Manioc : Portail | resultats 61 - 80 pour la recherche: Oceanography

Rapport annuel 1999

Résumé : Président de l'Ifremer depuis mars 2000, je suis amené à commenter le bilan de l'activité de notre organisme au cours de 1999, et a traduire l'action de mon prédécesseur, Pierre David. La plupart des réalisations, des résultats ou des réorganisations prennent leur source dans des choix des années précédentes, et donc dans sa stratégie a l'échelle de son mandat. Les priorités affichées par Pierre David concernaient l'environnement du littoral, la gestion des ressources halieutiques et le rôle d'agence de moyens a la mer. En ce qui concerne le rôle d'agence de moyens. le nombre de jours de mer de la flotte hauturière a baissé en 1999 de 10% par rapport a 1998, mais cela résulte d'un choix d'investissement et de développement technologique préparant le futur: le Nadir a largement été employé au test de la nouvelle sismique multitraces, le plus performant des outils de recherche académique en Europe, tandis que Le Suroît a été désarmé pour sa refonte. Les océanographes disposeront ainsi d'un navire de taille moyenne performant et bien équipé pour les dix prochaines années. II faut aussi noter l'entrée en fonctionnement du Victor 6000, le nouvel engin téléopéré. L'étude des ressources halieutiques s'oriente plus nettement vers celle de I'. écologie halieutique, notamment avec l'ouverture du chantier du golfe de Gascogne dans le cadre du Pnec (programme national de l'environnement côtier), ainsi qu'avec la poursuite des développements d'outils de pêche sélective. D'autre part, on notera la contribution de l'Ifremer au renforcement de la concertation internationale sur les pêches méditerranéennes. L'aquaculture poursuit son recentrage, avec un moindre effort en zootechnie, mais des développements "amont" sur les questions des pathologies, de la sélection génétique et du respect des contraintes d'environnement. Le succès économique de la perliculture à Tahiti et de la crevetticulture en Nouvelle Calédonie se confirme. [OCR NON CONTRÔLE]

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1999/rapport-5299.PDF
http://archimer.ifremer.fr/doc/00000/5299/

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Superfast Spreading Rate Crust 4 Integrated Ocean Drilling Program Expedition 335 Scientific Prospectus
Auteur(s) : Teagle, D. Ildefonse, Benoit Blum, P.
Auteurs secondaires : National Oceanography Centre, Southampton ; Université du Québec Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Texas A&M University [College Station]

Éditeur(s) : HAL CCSD IODP
Résumé : Integrated Ocean Drilling Program (IODP) Expedition 335 (14 April–4 June 2011) will be the fourth ocean cruise of the "Superfast" campaign to drill a deep hole into intact oceanic basement and will return to Ocean Drilling Program (ODP) Hole 1256D to deepen this scientific reference penetration a significant distance into cumulate gabbros. Cores and data recovered during the Superfast 4 expedition will provide hitherto unavailable observations that will test models of the accretion and evolution of the oceanic crust. Site 1256 was specifically located on oceanic crust that formed at a superfast spreading rate (>200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks.
https://hal.archives-ouvertes.fr/hal-00564953

hal-00564953
https://hal.archives-ouvertes.fr/hal-00564953
DOI : 10.2204/iodp.sp.335.2010

