associated with active hydrothermal venting at Aeolian arc volcanoes, Tyrrhenian Sea, Italy

    Science.gov (United States)

    Walker, S. L.; Carey, S.; Bell, K. L.; Baker, E. T.; Faure, K.; Rosi, M.; Marani, M.; Nomikou, P.

    2012-12-01

    Hydrothermal deposits such as metalliferous sediments, Fe-Mn crusts, and massive sulfides are common on the submarine volcanoes of the Aeolian arc (Tyrrhenian Sea, Italy), but the extent and style of active hydrothermal venting is less well known. A systematic water column survey in 2007 found helium isotope ratios indicative of active venting at 6 of the 9 submarine volcanoes surveyed plus the Marsili back-arc spreading center (Lupton et al., 2011). Other plume indicators, such as turbidity and temperature anomalies were weak or not detected. In September 2011, we conducted five ROV Hercules dives at Eolo, Enarete, and Palinuro volcanoes during an E/V Nautilus expedition. Additionally, two dives explored the Casoni seamount on the southern flank of Stromboli where a dredge returned apparently warm lava in 2002 (Gamberi, 2006). Four PMEL MAPRs, with temperature, optical backscatter (particles), and oxidation-reduction potential (ORP) sensors, were arrayed along the lowermost 50 m of the Hercules/Argus cable during the dives to assess the relationship between seafloor observations and water column anomalies. Active venting was observed at each of the volcanoes visited. Particle anomalies were weak or absent, consistent with the 2007 CTD surveys, but ORP anomalies were common. Venting at Eolo volcano was characterized by small, localized patches of yellow-orange bacteria; living tubeworms were observed at one location. ORP anomalies (-1 to -22 mv) were measured at several locations, primarily along the walls of the crescent-shaped collapse area (or possible caldera) east of the Eolo summit. At Enarete volcano, we found venting fluids with temperatures up to 5°C above ambient as well as small, fragile iron-oxide chimneys. The most intense ORP anomaly (-140 mv) occurred at a depth of about 495 m on the southeast side of the volcano, with smaller anomalies (-10 to -20 mv) more common as the ROV moved upslope to the summit. At Palinuro volcano, multiple dives located

  19. High Performance Bottom-Gate-Type Amorphous InGaZnO Flexible Transparent Thin-Film Transistors Deposited on PET Substrates at Low Temperature

    Science.gov (United States)

    Lee, Hsin-Ying; Ye, Wan-Yi; Lin, Yung-Hao; Lou, Li-Ren; Lee, Ching-Ting

    2014-01-01

    The InGaZnO channel layer of bottom-gate-type flexible transparent thin-film transistors was deposited on polyethylene terephthalate substrates using a magnetron radio frequency cosputter system with a single InGaZnO target. The composition of the InGaZnO channel layer was controlled by sputtering at various Ar/O2 gas ratios. A 15-nm-thick SiO y insulator film was used to passivate the InGaZnO channel layer. Much better performances of the passivated devices were obtained, which verified the passivation function. To study the bending stability of the resulting flexible transparent thin-film transistors, a stress test with a bending radius of 1.17 cm for 1,500 s was carried out, which showed a variation in the effective filed-effect mobility and the threshold voltage of the unpassivated and passivated devices being maintained within 10 and 8%, respectively.

  20. Grain size distribution, clay mineralogy and chemistry of bottom sediments from the outer Thermaikos Gulf, Aegean Sea, Greece

    Directory of Open Access Journals (Sweden)

    K.G. PEHLIVANOGLOU

    2012-12-01

    Full Text Available The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite. The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral

  1. Ocean Thermal Energy Conversion: the potential impact on microphytoplankton of bottom water discharge at subsurface in the Caribbean Sea

    Science.gov (United States)

    Giraud, Mélanie; Boye, Marie; Garçon, Véronique; L'Helguen, Stéphane; Donval, Anne; De la Broise, Denis

    2015-04-01

    Part of the solar energy can be harvested and used in different processes. Taking advantage of the natural temperature gradient between the surface and deep ocean, the Ocean Thermal Energy Conversion (OTEC) process fulfills this goal. The IMPALA project (Impacts of artificial upwelling on microplankton) aims to study the potential environmental impacts of releasing, below the surface, deep seawater flowing out of a scheduled OTEC pilot plant offshore the Martinique Island in the Caribbean Sea. Biogeochemical processes involved in the artificial upwelling generated by the use of an Ocean Thermal Energy Conversion (OTEC) plant were studied in this poor nutrient environment. The biogeochemical and physical ecosystem structure and functioning on the OTEC site were described and deep seawater discharge using in situ microcosm experiments was carried out off Martinique. Surface seawater was collected in ultra-clean conditions at two depths (corresponding to the maximum of chlorophyll a concentration and bottom of nutricline) and mixed in different proportions with deep seawater (2% and 10%). Pigments determination, picophytoplankton abundance, macro-nutrients (silicates, nitrates, and phosphates), particular organic carbon and nitrogen concentrations and primary production were documented to assess the variability between the natural environment and within the microcosms. The latter were immersed for 6 days on a 250 meters mooring. Variations observed in microcosms experiments and in the surrounding waters were compared in order to evaluate the natural variability of the phytoplankton assemblage and the potential shifts induced by deep water supply. Results obtained during two fields campaigns conducted off Martinique at the onset of the dry (November-December 2013) and wet seasons (June 2014), respectively, will be presented and discussed. Incubating mixtures of subsurface and deep waters at two ratios and at two depths, allows evaluating the potential impact of a deep

  2. Bottom Sediment Granulometric Data for the Continental Margins of the Bering, Chukchi, East Siberia, Laptev, and Beaufort Seas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of Roberts, Richard W., University of Washington, Department of Oceanography Special Report No. 70, Bottom Sediment Granulometric Data for the...

  3. Impact of Bottom Trawling on Deep-Sea Sediment Properties along the Flanks of a Submarine Canyon

    OpenAIRE

    Jacobo Martín; Pere Puig; Pere Masqué; Albert Palanques; Anabel Sánchez-Gómez

    2014-01-01

    The offshore displacement of commercial bottom trawling has raised concerns about the impact of this destructive fishing practice on the deep seafloor, which is in general characterized by lower resilience than shallow water regions. This study focuses on the flanks of La Fonera (or Palamós) submarine canyon in the Northwestern Mediterranean, where an intensive bottom trawl fishery has been active during several decades in the 400-800 m depth range. To explore the degree of alteration of surf...

  4. Polycyclic aromatic hydrocarbons (PAHs) in bottom sediments of the Kara Sea shelf, Gulf of Ob and Yenisei Bay.

    Science.gov (United States)

    Dahle, Salve; Savinov, Vladimir M; Matishov, Gennadij G; Evenset, Anita; Naes, Kristoffer

    2003-05-01

    PAH concentration and distribution has been examined in surface sediments samples from the Kara Sea, Russia. The study includes 13 samples from the South-eastern Kara Sea shelf, one sample from the south-western part of the sea, 4 samples from the Baydaratskaya Bay, 5 samples from the Gulf of Ob and 4 samples from the Yenisei Bay, collected in August-September 1993-1994. Cluster analysis and principal component analysis (PCA) were used to identify common patterns and possible sources of PAHs. The total PAH concentration (sum of two- to six-ring aromatic hydrocarbons) in the Kara Sea sediments was generally lower than in the Barents Sea sediments and comparable to the levels in the Pechora and White seas. Two- and three-ring aromatic hydrocarbons predominated in Kara Sea sediments, which indicate a relatively stronger petrogenic origin than that in the adjacent seas. The highest total PAH concentrations within the Kara Sea were found in sediments from the Yenisei Bay and in the South-western part of the Kara Sea in the Eastern Novaya Zemlya Trough. The PAHs of the Yenisei Bay sediments were dominated by perylene and PAHs of petrogenic origin, but had also a strong indication of PAHs of pyrogenic origin. The dominating PAH group in the South-western part of the Kara Sea were four- to six-ring aromatic hydrocarbons, indicating pyrogenic origin. Perylene levels were high in all the Kara Sea samples, and highest levels were found in areas of strong terrigenous influence. The most probable source is decaying peat products being transported to the Kara Sea by both large and small rivers. PMID:12699918

  5. Effects of water depth and substrate color on the growth and body color of the red sea cucumber, Apostichopus japonicus

    Science.gov (United States)

    Jiang, Senhao; Dong, Shuanglin; Gao, Qinfeng; Ren, Yichao; Wang, Fang

    2015-05-01

    Three color variants of the sea cucumber, Apostichopus japonicus are recognized, the red one is highly valued in the market. When the red variant is cultured in ponds in China, its body color changes from red to celadon in 3-6 months. The effects of water depth and substrate color on the growth and body color of this animal were investigated. Juveniles of red A. japonicus were cultured in cages suspended at a range of water depths (20, 50, 100, 150 and 200 cm). The specific growth rate of red sea cucumbers was significantly higher in animals cultured at deeper water layers compared with those grown at shallowers. Body weights were greatest for sea cucumbers cultured at a depth of 150 cm and their survival rates were highest at a depth of 200 cm. A scale to evaluate the color of red sea cucumbers ( R value) was developed using a Pantone standard color card. All stocked animals in the 9-month trial retained a red color, however the red body color was much more intense in sea cucumbers cultured at shallower depths, while animals suspended in deeper layers became pale. In a separate trial, A. japonicus were cultured in suspended cages with seven different colored substrates. Substrate color had a significant effect on the growth and body-color of red A. japonicus. The yield were greatest for A. japonicus cultured on a yellow substrate, followed by green > white > orange > red > black and blue. All sea cucumbers in the 7-month trial retained a red color, although the red was most intense (highest R value) in animals cultured on a blue substrate and pale (lowest R value) for animals cultured on a green substrate.

  6. Engineered luciferase reporter from a deep sea shrimp utilizing a novel imidazopyrazinone substrate.

    Science.gov (United States)

    Hall, Mary P; Unch, James; Binkowski, Brock F; Valley, Michael P; Butler, Braeden L; Wood, Monika G; Otto, Paul; Zimmerman, Kristopher; Vidugiris, Gediminas; Machleidt, Thomas; Robers, Matthew B; Benink, Hélène A; Eggers, Christopher T; Slater, Michael R; Meisenheimer, Poncho L; Klaubert, Dieter H; Fan, Frank; Encell, Lance P; Wood, Keith V

    2012-11-16

    Bioluminescence methodologies have been extraordinarily useful due to their high sensitivity, broad dynamic range, and operational simplicity. These capabilities have been realized largely through incremental adaptations of native enzymes and substrates, originating from luminous organisms of diverse evolutionary lineages. We engineered both an enzyme and substrate in combination to create a novel bioluminescence system capable of more efficient light emission with superior biochemical and physical characteristics. Using a small luciferase subunit (19 kDa) from the deep sea shrimp Oplophorus gracilirostris, we have improved luminescence expression in mammalian cells ~2.5 million-fold by merging optimization of protein structure with development of a novel imidazopyrazinone substrate (furimazine). The new luciferase, NanoLuc, produces glow-type luminescence (signal half-life >2 h) with a specific activity ~150-fold greater than that of either firefly (Photinus pyralis) or Renilla luciferases similarly configured for glow-type assays. In mammalian cells, NanoLuc shows no evidence of post-translational modifications or subcellular partitioning. The enzyme exhibits high physical stability, retaining activity with incubation up to 55 °C or in culture medium for >15 h at 37 °C. As a genetic reporter, NanoLuc may be configured for high sensitivity or for response dynamics by appending a degradation sequence to reduce intracellular accumulation. Appending a signal sequence allows NanoLuc to be exported to the culture medium, where reporter expression can be measured without cell lysis. Fusion onto other proteins allows luminescent assays of their metabolism or localization within cells. Reporter quantitation is achievable even at very low expression levels to facilitate more reliable coupling with endogenous cellular processes. PMID:22894855

  7. Gastropod shell as a substrate for cocoon deposition by the deep-sea fish leech Notostomum cyclostomum (Hirudinida: Piscicolidae)

    OpenAIRE

    Nagasawa,Kazuya; Ueda, Yuji

    2013-01-01

    Cocoons of the piscicolid leech Notostomum cyclostomum Johansson, 1898 were found on the shell of the whelk Buccinum striatissimum collected at 200 m in depth in the southern Sea of Japan off Hyogo Prefecture, central Japan. The leech appears to utilize whelks as well as snow crabs Chionoecetes opilio as a substrate for cocoon deposition.

  8. Crustacean fishery with bottom traps in an area of the southern Tyrrhenian Sea: species composition, abundance and biomass

    Directory of Open Access Journals (Sweden)

    L. CASTRIOTA

    2012-12-01

    Full Text Available The north-eastern coast of Sicily is characterized by deep, steep bottoms, not easily exploitable by trawl fishery. In this area few fishermen use bottom traps to catch shrimps and Norway lobsters. Our studies were aimed at identifying the species’ composition, abundance and biomass of crustaceans exploitable by bottom traps in this area. Monthly samples over one year were obtained from two lines of 30 baited traps each, at depths between 100 and 500 m. One line was placed in an area usually exploited by this fishery; the other line was used in the unexploited deepest bottoms. Trapped specimens were counted and weighed. ANOVA test, post hoc multiple comparisons and Student’s t test were applied on abundance and biomass data, for testing differences between areas, among seasons and species. During 22 fishing days, 23 species characteristic of the bathyal mud assemblage were caught, 8 of which were not considered commercial. Plesionika edwardsii was the most important species, recorded in the whole bathymetric range investigated; Nephrops norvegicus was significantly higher in terms of biomass in the unexploited area. The discard, of slight importance, was mostly represented by the crab Liocarcinus depurator. Spring season yielded the best catches in both areas, showing the highest values for both abundance and biomass

  9. Evidence for the Late Cenozoic Antarctic Ice Sheet evolution and bottom current dynamics in the central-western Ross Sea outer margin, Antarctica

    Science.gov (United States)

    Kim, Sookwan; De Santis, Laura; Kuk Hong, Jong; Cottlerle, Diego; Petronio, Lorenzo; Colizza, Ester; Bergamasco, Andrea; Kim, Young-Gyun; Kang, Seung-Goo; Kim, Hyoungjun; Kim, Suhwan; Wardell, Nigel; Geletti, Riccardo; McKay, Robert; Jin, Young Keun; Kang, Sung-Ho

    2016-04-01

    Sedimentary records in polar continental margins provide clues for understanding paleo-depositional environments, related to ice sheet evolution and bottom-water current dynamics, during times of past climate and global sea level changes. Previous seismostratigraphic studies of the Ross Sea embayment, Antarctica, illustrated its general stratigraphic framework and the distribution of glacial sedimentary features over the continental shelf, since the onset of Antarctic ice-sheets at the Eocene-Oligocene boundary (~34.0 Ma). In contrast, there are a fewer studies for the outer continental margin, where continuous sedimentary deposits generally preserve the record of past climate cycles with minimum hiatus, comparing to the inner- and mid-continental shelf, where grounding ice streams eroded most of the sediments. Here we present a seismostratigraphic analysis of 2-D multichannel seismic reflection profiles, from the Central Basin located in the central-western Ross Sea outer margin. A glacial prograding wedge developed at the mouth of the Joides Basin since early-middle Miocene times (RSU4: ~14.0 Ma). And the Central Basin was filled with stacked debris-flow deposits and turbidites. The sediment depocenter shifted from the Central Basin toward the slope in the Pliocene (after RSU2: ~3.3 Ma). Pliocene foreset beds are steep and pinch out at the base of the continental slope. Bottom current controlled sediment drifts well developed since the middle Miocene, along the western slope of the central Basin and on the basement highs These areas are far from the mouth of the Joides trough, where most of the glacial sediment is deposited, and they are also more elevated than the basinal areas, where gravity flow maximum thickness accumulated. Along the western slope of the central Basin and over the basement highs, the signature in the sediments of the action of bottom current reworking and shaping the sea floor can be then clearly recognized. We present the sediment drifts

  10. Observation of bottom water renewal and export production in the japan basin, east sea using tritium and helium isotopes

    Science.gov (United States)

    Hahm, Doshik; Kim, Kyung-Ryul

    2008-03-01

    Tritium (3H or T) has been produced mostly by atmospheric nuclear weapon tests, and entered the ocean in the form of water (HTO). As tritium exists as water itself, it has been regarded as an ideal tool to study the transport of water masses. In April 2001 we collected water samples in the western Japan Basin (WJB) for tritium and helium measurement. The timely sampling provided direct evidence of the bottom water formation, resulting in the drastic increase in tritium concentration from 0.3 TU in 2000 to 0.67 TU in 2001. Considering that the new bottom waters were found mostly in the WJB, it implies that maximum 1% of the whole bottom layer below 2600 m should be replaced with the surface water during the severely cold winter 2000—2001.3H-3He age, showing the elapsed time since the water left from the surface, can be used to calculate oxygen utilization rate by dividing AOU by the age. Under the condition of 90% oxygen saturation in the surface water, the integration of OUR in the water column below 200 m yields net oxygen consumption of 12 mol (O2) m-2 yr-1, which corresponds to the export production of 99 g C m-2 yr-1 . This estimate is comparable to a previous estimate based on satellite data and implies that the ratio of export to primary production (f -ratio) is as high as 0.5 in the WJB.

  11. Acid-labile sulfides in shallow marine bottom sediments: A review of the impact on ecosystems in the Azov Sea, the NE Black Sea shelf and NW Adriatic lagoons

    Science.gov (United States)

    Sorokin, Yu. I.; Zakuskina, O. Yu

    2012-02-01

    Acid-labile sulfides (LS) increase in bottom sediments at sites in the Azov Sea, at the NE Black Sea shelf and in the coastal lagoons of NW Adriatic Sea experiencing direct impacts of anthropogenic pollution. Fresh anthropogenic organic matter stimulates the bacterial sulfate reduction and here the rate of the LS production overcomes their loss during the oxidation and pyritization. This results in the expansion of reduced sediment layer up to the bottom surface. The LS concentration in the reduced sediments varies between 300 and 2000 mg S l -1 of wet silt depending on the size of pollution loading and on the rate of sedimentation. In the oxidized sediments away from the direct pollution impact, the LS concentration did not exceed 100-150 mg S l -1. Being a strong cytochrome toxin, the LS adversely affect the coastal ecosystems. The concentrations over 600 mg S l -1 result in quasi total benthic mortality whereas >300-400 mg S l -1 depletes the benthic faunal abundance and taxonomic diversity. Accumulation of the LS in sediments also induces nocturnal hypoxia and stimulates domination of toxic cyanobacteria in the pelagic phytocenoses.

  12. Bottom water production variability in the Ross Sea slope during the Late-Pleistocene-Holocene as revealed by benthic foraminifera and sediment geochemistry

    Science.gov (United States)

    Asioli, A.; Langone, L.; Tateo, F.; Giannossi, M. L.; Giglio, F.; Summa, V.; Piva, A.; Ridente, D.; Trincardi, F.

    2009-04-01

    The Antarctic area produces bottom waters that ventilate the vast majority of the deep basins in the rest of the world ocean. The rate of formation in the source area and the strength of these cold bottom waters affect their flow toward the equator and are key factors affecting the Global Thermohaline Circulation during modern and past climate conditions. We present the results of a multidisciplinary study carried out on a core collected in 2377m of water depth on the slope off the Drygalski Basin (Ross Sea), along the modern path of the bottom waters. The goal of this research is to detect a qualitative signal of possible changes in the rate of bottom water production during the Late Pleistocene-Holocene by integrating micropaleontological and geochemical proxies. The micropaleontological signal is represented by the quantitative and qualitative variations of the agglutinated benthic foraminifera assemblages, while the amount of TOC, nitrogen, δ13C, δ15N, biogenic silica, CaCO3 in the sediment, along with the bulk rock mineralogy, provide information on the paleoproductivity and allow reconstruction of changes in the paleocirculation. The chronology is supported by 14C AMS datings on organic matter. Although this study is still in progress, the results obtained allow the following observations: 1) the Holocene sequence includes a major turnover around 8-8.5 calib kyr BP, leading to reduced nutrient utilization, probably reflecting an increased nutrient supply induced by an enhanced Upper Circumpolar Deep Water upwelling; 2) within this general context, the total concentration of benthic foraminifera preserved in the fossil component records millennial scale cycles of variable amplitude after 8.5 calib kyr BP and to present time. This oscillatory trend is paralleled by other parameters, such as the magnetic susceptibility, the dry density, the sheet silicates and the δ15N; 3) minima in foraminifera concentration reflect relatively increased dissolution, weaker

  13. Phenoloxidase from the sea cucumber Apostichopus japonicus: cDNA cloning, expression and substrate specificity analysis.

    Science.gov (United States)

    Jiang, Jingwei; Zhou, Zunchun; Dong, Ying; Sun, Hongjuan; Chen, Zhong; Yang, Aifu; Gao, Shan; Wang, Bai; Jiang, Bei; Guan, Xiaoyan

    2014-02-01

    Phenoloxidase (PO) is a crucial component of the immune system of echinoderms. In the present study, the full-length cDNA of PO (AjPO) was cloned from coelomocytes of the sea cucumber Apostichopus japonicus using 3'- and 5'-rapid amplification of cDNA ends (RACE) PCR method, which is 2508 bp, with an open reading frame (ORF) of 2040 bp encoding 679 amino acids. AjPO contains a transmembrane domain, and three Cu-oxidase domains with copper binding centers formed by 10 histidines, one cysteine and one methionine respectively. Phylogenetic analysis revealed that AjPO was clustered with laccase-type POs of invertebrates. Using the isolated membrane proteins as crude AjPO, the enzyme could catalyze the substrates catechol, L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine and hydroquinone, but failed to oxidize tyrosine. The results described above collectively proved that AjPO was a membrane-binding laccase-type PO. The quantitative real-time PCR (qRT-PCR) analysis revealed that AjPO mRNA was expressed in muscle, body wall, coelomocytes, tube feet, respiratory tree and intestine with the highest expression level in coelomocytes. AjPO could be significantly induced by lipopolysaccharide (LPS), peptidoglycan (PGN), Zymosan A and polyinosinic-polycytidylic acid (PolyI:C), suggesting AjPO is closely involved in the defense against the infection of bacteria, fungi and double-stranded RNA viruses. PMID:24355405

  14. Effect of bottom type on catch rates of North Sea cod (Gadus morhua) in surveys with commercial fishing vessels

    DEFF Research Database (Denmark)

    Wieland, Kai; Pedersen, Eva Maria; Olesen, Hans Jakob;

    2009-01-01

    Seven surveys with commercial fishing vessels were conducted during a collaborative fishermen-scientist project on the distribution of cod in the north-eastern North Sea between June 2006 and June 2008. A flyshooter, a trawler and a gillnetter participated in this study. In general, catch rates...

  15. Processes controlling forms of phosphorus in surficial sediments from the eastern Arabian Sea impinged by varying bottom water oxygenation conditions

    Digital Repository Service at National Institute of Oceanography (India)

    PrakashBabu, C.; Nath, B.N.

    in OMZ sediments from the NE Arabian Sea may indicate a higher degree of regeneration and diagenetic transformation of labile forms of P to other phases. Authigenic phosphorus (P sub(aut)) fraction varies by a factor of 2-8 in sediments from the OMZ when...

  16. High-resolution AUV-based near bottom magnetic surveys at Palinuro volcanic complex (Southern Tyrrhenian Sea)

    Science.gov (United States)

    Cocchi, L.; Plunkett, S.; Augustin, N.; Petersen, S.

    2013-12-01

    In this paper we present the preliminary results of new near bottom magnetic datasets collected during the recent POS442 cruise using the autonomous underwater vehicle (AUV) Abyss. The Southern Tyrrhenian basin is characterized by deep seafloor interspersed with huge volcanic seamounts (e.g Vavilov and Marsili and those associated to the Aeolian volcanic arc), which were formed during eastward roll back of the Apennine subduction system. These submarine edifices often are affected by significant hydrothermal activity and associated mineral deposits such as those observed at Marsili, Palinuro and Panarea. The western part of the Palinuro volcanic complex is characterized by a half rim of a caldera-like structure and hosts hydrothermal barite-pyrite deposits. Until recently, the full extent of the hydrothermal system remained poorly defined, as exploration has been limited to a few specific sites. In November 2012, a set of high resolution near seafloor geophysical surveys were carried out using GEOMAR's AUV Abyss to attempt to better define the hydrothermal mineralization at Palinuro. Five AUV dives were performed, mapping a total area of 3.7 km2 over the western part of Palinuro. Geomar's Abyss AUV (a Remus6000 class vehicle) was equipped with an Applied Physics Systems flux gate magnetometer, writing to a stand alone data logger, powered by the AUV's main batteries. The 5 dives were performed within the same area but with different primary geophysical sensors (multibeam, sidescan sonar, subbottom profiler), survey altitudes above seafloor (100m, 40m) and line spacing (150m, 100m, 20m). Magnetic data was collect on all five dives. At the beginning of each dive, the AUV performed a set of calibration manoeuvres, involving a 360 degree heading variation, a set of three upwards/downwards pitches, and three port and starboard yaws. This magnetic data reveals the magnetization features of the seafloor in unprecedented detail, highlighting a complex pattern mostly due to

  17. Lithology and late postglacial stratigraphy of bottom sediments in isolated basins of the White Sea coast exemplified by a small lake in the Chupa settlement area (Northern Karelia)

    Science.gov (United States)

    Korsakova, O. P.; Kolka, V. V.; Tolstobrova, A. N.; Lavrova, N. B.; Tolstobrov, D. S.; Shelekhova, T. S.

    2016-05-01

    The complex lithological, geochemical, geochronological, and micropaleontological (diatoms, spores, pollen) investigations of stratified bottom sediments that constitute facies-variable sedimentary sequences in a small isolated lake located near the upper limit of the sea on the White Sea coast made it possible to define lithostratigraphic units (LSU) forming the complete sedimentary succession in deep parts of isolated basins. It is shown that stratigraphy of heterogeneous sequences is determined by two regional transgressive-regressive cycles in relative sea level fluctuations: alternating late Glacial and Holocene transgressions and regressions. The lower part of a clastogenic clayey-sandy-silty sequence successively composed of freshwater (LSU 1) and brackish-water (LSU 2) sediments of the ice-marginal basins and marine postglacial facies (LSU 3) was formed during the late Glacial glacioeustatic marine transgression. Its upper part formed in different isolated basins at different stages of the Holocene is represented depending on its altimetric position on the coastal slope by costal marine sediments (LSU 4) and facies of the partly isolated inlet (LSU 5). The organogenic sapropelic sequence, which overlies sediments of the marine basin and partly isolated bay, corresponds to lithostratigraphic units represented by Holocene sediments accumulated in the meromictic lake (LSU 6), onshore freshwater basin (LSU 7), and freshwater basin with elevated water mineralization (LSU 8) deposited during maximum development of Holocene transgression and lacustrine sediments (LSU 9) formed in coastal environments during terminal phases of the Holocene. The defined lithostratigraphic units differ from each other in lithological, micropaleontological, and geochemical features reflected in structural and textural properties of their sediments, their composition, inclusions, and composition of paleophytocoenoses and diatom assemblages.

  18. Methane flux from sediment into near-bottom water and its variability along the Hel Peninsula—Southern Baltic Sea

    Science.gov (United States)

    Reindl, Andrzej R.; Bolałek, Jerzy

    2014-02-01

    Methane in the sediments of the Bay of Puck occurs in the form of free gas bubbles and is released from the sediments into near-bottom water in the form of a flux. The sediments of the Bay of Puck also contain methanogens whose biological activity results in the production of methane. Research carried out in the coastal areas of the bay along the Hel Peninsula proved the existence of a methane flux ranging from 0.81 mmol m-2 d-1 to 33.41 mmol m-2 d-1 in 2011, while in 2010 ranged from 0.91 mmol m-2 d-1 to 49.15 mmol m-2 d-1. Seasonal and annual fluctuations were also observed. Other factors contributing to the change in methane flux are water temperature and other environmental factors. An increase in temperature causes an increase in the flux. Fluctuations of the flux within individual sampling sites were also observed. A test performed with specific methanogenic inhibitor—sodium dodecyl sulfate (SDS) unexpectedly revealed higher methane concentrations (10-13%) in samples to which SDS was added. We speculate that these higher methane concentration result from the lysis of methane-forming bacteria cells when exposed to SDS.

  19. Variability of PAHs and trace metals in the sediments in relation to environmental characteristics of the bottom layer in the middle Adriatic Sea

    Science.gov (United States)

    Grilli, Federica; Frapiccini, Emanuela; Campanelli, Alessandra; Guicciardi, Stefano; Marini, Mauro; Marasovic, Ivona; Grbec, Branka; Skejić, Sanda; Ujević, Ivana; Lušić, Jelena

    2015-04-01

    In the framework of the project PERSEUS (Policy-oriented marine Environmental Research in the Southern EUropean Seas), two interdisciplinary surveys were carried out in April 2013 and April 2014 in the middle Adriatic Sea along the Pescara-Sibenik transect (Jabuka Pits area) and Vieste-Split transect (Palagruza Sill area) with Croatian research vessel "Bios II" and the Italian research vessel "G. Dallaporta", respectively. The main objective of these research cruises was the implementation of the Marine Strategy Framework Directive (MSFD) in the Adriatic region for collecting physical, chemical and biological data in order to get a better understanding of whole Adriatic ecosystem. The two transects are already recognised as a key areas for the interception and the study of dense water modification (Zore-Armanda, 1963; Marini et al., 2006; Grilli et al., 2013). Due to seasonal circulation patterns, they are characterized by high temporal variability of the thermohaline structure (Grbec and Morović, 1997; Vilibić, et al., 2004) and other oceanographic parameters. Long term oceanographic records from the Middle Adriatic enable better understanding of the ecosystem response to changes of atmospheric and sea conditions through physical, chemical and biological processes (Marasović et al., 1995). Several oceanographic parameters relevant and useful for the ecosystem assessment of the two areas (temperature, salinity, density, fluorescence, oxygen, nutrients, chlorophyll, phyto- and zoo-plankton as well as selected pollutants , trace metals and Polycyclic Aromatic Hydrocarbons-PAHs in sediments) were collected. In the present work, the variations of PAHs and trace metals concentration in the marine sediments are presented in relation to the physical and chemical characteristics of the bottom layer. A constant influx of metal induces more intense accumulation of anthropogenic metals, especially Cd, in sediment from Jabuka Pit, and the metal content slightly increases

  20. Ocean Bottom Gamma-Ray Anomaly Around Methane Seeps Related to Gas Hydrate- Bearing Zone in The Eastern Margin of Japan Sea and Off Southwest Taiwan

    Science.gov (United States)

    Machiyama, H.; Kinoshita, M.; Lin, S.; Matsumoto, R.; Soh, W.

    2008-12-01

    JAMSTEC has conducted the ocean bottom gamma-ray measurement using ROVs and Submersibles since 1997. Gamma-ray spectrometer utilizes 3-inch spherical NaI(Tl) scintillator and the signal processor including DA converter in a pressure case. After processing data, we get total count rate (intensity value: count per second (cps)) of gamma ray and contents of K, U-, and Th-series radionuclides. The sensor was equipped to the side of the sample basket or foot of ROVs and submersibles, and always touches the seafloor when ROVs completely landed. Their results are posted on JAMSTEC website as a database. On the basis of past achievements, we present the results of the ocean bottom gamma-ray measurement at the methane seep sites related to gas hydrate off Joetsu in the eastern margin of Japan Sea and off southwest Taiwan. Off Joetsu: A number of mounds, large pockmarks (20 - 50 m deep and 200 - 500 m across), gas plumes, and gas hydrate are found at water depth of 900 - 1000 m in the Umitaka Spur and the Joetsu Knoll. Gamma-ray intensity values are 50 - 70 cps in normal muddy seafloor. On the other hand, the intensity values are 100 - 200 cps around methane venting sites, bacteria mats, and 'collapsed hydrate zone' which has an undulating, rugged seafloor with carbonate nodules and gravels. Contents of each radionuclide are also high. Low U/Th ratio suggests that there is less contribution of Rn accompanied with a recent fault activity. Off southwest Taiwan: Large, dense chemosynthetic communities, associated with carbonate pavements, were discovered at water depth of about 1100 - 1200 m on the top of the Formosa Ridge. Gamma-ray intensity values in normal muddy seafloor (120 - 150 cps) are higher than those around Japan. Since Th-series radionuclide easily absorbs other particles, it is commonly included in surface sediments. This may cause higher content of Th-series radionuclide in normal muddy seafloor. On the other hand, anomaly of gamma-ray intensity (200 - 300 cps

  1. Substrate utilization in sea level residents during exercise in acute hypoxia and after 4 weeks of acclimatization to 4100 m

    DEFF Research Database (Denmark)

    Lundby, C; Van Hall, Gerrit

    2002-01-01

    To investigate the effect of acclimatization to hypoxia on substrate utilization, eight sea level residents were studied during exercise at the same relative (rel) and absolute (abs) work rate as at sea level (SL), under acute (AH), and after 4 weeks exposure to 4100 m altitude (CH). Carbohydrate...... (CHO) and fat oxidation during exercise at SL were 2.0 +/- 0.2 and 0.3 +/- 0.0 g min(-1), respectively. At AHabs and CHabs CHO oxidation increased (P < 0.05) to 2.5 +/- 0.2 and 2.3 +/- 0.1 for CHO, and fat oxidation decreased (P < 0.05) to 0.2 +/- 0.01 and 0.2 +/- 0.01 g min(-1), respectively. Exercise...

  2. AFSC/RACE/GAP/vonSzalay: The Eastern Bering Sea Shelf, Gulf of Alaska, and Aleutian Islands Simrad ES 60 Acoustic Data Collected on Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Calibrated midwater and bottom backscatter data collected continuously with ES-60 echosounders throughout the bottom trawlsurvey period, continuing a time series of...

  3. Charmed Bottom Baryon Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Zachary S; Detmold, William; Meinel, Stefan; Orginos, Kostas

    2014-11-01

    The spectrum of doubly and triply heavy baryons remains experimentally unexplored to a large extent. Although the detection of such heavy particle states may lie beyond the reach of exper- iments for some time, it is interesting compute this spectrum from QCD and compare results between lattice calculations and continuum theoretical models. Several lattice calculations ex- ist for both doubly and triply charmed as well as doubly and triply bottom baryons. Here, we present preliminary results from the first lattice calculation of doubly and triply heavy baryons including both charm and bottom quarks. We use domain wall fermions for 2+1 flavors (up down and strange) of sea and valence quarks, a relativistic heavy quark action for the charm quarks, and non-relativistic QCD for the heavier bottom quarks. We present preliminary results for the ground state spectrum.

  4. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Tutuila Island, American Samoa, South Pacific.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Tutuila Island,...

  5. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Tau Island, Territory of American Samoa, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Ta'u Island,...

  6. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Swains Island, Territory of American Samoa, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymetry derivatives at Swains Island,...

  7. CRED Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at the U.S. Territory of Guam.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at the U.S....

  8. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at French Frigate Shoals, Northwest Hawaiian Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at French Frigate...

  9. Preliminary hard and soft bottom seafloor substrate map derived from gridded sidescan and bathymetry derivatives at Apra Harbor, Guam U.S. Territory.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map classified from sidescan data and bathymetric derivatives at Apra Harbor, Guam U.S. Territory. The dataset was...

  10. An Effective Method to Determine the Distribution Boundary of Cobalt-Rich Fe-Mn Crusts on a Guyot: Synchronous Application of Sub-bottom Profiling and Deep-Sea Video Recording

    Institute of Scientific and Technical Information of China (English)

    He Gaowen; Liang Donghong; Song Chengbin; Sun Xiaoming; Wu Shuigen; Zhou Jianping; Zhang Xuehua

    2005-01-01

    Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between the sub-bottom structures, revealed by sub-bottom profiling, and crust distribution can be revealed for the first time by the synchronous application of sub-bottom profiling and deep-sea video recording. The lower boundary of the sediment corresponds with the upper boundary of the crust. By analysis of these two kinds of data, the lower boundary of the sediment can be determined; therefore, the upper boundary of the crust distribution can be deduced. According to this method of analysis, the upper boundary of water depth of crust distribution of a seamount in the western Pacific is about 1 560 m.

  11. High-resolution sub-bottom sonar imaging and 3D modeling of drowned Pleistocene river paleochannel architecture (Strunjan bay, Adriatic Sea)

    Science.gov (United States)

    Trobec, Ana; Šmuc, Andrej; Poglajen, Sašo; Vrabec, Marko

    2015-04-01

    In the Gulf of Trieste (northern Adriatic), the seafloor is covered by up to several 100s of m of continental sediments, characterized predominately by alluvial and aeolian deposits that formed during Pleistocene sea-level lowstands. High-resolution multibeam bathymetry revealed the existence of several meandering river channels. One such channel appears to be vertically offset across a linear, NE-SW striking morphological flexure, which could be an expression of active faulting. Initial sub-bottom sonar profiles showed abrupt terminations of subhorizontal strata of Pleistocene sediments which roughly coincide with the flexure position. To obtain a high-resolution 3D interpretation of this peculiar feature, we investigated the outermost part of the Strunjan bay (southern Slovenian coast). A grid of 25 m spaced sub-bottom profiles covering the area of 1225 x 500 m and comprising a total of 71 orthogonal profiles was acquired with the Innomar parametric sediment echo sounder SES-2000, using a sampling interval of 69 μs and a frequency of 8000 Hz. Data processing included conversion from proprietary to standard SEG-Y data format, deconvolution, elimination of swell movement and Automatic Gain Control. Geopositioned profiles were interpreted and correlated in IHS Kingdom seismic interpretation software, which was used to pick horizons and model 3D geometry of key stratigraphic surfaces. Four distinct acoustic facies were resolved from the sonar profiles to a depth of up to 10 m below the seafloor. The first reflection represents the seafloor, ranging in depth from 20 to 26 m. Acoustic facies A in the immediate subsurface represents Holocene marine sediments that are up to 9 m thick. The paleochannel and associated river deposits are represented in the underlying acoustic facies B. Characteristic for this facies is strong attenuation of signal along the river channel which we interpret as a consequence of lateral channel migration and/or later gas accumulations in this

  12. 用定深爆炸声源反演海底声学参数%Inversion of sea bottom geoacoustic parameters using underwater explosion at fixed depth

    Institute of Scientific and Technical Information of China (English)

    周鸿涛; 魏士俨; 杨燕明; 洪涛

    2015-01-01

    This paper provides the geoacoustic inversion results used broadband data from underwater explosion at fixed depth in an Acoustics Experiment in the South China Sea,2014.Considering sensitivity differences of acous-tic parameters of sediments to physical parameters of sound field and geoacoustic inversion methods,2 approaches are used respectively for different acoustic parameters of sediments.Firstly,acoustic impedance can be achieved by vertical bottom reflective coefficients from sound reflected of sea bottom divided by directly arrived sound.Second-ly,sound velocity and density can also be achieved by combining Hamilton empirical equation to the relationship between acoustic impedance,sound velocity and density of sediments.The Hamilton empirical equation is about sound velocity and density of sediments and another key is to choose appropriate terrain which is continental terrace in this experiment.On different sea bottom,acoustic parameters of sediment samples are measured in laboratory conditions of temperature 23℃ and standard atmospheric pressure 1-atm.As a result,acoustic parameters especial-ly sound velocity need to be corrected to match different temperatures and pressures.Sound velocity is corrected successfully,in this paper,due to the fact that porewater of sediment critically determines sound velocity and the ratio of the sediment sound velocity to the porewater sound velocity is relatively stable even in the conditions that the temperature and pressure varies greatly.Inversion results appear to be well consistent when compared with in situ gravity core measurements and with data from Hamilton.In detail,in terms of acoustic impedance,the gravity core result after correction and the Hamilton conclusion are 2.065 6 ×105 ,2.046 0 ×105 and 2.238 0 ×105 g/(cm2 ·s), respectively.In terms of sound velocity,the gravity core result after correction and the Hamilton conclusion are 1 482.6,1 467.5 and 1 502.8m /s,respectively.In terms of sediment density

  13. Temperature, salinity, dissolved oxygen, phosphate, nitrite, pH, alkalinity, bottom depth, and meteorology data collected from Arctic Seas and North Western Pacific by various Soviet Union institutions from 1925-11-16 to 1989-05-18 (NODC Accession 0075099)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, dissolved oxygen, phosphate, nitrite, pH, alkalinity, bottom depth, and meteorology data collected from Arctic Seas and North Western Pacific...

  14. Concentration maxima of volatile organic iodine compounds in the bottom layer water and the cold, dense water over the Chukchi Sea in the western Arctic Ocean: a possibility of production related to degradation of organic matter

    Directory of Open Access Journals (Sweden)

    A. Ooki

    2015-07-01

    Full Text Available We conducted a shipboard observation over the Chukchi Sea and the Canada Basin in the western Arctic Ocean in September and October 2012 to obtain vertical distributions of four volatile organic iodine compounds (VOIs in seawater. VOIs are believed to play a role in ozone destruction in the troposphere and lower stratosphere. The VOIs observed in this study were iodomethane (CH3I, iodoethane (C2H5I, diiodomethane (CH2I2 and chloroiodomethane (CH2ClI. Maximum concentrations of the four VOIs were found in the bottom layer water over the Chukchi Sea shelf, in which layer the maximum concentration of ammonium (NH4+ also occurred. A significant correlation was observed between C2H5I and NH4+ (correlate coefficient R = 0.93 and between CH3I and NH4+ (R = 0.77, suggesting production of these VOIs increased with degradation of organic matter. Over the northern Chukchi Sea shelf–slope area, concentration maxima of CH2I2, CH2ClI, and CH3I were found in the subsurface cold, dense water (CDW. A large nitrogen deficit (N-deficit = NH4+ + NO3− + NO2− − 16PO43− simultaneously occurred in this water, suggesting production of the three VOIs in the sediment or the bottom layer water over the shelf, probably in association with degradation of organic matter. We conclude that VOI production over the Chukchi Sea shelf can be largely attributed to the degradation of organic matter that is produced in the highly productive shelf water. High concentrations of CH2ClI were also found in the Alaskan Coastal Water (ACW from the Bering Strait to the surface of the northern Chukchi slope. The VOIs that originated at the Chukchi Sea shelf are expected to be laterally transported to the Arctic Ocean Basin though the subsurface CDW and the surface ACW.

