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| Registros recuperados: 20 | |
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| Porteiro, F.M.; Barreiros, J.P.; Afonso, P.; Santos, R.S.; Worms, J.; Wirtz, P.. |
| Little is known about the ichthyofauna of the São Tomé and Príncipe archipelago. Since the early works of Osório, at the turn of the century, only few attempts were made to update and complete existing knowledge on fish systematics and biodiversity from this area. Over the past few years, however, several surveys made it possible to start an inventory of the coastal fishes for the archipelago. These are mainly based on specimens that where captured or observed whilst diving and also on fishes landed on beaches by local artisanal fishermen. A total of 124 species belonging to 108 genera and 61 families was identified. Some specimens, including Serranidae, Gobiidae and Labridae probably belong to undescribed species and are currently being studied. |
| Tipo: Journal Contribution |
Palavras-chave: Fishes; Gulf of Guinea; São Tomé e Principe; Checklist; Marine fish; Ichthyofauna. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/704 |
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| Sibuet, Myriam; Vangriesheim, Annick. |
| The long-term BIOZAIRE multidisciplinary deep-sea environmental program on the West Equatorial African margin organized in partnership between Ifremer and TOTAL aimed at characterizing the benthic community structure in relation with physical and chemical processes in a region of oil and gas interest. The morphology of the deep Congo submarine channel and the sedimentological structures of the deep-sea fan were established during the geological ZAIANGO project and helped to select study sites ranging from 350 to 4800 m water depth inside or near the channel and away from its influence. Ifremer conducted eight deep-sea cruises on board research vessels between 2000 and 2005. Standardized methods of sampling together with new technologies such as the ROV... |
| Tipo: Text |
Palavras-chave: Cold coral; Cold seep communities; Benthos diversity; Turbidity current; Congo canyon; Gulf of Guinea. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7349.pdf |
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| Duperron, Sebastien; Rodrigues, Clara F.; Leger, Nelly; Szafranski, Kamil; Decker, Carole; Olu, Karine; Gaudron, Sylvie M.. |
| Fauna from deep-sea cold seeps worldwide is dominated by chemosymbiotic metazoans. Recently, investigation of new sites in the Gulf of Guinea yielded numerous new species for which symbiosis was strongly suspected. In this study, symbioses are characterized in five seep-specialist metazoans recently collected from the Guiness site located at ∼600 m depth. Four bivalve and one annelid species belonging to families previously documented to harbor chemosynthetic bacteria were investigated using bacterial marker gene sequencing, fluorescence in situ hybridization, and stable isotope analyses. Results support that all five species display chemosynthetic, sulfur-oxidizing γ-proteobacteria. Bacteria are abundant in the gills of bivalves, and in the trophosome of... |
| Tipo: Text |
Palavras-chave: Acharax; Calyptogena; Chemosynthesis; Cold seeps; Elenaconcha; Gulf of Guinea; Lamellibrachia; Symbiosis; Thyasira. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00133/24418/22432.pdf |
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| Berger, Henrick; Treguier, Anne-marie; Perenne, Nicolas; Talandier, Claude. |
| In this study, we analyse the seasonal variability of the sea surface salinity (SSS) for two coastal regions of the Gulf of Guinea from 1995 to 2006 using a high resolution model (1/12°) embedded in a Tropical Atlantic (1/4°) model. Compared with observations and climatologies, our model demonstrates a good capability to reproduce the seasonal and spatial variations of the SSS and mixed layer depth. Sensitivity experiments are carried out to assess the respective impacts of precipitations and river discharge on the spatial structure and seasonal variations of the SSS in the eastern part of the Gulf of Guinea. In the Bight of Biafra, both precipitations and river runoffs are necessary to observe permanent low SSS values but the river discharge has the... |
| Tipo: Text |
Palavras-chave: Gulf of Guinea; Salinity; Modelling; Congo; Bight of Biafra; Mixed layer budget. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30493/29215.pdf |
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| Von Cosel, Rudo; Olu, Karine. |