200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks."> 200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks."> 200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks."> 200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks."> | 200 mm/y) to exploit the observed relationship between spreading rate and depth to axial low velocity zones, thought to be magma chambers, seismically imaged at active mid-ocean ridges. This was a deliberate strategy to reduce the drilling distance to gabbroic rocks because thick sequences of lavas and dikes have proved difficult to penetrate in past. ODP Leg 206 (2002) initiated operations at Site 1256, including the installation in Hole 1256D of a reentry cone with 16 inch casing inserted through the 250 m thick sedimentary cover and cemented into basement to facilitate deep drilling. The hole was then cored ~500 m into basement. IODP Expeditions 309 and 312 (2005) successfully completed the first sampling of an intact section of upper oceanic crust from lavas, through the sheeted dikes, and into the upper gabbros. Hole 1256D now penetrates >1500 meters below seafloor (mbsf) and >1250 m subbasement and currently resides in the dike–gabbro transition zone. The first gabbroic rocks were encountered at 1407 mbsf. Below this lies a ~100 m complex zone of fractionated gabbros intruded into contact metamorphosed dikes. Although previous cruises achieved the benchmark objective of reaching gabbro in intact ocean crust, critical scientific questions remain. These include the following: 1. Does the lower crust form by the recrystallization and subsidence of a high-level magma chamber (gabbro glacier), crustal accretion by intrusion of sills throughout the lower crust, or some other mechanism? 2. Is the plutonic crust cooled by conduction or hydrothermal circulation? 3. What is the geological nature of Layer 3 and the Layer 2/3 boundary at Site 1256? 4. What is the magnetic contribution of the lower crust to marine magnetic anomalies? Hole 1256D is poised at a depth where samples that should conclusively address these questions can be obtained, possibly with only a few hundred meters of drilling. Importantly, as of the end of Expedition 312, the hole was clear of debris and open to its full depth. Increased rates of penetration (1.2 m/h) and enhanced core recovery (>35%) in the gabbros indicate that this return to Hole 1256D could deepen the hole >300 m into plutonic rocks, past the transition from dikes to gabbro, and into a region of solely cumulate gabbroic rocks.">Plus

Biologie larvaire et développement des thons. Des larves et des zones de ponte à l'élevage en enclos marins et à l'alevinage des océans
Auteur(s) : Le Gall, Jean-yves

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Life history, larval dispersal, and connectivity in coral reef fishamong the Scattered Islands of the Mozambique Channel
Auteur(s) : O’Donnell, J. L. Beldade, Ricardo Mills, C. Williams, Hannah e. Bernardi, Giacomo
Auteurs secondaires : Department of Ecology and Evolutionary Biology ; University of California [Santa Cruz] (UCSC) School of marine and environmental affairs ; University of Washington [Seattle] Centre de recherches insulaires et observatoire de l'environnement (CRIOBE) ; Université de Perpignan Via Domitia (UPVD) - École pratique des hautes études (EPHE) - Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Excellence CORAIL (LabEX CORAIL) ; Institut de Recherche pour le Développement (IRD) - Université des Antilles et de la Guyane (UAG) - École des hautes études en sciences sociales (EHESS) - École pratique des hautes études (EPHE) - Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) - Université de la Réunion (UR) - Université de la Polynésie Française (UPF) - Université de Nouvelle Calédonie - Institut d'écologie et environnement

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The Western Indian Ocean harbors one of theworld’s most diverse marine biota yet is threatened byexploitation with few conservation measures in place.Primary candidates for conservation in the region are theScattered Islands (Iles Eparses), a group of relativelypristine and uninhabited islands in the MozambiqueChannel. However, while optimal conservation strategiesdepend on the degree of population connectivity amongspatially isolated habitats, very few studies have beenconducted in the area. Here, we use highly variablemicrosatellite markers from two damselfishes (Amphiprionakallopisos and Dascyllus trimaculatus) with differing lifehistory traits [pelagic larval duration (PLD), adult habitat]to compare genetic structure and connectivity among theseislands using classic population structure indices as well asBayesian clustering methods. All classical fixation indexesFST, RST, G0ST, and Jost’s D show stronger genetic differentiationamong islands for A. akallopisos compared to D.trimaculatus, consistent with the former species’ shorterPLD and stronger adult site attachment, which may restrictlarval dispersal potential. In agreement with these results,the Bayesian analysis revealed clear genetic differentiationamong the islands in A. akallopisos, separating the southerngroup (Bassas da India and Europa) from the center(Juan de Nova) and northern (Iles Glorieuses) islands, butnot for D. trimaculatus. Local oceanographic patterns suchas eddies that occur along the Mozambique Channel appearto parallel the results reported for A. akallopisos, but suchfeatures seem to have little effect on the genetic differentiationof D. trimaculatus. The contrasting patterns ofgenetic differentiation between species within the samefamily highlight the importance of accounting for diverselife history traits when assessing community-wide connectivity,an increasingly common consideration in conservationplanning.
ISSN: 0722-4028

