• Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone 

      Singh, Asmita; Fietz, Susanne; Thomalla, Sandy J.; Sanchez, Nicolas; Ardelan, Murat V.; Moreau, Sebastian; Kauko, Hanna Maria; Fransson, Agneta; Chierici, Melissa; Samanta, Saumik; Mtshali, Thato N.; Roychoudhury, Alakendra N.; Ryan-Keogh, Thomas J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-31)
      he high nutrient–low chlorophyll condition of the Southern Ocean is generally thought to be caused by the low bioavailability of micronutrients, particularly iron, which plays an integral role in phytoplankton photosynthesis. Nevertheless, the Southern Ocean experiences seasonal blooms that generally initiate in austral spring, peak in summer, and extend into autumn. This seasonal increase in primary ...
    • Borealization of the Arctic Ocean in response to anomalous advection from sub-Arctic seas. 

      Polyakov, Igor V.; Alkire, Mattew; Bluhm, Bodil; Brown, Kristina; Carmack, Eddy C.; Chierici, Melissa; Danielson, Seth L.; Ellingsen, Ingrid H.; Ershova, Elizaveta; Gardfeldt, Katrin; Ingvaldsen, Randi Brunvær; Pnyushkov, Andrey V.; Slagstad, Dag; Wassmann, Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-03)
      An important yet still not well documented aspect of recent changes in the Arctic Ocean is associated with the advection of anomalous sub-Arctic Atlantic- and Pacific-origin waters and biota into the polar basins, a process which we refer to as borealization. Using a 37-year archive of observations (1981–2017) we demonstrate dramatically contrasting regional responses to atlantification (that part ...
    • Climate change impacts on sea-ice ecosystems and associated ecosystem services 

      Steiner, Nadja S.; Bowman, Jeff; Campbell, Karley; Chierici, Melissa; Eronen-Rasimus, Eeva; Falardeau, Marianne; Flores, Hauke; Fransson, Agneta; Herr, Helena; Insley, Stephen J.; Kauko, Hanna M.; Lannuzel, Delphine; Loseto, Lisa; Lynnes, Amanda; Majewski, Andy; Meiners, Klaus M.; Miller, Lisa A.; Michel, Loïc N.; Moreau, Sebastien; Nacke, Melissa; Nomura, Daiki; Tedesco, Letizia; van Franeker, Jan Andries; van Leeuwe, Maria A.; Wongpan, Pat (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-13)
      A rigorous synthesis of the sea-ice ecosystem and linked ecosystem services highlights that the sea-ice ecosystem supports all 4 ecosystem service categories, that sea-ice ecosystems meet the criteria for ecologically or biologically significant marine areas, that global emissions driving climate change are directly linked to the demise of sea-ice ecosystems and its ecosystem services, and that the ...
    • Climate change impacts on sea-ice ecosystems and associated ecosystem services 

      Steiner, Nadja; Bowman, Jeff; Campbell, Karley; Chierici, Melissa; Eronen-Rasimus, Eeva; Falardeau, Marianne; Flores, Hauke; Fransson, Agneta; Herr, Helena; Insley, Stephen J.; Kauko, Hanna Maria; Lannuzel, Delphine; Loseto, Lisa; Lynnes, Amanda; Majewski, Andy; Meiners, Klaus M.; Miller, Lisa; Michel, Loic; Moreau, Sebastien; Nacke, Melissa; Nomura, Daiki; Tedesco, Letizia; van Franeker, Jan Andries; Leeuwe, Maria van; Wongpan, Pat (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-13)
      A rigorous synthesis of the sea-ice ecosystem and linked ecosystem services highlights that the sea-ice ecosystem supports all 4 ecosystem service categories, that sea-ice ecosystems meet the criteria for ecologically or biologically significant marine areas, that global emissions driving climate change are directly linked to the demise of sea-ice ecosystems and its ecosystem services, and that the ...
    • CO2 flux over young and snow-covered Arctic pack ice in winter and spring 

      Nomura, Daiki; Granskog, Mats A.; Fransson, Agneta; Chierici, Melissa; Silyakova, Anna; Ohshima, Kay; Cohen, Lana; Delille, Bruno; Hudson, Stephen R.; Dieckmann, Gerhard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-05)
      Rare CO2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is characterized by high salinity and high porosity, and snow-covered thick ice remains relatively warm ( >  −7.5 °C) ...
    • Development, productivity, and seasonality of living planktonic foraminiferal faunas and Limacina helicina in an area of intense methane seepage in the Barents Sea 

