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| Randelhoff, Achim; Ozierm, Laurent; Massicotte, Philippe; Becu, Guislain; Gali, Marti; Lacour, Leo; Dumont, Dany; Vladoiu, Anda; Marec, Claudie; Bruyant, Flavienne; Houssais, Marie-noelle; Tremblay, Jean-eric; Deslongchamps, Gabriele; Babin, Marcel. |
| During summer, phytoplankton can bloom in the Arctic Ocean, both in open water and under ice, often strongly linked to the retreating ice edge. There, the surface ocean responds to steep lateral gradients in ice melt, mixing, and light input, shaping the Arctic ecosystem in unique ways not found in other regions of the world ocean. In 2016, we sampled a high-resolution grid of 135 hydrographic stations in Baffin Bay as part of the Green Edge project to study the ice-edge bloom, including turbulent vertical mixing, the under-ice light field, concentrations of inorganic nutrients, and phytoplankton biomass. We found pronounced differences between an Atlantic sector dominated by the warm West Greenland Current and an Arctic sector with surface waters... |
| Tipo: Text |
Palavras-chave: Arctic; Phytoplankton; Ice edge; Spring bloom; Light; Turbulence. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00504/61530/65391.pdf |
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| Zippel, Seth F.; Maksym, Ted; Scully, Malcolm; Sutherland, Peter; Dumont, Dany. |
| Observations of waves, winds, turbulence, and the geometry and circulation of windrows were made in a shallow bay in the winter of 2018 outside of Rimouski, Québec. Water velocities measured from a forward-looking pulse-coherent ADCP mounted on a small zodiac show spanwise (cross-windrow) convergence, streamwise (downwind) velocity enhancement, and downwelling in the windrows, consistent with the view that windrows are the result of counter-rotating pairs of wind-aligned vortices. The spacing of windrows, measured with acoustic backscatter and with surface imagery, was measured to be approximately twice the water depth, which suggests an aspect ratio of 1. The magnitude and vertical distribution of turbulence measured from the ADCP are consistent with a... |
| Tipo: Text |
Palavras-chave: Ocean; Atmosphere-ocean interaction; Boundary layer; Langmuir circulation; In situ oceanic observations; Surface observations. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00593/70552/68722.pdf |
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| Massicotte, Philippe; Amiraux, Rémi; Amyot, Marie-pier; Archambault, Philippe; Ardyna, Mathieu; Arnaud, Laurent; Artigue, Lise; Aubry, Cyril; Ayotte, Pierre; Bécu, Guislain; Bélanger, Simon; Benner, Ronald; Bittig, Henry C; Bricaud, Annick; Brossier, Eric; Bruyant, Flavienne; Chauvaud, Laurent; Christiansen-stowe, Debra; Claustre, Hervé; Cornet-barthaux, Véronique; Coupel, Pierre; Cox, Christine; Delaforge, Aurélie; Dezutter, Thibault; Dimier, Céline; Dominé, Florent; Dufour, Francis; Dufresne, Christiane; Dumont, Dany; Ehn, Jens; Else, Brent; Ferland, Joannie; Forget, Marie-hélène; Fortier, Louis; Gali, Marti; Galindo, Virginie; Gallinari, Morgane; Garcia, Nicole; Gerikas-ribeiro, Catherine; Gourdal, Margaux; Gourvil, Priscilla; Goyens, Clemence; Grondin, Pierre-luc; Guillot, Pascal; Guilmette, Caroline; Houssais, Marie-noëlle; Joux, Fabien; Lacour, Léo; Lacour, Thomas; Lafond, Augustin; Lagunas, José; Lalande, Catherine; Laliberté, Julien; Lambert-girard, Simon; Larivière, Jade; Lavaud, Johann; Lebaron, Anita; Leblanc, Karine; Le Gall, Florence; Legras, Justine; Lemire, Mélanie; Levasseur, Maurice; Leymarie, Edouard; Leynaert, Aude; Lopes Dos Santos, Adriana; Lourenço, Antonio; Mah, David; Marec, Claudie; Marie, Dominique; Martin, Nicolas; Marty, Constance; Marty, Sabine; Massé, Guillaume; Matsuoka, Atsushi; Matthes, Lisa; Moriceau, Brivaela; Muller, Pierre-emmanuel; Mundy, Christopher-john; Neukermans, Griet; Oziel, Laurent; Panagiotopoulos, Christos; Pangazi, Jean-jacques; Picard, Ghislain; Picheral, Marc; Pinczon Du Sel, France; Pogorzelec, Nicole; Probert, Ian; Queguiner, Bernard; Raimbault, Patrick; Ras, Joséphine; Rehm, Eric; Reimer, Erin; Rontani, Jean-françois; Rysgaard, Soren; Saint-béat, Blanche; Sampei, Makoto; Sansoulet, Julie; Schmidt, Sabine; Sempere, Richard; Sevigny, Caroline; Shen, Yuan; Tragin, Margot; Tremblay, Jean-eric; Vaulot, Daniel; Verin, Gauthier; Vivier, Frédéric; Vladoiu, Anda; Whitehead, Jeremy; Babin, Marcel. |
| The Green Edge initiative was developed to investigate the processes controlling the primary productivity and the 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 (67.4797N, 63.7895W). 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 temperature, salinity, radiance, irradiance, nutrient concentrations, chlorophyll-a concentration,... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00598/71000/69266.pdf |
