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Sample records for eastern weddell sea

  1. Sea ice ridging in the eastern Weddell Sea

    Science.gov (United States)

    Lytle, V. I.; Ackley, S. F.

    1991-10-01

    In August 1986, sea ice ridge heights and spatial frequency in the eastern Weddell Sea were measured using a ship-based acoustical sounder. Using a minimum ridge sail height of 0.75 m, a total of 933 ridges were measured along a track length of 415 km. The ridge frequency varied from 0.4 to 10.5 ridges km-1. The mean height of the ridges was found to be about 1.1 m regardless of the ridge frequency. These results are compared to other ridging statistics from the Ross Sea and found to be similar. Comparison with Arctic data, however, indicates that the height and frequency of the ridges are considerably less in the Weddell Sea than in the Arctic. Whereas in the Arctic the mean ridge height tends to increase with the ridge frequency, we found that this was not the case in the Weddell Sea, where the mean ridge height remained constant irrespective of the ridge frequency. Estimates of the contribution of deformed ice to the total ice thickness are generally low except for a single 53-km section where the ridge frequency increased by an order of magnitude. This resulted in an increase in the equivalent mean ice thickness due to ridging from 0.04 m in the less deformed areas to 0.45 m in the highly deformed section. These values were found to be consistent with values obtained from drilled profile lines during the same cruise.

  2. Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea

    OpenAIRE

    Gurarie, Eliezer; Bengtson, John L.; Bester, Marthán N.; Blix, Arnoldus Schytte; Cameron, Michael; Bornemann, Horst; Nordøy, Erling S.; Plötz, Joachim; Steinhage, Daniel; Boveng, Peter

    2017-01-01

    The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga , Weddell seal Leptonychotes weddellii , Ross seal Ommatophoca rossii and leopard seal Hydrurga leptonyx and to identify ecological relationships and habitat use patterns. The Atlantic sector of the Southern Ocean (the eastern sector of the Weddell Sea) was surveyed by research teams from Germany, Norway and South Africa usi...

  3. A new species of Halcampella (Actiniaria, Halcampoididae from the eastern Weddell Sea and Antarctic Peninsula

    Directory of Open Access Journals (Sweden)

    Estefanía Rodríguez

    2002-03-01

    Full Text Available A new species of soft-bottom-dwelling sea anemone of the genus Halcampella is described and illustrated based on 47 specimens collected during the Polarstern cruises ANT XV/3 and ANT XVII/3 to the Antarctic Peninsula and the eastern Weddell Sea. The new Halcampella species is easily distinguishable from its congeners by the number of cycles of mesenteries and tentacles, the cnidae and the geographic distribution. The new species is described and compared to the available type material of the other species of the genus and new cnidae data are given for H. maxima Hertwig, 1888 and H. robusta Carlgren, 1931. According to other authors H. endromitata (Andres, 1881 is considered a nomen dubium and H. maxima is here proposed as the types species of the genus.

  4. On the forcing mechanisms of mesocyclones in the eastern Weddell Sea region, Antarctica: Process studies using a mesoscale numerical model

    Directory of Open Access Journals (Sweden)

    Thomas Klein

    2001-04-01

    Full Text Available Development mechanisms of Antarctic mesocyclones in the eastern Weddell Sea area are examined by means of simulations with a mesoscale model using different idealized initial conditions. In one of the experiments, a mesocyclone develops over an area of open water close to the coast of the Antarctic continent. The forcing mechanisms of this mesocyclogenesis are investigated by means of sensitivity studies in which certain physical processes and the relevance of the surface conditions topography, sea surface temperature and sea ice coverage are examined. The sensitivity experiments show that the simulated mesocyclone is forced by an interaction of several forcing mechanisms at different stages of the development rather than by a single mechanism. The topography of the eastern Weddell Sea region and the summertime coastal polynia are shown to be of great importance for the mesocyclogenesis. A suitable synoptic-scale flow is necessary to support the katabatic flow over the sloped ice sheet, and to enhance the generation of cyclonic vorticity due to vertical stretching for the initial mesocyclogenesis. The diabatic process of the convergence of the sensible and latent heat fluxes in the boundary layer over the coastal polynia then becomes the dominant forcing mechanism for the further development of the mesocyclone.

  5. Effects of hydrographic variability on the spatial, seasonal and diel diving patterns of southern elephant seals in the eastern Weddell Sea.

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    Martin Biuw

    Full Text Available Weddell Sea hydrography and circulation is driven by influx of Circumpolar Deep Water (CDW from the Antarctic Circumpolar Current (ACC at its eastern margin. Entrainment and upwelling of this high-nutrient, oxygen-depleted water mass within the Weddell Gyre also supports the mesopelagic ecosystem within the gyre and the rich benthic community along the Antarctic shelf. We used Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs to examine the importance of hydrographic variability, ice cover and season on the movements and diving behavior of southern elephant seals in the eastern Weddell Sea region during their overwinter feeding trips from Bouvetøya. We developed a model describing diving depth as a function of local time of day to account for diel variation in diving behavior. Seals feeding in pelagic ice-free waters during the summer months displayed clear diel variation, with daytime dives reaching 500-1500 m and night-time targeting of the subsurface temperature and salinity maxima characteristic of CDW around 150-300 meters. This pattern was especially clear in the Weddell Cold and Warm Regimes within the gyre, occurred in the ACC, but was absent at the Dronning Maud Land shelf region where seals fed benthically. Diel variation was almost absent in pelagic feeding areas covered by winter sea ice, where seals targeted deep layers around 500-700 meters. Thus, elephant seals appear to switch between feeding strategies when moving between oceanic regimes or in response to seasonal environmental conditions. While they are on the shelf, they exploit the locally-rich benthic ecosystem, while diel patterns in pelagic waters in summer are probably a response to strong vertical migration patterns within the copepod-based pelagic food web. Behavioral flexibility that permits such switching between different feeding strategies may have important consequences regarding the potential for southern elephant seals to adapt to

  6. Weddell Sea exploration from ice station

    Science.gov (United States)

    Ice Station Weddell Group of Principal Investigators; Chief Scientists; Gordon, Arnold L.

    On January 18, 1915, the Endurance and Sir Ernest Shackleton and his crew were stranded in the ice of the Weddell Sea and began one of the most famous drifts in polar exploration. Shackleton turned a failure into a triumph by leading all of his team to safety [Shackleton, 1919]. The drift track of the Endurance and the ice floe occupied by her stranded crew after the ship was lost on November 21, 1915, at 68°38.5‧S and 52°26.5‧W, carried the group along the western rim of the Weddell Gyre, representing a rare human presence in this region of perennial sea-ice cover.Seventy-seven years later, in 1992, the first intentional scientific Southern Ocean ice drift station, Ice Station Weddell-1 (ISW-1), was established in the western Weddell Sea by a joint effort of the United States and Russia. ISW-1 followed the track of the Endurance closely (Figure 1) and gathered an impressive array of data in this largely unexplored corner of the Southern Ocean, the western edge of the Weddell Gyre.

  7. Glacial geomorphology of the northwestern Weddell Sea, eastern Antarctic Peninsula continental shelf: Shifting ice flow patterns during deglaciation

    Science.gov (United States)

    Campo, Jennifer M.; Wellner, Julia S.; Domack, Eugene; Lavoie, Caroline; Yoo, Kyu-Cheul

    2017-03-01

    During the Last Glacial Maximum, grounded ice from the expanded Antarctic Peninsula Ice Sheet extended across the continental shelf. Grounded and flowing ice created a distinctive array of glacial geomorphic features on the sea floor, which were then exposed as the ice sheet retreated. The recent disintegration of the northern parts of the Larsen Ice Shelf (Larsen A and B) have permitted acquisition of marine geophysical data in previously inaccessible and unmapped areas. We present a reconstruction of the evolving ice-flow path and ice sheet geometry of the eastern Antarctic Peninsula, with particular focus paid to newly surveyed areas that shed light on the dynamics of a marine-terminating glacial geomorphic environment, where ice shelves play a major role in grounding line stability. Shifting flow directions were mapped in several areas, including across the Seal Nunataks, which divide Larsen A and B, and offshore of Larsen C, indicating flow reorientation that reflects the changing ice sheet geometry as retreat neared the modern coastline. The measured flow indicators in this area reveal comparatively high elongation ratios (> 20), indicating rapid ice flow. Evidence of possible previous ice-shelf collapses are noted near the shelf break, further illustrating the critical, protective effect that ice shelves impart to marine-terminating glacial environments. Modern ice retreat is governed in part by reorganization of flow patterns accompanying grounding line movement; such reorganizations happened in the past and can aid understanding of modern processes.

  8. Physical and structural characteristics of Weddell Sea pack ice

    National Research Council Canada - National Science Library

    Gow, A.J; Ackley, S.F; Buck, K.R; Golden, K.M

    1987-01-01

    Recent studies by CRREL researchers of the dynamics and thermodynamics of sea ice in the Antarctic have included investigations of the physical and structural properties of pack ice in the Weddell Sea...

  9. East Weddell Sea echinoids from the JR275 expedition

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    Thomas Saucède

    2015-05-01

    Full Text Available Information regarding the echinoids in this dataset is based on the Agassiz Trawl (AGT and epibenthic sledge (EBS samples collected during the British Antarctic Survey cruise JR275 on the RRS James Clark Ross in the austral summer 2012. A total of 56 (1 at the South Orkneys and 55 in the Eastern Weddell Sea Agassiz Trawl and 18 (2 at the South Orkneys and 16 in the Eastern Weddell Sea epibenthic sledge deployments were performed at depths ranging from ~280 to ~2060 m. This presents a unique collection for the Antarctic benthic biodiversity assessment of an important group of benthic invertebrates. In total 487 specimens belonging to six families, 15 genera, and 22 morphospecies were collected. The species richness per station varied between one and six. Total species richness represents 27% of the 82 echinoid species ever recorded in the Southern Ocean (David et al. 2005b, Pierrat et al. 2012, Saucède et al. 2014. The Cidaridae (sub-family Ctenocidarinae and Schizasteridae are the two most speciose families in the dataset. They comprise seven and nine species respectively. This is illustrative of the overall pattern of echinoid diversity in the Southern Ocean where 65% of Antarctic species belong to the families Schizasteridae and Cidaridae (Pierrat et al. 2012.

  10. Weddell Sea ice drift: Kinematics and wind forcing

    Science.gov (United States)

    Vihma, Timo; Launiainen, Jouko; Uotila, Juha

    1996-08-01

    Ice drift in the Weddell Sea was studied on the basis of positional and meteorological data from Argos buoys drifting in 1990-1992 and surface pressure analyses from the European Centre for Medium Range Weather Forecasts (ECMWF). The drift kinematics showed differences between the eastern and western parts of the Weddell Sea. Close to the Antarctic Peninsula, the ice drifted as an almost nonrotating uniform field at a low speed, having reduced small-scale motions with little meandering, compared to regions further to the east. Inertial motion was detected from the ice drift in areas east of 35°W and in the region of the Antarctic Circumpolar Current. On timescales of days, wind was the primary forcing factor for the drift. A linear model between the wind and ice drift explained 40-80% of the drift velocity variance. The degree of explanation was higher in the central Weddell Sea (around 40°W) and lower closer to the Antarctic Peninsula. The geostrophic wind was found to provide almost as good a basis for the general drift estimation as the surface wind observed by the buoys, although strong cyclones were not well detected by the ECMWF analyses. The data suggest a dependency upon atmospheric stability such that stable stratification reduces the wind forcing on the drift. For 60-80% of the time the direction of the drift deviated less than 45° from the geostrophic wind and for 45-70% of the time less than 45° from the ocean current. Ice transport through a transect crossing the Weddell Sea from the Antarctic Peninsula tip to Kapp Norwegia was estimated on the basis of the geostrophic winds, the drift's observed response to the wind, and literature-based information on ice concentration and thickness. The estimated annual mean net export in 1992-1994 varied from 8000 to 22,000 m3/s. Most of the net export took place in winter and spring, export prevailing west of 35°W and import east of it.

  11. AWI Moored ULS Data, Weddell Sea (1990-1998)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of moored Upward Looking Sonar (ULS) data from 14 stations in the Weddell Sea. Parameters in the processed data files are water pressure,...

  12. Quantification of sea ice production in Weddell Sea polynyas

    Science.gov (United States)

    Zentek, Rolf; Heinemann, Günther; Paul, Stephan; Stulic, Lukrecia; Timmermann, Ralph

    2017-04-01

    The regional climate model COSMO-CLM was used to perform simulations the Weddell Sea region in Antarctica for the time period 2002-2015 with the focus on atmosphere-ocean-sea ice interactions. The original model was adapted to polar regions by the use of a thermodynamic sea ice module with snow cover and an temperature-dependent albedo scheme for sea ice. The recently published topography RTopo2 was used. The model was run with nesting in ERA-Interim data in a forecast mode. Sea ice concentrations were taken from satellite measurements (AMSR-E, SSMI/S, AMSR2) and were updated daily to allow for a close-to-reality hindcast. Simulations were done with 15 km resolution for the whole period 2002-2015 with the goal to force the sea-ice ocean model FESOM. In a second step a 5 km simulation was one-way nested for the winter period (April - September) 2002-2015 to allow for a better quantification of sea ice production in the Weddell Sea. Estimates of sea ice production and comparisons of the results to remote sensing data will be presented.

  13. Albedo of the ice-covered Weddell and Bellingshausen Sea

    OpenAIRE

    Weiss, A.I.; King, J C; T. A. Lachlan-Cope; Ladkin, R. S.

    2011-01-01

    This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo which were conducted in the sea ice areas of the Weddell and Bellingshausen Sea show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albed...

  14. Role of Weddell Sea ice variability in southern African climate

    Science.gov (United States)

    Morioka, Y.; Engelbrecht, F.; Behera, S. K.

    2016-12-01

    A role of interannual sea ice variability in the Weddell Sea on southern African climate is investigated by conducting data analysis and coupled general circulation model (CGCM) experiments. The Weddell Sea ice exhibits a distinct interannual variability during austral summer when the southern African rainfall experiences most of its annual rainfall. The sea ice concentration (SIC) in the Weddell Sea shows a significantly negative correlation with the southern African rainfall during early summer (Nov-Jan). The low SIC anomaly in the Weddell Sea is associated with anticyclonic atmospheric circulation anomalies in the South Atlantic and southern Indian Oceans, which facilitates more moisture advection from the southern Indian Ocean. Composite analysis reveals that the low SIC anomaly in the Weddell Sea is attributed to the increased solar radiation and the northwesterly wind anomaly. This low SIC anomaly, in turn, acts to cause warmer skin temperature and reduce the meridional temperature gradient to the north. This is a favoring condition for sustaining the anticyclonic circulation anomaly in the South Atlantic by enhancing the near-surface atmospheric stability. This intriguing association between the SIC and atmospheric circulation anomalies is also simulated in a series of CGCM experiment, e.g. where the interannual sea surface temperature (SST) variability in the tropics and midlatitudes is suppressed by the monthly climatology of the model. However, in the absence of interannual SST variability over global oceans, the simulated SIC anomaly is much smaller in association with the atmospheric internal variability, called the Southern Annular Mode. These CGCM results suggest that the air-sea-ice interaction in the Weddell Sea has potential impact on the overlying atmosphere in the South Atlantic, which is important for the southern African climate.

  15. Albedo of the ice covered Weddell and Bellingshausen Seas

    Directory of Open Access Journals (Sweden)

    A. I. Weiss

    2012-04-01

    Full Text Available This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo, which were conducted in the sea ice areas of the Weddell and Bellingshausen Seas show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albedo of αi = 0.64 ± 0.2 (± standard deviation. The mean sea ice albedo of the pack ice area in the western Weddell Sea was αi = 0.75 ± 0.05. In the southern Weddell Sea, where new, young sea ice prevailed, a mean albedo value of αi = 0.38 ± 0.08 was observed. Relatively warm open water and thin, newly formed ice had the lowest albedo values, whereas relatively cold and snow covered pack ice had the highest albedo values. All sea ice areas consisted of a mixture of a large range of different sea ice types. An investigation of commonly used parameterizations of albedo as a function of surface temperature in the Weddell and Bellingshausen Sea ice areas showed that the albedo parameterizations do not work well for areas with new, young ice.

  16. Albedo of the ice covered Weddell and Bellingshausen Seas

    OpenAIRE

    Weiss, A.I.; King, J C; T. A. Lachlan-Cope; Ladkin, R. S.

    2012-01-01

    This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo, which were conducted in the sea ice areas of the Weddell and Bellingshausen Seas show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albedo o...

  17. Numerical simulation of the Weddell Sea pack ice

    Science.gov (United States)

    Hibler, W. D., III; Ackley, S. F.

    1983-01-01

    In order to determine the degree to which a coupled dynamic thermodynamic model can reproduce the seasonal cycle of the Antarctic Sea ice in the Weddell Sea, a series of two-year simulations of the Weddell Sea ice pack were carried out. The simulations employed Hibler's (1979) model and used a one-day time step on an 18 x 15 grid with a resolution of 222 km. Daily atmospheric data from 1979 were used to drive the simulations. The simulations yielded a seasonal cycle of ice with maximum and minimum extents close to that observed. Except for portions of the western Weddell, the advance of the ice is found to be primarily thermodynamic in nature, while the rapid decay depends critically on the presence of both leads and lateral ice advection. In early summer the ice motion causes a residual tongue of ice to extend eastward from the Antarctic Peninsula in agreement with observations. Mean ice thicknesses are consistent with observations, as are the mean drift rates of about 5 km/day.

  18. Dissolved Fe across the Weddell Sea and Drake Passage: impact of DFe on nutrient uptake

    NARCIS (Netherlands)

    Klunder, M.B.; Laan, P.; de Baar, H.J.W.; Middag, R.; Neven, I.; Van Ooijen, J.

    2014-01-01

    This manuscript reports the first full depth distributions of dissolved iron (DFe) over a high-resolution Weddell Sea and Drake Passage transect. Very low dissolved DFe concentrations (0.01-0.1 nM range) were observed in the surface waters of the Weddell Sea, and within the Drake Passage polar

  19. Dissolved Fe across the Weddell Sea and Drake Passage : Impact of DFe on nutrient uptake

    NARCIS (Netherlands)

    Klunder, M. B.; Laan, P.; De Baar, H. J. W.; Middag, R.; Neven, I.; Van Ooijen, J.

    2014-01-01

    This manuscript reports the first full depth distributions of dissolved iron (DFe) over a high-resolution Weddell Sea and Drake Passage transect. Very low dissolved DFe concentrations (0.01-0.1 nM range) were observed in the surface waters of the Weddell Sea, and within the Drake Passage polar

  20. On the freshening of the northwestern Weddell Sea continental shelf

    Directory of Open Access Journals (Sweden)

    H. H. Hellmer

    2011-05-01

    Full Text Available We analyzed hydrographic data from the northwestern Weddell Sea continental shelf of the three austral winters 1989, 1997, and 2006 and two summers following the last winter cruise. During summer a thermal front exists at ~64° S separating cold southern waters from warm northern waters that have similar characteristics as the deep waters of the central basin of the Bransfield Strait. In winter, the whole continental shelf exhibits southern characteristics with high Neon (Ne concentrations, indicating a significant input of glacial melt water. The comparison of the winter data from the shallow shelf off the tip of the Antarctic Peninsula, spanning a period of 17 yr, shows a salinity decrease of 0.09 for the whole water column, which has a residence time of <1 yr. We interpret this freshening as being caused by a combination of reduced salt input due to a southward sea ice retreat and higher precipitation during the late 20th century on the western Weddell Sea continental shelf. However, less salinification might also result from a delicate interplay between enhanced salt input due to sea ice formation in coastal areas formerly occupied by Larsen A and B ice shelves and increased Larsen C ice loss.

  1. Carbonate Chemistry of the Weddell Sea from 10/9/1981 - 11/25/1981 (NODC Accession 0000121)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Carbonate data for the Weddell sea are provided from both surface samples taken along the cruise track of the US-USSR Weddell Polynya Expedition (WEPOLEX-81) and...

  2. Turbulent mixing under drifting pack ice in the weddell sea.

    Science.gov (United States)

    McPhee, M G; Martinson, D G

    1994-01-14

    By providing cold, dense water that sinks and mixes to fill the abyssal world ocean, high-latitude air-sea-ice interaction is the main conduit through which the deep ocean communicates with the rest of the climate system. A key element in modeling and predicting oceanic impact on climate is understanding the processes that control the near surface exchange of heat, salt, and momentum. In 1992, the United States-Russian Ice Station Weddell-1 traversed the western Weddell Sea during the onset of winter, providing a platform for direct measurement of turbulent heat flux and Reynolds stress in the upper ocean. Data from a storm early in the drift indicated (i) well-formed Ekman spirals (in both velocity and turbulent stress); (ii) high correlation between mixed layer heat flux and temperature gradients; (iii) that eddy viscosity and eddy thermal diffusivity were similar, about 0.02 square meters per second; and (iv) that the significant turbulent length scale (2 to 3 meters through most of the boundary layer) was proportional to the wavelength at the peak in the weighted vertical velocity spectrum. The measurements were consistent with a simple model in which the bulk eddy viscosity in the neutrally buoyant mixed layer is proportional to kinematic boundary stress divided by the Coriolis parameter.

  3. Atmospheric Response to Weddell Sea Open-Ocean Polynya

    Energy Technology Data Exchange (ETDEWEB)

    Hodos, Travis [United States Air Force Academy, Colorado Springs, CO (United States); Weijer, Wilbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-02

    The atmospheric conditions associated with the rare Weddell Sea open ocean polynya are investigated. The polynya has not been seen since 1976, so data on the event is scarce. The CESM high resolution model is used to investigate multiple atmospheric variables. We analyze three years of polynyas, which are also compared to three years without a polynya. The surface temperature, sensible heat flux, latent heat flux, humidity, average wind speed, precipitation, longwave flux, and shortwave flux all increased over the polynya. The sensible heat flux had a higher magnitude than the latent heat flux because conduction and convection were the primary drivers of heat flux. A combination of increased latent heat flux and humidity led to an increase in precipitation. Increased longwave downwelling flux over the polynya indicated the presence of clouds over the polynya. Lastly, the sea level pressure was consistently lower over the polynya because of the presence of a thermal low generated by thermally driven convective updrafts.

  4. Quantification of sea ice production at coastal polynyas in the southern Weddell Sea

    Science.gov (United States)

    Stulic, Lukrecia; Timmermann, Ralph; Zentek, Rolf; Heinemann, Günther

    2017-04-01

    Sea ice production and associated High Salinity Shelf Water (HSSW) formation in the southern Weddell Sea is an important driver for the global thermohaline ocean circulation and determines the properties of shelf water inflow that fuels ice shelf basal melting. In the southern Weddell Sea, coastal polynyas cover 1% of the area, but contribute about 10% to the total winter sea ice production. This project aims to improve estimates of the sea ice production and HSSW formation in the southern Weddell Sea coastal polynyas by a synergy of numerical simulations and remote sensing data. Sea ice-ocean simulations are performed with the Finite Element Sea ice-Ocean Model (FESOM) with a horizontal resolution close to the Rossby radius over the whole Weddell Sea to better represent eddy dynamics. In order to asses sensitivity of polynya characteristics and HSSW formation rates to the atmospheric forcing, FESOM is forced with different reanalysis data (ERA-Interim, NCEP-CFSR). Mean sea ice growth for the simulated period (1979-2012) is lower and more localized along the coastline/ice shelf front in the NCEP-CFSR run. Differences may be attributed to the colder air temperatures and stronger offshore winds in ERA-Interim forcing. FESOM will be forced with output from the regional atmospheric model COSMO-CLM (CCLM) to further investigate sensitivity with respect to different atmospheric forcing. The best and most realistic ice production and HSSW formation estimates are expected to be obtained by assimilation of thin ice thickness data derived from MODIS retrievals into FESOM. This will lead to a high resolution data set of sea ice coverage and ice thickness fields that can be used as reference data set for other sea ice models and as an input for high-resolution atmospheric models.

  5. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 17

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  6. Benthic community productivity in the Magellan Region and in the Weddell Sea

    Directory of Open Access Journals (Sweden)

    Thomas Brey

    1999-12-01

    Full Text Available Our comparison of macrobenthic biomass, production and productivity of the Magellan region (14 - 349 m water depth and the Weddell Sea (132 - 548 m water depth is based on multi box corer samples collected in both areas. Biomass is slightly but not significantly lower in the Magellan region (7.3 g C m-2 than in the Weddell Sea (12.0 g C m-2. Annual production and P/B ratio are higher in the Magellan region (5.1 g C m-2 y-1, 0.7 y-1 as compared to the Weddell Sea (3.6 g C m-2 y-1, 0.3 y-1. In the Magellan region, Mollusca, Polychaeta and Arthropoda dominate benthic production, whereas in the Weddell Sea Polychaeta, Porifera and Echinodermata are the most productive taxa.

  7. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 19

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  8. Multichannel Seismic Reflection Data - SCAR - Weddell Sea - 1978, SDLS CD-ROM vol 18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are stacked multichannel marine seismic reflection data recorded during 1978 in the Weddell Sea and Queen Maud Land, Antarctica, by the Bundesanstalt fur...

  9. Morphology of sea ice pressure ridges in the northwestern Weddell Sea in winter

    Science.gov (United States)

    Tan, Bing; Li, Zhi-Jun; Lu, Peng; Haas, Christian; Nicolaus, Marcel

    2012-06-01

    To investigate the morphology and distribution of pressure ridges in the northwestern Weddell Sea, ice surface elevation profiles were measured by a helicopter-borne laser altimeter during Winter Weddell Outflow Study with the German R/V Polarstern in 2006. An optimal cutoff height of 0.62 m, derived from the best fits between the measured and theoretical ridge height and spacing distributions, was first used to separate pressure ridges from other sea ice surface undulations. It was found that the measured ridge height distribution was well modeled by a negative exponential function, and the ridge spacing distribution by a lognormal function. Next, based on the ridging intensity Ri (the ratio of mean ridge sail height to mean spacing), all profiles were clustered into three regimes by an improved k-means clustering algorithm: Ri ≤ 0.01, 0.01 0.026 (denoted as C1, C2, and C3 respectively). Mean (and standard deviation) of sail height was 0.99 (±0.07) m in Regime C1, 1.12 (±0.06) m in C2, and 1.17 (±0.04) m in C3, respectively, while the mean spacings (and standard deviations) were 232 (±240) m, 54 (±20) m, and 31 (±5.6) m. These three ice regimes coincided closely with distinct sea ice regions identified in a satellite radar image, where C1 corresponded to the broken ice in the marginal ice zone and level ice formed in the Larsen Polynya, C2 corresponded to the deformed first- and second-year ice formed by dynamic action in the center of the study region, and C3 corresponded to heavily deformed ice in the outflowing branch of the Weddell Gyre. The results of our analysis showed that the relationship between the mean ridge height and frequency was well modeled by a logarithmic function with a correlation coefficient of 0.8, although such correlation was weaker when considering each regime individually. The measured ridge height and frequency were both greater than those reported by others for the Ross Sea. Compared with reported values for other parts of the

  10. Repeated CFC sections at the Greenwich Meridian in the Weddell Sea

    Science.gov (United States)

    Klatt, Olaf; Roether, Wolfgang; Hoppema, Mario; Bulsiewicz, Klaus; Fleischmann, Uli; Rodehacke, Christian; Fahrbach, Eberhard; Weiss, Ray F.; Bullister, John L.

    2002-04-01

    Repeated observations of the tracer chlorofluorocarbon-11 (CFC-11) for a section along the Greenwich Meridian from Antarctica (70°S) to about 50°S are presented for the period 1984-1998. The CFC sections display a highly persistent pattern. A middepth CFC minimum in the central Weddell Sea is bounded laterally by elevated levels of dissolved CFCs at the southern margin of the Weddell Basin and by a column of elevated CFC concentrations around 55°S near to the northern margin. Part of the latter column covers waters of the Antarctic Circumpolar Current, which indicates that a moderate portion of these waters was ventilated in the Weddell Sea. Deep CFC maxima adjoining the southern and northern margins of the Weddell Basin indicate advective cores of recently ventilated waters. The southern core supports previous notions of deep water import into the Weddell Sea from the east. For all deep and bottom waters, the portions ventilated on the CFC timescale (~50 years) are small. Effective initial CFC saturations for these portions are estimated to be between 60 and 70%, using in part new data from off the Filchner-Ronne Ice Shelf. For various CFC features along the section (mostly advective cores), ventilated fractions and mean ages of these fractions were obtained (with error limits). The procedure was to fit an age distribution of a prescribed form to CFC-11 time series for these features, constructed from the various realizations of the CFC section. The ages are between 3 and 19 years, and the ventilated fractions range between 6 and 23%, indicating a rather limited ventilation of the interior Weddell Sea subsurface layer waters on the CFC timescale. It is shown that the concurrent CFC-12 data provide little additional information. The work demonstrates a high information content of repeated tracer observations and encourages similar approaches also in other ocean regions.

  11. Distribution patterns of macrozoobenthos: a comparison between the Magellan Region and the Weddell Sea (Antarctic

    Directory of Open Access Journals (Sweden)

    D. Gerdes

    1999-12-01

    Full Text Available The Joint Chilean-German-Italian Magellan Victor Hensen Campaign in October/November 1994 and the Polarstern expedition ANT XIII/4 (May 1996 yielded 207 quantitative multibox corer samples from 11 stations in the Paso Ancho (Magellan Straits, 10 stations in the Beagle Channel, and 15 stations of the shelf and continental slope off the eastern entrance of the Beagle Channel. Mean abundance values in the Magellan Region varied from 1591 Ind. M-2 in the Paso Ancho to 3643 Ind. m-2 in the Beagle Channel and 3983 Ind. m-2 on the shelf; the corresponding biomass values were 96.8 g, 301.6 g, and 119.0 g wet weight m-2 respectively. In terms of org. C the corresponding values are 4.8, 11.4, and 4.6 g m-2. Abundance (3806 Ind. m-2 and biomass (222.6 g wet weight m-2 or 7.3 g C data from the eastern Weddell Sea shelf (Polarstern expeditions ANT VI/3, 1987/88 and ANT VII/4, 1989 are in the same range. The composition of the fauna, however, reveals distinct differences.

  12. Distributions, trends and inter-annual variability of nutrients along a repeat section through the Weddell Sea (1996-2011)

    NARCIS (Netherlands)

    Hoppema, Mario; Bakker, Karel; van Heuven, Steven M. A. C.; van Ooijen, Jan C.; de Baar, Henricus

    2015-01-01

    Nutrient data from five repeat sections spanning 1996 to 2011 crossing the Weddell Sea are presented. These measurements have been standardized against the same reference material, yielding an outstanding internal consistency. The generic structure of the Weddell Gyre and its hydrographic features

  13. On the near-bottom variability in the northwestern Weddell Sea

    Science.gov (United States)

    Schröder, M.; Hellmer, H. H.; Absy, J. M.

    The thermohaline data from the first Brazilian hydrographic cruise to the northwestern Weddell Sea (AR XVIII) revealed significant near-bottom changes in water-column properties over seasonal and interannual time scales. Favorable ice conditions in 2000 allowed a dense station coverage of the area including the main pathways for Weddell Sea deep and bottom waters. The new results are compared with the data from the 1998 German cruise ANT XV/4 and other historical data. A warming of the bottom layer was discovered that was more attributable to short-term seasonal or interannual fluctuations in the formation of cold bottom water than to a long-term trend. There was both consistency and variation between and within seasons. Invariant bottom-water characteristics were observed in different seasons (summer/winter), and variable bottom-water characteristics were observed in the same season (summer) at the same locations. This reduces the possibility of a dominant seasonal effect. Instead, we propose that the intermittent behavior of small cold-water sources along the Weddell Sea's periphery causes the variability measured in the deep northwestern Weddell Sea. The observed variability has consequences for the water-mass export across the South Scotia Ridge, as the absence of the fresher/lighter Weddell Sea Bottom Water south of South Orkney Plateau during AR XVIII might be linked to a reduced ventilation of the deep Scotia Sea. The results of this study show the need for ongoing efforts for establishing a long-term monitoring of this region with global importance.

  14. A dynamically consistent analysis of circulation and transports in the southwestern Weddell Sea

    Directory of Open Access Journals (Sweden)

    M. Yaremchuk

    1998-08-01

    Full Text Available An inverse model is applied for the analysis of hydrographic and current meter data collected on the repeat WOCE section SR4 in the Weddell Sea in 1989–1992. The section crosses the Weddell Sea cyclonic gyre from Kapp Norvegia to the northern end of the Antarctic Peninsula. The concepts of geostrophy, conservation of planetary vorticity and hydrostatics are combined with advective balances of active and passive properties to provide a dynamically consistent circulation pattern. Our variational assimilation scheme allows the calculation of three-dimensional velocities in the section plane. Current speeds are small except along the coasts where they reach up to 12 cm/s. We diagnose a gyre transport of 34 Sverdrup which is associated with a poleward heat transport of 28×1012 W corresponding to an average heat flux of 15 Wm–2 in the Weddell Sea south of the transect. This exceeds the estimated local flux on the transect of 2 Wm–2. As the transect is located mostly in the open ocean, we conclude that the shelf areas contribute significantly to the ocean-atmosphere exchange and are consequently key areas for the contribution of the Weddell Sea to global ocean ventilation. Conversion of water masses occuring south of the section transform 6.6±1.1 Sv of the inflowing warm deep water into approximately equal amounts of Weddell Sea deep water and Weddell Sea bottom water. The volume transport of surface water equals in the in- and outflow. This means that almost all newly formed surface water is involved in the deep and bottom water formation. Comparison with the results obtained by pure velocity interpolation combined with a hydrographic data subset indicates major differences in the derived salt transports and the water mass conversion of the surface water. The differences can be explained by deviations in the structure of the upper ocean currents to which shelf areas contribute significantly. Additionally a rigorous variance analysis is

  15. Characteristics and distribution patterns of snow and meteoric ice in the Weddell Sea and their contribution to the mass balance of sea ice

    Directory of Open Access Journals (Sweden)

    Hajo Eicken

    Full Text Available Based on snow- and ice-thickness measurements at >11 000 points augmented by snow- and icecore studies during 4 expeditions from 1986 - 92 in the Weddell Sea, we describe characteristics and distribution patterns of snow and meteoric ice and assess their importance for the mass balance of sea ice. For first-year ice (FY in the central and eastern Weddell Sea, mean snow depth amounts to 0.16 m (mean ice thickness 0.75 m compared to 0.53 m (mean ice thickness 1.70 m for second-year ice (SY in the northwestern Weddell Sea. Ridged ice retains a thicker snow cover than level ice, with ice thickness and snow depth negatively correlated for the latter, most likely due to aeolian redistribution. During the different expeditions, 8, 15, 17 and 40% of all drill holes exhibited negative freeboard. As a result of flooding and brine seepage into the snow pack, snow salinities averaged 4‰. Through 18O measurements the distribution of meteoric ice (i.e. precipitation in the sea-ice cover was assessed. Roughly 4% of the total ice thickness consist of meteoric ice (FY 3%, SY 5%. With a mean density of 290 kg/m3, the snow cover itself contributes 8% to total ice mass (7% FY, 11% SY. Analysis of 18O in snow indicates a local maximum in accumulation in the 65 to 75°S latitude zone. Hydrogen peroxide in the snow has proven useful as a temporal tracer and for identification of second-year floes. Drawing on accumulation data from stations at the Weddell Sea coast, it becomes clear that the onset of ice growth is important for the evolution of ice thickness and the interaction between ice and snow. Loss of snow to leads due to wind drift may be considerable, yet is reduced owing to metamorphic processes in the snow column. This is confirmed by a comparison of accumulation data from coastal stations and from snow depths over sea ice. Temporal and spatial accumulation patterns of snow are shown to be important in controlling

  16. Characteristics and distribution patterns of snow and meteoric ice in the Weddell Sea and their contribution to the mass balance of sea ice

    Directory of Open Access Journals (Sweden)

    H. Eicken

    1994-01-01

    Full Text Available Based on snow- and ice-thickness measurements at >11 000 points augmented by snow- and icecore studies during 4 expeditions from 1986 - 92 in the Weddell Sea, we describe characteristics and distribution patterns of snow and meteoric ice and assess their importance for the mass balance of sea ice. For first-year ice (FY in the central and eastern Weddell Sea, mean snow depth amounts to 0.16 m (mean ice thickness 0.75 m compared to 0.53 m (mean ice thickness 1.70 m for second-year ice (SY in the northwestern Weddell Sea. Ridged ice retains a thicker snow cover than level ice, with ice thickness and snow depth negatively correlated for the latter, most likely due to aeolian redistribution. During the different expeditions, 8, 15, 17 and 40% of all drill holes exhibited negative freeboard. As a result of flooding and brine seepage into the snow pack, snow salinities averaged 4‰. Through 18O measurements the distribution of meteoric ice (i.e. precipitation in the sea-ice cover was assessed. Roughly 4% of the total ice thickness consist of meteoric ice (FY 3%, SY 5%. With a mean density of 290 kg/m3, the snow cover itself contributes 8% to total ice mass (7% FY, 11% SY. Analysis of ∆18O in snow indicates a local maximum in accumulation in the 65 to 75°S latitude zone. Hydrogen peroxide in the snow has proven useful as a temporal tracer and for identification of second-year floes. Drawing on accumulation data from stations at the Weddell Sea coast, it becomes clear that the onset of ice growth is important for the evolution of ice thickness and the interaction between ice and snow. Loss of snow to leads due to wind drift may be considerable, yet is reduced owing to metamorphic processes in the snow column. This is confirmed by a comparison of accumulation data from coastal stations and from snow depths over sea ice. Temporal and spatial accumulation patterns of snow are shown to be important in controlling the sea-ice cover evolution.

  17. Three new species of deep-sea Gromia (Protista, Rhizaria) from the bathyal and abyssal Weddell Sea, Antarctica

    DEFF Research Database (Denmark)

    Rothe, Nina; Gooday, Andrew J.; Cedhagen, Tomas

    2009-01-01

    We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the ...

  18. New records of Antarctic and Sub-Antarctic sea anemones (Cnidaria, Anthozoa, Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and Scotia Arc.

    Science.gov (United States)

    Rodríguez, Estefanía

    2013-01-01

    Herein we provide new records for 22 Antarctic species of sea anemone sensu lato (Anthozoa: Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and the Scotia Sea. We provided short descriptions, images of the external morphology of preserved specimens (but also of living specimens in most cases), cnida data, and distribution maps for each studied species. New records are presented for nine species in the Weddell Sea and the geographic or bathymetric distributions for 19 of the 22 studied species are extended.

  19. Asteroids, ophiuroids and holothurians from the southeastern Weddell Sea (Southern Ocean

    Directory of Open Access Journals (Sweden)

    Julian Gutt

    2014-08-01

    Full Text Available Until the early 1980s, the composition and distribution of the asteroid (starfish, ophiuroid (brittle star and holothurian (sea cucumber bottom fauna of the southeastern Weddell Sea was virtually unknown. This southernmost part of the Atlantic sector of the Southern Ocean is a typical high-latitude Antarctic region located in the circumpolar permanent pack-ice zone. It became accessible for large-scale scientific surveys only through the availability of modern ice-breaking research vessels, such as the German RV “Polarstern”. Here, we describe a dataset of the faunal composition and abundance of starfish, brittle star and sea cucumber assemblages in this area, based on collections from trawl catches carried out during three “Polarstern” cruises in 1983, 1984 and 1985. The set comprises a total of 4,509 records of abundances of 35 asteroid species (with a total of 2,089 specimens and 38 ophiuroid species (with a total of 18,484 specimens from 34 stations, as well as of 66 holothurian species (with a total of 20,918 specimens from 59 stations including zero-abundances (absences. A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. Overall, starfishes, brittle stars and sea cucumbers were present at all sites investigated in the study area but composition and abundance of asterozoan (asteroids and ophiuroids together and holothurian fauna varied considerably. A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. In the case of asterozoans, water depth and latitude seemed to be the most important drivers of assemblage distribution and composition. One of the holothurian assemblages was part of the rich macrozoobenthic community dominated by a diverse and

  20. Asteroids, ophiuroids and holothurians from the southeastern Weddell Sea (Southern Ocean).

    Science.gov (United States)

    Gutt, Julian; Piepenburg, Dieter; Voß, Joachim

    2014-01-01

    Until the early 1980s, the composition and distribution of the asteroid (starfish), ophiuroid (brittle star) and holothurian (sea cucumber) bottom fauna of the southeastern Weddell Sea was virtually unknown. This southernmost part of the Atlantic sector of the Southern Ocean is a typical high-latitude Antarctic region located in the circumpolar permanent pack-ice zone. It became accessible for large-scale scientific surveys only through the availability of modern ice-breaking research vessels, such as the German RV "Polarstern". Here, we describe a dataset of the faunal composition and abundance of starfish, brittle star and sea cucumber assemblages in this area, based on collections from trawl catches carried out during three "Polarstern" cruises in 1983, 1984 and 1985. The set comprises a total of 4,509 records of abundances of 35 asteroid species (with a total of 2,089 specimens) and 38 ophiuroid species (with a total of 18,484 specimens) from 34 stations, as well as of 66 holothurian species (with a total of 20,918 specimens) from 59 stations including zero-abundances (absences). A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. Overall, starfishes, brittle stars and sea cucumbers were present at all sites investigated in the study area but composition and abundance of asterozoan (asteroids and ophiuroids together) and holothurian fauna varied considerably. A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. In the case of asterozoans, water depth and latitude seemed to be the most important drivers of assemblage distribution and composition. One of the holothurian assemblages was part of the rich macrozoobenthic community dominated by a diverse and abundant epifauna, mainly

  1. Southern Ocean ventilation and bottom water formation driven by Weddell Sea polynyas

    Science.gov (United States)

    Rheinlaender, Jonathan; Nisancioglu, Kerim; Smedsrud, Lars Henrik

    2017-04-01

    A distinct feature of the last glacial period, are the abrupt temperature fluctuations in Greenland associated with Dansgaard-Oeschger events and a similar but opposite response in Antarctica. The prevailing hypothesis behind this inter-hemispheric coupling, points to changes in deep water formation as the main driver, thus highlighting the pivotal role of the high latitude oceans in global climate. Bottom water formation through open-ocean deep convection in an Antarctic polynya, a large open water area inside the winter sea ice cover, provide a potential mechanism to trigger such changes in ocean circulation. In this study, an ocean-sea ice only version of the Norwegian Earth System Model (NorESM) is explored and shows strong open-ocean deep convection associated with large polynyas in the Weddell Sea. This provides us with an opportunity to test (1) how internal ocean dynamics can trigger abrupt changes in sea-ice cover and (2) how these polynyas affect the overturning circulation through changes in bottom water formation. During the 1,000 year long free-running simulation two polynyas are observed. We show, that the polynya is caused by subsurface warming leading to a gradual weakening of the surface stratification which destabilizes the whole water column and eventually triggers deep convective overturning. This mixes up relatively warm deep water causing extensive melt of sea ice in the Weddell Sea, while cold and fresh surface water sinks to the bottom. Consequently, the polynya leads to extensive bottom water formation and increase in the northward flow of Antarctic Bottom Water, while the southward flow of North Atlantic Deep Water is reduced. Finally, our results suggest that a decrease in the temperature of warm deep water in the Weddell Sea leads to cessation of open-ocean deep convection. This raises the question if open-ocean deep convection associated with polynyas in the Southern Ocean could be a realistic feature in a cold, glacial climate.

  2. Density of pack-ice seals and penguins in the western Weddell Sea in relation to ice thickness and ocean depth

    NARCIS (Netherlands)

    Florentino De Souza Silva, A.P.; Haas, C.; Franeker, van J.A.; Meesters, H.W.G.

    2008-01-01

    Aerial band transect censuses were carried out parallel with ice thickness profiling surveys in the pack ice of the western Weddell Sea during the ISPOL (Ice Station POLarstern) expedition of R.V. Polarstern from November 2004 to January 2005. Three regions were surveyed: the deep sea of the Weddell

  3. Scientific background document in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica) - Version 2015 - Part A: General context of the establishment of MPAs and background information on the Weddell Sea MPA planning area-

    OpenAIRE

    Teschke, Katharina; Beaver, Daniel; Bester, Marthán; Bombosch, Annette; Bornemann, Horst; Brandt, Angelika; Brtnik, Patricia; De Broyer, Claude; Burkhardt, Elke; Dieckmann, Gerhard; Douglass, Lucinda; Flores, Hauke; Gerdes, Dieter; Griffiths, Huw; Gutt, Julian

    2015-01-01

    Germany intends to present the Working Group on Ecosystem Monitoring and Management (WG EMM) the background document that provides the scientific basis for the evaluation of a marine protected area (MPA) in the Weddell Sea planning area. The contents and structure of the whole document reflect its main objectives, i.e. to set out the general context of the establishment of MPAs and to provide the background information on the Weddell Sea MPA (WSMPA) planning area (Part A); to inform on the da...

  4. A dynamically consistent analysis of circulation and transports in the southwestern Weddell Sea

    Directory of Open Access Journals (Sweden)

    M. Yaremchuk

    Full Text Available An inverse model is applied for the analysis of hydrographic and current meter data collected on the repeat WOCE section SR4 in the Weddell Sea in 1989–1992. The section crosses the Weddell Sea cyclonic gyre from Kapp Norvegia to the northern end of the Antarctic Peninsula. The concepts of geostrophy, conservation of planetary vorticity and hydrostatics are combined with advective balances of active and passive properties to provide a dynamically consistent circulation pattern. Our variational assimilation scheme allows the calculation of three-dimensional velocities in the section plane. Current speeds are small except along the coasts where they reach up to 12 cm/s. We diagnose a gyre transport of 34 Sverdrup which is associated with a poleward heat transport of 28×1012 W corresponding to an average heat flux of 15 Wm–2 in the Weddell Sea south of the transect. This exceeds the estimated local flux on the transect of 2 Wm–2. As the transect is located mostly in the open ocean, we conclude that the shelf areas contribute significantly to the ocean-atmosphere exchange and are consequently key areas for the contribution of the Weddell Sea to global ocean ventilation. Conversion of water masses occuring south of the section transform 6.6±1.1 Sv of the inflowing warm deep water into approximately equal amounts of Weddell Sea deep water and Weddell Sea bottom water. The volume transport of surface water equals in the in- and outflow. This means that almost all newly formed surface water is involved in the deep and bottom water formation. Comparison with the results obtained by pure velocity interpolation combined with a hydrographic data subset indicates major differences in the derived salt transports and the water mass conversion of the surface water. The differences can be explained by deviations in the structure of the upper ocean currents to which shelf areas contribute significantly. Additionally a

  5. Geology, geophysics, and hydrocarbon potential of Antarctica continental margin of Weddell Sea

    Energy Technology Data Exchange (ETDEWEB)

    Hinz, K.; Kristoffersen, Y.

    1987-05-01

    A prominent escarpment, called the Explora-Andenes Escarpment, has been recognized between long. 40/sup 0/W, lat. 72/sup 0/40'S and long. 10/sup 0/W, lat. 69/sup 0/20'S. It separates the continental margin from the Weddell Sea basin. Their recent MCS data have revealed the presence of some remarkably symmetric structures beneath a thick pile of tectonically undisturbed sediments. For example, two extensive wedge-shaped basement units occur between 20/sup 0/W and 40/sup 0/W. These units are characterized by a pattern of divergent reflectors which surround an elongated depression in basement. The northern wedge terminates against the Explora-Andenes Escarpment between 25/sup 0/W and 30/sup 0/W. The southern wedge, known as the Explora Wedge, shows a northward-dipping reflection pattern. The seismic characteristics suggest that both wedges consist of volcanic rocks. The basement depression is interpreted as a failed rift basin. The initial fragmentation of Gondwana was accompanied by prolific volcanism, which led to the emplacement of the wedges of dipping reflectors. The tectonomagmatic/volcanic period was followed by transtensional movements between Africa and Antarctica. This phase was heralded by the formation of the Explora-Andenes Escarpment as a new plate boundary and the opening of the Weddell Sea by sea-floor spreading. The Explora-Andenes Escarpment cuts across the early rift structures.

  6. Organic iodine in Antarctic sea ice: A comparison between winter in the Weddell Sea and summer in the Amundsen Sea

    Science.gov (United States)

    Granfors, Anna; Ahnoff, Martin; Mills, Matthew M.; Abrahamsson, Katarina

    2014-12-01

    Recent studies have recognized sea ice as a source of reactive iodine to the Antarctic boundary layer. Volatile iodinated compounds (iodocarbons) are released from sea ice, and they have been suggested to contribute to the formation of iodine oxide (IO), which takes part in tropospheric ozone destruction in the polar spring. We measured iodocarbons (CH3I, CH2ClI, CH2BrI, and CH2I2) in sea ice, snow, brine, and air during two expeditions to Antarctica, OSO 10/11 to the Amundsen Sea during austral summer and ANT XXIX/6 to the Weddell Sea in austral winter. These are the first reported measurements of iodocarbons from the Antarctic winter. Iodocarbons were enriched in sea ice in relation to seawater in both summer and winter. During summer, the positive relationship to chlorophyll a biomass indicated a biological origin. We suggest that CH3I is formed biotically in sea ice during both summer and winter. For CH2ClI, CH2BrI, and CH2I2, an additional abiotic source at the snow/ice interface in winter is suggested. Elevated air concentrations of CH3I and CH2ClI during winter indicate that they are enriched in lower troposphere and may take part in the formation of IO at polar sunrise.

  7. Macro- and megabenthic assemblages in the bathyal and abyssal Weddell Sea (Southern Ocean)

    Science.gov (United States)

    Linse, Katrin; Brandt, Angelika; Bohn, Jens M.; Danis, Bruno; De Broyer, Claude; Ebbe, Brigitte; Heterier, Vincent; Janussen, Dorte; López González, Pablo J.; Schüller, Myriam; Schwabe, Enrico; Thomson, Michael R. A.

    2007-08-01

    The assemblages inhabiting the continental shelf around Antarctica are known to be very patchy, in large part due to deep iceberg impacts. The present study shows that richness and abundance of much deeper benthos, at slope and abyssal depths, also vary greatly in the Southern and South Atlantic oceans. On the ANDEEP III expedition, we deployed 16 Agassiz trawls to sample the zoobenthos at depths from 1055 to 4930 m across the northern Weddell Sea and two South Atlantic basins. A total of 5933 specimens, belonging to 44 higher taxonomic groups, were collected. Overall the most frequent taxa were Ophiuroidea, Bivalvia, Polychaeta and Asteroidea, and the most abundant taxa were Malacostraca, Polychaeta and Bivalvia. Species richness per station varied from 6 to 148. The taxonomic composition of assemblages, based on relative taxon richness, varied considerably between sites but showed no relation to depth. The former three most abundant taxa accounted for 10-30% each of all taxa present. Standardised abundances based on trawl catches varied between 1 and 252 individuals per 1000 m 2. Abundance significantly decreased with increasing depth, and assemblages showed high patchiness in their distribution. Cluster analysis based on relative abundance showed changes of community structure that were not linked to depth, area, sediment grain size or temperature. Generally abundances of zoobenthos in the abyssal Weddell Sea are lower than shelf abundances by several orders of magnitude.

  8. New data on Weddell seal (Leptonychotes weddellii) colonies: A genetic analysis of a top predator from the Ross Sea, Antarctica.

    Science.gov (United States)

    Zappes, Ighor Antunes; Fabiani, Anna; Sbordoni, Valerio; Rakaj, Arnold; Palozzi, Roberto; Allegrucci, Giuliana

    2017-01-01

    In this paper, we studied the genetic variability in Weddell seal from colonies in Terra Nova Bay and Wood Bay, both sites located in the Ross Sea area, Antarctica. Two mitochondrial genes and one nuclear gene, with different mutation rates, were sequenced to investigate the haplotype diversity of the colonies and to test for a possible recent expansion. Fifteen microsatellites were used to analyze their genetic structure. Sequenced genes and microsatellites were also used to estimate the effective population size of the studied colonies and the Ross Sea seal population. The Ross Sea has a high density population of Weddel seals, with an estimated effective number of 50,000 females, and 1,341 individuals for the sampling area, possibly due to its high primary production. The colonies showed high diversity (Hd > 0.90) and many exclusive haplotypes (> 75%), likely a consequence of the surprisingly high site fidelity of Weddell seals, despite the proximity of the colonies. Nevertheless, there was low microsatellite differentiation between colonies, suggesting that they are part of a single larger population. Their expansion seemed to have started during the last glacial cycle (around 58,000 years ago), indicating that the Ross Sea seal populations have been present in the area for long time, probably due to the lack of hunting by humans and terrestrial predation. As a top predator, the role of Weddell seals in the Ross Sea ecology is crucial, and its demographic dynamics should be monitored to follow the future changes of such an important ecosystem.

  9. Basic epidemiological data on metazoan parasites of notothenioid fish off James Ross Island (Prince Gustav Channel, Weddell Sea), Antarctica

    Czech Academy of Sciences Publication Activity Database

    Nezhybová, Veronika; Mašová, Š.

    2015-01-01

    Roč. 5, č. 1 (2015), s. 44-54 ISSN 1805-0689 R&D Projects: GA ČR(CZ) GBP505/12/G112 Institutional support: RVO:68081766 Keywords : Host * Notothenioid fish * Parasites * Prince Gustav Channel * Weddell Sea Subject RIV: EG - Zoology

  10. Stratification and the distribution of phytoplankton, nutrients, inorganic carbon, and sulfur in the surface waters of Weddell Sea leads

    NARCIS (Netherlands)

    Zemmelink, H. J.; Houghton, L.; Dacey, J. W. H.; Stefels, J.; Koch, B. P.; Wisotzki, A.; Scheltz, A.; Thomas, D. N.; Papadimitriou, S.; Kennedy, H.; Kuosa, H.; Dittmar, T.

    2008-01-01

    The distribution (fine resolution depth profiles) of major nutrients, chlorophyll-a, organic compounds, and phytoplankton (biomass and numbers) was examined in lead water in pack ice of the Weddell Sea. Samples were taken by pulling water into a syringe from a series of depths from 0.002 to 4m.

  11. Macrostylis cerritus sp nov., a new species of Macrostylidae (Isopoda : Asellota) from the Weddell Sea, Southern Ocean

    NARCIS (Netherlands)

    Vey, Aidan; Brix, Saskia

    2009-01-01

    Macrostylis cerritus sp. nov. (Macrostylidae) is described from the Weddell Sea, Antarctica, at a depth of 2149 m. The new species differs from other species of Macrostylis due to the incisor with 4 cusps; the strongly hook-shaped ischium of pereopod 3; pereopod 4 being greatly reduced and juvenile

  12. Seabed images from Southern Ocean shelf regions off the northern Antarctic Peninsula and in the southeastern Weddell Sea

    Science.gov (United States)

    Piepenburg, Dieter; Buschmann, Alexander; Driemel, Amelie; Grobe, Hannes; Gutt, Julian; Schumacher, Stefanie; Segelken-Voigt, Alexandra; Sieger, Rainer

    2017-07-01

    Recent advances in underwater imaging technology allow for the gathering of invaluable scientific information on seafloor ecosystems, such as direct in situ views of seabed habitats and quantitative data on the composition, diversity, abundance, and distribution of epibenthic fauna. The imaging approach has been extensively used within the research project DynAMo (Dynamics of Antarctic Marine Shelf Ecosystems) at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI), which aimed to comparatively assess the pace and quality of the dynamics of Southern Ocean benthos. Within this framework, epibenthic spatial distribution patterns have been comparatively investigated in two regions in the Atlantic sector of the Southern Ocean: the shelf areas off the northern tip of the Antarctic Peninsula, representing a region with above-average warming of surface waters and sea-ice reduction, and the shelves of the eastern Weddell Sea as an example of a stable high-Antarctic marine environment that is not (yet) affected by climate change. The AWI Ocean Floor Observation System (OFOS) was used to collect seabed imagery during two cruises of the German research vessel Polarstern, ANT-XXIX/3 (PS81) to the Antarctic Peninsula from January to March 2013 and ANT-XXXI/2 (PS96) to the Weddell Sea from December 2015 to February 2016. Here, we report on the image and data collections gathered during these cruises. During PS81, OFOS was successfully deployed at a total of 31 stations at water depths between 29 and 784 m. At most stations, series of 500 to 530 pictures ( > 15 000 in total, each depicting a seabed area of approximately 3.45 m2 or 2.3 × 1.5 m) were taken along transects approximately 3.7 km in length. During PS96, OFOS was used at a total of 13 stations at water depths between 200 and 754 m, yielding series of 110 to 293 photos (2670 in total) along transects 0.9 to 2.6 km in length. All seabed images taken during the two cruises

  13. Protists from the ice-edge region of the Weddell Sea

    Science.gov (United States)

    Buck, Kurt R.; Garrison, David L.

    1983-12-01

    We present some of the first records and quantitative data on protists from the ice-edge region of the Weddell Sea. Major groups were diatoms (33 species), dinoflagellates (4 species), prymnesiophytes (2 species), cryptomonads (2 species), prasinophytes (1 species), chrysophytes (3 species), and choanoflagellates (11 species). The prymnesiophyte, Phaeocystis pouchetii, diatoms (predominantly Nitzschia of the Fragilariopsis group), and choanogflagellates (Acanthoecidae) were numerically dominant, although other protists sometimes contributed significantly to plankton populations. Most groups were more abundant at the ice edge than under the pack ice or in the open water. The abundance of choanoflagellates suggests that food chains based on bacterial production must be important, as well as the traditional diatom-krill-vertebrate food chain.

  14. Early Pliocene Weddell Sea climate and seasonality reconstructed from bivalves and bryozoans

    Science.gov (United States)

    Williams, M.; Clark, N.; Okamura, B.; Zalasiewicz, J.; Johnson, A.; Leng, M. J.; Smellie, J.; Haywood, A.; Nelson-Laloe, A.; Taylor, P.

    2010-12-01

    Early Pliocene marine cheilostome bryozoans and bivalves are preserved in glacigenic and interglacial marine deposits of James Ross Island and Cockburn Island, northern Antarctic Peninsula. Several different marine bryozoan genera were incorporated into diamictites during Pliocene ice advance(s). Bryozoan zooid-size Mean Annual Range of Temperature (zs-MART) analysis provides estimates of seasonality which suggest annual marine temperatures for the James Ross Island region varied by at least 4°C and possibly by as much as 10°C during Early Pliocene warm intervals (compared with ca 2°C for present day). Coupled with evidence from oxygen isotope data from bivalves, Early Pliocene Weddell Sea warm intervals were evidently much warmer than present, with summer sea temperatures probably exceeding 5°C. Morphological (growth-increment) and oxygen isotope data from bivalves in the marine interglacial Cockburn Island Formation (dated at 4.7 Ma) indicate little or no sea ice present, supporting the theory that Chlamys-like bivalves have retreated from the Antarctic as sea ice increased in the late Pliocene. We demonstrate that bivalve and bryozoan growth-related morphologies, interpreted in conjunction with stable oxygen and carbon isotope data, provide a powerful tool for tracking high latitude climate in the Pliocene.

  15. Progress report on the scientific data compilation and analyses in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica)

    OpenAIRE

    Teschke, Katharina; Bornemann, Horst; Bombosch, Annette; Brey, Thomas; Brtnik, Patricia; Burkhardt, Elke; Dorschel, Boris; Feindt-Herr, Helena; Gerdes, Dieter; Gutt, Julian; Hain, Stefan; Herata, Heike; Jerosch, Kerstin; Knust, Rainer; Kock, Karl-Hermann

    2013-01-01

    At the CCAMLR meeting in 2012, the Commission welcomed the offer of Germany to take the lead in developing a Weddell Sea MPA for consideration in 2014. Subsequently, the German Federal Ministry of Food, Agriculture and Consumer Protection tasked the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research to compile and analyse scientific data for identifying areas which require particular protection in the Weddell Sea. Work under this project started mid-April 2013. This prog...

  16. New data on Weddell seal (Leptonychotes weddellii colonies: A genetic analysis of a top predator from the Ross Sea, Antarctica.

    Directory of Open Access Journals (Sweden)

    Ighor Antunes Zappes

    Full Text Available In this paper, we studied the genetic variability in Weddell seal from colonies in Terra Nova Bay and Wood Bay, both sites located in the Ross Sea area, Antarctica. Two mitochondrial genes and one nuclear gene, with different mutation rates, were sequenced to investigate the haplotype diversity of the colonies and to test for a possible recent expansion. Fifteen microsatellites were used to analyze their genetic structure. Sequenced genes and microsatellites were also used to estimate the effective population size of the studied colonies and the Ross Sea seal population. The Ross Sea has a high density population of Weddel seals, with an estimated effective number of 50,000 females, and 1,341 individuals for the sampling area, possibly due to its high primary production. The colonies showed high diversity (Hd > 0.90 and many exclusive haplotypes (> 75%, likely a consequence of the surprisingly high site fidelity of Weddell seals, despite the proximity of the colonies. Nevertheless, there was low microsatellite differentiation between colonies, suggesting that they are part of a single larger population. Their expansion seemed to have started during the last glacial cycle (around 58,000 years ago, indicating that the Ross Sea seal populations have been present in the area for long time, probably due to the lack of hunting by humans and terrestrial predation. As a top predator, the role of Weddell seals in the Ross Sea ecology is crucial, and its demographic dynamics should be monitored to follow the future changes of such an important ecosystem.

  17. Physical and chemical data collected using bottle casts from the GENERAL SAN MARTIN in the Scotia Sea and Weddell Sea from 14 December 1963 to 11 January 1964 (NODC Accession 0000791)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and chemical data were collected using bottle casts in the Scotia Sea and Weddell Sea from the GENERAL SAN MARTIN. Data were collected from 14 December 1963...

  18. Spatio-temporal patterns in acoustic presence and distribution of Antarctic blue whales Balaenoptera musculus intermedia in the Weddell Sea

    OpenAIRE

    Thomisch, Karolin; Boebel, Olaf; Clark, CW; Hagen, W.; Spiesecke, Stefanie; Zitterbart, Daniel; Van Opzeeland, Ilse

    2016-01-01

    Distribution and movement patterns of Antarctic blue whales Balaenoptera musculus intermedia at large temporal and spatial scales are still poorly understood. The objective of this study was to explore spatio-temporal distribution patterns of Antarctic blue whales in the Atlantic sector of the Southern Ocean, using passive acoustic monitoring data. Multi-year data were collected between 2008 and 2013 by 11 recorders deployed in the Weddell Sea and along the Greenwich meridian. Antarctic blue ...

  19. Proposal for the establishment of a marine CCAMLR MPA in the Weddell Sea (Antarctica) – First conceptual outline

    OpenAIRE

    Teschke, Katharina; Dorschel, Boris; Gutt, Julian; Hain, Stefan; Hellmer, Hartmut; Jerosch, Kerstin; Knust, Rainer; Kock, Karl-Hermann; Schlüter, Michael; Siegel, Volker; Brey, Thomas

    2013-01-01

    In recent years, CCAMLR member states undertook substantial efforts to designate marine protected areas (MPAs) in the Southern Ocean. While MPA planning for six domains is underway, for three domains CCAMLR member states were asked to take the lead in MPA planning. At the CCAMLR meeting in 2012, the Commission welcomed the offer of Germany to take the lead in developing a Weddell Sea MPA for consideration in 2014. Subsequently, the German Federal Ministry of Food, Agriculture and Consumer Pro...

  20. Scientific background document in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica) – Version 2014

    OpenAIRE

    Teschke, Katharina; Bester, M. N.; Bornemann, Horst; Brandt, Angelika; Brtnik, Patricia; De Broyer, Claude; Burkhardt, Elke; Dieckmann, Gerhard; Flores, Hauke; Gerdes, Dieter; Griffiths, H. J.; Gutt, Julian; Hain, Stefan; Hellmer, Hartmut; Herata, Heike

    2014-01-01

    Germany intends to present the Scientific Committee the background document that provides the scientific basis for the evaluation of marine protected areas (MPAs) in the Weddell Sea. Please note, that the current state of the background document presents a comprehensive yet incomplete first version concerning chapters that have to be (further) developed or revised. The contents and structure of the document reflect also its main objectives, i.e. (i) to set out the general background and conte...

  1. Provenance Tracing of Glacial Sediment from the Foundation, Academy, and Recovery Ice Streams, Weddell Sea, Antarctica

    Science.gov (United States)

    Cirone, A.; Brachfeld, S. A.; Cortes, I.; Verhagen, C. M.; Williams, T.; Hemming, S. R.; Licht, K.; van de Flierdt, T.

    2016-12-01

    The Ronne-Filchner Ice Shelf is the second largest ice shelf in Antarctica and drains ice from both West and East Antarctica. This sector has the potential to generate significant sea level rise in the face of global climate change. This project seeks to advance our understanding of ice dynamics by "fingerprinting" ice streams that drain into the Ronne-Filchner Ice Shelf and gain insight into the bedrock composition beneath the Antarctic Ice Sheet. The first step is to develop tracers of glacial debris, which can be used to correlate ice rafted debris in the Weddell Sea with ice streams on land. Till samples were collected from moraines adjacent to the Foundation, Academy, and Recovery ice streams during a December 2014 field season, and marine sediment samples from the ice shelf edge were taken from surface sediment grabs and piston cores from the International Weddell Sea Ocean Expedition. This collaborative project is developing a comprehensive suite of tracers. The ongoing study presented here focuses on bulk elemental compositions, texture and composition of iron-oxide grains, and sediment magnetic properties of the till samples. Till from the northern margin of Recovery ice stream has high Al/Ti ratios (21-22) and high values of the chemical index of alteration (CIA 70 -71). However, till from the southern margin of Recovery ice stream has Al/Ti values of 13-15 and elevated Mn/Al and Fe/Al ratios. Academy till has the highest Al/Ti values (23-24) and the highest Fe/Ti values (9-10), while Foundation ice stream till has a greater range of Al/Ti ratios (15-21) and CIA values (61-70). Iron oxide grains in the coarse silt and sand fraction from both terrestrial and marine samples have been extracted to form polished grain mounts, which will be analyzed for grain texture and geochemistry. Sediment magnetic analyses include magnetic susceptibility, magnetic grain size, and remanence carrying abilities of bulk sediment and individual lithologies represented by the

  2. A High-Resolution Model of Water Mass Transformation and Transport in the Weddell Sea

    Science.gov (United States)

    Hazel, J.; Stewart, A.

    2016-12-01

    The ocean circulation around the Antarctic margins has a pronounced impact on the global ocean and climate system. One of these impacts includes closing the global meridional overturning circulation (MOC) via formation of dense Antarctic Bottom Water (AABW), which ventilates a large fraction of the subsurface ocean. AABW is also partially composed of modified Circumpolar Deep Water (CDW), a warm, mid-depth water mass whose transport towards the continent has the potential to induce rapid retreat of marine-terminating glaciers. Previous studies suggest that these water mass exchanges may be strongly influenced by high-frequency processes such as downslope gravity currents, tidal flows, and mesoscale/submesoscale eddy transport. However, evaluating the relative contributions of these processes to near-Antarctic water mass transports is hindered by the region's relatively small scales of motion and the logistical difficulties in taking measurements beneath sea ice.In this study we develop a regional model of the Weddell Sea, the largest established source of AABW. The model is forced by an annually-repeating atmospheric state constructed from the Antarctic Mesoscale Prediction System data and by annually-repeating lateral boundary conditions constructed from the Southern Ocean State Estimate. The model incorporates the full Filchner-Ronne cavity and simulates the thermodynamics and dynamics of sea ice. To analyze the role of high-frequency processes in the transport and transformation of water masses, we compute the model's overturning circulation, water mass transformations, and ice sheet basal melt at model horizontal grid resolutions ranging from 1/2 degree to 1/24 degree. We temporally decompose the high-resolution (1/24 degree) model circulation into components due to mean, eddy and tidal flows and discuss the geographical dependence of these processes and their impact on water mass transformation and transport.

  3. Carnivorous sponges (Cladorhizidae) of the deep Weddell Sea, with descriptions of two new species

    Science.gov (United States)

    Dressler-Allame, Melina; Göcke, Christian; Kersken, Daniel; Plotkin, Alexander; Janussen, Dorte

    2017-03-01

    This paper presents 29 sponges of the family Cladorhizidae Dendy, 1922 sampled at 18 different stations in the Weddell Sea, Antarctic during two expeditions of RV Polarstern, PS61 ANT-XIX/2 ANDEEP 2 in 2002 and PS67 ANT-XXII/3 ANDEEP 3 in 2005. Fourteen species from four genera have been registered - one species of Asbestopluma Topsent, 1901, five species of Chondrocladia Thomson, 1873, three species of Cladorhiza Sars, 1872 and five species of Lycopodina Lundbeck, 1905. Six species are endemics of the Southern Ocean. Four species were previously only known from the areas north of the Antarctic and our records of them are thereby new for this region. Two species of Lycopodina, Lycopodina rhabdostylophora sp. nov. and Lycopodina pediculifera sp. nov., are new to science. Our study has considerably expanded the data on diversity of Cladorhizidae in the Southern Ocean. About 27 cladorhizid species (18-19% of global cladorhizid diversity) are now recorded for this region, of which 56% are endemics.

  4. Unusual diatom layers in upper pleistocene sediments from the northern Weddell Sea

    Science.gov (United States)

    Jordan, R. W.; Priddle, J.; Pudsey, C. J.; Barker, P. F.; Whitehouse, M. J.