      Ofstad, Siri; Meilland, Julie; Zamelczyk, Katarzyna; Chierici, Melissa; Fransson, Agneta; Gründger, Friederike; Rasmussen, Tine Lander (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-09)
      Although the plankton communities in the Barents Sea have been intensely studied for decades, little is known about the living planktonic foraminiferal (LPF) and pteropod faunas, especially those found at methane seep sites. Along a repeated transect in the “crater area” (northern Barents Sea, 74.9°N, 27.7°E) in spring and summer 2016 the flux of LPF and of the pteropod species <i>Limacina helicina</i> ...
    • Diffusive and advective cross-frontal fluxes of inorganic nutrients and dissolved inorganic carbon in the Barents Sea in autumn 

      Koenig, Zoe Charlotte; Fer, Ilker; Chierici, Melissa; Fransson, Agneta; Jones, Elizabeth Marie; Kolås, Eivind Hugaas (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-21)
      The Atlantic Water, entering the Arctic through the Barents Sea and Fram Strait, is the main source of nutrients in the Arctic Ocean. The Barents Sea is divided by the Polar Front into an Atlantic-dominated domain in the south, and an Arctic-dominated domain in the north. The Polar Front is a thermohaline structure, which is topographically-steered at sub-surface, and influenced by the seasonal ...
    • Distribution and Abundances of Planktic Foraminifera and Shelled Pteropods During the Polar Night in the Sea-Ice Covered Northern Barents Sea 

      Zamelczyk, Katarzyna; Fransson, Agneta; Chierici, Melissa; Jones, Elizabeth Marie; Meilland, Julie; Anglada-Ortiz, Griselda; Hodal Lødemel, Helene (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-22)
      Planktic foraminfera and shelled pteropods are important calcifying groups of zooplankton in all oceans. Their calcium carbonate shells are sensitive to changes in ocean carbonate chemistry predisposing them as an important indicator of ocean acidification. Moreover, planktic foraminfera and shelled pteropods contribute significantly to food webs and vertical flux of calcium carbonate in polar pelagic ...
    • Earlier sea-ice melt extends the oligotrophic summer period in the Barents Sea with low algal biomass and associated low vertical flux 

      Kohlbach, Doreen; Goraguer, Lucie; Bodur, Yasemin V.; Müller, Oliver; Amargant Arumí, Martí; Blix, Katalin; Bratbak, Gunnar; Chierici, Melissa; Dabrowska, Anna Maria; Dietrich, Ulrike; Edvardsen, Bente; Garcia, Laura; Gradinger, Rolf Rudolf; Hop, Haakon; Jones, Elizabeth Marie; Øyvind, Lundesgaard; Olsen, Lasse Mork; Reigstad, Marit; Saubrekka, Karoline; Tatarek, Agnieszka; Wiktor, Josef Maria; Wold, Anette; Assmy, Philipp (Journal article; Tidsskriftartikkel, 2023-03-27)
      The decrease in Arctic sea-ice extent and thickness as a result of global warming will impact the timing, duration, magnitude and composition of phytoplankton production with cascading effects on Arctic marine food-webs and biogeochemical cycles. Here, we elucidate the environmental drivers shaping the composition, abundance, biomass, trophic state and vertical flux of protists (unicellular eukaryotes), ...
    • Early spring subglacial discharge plumes fuel under-ice primary production at a Svalbard tidewater glacier 

      Vonnahme, Tobias; Persson, Emma; Dietrich, Ulrike; Hejdukova, Eva; Dybwad, Christine; Elster, Josef; Chierici, Melissa; Gradinger, Rolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-27)
      Subglacial upwelling of nutrient-rich bottom water is known to sustain elevated summer primary production in tidewater-glacier-influenced fjord systems. However, the importance of subglacial upwelling during the early spring season has not been considered yet. We hypothesized that subglacial discharge under sea ice is present in early spring and that its flux is sufficient to increase phytoplankton ...
    • Effect of glacial drainage water on the CO2 system and ocean acidification state in an Arctic tidewater-glacier fjord during two contrasting years 

