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17 results on '"C J, Mundy"'

1. Vertical distributions of organic matter components in sea ice near Cambridge Bay, Dease Strait, Canadian Archipelago

Author

Kwanwoo Kim, Sun-Yong Ha, Kyung-Hoon Shin, Jee-Hoon Kim, C. J. Mundy, Laura A. Dalman, Bo Kyung Kim, Dabin Lee, Hyo Keun Jang, Yejin Kim, Sanghoon Park, and Sang Heon Lee

Subjects
sea ice, organic matters, Chl-a (chlorophyll a), biopolymeric carbon (BPC), Cambridge Bay, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Ice algae thriving within sea ice play a crucial role in transferring energy to higher trophic levels and influencing biogeochemical processes in polar oceans; however, the distribution of organic matter within the ice interior is not well understood. This study aimed to investigate the vertical distribution of organic matter, including chlorophyll a (Chl-a), particulate organic carbon and nitrogen (POC and PON), carbohydrates (CHO), proteins (PRT), lipids (LIP), and food material (FM), within the sea ice. Samples were collected from the bottom, middle, and top sections of the sea ice column near Cambridge Bay during the spring of 2018. Based on the δ13C signature, biochemical composition, and POC contribution of biopolymeric carbon (BPC), the organic substances within the sea ice were predominantly attributed to marine autotrophs. While the highest concentrations of each parameter were observed at the sea ice bottom, notable concentrations were also found in the upper sections. The average sea ice column-integrated Chl-a concentration was 5.05 ± 2.26 mg m−2, with the bottom ice section contributing 59% (S.D. = ± 10%) to the total integration. The column-integrated concentrations of FM, BPC, POC, and PON were 2.05 ± 0.39, 1.10 ± 0.20, 1.47 ± 0.25, and 0.09 ± 0.03 g m−2, respectively. Contributions of the bottom ice section to these column-integrated concentrations varied for each parameter, with values of 20 ± 6, 21 ± 7, 19 ± 5, and 28 ± 7%, respectively. While the bottom ice section exhibited a substantial Chl-a contribution in line with previous studies, significantly higher contributions of the other parameters were observed in the upper sea ice sections. This suggests that the particulate matter within the interior of the sea ice could potentially serve as an additional food source for higher trophic grazers or act as a seeding material for a phytoplankton bloom during the ice melting season. Our findings highlight the importance of comprehensive field measurements encompassing the entire sea ice section to better understand the distribution of organic carbon pools within the sea ice in the Arctic Ocean.

Published
2023
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2. Under-Ice Phytoplankton Blooms: Shedding Light on the 'Invisible' Part of Arctic Primary Production

Author

Mathieu Ardyna, C. J. Mundy, Nicolas Mayot, Lisa C. Matthes, Laurent Oziel, Christopher Horvat, Eva Leu, Philipp Assmy, Victoria Hill, Patricia A. Matrai, Matthew Gale, Igor A. Melnikov, and Kevin R. Arrigo

Subjects
under-ice phytoplankton blooms, biogeochemical cycles, nutrient, sea ice, climate change, Arctic Ocean, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

The growth of phytoplankton at high latitudes was generally thought to begin in open waters of the marginal ice zone once the highly reflective sea ice retreats in spring, solar elevation increases, and surface waters become stratified by the addition of sea-ice melt water. In fact, virtually all recent large-scale estimates of primary production in the Arctic Ocean (AO) assume that phytoplankton production in the water column under sea ice is negligible. However, over the past two decades, an emerging literature showing significant under-ice phytoplankton production on a pan-Arctic scale has challenged our paradigms of Arctic phytoplankton ecology and phenology. This evidence, which builds on previous, but scarce reports, requires the Arctic scientific community to change its perception of traditional AO phenology and urgently revise it. In particular, it is essential to better comprehend, on small and large scales, the changing and variable icescapes, the under-ice light field and biogeochemical cycles during the transition from sea-ice covered to ice-free Arctic waters. Here, we provide a baseline of our current knowledge of under-ice blooms (UIBs), by defining their ecology and their environmental setting, but also their regional peculiarities (in terms of occurrence, magnitude, and assemblages), which is shaped by a complex AO. To this end, a multidisciplinary approach, i.e., combining expeditions and modern autonomous technologies, satellite, and modeling analyses, has been used to provide an overview of this pan-Arctic phenological feature, which will become increasingly important in future marine Arctic biogeochemical cycles.

Published
2020
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3. Environmental drivers of under-ice phytoplankton bloom dynamics in the Arctic Ocean

Author

Mathieu Ardyna, C. J. Mundy, Matthew M. Mills, Laurent Oziel, Pierre-Luc Grondin, Léo Lacour, Gauthier Verin, Gert Van Dijken, Joséphine Ras, Eva Alou-Font, Marcel Babin, Michel Gosselin, Jean-Éric Tremblay, Patrick Raimbault, Philipp Assmy, Marcel Nicolaus, Hervé Claustre, and Kevin R. Arrigo

Subjects
under-ice phytoplankton blooms, biogeochemical cycles, nutrients, sea ice, climate change, arctic ocean, Environmental sciences, GE1-350
Abstract

