Consulta: creatorFacets:"Olu, Karine"
Registros recuperados: 58
Data/hora: 16/06/2024 17:31:19

The vesicomyid bivalve habitat at cold seeps supports heterogeneous and dynamic macrofaunal assemblages
Provedor de dados: 5
Autores: Guillon, Erwan; Menot, Lenaick; Decker, Carole; Krylova, Elena; Olu, Karine.
The high biodiversity found at cold seeps, despite elevated concentrations of methane and hydrogen sulfide, is attributed to multiple sources of habitat heterogeneity. In addition to geological and geochemical processes, biogenic habitats formed by large symbiont-bearing taxa, such as bivalves and siboglinid tubeworms, or by microbial mats drive the biodiversity of small-sized fauna. However, because these habitat-forming species also depend on geochemical gradients, the respective influence of abiotic and biotic factors in structuring associated macrofaunal communities is often unresolved. The giant pockmark Regab located at 3200 m depth on the Congo margin is characterized by different fluid-flow regimes, providing a mosaic of the most common biogenic...
Tipo: Text
Palavras-chave: Cold-seep; Macrofauna; Diversity; Dynamics; Vesicomyid clams; Gulf of Guinea.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00361/47210/47165.pdf

EXtreme ecosystem studies in the deep OCEan: Technological Developments. EXOCET/D
Provedor de dados: 5
Autores: Sarradin, Pierre-marie; Sarrazin, Jozee; Cadiou, Jean-francois; Olu, Karine; Desbruyeres, Damien; Rigaud, Vincent; Drogou, Jean-francois; Lecornu, Fabrice; Rolin, Jean-francois; Vuillemin, Renaud; Cambon-bonavita, Marie-anne; Sauter, E; Von Juterzenka, K; Boetius, A; Santos, Rs; Colaco, Ana; Pascoal, A; Oliveira, Paulo; Shillito, Bruce; Zal, F; Schultz, A; Taylor, P; Lane, D; Loke, Rob; Du Buf, H; Waldmann, C; Cormack, A; Sanfilippo, L; Masson, M.
The general objective of EXOCET/D is to develop, implement and test specific instruments aimed at exploring, describing, quantifying and monitoring biodiversity in deep-sea fragmented habitats as well as at identifying links between community structure and environmental dynamics. Onboard experimental devices will complement the approach, enabling experiments on species physiology. The EXOCET/D working fields include: video and acoustic imagery, in situ analysis of physico-chemical factors, quantitative sampling of macroand micro-organisms, in vivo experiments, integration of multidisciplinary data, implementation on European deep-submersibles and a final phase of technical and scientific validation
Tipo: Text
Palavras-chave: Deep sea; Ecosystem; Imagery; In situ analysis; Faunal sampling; Submersibles; Observatory.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/2007/publication-3600.pdf

Early diagenesis in the sediments of the Congo deep-sea fan dominated by massive terrigenous deposits: Part III – Sulfate- and methane- based microbial processes
Provedor de dados: 5
Autores: Pastor, Lucie; Toffin, Laurent; Decker, Carole; Olu, Karine; Cathalot, Cecile; Lesongeur, Francoise; Caprais, Jean-claude; Bessette, Sandrine; Brandily, Christophe; Taillefert, M.; Rabouille, C.
Geochemical profiles (SO42-, H2S, CH4, δ13CH4) and phylogenetic diversity of Archaea and Bacteria from two oceanographic cruises dedicated to the lobes sediments of the Congo deep-sea fan are presented in this paper. In this area, organic-rich turbidites reach 5000 m and allow the establishment of patchy cold-seep-like habitats including microbial mats, reduced sediments, and vesicomyid bivalves assemblages. These bivalves live in endosymbiosis with sulfur-oxidizing bacteria and use sulfides to perform chemosynthesis. In these habitats, unlike classical abyssal sediments, anoxic processes are dominant. Total oxygen uptake fluxes and methane fluxes measured with benthic chambers are in the same range as those of active cold-seep environments, and oxygen is...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00376/48767/49164.pdf

First observations of deep-sea coral reefs along the Angola margin
Provedor de dados: 5
Autores: Le Guilloux, E.; Olu, Karine; Bourillet, Jean-francois; Savoye, Bruno; Iglesias, S. P.; Sibuet, Myriam.
The West African continental slope is an important theatre for geological survey prospecting and drilling for hydrocarbons but little is known about local deep-sea biological communities at these depths. While shallow-water reefs are common and well-known features in the tropics, only few records of deep-water corals exist at low latitudes, and most of them have been reported by historical oceanographic cruises undertaking circum-navigations of the world. This study, based on a multi-disciplinary approach, presents a description of newly discovered deep-water coral reef communities along the Angola margin. Data from ROV, multibeam bathymetry, side-scan sonar and seismics from a deep-towed acoustic system (SAR) were used to describe the morphology of the...
Tipo: Text
Palavras-chave: Lucinids; Habitat mapping; ROV; Lophelia pertusa; Deep sea corals; Angola margin.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7403.pdf

Spatial heterogeneity of macrofaunal communities in and near a giant pockmark area in the deep Gulf of Guinea
Provedor de dados: 5
Autores: Menot, Lenaick; Galeron, Joelle; Olu, Karine; Caprais, Jean-claude; Crassous, Philippe; Khripounoff, Alexis; Sibuet, Myriam.
The structure and familial-level composition of macrofaunal communities were examined within and at distance from the giant pockmark Regab in the Southern Gulf of Guinea, at 3200 m depth. The two main questions addressed in this study were (i) does habitat partitioning by large symbiont-bearing taxa. influence macrofaunal assemblages and their environment? and (ii) to what extent does the chemosynthesis-based ecosystem influence the structure and the composition of nearby macrobenthic communities? Along two radials, at sites from 250 to 1000 m away from the active centre of the cold seep, the abundance and composition of the macrofauna were typical of a deep-sea community at that depth. Except for a few cores sampled in or near dead vesicomyid fields at...
Tipo: Text
Palavras-chave: Cold seep; Diversity; Gulf of Guinea; Habitat heterogeneity; Macrofauna; Open slope; Siboglinid tubeworms; Vesicomyid clams.
Ano: 2010
URL: https://archimer.ifremer.fr/doc/00002/11282/8099.pdf

Habitat heterogeneity influences cold-seep macrofaunal communities within and among seeps along the Norwegian margin. Part 1: macrofaunal community structure
Provedor de dados: 5
Autores: Decker, Carole; Morineaux, Marie; Van Gaever, Saskia; Caprais, Jean-claude; Lichtschlag, Anna; Gauthier, Olivier; Andersen, Ann C.; Olu, Karine.
Håkon Mosby mud volcano (HMMV) is one of the most active and most studied seep sites in European waters. Many authors have described its thermal activity, dynamic of mud flows, and geochemical and microbial processes. It is characterised by a concentric zonation of successive biogenic habitats related to an activity and geochemical gradient from its centre to its periphery. Around the central area covered by mud flows, white and grey microbial mats occur among areas of bare sediment, whereas siboglinid tubeworm fields of Sclerolinum contortum and/or Oligobrachia haakonmosbiensis colonise the peripheral areas. The meiofaunal community is known to be structured among habitats, but the macrofauna has rarely been investigated and has never been sampled in...
Tipo: Text
Palavras-chave: Cold-seep; Community structure; Macrofauna; Norwegian margin; Polychaeta.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00074/18517/16130.pdf

Ecophysiological differences between vesicomyid species and metabolic capabilities of their symbionts influence distribution patterns of the deep‐sea clams
Provedor de dados: 5
Autores: Cruaud, Perrine; Decker, Carole; Olu, Karine; Arnaud-haond, Sophie; Papot, Claire; Le Baut, Jocelyn; Vigneron, Adrien; Khripounoff, Alexis; Gayet, Nicolas; Cathalot, Cecile; Caprais, Jean-claude; Pignet, Patricia; Godfroy, Anne; Cambon Bonavita, Marie-anne.
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...
Tipo: Text
Palavras-chave: Deep-sea ecosystems; Guaymas Basin; Marine ecology; Pliocardinae bivalve; Sulfur storage; Vesicomyid movements.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00493/60426/64028.pdf

