• 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 ...
    • 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)
    • 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)
    • Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling 

      Pisso, Ignacio; Myhre, Cathrine Lund; Platt, Stephen Matthew; Eckhardt, Sabine; Hermansen, Ove; Schmidbauer, Josef Norbert; Mienert, Jurgen; Vadakkepuliyambatta, Sunil; Bauguitte, S.; Pitt, J; Allen, G.; Bower, KN; O'Shea, S; Gallagher, MW; Percival, C.J; Pyle, J; Cain, M.; Stohl, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-10)
    • The EMSO-ERIC pan-european consortium: Data benefits and lessons learned as the legal entity forms 

      Best, Mairi M.R.; Favali, Paolo; Beranzoli, Laura; Blandin, Jerome; Çağatay, Namik M.; Cannat, Mathilde; Dañobeitia, Juan José; Delory, Eric; de Miranda, Jorge M.A.; Del Rio Fernandez, Joaquin; de Stigter, Henko; Gillooly, Mick; Grant, Fiona; Hall, Per O.J.; Hartman, Susan E.; Hernandez-Brito, Joaquin; Lanteri, Nadine; Mienert, Jurgen; Oaie, Gheorge; Piera, Jaume; Radulescu, Vlad; Rolin, Jean-Francois; Ruhl, Henry A.; Waldmann, Christoph (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-01)
      The European Multidisciplinary Seafloor and water-column Observatory (EMSO) European Research Infrastructure Consortium (ERIC) provides power, communications, sensors, and data infrastructure for continuous, high-resolution, (near-)real-time, interactive ocean observations across a multidisciplinary and interdisciplinary range of research areas including biology, geology, chemistry, physics, ...
    • Extensive release of methane from Arctic seabed west of Svalbard during summer 2014 does not influence the atmosphere 

      Myhre, Cathrine Lund; Ferré, Benedicte; Platt, Stephen Matthew; Silyakova, Anna; Hermansen, Ove; Allen, Grant; Pisso, Ignacio; Schmidbauer, Josef Norbert; Stohl, Andreas; Pitt, Joseph R.; Jansson, Pær; Greinert, Jens; Percival, Carl; Fjæraa, Ann Mari; O'Shea, Sebastian J.; Gallagher, Martin; Le Breton, Michael; Bower, Keith N.; Bauguitte, Stéphane Jean-Bernard; Dalsøren, Stig Bjørløw; Vadakkepuliyambatta, Sunil; Fisher, Rebecca E.; Nisbet, Euan G.; Lowry, David; Myhre, Gunnar; Pyle, John Adrian; Cain, Michelle; Mienert, Jurgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-07)
      We find that summer methane (CH4) release from seabed sediments west of Svalbard substantially increases CH4 concentrations in the ocean but has limited influence on the atmospheric CH4 levels. Our conclusion stems from complementary measurements at the seafloor, in the ocean, and in the atmosphere from land-based, ship and aircraft platforms during a summer campaign in 2014. We detected high ...
    • Geological controls on fluid flow and gas hydrate pingo development on the Barents Sea margin 

      Waage, Malin; Portnov, Aleksei D; Serov, Pavel; Bünz, Stefan; Waghorn, Kate Alyse; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Andreassen, Karin (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-16)
      In 2014, the discovery of seafloor mounds leaking methane gas into the water column in the northwestern Barents Sea became the first to document the existence of non‐permafrost related gas hydrate pingos (GHP) on the Eurasian Arctic shelf. The discovered site is given attention because the gas hydrates occur close to the upper limit of the gas hydrate stability, thus may be vulnerable to climatic ...
    • High-resolution 3D seismic exhibits new insights into the middle-late Pleistocene stratigraphic evolution and sedimentary processes of the Bear Island trough mouth fan 

      Waage, Malin; Bünz, Stefan; Bøe, Reidulv; Mienert, Jurgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-21)
      Arctic Ocean trough mouth fans (TMFs) represent a valuable archive of glacial-interglacial sedimentary processes that are especially important when reconstructing pre-Weichselian glaciations that may lack distinct imprints on the shelves. In 2011, we acquired the first high-resolution 3D seismic cube (~3 m vertical and 6 m horizontal resolution) on the continental slope of the SW Barents Sea by use ...
    • High-resolution underwater laser spectrometer sensing provides new insights into methane distribution at an Arctic seepage site 

      Jansson, Pär; Triest, Jack; Grilli, Roberto; Ferré, Benedicte; Silyakova, Anna; Mienert, Jurgen; Chappellaz, Jérôme (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-13)
      Methane (CH4) in marine sediments has the potential to contribute to changes in the ocean and climate system. Physical and biochemical processes that are difficult to quantify with current standard methods such as acoustic surveys and discrete sampling govern the distribution of dissolved CH4 in oceans and lakes. Detailed observations of aquatic CH4 concentrations are required for a better understanding ...
    • Ice-sheet-driven methane storage and release in the Arctic 

      Portnov, Aleksei D; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-07)
      It is established that late-twentieth and twenty-first century ocean warming has forced dissociation of gas hydrates with concomitant seabed methane release. However, recent dating of methane expulsion sites suggests that gas release has been ongoing over many millennia. Here we synthesize observations of B1,900 fluid escape features—pockmarks and active gas flares—across a previously glaciated ...
    • Methane at Svalbard and over the European Arctic Ocean 