  15. Concentration maxima of volatile organic iodine compounds in the bottom layer water and the cold, dense water over the Chukchi Sea in the western Arctic Ocean: a possibility of production related to degradation of organic matter

    Science.gov (United States)

    Ooki, A.; Kawasaki, S.; Kuma, K.; Nishino, S.; Kikuchi, T.

    2015-07-01

    We conducted a shipboard observation over the Chukchi Sea and the Canada Basin in the western Arctic Ocean in September and October 2012 to obtain vertical distributions of four volatile organic iodine compounds (VOIs) in seawater. VOIs are believed to play a role in ozone destruction in the troposphere and lower stratosphere. The VOIs observed in this study were iodomethane (CH3I), iodoethane (C2H5I), diiodomethane (CH2I2) and chloroiodomethane (CH2ClI). Maximum concentrations of the four VOIs were found in the bottom layer water over the Chukchi Sea shelf, in which layer the maximum concentration of ammonium (NH4+) also occurred. A significant correlation was observed between C2H5I and NH4+ (correlate coefficient R = 0.93) and between CH3I and NH4+ (R = 0.77), suggesting production of these VOIs increased with degradation of organic matter. Over the northern Chukchi Sea shelf-slope area, concentration maxima of CH2I2, CH2ClI, and CH3I were found in the subsurface cold, dense water (CDW). A large nitrogen deficit (N-deficit = NH4+ + NO3- + NO2- - 16PO43-) simultaneously occurred in this water, suggesting production of the three VOIs in the sediment or the bottom layer water over the shelf, probably in association with degradation of organic matter. We conclude that VOI production over the Chukchi Sea shelf can be largely attributed to the degradation of organic matter that is produced in the highly productive shelf water. High concentrations of CH2ClI were also found in the Alaskan Coastal Water (ACW) from the Bering Strait to the surface of the northern Chukchi slope. The VOIs that originated at the Chukchi Sea shelf are expected to be laterally transported to the Arctic Ocean Basin though the subsurface CDW and the surface ACW.

  16. Bottom production

    International Nuclear Information System (INIS)

    In the context of the LHC experiments, the physics of bottom flavoured hadrons enters in different contexts. It can be used for QCD tests, it affects the possibilities of B decays studies, and it is an important source of background for several processes of interest. The physics of b production at hadron colliders has a rather long story, dating back to its first observation in the UA1 experiment. Subsequently, b production has been studied at the Tevatron. Besides the transverse momentum spectrum of a single b, it has also become possible, in recent time, to study correlations in the production characteristics of the b and the b. At the LHC new opportunities will be offered by the high statistics and the high energy reach. One expects to be able to study the transverse momentum spectrum at higher transverse momenta, and also to exploit the large statistics to perform more accurate studies of correlations

  17. Bottom production

    Energy Technology Data Exchange (ETDEWEB)

    Baines, J.; Baranov, S.P.; Bartalini, P.; Bay, A.; Bouhova, E.; Cacciari, M.; Caner, A.; Coadou, Y.; Corti, G.; Damet, J.; Dell-Orso, R.; De Mello Neto, J.R.T.; Domenech, J.L.; Drollinger, V.; Eerola, P.; Ellis, N.; Epp, B.; Frixione, S.; Gadomski, S.; Gavrilenko, I.; Gennai, S.; George, S.; Ghete, V.M.; Guy, L.; Hasegawa, Y.; Iengo, P.; Jacholkowska, A.; Jones, R.; Kharchilava, A.; Kneringer, E.; Koppenburg, P.; Korsmo, H.; Kramer, M.; Labanca, N.; Lehto, M.; Maltoni, F.; Mangano, M.L.; Mele, S.; Nairz, A.M.; Nakada, T.; Nikitin, N.; Nisati, A.; Norrbin, E.; Palla, F.; Rizatdinova, F.; Robins, S.; Rousseau, D.; Sanchis-Lozano, M.A.; Shapiro, M.; Sherwood, P.; Smirnova, L.; Smizanska, M.; Starodumov, A.; Stepanov, N.; Vogt, R.

    2000-03-15

    In the context of the LHC experiments, the physics of bottom flavoured hadrons enters in different contexts. It can be used for QCD tests, it affects the possibilities of B decays studies, and it is an important source of background for several processes of interest. The physics of b production at hadron colliders has a rather long story, dating back to its first observation in the UA1 experiment. Subsequently, b production has been studied at the Tevatron. Besides the transverse momentum spectrum of a single b, it has also become possible, in recent time, to study correlations in the production characteristics of the b and the b. At the LHC new opportunities will be offered by the high statistics and the high energy reach. One expects to be able to study the transverse momentum spectrum at higher transverse momenta, and also to exploit the large statistics to perform more accurate studies of correlations.

  18. Investigation of Hydrodynamic Characteristics of Submarine Moving Close to the Sea Bottom with CFD Methods%潜艇近海底运动水动力数值计算分析研究

    Institute of Scientific and Technical Information of China (English)

    吴宝山; 邢福; 匡晓峰; 缪泉明

    2005-01-01

    The motion of a submarine near the sea bottom was paid much attention in the past few years. The RANS-based CFD methods are used to investigate the hydrodynamic characteristics of the DARPA SUBOFF model (DTRC model 5470) moving near a level bottom in this paper. It is concluded that the bottom effects on the submarine hydrodynamics can be expressed in the linear formulae of the bottom clearance parameter ζ 2= (D/H)2 ,i.e.,the bottom effects are rather proportional to the square of the inverse of the clearance H.The numerical study in this paper shows that the RANSbased CFD methods can be used as a practical tool to predict the hydrodynamic forces of a maneuvering submarine at considerable high accuracy.%本文以SUBOFF潜艇模型为研究对象,利用FLUENT6.1软件,数值模拟了无限水域下的变攻角水动力特性曲线,与泰勒水池的模型试验结果比较分析表明,数值模拟具有较好的精度.本文用FLUENT6.1软件进一步计算分析了SUBOFF潜艇模型带攻角、带漂角、不同近底距离直航状态下的水动力特性,结果表明:无论有无攻角和漂角存在,潜艇运动(除阻力外)的五个水动力分量随近底距离的变化与"近底距离倒数平方"呈良好的线性关系,例如,Z(H)∝1/H2,或Z′(ζ)∝ζ2,其中ζ=D/H为无量纲近底参数.

  19. The effect of different artificial substrates on the inhabitation taxis of sea cucumber Apostichopus japonicus%不同类型附着基对刺参栖息趋向性的影响分析

    Institute of Scientific and Technical Information of China (English)

    管敏; 王印庚; 陈贵平; 廖梅杰; 潘鲁青; 薛太山

    2012-01-01

    By calculating and analyzing the average gathered number of unit volume (AG-NUV) and the mean attractive rate (MAR) on ten types of artificial substrates and 8 distributional areas, the inhabitation taxis and selection of Apostichopus japonicus was estimated. The results showed that the attractive effect of 10 substrates was in the following descending order: big poly-arris tile, stone, three-hole brick, small poly-arris tile, U-shaped tile, eddy abnormity tile, triangle tile, cage substrate, sunshade net and bamboo substrate. There was significant difference between the big poly-arris tile and eddy abnormity tile, triangle tile, cage substrate, sunshade net and bamboo substrate. It also showed that the MAR of pool edge angle (21. 02%) was higher than that of pool wall (8. 23%) and pool bottom surface (15. 68%) , while the MAR underneath and inside of substrate was respectively higher than that of upside and surface. In addition, the experimental test approved the following: (1) The big poly-arris tile had the best performance in the attractive effect; (2) The sea cucumber had an habit that they tended to stay on different location at different time; (3) Stone, cage substrate and sunshade net were not suitable for sea cucumber culture. The attractive effect of several substrates was compared and analyzed in this study.%利用单位体积平均聚集数量(Average Gathered Number of Unit Volume,AGNUV)和平均聚集率(Mean Attractive Rate,MAR)统计分析了刺参对10种附着基(石块、三角瓦、U形瓦、遮阳网、网笼附着基、竹制附着基、三孔砖、涡流式异形瓦、大多棱瓦、小多棱瓦)和8种栖息分布区域(池壁面、池棱角、池底面、附着基上、附着基下、附着基棱角凹槽处、附着基内、附着基外)的选择趋向差异性.结果表明,不同类型附着基诱集刺参的效果为:大多棱瓦>石块>三孔砖>小多棱瓦>U形瓦>涡流式异形瓦>三角瓦>网笼附着基>遮阳网

  20. 相关测速声呐海底回波仿真系统设计%The simulation design of sea-bottom backscattering for correlation velocity log system

    Institute of Scientific and Technical Information of China (English)

    李丹丹; 陈龙; 王长红

    2014-01-01

    相关测速声呐通过对回波数据的空间相关函数与空间相关函数理论公式进行模型匹配来获得载体速度等信息。回波空间相关函数的主瓣宽度影响载体的速度估计及精度。因此对海底回波空间相关函数特性的研究就显得尤为重要。依据相关测速声呐的工作特点,提出了采用Model-View-Controller(MVC)模式构建相关测速声呐海底回波仿真系统的设计方法,并基于VC 6.0软件开发平台将其实现。建立了友好的系统可视化仿真界面,为回波空间相关函数特性的研究提供了便利的平台。%The correlation sonar for velocity measurements (i.e. the correlation velocity log system) obtains the velocity of vessel and other information by using model-matching of the correlation function of echo data with the theoretical correlation function. The main lobe width of the spatial correlation of sea-bottom backscattering influences the accuracy of the vessel velocity estimation. Therefore, it is greatly important to research the spatial correlation of sea-bottom backscattering for correlation sonar. Based on the characteristics of correlation sonar, the MVC design pattern is pro-posed to build the simulation system of sea-bottom backscattering for correlation sonar, and the simulation software is implemented on the VC 6.0 software development platform. Establishing a friendly system of visual communication interface, the simulation software provides a convenient platform for the research on bottom reverberation simulation.

  1. Seismo-acoustic imaging of marine hard substrate habitats: a case study from the German Bight (SE North Sea)

    Science.gov (United States)

    Papenmeier, Svenja; Hass, H. Christian

    2016-04-01

    comparably small foot print which results in high spatial resolution (decimeter in the xyz directions) and hence allows a more precise demarcation of hard substrate areas. Data for this study were recorded in the "Sylt Outer Reef" (German Bight, North Sea) in May 2013 and March 2015. The investigated area is characterized by heterogeneously distributed moraine deposits and rippled coarse sediments partly draped with Holocene fine sands. The relict sediments and the rippled coarse sediments indicate both high backscatter intensities but can be distinguished by means of the hyperbola locations. The northeast of the study area is dominated by rippled coarse sediments (without hyperbolas) and the southwestern part by relict sediments with a high amount of stones represented by hyperbolas which is also proven by extensive ground-truthing (grab sampling and high quality underwater videos). An automated procedure to identify and export the hyperbola positions makes the demarcation of hard substrate grounds (here: relict sediments) reproducible, faster and less complex in comparison to the visual-manual identification on the basis of sidescan sonar data.

  2. Estuarine circulation reversals and related rapid changes in winter near-bottom oxygen conditions in the Gulf of Finland, Baltic Sea

    Directory of Open Access Journals (Sweden)

    T. Liblik

    2013-04-01

    Full Text Available The reversal of estuarine circulation caused by southwesterly wind forcing may lead to vanishing of stratification and oxygenation of deep layers during the cold season in the Gulf of Finland. Six CTD + oxygen transects (130 km long, 10 stations were conducted along the thalweg from the western border to the central gulf (21 December 2011–8 May 2012. Two bottom-mounted ADCP, near the western border and in the central gulf were installed. A CTD with dissolved oxygen sensor was deployed close to the western ADCP. Periods with typical estuarine circulation were characterized by strong stratification; high salinity, hypoxic conditions and inflow to the gulf in the near bottom layer. Two circulation reversals were observed, in December–January and February–March. The first well-developed reversal event caused the vanishing of stratification and oxygen concentrations that were almost over 270 μmol L−1 (6 mL L−1 in the entire water column along the transect; and lasted for about 1.5 months. Shifts from estuarine circulation to reversed circulation and vice versa were both associated with strong currents (up to 40 cm s−1 in the deep layer. In the western area of study, near-bottom oxygen conditions strongly depended on salt wedge intrusions (hypoxic water from the NE Baltic Proper, while in the eastern part good oxygen conditions caused by reversals remained for a few months. Change from oxygenated to hypoxic conditions in the entrance area to the Gulf might occur very rapidly, within less than a day.

  3. Dynamics of REE accumulation and fractionation in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section, Sea of Japan

    Science.gov (United States)

    Polyakov, D. M.

    2016-05-01

    The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.

  4. Osnovnye zakonomernosti raspredelenija, migracii i nakoplenija radionuklidov v donnyh otlozhenijah Baltijskogo morja [The basic patterns of the distribution, migration and accumulation of radionuclides in the bottom sediment of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Grigoryev Andrey

    2011-01-01

    Full Text Available This paper focuses on the impact of certain factors on the contemporary distribution of natural (226Ra, 232Th, 40К and anthropogenic (137Cs, 60Co radionuclides in the sediments of the Baltic Sea. The results of the study suggest that the distribution of 137Cs is determined by the content of hydromica of silty-clay and clay grain-size fractions, while radiocaesium is mainly accumulated by silty fractions. The accumulation of 226Ra by bottom sediments is mainly determined by the pH geochemical barrier at the water-seafloor boundary. The accumulation of 232Th occurs mainly in clayey fractions of the sediment. The distribution and accumulation of 40K is predominantly determined by the ratio of potassium contained in hydromica minerals. Significant 60Co activity was registered only in a few samples.

  5. Estuarine circulation reversals and related rapid changes in winter near-bottom oxygen conditions in the Gulf of Finland, Baltic Sea

    Directory of Open Access Journals (Sweden)

    T. Liblik

    2013-10-01

    Full Text Available The reversal of estuarine circulation caused by southwesterly wind forcing may lead to vanishing of stratification and subsequently to oxygenation of deep layers during the winter in the Gulf of Finland. Six conductivity, temperature, depth (CTD+oxygen transects (130 km long, 10 stations were conducted along the thalweg from the western boundary to the central gulf (21 December 2011–8 May 2012. Two bottom-mounted ADCP were installed, one near the western border and the second in the central gulf. A CTD with a dissolved oxygen sensor was deployed close to the western ADCP. Periods of typical estuarine circulation were characterized by strong stratification, high salinity, hypoxic conditions and inflow to the gulf in the near-bottom layer. Two circulation reversals were observed: one in December–January and one in February. The first reversal event was well developed; it caused the disappearance of the stratification and an increase in the oxygen concentration from hypoxic values to 270 μmol L−1 (to 6 mL L−1 throughout the water column along the thalweg and lasted approximately 1.5 months. Shifts from estuarine circulation to reversed circulation and vice versa were both associated with strong longitudinal (east–west gulf currents (up to 40 cm s−1 in the deep layer. The change from oxygenated to hypoxic conditions in the western near-entrance area of the gulf occurred very rapidly, within less than a day, due to the intrusion of the hypoxic salt wedge from the NE Baltic Proper. In the eastern part of the gulf, good oxygen conditions caused by reversals remained for a few months.

  6. Population structure and feeding ecology of the bat star Asterina stellifera (Möbius, 1859): Omnivory on subtidal rocky bottoms of temperate seas

    Science.gov (United States)

    Farias, Nahuel E.; Meretta, Pablo E.; Cledón, Maximiliano

    2012-05-01

    During four years we surveyed the southernmost population of the sea star Asterina stellifera, which has been declared endangered in the central and northern parts of its distribution, and studied their feeding ecology by in situ observations and a short-term manipulative experiment. Contrary to our expectation we found abundant populations with densities up to 72 ind.m- 2. The individuals grew slowly over four years with no replacement in the smaller size classes. In the short term, presence of A. stellifera negatively impacted the abundance of all macrobenthic species analyzed, including sessile and moving animals and algae. We demonstrate that this sea star feeds in a non-selective way on several items belonging to different trophic levels. In addition, it displays a microphagous feeding behavior, so its direct impact might extend to settlers, modifying the recruitment of benthic populations. Indirect effects were not detected, likely due to the experiments lasting for a very short period. As an abundant omnivore, A. stellifera is likely affecting the stability of trophic webs of which they are part.

  7. Time stability of ocean bottom seismometers (OBS)

    OpenAIRE

    Shariat Panahi, Shahram; Manuel Lázaro, Antonio; Corrêa Alegría, Francisco

    2010-01-01

    During the past decades, Ocean Bottom Seismometers (OBS) have played a key role in permanent seismic activity monitoring at sea as well as allowing a better understating of the earth interior. Data collected by the instrument can provide information on the ocean bottom sub-layers down to a depth of 40 km beneath the ocean floor. The accuracy of the results directly depends on the temperature stability of the crystal used as the main time base of the equipment. This paper pre...

  8. 渤黄东海底摩擦系数数值研究%Numerical Study on the Bottom Friction Coefficient of the Bohai, Yellow and East China Seas

    Institute of Scientific and Technical Information of China (English)

    张继才; 祝建国; 吕咸青

    2006-01-01

    使用伴随同化方法探讨了四种底摩擦系数处理方法并模拟了渤黄东海的M2分潮.理想实验表明:伴随同化方法有很强的反演底摩擦系数的能力;为了得到较好的反演结果,反演策略必须与给定的分布一致;如果给定分布很复杂,则需要复杂的反演策略.实际实验表明,底摩擦效应与地形密切相关,而海洋地形十分复杂,故需要较多的独立的底摩擦系数才能得到较好的模拟结果.本文的第四种方法将每一点均作为独立的底摩擦系数,在实验中获得了成功,验证了这种方法的合理性和有效性.%Based on the simulation of the M2 tide in the Bohai, Yellow and East China Seas, numerical experiments are made to study 4 strategies on the bottom friction coefficient (BFC) in a numerical adjoint model. In order to make a better simulation, the strategy must be consistent with the given BFC distribution. The real bottom friction decided by ocean topography is very complicated and an independent BFC is required. The fourth method which takes the BFC in each grid point as an independent BFC simulates practical experiments best and demonstrates the reasonability and efficiency of this method.

  9. Sink or swim: Updated knowledge on marine fungi associated with wood substrates in the Mediterranean Sea and hints about their potential to remediate hydrocarbons

    Science.gov (United States)

    Garzoli, Laura; Gnavi, Giorgio; Tamma, Federica; Tosi, Solveig; Varese, Giovanna C.; Picco, Anna M.

    2015-09-01

    This paper provides the first update in more than twenty years on the available knowledge about lignicolous marine fungi in the Mediterranean Sea. Fungi found on collected wood samples were analyzed using a combination of morphological and molecular techniques. Almost 90% of the samples were colonized by fungi. The total number of recorded taxa, which amounted to 57 in the late 1990s, has now risen to 93. Wood-inhabiting marine fungi are good producers of ligninolytic enzymes, which can degrade several aromatic and recalcitrant environmental pollutants. In light of bioremediation technologies, this study also evaluated the potential of the isolated strains to remediate complex hydrocarbon substrates. Seventeen isolates were shown to be able to grow on hydrocarbon media as a sole carbon source; enhanced performances were achieved in the presence of NaCl, suggesting that these fungi adapt well to marine conditions and confirming that salt can trigger specific metabolic pathways in marine fungi.

  10. Bottom Sediments -- Cape Ann to Casco Bay (FOLGER75 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The reconnaissance maps upon which this data set is based show the areal distribution of the major bottom sediment types covering the sea floor off eastern New...

  11. Integrated hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter, World-View 2 imagery and bathymetry derivatives of Ni'ihau Island, Hawaii, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter, bathymety derivatives, and bathymetry derived...

  12. Preliminary hard and soft bottom seafloor substrate map (5m grid) derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Rose Atoll Lagoon, Territory of American Samoa, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymetry derivatives at Rose Atoll...

  13. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Saipan Island, Commonwealth of the Northern Mariana Islands (CNMI).

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Saipan Island,...

  14. Preliminary hard and soft bottom seafloor substrate map derived from an supervised classification of bathymetry derived from multispectral World View-2 satellite imagery of Ni'ihau Island, Territory of Main Hawaiian Islands, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from a supervised classification from multispectral World View-2 satellite imagery of Ni'ihau Island,...

  15. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Tinian Island, Commonwealth of the Northern Mariana Islands (CNMI).

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Tinian Islands...

  16. Preliminary hard and soft bottom seafloor substrate map derived from an unsupervised classification of gridded backscatter and bathymetry derivatives at Pagan Island, Commonwealth of the Northern Mariana Islands (CNMI).

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary hard and soft seafloor substrate map derived from an unsupervised classification of multibeam backscatter and bathymety derivatives at Pagan Island,...

  17. Microbial Sulfate Reduction in Deep-Sea Sediments at the Guaymas Basin - Hydrothermal Vent Area - Influence of Temperature and Substrates

    DEFF Research Database (Denmark)

    ELSGAARD, L.; ISAKSEN, MF; JØRGENSEN, BB;

    1994-01-01

    Microbial sulfate reduction was studied by a S-35 tracer technique in sediments from the hydrothermal vent site in Guaymas Basin, Gulf of California, Mexico. In situ temperatures ranged from 2.7-degrees-C in the overlying seawater to > 120-degrees-C at 30 cm depth in the hydrothermal sediment......-1 at 70-degrees-C. The rates of sulfate reduction rapidly decreased with depth in the upper 0- 10 cm of the sediment and the maximal depth-integrated rate (0-10 cm) was 70.3 mmol SO42- m-2 d-1 at 70-degrees-C. In comparison, the sulfate reduction rate in nonhydrothermal sediment from the vent area...... was 0.85 mmol m-2 d-1 at the in situ temperature of about 3-degrees-C. The high subsurface rates of sulfate reduction in the hydrothermal vent area was attributed to an enhanced local substrate availability. In slurries of hydrothermal sediment, incubated at 10-120-degrees-C, microbial sulfate reduction...

  18. Integrated hard and soft bottom seafloor substrate map of Ofu-Olosega, American Samoa, combining NOAA Pacific Island Fisheries Science Center Coral Reef Ecosystem Division hard-soft substrate map with NOAA Center for Coastal Monitoring and Assessment Biogeography Program shallow-water benthic habitat map of American Samoa.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hard and soft seafloor substrate map, derived from integrating two existing map products: hard and soft seafloor substrate map derived from an unsupervised...

  19. Integrated hard and soft bottom seafloor substrate map of Ta'u, American Samoa, combining NOAA Pacific Island Fisheries Science Center Coral Reef Ecosystem Division hard-soft substrate map with NOAA Center for Coastal Monitoring and Assessment Biogeography Program shallow-water benthic habitat map of American Samoa.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hard and soft seafloor substrate map, derived from integrating two existing map products: hard and soft seafloor substrate map derived from an unsupervised...

  20. Integrated hard and soft bottom seafloor substrate map of Rose Atoll, American Samoa combining NOAA Pacific Island Fisheries Science Center Coral Reef Ecosystem Division hard-soft substrate maps with NOAA Center for Coastal Monitoring and Assessment Biogeography Program shallow-water benthic habitat map of American Samoa.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hard and soft seafloor substrate map, derived from integrating two existing map products: hard and soft substrate maps derived from an unsupervised classification...

  1. A facies distribution model controlled by a tectonically inherited sea bottom topography in the carbonate rimmed shelf of the Upper Tithonian-Valanginian Southern Tethyan continental margin (NW Sicily, Italy)

    Science.gov (United States)

    Basilone, Luca; Sulli, Attilio

    2016-08-01

    The Upper Tithonian-Valanginian shallow-water carbonates outcropping in the Palermo Mts (NW Sicily) consist of several facies associations reflecting different depositional environments of a carbonate rimmed shelf, pertaining to the Southern Tethyan continental margin. The reconstructed depositional model, based on the sedimentological features, cyclic facies arrangement and biota distribution, shows that a wide protected lagoon, dominated by algae, molluscs and scattered patch reefs, was bordered landward by a tidal flat, where stromatolitic algal mats were cyclically subaerial exposed, and seaward by a marine sand belt and reef complex. Oolitic packstone-grainstone lithofacies, cyclically subjected to subaerial exposure, suggests the occurrence of a barrier island, located nearly to the lagoonal carbonate shoreline, allowing the development of narrow embayments with restricted circulation. In the outer platform, the oolitic lithofacies of the marine sand belt pass landward into the protected lagoon, where washover oolite sands occur, and seaward into a high-energy zone (back-reef apron) gradually merging in the reef complex. In the latter, coral framestone occupied the inner sector (reef flat), while the facies association dominated by boundstone with Ellipsactinia sp. developed in the outer sectors (reef wall), adjacent to the fore-reef and upper slope environments. Stratigraphic evidence, associated with the recognized facies associations, helped to reconstruct the geo-tectonic setting of the carbonate platform, where the distribution of the depositional facies along the shelf and their extension were influenced by the tectonically-inherited sea bottom topography. In a regime of extensional tectonics, localized and thin succession of high-energy prograding oolite sand belt depositional facies occupied structural highs (footwall uplift), while the largely diffused and thick low energy aggrading peritidal-to-lagoonal depositional facies developed in subsiding

  2. Spring Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Spring Bottom Trawl Survey was initiated in 1968 and covered an area from Cape Hatteras, NC, to Nova Scotia, Canada, at depths >27m....

  3. Winter Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Winter Bottom Trawl Survey was initiated in 1992 and covered offshore areas from the Mid-Atlantic to Georges Bank. Inshore strata were...

  4. Fall Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years,...

  5. Summer Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sampling the coastal waters of the Gulf of Maine using the Northeast Fishery Science Center standardized bottom trawl has been problematic due to large areas of...

  6. Cuttlefish Sepia officinalis Preferentially Respond to Bottom Rather than Side Stimuli When Not Allowed Adjacent to Tank Walls.

    Directory of Open Access Journals (Sweden)

    Darcy A A Taniguchi

    Full Text Available Cuttlefish are cephalopods capable of rapid camouflage responses to visual stimuli. However, it is not always clear to what these animals are responding. Previous studies have found cuttlefish to be more responsive to lateral stimuli rather than substrate. However, in previous works, the cuttlefish were allowed to settle next to the lateral stimuli. In this study, we examine whether juvenile cuttlefish (Sepia officinalis respond more strongly to visual stimuli seen on the sides versus the bottom of an experimental aquarium, specifically when the animals are not allowed to be adjacent to the tank walls. We used the Sub Sea Holodeck, a novel aquarium that employs plasma display screens to create a variety of artificial visual environments without disturbing the animals. Once the cuttlefish were acclimated, we compared the variability of camouflage patterns that were elicited from displaying various stimuli on the bottom versus the sides of the Holodeck. To characterize the camouflage patterns, we classified them in terms of uniform, disruptive, and mottled patterning. The elicited camouflage patterns from different bottom stimuli were more variable than those elicited by different side stimuli, suggesting that S. officinalis responds more strongly to the patterns displayed on the bottom than the sides of the tank. We argue that the cuttlefish pay more attention to the bottom of the Holodeck because it is closer and thus more relevant for camouflage.

  7. The complex influences of back-barrier deposition, substrate slope and underlying stratigraphy in barrier island response to sea-level rise: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, U.S.A.

    Science.gov (United States)

    Brenner, Owen T.; Moore, Laura J.; Murray, A. Brad

    2015-10-01

    To understand the relative importance of back barrier environment, substrate slope and underlying stratigraphy in determining barrier island response to RSLR (relative sea-level rise), we use a morphological-behavior model (GEOMBEST) to conduct a series of sensitivity experiments, based on late-Holocene hindcast simulations of an island in the U.S. mid-Atlantic Bight (Metompkin Island, VA) having both salt marsh and lagoonal back-barrier environments, and we draw comparisons between these results and future simulations (2000-2100 AD) of island response to RSLR. Sensitivity analyses indicate that, as a whole, the island is highly sensitive to factors that reduce overall sand availability (i.e., high sand-loss rates and substrates containing little sand). Results also indicate that for all predicted future RSLR scenarios tested, islands having high substrate sand proportions (if allowed to migrate freely) will likely remain subaerial for centuries because of sufficient substrate sand supply and elevation to assist in keeping islands above sea level. Simulation results also lead to basic insights regarding the interactions among substrate slope, back-barrier deposition and island migration rates. In contrast to previous studies, which suggest that changes in substrate slope directly affect the island migration trajectory, we find that-in the presence of back-barrier deposition-the connection between substrate slope and island behavior is modulated (i.e., variability in migration rates is dampened) by changes in back-barrier width. These interactions-which tend to produce changes in shoreface sand content-lead to a negative feedback when the back-barrier deposit contains less sand than the underlying layer, resulting in a stable back-barrier width. Alternatively, a positive feedback arises when the back-barrier deposit contains more sand than the underlying layer, resulting in either back-barrier disappearance or perpetual widening.

  8. Bottom hadrons from lattice QCD with domain wall and NRQCD fermions

    Energy Technology Data Exchange (ETDEWEB)

    Stefan Meinel, William Detmold, C.-J. David Lin, Matthew Wingate

    2009-07-01

    Dynamical 2+1 flavor lattice QCD is used to calculate the masses of bottom hadrons, including B mesons, singly and doubly bottom baryons, and for the first time also the triply-bottom baryon Omega{sub bbb}. The domain wall action is used for the up-, down-, and strange quarks (both valence and sea), while the bottom quark is implemented with non-relativistic QCD. A calculation of the bottomonium spectrum is also presented.

  9. Time base stability of ocean bottom seismometers (OBS)

    OpenAIRE

    Shariat Panahi, Shahram; Manuel Lázaro, Antonio; Corrêa Alegría, Francisco

    2009-01-01

    During the past decades, Ocean Bottom Seismometers (OBS) have played a key role in permanent seismic activity monitoring at sea as well as allowing a better understating of the earth interior. Data collected by the instrument can provide information on the ocean bottom sub-layers down to a depth of 40 km beneath the ocean floor. The accuracy of the results directly depends on the temperature stability of the crystal used as the main time base of the equipment. This paper pre...

  10. NPRB 1117 Cooperative research to develop new trawl footrope designs to reduce mortality of southern Tanner and snow crabs (Chionoecetes bairdi and C. opilio) incidental to Bering Sea bottom trawl fisheries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Alaska’s Bering Sea is home to some of the world’s most productive groundfish and crab stocks and the fisheries that depend on them. Their spatial overlap creates...

  11. SIMULATION STUDY OF IMAGING OF UNDERWATER BOTTOM TOPOGRAPHY BY SYNTHETIC APERTURE RADAR

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Interaction between current and underwater bottom topography modulates roughness of the sea surface, which in turn yields variation of the radar scattering echo. By using the mechanism, this paper presents a simulation model for Synthetic Aperture Radar (SAR) imaging of underwater bottom topography. The numerical simulations experiments were made using the Princeton Ocean Model (POM) and analytical expression theory of SAR Image in Mischief sea area. It is concluded that the SAR image is better visual when water depth of underwater bottom topography is shallow or gradient of underwater bottom topography is high.

  12. Late Quaternary spatial and temporal variability in Arctic deep-sea bioturbation and its relation to Mn cycles

    OpenAIRE

    Löwemark, Ludvig; Hanebuth, T J J; O'Regan, M.; Jakobsson, M.

    2012-01-01

    Changes in intensity and composition of bioturbation and trace fossils in deep-sea settings are directly related to changes in environmental parameters such as food availability, bottom water oxygenation, or substrate consistency. Because trace fossils are practically always preserved in situ, and are often present in environments where other environmental indicators are scarce or may have been compromised or removed by diagenetic processes, the trace fossils provide an important ...

  13. Decapod crustaceans associated with an artificial reef (Adriatic Sea

    Directory of Open Access Journals (Sweden)

    A. SANTELLI

    2013-07-01

    Full Text Available The aim of this study is to increase the knowledge on the distribution of decapod crustaceans associated with an artificial reef positioned on sandy-mud bottoms in the central Adriatic Sea. The reef is constituted of concrete modules assembled in pyramids and concrete poles. Hard and soft bottom samples were collected from 2001, just after reef construction, to 2005 (4 surveys per year. Regarding the soft seabed, three sites close to a pyramid, three inside the reef area at a distance of 10-15 m from the structures, and three 200 m outside the reef (control sites were randomly sampled during each survey. At the same time, three pyramids (vertical and horizontal walls and three poles were also investigated. After taxonomical analysis, decapod crustaceans were analysed using abundance and species richness. Sites and years were compared using a balanced, fixed effect, 2-way ANOVA and PERMANOVA. In addition, SIMPER analysis was performed to identify those species typifying each community inhabiting both the soft bottom and the artificial substrates. The results showed that the artificial reef induced an increase in both abundance and diversity of the decapods of the natural habitat. In fact, man-made substrates may offer new available space for biological colonization and allow the settlement of new species usually living on hard bottoms, thus increasing the complexity of the original benthic communities.

  14. A Can of Sea Worms

    Science.gov (United States)

    Zinn, Donald J.

    1977-01-01

    A comprehensive discussion of the free-living worms that inhabit the beaches and subtidal bottoms of the Cape Cod shoreline is presented. Methods for the location, collection, preservation, and identification of sea worms are identified. (BT)

  15. Data acquisition system for a cabled ocean bottom seismometer (OBS)

    OpenAIRE

    Rogalski, Tomasz; Shariat Panahi, Shahram; Río Fernandez, Joaquín del; Manuel Lázaro, Antonio

    2010-01-01

    Ocean Bottom Seismometers (OBS) are highly used to monitor seismic activities at sea. They are also used to detect tsunamis and generate warning alarms. This paper presents a data acquisition system built for an OBS with capability to synchronize time through IEEE-1588 protocol. This acquisition system provides real time data through the Ethernet making it suitable for OBSs deployed at seafloor observatories.

  16. Species sorting during biofilm assembly by artificial substrates deployed in a cold seep system

    KAUST Repository

    Zhang, Wei Peng

    2014-10-17

    Studies focusing on biofilm assembly in deep-sea environments are rarely conducted. To examine the effects of substrate type on microbial community assembly, biofilms were developed on different substrates for different durations at two locations in the Red Sea: in a brine pool and in nearby bottom water (NBW) adjacent to the Thuwal cold seep II. The composition of the microbial communities in 51 biofilms and water samples were revealed by classification of pyrosequenced 16S rRNA gene amplicons. Together with the microscopic characteristics of the biofilms, the results indicate a stronger selection effect by the substrates on the microbial assembly in the brine pool compared with the NBW. Moreover, the selection effect by substrate type was stronger in the early stages compared with the later stages of the biofilm development. These results are consistent with the hypotheses proposed in the framework of species sorting theory, which states that the power of species sorting during microbial community assembly is dictated by habitat conditions, duration and the structure of the source community. Therefore, the results of this study shed light on the control strategy underlying biofilm-associated marine fouling and provide supporting evidence for ecological theories important for understanding the formation of deep-sea biofilms.

  17. Bottom sediments affect Sonneratia mangrove forests in the prograding Mekong delta, Vietnam

    Science.gov (United States)

    Nardin, William; Woodcock, Curtis E.; Fagherazzi, Sergio

    2016-08-01

    Mangrove forests exert a strong influence on tropical deltas by trapping sediments discharged by rivers and by stabilizing the substrate with roots. Understanding the dynamics of sediments and morphology in and around mangrove forests is critical in order to assess the resilience of coastlines in a period of accelerated sea level rise. In this research, sediment samples, mangrove forest characteristics, and remote sensing data are used to investigate the relationship between mangroves and sediment substrate in the Mekong Delta, Vietnam. Our data show a significant correlation between percent of sand in bottom sediments and density of Sonneratia caseolaris forest. We ascribe this result to higher sediment disturbance in muddy areas that prevents seedling establishment. This correlation potentially allows the determination of substrate characteristics from vegetation attributes detected by remote sensing, despite the impenetrability of the forest canopy. The results presented herein suggest that a supply of sand from the river and hydrodynamic processes moving the sand ashore control the density of the Sonneratia mangrove forests at this location, promoting tidal flat colonization and canopy expansion.

  18. Effect of bottom cell properties on micromorph tandem device performance

    OpenAIRE

    Delli Veneri, Paola; Mercaldo, Lucia Vittoria; PRIVATO Carlo

    2009-01-01

    Abstract Micromorph tandem solar cells represent an elegant way of overcoming the efficiency limits of single-junction solar cells and reducing the light-induced degradation of amorphous silicon films. Micromorph devices have been realized on Asahi U-type TCO-covered glass substrates by very high frequency plasma enhanced chemical vapour deposition (VHF-PECVD) at 100 MHz at low substrate temperature (150 ?C). For the bottom cell different growth regimes have been explored by changi...

  19. 新型海底释放器释放机构的可靠性及其动态特性研究%Reliability and Dynamic Analysis on the New Release Device in the Bottom of Sea

    Institute of Scientific and Technical Information of China (English)

    张庆力; 张开升; 刘风

    2013-01-01

    根据海水等静压技术设计新型释放器的释放机构,利用FEMAP有限元分析软件分析钢球与释放器连接套的接触变形,对释放机构的可靠性进行分析,找出释放机构参数确定的方法;利用仿真的方法得到了释放机构释放的运动特性。%The new submarine releaser sea was designed using deep iso-static pressing technology .The contact deformation between ball and contacted set was analyzed by FEMAP to research their reliability .The methods of determining the release mechanism parameters were found .The motion characteristics of the release mechanism were gotten by simulation .

  20. Area-intensive bottom culture of blue mussels Mytilus edulis in a micro-tidal estuary

    DEFF Research Database (Denmark)

    Dolmer, Per; Christensen, Helle Torp; Hansen, Benni Winding;

    2012-01-01

    Dredge fishery for blue mussels Mytilus edulis (L.) impacts the benthic ecosystem, and substitution by area-intensive bottom culture production may reduce adverse effects on the ecosystem. Two different field studies in 2007 and 2009 tested the productivity of bottom culture of blue mussels......, and whether a shift from dredging of full-grown blue mussels to production of blue mussels in bottom culture could reduce the area of impacted sea bottom. In the first study, the macrostructure of a commercial bottom culture was analysed by side scan mapping, and the growth of blue mussels was recorded...... on a transect from the edge to the central part of the bottom culture. In the second study, we analysed the effect of seeding density (1.5 and 3.5 kg m−2) on mussel production. The measured production was used to model the affected area when producing blue mussels in bottom culture. The macrostructure...

  1. In situ experimentation at the water/sediment interface in the deep sea: 2. Biotransformation of dissolved organic substrates by microbial communities at 2000m depth in the Bay of Biscay

    Science.gov (United States)

    Cahet, Guy; Daumas, Raoul; Sibuet, Myriam

    Few attempts have been made to quantify the utilization of organic matter by the bacteria of the superficial layers of deep sea sediment. During two BIOCYAN cruises (August 1986 and June 1987) we used the submersible Cyana, to incubate sediment samples in situ in a specially designed box core in presence of 14C-glutamic acid and 3H leucine. These experiments were conducted at 2000m depth in the Bay of Biscay. Bacterial activity was stopped by the injection of formaldehyde. Samples were retrieved with the research submersible Cyana and its accompanying free vehicle shuttle. Sediment organic matter was fractioned into four components: 1) 14CO 2; 2) nucleic components and polysacharids; 3) labile proteins; and 4) condensed hydrolysable polymers. To evaluate the barotolerance of deep-sea bacteria, undisturbed superficial layer samples were also incubated with the same labelled substrates at 4°C at the atmospheric pressure. In both cases, and except for glucose, our results show that distributions of radioactivity in the different components of the organic material were almost similar. However, the rate of incorporation was usually higher for in situ experiments than for decompressed samples. Bacterial utilization of both 14C glutamic acid and 14C glucose were higher in June than in August. Such differences may result from changes in the food supply arriving as sinking particles and deriving from the photosynthetically productive surface waters. Food input was probably more important in June than in August leading to corresponding increases in: 1) the abundance of derived bacteria, and 2) deep-sea bacterial activities.

