Consulta: creatorFacets:"Cathalot, Cecile"
Registros recuperados: 23
Data/hora: 09/06/2024 10:49:57

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: Institutional Archive of Ifreme (ArchiMer)
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

Ecophysiological differences between vesicomyid species and metabolic capabilities of their symbionts influence distribution patterns of the deep‐sea clams
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Aquatic Eddy Correlation: Quantifying the Artificial Flux Caused by Stirring-Sensitive O2 Sensors.
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Holtappels, Moritz; Noss, Christian; Hancke, Kasper; Cathalot, Cecile; Mcginnis, Daniel F.; Lorke, Andreas; Glud, Ronnie N.
In the last decade, the aquatic eddy correlation (EC) technique has proven to be a powerful approach for non-invasive measurements of oxygen fluxes across the sediment water interface. Fundamental to the EC approach is the correlation of turbulent velocity and oxygen concentration fluctuations measured with high frequencies in the same sampling volume. Oxygen concentrations are commonly measured with fast responding electrochemical microsensors. However, due to their own oxygen consumption, electrochemical microsensors are sensitive to changes of the diffusive boundary layer surrounding the probe and thus to changes in the ambient flow velocity. The so-called stirring sensitivity of microsensors constitutes an inherent correlation of flow velocity and...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38575/37100.pdf

The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
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

Food-web complexity across hydrothermal vents on the Azores triple junction
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Portail, Marie; Brandily, Christophe; Cathalot, Cecile; Colaco, Ana; Gelinas, Yves; Husson, Berengere; Sarradin, Pierre-marie; Sarrazin, Jozee.
The assessment and comparison of food webs across various hydrothermal vent sites can enhance our understanding of ecological processes involved in the structure and function of biodiversity. The Menez Gwen, Lucky Strike and Rainbow vent fields are located on the Azores triple junction of the Mid-Atlantic Ridge. These fields have distinct depths (from 850 to 2320 m) and geological contexts (basaltic and ultramafic), but share similar faunal assemblages defined by the presence of foundation species that include Bathymodiolus azoricus, alvinocarid shrimp and gastropods. We compared the food webs of 13 faunal assemblages at these three sites using carbon and nitrogen stable isotope analyses (SIA). Results showed that photosynthesis-derived organic matter is a...
Tipo: Text
Palavras-chave: Mid-Atlantic Ridge; Hydrothermal vents; Food webs; Stable isotopes; Functional traits.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00414/52551/53732.pdf

Early diagenesis in the sediments of the Congo deep-sea fan dominated by massive terrigenous deposits: Part II – Iron–sulfur coupling
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Taillefert, Martial; Beckler, Jordon S.; Cathalot, Cecile; Michalopoulos, Panagiotis; Corvaisier, Rudolph; Kiriazis, Nicole; Caprais, Jean-claude; Pastor, Lucie; Rabouille, Christophe.
Deep-sea fans are well known depot centers for organic carbon that should promote sulfate reduction. At the same time, the high rates of deposition of unconsolidated metal oxides from terrigenous origin may also promote metal-reducing microbial activity. To investigate the eventual coupling between the iron and sulfur cycles in these environments, shallow sediment cores (&lt; 50 cm) across various channels and levees in the Congo River deep-sea fan (~5000 m) were profiled using a combination of geochemical methods. Interestingly, metal reduction dominated suboxic carbon remineralization processes in most of these sediments, while dissolved sulfide was absent. In some ‘hotspot’ patches, however, sulfate reduction produced large sulfide concentrations which...
Tipo: Text
Palavras-chave: Sediment diagenesis; Iron reduction; Sulfate reduction; Deep-sea fans.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00389/50068/52254.pdf

