Now showing items 141-160 of 1011

    • Pelagic calcium carbonate production and shallow dissolution in the North Pacific Ocean 

      Ziveri, Patrizia; Gray, William Robert; Anglada Ortiz, Griselda; Manno, Clara; Grelaud, Michael; Incarbona, Alessandro; Rae, James William Buchanan; Subhas, Adam V.; Pallacks, Sven; White, Angelicque; Adkins, Jess F.; Berelson, William (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-20)
      Planktonic calcifying organisms play a key role in regulating ocean carbonate chemistry and atmospheric CO<sub>2</sub>. Surprisingly, references to the absolute and relative contribution of these organisms to calcium carbonate production are lacking. Here we report quantification of pelagic calcium carbonate production in the North Pacific, providing new insights on the contribution of the three ...
    • Sedimentology of Neoproterozoic storm-influenced braid deltas, Varanger Peninsula, North Norway 

      Grundvåg, Sten-Andreas; Skorgenes, Julia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-30)
      The oldest part of the upper Riphean (Cryogenian) sedimentary succession of the Varanger Peninsula, North Norway, includes a series of sandstone-dominated units of fluvio-deltaic to shallow-marine origin and thinner, intercalated mudstone-rich units. The sedimentology and stratigraphic understanding of the mudstone-rich units are less complete compared to their sandstone-dominated counterparts. In ...
    • Quaternary and Neogene Reservoirs of the Norwegian Continental Shelf and the Faroe-Shetland Basin 

      Bellwald, Benjamin; Planke, Sverre; Vadakkepuliyambatta, Sunil; Buenz, Stefan; Batchelor, Christine L.; Manton, Ben; Zastrozhnov, Dmitry; Walker, Faye; Myklebust, Reidun (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-01)
      Glaciogenic reservoirs host important hydrocarbon resources across the globe. Examples such as the Peon and Aviat discoveries in the North Sea show that Quaternary and Neogene reservoirs can be prospective in the region. In this study, we interpret 2D and 3D reflection seismic data combined with borehole information to document unconventional play models from the shallow subsurface of the Norwegian ...
    • The Svalbard Carboniferous to Cenozoic Composite Tectono-Stratigraphic Element 

      Olaussen, Snorre; Grundvåg, Sten-Andreas; Senger, Kim; Anell, Ingrid; Betlem, Peter; Birchall, Thomas; Braathen, Alvar; Dallmann, Winfried Kurt; Jochmann, Malte Michel; Johannessen, Erik P.; Lord, Gareth Steven; Mørk, Atle; Osmundsen, Per Terje; Smyrak-Sikora, Aleksandra; Stemmerik, Lars (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-26)
      The Svalbard Composite Tectono-Stratigraphic Element is located on the north-western corner of the Barents Shelf and comprises a Carboniferous to Pleistocene sedimentary succession. Due to Cenozoic uplift the succession is subaerially exposed in the Svalbard archipelago. The oldest parts of the succession consist of Carboniferous to Permian mixed siliciclastic, carbonate and evaporite and spiculitic ...
    • Climate and sea-ice development between 890 and 1660 CE in SW Greenland revealed by marine diatom studies 

      Enguídanos, Eira Triguero (Master thesis; Mastergradsoppgave, 2022-11-24)
      This thesis presents the results of august Sea Surface Temperature reconstructions from marine diatom assemblages in samples from core Ga3-2 retrieved from Narsaq Sound, inside the Ikersuad fjord, South Greenland. The diatom samples provide a high-resolution (~30-year) reconstruction dating between 890 and 1660 CE (common era). The results show variable conditions with warm periods between 960 and ...
    • Introduction: Processes and Palaeo-Environmental Changes in the Arctic from Past to Present (PalaeoArc) special issue 

      Lyså, Astrid; Jennings, Anne; Morigi, Caterina; Stokes, Chris R.; Winsborrow, Monica (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-05)
      PalaeoArc (Processes and Palaeo-Environmental Changes in the Arctic: From Past to Present) is an international network research programme, the aim of which is to understand and explain the climatically induced environmental changes in the Arctic that have taken place throughout the Quaternary and continue in the present-day (see http://www.palaeoarc.no/). This network builds on and extends the ...
    • Plastic photodegradation under simulated marine conditions 

      Delre, Annalisa; Goudriaan, Maaike; Morales, Victor Hernando; Vaksmaa, Annika; Rachel Tintswalo, Ndhlovu; Marianne, Baas; Keijzer, Edwin; de Groot, Tim; Zeghal, Emna; Egger, Matthias; Röckmann, Thomas; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-12)
      Ocean plastic pollution is a problem of increasing magnitude; yet, the amount of plastic at the sea surface is much lower than expected. Solar ultraviolet (UV) radiation can induce photodegradation, but its importance in determining the longevity of floating plastic remains unconstrained. Here, we measured photodegradation rates of different plastic types slightly larger than microplastics (virgin ...
    • Using thermal UAV imagery to model distributed debris thicknesses and sub-debris melt rates on debris-covered glaciers 