  2. Postglacial floodings of the Marmara Sea: molluscs and sediments tell the story

    Science.gov (United States)

    Büyükmeriç, Yeşim

    2016-08-01

    The early Holocene marine flooding of the Black Sea has been the subject of intense scientific debate since the "Noah's Flood" hypothesis was proposed in the late 1990s. The chronology of the flooding is not straightforward because the connection between the Black Sea and the Mediterranean Sea involves the intermediate Marmara Sea Basin via two sills (Dardanelles and Bosphorus). This study explores the chronology of late Pleistocene-Holocene flooding by examining sedimentary facies and molluscs from 24 gravity cores spanning shelf to slope settings in the southern Marmara Sea Basin. A late Pleistocene Ponto-Caspian (Neoeuxinian) mollusc association is found in 12 of the cores, comprising 14 mollusc species and dominated by brackish (oligohaline-lower mesohaline) endemic taxa (dreissenids, hydrobiids). The Neoeuxinian association is replaced by a Turritella- Corbula association at the onset of the Holocene. The latter is dominated by marine species, several of which are known to thrive under dysoxic conditions in muddy bottoms. This association is common in early Holocene intervals as well as sapropel intervals in younger Holocene strata. It is an indicator of low-salinity outflows from the Black Sea into the Marmara Sea that drive stratification. A marine Mediterranean association (87 species) represents both soft bottom and hard substrate faunas that lived in well-ventilated conditions and upper mesohaline-polyhaline salinities (ca. 25 psu). Shallower areas were occupied by hard substrate taxa and phytopdetritic communities, whereas deeper areas had soft bottom faunas. The middle shelf part of the northern Gemlik Gulf has intervals with irregular and discontinuous sedimentary structures admixed with worn Neoeuxinian and euryhaline Mediterranean faunas. These intervals represent reworking events (slumping) likely related to seismic activity rooted in the North Anatolian Fault system. The core data and faunas indicate an oscillating postglacial sea-level rise and

  3. Natural variability in hard-bottom communities and possible drivers assessed by a time-series study in the SW Baltic Sea: know the noise to detect the change

    Directory of Open Access Journals (Sweden)

    M. Wahl

    2013-07-01

    Full Text Available In order to detect shifts in community structure and function associated with global change, the natural background fluctuation in these traits must be known. In a 6 yr study we characterized the composition of young benthic communities at 7 sites along the 300 km coast of the Kiel and Lübeck bights in the German Baltic Sea and we quantified their interannual variability of taxonomic and functional composition. Along the salinity gradient from NW to SE, the relative abundance of primary producers decreased while that of heterotrophs increased. Along the same gradient, annual productivity tended to increase. Taxonomic and functional richness were higher in Kiel Bight as compared to Lübeck Bight. With increasing species richness functional group richness showed saturation indicating an increasing functional redundancy in species rich communities. While taxonomic fluctuations between years were substantial, functionality of the communities seem preserved in most cases. Environmental conditions potentially driving these fluctuations are winter temperatures and current regimes. We tentatively define a confidence range of natural variability in taxonomic and functional composition a departure from which might help identifying an ongoing regime shift driven by global change. In addition, we propose to use RELATE, a statistical procedure in the PRIMER (Plymouth Routines in Multivariate Ecological Research package to distinguish directional shifts in time ("signal" from natural temporal fluctuations ("noise".

  4. Remote Sensing of shallow sea floor for digital earth environment

    International Nuclear Information System (INIS)

    Understanding the sea floor biodiversity requires spatial information that can be acquired from remote sensing satellite data. Species volume, spatial patterns and species coverage are some of the information that can be derived. Current approaches for mapping sea bottom type have evolved from field observation, visual interpretation from aerial photography, mapping from remote sensing satellite data along with field survey and hydrograhic chart. Remote sensing offers most versatile technique to map sea bottom type up to a certain scale. This paper reviews the technical characteristics of signal and light interference within marine features, space and remote sensing satellite. In addition, related image processing techniques that are applicable to remote sensing satellite data for sea bottom type digital mapping is also presented. The sea bottom type can be differentiated by classification method using appropriate spectral bands of satellite data. In order to verify the existence of particular sea bottom type, field observations need to be carried out with proper technique and equipment

  5. Bottom sediments of Ypacarai Lake

    International Nuclear Information System (INIS)

    Bottom sediments of Ypacarai Lake was investigated with XRF and Mossbauer techniques. The lake of about 120 Km2, is a shallow one, medium deep of about 1.8m. In addition to its use for recreation, its basin has a wide area of influence and of economical significance. Bottom sediments play an important role in the overall distribution of trace elements in the aquatic system and act as a sink for metals. Bottom samples were taken from 5 different sampling stations, selected according to the morphology and population sites in the shore. The concentration of toxic metals was found to be low and no negative ecological impact should be expected. The main metallic ion component is iron (1.69%). Mossbauer studies showed this element appears as Fe+3 and no Fe+2 was detected. It is here suggested that Fe+3 acts as the limiting element which controls eutrophication process

  6. Bottomed analog of Z+(4433)

    International Nuclear Information System (INIS)

    The newly observed Z+(4433) resonance by BELLE is believed to be a tetraquark bound state made up of (cu)(cd). We propose the bottomed analog of this bound state, namely, by replacing one of the charm quarks by a bottom quark, thus forming Zbc0,±,±±. One of the Zbc is doubly charged. The predicted mass of Zbc is around 7.6 GeV. This doubly charged bound state can be detected by its decay into Bc±π±. Similarly, we can also replace both charm quark and antiquark of the Z+(4433) by bottom quark and antiquark, respectively, thus forming Zbb the bottomonium analog of Z+(4433). The predicted mass of Zbb is about 10.7 GeV

  7. The impact of bottom brightness on spectral reflectance of suspended sediments

    Science.gov (United States)

    Tolk, Brian L.; Han, L.; Rundquist, D. C.

    2000-01-01

    Two experiments were conducted outdoors to investigate how bottom brightness impacts the spectral response of a water column under varied suspended sediment concentrations. A white aluminum panel placed at the bottom of the tank was used as the bright bottom, and a flat-black tank liner served as the dark bottom. Sixteen levels of suspended sediment from 25 to 400 mg litre -1 were used in each experiment. Spectral data were collected using a Spectron SE-590 spectroradiometer. The major findings include the following: the bright bottom had the greatest impact at visible wavelengths; when suspended sediment concentrations exceeded 100 mg litre -1, the bright bottom response was found to be negligible; and, substrate brightness has minimal impact between 740 and 900 nm, suggesting that these wavelengths are best for measuring suspended sediment concentrations by means of remote sensing.

  8. Offshore Substrate

    Data.gov (United States)

    California Department of Resources — This shapefile displays the distribution of substrate types from Pt. Arena to Pt. Sal in central/northern California. Originally this data consisted of seven paper...

  9. Culture from the Bottom Up

    Science.gov (United States)

    Atkinson, Dwight; Sohn, Jija

    2013-01-01

    The culture concept has been severely criticized for its top-down nature in TESOL, leading arguably to its falling out of favor in the field. But what of the fact that people do "live culturally" (Ingold, 1994)? This article describes a case study of culture from the bottom up--culture as understood and enacted by its individual users.…

  10. EFFECTS OF WAVE-CURRENT INTERACTIONS ON BOTTOM STRESS AND CURRENTS

    Institute of Scientific and Technical Information of China (English)

    Yin Bao-shu; Yang De-zhou; Lin Xiang; Hou Yi-jun; Cheng Ming-hua; Will Perrie

    2003-01-01

    This paper presents a high-resolution (2′×2′) numerical model of coastal coupled wave-current interaction with explicit consideration of the effects of wave-current interaction on bottom stress. For two selected storms with measured data in the Yellow River coastal area of the Bohai Sea, it is shown that the bottom stress calculated by using a coupled wave-current model is increased, as one would expect, compared with the bottom stress computed with an uncoupled current model. Moreover, the current velocity field is also changed, but the corresponding current directions show less influence in the two simulations. The extents of changes in bottom stress and current velocity vary with storm intensities. The results further imply that the coupled wave-current model should be used as the basis for simulating the current velocity and sea level in the near shore region.

  11. DMSP and DMS cycling within Antarctic sea ice during the winter-spring transition

    Science.gov (United States)

    Damm, E.; Nomura, D.; Martin, A.; Dieckmann, G. S.; Meiners, K. M.

    2016-09-01

    This study describes within-ice concentrations of dimethylsulfoniopropionate (DMSP), its degradation product dimethylsulphide (DMS), as well as nutrients and chlorophyll a, that were sampled during the Sea Ice Physics and Ecosystems eXperiment-2 (SIPEX-2) in 2012. DMSP is a methylated substrate produced in large amounts annually by ice-associated microalgae, while DMS plays a significant role in carbon and sulphur cycling in the Southern Ocean. In the East Antarctic study area between 115-125°E and 64-66°S, ice and slush cores, brine, under-ice seawater and zooplankton (Antarctic krill) samples were collected at 6 ice stations. The pack-ice was characterised by high snow loading which initiated flooding events and triggered nutrient supply to the sea-ice surface, while variation in ice conditions influenced sea-ice permeability. This ranged from impermeable surface and middle sections of the sea ice, to completely permeable ice cores at some stations. Chlorophyll a maxima shifted from the sea-ice surface horizon at the first station to the sea ice bottom layer at the last station. Highest DMSP concentrations were detected in brine samples at the sea-ice surface, reflecting a mismatch with respect to the distribution of chlorophyll a. Our data suggest enhanced DMSP production by sea-ice surface algal communities and its release into brine during freezing and melting, which in turn is coupled to flooding events early in the season. A time-cycle of DMS production by DMSP degradation and DMS efflux is evident at the sea ice-snow interface when slush is formed during melt. Seawater under the ice contained only low concentrations of DMSP and DMS, even when brine drainage was evident and the sea ice became permeable. We postulate that in situ grazing by zooplankton may act as sink for the DMSP produced early in the season.

  12. Reconstructing bottom water temperatures from measurements of temperature and thermal diffusivity in marine sediments

    OpenAIRE

    F. Miesner; Lechleiter, A.; Müller, C.(Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, Sternwartstr. 7, 96049 , Bamberg, Germany)

    2015-01-01

    Continuous monitoring of oceanic bottom water temperatures is a complicated task, even in relatively easy-to-access basins like the North or Baltic seas. Here, a method to determine annual bottom water temperature variations from inverse modeling of instantaneous measurements of temperatures and sediment thermal properties is presented. This concept is similar to climate reconstructions over several thousand years from deep borehole data. However, in contrast, the presented ...

  13. Sea Bottom Classification by Means of Bathymetric LIDAR Data

    OpenAIRE

    Velasco Gomez, Jesus; Molina Sánchez, Iñigo; Martínez Izquierdo, M.Estibaliz; Arquero Hidalgo, Águeda; Prieto Morin, Juan Francisco

    2014-01-01

    Light Detection and Ranging (LIDAR) provides high horizontal and vertical resolution of spatial data located in point cloud images, and is increasingly being used in a number of applications and disciplines, which have concentrated on the exploit and manipulation of the data using mainly its three dimensional nature. Bathymetric LIDAR systems and data are mainly focused to map depths in shallow and clear waters with a high degree of accuracy. Additionally, the backscattering produced by the ...

  14. Summer sea ice characteristics of the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.

  15. Aggregation and attachment responses of blue mussels, Mytilus edulis—impact of substrate composition, time scale and source of mussel seed

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Hansen, Benni Winding;

    2015-01-01

    Survival after transplantation of mussel seeds is crucial for the production output of blue mussels (Mytilus edulis L.) in bottom cultures. Hence, an understanding of the interactions between bed formation, habitat structure and performance of mussel seed of different origins can contribute...... a suspended long line culture. The mussels were applied to experimental units of complex and smooth substrate on the sea bed. Data on aggregation (day 0, day 1 and day 2), attachment strength (day 2 and 30), loss (day 2 and 30) and growth (day 0–30) of musselswere collected during the experiment. The results...

  16. Species diversity variations in Neogene deep-sea benthic foraminifera at ODP Hole 730A, western Arabian Sea

    Indian Academy of Sciences (India)

    Yuvaraja Arumugm; Anil K Gupta; Mruganka K Panigrahi

    2014-10-01

    Deep-sea benthic foraminifera are an important and widely used marine proxy to understand paleoceanographic and paleoclimatic changes on regional and global scales, owing to their sensitivity to oceanic and climatic turnovers. Some species of benthic foraminifera are sensitive to changes in water mass properties whereas others are sensitive to organic fluxes and deep-sea oxygenation. Benthic faunal diversity has been found closely linked to food web, bottom water oxygen levels, and substrate and water mass stability. The present study is aimed at analyzing species diversity trends in benthic foraminifera and their linkages with Indian monsoon variability during the Neogene. Species diversity of benthic foraminifera is examined in terms of number of species (S), information function (H), equitability (E) and Sanders’ rarefied values, which were combined with relative abundances of high and low productivity benthic foraminifera at Ocean Drilling Program Hole 730A, Oman margin, western Arabian Sea. The Oman margin offers the best opportunity to understand monsoon-driven changes in benthic diversity since summer monsoon winds have greater impact on the study area. The species diversity was higher during the early Miocene Climatic Optimum (∼17.2–16.4 Ma) followed by a decrease during 16.4–13 Ma coinciding with a major increase in Antarctic ice volume and increased formation of Antarctic Bottom Water. All the diversity parameters show an increase during 13–11.6 Ma, a gradual decrease during 11.6–9 Ma and then an increase with a maximum at 7 Ma. Thereafter the values show little change until 1.2 Ma when all the parameters abruptly decrease. The benthic foraminiferal populations and diversity at Hole 730A were mainly driven by the Indian monsoon, and polar waters might have played a minor or no role since early Neogene period as the Arabian Sea is an enclosed basin.

  17. Combining benthic foraminiferal ecology and shell Mn/Ca to deconvolve past bottom water oxygenation and paleoproductivity

    NARCIS (Netherlands)

    Koho, K.A.; de Nooijer, L.J.; Reichart, G.J.

    2015-01-01

    The Mn/Ca of carbonate tests of living deep-sea foraminifera (Hoeglundina elegans, Bulimina aculeata, Uvigerina peregrina and Melonis barleeanus) were determined together with pore water manganese along a bottom water oxygen gradient across the lower boundary of the Arabian Sea oxygen minimum zone.

  18. The bottom oxygen border of bioluminescence distribution in ocean

    Science.gov (United States)

    Zavoruev, Valerii

    2006-02-01

    From materials of forwarding researches follows, that the depth of deposition of the bottom border of bioluminescence plankton has not correlation with any of measurable hydrological parameters. As the reaction of bioluminescence is oxygen depended, it was logical to assume, that the situation of the bottom maximum of luminescence plankton is determined by concentration of oxygen. The data of vertical distribution of bioluminescence intensity of plankton and concentration of oxygen received in the Black Sea and near to east coast of America were investigated. Is established, that the deep maximum of bioluminescence of plankton is found out between isooxygen 0.35 and 0.20 ml/l. At concentration of oxygen in water is lower 0.10-0.20 ml/l the bioluminescence of plankton it is not found out.

  19. Variations in ectoenzymatic hydrolytic activity in an oligotrophic environment (Southern Tyrrhenian Sea, W Mediterranean)

    Science.gov (United States)

    Misic, Cristina; Castellano, Michela; Ruggieri, Nicoletta; Harriague, Anabella Covazzi

    2008-09-01

    The variations in the expression of two hydrolytic ectoenzymes (leucine aminopeptidase - LA - and β glucosidase — BG) were studied in the southern Tyrrhenian Sea during spring 2004. This area is characterised by a complex morphology and hydrodynamism, which generate significant differences between different sectors, particularly in the 0-100 m layer. However, the area generally exhibits oligotrophic features such as low autotrophic pigment and organic matter concentrations and a higher bacterial biomass than the phytoplanktonic one. Despite this general bottom-up pressure, adaptations by the microbial consumers were indicated by the ectoenzymatic activities and by the relationships between the enzymes, their organic substrates and their producers (namely the bacteria). In particular, bacteria were able to exploit the inorganic N supply (nitrite + nitrate provided by irregular intrusions of intermediate waters) to escape the bottom-up limitation and produce enzymes such as BG devoted to the degradation of cellulose remnants and, therefore, also able to take advantage on this refractory organic matter. In the 200-800 m layer, where trophic limitation was strong due to the low values of potentially-labile organic matter (namely proteins), the peculiar hydrodynamism led to the formation of nepheloid layers rich in organic matter, which provided the bacteria with substrates and allowed the development of a significant correlation between LA activity and its own organic substrate. Furthermore, a reduction of the bottom-up pressure was also indicated by a higher mean bacteria cell size in the entire water column of the central and eastern sectors, and a significantly increased expression of BG related to the increase in the cell size. The ectoenzymatic activities, therefore, suggested that the southern Tyrrhenian Sea should be considered as a mosaic of subsystems, where the peculiar hydrological features stimulate bacterial adaptations and enhance the channelling of

  20. Meiobenthos under mariculture conditions of the brown seaweed Saccharina japonica in Rifovaya Bay, Peter the Great Gulf, Sea of Japan

    Science.gov (United States)

    Belogurova, L. S.; Maslennikov, S. I.

    2016-07-01

    The qualitative and quantitative compositions of free-living marine nematodes were studied in Rifovaya Bay (Peter the Great Gulf, Sea of Japan). It was found that the density distribution of nematode populations in bottom sediments of Rifovaya Bay is nonuniform. In total, 72 nematode species were found, including Oncholaimium paraolium, Viscosia epapilosa, and Monoposthia latiannulata on all types of substrates. The dominant trophic group comprised "predators" (2B) and "scrapers" (2A). It was shown that the species composition of nematodes in Rifovaya Bay is very similar to the species composition of nematodes in the other areas of Peter the Great Gulf.

  1. Impact of bottom trawling on sediment characteristics - A study along inshore waters off Veraval coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Bhagirathan, U.; Meenakumari, B.; Jayalakshmy, K.V.; Panda, S.K.; Madhu, V.R.; Vaghela, D.T.

    marine sediments has been documented by Schwinghamer et al. (1998) along Grand Banks of Newfoundland, Duplisea et al. (2001) in the North Sea and Pusceddu et al. (2005) in the Gulf of Thermaikos (Aegean Sea). A number of studies have been conducted... al. (1998) at the sandy bottom of the Grand Banks of Newfoundland showed that trawling changed the individual sediment grains to smooth, clean and light in colour. This change was at- tributed to the reduction in surficial biogenic sed- iment...

  2. A method for treating bottom ash

    NARCIS (Netherlands)

    Rem, P.C.; Van Craaikamp, H.; Berkhout, S.P.M.; Sierhuis, W.; Van Kooy, L.A.

    2007-01-01

    A method for treating bottom ash from a waste incineration plant. The invention relates in particular to a method for treating bottom ash from a domestic waste incineration plant. In accordance with the invention bottom ash having a size ranging up to 2 mm is treated by removing a previously determi

  3. Bottom temperature and salinity distribution and its variability around Iceland

    Science.gov (United States)

    Jochumsen, Kerstin; Schnurr, Sarah M.; Quadfasel, Detlef

    2016-05-01

    The barrier formed by the Greenland-Scotland-Ridge (GSR) shapes the oceanic conditions in the region around Iceland. Deep water cannot be exchanged across the ridge, and only limited water mass exchange in intermediate layers is possible through deep channels, where the flow is directed southwestward (the Nordic Overflows). As a result, the near-bottom water masses in the deep basins of the northern North Atlantic and the Nordic Seas hold major temperature differences. Here, we use near-bottom measurements of about 88,000 CTD (conductivity-temperature-depth) and bottle profiles, collected in the period 1900-2008, to investigate the distribution of near-bottom properties. Data are gridded into regular boxes of about 11 km size and interpolated following isobaths. We derive average spatial temperature and salinity distributions in the region around Iceland, showing the influence of the GSR on the near-bottom hydrography. The spatial distribution of standard deviation is used to identify local variability, which is enhanced near water mass fronts. Finally, property changes within the period 1975-2008 are presented using time series analysis techniques for a collection of grid boxes with sufficient data resolution. Seasonal variability, as well as long term trends are discussed for different bottom depth classes, representing varying water masses. The seasonal cycle is most pronounced in temperature and decreases with depth (mean amplitudes of 2.2 °C in the near surface layers vs. 0.2 °C at depths > 500 m), while linear trends are evident in both temperature and salinity (maxima in shallow waters of +0.33 °C/decade for temperature and +0.03/decade for salinity).

  4. A freshwater species wintering in a brackish environment: Habitat selection and diet of Slavonian grebes in the southern Baltic Sea

    Science.gov (United States)

    Sonntag, Nicole; Garthe, Stefan; Adler, Sven

    2009-09-01

    After the breeding season, Slavonian grebes ( Podiceps auritus) leave their freshwater breeding habitats and migrate to wintering grounds in marine or brackish waters. The most important wintering area in northwestern Europe is located in the southern Baltic Sea, with the largest concentrations in the offshore area of the Pommeranian Bight. Analysis of ship-based surveys revealed that the habitat selection of Slavonian grebes in this brackish area is significantly influenced by water depth and bottom sediment type. The grebes prefer shallow waters of 4-14 m depth and occur only over sandy sediments. While the diving depths of endothermic animals is limited due to energetic constraints and thermoregulation, sediment type is regarded to be a proxy for food choice. The diet of Slavonian grebes in the Pomeranian Bight consists mainly of demersal gobies (Gobiidae) that frequently occur over sandy bottom substrates.

  5. Bottom-up fabrication of graphene nanostructures on Ru(1010).

    Science.gov (United States)

    Song, Junjie; Zhang, Han-jie; Cai, Yiliang; Zhang, Yuxi; Bao, Shining; He, Pimo

    2016-02-01

    Investigations on the bottom-up fabrication of graphene nanostructures with 10, 10'-dibromo-9, 9'-bianthryl (DBBA) as a precursor on Ru(1010) were carried out using scanning tunnelling microscopy (STM) and density functional theory (DFT) calculations. Upon annealing the sample at submonolayer DBBA coverage, N = 7 graphene nanoribbons (GNRs) aligned along the [1210] direction form. Higher DBBA coverage and higher annealing temperature lead to the merging of GNRs into ribbon-like graphene nanoflakes with multiple orientations. These nanoflakes show different Moiré patterns, and their structures were determined by DFT simulations. The results showed that GNRs possess growth preference on the Ru(1010) substrate with a rectangular unit cell, and GNRs with armchair and zigzag boundaries are obtainable. Further DFT calculations suggest that the interaction between graphene and the substrate controls the orientations of the graphene overlayer and the growth of graphene on Ru(1010).

  6. Perceptual learning: top to bottom.

    Science.gov (United States)

    Amitay, Sygal; Zhang, Yu-Xuan; Jones, Pete R; Moore, David R

    2014-06-01

    Perceptual learning has traditionally been portrayed as a bottom-up phenomenon that improves encoding or decoding of the trained stimulus. Cognitive skills such as attention and memory are thought to drive, guide and modulate learning but are, with notable exceptions, not generally considered to undergo changes themselves as a result of training with simple perceptual tasks. Moreover, shifts in threshold are interpreted as shifts in perceptual sensitivity, with no consideration for non-sensory factors (such as response bias) that may contribute to these changes. Accumulating evidence from our own research and others shows that perceptual learning is a conglomeration of effects, with training-induced changes ranging from the lowest (noise reduction in the phase locking of auditory signals) to the highest (working memory capacity) level of processing, and includes contributions from non-sensory factors that affect decision making even on a "simple" auditory task such as frequency discrimination. We discuss our emerging view of learning as a process that increases the signal-to-noise ratio associated with perceptual tasks by tackling noise sources and inefficiencies that cause performance bottlenecks, and present some implications for training populations other than young, smart, attentive and highly-motivated college students.

  7. Microbial abundance in the coelenteron and mucus of the cold-water Coral Lophelia pertusa and in bottom water of the reef environment

    OpenAIRE

    Weinbauer, M.G.; Ogier, J.; Maier, C.

    2012-01-01

    Microorganisms play an important role in coral ecology; however, little is known about cold-water coral (CWC) reefs. Microbial abundance in bottom water of Lophelia pertusa-dominated CWC reefs in the Skagerrak, North Sea, was elevated by ca. 40% for prokaryotes and 70 to 90% for viruses compared to bottom water where no corals were present. This indicates that CWCs influence the microbial food web in bottom water. Furthermore, results suggest that microorganisms contributed significantly to t...

  8. Sea-ice algal primary production and nitrogen uptake rates off East Antarctica

    Science.gov (United States)

    Roukaerts, Arnout; Cavagna, Anne-Julie; Fripiat, François; Lannuzel, Delphine; Meiners, Klaus M.; Dehairs, Frank

    2016-09-01

    Antarctic pack ice comprises about 90% of the sea ice in the southern hemisphere and plays an important structuring role in Antarctic marine ecosystems, yet measurements of ice algal primary production and nitrogen uptake rates remain scarce. During the early austral spring of 2012, measurements for primary production rates and uptake of two nitrogen substrates (nitrate and ammonium) were conducted at 5 stations in the East Antarctic pack ice (63-66°S, 115-125°E). Carbon uptake was low (3.52 mg C m-2 d-1) but a trend of increased production was observed towards the end of the voyage suggesting pre-bloom conditions. Significant snow covers reaching, up to 0.8 m, induced strong light limitation. Two different regimes were observed in the ice with primarily nitrate based 'new' production (f-ratio: 0.80-0.95) at the bottom of the ice cover, due to nutrient-replete conditions at the ice-water interface, and common for pre-bloom conditions. In the sea-ice interior, POC:PN ratios (20-70) and higher POC:Chl a ratios suggested the presence of large amounts of detrital material trapped in the ice and here ammonium was the prevailing nitrogen substrate. This suggests that most primary production in the sea-ice interior was regenerated and supported by a microbial food web, recycling detritus.

  9. Wet physical separation of MSWI bottom ash

    NARCIS (Netherlands)

    Muchova, L.

    2010-01-01

    Bottom ash (BA) from municipal solid waste incineration (MSWI) has high potential for the recovery of valuable secondary materials. For example, the MSWI bottom ash produced by the incinerator at Amsterdam contains materials such as non-ferrous metals (2.3%), ferrous metals (8-13%), gold (0.4 ppm),

  10. Development of Castables for Gass Tank Bottom

    Institute of Scientific and Technical Information of China (English)

    YUANLin; CHENShengling

    1998-01-01

    The production and use of zircon corundum refractory castables were analyzed.The superior properties and applied effect of castables for glass tank bottom were demonstrated.The results show that those castables have excellent molten glass corrosion resistance (MGCR) and enable glass tank bot-tom to form a seal mass.

  11. Ocean Bottom Seismometers technology: current state and future outlook

    Science.gov (United States)

    Ilinskiy, Dmitry; Ganzha, Oleg

    2016-04-01

    The beginning of 2000s was marked by a significant progress in the development and use of self-pop-up sea-bottom seismic recorders (Ocean Bottom Seismometers). In Russia it was a novel solution developed by the Russian Academy of Sciences Experimental Design Bureau of Oceanological Engineering. This recorder and its clones have been widely used not only for the Earth crust studies, but also for investigations of sub-basalt structures and gas hydrate exploration. And what has happened over the last 10 years? Let us look closely at the second generation of ocean bottom stations developed by Geonodal Solutions (GNS) as an illustration of the next step forward in the sea-bottom acquisition technology. First of all, hardware components have changed dramatically. The electronic components became much smaller, accordingly, the power consumption and electronic self-noise were dropped down significantly. This enabled development of compact station 330 mm in diameter instead of previous 450mm. The weight fell by half, while the autonomy increased up to 90 days due to both decreased energy consumption and increased capacity of the batteries. The dynamic range of recorded seismic data has expended as a result of decreased set noise and the application of 24-bit A/D converters. The instruments dimensions have been reduced, power consumption decreased, clock accuracy was significantly improved. At the same time, development of advanced time reference algorithms enabled to retain instrument accuracy around 1 ms during all the autonomous recording period. The high-speed wireless data transfer technology offered a chance to develop "maintenance-free" station throughout its operation time. The station can be re-used at the different sea bottom locations without unsealing of the deep-water container for data download, battery re-charge, clock synchronization. This noticeably reduces the labor efforts of the personnel working with the stations. This is critically important in field

  12. The oscillations of ship lock bottom

    Directory of Open Access Journals (Sweden)

    N.Yu. Kuzmin

    2012-06-01

    Full Text Available The article deals with the dynamic characteristics of the ship lock. The accurate design relations intended to study the natural and forced vibrations of the bottom of the ship lock are provided. The degree of filling of the lock, as well as the added mass of water is considered. The various coupling conditions of the bottom and walls of buildings are taken into account. A concrete example of the calculation is given.An exact, in the framework of the adopted design scheme, solution of the problem of the own and forced vibrations of the bottom of the ship lock is found. The frequency of the first five tones of vibrations and the associated mass of liquid according to thickness of the structure and coupling conditions of the bottom and sides of the lock are analyzed. A significant effect of liquids on low-frequency part of the spectrum and the dynamic response of the bottom is determined.

  13. Processing of airborne lidar bathymetry data for detailed sea floor mapping

    Science.gov (United States)

    Tulldahl, H. Michael

    2014-10-01

    Airborne bathymetric lidar has proven to be a valuable sensor for rapid and accurate sounding of shallow water areas. With advanced processing of the lidar data, detailed mapping of the sea floor with various objects and vegetation is possible. This mapping capability has a wide range of applications including detection of mine-like objects, mapping marine natural resources, and fish spawning areas, as well as supporting the fulfillment of national and international environmental monitoring directives. Although data sets collected by subsea systems give a high degree of credibility they can benefit from a combination with lidar for surveying and monitoring larger areas. With lidar-based sea floor maps containing information of substrate and attached vegetation, the field investigations become more efficient. Field data collection can be directed into selected areas and even focused to identification of specific targets detected in the lidar map. The purpose of this work is to describe the performance for detection and classification of sea floor objects and vegetation, for the lidar seeing through the water column. With both experimental and simulated data we examine the lidar signal characteristics depending on bottom depth, substrate type, and vegetation. The experimental evaluation is based on lidar data from field documented sites, where field data were taken from underwater video recordings. To be able to accurately extract the information from the received lidar signal, it is necessary to account for the air-water interface and the water medium. The information content is hidden in the lidar depth data, also referred to as point data, and also in the shape of the received lidar waveform. The returned lidar signal is affected by environmental factors such as bottom depth and water turbidity, as well as lidar system factors such as laser beam footprint size and sounding density.

  14. Eco-friendly porous concrete using bottom ash aggregate for marine ranch application.

    Science.gov (United States)

    Lee, Byung Jae; Prabhu, G Ganesh; Lee, Bong Chun; Kim, Yun Yong

    2016-03-01

    This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application. PMID:26687102

  15. Eco-friendly porous concrete using bottom ash aggregate for marine ranch application.

    Science.gov (United States)

    Lee, Byung Jae; Prabhu, G Ganesh; Lee, Bong Chun; Kim, Yun Yong

    2016-03-01

    This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application.

  16. CHARACTERISTICS OF SLUDGE BOTTOM MESH

    Directory of Open Access Journals (Sweden)

    Kamil Szydłowski

    2016-05-01

    Full Text Available The main aim of the study was to assess the selected heavy metals pollution of bottom sediments of small water bodies of different catchment management. Two ponds located in Mostkowo village were chosen for investigation. The first small water reservoir is surrounded by the cereal fields, cultivated without the use of organic and mineral fertilizers (NPK. The second reservoir is located in a park near rural buildings. Sediment samples were collected by the usage of KC Denmark sediments core probe. Samples were taken from 4 layers of sediment, from depth: 0–5, 5–10, 10–20 and 20–30 cm. Sampling was made once during the winter period (2014 year when ice occurred on the surface of small water bodies, from three points. The material was prepared for further analysis according to procedures used in soil science. The content of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn were determined by atomic absorption spectrometry by usage of ASA ICE 3000 Thermo Scientific after prior digestion in the mixture (5: 1 of concentrated acids (HNO3 and HClO4. Higher pH values ​​were characteristic for sediments of pond located in a park than in pond located within the agricultural fields. In both small water bodies the highest heavy metal concentrations occurred in the deepest points of the research. In the sediments of the pond located within crop fields the highest concentration of cadmium, copper, lead and zinc were observed in a layer of 0–5 cm, wherein the nickel and chromium in a layer of 20–30 cm. In the sediments of the pond, located in the park the highest values ​​occurred at the deepest sampling point in the layer taken form 10–20 cm. Sediments from second reservoir were characterized by the largest average concentrations of heavy metals, except the lead content in sediment form the layer of 10–20 cm. According to the geochemical evaluation of sediments proposed by Bojakowska and Sokołowska [1998], the majority of samples belongs to Ist

  17. Bio-engineering in the Baltic Sea

    DEFF Research Database (Denmark)

    Zandersen, Marianne

    2011-01-01

    Bio-engineering in the Baltic Sea – value of water quality improvements & risk perceptions Dr. Marianne Zandersen1 Department of Environmental Science, Aarhus University Abstract The Baltic Sea is heavily eutrofied and the trend has gone from bad to worse. The hypoxic zone has increased about 4...... of the water column to the bottom waters/deepwater. The expected effects include a slowing down of the sediment release from the bottom and improvement of the possibilities for aerobic bacterial decomposition and over time for the establishment of fauna. The projects test a bio-engineered approach to speeding...

  18. Pipeline bottoming cycle study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The technical and economic feasibility of applying bottoming cycles to the prime movers that drive the compressors of natural gas pipelines was studied. These bottoming cycles convert some of the waste heat from the exhaust gas of the prime movers into shaft power and conserve gas. Three typical compressor station sites were selected, each on a different pipeline. Although the prime movers were different, they were similar enough in exhaust gas flow rate and temperature that a single bottoming cycle system could be designed, with some modifications, for all three sites. Preliminary design included selection of the bottoming cycle working fluid, optimization of the cycle, and design of the components, such as turbine, vapor generator and condensers. Installation drawings were made and hardware and installation costs were estimated. The results of the economic assessment of retrofitting bottoming cycle systems on the three selected sites indicated that profitability was strongly dependent upon the site-specific installation costs, how the energy was used and the yearly utilization of the apparatus. The study indicated that the bottoming cycles are a competitive investment alternative for certain applications for the pipeline industry. Bottoming cycles are technically feasible. It was concluded that proper design and operating practices would reduce the environmental and safety hazards to acceptable levels. The amount of gas that could be saved through the year 2000 by the adoption of bottoming cycles for two different supply projections was estimated as from 0.296 trillion ft/sup 3/ for a low supply projection to 0.734 trillion ft/sup 3/ for a high supply projection. The potential market for bottoming cycle equipment for the two supply projections varied from 170 to 500 units of varying size. Finally, a demonstration program plan was developed.

  19. Bottom-strange mesons in hyperonic matter

    OpenAIRE

    Pathak, Divakar; Mishra, Amruta

    2014-01-01

    The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of t...

  20. Power electronics substrate for direct substrate cooling

    Science.gov (United States)

    Le, Khiet; Ward, Terence G.; Mann, Brooks S.; Yankoski, Edward P.; Smith, Gregory S.

    2012-05-01

    Systems and apparatus are provided for power electronics substrates adapted for direct substrate cooling. A power electronics substrate comprises a first surface configured to have electrical circuitry disposed thereon, a second surface, and a plurality of physical features on the second surface. The physical features are configured to promote a turbulent boundary layer in a coolant impinged upon the second surface.

  1. Ploughing the deep sea floor

    OpenAIRE

    Puig, Pere; Canals, Miquel; Company, Joan B.; Martín, Jacobo; Amblas, David; Lastras, Galderic; Palanques, Albert; Calafat, Antoni M.

    2012-01-01

    Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations1, 2 and benthic communities3, 4 has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes5, 6. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and ...

  2. Landfilling: Bottom Lining and Leachate Collection

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Manfredi, Simone; Kjeldsen, Peter;

    2011-01-01

    The critical element of a landfill, which is essential for the protection of the environment in general, and prevention of contamination of the underlying soils and groundwater in particular, is the bottom lining system. The major focus of the bottom lining system development is to prevent leachate...... from entering the groundwater or surface water. The bottom lining system should cover the full footprint area of the landfill, including both the relatively flat bottom and the sideslopes in the case of an excavated configuration. This prevents the lateral migration of leachate from within the landfill...... works together with the overlying leachate management system, also referred to as the leachate collection and removal system (LCRS), which consists of a drainage layer that provides easy horizontal drainage of the leachate to a point of gravitational collection or pumping. Although individual liners...

  3. Measurement of marine radionuclide distribution using a towed sea-bed spectrometer

    International Nuclear Information System (INIS)

    The application of in situ gamma-ray spectrometry to the measurement of radionuclide concentration in sea water and sea-bed sediment is discussed with special reference to a towed sea-bed gamma-ray spectrometer survey of radio-effluent distribution in the Irish Sea. Contour maps produced from the spectrometer profiles are matched with the distribution of bottom sediment types and conclusions are drawn concerning the modes of transport and deposition of 137Cs in the Irish Sea. (author)

  4. Comprehensive studies in the Black Sea and the Sea of Azov in the Summer of 2012

    Science.gov (United States)

    Matishov, G. G.; Nabozhenko, M. V.; Shokhin, I. V.; Zolotareva, A. E.; Bulysheva, N. I.; Semin, V. L.; Polshin, V. V.; Povazhnyi, V. V.; Verbitskyi, R. E.; Verbitskyi, E. V.; Sapozhnikov, F. V.; Spiridonov, V. A.; Zalota, A. K.

    2013-05-01

    The shelf zones of the Black Sea, Taman Bay, and the Sea of Azov are currently subjected to gross load related to the impact of invasive species, large-scale construction activities near the coast, intensive recreation activity, water pollution in large cities and ports, active navigation, unreasonable coastal arrangement, and dam construction. Another factor substantially affecting the composition of bottom sediments and, thus, the benthos environment is the terrigenous material carried by rivers in the course of catastrophic overflows. An example is the Kubansk flood in 2012, which significantly affected the sea coast near Novorossiysk, Gelendzhik, and Divnomorsk. The intensive onshore dumping results in the delivery of abundant allochthonous material, bottom silting causing changes in the dominants in the benthos associations, a decrease in the photic layer and the death of the phytobenthos, and also debris formation at the bottom. Debris can play the role of artificial reefs contributory for the formation of periphytic biocoenoses.

  5. Random Seas

    DEFF Research Database (Denmark)

    Liu, Z.; Frigaard, Peter

    Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures.......Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures....

  6. The Suspended Sediment Concentration Distribution in the Bohai Sea, Yellow Sea and East China Sea

    Institute of Scientific and Technical Information of China (English)

    BIAN Changwei; JIANG Wensheng; Richard J.Greatbatch; DING Hui

    2013-01-01

    The distribution of the suspended sediment eoncentration (SSC) in the Bohai Sea,Yellow Sea and East China Sea (BYECS) is studied based on the observed turbidity data and model simulation results.The observed turbidity results show that (i)the highest SSC is found in the coastal areas while in the outer shelf sea areas turbid water is much more difficult to observe,(ii) the surface layer SSC is much lower than the bottom layer SSC and (iii) the winter SSC is higher than the summer SSC.The Regional Ocean Modeling System (ROMS) is used to simulate the SSC distribution in the BYECS.A comparison between the modeled SSC and the observed SSC in the BYECS shows that the modeled SSC can reproduce the principal features of the SSC distribution in the BYECS.The dynamic mechanisms of the sediment erosion and transport processes are studied based on the modeled results.The horizontal distribution of the SSC in the BYECS is mainly determined by the current-wave induced bottom stress and the fine-grain sediment distribution.The current-induced bottom stress is much higher than the wave-induced bottom stress,which means the tidal currents play a more significant role in the sediment resuspension than the wind waves.The vertical mixing strength is studied based on the mixed layer depth and the turbulent kinetic energy distribution in the BYECS.The strong winter time vertical mixing,which is mainly caused by the strong wind stress and surface cooling,leads to high surface layer SSC in winter.High surface layer SSC in summer is restricted in the coastal areas.

  7. A Study on the Environmental Standard of Sediment on the Bottom of the Water

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Yoo, Hye Jin [Korea Environment Institute, Seoul (Korea)

    2000-12-01

    Sediment on the bottom of the water has been considered one of the water pollutants in the environmental management of Korea so treated as a management on pollutants, as you can see the examples in the dragging operation in the polluted sea area. To healthily maintain and conserve the water ecosystem including bottom living things in the water, sediment on the bottom of the water should be recognized as the independent medium, which should maintain the certain quality like the water, the atmosphere, and soil, rather than the source of water pollution. Such recognition means that the management of sediment on the bottom of the water should change the fragmentary goal, centered the post management focusing on the water management, to the ecosystematic goal including the bottom living things. In a point of the view, this study has a great significance to suggest not only the final goal for the management of sediment on the bottom of the water but also the necessity of developing the environmental standard of the sediment on the bottom of the water, which is a standard of the management or judgment in the actual managing the sediment on the bottom of the water - an estimation on the pollution of sediment, a removal of the polluted sediment, a purification of sediment, and an abandonment of the dragged sediment -, and the development measures. Considering the situation that even the basic scheme related to the management of sediment is not prepared in the Government level, the concept of the environmental standard of sediment, the foreign example of the environmental standard of sediment, the current state of the domestic sediment pollution, and the development scheme of the environmental standard in this study must be the important foundation to establish the management system of sediment in the Government level. 121 refs., 10 figs., 45 tabs.

  8. Method for vessel attitude estimation by spatial correlation function for bottom reverberation

    Institute of Scientific and Technical Information of China (English)

    FENG Lei; DENG Kai; WANG Changhong

    2006-01-01

    Under the assumption that the sea bottom is an almost-flat and randomly rough thin layer, a spatial correlation model for bottom reverberation is constructed. At high signal noise ratio, the phase of the spatial correlation function is the product of sound wave number and the vertical vector between two hydrophones. In a nominally horizontal plane, roll and pitch bring on the vertical vector between the hydrophones. Then an equation including roll, pitch and the phase of the spatial correlation function is found. If a parallelogram can be constructed by 3 hydrophones and the ratios of its acreage to diagonals are not smaller than half of the wavelength, roll and pitch can be obtained analytically or by optimal method. However, the ranges of roll and pitch are restricted because of the phase ambiguity. Using Fisher information matrix, the Cramer-Rao lower bound is obtained. Results from computer simulation and sea test data prove the feasibility of the method.