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| Olivier, Frederic; Gaillard, Blandine; Thebault, Julien; Meziane, Tarik; Tremblay, Rejean; Dumont, Dany; Belanger, Simon; Gosselin, Michel; Jolivet, Aurelie; Chauvaud, Laurent; Martel, Andre L.; Rysgaard, Soren; Olivier, Anne-helene; Pettre, Julien; Mars, Jerome; Gerber, Silvain; Archambault, Philippe. |
| Climate changes in the Arctic may weaken the currently tight pelagic-benthic coupling. In response to decreasing sea ice cover, arctic marine systems are expected to shift from a 'sea-ice algae-benthos' to a 'phytoplankton-zooplankton' dominance. We used mollusc shells as bioarchives and fatty acid trophic markers to estimate the effects of the reduction of sea ice cover on the food exported to the seafloor. Bathyal bivalve Astarte moerchi living at 600m depth in northern Baffin Bay reveals a clear shift in growth variations and Ba/Ca ratios since the late 1970s, which we relate to a change in food availability. Tissue fatty acid compositions show that this species feeds mainly on microalgae exported from the euphotic zone to the seabed. We, therefore,... |
| Tipo: Text |
Palavras-chave: Arctic; Climate change; Sclerochronology; Pelagic-benthic coupling; Match; Mismatch hypothesis; Bivalve growth. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00686/79854/82695.pdf |
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| Sutherland, Peter; Dumont, Dany. |
| Ocean surface wave radiation stress represents the flux of momentum due to the waves. When waves are dissipated or reflected by sea ice, that momentum is absorbed or reflected, resulting in a horizontal forcing which frequently compresses the ice. In this work, wave radiation stress is used to estimate the compressive force applied by waves to the marginal ice zone (MIZ). It is balanced by an ice internal compressive stress based on Mohr-Coulomb granular materials theory. The ice internal stress can be related to ice thickness, allowing this force balance to be used as a model for the estimation of MIZ ice thickness. The model was validated and tested using data collected during two field campaigns in the St. Lawrence Estuary in 2016 and 2017. Modelled ice... |
| Tipo: Text |
Palavras-chave: Sea ice; Momentum; Waves; Oceanic; Ice thickness. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/55994/57486.pdf |
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| Didier, David; Bernatchez, Pascal; Augereau, Emmanuel; Caulet, Charles; Dumont, Dany; Bismuth, Eliott; Cormier, Louis; Floc'H, France; Delacourt, Christophe. |
| Increasingly used shore-based video stations enable a high spatiotemporal frequency analysis of shoreline migration. Shoreline detection techniques combined with hydrodynamic conditions enable the creation of digital elevation models (DEMs). However, shoreline elevations are often estimated based on nearshore process empirical equations leading to uncertainties in video-based topography. To achieve high DEM correspondence between both techniques, we assessed video-derived DEMs against LiDAR surveys during low energy conditions. A newly installed video system on a tidal flat in the St. Lawrence Estuary, Atlantic Canada, served as a test case. Shorelines were automatically detected from time-averaged (TIMEX) images using color ratios in low energy conditions... |
| Tipo: Text |
Palavras-chave: Video monitoring; Shoreline detection; Beach morphology; Mobile terrestrial LiDAR; Erosion; Atlantic Canada. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75022/75656.pdf |
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| Boutin, Guillaume; Ardhuin, Fabrice; Dumont, Dany; Sevigny, Caroline; Girard Ardhuin, Fanny; Accensi, Mickael. |
| Wind waves may play an important role in the evolution of sea ice. That role is largely determined by how fast the ice layer dissipates the wave energy. The transition from a continuous layer of ice to a series of broken floes is expected to have a strong impact on the several attenuation processes. Here we explore the possible effects of basal friction, scattering, and dissipation within the ice layer. The ice is treated as a single layer that can be fractured in many floes. Dissipation associated with ice flexure is evaluated using an anelastic linear dissipation and a cubic inelastic viscous dissipation. Tests aiming to reproduce a Marginal Ice Zone are used to discuss the effects of each process separately. Attenuation is exponential for friction and... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00454/56591/58274.pdf |
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