Now showing items 1-20 of 215

    • 3D Seismic Investigation of a Gas Hydrate and Fluid Flow System on an Active Mid‐Ocean Ridge; Svyatogor Ridge, Fram Strait 

      Waghorn, Kate Alyse; Bünz, Stefan; Plaza-Faverola, Andreia; Johnson, Joel E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-12)
      Tectonic settings play a large role in the development of fluid flow pathways for gas migrating through sedimentary strata. Many gas hydrate systems worldwide are located on either passive continental margins, in large contourite deposits on the slopes of passive continental margins or on subduction margins. The Svyatogor Ridge, however, located at the northwestern flank of the Knipovich Ridge and ...
    • Abiotic methane from ultraslow-spreading ridges can charge Arctic gas hydrates 

      Johnson, Joel E; Mienert, Jurgen; Plaza-Faverola, Andreia; Vadakkepuliyambatta, Sunil; Knies, Jochen; Bünz, Stefan; Andreassen, Karin; Ferré, Benedicte (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05)
      Biotic gas generation from the degradation of organic carbon in marine sediments supplies and maintains gas hydrates throughout the world’s oceans. In nascent, ultraslow-spreading ocean basins, methane generation can also be abiotic, occurring during the high-temperature (>200 °C) serpentinization of ultramafic rocks. Here, we report on the evolution of a growing Arctic gas- and gas hydrate–charged ...
    • Acoustic generation of underwater cavities - Comparing modeled and measured acoustic signals generated by seismic air gun arrays 

      Khodabandeloo, Babak; Landrø, Martin; Hanssen, Alfred (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-14)
      Underwater vapor cavities can be generated by acoustic stimulation. When the acoustic signals from several air guns are reflected from the sea surface, the pressure drop at some locations is sufficient for cavity growth and subsequent collapse. In this paper the generation of multiple water vapor cavities and their collapses are numerically modeled and the results are validated by comparing with ...
    • Arctic megaslide at presumed rest 

      Geissler, Wolfram H.; Gebhardt, Catalina; Gross, Felix; Wollenburg, Jutta; Jensen, Laura; Schmidt-Aursch, Mechita; Krastel, Sebastian; Elger, Judith; Osti, Giacomo (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope ...
    • Assessing impacts of simulated oil spills on the Northeast Arctic cod fishery 

      Carroll, JoLynn; Vikebø, Frode Bendiksen; Howell, Daniel; Broch, OJ; Nepstad, Raymond; Augustine, Starrlight; Skeie, Geir Morten; Bast, Radovan; Juselius, Jonas (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-04)
      We simulate oil spills of 1500 and 4500 m3/day lasting 14, 45, and 90 days in the spawning grounds of the commercial fish species, Northeast Arctic cod. Modeling the life history of individual fish eggs and larvae, we predict deviations from the historical pattern of recruitment to the adult population due to toxic oil exposures. Reductions in survival for pelagic stages of cod were 0–10%, up to a ...
    • Assessment of offshore wind power potential in the Aegean and Ionian<br> Seas based on high-resolution hindcast model results 

      Soukissian, Takvor; Papadopoulos, Anastasios; Skrimizeas, Panagiotis; Karathanasi, Flora; Axaopoulos, Panagiotis; Avgoustoglou, Evripides; Kyriakidou, Hara; Tsalis, Christos; Voudouri, Antigoni; Gofa, Flora; Katsafados, Petros (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-20)
      In this study long-term wind data obtained from high-resolution hindcast simulations is used to analytically assess offshore wind power potential in the Aegean and Ionian Seas and provide wind climate and wind power potential characteristics at selected locations, where offshore wind farms are at the concept/planning phase. After ensuring the good model performance through detailed validation against ...
    • Asynchronous response of marine-terminating outlet glaciers during deglaciation of the Fennoscandian Ice Sheet 

      Stokes, Chris R.; Corner, Geoffrey D.; Winsborrow, Monica; Husum, Katrine; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-03-31)
      Recent studies have highlighted the dynamic behavior of marine-terminating outlet glaciers over decadal time scales, linked to both atmospheric and oceanic warming. This helps explain episodes of nearly synchronous fl ow acceleration, thinning, and retreat, but nonclimatic factors such as changes in fjord width and depth, can also induce rapid recession. There is support for these topographic ...
    • BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass conservation 

      Morlighem, Mathieu; Williams, Chris N.; Rignot, Eric J.M.; An, Lu; Arndt, Jan Erik; Bamber, Jonathan L.; Catania, Ginny A.; Chauché, Nolwenn; Dowdeswell, Julian A.; Dorschel, Boris; Fenty, Ian; Hogan, Kelly A.; Howat, Ian M.; Hubbard, Alun Lloyd; Jakobsson, Martin; Jordan, Thomas M.; Kjeldsen, Kristian Kjellerup; Millan, Romain; Mayer, Larry; Mouginot, Jérémie; Noël, Brice P.Y.; O'Cofaigh, Colm; Palmer, Steven; Rysgaard, Søren; Seroussi, Hélène; Siegert, Martin J.; Slabon, Patricia; Straneo, Fiamma; van den Broeke, Michiel R.; Weinrebe, Wilhelm Reimer; Wood, Michael; Zinglersen, Karl Brix (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-18)
      Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine‐terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness ...
    • Benthic foraminifera as bio-indicators of chemical and physical stressors in Hammerfest harbor (Northern Norway) 

