230 results on '"Khripounoff, A."'
Search Results
2. Mn-micronodules from the sediments of the Clarion-Clipperton zone (Pacific Ocean): Origin, elemental source, and Fe-Cu-Zn-isotope composition
- Author
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Dekov, Vesselin M., Rouxel, Olivier, Guéguen, Bleuenn, Wegorzewski, Anna V., Khripounoff, Alexis, and Menot, Lénaïck
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- 2021
- Full Text
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3. Geochemical and Biological Recovery of the Disturbed Seafloor in Polymetallic Nodule Fields of the Clipperton-Clarion Fracture Zone (CCFZ) at 5,000-m Depth
- Author
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Khripounoff, Alexis, Caprais, Jean-Claude, Crassous, Philippe, and Etoubleau, Joël
- Published
- 2006
4. Molecular and Morphological Identification of Settlement-Stage Vent Mussel Larvae, Bathymodiolus azoricus (Bivalvia: Mytilidae), Preserved in Situ at Active Vent Fields on the Mid-Atlantic Ridge
- Author
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Comtet, Thierry, Jollivet, Didier, Khripounoff, Alexis, Segonzac, Michel, and Dixon, David R.
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- 2000
5. Variability in gas and solute fluxes through deep-sea chemosynthetic ecosystems inhabited by vesicomyid bivalves in the Gulf of Guinea
- Author
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Khripounoff, A., Caprais, J.C., Decker, C., Essirard, M., Le Bruchec, J., Noel, P., and Olu, K.
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- 2015
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6. Deep cold-water coral ecosystems in the Brittany submarine canyons (Northeast Atlantic) : Hydrodynamics, particle supply, respiration, and carbon cycling
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Khripounoff, Alexis, Caprais, Jean-Claude, Le Bruchec, Julie, Rodier, Philippe, Noel, Philippe, and Cathalot, Cécile
- Published
- 2014
7. A review of the distribution of hydrothermal vent communities along the northern Mid-Atlantic Ridge: dispersal vs. environmental controls
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Desbruyères, D., Almeida, A., Biscoito, M., Comtet, T., Khripounoff, A., Le Bris, N., Sarradin, P. M., Segonzac, M., Dumont, H. J., editor, Jones, M. B., editor, Azevedo, J. M. N., editor, Neto, A. I., editor, Costa, A. C., editor, and Martins, A. M. Frias, editor
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- 2000
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8. Different types of sediment gravity flows detected in the Var submarine canyon (northwestern Mediterranean Sea)
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Khripounoff, A., Crassous, P., Lo Bue, N., Dennielou, B., and Silva Jacinto, R.
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- 2012
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9. Impact of open-ocean convection on particle fluxes and sediment dynamics in the deep margin of the Gulf of Lions
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M. Stabholz, X. Durrieu de Madron, M. Canals, A. Khripounoff, I. Taupier-Letage, P. Testor, S. Heussner, P. Kerhervé, N. Delsaut, L. Houpert, G. Lastras, and B. Dennielou
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Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
The deep outer margin of the Gulf of Lions and the adjacent basin, in the western Mediterranean Sea, are regularly impacted by open-ocean convection, a major hydrodynamic event responsible for the ventilation of the deep water in the western Mediterranean Basin. However, the impact of open-ocean convection on the flux and transport of particulate matter remains poorly understood. The variability of water mass properties (i.e., temperature and salinity), currents, and particle fluxes were monitored between September 2007 and April 2009 at five instrumented mooring lines deployed between 2050 and 2350-m depth in the deepest continental margin and adjacent basin. Four of the lines followed a NW–SE transect, while the fifth one was located on a sediment wave field to the west. The results of the main, central line SC2350 ("LION") located at 42°02.5′ N, 4°41′ E, at 2350-m depth, show that open-ocean convection reached mid-water depth (≈ 1000-m depth) during winter 2007–2008, and reached the seabed (≈ 2350-m depth) during winter 2008–2009. Horizontal currents were unusually strong with speeds up to 39 cm s−1 during winter 2008–2009. The measurements at all 5 different locations indicate that mid-depth and near-bottom currents and particle fluxes gave relatively consistent values of similar magnitude across the study area except during winter 2008–2009, when near-bottom fluxes abruptly increased by one to two orders of magnitude. Particulate organic carbon contents, which generally vary between 3 and 5%, were abnormally low (≤ 1%) during winter 2008–2009 and approached those observed in surface sediments (≈ 0.6%). Turbidity profiles made in the region demonstrated the existence of a bottom nepheloid layer, several hundred meters thick, and related to the resuspension of bottom sediments. These observations support the view that open-ocean deep convection events in the Gulf of Lions can cause significant remobilization of sediments in the deep outer margin and the basin, with a subsequent alteration of the seabed likely impacting the functioning of the deep-sea ecosystem.
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- 2013
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10. Natural and anthropogenic trace metals in sediments of the Ligurian Sea (Northwestern Mediterranean)
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Heimbürger, Lars-Eric, Cossa, Daniel, Thibodeau, Benoit, Khripounoff, Alexis, Mas, Virginie, Chiffoleau, Jean-François, Schmidt, Sabine, and Migon, Christophe
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- 2012
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11. Mixotrophy in the deep sea : a dual endosymbiotic hydrothermal mytilid assimilates dissolved and particulate organic matter
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Riou, Virginie, Colaço, Ana, Bouillon, Steven, Khripounoff, Alexis, Dando, Paul, Mangion, Perrine, Chevalier, Emilie, Korntheuer, Michael, Santos, Ricardo Serrão, and Dehairs, Frank
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- 2010
12. Dynamics of benthic copepods and other meiofauna in the benthic boundary layer of the deep NW Mediterranean Sea
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Guidi-Guilvard, L. D., Thistle, D., Khripounoff, A., and Gasparini, S.
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- 2009
13. Multiscale spatio-temporal variability of sedimentary deposits in the Var turbidite system (North-Western Mediterranean Sea)
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Mas, V., Mulder, T., Dennielou, B., Schmidt, S., Khripounoff, A., and Savoye, B.
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- 2010
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14. Temporal variation of currents, particulate flux and organism supply at two deep-sea hydrothermal fields of the Azores Triple Junction
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Khripounoff, Alexis, Vangriesheim, Annick, Crassous, Philippe, Segonzac, Michel, Lafon, Virginie, and Warén, Anders
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- 2008
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15. Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
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Martial Taillefert, Karine Olu, Mélanie Raimonet, Lucie Pastor, Jean-Louis Reyss, Olivier Ragueneau, Philippe Martinez, Laurence Méjanelle, Laurence Droz, P. Michalopoulos, Elsa Stetten, François Baudin, Christophe Rabouille, Bernard Dennielou, Audrey M. Pruski, Johann Schnyder, Julie Tourolle, Alexis Khripounoff, Livio Ruffine, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Océan et Interfaces (OCEANIS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement Profond (LEP), Etudes des Ecosystèmes Profonds (EEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Hellenic Centre for Marine Research (HCMR), Paléoenvironnemements Paléoclimats, Bassins (ISTEP-PPB), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], ANR-11-BS56-0030,CONGOLOBE,Transfert de carbone organique et fonctionnement des écosystèmes dans les lobes terminaux de l'éventail sous-marin du Congo(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Unité de recherche Géosciences Marines (Ifremer) (GM), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), IFREMER- Département Etude des Ecosystèmes Profonds (DEEP/LEP), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Conception, Optimisation et Modélisation des Systèmes (LCOMS), Université de Lorraine (UL), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS)
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010506 paleontology ,Archeology ,Biogeochemical cycle ,010504 meteorology & atmospheric sciences ,Geochemistry ,Sedimentology-marine cores ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Submarine canyon ,01 natural sciences ,Deep sea ,South Atlantic ,Paleoceanography ,Organic geochemistry ,14. Life underwater ,Glacial period ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Total organic carbon ,Present ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,ACL ,Geology ,Last Glacial Maximum ,13. Climate action ,Inorganic geochemistry ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology - Abstract
International audience; Carbon and silicon cycles at the Earth surface are linked to long-term variations of atmospheric CO2 and oceanic primary production. In these cycles, the river-sea interface is considered a biogeochemical hotspot, and deltas presently receive and preserve a major fraction of riverine particles in shallow water sediments. In contrast, periods of glacial maximum lowstand were characterized by massive exports of sediments to the deep-sea via submarine canyons and accumulation in deep-sea fans. Here, we calculate present-day mass balances for organic carbon (OC) and amorphous silica (aSi) in the terminal lobe complex of the Congo River deep-sea fan as an analogue for glacial periods. We show that this lobe complex constitutes a megasink with the current accumulation of 18 and 35% of the OC and aSi river input, respectively. This increases the estimates of organic carbon burial by 19% in the South Atlantic Ocean in a zone representing less than 0.01% of the basin. These megasinks might have played a role in carbon trapping in oceanic sediments during glacial times.