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

    Science.gov (United States)

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

    2006-10-01

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

  10. Sub-bottom profiling for large-scale maritime archaeological survey An experience-based approach

    DEFF Research Database (Denmark)

    Grøn, Ole; Boldreel, Lars Ole

    2013-01-01

    The development of cost-effective management strategies, including mapping of the submerged cultural heritage - potentially extensive even at quite great depths - is becoming ever more important, given increasing commercial activity in marine areas which may cause damage or prevent further...... and wrecks partially or wholly embedded in the sea-floor sediments demands the application of highresolution sub-bottom profilers. This paper presents a strategy for the cost-effective large-scale mapping of unknown sedimentembedded sites such as submerged Stone Age settlements or wrecks, based on sub......-bottom profiling with chirp systems. The mapping strategy described includes: a) definition of line spacing depending on the target; b) interactive sailing, i.e. when potential archaeological anomalies are located, their character is immediately investigated in more detail by a denser pattern of sub-bottom survey...

  11. Benthic Macrofauna Associated with Submerged Bottoms of a Tectonic Estuary in Tropical Eastern Pacific

    Directory of Open Access Journals (Sweden)

    Carlos E. Guevara-Fletcher

    2011-01-01

    Full Text Available The composition and distribution of the main associations of submerged macrobenthos of Bahía Málaga (Colombian pacific coast, were studied in relation to the distribution of hard and soft substrates and some abiotic factors. Eight localities were sampled during six months: three in the external border of the estuary and five in the inner part. In total, 728 organisms were registered, belonging to 207 species, 132 genera, 86 families, and 14 orders of six invertebrate groups (Porifera, Cnidaria, Polychaeta, Mollusca, Crustacea, and Echinodermata. The submerged bottoms presented soft and hard substrates, with rocks and thick sand in five sites, soft bottoms with fine sand in one, and soft bottoms with slime and clay in two. The temperature and salinity values were higher in the external localities, while dissolved oxygen and pH were higher in the internal localities. The localities with hard substrates presented the highest richness of species while the soft substrates, were characterized by a paucity of species and individuals. The similarity classification analyses showed two groups: one characterized by having 61 species in common and high richness with 113 exclusive species. The other group with low diversity and richness values, 37 species in common and 23 exclusive species.

  12. Dead sea asphalts: historical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A.

    1978-05-01

    Asphalts are present in the Dead Sea basin in three forms: (1) huge blocks, up to 100 tons in weight, composed of extremely pure (>99.99%) solid asphalt occasionally found floating on the lake, (2) veins, seepages, and cavity and fissure fillings in Lower Cretaceous to Holocene rocks, and (3) ozocerite veins on the eastern shore of the lake. Dead Sea asphalts probably have been documented over a longer period of time than any other hydrocarbon deposit--from antiquity to the 19th century. Major uses of asphalt from the Dead Sea have been as an ingredient in the embalming process, for medicinal purposes, for fumigation, and for agriculture. The first known war for control of a hydrocarbon deposit was in the Dead Sea area in 312 B.C. between the Seleucid Syrians and the Nabatean Arabs who lived around the lake. Surface manifestations of asphalt are linked closely to tectonic activity. In the lake itself, the asphalt is associated with diapirs During certain historic periods, tectonic and diapiric activity caused frequent liberation to the Dead Sea surface of semiliquid asphalt associated with large amounts of hydrogen sulfide gas. When the tectonic activity was attenuated, as in the 19th and 20th centuries, the rate of asphalt seepage to the bottom sediments of the Dead Sea was much slower and the asphalt solidified on the lake bottom. The release of asphalt to the surface became much more sporadic, and may have resulted in part from earthquakes. Thus, future asphalt prospecting in the Dead Sea area should be conducted along the boundaries of diapirs or their associated faults.

  13. 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

    Bottom-mounted acoustic Doppler current profiler measurements indicate that the net transport of water (844 m3 s-1) in the Little Belt makes up only 6% of the total transport between the Baltic Sea and the North Sea. This is a smaller percentage than the 9% commonly found in the literature. Owing...

  14. Solar radiation interactions with seasonal sea ice

    Science.gov (United States)

    Ehn, Jens Kristian

    Presently, the Arctic Ocean is undergoing an escalating reduction in sea ice and a transition towards a seasonal sea ice environment. This warrants detailed investigations into improving our understanding of the seasonal evolution of sea ice and snow covers, and their representation in climate models. The interaction of solar radiation with sea ice is an important process influencing the energy balance and biological activity in polar seas, and consequently plays a key role in the earth's climate system. This thesis focuses on characterization of the optical properties---and the underlying physical properties that determine them---of seasonal sea ice during the fall freeze-up and the spring melt periods. Both periods display high spatial heterogeneity and rapid temporal changes in sea ice properties, and are therefore poorly understood. Field data were collected in Amundsen Gulf/Franklin Bay (FB), southern-eastern Beaufort Sea, in Oct.-Nov. 2003 and Apr. 2004 and in Button Bay (BB), western Hudson Bay, in Mar.-May 2005 to address (1) the temporal and spatial evolution of surface albedo and transmittance, (2) how radiative transfer in sea ice is controlled by its physical nature, and (3) the characteristics of the bottom ice algae community and its effect on the optical properties. The fall study showed the importance of surface features such as dry or slushy bare ice, frost flowers and snow cover in determining the surface albedo. Ice thickness was also important, however, mostly because surface features were associated with thickness. For example, nilas (snow layer as snow grains were dissolved or merged with the salty and warm brine skim layer on the surface, while surface conditions on thicker ice types were cold and dry enough to support a snow cover. In general, the surface albedo increased exponentially with an ice thickness increase, however, variability within ice thickness types were very large. It is apparent that a more complete treatment of brine

  15. Bottom Reflectance in Ocean Color Satellite Remote Sensing for Coral Reef Environments

    OpenAIRE

    Martina Reichstetter; Peter R. C. S. Fearns; Scarla J Weeks; McKinna, Lachlan I. W.; Chris Roelfsema; Miles Furnas

    2015-01-01

    Most ocean color algorithms are designed for optically deep waters, where the seafloor has little or no effect on remote sensing reflectance. This can lead to inaccurate retrievals of inherent optical properties (IOPs) in optically shallow water environments. Here, we investigate in situ hyperspectral bottom reflectance signatures and their separability for coral reef waters, when observed at the spectral resolutions of MODIS and SeaWiFS sensors. We use radiative transfer modeling to calculat...

  16. A novel esterase gene cloned from a metagenomic library from neritic sediments of the South China Sea

    Directory of Open Access Journals (Sweden)

    Peng Qing

    2011-11-01

    Full Text Available Abstract Background Marine microbes are a large and diverse group, which are exposed to a wide variety of pressure, temperature, salinity, nutrient availability and other environmental conditions. They provide a huge potential source of novel enzymes with unique properties that may be useful in industry and biotechnology. To explore the lipolytic genetic resources in the South China Sea, 23 sediment samples were collected in the depth Results A metagenomic library of South China Sea sediments assemblage in plasmid vector containing about 194 Mb of community DNA was prepared. Screening of a part of the unamplified library resulted in isolation of 15 unique lipolytic clones with the ability to hydrolyze tributyrin. A positive recombinant clone (pNLE1, containing a novel esterase (Est_p1, was successfully expressed in E. coli and purified. In a series of assays, Est_p1 displayed maximal activity at pH 8.57, 40°C, with ρ-Nitrophenyl butyrate (C4 as substrate. Compared to other metagenomic esterases, Est_p1 played a notable role in specificity for substrate C4 (kcat/Km value 11,500 S-1m M-1 and showed no inhibited by phenylmethylsulfonyl fluoride, suggested that the substrate binding pocket was suitable for substrate C4 and the serine active-site residue was buried at the bottom of substrate binding pocket which sheltered by a lid structure. Conclusions Esterase, which specificity towards short chain fatty acids, especially butanoic acid, is commercially available as potent flavoring tools. According the outstanding activity and specificity for substrate C4, Est_p1 has potential application in flavor industries requiring hydrolysis of short chain esters.

  17. 46 CFR 154.305 - Segregation of hold spaces from the sea.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Segregation of hold spaces from the sea. 154.305 Section... Equipment Ship Arrangements § 154.305 Segregation of hold spaces from the sea. In vessels having cargo... sea by: (a) A double bottom if the cargo tanks meet this part for design temperatures colder than...

  18. Geodetic measurements at sea floor spreading centers

    Science.gov (United States)

    Spiess, F. N.

    1978-01-01

    A network of 8 or more precision transponder units mounted on the sea floor and interrogated periodically from an instrument package towed near bottom through the area to provide the necessary spatial averaging could provide a practical system for observing the pattern of buildup of strain at intermediate and fast spreading centers.

  19. Sea ice algal biomass and physiology in the Amundsen Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    Kevin R. Arrigo

    2014-07-01

    Full Text Available Abstract Sea ice covers approximately 5% of the ocean surface and is one of the most extensive ecosystems on the planet. The microbial communities that live in sea ice represent an important food source for numerous organisms at a time of year when phytoplankton in the water column are scarce. Here we describe the distributions and physiology of sea ice microalgae in the poorly studied Amundsen Sea sector of the Southern Ocean. Microalgal biomass was relatively high in sea ice in the Amundsen Sea, due primarily to well developed surface communities that would have been replenished with nutrients during seawater flooding of the surface as a result of heavy snow accumulation. Elevated biomass was also occasionally observed in slush, interior, and bottom ice microhabitats throughout the region. Sea ice microalgal photophysiology appeared to be controlled by the availability of both light and nutrients. Surface communities used an active xanthophyll cycle and effective pigment sunscreens to protect themselves from harmful ultraviolet and visible radiation. Acclimation to low light microhabitats in sea ice was facilitated by enhanced pigment content per cell, greater photosynthetic accessory pigments, and increased photosynthetic efficiency. Photoacclimation was especially effective in the bottom ice community, where ready access to nutrients would have allowed ice microalgae to synthesize a more efficient photosynthetic apparatus. Surprisingly, the pigment-detected prymnesiophyte Phaeocystis antarctica was an important component of surface communities (slush and surface ponds where its acclimation to high light may precondition it to seed phytoplankton blooms after the sea ice melts in spring.

  20. Characteristics of low-frequency components of the near-bottom current in the Chinese Pioneer Area

    Institute of Scientific and Technical Information of China (English)

    LIANG Chujin; HOU Yijun; CHEN Qi; DONG Ruzhou; DONG Lixian

    2004-01-01

    Two deep-sea moorings were deployed respectively in the east area and the west area of Chinese Pioneer Area (CPA) in the tropic east Pacific to monitor the regional deep-sea dynamics below 600 meters above bottom (mab) from July 1997 to Oct. 1999. Results of statistics, spectral estimate and correlation analysis of the low-passed velocity data show that time scales of low-frequency components of the near-bottom currents are 25~120 days, in which 51-day period dominates the lower band of the frequency domain. Topographic features have obvious effect on low-frequency currents below 50 mab; modulations of the bottom-intensified sheared mean flow to the low-frequency currents are the dynamic mechanism of the frequency shift that occurs in both the east-area and the west-area.

  1. ATOMIZATION CAUSED BY BOTTOM FLOW ENERGY DISSIPATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Bottom flow energy dissipation is one of the common energydissipation methods for flood-releasing structures with high water head. Measures of this energy dissipation depend mainly on the turbulent action of hydraulic jump.In this paper, the physical process and the calculating methods of the atomization caused by bottom flow energy dissipation were studied, the computation models of atomization quantity for the self-aerated flow in overflow and hydraulic jump regions are presented, and the main results are of theoretical and practical significance for the hydraulic and electric engineering.

  2. Palladium clusters deposited on the heterogeneous substrates

    Science.gov (United States)

    Wang, Kun; Liu, Juanfang; Chen, Qinghua

    2016-07-01

    To improve the performance of the Pd composite membrane prepared by the cold spraying technology, it is extremely essential to give insights into the deposition process of the cluster and the heterogeneous deposition of the big Pd cluster at the different incident velocities on the atomic level. The deposition behavior, morphologies, energetic and interfacial configuration were examined by the molecular dynamic simulation and characterized by the cluster flattening ratio, the substrate maximum local temperature, the atom-embedded layer number and the surface-alloy formation. According to the morphology evolution, three deposition stages and the corresponding structural and energy evolution were clearly identified. The cluster deformation and penetrating depth increased with the enhancement of the incident velocity, but the increase degree also depended on the substrate hardness. The interfacial interaction between the cluster and the substrate can be improved by the higher substrate local temperature. Furthermore, it is found that the surface alloys were formed by exchanging sites between the cluster and substrate atoms, and the cluster atoms rearranged following as the substrate lattice arrangement from bottom to up in the deposition course. The ability and scope of the structural reconstruction are largely determined by both the size and incident energy of the impacted cluster.

  3. Bottom-Up Cost Analysis of a High Concentration PV Module

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Kelsey A. W.; Woodhouse, Michael; Lee, Hohyun; Smestad, Greg P.

    2016-03-31

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.59/W(DC) manufacturing costs for our model HCPV module design with today's capabilities, and find that reducing cell costs and increasing module efficiency offer the most promising paths for future cost reductions. Cell costs could be significantly reduced via substrate reuse and improved manufacturing yields.

  4. Bottom-up graphene-nanoribbon fabrication reveals chiral edges and enantioselectivity.

    Science.gov (United States)

    Han, Patrick; Akagi, Kazuto; Federici Canova, Filippo; Mutoh, Hirotaka; Shiraki, Susumu; Iwaya, Katsuya; Weiss, Paul S; Asao, Naoki; Hitosugi, Taro

    2014-09-23

    We produce precise chiral-edge graphene nanoribbons on Cu{111} using self-assembly and surface-directed chemical reactions. We show that, using specific properties of the substrate, we can change the edge conformation of the nanoribbons, segregate their adsorption chiralities, and restrict their growth directions at low surface coverage. By elucidating the molecular-assembly mechanism, we demonstrate that our method constitutes an alternative bottom-up strategy toward synthesizing defect-free zigzag-edge graphene nanoribbons.

  5. 24 CFR 3285.804 - Bottom board repair.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Bottom board repair. 3285.804....804 Bottom board repair. (a) The bottom board covering must be inspected for any loosening or areas... to be replaced prior to closure and repair of the bottom board. (b) Any splits or tears in the...

  6. Bottomonia: open bottom strong decays and spectrum

    Directory of Open Access Journals (Sweden)

    Santopinto E.

    2014-05-01

    Full Text Available We present our results for the bottomonium spectrum with self energy corrections. The bare masses used in the calculation are computed within Godfrey and Isgur’s relativized quark model. We also discuss our results for the open bottom strong decay widths of higher bottomonia in the 3P0 pair-creation model.

  7. Spectroscopy and decays of charm and bottom

    Energy Technology Data Exchange (ETDEWEB)

    Butler, J.N.

    1997-10-01

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

  8. Bottom-up approach to silicon nanoelectronics

    OpenAIRE

    Mizumita, Hiroshi; Oda, S

    2005-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920) International audience This paper presents a brief review of our recent work investigating a novel bottom-up approach to realize silicon based nanoelectronics. We discuss fabrication technique, electronic properties and device applications of silicon nanodots as a building block for nanoscale silicon devices.

  9. CEOs: Gulf crisis hits hospitals' bottom line.

    Science.gov (United States)

    Johnsson, J

    1990-12-01

    Hospital CEOs say the Persian Gulf crisis could hit them hard where it counts. In fact, hospitals are already seeing some adverse impact from events in the Middle East. From fundraising to plant management to strategic planning, the confrontations in the Gulf are having an impact on the hospital's bottom line.

  10. Spectroscopy and decays of charm and bottom

    International Nuclear Information System (INIS)

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays

  11. Coil in bottom part of splitter magnet

    CERN Multimedia

    1976-01-01

    Radiation-resistant coil being bedded into the bottom part of a splitter magnet. This very particular magnet split the beam into 3 branches, for 3 target stations in the West-Area. See Annual Report 1975, p.176, Figs.14 and 15.

  12. Bottom-up organic integrated circuits

    NARCIS (Netherlands)

    Smits, Edsger C. P.; Mathijssen, Simon G. J.; van Hal, Paul A.; Setayesh, Sepas; Geuns, Thomas C. T.; Mutsaers, Kees A. H. A.; Cantatore, Eugenio; Wondergem, Harry J.; Werzer, Oliver; Resel, Roland; Kemerink, Martijn; Kirchmeyer, Stephan; Muzafarov, Aziz M.; Ponomarenko, Sergei A.; de Boer, Bert; Blom, Paul W. M.; de Leeuw, Dago M.

    2008-01-01

    Self- assembly - the autonomous organization of components into patterns and structures(1) - is a promising technology for the mass production of organic electronics. Making integrated circuits using a bottom- up approach involving self- assembling molecules was proposed(2) in the 1970s. The basic b

  13. 2004 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  14. 2002 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  15. 2005 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  16. 2001 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  17. 2007 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  18. 2003 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  19. 2006 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  20. Cathodic protection for the bottoms of above ground storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, John P. [Tyco Adhesives, Norwood, MA (United States)

    2004-07-01

    Impressed Current Cathodic Protection has been used for many years to protect the external bottoms of above ground storage tanks. The use of a vertical deep ground bed often treated several bare steel tank bottoms by broadcasting current over a wide area. Environmental concerns and, in some countries, government regulations, have introduced the use of dielectric secondary containment liners. The dielectric liner does not allow the protective cathodic protection current to pass and causes corrosion to continue on the newly placed tank bottom. In existing tank bottoms where inadequate protection has been provided, leaks can develop. In one method of remediation, an old bottom is covered with sand and a double bottom is welded above the leaking bottom. The new bottom is welded very close to the old bottom, thus shielding the traditional cathodic protection from protecting the new bottom. These double bottoms often employ the use of dielectric liner as well. Both the liner and the double bottom often minimize the distance from the external tank bottom. The minimized space between the liner, or double bottom, and the bottom to be protected places a challenge in providing current distribution in cathodic protection systems. This study examines the practical concerns for application of impressed current cathodic protection and the types of anode materials used in these specific applications. One unique approach for an economical treatment using a conductive polymer cathodic protection method is presented. (author)

  1. Dynamics of sea ice in the Baltic Sea and applications

    Science.gov (United States)

    Leppäranta, M.; Andrejev, O.; Oikkonen, A.

    2009-04-01

    Sea ice forms in the Baltic Sea annually. Coastal and archipelago areas are covered by landfast ice, while further offshore the ice drifts under the influence of winds and currents. The length scale of the Baltic Sea basins is 100 km and the scale of the ice thickness is ½ m, and the characteristics of the ice dynamics are similar to the ice dynamics in the polar seas. The drifting of the ice has major practical implications. First, the navigation conditions are determined by the ice extent, presence of leads and ice pressure, and therefore the dynamical behaviour of ice may cause rapid changes for them. Recent research has focused on ice kinematics scales, evolution of landfast ice zone, and downscaling of pressure from mesoscale models to ship scales. The length scale of dynamics depends on the ice thickness showing up in the stiffness of the ice and expansion of the landfast ice zone. Oil spills are in particular difficult in drift ice conditions, which has led to development of oil spill drift and dispersion models. This is most critical in the Gulf of Finland, a narrow and shallow basin with large oil terminals in the eastern side. The formation of sea ice ridges has important consequences in shallow basins since they ground to scour the bottom and form tie points for the expansion of the landfast ice.

  2. Excited bottom and bottom-strange mesons in the quark model

    Science.gov (United States)

    Lü, Qi-Fang; Pan, Ting-Ting; Wang, Yan-Yan; Wang, En; Li, De-Min

    2016-10-01

    In order to understand the possible q q ¯ quark-model assignments of the BJ(5840 ) and BJ(5960 ) recently reported by the LHCb Collaboration, we evaluate mass spectra, strong decays, and radiative decays of bottom and bottom-strange mesons in a nonrelativistic quark model. Comparing these predictions with the relevant experimental results, we suggest that the BJ(5840 ) and BJ(5960 ) can be identified as the B (2 1S0) and B (1 3D3) , respectively, and the B (5970 ) reported by the CDF Collaboration can be interpreted as the B (2 3S1) or B (1 3D3) . Further precise measurements of the width, spin and decay modes of the B (5970 ) are needed to distinguish these two assignments. These predictions of bottom and bottom-strange mesons can provide useful information to further experimental investigations.

  3. Excited bottom and bottom-strange mesons in the quark model

    CERN Document Server

    Lü, Qi-Fang; Wang, Yan-Yan; Wang, En; Li, De-Min

    2016-01-01

    In order to understand the possible $q\\bar{q}$ quark-model assignments of the $B_J(5840)$ and $B_J(5960)$ recently reported by the LHCb Collaboration, we evaluate mass spectra, strong decays, and radiative decays of bottom and bottom-strange mesons in a nonrelativistic quark model. Comparing these predictions with the relevant experimental results, we suggest that the $B_J(5840)$ and $B_J(5960)$ can be identified as $B(2^1S_0)$ and $B(1^3D_3)$, respectively, and the $B(5970)$ reported by the CDF Collaboration can be interpreted as $B(2^3S_1)$ or $B(1^3D_3)$. Further precise measurements of the width, spin and decay modes of the $B(5970)$ are needed to distinguish these two assignments. These predictions of bottom and bottom-strange mesons can provide useful information to further experimental investigations.

  4. Measurement of bottom-reflected sound in bottom-limited propagation environment

    Science.gov (United States)

    Hahn, Jooyoung; Park, Joungsoo

    2016-07-01

    To study the bottom reflection of underwater acoustic sound in a bottom-limited propagation environment, an experiment was conducted using four transmitting sounds in the form of a continuous wave from 1 to 6 kHz. The site of the experiment was a continental shelf region off the east coast of Korea where the bottom was composed of sandy mud. The mean water depth was 1100 m in the experiment area. Oceanographic data and acoustic data were collected simultaneously during the experiment. It was found that the sound pressure level decreased by 90 dB to 3.4 km and there is little frequency dependence because a strong direct path contributes more than a bottom-reflected path in sound pressure level. At a range between 6 and 7 km, there is a strong bottom-reflected ray path and frequency dependence exists because the bottom reflection loss varies with frequency at a given grazing angle. Sound pressure levels increase as the range increases between 6 and 7 km by 5.4, 1.9, 1.7, and 1.5 dB at frequencies of 1000, 2490, 3990, and 5490 Hz, respectively.

  5. Brine-induced advection of dissolved aromatic hydrocarbons to arctic bottom waters

    International Nuclear Information System (INIS)

    Extruded brine, generated during sea ice formation in nearshore arctic waters, will sink to the bottom and can form a stable bottom boundary layer. This layer can persist for periods of up to 4-6 months. Limited quantities of dissolved aromatic hydrocarbons resulting from a spill of crude oil or refined petroleum distillate products during periods of ice growth can be transported as conservative components to the benthos with sinking brine. Once incorporated into the stable bottom boundary layer, these aromatic components are no longer subject to loss by evaporative processes, and they only can be diluted by ultimately mixing with uncontaminated water masses, a process that proceeds slowly throughout the ice-covered period. This mechanism for the transport of dissolved hydrocarbons has been demonstrated through a laboratory test-tank simulation and a chemical/physical oceanographic field program conducted in the Chukchi Sea near Pt. Frankline, AK (March 1985). The results are pertinent to shallow nearshore oil and gas exploration, development, production, and transportation activities in high latitude marine systems

  6. Stabilization of bottom sediments from Rzeszowski Reservoir

    Directory of Open Access Journals (Sweden)

    Koś Karolina

    2015-06-01

    Full Text Available The paper presents results of stabilization of bottom sediments from Rzeszowski Reservoir. Based on the geotechnical characteristics of the tested sediments it was stated they do not fulfill all the criteria set for soils in earth embankments. Therefore, an attempt to improve their parameters was made by using two additives – cement and lime. An unconfined compressive strength, shear strength, bearing ratio and pH reaction were determined on samples after different time of curing. Based on the carried out tests it was stated that the obtained values of unconfined compressive strength of sediments stabilized with cement were relatively low and they did not fulfill the requirements set by the Polish standard, which concerns materials in road engineering. In case of lime stabilization it was stated that the tested sediments with 6% addition of the additive can be used for the bottom layers of the improved road base.

  7. Constructing bottom barriers with met grouting

    Energy Technology Data Exchange (ETDEWEB)

    Shibazaki, M.; Yoshida, H. [Chemical Grouting Company, Tokyo (Japan)

    1997-12-31

    Installing a bottom barrier using conventional high pressure jetting technology and ensuring barrier continuity is challenging. This paper describes technology that has been developed and demonstrated for the emplacement of bottom barriers using pressures and flow rates above the conventional high pressure jetting parameters. The innovation capable of creating an improved body exceeding 5 meters in diameter has resulted in the satisfying connection and adherence between the treated columns. Besides, the interfaces among the improved bodies obtain the same strength and permeability lower than 1 x 10{sup -7} cm/sec as body itself. A wide variety of the thickness and the diameter of the improved mass optimizes the application, and the method is nearing completion. The paper explains an aspect and briefs case histories.

  8. Race-To-The-Bottom Tariff Cutting

    OpenAIRE

    Vézina, Pierre-Louis

    2010-01-01

    This paper provides an empirical assessment of race-to-the-bottom unilateralism. It suggests that decades of unilateral tariff cutting in Asia's emerging economies have been driven by a competition to attract FDI from Japan. Using spatial econometrics, I show that tariffs on parts and components, a crucial locational determinant for Japanese firms, converged across countries following a contagion pattern. Tariffs followed those of competing countries if the latter were lower, if FDI jealousy ...

  9. How Service Innovation Boosts Bottom Lines

    OpenAIRE

    Claude Legrand; Rob LaJoie

    2013-01-01

    In the national quest for ground-breaking R&D discoveries and inventions, service innovation is frequently ignored at considerable cost to an organization’s bottom line and a nation’s productivity. For the fact is that innovation applied systematically to all activities outside of R&D can make the difference between uninspiring results and substantial growth in every sector. Many countries, in particular in Europe, have recognized the importance of service innovation and are devoting consider...

  10. Bottoming out-Sign of Stabilization

    Institute of Scientific and Technical Information of China (English)

    Dennis K. Zhao

    2009-01-01

    @@ Production Rose from its Nadir Apart from individual data report.CNTAC was a lot more focused on an overall review of textile industry as a whole to illustrate economic behavior for the first five months."sign of stabilization,bottoming out"are the key words emphatically voiced as a token of encou ragement,for the important economic indexes are indeed encouraging as compa red with this fi rst quarter.

  11. Bottom-strange mesons in hyperonic matter

    CERN Document Server

    Pathak, Divakar

    2014-01-01

    The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in-medium interactions are similar to those observed for the strange-charmed mesons in a preceding investigation, such as the lifting of mass-degeneracy of $B_S^0$ and ${\\bar B}_S^0$ mesons in hyperonic matter, while the same is respected in vacuum as well as in nuclear matter. In general, however, there is a remarkable distinction between the two species, even though the formalism predicts a completely analogous in-medium...

  12. Optimal Design of Round Bottomed Triangle Channels

    Directory of Open Access Journals (Sweden)

    Ayman T. Hameed

    2013-05-01

    Full Text Available     In optimal design concept, the geometric dimensions of a channel cross-section are determined in a manner to minimize the total construction costs. The Direct search optimization method by using MATALAB is used to solve the resulting channel optimization models for a specified flow rate, roughness coefficient and longitudinal slope. The developed optimization models are applied to design the round bottomed triangle channel and trapezoidal channels to convey a given design flow considering various design scenarios However, it also can be extended to other shapes of channels. This method optimizes the total construction cost by minimizing the cross-sectional area and wetted perimeter per unit length of the channel. In the present study, it is shown that for all values of side slope, the total construction cost in the round bottomed triangle cross-section are less than those of trapezoidal cross-section for the same values of discharge. This indicates that less excavation and a lining are involved and therefore implies that the round bottomed triangle cross-section is more economical than trapezoidal cross-section.

  13. Capacitive Substrate Coupling of Row–Column-Addressed 2-D CMUT Arrays

    DEFF Research Database (Denmark)

    Engholm, Mathias; Bouzari, Hamed; Jensen, Jørgen Arendt;

    2016-01-01

    the semiconductor substrate. To reduce the parasitic capacitance by 80% the bulk doping concentration should be at most 1012 cm-3. Experimental results show that the parasitic capacitance can be reduced by 87% by applying a substrate potential of 6V relative to the bottom electrodes. The depletion......Row–column-addressed CMUT arrays suffer from low receive sensitivity of the bottom elements due to a capacitive coupling to the substrate. The capacitive coupling increases the parasitic capacitance. A simple approach to reduce the parasitic capacitance is presented, which is based on depleting...... of the semiconductor substrate can be sustained for at least 10 minutes making it applicable for row–column-addressed CMUT arrays for ultrasonic imaging. Theoretically the reduced parasitic capacitance indicates that the receive sensitivity of the bottom elements can be increased by a factor of 2:1....

  14. Report from a cruise onboard RV G. O. Sars 22.11 – 03.12.2008: Comparing the impact of two bottom trawls

    OpenAIRE

    Vold, Aud; Breen, Michael; Hansen, Kurt; Vincent, Benoit; Zachariassen, Kristian

    2009-01-01

    The final research cruise described in this report had the objective to compare the physical and biological impact of the bottom trawl modifications developed during the EU DEGREE project to a standard bottom trawl used in the Barents Sea cod fisheries. The “new” trawl was fitted with the last modification of the plate gear developed during the project as well as trawl doors (standard Thyborøn doors) rigged to barely touch the bottom. The commercial trawl used for comparison was rigged with a...

  15. Surface and bottom temperature and salinity climatology along the continental shelf off the Canadian and U.S. East Coasts

    Science.gov (United States)

    Richaud, Benjamin; Kwon, Young-Oh; Joyce, Terrence M.; Fratantoni, Paula S.; Lentz, Steven J.

    2016-08-01

    A new hydrographic climatology has been created for the continental shelf region, extending from the Labrador shelf to the Mid-Atlantic Bight. The 0.2-degree climatology combines all available observations of surface and bottom temperature and salinity collected between 1950 and 2010 along with the location, depth and date of these measurements. While climatological studies of surface and bottom temperature and salinity have been presented previously for various regions along the Canadian and U.S. shelves, studies also suggest that all these regions are part of one coherent system. This study focuses on the coherent structure of the mean seasonal cycle of surface and bottom temperature and salinity and its variation along the shelf and upper slope. The seasonal cycle of surface temperature is mainly driven by the surface heat flux and exhibits strong dependency on latitude (r≈-0.9). The amplitude of the seasonal cycle of bottom temperature is rather dependent on the depth, while the spatial distribution of bottom temperature is correlated with latitude. The seasonal cycle of surface salinity is influenced by several components, such as sea-ice on the northern shelves and river discharge in the Gulf of St. Lawrence. The bottom salinity exhibits no clear seasonal cycle, but its spatial distribution is highly correlated with bathymetry, thus Slope Water and its intrusion on the shelf can be identified by its relatively high salinity compared to shallow, fresher shelf water. Two different regimes can be identified, especially on the shelf, separated by the Laurentian Channel: advection influences the phasing of the seasonal cycle of surface salinity and bottom temperature to the north, while in the southern region, river runoff and air-sea heat flux forcing are dominant, especially over the shallower bathymetry.

  16. Significant anaerobic production of fluorescent dissolved organic matter in the deep East Sea (Sea of Japan)

    Science.gov (United States)

    Kim, Jeonghyun; Kim, Guebuem

    2016-07-01

    The distribution of fluorescent dissolved organic matter (FDOM) in the East Sea (Sea of Japan) was examined by excitation-emission matrix spectroscopy with parallel factor analysis (PARAFAC). Humic-like FDOM (FDOMH) increased with depth and was significantly correlated with Apparent Oxygen Utilization (AOU), indicating that FDOMH in the deep water is mainly produced by oxidation of organic matter. In addition, a surprisingly large excess of FDOMH relative to that expected from the observed AOU was found from 1000 m to the bottom (up to 3500 m). Based on the high-resolution geographical distribution and characteristics of FDOM in the East Sea, we conclude that this excess likely originates from anaerobic FDOMH production in subsurface bottom sediments. This FDOMH flux accounts for 8-15% of the total FDOM production in the water column. Our results suggest that anaerobic activities in subsurface sediments are an important hidden source of FDOM in the ocean.

  17. Mathematical Modeling of the Pressure Field Generated by Ocean Wave at the Bottom of the Ocean

    Institute of Scientific and Technical Information of China (English)

    龚沈光; 唐劲飞; 颜冰

    2002-01-01

    This paper develops a new method for calculating the pressure-tirme processof the pressure field generated by ocean wave at sea bottom based on the surface wavespectrum of the ocean wave. The basic assumptions of modeling are that the surfaceocean wave pressure equals to the atmospheric pressure and that the viscidity of seawater is neglected. The steps of modeling are described below. First the power spectraldensity of ocean wave is discretized and the amplitude spectra of harmonic ocean waveare obtained. Then the amplitude spectra of harmonic pressure are obtained accordingto the amplitude spectrum of surface wave and the depth of the sea. Finally, based onthe oceanographic theory of representing a fixed wave surface by summing up random-phase sinusoids, the pressure-time process of pressure field at sea bottom is obtained bysumming up the amplitude spectrum of pressure. The paper also develops a method ofdetermining the relationship between mean wave period and wave heights undershallow water condition, thus the pressure-time process of pressure field produced bynon-well-developed ocean wave can be directly calculated once the mean wave heightand period are known.

  18. Substrate Integrated Waveguide Fed Cavity Backed Slot Antenna for Circularly Polarized Application

    OpenAIRE

    Xiao Hong Zhang; Guo Qing Luo; Lin Xi Dong

    2013-01-01

    A novel planar low-profile cavity-backed slot antenna for circularly polarized applications is presented in this paper. The low-profile substrate integrated waveguide (SIW) cavity is constructed on a single PCB substrate with two metal layers on the top and the bottom surfaces and metallized via array through the substrate. The SIW cavity is fed by a SIW transmission line. The two orthogonal degenerate cavities resonance TM110 mode are successfully stimulated and separated. The circularly pol...

  19. Analysis of ADCP data above a bottom observatory

    Directory of Open Access Journals (Sweden)

    H. Gerber

    2006-06-01

    Full Text Available A 300-kHz ADCP was set on GEOSTAR, a six-m3 deep-sea observatory. It was operated with cells of 80 cm during a three-week test experiment at 42-m water depth in the northern Adriatic sub-basin. Although it provided valuable data about the horizontal current field over most of the water column, it also allowed specifying the wake disturbances induced by the observatory. These disturbances are characterised by vertical velocities that are significant up to ~20 m above seafloor (echo intensity data suggest that the wake can even reach the surface, and by inclinations of the bottom nepheloïd layer (as deduced from differences in echo intensities from beam to beam. Our analysis is validated by consistent relationships between the horizontal current direction and speed on one side and the characteristics of both dynamical (vertical velocity and non-dynamical (echo intensity parameters on the other side. It is in good agreement with the simulations from a numerical model, and hence specifies the sensitivity (especially with respect to echo intensity and accuracy of an instrument usually operated within fields of current and scatterers not disturbed by the device supporting it. In addition, the error velocity parameter displays specific characteristics that easily allow specifying the thickness of the layer disturbed by the observatory, thus providing a technique to validate the quality of data acquired in similar conditions.

  20. The microwave scattering characteristics of sea ice in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Meijie; DAI Yongshou; ZHANG Jie; ZHANG Xi; MENG Junmin; ZHU Xiuqin; YIN Yalei

    2016-01-01

    Microwave remote sensing has become the primary means for sea-ice research, and has been supported by a great deal of field experiments and theoretical studies regarding sea-ice microwave scattering. However, these studies have been barely carried in the Bohai Sea. The sea-ice microwave scattering mechanism was first developed for the thin sea ice with slight roughness in the Bohai Sea in the winter of 2012, and included the backscattering coefficients which were measured on the different conditions of three bands (L, C and X), two polarizations (HH and VV), and incident angles of 20° to 60°, using a ground-based scatterometer and the synchronous physical parameters of the sea-ice temperature, density, thickness, salinity, and so on. The theoretical model of the sea-ice electromagnetic scattering is obtained based on these physical parameters. The research regarding the sea-ice microwave scattering mechanism is carried out through two means, which includes the comparison between the field microwave scattering data and the simulation results of the theoretical model, as well as the feature analysis of the four components of the sea-ice electromagnetic scattering. It is revealed that the sea-ice microwave scattering data and the theoretical simulation results vary in the same trend with the incident angles. Also, there is a visible variant in the sensitivity of every component to the different bands. For example, the C and X bands are sensitive to the top surface, the X band is sensitive to the scatterers, and the L and C bands are sensitive to the bottom surface, and so on. It is suggested that the features of the sea-ice surfaces and scatterers can be retrieved by the further research in the future. This experiment can provide an experimental and theoretical foundation for research regarding the sea-ice microwave scattering characteristics in the Bohai Sea.

  1. The Pen Shell, Pinna nobilis: A Review of Population Status and Recommended Research Priorities in the Mediterranean Sea.

    Science.gov (United States)

    Basso, Lorena; Vázquez-Luis, Maite; García-March, José R; Deudero, Salud; Alvarez, Elvira; Vicente, Nardo; Duarte, Carlos M; Hendriks, Iris E

    2015-01-01

    The pen shell Pinna nobilis (also known as the fan mussel) is an endemic bivalve of the Mediterranean Sea. Threatened by human activities, it has been listed as an endangered and protected species under the European Council Directive 92/43/EEC since 1992. The ecological role of this species is of importance because it filters and retains large amounts of organic matter from suspended detritus contributing to water clarity. In addition, as a hard substrate in the soft-bottom seafloor, it provides a surface that can be colonized by other (floral and faunal) benthic species. Here, we provide an overview of all available published studies on the pen shell, compiling available data and summarizing current knowledge on the conservation status and viability of populations over the full range of the Mediterranean Basin. Additionally, we discuss the different practices in applied methodology and identify gaps and new research areas in order to render conservation programmes of the species more effective. PMID:26320617

  2. Carbon transformation and the sources of dissolved inorganic carbonate in sediments of a temperate coastal sea, the Baltic Sea: A stable isotope and modelling approach

    Science.gov (United States)

    Lipka, Marko; Liu, Bo; Wegwerth, Antje; Dellwig, Olaf; Winde, Vera; Al-Raei, Abdul M.; Böttcher, Michael E.

    2015-04-01

    Organic matter is mineralized in brackish-marine sediments by microbial activity using predominantly and sulfate as electron acceptors. Under anoxic bottom water conditions, sulfate reduction dominates. Pore water profiles reflect net biogeochemical processes, transformation rates and fluxes of dissolved species across the sediment-water interface. Element fluxes across the sediment-water interface are controlled by different boundary conditions. We present the results of a detailed biogeochemical investigation of interstitial waters from different sediments of the Baltic Sea covering the range of sedimentological and bottom water redox conditions. It was the aim to study the biogeochemical transformation processes and associated element fluxes at the sediment-water-interface and the role of organic matter or methane as potential substrates for microbial activity. Short sediment cores were collected during several research cruises with multicoring devices. Pore waters were analyzed for nutrients, major and trace element concentrations to allow a modelling of net volumetric transformation rates and diffusive element fluxes. Gross sulfate reduction rates were measured in selected cores using incubations with radiotracer. As a tracer for the source of dissolved inorganic carbonate (DIC) the carbon isotope composition was measured. A quantitative interpretation of vertical concentration profiles in the pore waters was performed using different modelling approaches. Element fluxes across the sediment-water interface show a dependence from bottom water redox conditions, sediment compositions, and sedimentation conditions. It is shown that the carbon isotope composition of DIC is a valuable and sensitive parameter in a model-based estimate of the impact of biological and physical mixing of surface sediments. Research is supported by German BMBF within the KÜNO-SECOS project and Leibniz IOW

  3. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    Science.gov (United States)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  4. The impact of coastal defence structures (tetrapods) on decapod crustaceans in the southern North Sea.

    Science.gov (United States)

    Wehkamp, Stephanie; Fischer, Philipp

    2013-12-01

    Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions. PMID:24041979

  5. Study on linear and nonlinear bottom friction parameterizations for regional tidal models using data assimilation

    Science.gov (United States)

    Zhang, Jicai; Lu, Xianqing; Wang, Ping; Wang, Ya Ping

    2011-04-01

    Data assimilation technique (adjoint method) is applied to study the similarities and the differences between the Ekman (linear) and the Quadratic (nonlinear) bottom friction parameterizations for a two-dimensional tidal model. Two methods are used to treat the bottom friction coefficient (BFC). The first method assumes that the BFC is a constant in the entire computation domain, while the second applies the spatially varying BFCs. The adjoint expressions for the linear and the nonlinear parameterizations and the optimization formulae for the two BFC methods are derived based on the typical Largrangian multiplier method. By assimilating the model-generated 'observations', identical twin experiments are performed to test and validate the inversion ability of the presented methodology. Four experiments, which employ the linear parameterization, the nonlinear parameterizations, the constant BFC and the spatially varying BFC, are carried out to simulate the M 2 tide in the Bohai Sea and the Yellow Sea by assimilating the TOPEX/Poseidon altimetry and tidal gauge data. After the assimilation, the misfit between model-produced and observed data is significantly decreased in the four experiments. The simulation results indicate that the nonlinear Quadratic parameterization is more accurate than the linear Ekman parameterization if the traditional constant BFC is used. However, when the spatially varying BFCs are used, the differences between the Ekman and the Quadratic approaches diminished, the reason of which is analyzed from the viewpoint of dissipation rate caused by bottom friction. Generally speaking, linear bottom friction parameterizations are often used in global tidal models. This study indicates that they are also applicable in regional ocean tidal models with the combination of spatially varying parameters and the adjoint method.