Tiny Is Mighty: Seagrass Beds Have a Large Role in the Export of Organic Material in the Tropical Coastal Zone
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gillis, Lucy G.; Ziegler, Alan D.; Van Oevelen, Dick; Cathalot, Cecile; Herman, Peter M. J.; Wolters, Jan W.; Bouma, Tjeerd J.
Ecosystems in the tropical coastal zone exchange particulate organic matter (POM) with adjacent systems, but differences in this function among ecosystems remain poorly quantified. Seagrass beds are often a relatively small section of this coastal zone, but have a potentially much larger ecological influence than suggested by their surface area. Using stable isotopes as tracers of oceanic, terrestrial, mangrove and seagrass sources, we investigated the origin of particulate organic matter in nine mangrove bays around the island of Phuket (Thailand). We used a linear mixing model based on bulk organic carbon, total nitrogen and delta C-13 and delta N-15 and found that oceanic sources dominated suspended particulate organic matter samples along the...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00242/35335/33926.pdf

The fate of river organic carbon in coastal areas: A study in the Rhone River delta using multiple isotopic (delta C-13, Delta C-14) and organic tracers
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cathalot, Cecile; Rabouille, Christophe; Tisnerat-laborde, N.; Toussaint, Flora; Kerherve, P.; Buscail, R.; Loftis, K.; Sun, M. -y.; Tronczynski, Jacek; Azoury, S.; Lansard, Bruno; Treignier, Claire; Pastor, L.; Tesi, T.
A significant fraction of the global carbon flux to the ocean occurs in River-dominated Ocean Margins (RiOMar) although large uncertainties remain in the cycle of organic matter (OM) in these systems. In particular, the OM sources and residence time have not been well clarified. Surface (0-1 cm) and sub-surface (3-4 cm) sediments and water column particles (bottom and intermediate depth) from the Rhone River delta system were collected in June 2005 and in April 2007 for a multi-proxy study. Lignin phenols, black carbon (BC), proto-kerogen/BC mixture, polycyclic aromatic hydrocarbons (PAHs), carbon stable isotope (delta C-13(OC)), and radiocarbon measurements (delta C-14(OC)) were carried out to characterize the source of sedimentary organic material and to...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00157/26784/25673.pdf

Particulate Matter in Mangrove Forests and Seagrass Beds as a Nitrogen Source in Tropical Coastal Ecosystems
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gillis, Lucy G.; Bouma, Tjeerd J.; Cathalot, Cecile; Ziegler, Alan D.; Herman, Peter M.
We show in laboratory and field investigations that in the short-term seagrasses obtain most of their required nitrogen from the degradation of seagrass leaves, rather than degradation of leaves exported from adjacent mangroves. Mangrove forests at our Thailand site retain the majority of their nutrients, and therefore potentially buffer seagrasses from nutrients.
Tipo: Text
Palavras-chave: Buffering; Mangrove forests; Nitrogen; Outwelling; Particulate organic material; Seagrass beds.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00266/37731/42021.pdf

An Assessment of the Precision and Confidence of Aquatic Eddy Correlation Measurements
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Donis, Daphne; Holtappels, Moritz; Noss, Christian; Cathalot, Cecile; Hancke, Kasper; Polsenaere, Pierre; Wenzhoefer, Frank; Lorke, Andreas; Meysman, Filip J. R.; Glud, Ronnie N.; Mcginnis, Daniel F.
The quantification of benthic fluxes with the aquatic eddy correlation (EC) technique is based on simultaneous measurement of the current velocity and a targeted bottom water parameter (e.g., O2, temperature). High-frequency measurements (64 Hz) are performed at a single point above the seafloor using an acoustic Doppler velocimeter (ADV) and a fast-responding sensor. The advantages of aquatic EC technique are that 1) it is noninvasive, 2) it integrates fluxes over a large area, and 3) it accounts for in situ hydrodynamics. The aquatic EC has gained acceptance as a powerful technique; however, an accurate assessment of the errors introduced by the spatial alignment of velocity and water constituent measurements and by their different response times is...
Tipo: Text
Palavras-chave: Turbulence; Boundary layer; Fluxes; Instrumentation/sensors; Optimization; Experimental design.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38577/37102.pdf

