Now showing items 1-13 of 13

    • Asynchronous Accumulation of Organic Carbon and Nitrogen in the Atlantic Gateway to the Arctic Ocean 

      Paulsen, Maria Lund; Seuthe, Lena; Reigstad, Marit; Larsen, Aud; Cape, Matthias; Vernet, Maria (Frontiers, 2018-11-15)
      Nitrogen (N) is the main limiting nutrient for biological production in the Arctic Ocean. While dissolved inorganic N (DIN) is well studied, the substantial pool of N bound in organic matter (OM) and its bioavailability ...
      Journal article
    • Bacterial community composition responds to changes in copepod abundance and alters ecosystem function in an Arctic mesocosm study 

      Tsagaraki, Tatiana Margo; Pree, Bernadette; Leiknes, Øystein; Larsen, Aud; Bratbak, Gunnar; Øvreås, Lise; Egge, Jorun Karin; Spanek, Roman; Paulsen, Maria Lund; Olsen, Yngvar; Vadstein, Olav; Thingstad, T. Frede (Springer Nature, 2018)
      Combining a minimum food web model with Arctic microbial community dynamics, we have suggested that top-down control by copepods can affect the food web down to bacterial consumption of organic carbon. Pursuing this ...
      Journal article
    • Bacterial Response to Permafrost Derived Organic Matter Input in an Arctic Fjord 

      Müller, Oliver; Seuthe, Lena; Bratbak, Gunnar; Paulsen, Maria Lund (Frontiers, 2018-08-06)
      The warming of the Arctic causes increased riverine discharge, coastal erosion, and the thawing of permafrost. Together, this is leading to an increased wash out of terrestrial dissolved organic matter (tDOM) into the ...
      Journal article
    • Biological transformation of Arctic dissolved organic matter in a NE Greenland fjord 

      Paulsen, Maria Lund; Müller, Oliver; Larsen, Aud; Møller, Eva Friis; Middelboe, Mathias; Sejr, Mikael Kristian; Stedmon, Colin A. (Wiley, 2018-12-07)
      Arctic waters are often enriched with terrestrial dissolved organic matter (DOM) characterized by having elevated visible wavelength fluorescence (commonly termed humic-like). Here, we have identified the sources ...
      Journal article
    • Carbon Bioavailability in a High Arctic Fjord Influenced by Glacial Meltwater, NE Greenland 

      Paulsen, Maria Lund; Nielsen, Sophia Elisabeth Bardram; Müller, Oliver; Møller, Eva Friis; Stedmon, Colin A.; Juul-Pedersen, Thomas; Markager, Stiig; Sejr, Mikael Kristian; Delgado Huertas, Antonio; Larsen, Aud; Middelboe, Mathias (Frontiers, 2017-06-08)
      The land-to-ocean flux of organic carbon is increasing in glacierized regions in response to increasing temperatures in the Arctic (Hood et al., 2015). In order to understand the response of the coastal ecosystem metabolism ...
      Journal article
    • Heterogeneous distribution of plankton within the mixed layer and its implications for bloom formation in tropical seas 

      Calbet, Albert; Agersted, Mette Dalgaard; Kaartvedt, Stein; Møhl, Malene; Møller, Eva Friis; Enghoff-Poulsen, Søren; Paulsen, Maria Lund; Solberg, Ingrid; Tang, Kam W.; Tönnesson, Kajsa; Raitsos, Dionysios E.; Nielsen, Torkel Gissel (Nature Publishing Group, 2015-06-11)
      Intensive sampling at the coastal waters of the central Red Sea during a period of thermal stratification, prior to the main seasonal bloom during winter, showed that vertical patches of prokaryotes and microplankton ...
      Journal article
    • Heterotrophic nanoflagellate grazing facilitates subarctic Atlantic spring bloom development 

      Paulsen, Maria Lund; Riisgård, Karen; St. John, Mike; Thingstad, T. Frede; Nielsen, Torkel Gissel (Inter Research, 2017)
      The subarctic Atlantic phytoplankton spring bloom is one of the largest biological features of the ocean; however, processes initiating the bloom are still not well understood. We hypothesize that the microbial grazing ...
      Journal article
    • Microbial dynamics in high latitude ecosystems. Responses to mixing, runoff and seasonal variation a rapidly changing environment 

      Paulsen, Maria Lund (The University of Bergen, 2017-11-08)
      The pronounced warming at high latitude alters a range of physical conditions i.e. the magnitude of runoff, sea-ice extent and strength of stratification and thus affect the biological systems. As microorganisms form the ...
      Doctoral thesis
    • Phytoplankton dynamics in contrasting early stage North Atlantic spring blooms: composition, succession, and potential drivers 

      Daniels, Chris; Poulton, Alex J.; Mario, Esposito; Paulsen, Maria Lund; Bellerby, Richard; St. John, Mike; Martin, Adrian P. (Copernicus PublicationsEuropean Geosciences Union, 2015-04-24)
      The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little ...
      Journal article
    • A simple adjustment to test reliability of bacterivory rates derived from the dilution method 

      Pree, Bernadette; Kuhlisch, Constanze; Pohnert, Georg; Sazhin, Andrey; Jakobsen, Hans Henrik; Paulsen, Maria Lund; Frischer, Marc E.; Stoecker, Diane K.; Nejstgaard, Jens C.; Larsen, Aud (Wiley, 2016-02)
      Quantification of grazing losses of marine heterotrophic bacteria is critical for understanding nutrient and carbon pathways in aquatic systems. The dilution method is a commonly used experimental approach for quantifying ...
      Journal article
    • Spatiotemporal Dynamics of Ammonia-Oxidizing Thaumarchaeota in Distinct Arctic Water Masses 

      Müller, Oliver; Wilson, Bryan; Paulsen, Maria Lund; Rumińska, Agnieszka; Armo, Hilde R.; Bratbak, Gunnar; Øverås, Lise (Frontiers, 2018-01-23)
      One of the most abundant archaeal groups on Earth is the Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in the biogeochemical cycling of nitrogen. Their universal ...
      Journal article
    • Synechococcus in the Atlantic Gateway to the Arctic Ocean 

      Paulsen, Maria Lund; Doré, Hugo; Garczarek, Laurence; Seuthe, Lena; Müller, Oliver; Sandaa, Ruth-Anne; Bratbak, Gunnar; Larsen, Aud (Frontiers, 2016-10-05)
      Increasing temperatures, with pronounced effects at high latitudes, have raised questions about potential changes in species composition, as well as possible increased importance of small-celled phytoplankton in marine ...
      Journal article
    • Winter−spring transition in the subarcticAtlantic: microbial response to deep mixingand pre-bloom production 

      Paulsen, Maria Lund; Riisgaard, Karen; Frede, Thingstad; St. John, Mike; Nielsen, Torkel Gissel (Inter-Research Science Center (IR), 2015-09-23)
      In temperate, subpolar and polar marine systems, the classical perception is that diatoms initiate the spring bloom and thereby mark the beginning of the productive season. Contrary to this view, we document an active ...
      Journal article