![]() | SobekCM METS Editor Users Guide Auteur(s) : Sullivan, Mark V. Taylor, Laurie N. Éditeur(s) : University of Florida Libraries University of Florida Libraries ( Gainesville, FL ) Droits : [cc by-sa] This item is licensed with the Creative Commons Attribution Share Alike License. This license lets others remix, tweak, and build upon this work even for commercial reasons, as long as they credit the author and license their new creations under the identical terms. http://ufdc.ufl.edu/UF00103089/00003 | Partager |
![]() | What we are trying to do anyway: Musing on the joy in struggle, diasporic literary theories, and black feminism Auteur(s) : Spencer, Suzette A. Éditeur(s) : Caribbean Studies Association Caribbean Studies Association Résumé : Item was listed as being created by Barbara Christian. On 10/6/2011, this was corrected to list Suzette A. Spencer as the creator from an inquiry to correct the metadata. North America -- Caribbean Caribbean | Partager |
![]() | Rights and Permissions Statements in SobekCM at UF Auteur(s) : Taylor, Laurie N. Yellapantula, Suchitra Dinsmore, Chelsea Éditeur(s) : George A. Smathers Libraries, University of Florida George A. Smathers Libraries, University of Florida ( Gainesville, FL ) Résumé : Information on the Rights and Permissions statements including the per item assignment of rights with the drop-downs for UF specific rights and Creative Commons in addition to options with the default metadata sets and user defined rights. Droits : [cc0] The author dedicated the work to the Commons by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law. http://ufdc.ufl.edu/AA00017119/00030 | Partager |
![]() | Accrétion océanique et déformation dans la partie méridionale du bassin Nord-Fidjien: résultats préliminaires de la campagne océanographique SEAPSO III du N.O. Jean-Charcot (décembre 1985) Auteur(s) : Auzende, Jean-marie Eissen, Jean-philippe Caprais, Marie-paule Gente, Pascal Gueneley, S Harmegnies, Francois Lagabrielle, Yves Lapouille, A Éditeur(s) : Gauthier-villars Résumé : Seismic, Seabeam, magnetic and gravimetrie surveys in the southern part of the N-Fiji basin were conducted during the SEAPSO LEG III Cruise. The active spreading axis was recognized between 17°30'S and 21°S. It consists of a continuous N-S Ridge cross-cut by transverse directions oriented N25 and N45. North of 17°30'S, the spreading System is more complex due to the existence of a possible triple junction located around 15° S. The eastern part of the N-Fiji basin, west of Viti Levu is mostly characterized by alternating highs and deeps (<4,000 m). This area must be regarded no more as a spreading center, but as complex boundary suffering transverse tectonics. La mission SEAPSO III a permis de localiser une zone d'accrétion active, d'orientation méridienne et pratiquement continue entre 17°30'S et 21° S. Des accidents transverses, qui encadrent ou recoupent cette dorsale, s'orientent autour de deux directions principales N25 et N45. Au Nord de 17 30'S le système d'accrétion, beaucoup plus complexe, annonce la triple jonction reconnue aux alentours de 15" S. La partie orientale du bassin Nord-Fidjien (à l'Ouest de l'île de Viti Levu) est caractérisée par l'alternance de zones hautes et de dépressions dont certaines dépassent 4000 m de profondeur. Il s'agit d'une zone complexe de déformations liées à des accidents cisaillants transverses. Comptes Rendus de l'Academie des Sciences Serie II (1251-8069) (Gauthier-villars), 1986-06 , Vol. 303 , N. 1 , P. 93-98 Droits : Académie des Sciences http://archimer.ifremer.fr/doc/00184/29492/27835.pdf http://archimer.ifremer.fr/doc/00184/29492/ | Partager |
![]() | Bonamia-ostreae induced mortalities in one-year old European flat oysters Ostrea edulis: experimental infection by cohabitation challenge Auteur(s) : Lallias, Delphine Arzul, Isabelle Heurtebise, Serge Ferrand, Sylvie Chollet, Bruno Robert, Maeva Beaumont, Andrew Boudry, Pierre Éditeur(s) : Physiomar 08 Physilogical aspects of reproduction, nutrition and growth "Marine molluscs in a changing environment" Résumé : Bonamiosis is a parasitic disease (causative agent: Bonamia ostreae) affecting the European flat oyster Ostrea edulis, responsible for a drastic decline in the aquaculture production of this oyster species. Therefore a selective breeding program for resistance to bonamiosis has been undertaken since 1985 bu Ifremer, leading to the production of several selected oyster families. In the present study, a 6-month cohabitation challenge experiment was performed in order to transmit the disease from wild oysters (injected with the parasite) to two tested families of oysters originating from the selective breeding program. Mortalities were checked daily, and ventricular heart smears were performed on dying or moribund oysters to detect the level of infection to B. ostreae. The first infections occurred after 4 months of challenge in the tested oysters (Family 1 and Family 2). The cumulative mortalities after 5 monts were 58% for the wil oysters, 9% for Family 1 (20-month old at the beginning of the experiment) and 20% for Family 2 (8-month, old). The parasite could be detected in 66.8% of the dying wild oysters, 67.5% of the dying oysters of Family 1, 89% of the dying oysters of Family 2 and only 11% of the surviving oysters of Family 2. The mortality was significantly higher in Family 2 thant in Family 1 (x2= 20.87, p<0.001, d.f.) as well as the level of infection by the parasite found in heart smear (x2=24.34, p<0.001, 4 d.f.). This result demonstrates that prespawning oysters as yong as 1 year-old can become infected with the parasite and die from bonamiosis. This result is inconsistent with the commonly accepted critical age of 2 years-old for the disease development. The most probable cause of the dscrepancy in the development of bonamiosis between the 2 tested families is a difference in genetic background. Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/2008/acte-4535.pdf http://archimer.ifremer.fr/doc/00000/4535/ | Partager |