hal-01561992
https://hal-univ-perp.archives-ouvertes.fr/hal-01561992
DOI : 10.1007/s00338-016-1495-z

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Influence des ondes de Rossby sur le système biogéochimique de l'Océan Atlantique Nord: Utilisation des données satellites couleur de l'eau et d'un modèle couplé physique/biogéochimie
Auteur(s) : Charria, Guillaume

Éditeur(s) : Université Paul Sabatier, Toulouse III
Résumé : The marine phytoplankton in the ocean represents only less than 1% of global biomass. Phytoplankton performs half of all photosynthesis. This autotrophic biomass in ocean is then an essential element in the climate regulation through processes as carbon dioxide absorption during the photosynthesis. Therefore, we need to estimate precisely this biomass as well as the processes which affect it. Using remotely sensed data (altimetry and ocean colour) and a coupled physical/biogeochemical model (MERCATOR-OPA/NPZDDON), Rossby waves and their influence on phytoplankton biomass are specifically studied in the North Atlantic Ocean. Their features and their influences on surface chlorophyll concentrations were analysed. Through the different mechanisms identified, we estimated that these waves can induce local increases from 60% to 150% of the estimated primary production.
Même si l'océan ne représente que moins de 1% de la biomasse liée aux plantes sur la terre, il est responsable de près de la moitié de la photosynthèse nette de la biosphère. Cette biomasse est par conséquent un élément essentiel dans la régulation du climat à travers par exemple le cycle océanique du carbone. Il est donc nécessaire d'estimer correctement cette biomasse ainsi que les processus qui l'affectent. A l'aide de données satellites altimétriques et couleur de l'eau et d'un modèle couplé physique/biogéochimie (MERCATOR-OPA / NPZDDON), les ondes de Rossby et leur influence sur cette biomasse sont spécifiquement étudiées dans l'océan Atlantique Nord. Leurs propriétés et leur influence sur les concentrations en chlorophylle de surface sont analysées. Au travers des mécanismes mis en jeu identifiés, nous estimons que ces ondes peuvent entraîner une augmentation locale comprise entre 60% et 150% de la production primaire estimée.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2005/these-2454.pdf
http://archimer.ifremer.fr/doc/00000/2454/

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Environmental setting of deep-water oysters in the Bay of Biscay
Auteur(s) : Van Rooij, David De Mol, L. Le Guilloux, Erwan Wisshak, M. Huvenne, V. A. I. Moeremans, R. Henriet, Jean-pierre

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : We report the northernmost and deepest known occurrence of deep-water pycnodontine oysters based on two surveys along the French Atlantic continental margin to the La Chapelle continental slope (2006) and the Guilvinec Canyon (2008) The combined use of multibeam bathymetry seismic profiling CTD casts and a remotely operated vehicle (ROV) made it possible to describe the physical habitat and to assess the oceanographic control for the recently described species Neopycnodonte zibrowii These oysters have been observed in vivo in depths from 540 to 846 m colonizing overhanging banks or escarpments protruding from steep canyon flanks Especially in the Bay of Biscay such physical habitats may only be observed within canyons where they are created by both long-term turbiditic and contouritic processes Frequent observations of sand ripples on the seabed indicate the presence of a steady but enhanced bottom current of about 40 cm/s The occurrence of oysters also coincides with the Interface between the Eastern North Atlantic Water and the Mediterranean Outflow Water A combination of this water mass mixing internal tide generation and a strong primary surface productivity may generate an enhanced nutrient flux which is funnelled through the canyon When the ideal environmental conditions are met up to 100 individuals per m(2) may be observed These deep-water oysters require a vertical habitat which is often incompatible with the requirements of other sessile organisms and are only sparsely distributed along the continental margins The discovery of these giant oyster banks illustrates the rich biodiversity of deep-sea canyons and their underestimation as true ecosystem hotspots (C) 2010 Elsevier Ltd All rights reserved
Deep-sea Research Part I-oceanographic Research Papers (0967-0637) (Pergamon-elsevier Science Ltd), 2010-12 , Vol. 57 , N. 12 , P. 1561-1572