    1991-07-01

    A sediment core from Jane Basin, northern Weddell Sea, contains distinct bands, up to 3 cm thick, of well preserved diatom frustules, contrasting with the generally poor preservation of adjacent material. Most notably, the fragile diatom genus Corethron is abundant in the layers and found as whole valves, while in the remainder of the core is rare and valves are broken and corroded. Extrapolation from contemporary data on phytoplankton production and standing crop suggests that the silicon content of the diatom ooze layers is very much greater than could be expected from a single year's phytoplankton production sedimenting from a corresponding area of the water column. Assuming direct, quantitative sedimentation, it would have taken decades to centuries to accumulate 3 cm of diatom ooze. The preservation of these layer indicates that unusual conditions prevailed, so that diatom valves settled through the water column more-or-less unaltered and remained preserved in this state in the sediment. Mass sedimentation of a diatom bloom followed by rapid burial seems the most likely combination of circumstances that could have caused this. It is unlikely that this would have occurred consistently over a long period. Horizontal concentration must have taken place, and this is most likely to have been associated with a physical feature of the water column such as an eddy or "chimney", which entrained phytoplankton biomass from a wide area of the surface mixed layer and caused it to sediment to a smaller area of the seabed.

  5. Transport and structure of the Weddell Gyre

    Directory of Open Access Journals (Sweden)

    E. Fahrbach

    1994-08-01

    Full Text Available A cyclonic gyre controls the advection of source waters into the formation areas of bottom water in the southern and western parts of the Weddell Sea and the subsequent transport of modified water masses to the north. Determination of the structure of the Weddell Gyre and of the associated transports was one of the objectives of the "Weddell Gyre Study" which began in September 1989 and ended in January 1993. The collected data set comprises records of moored current meters and profiles of temperature and salinity distributed along a transect between the northern tip of the Antarctic Peninsula and Kapp Norvegia. The circulation pattern on the transect is dominated by stable boundary currents of several hundred kilometers width at the eastern and western sides of the basin. They are of comparable size on both sides and provide nearly 90% of the volume transport of the gyre which amounts to 29.5 Sv. In the interior, a weak anticyclonic cell of 800 km diameter transports less than 4 Sv. Apart from the continental slopes, the near-bottom currents flow at some locations in an opposite direction to those in the water column above, indicating a significant baroclinic component of the current field. The intensity of the boundary currents is subject to seasonal fluctuations, whereas in the interior, time scales from days to weeks dominate. The large-scale circulation pattern is persistent during the years 1989 to 1991. The heat transport into the southern Weddell Sea is estimated to be 3.48×1013 W. This implies an equivalent heat loss through the sea surface of 19 W m-2, as an average value for the area south of the transect. The derived salt transport is not significantly different from zero; consequently, the salt gain by sea ice formation has to compensate almost entirely the fresh water gain from the melting ice shelves and from precipitation. Estimation of water mass formation rates from the thermohaline differences of the inflow and outflow

  6. Transport and structure of the Weddell Gyre

    Directory of Open Access Journals (Sweden)

    E. Fahrbach

    Full Text Available A cyclonic gyre controls the advection of source waters into the formation areas of bottom water in the southern and western parts of the Weddell Sea and the subsequent transport of modified water masses to the north. Determination of the structure of the Weddell Gyre and of the associated transports was one of the objectives of the "Weddell Gyre Study" which began in September 1989 and ended in January 1993. The collected data set comprises records of moored current meters and profiles of temperature and salinity distributed along a transect between the northern tip of the Antarctic Peninsula and Kapp Norvegia. The circulation pattern on the transect is dominated by stable boundary currents of several hundred kilometers width at the eastern and western sides of the basin. They are of comparable size on both sides and provide nearly 90% of the volume transport of the gyre which amounts to 29.5 Sv. In the interior, a weak anticyclonic cell of 800 km diameter transports less than 4 Sv. Apart from the continental slopes, the near-bottom currents flow at some locations in an opposite direction to those in the water column above, indicating a significant baroclinic component of the current field. The intensity of the boundary currents is subject to seasonal fluctuations, whereas in the interior, time scales from days to weeks dominate. The large-scale circulation pattern is persistent during the years 1989 to 1991. The heat transport into the southern Weddell Sea is estimated to be 3.48×1013 W. This implies an equivalent heat loss through the sea surface of 19 W m-2, as an average value for the area south of the transect. The derived salt transport is not significantly different from zero; consequently, the salt gain by sea ice formation has to compensate almost entirely the fresh water gain from the melting ice shelves and from precipitation. Estimation of water mass formation rates from the thermohaline differences of the

  7. Temporal variation in isotopic composition and diet of Weddell seals in the western Ross Sea

    Science.gov (United States)

    Goetz, Kimberly T.; Burns, Jennifer M.; Hückstӓdt, Luis A.; Shero, Michelle R.; Costa, Daniel P.

    2017-06-01

    Weddell seals (Leptonychotes weddellii) are important predators in the Antarctic marine ecosystem, yet little is known about their diet. Previous studies have used scat and stomach content analyses to examine Weddell seal diet, however, these methods are biased towards prey with indigestible hard parts. To provide a more complete picture of their diet, we analyzed the stable isotope composition (δ13C and δ15N values) of red blood cells (RBC, n=96, representing a time scale of weeks to months) and vibrissae (n=45, representing months to a year) collected over a three year period (2010-2012). Our objectives were to (1) examine isotopic variation in relation to Weddell seal mass, sex, season, location, percent lipid, and age, and (2) quantify the contribution of prey items to overall diet. Body mass was a significant predictor of δ13C and δ15N values for both tissues, though the strength and direction of the relationship varied by year. The prey group consisting of Pleurogramma antarcticum and Trematomus newnesi was found to be an important dietary component, but its proportional contribution to Weddell seal diet varied with the timeframe represented by each tissue type [median RBC (range): 59.2% (40.2-8 1.1%); median mean vibrissae (range): 69.3% (43.9-89.6%)]. Results from mixing models ran for each seal indicate individual variation in diet. Overall, this study presents novel information on the isotopic variation and diet of Weddell seals over two time scales and provides insight into the feeding ecology of an important Antarctic predator.

  8. 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

    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)

  9. INFLUENCE OF PHYSICAL AND BIOLOGICAL PROCESSES ON THE CONCENTRATION OF O-2 AND CO2 IN THE ICE-COVERED WEDDELL SEA IN THE SPRING OF 1988

    NARCIS (Netherlands)

    BOUQUEGNEAU, JM; GIESKES, WWC; KRAAY, GW; LARSSON, AM

    In October and November 1988, measurements of oxygen and total dissolved inorganic carbon (TCO2) concentrations were made in the northwestern Weddell Sea to the south and north of the marginal ice edge, in order to estimate the relative importance, regarding their variations, of both biological

  10. Climatología de la variabilidad espacial de la concentración de hielo en los mares de Bellingshausen, Amundsen y Weddell Climatology of sea ice concentration spatial variability over Bellingshausen, Amundsen and Weddell Seas

    Directory of Open Access Journals (Sweden)

    Rosa H. Compagnucci

    2005-12-01

    ártica, muestran un cambio de comportamiento ocurrido a fines de los años 80s, en que los mares de Amundsen y Bellingshausen pasaron de tener mayores a menores concentraciones de hielo marino. La distribución espacial de ACHM durante las fases maduras tanto de El Niño muestra una gran variabilidad entre eventos y en algunos casos tiene comportamiento opuesto para diferentes eventos. Lo mismo ocurre para La Niña. La influencia del ciclo El Niño/Oscilación del Sur es clara solo para el invierno que sigue a la fase madura estival del El Niño o La Niña.In this paper the most frequent spatial patterns of sea ice concentration anomalies (SICA over the Amundsen, Bellingshausen and Weddell Seas have been obtained from monthly mean values of sea ice concentrations provided by the Scanning Multichannel Microwave Radiometer and the Special Sensor Microwave/Imager of NASA Goddard Space Flight Center for the period 1979 2000. Using analysis of Principal Components (PCs in T-Mode rotated Varimax, six PCs were obtained. Therefore, a total of 12 patterns were found with six in direct mode (SICA of the same sign that the PC and six in inversely (SICA of opposite sign to the PC, that classify 95.5 % of the monthly fields. Three PCs describe the most frequent winter-spring cases (period with major concentration and expansion of sea ice and three PCs correspond to summer-autumn (minor concentration and retraction of the field of ice. Winter-spring months have mainly situations close to the first and second PCs. The 2°PC shows a 30 ° counter wise rotation with respect to the 1°CP and both present dipole anomalies between the seas at both sides of the Antarctic Peninsula. These two components display a recurrence of approximately 4 years in which alternatively the exterior region of the Weddell Sea has conditions of sea ice above the mean values meanwhile, in the north of the Amundsen Sea, the anomalies are negative and vice versa. The most frequent condition with an annual summer - autumn

  11. Morphology and Ecology of Diatoms in Sea Ice from the Weddell Sea,

    Science.gov (United States)

    1984-02-01

    pack ice two physical mechanisms to account for the high samples with illustrative scanning electron micro- concentrations of algae in young, thin ice...I is ohs il h, t4 4 l’) s 4 I0 iho cu ) d 2e sn o N o 9 (2.6. 0’( 20 e0 m Ith tei.alls (2.3 i ) j bl1 t klhdruh Ii h Ie c,1r I t hsl! f, r . i hich s...Comparison of the size ranges reported Two mechanisms for incorporation of algae into in the literature with our measurements shows newly forming sea ice

  12. Density of pack-ice seals and penguins in the western Weddell Sea in relation to ice thickness and ocean depth

    Science.gov (United States)

    Flores, Hauke; Haas, Christian; van Franeker, Jan Andries; Meesters, Erik

    2008-04-01

    Aerial band transect censuses were carried out parallel with ice thickness profiling surveys in the pack ice of the western Weddell Sea during the ISPOL (Ice Station POLarstern) expedition of R.V. Polarstern from November 2004 to January 2005. Three regions were surveyed: the deep sea of the Weddell Sea, a western continental shelf/slope region where R.V. Polarstern passively drifted with an ice floe (ISPOL), and a northern region (N). Animal densities were compared among regions and in relation to bathymetry and ice thickness distribution. Crabeater seals Lobodon carcinophaga were the most abundant species in all three regions. Their density was significantly lower in the deep sea (0.50 km -2) than in the ISPOL (1.00 km -2) and northern regions (1.21 km -2). Weddell seals Leptonychotes weddellii were not sighted in the deep-sea region, their density elsewhere ranging from 0.03 (N) to 0.08 km -2 (ISPOL). Leopard seals Hydrurga leptonyx were observed in all three areas, but could only be quantified in the deep-sea (0.05 km -2) and northern regions (0.06 km -2). The abundance of emperor penguins Aptenodytes forsteri was markedly higher in the northern (0.75 km -2) than in the ISPOL (0.13 km -2) and the deep-sea region (not quantified). Crabeater seal density was significantly related to ocean depth and modal ice thickness.

  13. Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from NATHANIEL B. PALMER, ICE ISLANDS and AKADEMIK FYODOROV in the Weddell Sea from 1992-02-02 to 1992-06-18 (NODC Accession 9500052)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and Rosette Bottle sampling was done from helicopter, ship, and ice island. The data were collected in Weddell Sea as...

  14. The gastropod-symbiotic sea anemone genus Isosicyonis Carlgren, 1927 (Actiniaria: Actiniidae: a new species from the Weddell Sea (Antarctica that clarifies the taxonomic position of the genus

    Directory of Open Access Journals (Sweden)

    Estefanía Rodríguez

    2008-03-01

    Full Text Available A second species of the sea anemone genus Isosicyonis is described and illustrated from 16 specimens collected in the Weddell Sea (Antarctica on the Polarstern cruises ANT XVII/3, ANT XXI/2 and ANT XXIII/8. Isosicyonis striata n. sp. is easily distinguishable externally from the other species of the genus Isosicyonis alba by its pattern: white longitudinal stripes on the column, oral disc, and tentacles. It is also distinguished by internal features including the retractor muscles, parietobasilar muscles, marginal sphincter muscles, number of mesenteries, and cnidae. The genus Isosycionis is currently only known from the Southern Ocean. Both species of Isosicyonis live in association with a gastropod, with a single sea anemone occupying almost the whole shell of its gastropod host. The description of this new species, and our re-examination of Isosicyonis alba, resolves the controversial higher taxonomic position of the genus, confirming its placement within the Endomyaria.

  15. Investigation of carbon dioxide in the South Atlantic and northern Weddell Sea areas (WOCE Sections A-12 and A-21) during the METEOR expedition 11/5, January--March 1990

    Energy Technology Data Exchange (ETDEWEB)

    Chipman, D.W.; Takahashi, Taro; Breger, D.; Sutherland, S.C.

    1991-12-01

    This report summarizes the results of investigation the oceanographic expedition aboard the F/S METEOR in South Atlantic Ocean including the Drake Passage, the northern Weddell Sea and the eastern South Atlantic during the austral summer of January through March 1990. The total CO{sub 2} concentration in about 1300 seawater samples and CO{sub 2} partial pressure (pCO{sub 2}) in about 870 seawater samples collected at 77 stations were determined aboard the ship using a coulometer and equilibrator/gas chromatograph system. The temperature, salinity, dissolved oxygen and nutrient salt data presented in this report were determined by other participants of the expedition including the members of the Oceanographic Data Facility of the Scripps Institution of Oceanography, Argentine Hydrographic Office and German institutions.

  16. Investigation of carbon dioxide in the South Atlantic and northern Weddell Sea areas (WOCE Sections A-12 and A-21) during the METEOR expedition 11/5, January--March 1990. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Chipman, D.W.; Takahashi, Taro; Breger, D.; Sutherland, S.C.

    1991-12-01

    This report summarizes the results of investigation the oceanographic expedition aboard the F/S METEOR in South Atlantic Ocean including the Drake Passage, the northern Weddell Sea and the eastern South Atlantic during the austral summer of January through March 1990. The total CO{sub 2} concentration in about 1300 seawater samples and CO{sub 2} partial pressure (pCO{sub 2}) in about 870 seawater samples collected at 77 stations were determined aboard the ship using a coulometer and equilibrator/gas chromatograph system. The temperature, salinity, dissolved oxygen and nutrient salt data presented in this report were determined by other participants of the expedition including the members of the Oceanographic Data Facility of the Scripps Institution of Oceanography, Argentine Hydrographic Office and German institutions.

  17. Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

    Science.gov (United States)

    Richards, P. G.; Meier, R. R.; Chen, Shih-Ping; Drob, D. P.; Dandenault, P.

    2017-06-01

    This paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30° to 120°W geographic longitude and 50° to 75°S geographic latitude at solar minimum between 2007 and 2010. This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer. This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data. It is shown that the commonly accepted explanation that the WSA is related to the magnetic field declination and inclination effects on the neutral wind does not explain the longitudinal variation of the electron density. Rather, longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the WSA. These longitudinal wind and density changes are attributed to the varying latitudinal distance from the auroral zone energy input. No contributions from the plasmasphere or other sources are required. Furthermore, it is shown that a widely used empirical thermosphere density model overestimates the longitudinal changes in the WSA region.type="synopsis">type="main">Plain Language SummaryThis paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30° to 120°W geographic longitude and 50° to 75°S geographic latitude at solar minimum between 2007 and 2010. This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer. This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data. It is shown that the commonly accepted explanation that the WSA is related to the

  18. Air-ice drag coefficients in the western Weddell Sea: 2. A model based on form drag and drifting snow

    Science.gov (United States)

    Andreas, Edgar L.

    1995-03-01

    In part 1 (Andreas and Claffey, this issue) we observed some characteristics of the neutral stability air-ice drag coefficient at a reference height of 10 m (CDN10) that had not been documented before. Our main conclusion was that wind-driven snow continually alters the sea ice surface; the resulting snowdrifts determine how large CDN10 is. In particular, part 1 reported three observations that I would like to explain. (1) CDN10 is near 1.5×10-3 when the wind is well aligned with the drifted snow. (2) CDN10 is near 2.5×10-3 when the wind makes a large angle with the dominant orientation of the snowdrifts. (3) CDN10 can increase by 20% if, after being well aligned with the drift patterns, the mean wind direction shifts by as little as 20°. To investigate this behavior of CDN10 here I adapt a model developed by Raupach (1992) that partitions the total surface stress into contributions from form drag and skin friction. An essential part of this development was extending Raupach's model to the more complex geometry of sastrugi-like roughness elements. Assuming that 10-cm high sastrugi cover 15% of the surface, this physically based model reproduces the three main observations listed above. Thus the model seems to include the basic physics of air-ice momentum exchange. The main conclusion from this modeling is that 10-cm, sastrugilike snowdrifts, rather than pressure ridges, sustain most of the form drag over compact sea ice in the western Weddell Sea. Secondly, the modeling suggests that skin friction accounts for about 60% of the surface stress when the wind is well aligned with the sastrugi; but when the wind is not well aligned, form drag accounts for about 80% of the stress. The sastrugi are thus quite effective in streamlining the surface.

  19. On the effect of topography and wind on warm water inflow—An idealized study of the southern Weddell Sea continental shelf system

    Science.gov (United States)

    Daae, K.; Hattermann, T.; Darelius, E.; Fer, I.

    2017-03-01

    An idealized eddy-resolving numerical model, with topographic features common to the southern Weddell Sea, is constructed to study mechanisms through which warm deep water enters a wide continental shelf with a trough. The open ocean, represented by a 1700 m deep channel, is connected to a 400 m deep shelf with a continental slope. The shelf is narrow (50 km) in the east but widens to 300 km at the center of the model domain. Over the narrow shelf, the slope front is balanced by wind-driven Ekman downwelling and counteracting eddy overturning, favoring on-shelf transport of warm water in summer scenarios when fresher surface water is present. Over the wide shelf, the Ekman downwelling ceases, and the mesoscale eddies relax the front. Inflow of warm water is sensitive to along-shelf salinity gradients and is most efficient when denser water over the wide shelf favors up-slope eddy transport along isopycnals of the V-shaped slope front. Inflow along the eastern side of the trough cannot penetrate the sill region due to potential vorticity constraints, while along the western trough flank, eddy-induced inflow crosses the sill and reaches the ice front. The warm inflow into the trough is sensitive to the density of the outflowing dense shelf water. For weaker winds, absence of the dense water outflow leads to a reversal of the trough circulation and a strong inflow of warm water, while for stronger winds, baroclinic effects become less important and the inflow is similar to experiments including dense water outflow.

  20. Long-term observations of theWeddell Sea Anomaly based on the Swarm, CHAMP and DEMETER missions

    Science.gov (United States)

    Slominska, E.

    2016-12-01

    Normalized density difference index (INDD) was introduced for the purpose of detection of such phenomena as the Weddell Sea Anomaly (WSA). With this basic approach, we are capable of identifying spatial and temporal occurrence of anomalies exhibiting reversed diurnal cycle, characterized by greater ionospheric plasma densities observed in the post-sunset hours, when compared to day-time ones. Development of the WSA together with similar phenomenon observed in the Northern Hemisphere, named as the Mid-latitude Summer Nighttime Anomaly is documented with three satellite missions Swarm, DEMETER, and CHAMP. Since the generation of discussed anomalies is still an open issue, multi-mission and multi-instrumental observations at various altitudes should improve our understanding of the phenomena, and verify the role of several potential mechanisms used for explanation. Among mentioned mechanisms, combined result of thermospheric wind, solar photo-ionization, and the local magnetic field configuration is taken as a most comprehensive explanation. Analysis based on long-term trends of observations from three missions and six satellites are aimed at the proper parametrization of the phenomenon. Using spatial gradients in the magnetic field components derived from Swarm A/B/C magnetometers, we discuss longitudinal distributions and variations of anomalies. The study quantifies hemispheric differences between two anomalies, as well as temporal trends concerning the solar cycle.

  1. Metal enrichment experiments in the Weddell-Scotia Seas: Effects of iron and manganese on various communities

    Energy Technology Data Exchange (ETDEWEB)

    Buma, A.G.J.; Barr, H.J.W. de; Nolting, R.F.; Bennekom, A.J. van (Netherlands Inst. for Sea Research, Den Burg (Netherlands))

    1991-12-01

    During the European Polarstern Study (EPOS 1988/1989) in the Weddell and Scotia Seas, five series of metal enrichment experiments were carried out with natural plankton communities under ultraclean conditions. Despite a clear stimulation of growth by the addition of Fe, control bottles also showed rapid buildup of Chl a and complete utilization of a major nutrient within 2 weeks, indicating nonlimiting ambient Fe levels. Effects of Mn additions were less pronounced or absent, whereas extra additions of Zn and Cu in one experiment showed little or no effect. The species composition of the plankton community, monitored by HPLC pigment analysis and microscopic observations, changed in favor of diatoms when Fe was added. The addition of Fe also caused an increase in microzooplankton densities and concentrations of pigment breakdown products. However, metal-mediated shifts in the plankton community were minor compared to major changes resulting from incubation. Changes were most pronounced in experiments where microzooplankton was strongly developed, presumably as a result of excluding mesozooplankton from the bottles. Fe had an impact on plankton growth and species composition, but other factors seem to responsible for keeping phytoplankton productivity far from its potential in these Antarctic waters.

  2. Jurassic high heat production granites associated with the Weddell Sea rift system, Antarctica

    Science.gov (United States)

    Leat, Philip T.; Jordan, Tom A.; Flowerdew, Michael J.; Riley, Teal R.; Ferraccioli, Fausto; Whitehouse, Martin J.

    2018-01-01

    The distribution of heat flow in Antarctic continental crust is critical to understanding continental tectonics, ice sheet growth and subglacial hydrology. We identify a group of High Heat Production granites, intruded into upper crustal Palaeozoic metasedimentary sequences, which may contribute to locally high heat flow beneath the West Antarctic Ice Sheet. Four of the granite plutons are exposed above ice sheet level at Pagano Nunatak, Pirrit Hills, Nash Hills and Whitmore Mountains. A new Usbnd Pb zircon age from Pirrit Hills of 178.0 ± 3.5 Ma confirms earlier Rbsbnd Sr and Usbnd Pb dating and that the granites were emplaced approximately coincident with the first stage of Gondwana break-up and the developing Weddell rift, and 5 m.y. after eruption of the Karoo-Ferrar large igneous province. Aerogeophysical data indicate that the plutons are distributed unevenly over 40,000 km2 with one intruded into the transtensional Pagano Shear Zone, while the others were emplaced within the more stable Ellsworth-Whitmore mountains continental block. The granites are weakly peraluminous A-types and have Th and U abundances up to 60.7 and 28.6 ppm respectively. Measured heat production of the granite samples is 2.96-9.06 μW/m3 (mean 5.35 W/m3), significantly higher than average upper continental crust and contemporaneous silicic rocks in the Antarctic Peninsula. Heat flow associated with the granite intrusions is predicted to be in the range 70-95 mW/m2 depending on the thickness of the high heat production granite layer and the regional heat flow value. Analysis of detrital zircon compositions and ages indicates that the high Th and U abundances are related to enrichment of the lower-mid crust that dates back to 200-299 Ma at the time of the formation of the Gondwanide fold belt and its post-orogenic collapse and extension.

  3. Simulating pancake and frazil ice growth in the Weddell Sea: A process model from freezing to consolidation

    Science.gov (United States)

    Doble, Martin J.

    2009-09-01

    Processes controlling the formation and transformation of frazil to pancake ice are examined using data from an array of drifting buoys deployed at the advancing ice edge in the Weddell Sea. A simple thermodynamic model is coupled to the buoy dynamics and to an ice redistribution model to determine the influence of deformation, thermodynamics, and mechanical scavenging, incorporating frazil crystals from the surrounding slick into the pancakes, on the partitioning of ice volume between frazil and pancakes. Ice production was examined from the time the buoys were deployed until the frazil/pancake cover consolidated into the more familiar pack ice. The model reproduced the expected ice cover thickness at consolidation (60 cm). Rafting was the dominant contribution to thickening in the region owing to large-scale compression of the initial area by northerly winds from passing low-pressure weather systems, which are rather typical in the region. High-resolution positional forcing from the buoys (20-min intervals) doubled the contribution of mechanical scavenging to final pancake thickness compared to the coarser (2-h) result, owing to the larger path length that the pancakes traverse through the frazil slick, and produced a significantly larger volume of ice in the pancake phase. The ice cover generated at consolidation was approximately twice as thick as would have formed by the more familiar congelation ice growth under the same forcing, reinforcing the importance of correctly parameterizing the early stages of ice formation in the Antarctic. The study highlighted uncertainties in the effect of the frazil/pancake cover on ocean-atmosphere heat exchange, both in terms of the area contributing to ice production and the effect on turbulent exchange coefficients. Further work placing the empirical parameters into a more constrained physical framework and introducing wave properties is suggested.

  4. Translation and rotation of small crustal blocks in the southernmost Atlantic-Weddell Sea region prior to seafloor spreading: in search of a mechanism

    Science.gov (United States)

    Dalziel, I. W. D.; Norton, I. O.; Lawver, L. A.; Lavier, L.; Davis, J. K.; Gahagan, L.

    2016-12-01

    Geological and paleomagnetic data indicate that initial fragmentation of the Gondwanaland supercontinent in the southernmost Atlantic-Weddell Sea region involved translation and rotation of two small crustal blocks. The Falkland/Malvinas block on the South American plate (F/M) and the Ellsworth-Whitmore mountains block in West Antarctica (EWM) both contain segments of the earliest Mesozoic Gondwana fold belt. The blocks originated in the Natal embayment between the Cape Mountains of southernmost Africa and the Pensacola Mountains of the East Antarctic craton margin. Shortly after emplacement of the Karoo-Ferrar large igneous province (LIP) at ca. 182Ma, the F/M block was rotated clockwise 150 ° and the EWM block counter¬clockwise 90°, while both were translated several hundred kilometers towards the Panthalassic/Pacific Ocean. As indicated by absence of shortening in the sedimentary basins of the F/M Plateau and Weddell embayment, the motions of the crustal blocks relative to the major continents happened during extreme extension accompanied by widespread silicic magmatism that preceded seafloor spreading. We propose a new reconstruction of the Gondwana craton margin, suggesting an original embayment between the Kalahari and East Antarctic cratons, and subsequent mirror-image clockwise (South America-F/M) and counterclockwise (Antarctic Peninsula-EWM) rotations prior to seafloor spreading in the Weddell Sea and South Atlantic.What geodynamic processes were involved in the significant rotations and translations of continental lithosphere prior to ocean basin formation? Our conclusion, based on the geologic and geophysical data and on geodynamic modeling, is that the motions were driven by the distributed crustal thinning of warm continental lithosphere and by mantle flow towards a retreating Panthalassic margin subduction zone associated with the formation of the Karoo-Ferrar Large Igneous Province between the East Antarctic, Kalahari and Rio de la Plata cratons.

  5. Early results from combined historic chlorofluorocarbon and first sulphur hexafluoride measurements in the Weddell Sea - variability of ventilation rates and anthropogenic carbon

    Science.gov (United States)

    Huhn, O.; Rhein, M.; Bulsiewicz, K.

    2012-04-01

    The Weddell Sea is a key area for the formation of deep and bottom water and, hence, a major driver of the deep part of the global ocean's conveyor belt. Furthermore, it provides an important sink for atmospheric gases like anthropogenic carbon. Its sensitivity to changing atmospheric conditions is under discussion. During the last three decades time series of anthropogenic transient tracer measurements (chlorofluorocarbons, CFCs) were obtained on a section crossing the Weddell Basin from the northern tip of the Antarctic Peninsula to Cape Norwegia and along the Prime Meridian from the Antarctic Continent to the Mid Atlantic Ridge (1984-2008). On our most recent RV POLARSTERN expedition from November 2010 to February 2011 we obtained for the first time sulphur hexafluoride (SF6) measurements in addition to CFCs in that area. The onset of the atmospheric SF6 history starts some decades after the CFCs, and the increase of SF6 in the atmosphere is steeper. The combination of CFC and SF6 may, hence, provide a better constraint for the quantification of very recently ventilated deep and bottom water and for the estimate of transport time scales or transit time distributions (TTDs). We discuss that new CFC and SF6 data set in comparison to the historic CFC data and show early results from our analysis. We use the extended CFC time series combined with the additional tracer SF6 to determine TTDs, from which we assess the ventilation rates of deep and bottom water and estimate the related content of anthropogenic carbon and their temporal variability in the Weddell Sea during the last three decades.

  6. Coping with the loss of large, energy-dense prey: a potential bottleneck for Weddell Seals in the Ross Sea.

    Science.gov (United States)

    Salas, Leo; Nur, Nadav; Ainley, David; Burns, Jennifer; Rotella, Jay; Ballard, Grant

    2017-01-01

    Extraction of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea began in 1997, following a management plan that targets the largest fish with a goal of reducing the spawning biomass by 50% over 35 yr. We investigate the potential long-term consequences of the reduced availability of this prey for Weddell seals (Leptonychotes weddellii). Energy demands in seals are acute, especially immediately following lactation, when females must recover substantial mass and cope with molting costs. We tested the hypothesis that toothfish are critically important for adult female seals during this period. Toothfish body mass is three orders of magnitude greater, and its energy density nearly double that of the most common seal prey, Antarctic silverfish (Pleuragramma antarcticum). Reduction or elimination of toothfish consumption could impair a female's ability to sufficiently recover and successfully produce a pup in the following pupping season. Our goals are to (1) illustrate mechanisms and conditions whereby toothfish depletion might plausibly affect seal population trends; (2) identify measurable parameters of the seals' ecology that may help better understand the potential negative impact of toothfish depletion on seal populations; and (3) promote a precautionary management approach for the fishery that includes monitoring of seal populations We constructed a set of inter-linked models of seal diving behavior, physiological condition, and demography based on existing information. We evaluate the effect of the following factors on seal mass recovery and intrinsic population growth rates: fishery depletion rate, daily diving limits, probability of a successful dive, and body mass recovery target. We show that loss of toothfish has the greatest potential impact on seal populations' growth rate. Under some scenarios, populations may decrease at >10% per year. Critical parameters to better understand fishery impacts include prevalence and size of toothfish in the seals

  7. The macro- and megabenthic fauna on the continental shelf of the eastern Amundsen Sea, Antarctica

    Science.gov (United States)

    Linse, Katrin; Griffiths, Huw J.; Barnes, Dave KA; Brandt, Angelika; Davey, Niki; David, Bruno; De Grave, Sammy; d‧Udekem d‧Acoz, Cédric; Eléaume, Marc; Glover, Adrian G.; Hemery, Lenaïg G.; Mah, Christopher; Martín-Ledo, Rafael; Munilla, Tomás; O‧Loughlin, Mark; Pierrat, Benjamin; Saucède, Thomas; Sands, Chester J.; Strugnell, Jan M.; Enderlein, Peter

    2013-10-01

    In 2008 the BIOPEARL II expedition on board of RRS James Clark Ross sailed to the eastern Amundsen Sea Embayment and Pine Island Bay, one of the least studied Antarctic continental shelf regions due to its remoteness and ice cover. A total of 37 Agassiz trawls were deployed at depth transects along the continental and trough slopes. A total of 5469 specimens, belonging to 32 higher taxonomic groups and more than 270 species, were collected. Species richness per station varied from 1 to 55. The benthic assemblages were dominated by echinoderms and clearly different to those in the Ross, Scotia and Weddell seas. Here we present the macro- and megafaunal assemblage structure, its species richness and the presence of several undescribed species.

  8. Elements for a revision and notes on bionomy of the Cumacea (Crustacea: Peracarida) of the Weddell Sea (Antarctica). : Material collected by the Expedition ANTARKTIS-VIII/5 of R.V. “Polarstern” 1989/90

    NARCIS (Netherlands)

    Petrescu, I.; Wittmann, K.J.

    2003-01-01

    Among 26 species of Antarctic Cumacea sampled during the southern summer 1989/90 from benthic habitats in the Weddell Sea, four are described as new to science: Campylaspis ledoyeri spec. nov., Hemilamprops bacescui spec. nov., Paralamprops racovitzai spec. nov., and Leptostylis weddelli spec. nov.

  9. Community structure of under-ice fauna in relation to winter sea-ice habitat properties from the Weddell Sea

    NARCIS (Netherlands)

    David, Carmen; Schaafsma, F.L.; Franeker, van J.A.; Lange, Benjamin; Brandt, A.; Flores, H.

    2017-01-01

    Climate change-related alterations of Antarctic sea-ice habitats will significantly impact the interaction of ice-associated organisms with the environment, with repercussions on ecosystem functioning. The nature of this interaction is poorly understood, particularly during the critical period of

  10. Influences of sea ice on eastern Bering Sea phytoplankton

    Science.gov (United States)

    Zhou, Qianqian; Wang, Peng; Chen, Changping; Liang, Junrong; Li, Bingqian; Gao, Yahui

    2015-03-01

    The influence of sea ice on the species composition and cell density of phytoplankton was investigated in the eastern Bering Sea in spring 2008. Diatoms, particularly pennate diatoms, dominated the phytoplankton community. The dominant species were Grammonema islandica (Grunow in Van Heurck) Hasle, Fragilariopsis cylindrus (Grunow) Krieger, F. oceanica (Cleve) Hasle, Navicula vanhoeffenii Gran, Thalassiosira antarctica Comber, T. gravida Cleve, T. nordenskiöeldii Cleve, and T. rotula Meunier. Phytoplankton cell densities varied from 0.08×104 to 428.8×104 cells/L, with an average of 30.3×104 cells/L. Using cluster analysis, phytoplankton were grouped into three assemblages defined by ice-forming conditions: open water, ice edge, and sea ice assemblages. In spring, when the sea ice melts, the phytoplankton dispersed from the sea ice to the ice edge and even into open waters. Thus, these phytoplankton in the sea ice may serve as a "seed bank" for phytoplankton population succession in the subarctic ecosystem. Moreover, historical studies combined with these results suggest that the sizes of diatom species have become smaller, shifting from microplankton to nannoplankton-dominated communities.

  11. Particle tracking in the eastern Irish Sea

    Science.gov (United States)

    Wolf, Judith; Amoudry, Karen; Phillips, Hazel; Brown, Jenny

    2017-04-01

    The unstructured grid finite volume community ocean model (FVCOM) has been applied to the west coast of the UK, in order to examine the circulation and transport in the eastern Irish Sea. Tides, freshwater river discharge and meteorological forcing for the year 2008 were used to force the baroclinic hydrodynamic circulation. The hydrodynamics of the Irish Sea are largely governed by the semidiurnal tide, which has a tidal range reaching 10m at Liverpool is the eastern Irish Sea. Tidal currents reach 1 ms-1 over the majority of the area, which means that much of Irish Sea is vertically well-mixed throughout the year period, with a few areas affected by seasonal stratification, such as the cyclonic gyre in the deep channel off Ireland in the western Irish Sea which experiences thermal stratification in summer. In Liverpool Bay, horizontal density gradients, created through freshwater influence from estuaries along the coastline interact with the strong tidal current to produce a phenomenon known as strain-induced periodic stratification (SIPS). There are water quality concerns due to the tendency to eutrophication, as the area is often exposed to industrial pollution and excess nutrients from effluent waters and rivers. There is also concern about the fate of radioactive materials discharged from the Sellafield nuclear reprocessing plant since 1952. In addition to the present discharges from the site, it has been estimated that it is likely that all of the americium and plutonium and around 10% of the caesium entering the Irish Sea were originally assimilated into deposits of silt and mud sediments; this material may be regarded as a considerable potential source of radionuclides. Determining suspended sediment pathways in this region is important in order to identify potential areas vulnerable to deposition of radioactive material, particularly as radionuclide uptake onto sediments takes place in the offshore 'mud patch' before returning to the coast to be deposited

  12. New and little-known Komokiacea (Foraminifera) from the bathyal and abyssal Weddell Sea and adjacent areas

    DEFF Research Database (Denmark)

    Gooday, A.J.; Kamenskaya, O.E.; Cedhagen, Tomas

    2007-01-01

    Based on samples from the south-east Atlantic and Southern Ocean collected during the ANDEEP III campaign we describe three new species, Ipoa pennata sp. nov., Septuma stellata sp. nov. and Skeletonia variabilis gen. et sp. nov., of the enigmatic deep-sea foraminiferan superfamily Komokiacea. A f...

  13. Transparent exopolymer particle (TEP) dynamics in the eastern Mediterranean Sea

    National Research Council Canada - National Science Library

    E. Bar-Zeev; T. Berman; E. Rahav; G. Dishon; B. Herut; N. Kress; I. Berman-Frank

    2011-01-01

    Depth and spatial distribution patterns of transparent exopolymer particles (TEP) were measured during 2 east to west cruise transects across the ultra-oligotrophic Levantine basin, eastern Mediterranean Sea...

  14. Acoustic tomography experiment in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Murty, T.V.R.; Somayajulu, Y; Saran, A; Navelkar, G.S.; Almeida, A; Fernando, V.; Murty, C.S.

    An acoustic transmission experiment was conducted in the eastern Arabian Sea along 12.5 degrees N latitude for a duration of ten days (2-12 May, 1993), with two transceiver systems deployed on deep sea moorings, separated by a range of 270.92 km...

  15. Problems of the active tectonics of the Eastern Black Sea

    Science.gov (United States)

    Javakhishvili, Z.; Godoladze, T.; Dreger, D. S.; Mikava, D.; Tvaliashvili, A.

    2016-12-01

    The Black Sea Basin is the part of the Arabian Eurasian Collision zone and important unit for understanding the tectonic process of the region. This complex basin comprises two deep basins, separated by the mid-Black Sea Ridge. The basement of the Black Sea includes areas with oceanic and continental crust. It was formed as a "back-arc" basin over the subduction zone during the closing of the Tethys Ocean. In the past decades the Black Sea has been the subject of intense geological and geophysical studies. Several papers were published about the geological history, tectonics, basement relief and crustal and upper mantle structure of the basin. New tectonic schemes were suggested (e. g. Nikishin et al 2014, Shillington et al. 2008, Starostenko et al. 2004 etc.). Nevertheless, seismicity of the Black Sea is poorly studied due to the lack of seismic network in the coastal area. It is considered, that the eastern basin currently lies in a compressional setting associated with the uplift of the Caucasus and structural development of the Caucasus was closely related to the evolution of the Eastern Black Sea Basin. Analyses of recent sequence of earthquakes in 2012 can provide useful information to understand complex tectonic structure of the Eastern Black Sea region. Right after the earthquake of 2012/12/23, National Seismic monitoring center of Georgia deployed additional 4 stations in the coastal area of the country, close to the epicenter area, to monitor aftershock sequence. Seismic activity in the epicentral area is continuing until now. We have relocated approximately 1200 aftershocks to delineate fault scarf using data from Georgian, Turkish and Russian datacenters. Waveforms of the major events and the aftershocks were inverted for the fault plane solutions of the events. For the inversion were used green's functions, computed using new 1D velocity model of the region. Strike-slip mechanism of the major events of the earthquake sequence indicates extensional

  16. Indian Ocean dipole modulated wave climate of eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Anoop, T.R.; SanilKumar, V.; Shanas, P.R.; Glejin, J.; Amrutha, M.M.

    climate of the eastern Arabian Sea (AS). Using measured, modeled and reanalysis wave data and reanalysis wind data, we show that the IOD plays a major role in the variability of wave climate of the study region. Due to the IOD-induced changes in equatorial...

  17. Hydrography of the eastern Arabian Sea during summer monsoon ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 114; Issue 5. Hydrography of the eastern Arabian Sea during summer monsoon 2002. D Shankar S S C Shenoi R K Nayak P N Vinayachandran G Nampoothiri A M Almeida G S Michael M R Ramesh Kumar D Sundar O P Sreejith. Volume 114 Issue 5 October 2005 ...

  18. Characterising the sea ice environment using a newly developed sensor array mounted on an under-ice trawl

    OpenAIRE

    Lange, Benjamin; David, Car; Katlein, Christian; Meiners, Klaus M.; Nicolaus, Marcel; Peeken, Ilka; Flores, Hauke

    2014-01-01

    One of the most pronounced impacts of climate change is the changing sea ice cover, which has implications for sea ice-associated ecosystems that depend on carbon produced by ice-associated algae. In order to fully understand these ecosystems there is a need to understand both the physical and biological components. We present preliminary results from Polarstern cruises to the Eastern Central Arctic Ocean (summer 2012) and Weddell Sea (fall-winter 2013). Biological samples were acquired from ...

  19. Satellite observations of circulation in the Eastern Bering Sea

    Science.gov (United States)

    Paluszkiewicz, Theresa; Niebauer, H. J.

    1984-01-01

    Satellite infrared observations of the eastern Bering Sea shelf and basin were analyzed from December 1979 to August 1981. A region of warm surface water which extends from the Gulf of Alaska through the Aleutian Passes into the Bering Sea was observed coincident with a band of warm surface water and with eddies along the shelf break. The spatial and temporal relationships of these patterns imply a surface inflow through Unimak and other western Aleutian Passes, flow along the shelf break including eddies along the Bering Slope Current, and cyclonic flow in the basin. The proposed generating mechanisms for eddies along the shelf break include topographic interactions, baroclinic instabilities, and Rossby waves.

  20. Antarctic Sea Ice Patterns and Its Relationship with Climate

    Science.gov (United States)

    Barreira, S.

    2015-12-01

    Antarctic sea ice concentration fields show a strong seasonal and interannual variation closely tied to changes in climate patterns. The Ross, Amundsen, Bellingshausen, and Weddell Seas during Summer-Autumn and the Southern Ocean regions north of these areas during Winter-Spring have the greatest sea ice variability. Principal components analysis in T- mode, Varimax-rotated applied on Antarctic monthly sea ice concentration anomaly (SICA) fields for 1979-2015 (NASA Team algorithm data sets available at nsidc.org) revealed the main spatial characteristics of Antarctic sea ice patterns and their relationship with atmospheric circulation. This analysis yielded five patterns of sea ice for winter-spring and three patterns for summer-autumn, each of which has a positive and negative phase. To understand the links between the SICA patterns and climate, we extracted the mean pressure and temperature fields for the months with high loadings (positive or negative) of the sea ice patterns. The first pattern of winter-spring sea ice concentration is a dipole structure between the Drake Passage and northern regions of the Bellingshausen and Weddell Seas and, the South Atlantic Ocean. The negative phase shows a strong negative SICA over the Atlantic basin. This pattern can be associated with to the atmospheric structures related to a positive SAM index and a wave-3 arrangement around the continent. That is, a strong negative pressure anomaly centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. For summer-autumn, the first pattern shows two strong positive SICA areas, in the eastern Weddell Sea and the northwestern Ross Sea. A negative SICA covers the Amundsen-Bellingshausen Seas and northwest of the Antarctic Peninsula. This pattern, frequently seen in summers since 2008, is associated with cool conditions over the Weddell Sea but warmer temperatures and high surface air pressure west, north and northwest of the Peninsula.

  1. Associations between flatfish abundance and surficial sediments in the eastern Bering Sea

    National Research Council Canada - National Science Library

    Robert A. McConnaughey; Keith R. Smith

    2000-01-01

    Spatially explicit relationships between pleuronectid flatfish abundance and surficial sediments in the eastern Bering Sea were investigated using published sediment descriptions and trawl survey data (1982-1994...

  2. Penetration of coastal waters into the Eastern Mediterranean Sea using the SeaWiFS data

    OpenAIRE

    Karabashev, G; Evdoshenko, M; Sheberstov, S

    2002-01-01

    Offward transport of surface coastal waters was studied in the Eastern Mediterranean from 31degrees to 37degrees N between 31degrees to 36degrees E using cluster analysis of water-leaving radiance spectra from SeaWiFS color scanner imagery for spring-summer period of 1998. Some types of spectra were found to be characteristic of products of mixing of coastal and offshore waters and served as a quasiconservative tracer of water transport. Three sectors of the eastern coastal zone supplied colo...

  3. Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea

    NARCIS (Netherlands)

    Wolstencroft, M.; King, M.A.; Whitehouse, P.L.; Bentley, M.J.; Nield, G.A.; King, E.C.; McMillan, M.; Shepherd, A.; Barletta, V.; Bordoni, A.; Riva, R.E.M.; Didova, O.; Gunter, B.C.

    2015-01-01

    The measurement of ongoing ice-mass loss and associated melt water contribution to sea-level change from regions such as West Antarctica is dependent on a combination of remote sensing methods. A key method, the measurement of changes in Earth's gravity via the GRACE satellite mission, requires a

  4. Distribution of phosphorus in the eastern Adriatic Sea sediments (Croatia)

    Science.gov (United States)

    Matijević, Slavica; Bogner, Danijela; Kušpilić, Grozdan; Veža, Jere

    2014-05-01

    Phosphorus (P) is very important nutrient for the eastern Adriatic Sea owing to its limiting role in the primary production. Orthophosphate concentrations are low (median HPO42- value: 0.039 µmol dm-3) as a consequence of relatively small number of freshwater inflows and cyclonic circulation of oligotrophic eastern Mediterranean water masses. Due to anthropogenic influence in coastal areas such as bays, estuaries and channel waters, P concentrations increment occurred leading to the formation of trophic gradient from the open sea towards the coast. As marine sediment presents the ultimate sink for particulate organic P from the water column, as well as for inorganic P forms, knowledge about distribution of different sediment P species is of great importance for understanding the burial, diagenesis and environmental geochemical significance of P. This paper presents results of P distribution at the eastern Adriatic sites of different trophic status (open sea, channel, estuary, semi-enclosed bay under the anthropogenic influence and fish farms) during 2002-2012. In the water column dissolved and particulate inorganic and organic P were analyzed. In all sediments total phosphorus (organic and inorganic P) was determined, while at certain sites beside organic P, inorganic P forms were examined using modified SEDEX methods (P in biogenic - P-FD; authigenic - P-AUT and in detrital apatite - P-DET; phosphorus bound to iron oxides and hydroxides - P-Fe). Various geochemical variables in the water column and sediment (HPO42- concentration, sediment redox potential, granulometric composition, carbonate content, iron, organic carbon and total nitrogen content) were also investigated. Results proved total P concentrations range between 3 and 161 µmol g-1, with highest values at sites under the strong anthropogenic impact including fish farms, estuaries and bay areas. Major inorganic P species in the eastern Adriatic was P-Fe form. Fish debris P species P-FD, prevailed in

  5. Investigation of sea level trends and the effect of the north atlantic oscillation (NAO) on the black sea and the eastern mediterranean sea

    Science.gov (United States)

    Ozgenc Aksoy, Aysegul

    2017-07-01

    The North Atlantic Oscillation (NAO) has significant effects on sea levels, weather, and climate. In this study, the sea level trends and the effects of the North Atlantic Oscillation Indices (NAOI) on annual mean sea level data were assessed for the Black Sea and the Eastern Mediterranean Sea. The trends of sea level and NAOI were determined using Mann-Kendall dimensionless z statistics. Generally, upward sea level trends were detected for the Black Sea and the Eastern Mediterranean Sea. In the Black Sea, significant and continuous upward trends were detected after the year 1950. Weaker trends were detected for the Eastern part of the Mediterranean Sea. Sea level trends were correlated with trends in NAO indices; negative correlations were detected for the Black Sea, whereas positive correlations were found for the Eastern Mediterranean Sea. Paired t tests were performed to determine the turning points for all sea level data sets. The value of t was positive for all data sets, which means that the mean value of the data set before the turning point was smaller than the mean value of the data set after the turning point.

  6. Particle fluxes and organic carbon balance across the Eastern Alboran Sea (SW Mediterranean Sea)

    Science.gov (United States)

    Sanchez-Vidal, A.; Calafat, A.; Canals, M.; Frigola, J.; Fabres, J.

    2005-03-01

    As part of the "Mediterranean Targeted Project II—MAss Transfer and Ecosystem Response" (MTPII-MATER) EU-funded research project, particle flux data was obtained from three instrumented arrays moored along the 1°30' W meridian in the Eastern Alboran Sea. The mooring lines were deployed over 11 months, from July 1997 to May 1998, and were equipped with sediment trap-current metre pairs at 500-700, 1000-1200 and 2000-2200 m of water depth. The settling material was analysed to obtain total mass, lithogenic, calcium carbonate, organic carbon and opal fluxes. Integrated analysis of sediment trap and current meter data with sea-surface satellite images reveals that particle flux distribution is a function of primary production, mid-water lateral advection and near bottom nepheloid input. The spreading to the east and to the south of phytoplankton-rich water from the upwelling off the Spanish coast is controlled by the position and size of the Western and Eastern Alboran gyres, and drives the seasonal arrival of biogenic material down to the sea floor. Discrete lateral advection events unrelated to vertical entries of material can also supply particulate matter at 1000-1200 and 2000-2200 m of water depth as noted at the northern and southern stations. To achieve a better understanding of the carbon cycle in the area we have attempted to constrain the production, transfer and burial of particulate organic carbon, providing the first estimates of particulate organic carbon export in the Alboran Sea. Results suggest that sea surface circulation and associated productivity signal control the efficiency of the biological pump in the area. The export production in the Eastern Alboran Sea is higher than in other Mediterranean sites, with 0.5-0.9% of the carbon fixed during photosynthesis transferred down the water column and buried in the deep sediments. In addition, a large portion is supplied by lateral advection and through a benthic nepheloid layer, which represent a

  7. Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea

    DEFF Research Database (Denmark)

    Wolstencroft, Martin; King, Matt A.; Whitehouse, Pippa L

    2015-01-01

    The measurement of ongoing ice-mass loss and associated melt water contribution to sea-level change from regions such as West Antarctica is dependent on a combination of remote sensing methods. A key method, the measurement of changes in Earth's gravity via the GRACE satellite mission, requires...... a potentially large correction to account for the isostatic response of the solid Earth to ice-load changes since the Last Glacial Maximum. In this study, we combine glacial isostatic adjustment modelling with a new GPS dataset of solid Earth deformation for the southern Antarctic Peninsula to test the current...... understanding of ice history in this region. A sufficiently complete history of past ice-load change is required for glacial isostatic adjustment models to accurately predict the spatial variation of ongoing solid Earth deformation, once the independently-constrained effects of present-day ice mass loss have...

  8. Interannual and long-term sea level variability in the eastern Indian Ocean and South China Sea

    Science.gov (United States)

    Mohan, Soumya; Vethamony, P.

    2017-07-01

    Sea level anomalies (SLAs) derived from satellite observations (over a period of 22 years) and tide gauge data compiled from 66 stations from the eastern Indian Ocean and South China Sea (SCS) and western Pacific Ocean have been analyzed to study the interannual to long term variation of SLAs in the eastern Indian Ocean and SCS. Spatial patterns of sea level variability on the eastern boundary of the Indian Ocean exhibit non-coherent variability with SCS but show coherent variability with western Pacific Ocean. We find coherent variability in interannual SLAs in the Bay of Bengal, Andaman Sea, Malacca Strait and Java Strait. A large fraction of interannual SLA variations in the eastern SCS and interior SCS is linked to El Niño-Southern Oscillation (ENSO) and rest of the region is characterized by small scale interannual variations. The interannual SLAs in the SCS show seasonality with pronounced variation during winter and fall seasons. Interannual surface wind anomalies associated with Indian Ocean Dipole (IOD) and ENSO explain sea level interannual variability in the eastern Indian Ocean and SCS. The decadal sea level variability associated with Pacific Decadal Oscillation (PDO) and decadal ENSO are observed in the SCS.

  9. AFSC/RACE/EcoFOCI: 2010 Eastern Bering Sea Juvenile Survey - 1MF10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data collected on this cruise included the following: We conducted a juvenile fish and benthic fish prey survery in the eastern Bering Sea (61 3-meter beam trawls,...

  10. Obsolete - AFSC/RACE/Eco-FOCI: 2010 Eastern Bering Sea Juvenile Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data collected on this cruise included the following: We conducted a juvenile fish and benthic fish prey survery in the eastern Bering Sea (61 3-meter beam trawls,...

  11. Vertical distribution of mesozooplankton in the central and eastern Arabian Sea during the winter monsoons

    Digital Repository Service at National Institute of Oceanography (India)

    Padmavati, G.; Haridas, P.; Nair, K.K.C.; Gopalakrishnan, T.C.; Shiney, P.; Madhupratap, M.

    The vertical distribution of mesozooplankton in the central and eastern Arabian Sea was investigated during the winter monsoon in 1995. Samples were analysed from discrete depth zones defined according to oxygen and temperature profiles of the water...

  12. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  13. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (Oceanography data)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  14. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (TSG-thermosalinigraph data)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  15. Magnetic studies over the northern extension of the Prathap ridge complex, eastern Arabian sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Murty, G.P.S.; Srinivas, K.; Rao, D.G.

    The northern parts of the Prathap and Laccadive Ridge system, eastern Arabian Sea, consist of three parallel basement ridge peaks at varied depths. The topographic highs are associated with either well developed or subdued magnetic signatures. Model...

  16. Seasonal variability in oxygen and nutrients in the central and eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    De; DileepKumar, M.; Sardessai, S.; Sarma, V.V.S.S.; Shirodkar, P.V.

    Extensive observations made in the central and eastern Arabian Sea under JGOFS (India) programme suggest strong seasonal variations in concentrations of oxygen and nutrients in the water column. In the intermediate waters (depth range 150-800 m...

  17. AFSC/ABL: Eastern Bering Sea (EMA-BASIS) Zooplankton data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  18. Skate Bathyraja spp. egg predation in the eastern Bering Sea.

    Science.gov (United States)

    Hoff, G R

    2009-01-01

    Predation on skate eggs by snails was examined for three skate species at seven nursery sites in three regions (north, middle and south) of the eastern Bering Sea. Mean predation levels were 6.46% for the Alaska skate Bathyraja parmifera, 2.65% for the Aleutian skate Bathyraja aleutica and 22.25% for the Bering skate Bathyraja interrupta. Predation levels were significantly higher at the middle and north sites than the south sites for all species combined. Predation levels decreased with increasing egg-case densities at all nursery sites, and the highest predation levels occurred where egg-case densities were very low. Predated egg-case density increased with increasing snail densities across all nursery sites examined. The Oregon triton Fusitriton oregonensis was the most abundant snail species at all nursery sites and displayed ability to drill holes in the egg case of B. parmifera. Holes left by predatory snails in egg cases of B. parmifera were significantly larger, and of different shape at the middle site compared to the south site. Holes in B. parmifera were also significantly larger than those in egg cases of B. interrupta across all sites examined. Egg cases of B. aleutica possess surface spines that cover the egg case and may inhibit predation by snails at a greater rate than that of the B. parmifera and B. interrupta, which have a smoother egg-case surface.

  19. Corals, Canyons, and Conservation: Science Based Fisheries Management Decisions in the Eastern Bering Sea

    Directory of Open Access Journals (Sweden)

    Steve A. MacLean

    2017-05-01

    Full Text Available When making science matter for conservation, marine conservation practitioners, and managers must be prepared to make the appropriate decision based on the results of the best available science used to inform it. For nearly a decade, many stakeholders encouraged the North Pacific Fishery Management Council to enact protections for deep-sea corals in several canyons in the Eastern Bering Sea slope. In 2014, at the request of the Council, the National Marine Fisheries Service, Alaska Fisheries Science Center conducted a strip-transect survey along the Eastern Bering Sea slope to validate the results of a model predicting the occurrence of deep-sea coral habitat. More than 250,000 photos were analyzed to estimate coral, sponge, and sea whip abundance, distribution, height, and vulnerability to anthropogenic damage. The results of the survey confirmed that coral habitat and occurrence was concentrated around Pribilof Canyon and the adjacent slope. The results also confirmed that the densities of corals in the Eastern Bering Sea were low, even where they occurred. After reviewing the best available scientific information, the Council concluded that there is no scientific evidence to suggest that deep-sea corals in the Eastern Bering Sea slope or canyons are at risk from commercial fisheries under the current management structure, and that special protections for deep-sea corals were not warranted.

  20. Preliminary results of an acoustic tomography experiment (ATE-93) in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Somayajulu, Y.K.; Murty, T.V.R.; Navelkar, G.S.; Saran, A.K.; Almeida, A.M.; Murty, C.S.

    An acoustic transmission experiment was conducted in the eastern Arabian Sea by deploying two transceiver systems on deep sea moorings separatEd. by 270 km. The experiment lasted for a duration of ten days (2-12 May 1993). The acoustic transmissions...

  1. Abyssal and deep circulation in the Eastern Mediterranean Sea (Ionian Sea)

    Science.gov (United States)

    Artale, Vincenzo; Bensi, Manuel; Falcini, Federico; Marullo, Salvatore; Rubino, Angelo

    2016-04-01

    In the mid-1990s, experimental evidences on the Eastern Mediterranean Transient (EMT) were presented and it was shown that the Mediterranean abyssal circulation is not in a steady state but can be subjected to episodic sudden changes (Roether et al., 1996). In the last 10 years the Ionian Sea, the central and deepest part of the Mediterranean Sea, was subjected to relevant scientific interests from a theoretical and experimental point of view. Among these, there is the discovery of the BiOS (Bimodal Oscillating System), one new mechanism that drives a periodic (almost decadal) redistribution of surface and subsurface waters in the Eastern Mediterranean, with considerable feedbacks in the variability of the deep-water formation both in the southern Adriatic and in the Levantine and Aegean sub-basins (Gačić et al., 2010). In the Ionian Sea, numerous recent observational campaigns have been conducted to investigate the behaviour of deep and abyssal waters, at depths between 2000-4000m that are comparable to the mean global ocean depth (Rubino and Hainbucher, 2007; Bensi et al., 2013). There, advection, diffusion and vertical stability of the water masses can assume an important role on the internal quasi-periodical variability, creating the preconditions for catastrophic events such as the EMT or reversals of the Ionian circulation (Pisacane et al., 2006). Since there are no significant deep heat sources in the world ocean, waters that fill the deep ocean can only return to the sea surface as a result of downward mixing of heat from the sea surface to the bottom and vice versa and this occurs through eddy diffusion. Along our presentation, mainly through the analysis of the deepest CTD casts taken from 2009 to 2011 in the eastern basins and in particular in the Ionian Sea, we will show a significant change in the deep thermohaline structure (including its biogeochemical and hydrological characteristics), giving an indication on the time scale of the renewal of deep

  2. Polonium-210 and lead-210 in the Southern Polar Ocean: Naturally occurring tracers of biological and hydrographical processes in the surface waters of the Antarctic Circumpolar Current and the Weddell Sea; Polonium-210 und Blei-210 im Suedpolarmeer: Natuerliche Tracer fuer biologische und hydrographische Prozesse im Oberflaechenwasser des Antarktischen Zirkumpolarstroms und des Weddellmeeres

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, J.

    1997-11-01

    In this thesis the distribution of {sup 210}Po and {sup 210}Pb in the upper 600 m of the Antarctic Circumpolar Current and the Weddell Sea was investigated along north-south transects in austral spring and autumn. {sup 210}Po and {sup 210}Pb can serve as sensitive tracers for the special hydrographic conditions of the Antarctic Circumpolar Current and the Weddell Sea as well as for biological processes during phytoplankton blooms. The {sup 210}Po/{sup 210}Pb disequilibrium was used as a tracer for particle export. This tracer integrates export on a timescale of 276 days because of the 138 day half-life of {sup 210}Po and complements the {sup 234}Th/{sup 238}U disequilibrium as another tracer for plankton production and export on a shorter timescale of several weeks. (orig.) [Deutsch] In der vorliegenden Arbeit wurde die Verteilung von Blei-210 und seinem Enkelnuklid Polonium-210 im Antarktischen Zirkumpolarstrom und im Weddellmeer bis 600 m Tiefe in mehreren meridionalen Transekten im australen Fruehjahr und Herbst waehrend der `Polarstern`-Expeditionen ANT-X/6 und ANT-XI/4 untersucht. Die Verteilung von {sup 210}Pb und {sup 210}Po wird von mehreren Faktoren beeinflusst, sowohl durch die Advektion von Wassermassen im Antarktischen Zirkumpolarstrom und im Weddellmeer als auch von biologischen Prozessen z.B. innerhalb einer Planktonbluete. Bevor die Verteilungsmuster von {sup 210}Pb und {sup 210}Po jedoch als Tracer fuer einen Prozess genutzt werden koennen, muss der Effekt der einzelnen Faktoren auf die Verteilung betrachtet werden. (orig.)

  3. New gastropod records for the Eastern Mediterranean Sea and one new alien (Emarginula decorata Deshayes, 1863) for the Mediterranean Sea from NW Aegean Sea, Greece.

    Science.gov (United States)

    Manousis, Thanasis; Galinou-Mitsoudi, Sofia

    2014-12-01

    The NW Aegean Sea has a complex topography, high quality waters, oligotrophic to eutrophic conditions, is connected with estuaries and wetlands, is of high ecological interest, harbours all the types of human activities and yet few researchers work on its marine biodiversity. With this study, the contribution to the knowledge of the Hellenic and Eastern Mediterranean gastropod biodiversity of the studied families is continued, and an expansion of the search in other substrates and deeper waters of the NW Aegean Sea with emphasis on the minor in size species during the period from October 2008 to January 2014. Thirty seven species belonging to seven families (Cerithiopsidae, Fissurellidae, Phasianellidae, Scissurellidae, Siliquariidae, Skeneidae, and Triphoridae) were identified and their biodiversity was compared with the current checklists of marine gastropod molluscs for the Hellenic Seas based on previous surveys. In this collection of gastropods, one species (Emarginula decorata Deshayes, 1863) is a new alien for the Mediterranean Sea, 14 species are new for the Eastern Mediterranean Sea and 16 species are new for the Hellenic fauna (with the one above mentioned alien species included). The main identification characteristics and ecological information such as habitat, distribution, alien expansion paths to the NW Aegean Sea and origin of the species are given and discussed. The Hellenic gastropod biodiversity of the studied families was enriched with 37 new records for the N Aegean Sea, out of which 16 are new for Greece, 14 are new for the Eastern Mediterranean Sea while one (Emarginula decorata) is a new alien for the Mediterranean Sea.

  4. The Response of the Aegean Sea (Eastern Mediterranean) to the Extreme 2016-2017 Winter

    Science.gov (United States)

    Velaoras, Dimitris; Papadopoulos, Vassilis P.; Kontoyiannis, Harilaos; Papageorgiou, Dimitra K.; Pavlidou, Alexandra

    2017-09-01

    The exceptionally cold December 2016 over the Aegean Sea—one of the most important dense water formation areas of the eastern Mediterranean Sea—resulted in winter heat loss comparable to the peak Eastern Mediterranean Transient winters (1992-1993). Hydrological data sampled in March/April 2017 showed that newly produced dense waters ventilated the North Aegean deep basins up to density horizons of σθ 29.35 kg/m3. The water column ventilation was unable to reach the bottom as the present upper thermohaline circulation of the eastern Mediterranean does not favor the salinity preconditioning of the Aegean Sea. In the southwest Aegean, the Myrtoan basin was ventilated by dense waters traceable farther south to the West Cretan Straits. Export of these masses from the Aegean Sea can potentially have a broader impact on the thermohaline circulation of the eastern Mediterranean.

  5. Ongoing decline of shark populations in the Eastern Red Sea

    KAUST Repository

    Spät, Julia L.Y.

    2016-06-30

    Information on the abundance and diversity of Red Sea elasmobranchs is notoriously scarce, even though sharks are among the most profitable fisheries of the region. Effective conservation would ideally entail baselines on pristine conditions, yet no such data is available for the Red Sea. To collect distribution and abundance data on Red Sea elasmobranchs, we conducted a dedicated longline and Baited Remote Underwater Video system (BRUVs) sampling program along the entire Red Sea coast of Saudi Arabia over the course of two years. Both survey techniques were opportunistically employed at central and southern Saudi Arabian (SA) Red Sea reef systems. In addition, BRUVs were employed in the northern SA Red Sea and at selected reef systems in Sudan. Shark catch per unit effort (CPUE) data for BRUVs and longline surveys were compared to published data from non-Red Sea reef systems. This comparison revealed CPUE estimates several orders of magnitude lower for both survey methods in the SA Red Sea compared to other reef systems around the world. Catch per unit effort values of BRUVs on Sudanese reefs on the contrary were within the range of estimates from various locations where sharks are considered common. We argue that decades of heavy fishing pressure on Red Sea marine resources has significantly altered the community structure of SA Red Sea reefs. There is an urgent need to establish effective management strategies for species of highest conservation concern. Our results have the potential to be used as a baseline, if such management strategies were to be established. © 2016 Elsevier Ltd

  6. SEA SURFACE TEMPERATURES RECONSTRUCTION OF THE LAST 16,000 YEARS IN THE EASTERN MEDITERRANEAN SEA

    Directory of Open Access Journals (Sweden)

    SIMONA GIUNTA

    2001-11-01

    Full Text Available A detailed study has been performed on two eastern Mediterranean box cores (BC02 and BC06 and on a southern Adriatic piston core (AD91-17 on the alkenone unsaturation ratio, a molecular proxy for past sea surface temperatures. The aim was to identify climatic events of the last 16 Ky, with particular attention on the conditions during formation of sapropel S1. All three temperature curves lack evidence for cooling in the Younger Dryas stadial and warming in the Boelling/Alleroed interstadial events. Just prior to the sapropel S1 base, SST cooled and increased by about 5°C during the sapropel deposition interval. Within sapropel S1, SST show a marked warming followed by a clear cooling. In the topmost intervals of the cores SST are mostly constant, but a warming event is always observed. This warming phase may correspond to the Medieval climatic Optimum (in the AD91-17 core and to the Roman Optimum (in the box cores.

  7. Iron-rich Basal sediments from the eastern equatorial pacific: leg 16, deep sea drilling project.

    Science.gov (United States)

    Cronan, D S; Van Andel, T H; Heath, G R; Dinkelman, M G; Bennett, R H; Bukry, D; Charleston, S; Kaneps, A; Rodolfo, K S; Yeats, R S

    1972-01-07

    Iron-rich sediments chemically similar to those forming at present on the crest of the East Pacific Rise have been found just above basement at widely separated drill sites in the eastern equatorial Pacific, including three sites of Leg 16 of the Deep Sea Drilling Project. These sediments were probably formed when the basement was at the crest of this rise and have moved to their present location as a result of sea-floor spreading.

  8. Institutional barriers to organic farming in Central and Eastern European countries of the Baltic Sea region

    OpenAIRE

    Larsson, Markus; Morin, Louise; Hahn, Thomas; Sandahl, Johanna

    2013-01-01

    A window of opportunity to promote organic farming is open for the Central andEastern European Countries (CEEC) that joined the EU in 2004. The development oforganic farming has the potential to decrease the amount of nutrient leaching tothe Baltic Sea and could help to stop the environmental degradation of the Sea.However, this requires a diverse set of institutions. This paper explores theinstitutions that are lacking to promote the full development of organic farming inthe CEEC, using Swed...

  9. Interannual variability of chlrophyll concentration in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Karanje, S.

    the instrument itself, the SeaWiFS Project has developed and operates a research data system that processes, calibrates, validates, archives and distributes data received from an Earth-orbiting ocean color sensor. Chlorophyll With the SeaWiFS instrument... scientific instrument on GeoEye's OrbView-2 (AKA SeaStar) satellite, and was a follow-on experiment to the Coastal Zone Color Scanner on Nimbus 7. Launched August 1, 1997 on an Orbital Sciences Pegasus small air launched rocket, the instrument began...

  10. Deep Sea Pockmark Environments in the eastern Mediterranean

    NARCIS (Netherlands)

    Dimitrov, L.; Woodside, J.M.

    2003-01-01

    A great number of circular to isometric depressions have been observed on the deep water seafloor in the eastern Mediterranean by MAK-1 and ORETech deep-tow side-scan sonar during several TTR cruises of the UNESCO Floating University Program since 1993, and also by visual observations made during

  11. Seasonal controls on surface pCO 2 in the central and eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; Gauns, M.; Madhupratap, M.

    The variability in partial pressure of carbon dioxide (pCO 2) and its control by biological and physical processes in the mixed layer (ML) of the central and eastern Arabian Sea during inter-monsoon, northeast monsoon, and southwest monsoon seasons...

  12. Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Menon, H.B.; Sangekar, N.; Lotliker, A.; Moorthy, K.K.; Vethamony, P.

    Data from the ocean-colour monitor (OCM) on board the Indian Remote Sensing Satellite P4 were used to analyse the spatial and temporal distribution of aerosol optical thickness (AOT) over the coastal and offshore waters of the eastern Arabian Sea...

  13. Spatial and temporal variation of surface waves in shallow waters along the eastern Arabian Sea.

    Digital Repository Service at National Institute of Oceanography (India)

    Anoop, T.R.; SanilKumar, V.; Shanas, P.R.

    We studied the spatial and temporal variation of surface waves along the eastern Arabian Sea during 2011 and 2012. Measured directional wave data at two shallow water locations and re-analysis datasets (ERA-Interim) at 0.751 intervals at four...

  14. STUDY ON THE OSCILLATION RELATIONSHIP BETWEEN SEA ICE OF THE ARCTIC AND ANTARCTIC

    OpenAIRE

    / /; Simei, XIE; Chenglan, BAO; Chunjiang, HAO

    1994-01-01

    In this paper, the Antarctic sea ice is divided into four regions : SPI1 (0°-120°E), the eastern Antarctic region; SPI2 (120°E-120°W), centered at the Ross Sea; SPI3 (120°W-0°), centered at the Weddell Sea. SPI4,the whole Antarctic sea region. The Arctic sea ice is divided into three regions : NPI1 (90°E-180°-90°W) on the Pacific-side; NPI2 (90°W-0°-90°E) on the Atlantic-side. NPI3,the whole Arctic sea region. In this paper, by mathematical statistical methods, the SIGRID polar sea ice data p...