      Platt, Stephen Matthew; Eckhardt, Sabine; Ferré, Benedicte; Fisher, Rebecca E.; Hermansen, Ove; Jansson, Pär; Lowry, David; Nisbet, Euan G.; Pisso, Ignacio; Schmidbauer, Norbert; Silyakova, Anna; Stohl, Andreas; Svendby, Tove Marit; Vadakkepuliyambatta, Sunil; Mienert, Jurgen; Myhre, Cathrine Lund (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-12-05)
      Methane (CH<sub>4</sub>) is a powerful greenhouse gas. Its atmospheric mixing ratios have been increasing since 2005. Therefore, quantification of CH<sub>4</sub> sources is essential for effective climate change mitigation. Here we report observations of the CH<sub>4</sub> mixing ratios measured at the Zeppelin Observatory (Svalbard) in the Arctic and aboard the research vessel (RV) Helmer Hanssen ...
    • Methane release from pingo-like features across the South Kara Sea shelf, an area of thawing offshore permafrost 

      Serov, Pavel; Portnov, Aleksei D; Mienert, Jurgen; Semenov, Peter; Ilatovskaya, Polonia (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-16)
      The Holocene marine transgression starting at ~19 ka flooded the Arctic shelves driving extensive thawing of terrestrial permafrost. It thereby promoted methanogenesis within sediments, the dissociation of gas hydrates, and the release of formerly trapped gas, with the accumulation in pressure of released methane eventually triggering blowouts through weakened zones in the overlying and thinned ...
    • Microseismicity linked to gas migration and leakage on the western Svalbard shelf 

      Franek, Peter; Plaza-Faverola, Andreia; Mienert, Jurgen; Bünz, Stefan; Ferré, Benedicte; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-26)
      The continental margin off Prins Karls Forland, western Svalbard, is characterized by widespread natural gas seepage into the water column at and upslope of the gas hydrate stability zone. We deployed an ocean bottom seismometer integrated into the MASOX (Monitoring Arctic Seafloor-Ocean Exchange) automated seabed observatory at the pinch-out of this zone at 389 m water depth to investigate passive ...
    • Modeling the evolution of climate-sensitive Arctic subsea permafrost in regions of extensive gas expulsion at the West Yamal shelf 

      Portnov, Aleksei D; Mienert, Jurgen; Serov, Pavel (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-01)
      Thawing subsea permafrost controls methane release from the Russian Arctic shelf having a considerable impact on the climate-sensitive Arctic environment. Expulsions of methane from shallow Russian Arctic shelf areas may continue to rise in response to intense degradation of relict subsea permafrost. Here we show modeling of the permafrost evolution from the Late Pleistocene to present time at the ...
    • Modelling persistent methane seepage offshore western Svalbard since early Pleistocene 

      Knies, Jochen; Daszinnies, Matthias Christian; Plaza-Faverola, Andreia; Chand, Shyam; Sylta, Øyvind; Bünz, Stefan; Johnson, Joel E; Mattingsdal, Rune; Mienert, Jurgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-31)
      Recent observations of extensive methane release into the oceans and atmosphere have raised concern as to whether rising temperatures across the Arctic could drive rapid destabilization of gas hydrate reservoirs. Here, we report modelling results from hydrate-modulated methane seepage from Vestnesa Ridge, offshore western Svalbard, suggesting that continuous leakage has occurred from the seafloor ...
    • A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders: Examples from the Arctic offshore NW-Svalbard 

      Veloso, M.; Greinert, Jens; Mienert, Jurgen; De Batist, M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-08)
      Quantifying marine methane fluxes of free gas (bubbles) from the seafloor into the water column is of importance for climate related studies, for example, in the Arctic, reliable methodologies are also of interest for studying man-made gas and oil leakage systems at hydrocarbon production sites. Hydroacoustic surveys with singlebeam and nowadays also multibeam systems have been proven to be a ...
    • Norwegian margin outer shelf cracking: a consequence of climate-induced gas hydrate dissociation? 

      Vanneste, Maarten; Mienert, Jurgen; Haflidason, H; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
    • Ocean temperature variability for the past 60 years on the Norwegian-Svalbard margin influences gas hydrate stability on human time scales 

      Ferré, Benedicte; Mienert, Jurgen; Feseker, Tomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-10-23)
      The potential impact of future climate change on methane release from oceanic gas hydrates is the subject of much debate. We analyzed World Ocean Database quality controlled data on the Norwegian‐Svalbard continental margin from the past 60 years to evaluate the potential effect of ocean temperature variations on continental margin gas hydrate reservoirs. Bottom water temperatures in the Norwegian‐Svalbard ...
    • Offshore permafrost decay and massive seabed methane escape in water depths >20 m at the South Kara Sea shelf 

      Portnov, Alexey; Mienert, Jurgen; Cherkashov, Georgy; Rekant, Pavel; Semenov, Peter; Serov, Pavel; Vanshtein, Boris; Smith, Andrew James (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-07-14)
      Since the Last Glacial Maximum (~19 ka), coastal inundation from sea-level rise has been thawing thick subsea permafrost across the Arctic. Although subsea permafrost has been mapped on several Arctic continental shelves, permafrost distribution in the South Kara Sea and the extent to which it is acting as an impermeable seal to seabed methane escape remains poorly understood. Here we use >1300 km ...
    • Particle sources and downward fluxes in the eastern Fram strait under the influence of the west Spitsbergen current 

      Sanchez-Vidal, Anna; Veres, Oriol; Langone, Leonardo; Ferré, Benedicte; Calafat, Antoni; Canals, Miquel; Durrieu de Madron, Xavier; Heussner, Serge; Mienert, Jurgen; Grimalt, Joan O.; Pusceddu, Antonio; Danovaro, Roberto (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-10)
      <p>The carbon cycle of the Arctic Ocean is tightly regulated by land–atmosphere–cryosphere–ocean interactions. Characterizing these environmental exchanges and feedbacks is critical to facilitate projections of the carbon cycle under changing climate conditions. The environmental drivers of sinking particles including organic carbon (OC) to the deep-sea floor are investigated with four moorings ...