Trophic relationships in a deep Mediterranean cold-water coral bank (Santa Maria di Leuca, Ionian Sea)
Provedor de dados: 5
Autores: Carlier, A.; Le Guilloux, E.; Olu, Karine; Sarrazin, Jozee; Mastrototaro, F.; Taviani, M.; Clavier, J.
Cold-water corals (CWC) are frequently reported from deep sites with locally accelerated currents that enhance seabed food particle supply. Moreover, zooplankton likely account for ecologically important prey items, but their contribution to CWC diet remains unquantified. We investigated the benthic food web structure of the recently discovered Santa Maria di Leuca (SML) CWC province (300 to 1100 m depth) located in the oligotrophic northern Ionian Sea. We analyzed stable isotopes (delta C-13 and delta N-15) of the main consumers (including ubiquitous CWC species) exhibiting different feeding strategies, zooplankton, suspended particulate organic matter (POM) and sedimented organic matter (SOM). Zooplankton and POM were collected 3 m above the coral...
Tipo: Text
Palavras-chave: Particulate organic matter; Zooplankton; Stable isotopes; Food web; Mediterranean Sea; Benthic community; Cold water corals.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7450.pdf

Energy transfer in the Congo deep-sea fan: from terrestrially-derived organic matter to chemosynthetic food webs
Provedor de dados: 5
Autores: Pruski, A. M.; Decker, Carole; Stetten, E.; Vetion, G.; Martinez, P.; Charlier, K.; Senyarich, C.; Olu, Karine.
Large amounts of recent terrestrial organic matter (OM) from the African continent are delivered to the abyssal plain by turbidity currents and accumulate in the Congo deep-sea fan. In the recent lobe complex, large clusters of vesicomyid bivalves are found all along the active channel in areas of reduced sediment. These soft-sediment communities resemble those fuelled by chemoautotrophy in cold-seep settings. The aim of this study was to elucidate feeding strategies in these macrofaunal assemblages as part of a greater effort to understand the link between the inputs of terrestrially-derived OM and the chemosynthetic habitats. The biochemical composition of the sedimentary OM was first analysed in order to evaluate how nutritious the available particulate...
Tipo: Text
Palavras-chave: Congo deep-sea fan; Food webs; Vesicomyid bivalves; Chemoautotrophy; Isotopic signatures; Fatty acid biomarkers.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00385/49686/50216.pdf

Eruption of a deep-sea mud volcano triggers rapid sediment movement
Provedor de dados: 5
Autores: Feseker, Tomas; Boetius, Antje; Wenzhofer, Frank; Blandin, Jerome; Olu, Karine; Yoerger, Dana R.; Camilli, Richard; German, Christopher R.; De Beer, Dirk.
Submarine mud volcanoes are important sources of methane to the water column. However, the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady-state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Hakon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the...
Tipo: Text
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00245/35601/34137.pdf

Biogeography and Potential Exchanges Among the Atlantic Equatorial Belt Cold-Seep Faunas
Provedor de dados: 5
Autores: Olu, Karine; Cordes, Erik E.; Fisher, Charles R.; Brooks, James M.; Sibuet, Myriam; Desbruyeres, Daniel.
Like hydrothermal vents along oceanic ridges, cold seeps are patchy and isolated ecosystems along continental margins, extending from bathyal to abyssal depths. The Atlantic Equatorial Belt (AEB), from the Gulf of Mexico to the Gulf of Guinea, was one focus of the Census of Marine Life ChEss (Chemosynthetic Ecosystems) program to study biogeography of seep and vent fauna. We present a review and analysis of collections from five seep regions along the AEB: the Gulf of Mexico where extensive faunal sampling has been conducted from 400 to 3300m, the Barbados accretionary prism, the Blake ridge diapir, and in the Eastern Atlantic from the Congo and Gabon margins and the recently explored Nigeria margin. Of the 72 taxa identified at the species level, a total...
Tipo: Text
Palavras-chave: Gulf of mexico; Barbados accretionary prism; Mussel bathymodiolus childressi; Hydrothermal vent communities; Deep sea vent; Spatial distribution; Family veiscomyidae; Dispersal barriers; Hydrocarbon seeps; Species diversity.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12207/8975.pdf

Deep-Sea Nematodes of the Mozambique Channel: Evidence of Random Community Assembly Dynamics in Seep Sediments
Provedor de dados: 5
Autores: Macheriotou, Lara; Rigaux, Annelien; Olu, Karine; Zeppilli, Daniela; Derycke, Sofie; Vanreusel, Ann.
Cold seeps occur globally in areas where gases escape from the seafloor, occasionally resulting in the formation of topographic depressions (pockmarks), characterised by unique physicochemical conditions such as anoxic and sulphuric sediments. Free-living marine nematodes tend to dominate the meiofaunal component in such environments, often occurring at extremely high densities and low richness; the mechanisms defining community assembly in areas of fluid seepage, however, have received little attention. Here we focus on a low-activity pockmark at 789 m in the Mozambique Channel (MC). We assessed the diversity, co-occurrence patterns and phylogenetic community structure of nematodes at this bathyal site to that of a nearby reference area as well as abyssal...
Tipo: Text
Palavras-chave: Cold seeps; Nematoda; Metabarcoding; Community structure; Phylogenetic community structure.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00679/79080/81524.pdf

The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling
Provedor de dados: 5
Autores: Rabouille, C.; Olu, Karine; Baudin, F.; Khripounoff, Alexis; Dennielou, Bernard; Arnaud-haond, Sophie; Babonneau, Nathalie; Bayle, Christophe; Beckler, J.; Bessette, Sandrine; Bombled, B.; Bourgeois, S.; Brandily, Christophe; Caprais, Jean-claude; Cathalot, Cecile; Charlier, K.; Corvaisier, R.; Croguennec, Chantal; Cruaud, Perrine; Decker, Carole; Droz, L.; Gayet, Nicolas; Godfroy, Anne; Hourdez, S.; Le Bruchec, J.; Saout, Johan; Le Saout, Marie-helene; Lesongeur, Francoise; Martinez, P.; Mejanelle, L.; Michalopoulos, P.; Mouchel, Olivier; Noel, Philippe; Pastor, Lucie; Picot, M.; Pignet, Patricia; Pozzato, L.; Pruski, A. M.; Rabiller, Manuella; Raimonet, M.; Ragueneau, O.; Reyss, J. L.; Rodier, Philippe; Ruesch, Blandine; Ruffine, Livio; Savignac, F.; Senyarich, C.; Schnyder, J.; Sen, Arunima; Stetten, E.; Sun, Ming Yi; Taillefert, M.; Teixeira, S.; Tisnerat-laborde, N.; Toffin, Laurent; Tourolle, Julie; Toussaint, F.; Vetion, G.; Jouanneau, J. M.; Bez, M.
The presently active region of the Congo deep-sea fan (around 330 000 km2), called the terminal lobes or lobe complex, covers an area of 2500 km2 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...
Tipo: Text
Palavras-chave: Chemosynthetic habitats; Congo deep-sea fan; Fine sediment; Sedimentation rate; Seafloor morphology; Turbidite; Vesicomyidae.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00335/44580/44298.pdf

Aspects on gametogenesis, fertilization and embryogenesis of two deep-sea polychaetes from Eastern Atlantic cold seeps
Provedor de dados: 5
Autores: Gaudron, S. M.; Hourdez, S.; Olu, Karine.
We investigated two gonochoristic species of annelid polychaetes (one siboglinid and one polynoid) from cold seeps that ranged from 525 m to 3300 m in depth (Guiness, Worm Hole and Regab pockmarks) on the Gabon and Congo continental margins (Gulf of Guinea). Different aspects of gametogenesis (oocyte diameter, presence of ovisac, spermatozoa shape, and fecundity), fertilization (in vitro fertilization experiments: IVF) and embryogenesis (cleavage rate) were studied. The sampled siboglinid was a new species of Lamellibrachia and the second population of this genus in the Eastern Atlantic. Mean oocyte diameter was about 100 µm and fully-grown primary oocytes were stored in an ovisac, as in other studied siboglinids. The presence of a single spermatozoon was...
Tipo: Text
Palavras-chave: Branchipolynoe; Cold seeps; Dispersal; Lamellibrachia; Polynoid; Reproduction; Siboglinid.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00405/51644/52192.pdf