- Published
- 2019
16. Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
- Author
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Rabouille, C., Dennielou, B., Baudin, F., Raimonet, M., Droz, L., Khripounoff, A., Martinez, P., Mejanelle, L., Michalopoulos, P., Pastor, L., Pruski, A., Ragueneau, O., Reyss, J.-L., Ruffine, L., Schnyder, J., Stetten, E., Taillefert, M., Tourolle, J., and Olu, K.
- Published
- 2019
- Full Text
- View/download PDF
17. Downward particle fluxes within different productivity regimes off the Mauritanian upwelling zone (EUMELI program)
- Author
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Bory, A., Jeandel, C., Leblond, N., Vangriesheim, A., Khripounoff, A., Beaufort, L., Rabouille, C., Nicolas, E., Tachikawa, K., Etcheber, H., and Buat-Menard, P.
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Mauritania -- Environmental aspects ,North Atlantic Ocean -- Environmental aspects ,Eutrophication -- Research ,Marine productivity -- Research ,Upwelling (Oceanography) -- Research ,Earth sciences - Abstract
Research indicates that downward particle flux in the North Atlantic Ocean, near the Mauritanian upwelling zone, is correlated with westward surface currents. These currents are likely to transport biomass-rich water masses seaward from coastal regions. Upwelling influence is strongest at the coastal mesotrophic site.
- Published
- 2001
18. Particle flux in the Rainbow hydrothermal vent field (Mid-Atlantic Ridge): dynamics, mineral and biological composition
- Author
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Khripounoff, Alexis, Vangriesheim, Annick, Crassous, Philippe, Segonzac, Michel, Colaco, Ana, Desbruyeres, Daniel, and Barthelemy, Roxane
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Atlantic Ocean -- Environmental aspects ,Hydrothermal vents -- Atlantic Ocean ,Sea-water -- Composition ,Biological sciences ,Earth sciences - Abstract
The ecology of the Rainbow hydrothermal vent is compared with other vents along the Mid-Atlantic Ridge (MAR) in the Atlantic Ocean. Total mean mass particle flux was significantly higher than other MAR vents. Plume composition consisted of an even distribution of pelagic and hydrothermal particles. Data were obtained from current-meters, sediment traps and thermistor chains.
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- 2001
19. Variations in deep-sea hydrothermal vent communities on the Mid-Atlantic Ridge near the Azores plateau
- Author
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Desbruyeres, D., Biscoito, M., Caprais, J.-C., Colaco, A., Comtet, T., Crassous, P., Fouquet, Y., Khripounoff, A., Le Bris, N., Olu, K., Riso, R., Sarradin, P.-M., Segonzac, M., and Vangriesheim, A.
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Atlantic Ocean -- Environmental aspects ,Hydrothermal vent ecology -- Research ,Earth sciences - Abstract
Research on Atlantic Ocean hydrothermal vents around the Azores plateau suggests that vent fluid toxicity changes and suspended mineral particles produce composition and structure variations in hydrothermal vent communities at the depth gradient. Vents included in the study were the Rainbow, Menez Gwen and Lucky Strike vents.
- Published
- 2001
20. Respiration of bivalves from three different deep-sea areas: Cold seeps, hydrothermal vents and organic carbon-rich sediments
- Author
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Jean-Claude Caprais, Carole Decker, J. Le Bruchec, Philippe Noel, Bérengère Husson, and Alexis Khripounoff
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0106 biological sciences ,Total organic carbon ,Vesicomyid and Mytilid bivalves ,010504 meteorology & atmospheric sciences ,010604 marine biology & hydrobiology ,Deep-sea ,Hydrothermal vent ,Sediment ,Oceanography ,Cold seep ,01 natural sciences ,Deep sea ,Methane ,chemistry.chemical_compound ,Benthic chamber ,chemistry ,Benthic zone ,Respiration rate ,Carbon dioxide ,14. Life underwater ,Geology ,0105 earth and related environmental sciences - Abstract
We studied bivalves (vesicomyids and mytilids) inhabiting four different areas of high sulfide and methane production: (1) in the Gulf of Guinea, two pockmarks (650 m and 3150 m depth) and one site rich in organic sediments in the deepest zone (4950 m average depth), (2) at the Azores Triple Junction on the Mid-Atlantic Ridge, one hydrothermal site (Lucky Strike vent field, 1700 m depth). Two types of Calmar benthic chambers were deployed, either directly set into the sediment (standard Calmar chamber) or fitted with a tank to isolate organisms from the sediment (modified Calmar chamber), to assess gas and solute exchanges in relation to bivalve bed metabolism. Fluxes of oxygen, total carbon dioxide, ammonium and methane were measured. At the site with organic-rich sediments, oxygen consumption by clams measured in situ with the standard benthic chamber was variable (1.3–6.7 mmol m−2 h−1) as was total carbon dioxide production (1–9.6 mmol m−2 h−1). The observed gas and solute fluxes were attributed primarily to bivalve respiration (vesicomyids or mytilids), but microbial and geochemical processes in the sediment may be also responsible for some of variations in the deepest stations. The respiration rate of isolated vesicomyids (16.1–0.25.7 µmol g−1 dry weight h−1) was always lower than that of mytilids (33 µmol g−1 dry weight h−1). This difference was attributed to the presence of a commensal scaleworm in the mytilids. The respiratory coefficient (QR) ≥1 indicated high levels of anaerobic metabolism. The O:N index ranged from 5 to 25, confirming that vesicomyids and mytilids, living in symbiosis with bacteria, have a protein-based food diet.
- Published
- 2017
21. Intercalibration of benthic flux chambers: II. Hydrodynamic characterization and flux comparisons of 14 different designs
- Author
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Tengberg, A., Hall, P.O.J., Andersson, U., Lindén, B., Styrenius, O., Boland, G., de Bovee, F., Carlsson, B., Ceradini, S., Devol, A., Duineveld, G., Friemann, J.-U., Glud, R.N., Khripounoff, A., Leather, J., Linke, P., Lund-Hansen, L., Rowe, G., Santschi, P., de Wilde, P., and Witte, U.