  6. Vector-like bottom quarks in composite Higgs models

    DEFF Research Database (Denmark)

    Gillioz, M.; Grober, R.; Kapuvari, A.;

    2014-01-01

    , and we test the compatibility with the electroweak precision observables. In particular we evaluate the constraint from the Z coupling to left-handed bottom quarks. General formulae have been derived which include the effects of new bottom partners in the loop corrections to this coupling and which can...... of the left-handed top and bottom quarks....

  7. BENTHIC FORAMINIFERA AS INDICATORS OF PALEOECOLOGICAL BOTTOM CONDITIONS IN THE SERRAVALLIAN TREMITI SECTIONS (EASTERN MEDITERRANEAN, ITALY

    Directory of Open Access Journals (Sweden)

    BIANCA RUSSO

    2002-07-01

    Full Text Available Quantitative analysis of  benthic foraminifera from the Serravallian S. Nicola composite section (Tremiti Islands, Adriatic Sea and about 37 m thick, pointed out changes of bottom paleoecological conditions in this eastern Mediterranean area during the analyzed time interval. Benthic foraminiferal assemblages are typical of bathyal environment and indicate a constant paleobathymetry of about 1,000 m. Changes in benthic foraminiferal assemblages allowed us to identify five intervals,  which were calibrated on the astrochronological scale to reconstruct paleoecological evolution of bottom conditions. In particular starting from the base of the section the following different bottom conditions have been identified: 1 between about 12.62  to about 12.29 Ma high surface productivity, active bottom water circulation and, consequently, moderate bottom food supply; this paleoenvironment slightly changed  between about 12.49 and 12.29 Ma, where benthic assemblages testify unstable bottom conditions with periods of active circulation (relative abundance of Cibicidoides wuellerstorfi, alternated with periods of sluggish circulation  (peaks of Bulimina subulata group; 2 relatively oxygenated paleoenvironment together with low food supply between about  12.29 - 12.08 Ma; 3 increase of organic matter content (abundance of  U. peregrina-pygmaea, due to higher surface productivity and/or greater preservation of organic matter at bottom from 12.08 to 11.81 Ma; 4 relatively oxygenated conditions with low food supply from 11.81 to about 11.45 Ma; 5 similar conditions to those of the basal part (about 12.62  - 12.29 Ma of the section from about 11.45 to 11.10 Ma, but with an increase of organic matter content. Finally, the comparison between the paleoecological reconstruction of the S. Nicola composite section and Ras il-Pellegrin (Malta composite section (reported in this volume in  the interval between about 12.6 and 12.2 Ma, pointed out very different

  8. Observations of near-bottom currents in Bornholm Basin, Slupsk Furrow and Gdansk Deep

    Science.gov (United States)

    Bulczak, A. I.; Rak, D.; Schmidt, B.; Beldowski, J.

    2016-06-01

    Dense bottom currents are responsible for transport of the salty inflow waters from the North Sea driving ventilation and renewal of Baltic deep waters. This study characterises dense currents in three deep locations of the Baltic Proper: Bornholm Basin (BB), Gdansk Basin (GB) and Slupsk Furrow (SF). These locations are of fundamental importance for the transport and pollution associated with chemical munitions deposited in BB and GB after 2nd World War. Of further importance the sub-basins are situated along the pathway of dense inflowing water.Current velocities were measured in the majority of the water column during regular cruises of r/v Oceania and r/v Baltica in 2001-2012 (38 cruises) by 307 kHz vessel mounted (VM), downlooking ADCP. Additionally, the high-resolution CTD and oxygen profiles were collected. Three moorings measured current velocity profiles in SF and GB over the summer 2012. In addition, temperature, salinity, oxygen and turbidity were measured at about 1 m above the bottom in GB. The results showed that mean current speed across the Baltic Proper was around 12 cm s-1 and the stronger flow was characteristic to the regions located above the sills, in the Bornholm and Slupsk Channels, reaching on average about 20 cm s-1. The results suggest that these regions are important for the inflow of saline waters into the eastern Baltic and are the areas of intense vertical mixing. The VM ADCP observations indicate that the average near-bottom flow across the basin can reach 35±6 cm s-1. The mooring observations also showed similar near-bottom flow velocities. However, they showed that the increased speed of the near-bottom layer occurred frequently in SF and GB during short time periods lasting for about few to several days or 10-20% of time. The observations showed that the bottom mixed layer occupies at least 10% of the water column and the turbulent mixing induced by near-bottom currents is likely to produce sediment resuspension and transport

  9. Factors governing the deep ventilation of the Red Sea

    KAUST Repository

    Papadopoulos, Vassilis P.

    2015-11-19

    A variety of data based on hydrographic measurements, satellite observations, reanalysis databases, and meteorological observations are used to explore the interannual variability and factors governing the deep water formation in the northern Red Sea. Historical and recent hydrographic data consistently indicate that the ventilation of the near-bottom layer in the Red Sea is a robust feature of the thermohaline circulation. Dense water capable to reach the bottom layers of the Red Sea can be regularly produced mostly inside the Gulfs of Aqaba and Suez. Occasionally, during colder than usual winters, deep water formation may also take place over coastal areas in the northernmost end of the open Red Sea just outside the Gulfs of Aqaba and Suez. However, the origin as well as the amount of deep waters exhibit considerable interannual variability depending not only on atmospheric forcing but also on the water circulation over the northern Red Sea. Analysis of several recent winters shows that the strength of the cyclonic gyre prevailing in the northernmost part of the basin can effectively influence the sea surface temperature (SST) and intensify or moderate the winter surface cooling. Upwelling associated with periods of persistent gyre circulation lowers the SST over the northernmost part of the Red Sea and can produce colder than normal winter SST even without extreme heat loss by the sea surface. In addition, the occasional persistence of the cyclonic gyre feeds the surface layers of the northern Red Sea with nutrients, considerably increasing the phytoplankton biomass.

  10. A new kind of bottom quark factory

    International Nuclear Information System (INIS)

    We describe a novel method of producing large numbers of B mesons containing bottom quarks. It is known that one should analyze at least 109 B meson decays to elucidate the physics of CP violation and rare B decay modes. Using the ultra high energy electron beams from the future generation of electron linear colliders, we Compton backscatter low energy laser beams off these electron beams. From this process, we produce hot photons having energy hundreds of GeV. Upon scattering these hot photons onto stationary targets, we show that it is possible to photoproduce and measure the necessary 109 B mesons per year. 24 refs., 4 figs

  11. Control Properties of Bottom Fired Marine Boilers

    DEFF Research Database (Denmark)

    Solberg, Brian; Andersen, Palle; Karstensen, Claus M. S.

    2007-01-01

    This paper focuses on model analysis of a dynamic model of a bottom fired one-pass smoke tube boiler. Linearized versions of the model are analyzed and show large variations in system gains at steady state as function of load whereas gain variations near the desired bandwidth are small. An analysis...... showed substantial improvement compared to a decentralized scheme based on sequential loop closing. Similar or better result is expected to be obtainable using a full Multiple input Multiple output scheme. Furthermore closed loop simulations, applying a linear controller to the nonlinear plant model...... on states and control signals should be considered....

  12. Rankine bottoming cycle safety analysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, G.A.

    1980-02-01

    Vector Engineering Inc. conducted a safety and hazards analysis of three Rankine Bottoming Cycle Systems in public utility applications: a Thermo Electron system using Fluorinal-85 (a mixture of 85 mole % trifluoroethanol and 15 mole % water) as the working fluid; a Sundstrand system using toluene as the working fluid; and a Mechanical Technology system using steam and Freon-II as the working fluids. The properties of the working fluids considered are flammability, toxicity, and degradation, and the risks to both plant workers and the community at large are analyzed.

  13. Numerical Modeling on Hydrodynamic Performance of A Bottom-Hinged Flap Wave Energy Converter

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hai-tao; SUN Zhi-lin; HAO Chun-ling; SHEN Jia-fa

    2013-01-01

    The hydrodynamic performance of a bottom-hinged flap wave energy converter (WEC) is investigated through a frequency domain numerical model.The numerical model is verified through a two-dimensional analytic solution,as well as the qualitative analysis on the dynamic response of avibrating system.The concept of "optimum density" of the bottom-hinged flap is proposed,and its analytic expression is derived as well.The frequency interval in which the optimum density exists is also obtained.The analytic expression of the optimum linear damping coefficient is obtained by a bottom-hinged WEC.Some basic dynamic properties involving natural period,excitation moment,pitch amplitude,and optimum damping coefficient are analyzed and discussed in detail.In addition,this paper highlights the analysis of effects on the conversion performance of the device exerted by some important parameters.The results indicate that "the optimum linear damping period of 5.0 s" is the most ideal option in the short wave sea states with the wave period below 6.0 s.Shallow water depth,large flap thickness and low flap density are advised in the practical design of the device in short wave sea states in order to maximize power capture.In the sea state with water depth of 5.0 m and wave period of 5.0 s,the results of parametric optimization suggest a flap with the width of 8.0 m,thickness of 1.6 m,and with the density as little as possible when the optimum power take-off (PTO) damping coefficient is adopted.

  14. Sea level trends in South East Asian Seas (SEAS

    Directory of Open Access Journals (Sweden)

    M. W. Strassburg

    2014-10-01

    Full Text Available Southeast Asian Seas (SEAS span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

  15. Numerical study on spatially varying bottom friction coefficient of a 2D tidal model with adjoint method

    Science.gov (United States)

    Lu, Xianqing; Zhang, Jicai

    2006-10-01

    Based on the simulation of M2 tide in the Bohai Sea, the Yellow Sea and the East China Sea, TOPEX/Poseidon altimeter data are assimilated into a 2D tidal model to study the spatially varying bottom friction coefficient (BFC) by using the adjoint method. In this study, the BFC at some grid points are selected as the independent BFC, while the BFC at other grid points can be obtained through linear interpolation with the independent BFC. Two strategies for selecting the independent BFC are discussed. In the first strategy, one independent BFC is uniformly selected from each 1°×1° area. In the second one, the independent BFC are selected based on the spatial distribution of water depth. Twin and practical experiments are carried out to compare the two strategies. In the twin experiments, the adjoint method has a strong ability of inverting the prescribed BFC distributions combined with the spatially varying BFC. In the practical experiments, reasonable simulation results can be obtained by optimizing the spatially varying independent BFC. In both twin and practical experiments, the simulation results with the second strategy are better than those with the first one. The BFC distribution obtained from the practical experiment indicates that the BFC in shallow water are larger than those in deep water in the Bohai Sea, the North Yellow Sea, the South Yellow Sea and the East China Sea individually. However, the BFC in the East China Sea are larger than those in the other areas perhaps because of the large difference of water depth or bottom roughness. The sensitivity analysis indicates that the model results are more sensitive to the independent BFC near the land.

  16. There is plenty of oil at the bottom: Frontier thinking in knowledge economy

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    This paper will neither celebrate nor criticize knowledge economy but simply ask what it can do. What kinds of knowledge claims can be made in a research project where science, industry and government interests are closely intertwined? Based on ethnographic fieldwork and interviews with scientists...... of frontier-thinking which works to create a promissory space for future value creation. When viewed from the nano scale, the North Sea oil fields seem half full rather than half empty. There is plenty of oil at the bottom of the ocean if one knows how to look and future oil recovery might become analogous...

  17. Weighing the ocean with bottom-pressure sensors: robustness of the ocean mass annual cycle estimate

    OpenAIRE

    Williams, Joanne; Hughes, C. W.; Tamisiea, M. E; Williams, S. D. P.

    2014-01-01

    We use ocean bottom-pressure measurements from 17 tropical sites to determine the annual cycle of ocean mass. We show that such a calculation is robust, and use three methods to estimate errors in the mass determination. Our final best estimate, using data from the best sites and two ocean models, is that the annual cycle has an amplitude of 0.85 mbar (equivalent to 8.4 mm of sea level, or 3100 Gt of water), with a 95% chance of lying within the range 0.61–1.17 mbar. The time of the peak in o...

  18. Oil and gas platforms with steam bottoming cycles: System integration and thermoenvironomic evaluation

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Tock, Laurence; Breuhaus, Peter;

    2014-01-01

    cooling utility, and (iv) the weight limitations on the platform are quantitatively assessed. The results illustrate the benefits of converting the gas turbine process into a combined cycle, since the fuel gas consumption and the total CO2-emissions can be reduced by more than 15 %. Using the cooling......The integration of steam bottoming cycles on oil and gas platforms is currently regarded as the most promising option for improving the performance of these energy-intensive systems. In this paper, a North Sea platform is taken as case study, and a systematic analysis of its energy requirements...

  19. Charmed bottom baryon spectroscopy from lattice QCD

    CERN Document Server

    Brown, Zachary S; Meinel, Stefan; Orginos, Kostas

    2014-01-01

    We calculate the masses of baryons containing one, two, or three heavy quarks using lattice QCD. We consider all possible combinations of charm and bottom quarks, and compute a total of 36 different states with $J^P = \\frac12^+$ and $J^P = \\frac32^+$. We use domain-wall fermions for the up, down, and strange quarks, a relativistic heavy-quark action for the charm quarks, and nonrelativistic QCD for the bottom quarks. Our analysis includes results from two different lattice spacings and seven different pion masses. We perform extrapolations of the baryon masses to the continuum limit and to the physical pion mass using $SU(4|2)$ heavy-hadron chiral perturbation theory including $1/m_Q$ and finite-volume effects. For the 14 singly heavy baryons that have already been observed, our results agree with the experimental values within the uncertainties. We compare our predictions for the hitherto unobserved states with other lattice calculations and quark-model studies.

  20. The petroleum industry improving the bottom line

    International Nuclear Information System (INIS)

    The oil and gas exploration and production business environment has presented many challenges over the last decade, notably price volatility and rising costs. Managing the margin and changing a company's cost structure to improve the bottom line is a major issue with company executives. The experiences of Oryx Energy Company since its spinoff from Sun Company in 1988 are used as an example of a company makeover. A generalized exploration and production income statement is employed to present industry cost/portfolio relationships and strategies for improving the bottom line. At Oryx, three major strategies were set in place to enhance shareholder value: an increased emphasis on applied technology, including horizontal drilling, advanced 3-dimensional seismic prospecting, and intensive use of interactive computer workstations; international expansion; and an emphasis on the U.S. Gulf of Mexico, deemphasizing the onshore U.S. and the gas processing business. Specific strategies are outlined in the areas of increasing revenues, reducing production cost and exploration expense, and controlling general and administrative expenses. 8 refs., 18 figs., 2 tabs

  1. Long Wave Dynamics along a Convex Bottom

    CERN Document Server

    Didenkulova, Ira; Soomere, Tarmo

    2008-01-01

    Long linear wave transformation in the basin of varying depth is studied for a case of a convex bottom profile in the framework of one-dimensional shallow water equation. The existence of travelling wave solutions in this geometry and the uniqueness of this wave class is established through construction of a 1:1 transformation of the general 1D wave equation to the analogous wave equation with constant coefficients. The general solution of the Cauchy problem consists of two travelling waves propagating in opposite directions. It is found that generally a zone of a weak current is formed between these two waves. Waves are reflected from the coastline so that their profile is inverted with respect to the calm water surface. Long wave runup on a beach with this profile is studied for sine pulse, KdV soliton and N-wave. Shown is that in certain cases the runup height along the convex profile is considerably larger than for beaches with a linear slope. The analysis of wave reflection from the bottom containing a s...

  2. Bottom-up holographic approach to QCD

    International Nuclear Information System (INIS)

    One of the most known result of the string theory consists in the idea that some strongly coupled gauge theories may have a dual description in terms of a higher dimensional weakly coupled gravitational theory — the so-called AdS/CFT correspondence or gauge/gravity correspondence. The attempts to apply this idea to the real QCD are often referred to as “holographic QCD” or “AdS/QCD approach”. One of directions in this field is to start from the real QCD and guess a tentative dual higher dimensional weakly coupled field model following the principles of gauge/gravity correspondence. The ensuing phenomenology can be then developed and compared with experimental data and with various theoretical results. Such a bottom-up holographic approach turned out to be unexpectedly successful in many cases. In the given short review, the technical aspects of the bottom-up holographic approach to QCD are explained placing the main emphasis on the soft wall model

  3. Bottom-up holographic approach to QCD

    Energy Technology Data Exchange (ETDEWEB)

    Afonin, S. S. [V. A. Fock Department of Theoretical Physics, Saint Petersburg State University, 1 ul. Ulyanovskaya, 198504 (Russian Federation)

    2016-01-22

    One of the most known result of the string theory consists in the idea that some strongly coupled gauge theories may have a dual description in terms of a higher dimensional weakly coupled gravitational theory — the so-called AdS/CFT correspondence or gauge/gravity correspondence. The attempts to apply this idea to the real QCD are often referred to as “holographic QCD” or “AdS/QCD approach”. One of directions in this field is to start from the real QCD and guess a tentative dual higher dimensional weakly coupled field model following the principles of gauge/gravity correspondence. The ensuing phenomenology can be then developed and compared with experimental data and with various theoretical results. Such a bottom-up holographic approach turned out to be unexpectedly successful in many cases. In the given short review, the technical aspects of the bottom-up holographic approach to QCD are explained placing the main emphasis on the soft wall model.

  4. Heavy Exotic Molecules with Charm and Bottom

    CERN Document Server

    Liu, Yizhuang

    2016-01-01

    We revisit the formation of pion-mediated heavy-light exotic molecules with both charm and bottom and their chiral partners under the general strictures of both heavy-quark and chiral symmetry. The chiral exotic partners with good parity formed using the $(0^+, 1^+)$ multiplet are about twice more bound than their primary exotic partners formed using the $(0^-,1^-)$ multiplet. The chiral couplings across the multiplets $(0^\\pm, 1^\\pm)$ cause the chiral exotic partners to unbind, and the primary exotic molecules to be about twice more bound, for $J\\leq 1$. Our multi-channel coupling results show that only the charm isosinglet exotic molecules with $J^{PC}=1^{++}$ binds, which we identify as the reported neutral $X(3872)$. Also, the bottom isotriplet exotic with $J^{PC}=1^{+-}$ binds, which we identify as a mixture of the reported charged exotics $Z^+_b(10610)$ and $Z^+_b(10650)$. The bound isosinglet with $J^{PC}=1^{++}$ is suggested as a possible neutral $X_b(10532)$ not yet reported.

  5. Multibaryons with strangeness, charm and bottom

    Energy Technology Data Exchange (ETDEWEB)

    Kopeliovich, V.B. [Rossijskaya Akademiya Nauk, Moscow (Russian Federation). Inst. Yadernykh Issledovanij; Durham Univ. (United Kingdom). Dept. of Mathematical Sciences; Zakrzewski, W.J. [Durham Univ. (United Kingdom). Dept. of Mathematical Sciences

    2000-12-01

    The spectra of baryonic systems with strangeness, charm and bottom are considered within a ''rigid oscillator'' version of the bound state soliton model. The static properties of multiskyrmions, of baryon number up to B=8, are calculated using the recently suggested rational map ansaetze as starting field configurations. The property of binding of flavoured mesons by an SU(2) skyrmion is proved rigorously within this model. Binding energy estimates are made of the states with largest isospin which can appear as negatively charged nuclear fragments and for states with zero isospin - fragments of ''flavoured'' nuclear matter. It is shown that for all types of flavour and for vertical stroke F vertical stroke {<=}2 the isoscalar baryonic systems have a better chance to be stable against strong and electromagnetic interactions than those with nonzero isospin. Baryonic systems with charm or bottom quantum numbers are found to be bound more than strange baryonic systems. (orig.)

  6. Bottom-up tailoring of photonic nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Madsen, Morten; Frese, Ralf;

    2008-01-01

    Aligned ensembles of nanoscopic nanofibers from organic molecules such as para-phenylenes for photonic applications can be fabricated by self-assembled molecular growth on a suited dielectric substrate. Epitaxy together with alignment due to electric surface fields determines the growth directions...

  7. Demersal Assemblages on the Soft Bottoms off the Catalan-Levante Coast of the Spanish Mediterranean

    Directory of Open Access Journals (Sweden)

    Mariano García-Rodríguez

    2011-01-01

    Full Text Available The analysis of 255 bottom trawl samples obtained in annual experimental surveys (2007–2010 along the western Mediterranean shows the existence of five well-defined demersal assemblages that follow a depth distribution: (a upper shelf assemblages, including two assemblages differentiated by the type of substrate (sand-muddy and terrigenous muddy bottoms; (b a middle shelf assemblage; (c an upper slope assemblage; (d a middle slope assemblage. Faunally, they are dominated by fish (37% of 452 total species, followed by crustaceans (22%, molluscs (17%, echinoderms (9%, and other invertebrates (15%. The assemblages identified showed major alterations on the shelf and shelf edge and less pronounced ones on the upper and middle slope. The average diversity values were more or less high, evidencing the high species richness in the western Mediterranean. The identified assemblages may facilitate future multispecies fisheries management based on an ecosystem approach.

  8. Bioactive molecules from sea hares.

    Science.gov (United States)

    Kamiya, H; Sakai, R; Jimbo, M

    2006-01-01

    Sea hares, belonging to the order Opisthobranchia, subclass Gastropoda, are mollusks that have attracted many researchers who are interested in the chemical defense mechanisms of these soft and "shell-less" snails. Numbers of small molecules of dietary origin have been isolated from sea hares and some have ecologically relevant activities, such as fish deterrent activity or toxicity. Recently, however, greater attention has been paid to biomedically interesting sea hare isolates such as dolastatins, a series of antitumor peptide/macrolides isolated from Dolabella auricularia. Another series of bioactive peptide/macrolides, as represented by aplyronines, have been isolated from sea hares in Japanese waters. Although earlier studies indicated the potent antitumor activity of aplyronines, their clinical development has never been conducted because of the minute amount of compound available from the natural source. Recent synthetic studies, however, have made it possible to prepare these compounds and analogs for a structure-activity relationship study, and started to uncover their unique action mechanism towards their putative targets, microfilaments. Here, recent findings of small antitumor molecules isolated from Japanese sea hares are reviewed. Sea hares are also known to produce cytotoxic and antimicrobial proteins. In contrast to the small molecules of dietary origin, proteins are the genetic products of sea hares and they are likely to have some primary physiological functions in addition to ecological roles in the sea hare. Based on the biochemical properties and phylogenetic analysis of these proteins, we propose that they belong to one family of molecule, the "Aplysianin A family," although their molecular weights are apparently divided into two groups. Interestingly, the active principles in Aplysia species and Dolabella auricularia were shown to be L-amino acid oxidase (LAAO), a flavin enzyme that oxidizes an alpha-amino group of the substrate with

  9. Floating asphalt blocks of the Dead Sea

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A. (Weizmann Inst. of Science, Rehovot, Israel); Aizenshtat, Z.; Goldberg, M.

    1980-01-01

    Large blocks of mineral matter free (less than 0.1%) asphalt are occasionally found floating on the surface of the Dead Sea. Chemical, spectroscopic and isotopic data are given for the asphalt. The source of the asphalt is not accurately known, but presumably it represents mobilization of heavy viscous asphaltic masses at depth below the lake bottom into the floor of the lake. It may be released to the surface by earth tremors.

  10. Determination of Non-linear Damping Coefficients of bottom-hinged Oscillating Wave Surge Converters Using Numerical Free Decay Tests

    OpenAIRE

    Asmuth, Henrik; Schmitt, Pal; Henry, Alan; Elsaesser, Bjoern

    2014-01-01

    Linear wave theory models are commonly applied to predict the performance of bottom-hinged oscillating wave surge converters (OWSC) in operational sea states. To account for non-linear effects, the additional input of coefficients not included in the model itself becomes necessary. In ocean engineering it iscommon practice to obtain damping coefficients of floating structures from free decay tests. This paper presents results obtained from experimental tank tests and numerical computational f...

  11. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  12. An application of 8L4S176T observation system to seismic acquisition of ocean-bottom cable in CF block, Bohai Sea%8L4S176T观测系统在渤海CF区块海底电缆地震采集中的应用

    Institute of Scientific and Technical Information of China (English)

    龚旭东; 张建峰; 王志亮; 杨志国; 钮依莎

    2012-01-01

    In order to acquire excellent seismic data in the complex transitional zone of CF block, Bohai Sea, 8L4S176T observation system was applied, and several technical issues were appraised in detail, including acquisition equipment, source selection, cable laying, secondary positioning, etc. For the operation difficulties, such as low efficiency, big impact of tidal current, and many passing ships, during seismic acquisition, a series of technical measures were developed, including shooting along the survey lines, laying two more cables in advance, shooting at different time, increasing the cable weight, protecting cables with "an enclosure method" and other appropriate measures. The adoption of these measures has resulted in acquiring more information of wave field, improving effectively resolution of seismic data and increasing accuracy in imaging deep complex structures of the block.%为在渤海CF区块复杂过渡带获得高品质的地震采集资料,采用了8L4S176T观测系统,并在采集设备、震源选型、电缆铺设、二次定位等方面进行了详细论证;分析了采集作业过程中存在的施工效率低、潮流影响大、过往船只多等作业难点,提出了沿测线放炮、提前多铺设2根电缆、分时放炮、增加电缆配重、“圈地法”护缆等相应的技术措施,实施后取得了更丰富的波场信息,有效提高了地震资料分辨率,改善了该区块中深层复杂构造的成像精度.

  13. Developing an Algorithm for Finding Deep-Sea Corals on Seamounts Using Bathymetry and Photographic Data

    Science.gov (United States)

    Fernandez, D. P.; Adkins, J. F.; Scheirer, D. P.

    2006-12-01

    Over the last three years we have conducted several cruises on seamounts in the North Atlantic to sample and characterize the distribution of deep-sea corals in space and time. Using the deep submergence vehicle Alvin and the ROV Hercules we have spent over 80 hours on the seafloor. With the autonomous vehicle ABE and a towed camera sled, we collected over 10,000 bottom photographs and over 60 hours of micro- bathymetry over 120 km of seafloor. While there are very few living scleractinia (Desmophyllum dianthus, Solenosmilia sp. and, Lophilia sp.), we recovered over 5,000 fossil D. dianthus and over 60 kg of fossil Solenosmilia sp. The large numbers of fossil corals mean that a perceived lack of material does not have to limit the use of this new archive of the deep ocean. However, we need a better strategy for finding and returning samples to the lab. Corals clearly prefer to grow on steep slopes and at the tops of scarps of all scales. They are preferentially found along ridges and on small knolls flanking a larger edifice. There is also a clear preference for D. dianthus to recruit onto carbonate substrate. Overall, our sample collection, bathymetry and bottom photographs allow us to create an algorithm for finding corals based only on knowledge of the seafloor topography. We can test this algorithm against known sampling locations and visual surveys of the seafloor. Similar to the way seismic data are used to locate ideal coring locations, we propose that high-resolution bathymetry can be used to predict the most likely locations for finding fossil deep-sea corals.

  14. Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs.

    Directory of Open Access Journals (Sweden)

    Bernat Hereu

    Full Text Available We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80% on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present. Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management.

  15. Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs.

    Science.gov (United States)

    Hereu, Bernat; Linares, Cristina; Sala, Enric; Garrabou, Joaquim; Garcia-Rubies, Antoni; Diaz, David; Zabala, Mikel

    2012-01-01

    We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management. PMID:22606306

  16. NEW LANDSONAR METHOD FOR SURVEY OF GROUND IN BUSY TOWN, KARST CAVES IN MOUNTAIN AND SEA BOTTOM ON WATER%适合闹市区勘探及溶洞探查和水上勘探的物探新方法

    Institute of Scientific and Technical Information of China (English)

    钟世航; 王荣

    2013-01-01

    In busy city the geophysical exploration methods are interfered with the noise from vibration of heavy traffic and strong electromagnetic field and stray electricity.An conquering of the interference of rugged landform in mountain land also are the problem of all the geophysical method.Surveying of single karst cave with small or middle sizes is difficult.They are more required to put energy into the new development of technology and new method.Landsonar and its instrument can avoid the interference of noise from vibration of cars and pedestrains with frequency generally less than 300 Hz in city by exciting and receiving elastic waves of 10 ~4000 Hz.The instrument C-1can avoid the interference of strong electromagnetic field and stray electricity with supplying narrow frequency alternating current of 11 ~ 19 Hz.Because of the zero offset and high and wide frequency band,Landsonar can avoid the interference of landform and have high resolution on single karst cave with small to middle sizes.Because of the especial electrode arrangement,Differential Electric Sounding(DES) method can survey karst cave of 1 m high within 100m deep.KS marine acoustics prospecting instrument have better transverse and longitudinal resolution,can distinguish the silt layer,sand layer,cobble layer and riprap layer with thickness more than 1 m and geologic structure under sub-bottom,and can work with broken survey line and curve survey line.%城市闹市区的汽车、行人的震动噪声和地电及电磁干扰,使传统的物探方法难以为城铁、地铁作面积性的地质勘查.弹性波类方法必须克服噪声干扰,电法和电磁法类方则须避开地电和电磁干扰,才能在城市和公路上工作.探查中小溶洞是地质勘查的难题,也是传统物探技术的难题.崎岖山地的地形影响也是地球物理方法遇到的困难.这些都需要投入人力和资金发展新技术、新仪器.汽车、行人的震动噪声基本上在300Hz以下,陆地

  17. Clay as indicator of sediment plume movement in deep-sea environment

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    would screen the nodules just above the sea floor. The released sediments on the sea floor would migrate in the direction of the bottom water currents and affect the benthic community. It would be more hazardous when the sediment are discharged...

  18. Internal wave - zooplankton interactions in the Alboran Sea (W-Mediterranean)

    NARCIS (Netherlands)

    van Haren, H.

    2014-01-01

    An upward looking 75 kHz ADCP (Acoustic Doppler Current Profiler) was moored at 100 m above the bottom in 912 m water depth in the central-north Alboran Sea (W-Mediterranean Sea). The ADCP sampled current and acoustic echo-amplitude at a rate of once per minute for 9 days, thereby revealing particul

  19. Robust plasmonic substrates

    DEFF Research Database (Denmark)

    Kostiučenko, Oksana; Fiutowski, Jacek; Tamulevicius, Tomas;

    2014-01-01

    substrates is presented, which relies on the coverage of gold nanostructures with diamond-like carbon (DLC) thin films of thicknesses 25, 55 and 105 nm. DLC thin films were grown by direct hydrocarbon ion beam deposition. In order to find the optimum balance between optical and mechanical properties...... and breaking. DLC coating with thicknesses between 25 and 105 nm is found to considerably increase the mechanical strength of the substrates while at the same time ensuring conservation of sufficient field enhancements of the gold plasmonic substrates....

  20. Peach Bottom test element program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Saurwein, J.J.; Holzgraf, J.F.; MIller, C.M.; Myers, B.F.; Wallroth, C.F.

    1982-11-01

    Thirty-three test elements were irradiated in the Peach Bottom high-temperature gas-cooled reactor (HTGR) as part of the testing program for advanced HTGRs. Extensive postirradiation examinations and evaluations of 21 of these irradiation experiments were performed. The test element irradiations were simulated using HTGR design codes and data. Calculated fuel burnups, power profiles, fast neutron fluences, and temperatures were verified via destructive burnup measurements, gamma scanning, and in-pile thermocouple readings corrected for decalibration effects. Analytical techniques were developed to improve the quality of temperature predictions through feedback of nuclear measurements into thermal calculations. Dimensional measurements, pressure burst tests, diametral compression tests, ring-cutting tests, strip-cutting tests, and four-point bend tests were performed to measure residual stress, strain, and strength distributions in H-327 graphite structures irradiated in the test elements.

  1. Peach Bottom test element program. Final report

    International Nuclear Information System (INIS)

    Thirty-three test elements were irradiated in the Peach Bottom high-temperature gas-cooled reactor (HTGR) as part of the testing program for advanced HTGRs. Extensive postirradiation examinations and evaluations of 21 of these irradiation experiments were performed. The test element irradiations were simulated using HTGR design codes and data. Calculated fuel burnups, power profiles, fast neutron fluences, and temperatures were verified via destructive burnup measurements, gamma scanning, and in-pile thermocouple readings corrected for decalibration effects. Analytical techniques were developed to improve the quality of temperature predictions through feedback of nuclear measurements into thermal calculations. Dimensional measurements, pressure burst tests, diametral compression tests, ring-cutting tests, strip-cutting tests, and four-point bend tests were performed to measure residual stress, strain, and strength distributions in H-327 graphite structures irradiated in the test elements

  2. Designing the organisational chart from the bottom

    DEFF Research Database (Denmark)

    Giangreco, Antonio; Carugati, Andrea

    This is the first of a two-case series (408-026-1 and 408-027-1). Marco Ginola was hired as the Human Resources (HR) Director of a large municipality in central Italy. The organisation had gone through a phase of major expansion which left problems in co-ordination, integration, delegation...... and control. Marco had been called in because of his reputation for being an effective innovator with unconventional ideas for the public sector. Previously, during his long career in the civil service, Marco proved to be an effective leader and negotiator who was open to other people's view points. He would...... share any significant and final decisions with his employees, rather than merely imposing his own personal choice. After spending some time in the organisation, he put into action a bottom up method to redesign the structure of the HR department. He decided to temporarily suspend the existing internal...

  3. BC Hydro triple bottom line report 2002

    International Nuclear Information System (INIS)

    British Columbia Hydro (BC Hydro) published this document which measures the environmental, social and economic performance of the company. It is a complement to BC Hydro's 2002 Annual Report. The report was prepared to better understand the company's business in terms of its commitment to being an environmentally, socially, and economically responsible company (the three bottom lines). BC Hydro proved its ability to integrate the three bottom lines in decision making processes by carefully examining the environmental, social and economical impacts of programs such as Power Smart, Green and Alternative Energy, and Water Use Planning. All indicators point to BC Hydro achieving its commitment of providing a minimum of 10 per cent of new demand through 2010 with new green energy sources. Water Use Plans were developed for hydroelectric generating stations, and they should all be in place by 2003. Efficiencies realised through the Power Smart program offset the increases in greenhouse gas associated with increased energy demand. Juvenile sturgeon raised in a hatchery were released into the Columbia River in May 2002. The completion of a 40-kilometre trail on the Sunshine Coast was helped by a financial contribution from BC Hydro in the amount of 23,000 dollars. Safety improvements were implemented at eight facilities, such as dam remediation, dam surveillance and instrumentation updates. Scholarships were awarded across the province, along with additional donations to non-profit organizations. Co-op positions were provided for 150 students. Internal energy efficiency programs were successful. Planning is under way for significant maintenance work and equipment replacement projects as the transmission and distribution infrastructure ages. The number of reported indicators was expanded this year. In turn, they were aligned with the revised Global Reporting Initiative (GRI) guidelines. tabs

  4. Investigation of Top/Bottom electrode and Diffusion Barrier Layer for PZT Thick Film MEMS Sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Thomsen, Erik Vilain

    2008-01-01

    Top and bottom electrodes for screen printed piezoelectric lead zirconate titanate, Pb(ZrxTi1 - x)O3 (PZT) thick film are investigated with respect to future MEMS devices. Down to 100 nm thick E-beam evaporated Al and Pt films are patterned as top electrodes on the PZT using a lift-off process wi...... with a line width down to 3 μ m. A 700 nm thick ZrO2 layer as insolating diffusion barrier layer is found to be insufficient as barrier layer for PZT on a silicon substrate sintered at 850°C. EDX shows diffusion of Si into the PZT layer....

  5. Variability of subsurface denitrification and surface productivity in the coastal eastern Arabian Sea over the past seven centuries

    Digital Repository Service at National Institute of Oceanography (India)

    Agnihotri, R.; Kurian, S.; Fernandes, M.; Reshma, K.; DeSouza, W.; Naqvi, S.W.A

    Temporal variations over the last approx. 700 years in surface productivity and subsurface denitrification in the coastal eastern Arabian Sea (off Goa, India), a hydrographically unique environment that experiences seasonal near-bottom anoxia, have...

  6. NPRB711 Quantification of unobserved injury and mortality of Bering Sea crabs due to encounters with trawls on the seafloor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The potential for unobserved mortality of crabs encountering bottom trawls, but not captured, has long been a concern in the management of Bering Sea fisheries. We...

  7. 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.

  8. Characteristics of the Japanese sea cucumber Apostichopus japonicus's population in the Sea of Japan (Kievka Bay)

    Science.gov (United States)

    Gavrilova, G. S.; Sukhin, I. Yu.

    2011-06-01

    In Kievka Bay of the Sea of Japan, the population of the Japanese sea cucumber Apostichopus japonicus inhabits the areas of coarse sediments and complex bottom topography. These distributional patterns are closely related to the species' ecology, i.e., to the demand for protection against the wave turbulence. The aggregationing coverage of the sea cucumber population is about 80 hectares, where ˜200 thousand animals were accounted for in the last years. The aggregation's area varies during the year, which is closely related to the species' biological peculiarities, such as their behavioral patterns and the redistribution of their food resources. A significant increase of the juvenile population occurred after the farm-reared sea cucumber spat were released in 2003.

  9. Changes in sea-ice cover and temperature in the Western Ross Sea during the Holocene

    Science.gov (United States)

    Fleury, Sophie; Kim, Jung-Hyun; Gal, Jong-Ku; Mezgec, Karin; Belt, Simon; Smik, Lukas; Stenni, Barbara; Melis, Romana; Crosta, Xavier; Shin, Kyung-Hoon

    2016-04-01

    Although changes in sea-ice cover contribute to global climatic variations, they are poorly constrained for periods earlier than the last decades. More records are especially required around Antarctica, where the formation of Antarctic Bottom Waters participates to global thermohaline circulation. However, this region provided only a few marine sediment cores spanning the entire Holocene, especially because of generally low sedimentation rates. This study focuses on marine sediment core ANTA99-CJ5 (73°49'S; 175°39'E), located in the open sea ice zone (OSIZ) of the western Ross Sea. We analyzed several lipid biomarkers: highly branched isoprenoids (HBIs), sterols, diols and GDGTs. The combination of several biomarkers and the comparison of these results with a diatom record previously published on the same core enabled us to trace past changes in temperatures as well as in sea-ice condition over the last 11,600 years.

  10. Geomorphologic characteristics and origin of the valley bottom troughs at the site of Three Gorges Dam

    Institute of Scientific and Technical Information of China (English)

    LIXusheng; YANGDayuang; KEXiankun; ZHOULufu; CHENDeji

    2003-01-01

    This paper describes valley bottom troughs of the Changjiang River and infers the geomorphologic development of troughs. Based on the morphology of the troughs, the following conclusions are drawn. (1) The deep troughs on the Three Gorges valley bottom are formed by river downcutting along the structural zones on the background of regional tectonic uplift at about 40-30 ka BP. (2) When river downcutting occurred in the river bed of Changjiang, the jets current (particularly eddy current) with a large number of pebbles ground and eroded the valley bottom, resulting in trough formation and deepening. Meanwhile, water currents with gravels and pebbles eroded the bank and the left wall of No.76 trough as well as the right wall of No.77 trough by striking, scouring, horizontal and vertical grinding. (3) The depth of the trough is mainly determined by the intensity of the water current and the consistency of bedrock against erosion, and is not controlled hv the altihlde of the sea level as the base level of erosion.

  11. Influence of bottom topography roughness on the jet and inertial recirculation of a mid-latitude gyre

    Science.gov (United States)

    Barnier, Bernard; Le Provost, Christian

    1993-06-01

    Several numerical experiments are conducted to examine the influence of mesoscale, bottom topography roughness on the inertial circulation of a wind-driven, mid-latitude ocean gyre. The ocean model is based on the quasi-geostrophic formulation, and is eddy-resolving as it features high vertical and horizontal resolutions (six layers and a 10 km grid). An antisymmetrical double-gyre wind stress curl forces the baroclinic modes and generates a strong surface jet. In the case of a flat bottom, inertia and inverse energy cascade force the barotropic mode, and the resulting circulation features strong, barotropic, inertial gyres. The sea-floor roughness inhibits the inertial circulation in the deep layers; the barotropic component of the flow is then forced by eddy-topography interactions, and its energy concentrates at the scales of the topography. As a result, the baroclinicity of the flow is intesified: the barotropic mode is reduced with regard to the baroclinic modes, and the bottom flow (constrained by the mesoscale sea-floor roughness) is decoupled from the surface flow (forced by the gyre-scale wind). Rectified, mesoscale bottom circulation induces an interfacial form stress at the thermocline, which enhances horizontal shear instability and opposes the eastward penetration of the jet. The mean jet is consequently shortened, but the instantaneous jet remains very turbulent, with meanders of large meridional extent. The sea-floor roughness modifies the energy pathways, and the eddies have an even more important role in the establishment of the mean circulation: below the thermocline, rectification processes are dominant, and eddies transfer energy toward permanent mesoscale circulations strongly correlated with topography, whereas above the thermocline mean flow and eddy generation are influenced by the mean bottom circulation through interfacial stress. The topography modifies the vorticity of the barotropic and highest baroclinic modes. Vorticity accumulates at

  12. Pressure drop evaluation in fuel assembly bottom nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Sydney da Silva; Brittes, Luiz Henrique A. [Industrias Nucleares do Brasil S.A. (INB), Resende, RJ (Brazil)]. E-mails: sydney@inb.gov.br; brittes@inb.gov.br; Navarro, Moyses A. [Centro de Desenvolvimento de Energia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: navarro@cdtn.br

    2007-07-01

    Experiments were conducted in order to assess the pressure drop through an anti-debris bottom nozzle relatively to a standard bottom nozzle of a nuclear fuel assembly. Two kinds of experiments have been performed: one using bottom nozzles connected with the lower part of a Fuel Assembly (containing two spacer grids) and another one using the bottom nozzle alone. Reynolds numbers ranging from 10500 . 95000 have been employed, temperatures ranging from 40 . 55 deg C and pressures up to 4 bar. Results have shown that the pressure drop coefficients of the anti-debris nozzle referring to the whole lower region of the Fuel Assembly were {approx} 13% (for Re {approx_equal} 95000) till {approx} 17% (for Re {approx_equal} 10500) higher than the coefficients for standard bottom nozzle. This difference increases up to 118% when the pressure drop coefficients of the bottom nozzle alone are considered. (author)

  13. Transient Temperature Analysis for Industrial AC Arc Furnace Bottom

    Institute of Scientific and Technical Information of China (English)

    (U)nal (C)amdal1; Murat Tun(c)

    2004-01-01

    Heat losses from the furnaces depend on the design and size. The surface heat loss from the bottom of an industrial AC electric arc furnace (EAF) possesses an important fraction of overall losses. So in this study the transient temperature variation at the bottom of the EAF was investigated. The transient temperature analysis was carried out using MATLAB computer program. T=T(r, t) for different bottom lining layers was depicted.