The decline of sea-ice thickness, area, and volume due to the transition from multi-year to first-year sea ice has improved the under-ice light environment for pelagic Arctic ecosystems. One unexpected and direct consequence of this transition, the proliferation of under-ice phytoplankton blooms (UIBs), challenges the paradigm that waters beneath the ice pack harbor little planktonic life. Little is known about the diversity and spatial distribution of UIBs in the Arctic Ocean, or the environmental drivers behind their timing, magnitude, and taxonomic composition. Here, we compiled a unique and comprehensive dataset from seven major research projects in the Arctic Ocean (11 expeditions, covering the spring sea-ice-covered period to summer ice-free conditions) to identify the environmental drivers responsible for initiating and shaping the magnitude and assemblage structure of UIBs. The temporal dynamics behind UIB formation are related to the ways that snow and sea-ice conditions impact the under-ice light field. In particular, the onset of snowmelt significantly increased under-ice light availability (>0.1–0.2 mol photons m–2 d–1), marking the concomitant termination of the sea-ice algal bloom and initiation of UIBs. At the pan-Arctic scale, bloom magnitude (expressed as maximum chlorophyll a concentration) was predicted best by winter water Si(OH)4 and PO43– concentrations, as well as Si(OH)4:NO3– and PO43–:NO3– drawdown ratios, but not NO3– concentration. Two main phytoplankton assemblages dominated UIBs (diatoms or Phaeocystis), driven primarily by the winter nitrate:silicate (NO3–:Si(OH)4) ratio and the under-ice light climate. Phaeocystis co-dominated in low Si(OH)4 (i.e., NO3:Si(OH)4 molar ratios >1) waters, while diatoms contributed the bulk of UIB biomass when Si(OH)4 was high (i.e., NO3:Si(OH)4 molar ratios

Published
2020
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4. Melt Procedure Affects the Photosynthetic Response of Sea Ice Algae

Author

Karley Campbell, C. J. Mundy, Andrew R. Juhl, Laura A. Dalman, Christine Michel, Ryan J. Galley, Brent E. Else, Nicolas X. Geilfus, and Søren Rysgaard

Subjects
sea ice, algae, salinity stress, photophysiology, sample melt, Arctic, Science
Abstract

The accuracy of sea ice algal production estimates is influenced by the range of melting procedures used in studies to obtain a liquid sample for incubation, particularly in relation to the duration of melt and the approach to buffering for osmotic shock. In this research, ice algal photophysiology from 14C incubations was compared in field samples prepared by three melt procedures: (i) a rapid ≤ 4 h melt of the bottommost ( < 1 cm) ice algal layer scraped into a large volume of filtered seawater (salinity 27–30), (ii) melt of a bottom 5 cm section diluted into a moderate volume of filtered seawater over 24 h (salinity 20–24), and (iii) melt of a bottom 5 cm section without any filtered seawater dilution over about 48 h (salinity 10–12). Maximum photosynthetic rate, photosynthetic efficiency and production at zero irradiance were significantly affected by the melt treatment employed in experiments. All variables were greatest in the highly diluted scrape sample and lowest in the bulk-ice samples melted in the absence of filtered seawater. Laboratory experiments exposing cultures of the common sea ice diatom Nitzschia frigida to different salinities and light conditions suggested that the field-based responses can be attributed to the rapid ( < 4 h) adverse effects of exposing cells to low salinities during melt without dilution. The observed differences in primary production between melt treatments were estimated to account for over 60% of the variability in production estimates reported for the Arctic. Future studies are strongly encouraged to replicate salinity conditions representative of in situ values during the melting process to minimize hypoosmotic stress, thereby most accurately estimating primary production.

Published
2019
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5. Green Edge ice camp campaigns: understanding the processes controlling the under-ice Arctic phytoplankton spring bloom