Heterogeneous energetic pathways and carbon sources on deep eastern Mediterranean cold seep communities
Provedor de dados: 5
Autores: Carlier, Antoine; Ritt, Benedicte; Rodrigues, Clara F.; Sarrazin, Jozee; Olu, Karine; Grall, Jacques; Clavier, Jacques.
Cold seep communities in the Mediterranean Sea have only been discovered two decades ago, and their trophic ecology has been the subject of very few studies. We investigated the benthic food web of two deep chemosynthesis-based ecosystems on the Napoli and Amsterdam mud volcanoes (MVs) in the eastern Mediterranean Sea (similar to 2,000 m depth). Seeping methane has been detected at the surface of both MVs during pioneering cruises and has been hypothesised to be assimilated by benthic fauna as observed in other oceans' margins. Given the extreme oligotrophic character of the eastern Mediterranean Sea, we a priori expected that chemosynthetic food sources, especially methane-derived carbon (MDC), played a major trophic role in these deep seep communities...
Tipo: Text
Palavras-chave: Gulf of Mexico; Anaerobic methane oxidation; Stable isotope analysis; Sea hydrothermal vents; Food web structure; Kazan mud volcano; Florida escarpment; Trophic relationships; Benthic communauties; Lamellibrachia SP.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00016/12684/9633.pdf

Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps
Provedor de dados: 5
Autores: Portail, Marie; Olu, Karine; Dubois, Stanislas; Escobar-briones, Elva; Gelinas, Yves; Menot, Lenaick; Sarrazin, Jozee.
In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB) cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA) cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00353/46390/46018.pdf

ROV study of a giant pockmark on the Gabon continental margin
Provedor de dados: 5
Autores: Ondreas, Helene; Olu, Karine; Fouquet, Yves; Charlou, Jean-luc; Gay, Aurelien; Dennielou, Bernard; Donval, Jean-pierre; Fifis, Alexis; Nadalig, Thierry; Cochonat, Pierre; Cauquil, E; Bourillet, Jean-francois; Le Moigne, Morgan; Sibuet, Myriam.
A giant, 800-m wide pockmark, called Regab, was discovered along the Equatorial African margin at 3160-m water depth and was explored by remote operated vehicle (ROV) as part of the Zaiango (1998-2000) and Biozaire (2001-2003) projects carried out conjointly by TOTAL and a number of French research institutes. A microbathymetric map obtained using the ROV sensors shows that the pockmark actually consists of a cluster of smaller pockmarks aligned N70 along a 15-m deep depression. Methane was recorded all over the pockmark, the highest values along the axis of the depression where massive carbonate crusts and dense seep communities were also found. Several faunal species belong to the Vesicomyidae and Mytilidae bivalve families, as well as to Siboglinidae...
Tipo: Text
Palavras-chave: Gabon; Microbathymetric map; ROV; Exploration; Pockmark; Equatorial African margin.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-1239.pdf

Evidence for chemoautotrophic symbiosis in a Mediterranean cold seep clam (Bivalvia : Lucinidae): comparative sequence analysis of bacterial 16S rRNA, APS reductase and RubisCO genes
Provedor de dados: 5
Autores: Duperron, Sebastien; Fiala Medioni, Aline; Caprais, Jean-claude; Olu, Karine; Sibuet, Myriam.
Symbioses between lucinid clams (Bivalvia: Lucinidae) and autotrophic sulphide-oxidizing bacteria have mainly been studied in shallow coastal species, and information regarding deep-sea species is scarce. Here we study the symbiosis of a clam, resembling Lucinoma kazani, which was recently collected in sediment cores from new cold-seep sites in the vicinity of the Nile deep-sea fan, eastern Mediterranean, at depths ranging from 507 to 1691 m. A dominant bacterial phylotype, related to the sulphide-oxidizing symbiont of Lucinoma aequizonata, was identified in gill tissue by comparative 16S rRNA gene sequence analysis. A second phylotype, related to spirochete sequences, was identified twice in a library of 94 clones. Comparative analyses of gene sequences...
Tipo: Text
Palavras-chave: Eastern Mediterranean; Cold seeps; Lucinoma; Lucinidae; Sulphide oxidizing bacteria; Symbiosis.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2176.pdf

Globin's structure and function in vesicomyid bivalves from the Gulf of Guinea cold seeps as an adaptation to life in reduced sediments
Provedor de dados: 5
Autores: Decker, Carole; Zorn, N.; Potier, N.; Leize-wagner, E.; Lallier, F.h.; Olu, Karine; Andersen, A. C.
Vesicomyid bivalves form dense clam beds in both deep-sea cold seeps and hydrothermal vents. The species diversity within this family raises questions about niche separation and specific adaptations. To compare their abilities to withstand hypoxia, we have studied the structure and function of erythrocyte hemoglobin (Hb) and foot myoglobin (Mb) from two vesicomyid species, Christineconcha regab and Laubiericoncha chuni, collected from the Regab pockmark in the Gulf of Guinea at a depth of 3,000 m. Laubiericoncha chuni possesses three monomeric globins, G1 (15,361 Da), G2 (15,668 Da), and G3 (15,682 Da) in circulating erythrocytes (Hb), and also three globins, G1, G3, and G4 (14,786 Da) in foot muscle (Mb). Therefore, globins G2 and G4 appear to be specific...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00245/35602/34150.pdf

The distribution of scleractinian corals in the Bay of Biscay, NE Atlantic
Provedor de dados: 5
Autores: Reveillaud, J; Freiwald, A; Van Rooij, D; Le Guilloux, Erwan; Altuna, A; Foubert, A; Vanreusel, A; Olu, Karine; Henriet, J.
Studies on the distribution of scleractinian corals in the Bay of Biscay were relatively numerous during the nineteenth and the first half of the twentieth century. Yet, recent reports are scattered, sometimes unpublished, and therefore knowledge about the current coral occurrence in the area is limited. This study aims at compiling the available historical and more recently collected information on the occurrence of scleractinian corals in the Bay of Biscay. Data from two recent cruises are included and compared with previous explored coral sites from as early as 1830 up to 1995. A database of 347 records including 34 described species of scleractinians highlights that the slope of the Bay of Biscay is an important habitat for scleractinians. This could...
Tipo: Text
Palavras-chave: Biodiversity; Bay of Biscay; Slope; Scleractinia; Cold water corals.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4503.pdf

Geological and biological diversity of seeps in the Sea of Marmara
Provedor de dados: 5
Autores: Ondreas, Helene; Olu, Karine; Dupre, Stephanie; Scalabrin, Carla; Alix, Anne-sophie; Garrocq, Clément; Ruffine, Livio.
The Sea of Marmara hosts part of the North Anatolian Fault as an active submarine strike-slip fault. This area has suffered numerous earthquakes and presents a major seismic risk. Although the Sea of Marmara has been studied for many years, the link between geological morphostructures, the nature of fluids and biological communities is still rarely described. During the Marsite cruise (November 2014), dives with Remotely Operated Vehicle (ROV) VICTOR 6000 focused on detailed seafloor explorations of four different areas: the Central and Western highs and the Tekirdağ and Çinarcik basins. Based on 130 h of in situ videos, high-resolution seafloor mapping of seeps was conducted, emphasizing their significant geological and biological diversity from one...
Tipo: Text
Palavras-chave: Sea of Marmara; Cold seeps; Fluids; Seismogenic faults; Chemosynthetic fauna; Methane.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00624/73623/73040.pdf