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00023/13419/14034.pdf
DOI:10.1016/j.dsr.2010.09.002
http://archimer.ifremer.fr/doc/00023/13419/

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Multiscale Analysis of Wind Velocity, Power Output and Rotation of a Windmill
Auteur(s) : Durán Medina , Olmo Schmitt, François G Calif, Rudy
Auteurs secondaires : Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG) ; Université de Lille, Sciences et Technologies - Université du Littoral Côte d'Opale - Centre National de la Recherche Scientifique (CNRS) Laboratoire de Recherche en Géosciences et Énergies (LaRGE) ; Université des Antilles et de la Guyane (UAG)

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Evaluation of sediment trace metal records as paleoproductivity and paleoxygenation proxies in the upwelling center off Concepcion, Chile (36 degrees S)
Auteur(s) : Munoz, Praxedes Dezileau, Laurent Lange, Carina Cardenas, Lissette Sellanes, Javier Salamanca, Marco A. Maldonado, Antonio
Auteurs secondaires : Universidad Católica del Norte, Coquimbo Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Universidad de Concepción [Chile] Facultad de Ciencias, Universidad de La Serena ; Universidad de La Serena (USERENA)

Éditeur(s) : HAL CCSD Elsevier
Résumé : This study analyzes the records of several trace metals sensitive to redox conditions in continental shelf sediments off Concepcion, Chile (36 degrees S). The continental margin off Concepcion (36 S; 73 W) lies beneath an important upwelling center characterized by high primary production rates and, consequently, high fluxes of organic matter. In spring and summer, this material settles to the seafloor where it decays, producing periods of very low oxygen content in bottom waters (<1 mL L-1). In addition, an oxygen minimum zone develops at similar to 100-400 m water depth, where dissolved oxygen levels are <0.5 mL L-1. This situation changes during strong El Nino events, when dissolved oxygen at the bottom increases drastically (>1 mL L-1).;The goals of this study were to determine the input of trace metals to the sediment and to decipher how this information can be used to reveal variations in primary productivity or bottom oxygenation. Gravity cores collected at two stations - VG06-2 over the mid-shelf station (88 m water depth, upper boundary of the oxygen minimum zone) and VG06-3 over the outer shelf (120 m water depth, within the oxygen minimum zone) - were sampled for high resolution profiles (1 cm) of trace metals, biogenic opal, stable isotopes, and total organic carbon. The results suggest that the variability in the trace metal distribution on the continental shelf off Concepcion is determined by redox conditions and the organic carbon flux to the bottom. Some sections of the sediment cores from the outer shelf showed appreciable authigenic enrichment of U, Cd, and Mo (EF: 5-10, 2-5, and 10-16 respectively) along with heavier values of delta N-15, suggesting periods of suboxic conditions. During these periods, fluxes of organic material to the bottom were higher, as indicated by elevated TOC and opal contents. Alternating periods of higher and lower trace metal contents were not observed mid-shelf as they were on the outer shelf. Rather, the mid-shelf samples showed authigenic enrichment of U, Cd, and Mo (EF: 1-6, 4-5, and 10-20, respectively) throughout the core except in a 10-cm-thick gray layer. In general, authigenic enrichment of U. Mo, and Cd occurred at both sites, coincident with olive green layers in the cores. These layers were associated with periods of elevated primary productivity and suboxic conditions. Such periods did not seem to last as long as the oxygenated periods, which had higher inputs of refractive detrital material, coincident with the occurrence of distinct gray sediment layers.
ISSN: 0079-6611

hal-00682159
https://hal.archives-ouvertes.fr/hal-00682159
DOI : 10.1016/j.pocean.2011.07.010