Author

P. Massicotte, R. Amiraux, M.-P. Amyot, P. Archambault, M. Ardyna, L. Arnaud, L. Artigue, C. Aubry, P. Ayotte, G. Bécu, S. Bélanger, R. Benner, H. C. Bittig, A. Bricaud, É. Brossier, F. Bruyant, L. Chauvaud, D. Christiansen-Stowe, H. Claustre, V. Cornet-Barthaux, P. Coupel, C. Cox, A. Delaforge, T. Dezutter, C. Dimier, F. Domine, F. Dufour, C. Dufresne, D. Dumont, J. Ehn, B. Else, J. Ferland, M.-H. Forget, L. Fortier, M. Galí, V. Galindo, M. Gallinari, N. Garcia, C. Gérikas Ribeiro, M. Gourdal, P. Gourvil, C. Goyens, P.-L. Grondin, P. Guillot, C. Guilmette, M.-N. Houssais, F. Joux, L. Lacour, T. Lacour, A. Lafond, J. Lagunas, C. Lalande, J. Laliberté, S. Lambert-Girard, J. Larivière, J. Lavaud, A. LeBaron, K. Leblanc, F. Le Gall, J. Legras, M. Lemire, M. Levasseur, E. Leymarie, A. Leynaert, A. Lopes dos Santos, A. Lourenço, D. Mah, C. Marec, D. Marie, N. Martin, C. Marty, S. Marty, G. Massé, A. Matsuoka, L. Matthes, B. Moriceau, P.-E. Muller, C.-J. Mundy, G. Neukermans, L. Oziel, C. Panagiotopoulos, J.-J. Pangrazi, G. Picard, M. Picheral, F. Pinczon du Sel, N. Pogorzelec, I. Probert, B. Quéguiner, P. Raimbault, J. Ras, E. Rehm, E. Reimer, J.-F. Rontani, S. Rysgaard, B. Saint-Béat, M. Sampei, J. Sansoulet, C. Schmechtig, S. Schmidt, R. Sempéré, C. Sévigny, Y. Shen, M. Tragin, J.-É. Tremblay, D. Vaulot, G. Verin, F. Vivier, A. Vladoiu, J. Whitehead, M. Babin, Asian School of the Environment, Takuvik Joint ULaval/CNRS Laboratory, Centre National de la Recherche Scientifique (CNRS)-Laval University [Québec], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université du Québec à Rimouski (UQAR), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Earth System Science [Stanford] (ESS), Stanford University [Stanford], Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), CHU de Québec–Université Laval, Laval University [Québec], Department of Biological Sciences [Columbia], University of South Carolina [Columbia], Institut méditerranéen d'océanologie (MIO), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Adaptation et diversité en milieu marin (ADMM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la MER de Rimouski (ISMER), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Dept Biologie, Université Laval, Université Laval, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Université de Lille-Université du Littoral Côte d'Opale-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Variabilité de l'Océan et de la Glace de mer (VOG), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Division de la productivité des Océans (Ministère des Pêches et des Océans), Institut Maurice-Lamontagne, Diversité et Interactions au sein du Plancton Océanique (DIPO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), ECOlogy of MArine Plankton (ECOMAP), Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Développement Instrumental et Techniques Marines (DITM), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Technologie de Belfort-Montbeliard (UTBM), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines (LMGEM), Centre National de la Recherche Scientifique (CNRS)-Université de la Méditerranée - Aix-Marseille 2, Centre d'études spatiales de la biosphère (CESBIO), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Greenland Institute for Natural Resources (GINR), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie des Plantes (IBP), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Department of Biology [Québec], Processus et interactions de fine échelle océanique (PROTEO), CNES(project#131425)IPEV(project#1164)CSA,FondationTotalArcticNetLEFEFrench Arctic Initiative (GreenEdgeproject), ANR: GreenEdge project,ANR (Contract #111112),Contract #111112, Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Université Laval [Québec] (ULaval), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Stanford EARTH, Stanford University-Stanford University, Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut National de Santé Publique du Québec [Canada] (INSPQ), Département de médecine sociale et préventive [ESPUM-Montréal] (ESPUM), Université de Montréal (UdeM), Departement de Biologie, Chimie et Géographie, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre for Earth Observation Science [Winnipeg], University of Manitoba [Winnipeg], Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Geography [Calgary], University of Calgary, Barcelona Supercomputing Center - Centro Nacional de Supercomputacion (BSC - CNS), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad Mayor [Santiago de Chile], Royal Belgian Institute of Natural Sciences (RBINS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-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)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Physiologie et biotechnologie des Algues (PBA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de recherche du CHU de Québec-Université Laval (CRCHUQ), Université Laval [Québec] (ULaval)-Université Laval [Québec] (ULaval), Institut de Biologie Intégrative et des Systèmes [Québec] (IBIS), Asian School of the Environment (ASE), Nanyang Technological University [Singapour], Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Norwegian Institute for Water Research (NIVA), Faculty of Fisheries Sciences [Hakodate], Hokkaido University [Sapporo, Japan], Observatoire des sciences de l'univers Ecce Terra [Paris] (ECCE TERRA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of the Earth, Ocean and Environment [Columbia] (SEOE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), ANR-14-CE01-0017,Green Edge,Productivité biologique dans l'Océan Arctique: réponse passée, présente et future aux fluctuations climatiques, et impacts sur les flux de carbone, le réseau trophique et les communautés humaines locales(2014), Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre de Toxicologie du Québec (CTQ), Département de médecine sociale et préventive (DMPS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Applied Physics Laboratory [Seattle] (APL-UW), University of Washington [Seattle], Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Observatoire des sciences de l'univers Ecce Terra (ECCE TERRA), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology [2020-....] (Grenoble INP [2020-....]), Université Grenoble Alpes [2020-....] (UGA [2020-....])-Université Grenoble Alpes [2020-....] (UGA [2020-....])-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Université du Littoral Côte d'Opale-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Fédération de recherche de Roscoff (FR2424), Biotechnologies et Ressources Marines (BRM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Observatoire des sciences de l'univers Ecce Terra [Paris] (OSU ECCE TERRA), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)

Subjects
0106 biological sciences, PACIFIC, 010504 meteorology & atmospheric sciences, ZONE, 010501 environmental sciences, Zooplankton, 01 natural sciences, CARBON, ALGAE, OCEAN, Ice Camp, Phytoplankton, Sea ice, Ecosystem, 14. Life underwater, lcsh:Environmental sciences, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:GE1-350, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Arctic studies, ACL, lcsh:QE1-996.5, Biology and Life Sciences, Spring bloom, 15. Life on land, CHLOROPHYLL, IRRADIANCE, Environmental engineering [Engineering], lcsh:Geology, Oceanography, Arctic, 13. Climate action, [SDE]Environmental Sciences, VOLUME, General Earth and Planetary Sciences, Environmental science, Phytoplankton Spring Bloom, SEA-ICE, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract

The Green Edge initiative was developed to investigate the processes controlling the primary productivity and fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797∘ N, 63.7895∘ W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea-ice cover from the surface to the bottom (at 360 m depth) to better understand the factors driving the PSB. Key variables, such as conservative temperature, absolute salinity, radiance, irradiance, nutrient concentrations, chlorophyll a concentration, bacteria, phytoplankton and zooplankton abundance and taxonomy, and carbon stocks and fluxes were routinely measured at the ice camp. Meteorological and snow-relevant variables were also monitored. Here, we present the results of a joint effort to tidy and standardize the collected datasets, which will facilitate their reuse in other Arctic studies. The dataset is available at https://doi.org/10.17882/59892 (Massicotte et al., 2019a).