  15. Modes of sedimentary basin formation in the north-eastern Black Sea

    Science.gov (United States)

    Stephenson, Randell; Starostenko, Vitaly; Sydorenko, Grygoriy; Yegorova, Tamara

    2016-04-01

    The Greater Caucasus and Black Sea sedimentary basins developed in a Mesozoic back-arc setting, the former older than the latter (Jurassic v. Cretaceous). Compressional shortening of the former and accompanying ongoing development of marginal basin depocentres in the north-eastern Black Sea - which is closely tied to the formation of the Crimea-Greater Caucasus orogen - is a Cenozoic phenomenon, starting in the Eocene and proceeding until the present day. Recently, the sedimentary basin/crust/lithosphere geometry of the study area has been characterised across a range of scales using regional seismic reflection profiling, long-offset refraction/wide-angle reflection profiling and local earthquake tomography. These provide a new integrated image of the present-day crustal structure and sedimentary basin architecture of the northern margin of the eastern Black Sea, north across the Azov Sea and provide evidence of the deeper expression of sedimentary basins and the processes controlling the geometry of their inversion during the Cenozoic. It is inferred that the Greater Caucasus paleo-Basin, lying stratigraphically below the Black Sea and younger sedimentary successions, extends further to the west than previously known. This basin has significant thickness in the area between the Azov and Black seas and probably forms the deeper core of the Crimea-Caucasus inversion zone. The Crimea-Greater Caucasus orogenic belt is the expression of "basin inversion" of the Jurassic Greater Caucasus paleo-Basin, the degree of inversion of which varies along strike. The Greater Caucasus foredeep basins - Indolo-Kuban and Sorokin-Tuapse troughs -represent syn-inversional marginal troughs to the main inversion zone. The Shatsky Ridge - the northern flank of the main East Black Sea Basin - may also be mainly a syn-inversional structure, underlain by a blind thrust zone expressed as a northward dipping zone of seismicity on the northern margin of the eastern Black Sea.

  16. Biometric properties and diet of common pandora, Pagellus erythrinus (Osteichthyes: Sparidae, from the eastern Adriatic sea

    Directory of Open Access Journals (Sweden)

    Šantić M.

    2011-01-01

    Full Text Available Biometric properties and diet composition were examined in 120 specimens of the common pandora caught in the eastern Adriatic Sea. Biometric analysis of the morphometric and meristic characteristics indicate a homogenous morphology stock of P. erythrinus in the eastern Adriatic Sea. Changes in some of the morphometric characteristics obtained in conjunction with an increase in body length showed that smaller specimens have a longer dorsal fin, standard length, eye diameter and postorbital distances than larger specimens. The meristic characteristics of the common pandora from Italian waters and the Black Sea are mostly in agreement with data in our study. The prey species identified in the stomachs belong to five groups: Decapoda, Bivalvia, Polychaeta, Teleostei and Euphausiacea. Decapods were the most important ingested prey group while bivalves were second in importance. Various prey groups and species found in the stomach indicate that the common pandora could be an opportunistic predator.

  17. Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1500 to 1800 A.D.

    Directory of Open Access Journals (Sweden)

    J. ANTONOPOULOS

    1980-06-01

    Full Text Available Tsunamis from 1500-1800 A.D., in the Eastern Mediterranean
    Sea between 31-44 N and 18-36 E excluding the Black Sea and the
    Italian coasts of the Adriatic Sea is the object of the present
    paper.

  18. Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1800 to 1900 A.D.

    Directory of Open Access Journals (Sweden)

    J. ANTONOPOULOS

    1980-06-01

    Full Text Available Tsunamis from 1800-1900 A.D. in the Eastern Mediterranean
    Sea between 31-44 N and 18-36 E excluding the Black Sea and
    the Italian coasts of the Adriatic Sea is the object of the present
    paper.

  19. Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1000 to 1500 A.D.

    Directory of Open Access Journals (Sweden)

    J. ANTONOPOULOS

    1980-06-01

    Full Text Available Tsunamis from 1000 to 1500 A.D. in the Eastern Mediterranean
    Sea between 31-44 N and 18-36 E excluding the Black Sea
    and the Italian coasts of the Adriatic Sea is the object of the
    present paper.

  20. Data from investigation on seismic Sea waves events in the Eastern Mediterranean from 1900 to 1980 A.D.

    Directory of Open Access Journals (Sweden)

    J. ANTONOPOULOS

    1980-06-01

    Full Text Available Tsunamis from 1900 to 1980 A.D. in the Eastern Mediterranean
    Sea between 31-44 N and 18-36 E excluding the Black Sea
    and the Italian coasts of the Adriatic Sea is the object of the
    present paper.

  1. ORGANOCHLORINE CONTAMINANTS IN SEA TURTLES FROM THE EASTERN PACIFIC

    Science.gov (United States)

    We measured organochlorine residues in three species of sea turtles from the Baja California peninsula, Mexico. Seventeen of 21 organochlorine pesticides analyzed were detected, with heptachlor epoxide and y-hexachlorocyclohexane the most prevalent in 14 (40%) and 11 (31%) of th...

  2. Distribution of aerobic anoxygenic phototrophs in the Eastern Adriatic Sea

    Czech Academy of Sciences Publication Activity Database

    Šantić, D.; Šestanović, S.; Vrdoljak, A.; Šolić, M.; Kušpilić, G.; Ninčević Gladan, Ž.; Koblížek, Michal

    2017-01-01

    Roč. 130, SEP 2017 (2017), s. 134-141 ISSN 0141-1136 R&D Projects: GA MŠk(CZ) LO1416 Institutional support: RVO:61388971 Keywords : Aerobic anoxygenic phototrophs * Adriatic sea * Picoplankton Subject RIV: EE - Microbiology, Virology Impact factor: 3.101, year: 2016

  3. Growth Rate Potential of Juvenile Sockeye Salmon in Warmer and Cooler Years on the Eastern Bering Sea Shelf

    Directory of Open Access Journals (Sweden)

    Edward V. Farley

    2009-01-01

    Full Text Available A spatially explicit bioenergetics model was used to predict juvenile sockeye salmon Oncorhynchus nerka growth rate potential (GRP on the eastern Bering Sea shelf during years with cooler and warmer spring sea surface temperatures (SSTs. Annual averages of juvenile sockeye salmon GRP were generally lower among years with cooler SSTs and generally higher in offshore than nearshore regions of the eastern Bering Sea shelf during years with warmer SSTs. Juvenile sockeye salmon distribution was significantly (P<.05 related to GRP and their prey densities were positively related to spring SST (P<.05. Juvenile sockeye salmon GRP was more sensitive to changes in prey density and observed SSTs during years when spring SSTs were warmer (2002, 2003, and 2005. Our results suggest that the pelagic productivity on the eastern Bering Sea shelf was higher during years with warmer spring SSTs and highlight the importance of bottom-up control on the eastern Bering Sea ecosystem.

  4. Southern Ocean Climate and Sea Ice Anomalies Associated with the Southern Oscillation

    Science.gov (United States)

    Kwok, R.; Comiso, J. C.

    2001-01-01

    The anomalies in the climate and sea ice cover of the Southern Ocean and their relationships with the Southern Oscillation (SO) are investigated using a 17-year of data set from 1982 through 1998. We correlate the polar climate anomalies with the Southern Oscillation index (SOI) and examine the composites of these anomalies under the positive (SOI > 0), neutral (0 > SOI > -1), and negative (SOI oscillating climate anomalies that are closely linked to the SO. Within these sectors, positive (negative) phases of the SOI are generally associated with lower (higher) sea-level pressure, cooler (warmer) surface air temperature, and cooler (warmer) sea surface temperature in these sectors. Associations between these climate anomalies and the behavior of the Antarctic sea ice cover are clearly evident. Recent anomalies in the sea ice cover that are apparently associated with the SOI include: the record decrease in the sea ice extent in the Bellingshausen Sea from mid- 1988 through early 199 1; the relationship between Ross Sea SST and ENSO signal, and reduced sea ice concentration in the Ross Sea; and, the shortening of the ice season in the eastern Ross Sea, Amundsen Sea, far western Weddell Sea, and the lengthening of the ice season in the western Ross Sea, Bellingshausen Sea and central Weddell Sea gyre over the period 1988-1994. Four ENSO episodes over the last 17 years contributed to a negative mean in the SOI (-0.5). In each of these episodes, significant retreats in the Bellingshausen/Amundsen Sea were observed providing direct confirmation of the impact of SO on the Antarctic sea ice cover.

  5. Distribution of drifting seaweeds in eastern East China Sea

    Science.gov (United States)

    Komatsu, Teruhisa; Tatsukawa, Kenichi; Filippi, Jean B.; Sagawa, Tatsuyuki; Matsunaga, Daisuke; Mikami, Atsuko; Ishida, Kenichi; Ajisaka, Tetsuro; Tanaka, Katsuhiko; Aoki, Masakazu; Wang, Wei-Ding; Liu, Hui-Fei; Zhang, Shou-Du; Zhou, Min-Dong; Sugimoto, Takashige

    2007-09-01

    In offshore waters with relatively low primary production, drifting seaweeds composed of Sargassum species form an identical ecosystem such as an oasis in desert. Commercially important pelagic fishes such as jack mackerel ( Trachurus japonicus) and yellow tail ( Seriola quinqueradiata) spawn in East China Sea pass their juvenile period accompanying drifting seaweeds. Therefore drifting seaweeds are very important not only in offshore ecosystem but also fishery resources. However the distribution of drifting seaweeds in East China Sea has scarcely known. Then we conducted two research cruises of R/V Hakuho-Maru in May 2002 and in March 2004. During the cruises, drifting seaweeds were visually observed from the bridge and sampled with a towing net. The observation revealed that the drifting seaweeds were distributed along the front between the Kuroshio Current and coastal waters and mainly composed of one seaweed species, Sargassum horneri (Turner) C. Agardh from spring to early summer. There are no reports on geographical distribution of this species in the coasts south of southern Kyushu Island in Japan. Kuroshio Current flows northeastward there. Buoys with GPS attached to drifting seaweeds released off Zhejiang Province, China, in March 2005 to track their transport. Their positions monitored by ORBCOM satellite showed that they were transported to the area in East China Sea, where the drifting seaweeds were observed during the cruises, in 2 months. These facts suggest that S. horneri detached from Chinese coast in March or months earlier than March could be transported to fringe area of continental shelf and waters influenced by Kuroshio Current from March to May. Therefore the Sargassum forests, especially S. horneri, along the Chinese coast play a very important role in the ecosystem of the East China Sea as a source of drifting seaweeds.

  6. Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Rachael [Faculty of Veterinary Science, University of Sydney, NSW 2006 Australia (Australia); Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia)], E-mail: rgray@vetsci.usyd.edu.au; Canfield, Paul [Faculty of Veterinary Science, University of Sydney, NSW 2006 (Australia); Rogers, Tracey [Australian Marine Mammal Research Centre PO Box 20 Mosman, NSW 2088 (Australia); Evolution and Ecology Research Centre and School of Biological Earth and Environmental Sciences, University of New South Wales, NSW 2052 (Australia)

    2008-07-25

    Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.

  7. Trace element analysis in the serum and hair of Antarctic leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii.

    Science.gov (United States)

    Gray, Rachael; Canfield, Paul; Rogers, Tracey

    2008-07-25

    Leopard seal, Hydrurga leptonyx, and Weddell seal, Leptonychotes weddellii, occupy an upper trophic level within the Antarctic ecosystem and are useful indicator species in the Southern Ocean of trace element concentrations. Reference values for the concentration of 19 trace elements were determined in the serum and hair of leopard and Weddell seals sampled in Eastern Antarctica. These reference values can be used as 'baseline' levels for monitoring trace element concentrations in these species. Greater trace element concentrations were determined in hair compared to serum, indicating different time scales of trace element accumulation in these samples. For the majority of trace elements, except for Se in the leopard seal samples and Cr in the Weddell seal samples, significant regression relationships for trace element concentrations in hair and serum were not elucidated. Significant differences were determined in the concentrations of seven out of 15 elements with hair type, moult and new, in the leopard seal; concentrations in moult hair were determined to be greater than in new hair for all elements except Zn. Hair analysis was determined to be useful for monitoring exposure to trace elements and when collected off the ice from moulting seals, hair can be employed as a non-invasive sample for trace element analysis in leopard and Weddell seals.

  8. Hydrography of the eastern Arabian Sea during summer monsoon 2002

    Digital Repository Service at National Institute of Oceanography (India)

    Shankar, D.; Shenoi, S.S.C.; Nayak, R.K.; Vinayachandran, P.N.; Nampoothiri, G.S.; Almeida, A.M.; Michael, G.S.; RameshKumar, M.R.; Sundar, D.; Sreejith, O.P.

    of the ASHSW, PGW, and RSW decreased equatorward, and that of the RSW also decreased offshore. The observations suggest that the RSW is advected equatorward along the continental slope off the Indian west coast. 1. Introduction In this paper, we describe... (Bruce et al 1994; Shankar and Shetye 1997; Han and McCreary 2001). Below 200 m too, salinity increased poleward and the high-salinity patch at 500 m (which corresponds to 27 sigmat) north of 15openbulletN is a clear sign of Red Sea Water (RSW...

  9. Shallow water wave spectral characteristics along the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Shanas, P.R.; Dubhashi, K.K.

    pools’’ in the tropics where the probability of swell was more than 95%. The highest wave conditions occur in the Southern Ocean with average Hm0 more than 4 m (Hanley et al. 2010). Wolf et al. (2011) found that waves in Liverpool Bay were mainly... for wind-sea (Wolf et al. 2011). Significant steepness [=2π Hm0/(g Tm02 Tm02)] varied from 1:18 to 1:283 with higher steepness values (mean steepness 1:48) at Ratnagiri and lower values (mean steepness 1:65) at Honnavar. The higher steepness values...

  10. Eastern Exit: Rescue"...From the Sea"

    Science.gov (United States)

    2008-01-01

    Department at the Naval War College. He earned a PhD in history at Texas Christian University in Fort Worth and holds three master’s degrees. He attended the...leaders.25 Amphibious Squadron 6 (PHIBRON 6), commanded by Captain Alan B. Moser , had been among the first naval forces to sail to the Arabian Sea...roughly the size of a small Marine expeditionary force but without a MEF headquarters to structure and direct it.30 Therefore, when LaPlante and Moser

  11. Diverse and highly recombinant anelloviruses associated with Weddell seals in Antarctica

    Science.gov (United States)

    Fahsbender, Elizabeth; Kim, Stacy; Kraberger, Simona; Frankfurter, Greg; Eilers, Alice A.; Shero, Michelle R.; Beltran, Roxanne; Kirkham, Amy; McCorkell, Robert; Berngartt, Rachel K.; Male, Maketalena F.; Ballard, Grant; Ainley, David G.; Breitbart, Mya

    2017-01-01

    Abstract The viruses circulating among Antarctic wildlife remain largely unknown. In an effort to identify viruses associated with Weddell seals (Leptonychotes weddellii) inhabiting the Ross Sea, vaginal and nasal swabs, and faecal samples were collected between November 2014 and February 2015. In addition, a Weddell seal kidney and South Polar skua (Stercorarius maccormicki) faeces were opportunistically sampled. Using high throughput sequencing, we identified and recovered 152 anellovirus genomes that share 63–70% genome-wide identities with other pinniped anelloviruses. Genome-wide pairwise comparisons coupled with phylogenetic analysis revealed two novel anellovirus species, tentatively named torque teno Leptonychotes weddellii virus (TTLwV) -1 and -2. TTLwV-1 (n = 133, genomes encompassing 40 genotypes) is highly recombinant, whereas TTLwV-2 (n = 19, genomes encompassing three genotypes) is relatively less recombinant. This study documents ubiquitous TTLwVs among Weddell seals in Antarctica with frequent co-infection by multiple genotypes, however, the role these anelloviruses play in seal health remains unknown. PMID:28744371

  12. Relative sea-level variability during the late Middle Pleistocene: New evidence from eastern England

    Science.gov (United States)

    Barlow, N. L. M.; Long, A. J.; Gehrels, W. R.; Saher, M. H.; Scaife, R. G.; Davies, H. J.; Penkman, K. E. H.; Bridgland, D. R.; Sparkes, A.; Smart, C. W.; Taylor, S.

    2017-10-01

    Unravelling patterns of relative sea-level change during previous interglacials enhances our understanding of ice sheet response to changing climate. Temperate-latitude estuarine environments have the potential to preserve continuous records of relative sea level from previous interglacial (warm) periods. This is important because, currently, we typically only have snapshots of sea-level highstands from low-latitude corals and raised palaeoshoreline indicators while the (continuous) deep-sea oxygen isotope record only provides indirect evidence of sea-level changes. Here, we focus on the Nar Valley in eastern England, in which is preserved evidence of a late middle-Pleistocene marine transgression more than 20 vertical metres in extent. By applying a model of coastal succession and sea-level tendencies, as used in Holocene sea-level studies, we assess the mode (abrupt versus gradual) of sea-level change recorded by the interglacial Nar Valley sequences. Compiled palaeo-stratigraphic evidence comprising foraminifera, pollen and amino acid racemization dating, suggests that the mode of sea-level change in the Nar Valley interglacial sequence was gradual, with potentially two phases of regional transgression and relative sea-level rise occurring at two separate times. The first phase occurred during the latter part of marine Oxygen Isotope Stage (MIS) 11 from ∼8 to 18 m OD; and, the second phase potentially occurred during early MIS 9 from ∼-3 to 3 m OD (with long-term tectonic uplift included in these estimates). We cannot conclusively preclude an alternative MIS 11 age for these lower sediments. The lack of indicators for rapid sea-level oscillations in the Nar Valley adds weight to an argument for steady melt of the ice sheets during both MIS 11 and 9.

  13. Characteristic features of the dynamics of carbonate parameters in the eastern part of the Laptev Sea

    Science.gov (United States)

    Pipko, I. I.; Pugach, S. P.; Semiletov, I. P.

    2015-02-01

    This report presents the results of studies of the sea water carbonate system performed in September 2011 at the inner, middle, and outer shelf of the east of the Laptev Sea. It was shown that the key factor controlling the carbonate chemistry of the shelf waters during the warm season is the significant terrigenous runoff. In the autumn season, the surface waters of the inner and middle shelf of the eastern part of the Laptev Sea are a source of carbon dioxide to the atmosphere; those of the outer shelf act as a sink of atmospheric CO2. It is found that the waters of the inner shelf of the east of the Laptev Sea over the entire water column are now corrosive against calcium carbonate. The surface and near-bottom waters of the middle shelf are also undersaturated with respect to aragonite. It was shown that the main factors determining the undersaturation are the significant volume of freshwaters supplied with the riverine runoff and the ice melting, as well as the large amount of labile allochthonous organic matter involved into the modern biogeochemical cycle at the shelf. The performed studies showed that the shelf waters of the eastern part of the Laptev Sea constitute one of the most corrosive zones with respect to calcium carbonate in the World Ocean.

  14. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

  15. Sedimentary Environments of the Sea Floor off Eastern Cape Cod, Massachusetts (CC_ENVIRON.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes the sedimentary environments for the sea floor offshore of northern and eastern Cape Cod, Massachusetts. This interpretation is based on data...

  16. AFSC/NMML: Cetacean line-transect survey in the eastern Bering Sea shelf; 1999, 2000, 2002, and 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC.s echo integration trawl surveys for...

  17. Temperature, salinity, and dissolved oxygen profile data from MULTIPLE SHIPS in the Eastern Mediterranean Sea: (NODC Accession 9400176)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Conductivity, Temperature and Depth (CTD) and other data were collected in Mediterranean Sea, Eastern Basin as part of Mediterranean Ocean Circulation project. Data...

  18. Acoustic-Trawl Survey of Walleye Pollock on the Eastern Bering Sea Shelf (DY1407, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey on the eastern Bering Sea...

  19. Variation of paleo-productivity and terrigenous input in the eastern Arabian Sea during the past 100 ka

    Digital Repository Service at National Institute of Oceanography (India)

    Ishfaq, A.M.; Pattan, J.N.; Matta, V.M.; Banakar, V.K.

    A 4.1m long sediment core from the eastern Arabian Sea is studied using multiple geochemical proxies to understand the variation of productivity and terrigenous matter supply during the past 100 ka. The temporal variation in element concentration...

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

    DEFF Research Database (Denmark)

    Dybkjær, Karen; Piasecki, Stefan

    2010-01-01

    . Absolute ages of the new dinocyst zones are proposed based on correlation from the studied succession within the North Sea Basin with the international zonations and stratigraphic schemes. In addition, parts of the succession have been dated by strontium isotope analysis of mollusc shells. Inconsistencies...... due to first and last occurrences of some dinocyst species in previous studies and the present study, especially within the Lower Miocene, implied that new Sr-isotope datings from mollusc shells from the cored Sdr. Vium borehole and other localities in this study would be invaluable. Indeed......, this method allowed the previous last occurrence of Cordosphaeridium cantharellus (one of the zonal index fossils) dated as between 17.95 My and 19.5 My in previous studies, to be assigned a new dating of 18.4 My. The timespan of the zones range from 2.6 My for the Amiculospharea umbraculum Zone to 0.4 My...

  1. Census of biodiversity in marine caves of the eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    V. GEROVASILEIOU

    2015-03-01

    Full Text Available Scientific information on the biodiversity of marine caves in the eastern Mediterranean is limited, especially when considering the extensively studied caves of the north-western and central Mediterranean. Aiming to enhance current knowledge regarding cave communities, this study represents a first assessment of the marine cave biota of the eastern Mediterranean, as this has been defined by the European Union’s Marine Strategy Framework Directive (MSFD. Information retrieved from an extensive overview of relevant scientific documents was combined with original data recorded from 23 marine caves of the north-eastern Mediterranean. Our results report a total of 520 taxa recorded in eastern Mediterranean marine caves to date, the majority of which are sponges, polychaetes, rhodophytes, bivalves, fishes, and gastropods. These include several protected, endemic, and alien species. However, not all taxonomic groups have been equally studied among different areas and future studies are expected to raise the number of endemic and alien species. The overall observed trend is that the reported species number is generally related to sampling effort and scientific expertise. The most well-studied marine cave communities of the eastern Mediterranean are those of the Aegean Sea (especially its northern sector, which presented the highest number of species, followed by those of the Levantine. Furthermore, our research in Aegean caves revealed numerous new records for the marine cave fauna of the eastern basin, while several species are reported for the first time in the marine cave habitat. The critical need for further scientific research, monitoring, and conservation of this unique ecosystem was highlighted by (i the presence of certain species endemic to the eastern Mediterranean coupled with a high proportion of alien species, especially in the Levantine, and (ii the marine cave habitat availability in isolated insular areas of the eastern Mediterranean.

  2. A teleconnection between Atlantic sea surface temperature and eastern and central North Pacific tropical cyclones

    Science.gov (United States)

    Patricola, Christina M.; Saravanan, R.; Chang, Ping

    2017-01-01

    The El Niño-Southern Oscillation (ENSO) is a major source of seasonal tropical cyclone (TC) predictability in both local and remote ocean basins. Unusually warm eastern-central equatorial Pacific sea surface temperature (SST) during El Niño tends to enhance eastern and central North Pacific (ECNP) TCs and suppress Atlantic TCs. Here we demonstrate that Atlantic SST variability likewise influences remote TC activity in the eastern-central Pacific through a Walker Circulation-type response analogous to the ENSO-Atlantic TC teleconnection, using observations and 27 km resolution tropical channel model (TCM) simulations. Observed and simulated ECNP TC activity is reduced during the positive Atlantic Meridional Mode (AMM), which is characterized by warm northern and cool southern tropical Atlantic SST anomalies, and vice versa during the negative AMM. Large ensembles of TCM simulations indicate that SST variability, rather than internal atmospheric variability, drives extreme ECNP hurricane seasons.

  3. Biogeochemistry of lead in the eastern Arabian Sea and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; DineshKumar, P.K.; Bahulayan, N.

    SCROLL DOWN FOR ARTICLE This article was downloaded by: [CSIR eJournals Consortium] On: 1 October 2010 Access details: Access Details: [subscription number 919661628] Publisher Taylor & Francis Informa Ltd Registered in England and Wales Registered Number... large-scale hydrological 223 Downloaded By: [CSIR eJournals Consortium] At: 04:58 1 October 2010 224 G. Rejomon et al. Figure 1. Map of the eastern Arabian Sea with station locations. imbalances and appear to be regions of intense scavenging by suspended...

  4. Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae) in Eastern Arabian Sea

    OpenAIRE

    Geetha Sasikumar; K.S. Mohamed; U.S. Bhat

    2013-01-01

    Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C), distributed along the Eastern Arabian Sea (South-West coast of India). For this, the Dorsal Mantle Length (...

  5. A Probabilistic Model of Illegal Drug Trafficking Operations in the Eastern Pacific and Caribbean Sea

    Science.gov (United States)

    2013-09-01

    Illicit drug - trafficking is a major concern of the United States and is a primary pillar of President Barack Obama’s Strategy to Combat Transnational...Organized Crime. In the eastern Pacific and Caribbean Sea, drug - trafficking organizations operate a variety of vessels to transit drugs from South...interdicts illegal drug - trafficking in this region. In this thesis, we develop a probability model based on intelligence inputs to generate a spatial

  6. Estimation and Monitoring of Wind/Wave energy potential in the Eastern Mediterranean Sea

    Science.gov (United States)

    Zodiatis, George; Galanis, George; Galanis, George; Emmanouil, George; Emmanouil, George; Hayes, Dan; Nikolaidis, Andreas; Georgiou, Georgios; Kalogeri, Christina; Kallos, George

    2013-04-01

    Τhe adaptation and use of innovative methodologies for the exploitation of renewable energy marine resources is one of the main issues today for the environmental science community. Within this framework, the exploitation of wind and wave energy potential for coastal and island states seems to be one of the promising solutions and highly interesting from research and technological point of view. In this work, the activities of two projects focusing on the study of wind/wave energy over the area of Eastern Mediterranean Sea are presented. The "Integrated High Resolution System for Monitoring and Quantifying the Wave Energy Potential in the EEZ of Cyprus" (Ewave project) focuses on the estimation, monitoring and forecasting of the wave energy potential over the Levantine Basin with special emphasis to the Exclusive Economical Zone of Cyprus, while the "Development and application of new mathematical and physical models for Monitoring the wind and Sea wave Energy Potential" (MOSEP project) is a platform for developing new mathematical algorithms for the estimation of the wave energy over the Aegean Sea. In both projects, high resolution digital atlases of sea wave/wind climatological characteristics and the distribution of the wind and wave energy potential are developed for the coastal and offshore areas of the East Mediterranean sea . Moreover, new models for the prediction and quantification of wave energy in short and long forecast horizons are proposed. Statistical results concerning the probability density functions of the wind speed, the significant wave height, as well as the energy potential will be presented for selected sea areas in the Eastern Mediterranean Sea, while test case studies in certain regions favor to wind/wave renewable energy will be discussed.

  7. New gastropod records for the Eastern Mediterranean Sea and one new alien (Emarginula decorata Deshayes, 1863) for the Mediterranean Sea from NW Aegean Sea, Greece

    OpenAIRE

    Manousis, Thanasis; Galinou-Mitsoudi, Sofia

    2014-01-01

    Background The NW Aegean Sea has a complex topography, high quality waters, oligotrophic to eutrophic conditions, is connected with estuaries and wetlands, is of high ecological interest, harbours all the types of human activities and yet few researchers work on its marine biodiversity. With this study, the contribution to the knowledge of the Hellenic and Eastern Mediterranean gastropod biodiversity of the studied families is continued, and an expansion of the search in other substrates and ...

  8. Radionuclides and trace metals in eastern Mediterranean Sea algae

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masri, M.S. E-mail: msmasri@aec.org.sy; Mamish, S.; Budier, Y

    2003-07-01

    Three types of sea alga distributed along the Syrian coast have been collected and analyzed for radioactivity and trace elements. Results have shown that {sup 137}Cs concentrations in all the analyzed sample were relatively low (less than 1.2 Bq kg{sup -1} dry weight) while the levels of naturally occurring radionuclides, such as {sup 210}Po and {sup 210}Pb, were found to be high in most samples; the highest observed value (27.43 Bq kg{sup -1} dry weight) for {sup 210}Po being in the red Jania longifurca alga. In addition, most brown alga species were also found to accumulate {sup 210}Po, which indicates their selectivity to this isotope. On the other hand, brown alga (Cystoseira and Sargassum Vulgare) have shown a clear selectivity for some trace metals such as Cr, As, Cu and Co, this selectivity may encourage their use as biomonitor for pollution by trace metals. Moreover, the red alga species were found to contain the highest levels of Mg while the brown alga species were found to concentrate Fe, Mn, Na and K and nonmetals such as Cl, I and Br.

  9. Dissolved aluminium in the Weddell-Scotia Confluence and effect of Al on the dissolution kinetics of biogenic silica

    Energy Technology Data Exchange (ETDEWEB)

    Bennekom, A.J. van; Buma, A.G.J.; Nolting, R.F. (Netherlands Inst. for Sea Research, Den Burg (Netherlands))

    1991-11-01

    In the Scotia and Weddell Seas the concentration of dissolved Al was 1-1.5 nM in ice-free surface waters, up to 3 nM in ice-covered waters and about 2.6 nM in bottom waters. The solubility and the dissolution rate of diatomaceous silica, obtained from net samples and from incubations in the presence or absence of dissolved Al, were inversely related to solid-phase Al/Si ratios. At in situ temperatures, dissolution rates from Antarctic diatoms are higher than those for diatoms from temperature regions. Effects on distribution patterns of silicic acid in the Weddell Sea are discussed. (author). 32 refs.; 3 figs.; 2 tabs.

  10. Spatio-temporal development of sinkholes on the eastern shore of the Dead Sea

    Science.gov (United States)

    Holohan, Eoghan; Saberi, Leila; Al-Halbouni, Djamil; Sawarieh, Ali; Closson, Damien; Alrshdan, Hussam; Walter, Thomas; Dahm, Torsten

    2017-04-01

    The ongoing, largely anthropogenically-forced decline of the Dead Sea is associated with the most prolific development of sinkholes worldwide. The fall in hydrological base level since the 1960s is thought to enable relatively fresh ground waters to dissolve underground salt deposits that were previously in equilibrium with hypersaline Dead Sea brine. Sinkhole development in response to this dissolution began in the 1980s and is still ongoing; it represents a significant geohazard in the Dead Sea region. We present new research undertaken within the Dead Sea Research Venue (DESERVE) on the spatio-temporal evolution of the main sinkhole-affected site on the Eastern shore of the Dead Sea, at Ghor Al-Haditha in Jordan. Our data set includes optical satellite imagery, aerial survey photographs and drone-based photogrammetric surveys with high spatial (sinkhole sites. Our analysis shows that there are now over 800 sinkholes at Ghor al-Haditha. Sinkholes initiated as spatially distinct clusters in the late 1980's to early 1990s. While some clusters have since become inactive, most have expanded and merged with time. New clusters have also developed, mainly in the more recently exposed north of the area. With the retreat of the Dead Sea, the roughly coastline-parallel zone of sinkhole formation has expanded unevenly but systematically seawards. Such a seaward migration of sinkhole formation is predicted from hydrogeological theory, but as yet not consistently observed elsewhere at the Dead Sea. The rate of sinkhole formation at Ghor Haditha accelerated markedly during the late 2000s to a peak of about 100 per year in 2009. Similar accelerations are observed on the western shore, but differ in timing. The rate of sinkhole formation on the Eastern shore has since declined to about 50 per year. Such differences in the overall spatio-temporal evolution of sinkholes on the eastern and western shores of the Dead Sea likely highlights the important role of local hydrogeological

  11. Revisiting the Last Glacial-Interglacial Productivity Paradox in the Eastern Arabian Sea

    Science.gov (United States)

    Naik, D. K.; Saraswat, R.; Nigam, R.; Lea, D. W.; Kurtarkar, S. R.; Singh, D. P.; Mackensen, A.

    2014-12-01

    The Southern Ocean enhanced iron fertilization induced primary productivity can account only for ~40 ppm out of the total 80-100 ppm change in atmospheric CO2 during the last glacial-interglacial transition. Additional mechanism or regions with increased glacial productivity have to be identified to account for the remaining 40-60 ppm change in atmospheric CO2. The Arabian Sea is one of the most productive tropical regions at present. Even though a majority of the past productivity records from the Arabian Sea suggest reduced primary production during the glacial period, contrasting results have been obtained from the eastern Arabian Sea, suggesting a possible role of this region in controlling glacial-interglacial atmospheric CO2 changes. Here we reconstruct paleo-productivity changes from the eastern Arabian Sea during the past ~32 kyr, from foraminiferal and geochemical studies on a gravity core (SK 237 GC04). We infer that the productivity in the southeastern Arabian Sea was high during the MIS3 with well oxygenated waters. An abrupt decrease in productivity is inferred during early deglaciation and it coincides with Heinrich event (HS-1), suggesting a close relationship between monsoon in the eastern Arabian Sea and the climatic change in North Atlantic. A synchronous productivity collapse in the SEAS during global depleted δ13C event, suggests that the productivity collapse was partially responsible for the depleted δ13C during HS-1. The high glacial productivity as noted in Malabar core as well as a few other cores collected from similar water depths is not noticed in all the cores collected from the southeastern Arabian Sea. It suggests that though the productivity was higher in this region during glacial times but the overall resultant carbon sequestration was confined only to a restricted zone and might not be large enough to substantially alter atmospheric CO2. The productivity was also high during the early Holocene monsoon optimum. A close

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

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    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.

  13. A possible adaptation of herring feeding migrations to a change in timing of the Calanus finmarchicus season in the eastern North Sea

    NARCIS (Netherlands)

    Corten, A.

    2000-01-01

    During the first years after the re-opening of the North Sea herring fishery in 1983, a relatively high proportion of the catches in early summer was taken in the eastern North Sea. After 1986, the proportion of the catch in the eastern North Sea gradually declined. It is assumed that the high

  14. Geothermal structure of the eastern Black Sea basin and the eastern Pontides orogenic belt: Implications for subduction polarity of Tethys oceanic lithosphere

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    Nafiz Maden

    2013-07-01

    Full Text Available The numerical results of thermal modeling studies indicate that the lithosphere is cold and strong beneath the Black Sea basin. The thermal lithospheric thickness increases southward from the eastern Pontides orogenic belt (49.4 km to Black Sea basin (152.2 km. The Moho temperature increases from 367 °C in the trench to 978 °C in the arc region. The heat flow values for the Moho surface change between 16.4 mW m−2 in the Black Sea basin and 56.9 mW m−2 in the eastern Pontides orogenic belt. Along the southern Black Sea coast, the trench region has a relatively low geothermal potential with respect to the arc and back-arc region. The numerical studies support the existence of southward subduction beneath the Pontides during the late Mesozoic–Cenozoic.

  15. Sulfate-reducing prokaryotic communities in two deep hypersaline anoxic basins in the Eastern Mediterranean deep sea

    NARCIS (Netherlands)

    van der Wielen, Paul W. J. J.; Heljs, Sander K.

    In the Eastern Mediterranean Sea, deep hypersaline anoxic basins (DHABs) and deep-sea sediment contain anoxic environments where sulfate reduction is an important microbial metabolic process. The objective of this study was to characterize the sulfate-reducing community in the brine and interface of

  16. Objective mapping of temperature field by stochastic inverse method using acoustic tomography experimental data of eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, T.V.R.; Rao, M.M.M.; Sadhuram, Y.

    An acoustic transmission experiment was conducted in the eastern Arabian Sea along 12.5 degrees N latitude for a duration of ten days (2-12 May, 1993), with two transceiver systems deployed on deep sea moorings, separated by a range of 270.92 km...

  17. Feeding grounds of the eastern South Pacific humpback whale population include the South Orkney Islands

    Directory of Open Access Journals (Sweden)

    Luciano Dalla Rosa

    2012-03-01

    Full Text Available This paper reports on two photo-identified humpback whales (Megaptera novaeangliae that were sighted in different years in the proximity of the South Orkney Islands, at the boundary between the Scotia and Weddell seas (60°54.5'S—46°40.4'W and 60°42.6'S—45°33'W. One of the whales had been previously sighted off Ecuador, a breeding ground for the eastern South Pacific population. The other whale was subsequently resighted in Bransfield Strait, off the western Antarctic Peninsula, a well-documented feeding ground for the same population. These matches give support to a hypothesis that the area south of the South Orkney Islands is occupied by whales from the eastern South Pacific breeding stock. Consequently, we propose 40°W as a new longitudinal boundary between the feeding grounds associated with the eastern South Pacific and western South Atlantic breeding stocks.

  18. The wind and thermally driven circulation of the eastern Mediterranean Sea. Part II: the Baroclinic case

    Science.gov (United States)

    Malanotte-Rizzoli, Paola; Bergamasco, Andrea

    1991-04-01

    anticyclonic ones in summer, according to the vorticity input by the wind. When surface thermal forcing is included, the winter-to-summer differences become very small and the yearly pattern is dominant. The second important result is that the intercomparisons of the various numerical experiments in which each driving mechanism is studied in isolation from the others allows us to classify unambiguously the three forcing mechanisms in order of relative importance in driving the circulation in the different sub-basins of the eastern Mediterranean. Specifically, for the Ionian Sea and Sea of Crete the dominant forcing is the inflow at the Straits of Sicily while for the Levantine Sea thermohaline fluxes are the main driving function. The wind-stress forcing induces a seasonal fluctuation only in the meandering path of the Atlantic jet entering the Ionian Sea through the Sicily Straits. We finally carry out a 'central experiment', the most realistic one in which all forcing functions drive the circulation that we compare quantitatively with other model results and qualitatively with observations. Major features can be recognized and are shown to be persistent all year long. These features are also found in the dynamic heights of the general hydrographic surveys of the Physical Oceanography of the Eastern Mediterranean (POEM) programme. The only POEM feature not reproduced by the model, an intense anticyclonic region in the south eastern Levantine, may be attributed to errors and specifically underestimates, of the available thermal fluxes whose effect is partially overcome by the wind-stress forcing. This anticyclonic cell is in fact obtained when the model is driven by the thermal fluxes alone. Overall, the model results compare well with the observational evidence provided by the POEM surveys and the thermohaline vertical circulation cell reproduced by the model is consistent with the preliminary results of the transient-tracer survey POEM-V-87. Finally, many of the persistent

  19. Multidisciplinary oil spill modeling to protect coastal communities and the environment of the Eastern Mediterranean Sea

    Science.gov (United States)

    Alves, Tiago M.; Kokinou, Eleni; Zodiatis, George; Radhakrishnan, Hari; Panagiotakis, Costas; Lardner, Robin

    2016-01-01

    We present new mathematical and geological models to assist civil protection authorities in the mitigation of potential oil spill accidents in the Eastern Mediterranean Sea. Oil spill simulations for 19 existing offshore wells were carried out based on novel and high resolution bathymetric, meteorological, oceanographic, and geomorphological data. The simulations show a trend for east and northeast movement of oil spills into the Levantine Basin, affecting the coastal areas of Israel, Lebanon and Syria. Oil slicks will reach the coast in 1 to 20 days, driven by the action of the winds, currents and waves. By applying a qualitative analysis, seabed morphology is for the first time related to the direction of the oil slick expansion, as it is able to alter the movement of sea currents. Specifically, the direction of the major axis of the oil spills, in most of the cases examined, is oriented according to the prevailing azimuth of bathymetric features. This work suggests that oil spills in the Eastern Mediterranean Sea should be mitigated in the very few hours after their onset, and before wind and currents disperse them. We explain that protocols should be prioritized between neighboring countries to mitigate any oil spills. PMID:27830742

  20. Early winter mesozooplankton of the coastal south-eastern Barents Sea

    Science.gov (United States)

    Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

    2015-01-01

    The south-eastern Barents Sea (Pechora Sea) is a little studied region of the Russian Arctic. We investigated mesozooplankton community of this area in early winter period for the first time. The study was based on collections performed with a Juday net (168 μm) in November 2010. Three types of stations differing in mesozooplankton composition and abundance were revealed by non-metric multidimensional scaling analyses. Taxa richness and diversity of the mesozooplankton were high. The total abundance and biomass varied from 931 to 4360 individuals m-3 and from 4.0 to 64.2 mg dry mass m-3, respectively. Maximum density of mesozooplankton was located in the hydrographical frontal zone where cold and warm waters interacted. Copepods dominated in terms of the total abundance. Abundances of major taxa were strongly correlated with environmental variables, of which temperature, salinity and depth were the most important. Previous studies showed that many mesozooplankton are in a dormant state during the Arctic winter from October to April. However, our investigation found young copepodites to be present for many of the common copepod species, which suggests successful reproduction of some opportunistic taxa (Pseudocalanus, Acartia, Temora, Oithona) and that the small copepod community was in an active phase. The main factor influencing possible development of the copepods in the south-eastern Barents Sea was river run-off which supplied plankton with detritus and suspended organic matter.

  1. Precipitation over eastern South America and the South Atlantic Sea surface temperature during neutral ENSO periods

    Science.gov (United States)

    Bombardi, Rodrigo J.; Carvalho, Leila M. V.; Jones, Charles; Reboita, Michelle S.

    2014-03-01

    The dominant mode of coupled variability over the South Atlantic Ocean is known as "South Atlantic Dipole" (SAD) and is characterized by a dipole in sea surface temperature (SST) anomalies with centers over the tropical and the extratropical South Atlantic. Previous studies have shown that variations in SST related to SAD modulate large-scale patterns of precipitation over the Atlantic Ocean. Here we show that variations in the South Atlantic SST are associated with changes in daily precipitation over eastern South America. Rain gauge precipitation, satellite derived sea surface temperature and reanalysis data are used to investigate the variability of the subtropical and tropical South Atlantic and impacts on precipitation. SAD phases are assessed by performing Singular value decomposition analysis of sea level pressure and SST anomalies. We show that during neutral El Niño Southern Oscillation events, SAD plays an important role in modulating cyclogenesis and the characteristics of the South Atlantic Convergence Zone. Positive SST anomalies over the extratropical South Atlantic (SAD negative phase) are related to increased cyclogenesis near southeast Brazil as well as the migration of extratropical cyclones further north. As a consequence, these systems organize convection and increase precipitation over eastern South America.

  2. Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

    Science.gov (United States)

    Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

    2017-01-01

    Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

  3. Zooplankton incidence in abnormally high sea surface temperature in the Eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    and internal waves may cause zooplankton abundance. Average biomass values in high sea surface temperature areas were higher (0.30 ml.m/3) than at the other stations (0.07 ml.m/3). Crustacean eggs, fish eggs and mysids clustered in pockets of abnormally high...

  4. Deep-sea ichthyofauna from Eastern Mediterranean Sea, Egypt: Update and new records

    Directory of Open Access Journals (Sweden)

    Mahmoud M.S. Farrag

    2016-12-01

    Full Text Available This work sheds light on deep sea resources that update the list of deep sea ichthyoids fauna with new records from the Egyptian coast, Mediterranean Sea. Fish samples were collected from April to November 2015 at depths of 350–750 m using deep red shrimp bottom trawlers. The presented fauna were constituted mainly of deep red shrimp (Aristeomorpha folicea and Aristeus antennatus as target species followed by by-catch and discards which were represented by 36 fish species; Of them, 21 species were recorded previously. The rest of the species, were new ichthyofauna identified in fifteen species including 4 cartilaginous species (Centrophorus uyato, Etmopterus spinax, Hydrolagus mirabilis and Chimaera monstrosa, while the other 11 species were bony fishes (Chauliodus sloani, Diaphus metopoclampus, Sudis hyaline, Microstoma microstoma, Chlorophthalmus agassizi, Avocettina infans, Argyropelecus hemigymnus, Notacanthus bonaparte, Lampanyctus crocodilus, Centrolophus niger and Nettastoma melanurum. Centrophorus uyato was reported for the first time in the Levant Basin. The present findings added new species to the Egyptian ichthyofauna and raised the total known deep water fauna to 38 species, enhancing knowledge about such species requires continuous monitoring and studies on deep sea resources.

  5. Trophic Status of the South-Eastern Baltic Sea: A Comparison of Coastal and Open Areas

    Science.gov (United States)

    Wasmund, N.; Andrushaitis, A.; Łysiak-Pastuszak, E.; Müller-Karulis, B.; Nausch, G.; Neumann, T.; Ojaveer, H.; Olenina, I.; Postel, L.; Witek, Z.

    2001-12-01

    Primary production, nutrient concentrations, phytoplankton biomass (incl. chlorophyll a) and water transparency (Secchi depth), are important indicators of eutrophication. Earlier basin-wide primary production estimates for the Baltic Sea, a shallow shelf sea, were based mainly on open-sea data, neglecting the fundamentally different conditions in the large river plumes, which might have substantially higher production. Mean values of the period 1993-1997 of nutrient concentrations (phosphate, nitrate, ammonium and silicate), phytoplankton biomass, chlorophyll a (chl a) concentration, turbidity and primary production were calculated in the plumes of the rivers Oder, Vistula and Daugava and Klaipeda Strait as well as the open waters of the Arkona Sea, Bornholm Sea, eastern Gotland Sea and the Gulf of Riga. In the plumes, these values, except for primary production, were significantly higher than in the open waters. N:P ratios in the plumes were >16 (with some exceptions in summer and autumn), indicating potential P-limitation of phytoplankton growth, whereas they were <16 in the open Baltic Proper, indicating potential N-limitation. On the basis of in situ phytoplankton primary production, phytoplankton biomass and nutrient concentrations, the large river plumes and the Gulf of Riga could be characterized as eutrophic and the outer parts of the coastal waters and the open sea as mesotrophic. Using salinity to define the border of the plumes, their mean extension was calculated by means of a circulation model. Taking into account the contribution of coastal waters, the primary production in the Baltic Proper and the Gulf of Riga was 42·6 and 4·3×10 6 t C yr -1, respectively. Hence, an annual phytoplankton primary production in the whole Baltic Sea was estimated at 62×10 6 t C yr -1. The separate consideration of the plumes had only a minor effect on the estimation of total primary production in comparison with an estimate based on open sea data only. There is

  6. High oxygen consumption rates in the deep layers of the North Aegean Sea (eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    E. SOUVERMEZOGLOU

    2002-06-01

    Full Text Available Severe winter meteorological conditions promote dense water formation over the shelves of the North Aegean Sea. The newly formed dense water fills the deep basins of the North Aegean Sea, contributing to their ventilation and the downward transport of organic and inorganic material. The great bathymetric variability imposes limitations on the deep circulation and the communication between the various basins and makes the North Aegean Sea an appropriate area for the monitoring of oxygen consumption in the deep layers. Historical hydrographic data suggest that there was extensive production of dense water in the North Aegean Sea on two occasions during the last decade, the winters of 1987 and 1992-1993. Our data series from August 1986 to September 1989 and from March 1997 to February 1999, permitted us to follow, step by step, the oxygen consumption and the nutrient regeneration in the deep basins of the northern Aegean Sea during these periods of isolation. The organic matter reaching the bottom layer just after the deep water formation event is rich in labile and easily oxidizable material and its decomposition leads to a significant oxygen uptake during the first year of stagnation. The further decomposition of the remaining semi-labile and refractory material turns over on greater time scales, by consuming lesser amounts of oxygen. A more significant oxygen decrease is recorded in the eastern basin (Lemnos Basin of the North Aegean Trough, than in the central (Athos Basin and the western (North Sporades Basin ones and is attributed to the irregular contribution of the Black Sea Water (BSW to the water masses formed on the different shelves of the North Aegean Sea. Our results and the existing data on the Turkish straits showed that dissolved organic matter is the major constituent responsible for this high oxygen consumption. The slightly different particulate organic carbon fluxes to these depressions play a secondary role.

  7. Wind-forced depth-dependent currents over the eastern Beaufort Sea continental slope

    Science.gov (United States)

    Dmitrenko, Igor; Kirillov, Sergei; Forest, Alexandre; Tremblay, Bruno; Lukovich, Jennifer; Gratton, Yves; Rysgaard, Soren; Barber, David

    2017-04-01

    The shelfbreak current over the Beaufort Sea continental slope is known to be one of the most energetic features of the Beaufort Sea hydrography. This current transports a fraction of the Pacific-derived water along the Beaufort Sea continental slope towards Fram Strait. The oceanographic mooring deployed over the Canadian (eastern) Beaufort Sea continental slope in October 2003 at 300 m depth recorded current velocity through 28-108 m depths over two consecutive years until September 2005. Data analysis revealed that the high energetic currents show two different modes of the depth-dependent behavior. The downwelling favourable local wind associated with cyclones passing north of the Beaufort Sea continental slope toward the Canadian Archipelago generates depth-intensified shelfbreak currents with along-slope northeastward flow up to 120 cm/s. A surface Ekman on-shore transport and associated increase of the sea surface heights over the shelf produce a cross-slope pressure gradient that drives an along-slope northeastward geostrophic flow, in the same direction as the wind. In contrast, the surface intensified currents with along-slope westward flow are observed in response to the upwelling favourable wind forcing associated with the Pacific-born cyclones passing south of the Beaufort Sea coast. The upwelling favourable northeasterly winds generate a surface Ekman transport that moves surface waters offshore. The associated cross-slope pressure gradient drives an along-slope southwestward barotropic flow. The wind-driven barotropic flow generated by downwelling- and upwelling-favourable wind forcing is superimposed on the background geostrophic bottom-intensified shelfbreak current. For the downwelling events, this amplifies the depth-intensified background baroclinic circulation with enhanced Pacific water transport towards Canadian Archipelago and Fram Strait. For the upwelling events, the shelfbreak current is reversed. This results in surface-intensified flow

  8. Geological evidence of tsunamis and earthquakes at the Eastern Hellenic Arc: correlation with historical seismicity in the eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Gerassimos Papadopoulos

    2012-12-01

    Full Text Available Sedimentary stratigraphy determined by trenching in Dalaman, south-western Turkey, revealed three sand layers at a distance of approximately 240 m from the shoreline and at elevations of +0.30, +0.55 and +0.90 cm. Storm surge action does not explain the features of these deposits that show instead typical characteristics of tsunami deposition. The sand layers correlate with historical tsunamis generated by large earthquakes which ruptured the eastern Hellenic Arc and Trench in 1303, 1481 and 1741. Accelerator mass spectrometry 14C dating of a wood sample from layer II indicated deposition in AD 1473±46, which fits the 1481 event. From an estimated average alluvium deposition rate of approximately 0.13 cm/year, layers I and III were dated at 1322 and 1724, which may represent the large 1303 and 1741 tsunamis. The geological record of the 1303 key event is very poor; therefore, sand layer I perhaps represents an important geological signature of the 1303 tsunami. However, the strong tsunami reported to have been generated by the 1609 earthquake is missing from Dalaman stratigraphy: this underlines the sensitivity of tsunami geological signatures to various local factors. The 1303 earthquake ruptured the trench between the islands of Crete and Rhodes. For the earthquakes of 1481, 1609 and 1741 we suggested that they were very likely generated in the Rhodes Abyssal Plain where sea depths of up to approximately 4200 m, together with the thrust component of seismotectonics, favor tsunami generation. Sand dykes directed upwards from layer I to layer II indicated that the 1481 earthquake triggered liquefaction of sand layer I. The results substantially widen our knowledge about the historical earthquake and tsunami activity in the eastern Mediterranean basin.

  9. Scenario of Methane and Gas Hydrate occurrences in different geological settings in the eastern Mediterranean Sea

    Science.gov (United States)

    Karisiddaiah, S. M.

    2003-04-01

    An attempt is made here to unravel the various types of methane occurrences in the eastern Mediterranean Sea. First part devotes on the occurrence of methane in anoxic brines, in sea water and in the underlying sediments, while the next half concentrates on the significance of methane in the natural gas hydrates with in the sediments under special P-T conditions from mud volcanoes of Anaximander Mountain Ranges and Mediterranean Ridges as reported by various researchers. Very high methane concentrations (128-2692 mM) occur in the hypersaline anoxic brine pools of Bannock and Urania, within the Eastern Mediterranean Sea, compared to its concentrations (17 to 80 m M) in the sediment cores below the anoxic brines. Besides, in the underlying sediments bit higher range in methane (10-158 nM) values occur, compared to low methane (1.47-7.14 nM) concentrations in the overlying water column and the basins surrounding Crete Island. The methane enrichment in the brines might be due to the long residence time of brine in the basin, and to its high stability toward mixing with overlying seawater. Possible sources for this methane enrichment could be a deep source of hydrothermal activities, prevalence of gas hydrate horizons and occurrence of sapropels. Gas hydrate research had reached an astounding position in the earth sciences. The present day situation of natural gases for the entire world caused an alarming strategy to search for new clean fuel energy, such as the one sequestered in the gas hydrates. In this context an attempt is made here to review the significance of gas hydrate occurrences in the eastern Mediterraneans mainly from Anaximander Mountain Range mud volcanoes (which are characterized by a concentric zonal distribution of gas hydrates) and mud volcanoes in Mediterranean Ridges which might be the future sites for gas hydrate exploration.

  10. Sea level changes along the Turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    B. ALPAR

    2000-06-01

    On the average, there is a pronounced sea-level difference (55 cm along the Turkish Straits System. However, the slope is nonlinear, being much steeper in the Strait of Istanbul. This barotrophic pressure difference is one of the most important factors causing the two-layer flow through the system. The topography and hydrodynamics of the straits, the dominant wind systems and their seasonal variations make this flow more complicated. For secular sea level changes, a rise of 3.2 mm/a was computed for Karsiyaka (1935-71 and a steady trend (-0.4 mm /a has been observed for annual sea levels at Antalya (1935-77. The decreasing trend (-6.9 mm/a at Samsun is contrary to the secular rising trend of the Black Sea probably because of its rather short monitoring period (1963-77.

  11. Distribution and abundance of pelagic shrimps from the deep scattering layer of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Karuppasamy, P.K.; Menon, N.G.; Nair, K.K.C.; Achuthankutty, C.T.

    cover their role in the productivity of the ocean. The importance of ing the of FORV sampada as part: of a DSL pelagic shrimps as sonic scatters, food for larger animals, and as program in ~~di~ EEZ between M~~ 1998 to ~~~~~b~~ 2000 in agents... shrimps, deep scattering layer, geographical distribution, vertical migration, swarming behavior INTRODUCTION was carried out for understanding their distribution pattern, abun- dance and die1 vertical migrations in the eastern Arabian Sea. Since...

  12. Amino Acid Composition of Blue Crab (Callinectes sapidus) from the North Eastern Mediterranean Sea

    OpenAIRE

    KÜÇÜKGÜLMEZ, Aygül; ÇELIK, Mehmet

    2008-01-01

    The amino acid composition in tissues (claw, breast meats and hepatopancreas) of the blue crabs (Callinectes sapidus, RATHBUN, 1896), caught off the North Eastern Mediterranean Sea (Turkey) were investigated. The amounts of the amino acid contents of the claw, breast meat and hepatopancreas of the blue crab were found to be significantly different. Glutamic acid was major amino acid in all parts of the blue crab. The total essential amino acids ranged from 7.24 to 7.83 g/ 100 g fresh wt. The ...

  13. Hydrodynamic and Thermohaline Seasonal Structures of Peninsular Malaysia's eastern continental shelf sea

    Science.gov (United States)

    Daryabor, Farshid; Tangang, Fredolin; Juneng, Liew

    2010-05-01

    The seasonal ocean circulation and the seasonal thermal structure in Peninsular Malaysia's eastern continental shelf sea were studied numerically using the Regional Ocean Model System (ROMS) with 18-km horizontal resolution and 50 sigma levels conforming to a realistic bottom topography. A 10-year control run was performed using climatological monthly mean wind stresses, restoring-type surface salt, temp and heat, and observational oceanic inflow/outflow at the open boundaries. The seasonally averaged effects of isolated forcing terms are presented and analyzed from the following experiments: 1) heat fluxes effects removed and 2) wind effects removed. This procedure allowed analysis of the contribution of individual parameters to the general hydrology and specific features of the Peninsular Malaysia's eastern continental shelf sea: for example, coastal jets, mesoscale topographic gyres, and countercurrents. The results show that the ROMS model has the capability of simulating seasonal variations of the Peninsular Malaysia's eastern continental shelf sea circulation and thermohaline structure. The simulated Peninsular Malaysia's eastern continental shelf sea surface circulation is generally anticyclonic (cyclonic) during the summer (winter) monsoon period with a strong western boundary current, a mean maximum speed of 0.8 m s-1 (0.5 m s-1), and extending to a depth of around 30 m (40 m). During summer, the western boundary current splits and partially leaves the coast; the bifurcation point is at 40°N in Jun and shifts north to 70°N in July. A mesoscale eddy on the Sunda shelf, the southwest of Natuna Island at (2.50°N, 1060°E) and extending to two mesoscale eddy at (20°N, 1070°E) and (2.50°N, 1090°E) also on the Gulf of Thailand (7.50°N, 1040°E), was also simulated. These eddies are cyclonic (anticyclonic) with maximum swirl velocity of 0.3 m s-1 at the peak of the summer (winter) monsoon. The simulated thermohaline structure for summer and winter are

  14. Modeling the barrier-layer formation in the South-Eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Durand, F.; Shankar, D.; DeBoyer Montegut, C.; Shenoi, S.S.C.; Blanke, B.; Madec, G.

    -layer formation in the South-Eastern Arabian Sea F. Durand1, D. Shankar2, C. de Boyer Mont?gut3, S.S.C. Shenoi2, B. Blanke4, G. Madec3 (1) IRD, LEGOS, UMR5566 CNRS-CNES-IRD-UPS, 14 Avenue Edouard Belin, 31400 Toulouse, France (2) Physical Oceanography Division..., National Institute of Oceanography, Dona Paula, Goa 403004, India (3) Laboratoire d?Oc?anographie et de Climatologie : Exp?rimentation et Analyses Num?riques, Universit? Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05, France (4) Laboratoire...

  15. Sedimentology and geochemistry of mud volcanoes in the Anaximander Mountain Region from the Eastern Mediterranean Sea.

    Science.gov (United States)

    Talas, Ezgi; Duman, Muhammet; Küçüksezgin, Filiz; Brennan, Michael L; Raineault, Nicole A

    2015-06-15

    Investigations carried out on surface sediments collected from the Anaximander mud volcanoes in the Eastern Mediterranean Sea to determine sedimentary and geochemical properties. The sediment grain size distribution and geochemical contents were determined by grain size analysis, organic carbon, carbonate contents and element analysis. The results of element contents were compared to background levels of Earth's crust. The factors that affect element distribution in sediments were calculated by the nine push core samples taken from the surface of mud volcanoes by the E/V Nautilus. The grain size of the samples varies from sand to sandy silt. Enrichment and Contamination factor analysis showed that these analyses can also be used to evaluate of deep sea environmental and source parameters. It is concluded that the biological and cold seep effects are the main drivers of surface sediment characteristics from the Anaximander mud volcanoes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Sensitivity of WRF-ARW for Heavy Precipitation Event over the Eastern Black Sea Region

    Science.gov (United States)

    Doǧan, Onur Hakan; Önol, Barış

    2017-04-01

    In this study, we examined the extreme summer precipitation case over the Eastern Black Sea region of Turkey by using WRF-ARW. 11 people were killed by the flood and many buildings were damaged by the landslides in Artvin province. The flood caused by heavy precipitation between August 23 and 24, 2015 and the station observation is 255 mm total precipitation for the two days. We have also used satellite based observational data (Global Precipitation Measurement: GPM), which represents 150 mm total precipitation during case, to validate precipitation simulations. We designed three nested domains with 27-9-3 km resolutions for the simulations and the inner domain covers the all Black Sea and the surrounded coasts. The simulations have been driven by ECMWF ERA-Interim data and the initial conditions have been generated for 4 different simulations which are 3-days, 7-days, 15-days and 25-days long. WRF-ARW model physics parameters have been tested to improve simulation capability for extreme precipitation events. The microphysics (Kessler and New-Thompson) and PBL (YSU PBL and Mellor-Yamada-Janjic) options have been applied for each simulations separately, therefore 15 sensitivity simulation have been analyzed by using different parametrizations. In general, all simulations underestimated the two days extreme precipitation event which the large scale flow interact with warmer sea surface temperatures and complex topography over the eastern Black Sea region. The 3-days simulation with Kessler microphysics and YSU PBL predicts 148 mm precipitation which is highest simulated precipitation compare to all simulations for the corresponding station location. Moreover 25-days simulation represents better spatial coverage for precipitation pattern compare to the GPM data.

  17. Physical and underway data collected aboard the OCEANUS during cruise OC454-02 in the Aegean Sea and Mediterranean Sea - Eastern Basin from 2009-07-28 to 2009-08-05 (NODC Accession 0104319)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104319 includes physical and underway data collected aboard the OCEANUS during cruise OC454-02 in the Aegean Sea and Mediterranean Sea - Eastern...

  18. Some biological parameters of Pagellus acarne (Risso, 1827 from the eastern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Branko Dragičević

    2015-11-01

    Full Text Available Pagellus acarne (Risso, 1827, although considered a common species, has never been a subject of biological research in the eastern Adriatic Sea. The aim of this study, conducted on 1188 specimens of this species in the period from 2007 – 2008 was to fill that gap. Here we present growth parameters, describe reproductive cycle and feeding habits of this species originating from the eastern Adriatic Sea. Age of the specimens was determined by direct reading of otoliths; the oldest male was 6 yerars old, and the oldest female 11 years old. Growth was described with von Bertalanffy model with following parameters: L ∞ = 27.0 cm, K = 0.29, t0 = -1.52, R2 = 0.902. This species is characterized by protandric hermaphroditism and its spawning period lasts from August to December. Hermaphroditic specimens were found in length classes from 16,1 to 25,5 cm. Females are characterized by relatively low fecundity. Length of the first maturity was 16,1 cm for males and 17,7 cm for females. Investigation of its feeding habits revealed that it feeds mainly on benthic invertebrates and its prey constitutes mainly of crustaceans and polychaetes. Feeding activity was highest in spring and lowest in winter.

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

    Directory of Open Access Journals (Sweden)

    Robert J. Miller

    2015-07-01

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

  20. Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific

    Science.gov (United States)

    Amorocho, Diego F.; Abreu-Grobois, F. Alberto; Dutton, Peter H.; Reina, Richard D.

    2012-01-01

    Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean. PMID:22319635

  1. The Teleconnection Between Atlantic Sea Surface Temperature and Eastern Pacific Tropical Cyclones

    Science.gov (United States)

    Patricola, C. M.; Saravanan, R.; Chang, P.

    2016-12-01

    The El Niño-Southern Oscillation (ENSO) is a major source of seasonal tropical cyclone (TC) predictability, in both local and remote ocean basins. Unusually warm eastern tropical Pacific sea-surface temperature (SST) during El Niño tends not only to enhance local TC activity in the eastern North Pacific (ENP) but also to suppress Atlantic TCs via well-known teleconnections. Here, we demonstrate that Atlantic SST variability likewise exerts a significant influence on remote TC activity in the eastern Pacific basin using observations and 27 km resolution tropical channel model simulations. Observed and simulated accumulated cyclone energy in the ENP is substantially reduced during the positive phase of the Atlantic Meridional Mode (AMM), which is characterized by warm and cool SST anomalies in the northern and southern tropical Atlantic respectively, and vice versa during the cool AMM phase. We find that the observed anti-correlation in seasonal TC activity between the Atlantic and ENP basins is driven by interannual climate variability in both the tropical Pacific (ENSO) and Atlantic (AMM). The physical mechanisms that drive the teleconnection between Atlantic SST and ENP TC activity will also be presented. This work provides information that can be used to improve seasonal forecasts and future projections of ENP tropical cyclone activity.

  2. The relationship between volatile halocarbons and phytoplankton pigments during a Trichodesmium bloom in the coastal eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Roy, R.; Pratihary, A.; Narvenkar, G.; Mochemadkar, S.; Gauns, M.; Naqvi, S.W.A.

    and 5 th April 2007 during regular visits to the Candolim Time Series (CaTS) station G3 located in the eastern Arabian Sea off Goa, India (Figure 1a). In order to investigate the phenomenon in detail and to extend the observations further offshore.... Chemosphere 45, 371-377. 14 Figure Captions Figure 1. a) Sampling locations in the eastern Arabian Sea off Goa; b) picture showing patchy Trichodesmium bloom observed at CaTS station G3. April. Figure 2. MODIS satellite observations from (showing...

  3. Coastal sea level variability in the eastern English Channel: Potentialities for future SWOT applicability

    Science.gov (United States)

    Turki, Imen; Laignel, Benoit; Chevalier, Laetitia; Costa, Stephane

    2014-05-01

    Scientists and engineers need to understand the sea level variability in order to provide better estimates of the sea level rise for coastal defense using tide gauges and radar altimetry missions. The natural limitation of the tide gauge records is their geographical sparsity and confinement to coastlines. The future Surface Water and Ocean Topography (SWOT) mission will be launched in 2015 over a period of 5 years and will be designated to address this issue. This research was carried out in the framework of the program Surface Water and Ocean Topography (SWOT) which is a partnership between NASA and CNES. Using a series of statistical analyses, we point to characterize the sea level variability in the eastern English Channel (western France) from four tide gauges in Dunkirk, Dieppe, Le Havre and Cherbourg for the period 1964-2012. To assess the extent to which tide gauge point observations represent tide gauge data, we compare tide gauge records to SWOT measurements in their vicinity. Results have shown that the bimodality of the sea level, provided by the distribution analysis, can be reproduced by SWOT measurements with an overestimation of both modes and also the extreme values. The rate of the linear regression was also overestimated from 1.7-4 mm/yr to 2.6-5.4 mm/yr. The continuous wavelet transform of sea level records has shown the large-scale variability of annual (1-year band) and interannual cycles (2-6- and 6-12-year bands) in sea level, which can be explained by oceanographic and hydrological factors. High frequency dynamics of the sea level variability at short time-scales were extracted from SWOT measurements. They provide a good survey of the surge events (band of 3-4 months) and the spring-neap tidal cycle (band of 28 days). Then, tide gauges should be used in conjunction with satellite data to infer the full time-scale variability. Further studies are needed to refine the SWOT applicability in coastal areas. Key words: coastal zone, sea level

  4. Discards of the purse seine fishery targeting small pelagic fish in the eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Konstantinos Tsagarakis

    2012-08-01

    Full Text Available We analysed data collected on board commercial purse seine vessels in the Aegean and Ionian Seas (eastern Mediterranean Sea, Greece in 13 seasonal sampling periods from 2003 to 2008 in order to describe the composition of the retained and discarded catch and shed light on discarding practices. In each area, five species constituted the majority of the marketable catch (> 97%: sardine (Sardina pilchardus, anchovy (Engraulis encrasicolus, round sardinella (Sardinella aurita, bogue (Boops boops (in both areas, mackerel (Scomber japonicus; in the Aegean Sea and picarel (Spicara smaris; in the Ionian Sea. Discarded quantities were on average 4.6% and 2.2% of the total catch in terms of weight in the Aegean and Ionian Seas respectively. Discards on the marketable ratio fluctuated over years and seasons without showing any particular trend. At the species level, sardine and mackerel were seldom discarded while large amounts of anchovy were discarded only during its recruitment period (autumn, when juvenile fish dominate the population. The discarding ratio for bogue, picarel and round sardinella ranged from zero to total discarding because they constitute a supplementary source of income for the fishers. Discarded fish comprised mainly small individuals for all species considered with the exception of round sardinella. However, the lengths at which 50% of the individuals were discarded were generally small, often smaller than the species minimum landing sizes. Geographical coordinates and marketable catch explained part of the variability of the discarded quantities, as revealed by generalized additive models. Discarding practices and implications for management of purse seine fisheries are also discussed.

  5. Progress of KOERI Tsunami Warning System for the Eastern Mediterranean, Aegean and Black Seas

    Science.gov (United States)

    Necmioglu, Ocal; Meral Ozel, Nurcan; Ozer Sozdinler, Ceren; Yilmazer, Mehmet; Cokacar, Tulay; Comoglu, Mustafa; Pinar, Ali; Kekovali, Kivanc

    2016-04-01

    This presentation provides a progress report on the activities of the Bogazici University / Kandilli Observatory and Earthquake Research Institute - Regional Earthquake and Tsunami Monitoring Center (KOERI-RETMC) which provides services as a Candidate Tsunami Service Provider (CTSP) of ICG/NEAMTWS in the Eastern Mediterranean, Aegean and Black Seas since 1 July 2012. KOERI continues to operate 178 BB and 97 strong motion and 6 short period sensors and the regional coverage includes 77 stations from GFZ and additional 16 stations through bilateral agreements. One radar-type tide-gauge has been installed in Fethiye within the framework of "Inexpensive Device for Sea-Level Measurement" (IDSL) initiative offered as donation by the EC/JRC and planning is in progress for the possible installation of three more IDSLs in selected locations in the Aegean Sea coast of Turkey. The capabilities and the limitations of HF Radar technology for the purpose of tsunami detection in the Eastern Mediterranean has been identified and the maturity and the applicability of these systems for the possible use under the Tsunami Warning System has been determined. The development of the TsuComp as a user-friendly interface to be used in the assessment of tsunamigenic potential and as a single-point entry for message dissemination has been finalized. The work towards the creation of Tsunami Inundation Maps at the Tsunami Forecast Points in Turkey is near finalization. This work is partially funded by project ASTARTE - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839. The authors would like to thank EC/JRC and Mr. Alessandro Annunziato for their continuous support in the operational activities of RETMC and IDSL initiative.