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Late Quaternary deep-sea sedimentation in the western Black Sea: New insights from recent coring and seismic data in the deep basin
Auteur(s) : Lericolais, Gilles Bourget, Julien Popescu, Irina Jermannaud, Paul Mulder, T. Jorry, Stephan Panin, N.

Éditeur(s) : Elsevier Science Bv
Résumé : The Danube River Basin–Black Sea area represents a unique natural laboratory for studying the interplay between lithosphere and surface as well as source to sink relationships and their impact on global change. This paper addresses some information on the “active sink” of the system; i.e. the Danube deep sea fan and the Black Sea basin. The present study focuses on the distal sedimentary processes and the evolution of sedimentation since the Last Glacial Maximum. This is investigated through recently acquired long piston coring and shallow seismic data recovered at the boundary of influence of the distal part of the Danube turbidite system (to the north-west) and the Turkish margin (to the south). This dataset provides a good record of the recent changes in the sedimentary supply and climato-eustasy in the Black Sea region during the last 25 ka. This study demonstrates that the deep basin deposits bear the record of the Late Quaternary paleoenvironmental changes and that the western Black Sea constitutes an asymmetric subsident basin bordered by a northern passive margin with confined, mid-size, mud-rich turbidite systems mainly controlled by sea-level, and a southern turbidite ramp margin, tectonically active. Highlights ► Oceanographic results from survey carried out in the western Black Sea are presented. ► The Danube fan distal part: the Black Sea main depositional feature is described. ► This study is on the morphology and gravity sedimentation in the Black Sea deep basin. ► Data were collected at the boundary between the Danube fan and the Turkish margin. ► The dataset provide a good record of sedimentary supply and climato-eustatic changes.
Global And Planetary Change (0921-8181) (Elsevier Science Bv), 2013-04 , Vol. 103 , P. 232-247

Droits : 2012 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00095/20637/18272.pdf
DOI:10.1016/j.gloplacha.2012.05.002
http://archimer.ifremer.fr/doc/00095/20637/

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Drilling constraints on lithospheric accretion and evolution at Atlantis Massif, Mid-Atlantic Ridge 30 degrees N
Auteur(s) : Blackman, D. K. Ildefonse, Benoit John, B. E. Ohara, Y. Miller, D. J. Abe, N. Abratis, M. Andal, E. S.
Auteurs secondaires : University of California [San Diego] (UC San Diego) Manteau et Interfaces ; Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) - Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) University of Wyoming (UW) Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI) ; The University of Tokyo Texas A&M University [College Station] Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Friedrich Schiller Universität [Jena, Germany] Philex Mining Corporation

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
Expeditions 304 and 305 of the Integrated Ocean Drilling Program cored and logged a 1.4 km section of the domal core of Atlantis Massif. Postdrilling research results summarized here constrain the structure and lithology of the Central Dome of this oceanic core complex. The dominantly gabbroic sequence recovered contrasts with predrilling predictions; application of the ground truth in subsequent geophysical processing has produced self-consistent models for the Central Dome. The presence of many thin interfingered petrologic units indicates that the intrusions forming the domal core were emplaced over a minimum of 100-220 kyr, and not as a single magma pulse. Isotopic and mineralogical alteration is intense in the upper 100 m but decreases in intensity with depth. Below 800 m, alteration is restricted to narrow zones surrounding faults, veins, igneous contacts, and to an interval of locally intense serpentinization in olivine-rich troctolite. Hydration of the lithosphere occurred over the complete range of temperature conditions from granulite to zeolite facies, but was predominantly in the amphibolite and greenschist range. Deformation of the sequence was remarkably localized, despite paleomagnetic indications that the dome has undergone at least 45 degrees rotation, presumably during unroofing via detachment faulting. Both the deformation pattern and the lithology contrast with what is known from seafloor studies on the adjacent Southern Ridge of the massif. There, the detachment capping the domal core deformed a 100 m thick zone and serpentinized peridotite comprises similar to 70% of recovered samples. We develop a working model of the evolution of Atlantis Massif over the past 2 Myr, outlining several stages that could explain the observed similarities and differences between the Central Dome and the Southern Ridge.
ISSN: 0148-0227