Published
2020
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6. Environmental drivers of spring primary production in Hudson Bay

Author

C. J. Mundy, Jens K. Ehn, Laura A. Dalman, Sergey Kirillov, David G. Barber, Jean-Éric Tremblay, Ilka Peeken, Lisa C. Matthes, D. Babb, Simon Bélanger, J. Lee, and Madison L. Harasyn

Subjects
0106 biological sciences, Atmospheric Science, Chlorophyll a, Environmental Engineering, 010504 meteorology & atmospheric sciences, Oceanography, 01 natural sciences, Algal bloom, chemistry.chemical_compound, Phytoplankton, Sea ice, 14. Life underwater, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Ecology, biology, 010604 marine biology & hydrobiology, Geology, Geotechnical Engineering and Engineering Geology, biology.organism_classification, Diatom, chemistry, Arctic, Environmental science, Bloom, Bay
Abstract

Pertinent environmental factors influencing the microalgal bloom during sea-ice breakup in Hudson Bay were investigated in June 2018, producing the first observations of late spring primary production in the offshore waters of this vast inland sea. Phytoplankton production was found to commence at the onset of ice melt, with surface nutrient depletion leading to the formation of a subsurface chlorophyll maximum in the open waters of western Hudson Bay. Concurrently, the melting mobile ice cover in central Hudson Bay created favorable conditions for a diatom-dominated under-ice bloom, with photosynthetic characteristics and relatively high production confirming that phytoplankton cells were able to acclimate to increasing light levels. Lower mean values of phytoplankton production and total chlorophyll a (TChl a) concentration observed under the sea ice (414 mg C m–2 d–1 and 33.7 mg TChl a m–2) than those observed in open waters during the late bloom stage in the western region (460 mg C m–2 d–1 and 53.5 mg TChl a m–2) were attributed to reduced under-ice light levels and low surface concentrations of dissolved inorganic nitrogen (

Published
2021
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7. Under-ice phytoplankton blooms: Shedding light on the 'invisible' part of Arctic primary production

Author

Lisa C. Matthes, Philipp Assmy, Kevin R. Arrigo, Igor A. Melnikov, Eva Leu, C. J. Mundy, Christopher Horvat, Patricia A. Matrai, Laurent Oziel, Victoria Hill, Mathieu Ardyna, Matthew A. Gale, Nicolas Mayot, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre for Earth Observation Science [Winnipeg], University of Manitoba [Winnipeg], Bigelow Laboratory for Ocean Sciences, University of East Anglia [Norwich] (UEA), Takuvik International Research Laboratory, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), MOM: La meiose dans l'ovocyte des mammifères = MOM: mammalian oocyte meiosis (LBD-E13), Laboratoire de Biologie du Développement [Paris] (LBD), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Paris Seine (IBPS), Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Paris Seine (IBPS), Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Brown University, Akvaplan-Niva [Tromsø], Norwegian Institute for Water Research (NIVA), Norwegian Polar Institute, Old Dominion University [Norfolk] (ODU), P.P. Shirshov Institute of Oceanology (SIO), Russian Academy of Sciences [Moscow] (RAS), Department of Earth System Science [Stanford] (ESS), Stanford EARTH, Stanford University-Stanford University, Gestionnaire, HAL Sorbonne Université 5, Laboratoire de Biologie du Développement [IBPS] (LBD), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Paris Seine (IBPS), and Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDE] Environmental Sciences, 0106 biological sciences, Biogeochemical cycle, lcsh:QH1-199.5, 010504 meteorology & atmospheric sciences, Ecology (disciplines), Climate change, Ocean Engineering, lcsh:General. Including nature conservation, geographical distribution, Aquatic Science, [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, Oceanography, 01 natural sciences, Latitude, Water column, Phytoplankton, Arctic Ocean, Sea ice, 14. Life underwater, lcsh:Science, under-ice phytoplankton blooms, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, nutrient, biogeochemical cycles, sea ice, climate change, Arctic, 13. Climate action, [SDE]Environmental Sciences, Environmental science, lcsh:Q
Abstract