- Published
- 2005
- Full Text
- View/download PDF
22. Ecophysiological differences between vesicomyid species and metabolic capabilities of their symbionts influence distribution patterns of the deep‐sea clams
- Author
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Alexis Khripounoff, Patricia Pignet, Cecile Cathalot, Anne Godfroy, Sophie Arnaud-Haond, Marie-Anne Cambon-Bonavita, Nicolas Gayet, Jean-Claude Caprais, Carole Decker, Adrien Vigneron, Karine Olu, Perrine Cruaud, Claire Papot, Jocelyn Le Baut, 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), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD)
- Subjects
0106 biological sciences ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Deep sea ,pliocardinae bivalve ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,evolutionary relationships ,Ecosystem ,Guaymas Basin ,14. Life underwater ,sulfur storage ,vesicomyid movements ,deep-sea ecosystems ,Ecology, Evolution, Behavior and Systematics ,Chemosynthesis ,Ecology ,biology ,hydrothermal vent clam ,010604 marine biology & hydrobiology ,marine ecology ,Community structure ,biology.organism_classification ,Cold seep ,Calyptogena magnifica ,calyptogena-magnifica ,sulfide-rich sediments ,chemoautotrophic bacteria ,cold seeps ,community structure ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,gulf-of-california ,macrofaunal communities ,Hydrothermal vent - Abstract
WOS:000472949800006; This study provides an analysis of vesicomyid bivalve-symbiont community distribution across cold seep and hydrothermal vent areas in the Guaymas Basin (Gulf of California, Mexico). Using a combination of morphological and molecular approaches including fluorescent in situ hybridization (FISH), and electronic microscopy observations, vesicomyid clam species and their associated symbionts were characterized and results were analyzed in light of geochemical conditions and other on-site observations. A greater diversity of vesicomyids was found at cold seep areas, where three different species were present (Phreagena soyoae [syn. kilmeri], Archivesica gigas, and Calyptogena pacifica). In contrast, A. gigas was the only species sampled across the hydrothermal vent area. The same haplotype of A. gigas was found in both hydrothermal vent and cold seep areas, highlighting possible contemporary exchanges among neighboring vents and seeps. In either ecosystem, molecular characterization of the symbionts confirmed the specificity between symbionts and hosts and supported the hypothesis of a predominantly vertical transmission. In addition, patterns of clams could reflect potential niche preferences for each species. The occurrence of numerous traces of vesicomyid movements on sediments in the sites colonized by A. gigas seemed to indicate that this species might have a better ability to move. Furthermore, variation in gill sulfur content could reveal a higher plasticity and sulfur storage capacity in A. gigas. Thus, the distribution of vesicomyid species across the chemosynthetic areas of the Guaymas Basin could be explained by differences in biological traits of the vesicomyid species that would allow A. gigas to more easily exploit transient and punctual sources of available sulfide than P. soyoae.
- Published
- 2019
23. Vertical and temporal variations of particle fluxes in the deep tropical atlantic
- Author
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Khripounoff, Alexis, Vangriesheim, Annick, and Crassous, Philippe
- Subjects
Atlantic Ocean -- Research ,Marine sediments -- Research ,Hydrodynamics -- Research ,Earth sciences - Abstract
A two-year study of particle fluxes at varying depths in an oligotrophic site in eastern deep tropical Atlantic was conducted to examine their vertical and temporal variations. Analyses of hydrodynamical and sediment data were performed to evaluate their effects on the carbon budget in the deep sea. Results suggest a monthly variation while a clear seasonal signal was not observed. Carbon budget measurement demonstrated that only 2% of the organic matter carried by the downward current became buried in the sediment.
- Published
- 1998
24. Fluxes and balance of 210Pb in the tropical northeast Atlantic
- Author
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Legeleux, Francoise, Reyss, Jean-Louis, Etcheber, Henri, and Khripounoff, Alexis
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North Atlantic Ocean -- Environmental aspects ,Lead -- Isotopes ,Sea-water -- Analysis ,Earth sciences - Abstract
The analysis of 210Pb budget shows that the tropical Atlantic eastern margins represent a significant sink for 210Pb. Fluxes of particulate matter collected through sediment traps indicate long-term accumulation traps. Discrepancies exist between 210Pb sediment trap-measured fluxes and 210Pb fluxes needed to support excess 210Pb inventories in bottom sediments for two sediment traps. 210Pb scavenging is affected by the major-phase composition of particulate matter in the tropical northeast Atlantic.
- Published
- 1996
25. Rapid post-bloom resuspension in the northeastern Atlantic
- Author
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Auffret, Gerard, Khripounoff, Alexis, and Vangriesheim, Annick
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Water bloom -- Analysis ,Organic wastes -- Analysis ,Earth sciences - Abstract
A study of particulate matter input on the bottom of the sea and resuspension mechanisms after spring bloom in the north Atlantic Ocean suggests that aggregate disintegration rates result in resuspension that follows high particulate matter input. The rapid disaggregation of organic matter takes place in the initial two weeks of its presence on the sea floor. Resuspension mechanisms are sensitive to vital erosion velocity and the resuspended particles undergo reaggregation and rearrangement.
- Published
- 1994
26. Particulate material degradation in sediment traps at 2000 m depth on the Meriadzeck Terrace (Bay of Biscay)
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Khripounoff, Alexis and Crassous, Philippe
- Subjects
Bay of Biscay -- Environmental aspects ,Marine sediments -- Research ,Earth sciences - Abstract
An analysis of particles obtained from poisoned and non-poisoned sediment traps placed at a 2,100 meter depth in the Bay of Biscay indicates the essentiality of trap particle preservation. Poisoned traps exhibit a reduction in calcium flux due to the impossibility of calcium precipitation in non-poisoned traps. Organic carbon degeneration in non-poisoned traps results from heterotrophic microbial activity on the particles.
- Published
- 1994
27. Direct observation of intense turbidity current activity in the Zaire submarine valley at 4000 m water depth
- Author
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Khripounoff, Alexis, Vangriesheim, Annick, Babonneau, Nathalie, Crassous, Philippe, Dennielou, Bernard, and Savoye, Bruno
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- 2003
- Full Text
- View/download PDF
28. Ecophysiological differences between vesicomyid species and metabolic capabilities of their symbionts influence distribution patterns of the deep‐sea clams
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Cruaud, Perrine, primary, Decker, Carole, additional, Olu, Karine, additional, Arnaud‐Haond, Sophie, additional, Papot, Claire, additional, Le Baut, Jocelyn, additional, Vigneron, Adrien, additional, Khripounoff, Alexis, additional, Gayet, Nicolas, additional, Cathalot, Cécile, additional, Caprais, Jean‐Claude, additional, Pignet, Patricia, additional, Godfroy, Anne, additional, and Cambon‐Bonavita, Marie‐Anne, additional
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- 2019
- Full Text
- View/download PDF
29. Hydrothermal plume-particle fluxes at 13°N on the East Pacific Rise
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German, C.R, Colley, S, Palmer, M.R, Khripounoff, A, and Klinkhammer, G.P
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- 2002
- Full Text
- View/download PDF
30. Variability in gas and solute fluxes through deep-sea chemosynthetic ecosystems inhabited by vesicomyid bivalves in the Gulf of Guinea
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Philippe Noel, J. Le Bruchec, Alexis Khripounoff, Karine Olu, M. Essirard, Carole Decker, and Jean-Claude Caprais
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0106 biological sciences ,Gulf of Guinea ,010504 meteorology & atmospheric sciences ,Sulfide ,Cold-seep ecosystem ,Hydrogen sulfide ,Gas fluxes ,Aquatic Science ,Oceanography ,01 natural sciences ,Deep sea ,Methane ,chemistry.chemical_compound ,14. Life underwater ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Chemosynthesis ,010604 marine biology & hydrobiology ,Sediment ,15. Life on land ,Reduced sediment ,Vesicomyid bivalves ,Benthic chamber ,chemistry ,13. Climate action ,Benthic zone ,Environmental chemistry ,Carbon dioxide ,Geology - Abstract
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 mmol m −2 d −1 ). Consequently, the respiratory coefficient also varied greatly, ranging from 0.2 to 5.4. The observed gas and solute fluxes were attributed primarily to the respiration of clams, but microbial and geochemical processes in the sediment may be also responsible for some of the variation among sites. Ammonium production (7.5–71.8 mmol m −2 d −1 ) was associated predominantly with nitrogen excretion resulting from vesicomyid metabolism. The O:N index ranged from 2 to 17 indicating that the vesicomyid clams, living in symbiosis with bacteria, have a protein-based metabolism. The cold-seep and organic-rich sediment ecosystems were fuelled by methane expelled from the sediment; methane emission varied from 1.8 to 139 mmol m −2 d −1 , independently of bivalve biomass. Significant sulfide emission from the sediment was observed only at the shallowest station (156 mmol m −2 d −1 ). Our in situ measurements confirm that the vesicomyid bivalves have a high capacity for growth and survival across a large gradient of methane and hydrogen sulfide fluxes that occur at 700 m to 5000 m depth.