  14. Coupling of ocean bottom seismometers to sediment: results of tests with the U.S. Geological Survey ocean bottom seismometer

    Science.gov (United States)

    Trehu, Anne M.

    1985-01-01

    The response of an ocean bottom seismometer (OBS) to a transient pull that excites the natural OBS-sediment coupling resonance can be modeled as a mass-spring-dashpot system in which the resonant frequency and damping are functions of instrument mass and bearing radius and of the physical properties of the sediment (primarily the shear modulus). For the very soft sediments sometimes found on the sea floor, this resonance may be within the main frequency band of interest (2 to 15 Hz) for many common instrument configurations. To test the model and to find an anchor that would shift the coupling resonance to a higher frequency and decrease its amplitude, we conducted a series of tests which measured the response of the vertical and horizontal components of the U.S. Geological Survey OBS to transient pulls as a function of anchor configuration and sediment properties. The tested anchors included a concrete “flowerpot,” a tripod, a plate, and a perforated plate. Sites were on soft, organic-rich ooze and on firm sand. Several small shots were also fired at the ooze site in order to compare the response of the plate and “flowerpot” anchors to seismic signals. For a given anchor at a given site, the observed response was very repeatable. We found that the model predicts the vertical coupling response quite well and that good vertical coupling can be achieved with the plate or perforated-plate anchors. The response to the horizontal pulls, however, was similar and resonant for all anchors.

  15. Method of coupled mode for long-range bottom reverberation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The theory of coupled mode is used for modeling the long-range bottom reverberation in shallow water caused by bottom roughness. The distant bottom reverberation level and spatial coherence of impulsive source are both derived. The results agree with those from the classical reverberation model, and are compared with the experimental data. The influence of source bandwidth and the distance between sources and receivers on the intensity of bottom reverberation are particularly discussed. The method is shown to be available for both the monoand the bi-static cases.

  16. Bottom water oxygenation changes in the northern Okinawa Trough since the last 88ka: Controlled by local hydrology and climate

    Science.gov (United States)

    Zou, Jianjun; Shi, Xuefa; Zhu, Aimei; Bai, Yazhi; Selvaraj, Kandasamy

    2014-05-01

    Dissolved oxygen content in oceanic bottom water is closely related to the surface organic carbon export and subsurface water stratification, regulating the biogeochemical cycles of some key nutrients and trace elements in intermediate and deep water columns. Further, the rate of organic carbon flux to sediments and bottom water oxygen concentration together determine the intensity of reducing conditions in sediments. In this study, we obtain high-resolution geochemical elements (TOC, TN, TS, CaCO3, Cd, U, Mn and Mo) in a radiocarbon (14C) and δ18O dated, sediment core CSH1 collected from the northern Okinawa Trough to reconstruct the history of bottom water redox conditions over 88 ka. Our data revealed the presence of hypoxic bottom water in the northern Okinawa Trough during late MIS5a-early MIS4, Last Glacial Maximum, and the early Last Deglacial intervals. During the Holocene and the early MIS5a, the dissolved oxygen content in bottom water has increased with decreasing water stratification, which was probably caused by the increased upwelling from the bottom in tandem with the climbing of Kuroshio Current and subdued freshwater effect in the northern Okinawa Trough. The reasons that caused the change of dissolved oxygen content in bottom water in the northern Okinawa Trough varied during different periods. The main factors are related to sea level, strengths of East Asian monsoon and the Kuroshio Current, and the shift of Westerly Jet Axis. The semi-closed topography in the northern Okinawa Trough provides a space framework for the presence of anoxia, while the sea level together with the Kuroshio Current, the East Asian monsoon and the Westerly Jet Axis seems to affect the strength of water stratification and the nutrient supply; thereby, regulating the dissolved oxygen exchange between surface and bottom waters. This work was supported by the National Natural Science Foundation of China(Grant No.:40906035,40710069004) and by basic scientific fund for

  17. Suspension freezing of bottom sediment and biota in the Northwest Passage and implications for Arctic Ocean sedimentation

    Science.gov (United States)

    Reimnitz, E.; Marincovich, L.; McCormick, M.; Briggs, W.M.

    1992-01-01

    No evidence was seen for entrainment by bottom adfreezing, bluff slumping, river flooding, dragging ice keels, or significant eolian transport from land to sea. Muddy sediment with pebbles and cobbles, algae with holdfasts, ostracodes with appendages, and well-preserved mollusks and sea urchins were collected from two sites in a 50 km long stretch of turbid ice. These materials indicate that suspension freezing reaching to a water depth of 25-30 m during the previous fall was responsible for entrainment. This mechanism requires rapid ice formation in open, shallow water during a freezing storm, when the ocean becomes supercooled, and frazil and anchor ice attach to and ultimately lift sediment and living organisms to the sea surface. -from Authors

  18. How Service Innovation Boosts Bottom Lines

    Directory of Open Access Journals (Sweden)

    Claude Legrand

    2013-09-01

    Full Text Available In the national quest for ground-breaking R&D discoveries and inventions, service innovation is frequently ignored at considerable cost to an organization’s bottom line and a nation’s productivity. For the fact is that innovation applied systematically to all activities outside of R&D can make the difference between uninspiring results and substantial growth in every sector. Many countries, in particular in Europe, have recognized the importance of service innovation and are devoting considerable resources to research, the capture of best practices, and the measurement of progress and success. Given the physiognomy of the modern economy, it does not make sense for leaders in the Canadian public sector to devote all available innovation investment dollars to science and technology R&D. This article explores why service innovation is not yet a priority on the innovation agenda in Canada and why we should correct the dangerous misconception that there is just one “innovation gap” that needs to be addressed. It provides practical recommendations that public and private sector leaders can use to take advantage of this under-valued, high-potential innovation opportunity and calls for the creation of a national service innovation resource to support enterprises of all sizes as a means to improve Canadian productivity.

  19. To the Bottom of the Sbottom

    CERN Document Server

    Han, Tao; Wu, Yongcheng; Zhang, Bin; Zhang, Huanian

    2015-01-01

    In the search for bottom squark (sbottom) in SUSY at the LHC, the common practice has been to assume a $100\\%$ decay branching fraction for a given search channel. In realistic MSSM scenarios, there are often more than one significant decay modes to be present, which significantly weaken the current sbottom search limits at the LHC. On the other hand, the combination of the multiple decay modes offers alternative discovery channels for sbottom searches. In this paper, we present the sbottom decays in a few representative mass parameter scenarios. We then analyze the sbottom signal for the pair production in QCD with one sbottom decaying via $\\tilde{b}\\rightarrow b \\chi_1^0,\\ b \\chi_2^0$, and the other one decaying via $\\tilde{b} \\rightarrow t \\chi_1^\\pm$. With the gaugino subsequent decaying to gauge bosons or a Higgs boson $\\chi_2^0 \\rightarrow Z \\chi_1^0,\\ h \\chi_1^0$ and $\\chi_1^\\pm \\rightarrow W^\\pm \\chi_1^0$, we study the reach of those signals at the 14 TeV LHC with 300 ${\\rm fb^{-1}}$ integrated lumino...

  20. Ocean Bottom Seismometer: Design and Test of a Measurement System for Marine Seismology

    Directory of Open Access Journals (Sweden)

    Javier Cadena

    2012-03-01

    Full Text Available The Ocean Bottom Seismometer (OBS is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal–to-Noise Ratio (SNR based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth’s crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

  1. Temperature impacts on deep-sea biodiversity.

    Science.gov (United States)

    Yasuhara, Moriaki; Danovaro, Roberto

    2016-05-01

    Temperature is considered to be a fundamental factor controlling biodiversity in marine ecosystems, but precisely what role temperature plays in modulating diversity is still not clear. The deep ocean, lacking light and in situ photosynthetic primary production, is an ideal model system to test the effects of temperature changes on biodiversity. Here we synthesize current knowledge on temperature-diversity relationships in the deep sea. Our results from both present and past deep-sea assemblages suggest that, when a wide range of deep-sea bottom-water temperatures is considered, a unimodal relationship exists between temperature and diversity (that may be right skewed). It is possible that temperature is important only when at relatively high and low levels but does not play a major role in the intermediate temperature range. Possible mechanisms explaining the temperature-biodiversity relationship include the physiological-tolerance hypothesis, the metabolic hypothesis, island biogeography theory, or some combination of these. The possible unimodal relationship discussed here may allow us to identify tipping points at which on-going global change and deep-water warming may increase or decrease deep-sea biodiversity. Predicted changes in deep-sea temperatures due to human-induced climate change may have more adverse consequences than expected considering the sensitivity of deep-sea ecosystems to temperature changes. PMID:25523624

  2. Temperature Impacts on Deep-Sea Biodiversity

    Science.gov (United States)

    Yasuhara, M.; Danovaro, R.

    2015-12-01

    Temperature is considered to be a fundamental factor controlling biodiversity in marine ecosystems, but precisely what role temperature plays in modulating diversity is still not clear. The deep ocean, lacking light and in situ photosynthetic primary production, is an ideal model system to test the effects of temperature changes on biodiversity. Here we synthesize current knowledge on temperature-diversity relationships in the deep sea. Our results from both present and past deep-sea assemblages suggest that, when a wide range of deep-sea bottom-water temperatures is considered, a unimodal relationship exists between temperature and diversity (that may be right skewed). It is possible that temperature is important only when at relatively high and low levels but does not play a major role in the intermediate temperature range. Possible mechanisms explaining the temperature-biodiversity relationship include the physiological-tolerance hypothesis, the metabolic hypothesis, island biogeography theory, or some combination of these. The possible unimodal relationship discussed here may allow us to identify tipping points at which on-going global change and deep-water warming may increase or decrease deep-sea biodiversity. Predicted changes in deep-sea temperatures due to human-induced climate change may have more adverse consequences than expected considering the sensitivity of deep-sea ecosystems to temperature changes.

  3. Biaxially textured composite substrates

    Energy Technology Data Exchange (ETDEWEB)

    Groves, James R.; Foltyn, Stephen R.; Arendt, Paul N.

    2005-04-26

    An article including a substrate, a layer of a metal phosphate material such as an aluminum phosphate material upon the surface of the substrate, and a layer of an oriented cubic oxide material having a rock-salt-like structure upon the metal phosphate material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon a layer of a buffer material such as a SrTi.sub.x Ru.sub.1-x O.sub.3 layer.

  4. Echoes from the past: a healthy Baltic Sea requires more effort.

    Science.gov (United States)

    Kotilainen, Aarno T; Arppe, Laura; Dobosz, Slawomir; Jansen, Eystein; Kabel, Karoline; Karhu, Juha; Kotilainen, Mia M; Kuijpers, Antoon; Lougheed, Bryan C; Meier, H E Markus; Moros, Matthias; Neumann, Thomas; Porsche, Christian; Poulsen, Niels; Rasmussen, Peter; Ribeiro, Sofia; Risebrobakken, Bjørg; Ryabchuk, Daria; Schimanke, Semjon; Snowball, Ian; Spiridonov, Mikhail; Virtasalo, Joonas J; Weckström, Kaarina; Witkowski, Andrzej; Zhamoida, Vladimir

    2014-02-01

    Integrated sediment multiproxy studies and modeling were used to reconstruct past changes in the Baltic Sea ecosystem. Results of natural changes over the past 6000 years in the Baltic Sea ecosystem suggest that forecasted climate warming might enhance environmental problems of the Baltic Sea. Integrated modeling and sediment proxy studies reveal increased sea surface temperatures and expanded seafloor anoxia (in deep basins) during earlier natural warm climate phases, such as the Medieval Climate Anomaly. Under future IPCC scenarios of global warming, there is likely no improvement of bottom water conditions in the Baltic Sea. Thus, the measures already designed to produce a healthier Baltic Sea are insufficient in the long term. The interactions between climate change and anthropogenic impacts on the Baltic Sea should be considered in management, implementation of policy strategies in the Baltic Sea environmental issues, and adaptation to future climate change. PMID:24414805

  5. Light Quark Mass Effects in Bottom Quark Mass Determinations

    OpenAIRE

    Hoang, A. H.

    2001-01-01

    Recent results for charm quark mass effects in perturbative bottom quark mass determinations from $\\Upsilon$ mesons are reviewed. The connection between the behavior of light quark mass corrections and the infrared sensitivity of some bottom quark mass definitions is examined in some detail.

  6. Bottom-up Attention Orienting in Young Children with Autism

    Science.gov (United States)

    Amso, Dima; Haas, Sara; Tenenbaum, Elena; Markant, Julie; Sheinkopf, Stephen J.

    2014-01-01

    We examined the impact of simultaneous bottom-up visual influences and meaningful social stimuli on attention orienting in young children with autism spectrum disorders (ASDs). Relative to typically-developing age and sex matched participants, children with ASDs were more influenced by bottom-up visual scene information regardless of whether…

  7. Epifauna dynamics at an offshore foundation--implications of future wind power farming in the North Sea.

    Science.gov (United States)

    Krone, Roland; Gutow, Lars; Joschko, Tanja J; Schröder, Alexander

    2013-04-01

    In the light of the introduction of thousands of large offshore wind power foundations into the North Sea within the next decades, this manuscript focuses on the biofouling processes and likely reef effects. The study explores the macrozoobenthos (biofouling) colonization at an offshore platform which is comparable to offshore wind turbine foundations. A total of 183 single samples were taken and the parameters water depth and time were considered comparing biofouling masses and communities. The blue mussel Mytilus edulis, Anthozoa and the Amphipoda Jassa spp. were the dominant species. The community from the 1 m zone and those from the 5 and 20-28 m zones can clearly be differentiated. The 10 m zone community represents the transition between the M. edulis dominated 1 m and 5 m zones and the Anthozoa dominated 20-28 m zone. In the future offshore wind farms, thousands of wind turbine foundations will provide habitat for a hard bottom fauna which is otherwise restricted to the sparse rocky habitats scattered within extensive sedimentary soft bottoms of the German Bight. However, offshore wind power foundations cannot be considered natural rock equivalents as they selectively increase certain natural hard bottom species. The surface of the construction (1280 m²) was covered by an average of 4300 kg biomass. This foundation concentrates on its footprint area (1024 m²) 35 times more macrozoobenthos biomass than the same area of soft bottom in the German exclusive economic zone (0.12 kg m(-2)), functioning as a biomass hotspot. Concerning the temporal biomass variation, we assume that at least 2700 kg biomass was exported on a yearly basis. 345 × 10(4) single mussel shells of different sizes were produced during the study period. It is anticipated that the M. edulis abundance will increase in the North Sea due to the expansion of the offshore wind farm development. This will result in the enhanced production of secondary hard substrate (mussel shells

  8. Pretreatment and utilization of waste incineration bottom ashes

    DEFF Research Database (Denmark)

    Astrup, Thomas

    2007-01-01

    Within recent years, researchers and authorities have had increasing focus on leaching properties from waste incineration bottom ashes. Researchers have investigated processes such as those related to carbonation, weathering, metal complexation, and leaching control. Most of these investigations......, however, have had a strong emphasis on lab experiments with little focus on full scale bottom ash upgrading methods. The introduction of regulatory limit values restricting leaching from utilized bottom ashes, has created a need for a better understanding of how lab scale experiences can be utilized...... in full scale bottom ash upgrading facilities, and the possibilities for complying with the regulatory limit values. A range of Danish research and development projects have within 1997-2005 investigated important techniques for bottom ash upgrading. The primary focus has been placed on curing...

  9. EFFECTS OF VARYING BOTTOM ON NONLINEAR SURFACE WAVES

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The resonant flow of an incompressible, inviscid fluid with surface tension on varying bottoms was researched. The effects of different bottoms on the nonlinear surface waves were analyzed. The waterfall plots of the wave were drawn with Matlab according to the numerical simulation of the fKdV equation with the pseudo-spectral method. From the waterfall plots, the results are obtained as follows: for the convex bottom, the waves system can be viewed as a combination of the effects of forward-step forcing and backward step forcing, and these two wave systems respectively radiate upstream and downstream without mutual interaction. Nevertheless, the result for the concave bottom is contrary to the convex one. For some combined bottoms, the wave systems can be considered as the combination of positive forcing and negative forcing.

  10. Multiple alternative substrate kinetics.

    Science.gov (United States)

    Anderson, Vernon E

    2015-11-01

    The specificity of enzymes for their respective substrates has been a focal point of enzyme kinetics since the initial characterization of metabolic chemistry. Various processes to quantify an enzyme's specificity using kinetics have been utilized over the decades. Fersht's definition of the ratio kcat/Km for two different substrates as the "specificity constant" (ref [7]), based on the premise that the important specificity existed when the substrates were competing in the same reaction, has become a consensus standard for enzymes obeying Michaelis-Menten kinetics. The expansion of the theory for the determination of the relative specificity constants for a very large number of competing substrates, e.g. those present in a combinatorial library, in a single reaction mixture has been developed in this contribution. The ratio of kcat/Km for isotopologs has also become a standard in mechanistic enzymology where kinetic isotope effects have been measured by the development of internal competition experiments with extreme precision. This contribution extends the theory of kinetic isotope effects to internal competition between three isotopologs present at non-tracer concentrations in the same reaction mix. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment.

  11. Impact of accelerated future global mean sea level rise on hypoxia in the Baltic Sea

    Science.gov (United States)

    Meier, H. E. M.; Höglund, A.; Eilola, K.; Almroth-Rosell, E.

    2016-08-01

    Expanding hypoxia is today a major threat for many coastal seas around the world and disentangling its drivers is a large challenge for interdisciplinary research. Using a coupled physical-biogeochemical model we estimate the impact of past and accelerated future global mean sea level rise (GSLR) upon water exchange and oxygen conditions in a semi-enclosed, shallow sea. As a study site, the Baltic Sea was chosen that suffers today from eutrophication and from dead bottom zones due to (1) excessive nutrient loads from land, (2) limited water exchange with the world ocean and (3) perhaps other drivers like global warming. We show from model simulations for the period 1850-2008 that the impacts of past GSLR on the marine ecosystem were relatively small. If we assume for the end of the twenty-first century a GSLR of +0.5 m relative to today's mean sea level, the impact on the marine ecosystem may still be small. Such a GSLR corresponds approximately to the projected ensemble-mean value reported by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. However, we conclude that GSLR should be considered in future high-end projections (>+1 m) for the Baltic Sea and other coastal seas with similar hydrographical conditions as in the Baltic because GSLR may lead to reinforced saltwater inflows causing higher salinity and increased vertical stratification compared to present-day conditions. Contrary to intuition, reinforced ventilation of the deep water does not lead to overall improved oxygen conditions but causes instead expanded dead bottom areas accompanied with increased internal phosphorus loads from the sediments and increased risk for cyanobacteria blooms.

  12. Final summary report on the Peach Bottom End-of-Life Program

    International Nuclear Information System (INIS)

    HTGR design methods verifications have been performed under the Peach Bottom End-of-Life Program by comparison of actual with predicted physics, thermal, fission product, and materials behavior in Peach Bottom. These design methods verifications have utilized the data determined from nondestructive fuel and circuit gamma scanning on-site, from laboratory examinations of samples removed from the primary circuit, and from a complementary program of Peach Bottom fuel element postirradiation examinations at Oak Ridge National Laboratory. Fifty-five driver fuel elements were axially gamma scanned to determine fission product distributions for use in burnup calculations, power profile determinations, and fission product release and redistribution studies. The cesium plateout distribution in the primary circuit was subsequently mapped by gamma scanning the ducting at 12 locations, axially traversing 79 steam generator tubes with Cd Te detectors from the water side, and internally scanning two vertical runs of ducting. Component removal involved trepanning of the primary circuit ducting, obtaining access to the steam generator internals, and removing over 100 superheater, evaporator, and economizer tubing samples. During this phase, macroscopic examinations of the steam generator and ducting internals were performed. Subsequent laboratory examinations of removed samples included radiochemical tests to substantiate in-situ gamma scans and to determine 90Sr distributions; metallurgical tests to evaluate surface films, microstructural changes, and residual mechanical properties; and tritium permeation tests to provide data for improving HTGR tritium release predictions. The condition and metallurgical integrity of all components examined were found to be excellent, with minimal coolant/substrate interaction and entirely acceptable residual mechanical properties. The suitability of the materials used in the construction of the Peach Bottom HTGR was thereby confirmed

  13. Organic matter recycling during a mucilage event and its influence on the surrounding environment (Ligurian Sea, NW Mediterranean)

    Science.gov (United States)

    Misic, Cristina; Schiaparelli, Stefano; Harriague, Anabella Covazzi

    2011-04-01

    The development of benthic mucilage in the Marine Protected Area of Portofino (Ligurian Sea) during the summer of 2009 was studied to verify the influence of this event on the surrounding environment (seawater and soft-bottom). The calm meteorological and sea conditions at the beginning of the time frame under consideration caused the thermal stratification of the water column. This stratification was one of the driving factors influencing the development of the mucilage, which developed on a large boulder surface above the pycnocline. Mucilage was progressively detached from the boulder surface by hydrodynamism, together with macroalgae, and sank onto the sediment below the thermocline. Increased surface-water movements, caused by meteorological forcing during the study period, influenced the aggregation-disaggregation of mucilage flocks above the thermocline, leading to increased dissolved oxygen concentrations and enhanced production and turnover of the organic matter (OM). Mixing with the adjacent seawater led to the fertilisation of the surrounding environment with potentially labile OM and inorganic phosphorus, which caused increases in the hydrolytic enzymatic activity. Conversely, below the thermocline, the sunken mucilage and algae aggregates supported a heterotrophic consumption system. Dissolved oxygen concentrations were lower than those recorded in the mucilage lying above the thermocline, making more carbohydrates than proteins and labile phosphorus available. Despite the slow oxygenation of this mucilage, it contributed to the food supply for the soft-bottom macrofauna, which showed an increase in density, diversity and biomass during the study. These results suggest that the development and fate of the mucilage, as well as its interactions with the surrounding environment, were principally regulated by physical features. In the oligotrophic coastal area of the Ligurian Sea, certain compartments of the ecosystem were able to promptly respond and take

  14. Sensitivity of sea ice and ocean simulations to sea ice salinity in a coupled global climate model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The impacts of the spatiotemporal variations of sea ice salinity on sea ice and ocean characteristics have not been studied in detail, as the existing climate models neglect or misrepresent this process. To address this issue, this paper formulated a parameterization with more realistic sea ice salinity budget, and examined the sensitivity of sea ice and ocean simulations to the ice salinity variations and associated salt flux into the ocean using a coupled global climate model. Results show that the inclusion of such a parameterization leads to an increase and thickening of sea ice in the Eurasian Arctic and within the ice pack in the Antarctic circumpolar region, and a weakening of the North Atlantic Deep Water and a strengthening of the Antarctic Bottom Water. The atmospheric responses associated with the ice changes were also discussed.

  15. Mammals of the Sea.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  16. Map of Distribution of Bottom Sediments on the Continental Shelf, Gulf of Alaska

    Science.gov (United States)

    Evans, Kevin R.; Carlson, Paul R.; Hampton, Monty A.; Marlow, Michael S.; Barnes, Peter W.

    2000-01-01

    Introduction The U.S. Geological Survey has a long history of exploring marine geology in the Gulf of Alaska. As part of a cooperative program with other federal and state agencies, the USGS is investigating the relations between ocean-floor geology and benthic marine biohabitats. This bottom sediment map, compiled from published literature will help marine biologists develop an understanding of sea-floor geology in relation to various biological habitats. The pattern of sea-floor sedimentation and bottom morphology in the Gulf of Alaska reflects a complex interplay of regional tectonism, glacial advances and retreats, oceanic and tidal currents, waves, storms, eustatic change, and gravity-driven processes. This map, based on numerous cruises during the period of 1970-1996, shows distribution of bottom sediments in areas of study on the continental shelf. The samples were collected with piston, box, and gravity corers, and grab samplers. The interpretations of sediment distribution are the products of sediment size analyses combined with interpretations of high-resolution seismic reflection profiles. The sea floor was separated into several areas as follows: Cook Inlet -- Hazards studies in this embayment emphasized sediment distribution, sediment dynamics, bedforms, shallow faults, and seafloor stability. Migrating mega-sandwaves, driven by strong tidal currents, influence seabed habitats and stability of the seafloor, especially near pipelines and drilling platforms. The coarseness of the bottom sediment reinforces the influence of the strong tidal currents on the seafloor habitats. Kodiak Shelf -- Tectonic framework studies demonstrate the development of an accretionary wedge as the Pacific Plate underthrusts the Alaskan landmass. Seismic data across the accretionary wedge reveal anomalies indicative of fluid/gas vent sites in this segment of the continental margin. Geologic hazards research shows that movement along numerous shallow faults poses a risk to sea

  17. A Preliminary Study of the Gas Hydrate Stability Zone in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    金春爽; 汪集旸

    2002-01-01

    Based on the analysis of sea-bottom temperature and geothermal gradient, and by means of the phaseboundary curve of gas hydrate and the sea-bottom temperature versus water depth curve in the South China Sea, thispaper studies the temperature and pressure conditions for gas hydrate to keep stable. In a marine environment, methanehydrate keeps stable at water depths greater than 550 m in the South China Sea. Further, the thickness of the gas hydratestability zone in the South China Sea was calculated by using the phase boundary curve and temperature-depth equations.The result shows that gas hydrate have a better perspective in the southeast of the Dongsha Islands, the northeast of theXisha Islands and the north of the Nansha Islands for thicker stability zones.

  18. Top Down Chemistry Versus Bottom up Chemistry

    Science.gov (United States)

    Oka, Takeshi; Witt, Adolf N.

    2016-06-01

    The idea of interstellar top down chemistry (TDC), in which molecules are produced from decomposition of larger molecules and dust in contrast to ordinary bottom up chemistry (BUC) in which molecules are produced synthetically from smaller molecules and atoms in the ISM, has been proposed in the chemistry of PAH and carbon chain molecules both for diffusea,c and dense cloudsb,d. A simple and natural idea, it must have occurred to many people and has been in the air for sometime. The validity of this hypothesis is apparent for diffuse clouds in view of the observed low abundance of small molecules and its rapid decrease with molecular size on the one hand and the high column densities of large carbon molecules demonstrated by the many intense diffuse interstellar bands (DIBs) on the other. Recent identification of C60^+ as the carrier of 5 near infrared DIBs with a high column density of 2×1013 cm-2 by Maier and others confirms the TDC. This means that the large molecules and dust produced in the high density high temperature environment of circumstellar envelopes are sufficiently stable to survive decompositions due to stellar UV radiaiton, cosmic rays, C-shocks etc. for a long time (≥ 10^7 year) of their migration to diffuse clouds and seems to disagree with the consensus in the field of interstellar grains. The stability of molecules and aggregates in the diffuse interstellar medium will be discussed. Duley, W. W. 2006, Faraday Discuss. 133, 415 Zhen,J., Castellanos, P., Paardekooper, D. M., Linnartz, H., Tielens, A. G. G. M. 2014, ApJL, 797, L30 Huang, J., Oka, T. 2015, Mol. Phys. 113, 2159 Guzmán, V. V., Pety, J., Goicoechea, J. R., Gerin, M., Roueff, E., Gratier, P., Öberg, K. I. 2015, ApJL, 800, L33 L. Ziurys has sent us many papers beginning Ziurys, L. M. 2006, PNAS 103, 12274 indicating she had long been a proponent of the idea. Campbell, E. K., Holz, M., Maier, J. P., Gerlich, D., Walker, G. A. H., Bohlender, D, 2016, ApJ, in press Draine, B. T. 2003

  19. Anthropopression markers in lake bottom sediments

    Science.gov (United States)

    Nadolna, Anna; Nowicka, Barbara

    2014-05-01

    Lakes are vulnerable to various types of anthropogenic disturbances. Responses of lake ecosystems to environmental stressors are varied and depend not only on the type of a factor but also on the lake natural resistance to degradation. Within the EULAKES project an evaluation of anthropogenic stress extent in a flow-through, postglacial, ribbon lake (Lake Charzykowskie) was carried out. It was assumed, that this impact manifests unevenly, depending on a type and degree of the pressure on the shore zones, water quality of tributaries, lake basin shape and dynamics of a water movement. It was stated, that anthropogenic markers are substances accumulated in bottom sediments as a result of allochthonous substances inflow from the catchment and atmosphere. Along the selected transects 105 samples from the top layer of sediments (about 20 cm) was collected representing the contemporary accumulation (about 15 years). The content of selected chemical elements and compounds was examined, including nutrients (TN and TP), heavy metals (arsenic, cadmium, lead, chromium, nickel, copper, zinc, mercury, iron, and manganese) and pesticides (DDT, DDD, DDE, DMDT , γ-HCH). The research was conducted in the deepest points of each lake basin and along the research transects - while choosing the spots, the increased intensity of anthropogenic impact (ports, roads with heavy traffic, wastewater discharge zones, built-up areas) was taken into consideration. The river outlets to the lake, where there are ecotonal zones between limnic and fluvial environment, were also taken into account. Analysis of the markers distribution was carried out against the diversity of chemical characteristics of limnic sediments. Ribbon shape of the lake basin and the dominant wind direction provide an opportunity of easy water mixing to a considerable depth. Intensive waving processes cause removal of the matter from the littoral zone towards lake hollows (separated by the underwater tresholds), where the

  20. 33 CFR 165.1405 - Regulated Navigation Areas and Security Zones; Designated Escorted Vessels-Philippine Sea and...

    Science.gov (United States)

    2010-07-01

    ... Security Zones; Designated Escorted Vessels-Philippine Sea and Apra Harbor, Guam (including Cabras Island... Areas and Security Zones; Designated Escorted Vessels-Philippine Sea and Apra Harbor, Guam (including... point of origin. (2) Apra Harbor, Guam—All waters from surface to bottom of Apra Harbor, Guam,...

  1. Standing stock of deep-sea metazoan meiofauna in the Sulu Sea and adjacent areas

    Science.gov (United States)

    Shimanaga, Motohiro; Nomaki, Hidetaka; Suetsugu, Kishiko; Murayama, Masafumi; Kitazato, Hiroshi

    2007-01-01

    Standing stocks of deep-sea metazoan meiofauna were investigated in the Sulu Sea, one of the most isolated marginal basins with comparably warm bottom-water temperatures (˜10 °C) at depths below 1000 m. A decline in the abundance and biomass of organisms with increasing water depth occurred in the basin, but the abundances at bathyal and abyssal sites in the Sulu Basin appeared to be lower than standard values worldwide when adjusted for water depth. There is no significant correlation between meiofaunal abundance and the concentration of chloroplastic pigment equivalents (CPE) in the sediment, an indicator of the amount of organic matter derived from primary production. The ratios of meiofaunal abundance to CPE concentration at the sampling sites were as small as those observed at comparable depths in the Red Sea. These suggest that the quantity of "food" is not a primary factor limiting the density of organisms in the basin. It is hypothesized that a higher respiratory activity of benthos caused by warm bottom water and a lower food quality could be important factors regulating the metazoan meiofaunal standing stocks in the Sulu Sea.

  2. Spectroscopy of singly, doubly, and triply bottom baryons

    CERN Document Server

    Wei, Ke-Wei; Liu, Na; Wang, Qian-Qian; Guo, Xin-Heng

    2016-01-01

    Recently, many singly bottom baryons have been established experimentally, but no doubly or triply bottom baryon has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. (For example, we write the mass of $\\Omega_{bbb}$ as a function of the masses of well established light baryons ($\\Sigma^{*}$, $\\Xi^{*}$, $\\Omega$) and singly bottom baryons ($\\Sigma_b^{*}$, $\\Xi_b^{*}$), and give its value to be 14788$\\pm$80 MeV.) After that, we calculate the values of Regge slopes and Regge intercepts for singly, doubly, and triply bottom baryons. (Regge intercepts and slopes, which are usually regarded as fundamental constants of hadron dynamics, are useful for many spectral and nonspectral purposes.) Then, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. The isospin splitting is also determined, $M_{\\Xi_{bb}^{-}}-M_{\\Xi_{...

  3. Quo vadis NW Black Sea benthic ecosystems?

    Science.gov (United States)

    Traian Gomoiu, Marian

    2016-04-01

    The author briefly presents a general review on the evolution trends of benthic ecosystems at the Romanian Black Sea coast, referring to some recent data from the literature. The Black Sea represents a "unicum hydrobiologicum" by some of its basic characteristics, such as: 1. a large semi-enclosed basin with an intense exchange of waters; 2. a sea receiving a large amount of fresh water, especially in its northwestern sector, brought by the Danube, Dnieper and Dniester Rivers; 3. a large meromictic sea - euxinic-azoic below depths of 150 - 200 m; 4. around the sea there is a large filter-holding belt consisting of bivalves (Mytilus galloprovincialis and Modiolula phaseolina); 5. a sea having in its northwestern sector a large area covered by red algae of the genus Phyllophora; 6. a sea undergoing, in the last 50 years, intense environmental pressures (pollution by large rivers and direct discharges of wastewater from urban areas, the development of maritime traffic, overfishing by bottom trawling, coastal facilities and especially by many defense works of the new port); 7. a sea registering in the last decades of the past century many events of eutrophication; 8. a sea enriching its biodiversity by alien species. After the political and socio-economic changes triggered by the events of 1989 and especially after Romania's accession to EU, the state of the northwestern Black Sea coastal ecosystems, has recorded positive changes: • Decrease in environmental pressures; • Decreasing pollutant / fertilizing discharges into the Danube; • Reduction of domestic sewage quantities from coastal settlements; • Improvement in the quality of the wastewater discharged into the sea; • Reduction of active fishing by bottom trawling; • Adopting and implementing a national / international set of guidelines concerning marine environment; • Adopting regulations on the protection of the marine environment against pollution in marine economy: transport / shipping, tourism

  4. THE RE-DERIVATION OF THE VORTICITY EQUATION OF THE LAYERED FLOW OF THE SHALLOW SEA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The scale analysis of the layered flow problem of the shallow sea shows that the parameter of EV represented the relative thickness of the friction layer is the little value larger than Rossby number. This illustrates that they are not ignorable and the important control factors of the layered flow although friction effect is only limited within interface Ekman layer and bottom Ekman layer. Using larger little parameter EV as the little perturbation parameter is more reasonable than using the classical Rossby number ε. By using the perturbation expansion and doing the researches of the structure of the Ekman layer on the sea surface, sea bottom and interface, a group of new layered flow vorticity equation is derived. It combines the vorticity of the flow of every layer, the inclination of the interface, the inclination of the sea bottom and the wind stress vorticity on the sea surface. Different from the conventional vorticity equation, which derived by using Rossby number as little parameter and is applied to large scale motion, it allows relatively large interfaces fluctuation, even it is applied to the problem that interface touch the bottom or touch the sea surface.

  5. Salinization forced anoxia in the Sea of Aral, the Dead Sea and the Urmia Lake: a temporal feature of the salt lakes development under the Global Change?

    Science.gov (United States)

    Yakushev, Evgeniy; Ghaffari, Peygham; Zavialov, Petr; Kurbaniyazov, Abilgazi

    2016-04-01

    The Sea of Aral is undergone a process of its volume decrease and salinization started about 30 years ago. In the remained now lake in the former deepest part of the Sea the salinity increased from about 8 PSU in 1990 to 120 PSU in the surface layer, and 240 PSU in the bottom layer in 2015. On top of an increase of salinity, there was formed a sulfidic zone in the bottom layer, that was separated from the upper layer by an extremely strong halocline (more than 50 PSU in 100 cm). The reason of this halocline might be an influx of the heavy high salinity water formed in summer in the shallower part of the Aral Sea to the bottom layer of the deeper part of the Sea through a strait between them. The similar processes could take place in the Urmia Lake, where salinity increased from 120 PSU in 2000 to about 350-400 PSU in 2015. This lake also consists from a shallow and deep parts connected by a channel in the dam, and where there was also reported anoxia. And finally, the Dead Sea demonstrates a further development happened after the shallower Southern part of the Sea was totally evaporated. After 1993 the vertical mixing started to occur down to the bottom layer, and the lake regime changed from meromictic to monomictic, that resulted in aeration of the bottom layer. In this work we compare interannual changes of the main salinity components in the 3 water bodies and analyze results of the vertical chemical structure of the Sea of Aral studied in 2015.

  6. Visual inspection of sea bottom structures by an autonomous underwater vehicle.

    Science.gov (United States)

    Foresti, G L

    2001-01-01

    This paper describes a vision-based system for inspections of underwater structures, e.g., pipelines, cables, etc., by an autonomous underwater vehicle (AUV). Usually underwater inspections are performed by remote operated vehicles (ROVs) driven by human operators placed in a support vessel. However, this task is often challenging, especially in conditions of poor visibility or in presence of strong currents. The system proposed allows the AUV to accomplish the task in autonomy. Moreover, the use of a three-dimensional (3-D) model of the environment and of an extended Kalman filter (EKF) allows the guidance and the control of the vehicle in real time. Experiments done on real underwater images have demonstrated the validity of the proposed method and its efficiency in the case of critical and complex situations.

  7. Mapping of sea bottom topography over western offshore, India using TOPEX/ERS-1 altimeter data

    Digital Repository Service at National Institute of Oceanography (India)

    Mohanty, K.K.; Majumdar, T.J.; Kunte, P.D.; Srivastava, A.K.

    convolution model using satellite altimeter data over the Indian offshore region. The study used TOPEX/POSEIDON as well as ERS-1 altimeter data, along with National Geophysical Data Centre (NGDC), USA ship-borne bathymetry data. The altimeter range data...

  8. Drivers of the dynamics of diazotrophs and denitrifiers in North Sea bottom waters and sediments

    NARCIS (Netherlands)

    Fan, H.; Bolhuis, H.; Stal, L.J.

    2015-01-01

    The fixation of dinitrogen (N2) and denitrification are two opposite processes in the nitrogen cycle. The former transfers atmospheric dinitrogen gas into bound nitrogen in the biosphere, while the latter returns this bound nitrogen back to atmospheric dinitrogen. It is unclear whether or not these

  9. Visual inspection of sea bottom structures by an autonomous underwater vehicle.

    Science.gov (United States)

    Foresti, G L

    2001-01-01

    This paper describes a vision-based system for inspections of underwater structures, e.g., pipelines, cables, etc., by an autonomous underwater vehicle (AUV). Usually underwater inspections are performed by remote operated vehicles (ROVs) driven by human operators placed in a support vessel. However, this task is often challenging, especially in conditions of poor visibility or in presence of strong currents. The system proposed allows the AUV to accomplish the task in autonomy. Moreover, the use of a three-dimensional (3-D) model of the environment and of an extended Kalman filter (EKF) allows the guidance and the control of the vehicle in real time. Experiments done on real underwater images have demonstrated the validity of the proposed method and its efficiency in the case of critical and complex situations. PMID:18244834

  10. Bottom-up Initiatives for Photovoltaic: Incentives and Barriers

    Directory of Open Access Journals (Sweden)

    Kathrin Reinsberger

    2014-06-01

    Full Text Available When facing the challenge of restructuring the energy system, bottom-up initiatives can aid the diffusion of decentralized and clean energy technologies. We focused here on a bottom-up initiative of citizen-funded and citizen-operated photovoltaic power plants. The project follows a case study-based approach and examines two different community initiatives. The aim is to investigate the potential incentives and barriers relating to participation or non-participation in predefined community PV projects. Qualitative, as well as quantitative empirical research was used to examine the key factors in the further development of bottom-up initiatives as contributors to a general energy transition.

  11. Axial Force at the Vessel Bottom Induced by Axial Impellers

    OpenAIRE

    I. Fořt; P. Hasal; A. Paglianti; F. Magelli

    2008-01-01

    This paper deals with the axial force affecting the flat bottom of a cylindrical stirred vessel. The vessel is equipped with four radial baffles and is stirred with a four 45° pitched blade impeller pumping downwards. The set of pressure transducers is located along the whole radius of the flat bottom between two radial baffles. The radial distribution of the dynamic pressures indicated by the transducers is measured in dependence on the impeller off-bottom clearance and impeller speed.It fol...

  12. Comparison of sea-level measurements using microwave radar and subsurface pressure gauge deployed in Mandovi estuary in Goa, Central West Coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Mehra, P.; Agarvadekar, Y.; Luis, R.; Nadaf, L.

    measurement of atmospheric pressure along with sub-bottom absolute pressure gauge. The radar gauge has advantages over other type of gauges with regard to easy installation, maintenance and also sea level measurements are absolute and could be given precedence...