Benthic alkalinity and dissolved inorganic carbon fluxes in the Rh&amp;amp;#244;ne River prodelta generated by decoupled aerobic and anaerobic processes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Rassmann, Jens; Eitel, Eryn M.; Lansard, Bruno; Cathalot, Cecile; Brandily, Christophe; Taillefert, Martial; Rabouille, Christophe.
Estuarine regions are generally considered a major source of atmospheric CO2, as a result of the high organic carbon (OC) mineralization rates in their water column and sediments. Despite this, the intensity of anaerobic respiration processes in the sediments tempered by the reoxidation of reduced metabolites near the sediment–water interface controls the flux of benthic alkalinity. This alkalinity may partially buffer metabolic CO2 generated by benthic OC respiration in sediments. Thus, sediments with high anaerobic respiration rates could contribute less to local acidification than previously thought. In this study, a benthic chamber was deployed in the Rhône River prodelta and the adjacent continental shelf (Gulf of Lion, northwestern Mediterranean) in...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00600/71163/69492.pdf

Deep cold-water coral ecosystems in the Brittany submarine canyons (Northeast Atlantic): Hydrodynamics, particle supply, respiration, and carbon cycling
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Khripounoff, Alexis; Caprais, Jean-claude; Le Bruchec, Julie; Rodier, Philippe; Noel, Philippe; Cathalot, Cecile.
The submarine canyons of the Brittany continental slope (Bay of Biscay–Northeast Atlantic) were studied to describe the conditions in which cold-water corals occur in these areas and their consequences for coral metabolism. Near-bottom current, oxygen, temperature, and particle flux, simultaneously measured for 2 yr at 850 m depth, revealed by spectral analysis the presence of several frequencies with a dominant semidiurnal tidal cycle and a current direction determined exclusively by the canyon topography. Sediment trap data also showed a seasonal input of material with a large peak of particles and carbon fluxes at the end of winter. Daily particle and carbon fluxes at 20 m above the bottom were 2.49 g m−2 d−1 and 20 mg C m−2 d−1, respectively. At the...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00173/28380/26695.pdf

A comparison of in situ vs. ex situ filtration methods on the assessment of dissolved and particulate metals at hydrothermal vents
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cotte, Laura; Waeles, Mathieu; Pernet-coudrier, Benoit; Sarradin, Pierre-marie; Cathalot, Cecile; Riso, Ricardo D.
The objective of this study was to assess the impact of the filtration method (in situ vs. ex situ) on the dissolved/particulate partitioning of 12 elements in hydrothermal samples collected from the Lucky Strike vent field (Mid-Atlantic Ridge; MAR). To do so, dissolved ( &lt;0.45 mu m) and particulate Mg, Li, Mn, U, V, As, Ba, Fe, Zn, Cd, Pb and Cu were measured using different techniques (HR-ICP-MS, ICP-AES and CCSA). Using in situ filtration as a baseline, we showed that ex situ filtration (on-board and on shore after freezing) resulted in an underestimation of the dissolved pool, which was counterbalanced by an overestimation of the particulate pool for almost all the elements studied. We also showed that on-board filtration was acceptable for the...
Tipo: Text
Palavras-chave: Metal; Hydrothermal vent; Dissolved; Particulate; Filtration method.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00298/40970/42656.pdf