The growth of phytoplankton at high latitudes was generally thought to begin in open waters of the marginal ice zone once the highly reflective sea ice retreats in spring, solar elevation increases, and surface waters become stratified by the addition of sea-ice melt water. In fact, virtually all recent large-scale estimates of primary production in the Arctic Ocean (AO) assume that phytoplankton production in the water column under sea ice is negligible. However, over the past two decades, an emerging literature showing significant under-ice phytoplankton production on a pan-Arctic scale has challenged our paradigms of Arctic phytoplankton ecology and phenology. This evidence, which builds on previous, but scarce reports, requires the Arctic scientific community to change its perception of traditional AO phenology and urgently revise it. In particular, it is essential to better comprehend, on small and large scales, the changing and variable icescapes, the under-ice light field and biogeochemical cycles during the transition from sea-ice covered to ice-free Arctic waters. Here, we provide a baseline of our current knowledge of under-ice blooms (UIBs), by defining their ecology and their environmental setting, but also their regional peculiarities (in terms of occurrence, magnitude, and assemblages), which is shaped by a complex AO. To this end, a multidisciplinary approach, i.e., combining expeditions and modern autonomous technologies, satellite, and modeling analyses, has been used to provide an overview of this pan-Arctic phenological feature, which will become increasingly important in future marine Arctic biogeochemical cycles.

Published
2020
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8. Spatial Heterogeneity as a Key Variable Influencing Spring-Summer Progression in UVR and PAR Transmission Through Arctic Sea Ice

Author

C. J. Mundy, S. L.-Girard, Marcel Babin, G Vérin, Jens K. Ehn, Lisa C. Matthes, Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:QH1-199.5, Arctic sea ice, Ocean Engineering, Aquatic Science, lcsh:General. Including nature conservation, geographical distribution, Oceanography, Atmospheric sciences, UVR, 01 natural sciences, transmittance, Phytoplankton, Melt pond, Sea ice, lcsh:Science, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, under-ice phytoplankton bloom, Albedo, Snow, Arctic ice pack, 13. Climate action, ROV, radiative transfer, Environmental science, Spatial variability, spatial variability, lcsh:Q, Bloom, PAR
Abstract

International audience; The transmission of ultraviolet (UVR) and photosynthetically available radiation (PAR) through sea ice is a key factor controlling under-ice phytoplankton growth in seasonally ice-covered waters. The increase toward sufficient light levels for positive net photosynthesis occurs concurrently with the sea ice melt progression in late spring when ice surface conditions shift from a relatively homogeneous high-albedo snow cover to a less reflective mosaic of bare ice and melt ponds. Here, we present a detailed dataset on the spatial and temporal progression of transmitted UVR and PAR in relation to changing quantities of snow, sea ice and melt ponds. Data were collected with a remotely operated vehicle (ROV) during the GreenEdge landfast sea ice campaign in June–July 2016 in southwestern Baffin Bay. Over the course of melt progression, there was a 10-fold increase in spatially averaged UVR and PAR transmission through the sea ice cover, reaching a maximum transmission of 31% for PAR, 7% for UVB, and 26% for UVA radiation. The depth under the sea ice experiencing spatial variability in light levels due to the influence of surface heterogeneity in snow, white ice and melt pond distributions increased from 7 ± 4 to 20 ± 6 m over our study. Phytoplankton drifting in under-ice surface waters were thus exposed to variations in PAR availability of up to 43%, highlighting the importance to account for spatial heterogeneity in light transmission through melting sea ice. Consequently, we demonstrate that spatial averages of PAR transmission provided more representative light availability estimates to explain under-ice bloom progression relative to single point irradiance measurements during the sea ice melt season. Encouragingly, the strong dichotomy between white ice and melt pond PAR transmittance and surface albedo permitted a very good estimate of spatially averaged light transmission from drone imagery of the surface and point transmittance measurements beneath different ice surface types.

Published
2020
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9. Net community production in the bottom of first-year sea ice over the Arctic spring bloom

Author

Jack C. Landy, Michel Gosselin, Karley Campbell, Søren Rysgaard, Aurelie Delaforge, and C. J. Mundy

Subjects
0106 biological sciences, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, biology, Ecology, 010604 marine biology & hydrobiology, fungi, Heterotroph, Spring bloom, biology.organism_classification, Photosynthesis, 01 natural sciences, Geophysics, Oceanography, Algae, Productivity (ecology), 13. Climate action, Sea ice, General Earth and Planetary Sciences, Environmental science, 14. Life underwater, Autotroph, 0105 earth and related environmental sciences, Trophic level
Abstract

The balance of photosynthesis and respiration by organisms like algae and bacteria determines whether sea ice is net heterotrophic or autotrophic. In turn this clarifies the influence of microbes on atmosphere-ice-ocean gas fluxes, and their contribution to the trophic system. In this study we define two phases of the spring bloom based on bottom-ice net community production and algal growth. Phase I was characterized by limited algal accumulation and low productivity, which at times resulted in net heterotrophy. Greater productivity in Phase II drove rapid algal accumulation that consistently produced net autotrophic conditions. The different phases were associated with seasonal shifts in light availability and species dominance. Results from this study demonstrate the importance of community respiration on spring productivity, as respiration rates can maintain a heterotrophic state independent of algal growth. This challenges previous assumptions of a fully autotrophic sea ice community during the ice-covered spring

Published
2017
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10. Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

Author

Alexey Pavlov, Feiyue Wang, Mar Fernández-Méndez, Mats A. Granskog, Ashley Elliott, Philipp Assmy, Stephen R. Hudson, Lasse Mork Olsen, Hanna M. Kauko, Torbjørn Taskjelle, Geir Johnsen, Pedro Duarte, and C. J. Mundy