  13. Numerical study on inter-tidal transports in coastal seas

    Science.gov (United States)

    Mao, Xinyan; Jiang, Wensheng; Zhang, Ping; Feng, Shizuo

    2016-06-01

    Inter-tidal (subtidal) transport processes in coastal sea depend on the residual motion, turbulent dispersion and relevant sources/sinks. In Feng et al. (2008), an updated Lagrangian inter-tidal transport equation, as well as new concept of Lagrangian inter-tidal concentration (LIC), has been proposed for a general nonlinear shallow water system. In the present study, the LIC is numerically applied for the first time to passive tracers in idealized settings and salinity in the Bohai Sea, China. Circulation and tracer motion in the three idealized model seas with different topography or coastline, termed as `flat-bottom', `stairs' and `cape' case, respectively, are simulated. The dependence of the LIC on initial tidal phase suggests that the nonlinearities in the stairs and cape cases are stronger than that in the flat-bottom case. Therefore, the `flat-bottom' case still meets the convectively weakly nonlinear condition. For the Bohai Sea, the simulation results show that most parts of it still meet the weakly nonlinear condition. However, the dependence of the LIS (Lagrangian inter-tidal salinity) on initial tidal phase is significant around the southern headland of the Liaodong Peninsula and near the mouth of the Yellow River. The nonlinearity in the former region is mainly related to the complicated coastlines, and that in the latter region is due to the presence of the estuarine salinity front.

  14. Primary production calculations for sea ice from bio-optical observations in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Susann Müller

    2016-09-01

    Full Text Available Abstract Bio-optics is a powerful approach for estimating photosynthesis rates, but has seldom been applied to sea ice, where measuring photosynthesis is a challenge. We measured absorption coefficients of chromophoric dissolved organic matter (CDOM, algae, and non-algal particles along with solar radiation, albedo and transmittance at four sea-ice stations in the Gulf of Finland, Baltic Sea. This unique compilation of optical and biological data for Baltic Sea ice was used to build a radiative transfer model describing the light field and the light absorption by algae in 1-cm increments. The maximum quantum yields and photoadaptation of photosynthesis were determined from 14C-incorporation in photosynthetic-irradiance experiments using melted ice. The quantum yields were applied to the radiative transfer model estimating the rate of photosynthesis based on incident solar irradiance measured at 1-min intervals. The calculated depth-integrated mean primary production was 5 mg C m–2 d–1 for the surface layer (0–20 cm ice depth at Station 3 (fast ice and 0.5 mg C m–2 d–1 for the bottom layer (20–57 cm ice depth. Additional calculations were performed for typical sea ice in the area in March using all ice types and a typical light spectrum, resulting in depth-integrated mean primary production rates of 34 and 5.6 mg C m–2 d–1 in surface ice and bottom ice, respectively. These calculated rates were compared to rates determined from 14C incorporation experiments with melted ice incubated in situ. The rate of the calculated photosynthesis and the rates measured in situ at Station 3 were lower than those calculated by the bio-optical algorithm for typical conditions in March in the Gulf of Finland by the bio-optical algorithm. Nevertheless, our study shows the applicability of bio-optics for estimating the photosynthesis of sea-ice algae.

  15. The sea ice thickness distribution in the northwestern Weddell Sea

    Science.gov (United States)

    Lange, M. A.; Eicken, H.

    1991-03-01

    We present new data on distribution of snow and sea ice thicknesses in the northwestern Weddell Sea. The data were obtained through direct measurements along 19 profiles, each approximately 100 m long on 17 different floes located between 54°-46°W and 59°-64°S. The overall probability density functions (PDFs) for ice thicknesses reflect the complex mixture of first-, second-, and multi-year ice to be expected in the outflowing branch of the Weddell Gyre. Further differentiation of the data reveals four distinct thickness classes which reflect differences in the formation and subsequent histories of the ice encountered. These classes (I-IV) represent strongly deformed first year ice, less deformed first- and second-year ice, and deformed second- or multi-year ice, respectively. Each of the classes is characterized by a specific set of quantities related to ice texture and surface snow characteristics and by distinct PDFs for snow and ice thicknesses. In addition, geometric surface and bottom roughness characteristics differ significantly for each of the floe classes.

  16. Components in Antineoplastic Actinomycete Strain(N2010-37)of Bottom Mud in Mangrove

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhong-liu; JIN Bei; YIN Wen-qing; FU Chun-yan; FENG Hua-fen

    2011-01-01

    Objective To study the antitumor components from an actinomycete strain(N2010-37)of bottom mud in Zhanjiang Mangrove,South China Sea.Methods The components were isolated and purified by chromatographic techniques and recrystallization,and the structures were identified by spectral methods together with physicochemical analyses.The antitumor effects of these components were tested in vitro by MTT method.Results Three compounds were identified including two anthrones and one novel lactone.They are(3S,4R,7R,8R,9S)-3,8-dihydroxy-4,7,9-trimethyl-2,6-cyclononanediolacetone(1),2-hydroxy-l-methoxy-3-methylanthraquinone(2),and 1,6,8-thihydroxy-3-methyl-anthraquinone(3).Conclusion Compound 1 is a new compound,and compounds 1 and 3 show the favorablecytotoxic activities against human chronic granulocytic leukemia cell line K562 strain by MTT method in vitro.

  17. Monitoring and manipulation of a sublittoral hard bottom biocoenosis in Balsfjord, northern Norway

    Science.gov (United States)

    Sandnes, O. K.; Gulliksen, B.

    1980-03-01

    Sublittoral hard bottom biocoenoses in Balsfjord, Norway (69°31' N, 19°1' E), were monitored using underwater stereophotogrammetry. The study includes manipulation of natural densities of organisms and testing the importance of biological interactions and “key species ” for the structure of biocoenoses. Underwater photography has the advantages of being a non-destructive method, but it is selective because small or hidden organisms cannot always be observed. Field experiments with exclusion of organisms from cages seem suitable for testing hypotheses concerning which animals are “key species ” in certain biocoenoses. Sea-urchins (Strongylocentrotus droebachiensis, S. pallidus) were suspected to be “key species ” in the present study, and their removal from cages caused an increase in abundance of barnacles (Balanus balanoides), the limpet Acmaea testudinalis and algal cover.

  18. Differential recolonization of Atlantic intertidal habitats after disturbance reveals potential bottom-up community regulation.

    Science.gov (United States)

    Petzold, Willy; Scrosati, Ricardo A

    2014-01-01

    In the spring of 2014, abundant sea ice that drifted out of the Gulf of St. Lawrence caused extensive disturbance in rocky intertidal habitats on the northern Atlantic coast of mainland Nova Scotia, Canada. To monitor recovery of intertidal communities, we surveyed two wave-exposed locations in the early summer of 2014. Barnacle recruitment and the abundance of predatory dogwhelks were low at one location (Tor Bay Provincial Park) but more than 20 times higher at the other location (Whitehead). Satellite data indicated that the abundance of coastal phytoplankton (the main food source for barnacle larvae) was consistently higher at Whitehead just before the barnacle recruitment season, when barnacle larvae were in the water column. These observations suggest bottom-up forcing of intertidal communities. The underlying mechanisms and their intensity along the NW Atlantic coast could be investigated through studies done at local and regional scales.

  19. Differential recolonization of Atlantic intertidal habitats after disturbance reveals potential bottom-up community regulation

    Science.gov (United States)

    Petzold, Willy; Scrosati, Ricardo A.

    2014-01-01

    In the spring of 2014, abundant sea ice that drifted out of the Gulf of St. Lawrence caused extensive disturbance in rocky intertidal habitats on the northern Atlantic coast of mainland Nova Scotia, Canada. To monitor recovery of intertidal communities, we surveyed two wave-exposed locations in the early summer of 2014. Barnacle recruitment and the abundance of predatory dogwhelks were low at one location (Tor Bay Provincial Park) but more than 20 times higher at the other location (Whitehead). Satellite data indicated that the abundance of coastal phytoplankton (the main food source for barnacle larvae) was consistently higher at Whitehead just before the barnacle recruitment season, when barnacle larvae were in the water column. These observations suggest bottom-up forcing of intertidal communities. The underlying mechanisms and their intensity along the NW Atlantic coast could be investigated through studies done at local and regional scales. PMID:26213609

  20. Gulf of Maine Cooperative Bottom Longline Survey Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database is for a bottom longline (fixed gear) survey executed in the western and central Gulf of Maine targeting complex rocky habitats. The survey is...

  1. NEFSC 2005 Winter Bottom Trawl Survey (AL0502, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  2. NEFSC 2009 Fall Bottom Trawl Survey (HB0905, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  3. NMFS Bottom Longline Analytical Dataset Provided to NRDA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories has conducted standardized bottom longline surveys in the Gulf of Mexico and South Atlantic since...

  4. Gear Selectivity of a Longfin Squid Bottom Trawl

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Loligo pealeii (longfin inshore squid) co-occurs with Atlantic butterfish (Peprilus triacanthus) throughout the year and discarding in the L. pealeii bottom trawl...

  5. Bottom production mechanism for same-sign dileptons

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, C.E.M.; Martins Simoes, J.A. (Rio de Janeiro Univ. (Brazil). Inst. de Fisica); Garcia Canal, C.A. (La Plata Univ. Nacional (Argentina))

    1983-01-22

    Bottom production is investigated as a possible mechanism for same-sign prompt dileptons in neutrino reactions. A partonlike model is able to account for the CDHS dilepton signal with inputs compatible with other data.

  6. NEFSC 2015 Fall Bottom Trawl Survey (HB1506, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  7. NEFSC 2000 Fall Bottom Trawl Survey (Al0006, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  8. NEFSC 2005 Fall Bottom Trawl Survey (AL0508, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  9. NEFSC 1998 Fall Bottom Trawl Survey (AL9811, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  10. NEFSC 2013 Fall Bottom Trawl Survey (HB1304, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  11. NEFSC 2012 Spring Bottom Trawl Survey (HB1201, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  12. NEFSC 2013 Spring Bottom Trawl Survey (HB1301, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  13. NEFSC 2008 Fall Bottom Trawl Survey (AL0803, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  14. NEFSC 2002 Fall Bottom Trawl Survey (AL0210, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  15. NEFSC 2014 Spring Bottom Trawl Survey (HB1401, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  16. NEFSC 2005 Spring Bottom Trawl Survey (AL0504, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  17. NEFSC 2007 Bottom Trawl Survey Calibration (HB0711, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  18. NEFSC 2011 Spring Bottom Trawl Survey (HB1102, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  19. NEFSC 2004 Winter Bottom Trawl Survey (AL0401, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  20. NEFSC 2004 Spring Bottom Trawl Survey (AL0403, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  1. NEFSC 2011 Fall Bottom Trawl Survey (HB1105, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  2. NEFSC 2008 Fall Bottom Trawl Survey (HB0807, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  3. NEFSC 1999 Fall Bottom Trawl Survey (AL9911, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  4. NEFSC 2005 Fall Bottom Trawl Survey (AL0509, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  5. NEFSC 2009 Spring Bottom Trawl Survey (HB0901, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  6. NEFSC 2008 Spring Bottom Trawl Survey (HB0802, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  7. NEFSC 2000 Fall Bottom Trawl Survey (AL0007, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  8. NEFSC 2004 Fall Bottom Trawl Survey (AL0409, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  9. NEFSC 2014 Fall Bottom Trawl Survey (HB1405, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  10. NEFSC 2015 Spring Bottom Trawl Survey (HB1501, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  11. NEFSC 2001 Fall Bottom Trawl Survey (AL0110, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  12. NEFSC 2012 Fall Bottom Trawl Survey (HB1206, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  13. NEFSC 2002 Winter Bottom Trawl Survey (AL0203, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  14. Nanoelectronics: Thermoelectric Phenomena in «Bottom-Up» Approach

    OpenAIRE

    Yu.A. Kruglyak; P.A. Kondratenko; Yu.М. Lopatkin

    2014-01-01

    Thermoelectric phenomena of Seebeck and Peltier, quality indicators and thermoelectric optimization, ballistic and diffusive phonon heat current are discussed in the frame of the «bottom-up» approach of modern nanoelectronics.

  15. NEFSC 2007 Bottom Trawl Survey Calibration (HB0710, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  16. sir-06-5129_depth_bottom_trinidad_con

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set consists of contours of lines of equal depth to the bottom of the Trinidad Sandstone, the contact between the Trinidad Sandstone...

  17. NEFSC 2002 Spring Bottom Trawl Survey (AL0204, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  18. NEFSC 2010 Spring Bottom Trawl Survey (HB1002, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  19. Base Stress of the Opened Bottom Cylinder Structures

    Institute of Scientific and Technical Information of China (English)

    刘建起; 孟晓娟

    2004-01-01

    The base stress of the opened bottom cylinder structure differs greatly from that of the structure with a closed bottom. By investigating the inner soil pressure on the cylinder wall and the base stress of the cylinder base, which were obtained from the model experiments, the interactions among the filler inside the cylinder,subsoil and cylinder are analyzed. The adjusting mechanism of frictional resistance between the inner filler and the wall of the cylinder during the overturning of the cylinder is discussed. Based on the experimental study, a method for calculating the base stress of the opened bottom cylinder structure is proposed. Meanwhile, the formulas for calculating the effective anti-overturning ratio of the opened bottom cylinder are derived.

  20. Nanoelectronics: Thermoelectric Phenomena in «Bottom-Up» Approach

    Directory of Open Access Journals (Sweden)

    Yu.A. Kruglyak

    2014-04-01

    Full Text Available Thermoelectric phenomena of Seebeck and Peltier, quality indicators and thermoelectric optimization, ballistic and diffusive phonon heat current are discussed in the frame of the «bottom-up» approach of modern nanoelectronics.

  1. NEFSC 2003 Fall Bottom Trawl Survey (AL0305, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  2. 49 CFR 178.811 - Bottom lift test.

    Science.gov (United States)

    2010-10-01

    ... truck with the forks centrally positioned and spaced at three quarters of the dimension of the side of... bottom lift test. The IBC must be loaded to 1.25 times its maximum permissible gross mass, the load...

  3. NEFSC 2008 Spring Bottom Trawl Survey (AL0801, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  4. NEFSC 2003 Spring Bottom Trawl Survey (DE0303, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC bottom trawl survey is a fisheries independent, multi-species survey that provides the primary scientific data for fisheries assessments in the U.S....

  5. Method for treatment of oil well bottom zones

    International Nuclear Information System (INIS)

    The patent deals with a method for the inactivation of sulfate reducing bacteria in an oil well bottom zone. According to the invention the feeding of a bactericidal agent into the well bottom zone is combined with gamma radiation in the zone where the radiation dose is at least 150 krad. A pressure in the range from 2 to 50 MPa is maintained during irrradiation. 1 tab

  6. Controlling near shore nonlinear surging waves through bottom boundary conditions

    CERN Document Server

    Mukherjee, Abhik; Kundu, Anjan

    2016-01-01

    Instead of taking the usual passive view for warning of near shore surging waves including extreme waves like tsunamis, we aim to study the possibility of intervening and controlling nonlinear surface waves through the feedback boundary effect at the bottom. It has been shown through analytic result that the controlled leakage at the bottom may regulate the surface solitary wave amplitude opposing the hazardous variable depth effect. The theoretical results are applied to a real coastal bathymetry in India.

  7. Marine plastic litter as an artificial hard bottom fouling ground

    Science.gov (United States)

    Harms, J.

    1990-09-01

    20 fouling organisms were observed on plastic litter dredged from the Elbe estuary during July 1990; 60% of the species were typical sessile hard bottom organisms. Most individuals found on this artificial hard bottom were barnacles ( Balanus crenatus, Elminius modestus), the mussel Mytilus edulis and the polychaete Lanice conchilega. All individuals were juveniles which had settled only recently on the plastics. The earliest settlers were not much older than 4 8 weeks.

  8. Polar bear and walrus response to the rapid decline in Arctic sea ice

    Science.gov (United States)

    Oakley, K.; Whalen, M.; Douglas, D.; Udevitz, M.; Atwood, T.; Jay, C.

    2012-01-01

    The Arctic is warming faster than other regions of the world due to positive climate feedbacks associated with loss of snow and ice. One highly visible consequence has been a rapid decline in Arctic sea ice over the past 3 decades - a decline projected to continue and result in ice-free summers likely as soon as 2030. The polar bear (Ursus maritimus) and the Pacific walrus (Odobenus rosmarus divergens) are dependent on sea ice over the continental shelves of the Arctic Ocean's marginal seas. The continental shelves are shallow regions with high biological productivity, supporting abundant marine life within the water column and on the sea floor. Polar bears use sea ice as a platform for hunting ice seals; walruses use sea ice as a resting platform between dives to forage for clams and other bottom-dwelling invertebrates. How have sea ice changes affected polar bears and walruses? How will anticipated changes affect them in the future?

  9. Changes of near-bottom water properties in polish zone generated by the inflow 2014

    Science.gov (United States)

    Rak, Daniel

    2016-04-01

    Since 11 years, in winter 2014 for the first time large amount of water - more than 200 km3 (Morholtz, 2015), were pushed into the Baltic Sea from the North Sea. This process has been classified as a Major Baltic Inflow (MBI). The inflow water brought to the Baltic Proper large amounts of salt (4 Gt) and oxygen. Oxygen and salt-reach, dense inflow waters are a phenomenon increasingly rare, since the early 80s average occurrence is once per decade. Therefore, the number of measurements both the situation during the process and changes of the water properties after termination of driving forces are limited. Institute of Oceanology PAS observed inflow and changes taking place afterwards during 6 r/v Oceania's cruises in the period December 2014 - December 2015. Refreshing of the bottom layers occurred in the Bornholm Deep and Słupsk Furrow, but in the Gdańsk Deep there was no change in the anoxic layer. In the Bornholm Deep effects of increased amount of oxygen quickly vanished, depleting the concentration of oxygen at a rate of 1 mg/l within a month. The initial high oxygen content of the inflow water (approximately 10 mg/l) was reduced and after 10 months anaerobic conditions returned. In the Słupsk Furrow this process was five times slower than in the Bornholm Deep, rate of the oxygen concentration was 0.2 mg/l per month. At the same time bottom salinity in the Polish zone remained relatively high. In November 2015 appearance of the warm (12 °C) and oxygenated (6 mg/l) layer of water below the halocline in the Bornholm Deep was observed. This inflow resulted in lifting the halocline to a depth that allowed the dense waters to pass through the Słupsk Sill.

  10. Formation of Humic Substances in Weathered MSWI Bottom Ash

    Directory of Open Access Journals (Sweden)

    Haixia Zhang

    2013-01-01

    Full Text Available The study aimed at evaluating the humic substances (HSs content from municipal solid waste incinerator (MSWI bottom ash and its variation with time and the effect of temperature on HSs formation. The process suggested by IHSS was applied to extract HSs from two different bottom ash samples, and the extracted efficiency with NaOH and Na4P2O7 was compared. MSWI bottom ash samples were incubated at 37∘C and 50∘C for 1 year. HSs and nonhumic substances were extracted from the bottom ash sample with different incubated period by 0.1 M NaOH/Na4P2O7. Results show that the rate of humic acid formation increased originally with incubation time, reached a maximum at 12th week under 37∘C and at 18th week under 50∘C, and then decreased with time. More humic acid in MSWI bottom ash was formed under 50∘C incubated condition compared with that incubated under 37∘C. Also, the elemental compositions of HSs extracted from bottom ash are reported.

  11. Separation of a midlevel density current from the bottom of a continental slope.

    Science.gov (United States)

    Stern, M E

    1999-02-16

    The high-salinity water flowing out of the Mediterranean Sea descends to mid depths in the density-stratified ocean, continues as a narrow jet along the Iberian continental slope, and intermittently detaches large-scale eddies (called "Meddies"). This process is important because it maintains the relatively high mean salinity of a major water mass (the "Mediterranean Intermediate Water") in the North Atlantic. Our simplified model of this jet consists of a moving layer with intermediate density rho2 sandwiched between motionless layers of density rho1 rho2. The inshore (anticyclonic) portion of the midlevel jet (in the "rho2-water") rests on an inclined bottom (the continental slope), whereas the (cyclonic) offshore portion rests on the density interface of the stagnant deep (rho3) layer. An inviscid, steady, and finite-amplitude longwave theory is used to show that if the cross-stream topographic slope increases gradually in the downstream direction, then the "rho2-jet" is deflected off the bottom slope and onto the upper density interface of the rho3 layer. The computed magnitude of this separation effect is such as to produce an essentially free jet which is removed from the stabilizing influence of the continental topography. It is therefore conjectured that time-dependent effects (baroclinic instability) will produce further amplification, causing an eddy to detach seaward from the branch of the jet remaining on the slope. PMID:9990002

  12. Light Attenuation Method for 3D data acquisition (LAM3D) of bottom particle deposits

    Science.gov (United States)

    Er, Jenn Wei; Law, Adrian W. K.; Adams, E. Eric; Yang, Yang

    2015-11-01

    We have developed a novel experimental technique, Light Attenuation Method for 3D data acquisition (LAM3D), to acquire three-dimensional spatial characteristics and temporal development of bottom particle deposits. The new technique performs data acquisition with higher spatial and temporal resolution than existing approaches with laser and ultrasonic 3D profilers, and is therefore ideal for laboratory investigations with fast varying changes in the sediment bed, such as the developing deposition profile from sediment clouds commonly formed during dredging or land reclamation projects and the dynamic evolution in movable bed processes in rivers. The principle of the technique is based on the analysis of the light attenuation due to multiple light scattering through the particle deposits layer compared to the clear water column. With appropriate calibration, the particles size and distribution thickness can be quantified by the transmitted light spectrum. In the presentation, we will first show our measurement setup with a light panel for calibrated illumination and a system of DSLR cameras for the light capturing. Subsequently, we shall present the experimental results of fast evolving deposition profile of a barge-disposed sediment cloud upon its bottom impact on the sea bed.

  13. Nitrification in a zeoponic substrate

    Science.gov (United States)

    McGilloway, R. L.; Weaver, R. W.; Ming, D. W.; Gruener, J. E.

    2003-01-01

    Clinoptilolite is a zeolite mineral with high cation exchange capacity used in zeoponic substrates that have been proposed as a solid medium for growing plants or as a fertilizer material. The kinetics of nitrification has not been measured for NH4+ saturated zeoponic substrate. Experiments were conducted to evaluate the production of NO2- and NO3-, and nitrifier populations in zeoponic substrates. Small columns were filled with zeoponic substrate inoculated with a commercial inoculum or soil enrichment culture of nitrifying bacteria. In addition to column studies, a growth chamber study was conducted to evaluate the kinetics of nitrification in zeoponic substrates used to grow radishes (Raphanus sativus L.). The zeoponic substrate provided a readily available source of NH4+, and nitrifying bacteria were active in the substrate. Ammonium oxidation rates in column studies ranged from 5 to 10 micrograms N g-1 substrate h-1, and NO2- oxidation rates were 2 to 9.5 micrograms N g-1 substrate h-1. Rates determined from the growth chamber study were approximately 1.2 micrograms N g-1 substrate h-1. Quantities of NH4+ oxidized to NO2- and NO3- in inoculated zeoponic substrate were in excess of plant up-take. Acidification as a result of NH4+ oxidation resulted in a pH decline, and the zeoponic substrate showed limited buffering capacity.

  14. Some observational results of sea storm current

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ INTRODUCTION Dr. Hollister, a marine geologist of the Woods Hole Oceanographic Institution, first pointed out that there was ocean storm current in the ocean. He found out the wavy texture in the seabed core samples, and suggested that this wavy texture was caused by the high speed sea current in remote antiquity. He then suggested a bold hypothesis that there existed a benthic storm current near the ocean bottom, and presented this hypothesis at the IUGG conference held at San Francisco in 1963. Unfortunately, the attention was not drawn to the hypothesis at the conference, and the hypothesis was criticized as a sheer nonsense.

  15. North Sea Elasmobranchs: distribution, abundance and biodiversity

    OpenAIRE

    Daan, N.; Heessen, H.J.L.; Hofstede, ter, AHM Arthur

    2005-01-01

    Based on data from various international and national surveys, an overview is given of the fine-scale distribution (resolution of 20¿longitude * 10¿ latitude; ¿ 10*10 nm) and trends in abundance of elasmobranch species reported from the North Sea. Presence-absence maps are produced based on 4 surveys, which help to delineate distribution limits of the less common species, while maps in terms of catch rates (International Bottom Trawl Survey data only) are given for the seven most common shark...

  16. The geochemical characteristics of the bottom sediment in the pockmark area of the eastern part of the Gulf of Finland

    OpenAIRE

    Ivanova V. V.; Kirievskaya D. V.; Bolotov A. Ye.

    2011-01-01

    It is the first time pockmark-like structures have been detected in the south-eastern part of the Gulf of Finland with the help of a side-scan sonar and a profile recorder. The analysis of the distribution of microcomponents in the bottom sediment indicates that the pockmark area is located in the geochemical barrier border zone where the reducing medium of the incoming mineralized solution meets the highly oxidizing sea water medium. The hydrodynamic and geochemical processes in the pockmark...

  17. Low voltage transflective blue-phase liquid crystal display with a non-uniform etching substrate

    Science.gov (United States)

    Wang, Jian; Mao, Jiang-Lin; Fan, Hao-Xiang; Wang, Qiong-Hua

    2016-09-01

    A transflective polymer-stabilized blue-phase liquid crystal display (BP-LCD) with a non-uniform etching substrate is proposed. In-plane switching (IPS) electrodes on the bottom substrate are put on the different gaps, and the bottom substrate between the electrodes is etched into different depths in transmissive (T) and reflective (R) regions. This structure can balance the optical phase retardation in the two regions and is helpful to achieve well-matched voltag-dependent transmittance and reflectance curves. This transflective display has high optical efficiency, a wide viewing angle, and low operating voltage (approximately 6 V). Project supported by the National Natural Science Foundation of China (Grant Nos. 61535007 and 61320106015) and the National Basic Research Program of China (Grant No. 2013CB328802).

  18. Modern processes controlling the sea bed sediment formation in Barents Sea

    Science.gov (United States)

    Balanyuk, I.; Dmitrievsky, A.; Shapovalov, S.; Chaikina, O.; Akivis, T.

    2009-04-01

    The Barents Sea is one of the key regions for understanding of the postglacial history of the climate and circulation of the World Ocean. There are the limits of warm North Atlantic waters penetration to the Arctic and a zone of interaction between Atlantic and Arctic waters. The Barents Se's limits are the deep Norwegian Sea in the West, the Spitsbergen Island and the Franz Josef Land and the deep Nansen trough in the North, the Novaya Zemlya archipelago in the East and the North shore of Europe in the South. An analysis of Eurasian-Arctic continental margin shows correspondence between the rift systems of the shelf with those of the ocean. This relation can be observed in the central Arctic region. All the rift systems underlying the sediment basin are expressed in the sea bed relief as spacious and extensive graben valleys burnished by lobes. Two transverse trenches cross both shelf and continental slope, namely the Medvezhinsky trench between Norway and Spitsbergen in the West and the Franz Victoria trench between Spitsbergen and the Franz Josef Land in the North. The Barents and the Kara Seas are connected by the Kara Gate Strait and wide transverse trough of Saint Anna in the North-West. The recent assessment of the eolian solid sediment supply to the Barents Sea is about 0.904 tons. The Barents Sea as a whole should be considered as "starving" in terms of its feeding with solid sediment matter. Observations show the considerable part of the sea bottom to be free of Holocene sediment cover. The more ancient Quaternary units or bedrock can be seen at the bottom surface. This phenomenon is the most typical for arches of relatively shallow elevations. Thick accumulations of new sediments are connected with fjords. The amount of sea ice delivered from the Barents Sea to the Arctic Ocean is 35 km3 a year. This value should be added by iceberg delivery from the North island of Novaya Zemlya, the Franz Josef Land, the Spitsbergen Island and North Norway but most of

  19. Role of sea-ice biota in nutrient and organic material cycles in the northern Baltic Sea.

    Science.gov (United States)

    Kuparinen, Jorma; Kuosa, Harri; Andersson, Agneta; Autio, Riitta; Granskog, Mats A; Ikävalko, Johanna; Kaartokallio, Hermanni; Karell, Kimmo; Leskinen, Elina; Piiparinen, Jonna; Rintala, Janne-Markus; Tuomainen, Jaana

    2007-04-01

    This paper compiles biological and chemical sea-ice data from three areas of the Baltic Sea: the Bothnian Bay (Hailuoto, Finland), the Bothnian Sea (Norrby, Sweden), and the Gulf of Finland (Tvärminne, Finland). The data consist mainly of field measurements and experiments conducted during the BIREME project from 2003 to 2006, supplemented with relevant published data. Our main focus was to analyze whether the biological activity in Baltic Sea sea-ice shows clear regional variability. Sea-ice in the Bothnian Bay has low chlorophyll a concentrations, and the bacterial turnover rates are low. However, we have sampled mainly land-fast level first-year sea-ice and apparently missed the most active biological system, which may reside in deformed ice (such as ice ridges). Our limited data set shows high concentrations of algae in keel blocks and keel block interstitial water under the consolidated layer of the pressure ridges in the northernmost part of the Baltic Sea. In land-fast level sea-ice in the Bothnian Sea and the Gulf of Finland, the lowermost layer appears to be the center of biological activity, though elevated biomasses can also be found occasionally in the top and interior parts of the ice. Ice algae are light limited during periods of snow cover, and phosphate is generally the limiting nutrient for ice bottom algae. Bacterial growth is evidently controlled by the production of labile dissolved organic matter by algae because low growth rates were recorded in the Bothnian Bay with high concentrations of allochthonous dissolved organic matter. Bacterial communities in the Bothnian Sea and the Gulf of Finland show high turnover rates, and activities comparable with those of open water communities during plankton blooms, which implies that sea-ice bacterial communities have high capacity to process matter during the winter period. PMID:17520927

  20. Estuarine circulation in the Taranto Seas.

    Science.gov (United States)

    Pascalis, Francesca De; Petrizzo, Antonio; Ghezzo, Michol; Lorenzetti, Giuliano; Manfè, Giorgia; Alabiso, Giorgio; Zaggia, Luca

    2016-07-01

    The Taranto basin is a shallow water marine system in the South of Italy characterized by the presence of a lagoon environment together with a semi-enclosed bay connected to the Ionian Sea. This marine system experienced over the last few decades strong biochemical pollution and environmental degradation, and it is considered a hotspot study site for economic, ecological and scientific reasons. The aim of this study was to examine, on an annual temporal scale and with high spatial resolution, the main hydrodynamical processes and transport scales of the system by means of a 3D finite element numerical model application, adopting the most realistic forcing available. The model allowed us to assess the role played by baroclinic terms in the basin circulation, describing its estuarine nature. In particular, the main features of water circulation, salinity and temperature distribution, water renewal time and bottom stress were investigated. Our results allowed us to equate this system dynamic to that of a weakly stratified estuary, identifying the main driving sources of this mechanism. The vertical stratification over the whole year was proved to be stable, leading to a dual circulation flowing out on the surface, mainly through Porta Napoli channel, and inflowing on the bottom mainly through Navigabile channel. This process was responsible also for the renewal time faster on the bottom of the Mar Piccolo basin than the surface. Due to the great importance of the Taranto basin for what concerns sediment pollution, also the effect of currents in terms of bottom stress was investigated, leading to the conclusion that only in the inlets area the values of bottom stress can be high enough to cause erosion. PMID:26408109

  1. Maintainable substrate carrier for electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen-An; Abas, Emmanuel Chua; Divino, Edmundo Anida; Ermita, Jake Randal G.; Capulong, Jose Francisco S.; Castillo, Arnold Villamor; Ma, Diana Xiaobing

    2016-08-02

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  2. Past and present Aral Sea

    Science.gov (United States)

    Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

    2013-04-01

    organized in 2005-2009 sixth expeditions for complex remote sensing and ground investigations Aral Sea former bottom that were complemented in 2010 -2011 by two expeditions with GFZ. As a result, the landscape, soils and environment mapping was done with determination of ecologically unstable zones and assessment total change of lands situation compared with the pre-independence time. Moreover - methodic of monitoring water, environment and hydro geological indicators on the all deltas area was elaborated, organized its testing and combined with remote sensing data on Amudarya delta for 2009-2012. It permits to SIC ICWC to organize systematic permanent (decadal) monitoring and recording of size, volume and level of water in Aral Sea. Since the beginning of regular observations over the Aral Sea level, 2 periods can be emphasized: 1. Conditionally natural period - 1911-1960 - characterized by a relatively stable hydrological regime, with fluctuations in the level around 53 m and the range of inter-annual fluctuations at no more than 1 m., when the sea received annually about a half of the run-off in the Syrdarya and Amudarya Rivers, i.e. 50-60 km3/yr. 2. Intensive anthropogenic impact period - since the 1960s, a vast extension of irrigable land was carried out in Central Asia that resulted in intensive diversion of river run-off. Since then, the sea level has been falling steadily, causing a dramatic reduction in the water surface area, a decrease in water volume and depths, great changes in shoreline configuration and an expansion of the desert areas adjacent to the Aral Sea. From 1960-1985, when the sea was an integral water body, slight lowering in the sea level took place until the 1970s, when the sea-level decreased with the mean level lowering 1 m. The desiccation process accelerated visibly from the mid 1970s. In 1975-1980, the level decreased by 0.65 m a year on average. Moreover, the level dropped greatly, when the run-off of the Amudarya did not reach the Aral Sea

  3. Glaciomarine sedimentation and bottom current activity on the north-western and northern continental margins of Svalbard during the late Quaternary

    Science.gov (United States)

    Chauhan, Teena; Noormets, Riko; Rasmussen, Tine L.

    2016-04-01

    Palaeo-bottom current strength of the West Spitsbergen Current (WSC) and the influence of the Svalbard-Barents Sea Ice Sheet (SBIS) on the depositional environment along the northern Svalbard margins are poorly known. Two gravity cores from the southern Yermak Plateau and the upper slope north of Nordaustlandet, covering marine isotope stage (MIS) 1 to MIS 5, are investigated. Five lithofacies, based on grain size distribution, silt/clay ratio, content and mean of sortable silt (SS), are distinguished to characterise the contourite-dominated sedimentary environments. In addition, depositional environments are described using total organic carbon (TOC), total sulphur (TS) and calcium carbonate (CaCO3) contents of sediments. Facies A, containing coarse SS, suggests strong bottom current activity and good bottom water ventilation conditions as inferred from low TOC content. This facies was deposited during the glacial periods MIS 4, MIS 2 and during the late Holocene. Facies B is dominated by fine SS indicating weak bottom current and poor ventilation (cf. high TOC content of 1.2-1.6%), and correlates with the MIS 4/3 and MIS 2/1 transition periods. With an equal amount of clay and sand, fine SS and high content of TOC, facies C indicates reduced bottom current strength for intervals with sediment supply from proximal sources such as icebergs, sea ice or meltwater discharge. This facies was deposited during the last glacial maximum. Facies D represents mass-flow deposits on the northern Svalbard margin attributed to the SBIS advance at or near the shelf edge. Facies E sediments indicating moderate bottom current strength were deposited during MIS 5 and MIS 3, and during parts of MIS 2. This first late Quaternary proxy record of the WSC flow and sedimentation history from the northern Svalbard margin suggests that the oceanographic conditions and ice sheet processes have exerted first-order control on sediment properties.

  4. BOTTOM SHEAR STRESS UNDER WAVE-CURRENT INTERACTION

    Institute of Scientific and Technical Information of China (English)

    LIANG Bing-chen; LI Hua-jun; LEE Dong-yong

    2008-01-01

    The present work adopts the COHERENS-SWAN model developed by the first author through coupling three-dimensional hydrodynamic model (COHERENS) and third-generation wave model (SWAN). Inside the COHERENS-SWAN, the SWAN is regarded as a subroutine and the time- and space-varying current velocity and surface elevation are obtained from the COHERENS. Wave-enhanced bottom shear stress, wave induced surface mixing length and wave dependent surface drag coefficient have been introduced into the COHERENS. Secondly, as wave-enhanced bottom shear stress ("bottom shear stress" described as BSS sometimes in this article) is concerned, a modified bottom shear stress Grant and Madsen model which introduces random wave field is given and introduced to COHERENS-SWAN. COHERENS-SWAN is also adopted to simulate three-dimensional flow in the Yellow River Delta with wave-current co-existing. Four numerical experiments were given to study the effects of wave-current interaction on enhancing bottom shear stress. The simulated current velocities, wave height and wave period match well with field measurement data. The simulated significant wave height and wave period for the case with considering the effects of current can give better agreement with measurement data than the case without involving the effects of current. The introduction of random wave generates lower the bottom shear stress than the case without introducing it. There are obvious differences between bottom shear stress of two way interaction and one way interaction. Velocity field obtained by the COHERENS-SWAN is reasonable according to previous studies and measurements.

  5. Characterization of microbial arsenate reduction in the anoxic bottom waters of Mono Lake, California

    Science.gov (United States)

    Hoeft, S.E.; Lucas, F.; Hollibaugh, J.T.; Oremland, R.S.

    2002-01-01

    Dissimilatory reduction of arsenate (DAsR) occurs in the arsenic-rich, anoxic water column of Mono Lake, California, yet the microorganisms responsible for this observed in situ activity have not been identified. To gain insight as to which microorganisms mediate this phenomenon, as well as to some of the biogeochemical constraints on this activity, we conducted incubations of arsenate-enriched bottom water coupled with inhibition/amendment studies and Denaturing Gradient Gel Electrophoresis (DGGE) characterization techniques. DAsR was totally inhibited by filter-sterilization and by nitrate, partially inhibited (~50%) by selenate, but only slightly (~25%) inhibited by oxyanions that block sulfate-reduction (molybdate and tungstate). The apparent inhibition by nitrate, however, was not due to action as a preferred electron acceptor to arsenate. Rather, nitrate addition caused a rapid, microbial re-oxidation of arsenite to arsenate, which gave the overall appearance of no arsenate loss. A similar microbial oxidation of As(III) was also found with Fe(III), a fact that has implications for the recycling of As(V) in Mono Lake's anoxic bottom waters. DAsR could be slightly (10%) stimulated by substrate amendments of lactate, succinate, malate, or glucose, but not by acetate, suggesting that the DAsR microflora is not electron donor limited. DGGE analysis of amplified 16S rDNA gene fragments from incubated arsenate-enriched bottom waters revealed the presence of two bands that were not present in controls without added arsenate. The resolved sequences of these excised bands indicated the presence of members of the epsilon (Sulfurospirillum) and delta (Desulfovibrio) subgroups of the Proteobacteria, both of which have representative species that are capable of anaerobic growth using arsenate as their electron acceptor.

  6. 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.

  7. Bottom-Up Cost Analysis of a High Concentration PV Module; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, K.; Woodhouse, M.; Lee, H.; Smestad, G.

    2015-04-13

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.65/Wp(DC) manufacturing costs for our model HCPV module design with today’s capabilities, and find that reducing cell costs and increasing module efficiency offer the promising pathways for future cost reductions. Cell costs could be significantly reduced via an increase in manufacturing scale, substrate reuse, and improved manufacturing yields. We also identify several other significant drivers of HCPV module costs, including the Fresnel lens primary optic, module housing, thermal management, and the receiver board. These costs could potentially be lowered by employing innovative module designs.

  8. A bottom-up approach for the synthesis of highly ordered fullerene-intercalated graphene hybrids

    Directory of Open Access Journals (Sweden)

    Dimitrios eGournis

    2015-02-01

    Full Text Available Much of the research effort on graphene focuses on its use as a building block for the development of new hybrid nanostructures with well-defined dimensions and properties suitable for applications such as gas storage, heterogeneous catalysis, gas/liquid separations, nanosensing and biomedicine. Towards this aim, here we describe a new bottom-up approach, which combines self-assembly with the Langmuir Schaefer deposition technique to synthesize graphene-based layered hybrid materials hosting fullerene molecules within the interlayer space. Our film preparation consists in a bottom-up layer-by-layer process that proceeds via the formation of a hybrid organo-graphene oxide Langmuir film. The structure and composition of these hybrid fullerene-containing thin multilayers deposited on hydrophobic substrates were characterized by a combination of X-ray diffraction, Raman and X-ray photoelectron spectroscopies, atomic force microscopy and conductivity measurements. The latter revealed that the presence of C60 within the interlayer spacing leads to an increase in electrical conductivity of the hybrid material as compared to the organo-graphene matrix alone.

  9. Controlling benthic release of phosphorus in different Baltic Sea scales

    DEFF Research Database (Denmark)

    Pitkänen, Heikki; Bendtsen, Jørgen; Hansen, Jørgen L. S.;

    The general aim of the PROPPEN project was to study whether it is possible to counteract near-bottom anoxia and excess benthic nutrient release ("internal loading") in the Baltic Sea by artificial oxygenation in cost-efficient and socio-economically beneficial ways. Two pilot sites were selected ...... to counteract anoxia and benthic release of nutrients in coastal marine conditions in the Baltic Sea. The project undertook monitoring of the pilot tests, modelling of effects at different scales, risk management, cost effectiveness and cost benefit analysis....

  10. Top-down and bottom-up regulation of macroalgal community structure on a Kenyan reef

    Science.gov (United States)

    Mörk, Erik; Sjöö, Gustaf Lilliesköld; Kautsky, Nils; McClanahan, Tim R.

    2009-09-01

    Top-down and bottom-up regulation in the form of grazing by herbivores and nutrient availability are important factors governing macroalgal communities in the coral reef ecosystem. Today, anthropogenic activities, such as over-harvesting of herbivorous fish and sea urchins and increased nutrient loading, are altering the interaction of these two structuring forces. The present study was conducted in Kenya and investigates the relative importance of herbivory and nutrient loading on macroalgal community dynamics, by looking at alterations in macroalgal functional groups, species diversity ( H') and biomass within experimental quadrats. The experiment was conducted in situ for 42 days during the dry season. Cages excluding large herbivorous fish and sea urchins were used in the study and nutrient addition was conducted using coated, slow-release fertilizer (nitrogen and phosphorous) at a site where herbivory is generally low and nutrient levels are relatively high for the region. Nutrient addition increased tissue nutrient content in the algae, and fertilized quadrats had 24% higher species diversity. Herbivore exclusion resulted in a 77% increase in algal biomass, mainly attributable to a >1000% increase in corticated forms. These results are in accordance with similar studies in other regions, but are unique in that they indicate that, even when prevailing nutrient levels are relatively high and herbivore pressure is relatively low, continued anthropogenic disturbance results in further ecological responses and increased reef degradation.

