Consulta: subjectFacets:"Congo canyon"
Registros recuperados: 6
Data/hora: 16/06/2024 06:48:19

Rapid transport and high accumulation of amorphous silica in the Congo deep-sea fan: A preliminary budget
Provedor de dados: 5
Autores: Raimonet, Melanie; Ragueneau, Olivier; Jacques, Vincent; Corvaisier, Rudolph; Moriceau, Brivaela; Khripounoff, Alexis; Pozzato, Lara; Rabouille, Christophe.
Mechanisms controlling the transfer and retention of silicon (Si) along continental margins are poorly understood, but play a major role in the functioning of coastal ecosystems and the oceanic biological pump of carbon. Deep-sea fans are well recognized as carbon sink spots, but we lack knowledge about the importance of the fans in the global Si cycle. Here, we provide a first estimate of the role played by the Congo deep-sea fan, one of the biggest in the world, in the Si cycle. Sediment cores sampled in the deep-sea fan were analyzed to build a Si mass balance. An exceptionally high accumulation rate of amorphous silica aSiO(2) (2.29 +/- 0.58 mol Si m(-2) y(-1)) was found, due to a high sedimentation rate and the presence of aluminum in the sediments....
Tipo: Text
Palavras-chave: Continental margin; Land-sea export; Silica cycle; Congo canyon; Deep-sea fan.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00251/36242/35797.pdf

Turbidity events observed in situ along the Congo submarine channel
Provedor de dados: 5
Autores: Vangriesheim, Annick; Khripounoff, Alexis; Crassous, Philippe.
As part of the multidisciplinary programme BIOZAIRE devoted to studying deep-sea benthic ecosystems in the Gulf of Guinea, particulate input and its relationship with near-bottom hydrodynamics were monitored using long-term moorings from 2000 to early 2005. Particular attention was given to material input through the Congo (ex-Zaïre) submarine channel that extends 760 km from the Congo River mouth to the abyssal plain (&gt;5100 m) near 6°S. Due to its direct connection to the Congo River, the Congo canyon and channel system are characterised by particularly active recent sediment transport. During this first in situ long-term monitoring along the channel, an energetic turbidity event was observed in January 2004 at three locations along the channel from...
Tipo: Text
Palavras-chave: Suspended sediment transport; Turbidity current; Deep current; Congo canyon; Zaïre; Gulf of Guinea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6738.pdf

Deep-sea environment and biodiversity of the West African Equatorial margin
Provedor de dados: 5
Autores: 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

Deep-sea habitat heterogeneity influence on meiofaunal communities in the Gulf of Guinea
Provedor de dados: 5
Autores: Van Gaever, Saskia; Galeron, Joelle; Sibuet, Myriam; Vanreusel, Ann.
To estimate the degree of spatial heterogeneity of benthic deep-sea communities, we carried out a multiple-scale (from m's to 200km) investigation in the Congo-Angola margins (Equatorial West African margin, 3150-4800 m) in which we examined the metazoan meiofauna at a variety of habitats along the Congo Channel system and in the associated cold seep. We investigate the structure, density, vertical distribution patterns in the sediment and biomass of meiofaunal communities in the Gulf of Guinea and how they are controlled by hydrologic and biogeochemical processes The meiofaunal. communities in the Gulf of Guinea were shaped by heterogeneous conditions on the margin, and reflect the multiple-scale spatial variability that corresponds with the different...
Tipo: Text
Palavras-chave: Gulf of Guinea; Nematodes; Meiofauna; Cold seep; Congo canyon; West equatorial Africa margin deep sea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7483.pdf

The influence of Congo River discharges in the surface and deep layers of the Gulf of Guinea
Provedor de dados: 5
Autores: Vangriesheim, Annick; Pierre, C; Aminot, Alain; Metzl, N; Baurand, F; Caprais, Jean-claude.
The main feature of the Congo-Angola margin in the Gulf of Guinea is the Congo (ex-Zaire) deep-sea fan composed of a submarine canyon directly connected to the Congo River, a channel and a [sediment] lobe area. During the multi-disciplinary programme called BIOZAIRE conducted by Ifremer from 2000 to 2005, two CTD-O2 sections with discrete water column samples were performed (BIOZAIRE3 cruise: 2003-2004) to study the influence of the Congo River discharges, both in the surface layer and in the deep and near-bottom layers. The surface layer water is greatly diluted with river water that has a heavy particle load. The deep layer is affected by episodic turbidity currents that flow in the deep Congo channel and reach deep areas far from the coast. Previous...
Tipo: Text
Palavras-chave: DIC; Stable isotopes; Nutrient anomaly; Oxygen anomaly; Congo canyon; Gulf of Guinea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6737.pdf

Spatial and temporal patterns of benthic macrofaunal communities on the deep continental margin in the Gulf of Guinea
Provedor de dados: 5
Autores: Galeron, Joelle; Menot, Lenaick; Renaud, Nolwenn; Crassous, Philippe; Khripounoff, Alexis; Treignier, C.; Sibuet, M.
Density, taxonomic composition at higher taxon level and vertical distribution of benthic macrofaunal communities and sediment characteristics (pore water, nitrogen, organic carbon, sulfur, C/N ratio, n-alcohol biomarkers) were examined at three deep sites on the Congo-Gabon continental margin. This study was part of the multidisciplinary BIOZAIRE project that aimed at studying the deep benthic ecosystems in the Gulf of Guinea. Sampling of macrofaunal communities and of sediment was conducted during three cruises (January 2001, December 2001 and December 2003) at two downslope sites (4000 m depth), one located near the Congo submarine channel (15 km in the south) and the other one far from the channel (150km in the South). The third area located 8 km north...
Tipo: Text
Palavras-chave: Deep sea; Distribution; Community structure; Macrofauna; Congo canyon; Congo Angola margin; Equatorial west Africa margin; Atlantic.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7315.pdf