hal-00617528
https://hal.archives-ouvertes.fr/hal-00617528
https://hal.archives-ouvertes.fr/hal-00617528/document
https://hal.archives-ouvertes.fr/hal-00617528/file/2010JB007931.pdf
DOI : 10.1029/2010JB007931

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The Western Adriatic shelf clinoform: energy-limited bottomset
Auteur(s) : Cattaneo, Antonio Trincardi, Fabio Asioli, Alessandra Correggiari, Annamaria

Éditeur(s) : Elsevier
Résumé : Clinoforms on modern shelves and slopes, as well as in ancient rock records, are widely recognized as a fundamental building element of continental margin growth. Regardless of their dominant lithology, clinoforms are composed of three geometric elements: topset, foreset and bottomset. Traditionally, much emphasis in the study of clinoforms was put on the geometry of the topset, viewed as the most energetic portion of a clinoform and studied to discern if aggradation was active rather than erosional truncation, and on the foreset, the area with the highest sediment accumulation rates. Here we focus on the factors forcing clinoforms to taper out and on the inferred mechanisms for bottomset creation. We base our analysis on muddy shelf clinoforms, a particular class of clinoforms that is typical of low-gradient settings and is characterized by a substantial component of shore-parallel sediment transport. This paper is based on a large dataset of CHIRP-sonar profiles, bathymetric and isopach maps of the Late Holocene clinoform on the Adriatic shelf, where integrated stratigraphic studies from sediment cores allow a very high (in some cases century-scale) chronological resolution. Knowledge on the dominant oceanographic regime affecting sediment dispersal and, ultimately, clinoform development, has been recently refined during the EuroSTRATAFORM collaboration. Muddy clinoforms are markedly three-dimensional features that cannot be entirely understood solely on two-dimensional shore normal sections. We suggest that this class of clinoform is advection dominated and that an increase in the energy regime at the toe of the foreset may prevent sediment from reaching beyond the transition to the bottomset region.
Continental Shelf Research (0278-4343) (Elsevier), 2007-02 , Vol. 27 , N. 3-4 , P. 506-525

Droits : 2006 Elsevier Ltd All rights reserved
http://archimer.ifremer.fr/doc/2007/publication-2409.pdf
DOI:10.1016/j.csr.2006.11.013
http://archimer.ifremer.fr/doc/00000/2409/

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The scaling properties of the turbulent wind using Empirical Mode Decomposition and arbitrary order Hilbert Spectral Analysis
Auteur(s) : Calif, Rudy Schmitt, François G Huang, Yongxiang
Auteurs secondaires : Laboratoire de Recherche en Géosciences et Énergies (LaRGE) ; Université des Antilles et de la Guyane (UAG) Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG) ; Université de Lille, Sciences et Technologies - Université du Littoral Côte d'Opale - Centre National de la Recherche Scientifique (CNRS) Michael Hölling, Joachim Peinke, Stefan Ivanell

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A comparison of dissolved and particulate mn and al distributions in the western north-atlantic
Auteur(s) : Yeats, Pa Dalziel, Ja Moran, Sb