      Bisset, Rosie R.; Nienow, Peter W.; Goldberg, Daniel N.; Wigmore, Oliver; Loayza-Muro, Raúl A.; Wadham, Jemma Louise; Macdonald, Moya L.; Bingham, Robert G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-14)
      Supraglacial debris cover regulates the melt rates of many glaciers in mountainous regions around the world, thereby modifying the availability and quality of downstream water resources. However, the influence of supraglacial debris is often poorly represented within glaciological models, due to the absence of a technique to provide high-precision, spatially continuous measurements of debris thickness. ...
    • Glacial history and depositional environments in little Storfjorden and Hambergbukta of Arctic Svalbard since the younger dryas 

      Joe, Young Jin; Jang, Kwangchul; Forwick, Matthias; Laberg, Jan Sverre; Kong, Gee Soo; Kang, Moo-Hee; Yoon, Seok-Hoon; Nam, Seung-Il (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-21)
      Geophysical and lithological data provide crucial information for the understanding of glacial history in Arctic Svalbard. In this study, we reconstructed the glacier-induced depositional environments of Little Storfjorden and its tributary, Hambergbukta, over the last 13 ka to better understand the glacial history of southeastern Svalbard. The combined uses of swath-bathymetry, high-resolution ...
    • Factors controlling the net ecosystem production of cryoconite on Western Himalayan glaciers 

      Shamurailatpam, Monica S.; Telling, Jon; Wadham, Jemma Louise; Ramanathan, A. L.; Yates, Christopher A.; Raju, N. Janardhana (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-07)
      In situ experiments were conducted to determine the net ecosystem production (NEP) in cryoconite holes from the surface of two glaciers (Patsio glacier and Chhota Shigri glacier) in the Western Himalaya during the melt season from August to September 2019. The study aimed to gain an insight into the factors controlling microbial activity on glacier surfaces in this region. A wide range of parameters, ...
    • Contrasting Neogene–Quaternary continental margin evolution offshore mid-north Norway: Implications for source-to-sink systems 

      Olsen, Stine-Bjordal; Rydningen, Tom Arne; Laberg, Jan Sverre; Lasabuda, Amando P. E.; Knutsen, Stig Morten (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-22)
      The Neogene–Quaternary development of the ∼700 km long mid-Norwegian and Lofoten–Vesterålen continental margin is reconstructed using a dense grid of 2D seismic data and exploration wellbores. Overall, widespread ocean current-controlled contourite drifts built up along the whole margin segment from the mid-Miocene onwards (c. 11 Ma, Kai Formation). The onset (c. 8.8 Ma) of a large inner shelf ...
    • Structural and metamorphic history of the Leech river shear zone, Vancouver Island, British Columbia 

      Seyler, Caroline E.; Kirkpatrick, James D.; Faber, Carly; Licht, Alexis; Šilerová, Dina; Regalla, Christine (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-13)
      The Leech River Shear Zone (LRSZ) on southern Vancouver Island separates the metasedimentary schists of the Leech River Complex (LRC) from the accreted oceanic plateau of the Siletz-Crescent terrane. The juxtaposition of these rock units suggests a possible origin as a subduction plate boundary but tectonic context of the LRSZ has yet to be fully established. We present field, microstructural, ...
    • Active Nordic Seas deep-water formation during the last glacial maximum 

      Larkin, Christina S.; Mohamed, Mohamed Mahmoud Ezat Ahmed; Roberts, Natalie L.; Bauch, Henning A.; Spielhagen, Robert F.; Noormets, Riko; Polyak, Leonid; Moreton, Steven G.; Rasmussen, Tine Lander; Sarnthein, Michael; Tipper, Edward T.; Piotrowski, Alex M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-24)
      The Nordic Seas are the primary location where the warm waters of the North Atlantic Current densify to form North Atlantic Deep Water, which plays a key part in the modern Atlantic Meridional Overturning Circulation. The formation of dense water in the Nordic Seas and Arctic Ocean and resulting ocean circulation changes were probably driven by and contributed to the regional and global climate of ...
    • A stable isotope assay with 13C-labeled polyethylene to investigate plastic mineralization mediated by Rhodococcus ruber 

      Goudriaan, Maaike; Morales, Victor Hernando; van der Meer, Marcel T.J.; Mets, Anchelique; Ndhlovu, Rachel T.; van Heerwaarden, Johan; Simon, Sina; Heuer, Verena B.; Hinrichs, Kai-Uwe; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-30)
      Methods that unambiguously prove microbial plastic degradation and allow for quantification of degradation rates are necessary to constrain the influence of microbial degradation on the marine plastic budget. We developed an assay based on stable isotope tracer techniques to determine microbial plastic mineralization rates in liquid medium on a lab scale. For the experiments, <sup>13</sup>C-labeled ...
    • Methane release from open leads and new ice following an Arctic winter storm event 