Amphi-Atlantic cold-seep Bathymodiolus species complexes across the equatorial belt
Provedor de dados: 5
Autores: Olu, Karine; Von Cosel, R; Hourdez, S; Carney, S; Jollivet, D.
Deep-sea bivalves of the subfamily Bathymodiolinae (family Mytilidae) are very widespread and form dense beds in reduced environments such as hydrothermal vents and cold seeps. Bathymodiolus mussels recently discovered on African cold seeps strangely resemble Gulf of Mexico and Barbados seep species. This raises intriguing questions regarding their taxonomic relationships and their dispersal capabilities across the Atlantic equatorial belt. The morphological study of the shell and soft parts of mussels from either sites of the Atlantic shows that they form two distinct groups: the Bathymodiolus boomerang group (also including Bathymodiolus heckerae and a species from Africa), and the Bathymodiolus childressi group (also including Bathymodiolus mauritanicus...
Tipo: Text
Palavras-chave: RDNA ITS2; Mitochondrial cytochrome oxydase; Amphi Atlantic species; Cold seeps; Bathymodiolus.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-4064.pdf

Fauna and habitat types driven by turbidity currents in the lobe complex of the Congo deep sea fan
Provedor de dados: 5
Autores: Sen, Arunima; Dennielou, Bernard; Tourolle, Julie; Arnaubec, Aurelien; Rabouille, Christophe; Olu, Karine.
This study characterizes the habitats and megafaunal community of the Congo distal lobe complex driven by turbidity currents through the use of remotely operated vehicle (ROV) still imagery transects covering distances in the order of kilometers. In this sedimentary, abyssal area about 5000 m deep and 750 km offshore from western Africa, large quantities of deposited organic material supplied by the Congo River canyon and channel support aggregations of large sized foraminifers (Bathysiphon sp.) and vesicomyid clams (Christineconcha regab, Abyssogena southwardae) often associated with methane cold seeps, as well as opportunistic deep-sea scavengers. Additionally, bacterial mats, assumed to be formed by large sulfur-oxidizing filamentous bacteria (Beggiatoa...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00385/49614/50126.pdf

Morphology, structure, composition and build-up processes of the active channel-mouth lobe complex of the Congo deep-sea fan with inputs from remotely operated underwater vehicle (ROV) multibeam and video surveys
Provedor de dados: 5
Autores: Dennielou, Bernard; Droz, Laurence; Babonneau, Nathalie; Jacq, Celine; Bonnel, Cedric; Picot, Marie; Le Saout, Morgane; Saout, Yohan; Bez, Martine; Savoye, Bruno; Olu, Karine; Rabouille, Christophe.
The detailed structure and composition of turbiditic channel-mouth lobes is still largely unknown because they commonly lie at abyssal water depths, are very thin and are therefore beyond the resolution of hull-mound acoustic tools. The morphology, structure and composition of the Congo turbiditic channel-mouth lobe complex (90×40 km; 2525 km2) were investigated with hull-mounted swath bathymetry, air gun seismics, 3.5 kHz sub-bottom profiler, sediment piston cores and also with high-resolution multibeam bathymetry and video acquired with a Remote Operating Vehicle (ROV). The lobe complex lies 760 km off the Congo River mouth in the Angola abyssal plain between 4740 and 5030 m deep. It is active and is fed by turbidity currents that deposit several...
Tipo: Text
Palavras-chave: Congo deep-sea fan; Lobe; Lobe complex; Channel; Channel-Lobe Transition Zone; Angola basin; Slump; Slide; Debrite; Turbidite; ROV; Bathymetry; Seismic; Sediment core.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00378/48976/49383.pdf

Diversity of symbioses between chemosynthetic bacteria and metazoans at the Guiness cold seep site (Gulf of Guinea, West Africa)
Provedor de dados: 5
Autores: Duperron, Sebastien; Rodrigues, Clara F.; Leger, Nelly; Szafranski, Kamil; Decker, Carole; Olu, Karine; Gaudron, Sylvie M.
Fauna from deep-sea cold seeps worldwide is dominated by chemosymbiotic metazoans. Recently, investigation of new sites in the Gulf of Guinea yielded numerous new species for which symbiosis was strongly suspected. In this study, symbioses are characterized in five seep-specialist metazoans recently collected from the Guiness site located at ∼600 m depth. Four bivalve and one annelid species belonging to families previously documented to harbor chemosynthetic bacteria were investigated using bacterial marker gene sequencing, fluorescence in situ hybridization, and stable isotope analyses. Results support that all five species display chemosynthetic, sulfur-oxidizing γ-proteobacteria. Bacteria are abundant in the gills of bivalves, and in the trophosome of...
Tipo: Text
Palavras-chave: Acharax; Calyptogena; Chemosynthesis; Cold seeps; Elenaconcha; Gulf of Guinea; Lamellibrachia; Symbiosis; Thyasira.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00133/24418/22432.pdf

Habitat heterogeneity influences cold-seep macrofaunal communities within and among seeps along the Norwegian margin – Part 2: contribution of chemosynthesis and nutritional patterns
Provedor de dados: 5
Autores: Decker, Carole; Olu, Karine.
The relative contribution of chemosynthesis in heterotrophic fauna at seeps is known to be influenced by depth and by habitat. Using stable isotopes of carbon and nitrogen, we investigated macro- and megafaunal nutritional patterns in Norwegian margin cold seeps by comparing food webs both among habitats within a seep site and between different sites. The very active Håkon Mosby mud volcano (HMMV) is characterized by geochemical gradients, microbial activity and faunal zonation from the centre to the periphery. The Storegga Slide (600–900 m depth) has pockmarks with patchy less active seeps, and also shows concentric zonation of habitats but at much smaller spatial scale. The dominant carbon source for macrofaunal nutrition in both areas was...
Tipo: Text
Palavras-chave: Cold-seep; Macrofaunal nutrition; Methane-derived carbon; Norwegian margin; Stable isotope analysis.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00074/18518/16164.pdf

Fluid flow regimes and growth of a giant pockmark
Provedor de dados: 5
Autores: Marcon, Yann; Ondreas, Helene; Sahling, Heiko; Bohrmann, Gerhard; Olu, Karine.
Pockmarks are seafloor depressions commonly associated with fluid escape from the seabed and are believed to contribute noticeably to the transfer of methane into the ocean and ultimately into the atmosphere. They occur in many different areas and geological contexts, and vary greatly in size and shape. Nevertheless, the mechanisms of pockmark growth are still largely unclear. Still, seabed methane emissions contribute to the global carbon budget, and understanding such processes is critical to constrain future quantifications of seabed methane release at local and global scales. The giant Regab pockmark (9 degrees 42.6' E, 5 degrees 47.8' S), located at 3160 m water depth near the Congo deep-sea channel (offshore southwestern Africa), was investigated...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00186/29731/28293.pdf

The Moira Mounds, small cold-water coral banks in the Porcupine Seabight, NE Atlantic: Part A an early stage growth phase for future coral carbonate mounds?
Provedor de dados: 5
Autores: Wheeler, A. J.; Kozachenko, M.; Henry, L. -a.; Foubert, A.; De Haas, H.; Huvenne, V. A. I.; Masson, D.c.; Olu, Karine.
This paper presents a comprehensive overview of the Moira Mounds in the Porcupine Seabight, combining a review of currently published material with new data and interpretations. The Moira Mounds are circular to ovoid-shaped individual or clustered coral banks (referred to as "scleractinian spaced cluster macroreefs") located in the Belgica (carbonate) mound province, Porcupine Seabight, west of Ireland. They are up to 10 m high and 20 to 35 m in diameter. For the first time, a map showing the complete extent and location of the Moira Mounds is published, revealing 256 examples grouped into four areas mainly between 800 and 1100 m water depth. ROV groundtruthing revealed the importance of bedload sand transport in Moira Mound formation and development...
Tipo: Text
Palavras-chave: Cold-water coral; Coral carbonate mound; Benthic processes; Biogeological processes; Marine geology; NE Atlantic.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00035/14633/12050.pdf