![]() | Effect of an herbivorous diet on energy balance of Litopenaeus vannamei at selected ontogenetic stages Auteur(s) : Maldonado, Carlos Cuzon, Gerard Guzman, Emilio Brito, Roberto Soto, Luis Arena, Leticia Gaxiola, Gabriela Éditeur(s) : Elsevier Résumé : Herbivorous (20% vegetable protein, 40% carbohydrate) and carnivorous diets (40% marine animal protein, 20% carbohydrate) were experimentally tested to assess their effect on the energy balance and energetic substrates utilized by postlarvae (PL's /15 days) and juvenile shrimp (3-6 g) of Litopenaeus vannamei. Postlarval stage 60 (PL60, early juveniles) shrimps fed HeD and CaD diets, then late juveniles (3-6 g) acclimated to the same diets were tested for their respective energy partitioning potential. No significant differences (p>0.05) on growth were obtained in early juveniles (mean final wet weight of 0.19 g). However in late juvenile stages a significant difference (p<0.05) in growth rate was observed. In terms of energy partitioning, both early and late juveniles seem to spend more energy in respiratory metabolism than in the elimination of excretion products. A change in feed composition based on quality protein sources induced some modifications on shrimp's activity measured by heat increment. Shrimps fed with an herbivorous diet showed a higher heat increment. Interestingly, the early stages of L vannamei display a remarkable capacity to assimilate a plant protein-based and a high carbohydrate level diet. Such capacity with a stimulation of genes would lead to a good adaptation of juveniles receiving all-plant diets to sustain growth performances up to a marketable size. The implications of these findings for the shrimp farming feeding costs are briefly discussed. (C) 2009 Elsevier B.V. All rights reserved. Aquaculture (0044-8486) (Elsevier), 2009-11 , Vol. 296 , N. 1-2 , P. 123-128 Droits : 2009 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/2009/publication-7402.pdf DOI:10.1016/j.aquaculture.2009.08.007 http://archimer.ifremer.fr/doc/00000/7402/ | Partager |
![]() | Variabilité des manifestations hydrothermales actuelles le long d'une dorsale ultra rapide. Dorsale Est Pacifique entre 17° et 19° S (campagne NAUDUR). Auteur(s) : Fouquet, Yves Auzende, Jean-marie Ballu, V Batiza, R Bideau, Daniel Cormier, Mh Geistdoerfer, P Lagabrielle, Yves Éditeur(s) : Gauthier-villars Résumé : 69 new hydrothermal sites were discovered during the Naudur diving cruise. Dives were conducted between 17 degrees 5 and 18 degrees 40'5 on four segments showing marked contrast in morphology, volcanic, tectonic and hydrothermal activity. At 17 degrees 10'5, 17 degrees 25'5 and 18 degrees 37'5 the ridge has a dome shaped cross-section and is dominated by very active volcanic activity. Early widespread low temperature (<50 degrees C) diffuse hydrothermal discharge is followed by focused high temperature black smokers. At 18 degrees 15'S tectonic activity is dominant, no recent lava was observed, and only two of the 20 hydrothermal sites are active. At 18 degrees 32'5 recent lava representing a new volcanic episode partly covers the bottom of the graben. Deep hydrothermal convection is reactivated with new black smokers along the graben wall. Also, there is low temperature shimmering water from cooling lava flows. These three segments can be considered as successive volcanic/tectonic episodes typical of a fast spreading ridge. Further, the observations support a new model for the temporal evolution of episodic hydrothermal activity. Hydrothermal convection is unstable and superficial during the volcanic stage (dykes injection). At the beginning of the teaonic stage (graben formation) faults allow deep circulation and hot fluid to reach the surface. As the graben widens hydrothermal activity is less important and may cease. The heat of a new volcanic episode reactivates the deep hot water circulation along the graben faults completing a cycle. 