Processes Driving Iron and Manganese Dispersal From the TAG Hydrothermal Plume (Mid-Atlantic Ridge): Results From a GEOTRACES Process Study
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: González-santana, David; Planquette, Helene; Cheize, Marie; Whitby, Hannah; Gourain, Arthur; Holmes, Thomas; Guyader, Vivien; Cathalot, Cecile; Pelleter, Ewan; Fouquet, Yves; Sarthou, Geraldine.
Hydrothermal vents are a recognized source of trace elements to the ocean inventory. Nevertheless, the contribution of slow-spreading ridges remains poorly resolved. To address this, high-resolution dissolved (&lt;0.45 μm) iron (dFe) and manganese (dMn) samples were collected during the GEOTRACES HERMINE GApr07 process study at the Mid Atlantic Ridge. Samples were collected at nine stations, from the TAG vent site to 75 km south-southwest following the neutrally buoyant plume. Concentrations of dMn and dFe ranged from 71 ± 6 and 51 ± 2 nmol kg–1 right above the vent site to 0.43 ± 0.01 and 1.56 ± 0.02 nmol kg–1 at the most distal station, respectively. Using a 5-box model coupled with our data, we show that as the plume traveled away from the vent,...
Tipo: Text
Palavras-chave: Iron; Manganese; Hydrothermal; TAG; Mid Atlantic Ridge; GEOTRACES.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00643/75530/76431.pdf

Structure of the Demerara passive-transform margin and associated sedimentary processes. Initial results from the IGUANES cruise
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Loncke, L.; Maillard, A.; Basile, C.; Roest, Walter; Bayon, Germain; Gaullier, V.; Pattier, France; Mercier De Lépinay, Marion; Grall, Celine; Droz, L.; Marsset, Tania; Giresse, P.; Caprais, Jean-claude; Cathalot, Cecile; Graindorge, D.; Heuret, A.; Lebrun, J. F.; Bermell, Sylvain; Marcaillou, B.; Sotin, C.; Hebert, B.; Patriat, Martin; Bassetti, M. A.; Tallobre, Cedric; Buscail, R.; Durrieu De Madron, X.; Bourrin, F.
he IGUANES cruise took place in May 2013 on the R/V L'Atalante along the Demerara passive transform margin off French Guiana and Surinam. Seismic, multibeam and chirp acquisitions were made. Piston cores were collected for pore geochemistry and sedimentology. A mooring was deployed on the sea-bottom for 10 months (temperature, salinity, turbidity and current measurements). This new dataset highlights the lateral variability of the 350 km-long Guiana–Surinam transform margin due to the presence of a releasing bend between two transform segments. The adjacent Demerara Plateau is affected by a 350 km-long giant slide complex. This complex initiated in Cretaceous times and was regularly reactivated until recent times. Since the Miocene, contourite processes...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00428/53942/55285.pdf

Endogenous versus exogenous factors: What matters for vent mussel communities?
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Sarrazin, Jozee; Portail, Marie; Legrand, E.; Cathalot, Cecile; Laes, Agathe; Lahaye, Noe; Sarradin, Pierre-marie; Husson, Berengere.
The factors influencing the structure of hydrothermal communities are not necessarily similar across geographical regions and vent fields. In the present study, we explore the role of environmental conditions on vent community structure at local and regional spatial scales, focusing on the assemblages dominated by the engineer species Bathymodiolus azoricus. Their presence in several vent fields on the northern Mid-Atlantic Ridge (MAR) represents a unique opportunity to compare their associated fauna and to better understand large-scale biodiversity patterns. Two types of factors were considered: exogenous ones such as the presence of biogeographical barriers, depth, and distance between sites, and those linked to the intrinsic characteristics of each...
Tipo: Text
Palavras-chave: Intra-field variability; Inter-field variability; Hydrothermal fauna; Abiotic factors; Diversity measures; Macrofauna; Meiofauna; Environmental drivers; Community structure; Habitats.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00615/72661/71671.pdf

On the nature of dissolved copper ligands in the early buoyant plume of hydrothermal vents
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cotte, Laura; Omanovic, Dario; Waeles, Mathieu; Laes, Agathe; Cathalot, Cecile; Sarradin, Pierre-marie; Riso, Ricardo D.
Environmental contextCopper released by deep-sea hydrothermal vents has been recognised to be partly stabilised against precipitation by its complexation with strong Cu binding ligands. Yet, the sources and nature of these compounds in such environments are still not fully understood. This study shows that the Cu ligands detected are hydrothermally sourced and could be mainly inorganic sulfur species. AbstractThe apparent speciation of Cu in the early buoyant plume of two black smokers (Aisics and Y3) from the hydrothermal vent field Lucky Strike (Mid-Atlantic Ridge) was investigated using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-AdCSV). We have assessed the apparent Cu-binding ligand concentration ([L]) and the...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00444/55558/57208.pdf