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- 2015
31. Rapid transport and high accumulation of amorphous silica in the Congo deep-sea fan: A preliminary budget
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Olivier Ragueneau, Christophe Rabouille, Mélanie Raimonet, Lara Pozzato, Vincent Jacques, Alexis Khripounoff, Brivaëla Moriceau, Rudolph Corvaisier, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Laboratoire Environnement Profond (LEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Etudes des Ecosystèmes Profonds (EEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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Geochemistry ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Aquatic Science ,Oceanography ,Congo canyon ,Continental margin ,14. Life underwater ,Ecology, Evolution, Behavior and Systematics ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Canyon ,geography ,geography.geographical_feature_category ,Deep-sea fan ,Continental shelf ,ACL ,Bioirrigation ,Biological pump ,Sediment ,Carbon sink ,Sedimentation ,[SDE]Environmental Sciences ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Land-sea export ,Silica cycle ,Geology - Abstract
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. Although favored by bioirrigation, recycling fluxes remained low (0.3 mol Si m − 2 y − 1 ) and reconstructed input fluxes could only be explained by lateral inputs coming from the canyon. Preliminary calculations show that the rapid transport of aSiO 2 through the canyon and the excellent preservation efficiency in the sediments imply that 50% of aSiO 2 river inputs from the Congo River accumulate annually in the deep-sea fan. Si:C ratios in deep-sea fan sediments were very low (0.2) and only three times as high as those measured in the river itself, which suggests that material from the river and the continental shelf was delivered directly through the canyon, with very little time for Si and C cycle decoupling to take place.
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- 2015
32. The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling
- Author
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Nicolas Gayet, Karine Charlier, Mélanie Raimonet, Olivier Ragueneau, Philippe Noel, J. Le Saout, Christophe Rabouille, Florence Savignac, Laurent Toffin, Gilles Vétion, Ming-Yi Sun, Lucie Pastor, Perrine Cruaud, S. Bourgeois, Anne Godfroy, Françoise Lesongeur, F. Toussaint, Julie Tourolle, François Baudin, Olivier Mouchel, Elsa Stetten, Philippe Rodier, Audrey M. Pruski, Martine Bez, Cecile Cathalot, Martial Taillefert, Sophie Arnaud-Haond, Lara Pozzato, Rudolph Corvaisier, Laurence Méjanelle, N. Tisnerat-Laborde, Claire Croguennec, Christophe Brandily, Philippe Martinez, Jean-Claude Caprais, Arunima Sen, Bernard Dennielou, Bruno Bombled, Sandrine Bessette, C. Senyarich, Alexis Khripounoff, Karine Olu, Laurence Droz, M. Lesaout, Marie Picot, Stéphane Hourdez, Jordon S. Beckler, J. Le Bruchec, Johann Schnyder, Patricia Pignet, Nathalie Babonneau, Livio Ruffine, M. Rabiller, J.L. Reyss, P. Michalopoulos, J.-M. Jouanneau, C. Bayle, Carole Decker, Sara Teixeira, B. Ruesch, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire Environnement Profond (LEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Evolution et Modélisation des Bassins Sédimentaires (EMBS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Laboratoire de microbiologie des environnements extrêmophiles (LM2E), Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Adaptation et Biologie des Invertébrés en Conditions Extrêmes (ABICE), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Hellenic Centre for Marine Research (HCMR), Department of Marine Sciences [Athens], University of Georgia [USA], Centre of Marine Sciences [Faro] (CCMAR), University of Algarve [Portugal], Géochrononologie Traceurs Archéométrie (GEOTRAC), TOTAL-Scientific and Technical Center Jean Féger (CSTJF), TOTAL FINA ELF, ANR-11-BS56-0030,CONGOLOBE,Transfert de carbone organique et fonctionnement des écosystèmes dans les lobes terminaux de l'éventail sous-marin du Congo(2011), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Etudes des Ecosystèmes Profonds (EEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre scientifique et Technique Jean Feger (CSTJF), and Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS)
- Subjects
Turbidity current ,Continental-Margin ,010504 meteorology & atmospheric sciences ,Fine sediment ,Sedimentation rate ,Transport ,Submarine canyon ,Vesicomyidae ,010502 geochemistry & geophysics ,Oceanography ,Turbidite ,01 natural sciences ,Deep sea ,Particulate Materials ,Guaymas Basin ,14. Life underwater ,Congo deep-sea fan ,Chemosynthetic habitats ,Turbidity-Current ,0105 earth and related environmental sciences ,Canyon ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,geography ,geography.geographical_feature_category ,ACL ,Organic-Carbon Accumulation ,Particle Fluxes ,Estuary ,Seafloor morphology ,15. Life on land ,M Water Depth ,13. Climate action ,Mud Volcano ,[SDE]Environmental Sciences ,Chemosynthetic Ecosystems ,Submarine pipeline ,Sedimentary rock ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Geology - Abstract
The presently active region of the Congo deep-sea fan (around 330,000 km(2)), called the terminal lobes or lobe complex, covers an area of 2500 km(2) at 4700-5100 m water depth and 750-800 km offshore. It is a unique sedimentary area in the world ocean fed by a submarine canyon and a channel-levee system which presently deliver large amounts of organic carbon originating from the Congo River by turbidity currents. This particularity is due to the deep incision of the shelf by the Congo canyon, up to 30 km into the estuary, which funnels the Congo River sediments into the deep-sea. The connection between the river and the canyon is unique for major world rivers. In 2011, two cruises (WACS leg 2 and Congolobe) were conducted to simultaneously investigate the geology, organic and inorganic geochemistry, and micro- and macro-biology of the terminal lobes of the Congo deep-sea fan. Using this multidisciplinary approach, the morpho-sedimentary features of the lobes were characterized along with the origin and reactivity of organic matter, the recycling and burial of biogenic compounds, the diversity and function of bacterial and archaeal communities within the sediment, and the biodiversity and functioning of the faunal assemblages on the seafloor. Six different sites were selected for this study: Four distributed along the active channel from the lobe complex entrance to the outer rim of the sediment deposition zone, and two positioned cross-axis and at increasing distance from the active channel, thus providing a gradient in turbidite particle delivery and sediment age. This paper aims to provide the general context of this multidisciplinary study. It describes the general features of the site and the overall sampling strategy and provides the initial habitat observations to guide the other in-depth investigations presented in this special issue. Detailed bathymetry of each sampling site using 0.1-1 m resolution multibeam obtained with a remotely operated vehicle (ROV) shows progressive widening and smoothing of the channel-levees with increasing depth and reveals a complex morphology with channel bifurcations, erosional features and massive deposits. Dense ecosystems surveyed in the study area gather high density clusters of two large-sized species of symbiotic Vesicomyidae bivalves and microbial mats. These assemblages, which are rarely observed in sedimentary zones, resemble those based on chemosynthesis at cold-seep sites, such as the active pockmarks encountered along the Congo margin, and share with these sites the dominant vesicomyid species Christineconcha regab. Sedimentation rates estimated in the lobe complex range between 0.5 and 10 cm yr(-1), which is 2-3 orders of magnitude higher than values generally encountered at abyssal depths. The bathymetry, faunal assemblages and sedimentation rates make the Congo lobe complex a highly peculiar deep-sea habitat driven by high inputs of terrigenous material delivered by the Congo channel-levee system. (c) 2016 Elsevier Ltd. All rights reserved. ZAIANGO ANR Congolobe (ANR Blanc SIMI5-6) [11 BS56 030] IFREMER CEA through LSCE U.S. National Science Foundation [OCE-0831156] info:eu-repo/semantics/acceptedVersion
