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| Chust, Guillem; Allen, J. Icarus; Bopp, Laurent; Schrum, Corinna; Holt, Jason; Tsiaras, Kostas; Zavatarelli, Marco; Chifflet, Marina; Cannaby, Heather; Dadou, Isabelle; Daewel, Ute; Wakelin, Sarah L.; Machu, Eric; Pushpadas, Dhanya; Butenschon, Momme; Artioli, Yuri; Petihakis, Georges; Smith, Chris; Garcon, Veronique; Goubanova, Katerina; Le Vu, Briac; Fach, Bettina A.; Salihoglu, Baris; Clementi, Emanuela; Irigoien, Xabier. |
| Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis,... |
| Tipo: Text |
Palavras-chave: Ecosystem model; Food web; Plankton; Primary production; Sea warming; Trophic amplification. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29966/28481.pdf |
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| Gutknecht, E.; Dadou, Isabelle; Le Vu, B.; Cambon, Gildas; Sudre, J.; Garcon, V.; Machu, Eric; Rixen, T.; Kock, A.; Flohr, A.; Paulmier, A.; Lavik, G.. |
| The Eastern Boundary Upwelling Systems (EBUS) contribute to one fifth of the global catches in the ocean. Often associated with Oxygen Minimum Zones (OMZs), EBUS represent key regions for the oceanic nitrogen (N) cycle. Important bioavailable N loss due to denitrification and anammox processes as well as greenhouse gas emissions (e. g, N2O) occur also in these EBUS. However, their dynamics are currently crudely represented in global models. In the climate change context, improving our capability to properly represent these areas is crucial due to anticipated changes in the winds, productivity, and oxygen content. We developed a biogeochemical model (BioEBUS) taking into account the main processes linked with EBUS and associated OMZs. We implemented this... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26314/24376.pdf |
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| Huret, Martin; Dadou, Isabelle; Dumas, Franck; Lazure, Pascal; Garcon, Véronique. |
| A coupled three-dimensional physical-biogeochemical model was developed in order to simulate the ecological functioning of the Rio de la Plata estuary and plume. The biogeochemical model reproduces the nitrogen cycle between five compartments: dissolved inorganic nitrogen, phytoplankton, zooplankton, detritus and dissolved organic nitrogen. The coupling is tested in seasonal climatological configurations and for the particular year 1999. The circulation is forced with Parana and Uruguay rivers discharges, NCEP wind and tide. The biogeochemical model includes loads of inorganic and organic nitrogen from both rivers. The model reproduces the correct tidal amplitudes in the estuary, as well as the most outstanding features of the observed horizontal and... |
| Tipo: Text |
Palavras-chave: Rio de la Plata; SeaWiFS; Primary production; Chlorophyll; River plumes; Biogeochemical modelling; Physical. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-334.pdf |
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| Assene, Fernand; Morel, Yves; Delpech, Audrey; Aguedjou, Micael; Jouanno, Julien; Cravatte, Sophie; Marin, Frederic; Ménesguen, Claire; Chaigneau, Alexis; Dadou, Isabelle; Alory, Gael; Holmes, Ryan; Bourlès, Bernard; Koch-larrouy, Ariane. |
| In this paper, we analyse the results from a numerical model at high resolution. We focus on the formation and maintenance of subsurface equatorial currents in the Gulf of Guinea and we base our analysis on the evolution of potential vorticity (PV). We highlight the link between submesoscale processes (involving mixing, friction and filamentation), mesoscale vortices and the mean currents in the area. In the simulation, eastward currents, the South and North Equatorial Undercurrents (SEUC and NEUC respectively) and the Guinea Undercurrent (GUC), are shown to be linked to the westward currents located equatorward. We show that east of 20∘ W, both westward and eastward currents are associated with the spreading of PV tongues by mesoscale vortices. The... |
| Tipo: Text |
Palavras-chave: Equatorial atlantic; NEUC (North Equatorial Undercurrents); SEUC (South Equatorial Undercurrents); Vortices; Mixing; Friction. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00645/75697/76601.pdf |
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| Montes, Ivonne; Dewitte, Boris; Gutknecht, Elodie; Paulmier, Aurelien; Dadou, Isabelle; Oschlies, Andreas; Garcon, Veronique. |
| The connection between the equatorial mean circulation and the oxygen minimum zone (OMZ) in the Eastern Tropical Pacific is investigated through sensitivity experiments with a high-resolution coupled physical-biogeochemical model. A validation against in situ observations indicates a realistic simulation of the vertical and horizontal oxygen distribution by the model. Two sets of climatological open-boundary conditions for the physical variables, which differ slightly with respect to the intensity and vertical structure of the Equatorial Current System, are shown to lead to contrasting characteristics of the simulated OMZ dynamics. From a Lagrangian perspective, the mean differences near the coast originate to a large extent from the different transport of... |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00688/79998/82951.pdf |
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| Gutknecht, E.; Dadou, Isabelle; Marchesiello, P.; Cambon, Gildas; Le Vu, B.; Sudre, J.; Garcon, V.; Machu, Eric; Rixen, T.; Kock, A.; Flohr, A.; Paulmier, A.; Lavik, G.. |
| Eastern boundary upwelling systems (EBUS) are regions of high primary production often associated with oxygen minimum zones (OMZs). They represent key regions for the oceanic nitrogen (N) cycle. By exporting organic matter (OM) and nutrients produced in the coastal region to the open ocean, EBUS can play an important role in sustaining primary production in subtropical gyres. However, losses of fixed inorganic N through denitrification and anammox processes take place in oxygen depleted environments such as EBUS, and can potentially mitigate the role of these regions as a source of N to the open ocean. EBUS can also represent a considerable source of nitrous oxide (N2O) to the atmosphere, affecting the atmospheric budget of N2O. In this paper a 3-D coupled... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26316/24373.pdf |
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| Gutknecht, Elodie; Dadou, Isabelle; Charria, Guillaume; Cipollini, Paolo; Garcon, Veronique. |
| The present study focuses on the spatial and temporal variability of interactions between physics and biogeochemistry during the Rossby wave passage in the South Atlantic Ocean. The Rossby wave signature in sea level anomalies (SLA) and surface chlorophyll a concentration anomalies (CHLA) is analyzed using remotely sensed data from 1997 to 2006. Wavelengths between 400 and 1100 km, with westward propagating speeds up to 7.5 cm.s−1, are observed. Using a theoretical model, three processes (meridional advection of surface chlorophyll a concentrations, uplifting of subsurface chlorophyll a maximum, and upwelling of nutrients) are likely to explain the chlorophyll a Rossby wave signature. A statistical assumption allows quantifying the relative importance of... |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00026/13723/10832.pdf |
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