| Two new genera and three new species of large Vesicomyidae are described from cold-seep sites on pockmarks and other sulfide-rich environments in the Gulf of Guinea (tropical east Atlantic) off Gabon, Congo (Brazzaville) and northern Angola, from 500 to 4000 m depth: "Catyptogena" (s.l.) regab n. sp., Wareniconcha (n.g.) guineensis (Thiele and Jaeckel 1931), Elenaconcha guiness n.g. n. sp., and Isorropodon atalantae n. sp. For two other species already taken by the R/V Valdivia in 1898, Calyptogena valdiviae (Thiele and Jaeckel 1931) and Isorropodon striatum (Thiele and Jaeckel 1931) new localities were discovered, and the species are rediscussed. E. guiness n.g. n.sp. is also recorded from off Banc d'Arguin, Mauritania, collected by commercial fishing... |
| Tipo: Text |
Palavras-chave: New Taxa; Systematics; Eastern Atlantic; Gulf of Guinea; Cold seeps; Vesicomyidae. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7443.pdf |
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| Le Loeuff, P; Intes, A. |
| Benthic communities of the shrimp (Penaeus notialis) grounds off Grand-Bassam, Cote-d'Ivoire, exhibit distinct variations, correlated to annual changes in hydroclimate, characterized by warm and cold (upwelling) seasons. These changes appear to be the result of the well-defined reproduction periods of many short-living benthic species, as clearly shown by the peaks of abundance in the samples, at different times of the year, but quite often at the end of the cold and the beginning of the warm seasons (September-November). Many species show marked diel rhythms, either diurnal (pagurids, brachyurans) or nocturnal (macrurans, brachyurans, molluscs), so that the species composition displays distinct differences between day and night samples (February 1970... |
| Tipo: Text |
Palavras-chave: Faune benthique; Golfe de Guinée; Cycle saisonnier; Cycle circadien; Perturbation; Benthic fauna; Gulf of Guinea; Seasonal cycle; Diel cycle; Perturbation. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00325/43601/43985.pdf |
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| Baldrighi, Elisa; Vanreusel, A.; Zeppilli, Daniela; Sandulli, R.; Segonzac, Michel. |
| Several individuals belonging to a new species of the genus Chromadorita (Nematoda: Adenophorea) were collected in a cold-seep area in the Gulf of Guinea during two French cruises: BIOZAIRE 2 (2001) and BIOZAIRE 3 (2003-2004) on board the R/V L'Atalante. In this area, rich chemosynthetic benthic communities have been discovered at 3150 m depth in the large pockmark field named Regab. Chromadorita regabi sp. nov. was found among the eggs in ovigerous specimens of the shrimp Alvinocaris muricola. The combination of long size (1500-2200 mu m), nine strong preanal papillae and relatively small dorsal tooth with weak musculature distinguishes this species from all known congeneric ones. An identification key to all known species of Chromadorita is provided. |
| Tipo: Text |
Palavras-chave: Chromadorita regabi; Cold seep; Gulf of Guinea; Alvinocaris muricola. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00454/56599/58271.pdf |
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| Guiavarc'H, Catherine; Treguier, Anne-marie; Vangriesheim, Annick. |
| Current meter measurements on the continental slope of the Gulf of Guinea (at 7 degrees 20'S and 1300 m depth) have revealed biweekly oscillations of the currents, bottom intensified and oriented along the bathymetry. We develop a three-dimensional primitive equation model of the Gulf of Guinea to study the oscillations and their forcing mechanism. The high resolution (1/12 degrees) regional model reproduces remarkably well the main characteristics of the deep currents on the continental slope. Experiments with different forcings demonstrate that the biweekly variability at 1300 m depth is remotely forced by equatorial winds. Deep Yanai waves generated by the wind propagate eastward along the equator. Upon reaching the African coast, the energy propagates... |
| Tipo: Text |
Palavras-chave: Gulf of Guinea; Numerical modeling; Coastal trapped waves. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4476.pdf |
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| Kouame Kanga, Désiré; Kouassi Aka, Marcel; Trokourey, Albert; Toualy, Elisée; N’guessan, Benjamin K.; Brehmer, Patrice; Ostrowski, Marek. |
| The spatial and seasonal variability of the mixed layer depth (MLD) was studied using hydrological data from several databases collected over the period October 1973 to March 2017 at 10 °W between latitudes 2 °N and 10 °S in the Gulf of Guinea. The density threshold method with 0.03 kg m-3 criterion was used to calculate the MLD. In the equatorial band, the seasonal average MLD is 20 m whatever the season. At 6 °S and 10 °S, the MLD is relatively higher during the cold season. The MLD varies between 21 and 37 m at 6 °S, and the seasonal averages MLD are 21 and 40 m respectively during the hot and cold seasons. At 10 °S, during the hot season, the MLD varies between 28 and 52 m and the seasonal average is 39.5 m. During the cold season, the MLD varies... |
| Tipo: Text |