  6. Sea Surface Temperatures in the Eastern Equatorial Pacific and Surface Temperatures in the Eastern Cordillera of Colombia During El Niño: Implications for Pliocene Conditions

    Science.gov (United States)

    Pérez-Angel, Lina C.; Molnar, Peter

    2017-11-01

    Regressions of surface temperatures in the Eastern Cordillera of Colombia with sea surface temperatures (SSTs) in the equatorial Pacific, and specifically with Niño1+2 and Niño3 temperature anomalies, show that the Eastern Cordillera warms or cools by approximately half of the amplitude of the variation of SSTs in the eastern tropical Pacific. Because Pliocene SSTs in the eastern tropical Pacific resemble those during major El Niño events, when SSTs warm by 4°C, these regressions suggest that the Pliocene Eastern Cordillera was warmer by 2°C at both high and low elevations. Such post-Pliocene cooling is smaller than the 9-12°C inferred from fossil pollen assemblages, but comparable to recent estimates of Anderson et al. of 3 ± 1°C (1σ) since 8 Ma. This change in surface temperature could be explained by a change in regional climate associated with a different tropical Pacific SST distribution and therefore would require neither an elevation change of the Eastern Cordillera since that time nor a change between Pliocene and present-day temperatures in the tropics that is as large as estimates of the global change of 2.5-4°C.

  7. Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic

    Directory of Open Access Journals (Sweden)

    S. GARCIA-SANZ

    2014-03-01

    Full Text Available Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula at Gran Canaria Island (eastern Atlantic via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula with the most conspicuous species (D. africanum in the study area.

  8. Open ocean DMS air/sea fluxes over the eastern South Pacific Ocean

    Science.gov (United States)

    Marandino, C. A.; de Bruyn, W. J.; Miller, S. D.; Saltzman, E. S.

    2009-01-01

    Air/sea fluxes of dimethylsulfide (DMS) were measured by eddy correlation over the Eastern South Pacific Ocean during January 2006. The cruise track extended from Manzanillo, Mexico, along 110° W, to Punta Arenas, Chile. Bulk air and surface ocean DMS levels were also measured and gas transfer coefficients (kDMS) were computed. Air and seawater DMS measurements were made using chemical ionization mass spectrometry (API-CIMS) and a gas/liquid membrane equilibrator. Mean surface seawater DMS concentrations were 3.8±2.2 nM and atmospheric mixing ratios were 340±370 ppt. The air/sea flux of DMS was uniformly out of the ocean, with an average value of 12±15 μmol m-2 d-1. Sea surface concentration and flux were highest around 15° S, in a region influenced by shelf waters and lowest around 25° S, in low chlorophyll gyre waters. The DMS gas transfer coefficient exhibited a linear wind speed-dependence over the wind speed range of 1 to 9 m s-1. This relationship is compared with previously measured estimates of k from DMS, CO2, and dual tracer data from the Atlantic and Pacific Ocean, and with the NOAA/COARE gas transfer model. The model generated slope of k vs. wind speed is at the low end of those observed in previous DMS field studies.

  9. Three Anisakis spp. isolated from toothed whales stranded along the eastern Adriatic Sea coast.

    Science.gov (United States)

    Blažeković, Kristina; Pleić, Ivana Lepen; Đuras, Martina; Gomerčić, Tomislav; Mladineo, Ivona

    2015-01-01

    Knowledge concerning cetacean ecology in the Mediterranean is limited but important for sustainable planning and enforcement of appropriate conservation measures. Any information that might help to elucidate their ecology is essential. We explored the population and genetic structures of Anisakis spp. nematodes isolated from four toothed whale species - bottlenose dolphins (Tursiops truncatus), striped dolphins (Stenella coeruleoalba), Risso's dolphins (Grampus griseus) and Cuvier's beaked whales (Ziphius cavirostris) - stranded along the eastern Adriatic Sea coast (1990-2012) to reveal more information on host ecological patterns. Lower parasite prevalence was observed in resident dolphin species compared with occasionally occurring species, as well as in young compared with adult dolphins, indicating different feeding habits related to age. No unequivocal relationship between the biological traits of a host (age, body length, body mass and blubber depth) and Anisakis population parameters was observed. Phylogenetic analysis revealed a new geographical record of Anisakis simplex sensu stricto (1.96%) and Anisakis physeteris (1.31%) in the Adriatic Sea in addition to resident Anisakis pegreffii (96.73%). In an assessment of the Adriatic Sea and oceans worldwide, the genetic structure of Anisakis revealed that A. pegreffii populations do not differ among various final host species but do differ with respect to geographical location in contrast to previously accepted Anisakis panmixia. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  10. Distribution of atmospheric CH4 concentration in eastern margin of Japan Sea from 7K14 cruises

    Science.gov (United States)

    Aoki, S.; Komiya, S.; Noborio, K.; Matsumoto, R.

    2015-12-01

    Hydrate of natural gas is widely distributed in marine sediments in the eastern margin of Japan Sea. Active gas vents from the seafloor have previously been reported worldwide at gas hydrate fields. Atmospheric methane (CH4), a major component of seep gases, is an important short-lived climate pollutant. Gas seeps may contribute to increase atmospheric gas concentration above the sea surface. Our objectives were to continuously measure and investigate the distribution of the atmospheric CH4 concentration over the sea surface at the gas hydrate fields along the eastern margin of Japan Sea. We used the R/V Kaiyo-Maru No.7 (Kaiyo Engineering Co., Ltd., Japan) for the survey in Japan Sea from mid April to early June 2014. Continuous measurement of atmospheric CH4 was performed on the ship using a wave-length-scanned cavity ring-down spectrometer (WS-CRDS) (model G2201-i, Picarro Inc., USA). Air sample was collected from an air intake at the top deck (approximately 8 m above sea level) of the ship using an air pump placed in the observation room. To our experience, the ship sailed at approximately 6 knot. Location data were obtained with the nautical GPS. Observed atmospheric CH4 concentration over the sea surface was approximately between 1.8-1.9 ppm in most sea areas, but exceeds 2.0 ppm in some areas. This study was conducted as a part of the METI's shallow gas hydrate exploration project.

  11. Opportunism on the High Seas: Foraging Ecology of Olive Ridley Turtles in the Eastern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Lindsey E. Peavey

    2017-11-01

    Full Text Available Stable isotopic compositions in animal tissues have been widely used to gain insight into trophic dynamics, especially of mobile aquatic predators whose behavior and dietary preferences are difficult to directly measure. Olive ridley sea turtles (Lepidochelys olivacea range across >3 million km2 of the tropical and subtropical eastern Pacific Ocean and their trophic ecology in open ocean areas has not yet been adequately described. Individuals feed within biogeographic regions where varying nutrient cycling regimes result in phytoplankton with distinct δ13C and δ15N values that are assimilated by the turtles. We sampled 346 turtles at-sea between 2003 and 2009 and used bulk tissue (n = 346 and amino acid compound specific isotope analysis (AA-CSIA, n = 31 to empirically support the conventional understanding that olive ridleys are omnivores. Bulk δ15N values did not significantly vary with carapace length, a proxy for age, or with putative sex of adults. We therefore hypothesize that trophic position (TP does not vary across age or sex. In line with other isotopic studies of this biogeographic scale in the same region, we observed a trend of bulk tissue 15N enrichment with increasing latitude. Using AA-CSIA to account for δ15N baseline shifts among food webs (space, we estimated the TP of adult foragers using two methods. We found that across their eastern Pacific range, olive ridley δ13C and δ15N niche area varied, but median TP of adults remained constant (~3.1. Using a two-amino acid TP estimation method, we detected a small but notable elevation of TP for olive ridleys on the Costa Rica Dome. This study underscores the value of large-scale in-water olive ridley sea turtle research across oceanic foraging habitats to confirm or challenge anecdotal understanding of trophic roles, susceptibility to environmental change, and critical habitats. Further, it improves our understanding of why this species is now abundant in the eastern Pacific

  12. Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily, Central Mediterranean Sea.

    Science.gov (United States)

    Sciacca, Virginia; Caruso, Francesco; Beranzoli, Laura; Chierici, Francesco; De Domenico, Emilio; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Larosa, Giuseppina; Marinaro, Giuditta; Papale, Elena; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Simeone, Francesco; Viola, Salvatore; Riccobene, Giorgio

    2015-01-01

    In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, "NEMO-SN1", deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz-1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9-22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.

  13. Annual Acoustic Presence of Fin Whale (Balaenoptera physalus Offshore Eastern Sicily, Central Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Virginia Sciacca

    Full Text Available In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea, throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, "NEMO-SN1", deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz-1 kHz, sampling rate: 2 kHz which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9-22.5 Hz was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.

  14. Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily, Central Mediterranean Sea

    Science.gov (United States)

    Sciacca, Virginia; Caruso, Francesco; Beranzoli, Laura; Chierici, Francesco; De Domenico, Emilio; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Larosa, Giuseppina; Marinaro, Giuditta; Papale, Elena; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Simeone, Francesco; Viola, Salvatore; Riccobene, Giorgio

    2015-01-01

    In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise. PMID:26581104

  15. Comparison of ERA-Interim waves with buoy data in the eastern Arabian Sea during high waves

    Digital Repository Service at National Institute of Oceanography (India)

    Shanas, P.R.; SanilKumar, V.

    at two locations in eastern Arabian Sea One location is a deep water location and another one is a shallow water location The comparison of significant wave height (SWH) between ERA dataset and buoy data at both the locations shows good correlation...

  16. Vertical distributions and speciation of dissolved rare earth elements in the anoxic brines of Bannock Basin, eastern Mediterranean Sea

    NARCIS (Netherlands)

    Schijf, Johan; Baar, Hein J.W. de; Millero, Frank J.; Byrne, R.H.

    1995-01-01

    Vertical distributions of dissolved rare earth elements (REEs) are presented for the anoxic, highly sulfidic brines of Bannock Basin in the eastern Mediterranean Sea. REE concentrations at the seawater-brine interface are the highest ever recorded in the water column of an anoxic basin and

  17. On an upwelling front, propagation of upwelling and vertical velocity in the eastern Arabian sea during monsoon, 1987

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, M.K.; Unnikrishnan, A.S.

    A coastal upwelling front parallel to the coast and identifiable upto a depth of 75 m was observed between 12.5 and 16 degrees N along the eastern Arabian Sea in September, 1987 from closely spaced digital BT data. With a north-south slope...

  18. Life at cold seeps : a synthesis of biogeochemical and ecological data from Kazan mud volcano, eastern Mediterranean Sea

    NARCIS (Netherlands)

    Werne, JP; Haese, RR; Zitter, T; Aloisi, G; Bouloubassi, L; Heijs, S; Fiala-Medioni, A; Pancost, RD; Damste, JSS; de Lange, G; Forney, LJ; Gottschal, JC; Foucher, JP; Mascle, J; Woodside, J

    2004-01-01

    Recent field observations have identified the widespread occurrence of fluid seepage through the eastern Mediterranean Sea floor in association with mud volcanism or along deep faults. Gas hydrates and methane seeps are frequently found in cold seep areas and were anticipated targets of the

  19. Temporal and spatial variations in provenance of Eastern Mediterranean Sea sediments: Implications for Aegean and Aeolian arc volcanism

    NARCIS (Netherlands)

    Klaver, M.; Djuly, T.; de Graaf, S.; Sakes, A.; Wijbrans, J.R.; Davies, G.R.; Vroon, P.Z.

    2015-01-01

    The Eastern Mediterranean Sea (EMS) is the last remnant of the Tethys Ocean that has been subducted to the north since the Jurassic. Subduction has led to the formation of multiple island arcs in the EMS region where the Aeolian and Aegean arcs are currently active. The EMS is surrounded by

  20. Offshore limit of coastal ocean variability identified from hydrography and altimeter data in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, M.K.; Swamy, G.N.; Somayajulu, Y.K.

    /Poseidon) information. Vertical sections of temperature from two contrasting seasons - south-west (SW) and north-east (NE) monsoons - when projected together are found to intersect offshore at 350-400 km from the coast along a transect in the eastern Arabian Sea during...

  1. Early- to late-Holocene contrast in productivity, OMZ intensity and calcite dissolution in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Godad, S.P.; Naidu, P.D.; Tiwari, M.; Paropkari, A.L.

    , vol.24(6); 2014; 749-755 Early to Late Holocene Contrast in productivity, OMZ Intensity and Calcite Dissolution in the Eastern Arabian Sea Sushant S. Naik*,1, Shital P. Godad2, P. Divakar Naidu3, Manish Tiwari4, A. L. Paropkari5 1,2,3,5 CSIR...

  2. Gouge marks on deep-sea mud volcanoes in the eastern Mediterranean: Caused by Cuvier’s beaked whales?

    NARCIS (Netherlands)

    Woodside, J.M.; David, L; Frantzis, A.; Hooker, S.K.

    2006-01-01

    Enigmatic seafloor gouge marks at depths of 1700-2100 m have been observed from submersible during geological survey work studying mud volcanoes in the eastern Mediterranean Sea. The marks consist of a central groove (about 10 cm deep and 1-2 m long), superimposed on a broader bowl-shaped depression

  3. Methane-related authigenic carbonates of the eastern Mediterranean Sea mud volcanoes and their possible relation to gas hydrate destabilisation

    NARCIS (Netherlands)

    Aloisi, G; Pierre, C; Rouchy, J.-M.; Foucher, J.P.; Woodside, J.M.; MEDINAUT scientific party, NN

    2000-01-01

    Nautile submersible investigations of mud volcanoes and brine seep areas of the eastern Mediterranean Sea during the MEDINAUT cruise in November 1998 discovered extensive areas of authigenic carbonate crusts associated with methane emissions. Carbonate crusts form pavements, round slabs and circular

  4. Life at cold seeps: a synthesis of biogeochemical and ecological data from Kazan mud volcano, eastern Mediterranean Sea

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Werne, J.P.; Zitter, T.; Haese, R.R.; Aloisi, G.; Bouloubassi, I.; Heijs, S.; Fiala-Medioni, A.; Pancost, R.D.; Lange, G.J. de; Gottschal, J.; Foucher, J.-P.; Mascle, J.; Woodside, J.

    2004-01-01

    Recent field observations have identified the widespread occurrence of fluid seepage through the eastern Mediterranean Sea floor in association with mud volcanism or along deep faults. Gas hydrates and methane seeps are frequently found in cold seep areas and were anticipated targets of the

  5. On the climatological mean circulation over the eastern Bering Sea shelf

    Science.gov (United States)

    Reed, R. K.; Stabeno, P. J.

    1996-08-01

    We derive climatological mean summer circulation over the eastern Bering Sea shelf. Geostrophic flow (from CTD data, 1975-1989) and drifter velocities (from satellite-tracked buoys, 1986-1994) were used. The following features are shown: (1) in depths >100 m, a northwestward flow of ˜4 cm s -1, which is largely baroclinic; (2) near the 50 m isobath, a flow of ˜2 cm s -1 , which is only partially baroclinic; and (3) a semi-permanent, convoluted flow of 1-2 cm s -1, between the 100 and 50 m isobaths, that was not recognized in earlier analyses. Data from current moorings indicate that there is no significant tidal enhancement of net flow on the shelf as earlier suggested. This new climatology also shows clearly a divergence of the inflow through Unimak Pass, and it suggests that the shelf salinity distribution is influenced by advection as well as diffusion.

  6. Isotopic characteristics of shells Mytilus galloprovincialis from eastern coastal area of Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Tjaša Kanduč

    2006-06-01

    Full Text Available Samples of Mytilus galloprovincialis were collected from entire Eastern Adriatic coast to determine δ18O and δ13C performed on calcite and aragonite shell layers. The aim of this work was to check whether shells of M. galloprovincialis are good environmental indicators (water temperature, salinity. Based on measured isotopic composition of oxygen in shell layers and assumed isotopic composition in water temperatures of calcite and aragonite of shell layers were calculated. The calculated temperatures for M. galloprovincialis shell growth of calcite and aragonite shell layer are in good agreement with measured temperatures of sea water. According to our results of δ18O and δ13C in shell layers we canseparate the locations of the investigated area into three groups: those with more influence of fresh water, those with less influence of fresh water and those of marine environments.

  7. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

    KAUST Repository

    Tsiola, A.

    2015-12-01

    The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.

  8. LATE PLIOCENE-HOLOCENE DEBRIS FLOW DEPOSITS IN THE IONIAN SEA (EASTERN MEDITERRANEAN

    Directory of Open Access Journals (Sweden)

    GIOVANNI ALOISI DE LARDEREL

    1997-11-01

    Full Text Available Widespread coring of the Eastern Mediterranean Basin has outlined the existence of a systematic relation between lithology of debris flow deposits and physiographic setting. Whilst the topographic highs are characterized by pelagic sedimentation, the basin floors are alternatively subject to pelagic sedimentation and re-sedimentation pro cesses. Amongst the latters, turbidity flows and debris flows are the most common transport mechanisms.In this paper we present the study of the debris flow pro cess in the Ionian Sea using visual description of cores, grain size, carbonate content and smear slide analysis carried out on gravity and piston cores recovered over the past 20 years. A distinction has been made between debris flow deposits originating from the continental margins (North Africa and Malta Escarpment and those emplaced in the small basins amidst the Calabrian and Mediterranean ridges "Cobblestone Topography". As a result of the difference in setting, the former debris flow deposits include a great variety of lithologies and ages whilst the latter involve the pelagic sediments forming the typical Eastern Mediterranean Plio-Quaternary succession. A detailed study of clast and matrix structures makes it possible to describe the flows in terms of existing classifications of sediment gravity flows and to assume a clast support mechanism. Finally, biostratigraphy coupled with the presence of widespread marker beds enabled us to estimate the age of emplacement of the deposits and to hypothesize a triggering mechanism for flow initiation. Three flows are strictly related to the pelagic turbidite named homogenite, triggered by the explosive eruption of the Santorini volcano (Minoan eruption and therefore have an estimated age of 3,500 BP. The other deposits have ages ranging from 9,000 BP to about 70,000 BP and were originated by debris flows triggered by events such as earthquakes and glacial low sea level stands.    

  9. Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda from Lebanon

    Directory of Open Access Journals (Sweden)

    F. CROCETTA

    2013-07-01

    Full Text Available A reviewed knowledge of the opisthobranch species from Lebanon (eastern Mediterranean Sea, based on literature records (scattered throughout various papers published over a period of more than 150 years and recently collected material (1999-2002 within the CEDRE framework and other samples, is presented, yielding a total number of 35 taxa recorded from the Lebanese shores identified to species level. Special emphasis has mainly been given to the alien species, for which scattered notes are also given. The known opisthobranch biota is composed of 22 native (~ 63%, 12 alien (~ 34% and one cryptogenic (~ 3% taxa. Eleven of these (Berthella aurantiaca, B. ocellata, Aplysia fasciata, Felimare picta, Felimida britoi, F. luteorosea, F. purpurea, Phyllidia flava, Dendrodoris grandiflora, D. limbata and Aeolidiella alderi constitute new records for the Lebanese fauna, whilst the examined material of a further seven species (Elysia grandifolia, Pleurobranchus forskalii, Aplysia dactylomela, Bursatella leachii, Syphonota geographica, Goniobranchus annulatus, Flabellina rubrolineata anecdotally cited from Lebanon on the basis of the samples here studied, is here first explained. One additional taxon belonging to the genus Haminoea has been identified to genus level only. Despite the searching effort poning the basis of the material analyzed here, data reported clearly suggest that strong investments are still needed for a better understanding of the eastern Mediterranean opisthobranch fauna.

  10. Subsidence history of the eastern Northern South Yellow Sea Basin, offshore Korea

    Science.gov (United States)

    Lee, Eunyoung

    2010-05-01

    The Northern South Yellow Sea Basin (NSYSB) is located between East China and West Korea, and is one of the basins in eastern Asia where rifting started in the late Mesozoic time, caused by large-scale interaction between the Pacific, Eurasian, and Indian plates. To analyze the detailed tectonic evolution of this basin, this study focuses on backstripping the subsidence history of four representative structures selected in the basin. This paper examines sag and half-graben structures in the Central Sub-basin as well as half-graben and graben structures in the SW Sub-basin. By sedimentary backstripping, the subsidence history of the eastern NSYSB can be grouped into a main subsidence phase in the Late Cretaceous - Oligocene and a secondary subsidence phase in the Middle Miocene - present. Both subsidence phases are separated by the uplift and erosion phase during Early Miocene times. The main subsidence phase itself consists of a rapid subsidence in the Late Cretaceous - Paleocene and a slow subsidence phases in the Eocene - Oligocene. These subsidence phases of this basin can be correlated to MSQ I, II and III identified in the SW Sub-basin with seismic stratigraphy, and can further be related to the convergence movement of Pacific-Eurasia and Indian-Eurasia plates.

  11. Indications of low macrobenthic activity in the deep sediments of the eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Daniela Basso

    2004-12-01

    Full Text Available The fluxes and budget of organic matter from the oligotrophic surface waters of the eastern Mediterranean to the deep waters are poorly known, and little information is available on past and present macrobenthic activity on the sea floor. Evidence of macrobenthic activity can be direct, through recovery of living organisms or their autochthonous skeletal remains, or indirect, through bioturbation and trace fossils. The evidence of biological activity in deep eastern Mediterranean sediments has been evaluated and compared through 210Pb profiles from box-cores and study of dredge samples from sites on Medina Rise (1374 m water depth, the Messina Abyssal Plain (4135 m and several sites along the Mediterranean Ridge, SW and S of Crete (1783 to 3655 m. All these sites are remote from the continental shelves, so the biological benthic activity is expected to depend primarily on primary production from surface waters. The results show that present-day macrobenthos and trace fossils are generally scarce, especially at depths > 2500 m. This observation is supported by surface sediment 210Pb excess distributions that show a surface mixed layer (SML 2500 m. The historical layer of some box-cores and the Pleistocene hardgrounds collected in the Cleft area (Mediterranean Ridge do, however, record a macrobenthic activity that is apparently more intense than at present, which may be related to higher primary production of the Pleistocene glacial intervals. In contrast with most areas of the present-day deep eastern Mediterranean which depend on surface primary production based on photosynthesis, a relatively dense and diversified macrobenthic community based on chemosynthesis has been recognised at depths > 1100 m on the Napoli Dome mud volcano in the Olimpi area, and on the Kazan and other mud volcanoes in the Anaximander Mountains.

  12. Lithospheric Response of the Anatolian Plateau in the Realm of the Black Sea and the Eastern Mediterranean

    Science.gov (United States)

    Ergun, Mustafa

    2016-04-01

    The Eastern Mediterranean and the Middle East make up the southern boundary of the Tethys Ocean for the last 200 Ma by the disintegration of the Pangaea and closure of the Tethys Ocean. It covers the structures: Hellenic and Cyprus arcs; Eastern Anatolian Fault Zone; Bitlis Suture Zone and Zagros Mountains. The northern boundary of the Tethys Ocean is made up the Black Sea and the Caspian Sea, and it extends up to Po valley towards the west (Pontides, Caucasus). Between these two zones the Alp-Himalayan orogenic belt is situated where the Balkan, Anatolia and the Iran plateaus are placed as the remnants of the lost Ocean of the Tethys. The active tectonics of the eastern Mediterranean is the consequences of the convergence between the Africa, Arabian plates in the south and the Eurasian plate in the north. These plates act as converging jaws of vise forming a crustal mosaic in between. The active crustal deformation pattern reveals two N-S trending maximum compression or crustal shortening syntaxes': (i) the eastern Black Sea and the Arabian plate, (ii) the western Black Sea and the Isparta Angle. The transition in young mountain belts, from ocean crust through the agglomeration of arc systems with long histories of oceanic closures, to a continental hinterland is well exemplified by the plate margin in the eastern Mediterranean. The boundary between the African plate and the Aegean/Anatolian microplate is in the process of transition from subduction to collision along the Cyprus Arc. Since the Black Sea has oceanic lithosphere, it is actually a separate plate. However it can be considered as a block, because the Black Sea is a trapped oceanic basin that cannot move freely within the Eurasian Plate. Lying towards the northern margin of orogenic belts related to the closure of the Tethys Ocean, it is generally considered to be a result of back-arc extension associated with the northward subduction of the Tethyan plate to the south. Interface oceanic lithosphere at

  13. From Space to Seafloor - Investigating Oil and Gas Seepage in the Eastern Black Sea

    Science.gov (United States)

    Körber, J.; Sahling, H.; Pape, T.; Heygster, G.; Bohrmann, G.

    2011-12-01

    Emissions of gases from the seafloor are of interest due to their relevance for the global climate, their potential as energy source, and impact on geochemical and biogeochemical cycles. Gas seepage has previously been reported to occur along the continental margin, on the shelf, and at some locations in the central deep Black Sea. These discoveries led to the assumption that seepage of light hydrocarbons from the seafloor is one of the major sources feeding the high methane concentrations of the Black Sea water body. It is commonly accepted that the proportion of pure bubble-forming methane released from deep-sea seeps reaching the hydrosphere/atmosphere interface is negligible since it is nearly entirely dissolved during its ascent through the water column or it is replaced by other gases diffusing from the water column into the bubbles. However, there is first evidence from recent studies at seeps showing intimate seepage of oil and gas that oil coatings around gas bubbles might protect the methane from complete dissolution. A set of Advanced Synthetic Aperture Radar (ASAR) satellite images has been analysed in order to detect oil slicks as sea surface expressions of natural seepage in the deep eastern Black Sea off Georgia. Eight oil seep sites located between 450 and 1200 m water depth have been identified. Intensive hydroacoustic seafloor and water column investigations during two ship expeditions in 2010 and 2011 in combination with shallow sediment sampling and evaluation of hydroacoustic data from earlier cruises confirmed seepage of oil and gas. Ratios of thermogenic and biogenic gas vary significantly between the oil and gas seeps (e.g. Pechori Mound) and pure gas seeps (e.g. Batumi seep). Oil seeps seem to be related to ridge structures and underlying shale diapirs originating from the hydrocarbon rich Oligocene-Miocene Maikop formation. High resolution mapping of the Colkheti Seep (1125 mbsl), one of the most prominent oil seeps off Georgia, using an

  14. Nitrification rates, nitrite and nitrate distribution in the Almeria-Oran frontal systems (eastern Alboran Sea)

    Science.gov (United States)

    Bianchi, M.; Morin, P.; Le Corre, P.

    1994-08-01

    In the western Mediterranean Sea, the Almeria-Oran frontal zone constitutes the eastern boundary of the Alboran Sea. During the "Almofront-1" cruise (April-May 1991) physical, chemical and biological features of the front and surrounding Atlantic and Mediterranean Waters were investigated. In the present study, the nitrite and nitrate concentrations and nitrification rates were measured. The nitracline was close to the surface in the north, close to the Spanish coast and in the south on the left side of the jet. The highest concentration of nitrite (0.25 μM) was located in the incoming Atlantic Waters. The ammonium oxidation rates were from 0 to 16 nmol 1 -1 d -1, except in Atlantic Waters in which the rates reached 28-42 nmol 1 -1 d -1. For all types of superficial water, i.e. Atlantic, jet core, Mediterranean, the nitrite produced by nitrification could account for the in situ concentrations in less time than the ages of the water masses. In contrast, to reach the ambient concentration, the production of nitrate would need more time than the lifetime of the water masses, except for the Atlantic Waters. In these Atlantic Waters, showing an increased rate of nitrate production, the in situ concentration of nitrate would be reached within its lifetime. The contribution of the nitrate produced by nitrification to the nitrate uptake by primary producers was estimated to range from 7% (Mediterranean Waters) to 40% (Atlantic Waters).

  15. Rapid Response of Eastern Mediterranean Deep Sea Microbial Communities to Oil

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiang; Techtmann, Stephen M.; Woo, Hannah L.; Ning, Daliang; Fortney, Julian L.; Hazen, Terry C.

    2017-07-18

    Deep marine oil spills like the Deepwater Horizon (DWH) in the Gulf of Mexico have the potential to drastically impact marine systems. Crude oil contamination in marine systems remains a concern, especially for countries around the Mediterranean Sea with off shore oil production. The goal of this study was to investigate the response of indigenous microbial communities to crude oil in the deep Eastern Mediterranean Sea (E. Med.) water column and to minimize potential bias associated with storage and shifts in microbial community structure from sample storage. 16S rRNA amplicon sequencing was combined with GeoChip metagenomic analysis to monitor the microbial community changes to the crude oil and dispersant in on-ship microcosms set up immediately after water collection. After 3 days of incubation at 14 °C, the microbial communities from two different water depths: 824 m and 1210 m became dominated by well-known oil degrading bacteria. The archaeal population and the overall microbial community diversity drastically decreased. Similarly, GeoChip metagenomic analysis revealed a tremendous enrichment of genes related to oil biodegradation, which was consistent with the results from the DWH oil spill. These results highlight a rapid microbial adaption to oil contamination in the deep E. Med., and indicate strong oil biodegradation potentia

  16. Assessment of Eutrophication Quality in Greek Coastal Ecosystem (Eastern Mediterranean Sea)

    Science.gov (United States)

    Pavlidou, Alexandra; Rousselaki, Eleni; Assimakopoulou, Georgia; Tsapakis, Manolis; Simboura, Nomiki

    2014-05-01

    The Mediterranean Sea has always been considered as one of the most oligotrophic areas in the world, especially in the Eastern part of the Sea. However, eutrophication problems occur in some coastal areas of the Mediterranean (e.g. eastern coasts of Spain, Gulf of Lions, northern Adriatic Sea, Apulian coasts, Saronikos Gulf, Thessaloniki Bay, northern coasts of Greece, etc.). This work is focused on the assessment of the Eutrophication Quality in different coastal areas of Greece affected by various anthropogenic and natural pressures and was performed under the Water Framework Directive. A network of 28 sampling stations was used during two relevant sampling periods, April - May 2012 and March - April 2013, in the framework of the National Monitoring Project of Greece. The Eutrophication assessment method integrates chemical and biological parameters of the water column. A synthetic Eutrophication Index (E.I.) was produced for the greek coastal areas by Primpas et al. quality classification scheme, combining the concentrations of nutrients (phosphate, nitrate, nitrite, ammonia) and chlorophyll-α biomass into a single formula. The E.I. assesses the eutrophication status using a five scale scheme according to the requirements of WFD: (High) less than 0.04; (Good) 0.04-0.38; (moderate) 0.38-0.85; (poor) 0.85-1.51; (bad) >1.51. Nutrient and chlorophyll-a concentrations revealed significant spatial variation among the various coastal areas of Greece influenced by different point and/or diffuse anthropogenic pressures (related to nutrient enrichment), reflecting the level of human-induced impairment where an increase in nutrient loads leads to increased water quality problems. The assessment of E.I showed that during 2012, 32% of the selected coastal areas were characterized as Good, 54% as Moderate and 14% of the selected greek coastal areas were characterized as Poor. During 2012, none of the study areas corresponded to High or Bad eutrophication status. During 2013

  17. Evidence of increased toxic Alexandrium tamarense dinoflagellate blooms in the eastern Bering Sea in the summers of 2004 and 2005.

    Directory of Open Access Journals (Sweden)

    Masafumi Natsuike

    Full Text Available The eastern Bering Sea has a vast continental shelf, which contains various endangered marine mammals and large fishery resources. Recently, high numbers of toxic A. tamarense resting cysts were found in the bottom sediment surface of the eastern Bering Sea shelf, suggesting that the blooms have recently occurred. However, little is known about the presence of A. tamarense vegetative cells in the eastern Bering Sea. This study's goals were to detect the occurrence of A. tamarense vegetative cells on the eastern Bering Sea shelf and to find a relationship between environmental factors and their presence. Inter-annual field surveys were conducted to detect A. tamarense cells and environmental factors, such as nutrients, salinity, chlorophyll a, and water temperature, along a transect line on the eastern Bering Sea shelf during the summers of 2004, 2005, 2006, 2009, 2012, and 2013. A. tamarense vegetative cells were detected during every sampling year, and their quantities varied greatly from year to year. The maximum cell densities of A. tamarense observed during the summers of 2004 and 2005 were much higher than the Paralytic shellfish poisoning warning levels, which are greater than 100-1,000 cells L-1, in other subarctic areas. Lower quantities of the species occurred during the summers of 2009, 2012, and 2013. A significant positive correlation between A. tamarense quantity and water temperature and significant negative correlations between A. tamarense quantity and nutrient concentrations (of phosphate, silicate, and nitrite and nitrate were detected in every sampling period. The surface- and bottom-water temperatures varied significantly from year to year, suggesting that water temperatures, which have been known to affect the cell growth and cyst germination of A. tamarense, might have affected the cells' quantities in the eastern Bering Sea each summer. Thus, an increase in the Bering Sea shelf's water temperature during the summer will

  18. Seismic stratigraphy and depositional history of late Quaternary deposits at the eastern Yellow Sea shelf

    Science.gov (United States)

    Yoo, Dong-Geun; Lee, Gwang-Soo; Kim, Gil-Young; Chang, Se-Won; Kim, Kyoung-Jin

    2017-04-01

    The late Quaternary stratigraphy and sedimentation at the eastern Yellow Sea shelf was studied using a dense network of high-resolution, single-channel seismic reflection profiles and sediment data. The shelf sequence in this area consists of six seismic units formed since the LGM. During the LGM, the study area was completely exposed, resulting in subaerial erosion associated with paleo-channel incision by the Huanghe and Korean Rivers. As the shelf was flooded, the incised channels were backfilled fluvial or coastal sediments, forming incised channel-fill deposits (SU1). The paleo-river may have supplied abundant terrigenous sediments to the study area around the paleo-river mouth and adjacent area. These sediments were trapped within the paleo-estuary and formed SU2, regarded as an estuarine deposit. Two types of serial sand ridges (SU3 and SU5) which correspond to transgressive deposits developed. SU3 on the southern part, west of Jeju Island (80 110 m deep) is regarded as a moribund-type mainly formed during the early to middle stage of transgression. These are thought to have ceased growing and remobilizing. In contrast, SU5 (occurring 30 50 m deep off the Korean Peninsula) is generally regarded as active sand ridges deposited during the late stage of transgression and is partly modified by modern tidal currents. As the transgression continued, the near-surface sediments were reworked and redistributed by shelf erosion, resulting in a thin veneer of transgressive sands (SU4). The uppermost unit (SU6) formed the Heuksan Mud Belt (HMB), which is one of the most prominent mud deposits in the Yellow Sea. The lower part of the HMD corresponds to shelf-mud deposited during the late stage of transgression, whereas the upper part consists of a recent shelf-delta developed after the highstand sea level at about 7 ka BP.

  19. Red Sea rift-related Quseir basalts, central Eastern Desert, Egypt: Petrogenesis and tectonic processes

    Science.gov (United States)

    Farahat, Esam S.; Ali, Shehata; Hauzenberger, Christoph

    2017-01-01

    Mineral and whole-rock chemistry of Red Sea rift-related Tertiary basalts from south Quseir city, central Eastern Desert of Egypt is presented to investigate their petrogenesis and relationship to tectonic processes. The south Quseir basalts (SQB) are classified as high-Ti (TiO2 >2 wt.%) subalkaline transitional lava emplaced in an anorogenic tectonic setting. Their Mg# varies from 48 to 53 indicating the evolved nature of the SQB. Pearce element ratios suggest that the SQB magmas evolved via fractional crystallization of olivine + clinopyroxene ± plagioclase, but the absence of Eu anomalies argues against significant plagioclase fractionation. Clinopyroxene compositions provide evidence for polybaric fractionation of the parental mafic magmas. Estimated temperatures of crystallization are 1015 to 1207 °C for clinopyroxene and 1076 to 1155 °C for plagioclase. These values are interpreted to result from early stage crystallization of clinopyroxene followed by concurrent crystallization of clinopyroxene and plagioclase. The incompatible trace element signatures of the SQB (La/Ba = 0.08-0.10 and La/Nb = 0.89-1.04) are comparable to those of ocean island basalts (OIB) generated from an asthenospheric mantle source unaffected by subduction components. Modeling calculations indicate that the SQB primary magmas were derived from 4-5% partial melting of a garnet-bearing lherzolite mantle source. The NE Egyptian basaltic volcanism is spatially and temporally related to Red Sea rifting and to the local E-W striking faults, confirming a relationship to tectonic activity. Our results suggest that the extensional regime associated with Red Sea rifting controlled the generation of the Egyptian basalts, likely as a result of passive upwelling of asthenospheric mantle.

  20. Numerical modelling of the buoyant marine microplastics in the South-Eastern Baltic Sea

    Science.gov (United States)

    Bagaev, Andrei; Mizyuk, Artem; Chubarenko, Irina; Khatmullilna, Liliya

    2017-04-01

    Microplastics is a burning issue in the marine pollution science. Its sources, ways of propagation and final destiny pose a lot of questions to the modern oceanographers. Hence, a numerical model is an optimal tool for reconstruction of microplastics pathways and fate. Within the MARBLE project (lamp.ocean.ru), a model of Lagrangian particles transport was developed. It was tested coupled with oceanographic transport fields from the operational oceanography product of Copernicus Marine Monitoring Environment Service. Our model deals with two major types of microplastics such as microfibres and buoyant spheroidal particles. We are currently working to increase the grid resolution by means of the NEMO regional configuration for the south-eastern Baltic Sea. Several expeditions were organised to the three regions of the Baltic Sea (the Gotland, the Bornholm, and the Gdansk basins). Water samples from the surface and different water layers were collected, processed, and analysed by our team. A set of laboratory experiments was specifically designed to establish the settling velocity of particles of various shapes and densities. The analysis in question provided us with the understanding necessary for the model to reproduce the large-scale dynamics of microfibres. In the simulation, particles were spreading from the shore to the deep sea, slowly sinking to the bottom, while decreasing in quantity due to conditional sedimentation. Our model is expected to map out the microplastics life cycle and to account for its distribution patterns under the impact of wind and currents. For this purpose, we have already included the parameterization for the wind drag force applied to a particle. Initial results of numerical experiments seem to indicate the importance of proper implicit parameterization of the particle dynamics at the vertical solid boundary. Our suggested solutions to that problem will be presented at the EGU-2017. The MARBLE project is supported by Russian Science

  1. Upper ocean observations in eastern Caribbean Sea reveal barrier layer within a warm core eddy

    Science.gov (United States)

    Rudzin, J. E.; Shay, L. K.; Jaimes, B.; Brewster, J. K.

    2017-02-01

    Three-dimensional measurements of a large warm core eddy (WCE) and the Caribbean Current are acquired using oceanic profilers deployed during a NOAA research aircraft study in September 2014 in the eastern Caribbean Sea. Measurements of the near-surface atmosphere are also collected to examine air-sea processes over the eddy. These novel measurements showcase temperature and salinity for the eddy and background flow, upper ocean stratification, a residing barrier layer (BL), velocity structure, and water mass characteristics. The eddy's thermal structure is alike that of WCEs in the Gulf of Mexico (GoM) whereas surrounding waters have relatively deeper isotherms compared to its GoM counterparts. Analyses suggest that upper ocean stratification within the study region is due to a BL. These are the first observations of a BL inside a WCE to the best of our knowledge. Reduced shear comparisons suggest that the upper ocean, especially within the WCE, would be more resistant to tropical cyclone (TC) induced mixing than the GoM because of the BL. The eddy is suspected to originate from North Brazil Current rings, given its fresh anomalies relative to climatology and surrounding waters and its trajectory prior to sampling. Atmospheric measurements suggest the WCE is influencing the lower atmosphere along its boundaries. These observations signify that not only does this WCE have deep thermal structure and modulate the near-surface atmosphere but it is unique because it has a BL. The findings and analyses suggest that a similar eddy could potentially influence air-sea processes, such as those during TC passage.

  2. An inverse modeling study of circulation in the Eastern Bering Sea during 2007-2010

    Science.gov (United States)

    Panteleev, Gleb; Yaremchuk, Max; Francis, Oceana; Stabeno, Phyllis J.; Weingartner, T.; Zhang, J.

    2016-06-01

    A two-way nested 4d-variational data assimilation system is implemented in the Eastern Bering Sea (EBS) to investigate changes in circulation and thermodynamic state for a 3.8 year period. Assimilated observations include data from 19 moorings deployed on the shelf and in the Bering Strait, 1705 hydrographic stations occupied during eight surveys, and remotely sensed sea surface temperature and sea surface height (SSH) data. Validation of the presented 4dVar reanalysis against the output of two sequential data-assimilative systems (the Bering Ecosystem Study ice-ocean Modeling and Assimilation System (BESTMAS) and the Arctic Cap Nowcast-Forecast System (ACNFS)) has shown that the product is more consistent with the observed transports in the Bering Strait and in the EBS interior both in terms of their magnitude and time variability. Analysis of the data-optimized solution quantifies a sequence of wind-forced events that resulted in the anomalous heat and freshwater transports through the Bering Strait, including a 28 day long flow reversal that occurred in November 2009 and carried Siberian Coastal Current water down to the Gulf of Anadyr. Lagrangian study of the Arctic-bound Pacific waters indicates the extreme importance of the cross-shelf exchange along the path of the Bering Slope Current and quantifies the spectrum of residence times for the waters entering EBS through Unimak Pass and through Aleutian passages. Residence times in the EBS cold pool are diagnosed to be 2-3 times longer than those in the surrounding waters.

  3. Modification of the deep salinity-maximum in the Southern Ocean by circulation in the Antarctic Circumpolar Current and the Weddell Gyre

    Science.gov (United States)

    Donnelly, Matthew; Leach, Harry; Strass, Volker

    2017-07-01

    The evolution of the deep salinity-maximum associated with the Lower Circumpolar Deep Water (LCDW) is assessed using a set of 37 hydrographic sections collected over a 20-year period in the Southern Ocean as part of the WOCE/CLIVAR programme. A circumpolar decrease in the value of the salinity-maximum is observed eastwards from the North Atlantic Deep Water (NADW) in the Atlantic sector of the Southern Ocean through the Indian and Pacific sectors to Drake Passage. Isopycnal mixing processes are limited by circumpolar fronts, and in the Atlantic sector, this acts to limit the direct poleward propagation of the salinity signal. Limited entrainment occurs into the Weddell Gyre, with LCDW entering primarily through the eddy-dominated eastern limb. A vertical mixing coefficient, κV of (2.86 ± 1.06) × 10-4 m2 s-1 and an isopycnal mixing coefficient, κI of (8.97 ± 1.67) × 102 m2 s-1 are calculated for the eastern Indian and Pacific sectors of the Antarctic Circumpolar Current (ACC). A κV of (2.39 ± 2.83) × 10-5 m2 s-1, an order of magnitude smaller, and a κI of (2.47 ± 0.63) × 102 m2 s-1, three times smaller, are calculated for the southern and eastern Weddell Gyre reflecting a more turbulent regime in the ACC and a less turbulent regime in the Weddell Gyre. In agreement with other studies, we conclude that the ACC acts as a barrier to direct meridional transport and mixing in the Atlantic sector evidenced by the eastward propagation of the deep salinity-maximum signal, insulating the Weddell Gyre from short-term changes in NADW characteristics.

  4. The impact of surface currents and sea level on the wave field evolution during St. Jude storm in the eastern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Marili Viitak

    2016-07-01

    Full Text Available A third generation numerical wave model SWAN (Simulating WAves Nearshore was applied to study the spatio-temporal effect of surface currents and sea level height on significant wave height; and to describe the mechanisms responsible for wave–current interaction in the eastern Baltic Sea. Simulation results were validated by comparison with in situ wave measurements in deep and shallow water, carried out using the directional wave buoy and RDCP respectively, and with TerraSAR-X imagery. A hindcast period from 23 to 31 October 2013 included both a period of calm to moderate weather conditions and a severe North-European windstorm called St. Jude. The prevailing wind directions were southerly to westerly. Four simulations with SWAN were made: a control run with dynamical forcing by wind only; and simulations with additional inputs of surface currents and sea level, both separately and combined. A clear effect of surface currents and sea level on the wave field evolution was found. It manifested itself as an increase or decrease of significant wave height of up to 20%. The strength of the interaction was influenced by the propagation directions of waves and surface currents and the severity of weather conditions. An increase in the wave height was mostly seen in shallower waters and in areas where waves and surface currents were propagating in opposite directions. In deeper parts of the eastern Baltic Sea and in case of waves and surface currents propagating in the same direction a decrease occurred.

  5. Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing

    Science.gov (United States)

    Ulrich, Clara; Hemmer-Hansen, Jakob; Boje, Jesper; Christensen, Asbjørn; Hüssy, Karin; Sun, Hailu; Clausen, Lotte Worsøe

    2017-02-01

    A multi-disciplinary study was conducted to clarify stock identity and connectivity patterns in the populations of European plaice (Pleuronectes platessa) in the Skagerrak-Kattegat transition area between the Eastern North Sea and the Baltic Sea. Five independent biological studies were carried out in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing. Hydrogeographical drift modelling suggested that some North Sea juveniles could settle along the coast line of the Skagerrak and the Kattegat. Tagging data suggested that both juveniles and adult fish from the North Sea perform feeding migrations into Skagerrak in summer/autumn. Finally, survey data suggested that Skagerrak also belongs to the area distribution of North Sea plaice. The outcomes of the individual studies were then combined into an overall synthesis. The existence of some resident components was evidenced, but it was also demonstrated that North Sea plaice migrate for feeding into Skagerrak and might constitute a large share of the catches in this area. The mixing of different populations within a management area has implications for stock assessment and management. Choice must be made to either lump or split the populations, and the feasibility and constraints of both options are discussed. The outcomes of this work have directly influenced the management decisions in 2015.

  6. Tectonostratigraphy of the Southern Part of Papua and Arafura Sea, Eastern Indonesia

    Directory of Open Access Journals (Sweden)

    Bhakti H. Harahap

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i3.145Sedimentary history and stratigraphy of the Papua and Arafura Sea areas, eastern Indonesia, are gained from surface geological mapping combined with published data from oil companies. Development of some sedimentary units demonstrates that the tectonism have influenced sedimentation of such units comprising a succession of Phanerozoic rocks developing in a stable continental margin. The succession underlain by Cambrian-Silurian-Devonian metamorphic rocks consists of Tuaba, Kariem, Awitagoh, and Kemum Formation, and Modio Dolomite (Pre-Rift Phase. These rocks having been intruded by Late Permian-Middle Triassic granitoids and Carboniferous granite, are unconformably overlain by Late Carboniferous to Cretaceous siliciclastic-rich units comprising Aifam Group and Tipuma Formation (syn-Rift Phase and Kembelangan Group (Mesozoic Passive Margin Post-Rift. The Aifam Group is separated by a regionally continuous boundary on its top contact from the Triassic-Early Jurassic Tipuma Formation, which filled the block-faulted rift valley subbasins of continentally deposited red beds in the breakup stage. Regionally, developed erosion surfaces of the breakup unconformity have separated these red beds from generally transgressive post-breakup deposits of the Jurassic to Cretaceous marine sediments of the Kembelangan Group. Beach to shallow marine-glauconitic sandstone and shale of the group pass upward into shelf mudstone. Relative sea level fall related to the tectonic stability of the area led to the development of Eocene to Late Miocene platform carbonates of the New Guinea Limestone Supergroup which occurred in the entire island of Papua and the southern of Arafura that overlie these non-carbonate units (Tertiary passive margin. It is separated from the siliciclastic-rich packages by the Tertiary - Pre-Tertiary boundary. The sea level fluctuation within the group was also recorded during the formation of thin, discontinuous

  7. Direct observation of increasing CO 2 in the Weddell Gyre along the Prime Meridian during 1973-2008

    Science.gov (United States)

    van Heuven, Steven M. A. C.; Hoppema, Mario; Huhn, Oliver; Slagter, Hans A.; de Baar, Hein J. W.

    2011-12-01

    The World Ocean takes up a large portion of the anthropogenic CO 2 emitted into the atmosphere. Determining the resulting increase in dissolved inorganic carbon ( CT, expressed in μmol kg -1) is challenging, particularly in the sub-surface and deep Southern Ocean where the time rate of change of CT (in μmol kg -1 decade -1) is commonly expected to be low. We present a determination of this time trend of CT in a dataset of measurements that spans 35 years comprising 10 cruises in the 1973-2008 period along the 0°-meridian in the Weddell Gyre. The inclusion of many cruises aims to generate results that are more robust than may be obtained by taking the difference between only one pair of cruises, each of which may suffer from errors in accuracy. To further improve consistency between cruises, data were adjusted in order to obtain time-invariant values of CT (and other relevant parameters) over the 35 years in the least ventilated local water body, this comprising the deeper Warm Deep Water (WDW) and upper Weddell Sea Deep Water (WSDW). It is assumed that this normalization procedure will allow trends in CT in the more intensely ventilated water masses to be more clearly observed. Time trends were determined directly in measurements of CT, and alternatively in back-calculated values of preformed CT ( CT0; i.e., the CT of the water at the time that it lost contact with the atmosphere). The determined time trends may be attributed to a combination of natural variability (in hydrography or biogeochemistry) and increased uptake of anthropogenic CO 2 from the atmosphere. In order to separate these natural and anthropogenic components, an analysis of the residuals of a multivariate linear regression (MLR), involving the complete time series of all 10 cruises, was additionally performed. This approach is referred to as the Time Series Residuals (TSR) approach. Using the direct method, the time trends of CT in the WSDW are quite small and non-significant at +0.176±0.321

  8. Last Interglacial (Eemian) hydrographic conditions in the south-eastern Baltic Sea, NE Europe, based on dinoflagellates and pollen

    DEFF Research Database (Denmark)

    Head, Martin J.; Seidenkrantz, Marit Solveig Louise Schramm; Janczyk-Kopikowa, Zofia

    2005-01-01

    A rich organic-walled dinoflagellate cyst and pollen record from the Licze borehole in northern Poland has been used to reconstruct the hydrographic history of the southeastern Baltic Sea during the Eemian Stage (Last Interglacial) of the Upper Pleistocene. Warm and saline waters (ca. 10–15 psu...... of arctic waters. Warm and saline conditions of 15–20 psu or more, at least twice present levels, persisted throughout the early Eemian. A rise in sea level at Licze appears to correlate with a similar event in eastern Denmark, as both coincide with the increase in Corylus (ca. 750 years....... Increasing fluvial influence suggests shallowing through RPAZ E5. This study is the first to document dinoflagellate cysts from the Eemian of the southeastern Baltic Sea. Most species have not been reported previously from either Eemian or Holocene sediments of the Baltic Sea proper....

  9. Nutrient dynamics in tropical rivers, lagoons, and coastal ecosystems of eastern Hainan Island, South China Sea

    Science.gov (United States)

    Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

    2014-01-01

    Nutrient dynamics based on field observations made along the eastern Hainan Island during the period 2006-2009 were investigated to understand nutrient biogeochemical processes, and to provide an overview of human perturbations of coastal ecosystems in this tropical region. The rivers showed seasonal variations in nutrient concentrations, with enrichment of dissolved inorganic nitrogen and dissolved silicate, and depletion of PO43-. High riverine concentrations of nitrate mainly originated from agricultural fertilizer inputs. The DIN : PO43- ratios ranged from 37 to 1063, suggesting preferential depletion of PO43- relative to nitrogen in rivers. Chemical weathering in the drainage area might explain the high levels of dissolved silicate. Aquaculture ponds contained high concentrations of NH4+ and dissolved organic nitrogen. The particulate phosphorus concentrations in the study area were lower than those reported for estuaries worldwide. The particulate silicate levels in rivers and lagoons were lower than the global average level. Nutrient biogeochemistry in coastal areas was affected by human activities (e.g., aquaculture, agriculture), and by natural phenomena including typhoons. The nutrient concentrations in coastal waters were low because of dispersion of land-derived nutrients in the sea. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes are magnified by estuarine processes (e.g., regeneration, desorption) in estuaries and Laoyehai Lagoon, but not in Xiaohai Lagoon. Riverine and groundwater inputs were the major sources of nutrients to Xiaohai and Laoyehai lagoons, respectively, and riverine inputs and aquaculture effluents were the major sources for the eastern coast of Hainan Island. Nutrient inputs to the coastal ecosystem increased with typhoon-induced runoff of rainwater, elucidating the important influence of typhoons on small tropical rivers.

  10. Tracers confirm downward mixing of Tyrrhenian Sea upper waters associated with the Eastern Mediterranean Transient

    Directory of Open Access Journals (Sweden)

    W. Roether

    2011-01-01

    Full Text Available Observations of tritium and 3He in the Tyrrhenian Sea, 1987–2009, confirm the enhanced vertical mixing of intermediate waters into the deep waters that has been noted and associated with the Eastern Mediterranean Transient in previous studies. Our evidence for the mixing rests on increasing tracer concentrations in the Tyrrhenian deep waters, accompanied by decreases in the upper waters, which are supplied from the Eastern Mediterranean. The downward transfer is particularly evident between 1987 and 1997. Later on, information partly rests on increasing tritium-3He ages; here we correct the observed 3He for contributions released from the ocean floor. The Tyrrhenian tracer distributions are fully compatible with data upstream of the Sicily Strait and in the Western Mediterranean. The tracer data show that mixing reached to the bottom and confirm a cyclonic nature of the deep water circulation in the Tyrrhenian. They furthermore indicate that horizontal homogenization of the deep waters occurs on a time scale of roughly 5 years. Various features point to a reduced impact of Western Mediterranean Deep Water (WMDW in the Tyrrhenian during the enhanced-mixing period. This is an important finding because it implies less upward mixing of WMDW, which has been named a major process to enable the WMDW to leave the Mediterranean via the Gibraltar Strait. On the other hand, the TDW outflow for several years represented a major influx of enhanced salinity and density waters into the deep-water range of the Western Mediterranean.

  11. Geological and geomechanical properties of the carbonate rocks at the eastern Black Sea Region (NE Turkey)

    Science.gov (United States)

    Ersoy, Hakan; Yalçinalp, Bülent; Arslan, Mehmet; Babacan, Ali Erden; Çetiner, Gözde

    2016-11-01

    Turkey located in the Alpine-Himalayan Mountain Belt has 35% of the natural stone reserves of the world and has good quality marble, limestone, travertine and onyx reserves especially in the western regions of the country. The eastern Black Sea Region with a 1.4 million meters cubes reserve has a little role on the natural stone production in the country. For this reason, this paper deals with investigation on the potential of carbonate stone in the region and determination of the geological and geo-mechanical properties of these rocks in order to provide economic contribution to the national economy. While the study sites are selected among the all carbonate rock sites, the importance as well as the representative of the sites were carefully considered for the region. After representative samples were analyzed for major oxide and trace element compositions to find out petrochemical variations, the experimental program conducted on rock samples for determination of both physical and strength properties of the carbonate rocks. The results of the tests showed that there are significant variations in the geo-mechanical properties of the studied rock groups. The density values vary from 2.48 to 2.70 gr/cm3, water absorption by weight values range from 0.07 to 1.15% and the apparent porosity of the carbonate rocks are between 0.19 and 3.29%. However, the values of the UCS shows variation from 36 to 80 MPa. Tensile and bending strength values range from 3.2 to 7.5 MPa and 6.0-9.2 MPa respectively. Although the onyx samples have the lowest values of apparent porosity and water absorption by weight, these samples do not have the highest values of UCS values owing to occurrence of the micro-cracks. The UCS values of the rock samples were also found after cycling tests However, the limestone samples have less than 5% deterioration after freezing-thawing and wetting-drying tests, but travertine and onyx samples have more than 15% deterioration. Exception of the apparent

  12. Evidence of methane venting and geochemistry of brines on mud volcanoes of the eastern Mediterranean Sea

    Science.gov (United States)

    Charlou, J. L.; Donval, J. P.; Zitter, T.; Roy, N.; Jean-Baptiste, P.; Foucher, J. P.; Woodside, J.; Medinaut Scientific Party

    2003-08-01

    As a part of the Dutch-French MEDINAUT diving expedition in 1998, cold seeps and mud volcanoes were studied and sampled in two distinctive tectonic settings in the eastern Mediterranean Sea. The first setting was the Olimpi Mud Volcano field (OMV area), including Napoli, Milano, Maidstone and Moscow mud volcanoes, south of Crete on the Mediterranean ridge. The second setting was the Anaximander Mountains (AM area), southwestern Turkey, where Amsterdam, Kazan and Kula mud volcanoes were explored. Large methane concentrations (45-892 nmol/kg) were measured in the water column not only above mud volcanoes but also in seeps and vents along related fault systems, indicating intense degassing related to fluid circulation in sediments. The tracer results show that there is considerable variability in terms of gas seepage and matter flux between these mud volcanoes. Brine accumulations found as shallow pools on Napoli or associated with deep faults (Nadir Lake) outside mud volcanoes exhibit variable chlorinity, mineral and gas composition. The brines are significantly enriched in δ18O relative to ambient seawater and are consistent with evaporated seawater. In the Nadir Brine Lake, the level of methane is as high as 5.93 mmol/kg, lower than the methane saturation level of 120 mmol/kg theoretically found at the salinity (120), pressure (200 bar), and temperature (13.6°C) conditions of Nadir lake. In contrast, the shallow brine pools on Napoli mud volcano (also OMV area) have methane levels of only 4.45 μmol/kg. In all brines, helium data show a clear radiogenic isotopic ratio ( R=0.06× Ra), in excellent agreement with recently published data for the Urania basin. Methane to ethane ratios (>1000) and δ13C(CH 4) values (-65.6‰PDB) indicate that the CH 4 is microbially produced. Unlike mid-ocean ridges, where abiogenic methane and helium have a common origin in the brines, the large variation in the CH 4/He ratio indicates that CH 4 and helium sources are unrelated, a

  13. High-resolution Holocene paleoclimatic events from the Southern-eastern Tyrrhenian Sea (Salerno Gulf)

    Science.gov (United States)

    Lirer, F.; Sprovieri, M.; Ferraro, L.; Vallefuoco, M.; Cascella, A.; Pelosi, N.; Capotondi, L.

    2012-12-01

    A high-resolution paleoclimatic study is here presented for the Holocene in the southern-eastern Tyrrhenian Sea, based on calcareous plankton taxa (planktonic foraminifera and calcareous nannofossils) distribution, δ18OG.ruber record, tephrostratigraphy and various dating methods (210Pb and 137Cs, AMS 14C) for a composite sediment core (from the top to the bottom, C90_1m, C90 and C836, water depth 103 mbsl) from the continental shelf of the Salerno Gulf. High sedimentation rates of ca. 1cm/100 yr (base Holocene) to ca 20cm/100 yr (present day), make this area an ideal marine archive of millennial/secular paleoclimate changes. In the early Holocene the study marine sedimentary archive recorded the climatic phases (S1a, S1i and S1b) associated to the deposition of the anoxic event Sapropel S1 in the eastern Mediterranean Sea (4.7 kyr long). In particular, the cold global event reported at 8.2 ka BP by Rohling and Pälike (2005), correlable to the Sapropel S1 interruption (S1i), in here recorded by strong increase in abundances of planktonic foraminifera N. pachyderma right coiled and of calcareous nannofossils B. bigelowii. This event is strongly supported by positive δ18O G.ruber excursion (~0.6 ‰). Upwards to ca 2000 yrs BP (Eneolithic to Golden age), δ18O G.ruber signal combined with calcareous plankton data suggest the occurrence of three Rapid Climatic Chance (RCC), superimposed to short-tern oscillations, those correspond to main changes in geochemical and biological proxies. During the last 2000 yrs BP (Roman period to present day), the planktonic foraminifera show two main turnovers in abundance: from herbivore-opportunistic species to carnivore species at ca 79AD and a progressive turnover between carnivore species and herbivore-opportunistic species at 1462 AD (Medieval Warm Period-Little Ice Age transition). Finally, the onset of a new important cool climatic phase (between 1462 AD and 1940 AD), the so-called Little Ice Age (LIA), expressed in the

  14. The Inaugural SHALDRIL Expedition to the Weddell Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    S. W. Wise,

    2005-09-01

    Full Text Available Introduction In 1994, a group of scientists began discussing a number of important scientific questions that could be addressed by drilling a series of short cores on the Antarctic continental shelf. The group adopted the name SHALDRIL, for SHALlow DRILling, and soon learned that the technology for high-quality sampling of the upper few hundred metersof the stratigraphic column was still lacking.After more than a decade of discussion and several years of detailed planning, SHALDRIL sailed from Punta Arenas, Chile, in March 2005. The objectives of this first SHALDRIL cruise are to demonstrate the feasibility of drilling from an icebreaker platform into the Antarctic continental shelf and to obtain cores from three different sedimentary sequences that previously have not been sampled.The principal objective of SHALDRIL originally was to monitor technological developments in shallow drilling from conventional icebreaking research vessels. In 2000, the SHALDRIL steering committee learned about new and improved drilling systems that can core through gravelly glacial deposits in water depths of several hundred meters and to subbottom depths of a few hundred meters(SHALDRIL Steering Committee, 2001. These systems can be operated from the icebreaking research vessel Nathaniel B. Palmer (Fig. 1; thus, the long-term project has now entered the next phase of testing this proven drilling technology aboard a U. S. Antarctic Program vessel.

  15. Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

    Directory of Open Access Journals (Sweden)

    Nicholas W Pilfold

    Full Text Available BACKGROUND: Polar bears (Ursus maritimus of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650 and hunting attempts on ringed seal (Pusa hispida lairs (n=1396 observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. PRINCIPAL FINDINGS: Polar bears primarily preyed on ringed seals (90.2% while bearded seals (Erignathus barbatus only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344 of the ringed seals killed, while their pups comprised 38.4% (132/344. Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344 of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121, and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78. The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2 =0.30, P=0.04, but was not correlated with the number of adult kills (P=0.37. CONCLUSIONS/SIGNIFICANCE: Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

  16. Barium, its seasonal variability and its relation to CO2 in the Eastern Beaufort Sea

    Science.gov (United States)

    Thomas, Helmuth; Dehairs, Frank; Shadwick, Elizabeth H.; Navez, Jacques; Gratton, Yves

    2010-05-01

    During the Circumpolar Flow Lead (CFL) study, a Canadian contribution to the International Polar Year (IPY), the icebreaker CCGS Amundsen over wintered in the Eastern Beaufort Sea. This facilitated year-round observations of hydrochemical water column properties during both ice-free and ice-covered seasons from summer 2007 until summer 2008, as well as an east-west section through the Canadian Arctic Archipelago from the west coast of Greenland into the Beaufort Sea. In the present study we investigate the seasonal and spatial variability of Barium (Ba), which is often used to discriminate terrestrial fresh water from ice melt. We sampled for Ba approximately every two weeks throughout the year, including several nearshore stations during the ice-free seasons. In parallel we sampled for dissolved inorganic carbon (DIC) and Alkalinity (AT), stable oxygen isotopes in seawater (delta18O), as well as standard hydrochemical properties. Ba reveals to a large degree nutrient-type behavior with surface concentrations of approximately 60nM. The subsurface maximum (approx. 80nM) is located between 70m and 100m, at the boundary between the Polar Mixed Layer and the underlying watermass of Pacific origin. Deep water concentrations range between 40nM and 50nM. Only samples taken near the mouth of rivers reveal significantly higher Ba concentrations. Ba reveals a linear relationship to DIC, if the latter one is normalized to a standard salinity. We shall discuss the seasonal evolution and spatial distribution of Ba, also in relation to DIC and AT, and delta18O.

  17. Expelled subsalt fluids form a pockmark field in the eastern Red Sea

    Science.gov (United States)

    Feldens, P.; Schmidt, M.; Mücke, I.; Augustin, N.; Al-Farawati, R.; Orif, M.; Faber, E.

    2016-10-01

    This study aimed to constrain the source area of fluids responsible for the formation of a pockmark field in the eastern Red Sea. The newly discovered field extends over an area of at least 1,000 km2 at a water depth of ~400 m. The pockmarks have modal diameters of 140-150 m and are either randomly distributed on the seafloor or aligned within valleys approximately 25 m deep and several kilometres in length. Seismic data show that chimneys and/or regions of acoustic turbidity prevail beneath the pockmark field down to the top of Miocene evaporites, which are widespread in the Red Sea. Four gravity cores were taken from the pockmark field. For most of the cores, geochemical analyses show that porewater has a higher Cl concentration than the local seawater and increased Cl/Br ratios, which indicate an origin from evaporites. The adsorbed hydrocarbons are of thermal origin, with C1/(C2+C3) ratios between 4 and 23 and stable carbon isotope data for methane varying from δ13C of -34 to -36.4‰ with respect to Vienna Pee Dee Belemnite. On the basis of the calculated maturity of the source rock of 1.2-1.4 Ro, local thermal gradients and sedimentation rates, its deeper depth boundary is approximated at 2,000 to 2,200 m. The results indicate that the adsorbed hydrocarbons sampled at the seafloor had to pass through an evaporite sequence of potentially several hundred metres to a few km in thickness. The most likely explanation for the increased permeability of the evaporite sequence is brittle deformation triggered by extensive local tectonic movements and supported by high fluid overpressure within the evaporite sequence.

  18. Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

    Science.gov (United States)

    Lampadariou, N.; Kalogeropoulou, V.; Sevastou, K.; Keklikoglou, K.; Sarrazin, J.

    2013-08-01

    Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems) cruise (2007) with the remotely operated vehicle (ROV) Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field); and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

  19. Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    N. Lampadariou

    2013-08-01

    Full Text Available Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems cruise (2007 with the remotely operated vehicle (ROV Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field; and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field. The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

  20. The diet and feeding ecology of Conger conger (L. 1758 in the deep waters of the Eastern Ionian Sea

    Directory of Open Access Journals (Sweden)

    A. ANASTASOPOULOU

    2013-06-01

    Full Text Available The diet of the European conger eel Conger conger was investigated for the first time in the Eastern Mediterranean. Fish dominated the European conger eel diet in the deep waters of E. Ionian Sea. All other prey taxa were identified as accidental preys. However, intestine analysis showed that Natantia, Brachyura and Cephalopoda might have a more important contribution in the diet of the species. C. conger exhibited a benthopelagic feeding behavior as it preyed upon both demersal and mesopelagic taxa. The high vacuity index and the low stomach and intestine fullness indicated that the feeding intensity of the species in the deep waters of Eastern Ionian Sea was quite low. C. conger feeding strategy was characterised by specialisation in various resource items. A between-phenotype contribution to niche width was observed for some prey categories. European Conger eel feeding specialisation seemed to be an adaptation to a food-scarce environment, as typified in deep-water habitats

  1. AFSC/RACE/FBEP/Hurst: Distributional patterns of 0-group Pacific cod (Gadus macrocephalus) in the eastern Bering Sea under variable recruitment and thermal conditions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study that analyzed the late summer distribution of juvenile Pacific cod in the eastern Bering Sea for 6 cohorts (2004-2009), based on catches...

  2. AFSC/RACE/EcoFOCI: Chlorophyll: variability in spring chlorophyll concentrations and zooplankotn on the eastern Bering Sea shelf - cruise Healy 07-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were collected under NSF Grant # ARC-0722448 ("BEST: Impacts of Sea-ice on the Hydrographic Structure, Nutrients, and Mesozooplankton over the Eastern...

  3. Chemical oceanography of the Arabian Sea: Part III - Studies on nutrient fraction and stoichiometric relationship in the Northern and the Eastern Basins

    Digital Repository Service at National Institute of Oceanography (India)

    SenGupta, R.; Sankaranarayanan, V.N.; De; Fondekar, S.P.

    Phosphorus and inorganic nitrogen compounds have been divided into 'reserved' andoxidative fractions based on their relationships with apparent oxygen utilization in the northern and the north-eastern basins of the Arabian Sea.Two oxygen minima...

  4. 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...

  5. Glacial to interglacial contrast in the calcium carbonate content and influence of Indus discharge in two eastern Arabian sea cores

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    , Palaeoecology, 86 (1991): 255-263 255 Elsevier Science Publishers B.V., Amsterdam Glacial to interglacial contrasts in the calcium carbonate content and influence of Indus discharge in two eastern Arabian Sea cores P. Divakar Naidu National Institute... of Oceanography, DonaPaula, Goa 403004, India (Received January 2, 1990; revised version accepted January 18, 1991) ABSTRACT Divakar Naidu, P., 1991. Glacial to interglacial contrasts in the calcium carbonate content and influence of Indus discharge in two...

  6. Methodology for filling gaps and forecast in sea level: Applications to the eastern English Channel and the North Atlantic Sea (western France)

    Science.gov (United States)

    Turki, Imen; Laignel, Benoit; Kakeh, Nabil; Chevalier, Laetitia; Costa, Stephane

    2014-05-01

    This research was carried out in the framework of the program Surface Water and Ocean Topography (SWOT) which is a partnership between NASA and CNES. Sea level is a key variable in marine, climate, and coastal process studies. In this research, a new methodology was implemented for filling gaps and forecasting the sea level by combining classical harmonic models to high statistical methods. In agreement with previous studies, this work indicates that sea level heights are correlated to climate conditions of sea level pressures (SLP). After averaging out surface waves from the mean sea level, the deterministic tides and the stochastic processes of residual surges were investigated using classical harmonic analyses and a statistical model of autoregressive moving average (ARMA), respectively. The estimation of the residual surges was also investigated together with the SLP. This new methodology was applied to the Atlantic sea and the eastern English Channel (western France). Results have shown that the developed model reproduces the observations with RMSE of 4.5 cm and 7 cm for 12 days and 30 days of gaps, respectively. For medium scales of 6 months, the RMSE reaches 9,2 cm. Larger scales more than 10 months were also statistically reproduced. Accordingly, the proposed model seems to be more promising for filling gaps and estimating the sea level at short- to large- time scales. This new methodology presents a coherent, simple, and easy tool to estimate the deterministic nature of tidal processes and the stochastic framework of residual surges. Key words: sea level forecast, astronomical tides, residual surges, ARMA, sea level pressure.