Cold-seep assemblages on a giant pockmark off West Africa: spatial patterns and environmental control
Provedor de dados: 5
Autores: Olu, Karine; Caprais, Jean-claude; Fifis, Alexis; Fabri, Marie-claire; Galeron, Joelle; Budzinsky, H; Le Menach, K; Khripounoff, Alexis; Ondreas, Helene; Sibuet, Myriam.
A giant pockmark colonised by dense cold-seep assemblages near 3160 m depth along the Congo-Angola margin has been surveyed by the ROV Victor 6000. The quantitative distribution of chemosynthetic communities was mapped along the dive tracks from a video study using GIS and image mosaicking. Several types of faunal assemblages, either dominated by bivalves of the families Mytilidae (Bathmodiolus sp.) Vesicom idae (Calyptogena sp., 'Vesicomya' aff. chuni), or by Siboglinidae polychaetes (Escarpia southwardae) were mapped over the 800-m diameter pockmark area and sampled for fauna, water and sediment. The isotopic analyses (delta C-13) of tissues from symbiont-bearing species were within the range typical of nutrition via symbiosis using methane for mussels...
Tipo: Text
Palavras-chave: Symbiont bearing species; Spatial distribution; Methane; Megafauna; Cold seeps.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2681.pdf

Variability in gas and solute fluxes through deep-sea chemosynthetic ecosystems inhabited by vesicomyid bivalves in the gulf of Guinea
Provedor de dados: 5
Autores: Khripounoff, Alexis; Caprais, Jean-claude; Decker, Carole; Essirard, Mikael; Le Bruchec, Julie; Noel, Philippe; Olu, Karine.
We have studied two species of vesicomyid bivalves inhabiting different areas of sulfide-rich sediments in association with methane seepage at two pockmarks located at about 650 m and 3150 m depth, respectively, along the Gabon-Congo margin, and organic-rich sediments in the deepest zone (4950 m depth) of the Congo deep-sea fan. Benthic chambers Calmar were deployed on three study sites to assess gas and solute exchanges at the water-sediment interface. We recorded in situ measurements of oxygen, total carbon dioxide, ammonium, methane, and sulfide in two clam beds at each site. At all sites, irrespective of which the vesicomyid species are present, oxygen consumption was high and variable (28–433 mmol m−2 d−1) as was total carbon dioxide emission (36–1857...
Tipo: Text
Palavras-chave: Benthic chamber; Cold-seep ecosystem; Reduced sediment; Gas fluxes; Vesicomyid bivalves; Gulf of Guinea.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00226/33746/32160.pdf

Physical Proximity May Promote Lateral Acquisition of Bacterial Symbionts in Vesicomyid Clams
Provedor de dados: 5
Autores: Decker, Carole; Olu, Karine; Arnaud-haond, Sophie; Duperron, Sebastien.
Vesicomyid clams harbor intracellular sulfur-oxidizing bacteria that are predominantly maternally inherited and co-speciate with their hosts. Genome recombination and the occurrence of non-parental strains were recently demonstrated in symbionts. However, mechanisms favoring such events remain to be identified. In this study, we investigated symbionts in two phylogenetically distant vesicomyid species, Christineconcha regab and Laubiericoncha chuni, which sometimes co-occur at a cold-seep site in the Gulf of Guinea. We showed that each of the two species harbored a single dominant bacterial symbiont strain. However, for both vesicomyid species, the symbiont from the other species was occasionally detected in the gills using fluorescence in situ...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00153/26427/24527.pdf

Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
Provedor de dados: 5
Autores: Rabouille, C.; Dennielou, Bernard; Baudin, F.; Raimonet, M.; Droz, Laurence; Khripounoff, Alexis; Martinez, P.; Mejanelle, L.; Michalopoulos, P.; Pastor, Lucie; Pruski, A.; Ragueneau, Olivier; Reyss, J.-l.; Ruffine, Livio; Schnyder, J.; Stetten, E.; Taillefert, M.; Tourolle, Julie; Olu, Karine.
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...
Tipo: Text
Palavras-chave: Present; Paleoceanography; South Atlantic; Inorganic geochemistry; Organic geochemistry; Sedimentology-marine cores.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00511/62289/66720.pdf

Comparative study of vent and seep macrofaunal communities in the Guaymas Basin
Provedor de dados: 5
Autores: Portail, Marie; Olu, Karine; Escobar-briones, E.; Caprais, Jean-claude; Menot, Lenaick; Waeles, Mathieu; Cruaud, Perrine; Sarradin, Pierre-marie; Godfroy, Anne; Sarrazin, Jozee.
Understanding the ecological processes and connectivity of chemosynthetic deep-sea ecosystems requires comparative studies. In the Guaymas Basin (Gulf of California, Mexico), the presence of seeps and vents in the absence of a biogeographic barrier, and comparable sedimentary settings and depths offers a unique opportunity to assess the role of ecosystem-specific environmental conditions on macrofaunal communities. Six seep and four vent assemblages were studied, three of which were characterised by common major foundation taxa: vesicomyid bivalves, siboglinid tubeworms and microbial mats. Macrofaunal community structure at the family level showed that density, diversity and composition patterns were primarily shaped by seep- and vent-common abiotic...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00280/39076/37642.pdf

Distribution and temporal variation of mega-fauna at the Regab pockmark (Northern Congo Fan), based on a comparison of videomosaics and geographic information systems analyses
Provedor de dados: 5
Autores: Marcon, Yann; Sahling, Heiko; Allais, Anne-gaelle; Bohrmann, Gerhard; Olu, Karine.
The Regab pockmark is a large cold seep area located 10 km north of the Congo deep sea channel at about 3160 m water depth. The associated ecosystem hosts abundant fauna, dominated by chemosynthetic species such as the mussel Bathymodiolus aff. boomerang, vestimentiferan tubeworm Escarpia southwardae, and vesicomyid clams Laubiericoncha chuni and Christineconcha regab. The pockmark was visited during the West African Cold Seeps (WACS) cruise with RV Pourquoi Pas? in February 2011, and a 14,000-m2 high-resolution videomosaic was constructed to map the most populated area and to describe the distribution of the dominant megafauna (mussels, tubeworms and clams). The results are compared with previous published works, which also included a videomosaic in the...
Tipo: Text
Palavras-chave: Cold seep; Fauna; Mosaic; Pockmark; Regab; Temporal variation.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00144/25528/23765.pdf

Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan
Provedor de dados: 5
Autores: Olu, Karine; Decker, Carole; Pastor, Lucie; Caprais, Jean-claude; Khripounoff, Alexis; Morineaux, Marie; Ain Baziz, M.; Menot, Lenaick; Rabouille, C.
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...
Tipo: Text
Palavras-chave: Chemosynthesis-based ecosystems; Cold seeps; Organic rich sediments; Macrofaunal communities.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00384/49561/50053.pdf

The Ecological Role of Patchy Cold-Water Coral Habitats: Does Coral Density Influence Local Biodiversity in Submarine Canyons of the Bay of Biscay?
Provedor de dados: 5
Autores: Menot, Lenaick; Van Den Beld, Inge; Arnaud-haond, Sophie; Bourillet, Jean-francois; Davies, J.s.; Guillaumont, Brigitte; Olu, Karine.
In the Bay of Biscay, Cold Water Coral (CWC) habitats have been mapped in 24 out of a hundred known submarine canyons. The footprint of ROV or towed-camera transects is small compared to the size of these canyons but still, known CWC habitats totalize a linear of 46 km. The distribution of these habitats, dominated by reef-building scleractinians, antipatharians, alcyonaceans and pennatulids, is however patchy and their median size is small, ranging from 6 to 65 m. While the preservation of these Vulnerable Marine Ecosystems has become essential, all CWC habitats will not be benefit from conservation strategies due to their widespread and patchy distribution. Priorities must thus be defined. Among the criteria for such prioritization, we explore here the...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00469/58077/60484.pdf

An overview of chemosynthetic symbioses in bivalves from the North Atlantic and Mediterranean Sea
Provedor de dados: 5
Autores: Duperron, Sebastien; Gaudron, Sylvie M.; Rodrigues, Clara; Cunha, Marina R.; Decker, Carole; Olu, Karine.
Deep-sea bivalves found at hydrothermal vents, cold seeps and organic falls are sustained by chemosynthetic bacteria which ensure part or all of their carbon nutrition. These symbioses are of prime importance for the functioning of the ecosystems. Similar symbioses occur in other bivalve species living in shallow and coastal reduced habitats worldwide. In recent years, several deep-sea species have been investigated from continental margins around Europe, West Africa, East America, the Gulf of Mexico, and from hydrothermal vents on the Mid-Atlantic Ridge. In parallel, numerous more easily accessible shallow marine species were studied. We here provide a summary of the current knowledge available on chemosymbiotic bivalves in the area ranging west-to-east...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00133/24417/22431.pdf