A new device to follow temporal variations of oxygen demand in deltaic sediments: the LSCE benthic station
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Toussaint, Flora; Rabouille, Christophe; Cathalot, Cecile; Bombled, Bruno; Abchiche, Abdel; Aouji, Oualid; Buchholtz, Gilles; Clemencon, Aurelien; Geyskens, Nicolas; Repecaud, Michel; Pairaud, Ivane; Verney, Romaric; Tisnerat-laborde, Nadine.
A new benthic station equipped with oxygen microelectrodes and environmental sensors was developed by Laboratoire des Sciences du Climat et de L’Environnement (LSCE) and Division Technique of the Institut National des Sciences de L’Univers (DT-INSU) to perform in situ time series monitoring of sediment oxygen demand, linked to the mineralization of organic matter. The time series typically cover periods of 2-3 months, with a base frequency of 1 set of oxygen profiles per day. The profiling head assessed the lateral heterogeneity of the sediment oxygen demand at the beginning of the time series over a 0.8-m long rectangle to discriminate spatial and temporal variability. A continuous recalibration is performed using a moored oxygen optode anchored to the...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00230/34126/32597.pdf

Sulfate minerals control dissolved rare earth element flux and Nd isotope signature of buoyant hydrothermal plume (EMSO-Azores, 37°N Mid-Atlantic Ridge)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Chavagnac, Valerie; Ali, Hassan Saleban; Jeandel, Catherine; Leleu, Thomas; Destrigneville, Christine; Castillo, Alain; Cotte, Laura; Waeles, Mathieu; Cathalot, Cecile; Laes, Agathe; Pelleter, Ewan; Nonnotte, Philippe; Sarradin, Pierre-marie; Cannat, Mathilde.
While hydrothermal vents are now thought to be a major source of dissolved iron to the oceans, they have always been considered to be a sink for the dissolved rare-earth elements (DREEs). However, true dissolved REE observations in hydrothermal plumes are still lacking. Here we report for the first time the DREE concentrations and neodymium isotopic compositions (DεNd) of buoyant hydrothermal fluids at Lucky Strike (Mid-Atlantic Ridge). We find that 27 to 62% of total hydrothermal DREEs are rapidly scavenged by anhydrite precipitation at the onset of buoyant plume formation. After this initial loss, all DREEs behave quasi-conservatively within the buoyant plume. Dissolved phase εNd (DεNd) in the evolving plume are identical to black smoker DεNd of +9.0 and...
Tipo: Text
Palavras-chave: Black smokers; Rare earth elements; Neodymium isotopes; Hydrothermal; Sulfate minerals; EMSO-Azores.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00456/56733/58511.pdf

Long-Term In Situ Survey of Reactive Iron Concentrations at the EMSO-Azores Observatory
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Laes-huon, Agathe; Cathalot, Cecile; Legrand, Julien; Tanguy, Virginie; Sarradin, Pierre-marie.
A study of the temporal dynamics of iron concentrations and temperature on a faunal assemblage at the Lucky Strike vent was performed using the Tempo ecological module at the EMSO-Azores deep-sea observatory. The CHEMINI in situ analyzer was implemented on this structure to determine reactive iron concentrations in unfiltered seawater samples along with a temperature probe. Stability tests were performed on the CHEMINI analyzer before deployment (optical module, hyperbaric tests, and deep-sea calibration) for long-term in situ analysis of reactive iron (six months, 2013–2014) at the Tour Eiffel active edifice. Recorded daily, the in situ standard (25 \mu mol.L {}^{-1} ) showed excellent reproducibility (1.07%, n=522 ), confirming satisfactory analytical...
Tipo: Text
Palavras-chave: Deep-sea observatory; Hydrothermal vent; In situ chemical analyzer; Iron; Monitoring the Mid-Atlantic Ridge (MoMAR).
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00342/45275/46432.pdf