  7. Buried paleo-sedimentary basins in the north-eastern Black Sea-Azov Sea area and tectonic implications (DOBRE-2)

    Science.gov (United States)

    Starostenko, Vitaly; Stephenson, Randell; Janik, Tomasz; Tolkunov, Anatoly

    2014-05-01

    A number of independent but inter-related projects carried out under the auspices of various national and international programmes in Ukraine including DARIUS were aimed at imaging the upper lithosphere, crustal and sedimentary basin architecture in the north-eastern Black Sea, southern Crimea and Kerch peninsulas and the Azov Sea. This region marks the transition from relatively undisturbed Precambrian European cratonic crust and lithosphere north of the Azov Sea to areas of significant Phanerozoic tectonics and basin development, in both extensional as well as compressional environments, to the south, including the eastern Black Sea rift, which is the main sedimentary basin of the study area. The wide-angle reflection and refraction (WARR) profile DOBRE-2, a Ukrainian national project with international participation (see below), overlapping some 115 km of the southern end of the DOBREfraction'99 profile (that crosses the intracratonic Donbas Foldbelt) in the north and running to the eastern Black Sea basin in the south, utilised on- and offshore recording and energy sources. It maps crustal velocity structure across the craton margin and documents, among other things, that the Moho deepens from 40 km to ~47 km to the southwest below the Azov Sea and Crimean-Caucasus deformed zone. A regional CDP seismic profile coincident with DOBRE-2, crossing the Azov Sea, Kerch Peninsula and the north-eastern Black Sea southwest to the Ukraine-Turkey border, acquired by Ukrgeofisika (the Ukrainian national geophysical company) reveals in its inferred structural relationships the ages of Cretaceous and younger extensional and subsequent basin inversion tectonic events as well as the 2D geometry of basement displacement associated with post mid-Eocene inversion. A direct comparison of the results of the WARR velocity model and the near-vertical reflection structural image has been made by converting the former into the time domain. The results dramatically demonstrate that

  8. Characteristics of benthos of the North-eastern Caspian Sea, technology of its recovery and impact of the oil and gas extraction on the environment

    Directory of Open Access Journals (Sweden)

    G. M. Abdurahmanov

    2009-01-01

    Full Text Available In the article is in details considered the technology of investigation and an oil recovery in the eastern part of Northern Caspian Sea. It is shown that the most negative influence will test the benthos of the water area. Materials on structure, seasonal dynamics and biomass of groundorganisms of eastern part of the Northern Caspian Sea are resulted.

  9. Comparative study of organohalogen contamination between two populations of Eastern Atlantic loggerhead sea turtles (Caretta caretta).

    Science.gov (United States)

    Camacho, María; Boada, Luis D; Orós, Jorge; López, Pedro; Zumbado, Manuel; Almeida-González, Maira; Luzardo, Octavio P

    2013-12-01

    We evaluated the presence of 37 organohalogen contaminants in plasma samples from 162 juvenile and 197 adult loggerhead turtles (Caretta caretta) from the archipelagos of the Canary Islands and Cape Verde, respectively, and compared the contamination profiles found. We detected five organochlorine pesticides (OCP) and 16 polychlorinated biphenyls (PCBs). The concentrations of the two groups of contaminants were higher in turtles from the Canary Islands (OCPs, 1.04 vs. 0.37 ng/mL; PCBs, 1.92 vs. 0.08 ng/mL). We also observed a different profile of PCB contamination between the two populations. In addition, there was a negative correlation between body size and the total concentration of PCBs in the Canary Islands turtles, but not in turtles from Cape Verde. The present study presents the first data on the organochlorine contaminants (OCs) of live turtles from Canary Islands. In addition, we perform a comparison of the levels and profiles of OCs between these two different groups of loggerhead sea turtles from the Eastern Atlantic.

  10. Seaweed assemblage changes in the eastern Cantabrian Sea and their potential relationship to climate change

    Science.gov (United States)

    Díez, I.; Muguerza, N.; Santolaria, A.; Ganzedo, U.; Gorostiaga, J. M.

    2012-03-01

    Rising sea-surface temperatures (SSTs) over the last three decades in the south-eastern part of the Bay of Biscay could be affecting phytobenthic assemblage distributions. This study assesses recent changes in species abundance and diversity along the western Basque coast by studying 18 locations in summer 1991 and in 2008. There were substantial changes in the structure of subtidal vegetation between the two surveys: 1) an increase in coralline algae; 2) changes in the distribution patterns of the canopy species; 3) disappearance of kelps; 4) increases in warm-water species, mainly morphologically simple forms; 5) introduction and expansion of non-indigenous species, and 6) increases in species richness and diversity. These results are consistent with the rise detected in SST, particularly in summer when SST was found to have risen by as much as 1 °C from 1980 to 2008. Furthermore, two extreme warming events occurred in the summers of 2003 and 2006. However, some biological shifts cannot be explained by warmer waters alone. Only limited data are available on changes in nutrient concentrations and water transparency, but these factors are also thought to be involved in the biological changes detected.

  11. Relationship of spontaneous pneumothorax cases seen in Eastern Black Sea region with meteorological changes

    Science.gov (United States)

    Yamac, Mustafa Esat; Karapolat, Sami; Turkyilmaz, Atila; Seyis, Kubra Nur; Tekinbas, Celal

    2017-08-01

    The relationship of climate changes or weather conditions with the incidence of pneumothorax has been explored for many years. We aimed at revealing the effects of meteorological changes on the incidence of pneumothorax in the Eastern Black Sea region where spontaneous pneumothorax cases are seen relatively more frequently. The records of 195 subjects (179 males and 16 females) who had been monitored and treated due to spontaneous pneumothorax between January 2006 and December 2012 at our clinic were reviewed retrospectively, and their relationship was investigated with the meteorological data obtained by going through the database archive records of the 11th Regional Meteorology Directorate for the years between 2006 and 2012. Wind velocity was observed to be less in the days of having spontaneous pneumothorax than in the days of having no spontaneous pneumothorax, and the difference was found statistically significant ( P = 0.026). The people of our region whose active lifestyle is reflected in their working life, social life, and even in their folk dances usually take a rest in the days of slower wind speed. We think that this state of resting leads to an increase in the frequency of spontaneous pneumothorax.

  12. Assessment of big floods in the Eastern Black Sea Basin of Turkey.

    Science.gov (United States)

    Yüksek, Ömer; Kankal, Murat; Üçüncü, Osman

    2013-01-01

    In this study, general knowledge and some details of the floods in Eastern Black Sea Basin of Turkey are presented. Brief hydro-meteorological analysis of selected nine floods and detailed analysis of the greatest flood are given. In the studied area, 51 big floods have taken place between 1955-2005 years, causing 258 deaths and nearly US $500,000,000 of damage. Most of the floods have occurred in June, July and August. It is concluded that especially for the rainstorms that have caused significantly damages, the return periods of the rainfall heights and resultant flood discharges have gone up to 250 and 500 years, respectively. A general agreement is observed between the return periods of rains and resultant floods. It is concluded that there has been no significant climate change to cause increases in flood harms. The most important human factors to increase the damage are determined as wrong and illegal land use, deforestation and wrong urbanization and settlement, psychological and technical factors. Some structural and non-structural measures to mitigate flood damages are also included in the paper. Structural measures include dykes and flood levees. Main non-structural measures include flood warning system, modification of land use, watershed management and improvement, flood insurance, organization of flood management studies, coordination between related institutions and education of the people and informing of the stakeholders.

  13. Determination of regional screening criteria for retinopathy ofprematurity in the Eastern Black Sea region of Turkey.

    Science.gov (United States)

    Kola, Mehmet; Hacioğlu, Dilek; Erdöl, Hidayet; Türk, Adem; Aslan, Yakup

    2016-02-17

    To establish a regional screening protocol for retinopathy of prematurity (ROP). Data were analyzed from the hospital records of 1241 infants with gestational age (GA) at birth ≤36 weeks and birth weight (BW) of ≤3600 g. The mean GA of the infants was 32.05 ± 2.7 weeks and the mean BW was 1780.5 ± 576 g. ROP at any stage was detected in 703 of the 1241 infants (555 female). Eleven infants with type 1 ROP were treated with 810 nm diode laser photocoagulation. No treatment was needed in infants born after 33 weeks of gestation and weighing over 1760 g. Logistic regression analysis showed a significant relationship between the development of ROP and GA, BW, number of deliveries, respiratory distress syndrome, and treatment with oxygen or mechanical ventilation. Receiver operating characteristic curve analysis showed that a GA of 33 weeks or a BW of 1770 g appears to be an appropriate criterion for identifying infants who may require ROP treatment. GA ≤ 33 weeks and BW ≤ 1770 g can be used as screening criteria in terms of ROP in infants for the Eastern Black Sea region.

  14. Chelidoperca stella, a new species of perchlet (Perciformes: Serranidae) from the Andaman Sea, eastern Indian Ocean.

    Science.gov (United States)

    Matsunuma, Mizuki; Motomura, Hiroyuki

    2016-03-16

    A new species of serranid fish, Chelidoperca stella, is described on the basis of five specimens from the Andaman Sea in the eastern Indian Ocean. The species can be readily distinguished from all valid congeners by having fewer pored lateral-line scales (34 or 35 vs. 40-45 in the latter) and the pelvic fin white with several small yellow spots (vs. spots absent). The species is also characterized by having relatively high counts of small serrae on the posterior margins of the preopercle (33-43 serrae), interopercle (7-10) and subopercle (18-28), despite the small body size (51.7-61.8 mm SL). Although Chelidoperca stella resembles C. margaritifera in having 2.5 scale rows between lateral line and the sixth dorsal-fin spine base, a relatively wider interorbital region, and the interorbital scales not reaching a vertical through the orbit anterior margin, but differs by having the above-mentioned diagnostic characters plus a slightly shorter longest anal-fin soft ray [17.4-18.7 (mean 18.1) % SL vs. 22.6-26.4 (24.4) % SL in C. margaritifera].

  15. Biosynthetic potential of actinomycetes in brown forest soil on the eastern coast of the aegean sea

    Science.gov (United States)

    Shirokikh, I. G.; Shirokikh, A. A.

    2017-11-01

    The taxonomic and functional structures of the actinomycetal complex in the litter and upper horizon of the brown forest soil was studied in a Pinus brutia var. pendulifolia forest on the eastern coast of the Aegean Sea. The complex of actinomycetes included representatives of the Streptomyces and Micromonospora genera and oligosporus forms. Streptomycetes predominated (73.8%) in the soil, and micromonospores (66.7%) were dominants in the litter. Thirty isolates of ten Streptomyces species from five series and three sections prevailed. In the upper soil horizon, species of the Helvolo-Flavus Helvolus section predominated (48%); the S. felleus species occurred most frequently. Among the isolated cultures, the S. globisporus and S. sindenensis species capable to produce antitumor antibiotics were found. The testing of the antimicrobial activity of the natural isolates showed that five strains inhibit the growth of pathogenic Fusarium sp., Alternaria sp., Acremonium sp., and Bipolaris sorokiniana fungi. When testing the effect of streptomycetes on the production of cellulases, a high-efficient strain belonging to the S. noboritoensis species was revealed. All the streptomycetes isolated from the brown forest soil produced auxins at the rate of 7.8 to 19.7 μg of indole acetic acid/mL of the liquid medium in the presence of 200 mg/L of tryptophan. Twelve isolates of streptomycetes were transferred to the collection of biotechnologically promising cultures for studying their properties.

  16. Movement Ecology of the Reef Manta Ray Manta alfredi in the Eastern Red Sea

    KAUST Repository

    Braun, Camrin D.

    2013-07-01

    Many well-studied elasmobranch populations have recently exhibited significant decline. The limited data related to fisheries and sightings for many unstudied or poorly understood populations indicate that these are also suffering. Directed fisheries and more cryptic threats such as entanglement and vessel strike represent significant risk to mobulid rays, arguably one of the most vulnerable elasmobranch groups. Very little information currently exists describing the basic ecology of manta rays or quantifying anthropogenic threats and impacts; however, recent efforts have drastically improved the body of knowledge available for these species, including oceanographic influences on movement, seasonal migration, and mating behaviors. Nevertheless, Red Sea mantas remain completely enigmatic. In this thesis, Chapter 1 details results from tagging 18 reef manta rays Manta alfredi in the eastern Red Sea using satellite and acoustic tag technology and demonstrates that mantas occupy areas with high human traffic. The combined satellite and acoustic techniques define both regional movements and ‘hotspots’ of habitat use where there is significant potential for manta-human interaction. I also present opportunistic sighting data that corroborate anthropogenic impacts on this population. Chapter 2 explores the vertical component of the nine satellite tags that were deployed on Manta alfredi as described in the previous chapter. Seven tags returned adequate data for analysis. Three of the seven were physically recovered yielding full archival datasets of depth, temperature, and light levels every 10-15 seconds for over 2.6 5 million cumulative data points. Mantas frequented the upper 10 m during the day and occupied deeper water through nocturnal periods. Individuals also exhibited deep diving behavior as deep as 432 m, extending the known depth range of the species. An investigation of 76 high-resolution deep dives suggests gliding is a significant behavioral component of

  17. Population structure in Atlantic cod in the eastern North Sea-Skagerrak-Kattegat: early life stage dispersal and adult migration.

    Science.gov (United States)

    André, Carl; Svedäng, Henrik; Knutsen, Halvor; Dahle, Geir; Jonsson, Patrik; Ring, Anna-Karin; Sköld, Mattias; Jorde, Per Erik

    2016-02-03

    In marine fish species, where pelagic egg and larvae drift with ocean currents, population structure has been suggested to be maintained by larval retention due to hydrographic structuring and by homing of adult fish to natal areas. Whilst natal homing of adults has been demonstrated for anadromous and coral reef fishes, there are few documented examples of philopatric migration in temperate marine fish species. Here, we demonstrate temporally stable genetic differentiation among spawning populations of Atlantic cod (Gadus morhua L.), and present genetic and behavioural evidence for larval drift and philopatric migration in the eastern North Sea-Skagerrak-Kattegat area. We show that juvenile cod collected in the eastern Skagerrak and central Kattegat are genetically similar to cod from offshore spawning areas in the eastern North Sea. Genetic assignment of individual 2-5 year old fish indicates that cod residing at, or migrating towards, spawning areas in Kattegat and the North Sea display philopatric behaviours. Together these findings suggest a loop between spawning, larval drift and adult return-migrations to spawning areas and underlines that both oceanographic processes and migratory behaviour in the adult phase may be important for stock separation and integrity in marine temperate fishes such as Atlantic cod.

  18. Miocene to recent tectonic and sedimentary evolution of the Anaximander Seamounts; eastern Mediterranean Sea

    Science.gov (United States)

    Cranshaw, Jennifer

    This thesis is focused on the Messinian to Recent tectonic and sedimentary evolution of the Anaximander Mountains and surrounding environs in the eastern Mediterranean Sea. It is based on processing of high-resolution seismic reflection data and the interpretation and mapping of seismic reflection profiles collected from this area during the 2001 and 2007 research cruises. The data show that the greater Anaximander Mountains region experienced a short interval of tectonic quiescence during the Messinian when a thin evaporite unit was deposited across a major erosional surface. This phase of limited tectonic activity ended in the latest Miocene and was replaced by an erosional phase. Major unconformities in the area are interpreted to develop during the desiccation of the eastern Mediterranean associated with the so-called Messinian salinity crisis. During the early Pliocene, the region experienced an increase in tectonic activity, dominated by transpression. Small amounts of growth observed in Pliocene-Quaternary sediments suggested that the tectonic activity remained low during the early Pliocene-Quaternary. However, the extensive growth strata wedges developed in older sediments indicate a period of accelerated tectonic activity during the mid-late Pliocene-Quaternary. This study suggests that the Anaximander Mountain (sensu stricto ) and the Anaximenes Mountain developed during the Pliocene-Quaternary as the result of a crustal-scale thick-skinned linked imbricate thrust fan. The development of back thrusts in both mountains heightened the seafloor morphology of these submarine mountains and brought Eocene-Oligocene sediments into the core of these mountains. The Sim Erinc Plateau represents a 30-40 km wide transpressional fault zone developed during the Pliocene-Quaternary. In this region the corrugated seafloor morphology observed in the multibeam bathymetry map is the reflection of high-angle faults. It is speculated that this transpressional fault zone

  19. Aerosol direct effect on solar radiation over the eastern Mediterranean Sea based on AVHRR satellite measurements

    Science.gov (United States)

    Georgakaki, Paraskevi; Papadimas, Christos D.; Hatzianastassiou, Nikos; Fotiadi, Aggeliki; Matsoukas, Christos; Stackhouse, Paul; Kanakidou, Maria; Vardavas, Ilias M.

    2017-04-01

    Despite the improved scientific understanding of the direct effect of aerosols on solar radiation (direct radiative effect, DRE) improvements are necessary, for example regarding the accuracy of the magnitude of estimated DREs and their spatial and temporal variability. This variability cannot be ensured by in-situ surface and airborne measurements, while it is also relatively difficult to capture through satellite observations. This becomes even more difficult when complete spatial coverage of extended areas is required, especially concerning areas that host various aerosol types with variable physico-chemical and optical aerosol properties. Better assessments of aerosol DREs are necessary, relying on aerosol optical properties with high spatial and temporal variation. The present study aims to provide a refined, along these lines, assessment of aerosol DREs over the eastern Mediterranean (EM) Sea, which is a key area for aerosol studies. Daily DREs are computed for 1˚ x1˚ latitude-longitude grids with the FORTH detailed spectral radiation transfer model (RTM) using input data for various atmospheric and surface parameters, such as clouds, water vapor, ozone and surface albedo, taken from the NASA-Langley Global Earth Observing System (GEOS) database. The model spectral aerosol optical depth (AOD), single scattering albedo and asymmetry parameter are taken from the Global Aerosol Data Set and the NOAA Climate Data Record (CDR) version 2 of Advanced Very High resolution Radiometer (AVHRR) AOD dataset which is available over oceans at 0.63 microns and at 0.1˚ x0.1˚ . The aerosol DREs are computed at the surface, the top-of-atmosphere and within the atmosphere, over the period 1985-1995. Preliminary model results for the period 1990-1993 reveal a significant spatial and temporal variability of DREs over the EM Sea, for example larger values over the Aegean and Black Seas, surrounded by land areas with significant anthropogenic aerosol sources, and over the

  20. A new hybrid model for filling gaps and forecast in sea level: application to the eastern English Channel and the North Atlantic Sea (western France)

    Science.gov (United States)

    Turki, Imen; Laignel, Benoit; Kakeh, Nabil; Chevalier, Laetitia; Costa, Stephane

    2015-04-01

    This research is carried out in the framework of the program Surface Water and Ocean Topography (SWOT) which is a partnership between NASA and CNES. Here, a new hybrid model is implemented for filling gaps and forecasting the hourly sea level variability by combining classical harmonic analyses to high statistical methods to reproduce the deterministic and stochastic processes, respectively. After simulating the mean trend sea level and astronomical tides, the nontidal residual surges are investigated using an autoregressive moving average (ARMA) methods by two ways: (1) applying a purely statistical approach and (2) introducing the SLP in ARMA as a main physical process driving the residual sea level. The new hybrid model is applied to the western Atlantic sea and the eastern English Channel. Using ARMA model and considering the SLP, results show that the hourly sea level observations of gauges with are well reproduced with a root mean square error (RMSE) ranging between 4.5 and 7 cm for 1 to 30 days of gaps and an explained variance more than 80 %. For larger gaps of months, the RMSE reaches 9 cm. The negative and the positive extreme values of sea levels are also well reproduced with a mean explained variance between 70 and 85 %. The statistical behavior of 1-year modeled residual components shows good agreements with observations. The frequency analysis using the discrete wavelet transform illustrate strong correlations between observed and modeled energy spectrum and the bands of variability. Accordingly, the proposed model presents a coherent, simple, and easy tool to estimate the total sea level at timescales from days to months. The ARMA model seems to be more promising for filling gaps and estimating the sea level at larger scales of years by introducing more physical processes driving its stochastic variability.

  1. Currents and transport on the Eastern Bering Sea shelf: An integration of over 20 years of data

    Science.gov (United States)

    Stabeno, P. J.; Danielson, S. L.; Kachel, D. G.; Kachel, N. B.; Mordy, C. W.

    2016-12-01

    More than 20 years of data from moorings, satellite-tracked drifters and hydrographic surveys are integrated to provide a comprehensive view of currents and transport on the eastern Bering Sea shelf. The major sources of water onto the eastern Bering Sea shelf are North Pacific water flowing through Unimak Pass and Bering Slope water flowing onto the shelf usually via the canyons that intersect the shelf break. Absolute geostrophic transport through Unimak Pass varies from an average of 0.25×106 m3 s-1 (Sv) in the warm months to 0.43 Sv in the cold months. Flow along the 50-m isobath is weak, with a transport of Unimak Pass to Bering Strait is >13 months and from Amukta Pass to Bering Strait via the Bering Slope Current is >8 months. Consequently, the source of most of the heat transported into the Arctic through Bering Strait is a result of air-sea interactions local to the northern Bering Sea. Analysis of the currents and water properties on the southern shelf indicates that 50% of the shelf water is exchanged with slope water during October-January each year. This exchange elevates the October mid-shelf average nitrate level from 6 μM to 14-16 μM by the end of January.

  2. Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea

    KAUST Repository

    Tsangaris, Catherine

    2015-09-23

    Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the “Integrated Biological Responses version 2” index was useful for the interpretation of overall biomarker responses.

  3. Estimates of Eastern Equatorial Pacific Sea Surface Temperatures During the Pliocene From Carbonate 'Clumped Isotope' Thermometry

    Science.gov (United States)

    Thiagarajan, N.; Tripati, A.; Eiler, J.

    2007-12-01

    The early Pliocene (5 to 3 Ma) was an interval in Earth history that was globally warmer than the present; thus, study of the details of Pliocene climate can provide insights into the dynamics of warm climates. There are two competing models of the temperature structure of the tropical Pacific upper-ocean during the early Pliocene: the dynamical 'ocean thermostat' model [1,2] and the 'El Padre' (or permanent 'El Nino') model [3], each of which predict zonal temperature gradients and mean conditions in the Eastern Equatorial Pacific (EEP), and which differ markedly from one another in these predictions. The dynamical 'ocean thermostat' model predicts an increased temperature contrast between the Western Equatorial Pacific (WEP) and EEP, enhanced thermocline tilt and intensified upwelling under warmer conditions. In contrast, the 'El Padre' model postulates a collapse of the zonal temperature gradient, reduced thermocline tilt and a reduction in upwelling and/or warmer temperatures of upwelled waters. Existing reconstructions of tropical temperatures produce WEP sea surface temperatures which agree with each other, but yield very different results in the EEP [4,5]. We have reconstructed EEP sea surface temperatures at Ocean Drilling Program (ODP) Site 847 using a few samples spanning key intervals of the last 6 million years using carbonate clumped isotope thermometer [6,7,8]. This technique is based on the temperature dependence of the abundances of 13C-18O bonds in carbonate minerals. Initial measurements of planktonic foraminifera and coccoliths from ODP Site 847 indicate cool EEP sea surface temperatures, supporting models of Pliocene climate that have enhanced zonal temperature gradients, relative to modern. Analyses of Globigerinoides sacculifer (with sac) from sediments indicate calcification temperatures of 20.3°C ± 0.1°C and seawater δ18O values of -0.8‰ ± 0.1‰ from ~6.1 to 5.1 million years ago. Measurements of a mixed coccolith assemblage from the

  4. Menes caldera, a highly active site of brine seepage in the Eastern Mediterranean Sea: "In situ" observations from the NAUTINIL expedition

    NARCIS (Netherlands)

    Huguen, C.; Foucher, J.-P.; Mascle, J.; Ondreas, H.; Thouement, M.; Gontharet, S.; Stadnitskaia, A.; Pierre, C; Bayon, G.; Loncke, L; Boetius, A.; Bouloubassi, I.; de Lange, G.; Caprais, J.-C.; Fouquet, Y.; Woodside, J.M.; Dupre, S.

    2009-01-01

    This paper reports the first "in situ" seafloor observations of fluid escape structures in a fault-controlled caldera-type depression of about 8 km diameter, named the Menes caldera, in the Eastern Mediterranean sea off Egypt (western province of the Nile Deep Sea Fan). A detailed analysis of seven

  5. Red Sea Rift-Related Quseir Basalts, Central Eastern Desert, Egypt: Petrogenetic and Geodynamic Evolution

    Science.gov (United States)

    Farahat, Esam; Ali, Shehata; Hauzenberger, Christoph

    2015-04-01

    Mineral and whole rock chemistry of Tertiary Red Sea rift-related basalts occurred in south Quseir city, Central Eastern Desert, Egypt has been presented to investigate their petrogenetic and geodynamic evolution. The South Quseir basalts (SQB) have been classified as high-Ti tholeiitic lava (TiO2 >2 wt. %) emplaced in anorogenic tectonic setting. Their Mg# varies from 48 to 53. Pearce element ratios (PER) suggest that the SQB magmas have evolved through fractional crystallization of olivine + clinopyroxene ± plagioclase assemblages, however, the absence of Eu-anomaly argues against plagioclase fractionation. The clinopyroxene compositions provide evidence for polybaric fractionation of the parental mafic magma. Estimated temperatures of crystallization range from 1143 to 1323 oC for olivines, 1031 to 1207 oC for clinopyroxenes, 600 to 900 oC for feldspars, and 638 to 787 oC for Fe-Ti oxides. Oxygen fugacity (ƒO2) values range from -15.16 to -19.5. The incompatible trace element signatures of the SQB (La/Ba = 0.08-0.10 and La/Nb = 0.89-1.04) are similar to those of ocean island basalts (OIB) generated from asthenospheric mantle source unaffected by subduction components. Modelling calculations indicate that the SQB primary magmas were derived from 4-5% partial melting of a garnet-bearing lherzolite mantle source which had a potential temperature (Tp= 1334-1432 °C; based on olivine liquid equilibria) corresponding to ambient temperature of MORB (i.e. passive rifting). This ambient mantle would have to rise to shallower depths (< 100 km) in the upper mantle to cross the dry mantle solidus and stimulate adiabatic partial melting. These estimates along with absence of HIMU (high μ refers to high 238U/204Pb) components (based on trace element data) show that the SQB volcanism isn't associated with thermally driven mantle plumes. Thus, the SQB magma generation is related to extensional regime through passive upwelling and adiabatic decompression melting of an

  6. New techniques on oil spill modelling applied in the Eastern Mediterranean sea

    Science.gov (United States)

    Zodiatis, George; Kokinou, Eleni; Alves, Tiago; Lardner, Robin

    2016-04-01

    Small or large oil spills resulting from accidents on oil and gas platforms or due to the maritime traffic comprise a major environmental threat for all marine and coastal systems, and they are responsible for huge economic losses concerning the human infrastructures and the tourism. This work aims at presenting the integration of oil-spill model, bathymetric, meteorological, oceanographic, geomorphological and geological data to assess the impact of oil spills in maritime regions such as bays, as well as in the open sea, carried out in the Eastern Mediterranean Sea within the frame of NEREIDs, MEDESS-4MS and RAOP-Med EU projects. The MEDSLIK oil spill predictions are successfully combined with bathymetric analyses, the shoreline susceptibility and hazard mapping to predict the oil slick trajectories and the extend of the coastal areas affected. Based on MEDSLIK results, oil spill spreading and dispersion scenarios are produced both for non-mitigated and mitigated oil spills. MEDSLIK model considers three response combating methods of floating oil spills: a) mechanical recovery using skimmers or similar mechanisms; b) destruction by fire, c) use of dispersants or other bio-chemical means and deployment of booms. Shoreline susceptibility map can be compiled for the study areas based on the Environmental Susceptibility Index. The ESI classification considers a range of values between 1 and 9, with level 1 (ESI 1) representing areas of low susceptibility, impermeable to oil spilt during accidents, such as linear shorelines with rocky cliffs. In contrast, ESI 9 shores are highly vulnerable, and often coincide with natural reserves and special protected areas. Additionally, hazard maps of the maritime and coastal areas, possibly exposed to the danger on an oil spill, evaluate and categorize the hazard in levels from low to very high. This is important because a) Prior to an oil spill accident, hazard and shoreline susceptibility maps are made available to design

  7. Mesopelagic Prokaryotes Alter Surface Phytoplankton Production during Simulated Deep Mixing Experiments in Eastern Mediterranean Sea Waters

    Directory of Open Access Journals (Sweden)

    Or Hazan

    2018-01-01

    Full Text Available Mesopelagic prokaryotes (archaea and bacteria, which are transported together with nutrient-rich intermediate-water to the surface layer by deep convection in the oceans (e.g., winter mixing, upwelling systems, can interact with surface microbial populations. This interaction can potentially affect production rates and biomass of surface microbial populations, and thus play an important role in the marine carbon cycle and oceanic carbon sequestration. The Eastern Mediterranean Sea (EMS is one of the most oligotrophic and warm systems in the world's oceans, with usually very shallow winter mixing (<200 m and lack of large-size spring algal blooms. In this study, we collected seawater (0–1,500 m in 9 different cruises at the open EMS during both the stratified and the mixed seasons. We show that the EMS is a highly oligotrophic regime, resulting in low autotrophic biomass and primary productivity and relatively high heterotrophic prokaryotic biomass and production. Further, we simulated deep water mixing in on-board microcosms using Levantine surface (LSW, ~0.5 m and intermediate (LIW, ~400 m waters at a 9:1 ratio, respectively and examined the responses of the microbial populations to such a scenario. We hypothesized that the LIW, being nutrient-rich (e.g., N, P and a “hot-spot” for microbial activity (due to the warm conditions that prevail in these depths, may supply the LSW with not only key-limiting nutrients but also with viable and active heterotrophic prokaryotes that can interact with the ambient surface microbial population. Indeed, we show that LIW heterotrophic prokaryotes negatively affected the surface phytoplankton populations, resulting in lower chlorophyll-a levels and primary production rates. This may be due to out-competition of phytoplankton by LIW populations for resources and/or by a phytoplankton cell lysis via viral infection. Our results suggest that phytoplankton in the EMS may not likely form blooms, even after

  8. Evaluating the impact of atmospheric depositions on springtime dinitrogen fixation in the Cretan Sea (Eastern Mediterranean - A mesocosm approach

    Directory of Open Access Journals (Sweden)

    Eyal Rahav

    2016-09-01

    Full Text Available Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., Sahara and Middle East are deposited annually on the surface of the Eastern Mediterranean Sea. These depositions can provide high amounts of micro (such as Fe, Zn, Co and macro nutrients (such as P and N to supplement nutrient-poor surface waters- that typically limit primary productivity and also dinitrogen (N2 fixation in many marine environments. Here, we studied the impact of the atmospheric deposition of dust and aerosols on N2 fixation in the Cretan Sea (Eastern Mediterranean Sea. Mixed polluted aerosols (hereafter A and Saharan dust (hereafter SD were added to nine mesocosms (3-m3 each containing surface mixed layer seawater (~10 m, and N2 fixation was evaluated for 6 days during May 2012 (springtime. The addition of SD triggered a rapid (30 h and robust (2-4 fold increase in N2 fixation rates that remained high for 6 days and contributed 3-8% of the primary productivity. The A addition also resulted in higher N2 fixation rates compared to the unamended control mesocosms, although the responses were less profound (1.5-2 fold and accounted for only 2-4% of the primary productivity. The microbial community responded differently to the two additions. Heterotrophic bacterial N2 fixers dominated the diazotroph community in A and the control mesocosms, while the non-filamentous cyanobacterial group Trichodesmium prevailed in the SD treatment (68% of all the operational taxonomic units, verified by qPCR analyses. Our results indicate that the aerosol source, its route prior to deposition, and its specific chemical composition, can alter the diazotrophic diversity and activity in the Eastern Mediterranean Sea and may thus impact both the N and C dynamics in this impoverished environment.

  9. Looking for evidence of climate change impacts in the eastern Irish Sea

    Directory of Open Access Journals (Sweden)

    L. S. Esteves

    2011-06-01

    Full Text Available Although storminess is often cited as a driver of long-term coastal erosion, a lack of suitable datasets has only allowed objective assessment of this claim in a handful of case studies. This reduces our ability to understand and predict how the coastline may respond to an increase in "storminess" as suggested by global and regional climate models. With focus on 16 km of the Sefton coastline bordering the eastern Irish Sea (UK, this paper analyses available measured datasets of water level, surge level, wave height, wind speed and barometric pressure with the objective of finding trends in metocean climate that are consistent with predictions. The paper then examines rates of change in shoreline position over the period 1894 to 2005 with the aim of establishing relationships with climatic variability using a range of measured and modelled metocean parameters (with time spans varying from two to eight decades. With the exception of the mean monthly wind speed, available metocean data do not indicate any statistically significant changes outside seasonal and decadal cycles. No clear relationship was found between changes in metocean conditions and rates of shoreline change along the Sefton coast. High interannual variability and the lack of long-term measurements make unambiguous correlations between climate change and shoreline evolution problematic. However, comparison between the North Atlantic Oscillation winter index (NAOw and coastline changes suggest increased erosion at times of decreasing NAOw values and reduced erosion at times of increasing NAOw values. Erosion tends to be more pronounced when decreasing NAOw values lead to a strong negative NAO phase. At present, anthropogenic changes in the local sediment budget and the short-term impact of extreme events are still the largest threat likely to affect coastal flooding and erosion risk in the short- and medium-term. Nevertheless, the potential impacts of climate change in the long

  10. Phytoplankton distributions and their nutrient environment in the Eastern Bering Sea.

    Science.gov (United States)

    Zhang, J.; Nishitani, H.; Narita, H.; Jordan, R. W.

    2004-12-01

    After 1997, coccolithophorids blooms have been frequently observed by research vessels and satellites in the Eastern Bering Sea shelf, where diatoms have previously been dominate. Here, we present CTD, Chl-a, nutrient and phytoplankton data collected during cruises of the T/S Oshoro-Maru and R/V Mirai vessels from 2000 to 2003. Our goal is to refine the relation between phytoplankton distribution and water characteristics, and the controlling features of coccolithophorids blooms in the Eearstern Bering Sea. Samplings were carried out alone 166_E#8249;W from 55_E#8249;N to 59_E#8249;N. For cell counting, seawater samples were filtered through a 25-mm Millipore HA filter, and identification and counting of phytoplankton was performed with a scanning electron microscope. The scale of bloom and abundance of coccolithophorids were different in each year. The most dominant phytoplankton group was coccolithophorids in 2000, which agrees with the large bloom observed by satellite. In 2001, diatoms dominated at 70% and coccolithophorids accounted for 30% at 58, 58.5_E#8249;N. In 2002 and 2003, diatoms dominated at nearly 100% at all stations. Coccolithophorids abundance was nearly halted by pycnocline, since coccolithophorids existed in the middle shelf domain, which is known to be an area of cold-water pool distribution. The difference in density between the surface mixed layer and the cold-water pool gradually increased from 1980 to 2002, that is, seawater stratification in the middle shelf domain was strengthened as the result of the increased surface temperature and decreased salinity that have occurred recently. When stratification strengthens, the supply of nutrients to the surface from the cold-water pool is reduced. Consequently, coccolithophorids take precedence over diatoms in this condition. However, if the decreased salinity in the surface water depended on the increased river discharge, then the nutrients in the surface water would increase. River discharge has

  11. Food-web traits of the North Aegean Sea ecosystem (Eastern Mediterranean) and comparison with other Mediterranean ecosystems

    Science.gov (United States)

    Tsagarakis, K.; Coll, M.; Giannoulaki, M.; Somarakis, S.; Papaconstantinou, C.; Machias, A.

    2010-06-01

    A mass-balance trophic model was built to describe the food-web traits of the North Aegean Sea (Strymonikos Gulf and Thracian Sea, Greece, Eastern Mediterranean) during the mid-2000s and to explore the impacts of fishing. This is the first food-web model representing the Aegean Sea, and results were presented and discussed in comparison to other previous ecosystems modelled from the western and the central areas of the basin (South Catalan and North-Central Adriatic Seas). Forty functional groups were defined, covering the entire trophic spectrum from lower to higher trophic levels. Emphasis was placed on commercial invertebrates and fish. The potential ecological role of the invasive ctenophore, Mnemiopsis leidyi, and several vulnerable groups (e.g., dolphins) was also explored. Results confirmed the spatial productivity patterns known for the Mediterranean Sea showing, for example, that the total biomass is highest in N.C. Adriatic and lowest in N. Aegean Sea. Accordingly, food-web flows and several ecosystem indicators like the mean transfer efficiency were influenced by these patterns. Nevertheless, all three systems shared some common features evidencing similarities of Mediterranean Sea ecosystems such as dominance of the pelagic fraction in terms of flows and strong benthic-pelagic coupling of zooplankton and benthic invertebrates through detritus. The importance of detritus highlighted the role of the microbial food-web, which was indirectly considered through detritus dynamics. Ciliates, mesozooplankton and several benthic invertebrate groups were shown as important elements of the ecosystem linking primary producers and detritus with higher trophic levels in the N. Aegean Sea. Adult anchovy was shown as the most important fish group in terms of production, consumption and overall effect on the rest of the ecological groups in the model, in line with results from the Western Mediterranean Sea. The five fishing fleets considered (both artisanal and

  12. GHRSST Level 4 ODYSSEA Eastern Central Pacific Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

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

  13. Viruses in a deep oligotrophic sea: Seasonal distribution of marine viruses in the epi-, meso- and bathypelagic waters of the Eastern Mediterranean Sea

    Science.gov (United States)

    Magiopoulos, Iordanis; Pitta, Paraskevi

    2012-08-01

    Marine viruses and their main hosts were studied in the Eastern Mediterranean Sea (Ionian, Libyan and Aegean Seas) during two sampling cruises (mixing and water column stratification periods). Samples were collected from the surface to 4000 m depth. Total abundance of viruses and prokaryotes was determined by Flow Cytometry (FCM). Viruses were separated into three groups according to their fluorescence signal. Viral abundance ranged from 1.2×105 viruses ml-1 to 2.7×107 viruses ml-1 and varied significantly between areas, depth zones and seasons. Prokaryotic cell abundance varied from 1.7×104 cells ml-1 to 1.5×106 cells ml-1 presenting a strong positive correlation with viral abundance. Stations and depths influenced by the Black Sea Water in the North Aegean Sea presented the highest values of viral abundance and Viruses to Prokaryotes Ratio (VPR). Vertical distributions of VPR were attributed to different water masses. The increased viral abundance and VPR values that were detected during the stratification period may be explained by the seasonal changes in prokaryotic cell characteristics (cell size, nucleic acid content). These significant seasonal distributions were also found below 1000 m indicating a possible viral activity in the bathypelagic ocean.

  14. Land-Sea relationships of climate-related records: example of the Holocene in the eastern Canadian Arctic and Greenland

    Science.gov (United States)

    de Vernal, Anne; Fréchette, Bianca; Hillaire-Marcel, Claude

    2017-04-01

    Anne de Vernal, Bianca Fréchette, Claude Hillaire-Marcel Important progresses have been made to reconstruct climate and ocean changes through time. However, there is often a hiatus between the land-based climate reconstructions and paleoceanographical data. The reconstructed parameters are not the same (e.g. surface air temperature vs. sea-surface temperature). Moreover, the spatial (local to regional) and temporal dimensions (seasonal, annual to multi-decadal) of proxy-data are often inconsistent, thus preventing direct correlation of time series and often leading to uncertainties in multi-site, multi-proxy compilations. Here, we address the issue of land-sea relationships in the eastern Canadian Arctic-Baffin Bay-Labrador Sea-western Greenland based on the examination of different climate-related information from marine cores (dinocysts) collected nearshore vs. offshore, ice cores (isotopes), fjord and lake data (pollen). The combined information tends to indicate that "climate" changes are not easily neither adequately captured by temperature and temperature shifts. However, the seasonal contrast of temperatures seems to be a key parameter. Whereas it is often attenuated offshore, it is generally easy to reconstruct nearshore, where water stratification is usually stronger. The confrontation of data also shows a relationship between ice core data and sea-ice cover and/or sea-surface salinity, suggesting that air-sea exchanges in basins surrounding ice sheets play a significant role with respect to their isotopic composition. On the whole, combined onshore-offshore data consistently suggest a two-step shift towards optimal summer and winter conditions the circum Baffin Bay and northern Labrador Sea at 7.5 and 6 ka BP. These delayed optimal conditions seem to result from ice-meltwater discharges maintaining low salinity conditions in marine surface waters and thus a strong seasonality.

  15. Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

    Directory of Open Access Journals (Sweden)

    J. Sciare

    2003-01-01

    Full Text Available A detailed study on the temporal variability of compounds important in controlling aerosol chemical composition was performed during a one-month experiment conducted during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea. Contribution of different aerosol sources in the Eastern Mediterranean Basin could be investigated at this location since the site is influenced by a wide range of air masses originating mainly in Europe and Africa. Chemical apportionment was performed for various air mass origins and showed a strong impact of anthropogenic emissions in the Turkey and Central Europe sectors, with black carbon (BC and non-sea-salt sulfate (nss-SO4 concentrations higher than observed in the Eastern and Western Europe sectors. High levels of non-sea-salt calcium (nss-Ca were associated with air masses from Africa but also from Central Turkey. Evidence was found that BC calculation based on light absorbance during dust events was biased. This quality-controlled high temporal resolution dataset allowed to investigate in detail the source-receptor relationships responsible for the levels of BC, nss-SO4 and sulfur dioxide (SO2, observed in Crete. Among the results obtained from this model, the major contribution of Turkey and Central Europe was confirmed in terms of anthropogenic emissions. Comparisons with remote optical properties obtained from Satellite observations (SEAWIFS north of Crete indicates that our ground based aerosol characterization was suitable for describing aerosol properties in the atmospheric column for most of the time during the campaign.

  16. Geomorphological map of a coastal stretch of north-eastern Gozo (Maltese archipelago, Mediterranean Sea)

    Science.gov (United States)

    Soldati, Mauro; Micallef, Anton; Biolchi, Sara; Chelli, Alessandro; Cuoghi, Alessandro; Devoto, Stefano; Gauci, Christopher; Graff, Kevin; Lolli, Federico; Mantovani, Matteo; Mastronuzzi, Giuseppe; Pisani, Luca; Prampolini, Mariacristina; Restall, Brian; Roulland, Thomas; Saliba, Michael; Selmi, Lidia; Vandelli, Vittoria

    2017-04-01

    Geomorphological investigations carried out along the north-eastern coast of the Island of Gozo (Malta) have led to the production of a detailed geomorphological map. Field surveys, accompanied by aerial photo-interpretation, were carried out within the framework of the EUR-OPA Major Hazards Agreement Project ``Developing Geomorphological mapping skills and datasets in anticipation of subsequent Susceptibility, Vulnerability, Hazard and Risk Mapping'' (Council of Europe). In particular, this geomorphological map is the main output of a `Training Course on Geomorphological Mapping in Coastal Areas' held within the Project in November 2016. The study area selected was between Ramla Bay and Dacrhlet Qorrot Bay on the Island of Gozo (67 km2), part of the Maltese archipelago in the central Mediterranean Sea. From a geological viewpoint, the stratigraphic sequence includes Late Oligocene (Chattian) to Late Miocene (Messinian) sedimentary rocks. The hard limestones of the Upper Coralline Limestone Formation, the youngest lithostratigraphic unit, dominate the study area. Underlying this formation, marls and clays belonging to the Blue Clay Formation extensively outcrop. The oldest lithostratigraphic unit observed in the study area is the Globigerina Limestone Formation, a fine-grained limestone. The lithostructural features of the outcropping units clearly condition the morphography of the landscape. The coast is characterised by the alternation of inlets and promontories. Worthy of notice is the large sandy beach of Ramla Bay partly backed by dunes. From a geomorphological perspective, the investigated coastal stretch is characterised by limestone plateaus bounded by steep structural scarps which are reshaped by gravitational and/or degradation processes, and milder slopes in Blue Clays at their foot comprising of numerous rock block deposits (rdum in Maltese) and active or abandoned terraced fields used for agricultural purposes. Landforms and processes related to

  17. Short-term variability in halocarbons in relation to phytoplankton pigments in coastal waters of the central eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Roy, R.

    The sampling locations, along the Candolim Time-Series Section (CaTS), in coastal waters of the eastern Arabian Sea, are shown in Fig. 1. Water depth at these stations varied between 6 m (G1) and 28 m (G5) whereas samples at G5 were generally collected from a... times. 6 3. Results The short-term variability of halocarbons and pigments has been presented for CaTS station G5, with a brief on hydrography. However, data from stations G1- G4 have been used to derive statistically significant relationships among...

  18. Image of the 4-m Sun-illuminated Topography of the Sea Floor off Eastern Cape Cod (CAPENORTHSUN_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes sun-illuminated of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping...

  19. Image of the 4-m Sun-illuminated Topography of the Sea Floor off Eastern Cape Cod (CAPESOUTHSUN_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes sun-illuminated of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping...

  20. 4-m Image of the Southern Half of the Backscatter Intensity Mosaic of the Sea Floor off Eastern Cape Cod from USGS Cruise 98015 (CAPESOUTHMOS_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes backscatter intensity of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping...

  1. ASCII formatted file of the 4-m bathymetry from the northern half of USGS survey 98015 of the Sea Floor off Eastern Cape Cod (CAPENORTH_GEO4M_XYZ.TXT, Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes bathymetry of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping system...

  2. ASCII formatted file of the 4-m bathymetry from the southern half of USGS Survey 98015 of the Sea Floor off Eastern Cape Cod (CAPESOUTH_GEO4M_XYZ.TXT, Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes bathymetry of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping system...

  3. CAPENORTH_GEO4M_XYZ.TXT: ASCII formatted file of the 4-m bathymetry from the northern half of USGS survey 98015 of the Sea Floor off Eastern Cape Cod (Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes bathymetry of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping system...

  4. Deep-sea coral and hardbottom habitats on the west Florida slope, eastern Gulf of Mexico

    Science.gov (United States)

    Ross, Steve W.; Rhode, Mike; Brooke, Sandra

    2017-02-01

    Until recently, benthic habitats dominated by deep-sea corals (DSC) appeared to be less extensive on the slope of the Gulf of Mexico (GOM) than in the northeast Atlantic Ocean or off the southeastern US. There are relatively few bioherms (i.e., coral-built mounds) in the northern GOM, and most DSCs are attached to existing hard substrata (e.g., authigenically formed carbonate). The primary structure-forming, DSC in the GOM is Lophelia pertusa, but structure is also provided by other living and dead scleractinians, antipatharians (black corals), octocorals (gorgonians, soft corals), hydrocorals and sponges, as well as abundant rocky substrata. The best development of DSCs in the GOM was previously documented within Viosca Knoll oil and gas lease blocks 826 and 862/906 (north-central GOM) and on the Campeche Bank (southern GOM in Mexican waters). This paper documents extensive deep reef ecosystems composed of DSC and rocky hard-bottom recently surveyed on the West Florida Slope (WFS, eastern GOM) during six research cruises (2008-2012). Using multibeam sonar, CTD casts, and video from underwater vehicles, we describe the physical and oceanographic characteristics of these deep reefs and provide size or area estimates of deep coral and hardground habitats. The multibeam sonar analyses revealed hundreds of mounds and ridges, some of which were subsequently surveyed using underwater vehicles. Mounds and ridges in <525 m depths were usually capped with living coral colonies, dominated by L. pertusa. An extensive rocky scarp, running roughly north-south for at least 229 km, supported lower abundances of scleractinian corals than the mounds and ridges, despite an abundance of settlement substrata. Areal comparisons suggested that the WFS may exceed other parts of the GOM slope in extent of living deep coral coverage and other deep-reef habitat (dead coral and rock). The complex WFS region warrants additional studies to better understand the influences of oceanography and

  5. Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae in Eastern Arabian Sea

    Directory of Open Access Journals (Sweden)

    Geetha Sasikumar

    2013-03-01

    Full Text Available Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C, distributed along the Eastern Arabian Sea (South-West coast of India. For this, the Dorsal Mantle Length (DML and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12 454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modalprogression analysis using the Bhattacharya’s method for the estimation of growth. The estimated parameters L∞ and K in von Bertalanffy Growth Function (VBGF were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort which supports the major fishery, was composed of mediumsized, fast growing individuals, whereas the second cohort (pre-monsoon cohort, comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3years for males and 2.1years for females. Negative allometric growth in weight (W with length (L was observed for males (W=0.33069.L2.5389 and females (W=0.32542.L2.6057. The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in

  6. Absolute sea levels and isostatic changes of the eastern North Sea to central Baltic region during the last 900 years

    DEFF Research Database (Denmark)

    Hansen, Jens Morten; Aagaard, Troels; Binderup, Merete

    2012-01-01

    that ice-cap growth can be faster than ice-cap melting. By comparison with 29 long-term tide gauge measurements of the region we show that the isostatic implications of the sea-level curve are in nearly perfect agreement with Peltier's global isostatic VM2 model (applied by IPCC and PSMSL) and yield a 3......±14¿cm since AD 1300 and that the Little Ice Age lowstand occurred between 1250 and 1750. Thereafter, four oscillations with a cyclicity of ~70 years peaked around 1790, 1860, 1920–1950 (double peak), and at the present. We discuss the global implications of the curve, for example that the acceleration...... in the present sea-level rise may be part of this 70-year cyclicity, and that the non-anthropogenic sea-level rise between 1700 and 1790 seems faster than the present and projected sea-level rise for the 21st century. Moreover, the conspicuous sea-level fall at the beginning of the Little Ice Age confirms...

  7. Census of biodiversity in marine caves of the eastern Mediterranean Sea

    National Research Council Canada - National Science Library

    GEROVASILEIOU, V; CHINTIROGLOU, C; VAFIDIS, D; KOUTSOUBAS, D; SINI, M; DAILIANIS, T; ISSARIS, Y; AKRITOPOULOU, E; DIMARCHOPOULOU, D; VOUTSIADOU, E

    2015-01-01

    Scientific information on the biodiversity of marine caves in the eastern Mediterranean is limited, especially when considering the extensively studied caves of the north-western and central Mediterranean...

  8. Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

    Directory of Open Access Journals (Sweden)

    L. M. Dupont

    2011-11-01

    Full Text Available Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome for the last glacial as well as for other glacial periods of the past 300 Ka.

  9. Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea.

    Directory of Open Access Journals (Sweden)

    Claudio Stalder

    Full Text Available Cold-water coral (CWC ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago. However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents.

  10. Water masses, ocean fronts, and the structure of Antarctic seabird communities: putting the eastern Bellingshausen Sea in perspective

    Science.gov (United States)

    Ribic, Christine A.; Ainley, David G.; Ford, R. Glenn; Fraser, William R.; Tynan, Cynthia T.; Woehler, Eric J.

    2015-01-01

    Waters off the western Antarctic Peninsula (i.e., the eastern Bellingshausen Sea) are unusually complex owing to the convergence of several major fronts. Determining the relative influence of fronts on occurrence patterns of top-trophic species in that area, therefore, has been challenging. In one of the few ocean-wide seabird data syntheses, in this case for the Southern Ocean, we analyzed ample, previously collected cruise data, Antarctic-wide, to determine seabird species assemblages and quantitative relationships to fronts as a way to provide context to the long-term Palmer LTER and the winter Southern Ocean GLOBEC studies in the eastern Bellingshausen Sea. Fronts investigated during both winter (April–September) and summer (October–March) were the southern boundary of the Antarctic Circumpolar Current (ACC), which separates the High Antarctic from the Low Antarctic water mass, and within which are embedded the marginal ice zone and Antarctic Shelf Break Front; and the Antarctic Polar Front, which separates the Low Antarctic and the Subantarctic water masses. We used clustering to determine species' groupings with water masses, and generalized additive models to relate species' densities, biomass and diversity to distance to respective fronts. Antarctic-wide, in both periods, highest seabird densities and lowest species diversity were found in the High Antarctic water mass. In the eastern Bellingshausen, seabird density in the High Antarctic water mass was lower (as low as half that of winter) than found in other Antarctic regions. During winter, Antarctic-wide, two significant species groups were evident: one dominated by Adélie penguins (Pygoscelis adeliae) (High Antarctic water mass) and the other by petrels and prions (no differentiation among water masses); in eastern Bellingshausen waters during winter, the one significant species group was composed of species from both Antarctic-wide groups. In summer, Antarctic-wide, a High Antarctic group

  11. Ultraphytoplankton basin-scale distribution in the eastern Mediterranean Sea in winter: link to hydrodynamism and nutrients

    Directory of Open Access Journals (Sweden)

    M. Denis

    2010-07-01

    Full Text Available The basin-scale distribution of ultraphytoplankton (<10 μm was determined in the upper 200 m of the eastern Mediterranean Sea during the winter season. Four clusters were resolved by flow cytometry on the basis of their optical properties and identified as Synechococcus, Prochlorococcus, pico- (<3 μm and nanoeukaryotes (3–10 μm. Synechococcus was the most abundant population (maximum abundance of about 37 000 cells cm−3 and contributed up to 67.7% to the overall ultraphytoplanktonic carbon biomass, whereas the contribution of Prochlorococcus never exceeded 6.5%. The maximum integrated carbon biomass was 1763, 453, 58 and 571 mg C m−2 for nanoeukaryotes, picoeukaryotes, Prochlorococcus and Synechococcus respectively. Water mass properties were analyzed on the basis of temperature and salinity distributions in order to account for the general circulation and locate the main hydrodynamic structures (fronts, gyres, transition between western and eastern basins. The effect of the main hydrodynamic structures and nutrients on the ultraphytoplankton distribution was investigated. No positive correlation between nutrients and phytoplankton could be established when considering large scales. However, below 50 m depth, nutrient ratios between particular stations were correlated to corresponding density ratios. In contrast, significant relationships were found between Synechococcus abundance and density, resulting from the impact of a gyre in southern Adriatic basin and a thermohaline front in the Ionian basin. A significant relationship was also found between picoeukaryotes and salinity in the comparison of western and eastern Mediterranean Sea.

  12. Retrospective analysis of seasonal ocean growth rates of two sea winter Atlantic Salmon in eastern Maine using historic scales

    Science.gov (United States)

    Izzo, Lisa K.; Zydlewski, Joseph D.

    2017-01-01

    Substantial declines of anadromous Atlantic Salmon Salmo salar have occurred throughout its range, with many populations at the southern extent of the distribution currently extirpated or endangered. While both one sea winter (1SW) and two sea winter (2SW) spawner numbers for the North American stocks have declined since the 1950s, the decline has been most severe in 2SW spawners. The first months at sea are considered a period of high mortality. However, early ocean mortality alone cannot explain the more pronounced decline of 2SW spawners, suggesting that the second year at sea may be more critical than previously thought. Atlantic Salmon scales collected by anglers and the state agency from 1946 to 2013 from five rivers in eastern Maine were used to estimate smolt age and ocean age of returning adults. Additionally, seasonal growth rates of maiden 2SW spawners were estimated using intercirculi measurements and linear back-calculation methods. Generalized linear mixed models (Gaussian family, log link function) were used to investigate the influence of average sea surface temperature, accumulated thermal units, the Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation indices, smolt age, smolt length, postsmolt growth, and river of origin on growth rate during the oceanic migration of North American Atlantic Salmon. Results suggest that different factors influence salmon growth throughout their oceanic migration, and previous growth can be a strong predictor of future size. Growth was negatively impacted by the phase of the AMO, which has been linked to salmon abundance trends, in early spring following the postsmolt period. This is likely when the 1SW and 2SW stock components separate, and our results suggest that this period may be of interest in future work examining the disproportionate decline in 2SW spawners.

  13. Diversity, Abundance, and Niche Differentiation of Ammonia-Oxidizing Prokaryotes in Mud Deposits of the Eastern China Marginal Seas.

    Science.gov (United States)

    Yu, Shaolan; Yao, Peng; Liu, Jiwen; Zhao, Bin; Zhang, Guiling; Zhao, Meixun; Yu, Zhigang; Zhang, Xiao-Hua

    2016-01-01

    The eastern China marginal seas (ECMS) are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were investigated in mud deposits of the South Yellow Sea (SYS) and the East China Sea (ECS) by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia, and silicate (SiO[Formula: see text]), was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ(15)NTN and SiO[Formula: see text], and nitrate and δ(13)C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO[Formula: see text]. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

  14. Small river plumes near the north-eastern coast of the Black Sea under climatic mean and flooding discharge conditions

    Science.gov (United States)

    Osadchiev, Alexander; Korshenko, Evgeniya

    2017-04-01

    The study is focused on the impact of discharge from small rivers on propagation and final location of fluvial waters and suspended matter at the north-eastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers inflow into the sea at the studied region and most of them, except the several largest of them, have small annual runoff and limitedly affect adjacent coastal waters under climatic mean conditions. However, discharges of these small rivers are characterized by quick response to precipitation events and can dramatically increase during and shortly after heavy rains, which are frequent in the area under consideration. Propagation and final location of fluvial waters and terrigenous sediments at the studied region under climatic mean and rain-induced flooding conditions were explored and compared using in situ data, satellite imagery and numerical modelling. It was shown that the point-source spread of continental discharge dominated by several large rivers during climatic mean conditions can change to the line-source discharge from numerous small rivers situated along the coast in response to heavy rains. Intense line-source runoff of water and suspended sediments form a geostrophic alongshore current of turbid and freshened water, which induces intense transport of suspended and dissolved constituents discharged with river waters in a north-western direction. This process significantly influences water quality and causes active sediment load at large segments of narrow shelf at the north-eastern part of the Black Sea as compared to climatic mean discharge conditions.

  15. Comparative Morphometric Analysis of the Smallscaled Scorpionfish, Scorpaena Porcus (Scorpaenidae, Scorpaeniformes, from the Southern Coast of the Crimea and Eastern Part of the Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Manilo L. G.

    2016-12-01

    Full Text Available Comparative analysis of morphometric characters of small-scaled scorpionfish from the Black Sea (near the southern coast of the Crimea and from the eastern part of the Adriatic Sea showed significant differences in males and females on thirteen plastic and three meristic characters. These differences may be due to unequal abiotic and biotic habitat conditions, and refer about the geographical variability of the species, indicating the presence of two different populations in the study area.

  16. Qualitative and quantitative composition of microplastics particles during the expeditionary measurement program in the South-Eastern Baltic Sea

    Science.gov (United States)

    Esiukova, Elena; Bagaeva, Margarita; Chubarenko, Natalia

    2016-04-01

    According to the tasks of the Russian Science Foundation project "Physical and dynamical properties of marine microplastics particles and their transport in a basin with vertical and horizontal salinity gradient on the example of the Baltic Sea" number 15-17-10020, a comprehensive expeditionary program of measurements in the South-Eastern Baltic started. The project is aimed at finding solutions for a number of problems caused by superfluous plastic pollution in the World Ocean and, in particular, in the Baltic Sea. This pollution has been accumulating for years and just recently it has become obvious that only multidisciplinary approach (geographical, biological, chemical, etc.) to the issues related to the processes of transformation of properties and propagation of plastic particles will allow the study of physical aspects of the problem. During the first stage of the study samples should be selected from the water surface, water column at various horizons, bottom sediments in the Baltic Sea, from different areas at the beaches - in order to further examine the qualitative and quantitative composition of microplastic particles in different seasons for different hydrophysical situations. Reconnaissance survey was begun to choose the fields for research close to point and distributed sources of microplastics. Preference is given to those beaches that are exposed to maximum anthropogenic pollution: areas around the town of Baltiysk, the northern part of the Vistula Spit (near the settlement of Kosa), and the Sambia peninsula coast (settlements of Yantarny, Donskoye, Primorye, Kulikovo, towns of Svetlogorsk, Pionersky, Zelenogradsk). Locations for experimental sites were found in order to assess time for formation of microplastics (Vistula Spit, Kosa settlement). In June-November, 2015 there were 5 expeditions in the waters of the South-Eastern Baltic, 7 expeditions along the coast line of the Baltic Sea (in Kaliningrad Oblast), and 5 expeditions to the Vistula

  17. Sedimentological and paleontological features of sea floor sediments of Penta Palummo and Miseno volcanic highs, Gulf od Naples (South-eastern Tyrrhenian Sea)

    Energy Technology Data Exchange (ETDEWEB)

    Ferraro, L.; Molisso, F. [Consiglio Nazionale delle Ricerche, Naples (Italy). Ist. di Ricerca Geomare Sud

    2000-07-01

    A sedimentological and paleontological study has been carried out on surficial sediments of Penta Palummo and Miseno volcanic banks, in the Gulf of Naples (South-eastern Tyrrhenian Sea, Italy). The deposits consist of bioclastic sand (coralline algae, bryozoans, gastropods, bivalvs and echinoderms). The benthic foraminiferal assemblage is mainly characterized by epiphytic species. Bioclastics sand is autochtonous and derived from breakdown of algal buildups. [Italian] Uno studio sedimentologico e paleontologico e' stato condotto sui sedimenti superficiali dei banchi vulcanici di Penta Palummo e di Miseno (Golfo di Napoli, Mar Tirreno sudorientale). I depositi sono costituiti da sabbie bioclastiche (alghe coralline, briozoi, gasteropodi, bivalvi ed echonodermi). L'associazione a foraminiferi bentonici e' caratterizzata principalmente da specie epifite. Le sabbie bioclastiche sono autoctone e derivano dal disfacimento di biocostruzioni algali.

  18. Temperature, salinity, oxygen and other measurements collected in the Scotia Sea from 04 August 1997 to 05 September 1997 (NODC Accession 0000753)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and other data were collected using bottle and CTD casts in the Weddell and Scotia Sea from NATHANIEL B. PALMER. Data were collected from 04...

  19. The Late-Pleistocene sedimentation history in the Eastern Arabian Sea: Climate Weathering-Productivity linkage

    Digital Repository Service at National Institute of Oceanography (India)

    Chodankar, A.R.

    observations such as the Indian Monsoons providing important feedback for global climate change, Arabian Sea hosting high productivity and intense denitrification, and the past changes in the Indian Monsoons correlating with the northern high latitude Dansgaard...

  20. Influence of eastern Arabian Sea on summer monsoon rainfall over west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Rao, M.S.; Rao, M.V.

    Sea surface temperature (SST) anomalies have been assigned as one of the boundary conditions in the global circulation models for simulation of climatic changes. The effects of SST anomalies on the summer monsoon simulations are both of local...

  1. Seasonal variations in inorganic carbon components in the central and eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; George, M.D.; Rajendran, A.

    Extensive observations have been made on the carbon dioxide system in the Arabian Sea during three different seasons as part of the Indian Joint Global Ocean Flux Study (JGOFS) Programme. Concentrations of total carbon dioxide and partial pressure...

  2. Monsoonal reversal of remote sensing biases in latent heat flux over eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Pankajakshan, T.; Sathe, P.V.; Murty, V.S.N.; Santosh, K.R.

    The Arabian Sea is a unique basin where a number of atmospheric and oceanographic processes occur due to the contrasting climatic conditions, which it experiences. The drastic monsoonal variability occurring in the boundary layer adversely affects...

  3. A quantitative catalogue of intertidal and near shore birds habitats of Eastern Bering Sea

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bering Sea waterbird habitats include four types; the shallow usually near shore waters where diving birds can feed on the bottom, the sheltered waters of lagoons...

  4. AFSC/RACE/GAP/Yeung: Eastern Bering Sea Essential Fish Habitat Benthic Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic samples were collected between 2009-2012 in the Bering Sea to study Essential Fish Habitat. Station locations were at or near fixed stations of the AFSC...

  5. Mud Volcanism and Fluid Venting In The Eastern Mediterranean Sea: Observations From Sidescan Sonar and Submersible Surveys

    Science.gov (United States)

    Zitter, T. A. C.; Huguen, C.; Woodside, J. M.; Mascle, J.; Scientific Party, Medineth/Medinaut

    Mud volcanoes in the eastern Mediterranean Sea have been identified by their distinctive acoustic signature as well as their morphology and sedimentology. They appear as circular regions of high backscatter believed to be caused principally by the clast content of the mud flows forming the mud volcano. Both the MEDINAUT and MEDINETH expeditions, conducted in 1998 and 1999 over two mud fields, the Olimpi field and the Anaximander Mountains area, in Eastern Mediterranean Sea, studied mud volcanism using a multidisciplinary approach in order to determine the relationships between the activity of the mud volcanoes (importance of degassing, associated fauna) and their geophysical signature. Mud volcanoes in Eastern Mediterranean Sea vary from conical and dome-shaped reliefs from 500m to 2km wide and 100 to 200m high to large "mud pie" types up to 6km wide. Sidescan sonar records give a very high resolution of the acoustic response, enabling to distinguish several mud flows, often flowing along tectonic lineations. A clear relationship between the occurrence of mud volcanism and cold seeps and both thrust and transcurrent faulting has been observed in both mud fields, although the tectonic settings vary from purely compressional to a more transpressional stress field. The faults are inferred to provide pathways for over- pressured fluids, and secondary faulting (transcurrent and extensional faults) may facilitate mud ascension. On the basis of sidescan sonar interpretation, other typical features have been inferred such as main feeder channels, eruptive cone centers, or brine pools. The in situ observations have been used to characterize the seafloor over numerous mud volcanoes and ground-truth the sonar data. They reveal an abundance of fluid seeps, mainly methane and methane-rich brines, as well as associated specific fauna such as tube worms, clams and chemosynthetic bacteria, and specific diagenetic phenomenon i.e. carbonate crusts. Video observations proved that

  6. Variations in swells along Eastern Arabian Sea during the summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Johnson, G.; SanilKumar, V.; Sanjiv, P.C.; Singh, J.; Pednekar, P.S.; AshokKumar, K.; Dora, G.U.; Gowthaman, R.

    facilities. The presence of local wind sea and swell components propagating from distant storms can be identified by studying wave energy spectra. When seas and swells are present the wave energy spectrum will be multi-peaked with peaks corresponding...- responding to the maximum spectral energy density is referred as spectral peak period (Tp) and is estimated from the wave spectrum. Other parameters obtained were spectral narrowness parameter () [6] and the maximum spectral energy. Zero...

  7. Sequence stratigraphy and a revised sea-level curve for the Middle Devonian of eastern North America

    Science.gov (United States)

    Brett, Carlton E.; Baird, G.C.; Bartholomew, A.J.; DeSantis, M.K.; Ver Straeten, C.A.

    2011-01-01

    The well-exposed Middle Devonian rocks of the Appalachian foreland basin (Onondaga Formation; Hamilton Group, Tully Formation, and the Genesee Group of New York State) preserve one of the most detailed records of high-order sea-level oscillation cycles for this time period in the world. Detailed examination of coeval units in distal areas of the Appalachian Basin, as well as portions of the Michigan and Illinois basins, has revealed that the pattern of high-order sea-level oscillations documented in the New York-Pennsylvania section can be positively identified in all areas of eastern North America where coeval units are preserved. The persistence of the pattern of high-order sea-level cycles across such a wide geographic area suggests that these cycles are allocyclic in nature with primary control on deposition being eustatic sea-level oscillation, as opposed to autocylic controls, such as sediment supply, which would be more local in their manifestation. There is strong evidence from studies of cyclicity and spectral analysis that these cycles are also related to Milankovitch orbital variations, with the short and long-term eccentricity cycles (100. kyr and 405. kyr) being the dominant oscillations in many settings. Relative sea-level oscillations of tens of meters are likely and raise considerable issues about the driving mechanism, given that the Middle Devonian appears to record a greenhouse phase of Phanerozoic history. These new correlations lend strong support to a revised high-resolution sea-level oscillation curve for the Middle Devonian for the eastern portion of North America. Recognized third-order sequences are: Eif-1 lower Onondaga Formation, Eif-2: upper Onondaga and Union Springs formations; Eif-Giv: Oatka Creek Formation; Giv-1: Skaneateles, Giv-2: Ludlowville, Giv-3: lower Moscow, Giv-4: upper Moscow-lower Tully, and Giv-5: middle Tully-Geneseo formations. Thus, in contrast with the widely cited eustatic curve of Johnson et al. (1985), which

  8. Mud volcanoes and gas hydrates in the Anaximander mountains (Eastern Mediterranean Sea)

    NARCIS (Netherlands)

    Lykousis, V.; Alexandri, S.; Woodside, J.M.; de Lange, G.; Dahlmann, A.; Perissoratis, C.; Heeschen, K.; Ioakim, Chr.; Sakellariou, D.; Nomikou, P.; Rousakis, G.; Casas, D.; Ballas, D.; Ercilla, G.