69 nouveaux sites hydrothermaux ont été découverts entre 17'5 et 18'40'5 sur quatre segments présentant des activités volcaniques et tectoniques contrastées. A 17°10'S,17025'S et 18'37'5, la ride forme un dôme et l'activité volcanique est dominante. Les émissions hydrothermales sont d'abord diffuses et de basse température, puis focalisées et de haute température. A 18°15'S la majorité des sites hydrothermaux sont inactifs dans un graben axial dépourvu de laves récentes. A 18'32'5, des laves récentes s'épanchent au fond du graben. Les circuits hydrothermaux réactivés par le nouvel épisode volcanique se traduisent par des diffusions sur les laves récentes et par une reprise des émissions de haute température le long des murs du graben. Ces quatre segments traduisent des épisodes volcanoltectoniques successifs, caractéristiques de I'évolution temporelle des dorsales rapides. Les observations permettent de proposer un nouveau modèle de l'activité hydrothermale. Les circuits hydrothermaux sont diffus, peu structurés, instables et superficiels durant les épisodes volcaniques. Au début des épisodes tectoniques, les failles du graben drainent les fluides chauds en profondeur, puis lorsque le graben s'élargit, l'activité s'interrompt. La reprise de l'activité volcanique réamorce les circulations profondes le long des failles du graben. Comptes Rendus de l'Academie des Sciences Serie II (1251-8069) (Gauthier-villars), 1994-12 , Vol. 319 , N. 11 , P. 1399-1406 Droits : Académie des Sciences http://archimer.ifremer.fr/doc/00183/29455/27889.pdf http://archimer.ifremer.fr/doc/00183/29455/ | Partager Voir aussi Hydrothermalisme Océan Dorsales rapides Min6ralisations sulfurées. HYDROTHERMAL ACTIVITY OCEAN FAST SPREADING RIDGES SULFIDES Télécharger |
![]() | Novel microbial communities of the Haakon Mosby mud volcano and their role as a methane sink Auteur(s) : Niemann, H Losekann, T De Beer, D Elvert, M Nadalig, T Knittel, K Amann, R Sauter, E Éditeur(s) : Nature Résumé : Mud volcanism is an important natural source of the greenhouse gas methane to the hydrosphere and atmosphere(1,2). Recent investigations show that the number of active submarine mud volcanoes might be much higher than anticipated ( for example, see refs 3 - 5), and that gas emitted from deep-sea seeps might reach the upper mixed ocean(6-8). Unfortunately, global methane emission from active submarine mud volcanoes cannot be quantified because their number and gas release are unknown(9). It is also unclear how efficiently methane-oxidizing microorganisms remove methane. Here we investigate the methane-emitting Haakon Mosby Mud Volcano (HMMV, Barents Sea, 72 degrees N, 14 degrees 44' E; 1,250 m water depth) to provide quantitative estimates of the in situ composition, distribution and activity of methanotrophs in relation to gas emission. The HMMV hosts three key communities: aerobic methanotrophic bacteria (Methylococcales), anaerobic methanotrophic archaea (ANME-2) thriving below siboglinid tubeworms, and a previously undescribed clade of archaea (ANME-3) associated with bacterial mats. We found that the upward flow of sulphate- and oxygen-free mud volcano fluids restricts the availability of these electron acceptors for methane oxidation, and hence the habitat range of methanotrophs. This mechanism limits the capacity of the microbial methane filter at active marine mud volcanoes to <40% of the total flux. Nature (depuis 1997) (0028-0836) (Nature), 2006-10 , Vol. 443 , N. 7113 , P. 854-858 Droits : 2006 Nature Publishing Group http://archimer.ifremer.fr/doc/2006/publication-4514.pdf DOI:10.1038/nature05227 http://archimer.ifremer.fr/doc/00000/4514/ | Partager |
![]() | Probiotic P-acidilactici application in shrimp Litopenaeus stylirostris culture subject to vibriosis in New Caledonia Auteur(s) : Castex, Mathieu Chim, Liet Pham, Dominique Lemaire, Pierrette Wabete, Nelly Nicolas, Jean-louis Schmidely, P Mariojouls, C Éditeur(s) : Elsevier Résumé : We studied the effects of a lactic acid bacterium, Pediococcus acidilactici (strain MA 18/5M, CNCM), as a dietary probiotic on growth performance and some nutritional and microbiological aspects of the shrimp Litopenaeus stylirostris. Experimental shrimp culture was carried out over 10 weeks, using floating cages of 14 m(2) each set in earthen ponds, in a New Caledonia farm affected by "Summer syndrome", a septicaemic vibriosis caused by Vibrio nigripulchritudo. The experiment design testing probiotic-coated pellets against control was replicated in two earthen ponds. High mortalities, characteristic of Summer syndrome, were observed during the first 2 weeks of the trial. The probiotic improved production in the treated cages from both ponds with increases in the survival rate (7% and 15% respectively) and final biomass (8% and 12% respectively). No differences were recorded among treatments on growth performances, but significant lower food conversion ratios were obtained with probiotic treatment. After 5 weeks of rearing, the Hepatosomatic Index and the adjusted dry weight of the digestive gland were significantly increased by 10% and by 9% respectively in shrimps treated with probiotic. In the meantime, the specific activities of alpha amylase and trypsin in the digestive gland showed a significant effect of the probiotic treatment with respective increases by 35% and 55%. The rise in total trypsin activity following morning feeding was also enhanced by the probiotic treatment (P < 0.001). The highest concentration of probiotic (between 10(4)-10(5) CFU g(-1) of fresh gut) in the shrimp gut was obtained 2 h after feeding. The concentration remained high for 4 h after feeding before decreasing until the next meal. Total bacterial counts on Marine agar and TCBS in the gut were significantly lowered by the probiotic treatment over the 10 weeks of the experiment. Additionally, during the first 2 weeks, prevalence and load of V nigripulchritudo strains in haemolymph was lower in animals fed with the probiotic diet. This study demonstrated, under pond conditions, that feeding shrimp with live terrestrial lactic acid bacteria can be an effective treatment for improving shrimp culture affected by vibriosis. (c) 2008 Elsevier B.V. All rights reserved. Aquaculture (0044-8486) (Elsevier), 2008-03 , Vol. 275 , N. 1-4 , P. 182-193 Droits : 2008 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/2008/publication-4079.pdf DOI:10.1016/j.aquaculture.2008.01.011 http://archimer.ifremer.fr/doc/00000/4079/ | Partager |