Palavras-chave: Atlantic Ocean; Gulf of Guinea; Mixed Layer; Spatial Variability; Seasonal Variability.. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00684/79619/82344.pdf |
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| Menot, Lenaick; Galeron, Joelle; Olu, Karine; Caprais, Jean-claude; Crassous, Philippe; Khripounoff, Alexis; Sibuet, Myriam. |
| The structure and familial-level composition of macrofaunal communities were examined within and at distance from the giant pockmark Regab in the Southern Gulf of Guinea, at 3200 m depth. The two main questions addressed in this study were (i) does habitat partitioning by large symbiont-bearing taxa. influence macrofaunal assemblages and their environment? and (ii) to what extent does the chemosynthesis-based ecosystem influence the structure and the composition of nearby macrobenthic communities? Along two radials, at sites from 250 to 1000 m away from the active centre of the cold seep, the abundance and composition of the macrofauna were typical of a deep-sea community at that depth. Except for a few cores sampled in or near dead vesicomyid fields at... |
| Tipo: Text |
Palavras-chave: Cold seep; Diversity; Gulf of Guinea; Habitat heterogeneity; Macrofauna; Open slope; Siboglinid tubeworms; Vesicomyid clams. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00002/11282/8099.pdf |
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| Nubi, O. A.; Oyatola, O.o; Bonou, F. |
| In attempt to study the spatial differences in autumnal equatorial upwelling intensity relative to bio-productivity in the eastern equatorial Atlantic, oceanographic in situ data along regions 10°W, 0°E, 2.5°E and 6°E, collected in the Gulf of Guinea during autumn cruise carried out in September 2007 were analyzed. The surface mean values for temperature along 10°W, 0°E, 2.5°E and 6°E are 25.02, 26.15, 26.88 and 25.60°C, respectively. There was eastward weakening of the equatorial undercurrent from 10°W until its complete disappearance at 6°E. The highest concentration of nitrate recorded at the surface at 10°W was attributed to the shoaling pycnocline observed at this region. The surface mean values for nitrate along 10°W, 0°E, 2.5°E and 6°E are 0.37,... |
| Tipo: Text |
Palavras-chave: Vertical mixing; Zonal advection; Equatorial undercurrent; Equatorial upwelling; Gulf of Guinea; Nutrients; Phytoplankton biomass; Surface enrichment.. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00621/73318/72485.pdf |
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| Guillon, Erwan; Menot, Lenaick; Decker, Carole; Krylova, Elena; Olu, Karine. |
| The high biodiversity found at cold seeps, despite elevated concentrations of methane and hydrogen sulfide, is attributed to multiple sources of habitat heterogeneity. In addition to geological and geochemical processes, biogenic habitats formed by large symbiont-bearing taxa, such as bivalves and siboglinid tubeworms, or by microbial mats drive the biodiversity of small-sized fauna. However, because these habitat-forming species also depend on geochemical gradients, the respective influence of abiotic and biotic factors in structuring associated macrofaunal communities is often unresolved. The giant pockmark Regab located at 3200 m depth on the Congo margin is characterized by different fluid-flow regimes, providing a mosaic of the most common biogenic... |
| Tipo: Text |
Palavras-chave: Cold-seep; Macrofauna; Diversity; Dynamics; Vesicomyid clams; Gulf of Guinea. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00361/47210/47165.pdf |
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| Khripounoff, Alexis; Caprais, Jean-claude; Decker, Carole; Essirard, Mikael; Le Bruchec, Julie; Noel, Philippe; Olu, Karine. |
| We have studied two species of vesicomyid bivalves inhabiting different areas of sulfide-rich sediments in association with methane seepage at two pockmarks located at about 650 m and 3150 m depth, respectively, along the Gabon-Congo margin, and organic-rich sediments in the deepest zone (4950 m depth) of the Congo deep-sea fan. Benthic chambers Calmar were deployed on three study sites to assess gas and solute exchanges at the water-sediment interface. We recorded in situ measurements of oxygen, total carbon dioxide, ammonium, methane, and sulfide in two clam beds at each site. At all sites, irrespective of which the vesicomyid species are present, oxygen consumption was high and variable (28–433 mmol m−2 d−1) as was total carbon dioxide emission (36–1857... |
| Tipo: Text |
Palavras-chave: Benthic chamber; Cold-seep ecosystem; Reduced sediment; Gas fluxes; Vesicomyid bivalves; Gulf of Guinea. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00226/33746/32160.pdf |
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| Registros recuperados: 20 | |
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