    2009-01-01

    Detailed multibeam, sedimentological, and geophysical surveys provide ample new data to confirm that the Anaximander Mountains (Eastern Mediterranean) are an important area for active mud volcanism and gas hydrate formation. More than 3000 km of multibeam track length was acquired during two recent

  9. Distribution pattern and mass budget of sedimentary polycyclic aromatic hydrocarbons in shelf areas of the Eastern China Marginal Seas

    Science.gov (United States)

    Wang, C. L.; Zou, X. Q.; Zhao, Y. F.; Li, Y. L.; Song, Q. C.; Wang, T.; Yu, W. W.

    2017-06-01

    This study conducted the first extensive and comprehensive investigation of the regional-scale sedimentary polycyclic aromatic hydrocarbons (PAHs) concentration, flux, and budget in the continental shelves of the Eastern China Marginal Seas (ECMSs). Surface sediment samples from multiple sites were collected and assessed, and the latest data from current research were assessed. The spatial distribution pattern of PAHs in the ECMSs was significantly influenced by the regional hydrodynamics, sediment properties (grain-size, total organic carbon [TOC] content, and sedimentation rate), and anthropogenic impacts. Relatively higher PAHs concentrations occurred in areas with fine-grained sediment. Results of source apportionment found that the relative proportions of PAHs showed significant regional variation, mainly influenced by socioeconomic differences between north and south China. The PAHs burial flux in the study area ranged from 11.2 to 1308 ng cm-2 yr-1 with an average value of 101 ± 104 ng cm-2 yr-1. The area-integrated sedimentary PAHs burial flux across the ECMSs was 494 t yr-1. A mass budget calculation revealed that riverine input and atmospheric deposition were the most significant sources contributing, 28.4% and 71.6%, respectively. The study demonstrated that net PAHs transportation occurs between the Bohai Sea (BS) and Yellow Sea (YS), with a flux of approximately 10.2 t yr-1. PAHs were also transported from YS to the East China Sea (ECS), due to water exchange between the YS and ECS. Additionally, substantial amounts of PAHs in the inner shelf of the ECS were transported out of the shelf area due to cross-shelf plume.

  10. 16S rRNA-based bacterial diversity in the organic-rich sediments underlying oxygen-deficient waters of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Divya, B.; Parvathi, A.; LokaBharathi, P.A.; Nair, S.

    =UTF-8 Author version: World J. Microbiol. Biotechnol., vol.27; 2011; 2821-2833 16S rRNA-based bacterial diversity in the organic-rich sediments underlying oxygen deficient waters of eastern Arabian Sea Baby Divya 1 , Ammini Parvathi 2 , P. A...

  11. Morphological recognition of Globigerinoides ruber morphotypes and their susceptibility to diagenetic alteration in the eastern Mediterranean Sea

    Science.gov (United States)

    Kontakiotis, G.; Antonarakou, A.; Mortyn, P. G.; Drinia, H.; Anastasakis, G.; Zarkogiannis, S.; Möbius, J.

    2017-10-01

    Planktonic foraminiferal geochemistry presents a valuable archive for paleoceanographic reconstructions. However in high salinity and carbonate super-saturated settings, precipitation of inorganic calcite onto foraminiferal tests can potentially alter the primary geochemical signal, biasing Mg/Ca ratios and ensuing paleoceanographic reconstructions. Here we utilize test biometrics (specifically related to the compression and elongation of the last chambers) to identify four distinct morphotypes (labelled A-D) of the paleoceanographically important planktonic foraminifer species Globigerinoides ruber, and further evaluate their susceptibility to diagenetic alteration from a suite of surface sediments in the eastern Mediterranean Sea. The three distinguished morphotypes (A-C) correspond to previously recognized morphotypes (;Normal;, ;Platys;, ;Elongate; respectively) in the Mediterranean Sea, while the remaining (D or ;Twin;) was designated for the first time. We also compare Scanning Electron Microscopy (SEM) observations performed on four distinguished morphotypes, indicative of potential diagenetic alteration influence. We identified 3 different overgrowth stages (OGA1-OGA3), as a function of geography in the study area. The early diagenesis degrees (involving all the morphotypes) are only geographically distinct along the eastern Mediterranean (increasing to the south), since the morphology does not play a role in the likelihood of diagenetic alteration. Particularly, in the north Aegean Sea, SEM analyses reveal the absence or limited presence of an overgrowth imprint in all recognized morphotypes, while in the central-south Aegean and Levantine Seas they show higher amplitudes of diagenetic overprint supporting the general trend to advanced diagenetic alteration. The semi-enclosed oligotrophic nature and high salinity of this setting, in combination with the different degree of carbonate precipitation and calcite super-saturation between the sub-basins, could

  12. Inshore capture-based tuna aquaculture impact on Posidonia oceanica meadows in the eastern part of the Adriatic Sea.

    Science.gov (United States)

    Kružić, Petar; Vojvodić, Vjeročka; Bura-Nakić, Elvira

    2014-09-15

    Mapping and monitoring of the seagrass Posidonia oceanica in the eastern (Croatian) part of the Adriatic Sea since 2004 indicates a significant decline in meadow density in an area impacted by inshore capture-based tuna aquaculture. The density and overall condition of P. oceanica meadows impacted by tuna farms near Fulija Islet was compared to two reference sites (Iž Island and Mrtovnjak Islet). The factors with the most significant influence on P. oceanica meadows were found to be the input of organic matter originating from the cages, as well as high epiphyte biomass caused by nutrient enrichment. Significant differences in nutrient concentrations were found between the sites impacted by tuna farms (Fulija Islet) and the control stations. Shoot density of the P. oceanica meadows decreased at the stations in close vicinity to the tuna farm, which suggests that the tuna farm activity strongly affected the surrounding meadows. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Inter-cohort growth patterns of pharaoh cuttlefish Sepia pharaonis (Sepioidea: Sepiidae in Eastern Arabian Sea

    Directory of Open Access Journals (Sweden)

    Geetha Sasikumar

    2013-03-01

    Full Text Available Sepia pharaonis is an important commercial species endemic to the tropical Indo-Pacific region. Despite its commercial significance, only few information on natural populations is available. This study was aimed to describe the aspects of size-composition, length-weight relationship, catch rates, seasonal recruitment and inter-cohort growth patterns of S. pharaonis population (Clade C, distributed along the Eastern Arabian Sea (South-West coast of India. For this, the Dorsal Mantle Length (DML and weight of cuttlefishes was obtained from commercial trawl catches, from April 2002 to October 2006. Data was analyzed by normal length-weight methods such as von Bertalanffy. A total of 12 454 cuttlefishes, ranging in length from four to 41cm were analyzed. Size-composition patterns discriminated two pulses in recruitment to the fishery, discernible by a decrease in the monthly mean size of the population. The DMLs of the two seasonal cohorts were subjected to modalprogression analysis using the Bhattacharya’s method for the estimation of growth. The estimated parameters L∞ and K in von Bertalanffy Growth Function (VBGF were used to model growth curves in length for the cohorts. The first cohort, (post-monsoon cohort which supports the major fishery, was composed of mediumsized, fast growing individuals, whereas the second cohort (pre-monsoon cohort, comprised of slow growing and large-sized individuals. There were differential growth characteristics between the sexes and the life span was estimated at less than 2.3years for males and 2.1years for females. Negative allometric growth in weight (W with length (L was observed for males (W=0.33069.L2.5389 and females (W=0.32542.L2.6057. The females were heavier compared to males at any given mantle length, and the males were found to attain larger ultimate lengths. The major fishing season for cuttlefish was from May to November, when higher monthly catch rates of 1.67-13.02kg/h were observed in

  14. Modelling of oil spills in confined maritime basins: The case for early response in the Eastern Mediterranean Sea.

    Science.gov (United States)

    Alves, Tiago M; Kokinou, Eleni; Zodiatis, George; Lardner, Robin; Panagiotakis, Costas; Radhakrishnan, Hari

    2015-11-01

    Oil spill models are combined with bathymetric, meteorological, oceanographic, and geomorphological data to model a series of oil spill accidents in the Eastern Mediterranean Sea. A total of 104 oil spill simulations, computed for 11 different locations in the Levantine Basin, show that oil slicks will reach the coast of Cyprus in four (4) to seven (7) days in summer conditions. Oil slick trajectories are controlled by prevailing winds and current eddies. Based on these results, we support the use of chemical dispersants in the very few hours after large accidental oil spills. As a corollary, we show shoreline susceptibility to vary depending on: a) differences in coastline morphology and exposure to wave action, b) the existence of uplifted wave-cut platforms, coastal lagoons and pools, and c) the presence of tourist and protected environmental areas. Mitigation work should take into account the relatively high susceptibility of parts of the Eastern Mediterranean. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    DEFF Research Database (Denmark)

    Pedersen, Stig A. Schack; Boldreel, Lars Ole

    2017-01-01

    of conventional seismic profiles located about 10km offshore the west coast of northern Denmark. The deformed bedrock includes the main part of the Cretaceous Chalk Group in the North Sea. In the northern part of the complex the detachment surface is situated in Lower Cretaceous greensand about 400m below sea...... level. In the central part of the complex, the thrusting ramps the strong reflectors at the base of the Chalk Group and the detachment surface continues in the lower part of the Upper Cretaceous chalk. In the tectonic depression north of the complex, marine and glaciomarine deposits represent the Eemian...... depression, i.e. early stage of the Norwegian Trench....

  16. Data from investigation on seismic Sea-waves events in the Eastern Mediterranean from the Birth of Christ to 500 A.D.

    Directory of Open Access Journals (Sweden)

    J. ANTONOPOULOS

    1980-06-01

    Full Text Available The Eastern Mediterranean has a long history of damaging seismic sea
    waves (Tsunamis but a great number of them which are locally generated are small. They have caused no serious damage to the coasts because their
    energy is confined by many islands of the Greek Archipelagos. However,
    some of them have been rather severe and destructive to property and
    human life.
    This paper is comprised of data from an investigation into the activity
    of seismic sea waves in the Eastern Mediterranean from the Birth of
    Christ to 500 A.D. It contains a great amount of information concerning
    earthquakes, volcanic eruptions and seismic sea waves.
    All the available information has been compiled from historical accounts,
    archives, press reports, magazines and related works.

  17. Antarctophthirus carlinii (Anoplura: Echinophthiriidae), a new species from the Weddell seal Leptonychotes weddelli.

    Science.gov (United States)

    Leonardi, María Soledad; Poljak, Sebastián; Carlini, Pedro; Galliari, Juan; Bobinac, Magalí; Santos, Mercedes; Márquez, María E; Negrete, Javier

    2014-11-01

    As a part of an ongoing long-term study on the biology of pack-ice seals in Antarctica, we had the opportunity to collect lice from Weddell seals (Leptonychotes weddelli). We did not find the original description of this host-parasite association. Antarctophthirus ogmorhini had previously been reported as a parasite for the Weddell seal, but the information is, to a certain extent, confusing. During the development of the present study, we had access to literature concerning the presence of A. ogmorhini on this host, which, to our knowledge, was not determined in any of the previous works on this species. We compared lice collected from Weddell seals with A. ogmorhini obtained from the type host, the leopard seal (Hydrurga leptonyx), and we found that both species can be distinguished. The main differences are the characteristic pattern of chaetotaxy in the dorsal side of the head in lice from Weddell seals, the size and form of the pseudopenis, and the distribution and size of the fringe of setae surrounding the genital opening. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we proposed that lice from Weddell seals constitute a new species. In the present work, we described and illustrated adults of this new species collected from Weddell seals during the austral summer of 2014 at the Danco Coast, Antarctic Peninsula.

  18. Trace metal concentrations in zooplankton from the eastern Arabian Sea and western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rejomon, G.; Balachandran, K.K.; Nair, M.; Joseph, T.; DineshKumar, P.K.; Achuthankutty, C.T.; Nair, K.K.C.; Pillai, N

    Trace metal contents in zooplankton samples were estimated as a part of the Marine Research-Living Resource program at 24 stations in the Bay of Bengal (November, 2002) and 29 stations in the Arabian Sea (September-October, 2003) during the Cruises...

  19. Assessing Evaporation Duct Variability In The Eastern Mediterranean Sea In Support Of Radar And Radio Communications

    Science.gov (United States)

    2016-12-01

    discovered that EDSs were highest in the fall and between 12 and 15 UTC. Spatial and diurnal variations of EDS were strongest in the fall. In other seasons...F. J. and F. Criado-Aldeanueva, 2012: Model thermohaline trends in the Mediterranean Sea during the last years: A change with respect to the last

  20. Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

    (0-200 m) than in the surface (0-10 m) tows. Further, latitudinal gradient of some species which have a definite bearing on hydrography of the sea, has been outlined. Relative production of planktonic foraminifera shows that it is high in the southern...

  1. Enhanced salinities, as a proxy of seawater desalination discharges, impact coastal microbial communities of the eastern Mediterranean Sea.

    Science.gov (United States)

    Belkin, Natalia; Rahav, Eyal; Elifantz, Hila; Kress, Nurit; Berman-Frank, Ilana

    2015-10-01

    Seawater desalination plants increase local coastal salinities by discharging concentrated brine back to the sea with ∼ 50% higher than ambient salinities. The impacts of high salinities on microbial coastal populations of the eastern Mediterranean Sea (EMS) were examined in two mesocosm experiments; first, during the mixed-spring and second, during the stratified-summer periods with average salinity of ∼ 39. Ambient salinities were increased by 5% and 15%. Higher salinity (15%) mesocosms induced rapid (within 2 h) declines in both primary productivity (PP) and algal biomass parallel to an increase in bacterial productivity. Subsequently, for the duration of the experiments (11-12 days), both Chlorophyll a and PP rates increased (2 to 5 and 1.5 to 2.5-fold, respectively) relative to unamended controls. The initial assemblages of the ambient microbial populations and intensity of salinity enrichments influenced the community responses. During the mixed-spring experiment, the composition of prokaryotic and eukaryotic populations shifted only slightly, suggesting high functional plasticity of the initial populations. While during the stratified-summer experiment, high salinity changed the composition and reduced the biodiversity of the microbial communities. In an ultra-oligotrophic environment such as the EMS, salinity induced declines in microbial diversity may provide a tipping point destabilizing the local aquatic food web. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. New evidence of the Monchique - Madeira hot spot volcanism at the Coral Patch seamount, Central Eastern Atlantic Sea

    Science.gov (United States)

    D'Oriano, F.; Angeletti, L.; Laurenzi, M. A.; Trua, T.; Capotondi, L.; Taviani, M.; Torelli, L.; Zitellini, N.

    2009-12-01

    Detailed swath bathymetry, high resolution seismic profiles and bottom sampling, collected during the SWIM 2005 and SWIM 2005 cruises, provide new data to constrain the emplacement mechanism of the Monchique-Madeira hotspot in the Central - Eastern Atlantic Sea. During last decades, although this volcanic province has been the object of several investigations, the location of hotspot track and the alignments of the volcanic centers, such as Ormonde, Ampere and Coral Patch seamounts, are still matter of debate. Several alkaline volcanic centers are recognized at Coral Patch and volcanic rocks obtained from the top of the seamount provides a radiometric (40Ar-39Ar) age of 31.4±1.98 Ma. Our data suggest that volcanism was emplaced on the top of a preexistent seamount and was strongly affected by the regional tectonic compressive regime, active on this sector of the Africa Eurasia plate boundary since Oligocene. The compression formed lithospheric scale structures acting as a reserved lane for the upwelling of mantle material during the transit of the hotspot. Lithified pelagic carbonates, infilling fissures in lava blocks and hosting planktic foraminifers, permit to date at the Chattian (24-28 Ma) the first documentation of Coral Patch acting as an offshore terrigenous-starved deep seamount. This situation protracts to recent times as shown by the occurrence of veneers of foraminifer-pteropod oozes and deep-sea mollusc-coral hash and pelagic limestones as the sole sediment types recovered from Coral Patch.

  3. Zooplankton composition along the confinement gradient of the Taranto Sea System (Ionian Sea, south-eastern Italy)

    Science.gov (United States)

    Belmonte, Genuario; Vaglio, Irene; Rubino, Fernando; Alabiso, Giorgio

    2013-12-01

    A 2-year study was conducted on 4 interconnected, progressively more confined coastal basins with the aim of describing zooplankton composition and its dynamics. A total of 346 taxa (175 species) were recorded. 24 species were new records for the Italian fauna. Taxa richness was partly attributed to the intense sampling effort. Using an additional net with narrower mesh sizes enabled to enrich the taxa list, and a correct estimation of the abundances, especially for the smaller species. Regarding spatial partitioning, 87.5% of categories were linked to only 1 or 2 adjacent sampling stations. Regarding time partitioning, 80.6% of categories showed an intermittent presence (seasonality). Distance from the open sea (confinement) was found to be directly correlated with the numerical abundance of specimens and its variability. In contrast, it was inversely correlated with species richness. Cumulative data after 2 years, confirmed the inverse correlation of species number with confinement. However, the final species richness led to less important differences between the four basins. A comparison with data from 1990 to 91 highlighted substantial differences in zooplankton composition. However, in one case it has been demonstrated that the difference was due to the difficulty in correctly estimating species number in confined habitats.

  4. Spring Bloom Dynamics of the Eastern Bering Sea Shelf as Estimated from Oxygen/Argon Ratios and Triple Oxygen Isotopes

    Science.gov (United States)

    Prokopenko, M.; Granger, J.; Mordy, C. W.; Difiore, P.; Cassar, N.; Cokelet, E.; Kachel, N. B.; Kachel, D. N.; Sambrotto, R.; Moran, B.

    2008-12-01

    The Bering Sea's position at the end of the global ocean "conveyor belt" and shoaling of nutrient rich water masses onto its broad shelf make the Eastern Bering Sea shelf one of the most productive regions of the polar oceans, with reported annual primary production rates of 150 to 500 gC*m-2 yr-1. Much of this production occurs during spring blooms, which follow the inception of water column stratification after the retreat of sea-ice. The fate of the bloom biomass determines the amount of the export production available to higher trophic levels in the shelf ecosystem, but due to the hydrographic variability of the ice edge regime direct measurements of productivity rates are not easily extrapolated in space and time. Hence, a more integrative approach is needed. Here we report estimates of Net Community and Gross Photosynthetic Production rates (GPP and NCP) obtained from O2/Ar and triple oxygen isotope ratios measured as a part of the BEST (Bering Sea Ecosystem Study) project during six weeks of spring 2007. Under steady state conditions, NCP and new production should be stoichiometrically equivalent to net photosynthetic O2 production and can be estimated from oxygen air-sea exchange fluxes. In this study, O2/Ar ratios, used to distinguish between biological and physical components of oxygen flux, were measured continuously by a quadrupole mass spectrometer equipped with an Equilibrator Inlet (EIMS, modified from Kaiser et al., 2005). To calibrate EIMS results, discrete samples were collected from the ship's underway seawater system and from hydrocasts. Dissolved O2 and Ar were cryogenically isolated and extracted offline and analyzed on an IRMS at the Geosciences Dept, Princeton Univ. To estimate the rates of gross photosynthetic production, oxygen triple isotope ratios of dissolved O2 were measured on the same discrete samples. Ventilation rates (piston velocities) were calculated based on Quikscat wind speeds and the parameterization of Wanninkhof (1992

  5. Eastern Mediterranean sea levels through the last interglacial from a coastal-marine sequence in northern Israel

    Science.gov (United States)

    Sivan, D.; Sisma-Ventura, G.; Greenbaum, N.; Bialik, O. M.; Williams, F. H.; Tamisiea, M. E.; Rohling, E. J.; Frumkin, A.; Avnaim-Katav, S.; Shtienberg, G.; Stein, M.

    2016-08-01

    A last interglacial (Marine Isotope Stage, MIS5e) marine-coastal sequence has been identified along the Galilee coast of Israel, with the type section located at Rosh Hanikra (RH). The microtidal regime and tectonic stability, along with the detailed stratigraphy of the RH shore, make the study region ideally suited for determining relative sea level (RSL) through the MIS5e interval in the eastern Mediterranean. The sequence contains fossilized microtidal subunits at a few meters above the current sea level. Unfortunately, all fossils were found to be altered, so that U-Th datings cannot be considered to represent initial deposition. We contend that U-Th dating of Strombus bubonius shells (recrystallized to calcite) suffices to indicate a lower limit of ∼110 ± 8 ka for the time sea level dropped below the RH sedimentary sequence. The RH-section comprises three main subunits of a previously determined member (the Yasaf Member): (a) a gravelly unit containing the diagnostic gastropod Strombus bubonius Lamarck (Persististrombus latus), which was deposited in the intertidal to super-tidal stormy zone; (b) Vermetidae reef domes indicating a shallow-water depositional environment; and (c) coarse to medium-sized, bioclastic sandstone, probably deposited in the shallow sub-tidal zone. The sequence overlies three abrasion platforms that are cut by tidal channels at elevations of +0.8 m, +2.6 m and +3.4 m, and which are filled with MIS5e sediments. We present a detailed study of the sequence, with emphasis on stratigraphic, sedimentological, and palaeontological characteristics that indicate sea-level changes. Although without precise absolute dating, the stratigraphic sequence of RH through MIS5e allows us to identify a time-series of RSL positions, using the elevations of three stratigraphic subunits. Reconstructed RSL values range from +1.0 m to +7 m (with uncertainly < 1 m), and most fall within a narrow range of +1.0 to +3.3 m. Toward the end of MIS5e, RSL exceeded

  6. Sedimentary sources and processes in the eastern Arabian Sea: Insights from environmental magnetism, geochemistry and clay mineralogy

    Directory of Open Access Journals (Sweden)

    Kumar Avinash

    2016-03-01

    Full Text Available The spatial distribution patterns of surficial sediment samples from different sedimentary domains (shallow to deep-sea regions of the eastern Arabian Sea were studied using sediment proxies viz. environmental magnetism, geochemistry, particle size and clay mineralogy. Higher concentrations of magnetic minerals (high χlf were recorded in the deep-water sediments when compared with the shallow water sediments. The magnetic mineralogy of one of the shallow water samples is influenced by the presence of bacterial magnetite as evidenced from the χARM/χlf vs. χARM/χfd biplot. However, the other samples are catchment-derived. The high correlation documented for χlf, anhysteretic remanent magnetisation (χARM and isothermal remanent magnetisation (IRM with Al indicates that the deep-sea surficial sediments are influenced by terrigenous fluxes which have been probably derived from the southern Indian rivers, the Sindhu (the Indus and the Narmada-Tapti rivers. A lower Mn concentration is recorded in the upper slope sediments from the oxygen minimum zone (OMZ but a higher Mn/Al ratio is documented in the lower slope and deep-sea sediments. Clay minerals such as illite (24–48.5%, chlorite (14.1–34.9%, smectite (10.6–28.7% and kaolinite (11.9–27.5% dominate the sediments of shallow and deep-sea regions and may have been derived from different sources and transported by fluvial and aeolian agents. Organic carbon (OC data indicate a low concentration in the shallow/shelf region (well oxygenated water conditions and deeper basins (increased bottom-water oxygen concentration and low sedimentation rate. High OC concentrations were documented in the OMZ (very low bottom-water oxygen concentration with high sedimentation rate. The calcium carbonate concentration of the surface sediments from the continental shelf and slope regions (<1800 m up to the Chagos-Laccadive Ridge show higher concentrations (average = 58% when compared to deep basin

  7. MAPPING SUBSURFACE FORMATIONS ON THE EASTERN RED SEA COAST IN JORDAN USING GEOELECTRICAL TECHNIQUES: GEOLOGICAL AND HYDROGEOLOGICAL IMPLICATIONS

    Directory of Open Access Journals (Sweden)

    Batayneh Awni T.

    2007-12-01

    Full Text Available During 2006, geoelectrical measurements using the vertical electrical sounding (VES method were conducted on the eastern Red Sea coast in Jordan, using the SYSCAL-R2 resistivity instrument.
    The objectives of the study were (i to evaluate the possibility of mapping of Quaternary sediments medium in areas where little is known about the subsurface geology and to infer shallow geological
    structure from the electrical interpretation, and (ii to identify formations that may present fresh aquifer waters, and subsequently to estimate the relationship between groundwater resources and geological structures. Data collected at 47 locations were interpreted first with curve matching techniques, using theoretically calculated master curves, in conjunction with the auxiliary curves. The initial earth
    models were second checked and reinterpreted using a 1-D inversion program (i.e., RESIX-IP in order to obtain final earth models. The final layer parameters (thicknesses and resistivities were then
    pieced together along survey lines to make electrical cross sections. Resistivity measurements show a dominant trend of decreasing resistivity (thus increasing salinity with depth and westward toward
    the Red Sea. Accordingly, three zones with different resistivity values were detected, corresponding to three different bearing formations: (i a water-bearing formation in the west containing Red Sea saltwater; (ii a transition zone of clay and clayey sand thick formation; (iii stratas saturated with fresh groundwater in the east disturbed by the presence of clay and clayey sand horizons. Deep borehole (131 m drilled in the northwestern part of the study area for groundwater investigation, has
    confirmed the findings of the resistivity survey.

  8. Drivers of population structure of the bottlenose dolphin (Tursiops truncatus) in the Eastern Mediterranean Sea

    OpenAIRE

    Genov, Tilen; Holcer, Draško; Fortuna, Caterina Maria; Gaspari, Stefania; Scheinin, A. P.; Natali, Chiara; Frantzis, Alexandros; Chelazzi, Guido; Moura, André E.

    2015-01-01

    The drivers of population differentiation in oceanic high dispersal organisms, have been crucial for research in evolutionary biology. Adaptation to different environments is commonly invoked as a driver of differentiation in the oceans, in alternative to geographic isolation. In this study, we investigate the population structure and phylogeography of the bottlenose dolphin (Tursiops truncatus) in the Mediterranean Sea, using microsatellite loci and the entire mtDNA control region. By furthe...

  9. Spawning phenology and geography of Aleutian Islands and eastern Bering Sea Pacific cod (Gadus macrocephalus)

    Science.gov (United States)

    Neidetcher, Sandra K.; Hurst, Thomas P.; Ciannelli, Lorenzo; Logerwell, Elizabeth A.

    2014-11-01

    Pacific cod (Gadus macrocephalus) is an economically and ecologically important species in the southeastern Bering Sea and Aleutian Islands, yet little is known about the spawning dynamics of Pacific cod in these regions. To address this knowledge gap, we applied a gross anatomical maturity key for Pacific cod to describe temporal and spatial patterns of reproductive status over three winter spawning seasons: 2005, 2006, and 2007. Maturity status of female Pacific cod was assessed by fishery observers during sampling of commercial catches and used to construct maps showing spawning activity in the Bering Sea and Aleutian Islands. Most spawning activity was observed on the Bering Sea shelf and Aleutian Island plateaus between 100 and 200 m depth. Data for those days when a high percentage of spawning stage fish were observed were used to identify areas with concentrations of spawning fish. Spawning concentrations were identified north of Unimak Island, in the vicinity of the Pribilof Islands, at the shelf break near Zhemchug Canyon, and adjacent to islands in the central and western Aleutian Islands along the continental shelf. The spawning season was found to begin in the last days of February or early March and extend through early to mid-April. Variation in spawning time (averaging ~10 days between years) may have been associated with a change from warm (2005) to cold (2007) climate conditions during the study period. Our information on Pacific cod spawning patterns will help inform fishery management decisions, models of spawning and larval dispersal and the spatial structure of the stock.

  10. Heterotrophic bacterial growth and substrate utilization in the oligotrophic Eastern Mediterranean (Aegean Sea

    Directory of Open Access Journals (Sweden)

    U. CHRISTAKI

    2003-06-01

    Full Text Available Heterotrophic bacterial growth and substrate utilization were studied in March and September of 1997 in the oligotrophic Aegean Sea. Maximum velocities of ectoproteolytic activity (ectoaminopeptidase ctivity, EAP, as well as amino acid assimilation and respiration rates (AA-A, AA-R were measured along with bacterial production (protein synthesis. At the northern stations which are influenced by the input of the Black Sea waters, rates at 5 m depth of EAP, AA-A and bacterial production were 2 to 3 times higher than at southern stations. Influenced by the Black Sea water, mean bacterial numbers in the 0-100 m layer showed typical oceanic concentrations averaging 0.7 x 10 6 cells ml -1 . These values, along with low bacterial production rates (30 ng C l -1 h -1 implied slow growth for bacteria and/or that a large number among them were inactive. Neither bacterial abundance nor production were correlated with primary production. The percentage of amino acids respired was higher in September compared to March, particularly in the northern Aegean (mean 69 %. The enzyme kinetic analysis showed a biphasic model, the transition between the high and low affinity enzymes being obtained at 50 ΜM. Ectoaminopeptidase activity was weakly correlated with bacterial production (p < 0.05, but strongly correlated with respiration rates of amino acids (p < 0.001, suggesting that the substrate used was devoted to maintain energy requirements.

  11. Sea-ice retreat controls timing of summer plankton blooms in the Eastern Arctic Ocean

    Science.gov (United States)

    Janout, Markus A.; Hölemann, Jens; Waite, Anya M.; Krumpen, Thomas; Appen, Wilken-Jon; Martynov, Fedor

    2016-12-01

    Two full-year mooring records of sea-ice, physical, and bio-optical parameters illuminate tight temporal coupling between the retreating seasonal ice edge and the summer phytoplankton bloom on the Laptev Sea shelf. Our records showed no sign of pelagic under-ice blooms despite available nutrients and thinning sea ice in early summer, presumably because stratification had not yet developed. Chlorophyll blooms were detected immediately after the ice retreated in late May 2014 and late July 2015. Despite radically different timing, the blooms were similar in both magnitude and length, interpreted as community-level nutrient limitation. Acoustic backscatter records suggest the delayed 2015 bloom resulted in lower zooplankton abundance, perhaps due to a timing mismatch between ice algal and pelagic blooms and unfavorable thermal conditions. Our observations provide classical examples of ice-edge blooms and further emphasize the complexity of high-latitude shelves and the need to understand vertical mixing processes important for stratification and nutrient fluxes.

  12. Ethnobotany of medicinal plants used in Eastern Mallorca (Balearic Islands, Mediterranean Sea).

    Science.gov (United States)

    Carrió, Esperança; Vallès, Joan

    2012-06-14

    This paper represents the first large-scale ethnobotanical study in the island of Mallorca, and provides significant information on pharmaceutical plant uses, built up from interviews with native people from this touristic hotspot, demonstrating its ethnopharmacological importance. To collect, analyse and evaluate the ethnobotanical knowledge concerning medicinal plants in a north-eastern Mallorcan area (municipalities of Artà, Capdepera and Son Servera; 298 km2, 31,764 inhabitants). We performed semi-structured interviews with 42 informants (mean age 77; 40% women, 60% men), identified the plant taxa reported and analysed the results, comparing them with those found in the current Mallorcan ethnobotanical information and in other territories. The informants reported data on 121 human medicinal plants representing 64 botanical families. Around 45 medicinal uses reported, concerning 37 species, have not or have very rarely been cited as medicinal. An index of medicinal importance is proposed. All efforts addressed to compiling ethnobotanical information in industrialised or touristised areas such as Eastern Mallorca are still valuable. New possibilities can be explored to give practical value to Mallorcan ethnobotanical data in the frame of considering traditional plant knowledge as part of the islanders’ lifestyle and healthy habits.

  13. Environmental policy in the north-eastern sector of the Black sea coast

    Science.gov (United States)

    Kosyan, Ruben; Godin, Evgenii; Kosyan, Alisa

    2015-04-01

    Active economic development of the Black Sea East coastal zone has started in the beginning of 20-th century. Those days the pebble taken from beaches was used for construction of buildings, rail and motor roads. Active consumption of pebble from the beaches and river banks had caused a sharp increase of sea shores abrasion and washout rate, number of landslides had also increased. Contemporary Caucasian shores of Black Sea are being developed under increasing man-caused load. Favorable natural conditions, their variety and uniqueness determine the exceptional role of these shores as very important recreational zone of Russian South. Waste urbanized areas, agricultural territories and National Parks are located in immediate neighborhood with the sea. Important industrial facilities and federal and international communi- cations, including major seaports are located in the shore zone. At present time major gas and oil transportation facilities are commissioned and being constructed in the area. Due to the change of geopolitical situation the Russian shoreline had significantly reduced in comparison with Soviet period, especially in most developed regions. Large resort complexes in Georgia, Crimea and Baltic area were lost. Russia had also lost many major seaports that, under conditions of structural change of economy and export growth, had caused the necessity of building new industrial facilities in the Black Sea coastal zone, and, consequently, had stimulated active human invasion into natural coastal processes. At the time being, a major part (three hundred nine kilometers) of Black Sea coast within Russian sector is subject to abrasion and landslide processes. Abrasion process and beaches wash-out, landslides cause destruction of industrial and transport facilities, living and public buildings, resort complexes and valuable agricultural areas. In this light, the challenge of estimation of effective methods of shores protection against wave-induced erosion

  14. Estimation of past sea-level variations based on ground-penetrating radar mapping of beach-ridges - preliminary results from Feddet, Faxe Bay, eastern Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B

    2011-01-01

    Estimates of past sea-level variations based on different methods and techniques have been presented in a range of studies, including interpretation of beach ridge characteristics. In Denmark, Holocene beach ridge plains have been formed during the last c. 7700 years, a period characterised by both...... isostatic uplift and changes in eustatic sea-level, and therefore represent an archive of past relative sea-level variations. Here, we present preliminary results from investigation of beach ridges from Feddet, a small peninsula located in Faxe Bay (Baltic Sea) in the eastern part of Denmark. Feddet has...... peninsula. Furthermore, topography along the profile lines, primary on beach ridge summits and swale bases, was measured to be included in the interpretation of the GPR reflection data using a high-resolution GPS system. The topography-corrected GPR data allow us to interpret internal sedimentary...

  15. In situ profiling of eastern Arabian Sea coastal waters using a new autonomous vertical profiler

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; Madhan, R.; Dabholkar, N.A.; Prabhudesai, S.P.; Navelkar, G.S.; Mascarenhas, A.A.M.Q.; Afzulpurkar, S.; Phaldesai, M.; Maurya, P.

    and execute dives at programmed intervals as before, but now as a fully autonomous platform. The inherent buoyancy is of prac- tical use during deployment at sea, as it enables the user to see the AVP float away from the proximity of the ship. In contrast... by oceanographers in profiling the water column is the well-known rosette con- ductivity–temperature–depth (CTD) system which is lowered toward the seabed from a ship’s winch. Portable CTD logging instruments are now available for use from small boats...

  16. Diverse methane concentrations in anoxic brines and underlying sediments, eastern Mediterranean Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.

    in the overlying water (2}3nM). De Lange et al. (1990) observed a double-layered brine in this basin: the upper brine (from 3278 to 3425m) 2002 S.M. Karisiddaiah / Deep-Sea Research I 47 (2000) 1999}2008 Fig. 2. Vertical pro"les of dissolved oxygen (O 2 in l... for constructive, thought provoking and valuable suggestions. This is N.I.O.’s contribution No. 3533. References Blanc, G., Boulegue, J., Charlou, J.L., 1990. Pro"les d’hydrocarbures legers dans l’eau de mer, les saumures et les eaux interstielles de la fosse...

  17. Genetic identification of a rare record of Ommastrephes Bartramii (Cephalopoda: Ommastrephidae) from the Eastern Adriatic Sea.

    Science.gov (United States)

    Franjević, Damjan; Skaramuca, Daria; Katavić, Vedran; Rajević, Nives; Skaramuca, Boško

    2015-01-01

    The neon flying squid Ommastrephes bartramii Lesueur, 1821 belongs to the Ommastrephidae, Cephalopoda family. The family Ommastrephidae (Mollusca: Cephalopoda) includes many commercially important species, dispersed around the world. The Ommastrephidae family is conventionally divided into three subfamilies (Illicinae, Todarodinae, and Ommastrephinae). We report a specimen of neon flying squid caught in the winter 2013 at Luka Šipanska, Island of Šipan, Croatia and identified at the genetic level using the standard mitochondrial COI barcode region. This record represents the first genetic identification of a neon flying squid from the Adriatic Sea.

  18. Origin of crude oils in the Jinhu Depression of North Jiangsu-South Yellow Sea Basin, eastern China

    Energy Technology Data Exchange (ETDEWEB)

    Xiongqi Pang; Zhijun Jin; Zhenglong Xu [Petroleum University (Beijing) (China). Key Laboratories for Petroleum Formation Mechanisms, Chinese Ministry of Education; Maowen Li [Geological Survey of Canada, Calgary, AB (Canada); Sumei Li [Petroleum University (Beijing) (China). Key Laboratories for Petroleum Formation Mechanisms, Chinese Ministry of Education; Geological Survey of Canada, Calgary, AB (Canada); Anding Chen [SINOPEC Jiangsu Oilfield Company, Jiangsu (China)

    2003-04-01

    The chemical compositions of 20 crude oils and the extracts of potential source rocks from the Jinhu Depression of the North Jiangsu-South Yellow Sea Basin, eastern China were studied in detail by geochemical methods in order to understand their genetic relationship. The oil samples were collected from the major producing fields in the Western Slope (WS) and the Biandong-Yangjiaba-Minqiao uplift belt (BMY). The rock samples studied, selected after Rock-Eval pyrolysis screening of a large suite of samples, consist of 20 shale samples in the E{sub 2}f{sub 2} member of the Paleocene Funing Formation from the oilfield areas (WS and BMY) and the Sanhe sag all within the Jinhu Depression. Geochemical characteristics indicate only one single family of oils. A number of biomarker features support deposition of the source rocks for these oils under conditions of enhanced salinity/stratified water columns. A wide thermal maturity range for the oils as indicated by sterane isomerization ratios was not substantiated by other maturity parameters. The genetic relationships between the oils and the E{sub 2}f{sub 2} member of the Paleocene Funing Formation present in the deeper parts of the Sanhe and Longgang sags were suggested using a wide range of molecular parameters. Variation in the sterane concentrations in source rocks with different maturity suggests that migrational contamination and/or in-situ extractions of organic matter from caprocks or intra-reservoir shales by mature oils could potentially produce oils with apparent immaturity at the molecular level. Secondary alteration (e.g. biodegradation) of oils in the reservoir could also have a similar effect on the bulk oil compositions. Although we do not discount the possible presence of minor amounts of 'immature oils', exploration focus in the Jinhu Depression, as well as many other rift basins in eastern China, should be on mature oils derived from the deep source kitchens. (author)

  19. Vegetation Analysis in the Red Sea-Eastern Desert Ecotone at the Area between Safaga and South Qusseir, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed G. Sheded

    2014-12-01

    Full Text Available The current work is concerned with the studying the impact of environmental conditions on the vegetation in the arid ecotone located between Red Sea and Eastern Desert from Safaga to south Qusseir. Ninety eight quadrats inside 13 transects were selected to cover the environmental gradient across the ecotone, from the coastal region to the boundary of Eastern Desert. Forty five species were recorded belonged to 24 different families and 38 genera. The perennial species were 38 while the annuals were seven species. Zygophyllum coccineum had the highest presence value (89.8% followed by Tamarix nilotica (56.1% and Zilla spinosa (51.02%. Chamaephytes and Hemicryptophytes were the most prevailed life-forms. Chrological analysis exhibited that SaharoSindian and Sahro-Sindian with its extension to Sudano-Zambezian elements were the most dominant. TWINSPAN classification technique produced three vegetation groups include nine clusters at the fourth level. These groups identified according to the first and second dominant species as follows: Convolvulus hystrix - Panicum turgidum, Tamarix aphylla - Limonium pruinosum and Nitraria retusa - Tamarix nilotica. DECORANA results indicated a reasonable segregation among these groups along the ordination axis 1 and 2. Vegetation analysis showed that ecotonal clusters have highest number of species/cluster, high species richness and high species turnover. Therefore, the largest group existed in the ecotone (34 species while the desert group contained eight species and the coastal group included three species. Among the estimated soil variables in this study, pH, coarse sand, HCO3-, SO42- , clay and PO43- have the highest effect on species distribution. Sodium adsorption ratio (SAR was the effective factor in detecting the ecotonal species, Aeluropus lagopoides and Limonium pruinosum.

  20. Geochemical characteristics of late Quaternary sediments from the southern Aegean Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    A. SIOULAS

    2000-12-01

    Full Text Available Ten cores from the southern Aegean Sea have been logged for their lithological composition and seventy-three sub-samples were analysed for the determination of major and trace elements concentrations. Four lithological units were identified, namely, mud, volcanic, turbidite and sapropel. On the basis of the “Z-2” Minoan ash layer radiocarbon age sedimentation rates for the southern Aegean Sea were estimated at 3.26 to 4.15 cm kyr -1. Simple correlation analysis revealed three groups of elements associated with: (1 biogenic carbonates; (2 terrigenous alumino-silicates and (3 sapropelic layers. R-mode factor analysis applied on the carbonate-free corrected data-set defined four significant factors: (1 the “detrital alumino-silicate factor” represented by Si, Al, Na, K, Rb, Zr, Pb and inversely related to Ca, Mg, and Sr; (2 a “hydrothermal factor” loaded with Cr, Ni, Co, Cu, Fe; (3 the “volcanic ash factor” with high loadings for Ti, Al, Fe, Na and (4 a “sapropel factor” represented by Ba, Mo, and Zn. High factor scores for the “hydrothermal factor” were observed in sediment samples proximal to Nisyros Isl., suggesting a potential hydrothermal influence. Red-brown oxides and crusts dredged from this area support further this possibility. The use of factor analysis enabled for a better understanding of the chemical elements associations that remained obscured by correlation analysis.

  1. The Temporal Dynamics of Coastal Phytoplankton and Bacterioplankton in the Eastern Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Ofrat Raveh

    Full Text Available This study considers variability in phytoplankton and heterotrophic bacterial abundances and production rates, in one of the most oligotrophic marine regions in the world-the Levantine Basin. The temporal dynamics of these planktonic groups were studied in the coastal waters of the southeastern Mediterranean Sea approximately every two weeks for a total of two years. Heterotrophic bacteria were abundant mostly during late summer and midwinter, and were positively correlated with bacterial production and with N2 fixation. Based on size fractionating, picophytoplankton was abundant during the summer, whereas nano-microphytoplankton predominated during the winter and early spring, which were also evident in the size-fractionated primary production rates. Autotrophic abundance and production correlated negatively with temperature, but did not correlate with inorganic nutrients. Furthermore, a comparison of our results with results from the open Levantine Basin demonstrates that autotrophic and heterotrophic production, as well as N2 fixation rates, are considerably higher in the coastal habitat than in the open sea, while nutrient levels or cell abundance are not different. These findings have important ecological implications for food web dynamics and for biological carbon sequestration in this understudied region.

  2. Investigation of environmental radioactivity in waste dumping areas of the far eastern seas. JAERI`s activities in the 1st Japanese-Korean-Russian joint expedition 1994

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Hikaru; Matsunaga, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yabuuchi, Noriaki

    1996-10-01

    Large quantities of radioactive waste have been dumped in the Far Eastern Sea by the former USSR and Russia. In order to survey marine radioactive contamination in the Far Eastern Sea, the first Japanese-Korean-Russian joint expedition was conducted according to the governmental agreement. The joint expedition was conducted at the areas of the Russian radioactive waste dumping site from March 18 1994 to April 6, 1994. JAERI participated in this expedition according to the request from STA Japan, and conducted mainly on-board measurement of marine radioactivities. The results showed that the radionuclides concentrations in seawater and seabed sediment samples from the study site were not different from those in the western North Pacific. This report summarises JAERI`s activities in the expedition. Final report by Japanese-Korean-Russian government and IAEA is annexed. (author)

  3. Marine bird sighting and other data from aircraft in the Eastern Chukchi Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 July 1978 to 20 August 1978 (NODC Accession 8200032)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from aircraft in the Eastern Chukchi Sea from 25 July 1978 to 20 August 1978. Data were collected by the...

  4. AFSC/RACE/EcoFOCI: NPRB project number 926: Assessing the condition of walleye pollock, Theragra chalcogramma, larvae in the eastern Bering Sea with muscle-based flow cytometry cell cycle analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Walleye pollock are an important component of the eastern Bering Sea ecosystem due to their vast numbers and biomass and are of great commercial importance. Their...

  5. Hydrological, plankton and pigment observations in the Makassar Strait, Madura Strait and Eastern Java Sea by the R.V. Samudera, April 16 to May 19, 1975 (NODC Accession 7700306)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and chemical data were collected using net and bottle casts from the R.V. SAMUDERA in the Makassar Strait, Madura Strait and Eastern Java Sea from 16...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    A. J. Boris

    2016-01-01

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

  8. Variations in fault-slip data and cooling history reveal corridor of heterogeneous backarc extension in the eastern Aegean Sea region

    Science.gov (United States)

    Ring, Uwe; Gessner, Klaus; Thomson, Stuart

    2017-03-01

    We report fault-slip data across the boundary between the highly extended and largely submerged crust underlying the Aegean Sea from Samos in the north to eastern Crete in the south, and the much less extended and emergent crust of western Anatolia. We identify three brittle deformation increments, a late Miocene (mainly Pliocene) to Recent crustal stretching increment, an intermittent early to late Miocene shortening increment concurrent with extension and magmatism, and a Miocene extensional event. The youngest increment documents late Miocene to Recent NNE extension over large areas, but can locally also be oriented SE (Amorgos and Astipalea Islands), and ESE (eastern Crete) suggesting overall oblate strain geometry. The intermittent Miocene ( 24-5 Ma) fault-slip records suggest overall prolate strain geometry, where NNE stretching is accompanied by E-W shortening. The older extension event is mainly NNE directed but on Samos Island extension is E-W, probably reflecting local extension in a sinistral wrench corridor in the early/mid Miocene. Overall it seems that since the early Miocene NNE-trending extension is the dominant regime in the eastern Aegean with an intermittent component of short-lived E-W shortening. The existence of a corridor of heterogeneous crustal deformation - which is spatially associated with uncharacteristically old fission track ages - and the apparent change in strain geometry in time challenge concepts that propose that the eastern Aegean Sea and western Anatolia have been deformed as a continuous tectonic domain since the Miocene. We propose that the regional variation in extensional strain geometry resulted from a sinistral wrench component that was superimposed on the regional 'background' NNE extension by translation across a diffuse plate boundary. We conclude that the eastern shoreline of the Aegean Sea is controlled by a Miocene to Recent sinistral wrench corridor that accommodated movement between different lithospheric domains.

  9. Postglacial sedimentary regime around northern Sylt, South-eastern North Sea, based on shallow seismic evidence

    DEFF Research Database (Denmark)

    Boldreel, Lars Ole; Kuijpers, Antoon; Madsen, Emil B

    2010-01-01

    by the presence of minor dunes, indicative of flood-current control, apart from a central zone where ebb-tide is responsible for northward-directed sediment transport. Sparker seismic and Chirp III data are consistent with processes having been persistent throughout the Holocene. Based on the study a model......-shore (tidal) currents heading towards the Lister Tief. The southern part of Lister Tief is characterized by the presence of a major dune field with up to 8 m high compound dunes with wavelengths up to 350 m indicative of easterly-directed sediment transport (flood dominated). Further to the northwest......During the past 5 years the coastal zone offshore the northern part of the island of Sylt, has been investigated by sparker seismics and high-resolution subbottom profiling. The North Sea sector of the area is characterized by northward-directed sediment bypass as a result of strong long...

  10. Lucinoma kazani n. sp. (Mollusca: Bivalvia): evidence of a living benthic community associated with a cold seep in the Eastern Mediterranean Sea

    Science.gov (United States)

    Salas, C.; Woodside, J.

    2002-06-01

    Lucinoma kazani, a new deep-water species of Lucinidae from the Eastern Mediterranean Basin, is described and illustrated. The material was collected in the Anaximander Mountains, between Rhodes and Cyprus, Eastern Mediterranean. The first living specimens were collected during the Dutch ANAXIPROBE project in the Kazan volcano, at a depth of 1709 m. Later, during the MEDINAUT programme, both living specimens and shells were collected from several mud volcanoes at different depths in the Anaximander Mountains. This bivalve holds symbionts in the ctenidia, as do all previously studied Lucinidae. The type of habitat of this new species is gas-saturated mud, with high levels of methane, which diffuses upwards into a low-oxygen deep-water. Therefore, we consider this as evidence of a living cold seep community in the Eastern Mediterranean Sea.

  11. 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.

  12. Discards of the commercial boat seine fisheries on Posidonia oceanica beds in the eastern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Perica Cetinić

    2011-06-01

    Full Text Available Scientific observer records were used to estimate the retained and discarded catch composition of the commercial boat seine fisheries over Posidonia oceanica (Linnaeus Delile meadows in the eastern Adriatic, from November 2008 to December 2009. A total of 91 fish and cephalopod species were recorded in the catches, of which 20 species were always retained, 40 were always discarded and the remaining 31 were selected depending on size (only larger specimens were retained. The most abundant species in the retained catch were Spicara smaris, Atherina hepsetus and Mullus barbatus, while Chromis chromis, Symphodus ocellatus and small specimens of Boops boops dominated the discards. An estimated 43.5% by number and 28.5% by weight of the total catch were discarded. Since the minimum landing size (MLS is regulated for only 4 out of the 15 most important species in this study, and even these regulations are only partially followed, discarding practices were generally market-driven. The retained and discarded amounts of the catch as well as the numbers of retained and discarded species showed a seasonal pattern. The catches recorded during summer/autumn were generally larger than those in winter/spring. High rates of immature specimens were observed for the most important species, which is probably related to the role of Posidonia beds as important nursery grounds.

  13. Methanogenic diversity and activity in hypersaline sediments of the centre of the Napoli mud volcano, Eastern Mediterranean Sea.

    Science.gov (United States)

    Lazar, Cassandre Sara; Parkes, R John; Cragg, Barry A; L'Haridon, Stéphane; Toffin, Laurent

    2011-08-01

    Submarine mud volcanoes are a significant source of methane to the atmosphere. The Napoli mud volcano, situated in the brine-impacted Olimpi Area of the Eastern Mediterranean Sea, emits mainly biogenic methane particularly at the centre of the mud volcano. Temperature gradients support the suggestion that Napoli is a cold mud volcano with moderate fluid flow rates. Biogeochemical and molecular genetic analyses were carried out to assess the methanogenic activity rates, pathways and diversity in the hypersaline sediments of the centre of the Napoli mud volcano. Methylotrophic methanogenesis was the only significant methanogenic pathway in the shallow sediments (0-40 cm) but was also measured throughout the sediment core, confirming that methylotrophic methanogens could be well adapted to hypersaline environments. Hydrogenotrophic methanogenesis was the dominant pathway below 50 cm; however, low rates of acetoclastic methanogenesis were also present, even in sediment layers with the highest salinity, showing that these methanogens can thrive in this extreme environment. PCR-DGGE and methyl coenzyme M reductase gene libraries detected sequences affiliated with anaerobic methanotrophs (mainly ANME-1) as well as Methanococcoides methanogens. Results show that the hypersaline conditions in the centre of the Napoli mud volcano influence active biogenic methane fluxes and methanogenic/methylotrophic diversity. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  14. Modeled connectivity between northern rock sole (Lepidopsetta polyxystra) spawning and nursery areas in the eastern Bering Sea

    Science.gov (United States)

    Cooper, D. W.; Duffy-Anderson, J. T.; Stockhausen, W. T.; Cheng, W.

    2013-11-01

    Connectivity between spawning and potential nursery areas of northern rock sole, Lepidopsetta polyxystra, in the eastern Bering Sea was examined using an individual-based biophysical-coupled model. Presumed spawning areas were identified using historical field-collected ichthyoplankton data, and nursery habitats were characterized based on previously described settlement areas. Simulated larvae were released from spawning areas near the Pribilof Islands, south of the Pribilof Islands along the outer continental shelf, on the north side of the Alaska Peninsula, and in the Gulf of Alaska south of Unimak Island. Simulated larvae were transported along two general pathways: 1) northwards along the outer continental shelf from Unimak Island towards the Pribilof Islands and further north offshore of mainland Alaska, and 2) eastward along the Alaska Peninsula. At the end of the 2-month simulation, drift pathways placed pre-settlement stage larvae offshore of known nursery areas of older juveniles near mainland Alaska, consistent with a hypothesis that initial settlement may be followed by substantial post-settlement redistribution.

  15. Fish community structure on littoral rocky shores in the Eastern Aegean Sea: Effects of exposure and substratum

    Science.gov (United States)

    De Raedemaecker, Fien; Miliou, Anastasia; Perkins, Rupert

    2010-11-01

    Littoral rocky shores are important habitats for many coastal fish species providing food, shelter and nursery grounds. Nearshore fish community structure results have been mainly derived from macro-scale habitat characteristics including depth and wave exposure but the influence of, and interaction with, micro-scale habitat substratum features is not well known. This study investigated the structure and functioning of the ichthyofauna composition on rocky substrata around the island of Arki in the Eastern Aegean Sea. Quantitative surveys of fish assemblage composition were carried out by Underwater Visual Census (UVC) at 14 sites assigned to three levels of exposure. The physical substratum of every transect area was described by 14 microhabitat characteristics. Multidimensional scaling (MDS) showed that exposure to wave activity was a significant factor in structuring fish assemblages differing in feeding guilds, species richness and diversity. Substratum heterogeneity, depth, boulder complexity and verticality were the main substratum descriptors that were related with wave exposure and hence were the determining factors defining fish community structure, as revealed by Canonical Correspondence Analysis (CCA). The similarity of percentages (SIMPER) determined the species that typified the different exposure groups. This study has shown that rocky littoral shores are of high ecological importance and their conservation is of great significance to maintain coastal fish diversity.

  16. Seasonal and spatial variations of marine litter on the south-eastern Black Sea coast.

    Science.gov (United States)

    Terzi, Yahya; Seyhan, Kadir

    2017-07-15

    The south-eastern Black Sea coast in Turkey was evaluated for marine litter composition and density covering nine beaches during four seasons. The marine litter (>2cm in size), was collected from the coast and categorized into material and usage categories. The data analysis showed that plastic was the most abundant litter (≥61.65%) by count and weight followed by styrofoam and fabric. The marine litter density ranged from 0.03 to 0.58 with a mean (±SD) of 0.16±0.02 items/m 2 by count. Based on weight, it varied between 0.44 and 14.74g/m 2 with 3.35±1.63. The east side had a higher marine litter density than the west side with significant differences between beaches. The variations due to different seasons were not significant for any beach. The results of this study should provide baseline information about the coastal marine pollution and will assist the mitigation strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Alterations in microbial community composition with increasing fCO2: a mesocosm study in the eastern Baltic Sea

    Science.gov (United States)

    Crawfurd, Katharine J.; Alvarez-Fernandez, Santiago; Mojica, Kristina D. A.; Riebesell, Ulf; Brussaard, Corina P. D.

    2017-08-01

    Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( cell diameter) showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.

  18. Influence of the tidal front on the three-dimensional distribution of spring phytoplankton community in the eastern Yellow Sea.

    Science.gov (United States)

    Choi, Byoung-Ju; Lee, Jung A; Choi, Jae-Sung; Park, Jong-Gyu; Lee, Sang-Ho; Yih, Wonho

    2017-04-01

    Hydrographic observation and biological samplings were conducted to assess the distribution of phytoplankton community over the sloping shelf of the eastern Yellow Sea in May 2012. The concentration of chlorophyll a was determined and phytoplankton was microscopically examined to conduct quantitative and cluster analyses. A cluster analysis of the phytoplankton species and abundance along four observation lines revealed the three-dimensional structure of the phytoplankton community distribution: the coastal group in the mixed region, the offshore upper layer group preferring stable water column, and the offshore lower layer group. The subsurface maximum of phytoplankton abundance and chlorophyll a concentration appeared as far as 64 km away from the tidal front through the middle layer intrusion. The phytoplankton abundance was high in the shore side of tidal front during the spring tide. The phytoplankton abundance was relatively high at 10-m depth in the mixed region while the concentration of chlorophyll a was high below the depth. The disparity between the profiles of the phytoplankton abundance and the chlorophyll a concentration in the mixed region was related to the depth-dependent species change accompanied by size-fraction of the phytoplankton community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Alterations in microbial community composition with increasing fCO2: a mesocosm study in the eastern Baltic Sea

    Directory of Open Access Journals (Sweden)

    K. J. Crawfurd

    2017-08-01

    Full Text Available Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2 by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( <  20 µm cell diameter showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2. Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.

  20. First record of Aequorea macrodactyla (Cnidaria, Hydrozoa from the Israeli coast of the eastern Mediterranean Sea, an alien species indicating invasive pathways

    Directory of Open Access Journals (Sweden)

    Gur Mizrahi

    2015-07-01

    Full Text Available The species of Aequorea attract much scientific interest as they contain the unique Green Fluorescent Protein (GFP. In this work we describe for the first time the discovery of a hydrozoan jellyfish belonging to the genus Aequorea from the Israeli eastern Mediterranean that contains and exhibits fluorescent protein. Finding Aequorea macrodactyla (Brandt, 1835 in the eastern Mediterranean indicates that changes are occurring in the gelatinous fauna of this area. This hydromedusa is known in the seas adjoining the Mediterranean though most of its records are more than four decades old. We examined and identified the newly discovered Israeli Aequorea species by combining two phylogenetic systems, traditional morphological phylogeny and molecular phylogenetics. The molecular identification determined that the species is A. macrodactyla but with minor genetic differences in the mtDNA 16S gene marker. A 1% difference between the Israeli and the Japanese A. macrodactyla was demonstrated, which suggests that the genetic difference between the Israeli and the Japanese population is small but existent. Invasive pathways for this jellyfish were examined by phylogenetic and taxonomic relationships with similar Cnidaria. The results indicate introduction from the Indo-Pacific as invasive pathway, probably by human transportation, and the discovery of A. macrodactyla in the eastern Mediterranean Sea could be interpreted as part of the changes in marine biota as a result of cumulative effects of anthropogenic and global changes that affect the eastern Mediterranean basin.

  1. Heat loss in air of an Antarctic marine mammal, the Weddell seal.

    Science.gov (United States)

    Mellish, Jo-Ann; Hindle, Allyson; Skinner, John; Horning, Markus

    2015-01-01

    The conflicting needs of homeostasis in air versus water complicate our understanding of thermoregulation in marine mammals. Large-scale modeling efforts directed at predicting the energetic impact of changing sea ice conditions on polar ecosystems require a better understanding of thermoregulation in air of free-ranging animals. We utilized infrared imaging as an indirect approach to determine surface temperatures of dry, hauled-out Weddell seals (Leptonychotes weddellii, n = 35) of varying age and body condition during the Antarctic summer. The study groups provided a fivefold range in body mass and a threefold range in blubber depth. Surface temperature (T s) did not vary by body region (head, shoulder, axilla, torso, hip, flippers). Average seal T s (mean 13.9 ± 11.2 °C) was best described through a combination of the physical traits of body mass and environmental variables of ambient temperature T air, and wind speed. Additional factors of ice temperature (T ice), relative humidity and cloud cover did not improve the model. Heat transfer model estimates suggested that radiation contributed 56.6 ± 7.7 % of total heat loss. Convection and conduction accounted for the remaining 15.7 ± 12.3 and 27.7 ± 9.3 %, respectively. Heat loss by radiation was primarily influenced by body mass and wind speed, whereas convective heat loss was influenced primarily by blubber depth and wind speed. Conductive heat loss was modeled largely as a function of physical traits of mass and blubber depth rather than any environmental covariates, and therefore was substantially higher in animals in leaner condition.

  2. Vertical nutrient fluxes, turbulence and the distribution of chlorophyll a in the north-eastern North Sea

    Science.gov (United States)

    Bendtsen, Jørgen; Richardson, Katherine

    2017-04-01

    During summer the northern North Sea is characterized by nutrient rich bottom water masses and nutrient poor surface layers. This explains the distribution of chlorophyll a in the water column where a subsurface maximum, referred to as the deep chlorophyll maximum (DCM), often is present during the growth season. Vertical transport of nutrients between bottom water masses and the well lit surface layer stimulates phytoplankton growth and this generally explains the location of the DCM. However, a more specific understanding of the interplay between vertical transports, nutrient fluxes and phytoplankton abundance is required for identifying the nature of the vertical transport processes, e.g the role of advection versus vertical turbulent diffusion or the role of localized mixing associated with mesoscale eddies. We present results from the VERMIX study in the north-eastern North Sea where nutrients, chlorophyll a and turbulence profiles were measured along five north-south directed transects in July 2016. A high-resolution sampling program, with horizontal distances of 1-10 km between CTD-stations, resolved the horizontal gradients of chlorophyll a across the steep bottom slope from the relatively shallow central North Sea ( 50-80 m) towards the deep Norwegian Trench (>700 m). Low oxygen concentrations in the bottom water masses above the slope indicated enhanced biological production where vertical mixing would stimulate phytoplankton growth around the DCM. Measurements of variable fluorescence (Fv/Fm) showed elevated values in the DCM which demonstrates a higher potential for electron transport in the Photosystem II in the phytoplankton cells, i.e. an indication of nutrient-rich conditions favorable for phytoplankton production. Profiles of the vertical shear and microstructure of temperature and salinity were measured by a VMP-250 turbulence profiler and the vertical diffusion of nutrients was calculated from the estimated vertical turbulent diffusivity and the

  3. Spatial variations of bacterial communities and related biogeochemical activity of cold seep sites in the Eastern Mediterranean deep sea

    Science.gov (United States)

    Pop Ristova, P.; Felden, J.; Wenzhöfer, F.; Ramette, A.; Boetius, A.

    2012-04-01

    Cold seeps ecosystems, characterized by emissions of the potential greenhouse gas methane, and often associated with vast repositories of gas hydrates, represent patchy and isolated deep-sea oases of life. They host highly dynamic habitats that are spatially fragmented and temporarily variable. Microorganisms mediate all major geochemical processes at cold seeps i.e. anaerobic oxidation of methane and sulphide oxidation, which in turn enables high biomasses and biodiversity of chemosynthetic organisms to be sustained. Cold seeps are also characterized by high habitat heterogeneity and by dynamic geological, geochemical and biogenic processes influencing seep biodiversity. The deep Eastern Mediterranean sea, encompassing numerous geologically different cold seep sites, offers a unique opportunity for the study of habitat heterogeneity and effects on microbial communities at various spatial scales in relation to their biogeochemical environment. A combined approach, using molecular (ARISA and 454 pyrosequencing) and geochemical techniques (porewater analysis, ex situ radiotracer incubations and in situ quantifications of methane, oxygen and sulphide fluxes), was applied to investigate the biogeochemical activity and related bacterial diversity of hydrate-bearing seep-habitats. Here we present data on the comparison on large (> 100 km) and small (0.01 - 100 m) spatial scales, i.e. between and within different cold seep ecosystems, such as the Amon mud volcano, the Amsterdam mud volcano and the Central Pockmark area. Methane effluxes, sediment AOM rates and total oxygen uptake differed by an order of magnitude among habitats within a single cold seep structure, indicating high sediment heterogeneity on small (100 m) spatial scales. Conversely, similar geochemical conditions prevailed at seep-habitats separated by hundreds of kilometers. The bacterial community structures followed similar patterns, and highest variations could be detected at cold seeps with contrasting

  4. Seafloor morphology: nature of the seabed and the cold water corals of the Levante Canyon (eastern Ligurian Sea, NW Mediterranean)

    Science.gov (United States)

    Delbono, Ivana; Ivaldi, Roberta; Pratellesi, Marta; Fanelli, Emanuela; Peirano, Andrea; Cocito, Silvia; Dialti, Lorenzo; Delfanti, Roberta

    2014-05-01

    The Levante Canyon, located approximately in the offshore area of Cinque Terre (eastern Ligurian Sea, NW Mediterranean), was investigated in autumn 2013 onboard Italian Navy Ships through high resolution multibeam (MB), side scan sonar (SSS) and image data acquired by a Remotely Operating Vehicle (ROV) in order to study the seafloor features and ecological characters. First data allow us to product a seabed mapping of the study area with high detail of seafloor shapes, to be extended to other similar sectors of the canyon catchment area, constituted by a dendritic pattern of each individual gully network. The highest values of slope (17°) can be found in the steep canyon heads and flanks. Slope values up to 10° can be seen depicting sea-bed mounds on the northernmost and central interfluve. MB and SSS data show higher acoustic backscatter in the deepest sections of the canyon than interfluve and the changes in the sea-bed nature over the mounds are highlighted as areas of variable intensity. ROV images were recorded from 510 m depth up to 370 m and suggested the presence of biological communities, mainly typical of deep muddy bottom, and small cold water coral colonies, possibly identified as Madrepora oculata. This survey provides not only a detailed mapping of the variable morphology of the proximal area of the Levante Canyon, but it also investigates the seabed nature and biological communities within the canyon system for the assessment of a potential Site of Community Importance (SCI) under the European Commission Habitats Directive (92/43/EEC). In particular cold water corals (CWC) provide a complex structural marine habitat hosting high levels of biological diversity, which are in the reef habitat three times higher compared to the surrounding seabed. For this reason they fall within the habitats that deserve protection (EU-Habitat 1170 "Reefs"). Preliminary observations and data interpretations suggest that the Levante Canyon shows interesting

  5. Spatial distribution of sardine and anchovy early life stages along the eastern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Barbara Zorica

    2015-10-01

    Full Text Available Despite long-term investigations of the Adriatic Sea in general and extensive research on sardine and anchovy as ecologically and economically important fish species, knowledge concerning their spawning ecology, precisely their possible spawning grounds, is still incomplete. Therefore, two scientific surveys (January, July 2012 were performed, as target species spawn during different periods of the year (sardine - October to April (Sinovčić et al., 2007 and anchovy - April to September (Zorica et al., 2013. Throughout these surveys, standard vertical plankton tows were made during the daylight at 72 stations in January and 60 stations in July using a WP2 sampler (mouth opening, 0.255 m2; mesh size, 0.200 mm. WP2 net was put vertically down during the calm sea to a depth of 100 m or to 5 m above the seabed in relatively shallow marine area (less than 100 m. Plankton samples were preserved in 4% buffered formalin and transported to the laboratory where they were analysed. Throughout ichtyoplankton analysis of samples collected during the winter survey a total of 506 sardine eggs and 348 larvae were sorted out. The mean sardine egg and larval abundance in the analysed period at positive stations was 57.8 +/- 77.4 eggs/m2 and 29 +/- 25.85 larvae/m2, with peaks of 396 eggs/m2 and 108 larvae/m2 at positive sampling stations. Concerning the summer survey and anchovy early life stages from obtained samples 1489 anchovy eggs and 1036 larvae were isolated. Average abundance of anchovy eggs and larvae was 145.26 +/- 201.27eggs/m2 and 115.11+/- 162.32 larvae/m2, respectively. The highest values of mentioned parameters at positive stations were 800 eggs/m2 and 952 larvae/m2. According to obtained results and their processing within Ocean Data View (odv.awi.de, revile that both species during 2012 spawn above the whole continental shelf and the areas of higher early life stages abundance overlap.

  6. Environmental and climatic changes in the Baltic Sea and the eastern Mediterranean Sea : as recorded by pigments and isotopes in sediments

    OpenAIRE

    Borgendahl, Johanna

    2006-01-01

    This thesis is a study of Holocene sapropels from two semi-enclosed seas; the Baltic Sea and the Mediterranean Sea. Sapropels are sedimentary layers with organic C > 2%. The Baltic Sea and the Mediterranean Sea have a limited water exchange, and despite differences in water depth and salinity, mechanisms for fluxes and preservation of Corg are principally the same. Primary focus is on biomarkers for increased primary productivity and anoxic/euxinic bottom water. Pigments (primarily from cy...

  7. Distribution and abundance of fish larvae in the northern Ionian Sea (Eastern Mediterranean)

    Science.gov (United States)

    Granata, Antonia; Cubeta, Annaluce; Minutoli, Roberta; Bergamasco, Alessandro; Guglielmo, Letterio

    2011-09-01

    The purpose of this paper was to study the spatial distribution, abundance and composition of fish larvae in the northern Ionian Sea. Samples were collected to the 600 m depth with an electronic multinet BIONESS during the "INTERREG Italia-Grecia" oceanographic cruise carried out in March 2000 off the Apulian Italian coast. A total of 46 species of teleost early stages were collected, belonging to 38 genera and 22 families. Over 52% of the larvae identified were mesopelagic species, almost 27% were demersal and about 21% pelagic. A total of 307 myctophids, 69 clupeids and 61 gadid post-larvae dominated the community. Benthosema glaciale (mean 6.1 mm SL) was the most abundant species (21.6%), the most frequent in the samples (28.8%), and dominant in the whole study area (mean 1.4 ind/100 m3). Particular attention was given to the horizontal and vertical distribution and abundance of the three dominant post-larval species: Benthosema glaciale, Sprattus sprattus sprattus and Notoscopelus elongatus. The Pearson coefficient ( R = 0.734) showed a high correlation between total zooplankton and fish larval assemblages in terms of spatial distribution abundance values. Regarding the vertical distribution of fish larvae, Sorensen's index ( S = 0.69) showed that fish larvae and total zooplankton abundance peaks co-occurred along the water column.

  8. Surface heat fluxes and ecosystem function in the Cretan Sea (eastern Mediterranean): a modelling study

    Science.gov (United States)

    Siddorn, J. R.; Allen, J. I.