![]() | Waterborne nickel bioaccumulation in Gammarus pulex: Comparison of mechanistic models and influence of water cationic composition Auteur(s) : Lebrun, Jeremie D. Perret, Marine Uher, Emmanuelle Tusseau-vuillemin, Marie-helene Gourlay-france, Catherine Éditeur(s) : Elsevier Science Bv Résumé : The biodynamic and saturation models offer promising lines of enquiry to predict the bioaccumulation of metals by aquatic organisms. However, in order to construct these models, the accumulation strategies have to be defined for each metal/organism couple in controlled conditions. This study aims at modelling the waterborne bioaccumulation of Ni and the influence of the water's geochemical properties on this process in a crustacean that is widely distributed in Europe, Gammarus pulex. In the laboratory, G. pulex was exposed to several Ni concentrations (from 0.001 to 100 mg L(-1)) in aquatic microcosms. Our results show that G. pulex is very tolerant to Ni (LC50(48 h) = 477 mg L(-1) Ni). Time course experiments enabled the construction of a biodynamic model by determining the uptake (k(u)) and elimination (k(e)) rate constants. When the exposure concentration exceeded 1 mg L(-1) Ni, the metal uptake reached a maximum due to a limited number of binding sites for Ni. Therefore, the organism's maximal capacity to accumulate the metal (B(max)) and the half-saturation constant (K) were determined to establish the saturation model. We showed that the two models are comparable for the lowest exposure concentrations (<1 mg L(-1) Ni), with k(u)/k(e) = B(max)/K. Then, the bioaccumulation of Ni was recorded in waters exhibiting various concentrations of three major ions (Na(+), Mg(2+) and Ca(2+)). Only Ca had an inhibitory effect on the Ni uptake. This study reports for the first time the bioaccumulation of Ni in G. pulex. Because of its high tolerance to Ni and its high capacity to accumulate this metal, this crustacean could be used as an indicator of Ni bioavailability in freshwaters. (C) 2011 Elsevier B.V. All rights reserved. Aquatic Toxicology (0166-445X) (Elsevier Science Bv), 2011-08 , Vol. 104 , N. 3-4 , P. 161-167 Droits : 2011 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00041/15217/18005.pdf DOI:10.1016/j.aquatox.2011.04.011 http://archimer.ifremer.fr/doc/00041/15217/ | Partager Voir aussi Biodynamic kinetics Saturation model Gammarid Bioavailability Water chemistry Aquatic microcosms Télécharger |
![]() | The major outer membrane protein OmpU of Vibrio splendidus contributes to host antimicrobial peptide resistance and is required for virulence in the oyster Crassostrea gigas Auteur(s) : Duperthuy, Marylise Binesse, Johan Le Roux, Frederique Romestand, Bernard Caro, Audrey Got, Patrice Givaudan, Alain Mazel, Didier Éditeur(s) : Wiley-blackwell Publishing, Inc Résumé : Vibrio splendidus, strain LGP32, is an oyster pathogen associated with the summer mortalities affecting the production of Crassostrea gigas oysters worldwide. Vibrio splendidus LGP32 was shown to resist to up to 10 mu M Cg-Def defensin and Cg-BPI bactericidal permeability increasing protein, two antimicrobial peptides/proteins (AMPs) involved in C. gigas immunity. The resistance to both oyster Cg-Def and Cg-BPI and standard AMPs (polymyxin B, protegrin, human BPI) was dependent on the ompU gene. Indeed, upon ompU inactivation, minimal bactericidal concentrations decreased by up to fourfold. AMP resistance was restored upon ectopic expression of ompU. The susceptibility of bacterial membranes to AMP-induced damages was independent of the ompU-mediated AMP resistance. Besides its role in AMP resistance, ompU proved to be essential for the adherence of V. splendidus LGP32 to fibronectin. Interestingly, in vivo, ompU was identified as a major determinant of V. spiendidus pathogenicity in oyster experimental infections. Indeed, the V. splendidus-induced oyster mortalities dropped from 56% to 11% upon ompU mutation (Kaplan Meier survival curves, P < 0.01). Moreover, in co-infection assays, the ompU mutant was out competed by the wild-type strain with competitive indexes in the range of 0.1-0.2. From this study, ompU is required for virulence of V. splendidus. Contributing to AMP resistance, conferring adhesive properties to V. splendidus, and being essential for in vivo fitness, the OmpU porin appears as an essential effector of the C. gigas/V. splendidus interaction. Environmental Microbiology (1462-2912) (Wiley-blackwell Publishing, Inc), 2010-04 , Vol. 12 , N. 4 , P. 951-963 Droits : 2010 Society for Applied Microbiology and Blackwell Publishing Ltd http://archimer.ifremer.fr/doc/00003/11421/8044.pdf DOI:10.1111/j.1462-2920.2009.02138.x http://archimer.ifremer.fr/doc/00003/11421/ | Partager |