First record of the coloured righteye flounder, Poecilopsetta colorata (Teleostei: Poecilopsettidae) from the Sakalaves seamounts in the Mozambique Channel
Provedor de dados: 5
Autores: Chen, Wei-jen; Chen, Jhen-nien; Pernet, Marie Eve Julie; Olu, Karine.
Background: The coloured righteye flounder, Poecilopsetta colorata Günther, 1880 was previously known from the eastern Indian Ocean to the South China Sea and Indonesia. Here, a new record from the western Indian Ocean is reported. Results: The new record is based on a specimen collected on the Sakalaves seamounts at 375 m in depth in the Mozambique Channel during a recent oceanographic survey. Four other teleost fish species including an uncommon ophidiid species, Neobythites somaliaensis Nielsen, 1995 were also collected on the same seamounts.  Conclusions: The presence of P. colorata in the Mozambique Channel suggests a broad and Indo-West Pacific wide distribution for this relatively rare deep-sea species. The sequence of the cytochrome oxidase...
Tipo: Text
Palavras-chave: Fishes; New record; Distribution; Western Indian Ocean; Mozambique Channel; Sakalaves seamounts; COI; PAMELA-MOZ01 cruise.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00353/46385/46009.pdf

Phylogeny and Diversification Patterns among Vesicomyid Bivalves
Provedor de dados: 5
Autores: Decker, Carole; Olu, Karine; Cunha, Regina L.; Arnaud, Sophie.
Vesicomyid bivalves are among the most abundant and diverse symbiotic taxa in chemosynthetic-based ecosystems: more than 100 different vesicomyid species have been described so far. In the present study, we investigated the phylogenetic positioning of recently described vesicomyid species from the Gulf of Guinea and their western Atlantic and Pacific counterparts using mitochondrial DNA sequence data. The maximum-likelihood (ML) tree provided limited support for the recent taxonomic revision of vesicomyids based on morphological criteria; nevertheless, most of the newly sequenced specimens did not cluster with their morphological conspecifics. Moreover, the observed lack of geographic clustering suggests the occurrence of independent radiations followed by...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00076/18729/16301.pdf

Seafloor geological studies above active gas chimneys off Egypt (Central nile deep sea fan)
Provedor de dados: 5
Autores: Dupre, Stephanie; Woodside, J; Foucher, Jean-paul; De Lange, G; Mascle, J; Boetius, A; Mastalerz, V; Stadnitskaia, A; Ondreas, Helene; Huguen, C; Harmegnies, Francois; Gontharet, Swanne; Loncke, L; Deville, E; Niemann, H; Omoregie, E; Olu, Karine; Fiala Medioni, A; Dahlmann, A; Caprais, Jean-claude; Prinzhofer, A; Sibuet, Myriam; Pierre, C; Damste, J.
Four mud volcanoes of several kilometres diameter named Amon, Osiris, Isis, and North Alex and located above gas chimneys on the Central Nile Deep Sea Fan, were investigated for the first time with the submersible Nautile. One of the objectives was to characterize the seafloor morphology and the seepage activity across the mud volcanoes. The seepage activity was dominated by emissions of methane and heavier hydrocarbons associated with a major thermal contribution. The most active parts of the mud volcanoes were highly gas-saturated (methane concentrations in the water and in the sediments, respectively, of several hundreds of nmol/L and several mmol/L of wet sediment) and associated with significantly high thermal gradients (at 10 m below the seafloor,...
Tipo: Text
Palavras-chave: Seafloor morphology; Methane; Authigenic carbonate precipitation; Gas chimneys; Mud breccia; Mud volcanoes; Fluid seepage; Nile fan.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-4455.pdf

Large Vesicomyidae (Mollusca: Bivalvia) from cold seeps in the Gulf of Guinea off the coasts of Gabon, Congo and northern Angola
Provedor de dados: 5
Autores: Von Cosel, Rudo; Olu, Karine.
Two new genera and three new species of large Vesicomyidae are described from cold-seep sites on pockmarks and other sulfide-rich environments in the Gulf of Guinea (tropical east Atlantic) off Gabon, Congo (Brazzaville) and northern Angola, from 500 to 4000 m depth: "Catyptogena" (s.l.) regab n. sp., Wareniconcha (n.g.) guineensis (Thiele and Jaeckel 1931), Elenaconcha guiness n.g. n. sp., and Isorropodon atalantae n. sp. For two other species already taken by the R/V Valdivia in 1898, Calyptogena valdiviae (Thiele and Jaeckel 1931) and Isorropodon striatum (Thiele and Jaeckel 1931) new localities were discovered, and the species are rediscussed. E. guiness n.g. n.sp. is also recorded from off Banc d'Arguin, Mauritania, collected by commercial fishing...
Tipo: Text
Palavras-chave: New Taxa; Systematics; Eastern Atlantic; Gulf of Guinea; Cold seeps; Vesicomyidae.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7443.pdf

Comments on the paper of Gay et al. (2006) Seafloor facies related to upward methane flux within a Giant Pockmark of the Lower Congo Basin. Marine Geology 226 : 81-95
Provedor de dados: 5
Autores: Olu, Karine.
The paper by Gay et al. describes a giant pockmark on the basis of geological and biological data collected during ROV dives. The description of seep communities based on a transect across the pockmark includes some mistakes. Part of the description of the fauna is attributed to Olu-Le Roy et al. (2003) and includes data that have not been presented in this oral communication. An "evolutive model" is proposed, based on these data and on an incorrect interpretation of symbiotic species requirements (classification of methane vs sulfide dependent species). In this note, I would like to point out the mistakes of this paper and express why their model cannot be used to describe the reality of the seabed.
Tipo: Text
Palavras-chave: BIOZAIRE; ZAIANGO; Palaeochannel; Hydrates; Chemosynthesis; Seafloor facies; Fluid migration; Pockmark.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2276.pdf

The Magellan mound province in the Porcupine Basin
Provedor de dados: 5
Autores: Huvenne, Veerle A. I.; Bailey, W. R.; Shannon, P. M.; Naeth, J; Di Primio, R.; Henriet, J. P.; Horsfield, B.; De Haas, H.; Wheeler, A; Olu, Karine.
The Magellan mound province is one of the three known provinces of carbonate mounds or cold-water coral banks in the Porcupine Seabight, west of Ireland. It has been studied in detail using a large and varied data set: 2D and 3D seismic data, sidescan sonar imagery and video data collected during ROV deployment have been used to describe the mounds in terms of origin, growth processes and burial. The aim of this paper is to present the Magellan mounds and their setting in an integrated, holistic way. More than 1,000 densely spaced and mainly buried mounds have been identified in the area. They all seem to be rooted on one seismic reflection, suggesting a sudden mound start-up. Their size and spatial distribution characteristics are presented, together with...
Tipo: Text
Palavras-chave: Numerical basin modelling; Fault analysis; Mound morphology; Spatial distribution; Porcupine Basin; Cold water corals; Carbonate mounds.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2312.pdf

Can the hemoglobin characteristics of vesicomyid clam species influence their distribution in deep-sea sulfide-rich sediments? A case study in the Angola Basin
Provedor de dados: 5
Autores: Decker, Carole; Zorn, N.; Le Bruchec, J.; Caprais, Jean-claude; Potier, N.; Leize-wagner, E.; Lallier, F. H.; Olu, Karine; Andersen, A. C.
Vesicomyids live in endosymbiosis with sulfur-oxidizing bacteria and therefore need hydrogen sulfide to survive. They can nevertheless live in a wide range of sulfide and oxygen levels and depths, which may explain the exceptional diversity of this clam family in deep-sea habitats. In the Gulf of Guinea, nine species of vesicomyid clams are known to live in cold-seep areas with pockmarks from 600 to 3200 m deep, as well as in the organic-rich sediments of the Congo deep-sea fan at 5000 m deep. Our previous study showed that two species living in a giant pockmark have different oxygen carriers, suggesting different adaptations to hypoxia. Here, we studied the hemoglobin structure and oxygen affinity in three other species, Calyptogena valdiviae, Elenaconcha...
Tipo: Text
Palavras-chave: Hemoglobin; Mass spectrometry; Oxygen affinity; Symbiont-bearing bivalve; Blood-clams; Cold seeps; Sulfide-rich sediments.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00358/46961/46875.pdf