Subjects
0106 biological sciences, Drift ice, Atmospheric Science, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Ecology, 010604 marine biology & hydrobiology, Lead (sea ice), Paleontology, Soil Science, Forestry, Antarctic sea ice, Aquatic Science, 01 natural sciences, Arctic ice pack, Oceanography, Sea ice thickness, Melt pond, Sea ice, Cryosphere, Geology, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

The Arctic Ocean is rapidly changing from thicker multiyear to thinner first-year ice cover, with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will possibly result in more frequent leads, covered by newly formed ice with little snow cover. We studied a refrozen lead (≤0.27 m ice) in drifting pack ice north of Svalbard (80.5–82.4 °N) in May-June 2015 during the Norwegian young sea ICE expedition (N-ICE2015). We measured downwelling incident and ice transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)-protecting mycosporine-like amino acids (MAAs) and chlorophyll a (Chl a) in melted sea ice samples. We found occasionally very high MAA concentrations (up to 39 mg m-3, mean 4.5 ± 7.8 mg m-3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modelled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artefacts due to osmotic shock during ice melting. Although observed PAR transmittance through the thin ice was 5–40 times that of the adjacent thicker ice with deep snow cover, ice algal standing stocks were low (≤2.31 mg Chl a m-2) and similar to the adjacent ice. Ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high-light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.

Published
2017
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11. Average cosine coefficient and spectral distribution of the light field under sea ice: Implications for primary production

Author

Nicole M. Pogorzelec, S. L.-Girard, C. J. Mundy, Lisa C. Matthes, Jens K. Ehn, Marcel Babin, University of Manitoba [Winnipeg], Takuvik Joint International Laboratory ULAVAL-CNRS, and Centre National de la Recherche Scientifique (CNRS)-Université Laval [Québec] (ULaval)

Subjects
0106 biological sciences, Atmospheric Science, Under-ice downwelling average cosine, Environmental Engineering, 010504 meteorology & atmospheric sciences, Spectral power distribution, Irradiance, Oceanography, Atmospheric sciences, 01 natural sciences, Under-ice spectral light field, Under-ice PAR propagation, Sea ice melt progression, Spring phytoplankton bloom, Arctic primary production, Downwelling, Sea ice, Melt pond, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Geology, Geotechnical Engineering and Engineering Geology, Snow, 13. Climate action, Photosynthetically active radiation, Snowmelt, Environmental science
Abstract

The Arctic spring phytoplankton bloom has been reported to commence under a melting sea ice cover as transmission of photosynthetically active radiation (PAR; 400–700 nm) suddenly increases with the formation of surface melt ponds. Spatial variability in ice surface characteristics, i.e., snow thickness or melt pond distributions, and subsequent impact on transmitted PAR makes estimating light-limited primary production difficult during this time of year. Added to this difficulty is the interpretation of data from various sensor types, including hyperspectral, multispectral, and PAR-band irradiance sensors, with either cosine-corrected (planar) or spherical (scalar) sensor heads. To quantify the impact of the heterogeneous radiation field under sea ice, spectral irradiance profiles were collected beneath landfast sea ice during the Green Edge ice-camp campaigns in May–June 2015 and June–July 2016. Differences between PAR measurements are described using the downwelling average cosine, μd, a measure of the degree of anisotropy of the downwelling underwater radiation field which, in practice, can be used to convert between downwelling scalar, E0d, and planar, Ed, irradiance. A significantly smallerμd(PAR) was measured prior to snow melt compared to after (0.6 vs. 0.7) when melt ponds covered the ice surface. The impact of the average cosine on primary production estimates, shown in the calculation of depth-integrated daily production, was 16% larger under light-limiting conditions when E0d was used instead of Ed. Under light-saturating conditions, daily production was only 3% larger. Conversion of underwater irradiance data also plays a role in the ratio of total quanta to total energy (EQ/EW, found to be 4.25), which reflects the spectral shape of the under-ice light field. We use these observations to provide factors for converting irradiance measurements between irradiance detector types and units as a function of surface type and depth under sea ice, towards improving primary production estimates.

Published
2019
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12. Environmental factors influencing the seasonal dynamics of spring algal blooms in and beneath sea ice in western Baffin Bay

Author

Dany Dumont, Patrick Raimbault, Jens K. Ehn, C. J. Mundy, Guislain Bécu, Marcel Babin, P. Coupel, Claudie Marec, Nicole Garcia, Joannie Ferland, Yannis Cuypers, Laurent Oziel, Virginie Galindo, Marie-Hélène Forget, Léo Lacour, Philippe Massicotte, Marie-Noëlle Houssais, Achim Randelhoff, Pascale Bouruet-Aubertot, Simon Lambert-Girard, Anda Vladoiu, Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université du Québec à Rimouski (UQAR), University of Manitoba [Winnipeg], Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Variabilité de l'Océan et de la Glace de mer (VOG), CNES (project #131425), IPEV (project #1164), CSA, Fondation Total, ArcticNet, LEFE and the French Arctic Initiative (Green Edge project), ANR-14-CE01-0017,Green Edge,Productivité biologique dans l'Océan Arctique: réponse passée, présente et future aux fluctuations climatiques, et impacts sur les flux de carbone, le réseau trophique et les communautés humaines locales(2014), Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-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)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), and Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne)