      Fransson, Agneta Ingrid; Chierici, Melissa; Nomura, Daiki; Granskog, Mats A.; Kristiansen, Svein; Martma, Tõnu; Nehrke, Gernot (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-03)
      In order to investigate the effect of glacial water on the CO<sub>2</sub> system in the fjord, we studied the variability of the total alkalinity (A<sub>T</sub>), total dissolved inorganic carbon (C<sub>T</sub>), dissolved inorganic nutrients, oxygen isotopic ratio (δ<sup>18</sup>O), and freshwater fractions from the glacier front to the outer Tempelfjorden on Spitsbergen in winter 2012 (January, ...
    • Episodic Arctic CO2 Limitation in the West Svalbard Shelf 

      Sanz-Martín, Marina; Chierici, Melissa; Mesa, Elena; Carrillo-de-Albornoz, Paloma; Delgado-Huertas, Antonio; Agusti, Susana; Reigstad, Marit; Kristiansen, Svein; Wassmann, Paul; Duarte, Carlos M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-06)
      The European Sector of the Arctic Ocean is characterized by low CO<sub>2</sub> concentrations in seawater during spring and summer, largely due to strong biological uptake driven by extensive plankton blooms in spring. The spring plankton bloom is eventually terminated by nutrient depletion and grazing. However, low CO<sub>2</sub> concentrations in seawater and low atmospheric resupply of CO<sub>2</sub> ...
    • From Winter to Late Summer in the Northwestern Barents Sea Shelf: Impacts of Seasonal Progression of Sea Ice and Upper Ocean on Nutrient and Phytoplankton Dynamics 

      Koenig, Zoe Charlotte; Muilwijk, Morven; Sandven, Håkon Johan; Lundesgaard, Øyvind; Assmy, Philipp Kurt Wolf; Lind, Sigrid Gjessing; Assmann, Karen; Chierici, Melissa; Fransson, Agneta; Gerland, Sebastian; Jones, Elizabeth Marie; Renner, Angelika; Granskog, Mats (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-11)
      Strong seasonality is a key feature of high-latitude systems like the Barents Sea. While the interannual variability and long-term changes of the Barents Sea are well-documented, the seasonal progression of the physical and biological systems is less known, mainly due to poor accessibility of the seasonally ice-covered area in winter and spring. Here, we use an extensive set of physical and biological ...
    • The future of Arctic sea-ice biogeochemistry and ice-associated ecosystems 

      Lannuzel, Delphine; Tedesco, Letizia; Leeuwe, Maria van; Campbell, Karley; Flores, Hauke; Delille, Bruno; Miller, Lisa; Stefels, Jacqueline; Assmy, Philipp; Bowman, Jeff; Brown, Kristina; Castellani, Giulia; Chierici, Melissa; Crabeck, Odile; Damm, Ellen; Else, Brent; Fransson, Agneta; Fripiat, Francois; Geilfus, Nicolas-Xavier; Jacques, Caroline; Jones, Elizabeth; Kaartokallio, Hermanni; kotovitch, marie; Meiners, Klaus M.; Moreau, Sebastien; Nomura, Daiki; Peeken, Ilka; Rintala, Janne-Markus; Steiner, Nadja; Tison, Jean-Louis; Vancoppenolle, Martin; Linden, Fanny Van der; Vichi, Marcello; Wongpan, Pat (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-27)
      The Arctic sea-ice-scape is rapidly transforming. Increasing light penetration will initiate earlier seasonal primary production. This earlier growing season may be accompanied by an increase in ice algae and phytoplankton biomass, augmenting the emission of dimethylsulfide and capture of carbon dioxide. Secondary production may also increase on the shelves, although the loss of sea ice exacerbates ...
    • Hydrography, inorganic nutrients and chlorophyll a linked to sea ice cover in the Atlantic Water inflow region north of Svalbard 

      Renner, Angelika; Bailey, Allison Michelle; Reigstad, Marit; Sundfjord, Arild; Chierici, Melissa; Jones, Elizabeth Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-04)
      Changes in the inflow of Atlantic Water (AW) and its properties to the Arctic Ocean bring more warm water, contribute to sea ice decline, promote borealisation of marine ecosystems, and affect biological and particularly primary productivity in the Eurasian Arctic Ocean. One of the two branches of AW inflow follows the shelf break north of Svalbard, where it dominates oceanographic conditions, ...
    • Influence of glacial water and carbonate minerals on wintertime sea-ice biogeochemistry and the CO2 system in an Arctic fjord in Svalbard 