      Dijkstra, Noortje; Junttila, Juho; Skirbekk, Kari; Carroll, JoLynn; Husum, Katrine; Hald, Morten (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-01)
      We investigated benthic foraminiferal assemblages in contaminated sediments in a subarctic harbor of northern Norway to assess their utility as indicators of anthropogenic impacts. Sediments in the harbor are repositories for POPs and heavy metals supplied through discharges from industry and shipping activities. Sediment contaminant concentrations are at moderate to poor ecological quality ...
    • Benthic foraminiferal growth seasons implied from Mg/Ca-temperature correlations for three Arctic species 

      Skirbekk, Kari; Hald, Morten; Thomas Jr., Marchitto; Junttila, Juho; Klitgaard Kristensen, Dorthe; Sørensen, Steffen Aagaard (Peer reviewed, 2016-11-22)
      Core-top sediment samples from Kongsfjorden, Svalbard, and adjacent fjord and shelf areas were collected in order to investigate a potential relationship between Mg/Ca-ratios of Arctic benthic foraminifera and the ambient bottom water temperatures (BWT). The area is influenced by large seasonal variation in factors such as light and temperature, which is further strengthened by oceanographic shifts, ...
    • Biocryomorphology: integrating microbial processes with ice surface hydrology, topography and roughness 

      Cook, J.; Edwards, A.; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-02)
    • Bivalve shell horizons in seafloor pockmarks of the last glacial-interglacial transition suggest a thousand years of methane emissions in the Arctic Ocean 

      Ambrose, William; Panieri, Giuliana; Schneider, Andrea; Plaza-Faverola, Andreia; Carroll, Michael Leslie; Åström, Emmelie; Locke, W.L.; Carroll, JoLynn (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-05)
      We studied discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (1200 m water depth) and western Svalbard (798000 N, 068550 W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20–30 cm thick and centered at ...
    • Bottom water acidification and warming on the western Eurasian Arctic shelves: Dynamical downscaling projections 

      Wallhead, P. J.; Bellerby, R.G.J.; Silyakova, A.; Slagstad, D.; Polukhin, A. A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-25)
      The impacts of oceanic CO2 uptake and global warming on the surface ocean environment have received substantial attention, but few studies have focused on shelf bottom water, despite its importance as habitat for benthic organisms and demersal fisheries such as cod. We used a downscaling ocean biogeochemical model to project bottom water acidification and warming on the western Eurasian Arctic ...
    • Bottom-simulating reflector dynamics at Arctic thermogenic gas provinces: An example from Vestnesa Ridge, offshore west Svalbard 

      Plaza-Faverola, Andreia; Vadakkepuliyambatta, Sunil; Hong, Wei-Li; Mienert, Jurgen; Bünz, Stefan; Chand, Shyam; Greinert, Jens (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06)
    • Brine formation in relation to climate changes and ice retreat during the last 15,000 years in Storfjorden, Svalbard, 76–78°N 

      Rasmussen, Tine Lander; Thomsen, Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-06)
      Storfjorden, Svalbard, is an area of intense brine formation. The brine is cold, dense, rich in oxygen and CO2, and has reduced pH. Storfjorden is unique because it contains well-preserved agglutinated foraminifera dating back to the beginning of the last deglaciation. We have investigated the distribution of calcareous and agglutinated benthic foraminifera, benthic oxygen and carbon isotopes, ...
    • The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing 

      Patton, Henry; Hubbard, Alun Lloyd; Andreassen, Karin; Winsborrow, Monica; Stroeven, Arjen P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-01)
      The Eurasian ice-sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum (LGM), after the Antarctic and North American ice sheets. Despite its global significance, a comprehensive account of its evolution from independent nucleation centres to its maximum extent is conspicuously lacking. Here, a first-order, thermomechanical model, robustly constrained by empirical evidence, ...
    • Carbon isotope (d13C) excursions suggest times of major methane release during the last 14 ka in Fram Strait, the deep-water gateway to the Arctic 

      Consolaro, Chiara; Rasmussen, Tine Lander; Panieri, Giuliana; Mienert, Jurgen; Bünz, Stefan; Sztybor, Kamila (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • Cascading lake drainage on the Greenland Ice Sheet triggered by tensile shock and fracture 

      Christoffersen, Poul; Bougamont, Marion; Hubbard, Alun; Doyle, Samuel H.; Grigsby, Shane; Pettersson, Rickard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-14)
      Supraglacial lakes on the Greenland Ice Sheet are expanding inland, but the impact on ice flow is equivocal because interior surface conditions may preclude the transfer of surface water to the bed. Here we use a well-constrained 3D model to demonstrate that supraglacial lakes in Greenland drain when tensile-stress perturbations propagate fractures in areas where fractures are normally absent or ...
    • The Cenozoic pre-glacial tectono-stratigraphy and erosion estimates for the NW Barents Sea 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Safronova, Polina (Conference object; Konferansebidrag, 2017-04-24)
    • Cenozoic tectonostratigraphy and pre-glacial erosion: A mass-balance study of the northwestern Barents Sea margin 

      Lasabuda, Amando Putra Ersaid; Laberg, Jan Sverre; Knutsen, Stig-Morten; Safronova, Polina (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-26)
      <p>The evolution of the northwestern Barents Sea continental margin, part of a NW-SE trending mega shear zone, has been reconstructed in order to quantify the sedimentation and erosion affecting this area during and after its formation in the Paleogene–Neogene. This development was closely related to the sea-floor opening of the Norwegian-Greenland Sea. Our study incorporated 2D seismic data, well ...