![]() | Subcellular distribution of Ag, Cd, Co, Cu, Fe, Mn, Ph, and Zn in the digestive gland of the common cuttlefish Sepia officinalis Auteur(s) : Bustamante, Paco Bertrand, M Boucaud Camou, E Miramand, Pierre Éditeur(s) : National Shellfisheries Association Résumé : The subcellular fractionation of the digestive gland cells of the common cuttlefish Sepia officinalis was performed to investigate the distribution of metals between organelles and cytosol and the different cytosolic fractions separated by gel-filtration chromatography. Total metal concentrations vary over 3 orders of magnitude, ranging from dwt for Pb to dwt for Zn. With the exception of Cd, Co, and Cu, metals were mostly bound to the organelles. Whereas no specific organelle compartment was found for Mn, Ph, and Zn, Fe was mainly associated with nucleus, brown body, and "boule" fraction (i.e., 52%) and 44% of the total Ag was contained in the lysosomal and mitochondria enriched fraction. The link of metals with hydrosoluble proteins in the cytosolic fraction was investigated at 254 and 280 not. Direct relationship between cytosolic metal and metallothioneins could only be established for Ag and Cu, whereas Cd and Zn seem to mainly bind high (> 70 kDa) and low (< 4 kDa) molecular weight proteins. The Journal of Shellfish Research (0730-8000) (National Shellfisheries Association), 2006-12 , Vol. 25 , N. 3 , P. 987-993 Droits : 2006 NSA http://archimer.ifremer.fr/doc/2006/publication-2532.pdf http://archimer.ifremer.fr/doc/00000/2532/ | Partager 70 kDa) and low (< 4 kDa) molecular weight proteins."> 70 kDa) and low (< 4 kDa) molecular weight proteins."> 70 kDa) and low (< 4 kDa) molecular weight proteins."> 70 kDa) and low (< 4 kDa) molecular weight proteins."> | 70 kDa) and low (< 4 kDa) molecular weight proteins.">Plus Voir aussi Sepia officinalis Chromatography Metallothionein Detoxification Trace element Metal Cephalopod Télécharger |
![]() | Cross-shelf structure of coastal upwelling : a two - dimensional extension of Ekman's theory and a mechanism for inner shelf upwelling shut down Auteur(s) : Estrade, Philippe Marchesiello, P Colin De Verdiere, A Roy, C Éditeur(s) : Yale University Résumé : Sea-surface temperature images of the coastal upwelling regions off Northwest Africa show that the core of upwelling is sometimes located far from the coast. This has been documented in three regions that share a common feature, namely a wide and shallow continental shelf. This upwelling feature plays a key role in the ecology of the Canary Current System. It creates an innerfront which provides retention for biological material, e.g. fish eggs and larvae, in the highly productive nearshore environment. An analytical model has been developed based on a two dimensional extension of Ekman's solution. The linear and steady response of a homogeneous ocean forced by an upwelling-favorable wind provides a mechanism for the upwelling separation from the coast. The merging of the surface and bottom Ekman layers induces a very weak cross-shore circulation and a "kinematic barrier" for the Ekman transport divergence. In the case of an alongshore wind, the barrier is located near the isobath h ≈ 0.4D, where D is the thickness of Ekman layers. This yields an upwelling cell which is essentially concentrated in the region 0.5D < h < 1.25D, with upwelling occurring preferentially near the isobath h ≈ 0.6D. It turns out that the cross-shore width of upwelling scales with D/S, the ratio of Ekman depth to bottom topographic slope. The application of this solution to real bathymetric profiles rationalizes, not only the offshore upwelling observations in Northwest Africa, but also the influence of topography on the cross-shelf structure of a wind-driven coastal upwelling. The model also quantifies the effect of the cross-shore wind component showing how it drives the nearshore pressure gradient adjustment and how it affects the upwelling. A linear numerical experiment reproduces the theoretical steady solution, thereby allowing investigation of the transient regime. Relaxation of the hypothesis in the numerical model validates the linear assumption of the theory and then allows investigation of the sensitivity to friction parameterizations and the influence of stratification. The latter leads to an "oscillation" of the upwelling cell with seaward migration driven by outcropping and homogeneization of the water column, and, coastal incursion driven by a "boundary layers splitting" process caused by shoreward advection of the isopycnal dome and stratification of the inner shelf. Journal of Marine Research (Yale University), 2008-09 , Vol. 66 , N. 5 , P. 589-616 Droits : 2008 Yale University http://archimer.ifremer.fr/doc/2008/publication-6334.pdf DOI:10.1357/002224008787536790 http://archimer.ifremer.fr/doc/00000/6334/ | Partager |