Éditeur(s) : Gauthier-Villars
Résumé : The dissolved Mn distribution on an oceanographic section along 50-degrees-W in the western North Atlantic shows decreasing concentrations in the offshore direction in the surface layer and with depth at the deep water stations. Leachable particulate Mn concentrations are low in the open ocean surface waters and elevated at intermediate depths. Dissolved Al concentrations in the surface layer are higher in the open ocean than on the shelf and the vertical distributions are characterized by surface maxima, a subsurface minimum at almost-equal-to 1 000 m and increasing concentrations in the deep waters. Leachable particulate Al concentrations are elevated on the shelf and in open ocean surface waters compared to the intermediate and deep waters. The Deep Western Boundary Current has high levels of dissolved Al and leachable particulate Mn and Al, and low levels of dissolved Mn. The distribution of dissolved Al is controlled primarily by inputs from atmospheric dust and removal onto biogenic particles. Both fluvial and atmospheric inputs affect dissolved Mn levels with removal occurring primarily by oxidation of Mn2+. The Al distribution is characterized by short residence times in shelf and surface waters and relatively constant distribution coefficients. The Mn distribution is characterized by longer surface water residence times, shorter deep water residence times, and more widely varying distribution coefficients than Al. Removal of Al by a surface adsorption mechanism and Mn by slower oxidation of Mn2+ are consistent with these observations. A model of Mn oxidation kinetics accurately predicts the intermediate depth leachable particulate Mn maximum.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1992 , Vol. 15 , N. 6 , P. 609-619

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00101/21186/18803.pdf
http://archimer.ifremer.fr/doc/00101/21186/

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Global marine protected areas do not secure the evolutionary history of tropical corals and fishes
Auteur(s) : Mouillot, D Parravicini, V Bellwood, David R. Leprieur, F Huang, D Cowman, P. F. Albouy, C Hughes, Terence P.
Auteurs secondaires : MARine Biodiversity Exploitation and Conservation (UMR MARBEC) ; Institut de Recherche pour le Développement (IRD) - Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Australian Research Council Centre of Excellence for Coral Reef Studies ; James Cook University (JCU) - School of Marine and Tropical Biology Laboratoire d'Excellence CORAIL (LabEX CORAIL) ; Institut de Recherche pour le Développement (IRD) - Université des Antilles et de la Guyane (UAG) - École des hautes études en sciences sociales (EHESS) - École pratique des hautes études (EPHE) - Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) - Université de la Réunion (UR) - Université de la Polynésie Française (UPF) - Université de Nouvelle Calédonie - Institut d'écologie et environnement Centre de recherches insulaires et observatoire de l'environnement (CRIOBE) ; Université de Perpignan Via Domitia (UPVD) - École pratique des hautes études (EPHE) - Centre National de la Recherche Scientifique (CNRS) Tropical Marine Science Institute Department of Ecology and Evolutionary Biology ; Yale University [New Haven] Departement de Biologie, Chimie et Géographie ; Université du Québec A Rimouski (UQAR) Laboratoire d'Ecologie Alpine (LECA) ; Université Joseph Fourier - Grenoble 1 (UJF) - Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]) - Centre National de la Recherche Scientifique (CNRS)

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The structure of nearshore currents driven by changes in meteo-marine forcings
Auteur(s) : Petitjean, Lise Sous, Damien Rey, Vincent BOUCHETTE, Frederic Sabatier, Francois Meulé, Samuel
Auteurs secondaires : Institut méditerranéen d'océanologie (MIO) ; Institut de Recherche pour le Développement (IRD) - Aix Marseille Université (AMU) - Institut de recherche pour le développement [IRD] : UMR235 - Université de Toulon (UTLN) - Centre National de la Recherche Scientifique (CNRS) Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Centre européen de recherche et d'enseignement de géosciences de l'environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD) - Aix Marseille Université (AMU) - Collège de France (CdF) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS)