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- 2017
33. Aliphatic hydrocarbons and triterpenes of the Congo deep-sea fan
- Author
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Jordi Dachs, François Baudin, Alexis Khripounoff, Laurence Méjanelle, Laurence Maryvonne Pinturier, Béatrice Rivière, Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Total E&P, Laboratoire Environnement Profond (LEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institute of Environmental Assessment and Water Research (IDAEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
- Subjects
Hopenes ,010504 meteorology & atmospheric sciences ,Submarine canyon ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Deep sea ,Congo fan ,Hopanes ,Sediments ,Organic matter ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,0105 earth and related environmental sciences ,Turbidite system ,chemistry.chemical_classification ,Canyon ,Total organic carbon ,geography ,geography.geographical_feature_category ,Sediment ,NAH ,Pelagic zone ,15. Life on land ,Hopanoids ,Hydrocarbons ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM] ,chemistry ,13. Climate action ,Geology - Abstract
International audience; Hydrocarbons were analyzed in sediments from the Congo River deep-sea fan, from the Congo River, and in sinking particles collected by sediment traps 40 m above the sediment. Studied sites encompassed three lobes of decreasing age of formation along the canyon: sites A, F and C and a another lobe system, disconnected from the active channel since 4 ka, Site E. Terrestrial long-chain odd n-alkanes were dominant in all sediments of the lobe system. Unsaturated terpenoids sourced by higher plants, such as gammacerene, lupene, ursene and oleanene, were also detected. At site C, characterized by high accumulation rates (10–20 cm yr−1), the organic matter spends less time in the oxic layer than at other sites and high phytadiene concentrations 10–17 μg gOC−1) evidenced recent terrestrial and phytoplanktonic remains reworked in anaerobic conditions. In these sediments, organic carbon-normalized concentrations of terrestrial alkanes and terpenoids were several fold higher than in the lobe sediments with lower accumulation rates (sites A and F), arguing for a more rapid degradation of terrestrial hydrocarbons than bulk organic carbon in the first steps of pre-diagenesis. Ample variations in the contributions of biomarkers from higher plants, ferns, bacteria and angiosperms, indicate an heterogeneous contribution of the soil and vegetation detritus delivered to the Congo lobe sediments. Lower concentrations in terrestrial hydrocarbons at site E, 45 km away from the active canyon, indicated that river particles are still admixed to the dominant marine organic matter. Diploptene and hop-7(21)-ene have a dual origin, from terrestrial and marine microorganisms. Scatter in their relationship to gammacerene argues for a contribution of marine microorganisms, in addition to soils-sourced microorganisms. The close distribution patterns of diploptene, hop-21-ene, hop-7(21)ene and neohop-13(18)-ene is in line with the hypothesis of sequential clay-catalyzed isomerisation of bacterial hopenes. Terrestrial biomarker accumulation fluxes at site C are one order of magnitude higher than vertical pelagic flux, demonstrating the magnitude of the inputs delivered through turbiditic transport in the submarine canyon. Crude oil contamination was evidenced at the disconnected site E (UCM, C21 to C26 tricyclic diterpanes, CPI) and, in smaller amounts, in some sediments from sites A and C. It may be related to marine crude oil extraction and transport. A short-chain mode of alkanes with an even predominance is evidenced in sediments of the lobe complex and likely sources, crude oil, microorganisms and ferns, are discussed.
- Published
- 2017
34. Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan
- Author
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Lucie Pastor, Carole Decker, Marie Morineaux, Alexis Khripounoff, Christophe Rabouille, Jean-Claude Caprais, M. Ain Baziz, Karine Olu, Lenaick Menot, Laboratoire Environnement Profond (LEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ANR-11-BS56-0030,CONGOLOBE,Transfert de carbone organique et fonctionnement des écosystèmes dans les lobes terminaux de l'éventail sous-marin du Congo(2011), Etudes des Ecosystèmes Profonds (EEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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0106 biological sciences ,010504 meteorology & atmospheric sciences ,Population ,Oceanography ,01 natural sciences ,Deep sea ,organic rich sediments ,Organic rich sediments ,14. Life underwater ,education ,[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography ,0105 earth and related environmental sciences ,Chemosynthesis ,education.field_of_study ,010604 marine biology & hydrobiology ,Pockmark ,Sediment ,Macrofaunal communities ,15. Life on land ,Cold seep ,Cold seeps ,Chemosynthesis-based ecosystems ,Angola Basin ,Benthic zone ,cold seeps ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,macrofaunal communities ,Geology - Abstract
International audience; Methane-rich fluids arising from organic matter diagenesis in deep sediment layers sustain chemosynthesis-based ecosystems along continental margins. This type of cold seep develops on pockmarks along the Congo margin, where fluids migrate from deep-buried paleo-channels of the Congo River, acting as reservoirs. Similar ecosystems based on shallow methane production occur in the terminal lobes of the present-day Congo deep-sea fan, which is supplied by huge quantities of primarily terrestrial material carried by turbiditic currents along the 800 km channel, and deposited at depths of up to nearly 5000 m. In this paper, we explore the effect of this carbon enrichment of deep-sea sediments on benthic macrofauna, along the prograding lobes fed by the current active channel, and on older lobes receiving less turbiditic inputs. Macrofaunal communities were sampled using either USNEL cores on the channel levees, or ROV blade cores in the chemosynthesis-based habitats patchily distributed in the active lobe complex. The exceptionally high organic content of the surface sediment in the active lobe complex was correlated with unusual densitiesof macrofauna for this depth, enhanced by a factor 7 to 8, compared with those of the older, abandoned lobe, whose sediment carbon content is still higher than in Angola Basin at same depth. Macrofaunal communities, dominated by cossurid polychaetes and tanaids were also more closely related to those colonizing low-flow cold seeps than those of typical deep-sea sediment. In reduced sediments, microbial mats and vesicomyid bivalve beds displayed macrofaunal community patterns that were similar to their cold-seep counterparts, with high densities, low diversity and dominance of sulfide-tolerant polychaetes and gastropods in the most sulfidic habitats. In addition, diversity was higher in vesicomyid bivalve beds, which appeared to bio-irrigate the upper sediment layers. High beta-diversity is underscored by the variability of geochemical gradients in vesicomyid assemblages, and by the vesicomyid population characteristics that vary in density, size and composition. By modifying the sediment geochemistry differently according to their morphology and physiology, the different vesicomyid species play an important role structuring macrofauna composition and vertical distribution. Dynamics of turbiditic deposits at a longer temporal scale (thousands of years) and their spatial distribution in the lobe area also resulted in high heterogeneity of the "cold-seep-like communities". Dynamics of chemosynthetic habitats and associated macrofauna in the active lobe area 2 Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. resembled those previously observed at the Regab pockmark along the Congo margin and rapid succession is expected to cope with high physical disturbance by frequent turbiditic events and huge sedimentation rates. Finally, we propose a model of the temporal evolution of these peculiar habitats and communities on longer timescales in response to changes in distributary channels within the lobe complex.
