Viser treff 688-698 av 698

    • Water column methanotrophy controlled by a rapid oceanographic switch 

      Steinle, Lea; Graves, Carolyn A.; Treude, Tina; Ferré, Benedicte; Biastoch, Arne; Bussmann, Ingeborg; Berndt, Christian; Krastel, Sebastian; James, Rachel H.; Behrens, Erik; Böning, Claus W.; Greinert, Jens; Sapart, Célia-Julia; Scheinert, Markus; Sommer, Stefan; Lehmann, Moritz F.; Niemann, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-04-20)
      Large amounts of the greenhouse gas methane are released from the seabed to the water column, where it may be consumed by aerobic methanotrophic bacteria. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column, are thought to be mainly controlled by nutrient and redox dynamics. Here, we report repeated measurements of methanotrophic ...
    • Water mass exchange between the Nordic Seas and the Arctic Ocean on millennial time scale during MIS 4–2 

      Rasmussen, Tine Lander; Thomsen, Erik; Nielsen, Tove (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      The climate of the last glaciation circa 65,000–25,000 years ago was interrupted by about 15 abrupt temperature fluctuations, the so-called Dansgaard-Oeschger events consisting of warm interstadials and cold stadials recorded in Greenland ice cores. The largest fluctuations occur in the North Atlantic region, but they have been registered over the most of the world. The events are linked to changes ...
    • Water redistribution in experimentally deformed natural milky quartz single crystals?Implications for H2O-weakening processes 

      Stünitz, H.; Thust, A.; Heilbronner, R.; Behrens, H.; Kilian, R.; Tarantola, A.; Fitz Gerald, J.D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-22)
      Natural quartz single crystals were experimentally deformed in two orientations: (1) ⊥ to one prism plane and (2) in O+ orientation at 900 and 1000°C, 1.0 and 1.5 GPa, and strain rates of ~1 × 10−6 s−1. In addition, hydrostatic and annealing experiments were performed. The starting material was milky quartz, which consisted of dry quartz with a large number of fluid inclusions of variable size up ...
    • Widespread and accelerating glacier retreat on the Lyngen Peninsula, northern Norway, since their 'Little Ice Age' maximum 

      Stokes, Chris R.; Andreassen, Liss Marie; Champion, Matthew R; Corner, Geoffrey D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-06)
      The recession of mountain glaciers worldwide is increasing global sea level and, in many regions, human activities will have to adapt to changes in surface hydrology. Thus, it is important to provide up-to-date analyses of glacier change and the factors modulating their response to climate warming. Here we report changes in the extent of >120 glaciers on the Lyngen Peninsula, northern Norway, where ...
    • Widespread natural methane and oil leakage from sub-marine Arctic reservoirs 

      Serov, Pavel; Mattingsdal, Rune; Winsborrow, Monica; Patton, Henry; Andreassen, Karin Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-30)
      Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this light, understanding the distribution and contribution of potential geological methane sources is important. Here we present empirical observations of hitherto undocumented, widespread and extensive methane ...
    • Widespread partial-depth hydrofractures in ice sheets driven by supraglacial streams 

      Chandler, David Matthew; Hubbard, Alun (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-19)
      Dramatic supraglacial lake drainage events in Greenland and Antarctica are enabled by rapid hydrofracture propagation through ice over 1 km thick. Here we present a slower mode of hydrofracture, where hairline surface fractures intersect supraglacial streams, and hypothesize that penetration depth is critically limited by water supply and englacial refreezing. We develop a model of stream-fed ...
    • Widespread subseafloor gas hydrate in the Barents Sea and Norwegian Margin 

      Cook, A.E.; Portnov, Alexey; Heber, R.C.; Vadakkepuliyambatta, Sunil; Bünz, Stefan (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)
      The distribution and concentration of subseafloor natural gas hydrate across margins is not well understood, because these systems are challenging to image and quantify remotely. Furthermore, it is unknown if shallow hydrate systems are linked to deeper oil and gas reservoirs. Herein, we analyze petroleum industry well logs with data in the gas hydrate stability zone and find that low concentrations ...
    • WNW-ESE-striking Timanian faults in Svalbard 

      Koehl, Jean-Baptiste P. (Conference object; Konferansebidrag, 2019-10)
    • Wood Jams Or Beaver Dams? Pliocene Life, Sediment And Landscape Interactions In The Canadian High Arctic 

      Davies, Neil S.; Gosse, John C; Rouillard, Alexandra; Rybczynski, Natalia; Meng, Jing; Reyes, Alberto V.; Kiguktak, Jarloo (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-28)
      During the mid-Pliocene (Zanclean, ca. ~ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–228C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative ...
    • You learn as long as you drill; research synthesis from the Longyearbyen CO2 Laboratory, Svalbard, Norway 

      Olaussen, Snorre; Senger, Kim; Braathen, Alvar; Grundvåg, Sten-Andreas; Mørk, Atle (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-21)
      From 2007 to 2015, eight wells were drilled and fully cored to test the feasibility of storing CO<sub>2</sub> emitted from the coal-fueled power plant in Longyearbyen, Svalbard. The drilling campaign identified three water-bearing sandstone aquifers; i) a lower aquifer in Upper Triassic strata; ii) a middle aquifer in Upper Triassic to Middle Jurassic; and iii) an upper aquifer in Lower Cretaceous ...
    • Younger Dryas ice margin retreat in Greenland: new evidence from southwestern Greenland 

      Funder, Svend; Sørensen, Anita H. L.; Larsen, Nicolaj K.; Bjørk, Anders A.; Briner, Jason P.; Olsen, Jesper; Schomacker, Anders; Levy, Laura B.; Kjær, Kurt H. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-04)
      To date the final stage in deglaciation of the Greenland shelf, when a contiguous ice sheet margin on the inner shelf transitioned to outlet glaciers in troughs with intervening ice-free areas, we generated cosmogenic <sup>10</sup>Be dates from bedrock knobs on six outlying islands along a stretch of 300 km of the southwestern Greenland coast. Despite <sup>10</sup>Be inheritance influencing some ...