Does macrofaunal nutrition vary among habitats at the Hakon Mosby mud volcano?
Provedor de dados: 5
Autores: Decker, Carole; Olu, Karine.
The Hakon Mosby mud volcano (HMMV) is one of the most studied cold-seep sites in Europe. Its exceptional fluid expulsion activity and large geochemical gradients from the centre to the periphery support dense biological communities and induce spatial heterogeneity in microbial activity and faunal zonation. At this site, the macrofauna has been little studied and the variability in its macrobenthic nutrition has not yet been investigated. In this study, based on the analysis of the stable isotopes of carbon and nitrogen, we determined nutritional patterns for macrofauna communities in three different habitats (microbial mats, sediment adjacent to the mat and Siboglinidae polychaete fields). delta C-13 values of macrofaunal tissues varied among two habitats...
Tipo: Text
Palavras-chave: Cold seep; Hakon Mosby; Macrofaunal nutrition; Stable isotope analysis.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00019/13043/10161.pdf

Impacts of an Eruption on Cold-Seep Microbial and Faunal Dynamics at a Mud Volcano
Provedor de dados: 5
Autores: Girard, Fanny; Sarrazin, Jozee; Olu, Karine.
Cold seeps are widespread in the deep sea and, like other chemosynthesis-based ecosystems, often host high faunal biomass. Temporal changes at seeps have been inferred by comparing communities at different successional stages; nonetheless, temporal studies in seep ecosystems are rare. Using data collected as part of a benthic observatory, we characterized intra-annual microbial and faunal dynamics in a microbial mat habitat on the Håkon Mosby mud volcano (1256 m depth; Barents Sea), and evaluated the effects of a mud eruption on the biota. Video sequences recorded twice daily for 4.5 months with an autonomous imaging module were analyzed to quantify changes in microbial mat cover and megafaunal density and behavior. In addition, time series data for...
Tipo: Text
Palavras-chave: Håkon Mosby Mud Volcano; LOOME; Arctic; Beggiatoa; Deep-sea observatories; Time series; Megafauna.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00624/73631/73069.pdf

Influence of seep emission on the non-symbiont-bearing fauna and vagrant species at an active giant pockmark in the Gulf of Guinea (Congo-Angola margin)
Provedor de dados: 5
Autores: Olu, Karine; Caprais, Jean-claude; Galeron, Joelle; Causse, R.; Von Cosel, R.; Budzinski, H.; Le Menach, K.; Le Roux, C.; Levache, D.; Khripounoff, Alexis; Sibuet, Myriam.
Detailed surveying with an ROV found that a dense and diverse cold-seep community colonises a giant pockmark located at 3200 m depth, 8 km north from the deep Congo channel. Several types of assemblages, either dominated by Mytilidae and Vesicomyidae bivalves or Siboglinidae polychaetes, are distributed on the 800-m diameter active area. The site is characterised by a most active central zone in a depression with abundant carbonate concretions and high methane fluxes where high-density clusters of mussels and siboglinids dominate. In contrast, the peripheral zones display large fields of dead and live vesicomyids on soft sediment, with a lower mean density and lower methane concentration in seawater. The associated megafauna includes Alvinocarididae...
Tipo: Text
Palavras-chave: Congo Angola margin; Atlantic Equatorial African margin; Vagrant species; Isotopic signature; Megafauna; Cold seep.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7478.pdf

Cold-water coral habitats in submarine canyons of the Bay of Biscay
Provedor de dados: 5
Autores: Van Den Beld, Inge; Bourillet, Jean-francois; Arnaud-haond, Sophie; De Chambure, Laurent; Davies, Jaime S; Guillaumont, Brigitte; Olu, Karine; Menot, Lenaick.
The topographical and hydrological complexity of submarine canyons, coupled with high substratum heterogeneity, make them ideal environments for cold-water coral (CWC) habitats. These habitats, including reefs, are thought to provide important functions for many organisms. The canyons incising the continental slope of the Bay of Biscay have distinct morphological differences from the north to the south. CWCs have been reported from this basin in the late 19th century; however, little is known about their present-day distribution, diversity and environmental drivers in the canyons. In this study, the characteristics and distribution of CWC habitats in the submarine canyons of the Bay of Biscay are investigated. Twenty-four canyons and three locations...
Tipo: Text
Palavras-chave: Cold-water corals; Habitats; Submarine canyons; Bay of Biscay; NE Atlantic; ROV; Towed camera; Distribution.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00382/49343/49733.pdf

Deep-Sea Biodiversity in the Mediterranean Sea: The Known, the Unknown, and the Unknowable
Provedor de dados: 5
Autores: Danovaro, Roberto; Batista Company, Joan; Corinaldesi, Cinzia; D'Onghia, Gianfranco; Galil, Bella; Gambi, Cristina; Gooday, Andrew J.; Lampadariou, Nikolaos; Luna, Gian Marco; Morigi, Caterina; Olu, Karine; Polymenakou, Paraskevi; Ramirez-llodra, Eva; Sabbatini, Anna; Sarda, Francesc; Sibuet, Myriam; Tselepides, Anastasios.
Deep-sea ecosystems represent the largest biome of the global biosphere, but knowledge of their biodiversity is still scant. The Mediterranean basin has been proposed as a hot spot of terrestrial and coastal marine biodiversity but has been supposed to be impoverished of deep-sea species richness. We summarized all available information on benthic biodiversity (Prokaryotes, Foraminifera, Meiofauna, Macrofauna, and Megafauna) in different deep-sea ecosystems of the Mediterranean Sea (200 to more than 4,000 m depth), including open slopes, deep basins, canyons, cold seeps, seamounts, deep-water corals and deep-hypersaline anoxic basins and analyzed overall longitudinal and bathymetric patterns. We show that in contrast to what was expected from the sharp...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00011/12206/8974.pdf

Biodiversity of Cold Seep Ecosystems Along the European Margins
Provedor de dados: 5
Autores: Vanreusel, Ann; Andersen, Ann C.; Boetius, Antje; Connelly, Douglas; Cunha, Marina R.; Decker, Carole; Hilario, Ana; Kormas, Konstantinos Ar.; Maignien, Lois; Olu, Karine; Pachiadaki, Maria; Ritt, Benedicte; Rodrigues, Clara; Sarrazin, Jozee; Tyler, Paul; Van Gaever, Saskia; Vanneste, Heleen.
During the European Commission's Framework Six Programme, HERMES, we investigated three main areas along the European margin, each characterized by the presence of seep-related structures exhibiting different intensity of activity and biological diversity. These areas are: (1) the Nordic margin with the Hakon Mosby mud volcano and many pockmarks, (2) the Gulf of Cadiz, and (3) the eastern Mediterranean with its hundreds of mud volcanoes and brine pool structures. One of the main goals of the HERMES project was to unravel the biodiversity associated with these seep-associated ecosystems, and to understand their driving forces and functions, using an integrated approach. Several multidisciplinary research cruises to these three areas provided evidence of...
Tipo: Text
Palavras-chave: Mosby mud volcano; Gulf of mexico; Cadiz ne atlantic; Deep sea fan; Community structure; Microbial communities; Fluid flow; Mediterranean sea; Carbonate crusts; Norwegian sea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6375.pdf