Subjects
0106 biological sciences, Atmospheric Science, Environmental Engineering, 010504 meteorology & atmospheric sciences, Light and mixing, Under-ice bloom, Phytoplankton and sea ice algae, Arctic Ocean, Baffin Bay, Environmental conditions, Oceanography, 01 natural sciences, Algal bloom, Water column, Phytoplankton, Sea ice, 14. Life underwater, lcsh:Environmental sciences, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, lcsh:GE1-350, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Geology, Geotechnical Engineering and Engineering Geology, Snow, Arctic ice pack, Arctic, 13. Climate action, Environmental science, Bloom
Abstract

Arctic sea ice is experiencing a shorter growth season and an earlier ice melt onset. The significance of spring microalgal blooms taking place prior to sea ice breakup is the subject of ongoing scientific debate. During the Green Edge project, unique time-series data were collected during two field campaigns held in spring 2015 and 2016, which documented for the first time the concomitant temporal evolution of the sea ice algal and phytoplankton blooms in and beneath the landfast sea ice in western Baffin Bay. Sea ice algal and phytoplankton blooms were negatively correlated and respectively reached 26 (6) and 152 (182) mg of chlorophyll a per m2 in 2015 (2016). Here, we describe and compare the seasonal evolutions of a wide variety of physical forcings, particularly key components of the atmosphere–snow–ice–ocean system, that influenced microalgal growth during both years. Ice algal growth was observed under low-light conditions before the snow melt period and was much higher in 2015 due to less snowfall. By increasing light availability and water column stratification, the snow melt onset marked the initiation of the phytoplankton bloom and, concomitantly, the termination of the ice algal bloom. This study therefore underlines the major role of snow on the seasonal dynamics of microalgae in western Baffin Bay. The under-ice water column was dominated by Arctic Waters. Just before the sea ice broke up, phytoplankton had consumed most of the nutrients in the surface layer. A subsurface chlorophyll maximum appeared and deepened, favored by spring tide-induced mixing, reaching the best compromise between light and nutrient availability. This deepening evidenced the importance of upper ocean tidal dynamics for shaping vertical development of the under-ice phytoplankton bloom, a major biological event along the western coast of Baffin Bay, which reached similar magnitude to the offshore ice-edge bloom.

Published
2019
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13. A functional regression model for predicting optical depth and estimating attenuation coefficients in sea-ice covers near Resolute Passage, Canada

Author

Shaun Mcdonald, Theodoro Koulis, Karley Campbell, C. J. Mundy, Jens K. Ehn, and Michel Gosselin

Subjects
0106 biological sciences, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Attenuation, Irradiance, Functional data analysis, Snow, 01 natural sciences, Arctic ice pack, Arctic, Climatology, Sea ice, Optical depth, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

The spectral dependence of natural light transmittance on ice algae concentration and snow depth in Arctic sea ice provides the potential to study the changing bottom-ice ecosystem using optical relationships. In this paper, we consider the use of functional data analysis techniques to describe such relationships. Specifically, we created a functional regression model describing spectral optical depth as a function of chlorophyll a concentration, snow depth and ice thickness. Measurements of the aforementioned covariates and surface and transmitted spectral irradiance were collected on landfast first-year sea ice in the High Arctic near Resolute Passage, Canada, during the spring of 2011 and used as model input. The derived model explains 75–84.5% of the variation in the observed spectral optical depth curves. No prior assumptions of snow/sea-ice optical properties are required in the application of this technique, as the model estimates the attenuation coefficients of each covariate using only the measurements mentioned above. The quality and simplicity of the model highlight the potential of functional data analysis to study the Arctic marine ecosystem.

Published
2015
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14. Assessment of light absorption within highly scattering bottom sea ice from under-ice light measurements: Implications for Arctic ice algae primary production

Author

C. J. Mundy and Jens K. Ehn

Subjects
Chlorophyll a, geography, geography.geographical_feature_category, Opacity, Attenuation, Aquatic Science, Spring bloom, Oceanography, Atmospheric sciences, Arctic ice pack, chemistry.chemical_compound, chemistry, Sea ice thickness, Sea ice, Environmental science, Absorption (electromagnetic radiation)
Abstract

Primary production estimates of ice algae within the bottommost layers of the Arctic ice cover are commonly derived using irradiance measurements taken immediately below the solid ice bottom. However, radiation absorbed by ice algae is significantly affected by the high-scattering sea ice environment they are embedded within because scattering increases the pathlength traveled by photons and therefore the probability of photon encounters with algal cells. Failing to account for this enhanced absorption may considerably affect estimates of the timing and magnitude of ice algal production. To demonstrate the effect of scattering and attenuation, multipliers for absorption amplification (Φ) and layer average opacity (χ) were derived from observations of chlorophyll a concentration and the vertical attenuation coefficient over the bottom 2.5 cm of landfast sea ice. Φ reached values over 19 at low chlorophyll a, but became < 2 at high biomass levels, whereas χ became larger as biomass levels increased. Using Φ to construct an apparent photosynthesis vs. irradiance relationship showed that light limitation is greatly reduced relative to the case where scattering is not considered. This highlights an important interaction not previously noted for ice algal production in their high-scattering environment. Knowledge of this absorption amplification can help explain ice algal phenology during the spring bloom and will improve ice algal production estimates and model parameterizations.