![]() | Comparison of spaceborne measurements of sea surface salinity and colored detrital matter in the Amazon plume Auteur(s) : Fournier, Severine Chapron, Bertrand Salisbury, J. Vandemark, Douglas Reul, Nicolas Éditeur(s) : Amer Geophysical Union Résumé : Large rivers are key hydrologic components in oceanography, particularly regarding air-sea and land-sea exchanges and biogeochemistry. We enter now in a new era of Sea Surface Salinity (SSS) observing system from Space with the recent launches of the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius/Sac-D missions. With these new sensors, we are now in an excellent position to revisit SSS and ocean color investigations in the tropical northwest Atlantic using multi-year remote sensing time series and concurrent in situ observations. The Amazon is the world's largest river in terms of discharge. In its plume, SSS and upper water column optical properties such as the absorption coefficient of colored detrital matter (acdm) are strongly negatively correlated (<-0.7). Local quasi-linear relationships between SSS and acdm are derived for these plume waters over the period of 2010-2013 using new spaceborne SSS and ocean color measurements. Results allow unprecedented spatial and temporal resolution of this coupling. These relationships are then used to estimate SSS in the Amazon plume based on ocean color satellite data. This new product is validated against SMOS and in situ data and compared with previously developed SSS retrieval models. We demonstrate the potential to estimate tropical Atlantic SSS for the extended period from 1998 to 2010, prior to spaceborne SSS data collection. Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2015-05 , Vol. 120 , N. 5 , P. 3177-3192 Droits : 2015. American Geophysical Union. All Rights Reserved. http://archimer.ifremer.fr/doc/00255/36610/35742.pdf DOI:10.1002/2014JC010109 http://archimer.ifremer.fr/doc/00255/36610/ | Partager Voir aussi Amazon-Orinoco river plume SMOS SSS conservative mixing ocean color salinity satellite oceanography Télécharger |
![]() | Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea Auteur(s) : Dera, Guillaume Prunier, Jonathan Smith, Paul L. Haggart, James W. Popov, Evgeny Guzhov, Alexander Rogov, Mikhail Delsate, Dominique Éditeur(s) : Elsevier Science Bv Résumé : The breakup of Pangea and onset of growth of the Pacific plate led to several paleoenvironmental feedbacks, which radically affected paleoclimate and ocean chemistry during the Jurassic. Overall, this period was characterized by intense volcanic degassing from large igneous provinces and circum-Panthalassan arcs, new oceanic circulation patterns, and changes in heat and humidity transports affecting continental weathering. Few studies, however, have attempted to unravel the global interactions linking these processes over the long-term. In this paper, we address this question by documenting the global changes in continental drainage and surface oceanic circulation for the whole Jurassic period. For this purpose, we present 53 new neodymium isotope values (εNd(t)) measured on well-dated fossil fish teeth, ichthyosaur bones, phosphatized nodules, phosphatized ooids, and clastic sediments from Europe, western Russia, and North America. Combined with an extensive compilation of published εNd(t) data, our results show that the continental sources of Nd were very heterogeneous across the world. Volcanic inputs from a Jurassic equivalent of the modern Pacific Ring of Fire contributed to radiogenic εNd(t) values (− 4 ε-units) in the Panthalassa Ocean. For the Tethyan Ocean, the average surface seawater signal was less radiogenic in the equatorial region (− 6.3), and gradually lower toward the epicontinental peri-Tethyan (− 7.4), western Russian (− 7.4) and Euro-Boreal seas (− 8.6). Different Nd sources contributed to this disparity, with radiogenic Nd influxes from westward Panthalassan currents or juvenile volcanic arcs in open oceanic domains, and substantial unradiogenic inputs from old Laurasian and Gondwanan shields for the NW Tethyan platforms. Overall, the εNd(t) values of Euro-Boreal, peri-Tethyan, and western Russian waters varied quite similarly through time, in response to regional changes in oceanic circulation, paleoclimate, continental drainage, and volcanism. Three positive shifts in εNd(t) values occurred successively in these epicontinental seas during the Pliensbachian, in the Aalenian-Bathonian interval, and in the mid-Oxfordian. The first and third events are interpreted as regional incursions of warm surface radiogenic currents from low latitudes. The Aalenian-Bathonian shift seems linked to volcanic outbursts in the NW Tethys and/or circulation of deep currents resulting from extensional events in the Hispanic Corridor and reduced influences of boreal currents crossing the Viking Corridor. In contrast, the εNd(t) signals decreased and remained very low (< − 8) during the global warming events of the Toarcian and Late Oxfordian - Early Tithonian intervals. In these greenhouse contexts, a latitudinal expansion of humid belts could have extended the drainage pathways toward boreal Nd sources of Precambrian age and increased the supply of very unradiogenic crustal-derived inputs to seawater. Finally, a brief negative εNd(t) excursion recorded in parallel with regional drops in seawater temperature suggests that southward circulation of cold unradiogenic Arctic waters occurred in the NW Tethys in the Callovian - Early Oxfordian. All these results show that changes in surface oceanic circulation resulting from the Pangean breakup could have regionally impacted the evolution of seawater temperatures in the NW Tethys. Gondwana Research (1342-937X) (Elsevier Science Bv), 2015-06 , Vol. 27 , N. 4 , P. 1599-1615 Droits : 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved http://archimer.ifremer.fr/doc/00179/29015/27443.pdf DOI:10.1016/j.gr.2014.02.006 http://archimer.ifremer.fr/doc/00179/29015/ | Partager |