- Published
- 2017
35. Near-bottom biological and mineral particle flux in the Lucky Strike hydrothermal vent area (Mid-Atlantic Ridge)
- Author
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Khripounoff, Alexis, Comtet, Thierry, Vangriesheim, Annick, and Crassous, Philippe
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- 2000
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36. 'Total' sediment biomass and preliminary estimates of organic carbon residence time in deep-sea benthos
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Rowe, G., Sibuet, M., Deming, J., Khripounoff, A., Tietjen, J., Macko, S., and Theroux, R.
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- 1991
37. Different types of sediment gravity flows detected in the Var submarine canyon (northwestern Mediterranean Sea)
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R. Silva Jacinto, Philippe Crassous, Alexis Khripounoff, Bernard Dennielou, and N. Lo Bue
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Canyon ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Sediment ,Geology ,Submarine canyon ,Landslide ,Aquatic Science ,010502 geochemistry & geophysics ,01 natural sciences ,Current (stream) ,Current meter ,Mediterranean sea ,Oceanography ,Acoustic Doppler current profiler ,13. Climate action ,14. Life underwater ,0105 earth and related environmental sciences - Abstract
Current velocities and vertical sediment fluxes in the Var submarine canyon were assessed at three stations respectively at 800 m, 1200 m and 1800 m depth, using moorings deployed for 4 months during winter 2008-2009. During this period, we observed three major sediment gravity flows, all characterized by sudden increases in current velocity that lasted 2-5 h and by downward particle fluxes. Each gravity flow, described using a high frequency current meter and two Acoustic Doppler Current Profiler (75 and 300 kHz ADCP) showed distinctive features. The first event, triggered during a flood of the Var River, was determined to be a hyperpycnal current with a large vertical extent (>100 m high) and relatively low velocity (40 cm s(-1)). The second event, observed after a Var River flood, was more energetic with a maximum horizontal current peak of 60 cm s(-1) with a low vertical extent (30 m high). This event was considered to be a turbidity landslide. The third was the result of a local canyon wall failure. It was characterized by a speed of >85 cm s(-1). These peaks of current speed were associated with large clouds of material that transported sediment along the canyon and reached up to 200 g m(-2) d(-1) of sediment (>1 g m(-2) d(-1) of organic carbon). Our measurements in the Var canyon show the important role of gravity flows transporting particulate matter to the deep-sea floor. These large inputs of sediment and organic carbon may have a significant impact on deep-sea carbon storage in the Mediterranean Sea. (C) 2012 Elsevier Ltd. All rights reserved.
- Published
- 2012
38. A new species ofExrima,synonymy of four species ofAphotopontius, StygiopontiusandRhogobius, and record of first copepodid stage of Dirivultidae (Copepoda: Siphonostomatoida) from deep-sea hydrothermal vents of the East Pacific Rise (13°N)
- Author
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Alexis Khripounoff, Frank D. Ferrari, Michel Segonzac, Danielle Defaye, Viatcheslav N. Ivanenko, and Jozée Sarrazin
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Oceanography ,Siphonostomatoida ,Genus ,Synonym ,Operculum (bryozoa) ,Dolichopus ,Zoology ,Key (lock) ,Seta ,Aquatic Science ,Biology ,biology.organism_classification ,Hydrothermal vent - Abstract
Females of the new speciesExrima walterisp. nov. were found in sediment trap samples deployed over different sites of the East Pacific Rise (13°N) at 2600 m depth. Four traps were deposited during the HOPE99 cruise (1999) and recovered during the AMISTAD (1999) cruise on the research vessel ‘L'Atalante’. The new species is distinguished from congeners,E. singulaHumes, 1987 andE. dolichopusHumes, 1987, by the following derived characters: first somite of the urosome with 3 (one dorsal and two lateral) stout conical extensions; distal endopodal segment on the swimming leg 4 broad. In addition, many specimens of copepodids I and lecithotrophic nauplii, identified as belonging to Dirivultidae gen. sp., were found in the samples of all sediment traps. This is the first record of copepodids I and of a nauplius of dirivultids from the Pacific Ocean. Study of type and additional material collected during different Ifremer cruises at different vent sites (HERO91, EXOMAR, PHARE and MoMARETO) required synonymy of four species ofAphotopontiusHumes, 1987,StygiopontiusHumes, 1987 andRhogobiusHumes, 1987.Aphotopontius rapunculusHumes and Segonzac, 1998 is transferred to the genusRhogobiusbecause it possesses all presumed derived attributes of this genus: last abdominal somite with lobes at sides of anal operculum; second segment of antennal endopod elongate and slender. A new study of the type material suggests that:Aphotopontius temperatusHumes, 1997 is a synonym ofA. atlanteusHumes, 1996;Stygiopontius lumigerHumes, 1989 is a synonym ofS. sentiferHumes, 1987 whileS. bulbisetigerHumes, 1996 is a synonym ofS. pectinatusHumes, 1987. Females of the three synonymized species were found to be sub-adult females at copepodid V. Leg 6 on these specimens is one seta located dorsolaterally on the posterior part of the genital somite. This position for leg 6 is unknown for copepodid V of other siphonostomatoids whose leg 6 is located ventrally at copepodid V; the dorsolateral position is presumed derived and shared by the dirivultid generaAphotopontiusHumes, 1987 andStygiopontiusHumes, 1987. A new key to the Dirivultidae genera is presented.
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- 2011
39. Spatial heterogeneity of macrofaunal communities in and near a giant pockmark area in the deep Gulf of Guinea
- Author
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Philippe Crassous, Myriam Sibuet, Jean-Claude Caprais, Alexis Khripounoff, Joëlle Galéron, Karine Olu, and Lenaick Menot
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0106 biological sciences ,Chemosynthesis ,Polychaete ,010504 meteorology & atmospheric sciences ,Ecology ,biology ,010604 marine biology & hydrobiology ,Pockmark ,Beta diversity ,15. Life on land ,Aquatic Science ,biology.organism_classification ,01 natural sciences ,Cold seep ,Petroleum seep ,Oceanography ,Alpha diversity ,14. Life underwater ,Bioturbation ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences - Abstract
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 the border of the pockmark area, the chemosynthetic ecosystem had no significant influence on macrofaunal communities beyond the edge of the giant pockmark. In seep sediments, the macrofauna had higher densities, reaching over 22,000 ind·m−2, but lower taxonomic richness than in background sediments. The polychaete assemblages associated with siboglinid tubeworms differed in their composition and vertical distribution from communities associated with vesicomyids or found at the border between vesicomyids and mytilids. The siboglinid habitat was dominated by surface-feeders (ampharetids) or small carnivores (dorvilleids, hesionids and syllids) concentrated in the top sediment layer, while the vesicomyid beds were dominated by deep-dwelling, subsurface feeders (capitellids and cossurids). This pattern may be related to bioturbation by the vesicomyids that allows an oxygenation of surface sediments while deepening down and enhancing the anaerobic oxidation of methane. Although alpha diversity of polychaete families is low in seep sediments, the variability of faunal assemblages and potentially high level of speciation in cold-seep environments point to high beta diversity. Comparable numbers of polychaete families coexist in a quarter square meter of seep or non-seep sediments, although the number of ecological niches that were sampled might be higher at seeps. Further integrative and comparative studies of the diversity and functioning of seep and non-seep communities would certainly provide clues to understanding both ecosystems and their interactions.