    2003-01-01

    As a component of the Mediterranean Forecast System Pilot Project, a data buoy was deployed in the Cretan Sea. A 1-D ecosystem model of the site has been used to investigate the role of surface heat fluxes in determining modelled ecosystem behaviour. The method of calculation of these fluxes, the quality of the data used, and the temporal resolution of the data all had an impact upon the modelled ecosystem function. The effects of the changes in heat flux formulation were substantial, with both annually averaged properties of the system and the seasonal evolution of the biology being affected. It was also found that the ecosystem model was extremely sensitive to the accuracy of the meteorological forcing data used, with substantial changes in biology found when offsets in the forcing data were imposed. The frequency of forcing data was relatively unimportant in determining the biological function, although lower frequency forcing damped high frequency variability in the biology. During periods of mixing the biology showed an amplified response to changes in physical dynamics, but during periods of stratification the variations in the physics were found to be less important. Zooplankton showed more sensitivity to physical variability than either phytoplankton or bacteria. The consequences for ecosystem modelling are discussed.

  9. Species identification of small pelagic fish schools by means of hydroacoustics in the Eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    K. TSAGARAKIS

    2015-01-01

    Full Text Available Reliable biomass estimates by means of hydroacoustics largely depend on the correct identification of acoustic targets. Data collected during five summer acoustic surveys (2004-2008 in the North Aegean Sea (Greece were analyzed to explore effective discrimination of small pelagic fish schools according to the species they belong. Discriminant Function Analyses (DFA using bathymetric, energetic and morphometric school descriptors as explanatory variables were applied per research cruise as well as to pooled data from all surveys. Results revealed that the schools can be successfully classified into the five species considered (anchovy Engraulis encrasicolus, sardine Sardina pilchardus, round sardinella Sardinella aurita, blue whiting Micromessistius poutassou, and Atlantic mackerel Scomber scombrus. The percentage of correct classifications in terms of number of schools was higher in the analyses of the annual cruises (75.6%-95.36% than in the analysis of pooled data (≈72%. This is because of (i the lower number of species, as well as (ii the reduced intraspecific variability, occurring in each separate cruise. Significant differences were detected among school descriptors for the different species, revealing discrete aspects of schooling behaviour for each species. The benefit of the specific approach is that the classification functions of the DFAs can be used to classify a larger set of schools, which has not been possible to assign to specific species. Overall the approach constitutes an objective, more automated and less time consuming procedure for the analysis of acoustic data and can contribute to the improvement of biomass estimates in the area.

  10. The Rough-Toothed Dolphin, Steno bredanensis, in the Eastern Mediterranean Sea: A Relict Population?

    Science.gov (United States)

    Kerem, D; Goffman, O; Elasar, M; Hadar, N; Scheinin, A; Lewis, T

    Only recently included among the cetacean species thought to regularly occur in the Mediterranean, the rough-toothed dolphin (Steno bredanensis) is an obscure and enigmatic member of this ensemble. Preliminary genetic evidence strongly indicates an Atlantic origin, yet the Mediterranean distribution for this species is conspicuously detached from the Atlantic, with all authenticated records during the last three decades being east of the Sicilian Channel and most within the bounds of the Levantine Basin. These dolphins are apparently a small, relict population, probably the remnant of a larger one, contiguous with that in the Atlantic and nowadays entrapped in the easternmost and warmest province. Abundance data are lacking for the species in the Mediterranean. Configuring acoustic detection software to recognise the apparently idiosyncratic vocalisations of rough-toothed dolphins in past and future acoustic recordings may prove useful for potential acoustic monitoring. Evidence accumulated so far, though scant, points to seasonal occupation of shallow coastal waters. Vulnerability to entanglement in gill-nets, contaminants in the region, and the occurrence of mass strandings (possibly in response to anthropogenic noise), are major conservation concerns for the population in the Mediterranean Sea. © 2016 Elsevier Ltd. All rights reserved.

  11. Use of nearshore and estuarine areas by gray whales (Eschrichtius robustus) in the eastern Bering Sea

    Science.gov (United States)

    Gill, Robert E.; Hall, John D.

    1983-01-01

    During spring aerial surveys of the coast of the southeastern Bering Sea significant numbers of gray whales were seen in nearshore waters along the north side of the Alaska Peninsula. Many (50-80%) of these animals were observed surfacing with mud trails or lying on their sides, characteristics both associated with feeding. A migration route close to shore (within 1-2 km) was used until whales neared Egegik Bay, where they began to head west 5-8 km offshore, across northern Bristol Bay. Smaller numbers of gray whales were present throughout summer in nearshore waters and estuaries along the north side of the Alaska Peninsula. At Nelson Lagoon gray whales normally used the lagoon in spring, were absent during early summer, returned in mid-summer, and then were present until late November when they departed for the wintering grounds. Gray whales were present in the lagoon most often during periods of peak tidal flow; those that appeared to be feeding were oriented into the current. Three behaviors that appeared to be associated with feeding were observed: side-feeding from a stationary position within shallow waters of lagoon channels, diving within the lagoon and in nearshore waters, and elliptical side-feeding in the surf zone along the outer coast. Large crustaceans of the genus Crangon were available to and probably eaten by gray whales at Nelson Lagoon.

  12. Radiological significance of coal, slag and fly ash samples from the Eastern Black Sea region

    Energy Technology Data Exchange (ETDEWEB)

    Damla, Nevzat [Batman Univ. (Turkey). Dept. of Physics; Cevik, Ugur [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Physics; Kara, Ayhan [Osmaniye Korkut Ata Univ. (Turkey). Dept. of Physics

    2012-11-15

    This work presents a study of natural radioactivity levels in coal and its combustion residues (fly ash and slag) used in the houses in Black Sea Region, Turkey. Coal, fly ash and slag samples were provided from different locations of the region and analyzed by gamma spectroscopy using a high-purity germanium detector (HPGe). Also, chemical analyses of these samples were carried out using energy dispersive X-ray fluorescence spectrometer. The mean {sup 226}Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg{sup -1}, respectively. The mean {sup 232}Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg{sup -1}, respectively. The mean {sup 40}K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg{sup -1}, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Ra{sub eq}), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (H{sub ex}) and internal hazard index (H{sub in}) and compared with the internationally accepted or reference values. The mean Ra{sub eq} values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg{sup -1} by the Organization for Economic Cooperation and Development (OECD). The overall mean outdoor terrestrial gamma air absorbed dose rate in coal, fly ash and slag samples are 119, 129 and 62 nGy h{sup -1} and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y{sup -1}, which is higher than the worldwide average (0.07 mSv y{sup -1}), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for {sup 226}Ra and {sup 232}Th were found 1.14 and 1.01, respectively. (orig.)

  13. Contrasting reproductive strategies in three deep-sea octocorals from eastern Canada: Primnoa resedaeformis, Keratoisis ornata, and Anthomastus grandiflorus

    Science.gov (United States)

    Mercier, A.; Hamel, J.-F.

    2011-06-01

    Various aspects of reproduction were studied in three deep-sea octocorals belonging to the order Alcyonacea that co-occur at bathyal depths on the continental edge and the slope of eastern Canada. The main goals were to expand knowledge of deep-water heterotrophic corals and ascertain whether reproductive strategies could explain the known patterns of occurrence. Anthomastus grandiflorus is a gonochoric species with a female-biased sex ratio that exhibits internal fertilization and brooding of planula larvae. Conversely, Primnoa resedaeformis and Keratoisis ornata rely on broadcast spawning and external fertilization; their sexuality remains undetermined as spermatocysts were not found. In P. resedaeformis, the presence of mixed size classes of oocytes in samples from all months, depths, and locations studied suggests continuous oogenesis or overlapping development of oocyte cohorts, indicative of a gametogenic cycle spanning more than a year. No evidence of periodicity was found in this species, although it could have been masked by the striking bathymetric variation in potential relative fecundity (oocytes polyp-1). The two other octocorals displayed a clear annual breeding pattern. Spawning in K. ornata and larval release in A. grandiflorus occurred in late summer and fall, respectively, possibly in response to environmental factors, as supported by shifts in the reproductive peak of A. grandiflorus across latitudes. The three species are presumed to share a nonfeeding larval mode, and data on their reproductive potential do not present any striking disparities. Published data on bycatches and video surveys in Atlantic Canada indicate that the gonochoric brooder A. grandiflorus is more widely distributed than the two free spawners, P. resedaeformis and K. ornata, which is contrary to common dispersal potential paradigms.

  14. Aspects on gametogenesis, fertilization and embryogenesis of two deep-sea polychaetes from Eastern Atlantic cold seeps

    Science.gov (United States)

    Gaudron, S. M.; Hourdez, S.; Olu, K.

    2017-11-01

    We investigated two gonochoristic species of annelid polychaetes (one siboglinid and one polynoid) from cold seeps that ranged from 525 m to 3300 m in depth (Guiness, Worm Hole and Regab pockmarks) on the Gabon and Congo continental margins (Gulf of Guinea). Different aspects of gametogenesis (oocyte diameter, presence of ovisac, spermatozoa shape, and fecundity), fertilization (in vitro fertilization experiments: IVF) and embryogenesis (cleavage rate) were studied. The sampled siboglinid was a new species of Lamellibrachia and the second population of this genus in the Eastern Atlantic. Mean oocyte diameter was about 100 μm and fully-grown primary oocytes were stored in an ovisac, as in other studied siboglinids. The presence of a single spermatozoon was noted within an oviduct, indicating a possible internal fertilization. The rate of cell division at 6 °C was one cleavage every 20 h. Embryos developed normally to the blastula stage after 5-d post-fertilization at atmospheric pressure suggesting some pressure tolerance. The second polychaete was the scale-worm Branchipolynoe cf. seepensis that lives in commensalism in the mantle cavity of Bathymodiolus aff. boomerang. Anatomical reproductive features were similar to those described in B. seepensis from hydrothermal vents on Mid-Atlantic Ridge, with lecithotrophic larval development and continuous gametogenesis. We performed the first IVF carried out on gametes for any deep-sea polynoid species. Fertilization and development occurred but a number of abnormalities were observed demonstrating a limitation to embryogenesis at atmospheric pressure. The rate of cell division was three times faster at 8 °C than at 4 °C with a maximum stage of 8-cells reached after 72 h post-fertilization. We surprisingly observed some oocytes from the negative seawater control during IVF experiments cleaved to the 2-cell stage, demonstrating the possible occurrence of internal fertilization prior to IVF experiment or the accidental

  15. Quantifying in-situ gas hydrates at active seep sites in the eastern Black Sea using pressure coring technique

    Directory of Open Access Journals (Sweden)

    K. U. Heeschen

    2011-12-01

    Full Text Available In the eastern Black Sea, we determined methane (CH4 concentrations, gas hydrate volumes, and their vertical distribution from combined gas and chloride (Cl measurements within pressurized sediment cores. The total gas volume collected from the cores corresponded to concentrations of 1.2–1.4 mol CH4 kg−1 porewater at in-situ pressure, which is equivalent to a gas hydrate saturation of 15–18% of pore volume and amongst the highest values detected in shallow seep sediments. At the central seep site, a high-resolution Cl profile resolved the upper boundary of gas hydrate occurrence and a continuous layer of hydrates in a sediment column of 120 cm thickness. Including this information, a more precise gas hydrate saturation of 22–24% pore volume could be calculated. This volume was higher in comparison to a saturation calculated from the Cl profile alone, resulting in only 14.4%. The likely explanation is an active gas hydrate formation from CH4 gas ebullition. The hydrocarbons at Batumi Seep are of shallow biogenic origin (CH4 > 99.6%, at Pechori Mound they originate from deeper thermocatalytic processes as indicated by the lower ratios of C1 to C2–C3 and the presence of C5.

  16. Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties.

    Science.gov (United States)

    van de Velde, Norbert; Devleesschauwer, Brecht; Leopold, Mardik; Begeman, Lineke; IJsseldijk, Lonneke; Hiemstra, Sjoukje; IJzer, Jooske; Brownlow, Andrew; Davison, Nicholas; Haelters, Jan; Jauniaux, Thierry; Siebert, Ursula; Dorny, Pierre; De Craeye, Stéphane

    2016-10-30

    The occurrence of the zoonotic protozoan parasite Toxoplasma gondii in marine mammals remains a poorly understood phenomenon. In this study, samples from 589 marine mammal species and 34 European otters (Lutra lutra), stranded on the coasts of Scotland, Belgium, France, The Netherlands and Germany, were tested for the presence of T. gondii. Brain samples were analysed by polymerase chain reaction (PCR) for detection of parasite DNA. Blood and muscle fluid samples were tested for specific antibodies using a modified agglutination test (MAT), a commercial multi-species enzyme-linked immunosorbent assay (ELISA) and an immunofluorescence assay (IFA). Out of 193 animals tested by PCR, only two harbour porpoise (Phocoena phocoena) cerebrum samples, obtained from animals stranded on the Dutch coast, tested positive. The serological results showed a wide variation depending on the test used. Using a cut-off value of 1/40 dilution in MAT, 141 out of 292 animals (41%) were positive. Using IFA, 30 out of 244 tested samples (12%) were positive at a 1/50 dilution. The commercial ELISA yielded 7% positives with a cut-off of the sample-to-positive (S/P) ratio≥50; and 12% when the cut-off was set at S/P ratio≥20. The high number of positives in MAT may be an overestimation due to the high degree of haemolysis of the samples and/or the presence of lipids. The ELISA results could be an underestimation due to the use of a multispecies conjugate. Our results confirm the presence of T. gondii in marine mammals in The Netherlands and show exposure to the parasite in both the North Sea and the Eastern Atlantic Ocean. We also highlight the limitations of the tests used to diagnose T. gondii in stranded marine mammals. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Reprint of - Deep-sea coral and hardbottom habitats on the west Florida slope, eastern Gulf of Mexico

    Science.gov (United States)

    Ross, Steve W.; Rhode, Mike; Brooke, Sandra

    2017-09-01

    Until recently, benthic habitats dominated by deep-sea corals (DSC) appeared to be less extensive on the slope of the Gulf of Mexico (GOM) than in the northeast Atlantic Ocean or off the southeastern US. There are relatively few bioherms (i.e., coral-built mounds) in the northern GOM, and most DSCs are attached to existing hard substrata (e.g., authigenically formed carbonate). The primary structure-forming, DSC in the GOM is Lophelia pertusa, but structure is also provided by other living and dead scleractinians, antipatharians (black corals), octocorals (gorgonians, soft corals), hydrocorals and sponges, as well as abundant rocky substrata. The best development of DSCs in the GOM was previously documented within Viosca Knoll oil and gas lease blocks 826 and 862/906 (north-central GOM) and on the Campeche Bank (southern GOM in Mexican waters). This paper documents extensive deep reef ecosystems composed of DSC and rocky hard-bottom recently surveyed on the West Florida Slope (WFS, eastern GOM) during six research cruises (2008-2012). Using multibeam sonar, CTD casts, and video from underwater vehicles, we describe the physical and oceanographic characteristics of these deep reefs and provide size or area estimates of deep coral and hardground habitats. The multibeam sonar analyses revealed hundreds of mounds and ridges, some of which were subsequently surveyed using underwater vehicles. Mounds and ridges in region warrants additional studies to better understand the influences of oceanography and geology on the occurrence of DSC and associated organisms. Protection measures are being considered to ensure the long-term integrity of this diverse ecosystem.

  18. Vertical distributions and speciation of dissolved rare earth elements in the anoxic brines of Bannock Basin, eastern Mediterranean Sea

    Science.gov (United States)

    Schijf, Johan; De Baar, Hein J. W.; Millero, Frank J.

    1995-08-01

    Vertical distributions of dissolved rare earth elements (REEs) are presented for the anoxic, highly sulfidic brines of Bannock Basin in the eastern Mediterranean Sea. REE concentrations at the seawater-brine interface are the highest ever recorded in the water column of an anoxic basin and comparable only to REE concentrations at depth in the porewaters of reducing sediments. Below the seawater-brine interface, throughout the upper of two chemically distinct brine layers, REE concentrations decrease with depth as a result of scavenging, while shale-normalized REE patterns are characterized by little or no fractionation between the light REEs (LREEs) and the heavy REEs (HREEs) and by a positive Ce anomaly. Throughout the lower of the two brine layers REE concentrations are constant, while REE patterns are characterized by the same lack of LREE or HREE enrichment, as well as by the absence of any Ce anomaly. A pronounced REE minimum at the interface between the two brine layers is apparently caused by uptake into dolomite that is formed through in situ recrystallization of Ca carbonate, a process that was previously reported to cause similar minima for Mn and Fe. Calculations of REE speciation, incorporated into a model of REE scavenging (developed by Byrne and Kim, 1990), which uses REE complexation by monocarboxylic acids to represent REE adsorption onto particulate matter, are surprisingly successful at reproducing the unusual shape of REE patterns in the brine. This suggests that this shape, although very different from that of REE patterns in the overlying seawater due to the very high ionic strength of the brine, is the result of much the same processes that constitute REE scavenging in the open ocean.

  19. Wind-driven ocean dynamic effects on the contrasting sea-ice trends around West Antarctica

    Science.gov (United States)

    Lee, Sang-Ki; Volkov, Denis; Lopez, Hosmay; Cheon, Woo Geun; Gordon, Arnold; Liu, Yanyun; Wanninkhof, Rik

    2017-04-01

    Since late 1978, Antarctic sea-ice extent in the East Pacific has retreated persistently over the Amundsen and Bellingshausen Seas in warm seasons, but expanded over the Ross and Amundsen Seas in cold seasons, while an almost opposite trend has occurred in the Atlantic over the Weddell Sea. Previous studies have shown that the contrasting sea-ice trends in the East Pacific and Atlantic could be explained by the strengthening Southern Hemisphere (SH) subpolar low over West Antarctica and associated cold- and warm-air advections and sea-ice drift. By using a surface-forced ocean and sea-ice coupled model, we show that regional wind-driven ocean dynamics also played a key role. In the East Pacific, the strengthening SH westerlies in the region enhanced Ekman upwelling of the warm upper Circumpolar Deep Water, which directly contributed to the retreat of sea ice in warm seasons, and increased the northward Ekman transport of cold Antarctic surface water, which supported the expansion of sea ice in cold seasons. In the Atlantic, the northern branch of the Weddell Gyre strengthened due to the poleward shifting SH westerlies in the region. This in turn sharply increased the meridional thermal gradient across it as constrained by the thermal wind balance. Ocean heat budget analysis further suggests that the strengthened northern branch of the Weddell Gyre acted as a barrier against the poleward ocean heat transport, and thus produced anomalous heat divergence within the Weddell Gyre and anomalous heat convergence north of the gyre. The associated cooling within the Weddell Gyre and the warming north of the gyre contributed to the expansion of sea ice in warm seasons and the retreat in cold seasons, respectively.

  20. Changes in C37 alkenones flux on the eastern continental shelf of the Bering Sea: the record of Emiliania huxleyi bloom over the past 100 years

    Science.gov (United States)

    Harada, N.; Sato, M.; Okazaki, Y.; Oguri, K.; Tadai, O.; Saito, S.; Konno, S.; Jordan, R. W.; Katsuki, K.; Shin, K.; Narita, H.

    2008-12-01

    Flourishes of coccolithophores can be detected by ocean color imagery with data from the satellite-borne Sea-viewing Wide Field-of-view sensor SeaWiFs that was launched in 1997. Thus, temporally and spatially large-scale blooms of Emiliania huxleyi (E. huxleyi) have been distinguished annually in the eastern continental shelf of the Bering Sea since 1997. In 1997, a combination of atmospheric mechanisms produced summer weather anomalies such as calm winds, clear skies, and warm air temperature over the Bering Sea and the weather anomalies caused depletion of the subpycnocline nutrient reservoir (Napp and Hunt, 2001). After depletion of nitrate and silicate, a sustained (more than 4-month-long) bloom of E. huxleyi was observed (Stockwell et al., 2001). Because of the speed and magnitude with which parts of the Bering Sea ecosystem responded to changes in atmospheric factors (Napp and Hunt, 2001) and because a bloom of the coccolithophorid, Coccolithus pelagicus has also been detected in the northeastern Atlantic Ocean off Iceland every year since 1997 (Ostermann, 2001), the appearance of an E. huxleyi bloom in the Bering Sea could be related to atmospherically forced decadal oscillations or global factors. We have investigated spatial expansion and temporal development of E. huxleyi bloom on the continental shelf in the Bering Sea by using a biomarker of E. huxleyi, C37 alkenones flux recorded in the sediments during the past 100 years. As a result, the E. huxleyi bloom had been prominent since 1970"fs at latest during the last 100 years. In this presentation, we will discuss the relationship between E. huxleyi bloom and activity of Aleutian low, and also changes in diatom assemblages. References Napp and Hunt, 2001, Fish Oceanogr., 10, 61-68. Ostermann, 2001, WHOI annual report, pp.17-18. Stockwell et al., 2001, Fish Oceanogr., 10, 99-116.

  1. Biological parameters and feeding behaviour of invasive whelk Rapana venosa Valenciennes, 1846 in the south-eastern Black Sea of Turkey

    Directory of Open Access Journals (Sweden)

    Hacer Saglam

    2014-06-01

    Full Text Available Objective: To determine length-weight relationships, growth type and feeding behavior of the benthic predator Rapa whelk at the coast of Camburnu, south-eastern Black Sea. Methods: Rapa whelk was monthly collected by dredge sampling on the south-eastern Black Sea at 20 m depth. The relationships between morphometric parameters of Rapa whelk were described by linear and exponential models. The allometric growth of each variable relative to shell length (SL was calculated from the function Y=aSLb or logY=loga+blogSL. The functional regression b values were tested by t-test at the 0.05 significance level if it was significantly different from isometric growth. The total time spent on feeding either on mussel tissue or live mussels was recorded for each individual under controlled conditions in laboratory. Results: The length-weight relationships showed positive allometric growth and no inter-sex variability. Body size in the male population was significantly higher than in the individuals of the female. All characters in males and females showed a trend towards allometry rather than isometry. While the total time spent feeding increased with increasing prey size the total time that Rapana venosa spent feeding decreased with increasing Rapa whelk size. The total average feeding time needed by Rapa whelks was 160 min. But they took 310 min on live mussels in 27-28 °C in the laboratory conditions. Conclusions: Length and weight relationships, growth type, total time spent feeding of this species were explained in details for this region. It would be useful to sustainable management in the south-eastern Black Sea of Turkey. The results about the feeding behaviour of this species will contribute to the understanding of the role of this species within the ecosystem.

  2. Air-Sea Interaction at Contrasting Sites in the Eastern Tropical Pacific: Mesoscale Variability and Atmospheric Convection at 10 deg N

    Science.gov (United States)

    2007-02-01

    6979, 1991. [35] H. Hashizumne, S.-P. Xie, T.W. Liu, and K. Takeuchi . Local and remote atmospheric response to tropical instability waves: a global...interaction. Bull. Am. Met. Soc., 85:195 208, 2004. [138] S.-P. Xie, M. Ishiwatari, H. Hashizume, and K. Takeuchi . Coupled ocean-atmiosphere waves on...the equatorial front. Geophys. Res. Lett., 25:3863-3866, 1998. [139] S.-P. Xie, H. Xu, W.S. Kessler, and M. Nonaka . Air-sea interaction over the eastern

  3. Temporal variations in the wind and wave climate at a location in the eastern Arabian Sea based on ERA-Interim reanalysis data.

    Digital Repository Service at National Institute of Oceanography (India)

    Shanas, P.R.; SanilKumar, V.

    in the eastern Arabian Sea based on ERA-Interim reanalysis data P. R. Shanas and V. Sanil Kumar Ocean Engineering, CSIR – National Institute of Oceanography (Council of Scientific & Industrial Research), Dona Paula, Goa 403 004, India Correspondence to: V. Sanil... and Räämet, 2011; Vanem and Walker, 2013). Kumar and Sajiv (2010) carried out a study on variations in long-term wind speed estimates considering different decades in the AS and reported that extreme wind speed has an annual decreasing trend of 1.3 cm s−1...

  4. Diadema mexicanum, a key species of sea urchin in coral reefs of the Eastern Tropical Pacific: state of knowledge and future perspectives.

    OpenAIRE

    Alvarado, Juan José; Reyes-Bonilla, Héctor; Benítez-Villalobos, Francisco

    2016-01-01

    Diadematids are among the most ecologically important sea urchin families. This review presents the state of knowledge of an important member of that family, Diadema mexicanum, in the Tropical Eastern Pacific based on studies carried out mainly in Panama, Costa Rica and Mexico. Density of D. mexicanum is low, fluctuating between 0.008 and 9.5 ind m-2, however under particular conditions such as El Niño, densities reach up to 150 ind m-2. On the other hand, just one event of mass mortality at ...

  5. Studies on the pore water sulfate, chloride and sedimentary methane to understand the sulfate reduction process in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.; Borole, D.V.; Rao, B.R.; Paropkari, A.L.; Joao, H.M.; Kocherla, M.; Sarkar, G.P.; Biswas, G.; Kumar, N.

    Authority of India Limited, New Delhi 100 066, India Sediment cores (~ 5 m length) from ten stations co l lected at water depths of 2 665 ? 3210 m in the eastern Ar a bian Sea were studied for pore water sulphate (SO 2 ?4 ), chl o- ride (Cl....45 ?m) and stored at ? 18 ?C for onshore analyses. Dionex Ion Chromatograph, DX - 600, calibrated with Dionex sta n- dard and working sul phate standard, was used for the d e- termination of sulphate and chl o ride in the pore water samples...

  6. Applicability of the Decision Matrix of North Eastern Atlantic, Mediterranean and connected seas Tsunami Warning System to the Italian tsunamis

    Directory of Open Access Journals (Sweden)

    S. Tinti

    2012-03-01

    Full Text Available After the 2004 Indian Ocean tsunami catastrophe, UNESCO through the IOC (Intergovernmental Oceanographic Commission sponsored the establishment of Intergovernmental Coordination Groups (ICG with the aim to devise and implement Tsunami Warning Systems (TWSs in all the oceans exposed to tsunamis, in addition to the one already in operation in the Pacific (PTWS. In this context, since 2005, efforts have begun for the establishment of TWSs in the Indian Ocean (IOTWS, in the Caribbean area (CARIBE EWS and in the North Eastern Atlantic, the Mediterranean and Connected Seas (NEAMTWS.

    In this paper, we focus on a specific tool that was first introduced in the PTWS routine operations, i.e., the Decision Matrix (DM. This is an easy-to-use table establishing a link between the main parameters of an earthquake and the possible ensuing tsunami in order to make quick decision on the type of alert bulletins that a Tsunami Warning Center launches to its recipients. In the process of implementation of a regional TWS for the NEAM area, two distinct DMs were recently proposed by the ICG/NEAMTWS, one for the Atlantic and the other for the entire Mediterranean area.

    This work applies the Mediterranean NEAMTWS DM to the earthquakes recorded in Italy and compares the action predicted by the DM vs. the action that should be appropriate in view of the observed tsunami characteristics with the aim to establish how good the performance of the Italian TWS will be when it uses the DM for future events. To this purpose, we make use of the parametric catalogue of the Italian earthquakes (CPTI04 compiled in 2004 and the most recent compilation of the Italian tsunami, based on the Italian Tsunami Catalogue of 2004 and the subsequent revisions. In order to better compare the TWS actions, we have identified four different kinds of action coding them from 0 to 3 according to the tsunami severity and have further considered three different distance ranges where

  7. Regression of the level of different heavy metals to size of marine organisms harvested from the "Jiyeh" oil spill zone of the eastern Mediterranean Sea.

    Science.gov (United States)

    Barbour, Elie K; Shaib, Houssam A; Yaghi, Ryan H; Sabra, Alia H

    2009-08-01

    This study aimed to establish a baseline data on regression of the levels of Lead (Pb), Nickel (Ni) and Vanadium (V) to specific size dimensions of selected marine organisms harvested from an oil spill zone of the Eastern Mediterranean Sea. Twenty samples of each of Siganus rivulatus, Mullets and oysters were collected from each of six harvest sites. A total of 1, 3, and 3 respective significant regression equations (p marine organisms. The significant correlation associated with the highest R (2) value was obtained between the Pb (y) level and the width (x) of the Siganus rivulatus (y = -86.833x + 417.72). The other six statistically significant correlations were associated with lower values of R (2) ranging between 0.338 and 0.380. This baseline data will be used in the future to evaluate the self-purification process of pollutants in different sizes of indicator-marine organisms in this part of the Mediterranean Sea.

  8. Environmental correlates of temporary emigration for female Weddell seals and consequences for recruitment

    Science.gov (United States)

    Stauffer, Glenn E.; Rotella, Jay J.; Garrott, Robert A.; Kendall, William L.

    2014-01-01

    In colonial-breeding species, prebreeders often emigrate temporarily from natal reproductive colonies then subsequently return for one or more years before producing young. Variation in attendance–nonattendance patterns can have implications for subsequent recruitment. We used open robust-design multistate models and 28 years of encounter data for prebreeding female Weddell seals (Leptonychotes weddellii [Lesson]) to evaluate hypotheses about (1) the relationships of temporary emigration (TE) probabilities to environmental and population size covariates and (2) motivations for attendance and consequences of nonattendance for subsequent probability of recruitment to the breeding population. TE probabilities were density dependent (βˆBPOP = 0.66,  = 0.17; estimated effects [β] and standard errors of population size in the previous year) and increased when the fast-ice edge was distant from the breeding colonies (βˆDIST = 0.75,  = 0.04; estimated effects and standard errors of distance to the sea-ice edge in the current year on TE probability in the current year) and were strongly age and state dependent. These results suggest that trade-offs between potential benefits and costs of colony attendance vary annually and might influence motivation to attend colonies. Recruitment probabilities were greatest for seals that consistently attended colonies in two or more years (e.g.,  = 0.56, SD = 0.17) and lowest for seals that never or inconsistently attended prior to recruitment (e.g.,  = 0.32, SD = 0.15), where denotes the mean recruitment probability (over all years) for 10-year-old seals for the specified prebreeder state. In colonial-breeding seabirds, repeated colony attendance increases subsequent probability of recruitment to the adult breeding population; our results suggest similar implications for a marine mammal and are consistent with the hypothesis that prebreeders were motivated to attend reproductive colonies to gain reproductive skills or

  9. Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing

    DEFF Research Database (Denmark)

    Ulrich, Clara; Hansen, Jakob Hemmer; Boje, Jesper

    2016-01-01

    in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing....... Hydrogeographical drift modelling suggested that some North Sea juveniles could settle along the coast line of the Skagerrak and the Kattegat. Tagging data suggested that both juveniles and adult fish from the North Sea perform feeding migrations into Skagerrak in summer/autumn. Finally, survey data suggested...... that Skagerrak also belongs to the area distribution of North Sea plaice. The outcomes of the individual studies were then combined into an overall synthesis. The existence of some resident components was evidenced, but it was also demonstrated that North Sea plaice migrate for feeding into Skagerrak and might...

  10. North Atlantic control on precipitation pattern in the eastern Mediterranean/Black Sea region during the last glacial

    OpenAIRE

    O. Kwiecien; H. W. Arz; F. Lamy; Birgit Plessen; A. Bahr; G. H. Haug

    2009-01-01

    Based on proxy records from western Black Sea cores, we provide a comprehensive study of climate change during the last glacial maximum and late-glacial period in the Black Sea region. For the first time we present a record of relative changes in precipitation for NW Anatolia based on variations in the terrigenous supply expressed as detrital carbonate concentration. The good correspondence between reconstructed rainfall intensity in NW Anatolia and past western Mediterranean sea surface temp...

  11. Influence of upwelling on distribution of chaetognath (zooplankton) in the oxygen deficient zone of the eastern Arabian Sea.

    Digital Repository Service at National Institute of Oceanography (India)

    Kusum, K.K.; Vineetha, G.; Raveendran, T.V.; Muraleedharan, K.R.; Biju, A.; Achuthankutty, C.T.

    process. Our observation suggests that the temporal physical event (upwelling) plays a decisive role in the heterogeneity of the spatial abundance, community composition and diversity of chaetognaths in this least studied eastern boundary current system....

  12. Influence of short-term hydrographic variations during the north-east monsoon on picophytoplankton community structure in the eastern Arabian Sea

    Science.gov (United States)

    Rajaneesh, K. M.; Mitbavkar, Smita; Anil, A. C.

    2017-08-01

    The eastern Arabian Sea over the continental margin is a dynamic region subjected to short-term variability in hydrography as a result of various physical forcing such as coastal advection and vertical mixing. In order to assess the influence of hydrography on the picophytoplankton community, a temporal high resolution (every 3 h for nine days) study was carried out at a fixed location (15° 18‧ 46″N, 72° 41‧ 53″E) in the eastern Arabian Sea during the early north-east monsoon (November 2011). The picophytoplankton community comprised of Synechococcus, Prochlorococcus, and picoeukaryotes. Based on the temperature and salinity distribution, the study period was divided into phase I representing a stratified water column and phase II representing a vertically mixed water column. Phase I had higher picophytoplankton abundance with the initial dominance of Prochlorococcus which was later taken over by picoeukaryotes. Towards the end of phase I, with the initiation of vertical mixing, picoeukaryotes were the first to respond to the nutrient influx. As the vertical mixing intensified during phase II, the picophytoplankton abundance declined. Picophytoplankton carbon biomass and their contribution to total phytoplankton biomass was relatively higher during phase I with picoeukaryotes as the major contributors. These transient variations in picophytoplankton abundance highlights the importance of high frequency observations at the single cell level for better understanding the population dynamics in such environments.

  13. Evaluation of genetic diversity of cultivated tea clones (Camellia sinensis (L. Kuntze in the eastern black sea coast by inter-simple sequence repeats (ISSRS

    Directory of Open Access Journals (Sweden)

    Beris Fatih S.

    2016-01-01

    Full Text Available Tea is the most globally consumed drink after spring water and an important breeding plant with high economical value in Turkey. In half a century, various kinds of tea cultivars have been bred in Turkey to improve the quality and yield of tea plants. Since tea reproduces sexually, tea fields vary in quality. Thus, determining the genetic diversity and relationship of the plants to support breeding and cultivation is important. In this study we aimed to determine the genetic diversity of tea cultivars breeding in the Eastern Black Sea coast of Turkey and the genetic relationship between them, to verify whether the qualitative morphological designations of the clones are genetically true by the ISSR markers. Herein, the genetic diversity and relationships of 18 Turkish tea cultivars were determined using 15 ISSR markers with sizes ranging from 250 to 3000 base pairs. The similarity indices among these cultivars were between 0.456 and 0.743. Based on cluster analysis using UPGMA, some of tea cultivars originating from the same geographical position were found to be clustered closely. Our data provide valuable information and a useful basis to assist selection and cloning experiments of tea cultivars and also help farmers to find elite parental clones for tea breeding in the Eastern Black Sea coast of Turkey.

  14. Seasonal spatial patterns in seabird and marine mammal distribution in the eastern Chukchi and western Beaufort seas: Identifying biologically important pelagic areas

    Science.gov (United States)

    Kuletz, Kathy J.; Ferguson, Megan C.; Hurley, Brendan; Gall, Adrian E.; Labunski, Elizabeth A.; Morgan, Tawna C.

    2015-08-01

    The Chukchi and Beaufort seas are undergoing rapid climate change and increased human activity. Conservation efforts for upper trophic level predators such as seabirds and marine mammals require information on species' distributions and identification of important marine areas. Here we describe broad-scale distributions of seabirds and marine mammals. We examined spatial patterns of relative abundance of seabirds and marine mammals in the eastern Chukchi and western Beaufort seas during summer (15 June-31 August) and fall (1 September-20 November) from 2007 to 2012. We summarized 49,206 km of shipboard surveys for seabirds and 183,157 km of aerial surveys for marine mammals into a grid of 40-km × 40-km cells. We used Getis-Ord Gi∗ hotspot analysis to test for cells with higher relative abundance than expected when compared to all cells within the study area. We identified cells representing single species and taxonomic group hotspots, cells representing hotspots for multiple species, and cells representing hotspots for both seabirds and marine mammals. The locations of hotspots varied among species but often were located near underwater canyons or over continental shelf features and slopes. Hotspots for seabirds, walrus, and gray whales occurred primarily in the Chukchi Sea. Hotspots for bowhead whales and other pinnipeds (i.e., seals) occurred near Barrow Canyon and along the Beaufort Sea shelf and slope. Hotspots for belugas occurred in both the Chukchi and Beaufort seas. There were three hotspots shared by both seabirds and marine mammals in summer: off Wainwright in the eastern Chukchi Sea, south of Hanna Shoal, and at the mouth of Barrow Canyon. In fall, the only identified shared hotspot occurred at the mouth of Barrow Canyon. Shared hotspots are characterized by strong fronts caused by upwelling and currents, and these areas can have high densities of euphausiids in summer and fall. Due to the high relative abundance of animals and diversity of taxa

  15. Multi-model assessment of linkages between eastern Arctic sea-ice variability and the Euro-Atlantic atmospheric circulation in current climate

    Science.gov (United States)

    García-Serrano, J.; Frankignoul, C.; King, M. P.; Arribas, A.; Gao, Y.; Guemas, V.; Matei, D.; Msadek, R.; Park, W.; Sanchez-Gomez, E.

    2017-10-01

    A set of ensemble integrations from the Coupled Model Intercomparison Project phase 5, with historical forcing plus RCP4.5 scenario, are used to explore if state-of-the-art climate models are able to simulate previously reported linkages between sea-ice concentration (SIC) anomalies over the eastern Arctic, namely in the Greenland-Barents-Kara Seas, and lagged atmospheric circulation that projects on the North Atlantic Oscillation (NAO)/Arctic Oscillation (AO). The study is focused on variability around the long-term trends, so that all anomalies are detrended prior to analysis; the period of study is 1979-2013. The model linkages are detected by applying maximum covariance analysis. As also found in observational data, all the models considered here show a statistically significant link with sea-ice reduction over the eastern Arctic followed by a negative NAO/AO-like pattern. If the simulated relationship is found at a lag of one month, the results suggest that a stratospheric pathway could be at play as the driving mechanism; in observations this is preferentially shown for SIC in November. The interference of a wave-like anomaly over Eurasia, accompanying SIC changes, with the climatological wave pattern appears to be key in setting the mediating role of the stratosphere. On the other hand, if the simulated relationship is found at a lag of two months, the results suggest that tropospheric dynamics are dominant, presumably due to transient eddy feedback; in observations this is preferentially shown for SIC in December. The results shown here and previous evidence from atmosphere-only experiments emphasize that there could be a detectable influence of eastern Arctic SIC variability on mid-latitude atmospheric circulation anomalies. Even if the mechanisms are robust among the models, the timing of the simulated linkages strongly depends on the model and does not generally mimic the observational ones. This implies that the atmospheric sensitivity to sea

  16. Mass mortality events of the coral Balanophyllia europaea (Scleractinia, Dendrophylliidae) in the Mljet National Park (eastern Adriatic Sea) caused by sea temperature anomalies

    Science.gov (United States)

    Kružić, P.; Popijač, A.

    2015-03-01

    Recurrent climate-induced mass mortalities of marine animals have been recorded in the Mediterranean Sea over the past 15 years. These mortality outbreaks have been associated with positive thermal anomalies. In this study, we assessed long-term (from 2003 to 2013) responses of the temperate coral Balanophyllia europaea to increasing seawater temperatures in the Mljet National Park in the Adriatic Sea (Northern Mediterranean Sea) and described the relationship between recurrent mortality events and sea temperature regimes in the southern Adriatic Sea. Our results indicate that polyp bleaching and tissue necrosis caused the observed mortality. The first observations of B. europaea mortality within the study area in the Mljet NP were in early September 2003. The Mediterranean area experienced high temperatures and hydrographic stability over a period of several weeks throughout that summer, which resulted in a mass mortality event. In the Mljet National Park, the highest impact of mass mortality started during the exceptionally hot summer of 2012, representing one of the most severe mass mortality events ever observed in the Adriatic Sea. In 2012, sea temperatures at a 5 m depth during the summer period (from June to September) ranged from 24.44 to 30.16 °C in the Mljet NP. The northern sites in the Mljet NP were highly impacted, with up to 80 % of B. europaea specimens affected by necrosis, while the southern sites displayed the highest impact, with 90-100 % of affected individuals. Without any coral adaptation to warming and under the present climate-warming trend, new mass mortality events may occur in the near future, possibly causing a major coral biodiversity crisis in the Mediterranean Sea.

  17. Eastern Mediterranean Sea Spatial and Temporal Variability of Thermohaline Structure and Circulation Identified from Observational (T, S) Profiles

    Science.gov (United States)

    2015-12-01

    MEDITERRANEAN SEA SPATIAL AND TEMPORAL VARIABILITY OF THERMOHALINE STRUCTURE AND CIRCULATION IDENTIFIED FROM OBSERVATIONAL (T, S) PROFILES by Nuri...MEDITERRANEAN SEA SPATIAL AND TEMPORAL VARIABILITY OF THERMOHALINE STRUCTURE AND CIRCULATION IDENTIFIED FROM OBSERVATIONAL (T, S) PROFILES 5. FUNDING NUMBERS...variability of thermohaline structure and circulation were investigated. Surface depth shows high seasonal temperature variability through the year

  18. Effects of seasonal and interannual variability in along-shelf and cross-shelf transport on groundfish recruitment in the eastern Bering Sea

    Science.gov (United States)

    Vestfals, Cathleen D.; Ciannelli, Lorenzo; Duffy-Anderson, Janet T.; Ladd, Carol

    2014-11-01

    The Bering Sea responds rapidly to atmospheric perturbations and over the past several decades has experienced extreme variability in both its physical and biological characteristics. These changes can impact organisms that inhabit the region, particularly marine fishes, as normal current patterns to which reproductive habits are tuned can be disrupted, which, in turn, may influence recruitment and population dynamics. To understand the influence of ocean circulation on groundfish recruitment in the eastern Bering Sea, we examined transport along and across the Bering Slope derived from 23 years (1982-2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model. We expected that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment in selected species (Pacific cod, walleye pollock, Greenland halibut, Pacific halibut, and arrowtooth flounder), and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. Variability in along-shelf transport at three transects along the path of the BSC, cross-shelf transport across the 100 and 200 m isobaths, and transport through Unimak Pass were examined. Strong seasonal and interannual variations in flow were observed, with transport typically highest during fall and winter months, coinciding with timing of spawning activity in the five species. Significant correlations were found between transport, BSC position, and groundfish recruitment. Pacific cod, in particular, benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut recruitment increased in relation to increased on-shelf transport through southern canyons. The results of this study improve our understanding of variability in circulation and associated effects on groundfish recruitment in the eastern Bering Sea.

  19. Meiofauna of the deep Eastern Mediterranean Sea: distribution and abundance in relation to bacterial biomass, organic matter composition and other environmental factors

    Science.gov (United States)

    Danovaro, Roberto; Della Croce, Norberto; Eleftheriou, Anastasios; Fabiano, Mauro; Papadopoulou, Nadia; Smith, Chris; Tselepides, Anastasios

    Quantitative information on the abundance and biomass of metazoan meiofauna was obtained from samples collected at 15 deep-sea stations in the Eastern Mediterranean Sea (533-2400m). Meiofaunal abundance was compared to bacterial biomass and other environmental factors such as the total sedimentary organic matter content, the concentrations of the main biochemical classes of organic compounds (i.e. proteins, carbohydrates and lipids) and to ATP. To estimate the sedimentation potential of primary organic matter, sediment bound chloroplastic pigment equivalents (CPE) were assayed. Meiofaunal density was very low ranging from 4 ind.10cm -2 (Station A4, 1658m depth) to 290 ind.10cm -2 (Station A12, 636m depth). Nematodes were the numerically dominant taxon (68% of total meiofauna) and were usually confined to the top 6cm of the sediments. Total meiofaunal biomass ranged from 2.78μgC 10cm -2 (Station A4) to 598.34μgC 10cm -2 (Station 15A). There was a significant decrease in the density of metazoan meiofauna with water depth. Bacterial biomass largely dominated the total biomass (as the sum of bacterial and meiofaunal biomass) with an average of 73.2% and accounted for 35.8% of the living biomass (as ATP carbon) whereas meiofaunal biomass accounted only for 6.56%. Bacterial biomass was significantly related to the DNA concentrations of the sediment. A significant correlation between ATP concentration and CPE content was also found. No correlations were found between meiofauna, ATP and CPE, or between meiofauna and bacterial parameters. The significant relationship between meiofaunal density and the ratio of labile organic matter/total organic matter indicates that deep-sea meiofauna inhabiting an extremely oligotrophic environment (such as the Eastern Mediterranean) may be more nutritionally dependent upon the quality than on the quantity of sedimentary organic matter.

  20. Wind-driven ocean dynamics impact on the contrasting sea-ice trends around West Antarctica

    Science.gov (United States)

    Lee, Sang-Ki; Volkov, Denis L.; Lopez, Hosmay; Cheon, Woo Geun; Gordon, Arnold L.; Liu, Yanyun; Wanninkhof, Rik

    2017-05-01

    Since late 1978, Antarctic sea-ice extent in the East Pacific has retreated persistently over the Amundsen and Bellingshausen Seas in warm seasons, but expanded over the Ross and Amundsen Seas in cold seasons, while almost opposite seasonal trends have occurred in the Atlantic over the Weddell Sea. By using a surface-forced ocean and sea-ice coupled model, we show that regional wind-driven ocean dynamics played a key role in driving these trends. In the East Pacific, the strengthening Southern Hemisphere (SH) westerlies in the region enhanced the Ekman upwelling of warm upper Circumpolar Deep Water and increased the northward Ekman transport of cold Antarctic surface water. The associated surface ocean warming south of 68°S and the cooling north of 68°S directly contributed to the retreat of sea-ice in warm seasons and the expansion in cold seasons, respectively. In the Atlantic, the poleward shifting SH westerlies in the region strengthened the northern branch of the Weddell Gyre, which in turn increased the meridional thermal gradient across it as constrained by the thermal wind balance. Ocean heat budget analysis further suggests that the strengthened northern branch of the Weddell Gyre acted as a barrier against the poleward ocean heat transport, and thus produced anomalous heat divergence within the Weddell Gyre and anomalous heat convergence north of the gyre. The associated cooling within the Weddell Gyre and the warming north of the gyre contributed to the expansion of sea-ice in warm seasons and the retreat in cold seasons, respectively.

  1. Circulation in the northwest Laptev Sea in the eastern Arctic Ocean: Crossroads between Siberian River water, Atlantic water and polynya-formed dense water

    Science.gov (United States)

    Janout, Markus A.; Hölemann, Jens; Timokhov, Leonid; Gutjahr, Oliver; Heinemann, Günther

    2017-08-01

    This paper investigates new observations from the poorly understood region between the Kara and Laptev Seas in the Eastern Arctic Ocean. We discuss relevant circulation features including riverine freshwater, Atlantic-derived water, and polynya-formed dense water, emphasize Vilkitsky Strait (VS) as an important Kara Sea gateway, and analyze the role of the adjacent ˜250 km-long submarine Vilkitsky Trough (VT) for the Arctic boundary current. Expeditions in 2013 and 2014 operated closely spaced hydrographic transects and 1 year-long oceanographic mooring near VT's southern slope, and found persistent annually averaged flow of 0.2 m s-1 toward the Nansen Basin. The flow is nearly barotropic from winter through early summer and becomes surface intensified with maximum velocities of 0.35 m s-1 from August to October. Thermal wind shear is maximal above the southern flank at ˜30 m depth, in agreement with basinward flow above VT's southern slope. The subsurface features a steep front separating warm (-0.5°C) Atlantic-derived waters in central VT from cold (salinities of 34-35. These dense waters are vigorously advected toward the Eurasian Basin and characterize VT as a conduit for near-freezing waters that could potentially supply the Arctic Ocean's lower halocline, cool Atlantic water, and ventilate the deeper Arctic Ocean. Our observations from the northwest Laptev Sea highlight a topographically complex region with swift currents, several water masses, narrow fronts, polynyas, and topographically channeled storms.

  2. Unchanging diet in a stable colony: contemporary and past diet composition of black-legged kittiwakes Rissa tridactyla at Helgoland, south-eastern North Sea

    Science.gov (United States)

    Markones, Nele; Guse, Nils; Hüppop, Ommo; Garthe, Stefan

    2009-09-01

    In contrast to the situation at the west coast of the North Sea, the breeding colony of black-legged kittiwakes Rissa tridactyla at Helgoland in the south-eastern North Sea did not exhibit severe declines since 1990 but instead numbers increased and only lately stabilised. Declines at the west coast of the North Sea were attributed to a lower abundance and lower quality of the key prey, sandeels. We hypothesised that kittiwakes at Helgoland do not rely as heavily on sandeels as their conspecifics. We analysed stomach contents of nestlings and adults of 2001, 2002, 2004 and 2006. In concordance with earlier studies of the 1980s and 1990s, young whiting Merlangius merlangus was the most important prey species in 2001, 2002 and 2004. Clupeids and sandeels were consumed in lower proportions. While earlier studies suggested whiting to originate from fisheries discards, evidence now supports that kittiwakes prey upon whiting in areas of hydrographic fronts. No whiting was recovered in samples of 2006 and the proportion of fish prey was low. Main prey items were polychaete worms (Nereidae), which were presumably consumed as swarming Heteronereis stages. An observed strong rise in water temperature in summer 2006 might have influenced food availability of kittiwakes by inducing swarming of Nereidae. Overall, kittiwakes breeding on Helgoland showed a positive population trend for several decades while mainly feeding on whiting.

  3. Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Jesbin, G.

    / V. Sanil Kumar and J. George: Influence of Indian summer monsoon variability 873 et al., 2013; Sanil Kumar and Anjali Nair, 2015; Amrutha et al., 2016). Long-period swells from the Southern Hemi- sphere were also observed in the eastern AS during.... DMI is represented by anomalous SST gradi- ent between the western equatorial Indian Ocean (50–70◦ E and 10◦ S–10◦ N) and the south-eastern equatorial Indian www.ann-geophys.net/34/871/2016/ Ann. Geophys., 34, 871–885, 2016 874 V. Sanil Kumar and J...

  4. Testing sea-level markers observed in ground-penetrating radar data from Feddet, south-eastern Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B

    2012-01-01

    Ground-penetrating radar (GPR) data have been collected across the modern part (test identification of sea-level markers in GPR data from microtidal depositional environments. Nielsen and Clemmensen (2009) showed...

  5. Prevalence of immunoglobulin E-mediated food allergy in 6-9-year-old urban schoolchildren in the eastern Black Sea region of Turkey.

    Science.gov (United States)

    Orhan, F; Karakas, T; Cakir, M; Aksoy, A; Baki, A; Gedik, Y

    2009-07-01

    The prevalence of adverse reactions to food in childhood in Turkey is not known. We aimed to investigate the prevalence and characteristics of IgE-mediated food allergies (FAs) in 6-9-year-old urban schoolchildren. This cross-sectional study recruited 3500 of the randomly selected 6-9-year-old urban schoolchildren from the eastern Black Sea region of Turkey during 2006. Following a self-administered questionnaire completed by the parents and the child, consenting children were invited for skin prick tests (SPTs) and oral food challenges. Children with suspected IgE-mediated FA were skin prick tested with a predefined panel of food allergens (milk, hen's egg, soy, wheat, peanut, fish, and hazelnut), aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, Alternaria, grass pollen mix, weed pollen mix, and tree pollen mix), and food allergens reported in the questionnaire. All children with a positive SPT to any food were invited for a double-blind, placebo-controlled food challenge (DBPCFC). The prevalence of IgE-mediated FA was established using DBPCFCs. The response rate to the questionnaire was 78.2% (2739/3500). The estimated prevalence of parental-reported IgE-mediated FA was 5.7% (156/2739) [95% confidence interval (CI), 4.83-6.57%]. The rate of sensitization to the food allergens was 33.1% (48/145) in the parental-reported group. The confirmed prevalence of IgE-mediated FA by means of DBPCFC in 6-9-year-old urban schoolchildren living in the eastern Black Sea region of Turkey was 0.80% (22/2739) (95% CI, 0.47-1.13%). The most common allergenic foods were beef (31.8%), cow's milk (18.1%), cocoa (18.1%), hen's egg (13.6%), and kiwi (13.6%). The rate of reported IgE-mediated FA was significantly higher than clinically confirmed FA by means of DBPCFC (odds ratio, 7.46; 95% CI, 4.67-12.01; Pfoods was different and somewhat unique to the eastern Black Sea region of Turkey when compared with western countries.

  6. Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

    Science.gov (United States)

    D'Sa, E. J.; Goes, J. I.; Gomes, H.; Mouw, C.

    2014-06-01

    The absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are reported for the inner shelf, slope waters and outer shelf regions of the eastern Bering Sea during the summer of 2008, when a warm, thermally stratified surface mixed layer lay over a cold pool (Unimak Pass region of the Aleutian Islands, low DOC and ag355 (mean 66.99 ± 7.94 μM; 0.182 ± 0.05 m-1) and a high S (mean 25.95 ± 1.58 μm-1) suggested substantial photobleaching of the Alaska Coastal Water, but high intensities of humic-like and protein-like fluorescence suggested sources of fluorescent DOM from coastal runoff and glacier meltwaters during the summer. The spectral slope S vs. ag355 relationship revealed terrestrial and oceanic end members along with intermediate water masses that were modeled using nonlinear regression equations that could allow water mass differentiation based on CDOM optical properties. Spectral slope S was negatively correlated (r2 = 0.79) with apparent oxygen utilization (AOU) for waters extending from the middle shelf into the deep Bering Sea indicating increasing microbial alteration of CDOM with depth. Although our data show that the CDOM photochemical environment of the Bering Sea is complex, our current information on its optical properties will aid in better understanding of the biogeochemical role of CDOM in carbon budgets in relation to the annual sea ice and phytoplankton dynamics, and to improved algorithms of ocean color remote sensing for this region.

  7. Variability and connectivity of plaice populations from the Eastern North Sea to the Western Baltic Sea, and implications for assessment and management

    DEFF Research Database (Denmark)

    Ulrich, Clara; Boje, Jesper; Cardinale, Massimiliano

    2013-01-01

    in this area is performed, including published and unpublished literature together with the analyses of commercial and survey data and historical tagging data. The results suggest that plaice in Skagerrak is closely associated with plaice in the North Sea, although local populations are present in the area...

  8. Comparative Reproduction Aspects of the Deep-water Shrimps Aristaeomorpha foliacea and Aristeus antennatus (Decapoda, Aristeidae in the Greek Ionian Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    K. Kapiris

    2009-01-01

    Full Text Available In the eastern Ionian Sea, the deep-water shrimps Aristaeomorpha foliacea and Aristeus antennatus constitute a virgin fishing resource, since their maximum abundance depth exceeds commercial exploitation depths. The two sympatric species share a number of common reproductive features, such as summer reproduction. A slight temporal shift in mating activity, ovarian maturation, and spawning period was observed between species. The most notable difference was the more pronounced seasonality in reproductive activity of Aristeus antennatus compared to that of A. foliacea as evidenced by the frequency of inseminated females and functionally mature males, as well as by the shorter ovarian maturation period. Nevertheless, regarding the whole life span, both sexes of Aristeus antennatus exhibit a more extended reproductive activity in comparison to A. foliacea. No notable differentiation of both species existed in comparison to other Mediterranean regions.

  9. Relationships between lake-level changes and water and salt budgets in the Dead Sea during extreme aridities in the Eastern Mediterranean

    Science.gov (United States)

    Kiro, Yael; Goldstein, Steven L.; Garcia-Veigas, Javier; Levy, Elan; Kushnir, Yochanan; Stein, Mordechai; Lazar, Boaz

    2017-04-01

    Thick halite intervals recovered by the Dead Sea Deep Drilling Project cores show evidence for severely arid climatic conditions in the eastern Mediterranean during the last three interglacials. In particular, the core interval corresponding to the peak of the last interglacial (Marine Isotope Stage 5e or MIS 5e) contains ∼30 m of salt over 85 m of core length, making this the driest known period in that region during the late Quaternary. This study reconstructs Dead Sea lake levels during the salt deposition intervals, based on water and salt budgets derived from the Dead Sea brine composition and the amount of salt in the core. Modern water and salt budgets indicate that halite precipitates only during declining lake levels, while the amount of dissolved Na+ and Cl- accumulates during wetter intervals. Based on the compositions of Dead Sea brines from pore waters and halite fluid inclusions, we estimate that ∼12-16 cm of halite precipitated per meter of lake-level drop. During periods of halite precipitation, the Mg2+ concentration increases and the Na+/Cl- ratio decreases in the lake. Our calculations indicate major lake-level drops of ∼170 m from lake levels of 320 and 310 m below sea level (mbsl) down to lake levels of ∼490 and ∼480 mbsl, during MIS 5e and the Holocene, respectively. These lake levels are much lower than typical interglacial lake levels of around 400 mbsl. These lake-level drops occurred as a result of major decreases in average fresh water runoff, to ∼40% of the modern value (pre-1964, before major fresh water diversions), reflecting severe droughts during which annual precipitation in Jerusalem was lower than 350 mm/y, compared to ∼600 mm/y today. Nevertheless, even during salt intervals, the changes in halite facies and the occurrence of alternating periods of halite and detritus in the Dead Sea core stratigraphy reflect fluctuations between drier and wetter conditions around our estimated average. The halite intervals include

  10. The community of deep-sea decapod crustaceans between 175 and 2600 m in submarine canyons of a volcanic oceanic island (central-eastern Atlantic)

    Science.gov (United States)

    Pajuelo, José G.; Triay-Portella, Raül; Santana, José I.; González, José A.

    2015-11-01

    The community structure and faunal composition of deep-sea decapod crustaceans in submarine canyons on the slope off Gran Canaria Island (Canary Islands, central-eastern Atlantic) were investigated. Samples were collected during five research cruises (115 stations) at depths between 175 and 2554 m. A total of 26387 decapod specimens, belonging to 24 families and 38 species, were collected with traps. A cluster analysis of the stations showed four distinct assemblages: (i) in the transition area between shelf and slope (175-302 m); (ii) on the upper slope (361-789 m); (iii) on the middle slope (803-1973 m); and iv) on the lower slope (2011-2554 m). The deep-sea decapod fauna of the Canary Islands is dominated by shrimp of the family Pandalidae, which make up more than 23% of the species. Within the Pandalidae, species of the genus Plesionika stand out as those of greatest abundance on the island slope. The greatest diversity of species was located on the upper slope. The standardized mean abundance and mean biomass for the transition zone between the shelf and slope and for the upper slope were nearly 5 times greater in abundance and 4 times greater in biomass than those estimated for the middle slope, and nearly 53 and 29 times greater for the lower slope, indicating a lower abundance and biomass at the shallower part of the insular slope. The mean weight per individual showed an increasing pattern with depth and an inverse pattern with the bottom temperature and salinity. The existence of depth boundaries around the Canary Islands is known to be closely linked to oceanographic conditions, determined by the water masses present in this archipelago explaining the discontinuities observed at depths of 800 and 2000 m. The boundary observed inside the bathymetric region of the Eastern North Atlantic Central Water can be related with the transition zone between the shelf and the slope of the island.

  11. Physical and thermal properties of mud-dominant sediment from the Joetsu Basin in the eastern margin of the Japan Sea

    Science.gov (United States)

    Goto, Shusaku; Yamano, Makoto; Morita, Sumito; Kanamatsu, Toshiya; Hachikubo, Akihiro; Kataoka, Satsuki; Tanahashi, Manabu; Matsumoto, Ryo

    2017-12-01

    Physical properties (bulk density and porosity) and thermal properties (thermal conductivity, heat capacity, specific heat, and thermal diffusivity) of sediment are crucial parameters for basin modeling. We measured these physical and thermal properties for mud-dominant sediment recovered from the Joetsu Basin, in the eastern margin of the Japan Sea. To determine thermal conductivity, heat capacity, and thermal diffusivity, the dual-needle probe method was applied. Grain density and grain thermal properties for the mud-dominant sediment were estimated from the measured physical and thermal properties by applying existing models of physical and thermal properties of sediment. We suggest that the grain density, grain thermal conductivity, and grain thermal diffusivity depend on the sediment mineral composition. Conversely, the grain heat capacity and grain specific heat showed hardly any dependency on the mineral composition. We propose empirical formulae for the relationships between: thermal diffusivity and thermal conductivity, and heat capacity and thermal conductivity for the sediment in the Joetsu Basin. These relationships are different from those for mud-dominant sediment in the eastern flank of the Juan de Fuca Ridge presented in previous work, suggesting a difference in mineral composition, probably mainly in the amount of quartz, between the sediments in that area and the Joetsu Basin. Similar studies in several areas of sediments with various mineral compositions would enhance knowledge of the influence of mineral composition.

  12. European Integration and the Transition of Eastern European States. The New Central Europe and Romania's Interest in Regional Cooperation in the Black Sea - Danube Region

    Directory of Open Access Journals (Sweden)

    Flore POP

    2003-01-01

    Full Text Available This short article presents the most important directions of the evolution of Central and Eastern Europe during the second half of the 20th century during the period marked by the coming into power and then the downfall of the communism. One could also note that the Central and Eastern European countries have undergone several political and economic transitions- and for Romania’s case- the burdening heritage of the austerity economic policy that has been implemented during the years will affect the economic development of the countries on the long term. The transition towards market economy was realized upon the political decision of political accession to the free market principle. The new beginning of the regional integration process made the countries in the Danube-Black Sea region, sign new agreements for political and economic cooperation. The emergence of new countries on European and Asian maps opens new opportunities for regional cooperation, especially for environmental issues, which brings new dimensions for the global process of European integration and of the integration of the regional economies into the global economies.

  13. Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis.

    Science.gov (United States)

    Maniscalco, John M; Springer, Alan M; Adkison, Milo D; Parker, Pamela

    2015-01-01

    Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct population segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the western population) in a matrix population model to estimate the trend and strength of the recovery across this region between 2003 and 2013. The modeled population trend was projected into the future based on observed variation in vital rates and a prospective elasticity analysis was conducted to determine future trends and which vital rates pose the greatest threats to recovery. The modeled population grew at a mean rate of 3.5% per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile survival, and least sensitive to changes in fecundity. A population decline could be expected with only a 6% decrease in adult survival, whereas a 32% decrease in fecundity would be necessary to bring about a population decline. These results have important implications for population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality.

  14. The Scotia Sea and the Drake Passage as an orographic barrier for the Antarctic Circumpolar Current

    Science.gov (United States)

    Tarakanov, R. Yu.

    2012-04-01

    It is shown on the basis of the data of the Russian Academy of Sciences expeditions in 2003-2010, the historical CTD database, the WOCE climatology, and the satellite altimetry that the area of the Scotia Sea and the Drake Passage is even a greater significant orographic barrier for the eastward Antarctic Circumpolar Current (ACC) than was previously thought. It is the current concept that this barrier is the most important for the ACC; it consists of three obstacles: the Hero Ridge with the Phoenix Rift, the Shackleton Ridge, and the North Scotia Ridge with the relatively shallow eastern part of the Scotia Sea. Despite the fact that all three obstacles are permeable for the layer of the Circumpolar Bottom Water (CBW; 28.16 intensified ACC jets. Herewith, the upper CBW boundary is the lower limit of the circumpolar coverage of the ACC jets. This result is confirmed by the near zero estimate of the total CBW transport according to the three series of the LADCP measurements on the sections across the Drake Passage. It is shown that the transformation (cooling and freshening) of the CBW layer, which occurs owing to the flow of the ACC over the Shackleton Ridge, is associated with the shape and location of the ridge in the Drake Passage. The high southern part of this ridge is a partially permeable screen for the eastward CBW transport behind which the colder and fresher waters of the Weddell Sea and the Bransfield Strait of the same density range as the CBW penetrate into the ACC zone. The partial permeability of the Shackleton Ridge for the CBW layer leads to the salinization of this layer on the eastern side of the ridge and to the CBW's freshening on the western side of this ridge, which is observed across the entire Drake Passage.

  15. Sustainability Organic Agriculture and Livestock Production with Respect to European Union in Eastern Anatolia and East Black Sea Regions

    Directory of Open Access Journals (Sweden)

    Vecihi Aksakal

    2016-11-01

    Full Text Available The majority of farm households in Turkey and especially the Eastern Anatolia are still based on low-input semi subsistence agriculture and livestock production. Despite a slow decline in recent years, agriculture and livestock production remains a major employer in Turkey and it is a significant contributor to the country’s gross domestic product, GDP. Whist Turkey is one of the EU candidate countries, is self sufficient in food production and Turkish agriculture is poorly structured inefficient, with farming in the Eastern Anatolia being mainly subsistence farming. Yet, these traditional rural structures combined with poor access to low level of education and low level of off-farm unemployment problem makes the situation more complicated and unsustainable. The best way to promote sustainability, better and higher production of Eastern Anatolian and rural Turkey is to invest in the local people, villages through improved, continuing and effective agricultural and livestock programs in particular. Investment in human capital especially in the rural areas leads to more employment opportunities through entrepreneurship and innovation in organic agriculture and livestock production. A holistic approach to developing and improving supply chains could unlock the potential for sophisticated, state-of-the-art organic agriculture and livestock producers and businesses in the region to become EU and global players. Eastern Anatolian livestock producers and the farmers have the ambitions to take part in future progress because the region is naturally organic not by design but default. It is for sure that present potential of the region has not been fully determined and utilized. EU has greatly benefited from previous enlargements economically, politically and socially. When European Union (EU and Turkish Government relations considered and accession of Turkey to EU would be the logical consequence of the previous accessions. The screening on chapter 11

  16. Histophysiological observations on the external auditory meatus, middle, and inner ear of the Weddell seal (Leptonychotes weddelli).

    Science.gov (United States)

    Welsch, U; Riedelsheimer, B

    1997-10-01

    The external auditory meatus, middle, and inner ear of the deep-diving Weddell seal (Leptonychotes weddelli) were studied with light microscopic, histological, and histochemical techniques in order to contribute to the open discussion on the orientation of this seal in the darkness of the deep Antarctic seas. The external auditory meatus is characterized by a well-developed venous plexus, single apocrine ceruminous, and numerous holocrine sebaceous glands and an incomplete tube of elastic cartilage. The tympanic membrane is comprised of two layers of radially and concentrically arranged collagen fibers and by elastic fibers which are concentrated in the outer part of the ear drum. The tympanic cavity is lined by a pseudostratified prismatic ciliated epithelium with goblet cells; a plexus of wide venous vessels marks the subepithelial lamina propria. The cochlea is about 10 mm high and forms about two and a half turns. The richly pigmented stria vascularis is well vascularized, while the cell-rich prominentia spiralis contains only single small blood vessels. The organ of Corti contains one row of inner and three rows of outer hair cells. Cells of Hensen, Claudius, and Boettcher are present. The basilar membrane is of comparatively uniform simple structure and is composed of abundant glycoproteins, proteoglycans, collagenous fibers, and the loose tissue of the tympanal layer. The spiral ligament is built up by abundant proteoglycans and a complex system of radial and concentric collagen fibers; close to the osseous wall of the bony cochlea it contains fine elastic fibers. The inner zone of the osseous wall of the cochlea strikingly contains hyaline cartilage. The thin lamina spiralis ossea is covered by a limbus spiralis with interdental cells secreting the lamina tectoria, which has a fibrous texture and contains glycoproteins and negatively charged components.

  17. Altimeter-derived flow field over a newly identified coastal ocean boundary in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, M.K.; Somayajulu, Y.K.; Swamy, G.N.

    part, tapers off towards north and bulges towards south. In the present communication, the T/P-derived flow pattern over this new boundary is presented. The derived flow pattern shows the general dominance of meso-scale eddies in the Arabian Sea...

  18. Quantification of the early small-scale fishery in the north-eastern Baltic Sea in the late 17th century.

    Directory of Open Access Journals (Sweden)

    Aare Verliin

    Full Text Available Historical perspectives on fisheries and related human behaviour provide valuable information on fishery resources and their exploitation, helping to more appropriately set management targets and determine relevant reference levels. In this study we analyse historical fisheries and fish trade at the north-eastern Baltic Sea coast in the late 17th century. Local consumption and export together amounted to the annual removal of about 200 tonnes of fish from the nearby sea and freshwater bodies. The fishery was very diverse and exploited altogether one cyclostome and 17 fish species with over 90% of the catch being consumed locally. The exported fish consisted almost entirely of high-valued species with Stockholm (Sweden being the most important export destination. Due to rich political history and natural features of the region, we suggest that the documented evidence of this small-scale fishery should be considered as the first quantitative summary of exploitation of aquatic living resources in the region and can provide a background for future analyses.

  19. Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: concentration, isotopic composition and maternal transfer.

    Science.gov (United States)

    Páez-Osuna, F; Calderón-Campuzano, M F; Soto-Jiménez, M F; Ruelas-Inzunza, J R

    2010-03-01

    Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the "arribada" event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95+/-0.18microgg(-1)) and egg samples (yolk, 0.80+/-0.10microg g(-1); albumen, 1.08+/-0.20microg g(-1); eggshell, 1.05+/-0.20microg g(-1)) were comparable or even lower than those found in other sea turtles. The isotope ratios ((206)Pb/(207)Pb and (206)Pb/(208)Pb) in blood (1.183+/-0.0006 and 2.452+/-0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188+/-0.005 and 2.455+/-0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Miocene-Pliocene alkenone and coccolithophorid stable isotopic data for sea surface condition reconstructions in the Eastern Equatorial Pacific (IODP Site U1338). (Invited)

    Science.gov (United States)

    Beltran, C.; Rousselle, G.; Raffi, I.; Backman, J.; Sicre, M.; de Rafélis, M.; Iodp Expedition 320/321 Shipboard Scientific Party

    2010-12-01

    Coccolithophores play an important role in earth’s biogeochemical cycles due to their great abundance, fast turnover rates, and their ability to carry out photosynthesis and calcification. Although calcareous nannofossils are major producers of carbonates and alkenones in the ocean, the use of coccoliths as a recorder of seawater δ18O and δ13C has been limited by the difficulty of isolating them from the bulk carbonates. Here, we present temperature and δ18O reconstructions over the mid-Miocene through the Plio-Pleistocene from IODP Site U1338 of Expedition 320/321 in the Eastern Equatorial Pacific. Isotopic data were obtained from mono-specific Noealherabdaceae dominated coccolith fine fractions isolated using the granulometric separation technique developed by Minoletti et al., (2009). The nannofossil assemblage compositions and the alkenone-derived SSTs were determined in the same samples and combined to the δ18O and δ13C values measured on the alkenone producing coccoliths to evaluate past sea-surface environmental conditions prevailing in the Equatorial Pacific. These new data based on organic and inorganic compounds produced by coccolithophores offer the potential to extract environmental informations including: sea surface temperature (alkenone unsaturation ratio) and salinity and fertility conditions (coccolith isotopic ratio). Using multiple geochemical proxies derived from a single group of plankton have huge potential for paleoenvironmental reconstructions.