![]() | Probiotic effect of FLOC on Vibrios in the pacific white shrimp Litopenaeus Vannamei Auteur(s) : Aguilera-rivera, Diana Prieto-davo, Alejandra Escalante, Karla Chavez, Cristina Cuzon, Gerard Gaxiola, Gabriela Éditeur(s) : Elsevier Science Bv Résumé : The advantages of FLOC over clear water (CW) in rearing juvenile L. vannamei and its effects on Vibrio communities were evaluated. Survival rate in FLOC and clear water were recorded and a probiotic was tested under both conditions. Daily growth rate (DGR) was higher in FLOC (p < 0.05) than in CW. Survival in each system increased significantly when a probiotic was included in the diet (p < 0.05). The Vibrionaceae community from the hepatopancreas (HP) and the culture medium did not differ between the two culture media. Nevertheless, a novel group of Vibrio strains was found to be unique to FLOC. No high level of lesions was observed in shrimp tissues from the FLOC + probiotic treatment; it suggests that the probiotic contributed to homeostasis and prevented outbreak of opportunistic pathogenic species. Aquaculture (0044-8486) (Elsevier Science Bv), 2014-03 , Vol. 424 , P. 215-219 Droits : 2014 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00173/28379/26694.pdf DOI:10.1016/j.aquaculture.2014.01.008 http://archimer.ifremer.fr/doc/00173/28379/ | Partager |
![]() | Reproductive performance, biochemical composition and fatty acid profile of wild-caught and 2nd generation domesticated Farfantepenaeus duorarum (Burkenroad, 1939) broodstock Auteur(s) : Emerenciano, Mauricio Cuzon, Gerard Mascaro, Maite Arevalo, Miguel Norena-barroso, Elsa Jeronimo, Gilberto Racotta, Ilie Gaxiola, Gabriela Éditeur(s) : Elsevier Science Bv Résumé : A 30-day trial was performed to evaluate the reproductive performance of wild and 2nd generation domesticated Farfantepenaeus duorarum broodstock. Changes in biochemical composition and fatty acids (FA) profile in the 1st and 4th spawn order females were used as indicators of nutritional condition. Wild population of F. duorarum presented significantly better reproductive outcomes as compared to domesticated ones. Wild spawners achieved significantly higher number of eggs per spawn, number of egg per spawn per g of spawner's body weight and number of nauplii per spawn (P<0.05). Latency period was significantly shorter (P<0.05) for wild than for domesticated females (11 vs 17 days). Wild spawners also presented less mortality (6 vs 12%), higher number of total spawns (51 vs 33), spawns per ablated and per spawning females as well as higher total eggs and nauplii production. On the other hand, domesticated females presented higher number of females that spawned at least once (89 vs 76%). The higher spawning activity was reflected in lower levels of acylglycerides (AG) and cholesterol content in wild hepatopancreas (HP) and ovary (OV) (P<0.05). FA profile, mainly represented by ARA, EPA and sum of n-3 were higher in hepatopancreas and ovary of wild females, however lower levels were detected in eggs as a result of a high spawning activity. Multivariate analysis performed to detected simultaneous variation in biochemical variables indicated AG as variation pattern's responsive. (c) 2012 Elsevier B.V. All rights reserved. Aquaculture (0044-8486) (Elsevier Science Bv), 2012-05 , Vol. 344 , P. 194-204 Droits : 2012 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00079/19042/17214.pdf DOI:10.1016/j.aquaculture.2012.03.014 http://archimer.ifremer.fr/doc/00079/19042/ | Partager |
![]() | The importance and distinctiveness of small-sized phytoplankton in the Magellan Straits Auteur(s) : Zingone, Adriana Sarno, Diana Siano, Raffaele Marino, Donato Éditeur(s) : Springer Résumé : The distribution of summer phytoplankton across the Straits of Magellan (SOM) was studied with the aims of tracing differences among the distinct subregions of the area and contributing to the knowledge of its biodiversity. Samples collected at 25 stations were observed and counted in light microscopy. Selected samples were observed with transmission electron microscopy. The main unifying feature of the phytoplankton in the SOM was the high abundance and numerical dominance of small-sized (<10 μm) eukaryotic species, among which coccoid cells of <3 μm size were predominant (56.2 ± 30.6 of the total phytoplankton abundance). They mostly belonged to the prasinophyte Pycnococcus provasolii, which was abundant (0.8–6,834 cells × 103 ml−1) at all stations with the exception of those in proximity to the Atlantic entrances, where it was not recorded. Small-sized (<3 and 3–5 μm) diatoms (Minidiscus trioculatus, Lennoxia faveolata and other undetermined centric species) attained high densities (<3,757 cells 103 ml−1) especially at stations of the Patagonian sectors, whereas microplanktonic diatoms were only found at the two entrances of the Straits. Dinoflagellates were constituted mainly by >10 μm forms in the Andean subregion and <10 μm naked species in the Patagonian subregion, contributing up to 75.9 and 41.8% of the total carbon in these two areas, respectively. In the Patagonian subregion, flagellates mainly constituted by <5 μm forms and by cryptomonads <10 μm