Published
2013
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15. Riverine export and the effects of circulation on dissolved organic carbon in the Hudson Bay system, Canada

Author

C. J. Mundy a, Michel Gosselin, Michel Starr, and Christine Michelc

Subjects
Total organic carbon, geography, geography.geographical_feature_category, Terrigenous sediment, Brine rejection, Aquatic Science, Oceanography, Algal bloom, Dissolved organic carbon, Sea ice, Environmental science, Water quality, Bay
Abstract

The distribution of dissolved organic carbon (DOC) in Hudson Bay (HB), Foxe Basin (FB), and Hudson Strait (HS) was examined during 01-14 August 2003. The HB system displayed relatively high DOC concentrations with medians of 109, 90, and 100 mmol L−1 for measurements made in HB, FB, and HS, respectively. Waters were significantly modified as they circulated through the HB system. An influence of marine-derived DOC was inferred for waters entering the system from northern HS and FB. The presence of a cold-water layer and elevated DOC concentrations observed in HB along the western coast and at depth was explained through either brine rejection and export of surface DOC to depth during sea ice formation or the decomposition of a settling algal bloom. As waters circulated in HB, an input of terrigenous DOC was the dominant modifying factor. In particular, DOC-laden rivers in southern HB increased the DOC concentration and then displayed a conservative behavior as water exited the bay along the southern coast of HS. Additionally, the late stages of ice melt observed during this study showed a significant dilution effect on surface DOC concentrations within eastern HB. Input and export of riverine DOC in the HB system was estimated at ~5.5 Tg C yr−1, which is approximately 23% of the annual DOC input from rivers draining directly into the central Arctic Ocean and therefore represents an important contribution of terrigenous carbon to northern seas.

Published
2009
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16. On the relationship between spatial patterns of sea‐ice type and the mechanisms which create and maintain the North Water (NOW) polynya

Author

C J Mundy and David G. Barber

Subjects
Atmospheric Science, geography, geography.geographical_feature_category, Geographic information system, Spatial structure, business.industry, Context (language use), Oceanography, Climatology, Latent heat, Spring (hydrology), Sea ice, Spatial ecology, business, Bay, Geology
Abstract

Polynyas represent polar oceanic areas with anomalous low sea‐ice concentrations. The North Water (NOW) Polynya refers to a region at the northern end of Baffin Bay which encompasses three separate polynyas. This paper examines the spatial patterns of sea‐ice cover within the NOW region during the winter, spring and fall of 1998 in the context of polynya formation and maintenance mechanisms. To accomplish this a sea‐ice classification scheme for RADARSAT‐1 ScanSAR imagery, obtained between 21 January and 7 December 1998, was developed and implemented within a Geographic Information System (GIS). The results identify a clear and consistent spatial structure of sea‐ice cover throughout the winter, spring and fall of 1998. Temporally, the polynya opened southward along the Canadian coast and westward away from the Greenland coast. Comparison with parallel oceanographic, atmospheric and ice motion studies suggested that the polynya was primarily controlled by a latent heat mechanism with the exceptio...

Published
2001
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17. Coastal conduit in southwestern Hudson Bay (Canada) in summer: Rapid transit of freshwater and significant loss of colored dissolved organic matter

Author

François J. Saucier, C. J. Mundy, Simon Senneville, Robie W. Macdonald, Zou Zou A. Kuzyk, David G. Barber, Gary A. Stern, and Mats A. Granskog

Subjects
Atmospheric Science, Mixed layer, Soil Science, Aquatic Science, Oceanography, Sink (geography), Geochemistry and Petrology, Dissolved organic carbon, Earth and Planetary Sciences (miscellaneous), Sea ice, Earth-Surface Processes, Water Science and Technology, Shore, Hydrology, geography, geography.geographical_feature_category, Ecology, Paleontology, Forestry, Salinity, Colored dissolved organic matter, Geophysics, Space and Planetary Science, Environmental science, Bay
Abstract

[1] Distributions of freshwater (sea-ice melt and runoff) were investigated along inshore-offshore sections in southwestern Hudson Bay for fall conditions. Conductivity- temperature-density profiles and bottle samples collected for salinity, oxygen isotope (δ 18 O), and colored dissolved organic matter (CDOM) analyses were used to discriminate between contributions of river water (RW) and sea-ice melt (SIM). Stations had a fresh summer surface mixed layer 5-25 m thick overlying a cold subsurface layer indicative of the previous winter's polar mixed layer (PML). The fraction of RW decreased strongly with distance from shore, while the opposite was true for SIM. The majority of RW was constrained in a coastal domain within 100-150 km from shore, which, because of high alongshore velocities, accounts for the majority of freshwater and volume transports. On the basis of freshwater inventories and composition, brine and RW accumulate in the PML over winter because of ice formation and downward mixing. The summer surface circulation results in an annual net export of SIM from the region. Residence times for freshwater components in the southwestern sector of the bay, based on currents derived from a 3-D ocean model for Hudson Bay, are about 1-10 months, implying rapid transit of freshwater. Despite the short residence time for RW (1- 3 months), CDOM is significantly photobleached and provides an unreliable tracer for RW. Photobleaching represents an important sink for dissolved organic carbon entering from rivers and could, in part, explain why Hudson Bay is only a minor sink for atmospheric CO 2 in the open water season.

Published
2009
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