Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ice

• Published in: Scientific Reports
• Main Authors: Assmy, Philipp, Fernández-Méndez, Mar, Duarte, Pedro, Meyer, Amelie, Randelhoff, Achim, Mundy, Christopher J., Olsen, Lasse M., Kauko, Hanna M., Bailey, Allison, Chierici, Melissa, Cohen, Lana, Doulgeris, Anthony P., 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, Zoé, Kwasniewski, Slawomir, Laney, Samuel R., Nicolaus, 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, Jozef, Wagner, Penelope M., Wold, Anette, Steen, Harald, Granskog, Mats A.
• Other Authors: Norwegian Polar Institute, The Arctic University of Norway Tromsø, Norway (UiT), Centre for Earth Observation Science Winnipeg, University of Manitoba Winnipeg, Institute of Marine Research Bergen (IMR), University of Bergen (UiB), Norwegian Meteorological Institute Oslo (MET), Norwegian University of Science and Technology Trondheim (NTNU), Norwegian University of Science and Technology (NTNU), The University Centre in Svalbard (UNIS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Austral, Boréal et Carbone (ABC), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Polish Academy of Sciences (PAN), Woods Hole Oceanographic Institution (WHOI), Alfred Wegener Institute for Polar and Marine Research (AWI), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, ERDC Cold Regions Research and Engineering Laboratory (CRREL), USACE Engineer Research and Development Center (ERDC), Institute of Environmental Physics Bremen (IUP), University of Bremen, Geophysical Institute Bergen (GFI / BiU), Department of Physics and Technology Bergen (UiB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; Arctic; Arctic Ocean; Phytoplankton; Sea ice
• Online Access: https://hal.science/hal-01498849; https://hal.science/hal-01498849/document; https://hal.science/hal-01498849/file/srep40850.pdf; https://doi.org/10.1038/srep40850

International audience 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 that satellite-based Arctic annual primary production estimates may be significantly underestimated. Here we present a unique time-series of a phytoplankton spring bloom observed beneath snow-covered Arctic pack ice. The bloom, dominated by the haptophyte algae Phaeocystis pouchetii, caused near depletion of the surface nitrate inventory and a decline in dissolved inorganic carbon by 16 ± 6 g C m −2 . Ocean circulation characteristics in the area indicated that the bloom developed in situ despite the snow-covered sea ice. Leads in the dynamic ice cover provided added sunlight necessary to initiate and sustain the bloom. Phytoplankton blooms beneath snow-covered ice might become more common and widespread in the future Arctic Ocean with frequent lead formation due to thinner and more dynamic sea ice despite projected increases in high-Arctic snowfall. This could alter productivity, marine food webs and carbon sequestration in the Arctic Ocean. Annual phytoplankton net primary production in the Arctic Ocean has increased by 30% since the late 1990's mainly due to the declining sea ice extent and an increasing phytoplankton growth season 1. However, there is considerable uncertainty about the future change in Arctic Ocean primary productivity largely attributed to the