Seamounts, plateaus and governance issues in the southwest Indian Ocean, with emphasis on fisheries management and marine conservation, using the Walters Shoal as a case study for implementing a protection framework
Provedor de dados: 5
Autores: Marsac, Francis; Galletti, Florence; Ternon, Jean-francois; Romanov, Evgeny V.; Demarcq, Herve; Corbari, Laure; Bouchet, Philippe; Roest, Walter; Jorry, Stephan; Olu, Karine; Loncke, Lies; Roberts, Michael J.; Ménard, Frédéric.
There is a growing interest in the management of seamounts of the South Western Indian Ocean (SWIO) both in waters under national jurisdictions and in the Areas Beyond National Jurisdiction (ABNJ). On the one hand, new scientific knowledge has been gathered through various oceanographic cruises during the past decade and, on the other hand, new agreements are under consideration globally to promote conservation and sustainable use of the biodiversity in the ABNJ, where the deep sea ecosystems associated to seamounts are a growing matter of concern. SWIO seamounts have attracted interests from fishing operators since the 1960s, while mining exploration contracts have been recently granted. Seamounts are known to shelter rich, fragile and poorly resilient...
Tipo: Text
Palavras-chave: International Law of the Sea; Vulnerable Marine Ecosystems; Deep-sea fisheries; Deep-sea mining; Benthic biodiversity; Saya de Malha Bank; South Indian Ocean Fisheries Agreement; Areas Beyond National Jurisdiction; Amended Nairobi Convention; Marine protected areas.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00598/71049/69362.pdf

Morphology and environment of cold-water coral carbonate mounds on the NW European margin
Provedor de dados: 5
Autores: Wheeler, Andrew J.; Beyer, A; Freiwald, A; De Haas, H; Huvenne, V. A. I.; Kozachenko, M; Olu, Karine; Opderbecke, Jan.
Cold-water coral carbonate mounds, owing their presence mainly to the framework building coral Lophelia pertusa and the activity of associated organisms, are common along the European margin with their spatial distribution allowing them to be divided into a number of mound provinces. Variation in mound attributes are explored via a series of case studies on mound provinces that have been the most intensely investigated: Belgica, Hovland, Pelagia, Logachev and Norwegian Mounds. Morphological variation between mound provinces is discussed under the premise that mound morphology is an expression of the environmental conditions under which mounds are initiated and grow. Cold-water coral carbonate mounds can be divided into those exhibiting "inherited"...
Tipo: Text
Palavras-chave: Seabed mapping; Environmental setting; Morphology; Cold water coral; Carbonate mound.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2411.pdf

The use of multibeam backscatter and bathymetry as a means of identifying faunal assemblages in a deep-sea cold seep
Provedor de dados: 5
Autores: Sen, Arunima; Ondreas, Helene; Gaillot, Arnaud; Marcon, Yann; Augustin, Jean-marie; Olu, Karine.
Deep-sea ecosystems have attracted considerable commercial interest in recent years because of their potential to sustain a diverse range of mankind's industrial needs. If these systems are to be preserved or exploited in a sustainable manner, mapping habitats and species distributions is critical. As biodiversity at cold-seeps or other deep-sea ecosystems is driven by habitat heterogeneity, imagery is the obvious choice for characterizing these systems and has indeed proven extremely valuable towards mapping biogenic habitats formed by dense aggregations of large sized species, such as coral reefs, tubeworm bushes or bivalve beds. However, the acquisition of detailed images with resolution sufficient for reliable identification is extremely time...
Tipo: Text
Palavras-chave: Mapping; Cold seeps; Multibeam; Bathymetry; Backscatter; Biogenic habitats.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00312/42286/41612.pdf

High connectivity across the fragmented chemosynthetic ecosystems of the deep Atlantic Equatorial Belt: efficient dispersal mechanisms or questionable endemism?
Provedor de dados: 5
Autores: Teixeira, Sara; Olu, Karine; Decker, Carole; Cunha, Regina L.; Fuchs, Sandra; Hourdez, Stephane; Serrao, Ester A.; Arnaud-haond, Sophie.
Chemosynthetic ecosystems are distributed worldwide in fragmented habitats harbouring seemingly highly specialized communities. Yet, shared taxa have been reported from highly distant chemosynthetic communities. These habitats are distributed in distinct biogeographical regions, one of these being the so-called Atlantic Equatorial Belt (AEB). Here, we combined genetic data (COI) from several taxa to assess the possible existence of cryptic or synonymous species and to detect the possible occurrence of contemporary gene flow among populations of chemosynthetic species located on both sides of the Atlantic. Several Evolutionary Significant Units (ESUs) of Alvinocarididae shrimp and Vesicomyidae bivalves were found to be shared across seeps of the AEB. Some...
Tipo: Text
Palavras-chave: Atlantic equatorial belt; Chemosynthetic habitats; Deep-sea connectivity; Endemic bivalves; Endemic shrimp; Genetic diversity; Microsatellite markers; Mitochondrial COI gene.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00157/26789/24950.pdf

Chiridota heheva—the cosmopolitan holothurian
Provedor de dados: 5
Autores: Thomas, Elin A.; Liu, Ruoyu; Amon, Diva; Copley, Jon T.; Glover, Adrian G.; Helyar, Sarah J.; Olu, Karine; Wiklund, Helena; Zhang, Haibin; Sigwart, Julia D.
Chemosynthetic ecosystems have long been acknowledged as key areas of enrichment for deep-sea life, supporting hundreds of endemic species. Echinoderms are among the most common taxa inhabiting the periphery of chemosynthetic environments, and of these, chiridotid holothurians are often the most frequently observed. Yet, published records of chiridotids in these habitats are often noted only as supplemental information to larger ecological studies and several remain taxonomically unverified. This study therefore aimed to collate and review all known records attributed to Chiridota Eschscholtz, 1829, and to conduct the first phylogenetic analysis into the relationship of these chiridotid holothurians across global chemosynthetic habitats. We show that...
Tipo: Text
Palavras-chave: Deep sea; Chemosynthetic environments; Opportunism; Widespread; Echinoderms.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00660/77183/78609.pdf

Apports de l’imagerie pour la cartographie et le suivi des habitats profonds
Provedor de dados: 5
Autores: Tourolle, Julie; Borremans, Catherine; Olu, Karine; Menot, Lenaick; Matabos, Marjolaine.
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00472/58324/60875.pdf

Therese Mound: a case study of coral bank development in the Belgica Mound Province, Porcupine Seabight
Provedor de dados: 5
Autores: De Mol, Ben; Kozachenko, M; Wheeler, Andy; Alvares, Hugo; Henriet, Jean-pierre; Olu, Karine.
High-resolution seismic profiles, swath bathymetry, side-scan sonar data and video imageries are analysed in this detailed study of five carbonate mounds from the Belgica mound province with special emphasis on the well-surveyed Therese Mound. The selected mounds are located in the deepest part of the Belgica mound province at water depths of 950 m. Seismic data illustrate that the underlying geology is characterised by drift sedimentation in a general northerly flowing current regime. Sigmoidal sediment bodies create local slope breaks on the most recent local erosional surface, which act as the mound base. No preferential mound substratum is observed, neither is there any indication for deep geological controls on coral bank development. Seismic evidence...
Tipo: Text
Palavras-chave: Carbonate mounds; Cold water corals; Lophelia pertusa; Porcupine Seabight; Coral banks; Belgica mound province; Therese Mound.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2307.pdf

Metazoan meiofaunal communities at cold seeps along the Norwegian margin: Influence of habitat heterogeneity and evidence for connection with shallow-water habitats
Provedor de dados: 5
Autores: Van Gaever, Saskia; Olu, Karine; Derycke, Sofie; Vanreusel, Ann.
Cold-seep environments and their associated symbiont-bearing megafaunal communities create islands of primary production for macro- and meiofauna in the otherwise monotonous and nutrient-poor deep-sea environment. To examine the spatial variation and distribution patterns of metazoan meiobenthos in different seepage-related habitats, samples were collected in two regions off Norway: several pockmarks associated with the Storegga Slide including the Nyegga pockmark area (730 m: 64 degrees N), and the active, methane-venting Hakon Mosby Mud Volcano (HMMV) west of the Barents Sea (1280 m: 72 degrees N). Based on sediment geochemistry and associated epifauna, three different habitat types were distinguished across the two regions: (1) reduced sediment with...
Tipo: Text
Palavras-chave: Terschellingia longicaudata; Halomonhystera disjuncta; Cryptic species; Nematodes; Meiobenthos; Cold seeps.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7484.pdf