  1. Nursery areas of red mullet ( Mullus barbatus), hake ( Merluccius merluccius) and deep-water rose shrimp ( Parapenaeus longirostris) in the Eastern-Central Mediterranean Sea

    Science.gov (United States)

    Carlucci, Roberto; Giuseppe, Lembo; Porzia, Maiorano; Francesca, Capezzuto; Alessandra, Marano Chiara; Letizia, Sion; Teresa, Spedicato Maria; Nicola, Ungaro; Angelo, Tursi; D'Onghia, Gianfranco

    2009-08-01

    The spatial pattern of the nursery areas of red mullet ( Mullus barbatus), hake ( Merluccius merluccius) (Linnaeus, 1758) and deep-water rose shrimp ( Parapenaeus longirostris) (Lucas, 1846) was studied in the South Adriatic and North Ionian Seas (Eastern-Central Mediterranean) applying geostatistical techniques and data from time series trawl surveys conducted in the area. The analysed variables were: R (number of recruits/km 2) and R/Tot (fraction of recruits on the total sampled population). The structural analysis showed a spatial pattern of both variables characterized by continuity on a small scale. Predictions of nursery area localization with probability of finding recruits at different threshold values were obtained through median indicator kriging. For the red mullet the nurseries were mainly identified in the South Adriatic Sea off the Gargano peninsula and between Molfetta and Monopoli within 50 m in depth. The main concentration of hake juveniles was found to be between 100 and 200 m in depth along the Gargano peninsula and between Otranto and Santa Maria di Leuca, where a nursery of deep-water rose shrimp was also detected. An overlapping depth, between 100 and 200 m, was identified for hake and deep-water rose shrimp nurseries. Protection of these areas through limitations of fishing pressure is discussed.

  2. Toxic element concentrations in the bottlenose (Tursiops truncatus), striped (Stenella coeruleoalba) and Risso's (Grampus griseus) dolphins stranded in eastern Adriatic Sea.

    Science.gov (United States)

    Bilandžić, Nina; Sedak, Marija; Ðokić, Maja; Ðuras Gomerčić, Martina; Gomerčić, Tomislav; Zadravec, Manuela; Benić, Miroslav; Prevendar Crnić, Andrea

    2012-09-01

    Concentrations of cadmium (Cd), arsenic (As), mercury (Hg) and lead (Pb) were measured in muscle, liver and kidney of three cetacean species, the bottlenose (Tursiops truncatus), striped (Stenella coeruleoalba) and Risso's (Grampus griseus) dolphins from the Croatian waters of the Adriatic Sea. In all three dolphin species Cd levels decreased in tissues in the order: kidney > liver > muscle, while As and Pb decreased in the order: liver > kidney > muscle for striped and Risso's dolphins, but with the order reversed for liver and kidney in the bottlenose dolphin for Pb. Levels of Hg consistently followed the order: liver > muscle > kidney, with mean concentrations in the liver being 11-34 times higher than in the other tissues. The highest mean concentrations of trace elements were measured in Risso's dolphins at 14.9 μg/g wet weight, for Cd in the kidney, and concentrations in the liver of 2.41, 1,115 and 0.63 μg/g for As, Hg and Pb, respectively. Statistically significant differences between the three dolphin species were determined for Cd, Hg and Pb in liver tissues, for As in muscle and for Cd in kidney. Significant correlations of metals between tissues were determined in all three species. The results presented give an indication of the environmental condition with regard to the content of toxic metals along the eastern coast of the Adriatic Sea.

  3. Age, growth and utility of otolith morphometrics as a predictor of age in the wrasse Coris julis (Labridae from the eastern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Frane Škeljo

    2012-09-01

    Full Text Available Age and growth of Coris julis were determined by examining sagittal otoliths belonging to fish sampled between November 2008 and October 2009 in the eastern Adriatic Sea (north-central Mediterranean Sea. A total of 1102 specimens (528 males, 487 females and 87 individuals of indeterminate sex, ranging from 48 to 222 mm total length were analysed. Ninety-two per cent of the otoliths were readable and 68% of the specimens had two readings in agreement. Counting of daily rings revealed that the second opaque ring represents the first annulus (315.1±27.8 daily rings. The maximum observed age was 7 years for males and 5 years for females, with males dominating in higher age classes ( > 3 years and females in age classes 1+ and 2+. Growth was described by the von Bertalanffy growth curves and significant differences were found between males (L∞=29.10 cm, k=0.12 and t0=–1.48 and females (L∞=21.27 cm, k=0.21 and t0=–1.08. Otolith mass, length, width and thickness were determined for the otoliths belonging to 465 fish and the utility of these morphometrics as a predictor of age was evaluated. The most precise age estimations were obtained from the otolith length data, followed by the otolith mass.

  4. A Perspective on Sea Level Rise and Coastal Storm Surge from Southern and Eastern Africa: A Case Study Near Durban, South Africa

    Directory of Open Access Journals (Sweden)

    Derek D. Stretch

    2012-03-01

    Full Text Available Recent coastal storms in southern Africa have highlighted the need for more proactive management of the coastline. Within the southern and eastern African region the availability of coastal information is poor. The greatest gap in information is the likely effects of a combination of severe sea storms and future sea level rise (SLR on the shoreline. This lack of information creates a barrier to informed decision making. This research outlines a practical localized approach to this problem, which can be applied as a first order assessment within the region. In so doing it provides a cost effective and simple decision support tool for the built environment and disaster professionals in development and disaster assessments. In a South African context the newly promulgated Integrated Coastal Management Act requires that all proposed coastal developments take into consideration future SLR, however such information currently does not exist, despite it being vital for informed planning in the coastal zone. This practical approach has been applied to the coastline of Durban, South Africa as a case study. The outputs are presented in a Geographic Information System (GIS based freeware viewer tool enabling ease of access to both professionals and laypersons. This demonstrates that a simple approach can provide valuable information about the current and future risk of flooding and coastal erosion under climate change to buildings, infrastructure as well as natural features along the coast.

  5. The prospects of nuclear power development in the eastern part of the Baltic Sea region as a factor of the formation of international relations system in the region

    Directory of Open Access Journals (Sweden)

    Mezhevich Nikolai

    2013-05-01

    Full Text Available The current development of economic diplomacy in the world is determined by a combination of globalization and regionalization. In addition, it has an economic dimension. At the same time, the Baltic Sea region demonstrates large-scale politicisation of economic cooperation. The development of nuclear power in the eastern part of the Baltic Sea is indicative of the effectiveness of political and economic cooperation in the region. The author believes that Russia and the three Baltic States of Estonia, Latvia and Lithuania have the economic and technological opportunities for building up cooperation in the field of energy. This points to a question whether the traditional patterns of relations that developed among these countries in the past can be changed. A more pronounced international division of labour accompanied by the historically developed specialization of Russia makes nuclear power an important factor in Russia’s economic diplomacy. The promotion of Russian energy projects in the region contributes to the development of a system of mutually beneficial ties. The increasing energy deficiency in the region can serve an economic prerequisite to this process.

  6. Predicting the impacts of Mississippi River diversions and sea-level rise on spatial patterns of eastern oyster growth rate and production

    Science.gov (United States)

    Wang, Hongqing; Chen, Qin; La Peyre, Megan K.; Hu, Kelin; La Peyre, Jerome F.

    2017-01-01

    There remains much debate regarding the perceived tradeoffs of using freshwater and sediment diversions for coastal restoration in terms of balancing the need for wetland restoration versus preserving eastern oyster (Crassostrea virginica) production. Further complicating the issue, climate change-induced sea-level rise (SLR) and land subsidence are also expected to affect estuarine water quality. In this study, we developed a process-based numerical modeling system that couples hydrodynamic, water quality, and oyster population dynamics. We selected Breton Sound Estuary (BSE) (∼2740 km2) in the eastern Mississippi River Deltaic Plain since it is home to several of the largest public oyster seed grounds and private leases for the Gulf coast. The coupled oyster population model was calibrated and validated against field observed oyster growth data. We predicted the responses of oyster population in BSE to small- (142 m3 s−1) and large-scale (7080 m3 s−1) river diversions at the Caernarvon Freshwater Diversion structure planned in the 2012 Coastal Master Plan (Louisiana) under low (0.38 m) and high (1.44 m) relative sea-level rise (RSLR = eustatic SLR + subsidence) compared to a baseline condition (Year 2009). Model results showed that the large-scale diversion had a stronger negative impact on oyster population dynamics via freshening of the entire estuary, resulting in reduced oyster growth rate and production than RSLR. Under the large-scale diversion, areas with optimal oyster growth rates (>15 mg ash-free dry weight (AFDW) oyster−1 wk−1) and production (>500 g AFDW m−2 yr−1) would shift seaward to the southeastern edge of the estuary, turning the estuary into a very low oyster production system. RSLR however played a greater role than the small-scale diversion on the magnitude and spatial pattern of oyster growth rate and production. RSLR would result in an overall estuary-wide decrease in oyster growth rate and production as a

  7. Absorption and fluorescence properties of the eastern Bering Sea in the summer with special reference to the influence of a Cold Pool

    Science.gov (United States)

    D'Sa, E. J.; Goes, J. I.; Gomes, H.; Mouw, C.

    2013-12-01

    The absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are reported for the inner shelf, slope waters and outer shelf regions of the eastern Bering Sea during the summer of 2008, when a warm, thermally stratified surface mixed layer lay over a Cold Pool ( 250 m) revealed low values of ag355 (0.155 ± 0.03 m-1) and S (15.45 ± 1.78 μm-1) indicative of microbial degradation of CDOM in deep waters. DOC concentrations, however were not significantly different suggesting CDOM sources and sinks to be uncoupled from DOC. Along the productive "green belt" in the outer shelf/slope region, absorption and fluorescence properties indicated the presence of fresh and degraded autochthonous DOM. Near the Unimak Pass region of the Aleutian Islands, low DOC and ag355 (mean 66.99 ± 7.94 μM; 0.182 ± 0.05 m-1) and a high S (mean 25.95 ± 1.58 μm-1) suggested substantial photobleaching of the Alaska Coastal Waters, but high intensities of humic-like and protein-like fluorescence suggested sources of fluorescent DOM from coastal runoff and glacier melt waters during the summer. Although our data show that the CDOM photochemical environment of the Bering Sea is complex, our current information on its optical properties will aid in better understanding of the biogeochemical role of CDOM in carbon budgets in relation to the annual sea ice and phytoplankton dynamics, and to improved algorithms of ocean color remote sensing for this region.

  8. Evolutionary melting pots: a biodiversity hotspot shaped by ring diversifications around the Black Sea in the Eastern tree frog (Hyla orientalis).

    Science.gov (United States)

    Dufresnes, Christophe; Litvinchuk, Spartak N; Leuenberger, Julien; Ghali, Karim; Zinenko, Oleksandr; Stöck, Matthias; Perrin, Nicolas

    2016-09-01

    Hotspots of intraspecific genetic diversity, which are of primary importance for the conservation of species, have been associated with glacial refugia, that is areas where species survived the Quaternary climatic oscillations. However, the proximate mechanisms generating these hotspots remain an open issue. Hotspots may reflect the long-term persistence of large refugial populations; alternatively, they may result from allopatric differentiation between small and isolated populations, that later admixed. Here, we test these two scenarios in a widely distributed species of tree frog, Hyla orientalis, which inhabits Asia Minor and southeastern Europe. We apply a fine-scale phylogeographic survey, combining fast-evolving mitochondrial and nuclear markers, with a dense sampling throughout the range, as well as ecological niche modelling, to understand what shaped the genetic variation of this species. We documented an important diversity centre around the Black Sea, composed of multiple allopatric and/or parapatric diversifications, likely driven by a combination of Pleistocene climatic fluctuations and complex regional topography. Remarkably, this diversification forms a ring around the Black Sea, from the Caucasus through Anatolia and eastern Europe, with terminal forms coming into contact and partially admixing in Crimea. Our results support the view that glacial refugia generate rather than host genetic diversity and can also function as evolutionary melting pots of biodiversity. Moreover, we report a new case of ring diversification, triggered by a large, yet cohesive dispersal barrier, a very rare situation in nature. Finally, we emphasize the Black Sea region as an important centre of intraspecific diversity in the Palearctic with implications for conservation. © 2016 John Wiley & Sons Ltd.

  9. An example of aerosol pattern variability over bright surface using high resolution MODIS MAIAC: The eastern and western areas of the Dead Sea and environs

    Science.gov (United States)

    Sever, Lee; Alpert, Pinhas; Lyapustin, Alexei; Wang, Yujie; Chudnovsky, Alexandra

    2017-09-01

    The extreme rate of evaporation of the Dead Sea (DS) has serious implications for the surrounding area, including atmospheric conditions. This study analyzes the aerosol properties over the western and eastern parts of the DS during the year 2013, using MAIAC (Multi-Angle Implementation of Atmospheric Correction) for MODIS, which retrieves aerosol optical depth (AOD) data at a resolution of 1 km. The main goal of the study is to evaluate MAIAC over the study area and determine, for the first time, the prevailing aerosol spatial patterns. First, the MAIAC-derived AOD data was compared with data from three nearby AERONET sites (Nes Ziona - an urban site, and Sede Boker and Masada - two arid sites), and with the conventional Dark Target (DT) and Deep Blue (DB) retrievals for the same days and locations, on a monthly basis throughout 2013. For the urban site, the correlation coefficient (r) for DT/DB products showed better performance than MAIAC (r = 0.80, 0.75, and 0.64 respectively) year-round. However, in the arid zones, MAIAC showed better correspondence to AERONET sites than the conventional retrievals (r = 0.58-0.60 and 0.48-0.50 respectively). We investigated the difference in AOD levels, and its variability, between the Dead Sea coasts on a seasonal basis and calculated monthly/seasonal AOD averages for presenting AOD patterns over arid zones. Thus, we demonstrated that aerosol concentrations show a strong preference for the western coast, particularly during the summer season. This preference, is most likely a result of local anthropogenic emissions combined with the typical seasonal synoptic conditions, the Mediterranean Sea breeze, and the region complex topography. Our results also indicate that a large industrial zone showed higher AOD levels compared to an adjacent reference-site, i.e., 13% during the winter season.

  10. Monsoon related changes in sea surface productivity and water column denitrification in the Eastern Arabian Sea during the last glacial cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Oba, T.; Chodankar, A.R.; Kuramoto, T.; Yamamoto, M.; Minagawa, M.

    -series of sedimentary organic-carbon (C org ), P alkenone and y 13 C org for the last 100 kyr, together, The Arabian Sea (AS) sedimentary records have shown contrasting monsoon driven productivity on a western-AS (Emeis et al., 1995; Spaulding and Oba, 1992...: Reichart et al., -monsoons and -thin arrow is the direction of winter-monsoons. symbolize summer monsoon currents (continuous) and winter The Holocene-LGM y 18 O G.sacculifer contrast is ~2x similar to previously reported contrasts for near- by sediment...

  11. Spatial distribution of phytoplankton in Spring 2004 along a transect in the eastern part of the North Sea

    DEFF Research Database (Denmark)

    Skaloud, P.; Rezacova, M.; Ellegaard, Marianne

    2006-01-01

    of algae. The other less abundant groups were Dinophyceae, Dictyochophyceae, Prasinophyceae and Chlorophyceae. The pattern of distribution of diatoms and dinophytes along the transect was more or less similar, with larger numbers of cells found close to both the eastern and western parts of the transect....... Altogether 144 species of algae were identified by light, epifluorescence and electron microscopy. Some ecological preferences were found on the basis of measured environmental parameters and compared with the literature. Possible controlling mechanisms for the distribution patterns of the plankton algae...

  12. Impacts on phytoplankton dynamics by free-drifting icebergs in the NW Weddell Sea

    Science.gov (United States)

    Vernet, M.; Sines, K.; Chakos, D.; Cefarelli, A. O.; Ekern, L.

    2011-06-01

    Glacier ice released to the oceans through iceberg formation has a complex effect on the surrounding ocean waters. We hypothesized that phytoplankton communities would differ in abundance, composition and production around or close to an iceberg. This paper tests the influence of individual icebergs on scales of meters to kilometers, observed through shipboard oceanographic sampling on March-April 2009. Surface waters (integrated 0-100 m depth, within the euphotic zone) sampled close to the iceberg C-18a (salps Salpa thompsonii, are expected to exert heavy grazing pressure on phytoplankton, the krill on large cells >10 μm and the salps on smaller cells, 3-10 μm. The iceberg's main influence in the austral fall is measured not so much by phytoplankton accumulation but by reactivation of the classic Antarctic food chain, facilitating diatom growth and sustaining high Antarctic krill populations.

  13. Benthic diatoms (Bacillariophyta) from seepages and streams on James Ross Island (NW Weddell Sea, Antarctica)

    Czech Academy of Sciences Publication Activity Database

    Kopalová, K.; Veselá, J.; Elster, Josef; Nedbalová, Linda; Komárek, Jiří; Van de Vijver, B.

    2012-01-01

    Roč. 145, č. 2 (2012), s. 190-208 ISSN 2032-3913 R&D Projects: GA MŠk ME 934; GA MŠk ME 945; GA ČR GA206/05/0253 Institutional research plan: CEZ:AV0Z60050516 Keywords : James Ross Island * Antarctic Peninsula * Bacillariophyceae Subject RIV: EF - Botanics Impact factor: 1.192, year: 2012

  14. Histological and Morphological Aspects of Reproduction in Male Blackspotted Smooth-Hound Mustelus punctulatus in the Adriatic Sea (Eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Romana Gračan

    2016-01-01

    Full Text Available We present first data on reproductive biology of male blackspotted smooth-hound Mustelus punctulatus in the Adriatic Sea and first histological examination of gonads at different maturation stages and seasonal cycles for this species. We collected samples from 117 male specimens of M. punctulatus ranging in length from 44.6 to 126.5 cm, caught by commercial bottom trawls in the North-Central Adriatic Sea. Microscopic observation revealed a diametric development of testes, in which round-shaped spermatocysts have zonal arrangement, showing seven different stages of development. Males began to mature when they were between 61 and 88 cm body length, which was indicated by the presence of functional claspers or appearance of the spermatogenic cysts. While the smallest mature shark was only 80 cm long, all animals longer than 89 cm were sexually mature. The seasonal analysis of the testes indicated that mature spermatozoa dominated in testes during the first half of the year with a peak in May and June, after which followed less active period during July and August.

  15. Description of the first Lessepsian squid migrant, Sepioteuthis lessoniana (CEPHALOPODA: Loliginidae, in the Aegean Sea (Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    E. LEFKADITOU

    2009-12-01

    Full Text Available Loliginid squids of the Sepioteuthis lessoniana complex are widely spread in the Indo-Pacific Ocean, where they constitute a commercially important resource for neritic fisheries. Sepioteuthis lessoniana is the only Lessepsian squid migrant till now, recorded for the first time in the Mediterranean in 2002 along the Turkish Levantine coasts. Two maturing males, with mantle lengths 193 mm and 244 mm, have been recently caught near the coasts of Rhodes Island (SE Aegean, extending the species distribution northward, into Hellenic waters. Their identity was confirmed by comparison of the main body, beak characteristics and morphometric measurements with those available in the literature for this species. Suspected expansion of the Lessepsian loliginid into the Aegean Sea, due to the gradual warming of the sea, is discussed.

  16. The sedimentary regime around northern Sylt, South-eastern North Sea, based on shallow seismic (sparker and Chirp III) information

    DEFF Research Database (Denmark)

    Boldreel, Lars Ole; Kuijpers, Antoon; Madsen, Emil B

    2010-01-01

    The coastal off-shore zone of the northern part of the island of Sylt was investigated by sparker seismics and high-resolution subbottom profiling during the period 2005-2009. The data was acquired in the North Sea sector as well as in the Lister Tief, Lister Ley, Højer Dyb and Rømø Dyb. During t....... The sparker seismic and Chirp III data show that the processes responsible for the bedforms have been persistent throughout the Holocene. Based on the study, a model for the current and sedimentation regime is proposed.......The coastal off-shore zone of the northern part of the island of Sylt was investigated by sparker seismics and high-resolution subbottom profiling during the period 2005-2009. The data was acquired in the North Sea sector as well as in the Lister Tief, Lister Ley, Højer Dyb and Rømø Dyb. During...

  17. Stylobates birtlesi sp. n., a new species of carcinoecium-forming sea anemone (Cnidaria, Actiniaria, Actiniidae from eastern Australia

    Directory of Open Access Journals (Sweden)

    Andrea Crowther

    2011-04-01

    Full Text Available We describe a new species of carcinoecium-forming sea anemone, Stylobates birtlesi sp. n., from sites 680-960 m deep in the Coral Sea, off the coast of Queensland, Australia. An anemone of this genus settles on a gastropod shell inhabited by a hermit crab, then covers and extends the shell to produce a chitinous structure termed a carcinoecium. Stylobates birtlesi sp. n. is symbiotic with the hermit crab Sympagurus trispinosus (Balss, 1911. The nature of marginal sphincter muscle and nematocyst size and distribution distinguish Stylobates birtlesi sp. n. from other species in the genus. The four known species are allopatric, each inhabiting a separate ocean basin of the Indo-west Pacific. We also extend the known range of Stylobates loisetteae in the Indian Ocean off the coast of Western Australia.

  18. Incidence of lesions on Fungiidae corals in the eastern Red Sea is related to water temperature and coastal pollution

    KAUST Repository

    Furby, K.A.

    2014-07-01

    As sea surface temperatures rise and the global human population increases, large-scale field observations of marine organism health and water quality are increasingly necessary. We investigated the health of corals from the family Fungiidae using visual observations in relation to water quality and microbial biogeochemistry parameters along 1300 km of the Red Sea coast of Saudi Arabia. At large scales, incidence of lesions caused by unidentified etiology showed consistent signs, increasing significantly from the northern to southern coast and positively correlated to annual mean seawater temperatures. Lesion abundance also increased to a maximum of 96% near the populous city of Jeddah. The presence of lesioned corals in the region surrounding Jeddah was strongly correlated with elevated concentrations of ammonium and changes in microbial communities that are linked to decreased water quality. This study suggests that both high seawater temperatures and nutrient pollution may play an indirect role in the formation of lesions on corals. © 2014 Elsevier Ltd.

  19. Evaporation-precipitation changes in the eastern Arabian Sea for the last 68 ka: Implications on monsoon variability

    Digital Repository Service at National Institute of Oceanography (India)

    Govil, P.; Naidu, P.D.

    the necessary evaporation and atmospheric moisture transport during this phenomenon. Consequently, a strong link exists between ocean dynamics and the atmospheric heat and moisture transfer behind the monsoon [Shukla and Mooley, 1987; Rao and Goswami, 1988... into the Arabian Sea through numerous rivers and streams contributing to the local formation of low salinity waters with a gradient from near shore to offshore (Figure 2b). As a consequence of SW monsoon precipitation and associated river run low δ 18 Ow values...

  20. November 2009 tropical cyclone Phyan in the eastern Arabian Sea: Oceanic response along west India coast and Kavaratti lagoon

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desai, R.G.P.; Mehra, P.; VijayKumar, K.; Agarvadekar, Y.; Ryan, L.; Rivankar, P.; Viegas, B.

    with the use of an Internet-accessible real/near-real time reporting Integrated Coastal Observation Network (ICON) designed, developed and established by the National Institute of Oceanography (NIO) of India, whose output can be viewed at http...-volts batteries, which are charged through solar panels. Sea-level, Met, and surface wave parameters are acquired using dedicated Linux based data loggers and uploaded to an Internet server at 5-, 10- and 30-min intervals, respectively with the use...

  1. Re-evaluation of ‘paradox of mesozooplankton’ in the eastern Arabian Sea based on ship and satellite observations

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Madhu, N.V.; Habeebrehman, H.; Jayalakshmy, K.V.; Nair, K.K.C.; Achuthankutty, C.T.

    roles have been well recognised (Buitenhuis et al., 2006). The EAS, the western boundary of the Indian subcontinent, has several distinctive features in its plankton community compared to the rest of the Arabian Sea (Sarma, 2004). The first intensive... of phytoplankton blooms caused by coastal upwelling (Johansen et al., 1978; Haridas et al., 1980; Raj and Ramamitram, 1981; Madhupratap et al., 1990; Ashadevi et al., 2009 – unpublished; Jyothibabu et al., 2008). However, a few earlier studies have observed...

  2. Assessment of the sardine (Sardina pilchardus Walbaum, 1792 fishery in the eastern Mediterranean basin (North Aegean Sea

    Directory of Open Access Journals (Sweden)

    K. ANTONAKAKIS

    2011-06-01

    Full Text Available The aim of this study was to describe the biometric characteristics of the European sardine (Sardina pilchardus catches and assess the current status of sardine stock in North Aegean Sea based on population characteristics and abundance trends. The stock was dominated by age groups 1 and 2, not exceeding age group 4. The sardine stock in this area was assessed through an Integrated Catch-at-Age model which implements a separable Virtual Population Analysis on catch at age data with weighted tuning indices. Sardine landings data derived from the commercial purse seine fishery over the period 2000-2008 were combined with the age structure of the stock as resulted from fisheries independent acoustic surveys. Sensitivity analysis of the impact of natural mortality values on stock assessment results was applied. Additionally forecast of the sardine population parameters and catches under different exploitation scenarios was implemented in a medium term basis. Results indicated that the North Aegean Sea sardine stock is considered fully exploited with the fishery operating close but over the empirical exploitation level for sustainability. Finally, the status of the sardine stock in N. Aegean Sea is discussed in relation to the sardine stocks from the western and the central Mediterranean basin.

  3. Reconstruction of hazard-related geomorphic events from mixed-volcanoclastic sequences in the Campanian coastal area (Eastern Tyrrhenian Sea)

    Science.gov (United States)

    Violante, Crescenzo; Esposito, Eliana; Molisso, Flavia; Porfido, Sabina; Sacchi, Marco

    2010-05-01

    Sudden emplacement of large amount of pyroclastic material from explosive eruptions represents a significant interference with the geomorphic system, both for inland and coastal areas. Large volcanocalstic activity can induce sediment overburden and consequent return to the equilibrium profile by means of land degradation and erosional processes. Volcaniclastic resedimentation and generation of mass flows and floods are common phenomena affecting wide areas near the volcanic vents, occurring either soon after volcanic eruptions and during inter-eruption periods. In volcanic coastal areas volcanic debris can enter the sea in the form of avalanche deposits, hyper-concentrated flows or as the underwater continuation of subaerial flows and surges. Rapid accumulation at sea of tephra deposits from explosive eruptions can led to seafloor failure or act as weak layers for successive gravity deformations. Yet, part of volcaniclastic material can be stored in the catchments and be available for erosion a long time after an eruption. In the study area sediment availability strictly relate to massive and intermittent volcaniclastic delivery, largely responsible for aggradation/progradation of the coastal area during the Quaternary. The discussed hazard-related sedimentary features include large aprons of avalanche deposits off volcanic structures, steep sedimentary progradations at mouth of bedrock streams and small rivers, sediment re-mobilization in pro-delta areas, and shallow slides. Marine geophysical surveys and sea-land correlations led to associate such features with volcanic processes including the Mt. Epomeo uplift at Ischia island, the collapse of the Somma-Vesuvius caldera and the emplacement of pyroclastics from Phlegrean Fields and Somma-Vesuvius.

  4. Wave hindcast studies using SWAN nested in WAVEWATCH III - comparison with measured nearshore buoy data off Karwar, eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Amrutha, M.M.; SanilKumar, V.; Sandhya, K.G.; Nair, T.M.B.; Rathod, J.L.

    for the tropical Indian Ocean are 0.8 m/s, 0.57, 2.6 m/s and 52.5, respectively (Harikumar et al., 2013). The earlier studies have shown that bathymetry is also an important factor (Chawla, 2007; Brown and Wolf, 2009). Hence, both bathymetry and wind field.... J. Geophysical Res. 104 (4), 7649- 7666. Brown, Jennifer M., and Judith Wolf., 2009. Coupled wave and surge modellingfor the easern Irish sea and implications for model wind-stress. Continental shelf Res. 29(10), 1329-1342. Cavaleri, L., 1994...

  5. Comparing demersal megafaunal species diversity along the depth gradient within the South Aegean and Cretan Seas (Eastern Mediterranean).

    Science.gov (United States)

    Peristeraki, Panagiota; Tserpes, George; Lampadariou, Nikolaos; Stergiou, Kostantinos I

    2017-01-01

    Knowledge on biodiversity patterns of demersal megafaunal species in the Mediterranean and particularly in its eastern basin is still very scarce. In the present study, fine-scale diversity patterns in relation to depth were analyzed for three major megafaunal groups (fish, cephalopods and crustaceans) in three subareas of the eastern Mediterranean (Crete, Cyclades and Dodecanese islands). The analysis was based on data from the Mediterranean International Trawl Survey conducted during 2005-2014 and the relationship between depth and two different diversity measures (species richness and Shannon-Weaver) was examined using Generalized Additive Modeling (GAM) techniques. Species richness of fish decreased with depth in two of the three subareas (Cyclades, Dodecanese), while the opposite was true for crustaceans in all subareas. Cephalopods had higher species richness at intermediate depths, near the shelf break. Significant differences among subareas were found, with Crete showing a distinct species richness-depth pattern, which was more obvious for fish and cephalopods. The differences among subareas were also highlighted based on the occurrence of alien species of Indo-Pacific origin, which were more frequent in Crete. Our results suggested that the importance of depth-related factors in structuring communities was higher for cephalopods and less important for fish, and that Crete showed a distinct diversity-depth relationship, a fact that can be attributed to its specific geographical and oceanographic characteristics. These results support the current GFCM/FAO's characterization of Crete as a unique geographic subarea. The findings of the study contribute to understanding the causes of underlying diversity patterns and would assist various environmental management actions, particularly those related to the establishment of marine-protected areas.

  6. Live (Rose-bengal stained) foraminifera from deep-sea anoxic salt brine in the Eastern Mediterranean: toward understanding limit of life for single-celled eukaryotes (foraminifera)

    Science.gov (United States)

    Kitazato, H.; Ohkawara, N.; Iwasaki, A.; Nomaki, H.; Akoumianaki, I.; Tokuyama, H.

    2012-04-01

    What is a limit of life for the eukaryotes? Eukaryotes are thought to adapt and evolve under oxic environmental conditions. Recently, there are many exceptions for this hypothesis, as many eukaryotes including metazoan groups are found in anoxic environmental conditions. We found many rose-bengal stained foraminifera from a deep-hypersaline anoxic basin (DHAB) in the eastern Mediterranean. During KH06-04 cruise, we conducted oceanographic research at Medée Lake, the largest DHAB, that is located 100km southwest of Crete Island in the eastern Mediterranean. The lake situates at 2920m in water depth. Depth of saline water is 120m in maximum. Both water and sediment samplings were carried out both with Niskin bottles and multiple corer attached to camera watching sampling system at three sites, inside of the lake (CS), the edge of the lake (OMS) and the normal deep-sea floor (RS). Temperature, salinity, and dissolved oxygen concentrations at central saline lake are 15.27 oC, 328PSU, and 0.0 ml/L, respectively. Strong smell of hydrogen sulfide was detected from the lake sediment. Subsamples were conducted for multiple core samples using 3 subcores(φ 2.9cm) from each core tube (φ 8.2cm). Sediment samples were fixed with 4% formalin Rose Bengal solution on board. In laboratory, samples were washed with 32μm sieve. Rose Bengal stained specimens were picked under binocular stereomicroscope (Zeiss Stemi SV11) for surface 0.5cm layer, and identified with inverted microscope (Nikon ECLIPSE TE300). In total, 26 species belonging to 9 genera were identified from three sites. Six species belonging to two genera were identified in the center of the salt brine. Only a few species are common among three sites, even though the numbers of common species were 10 between OMS and RS sites. In DHAB, spherical organic-walled species, such as allogromiid and psammosphaerid, are dominant. In contrast, tube-like chitinous foraminifera, such as Resigella, Conicotheca and Nodellum, are

  7. Understanding Abrupt, Natural Climate Variability Post-Industrial Revolution from the Subtropical Eastern Pacific: A Novel High Resolution Alkenone-derived Sea Surface Temperature Record

    Science.gov (United States)

    Kelly, C. S.; O'Mara, N. A.; Herbert, T.; Abella-Gutiérrez, J. L.; Herguera, J. C.

    2015-12-01

    Despite the ocean's importance in global biogeochemical feedbacks and heat storage, there is still a paucity of decadally-resolved sea surface temperature (SST) records to complement lacustrine and dendrological records of recent paleoclimate. Natural climate variability on multidecadal timescales is dominated by internal ocean circulation dynamics and feedbacks, and it is therefore imperative to employ marine proxies to reconstruct high resolution climate change. The timescales of this ocean-induced natural climate variability can be broken down into a few characteristic climate modes. Pressing questions about these modes include their stationarity in frequency and amplitude over time, in addition to the hypothesis that anthropogenic climate change has altered their behavior in comparison to natural variability. To pursue these questions, we must discern and analyze suitable climate archives in regions where modes of interest dominate modern climate variability. The region of Baja California, Mexico exhibits exceptional teleconnection to the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Local, dramatic effects of ENSO and PDO on the marine biology and economy underline the importance of regional paleoclimate records from the Baja peninsula. Here, we present a high-resolution alkenone-derived SST reconstruction from the Industrial Revolution through the year 2000 by analysis of laminated box and Kasten sediment cores at Site PCM 00-78 (25.18°N, 112.66°W) in the subtropical eastern Pacific at a depth of 540 meters. Our SST record corresponds with NOAA extended reconstructed sea surface temperature, providing a robust basis for organic geochemical marine climatic reconstructions on timescales usually accessible only through speleothems, coral density bands, tree rings, and the like. Accordingly, based on this comparison to the historical data we expect our SST record may provide a more robust record of inter and multidecadal

  8. Structural Evolution of the India-Arabia Plate Boundary from Miocene to Present-Day (NW Indian Ocean) and Comparison with the Dead Sea Fault (Eastern Mediterranean Sea).

    Science.gov (United States)

    Rodriguez, M.; Huchon, P.; Chamot Rooke, N.; Fournier, M.; Delescluse, M.; Ben Avraham, Z.; Ten Brink, U. S.

    2014-12-01

    Arabia is bounded by the Dead Sea Transform (DST) to the west and by the Owen Fracture Zone (OFZ) to the east. These present-day major strike-slip fault systems activated during the Plio-Pleistocene, which contrasts with the age of inception of strike-slip motion, assumed to begin around 13-18 Ma for the DST and around 20 Ma at the edge of the Owen-Murray Ridge (OMR) for the India-Arabia plate boundary. This discrepancy between the age of the active strike-slip systems and the age of inception of strike-slip motion raises the question of the kinematic driver for the transition between successive generations of strike-slip faults. Using a recent mutibeam and seismic dataset crossing the OFZ and the OMR, we provide a new geodynamic framework for the Miocene to present-day structural evolution of the India-Arabia plate boundary, and highlight some similarities with the structural evolution of the DST. We first document a Late Miocene episode of uplift of the OMR uplift along the Miocene India-Arabia plate boundary. The onset of this uplift is coeval with a plate reorganization event marked by the onset of intra-plate deformation in the Central Indian Ocean. The OFZ emplaced around 3 Ma, with major pull-apart basins opening (20°N Basin, Dalrymple Trough) dated at 2.4 Ma by far-field correlation with ODP Sites. The opening of pull-apart basins is coeval with the last structural reorganization of the Makran accretionnary wedge, marked by the regional M-unconformity, and with a major intensification of the Indian monsoon. A Late Miocene episode of folding is also recognized at the Lebanon ranges prior to the onset of the present-day DST, which occurred in the Late Pliocene-Early Pleistocene. The similarities between the geological history of the India-Arabia plate boundary and the DST in the Late Miocene and the Late Pliocene-Early Pleistocene suggest that both plate boundaries recorded the same kinematic changes. Late Miocene (i.e. Tortonian) deformation is widely

  9. Observations of the aerosol particle number concentration in the marine boundary layer over the south-eastern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Dalia Jasinevičiene

    2013-08-01

    Full Text Available Continuous measurements of the aerosol particle number concentration (PNCin the size range from 4.5 nm to 2 µm were performed at the Preila marine background site during 2008–2009.The concentration maxima in summer was twice the average (2650±50 cm-3. A trajectory-based approach was applied for source identification. Potential Source Contribution Function (PSCFanalysis was performed to estimate the possible contribution of long-range andlocal PNC transport to PNC concentrations recorded at the marine backgroundsite. The PSCF results showed that the marine boundary layer was not seriouslyaffected by long-range transport, but that local transport of air pollutionwas recognized as an important factor. North Atlantic and Sea-Marine typeclusters respectively represented 32.1% and 17.9% of the total PNC spectraand were characterized by the lowest PNCs (1080±1340 and 1210±1040 cm-3 respectively among all clusters.   Wavelet transformation analysis of 1-h aerosol PNC indicated that whilethe 16-h scale was a constant feature of aerosol PNC evolution in spring, the longer (∼60-h scalesappeared mainly over the whole year (except June. Principal componentanalysis (PCA revealed a strong correlation between PNC and NaCl,highlighting the influence of sea-salt aerosols. In addition, PCA also showedthat PNC depended on optical and meteorological parameters such as UVR andtemperature.

  10. Biology of a deep-water sea anemone (Anthozoa: Actiniidae) from eastern Canada: Spawning, development, and growth

    Science.gov (United States)

    Mercier, Annie; Baillon, Sandrine; Daly, Marymegan; Macrander, Jason; Hamel, Jean-François

    2017-03-01

    Knowledge of the general biology and reproductive ecology of deep-water species can help predict their resilience to environmental and anthropogenic disturbances. The present study centers on live specimens of a deep-water sea anemone which were collected at bathyal depths between 1100 and 1400 m and kept in a mesocosm for over 6 years. Morphology and DNA sequencing confirmed that the species belongs to the genus Urticina. Male and female (9-10 cm pedal disk diameter, 90 tentacles) spawned 4 years post collection, in early spring (March). Both sexes released gametes through the mouth. The negatively buoyant oocytes (550-600 μm in diameter) quickly settled on the rocks and soft sediments surrounding the female. Lecithotrophic embryonic and larval development occurred on the substratum. Fully developed planula larvae were detected after 17-21 days. Planulae started to crawl and swim around but remained demersal. Metamorphosis and settlement occurred after 30-35 days, exclusively on hard substrata and preferentially on undersurfaces. Offspring grew slowly, developing 8 tentacles after 5 months and 24 tentacles after 12 months (3-4 mm pedal disk diameter). After 2.6 years of growth, the captive-born sea anemones reached 12-16 mm in pedal disk diameter and possessed 48-54 tentacles.

  11. Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific.

    Science.gov (United States)

    Raverty, Stephen A; Rhodes, Linda D; Zabek, Erin; Eshghi, Azad; Cameron, Caroline E; Hanson, M Bradley; Schroeder, J Pete

    2017-03-24

    In the Salish Sea, the endangered Southern Resident Killer Whale (SRKW) is a high trophic indicator of ecosystem health. Three major threats have been identified for this population: reduced prey availability, anthropogenic contaminants, and marine vessel disturbances. These perturbations can culminate in significant morbidity and mortality, usually associated with secondary infections that have a predilection to the respiratory system. To characterize the composition of the respiratory microbiota and identify recognized pathogens of SRKW, exhaled breath samples were collected between 2006-2009 and analyzed for bacteria, fungi and viruses using (1) culture-dependent, targeted PCR-based methodologies and (2) taxonomically broad, non-culture dependent PCR-based methodologies. Results were compared with sea surface microlayer (SML) samples to characterize the respective microbial constituents. An array of bacteria and fungi in breath and SML samples were identified, as well as microorganisms that exhibited resistance to multiple antimicrobial agents. The SML microbes and respiratory microbiota carry a pathogenic risk which we propose as an additional, fourth putative stressor (pathogens), which may adversely impact the endangered SRKW population.

  12. Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the Southern Cretan margin, Eastern Mediterranean Sea: a baseline assessment.

    Science.gov (United States)

    Mandalakis, Manolis; Polymenakou, Paraskevi N; Tselepides, Anastasios; Lampadariou, Nikolaos

    2014-07-01

    Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (ΣAH:326-3758ngg(-1), dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (ΣPAH:9-60ngg(-1)). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg(-1)), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg(-1)) and polychlorinated biphenyls (ΣPCB:38-1182pgg(-1)) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Gonad and gut indices of European Sea Urchin (Paracentrotus lividus, L, 1816 in Çesme Bay of Eastern Agean Sea

    Directory of Open Access Journals (Sweden)

    Aysun Küçükdermenci

    2016-01-01

    Full Text Available The objective of present study is to determine the gut and gonad yield of Paracentrotus lividus populations occuring along Aegean Sea coastline and to evaluate of the environmental conditions on the gonad indices variability. To achieve this, samples were gathered during twelve months and biometric measurements were done. The wet gonad index peaked (6.22±0.56 % in one (April-14°C of the coldest months (between November-May even though water temperature was not change so much between November and May. It is determined that decreasing temperature affected gonad production but temperature is not only one factor effecting of gonad because of gonad indices were not high during the other cold months (between November-May in this study. The higher gut index (GII values were observed between January (6.31±0.71 % and May (6.07±0.70 %. The gut index was higher in spring than in fall in this study.

  14. How a collaborative integrated taxonomic effort has trained new spongiologists and improved knowledge of Martinique Island (French Antilles, eastern Caribbean Sea) marine biodiversity.

    Science.gov (United States)

    Pérez, Thierry; Díaz, Maria-Cristina; Ruiz, César; Cóndor-Luján, Baslavi; Klautau, Michelle; Hajdu, Eduardo; Lobo-Hajdu, Gisele; Zea, Sven; Pomponi, Shirley A; Thacker, Robert W; Carteron, Sophie; Tollu, Guillaume; Pouget-Cuvelier, Adeline; Thélamon, Philippe; Marechal, Jean-Philippe; Thomas, Olivier P; Ereskovsky, Alexander V; Vacelet, Jean; Boury-Esnault, Nicole

    2017-01-01

    Although sponges are important components of benthic ecosystems of the Caribbean Sea, their diversity remained poorly investigated in the Lesser Antilles. By organizing a training course in Martinique, we wanted both to promote taxonomy and to provide a first inventory of the sponge diversity on this island. The course was like a naturalist expedition, with a field laboratory and a classroom nearby. Early-career scientists and environmental managers were trained in sponge taxonomy. We gathered unpublished data and conducted an inventory at 13 coastal sites. We explored only shallow water habitats (0-30 m), such as mangroves, reefs or rocky bottoms and underwater caves. According to this study, the sponge fauna of Martinique is currently represented by a minimum of 191 species, 134 of which we could assign species names. One third of the remaining non-identified sponge species we consider to be new to science. Martinique appears very remarkable because of its littoral marine fauna harboring sponge aggregations with high biomass and species diversity dominating over coral species. In mangroves, sponges cover about 10% of the surface of subtidal roots. Several submarine caves are true reservoirs of hidden and insufficiently described sponge diversity. Thanks to this new collaborative effort, the Eastern Caribbean has gained a significant increase of knowledge, with sponge diversity of this area potentially representing 40% of the total in the Caribbean Sea. We thus demonstrated the importance of developing exploratory and educational research in areas historically devoid of biodiversity inventories and systematics studies. Finally, we believe in the necessity to consider not only the number of species but their distribution in space to evaluate their putative contribution to ecosystem services and our willingness to preserve them.

  15. How a collaborative integrated taxonomic effort has trained new spongiologists and improved knowledge of Martinique Island (French Antilles, eastern Caribbean Sea) marine biodiversity

    Science.gov (United States)

    2017-01-01

    Although sponges are important components of benthic ecosystems of the Caribbean Sea, their diversity remained poorly investigated in the Lesser Antilles. By organizing a training course in Martinique, we wanted both to promote taxonomy and to provide a first inventory of the sponge diversity on this island. The course was like a naturalist expedition, with a field laboratory and a classroom nearby. Early-career scientists and environmental managers were trained in sponge taxonomy. We gathered unpublished data and conducted an inventory at 13 coastal sites. We explored only shallow water habitats (0–30 m), such as mangroves, reefs or rocky bottoms and underwater caves. According to this study, the sponge fauna of Martinique is currently represented by a minimum of 191 species, 134 of which we could assign species names. One third of the remaining non-identified sponge species we consider to be new to science. Martinique appears very remarkable because of its littoral marine fauna harboring sponge aggregations with high biomass and species diversity dominating over coral species. In mangroves, sponges cover about 10% of the surface of subtidal roots. Several submarine caves are true reservoirs of hidden and insufficiently described sponge diversity. Thanks to this new collaborative effort, the Eastern Caribbean has gained a significant increase of knowledge, with sponge diversity of this area potentially representing 40% of the total in the Caribbean Sea. We thus demonstrated the importance of developing exploratory and educational research in areas historically devoid of biodiversity inventories and systematics studies. Finally, we believe in the necessity to consider not only the number of species but their distribution in space to evaluate their putative contribution to ecosystem services and our willingness to preserve them. PMID:28329020

  16. Sinkholes, subsidence and subrosion on the eastern shore of the Dead Sea as revealed by a close-range photogrammetric survey

    Science.gov (United States)

    Al-Halbouni, Djamil; Holohan, Eoghan P.; Saberi, Leila; Alrshdan, Hussam; Sawarieh, Ali; Closson, Damien; Walter, Thomas R.; Dahm, Torsten

    2017-05-01

    Ground subsidence and sinkhole collapse are phenomena affecting regions of karst geology worldwide. The rapid development of such phenomena around the Dead Sea in the last four decades poses a major geological hazard to the local population, agriculture and industry. Nonetheless many aspects of this hazard are still incompletely described and understood, especially on the eastern Dead Sea shore. In this work, we present a first low altitude (digital surface model (5 cm px-1) and orthophoto of this area (2.1 km2). We also outline the factors affecting the quality and accuracy of this approach. Our analysis reveals a kilometer-scale sinuous depression bound partly by flexure and partly by non-tectonic faults. The estimated minimum volume loss of this subsided zone is 1.83 ṡ 106 m3 with an average subsidence rate of 0.21 m yr-1 over the last 25 years. Sinkholes in the surveyed area are localized mainly within this depression. The sinkholes are commonly elliptically shaped (mean eccentricity 1.31) and clustered (nearest neighbor ratio 0.69). Their morphologies and orientations depend on the type of sediment they form in: in mud, sinkholes have a low depth to diameter ratio (0.14) and a long-axis azimuth of NNE-NE. In alluvium, sinkholes have a higher ratio (0.4) and are orientated NNW-N. From field work, we identify actively evolving artesian springs and channelized, sediment-laden groundwater flows that appear locally in the main depression. Consequently, subrosion, i.e. subsurface mechanical erosion, is identified as a key physical process, in addition to dissolution, behind the subsidence and sinkhole hazard. Furthermore, satellite image analysis links the development of the sinuous depression and sinkhole formation at Ghor Al-Haditha to preferential groundwater flow paths along ancient and current wadi riverbeds.

  17. How a collaborative integrated taxonomic effort has trained new spongiologists and improved knowledge of Martinique Island (French Antilles, eastern Caribbean Sea marine biodiversity.

    Directory of Open Access Journals (Sweden)

    Thierry Pérez

    Full Text Available Although sponges are important components of benthic ecosystems of the Caribbean Sea, their diversity remained poorly investigated in the Lesser Antilles. By organizing a training course in Martinique, we wanted both to promote taxonomy and to provide a first inventory of the sponge diversity on this island. The course was like a naturalist expedition, with a field laboratory and a classroom nearby. Early-career scientists and environmental managers were trained in sponge taxonomy. We gathered unpublished data and conducted an inventory at 13 coastal sites. We explored only shallow water habitats (0-30 m, such as mangroves, reefs or rocky bottoms and underwater caves. According to this study, the sponge fauna of Martinique is currently represented by a minimum of 191 species, 134 of which we could assign species names. One third of the remaining non-identified sponge species we consider to be new to science. Martinique appears very remarkable because of its littoral marine fauna harboring sponge aggregations with high biomass and species diversity dominating over coral species. In mangroves, sponges cover about 10% of the surface of subtidal roots. Several submarine caves are true reservoirs of hidden and insufficiently described sponge diversity. Thanks to this new collaborative effort, the Eastern Caribbean has gained a significant increase of knowledge, with sponge diversity of this area potentially representing 40% of the total in the Caribbean Sea. We thus demonstrated the importance of developing exploratory and educational research in areas historically devoid of biodiversity inventories and systematics studies. Finally, we believe in the necessity to consider not only the number of species but their distribution in space to evaluate their putative contribution to ecosystem services and our willingness to preserve them.

  18. Millennial-scale sea surface temperature changes in the eastern Mediterranean (Nile River Delta region) over the last 27,000 years

    Science.gov (United States)

    Castañeda, Isla S.; Schefuß, Enno; Pätzold, Jürgen; Sinninghe Damsté, Jaap S.; Weldeab, Syee; Schouten, Stefan

    2010-03-01

    In this study we utilize two organic geochemical proxies, the U37k‧ index and TEX86, to examine past sea surface temperatures (SST) from a site located near the Nile River Delta in the eastern Mediterranean (EM) Sea. The U37k‧ and TEX86 records generally are in agreement and indicate SST ranges of 14°C-26°C and 14°C-28°C, respectively, during the last 27 cal ka. During the Holocene, TEX86-based SST estimates are usually higher than U37k‧-based SST estimates, which is likely due to seasonal differences between the timing of the haptophyte and crenarchaeota blooms in the EM and is related to the onset of the modern flow regime of the Nile River. Both records show that SST varied on centennial to millennial timescales in response to global climate events, i.e., cooling during the Last Glacial Maximum (LGM), Heinrich event 1 (H1), and the Younger Dryas (YD) and warming during the Bølling-Allerød and in the early Holocene during deposition of sapropel S1. The H1 cooling was particularly severe and is marked by a drop in SST of ˜4.5°C in comparison to pre-H1 SST, with temperatures >1°C cooler than during the LGM. In contrast to high-latitude and western Mediterranean records, which indicate both an abrupt onset and termination of the YD event, the transition from the YD to the Holocene was much more gradual in the EM.

  19. Spatio-temporal variation of microphytoplankton in the upwelling system of the south-eastern Arabian Sea during the summer monsoon of 2009

    Directory of Open Access Journals (Sweden)

    Lathika Cicily Thomas

    2013-02-01

    Full Text Available The phytoplankton standing crop was assessed in detail along the South Eastern Arabian Sea (SEAS during the different phases of coastal upwelling in 2009. During phase 1 intense upwelling was observed along the southern transects(8°N and 8.5°N. The maximum chlorophyll a concentration (22.7 mg m-3 was observedin the coastal waters off Thiruvananthapuram (8.5°N. Further north there was no signature of upwelling, with extensive Trichodesmium erythraeum blooms. Diatoms dominated in these upwelling regions with thecentric diatom Chaetoceros curvisetus being the dominant species along the 8°N transect. Along the 8.5°N transect pennate diatoms like Nitzschia seriata and Pseudo-nitzschia sp. dominated. Duringphase 2, upwelling of varying intensity was observed throughout the study area with maximum chlorophyll a concentrations along the 9°N transect (25 mg m-3 with Chaetoceros curvisetus as the dominantphytoplankton. Along the 8.5°N transect pennate diatoms during phase 1 were replaced by centric diatoms like Chaetoceros sp. The presence of solitary pennate diatoms Amphora sp. and Navicula sp.were significant in the waters off Kochi. Upwelling was waning during phase 3 and was confined to the coastal waters of the southern transects with the highest chlorophyll a concentration of 11.2 mg m-3. Along withdiatoms, dinoflagellate cell densities increased in phases 2 and 3. In the northern transects (9°N and 10°N the proportion of dinoflagellates was comparatively higher and was represented mainly by Protoperidinium spp.

  20. Neogene Tectonics of Part of the Junction of Cyprus and Hellenic Arcs in the Eastern Mediterranean Sea

    Science.gov (United States)

    Küçük, H. M.; Dondurur, D.; ćifçi, G.; Gürçay, S.; Hall, J.; Yaltırak, C.; Aksu, A. E.

    2012-04-01

    The junction between the Hellenic and Cyprus Arcs is one of the tectonically most active regions of the eastern Mediterranean. This junction developed in association with convergence between the African and Eurasian Plates, and the re-organization of the smaller Aegean-Anatolian and Arabian Microplates. Recent studies have shown that the predominant Miocene deformation process in the eastern Mediterranean is compressional tectonism. However, many studies have also shown that the strain is partitioned in the Pliocene-Quaternary and the area displays regions dominated by compression, strike slip and extensional tectonism. The junction between the Hellenic and Cyprus Arcs exhibits complex morphological features including submarine mountains, rises, ridges and trenches. Approximately 600 km of high resolution 72-channel seismic profiles were collected from the junction of Cyprus and Hellenic Arcs using a 450 m long 6.25 m hydrophone spacing streamer and a seven gun array with a 200 cubic inch total volume. This project was part of the joint scientific venture between Dokuz Eylül University (Turkey) and Memorial University of Newfoundland (Canada), and was funded by TÜBITAK and NSERC. The study area includes the southwestern Antalya Basin and the Anaxagoras Mountain of the larger Anaximander Mountains. The multichannel data were processed both at Dokuz Eylül and Memorial University of Newfoundland, using the Landmark Graphics ProMAX software, with automatic gain control, short-gap deconvolution, velocity analysis, normal move-out correction, stack, filter (typically 50-200 Hz bandpass), f-k time migration, and adjacent trace sum. Despite the fact that the source volume was modest, reflections are imaged to 2-3 s two-way time below seabed, even in 2 km water depth. The processed seismic reflection profiles show that there are three distinct sedimentary units, separated by two prominent markers: the M-reflector separates the Pliocene-Quaternary from the underlying

  1. Temperature profiles from mechanical bathythermograph (MBT) casts from the USS WARBLER in the Eastern China Sea and other locations in support of the Fleet Observations of Oceanographic Data (FLOOD) project from 19 September 1966 to 27 September 1966 (NODC Accession 6600396)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MBT data were collected from the USS WARBLER in support of the Fleet Observations of Oceanographic Data (FLOOD) project. Data were collected in the Eastern China Sea...

  2. A STUDY ON THE HENDIADYOINS IN THE EASTERN BLACK-SEA REGION DIALECTS / ORTA VE DOĞU KARADENIZ AĞIZLARINDA GÖRÜLEN IKILEMELER ÜZERINE BIR DEĞERLENDIRME

    Directory of Open Access Journals (Sweden)

    Dr. Ercan ALKAYA

    2008-08-01

    Full Text Available In this study, the hendiadyoins of the dialects of the Central andEastern Black-Sea Region such as Ordu, Giresun, Rize and Trabzon whichcan be observed as non-literary usages are dealt with. The hendiadyoins takenfrom the dialect studies on the afore-mentioned dialects and from theDerleme Sözlüğü are assessed in respect with their origins, structures andmeanings.

  3. Assimilation of the seabird and ship drift data in the north-eastern sea of Japan into an operational ocean nowcast/forecast system

    Science.gov (United States)

    Miyazawa, Yasumasa; Guo, Xinyu; Varlamov, Sergey M.; Miyama, Toru; Yoda, Ken; Sato, Katsufumi; Kano, Toshiyuki; Sato, Keiji

    2015-01-01

    At the present time, ocean current is being operationally monitored mainly by combined use of numerical ocean nowcast/forecast models and satellite remote sensing data. Improvement in the accuracy of the ocean current nowcast/forecast requires additional measurements with higher spatial and temporal resolution as expected from the current observation network. Here we show feasibility of assimilating high-resolution seabird and ship drift data into an operational ocean forecast system. Data assimilation of geostrophic current contained in the observed drift leads to refinement in the gyre mode events of the Tsugaru warm current in the north-eastern sea of Japan represented by the model. Fitting the observed drift to the model depends on ability of the drift representing geostrophic current compared to that representing directly wind driven components. A preferable horizontal scale of 50 km indicated for the seabird drift data assimilation implies their capability of capturing eddies with smaller horizontal scale than the minimum scale of 100 km resolved by the satellite altimetry. The present study actually demonstrates that transdisciplinary approaches combining bio-/ship- logging and numerical modeling could be effective for enhancement in monitoring the ocean current. PMID:26633309

  4. Tree species diversity and its relationship to stand parameters and geomorphology features in the eastern Black Sea region forests of Turkey.

    Science.gov (United States)

    Ozcelik, Ramazan; Gul, Altay Ugur; Merganic, Jan; Merganicova, Katarina

    2008-05-01

    We studied the effects of stand parameters (crown closure, basal area, stand volume, age, mean stand diameter number of trees, and heterogeneity index) and geomorphology features (elevation, aspect and slope) on tree species diversity in an example of untreated natural mixed forest stands in the eastern Black Sea region of Turkey. Tree species diversity and basal area heterogeneity in forest ecosystems are quantified using the Shannon-Weaver and Simpson indices. The relationship between tree species diversity basal area heterogeneity stand parameters and geomorphology features are examined using regression analysis. Our work revealed that the relationship between tree species diversity and stand parameters is loose with a correlation coefficient between 0.02 and 0.70. The correlation of basal area heterogeneity with stand parameters fluctuated between 0.004 and 0.77 (R2). According to our results, stands with higher tree species diversity are characterised by higher mean stand diameter number of diameter classes, basal area and lower homogeneity index value. Considering the effect of geomorphology features on tree species or basal area heterogeneity we found that all investigated relationships are loose with R < or = 0.24. A significant correlation was detected only between tree species diversity and aspect. Future work is required to verify the detected trends in behaviour of tree species diversity if it is to estimate from the usual forest stand parameters and topography characteristics.

  5. Assimilation of the seabird and ship drift data in the north-eastern sea of Japan into an operational ocean nowcast/forecast system.

    Science.gov (United States)

    Miyazawa, Yasumasa; Guo, Xinyu; Varlamov, Sergey M; Miyama, Toru; Yoda, Ken; Sato, Katsufumi; Kano, Toshiyuki; Sato, Keiji

    2015-12-03

    At the present time, ocean current is being operationally monitored mainly by combined use of numerical ocean nowcast/forecast models and satellite remote sensing data. Improvement in the accuracy of the ocean current nowcast/forecast requires additional measurements with higher spatial and temporal resolution as expected from the current observation network. Here we show feasibility of assimilating high-resolution seabird and ship drift data into an operational ocean forecast system. Data assimilation of geostrophic current contained in the observed drift leads to refinement in the gyre mode events of the Tsugaru warm current in the north-eastern sea of Japan represented by the model. Fitting the observed drift to the model depends on ability of the drift representing geostrophic current compared to that representing directly wind driven components. A preferable horizontal scale of 50 km indicated for the seabird drift data assimilation implies their capability of capturing eddies with smaller horizontal scale than the minimum scale of 100 km resolved by the satellite altimetry. The present study actually demonstrates that transdisciplinary approaches combining bio-/ship- logging and numerical modeling could be effective for enhancement in monitoring the ocean current.

  6. Catch composition, reproductive biology and diet of the bramble shark Echinorhinus brucus (Squaliformes: Echinorhinidae) from the south-eastern Arabian Sea.

    Science.gov (United States)

    Akhilesh, K V; Bineesh, K K; White, W T; Shanis, C P R; Hashim, M; Ganga, U; Pillai, N G K

    2013-11-01

    Fishery and biological data are presented for the poorly known bramble shark Echinorhinus brucus (Squaliformes: Echinorhinidae), from the deep waters of the south-eastern Arabian Sea. A total of 5318 individuals from by-catch landings of deep-water bottom set longlines, gillnets and shrimp trawl fisheries operating at depths of 200-1200 m were recorded between January 2008 and December 2011 at the Kochi Fisheries Harbour (Kerala). A total of 431 individuals, from 46 to 318 cm total length (L(T)) and 0·8 to 132 kg total mass (M(T)), were examined to determine biological data for this species. The LT at which 50% were mature (L(T)50) for females and males was estimated at 189 and 187 cm LT. Litter size ranged from 10 to 36 and size at birth was between 42 and 46 cm L(T). Dietary analysis of stomach contents revealed E. brucus feeds on a variety of prey including crustaceans (69% index of relative importance, I(RI)), teleosts (25·8% I(RI)), cephalopods (1·7% I(RI)) and elasmobranchs (0·7% I(RI)). This study provides the first detailed biological data for this species and also highlights the extent of the by-catch fishery for this species in Indian waters. © 2013 The Fisheries Society of the British Isles.

  7. Surface Water pCO2 Variations and Sea-Air CO2 Fluxes During Summer in the Eastern Canadian Arctic

    Science.gov (United States)

    Burgers, T. M.; Miller, L. A.; Thomas, H.; Else, B. G. T.; Gosselin, M.; Papakyriakou, T.

    2017-12-01

    Based on a 2 year data set, the eastern Canadian Arctic Archipelago and Baffin Bay appear to be a modest summertime sink of atmospheric CO2. We measured surface water CO2 partial pressure (pCO2), salinity, and temperature throughout northern Baffin Bay, Nares Strait, and Lancaster Sound from the CCGS Amundsen during its 2013 and 2014 summer cruises. Surface water pCO2 displayed considerable variability (144-364 μatm) but never exceeded atmospheric concentrations, and average calculated CO2 fluxes in 2013 and 2014 were -12 and -3 mmol C m-2 d-1 (into the ocean), respectively. Ancillary measurements of chlorophyll a reveal low summertime productivity in surface waters. Based on total alkalinity and stable oxygen isotopes (δ18O) data, a strong riverine signal in northern Nares Strait coincided with relatively high surface pCO2, whereas areas of sea-ice melt occur with low surface pCO2. Further assessments, extending the seasonal observation period, are needed to properly constrain both seasonal and annual CO2 fluxes in this region.

  8. Restructuring of Turkey's electricity market and the share of hydropower energy: The case of the Eastern Black Sea Basin

    Energy Technology Data Exchange (ETDEWEB)

    Uzlu, Ergun; Koemuercue, Murat ihsan [Karadeniz Technical University, Civil Engineering Department, 61080 Trabzon (Turkey); Akpinar, Adem [Guemueshane University, Civil Engineering Department, 29000 Guemueshane (Turkey)

    2011-02-15

    This paper presents the historical development of Turkey's electricity power sector, the efforts for introducing competition in the power industry in Turkey, and the concerns regarding restructuring in Turkey. The contribution of the hydropower energy potential in Turkey to the reconstruction of the electricity structure in Turkey is also investigated. Then, among the 25 hydrological basins in Turkey, the Eastern Black Sea Basin located in the northeast of Turkey, which has great advantages from the view point of small hydropower potential or hydropower potential without storage, is chosen as the case study to carry out some investigations concerning its potential and to analyze the contribution of the private sector (the corporate body) in regard to the development of hydro potential in this basin within the scope of the 4628 Electricity Market Law. With this law, concerning the restructuring of the electricity market, private sector investments in this segment have increased. In total, 1524 hydroelectric power projects with 22 360 MW installed capacity has been implemented until January 22nd, 2009 and this figure is continuously rising. (author)

  9. Raised marine sequences of Lanzarote and Fuerteventura revisited—a reappraisal of relative sea-level changes and vertical movements in the eastern Canary Islands during the Quaternary

    Science.gov (United States)

    Zazo, Cari; Goy, José Luis; Hillaire-Marcel, Claude; Gillot, Pierre-Yves; Soler, Vicente; González, José Ángel; Dabrio, Cristino J.; Ghaleb, Bassam

    2002-10-01

    Systematic mapping and morphosedimentary analysis of Fuerteventura and Lanzarote Islands supported by laboratory techniques (U-series mostly by TIMS, 14C analysis and allo-isoleucine measurements on biogenic carbonates from raised marine deposits, paleomagnetic and a few K/Ar measurements on volcanic formations related to marine deposits) provide a basis for constraining the age of Late Cainozoic marine units. The most complete sequences of raised marine terraces are found at similar elevations in both islands. They include up to 12 marine terraces (Episodes) at elevations between 0 m and 70 m above mean sea level (asl). At least six terraces should be of Quaternary age, and more recent than 1.2 Myr. Throughout the whole marine sequence with the exception of the Holocene terrace, the warm fauna assemblage is characterized by the presence of Ostrea virleti, Nerita emiliana, and Strombus ( S. cf. coronatus-S. cf. bubonius). However, there is a major change, highlighted by the disappearance of the first two species, below the 8-10 m terrace, that could possibly correspond to MIS 11. K-Ar measurements allow an estimate for mean uplift rate of 1.7 cm/ka during the last million years. The present elevation of the Last Interglacial deposits (about 1 and 2 m asl) shows discontinuous vertical movements with possibly a reverse trend since MIS 9 in eastern Canary Islands.

  10. Temporal changes in Quaternary paleoenvironment and ostracode fauna in the eastern Indian Sea off Western Australia (IODP, Exp. 356, site U1461)

    Science.gov (United States)

    Iwatani, H.; Yasuhara, M.; Angue Minto'O, C. M.; Bassetti, M. A.; Expedition 356 Scientists, I.

    2016-12-01

    The International Ocean Discovery Program Expedition 356 drilled on seven sites off Western Australia to reveal the history of the Indonesian throughflow, the effects of the Australian monsoon, and the subsidence of the northwest shelf of Australia. To achieve these objectives, we investigated paleoenvironmental evolutions in this region during the Quaternary period using high-resolution statistical analyses of the fossil Ostracoda (Crustacea) as an effective environmental indicator. For the investigation, we used a sediment core obtained from an area off Western Australia in the eastern Indian Sea (site: U1461; water depth: 128 m; latitude: 20°, 12.85' S; longitude: 115°, 03.94' E). The upper part of the core mainly comprises alternating beds of darker-colored packstone/wackestone and light-colored wackestone/mudstone. The light-colored wackestone/mudstone beds often contain fecal pellets and well-preserved molluscan fossils. We investigated fossil ostracode faunal composition and species diversity changes during the deposition of the study site. Many well-preserved ostracodes were recorded in the studied cores. Many of collected species are extant taxa that inhabit the upper sublittoral regions as reported from around the recent Indian Ocean off northwestern Australia. Ostracode assemblages, abundance, and diversity drastically changed during the deposition, and they are concordant with sedimentary facies. Here we will discuss the relationships between these paleo-communities changes and paleoenvironmental conditions.

  11. Geochemistry of the Adige River water from the Eastern Alps to the Adriatic Sea (Italy): evidences for distinct hydrological components and water-rock interactions.

    Science.gov (United States)

    Natali, C; Bianchini, G; Marchina, C; Knöller, K

    2016-06-01

    The Adige River flows from the Eastern Alps to the Adriatic Sea and the understanding of its fluvial dynamics can be improved by geochemical and O-H isotopic investigation. The most negative isotopic compositions are recorded close to the source (δ(18)O between -14.1 and -13.8 ‰, δD between -100.3 and -97.0 ‰), and δD and δ(18)O values generally increase downstream through the upper part (UP, the mountainous sector), stabilizing along the lower part (LP, the alluvial plain) of the river with δ(18)O between -12.4 and -11.8 ‰, δD between -86.9 and -83.7 ‰. The isotopic variations along the stream path (δ(18)O-δD vs distance from the source) depict subparallel distributions for all the investigated periods, with less negative values recorded in winter. Total dissolved solids (TDS) concentration shows the lowest value (climatic changes. Monitoring is fundamental for future water management to overcome the vanishing of a significant water end-member of the basin, i.e., the glacio-nival reservoir that is severely affected by the ongoing climatic changes.

  12. Radiocarbon dating versus volcanic event stratigraphy: Age modelling of Quaternary marine sequences in the coastal region of the Eastern Tyrrhenian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Molisso, F., E-mail: flavia.molisso@iamc.cnr.i [Istituto per l' Ambiente Marino Costiero (IAMC) - CNR, Napoli, Calata P.ta di Massa, Porto di Napoli, 80133 Napoli (Italy); Insinga, D. [Istituto per l' Ambiente Marino Costiero (IAMC) - CNR, Napoli, Calata P.ta di Massa, Porto di Napoli, 80133 Napoli (Italy); Marzaioli, F. [Dipartimento di Scienze Ambientali, Seconda Universita di Napoli, Via Vivaldi, 43-81100 Caserta (Italy); CIRCE, INNOVA, Via Campi Flegrei 34, Pozzuoli 80078 (Italy); Sacchi, M. [Istituto per