      Fransson, Agneta; Chierici, Melissa; Nomura, Daiki; Granskog, Mats; Kristiansen, Svein; Martma, Tõnu; Nehrke, Gernot (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-13)
      The effect of freshwater sources on wintertime sea-ice CO2 processes was studied from the glacier front to the outer Tempelfjorden, Svalbard, in sea ice, glacier ice, brine and snow. March–April 2012 was mild, and the fjord was mainly covered with drift ice, in contrast to the observed thicker fast ice in the colder April 2013. This resulted in different physical and chemical properties of the sea ...
    • Interannual differences in sea ice regime in the north-western Barents Sea cause major changes in summer pelagic production and export mechanisms 

      Amargant I Arumi, Marti; Müller, Oliver; Bodur, Yasemin Vicdan; Ntinou, Iliana Vasiliki; Vonnahme, Tobias; Assmy, Philipp Kurt Wolf; Kohlbach, Doreen; Chierici, Melissa; Jones, Elizabeth Marie; Olsen, Lasse Mork; Tsagaraki, Tatiana; Reigstad, Marit; Bratbak, Gunnar; Gradinger, Rolf Rudolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-22)
      The Barents Sea is a highly dynamic and productive marine ecosystem and a hotspot of global warming. Variability in sea ice extent is a common feature in the Barents Sea with substantial movements of the sea ice edge on short-term, seasonal to interannual time scales. Historically the northern Barents Sea (north of 75◦N) has been ice-covered in winter, but recently it has become the area with most ...
    • Large-scale culturing of Neogloboquadrina pachyderma, its growth in, and tolerance of, variable environmental conditions 

      Westgård, Adele; Mohamed, Mohamed Mahmoud Ezat Ahmed; Chalk, Tom; Chierici, Melissa; Foster, Gavin L.; Meilland, Julie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-09)
      The planktic foraminifera Neogloboquadrina pachyderma is a calcifying marine protist and the dominant planktic foraminifera species in the polar oceans, making it a key species in marine polar ecosystems. The calcium carbonate shells of foraminifera are widely used in palaeoclimate studies because their chemical composition reflects the seawater conditions in which they grow. This species provides ...
    • The last two millennia: climate, ocean circulation and paleoproductivity inferred from planktic foraminifera, south-western Svalbard margin 

      Zamelczyk, Katarzyna; Rasmussen, Tine Lander; Raitzsch, Markus; Chierici, Melissa (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-20)
      We reconstruct climate and changes in water-mass properties in relation to variations in palaeoproductivity at the south-western Svalbard margin throughout the last 2000 years. Environmental conditions in subsurface (ca. 250–75 m) and near-surface to surface water (75–0 m) were studied on the basis of the distribution patterns and fluxes of planktic foraminiferal faunas. Stable isotopes in three ...
    • Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic 

      Assmy, Philipp; Fernández-Méndez, Mar; Duarte, Pedro; Meyer, Amelie; Randelhoff, Achim; Mundy, Christopher John; Olsen, Lasse; Kauko, Hanna M.; Bailey, Allison; Chierici, Melissa; Cohen, Lana; Doulgeris, Anthony Paul; Ehn, Jens K.; Fransson, Agneta; Gerland, Sebastian; Hop, Haakon; Hudson, Stephen R.; Hughes, Nick; Itkin, Polona; Johnsen, Geir; King, Jennifer A.; Koch, Boris P.; Koenig, Zoe; Kwasniewski, Slawomir; Laney, Samuel R.; Nikolaus, Marcel; Pavlov, Alexey K.; Polashenski, Christopher M.; Provost, Christine; Rösel, Anja; Sandbu, Marthe; Spreen, Gunnar; Smedsrud, Lars H.; Sundfjord, Arild; Taskjelle, Torbjørn; Tatarek, Agnieszka; Wiktor, Josef; Wagner, Penelope Mae; Wold, Anette; Steen, Harald; Granskog, Mats A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-19)
      The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms beneath ponded sea ice during summer, indicating ...