  11. The Organizational and Operational Boundaries of Triple Bottom Line Reporting: A Survey

    Science.gov (United States)

    Archel, Pablo; Fernández, Manuel; Larrinaga, Carlos

    2008-01-01

    This article responds to Gray’s (2002) call for normative research on social and environmental accounting (SEA) and Parker’s (2005) call for active engagement in the process of designing SEA systems. More specifically, our investigation focuses on the study of boundary setting for triple bottom line (TBL) reporting, an issue that has been given more attention by practitioners than by researchers. The study reviews the consequences of boundary setting for the discharge of organizational accountability, from which it develops a framework to investigate TBL reporting boundaries and then reports on an empirical survey of best practice. It concludes that organizations are strategically setting and disclosing their boundaries instead of discharging their accountability and argues that such strategies have far-reaching consequences, because reporting boundaries are not only reflective of organizations but also have a constitutive role in their definition. A further consequence is that it calls into question the use of voluntary labeling, such as “in accordance” with Global Reporting Initiative; one implication being that further research into technical developments in TBL reporting could contribute to the discharge of organizational accountability.

  12. Analysis of Interannual Variations of Inorganic Nitrogen in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    Shi Qiang; Gao Zhenhui; Yang Jianqiang

    2002-01-01

    According to the Bohai Sea cross-section data during 1985~1998, the high concentration inorganic nitrogen in the Bohai Sea section bottom layer water nearshore diffused and transferred to the middle of the Bohai Sea year after year. The interannual variations of the concentration of inorganic nitrogen in the Bohai Sea section bottom layer water may reflect the degree of eutrophication more steadily. The nitrate nitrogen and nitrite nitrogen are used to show quasi-equilibrium state interannual variations, but with the aggravation of seawater pollution, the quasi-equilibrium state of interannual variations has been broken and the marine biological-chemical processes can only maintain the secondary part of the interannual variations in a quasi-equilibrium state, but are not sufficient to prevent the main pan of interannual variations from deviating from the quasi-equilibrium state. The spatial distributions of inorganic nitrogen would be affected by the reproduction and swarming of marine life.

  13. Vector-like bottom quarks in composite Higgs models

    International Nuclear Information System (INIS)

    Like many other models, Composite Higgs Models feature the existence of heavy vector-like quarks. Mixing effects between the Standard Model fields and the heavy states, which can be quite large in case of the top quark, imply deviations from the SM. In this work we investigate the possibility of heavy bottom partners. We show that they can have a significant impact on electroweak precision observables and the current Higgs results if there is a sizeable mixing with the bottom quark. We explicitly check that the constraints from the measurement of the CKM matrix element Vtb are fulfilled, and we test the compatibility with the electroweak precision observables. In particular we evaluate the constraint from the Z coupling to left-handed bottom quarks. General formulae have been derived which include the effects of new bottom partners in the loop corrections to this coupling and which can be applied to other models with similar particle content. Furthermore, the constraints from direct searches for heavy states at the LHC and from the Higgs search results have been included in our analysis. The best agreement with all the considered constraints is achieved for medium to large compositeness of the left-handed top and bottom quarks

  14. Stability of leadership in bottom-up hierarchical organizations

    CERN Document Server

    Galam, S

    2007-01-01

    The stability of a leadership against a growing internal opposition is studied in bottom-up hierarchical organizations. Using a very simple model with bottom-up majority rule voting, the dynamics of power distribution at the various hierarchical levels is calculated within a probabilistic framework. Given a leadership at the top, the opposition weight from the hierarchy bottom is shown to fall off quickly while climbing up the hierarchy. It reaches zero after only a few hierarchical levels. Indeed the voting process is found to obey a threshold dynamics with a deterministic top outcome. Accordingly the leadership may stay stable against very large amplitude increases in the opposition at the bottom level. An opposition can thus grow steadily from few percent up to seventy seven percent with not one a single change at the elected top level. However and in contrast, from one election to another, in the vicinity of the threshold, less than a one percent additional shift at the bottom level can drive a drastic an...

  15. Passive Seismic Reflectivity Imaging with Ocean-Bottom Cable Data

    Science.gov (United States)

    Hohl, D.; Mateeva, A.

    2005-12-01

    The idea of imaging the subsurface reflectivity distribution by correlating long traces of seismic ``noise'' (i.e. seismic data recorded without active sources) goes back more than 30 years [1]. To this day, passive seismic reflectivity imaging has not been exploited for business use in the E&P industry. The conditions for successful passive seismic reflection imaging have greatly improved over the past few years, and the prize of cheap continuous sourceless seismic imaging and possibly monitoring is still large. Nearly unlimited quantities of very high quality passive noise data are now available from permanent 4C ocean bottom cable (OBC) installations. In the present contribution, we report our initial results for single-line (2D) OBC data collected in the North Sea and GOM. The OBCs used for the experiment are of length 6-10 km with 4C receivers spaced 50 m apart. They are deployed in both shallow and deep water over large hydrocarbon reservoirs. Passive noise data were recorded for 8-24 h periods, sometimes several times, and months apart. In the analysis presented here only the hydrophone records are used, and the data from all recording periods are used together to produce a single 2D migrated reflectivity section. We observe that environmental noise (e.g. boat and rig activity) play an important role for imaging and usually requires pre-migration seismic processing steps to filter out unwanted signals. At the core of our image generation and processing sequence is the crosscorrelation of noise trace pairs and subsequent prestack time migration [1] with a velocity model established for the active-source OBC data processing. We compute 4 sec of lag time to either side of t=0. After removing unwanted signals (e.g. seafloor interface waves) from these ``virtual shot gathers'' one can clearly detect the linear-moveout direct water wave with velocity 1500 m/s, and a linear interface wave with velocity 2000 m/s. Other ``events'' with moveout are visible, but the

  16. Constraints on Lithospheric Dynamics From Curie Depth/Magnetic Bottom Depth Determinations

    Science.gov (United States)

    Ravat, D.

    2011-12-01

    In Eastern Egypt and parts of Canada, where inferred mantle temperatures are cooler than the Curie temperature of magnetite, several carefully performed spectral magnetic bottom estimates correspond to the Moho. This suggests that the continental mantle in these regions is likely to be non-magnetic and constitutes the magnetic anomaly based validation of the proposal of Wasilewski and co-workers that the Moho is a magnetic boundary. On the other hand, a few estimates of magnetic bottom in the Red Sea reside in the oceanic lithospheric uppermost mantle suggesting that serpentinization may have occurred there and hence that part of the mantle may be magnetic. It remains to be seen whether normal uppermost oceanic mantle in many places around the world is serpentinized. A tectonic scenario where the process of serpentinization may be important is the mantle wedges above subducting oceanic plates. I use carefully derived Curie depth/magnetic bottom estimates over the North American continent to explore whether ancient, presently intracratonic, subduction margins can be detected where the upper plate mantle may have been serpentinized. In this context, evaluation of ensemble, parallelepiped, and fractal magnetization models and methods for performing magnetic depth calculations suggests that there are many solutions that fit the same observed azimuthally averaged spectra and, therefore, finding solutions on the criterion of the best-fit spectra alone does not guarantee the most optimum solution. Derived solutions must be validated by different magnetic bottom determining methods and through complementary geophysical information before they can be meaningfully interpreted. Using layered magnetization structure from these methods, I also derive an upper limit for the regional magnetization for the bottommost layer. In the regions of Pikwitonei and Kapuskasing uplifted lower crustal cross-sections in Canada, where magnetization was previously thought to be inadequate to

  17. Transfer of radionuclides from high polluted bottom sediments to marine organisms through benthic food chain in post Fukushima period

    Science.gov (United States)

    Bezhenar, Roman; Jung, Kyung Tae; Maderich, Vladimir; Willemsen, Stefan; de With, Govert; Qiao, Fangli

    2015-04-01

    accumulates in a specific tissue called target tissue. This tissue (bone, flesh, stomach, and organs) controls the overall elimination rate of the nuclide in the organism. The model prediction for the coastal area around the FDNPP agree well with observations. In addition the effects from the Chernobyl accident on the Baltic Sea are modelled and these results also are in good agreement with available data. These results demonstrate the importance of the benthic food chain in long-term transfer of radionuclides from high polluted bottom sediments to the marine organisms. The developed model can be applied for different regions of the World Ocean.

  18. Development of a coastal upwelling front driven by advection and topographic effects in the North Sea-Baltic Sea transition

    OpenAIRE

    Lund-hansen, Lc; Vang, T

    2003-01-01

    Upwelling of cold. saline, and nutrient rich water was observed in late September 1999 along an east-west transect in the SW Kattegat. The Kattegat forms part of the transitional zone between the high saline North Sea and the low saline Baltic Sea. The upwelling occurred after an extended period of northward flow and eastern winds in the Kattegat, that changed into a southward flow as wind ceased. The upwelling was the result of a combination of high current speeds and bottom topography where...

  19. Nanofabrication of SERS Substrates for Single/Few Molecules Detection

    KAUST Repository

    Melino, Gianluca

    2015-05-04

    Raman spectroscopy is among the most widely employed methods to investigate the properties of materials in several fields of study. Evolution in materials science allowed us to fabricate suitable substrates, at the nanoscale, capable to enhance the electromagnetic field of the signals coming from the samples which at this range turn out to be in most cases singles or a few molecules. This particular variation of the classical technique is called SERS (Surface Enanched Raman Spectroscopy). In this work, the enhancement of the electromagnetic field is obtained by manipulation of the optical properties of metals with respect to their size. By using electroless deposition (bottom up technique), gold and silver nanoparticles were deposited in nanostructured patterns obtained on silicon wafers by means of electron beam lithography (top down technique). Rhodamine 6G in aqueous solution at extremely low concentration (10-8 M) was absorbed on the resultant dimers and the collection of the Raman spectra demonstrated the high efficiency of the substrates.

  20. Sea-surface and deep-magnetic data at Vavilov Seamount, Tyrrhenian Sea

    Science.gov (United States)

    Muccini, Filippo; Cocchi, Luca; Locritani, Marina; Carmisciano, Cosmo

    2016-04-01

    Sea surface and deep magnetic data were acquired at Vavilov seamount, in the Tyrrhenian sea. Vavilov seamount is located in the central portion of the homonymous Vavilov basin. The seamount stands about 2800 meters above the seafloor at 3600 meters depth, with the top at about 800 meters below the sea level. Oceanization of the basin occurred during the Late Miocene-Early Pliocene. The magnetic data were collected in 2011 on board the Nave Ammiraglio Magnaghi by using a Marine Magnetics Seaspy magnetometer. The sea surface magnetic survey was realized with two different grids: the first regional one, with 13 parallel lines about 43 Km long, 3 Km spaced (104° N oriented) and 6 tie control lines about 40 Km long, 5 Km spaced (014° N oriented). The second one was realized to better define the volcanic structure of the seamount, and was achieved by acquiring 12 magnetic parallel lines (104° N), 18 Km long and 1 Km spaced. The deep magnetic data were collected by towing a magnetic sensor coupled with a L3 sidescan sonar Klein 3000. A set of 5 parallel lines were acquired in correspondence of the bathymetric top of the seamount with the sensor flying at about constant depth of 700 meters. These data represents the first near-bottom magnetic data collected for Vavilov seamount and it allows comparison between sea-surface and deep magnetic data.

  1. Bottom-Up Nano-heteroepitaxy of Wafer-Scale Semipolar GaN on (001) Si

    KAUST Repository

    Hus, Jui Wei

    2015-07-15

    Semipolar {101¯1} InGaN quantum wells are grown on (001) Si substrates with an Al-free buffer and wafer-scale uniformity. The novel structure is achieved by a bottom-up nano-heteroepitaxy employing self-organized ZnO nanorods as the strain-relieving layer. This ZnO nanostructure unlocks the problems encountered by the conventional AlN-based buffer, which grows slowly and contaminates the growth chamber. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Raman mapping investigation of single-walled carbon nanotube bending in bottom-contact field-effect-transistor devices

    Science.gov (United States)

    Setiadi, Agung; Akai-Kasaya, Megumi; Kuwahara, Yuji

    2016-09-01

    We investigated the bending of single-walled carbon nanotubes (SWNTs) in bottom-contact SWNT devices using Raman mapping measurements. The height difference between the metal electrodes and the substrate caused the SWNTs to bend, down-shifting the G+ and G- bands of the bent SWNTs. No shifting of the G+ and G- bands was observed when flat electrodes were used. Shifting of the G+ and G- bands in SWNTs is strongly correlated to modulation of the Fermi level. We confirmed this effect by measuring the transport properties of the SWNT devices, which were in good agreement with the Raman measurement results.

  3. Exploring the Microseismicity of the Gakkel Ridge from Arctic Sea Ice

    OpenAIRE

    Hope, Gaute

    2013-01-01

    Monitoring of microseismicity is an important tool to understand the magmatism, tectonics and hydrothermal circulation of a mid-oceanic ridge. In the presence of sea ice, use of ocean bottom seismometers is not practical, but several experiments with small networks of seismometers drifting with the sea ice have previously been completed successfully. The goal of this project was to build on the earlier experiments and develop a method for monitoring the microseismicity above the Gakkel Ri...

  4. Advances in Studying Oceanic Circulation from Hydrographic Data with Applications in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    王桂华; 李荣凤; 闫长香

    2003-01-01

    Methods for studying oceanic circulation from hydrographic data are reviewed in the context of their applications in the South China Sea. These methods can be classified into three types according to their different dynamics as follows: (1) descriptive methods, (2) diagnostic methods without surface and bottom forcing, and (3) diagnostic methods with the above boundary forcing. The paper discusses the progress made in the above methods together with the advancement of study in the South China Sea circulation.

  5. Distribution of skates and sharks in the North Sea:112 years of change

    OpenAIRE

    Sguotti, Camilla; Lynam, Christopher P.; Garcia-Carreras, Bernardo; Ellis, Jim R.; Engelhard, Georg

    2016-01-01

    How have North Sea skate and shark assemblages changed since the early 20th century when bottom trawling became widespread, whilst their environment became increasingly impacted by fishing, climate change, habitat degradation and other anthropogenic pressures? This article examines long-term changes in the distribution and occurrence of the elasmobranch assemblage of the southern North Sea, based on extensive historical time series (1902–2013) of fishery-independent survey data. In general, l...

  6. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

    Science.gov (United States)

    Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

    2016-08-01

    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

  7. Aral Sea basin: a sea dies, a sea also rises.

    Science.gov (United States)

    Glantz, Michael H

    2007-06-01

    The thesis of this article is quite different from many other theses of papers, books, and articles on the Aral Sea. It is meant to purposely highlight the reality of the situation in Central Asia: the Aral Sea that was once a thriving body of water is no more. That sea is dead. What does exist in its place are the Aral seas: there are in essence three bodies of water, one of which is being purposefully restored and its level is rising (the Little Aral), and two others which are still marginally connected, although they continue to decline in level (the Big Aral West and the Big Aral East). In 1960 the level of the sea was about 53 m above sea level. By 2006 the level had dropped by 23 m to 30 m above sea level. This was not a scenario generated by a computer model. It was a process of environmental degradation played out in real life in a matter of a few decades, primarily as a result of human activities. Despite wishes and words to the contrary, it will take a heroic global effort to save what remains of the Big Aral. It would also take a significant degree of sacrifice by people and governments in the region to restore the Big Aral to an acceptable level, given that the annual rate of flow reaching the Amudarya River delta is less than a 10th of what it was several decades ago. Conferring World Heritage status to the Aral Sea(s) could spark restoration efforts for the Big Aral. PMID:17626470

  8. Perspectives on Geoacoustic Inversion of Ocean Bottom Reflectivity Data

    Directory of Open Access Journals (Sweden)

    N. Ross Chapman

    2016-09-01

    Full Text Available This paper focuses on acoustic reflectivity of the ocean bottom, and describes inversion of reflection data from an experiment designed to study the physical properties and structure of the ocean bottom. The formalism of Bayesian inference is reviewed briefly to establish an understanding of the approach for inversion that is in widespread use. A Bayesian inversion of ocean bottom reflection coefficient versus angle data to estimate geoacoustic model parameters of young oceanic crust is presented. The data were obtained in an experiment to study the variation of sound speed in crustal basalt with age of the crust at deep water sites in the Pacific Ocean where the sediment deposits overlying the basalt are very thin. The inversion results show that sound speed of both compressional and shear waves is increasing with crustal age over the track of the experiment where age increased from 40 to 70 million years.

  9. Bottom quark contribution to spin-dependent dark matter detection

    Directory of Open Access Journals (Sweden)

    Jinmian Li

    2016-05-01

    Full Text Available We investigate a previously overlooked bottom quark contribution to the spin-dependent cross section for Dark Matter (DM scattering from the nucleon. While the mechanism is relevant to any supersymmetric extension of the Standard Model, for illustrative purposes we explore the consequences within the framework of the Minimal Supersymmetric Standard Model (MSSM. We study two cases, namely those where the DM is predominantly Gaugino or Higgsino. In both cases, there is a substantial, viable region in parameter space (mb˜−mχ≲O(100 GeV in which the bottom contribution becomes important. We show that a relatively large contribution from the bottom quark is consistent with constraints from spin-independent DM searches, as well as some incidental model dependent constraints.

  10. Steam bottoming cycle for an adiabatic diesel engine

    Science.gov (United States)

    Poulin, E.; Demier, R.; Krepchin, I.; Walker, D.

    1984-01-01

    Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated.

  11. Bottom Production in Two-Photon Collisions at LEP

    CERN Document Server

    Böhrer, A

    2001-01-01

    Results on inclusive and exclusive bottom production in gammagamma collisions are presented. The total cross section of inclusive bottom production is investigated through its leptonic decays at LEP II energies by the experiments L3 and OPAL. The average cross section, after correction for acceptances and efficiencies, is sigma_tot = 13.3 +- 1.5 +- 2.3 pb. The next-to-leading order calculations are lower than the data by a factor three, which corresponds to a difference of more than three standard deviations. ALEPH studied the exclusive bottom production. Searching for the eta_b one candidate is found. Limits on Gamma_gammagamma(eta_b)*BR for 4 and 6 charged particles are extracted. The candidate has a mass of 9.30 +- 0.04 GeV.

  12. OIL DECONTAMINATION OF BOTTOM SEDIMENTS EXPERIMENTAL WORK RESULTS

    Directory of Open Access Journals (Sweden)

    Lushnikov Sergey V.

    2006-08-01

    Full Text Available This article presents the results of experimental work during 2004-2005 on oil decontamination of bottom sediments of Lake Schuchye, situated in the Komi Republic (Northern Russia. The cause of thecontamination were huge oil spills occurred after a series of accidental ruptures on the Harjaga-Usinsk and Vozej-Usinsk oil-pipe lines in 1994. Flotation technology was used for the cleaning of bottom sediments.157 tons of crude oil were removed during the course of 2-year experimental work from an area of 4,1 ha.The content of aliphatic and alicyclic oil hydrocarbons was reduced from 53,3 g/kg to 2,2 g/kg, on average.Hydrobiological investigations revealed that bottom sediments started to be inhabited by benthos organisms, dominantly Oligochaeta. Besides Oligochaeta, Chironomidae maggots and Bivalvia were detected. Theappearance of Macrozoobenthos organisms can serve as a bioindicator of water quality.

  13. Fluid flow over arbitrary bottom topography in a channel

    Science.gov (United States)

    Panda, Srikumar

    2016-05-01

    In this paper, two-dimensional free surface potential flow over an arbitrary bottom in a channel is considered to analyze the behavior of the free surface profile using linear theory. It is assumed that the fluid is inviscid, incompressible and flow is irrotational. Perturbation analysis in conjunction with Fourier transform technique is employed to determine the first order corrections of some important physical quantities such as free surface profile, velocity potential, etc. From the practical point of view, one arbitrary bottom topography is considered to determine the free surface profile since the free surface profile depends on the bottom topography. It is found that the free surface profile is oscillatory in nature, representing a wave propagating downstream and no wave upstream.

  14. 7 CFR 1437.310 - Sea grass and sea oats.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  15. Quantifying the importance of sediment resuspension for the North Sea and Baltic Sea ecosystem

    Science.gov (United States)

    Nissen, Cara; Schrum, Corinna; Daewel, Ute; Fennel, Katja; Castaño Primo, Rocío

    2014-05-01

    Including sedimentary processes such as resuspension in marine coupled bio-physical models is crucial to realistically simulate the dynamics of biologically important chemical variables (e.g oxygen and the macro-nutrients nitrate, phosphate and silicate). These comprise diffusive release of dissolved nutrients and resuspension of particulate organic material, which occurs when a critical bottom shear stress (τcrit) acting on the sediment particles is exceeded. In global and regional modelling approaches sediment-water exchange is often parametrized by sedimentation and constant release rates and dynamic resuspension resolving the tidal cycle is often neglected in coupled physical-biological ecosystem models. During resuspension, sediment particles get transported back into the water column. Thereby, both the turbidity of the water and nutrient availability by releasing dissolved nutrients from the pore-water are changed. Since both light and nutrients are limiting factors in primary production, it is near by hand to suspect resuspension to play an important role in the growth of phytoplankton. Here, we assess the role of resuspension and its dynamic consideration for the modelled productivity and CO2 air-sea exchange in the North Sea and Baltic Sea using the coupled 3D physical-biological model ECOSMO. ECOSMO is a coupled hydrodynamic-sea ice-NPZD-carbonate-system model and is implemented for the North Sea and Baltic Sea. Its ecosystem module includes interactions between three functional groups of phytoplankton, two of zooplankton, detritus, oxygen, three nutrient cycles (nitrogen, phosphorus, silicate) and sediment pools. In the North Sea, wind forcing and strong tides lead to a frequent exceedance of the critical bottom shear stress and therefore, resuspension events take place regularly, especially in the shallow coastal areas where the tidal range is largest. Here, the model results indicate a clear increase in estimated primary production when dynamical

  16. Sea Lion Diet Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions...

  17. Sea Turtle Interaction Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Interaction Report is a report sent out in pdf format to authorized individuals that summarizes sea turtle interactions in the longline fishery. The...

  18. PLZT capacitor on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, Manuel Ray; Taylor, Ralph S.; Berlin, Carl W.; Wong, Celine Wk; Ma, Beihai; Balachandran, Uthamalingam

    2016-03-29

    A lead-lanthanum-zirconium-titanate (PLZT) capacitor on a substrate formed of glass. The first metallization layer is deposited on a top side of the substrate to form a first electrode. The dielectric layer of PLZT is deposited over the first metallization layer. The second metallization layer deposited over the dielectric layer to form a second electrode. The glass substrate is advantageous as glass is compatible with an annealing process used to form the capacitor.

  19. The Interplay of Top-Down and Bottom-Up

    DEFF Research Database (Denmark)

    Winkler, Till; Brown, Carol V.; Ozturk, Pinar

    2014-01-01

    The exchange of patient health information across different organizations involved in healthcare delivery has potential benefits for a wide range of stakeholders. However, many governments in Europe and in the U.S. have, despite both top-down and bottom-up initiatives, experienced major barriers...... organizations (HIOs) that facilitate HIE across regional stakeholders remains an unanswered question. This research investigates the impacts of top-down and bottom-up initiatives on the evolutionary paths of HIOs in two contingent states in the U.S. (New Jersey and New York) which had different starting...

  20. Discovering the Higgs Bosons of Minimal Supersymmetry with Bottom Quarks

    CERN Document Server

    Kao, Chung; Sayre, Joshua; Wang, Yili

    2009-01-01

    We investigate the prospects for the discovery of a neutral Higgs boson produced with one bottom quark followed by Higgs decay into a pair of bottom quarks at the CERN Large Hadron Collider (LHC) and the Fermilab Tevatron Collider. We work within the framework of the minimal supersymmetric standard model. The dominant physics background is calculated with realistic acceptance cuts and efficiencies including the production of $bb\\bar{b}$, $\\bar{b}b\\bar{b}$, $jb\\bar{b}$ ($j = g, q, \\bar{q}$; $q = u, d, s, c$), $t\\bar{t} \\to b\\bar{b}jj\\ell\

  1. On the universal sl_2 invariant of Brunnian bottom tangles

    CERN Document Server

    Suzuki, Sakie

    2011-01-01

    A link L is called Brunnian if every proper sublink of L is trivial. Similarly, a bottom tangle T is called Brunnian if every proper subtangle of T is trivial. In this paper, we give a small subalgebra of the n-fold completed tensor power of U_h(sl_2) in which the universal sl_2 invariant of n-component Brunnian bottom tangles takes values. As an application, we give a divisibility property of the colored Jones polynomial of Brunnian links.

  2. On the universal sl_2 invariant of boundary bottom tangles

    CERN Document Server

    Suzuki, Sakie

    2011-01-01

    The universal sl_2 invariant of bottom tangles has a universality property for the colored Jones polynomial of links. Habiro conjectured that the universal sl_2 invariant of boundary bottom tangles takes values in certain subalgebras of the completed tensor powers of the quantized enveloping algebra U_h(sl_2) of the Lie algebra sl_2. In the present paper, we prove an improved version of Habiro's conjecture. As an application, we prove a divisibility property of the colored Jones polynomial of boundary links.

  3. 30 Gbps bottom-emitting 1060 nm VCSEL

    DEFF Research Database (Denmark)

    Tatarczak, Anna; Zheng, Y.; Rodes, G. A.;

    2014-01-01

    1060 nm VCSEL-based data transmission over 50 m OM3 MMF at 30 Gbit/s is experimentally demonstrated. A highly-strained bottom-emitting QW VCSEL with p-type modulation doping is used with 3.77 mA bias and 0.55 V data amplitude.......1060 nm VCSEL-based data transmission over 50 m OM3 MMF at 30 Gbit/s is experimentally demonstrated. A highly-strained bottom-emitting QW VCSEL with p-type modulation doping is used with 3.77 mA bias and 0.55 V data amplitude....

  4. Thickness optimization of the flow plate of bottom end piece

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jeong Sik; Lee, Jae Kyung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-05-01

    High burnup fuel assembly has been the worldwide trends in nuclear fuel design. The burnup increase will result in more axial irradiation growth of fuel rod and consequently it requires more space between top and bottom nozzles to accommodate the increased axial growth of the fuel rod. In order to get more axial space between top and bottom nozzles, thickness optimization of the flow plate for the Korean fuel assembly (KOFA) as well as DRBEP-DG based on stress criterion was performed by way of finite element code `ANSYS`. 12 tabs., 92 figs., 9 refs. (Author) .new.

  5. Pedestal substrate for coated optics

    Science.gov (United States)

    Hale, Layton C.; Malsbury, Terry N.; Patterson, Steven R.

    2001-01-01

    A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disk-like optic or substrate section having a top surface that is coated, a disk-like base section that provides location at which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disk-like base can be formed separately and connected to the connecting section. By way of example, the pedestal optical substrate may be utilized in the fabrication of optics for an extreme ultraviolet (EUV) lithography imaging system, or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

  6. Holocene ice dynamics and bottom-water formation associated with Cape Darnley polynya activity recorded in Burton Basin, East Antarctica

    Science.gov (United States)

    Borchers, Andreas; Dietze, Elisabeth; Kuhn, Gerhard; Esper, Oliver; Voigt, Ines; Hartmann, Kai; Diekmann, Bernhard

    2016-03-01

    A multi-proxy study including sedimentological, mineralogical, biogeochemical and micropaleontological methods was conducted on sediment core PS69/849-2 retrieved from Burton Basin, MacRobertson Shelf, East Antarctica. The goal of this study was to depict the deglacial and Holocene environmental history of the MacRobertson Land-Prydz Bay region. A special focus was put on the timing of ice-sheet retreat and the variability of bottom-water formation due to sea ice formation through the Holocene. Results from site PS69/849-2 provide the first paleo-environmental record of Holocene variations in bottom-water production probably associated to the Cape Darnley polynya, which is the second largest polynya in the Antarctic. Methods included end-member modeling of laser-derived high-resolution grain size data to reconstruct the depositional regimes and bottom-water activity. The provenance of current-derived and ice-transported material was reconstructed using clay-mineral and heavy-mineral analysis. Conclusions on biogenic production were drawn by determination of biogenic opal and total organic carbon. It was found that the ice shelf front started to retreat from the site around 12.8 ka BP. This coincides with results from other records in Prydz Bay and suggests warming during the early Holocene optimum next to global sea level rise as the main trigger. Ice-rafted debris was then supplied to the site until 5.5 cal. ka BP, when Holocene global sea level rise stabilized and glacial isostatic rebound on MacRobertson Land commenced. Throughout the Holocene, three episodes of enhanced bottom-water activity probably due to elevated brine rejection in Cape Darnley polynya occured between 11.5 and 9 cal. ka BP, 5.6 and 4.5 cal. ka BP and since 1.5 cal. ka BP. These periods are related to shifts from warmer to cooler conditions at the end of Holocene warm periods, in particular the early Holocene optimum, the mid-Holocene warm period and at the beginning of the neoglacial. In

  7. Vertical Mixing in the Dead Sea

    Science.gov (United States)

    Gertman, Isaac; Ozer, Tal; Katsenelson, Boris; Lensky, Nadav

    2015-04-01

    For hundreds of years, the Dead Sea was characterized by a stable haline stratification, supported by runoff. The penetration of the winter convection was limited to an upper mixed layer (UML) of about 30-50 m. Below the UML, a stable halocline prevented the mixing. As a result of the runoff reduction, the UML salinity increased and the gravitational stability diminished. During the winter of 1978-1979, the sea water overturned, ending the long-term stable hydrological regime. Since 1979, the haline stratification structure reoccurred twice after extremely rainy winters, in 1980-82 and 1992-1995. In other years, the sea was entirely mixed by winter thermal convection ( which occurs from November to March ) and had a seasonal pycnocline beneath the UML during summer. Profiles of temperature and quasi-salinity (density anomaly from 1000 kg/m3 for the chosen reference temperature of 32° C) during the last 19 years, show the formation of summer ``overturning halocline'' beneath the UML, and the thermocline that supports the stable stratification. Another warm and saline layer is formed also during the summer period near the bottom. This layer spreads from the southern part of the sea, where end-brine is discharged to the sea from the Israeli and Jordanian salt plants' evaporation ponds. The end-brine has extremely high salinity (˜ 350 g/kg) and, in spite of the high temperatures ( ˜ 45° C), high density (1350 kg/m^3), it therefore spreads as a gravitational current in the Dead Sea deep basin. Estimation of the density ratio (Rρ) for the Dead Sea water (where measurements of water salinity is quite difficult) was done using quasi-salinity (σ32) and potential temperature (θ): Rρ= [α(partialθ/partial z)]/[β(partial σ32/partial z)], where α and β are temperature expansion and quasi-salinity contraction coefficients respectively. The values of α and β for the Dead Sea water were defined from water samples collected during 2008. The Rρ values confirm that

  8. The coherence of small island sea-level with the wider ocean: a model study

    Directory of Open Access Journals (Sweden)

    Joanne Williams

    2012-09-01

    Full Text Available Studies comparing tide gauge measurements with sea level from nearby satellite altimetry have shown good agreement for some islands, and poor agreement for others, though no explanation has been offered. Using the 1/12° OCCAM ocean model, we investigate the relationship between sea level at small, open-ocean islands, and offshore sea level. For every such island or seamount in the model, we compare the shallow-water sea level with the steric and bottom pressure variability in a neighboring ring of deep water. We find a latitude-dependent range of frequencies for which off-shore sea level is poorly correlated with island sea level. This poor coherence occurs in a spectral region for which steric signals dominate, but are unable to propagate as baroclinic Rossby waves. This mode of decoupling does not arise because of island topography, as the same decoupling is seen between deep ocean points and surrounding rings.

  9. First record of the moray eel Gymnothorax reticularis, Bloch, 1795 in the Mediterranean Sea, with a note on its taxonomy and distribution.

    Science.gov (United States)

    Stern, Nir; Goren, Menachem

    2013-01-01

    The first Red-Sea Indo-Pacific alien moray eel in the Eastern Mediterranean is reported here. A single specimen ot Gymnothorax reticularis was captured by a commercial bottom-trawl vessel off the northern coast of Israel. Morphological and anatomical similarities with the single known Red-Sea specimen raise an old taxonomic dilemma.

  10. SERS substrate and a method of providing a SERS substrate

    DEFF Research Database (Denmark)

    2011-01-01

    Source: US2011116089A A substrate primarily for SERS determination, the substrate has a number of elongate elements with a density of at least 1x108 elongate elements per cm2 and having metal coated tips. When the elements may be made to lean toward each other, such as by providing a drop...

  11. New perspectives in benthic deep-sea microbial ecology

    Directory of Open Access Journals (Sweden)

    Cinzia eCorinaldesi

    2015-03-01

    Full Text Available Deep-sea ecosystems represent the largest and most remote biome of the biosphere. They play a fundamental role in global biogeochemical cycles and their functions allow existence of life on our planet. In the last 20 years enormous progress has been made in the investigation of deep-sea microbes, but the knowledge of the microbial ecology of the soft bottoms (representing >90% of the deep-sea floor surface is still very limited. Deep-sea sediments host the largest fractions of Bacteria, Archaea and viruses on Earth, and potentially, a high diversity. At the same time, available results from metagenomics suggest that a large fraction of microbial taxa is completely unknown to science. Estimating the diversity of deep-sea benthic microbes and understanding their functions are some of the challenges of absolute priority, not only for deep-sea microbial ecology, but also for the entire research field of life sciences. The achievement of these goals, given the importance of the deep-sea microbial life for the functioning of the global biosphere, will open new perspectives for the comprehension of adaptation processes to the impact of global changes.

  12. Sea level rise

    OpenAIRE

    Warrick, R. A.; Oerlemans, J.

    1990-01-01

    This Section addresses three questions: Has global-mean sea level been rising during the last 100 years? What are the causal factors that could explain a past rise in sea level? And what increases in sea level can be expected in the future?

  13. Extreme Longevity in Proteinaceous Deep-Sea Corals

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Dunbar, R B; Fallon, S J; Mucciarone, D A

    2009-02-09

    Deep-sea corals are found on hard substrates on seamounts and continental margins world-wide at depths of 300 to {approx}3000 meters. Deep-sea coral communities are hotspots of deep ocean biomass and biodiversity, providing critical habitat for fish and invertebrates. Newly applied radiocarbon age date from the deep water proteinaceous corals Gerardia sp. and Leiopathes glaberrima show that radial growth rates are as low as 4 to 35 {micro}m yr{sup -1} and that individual colony longevities are on the order of thousands of years. The management and conservation of deep sea coral communities is challenged by their commercial harvest for the jewelry trade and damage caused by deep water fishing practices. In light of their unusual longevity, a better understanding of deep sea coral ecology and their interrelationships with associated benthic communities is needed to inform coherent international conservation strategies for these important deep-sea ecosystems.

  14. Effects of time and duration of rearing with bottom sand on the occurrence and expansion of staining-type hypermelanosis in the Japanese flounder Paralichthys olivaceus

    OpenAIRE

    Isojima, Toshinori; Makino, Naoshi; Miyama, Yoshifumi; Tagawa, Masatomo

    2014-01-01

    We previously reported that the progression of staining-type hypermelanosis spontaneously ceased at a specific time and area in Japanese flounder Paralichthys olivaceus. To examine whether time is a limiting factor in the spontaneous cessation of staining, we experimentally controlled the initiation and duration of staining by manipulating the bottom substrate condition in the fish tanks. At 151 days post hatching (DPH; 11 weeks), spontaneous cessation of staining was observed in fish reared ...

  15. Application of adjoint assimilation technique in simulating tides and tidal currents of the Bohai Sea, the Yellow Sea and the East China Sea

    Institute of Scientific and Technical Information of China (English)

    Cheng Yongcun; Lu Xianqing; Liu Yuguang; Xu Qing

    2007-01-01

    Considering the interaction of different tidal waves, an adjoint numerical model is developed to simulate M2, S2, K1 and O1 tidal waves in the Bohai Sea, the Yellow Sea and the East China Sea(B-Y-E) simultaneously. Compared with previous researches, by using the adjoint assimilation technique to inverse open boundary conditions and bottom friction coefficients based on altimetric data from TOPEX/Poseidon (T/P)and tidal gauges data, the precision of the numerical simulation is significantly improved. Selecting 14 days of simulated results after t11e initial warming run to conduct harmonic analysis, the results can show the characteristics of M2, S2, K1 and O1 tidal wave systems perfectly in B-Y-E. Compared with 9 current stations, the calculated harmonic constants of tidal currents for M2 and K1 are in good agreement With the observed ones.

  16. Advantages of flattened electrode in bottom contact single-walled carbon nanotube field-effect transistor

    Energy Technology Data Exchange (ETDEWEB)

    Setiadi, Agung; Akai-Kasaya, Megumi, E-mail: kasaya@prec.eng.osaka-u.ac.jp; Saito, Akira; Kuwahara, Yuji [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 565-0871 Suita (Japan)

    2014-09-01

    We fabricated single-walled carbon nanotube (SWNT) field-effect transistor (FET) devices on flattened electrodes, in which there are no height difference between metal electrodes and the substrate. SWNT-FET fabricated using bottom contact technique have some advantages, such that the SWNTs are free from electron irradiation, have direct contact with the desired metal electrodes, and can be functionalized before or after deposition. However, the SWNTs can be bent at the contact point with the metal electrodes leading to a different electrical characteristic of the devices. The number of SWNT direct junctions in short channel length devices is drastically increased by the use of flattened electrodes due to strong attractive interaction between SWNT and the substrate. The flattened electrodes show a better balance between their hole and electron mobility compared to that of the non-flattened electrodes, that is, ambipolar FET characteristic. It is considered that bending of the SWNTs in the non-flattened electrode devices results in a higher Schottky barrier for the electrons.

  17. Micromorph tandem solar cells: optimization of the microcrystalline silicon bottom cell in a single chamber system

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Dan; Zheng Xin-Xia; Xu Sheng-Zhi; Lin Quan; Wei Chang-Chun; Sun Jian; Geng Xin-Hua; Zhao Ying

    2011-01-01

    We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates.The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO.By controlling boron and phosphorus contaminations,a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm.In tandem devices,by thickness optimization of the microcrystalline silicon bottom solar cell,we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer.In order to enhance the performance of the tandem solar cells,an improved light trapping structure with a ZnO/Al back reflector is used.As a result,a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.

  18. Micromorph tandem solar cells: optimization of the microcrystalline silicon bottom cell in a single chamber system

    Science.gov (United States)

    Zhang, Xiao-Dan; Zheng, Xin-Xia; Xu, Sheng-Zhi; Lin, Quan; Wei, Chang-Chun; Sun, Jian; Geng, Xin-Hua; Zhao, Ying

    2011-10-01

    We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates. The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO. By controlling boron and phosphorus contaminations, a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm. In tandem devices, by thickness optimization of the microcrystalline silicon bottom solar cell, we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer. In order to enhance the performance of the tandem solar cells, an improved light trapping structure with a ZnO/Al back reflector is used. As a result, a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.

  19. Advantages of flattened electrode in bottom contact single-walled carbon nanotube field-effect transistor

    International Nuclear Information System (INIS)

    We fabricated single-walled carbon nanotube (SWNT) field-effect transistor (FET) devices on flattened electrodes, in which there are no height difference between metal electrodes and the substrate. SWNT-FET fabricated using bottom contact technique have some advantages, such that the SWNTs are free from electron irradiation, have direct contact with the desired metal electrodes, and can be functionalized before or after deposition. However, the SWNTs can be bent at the contact point with the metal electrodes leading to a different electrical characteristic of the devices. The number of SWNT direct junctions in short channel length devices is drastically increased by the use of flattened electrodes due to strong attractive interaction between SWNT and the substrate. The flattened electrodes show a better balance between their hole and electron mobility compared to that of the non-flattened electrodes, that is, ambipolar FET characteristic. It is considered that bending of the SWNTs in the non-flattened electrode devices results in a higher Schottky barrier for the electrons.

  20. A Bottom-Up Engineered Broadband Optical Nanoabsorber for Radiometry and Energy Harnessing Applications

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.; Megerian, Krikor G.; Eastwood, Michael; Green, Robert O.; Bandaru, Prabhakar R.

    2013-01-01

    Optical absorbers based on vertically aligned multi-walled carbon nanotubes (MWCNTs), synthesized using electric-field assisted growth, are described here that show an ultra-low reflectance, 100X lower compared to Au-black from wavelength lamba approximately 350 nm - 2.5 micron. A bi-metallic Co/Ti layer was shown to catalyze a high site density of MWCNTs on metallic substrates and the optical properties of the absorbers were engineered by controlling the bottom-up synthesis conditions using dc plasma-enhanced chemical vapor deposition (PECVD). Reflectance measurements on the MWCNT absorbers after heating them in air to 400deg showed negligible changes in reflectance which was still low, approximately 0.022 % at lamba approximately 2 micron. In contrast, the percolated structure of the reference Au-black samples collapsed completely after heating, causing the optical response to degrade at temperatures as low as 200deg. The high optical absorption efficiency of the MWCNT absorbers, synthesized on metallic substrates, over a broad spectral range, coupled with their thermal ruggedness, suggests they have promise in solar energy harnessing applications, as well as thermal detectors for radiometry.