- Published
- 2009
40. High frequency of sediment gravity flow events in the Var submarine canyon (Mediterranean Sea)
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Philippe Crassous, Alexis Khripounoff, Joel Etoubleau, and Annick Vangriesheim
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Gravity (chemistry) ,Turbidity current ,010504 meteorology & atmospheric sciences ,Particle flux ,Submarine canyon ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Hyperpycnal flow ,Mediterranean sea ,Geochemistry and Petrology ,Var canyon ,Sediment gravity flow ,14. Life underwater ,Geomorphology ,West Mediterranean Sea ,0105 earth and related environmental sciences ,Canyon ,geography ,geography.geographical_feature_category ,Terrigenous sediment ,Sediment ,Geology ,13. Climate action - Abstract
This study aimed to analyze the role river floods play in triggering gravity flows and to investigate the role of submarine canyon systems as a conduit for terrigenous material to the deep sea. Two years of measurements in the Var canyon at depths ranging from 1200 m to 2350 m indicate that six floods of the Var River triggered hyperpycnal flows, an important mechanism for transporting particulate matter to the deep-sea floor. These sediment gravity flows were characterized by a sudden increase of current velocity that lasted 8 to 22 h and by downward particle fluxes that reached up to 600 g m(-2)d(-1) of particles and 3.1 g m(-2)d(-1) in terms of organic carbon. These large inputs of sediment and organic carbon may have a significant impact on deep-sea ecosystems and carbon storage in the Mediterranean Sea.
- Published
- 2009
41. The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling
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Rabouille, C., primary, Olu, K., additional, Baudin, F., additional, Khripounoff, A., additional, Dennielou, B., additional, Arnaud-Haond, S., additional, Babonneau, N., additional, Bayle, C., additional, Beckler, J., additional, Bessette, S., additional, Bombled, B., additional, Bourgeois, S., additional, Brandily, C., additional, Caprais, J.C., additional, Cathalot, C., additional, Charlier, K., additional, Corvaisier, R., additional, Croguennec, C., additional, Cruaud, P., additional, Decker, C., additional, Droz, L., additional, Gayet, N., additional, Godfroy, A., additional, Hourdez, S., additional, Le Bruchec, J., additional, Saout, J., additional, Le Saout, M., additional, Lesongeur, F., additional, Martinez, P., additional, Mejanelle, L., additional, Michalopoulos, P., additional, Mouchel, O., additional, Noel, P., additional, Pastor, L., additional, Picot, M., additional, Pignet, P., additional, Pozzato, L., additional, Pruski, A.M., additional, Rabiller, M., additional, Raimonet, M., additional, Ragueneau, O., additional, Reyss, J.L., additional, Rodier, P., additional, Ruesch, B., additional, Ruffine, L., additional, Savignac, F., additional, Senyarich, C., additional, Schnyder, J., additional, Sen, A., additional, Stetten, E., additional, Sun, Ming Yi, additional, Taillefert, M., additional, Teixeira, S., additional, Tisnerat-Laborde, N., additional, Toffin, L., additional, Tourolle, J., additional, Toussaint, F., additional, Vétion, G., additional, Jouanneau, J.M., additional, and Bez, M., additional
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- 2017
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42. Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan
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Olu, K., primary, Decker, C., additional, Pastor, L., additional, Caprais, J.-C., additional, Khripounoff, A., additional, Morineaux, M., additional, Ain Baziz, M., additional, Menot, L., additional, and Rabouille, C., additional
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- 2017
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43. Respiration of bivalves from three different deep-sea areas: Cold seeps, hydrothermal vents and organic carbon-rich sediments
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Khripounoff, A., primary, Caprais, J.C., additional, Decker, C., additional, Le Bruchec, J., additional, Noel, P., additional, and Husson, B., additional
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- 2017
- Full Text
- View/download PDF
44. Aliphatic hydrocarbons and triterpenes of the Congo deep-sea fan
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Méjanelle, Laurence, primary, Rivière, Béatrice, additional, Pinturier, Laurence, additional, Khripounoff, Alexis, additional, Baudin, François, additional, and Dachs, Jordi, additional
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- 2017
- Full Text
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45. Geochemical and biological recovery of the disturbed seafloor in polymetallic nodule fields of the Clipperton-Clarion Fracture Zone (CCFZ) at 5,000-m depth
- Author
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Joel Etoubleau, Philippe Crassous, Jean-Claude Caprais, and Alexis Khripounoff
- Subjects
Nodule (geology) ,Disturbance (geology) ,Sediment ,Soil science ,Fracture zone ,Aquatic Science ,engineering.material ,Oceanography ,Seafloor spreading ,Benthic zone ,Sediment–water interface ,engineering ,Seawater ,Geology - Abstract
Environmental data were obtained on the nodule fields of the Clipperton-Clarion Fracture Zone at 5,000-m depth in June 2004 during the Nodinaut cruise. The long-term effects of physical disturbance made by a dredge 26 yr ago on the sediment were investigated. We focused our study on its track, which is still visible on the bottom. The first major consequence of the passage of this equipment was to remove 4 cm 6 0.5 cm of superficial sediment. The physical and chemical properties of this disturbed sediment sampled in the track did not change significantly over time and has not shown any recovery since the disturbance. However, an exception was observed for depth variations of manganese concentration in the sediment, which were similar in the track to those in the surrounding undisturbed sediment and can be explained by the diffusion over time of oxygen from the sea water. On the other hand, the biological activity measured in the track with the respirometer RAP2 carried by the submersible Nautile did not differ from the unperturbed site, which suggests that the benthic fauna has completely recovered, as have nutrient fluxes at the water–sediment interface.
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- 2006
46. Evaluation of a lifetime-based optode to measure oxygen in aquatic systems
- Author
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Anders Tengberg, Olivier Brocandel, Alexis Khripounoff, Tony Arnerich, Jens Schimanski, Christian Huber, David Hebert, Jostein Hovdenes, Henrik Johan Andersson, Arne Körtzinger, Francisco Rey, Stefan Sommer, Christer Rönning, Robert J. Diaz, and Achim Stangelmayer
- Subjects
0106 biological sciences ,Measure (data warehouse) ,010504 meteorology & atmospheric sciences ,010604 marine biology & hydrobiology ,Aquatic ecosystem ,chemistry.chemical_element ,Ocean Engineering ,Soil science ,01 natural sciences ,Oxygen ,6. Clean water ,Oxygen monitoring ,chemistry ,Environmental chemistry ,Environmental science ,14. Life underwater ,Optode ,Biological sciences ,0105 earth and related environmental sciences - Abstract
In this article, we evaluate the performance of a commercially available lifetime-based optode and compare it with data obtained by other methods. We performed a set of 10 different tests, including targeted laboratory evaluations and field studies, covering a wide range of situations from shallow coastal waters and wastewater treatment plants to abyssal depths. Our principal conclusion is that, owing to high accuracy (± 2 µM), long-term stability (more than 20 months), lack of pressure hysteresis, and limited cross-sensitivity, this method is overall more suitable for oxygen monitoring than other methods.