On the early fate of hydrothermal iron at deep-sea vents: A reassessment after in situ filtration
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Waeles, Mathieu; Cotte, Laura; Pernet-coudrier, Benoit; Chavagnac, V.; Cathalot, Cecile; Leleu, T.; Laes-huon, Agathe; Perhirin, Antoine; Riso, R. D.; Sarradin, Pierre-marie.
Deep-sea hydrothermal venting is now recognized as a major source of iron (Fe), an essential trace element that controls marine productivity. However, the reactions occurring during dispersal from buoyant plumes to neutrally buoyant hydrothermal plumes are still poorly constrained. Here we report for the first time on the dissolved-particulate partition of Fe after in situ filtration at the early stage of mixing at different hydrothermal discharges, i.e., Lucky Strike (37 degrees N), TAG (26 degrees N), and Snakepit (23 degrees N) on the Mid-Atlantic Ridge. We found that hydrothermal iron is almost completely preserved (&gt;90%) in the dissolved fraction, arguing for low iron-bearing sulfide precipitation of iron in basalt-hosted systems with low Fe:H2S...
Tipo: Text
Palavras-chave: Hydrothermal; Iron; Sulfide; Venting; Filtration; Precipitation.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00388/49944/50522.pdf

Cold-water coral reefs and adjacent sponge grounds: hotspots of benthic respiration and organic carbon cycling in the deep sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cathalot, Cecile; Van Oevelen, Dick; Cox, Tom J.s.; Kutti, Tina; Lavaleye, Marc S. S.; Duineveld, Gca; Meysman, Filip J. R.
Cold-water coral reefs and adjacent sponge grounds are distributed widely in the deep ocean, where only a small fraction of the surface productivity reaches the seafloor as detritus. It remains elusive how these hotspots of biodiversity can thrive in such a food-limited environment, as data on energy flow and organic carbon utilization are critically lacking. Here we report in situ community respiration rates for cold-water coral and sponge ecosystems obtained by the non-invasive aquatic Eddy Correlation technique. Oxygen uptake rates over coral reefs and adjacent sponge grounds in the Træna Coral Field (Norway) were 9–20 times higher than those of the surrounding soft sediments. These high respiration rates indicate strong organic matter consumption, and...
Tipo: Text
Palavras-chave: Deep-seaecosystems; Cold-watercorals; Sponges; Respiration; Energyflow.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00275/38574/37099.pdf

Origin of an enigmatic regional Mio-Pliocene unconformity on the Demerara plateau
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Pattier, France; Loncke, L.; Imbert, Patrice; Gaullier, V.; Basile, C.; Maillard, Alexandre; Roest, Walter; Patriat, Martin; Vendeville, B. C.; Marsset, Tania; Bayon, Germain; Cathalot, Cecile; Caprais, Jean-claude; Bermell, Sylvain; Sotin, Christine; Hebert, Bertil; Mercier De Lepinay, Marion; Lebrun, J. F.; Marcaillou, B.; Heuret, A.; Droz, Laurence; Graindorge, David; Poetisi, E.; Berrenstein, H.
The Demerara plateau, located offshore French Guiana and Suriname, is part of a passive transform continental margin particularly prone to develop slope instabilities, probably in relation to the presence of a free distal border along its steep continental slope. Slope failure occurred at different periods (Cretaceous to Neogene) and shows an overall retrogressive evolution through time. Upslope these failure headscarp, an enigmatic regional MioPliocene unconformity has been discovered through the interpretation of new academic and industrial datasets. The aim of this work is to describe and understand the origin of this surface. Our analysis shows that this unconformity is made of a series of valleys that cross-cut sedimentary strata. Each one of these...
Tipo: Text
Palavras-chave: Unconformity; Hydrate pockmark; Slide; Contourite; Valley; Canyon; Demerara plateau.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00271/38193/36735.pdf