      Silyakova, Anna; Nomura, Daiki; Kotovitch, Marie; Fransson, Agneta; Delille, Bruno; Chierici, Melissa; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-03)
      We examine an Arctic winter storm event, which led to ice break–up, the formation of open leads, and the subsequent freezing of these leads. The methane (CH<sub>4</sub>) concentration in under–ice surface water before and during the storm event was 8–12 nmol L<sup>−1</sup>, which resulted in a potential sea–to–air CH<sub>4</sub> flux ranging from +0.2 to +2.1 mg CH<sub>4</sub> m<sup>−2</sup> ...
    • Catchment characteristics and seasonality control the composition of microbial assemblages exported from three outlet glaciers of the Greenland Ice Sheet 

      Vrbická, Kristýna; Kohler, Tyler J.; Falteisek, Lukáš; Hawkings, Jon R.; Vinšová, Petra; Bulínová, Marie; Lamarche-Gagnon, Guillaume; Hofer, Stefan; Kellerman, Anne M.; Holt, Amy D.; Cameron, Karen Anne; Schön, Martina; Wadham, Jemma Louise; Stibal, Marek (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-29)
      Glacial meltwater drains into proglacial rivers where it interacts with the surrounding landscape, collecting microbial cells as it travels downstream. Characterizing the composition of the resulting microbial assemblages in transport can inform us about intra-annual changes in meltwater flowpaths beneath the glacier as well as hydrological connectivity with proglacial areas. Here, we investigated ...
    • Digitising Svalbard’s geology: the Festningen digital outcrop model 

      Senger, Kim; Betlem, Peter; Birchall, Thomas; Gonzaga Jr., Luis; Grundvåg, Sten-Andreas; Horota, Rafael Kenji; Laake, Andreas; Kuckero, Lilith; Mørk, Atle; Planke, Sverre; Rodes, Nil; Smyrak-Sikora, Aleksandra (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-10)
      The renowned Festningen section in the outer part of Isfjorden, western Spitsbergen, offers a c. 7 km-long nearly continuous stratigraphic section of Lower Carboniferous to Cenozoic strata, spanning nearly 300 million years of geological history. Tectonic deformation associated with the Paleogene West-Spitsbergen-Fold-and-Thrust belt tilted the strata to near-vertical, allowing easy access to the ...
    • An annual profile of the impacts of simulated oil spills on the Northeast Arctic cod and haddock fisherie 

      Carroll, JoLynn; Frøysa, Håvard Guldbrandsen; Vikebø, Frode Bendiksen; Broch, Ole Jacob; Nepstad, Raymond; Augustine, Starrlight; Skeie, Geir Morten; Bockwoldt, Mathias; Howell, Daniel (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-10)
      We simulate the combined natural and pollutant-induced survival of early life stages of NEA cod and haddock, and the impact on the adult populations in response to the time of a major oil spill in a single year. Our simulations reveal how dynamic ocean processes, controlling both oil transport and fate and the frequency of interactions of oil with drifting fish eggs and larvae, mediate the magnitude ...
    • Hot Vents Beneath an Icy Ocean: The Aurora Vent Field, Gakkel Ridge, Revealed 

      Ramirez-Llodra, Eva; Argentino, Claudio; Baker, Maria; Boetius, Antje; Costa, Carolina; Dahle, Håkon; Denny, Emily Maria; Dessandier, Pierre-Antoine; Eilertsen, Mari Heggernes; Ferré, Benedicte; German, Cristopher R.; Hand, Kevin; Hilário, Ana; Hislop, Lawrence; Jamieson, John W.; Kalnitchenko, Dimitri; Mall, Achim; Panieri, Giuliana; Purser, Autun; Ramalho, Sofia P.; Reeves, Eoghan P.; Rolley, Leigthon; Pereira, Samuel I.; Ribeiro, Pedro A.; Sert, Muhammed Fatih; Steen, Ida H.; Stetzler, Marie; Stokke, Runar; Victorero, Lissette; Vulcano, Francesca; Vågenes, Stig; Waghorn, Kate Alyse; Buenz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-28)
      Evidence of hydrothermal venting on the ultra-slow spreading Gakkel Ridge in the Central Arctic Ocean has been available since 2001, with first visual evidence of black smokers on the Aurora Vent Field obtained in 2014. But it was not until 2021 that the first ever remotely operated vehicle (ROV) dives to hydrothermal vents under permanent ice cover in the Arctic were conducted, enabling the ...
    • The extreme yet transient nature of glacial erosion 

      Patton, Henry; Hubbard, Alun; Heyman, J.; Alexandropoulou, Nikolitsa; Lasabuda, Amando P. E.; Stroeven, A.P.; Hall, A.M.; Winsborrow, Monica; Sugden, David E.; Kleman, J.; Andreassen, Karin Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-30)
      Ice can sculpt extraordinary landscapes, yet the efficacy of, and controls governing, glacial erosion on geological timescales remain poorly understood and contended, particularly across Polar continental shields. Here, we assimilate geophysical data with modelling of the Eurasian Ice Sheet — the third largest Quaternary ice mass that spanned 49°N to 82°N — to decipher its erosional footprint during ...