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- 2006
47. Rare earth elements and neodymium isotopes in sedimentary organic matter
- Author
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Sylvain Bermell, Sandrine Cheron, Samuel Toucanne, Alexis Khripounoff, Yoan Germain, Emmanuel Ponzevera, Joel Etoubleau, Marie Laure Rouget, Claire Bollinger, Germain Bayon, Nicolas Freslon, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), UMS 3113, Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), and IFREMER
- Subjects
chemistry.chemical_classification ,010504 meteorology & atmospheric sciences ,Terrigenous sediment ,[SDE.MCG]Environmental Sciences/Global Changes ,Geochemistry ,Sediment ,010502 geochemistry & geophysics ,01 natural sciences ,Diagenesis ,Sedimentary depositional environment ,chemistry.chemical_compound ,chemistry ,13. Climate action ,Geochemistry and Petrology ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Carbonate ,Sedimentary organic matter ,Sedimentary rock ,Organic matter ,14. Life underwater ,Geology ,0105 earth and related environmental sciences - Abstract
We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2–0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display eNd values that typically range between the eNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter (inferred from the analysis of local surface seawater). A notable exception is the case of organic matter (OM) fractions leached from cold seep sediment samples, which sometimes exhibit eNd values markedly different from both terrigenous and surface seawater signatures. This suggests that a significant fraction of organic compounds in these sediments may be derived from chemosynthetic processes, recycling pore water REE characterized by a distinct isotopic composition. Overall, our results confirm that organic matter probably plays an important role in the oceanic REE budget, through direct scavenging and remineralization within the water column. Both the high REE abundances and the shape of shale-normalized patterns for leached SOM also suggest that OM degradation in sub-surface marine sediments during early diagenesis could control, to a large extent, the distribution of REE in pore waters. Benthic fluxes of organic-bound REE could hence substantially contribute to the exchange processes between particulates and seawater that take place at ocean margins. Neodymium isotopes could provide useful information for tracing the origin (terrestrial versus marine) and geographical provenance of organic matter, with potential applications in paleoceanography. In particular, future studies should further investigate the potential of Nd isotopes in organic compounds preserved in sedimentary records for reconstructing past variations of surface ocean circulation.
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- 2014
48. Hydrothermal plume-particle fluxes at 13 degree N on the East Pacific Rise
- Author
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German, C.R., Colley, S., Palmer, M.R., Khripounoff, A., and Klinkhammer, G.P.
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Pacific Ocean -- Research ,Sediments (Geology) -- Research ,Plumes (Fluid dynamics) -- Research ,Earth sciences - Abstract
The geochemical flux to sediment traps assembled close to the Totem vent site, 13 degree N East Pacific Rise is examined. An important emphasis is to investigate what proportion of this settling flux procures from direct co-precipitation of vent-fluid material as polymetallic sulphides, and what proportion is in the form of Fe oxyhydroxide material, which co-precipitates vent-fluid metals as well as can search dissolved material from seawater.
- Published
- 2002
49. Intercalibration of benthic flux chambers
- Author
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F. de Bovee, Per O. J. Hall, Ronnie N. Glud, Bengt Lindén, Gilbert T. Rowe, Jens-Uwe Friemann, Peter H. Santschi, Allan H. Devol, P. de Wilde, Anders Tengberg, B. Carlsson, Gerard C.A. Duineveld, Ursula Witte, S Ceradini, J. Leather, O Styrenius, Peter Linke, U Andersson, Alexis Khripounoff, Lars Chresten Lund-Hansen, and G Boland
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,Chemistry ,010604 marine biology & hydrobiology ,Mixing (process engineering) ,Sediment ,Mineralogy ,General Chemistry ,Oceanography ,Boundary layer thickness ,01 natural sciences ,6. Clean water ,Silicate ,Boundary layer ,Pore water pressure ,chemistry.chemical_compound ,Flux (metallurgy) ,Sediment–water interface ,Environmental Chemistry ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
We have compared 14 different sediment incubation chambers, most of them were used on bottom landers. Measurements of mixing time, pressure gradients at the bottom and Diffusive Boundary Layer thickness (DBL) were used to describe the hydrodynamic properties of the chambers and sediment–water solute fluxes of silicate (34 replicates) and oxygen (23 replicates) during three subsequently repeated incubation experiments on a homogenized, macrofauna-free sediment. The silicate fluxes ranged from 0.24 to 1.01 mmol m−2 day−1 and the oxygen fluxes from 9.3 to 22.6 mmol m−2 day−1. There was no statistically significant correlation between measured fluxes and the chamber design or between measured fluxes and hydrodynamic settings suggesting that type of chamber was not important in these flux measurements. For verification of sediment homogeneity, 61 samples of meiofauna were taken and identified to major taxa. In addition, 13 sediment cores were collected, sectioned into 5–10-mm slices and separated into pore water and solid phase. The pore water profiles of dissolved silicate were used to calculate diffusive fluxes of silicate. These fluxes ranged from 0.63 to 0.87 mmol m−2 day−1. All of the collected sediment parameters indicated that the sediment homogenization process had been satisfactorily accomplished. Hydrodynamic variations inside and between chambers are a reflection of the chamber design and the stirring device. In general, pump stirrers with diffusers give a more even distribution of bottom currents and DBL thicknesses than paddle wheel-type stirrers. Most chambers display no or low static differential pressures when the water is mixed at rates of normal use. Consequently, there is a low risk of creating stirrer induced pressure effects on the measured fluxes. Centrally placed stirrers are preferable to off-center placed stirrers which are more difficult to map and do not seem to give any hydrodynamic advantages. A vertically rotating stirrer gives about five times lower static differential pressures at the same stirring speed as the same stirrer mounted horizontally. If the aim is to simulate or mimic resuspension at high flow velocities, it cannot be satisfactorily done in a chamber using a horizontal (standing) rotating impeller (as is the case for most chambers in use) due to the creation of unnatural conditions, i.e. large static differential pressures and pre-mature resuspension at certain locations in the chamber.
- Published
- 2005
50. Hydrothermal plume-particle fluxes at 13°N on the East Pacific Rise
- Author
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A Khripounoff, S Colley, M.R Palmer, Christopher R. German, and Gary P. Klinkhammer
- Subjects
Settling ,Sediment trap ,Panache ,Mineralogy ,Seawater ,Aquatic Science ,Oceanography ,Scavenging ,Geology ,Hydrothermal circulation ,Plume ,Hydrothermal vent - Abstract
We have investigated the geochemical flux to sediment traps deployed close to the Totem vent site, 13°N EPR. An important emphasis has been to investigate what proportion of this settling flux derives from direct co-precipitation of vent-fluid material as polymetallic sulphides and what proportion is in the form of Fe oxyhydroxide material which not only co-precipitates vent-fluid metals but can also scavenge dissolved material from seawater. Mass fluxes and major element compositions (Fe, S, Al, Mn, CaCO3 and Corg) for our near vent samples compare well with results from previously reported Pacific hydrothermal sediment trap studies, both at this site and on the Endeavour Ridge. Our samples record large fluxes of Cu, Zn and Pb, as well as V and P, all of which are in excess over typical open-ocean trap values. If P and V are transported to the traps as sinking Fe-oxyhydroxide material from the neutrally buoyant plume, we calculate that 10–20% of the Fe entering the near vent traps occurs as oxidised material with the remaining 80–90% being supplied by polymetallic sulphides. Shale-normalised REE distribution patterns for near-vent trap samples are similar to those for local vent fluids and sulphidic sediments. Detailed mass balance calculations, however, reveal evidence for additional input from hydrothermal Fe-oxyhydroxide material with a scavenged REE composition that is less "evolved" than that reported for local neutrally buoyant plume particles. U fluxes into the near vent traps are high and consistent with uptake by sulphides. 210Pb fluxes are also high and appear dominated by co-precipitation direct from vent-fluids as Pb-sulphides. In contrast, Fe-oxyhydroxide scavenging from seawater can account for the entire 230Th and 232Th fluxes reported. If the scavenging processes identified here were similarly active in neutrally buoyant plumes, we would predict hydrothermal scavenging to impact ocean biogeochemical cycles significantly, e.g. causing removal of ca. 10% of the dissolved 230Th production from the deep water column, out to a distance of ca. 10–100 km off-axis, along the entire 60,000 km global ridge-crest.
- Published
- 2002
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