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Upper beach reconstruction patternsafter moderate storm events
Auteur(s) : CAMPMAS, Lucie Bouchette, Frederic Liou, Jying Li Brambilla, Elena Meulé, Samuel Sylaios, Georgios Sabatier, F. Certain, R.
Auteurs secondaires : Risques ; Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) - Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) thl ; Université du Québec Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Centre européen de recherche et d'enseignement de géosciences de l'environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD) - Aix Marseille Université (AMU) - Collège de France (CdF) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS) Laboratory of Ecological Engineering & Technology, Department of Environmental Engineering, University of Thrace ; Université du Québec Centre de formation et de recherche sur l'environnement marin (CEFREM) ; Université de Perpignan Via Domitia (UPVD) - Institut national des sciences de l'Univers (INSU - CNRS) - Centre National de la Recherche Scientifique (CNRS)

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Marine resources of the economic zone of New Caledonia
Auteur(s) : Auzende, Jean-marie Grandperrin, René Bouniot, Emmanuel Henin, Christian Lafoy, Yves De Forges, Bertrand Van De Beuque, Sabrina Virly, Sabrina

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Intermittency study of high frequency global solar radiation sequences under a tropical climate
Auteur(s) : Calif, Rudy Schmitt, François G Huang, Yongxiang Soubdhan, Ted
Auteurs secondaires : Laboratoire de Recherche en Géosciences et Énergies (LaRGE) ; Université des Antilles et de la Guyane (UAG) Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG) ; Centre National de la Recherche Scientifique (CNRS) - Université du Littoral Côte d'Opale - Université de Lille, Sciences et Technologies

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Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
We develop and implement a new method to take into account the impact of waves into the 3-D circulation model SYMPHONIE (Marsaleix et al., 2008, 2009a), following the simplified equations of Bennis et al. (2011) which use glm2z-RANS theory (Ardhuin et al., 2008b). These adiabatic equations are completed by additional parameterizations of wave breaking, bottom friction and wave-enhanced vertical mixing, making the forcing valid from the surf zone through to the open ocean. The wave forcing is performed by wave generation and propagation models WAVEWATCH III® (Tolman, 2008, 2009; Ardhuin et al., 2010) and SWAN (Booij et al., 1999). The model is tested and compared with other models for a plane beach test case, previously tested by Haas and Warner (2009) and Uchiyama et al. (2010). A comparison is also made with the laboratory measurements of Haller et al. (2002) of a barred beach with channels. Results fit with previous simulations performed by other models and with available observational data. Finally, a realistic case of energetic waves travelling over a coast of the Gulf of Lion (in the northwest of the Mediterranean Sea) for which currents are available at different depths as well as an accurate bathymetric database of the 0-10 m depth range, is then simulated. A grid nesting approach is used to account for the different forcings acting at different spatial scales. The simulation coupling the effects of waves and currents is successful to reproduce the powerful northward littoral drift in the 0-15 m depth zone. More precisely, two distinct cases are identified: when waves have a normal angle of incidence with the coast, they are responsible for complex circulation cells and rip currents in the surf zone, and when they travel obliquely, they generate a northward littoral drift. These features are more complicated than in the test cases, due to the complex bathymetry and the consideration of wind and non-stationary processes. Wave impacts in the inner shelf are less visible since wind and regional circulation seem to be the predominant forcings. Besides, a discrepancy between model and observations is noted at that scale, possibly linked to an underestimation of the wind stress. Lastly, this three-dimensional method allows a good representation of vertical current profiles and permits to calculate the shear stress associated with wave and current. Future work will focus on the combination with a sediment transport model.
ISSN: 1812-0806

hal-00766548
https://hal.archives-ouvertes.fr/hal-00766548
https://hal.archives-ouvertes.fr/hal-00766548/document
https://hal.archives-ouvertes.fr/hal-00766548/file/os-8-657-2012.pdf
DOI : 10.5194/osd-8-2417-2011

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