comprised up to 53.9% of the total biomass. Several species identified in this study have never been reported in other investigations in the SOM, while others, including Pycnococcus provasolii and Lennoxia faveolata, have rarely been recorded elsewhere. Overall, the summer phytoplankton of the Straits does not resemble that of any other region of the world’s seas. Although some of the predominant species might have been overlooked elsewhere, their abundance and relative importance apparently constitute a distinctive feature of the SOM. Polar Biology (0722-4060) (Springer), 2011 , Vol. 34 , N. 9 , P. 1269-1284 Droits : The Author(s) 2010. This article is published with open access at Springerlink.com http://archimer.ifremer.fr/doc/00026/13722/10828.pdf DOI:10.1007/s00300-010-0937-2 http://archimer.ifremer.fr/doc/00026/13722/ | Partager Voir aussi Lennoxia faveolata Periantarctic areas Picoeukaryotes Pycnococcus provasolii Size structure Télécharger |
![]() | Mercury in the Lot-Garonne River system (France): Sources, fluxes and anthropogenic component Auteur(s) : Schafer, Jörg Blanc, Gerard Audry, S Cossa, Daniel Bossy, C Éditeur(s) : Elsevier Résumé : Dissolved and particulate Hg fluxes in the Lot-Garonne-Gironde fluvial-estuarine system were obtained from observation of daily discharge and suspended particulate matter (SPM) concentrations. In addition to the measurements of the total dissolved (< 0.45 gm) and particulate Hg (> 0.45 gm), called HgTD and HgTp respectively, the dissolved inorganic Hg species (HgRD) were determined monthly. Geochemical background values for HgTp in sediments and SPM were similar to crustal values and to typical concentrations in SPM of non-contaminated river systems, respectively. The Riou Mort watershed already known as the origin of important historical polymetallic (e.g., Cd, Zn) pollution was identified as an important Hg point source. In the downstream Lot River, Hg concentrations were clearly higher than those in other moderately contaminated systems. The mean relative contribution of HgRD to HgTD in the Lot River and in the Garonne River was close to 25% and 50%, respectively, and showed no correlation with water discharge or SPM concentration. Depending on the origin and nature of SPM, HgTp concentrations were correlated or not with particulate organic C (POC). Maximum HgTp concentrations were measured in samples containing low POC concentrations and were attributed to sediment resuspension. In contrast, high POC concentrations (6-17%) during algal blooms were associated with low/moderate HgTp concentrations (< 0.5 mg kg(-1)) at different sites, suggesting that Hg concentrations in fluvial phytoplankton may be limited by bioavailability of dissolved Hg and/or physiologically controlled Hg accumulation. Mercury was mostly (up to 98%) transported in the particulate phase with estimated annual Hg fluxes at the outlet of the Lot River system ranging from 35 to 530 kg a(-1) for the past decade. The minimum anthropogenic component (58-84% of total Hg fluxes) could not be explained by present Riou Mort point source contributions, suggesting important Hg release from contaminated sediment as a major source and from downstream point sources (e.g., coal-fired power plants and/or metal processing industries). HgTp concentrations and fluxes were strongly related to hydrologic variations and were clearly increased by riverbed dredging during lock construction. Therefore, the estimated Hg stocks in the Lot River sediment (5-13 tons) represent an important potential Hg source for the downstream fluvial-estuarine system. Applied Geochemistry (0883-2927) (Elsevier), 2006-03 , Vol. 21 , N. 3 , P. 515-527 Droits : 2006 Elsevier Ltd All rights reserved http://archimer.ifremer.fr/doc/2006/publication-1343.pdf DOI:10.1016/j.apgeochem.2005.12.004 http://archimer.ifremer.fr/doc/00000/1343/ | Partager |
![]() | Problématique de suivi de la pêche insulaire Auteur(s) : Reynal, Lionel Maguer, Cedric Taquet, Marc Éditeur(s) : University of Miami Résumé : Insular fisheries statistics are often insufficient to allow a good management of halieutics resources. The reasons of this insufficiency, in large part, is due to inadequate methods for recording catch data and analyzing fishing effort. This presentation proposes the use of a software pro gram (<< S.P.1. ») which helps to elaborate statistics from sampling, making easier the work of personnel who are charged with producing encoded informations on insular fisheries Les statistiques des pêches insulaires sont souvent insuffisantes pour permettre une bonne gestion des ressources halieutiques. Les causes de cette insuffisance qui porte essentiellement sur les données de prise et d'effort de pêche, sont analysées dans cette étude. Des propositions sont faites pour surmonter les difficultés rencontrées. Un logiciel '« S.P.1. ») d'aide à l'élaboration de statistiques par échantillonnage est proposé pour faciliter la tâche des personnels chargés de produire en routine des informations chiffrées sur les pêches insulaires Proceedings - Gulf and Caribbean Fisheries Institute, University of Miami (0072-9019) (University of Miami), 1998 , Vol. 50 , P. 1065-1074 Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/00113/22410/20107.pdf http://archimer.ifremer.fr/doc/00113/22410/ | Partager |