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| Registros recuperados: 42 | |
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| Bajjouk, Touria; Rochette, Sebastien; Ehrhold, Axel; Cordier, Celine; Laurans, Martial; Tourolle, Julie; Hamdi, Anouar; Tourolle, Julie; Gaffet, Jean-dominique; Caisey, Xavier; Vasquez, Mickael; Populus, Jacques. |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00280/39159/37722.pdf |
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| Baltzer, Agnes; Reynaud, Marine; Ehrhold, Axel; Fournier, Jerome; Cordier, Celine; Clouet, Helene. |
| About a decade ago, a large field of pockmarks, covering an overall area of 36 km(2) was discovered in water depths of < 30m in the central part of the Bay of Concarneau (Southern Brittany, France). This field, composed of features from 5 m to 35 m in diameter and < 1 m in depth, is characterized by unusual high densities of pockmarks, up to 5840 per square kilometre. Geophysical data correlated with sedimentary samples acquired in 2005 and 2009 show that pockmarks and their immediate surroundings are associated with dense tubes benches cover, built by a filter-feeding amphipod: Haploops nirae, forming original benthic communities. Two complementary surveys were carried out in April 2011 (Pock and Ploops) and April 2014 (Pock and Tide), on the... |
| Tipo: Text |
Palavras-chave: Géophysique; Marée; Failles; Gaz; Geophysics; Pockmarks; Tide; Turbidity; Gas; Chimneys pipes; Concarneau. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00410/52107/52938.pdf |
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| Delebecq, Gaspard; Schmidt, Sabine; Ehrhold, Axel; Latimier, Marie; Siano, Raffaele. |
| The biological processes involved in the preservation, viability, and revival of long‐term dormant dinoflagellate cysts buried in sediments remain unknown. Based on studies of plant seed physiology, we tested whether the revival of ancient cysts preserved in century‐old sediments from the Bay of Brest (France) could be stimulated by melatonin and gibberellic acid, two molecules commonly used in seed priming. Dinoflagellates were revived from sediments dated to approximately 150 years ago (156 ± 27, 32 cm depth), extending the known record age of cyst viability previously established as around one century. A culture suspension of sediments mixed with melatonin and gibberellic acid solutions as biostimulants exhibited germination of 11 dinoflagellate taxa... |
| Tipo: Text |
Palavras-chave: Alexandrium; Cyst; Dinoflagellate; Gibberellic acid; Melatonin; Paleoecology; Priming; Scrippsiella; Resurrection ecology. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00627/73960/73321.pdf |
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| Dupré, Stephanie; Loubrieu, Benoit; Pierre, C.; Scalabrin, Carla; Guerin, Charline; Ehrhold, Axel; Ogor, Andre; Gautier, Emeric; Ruffine, Livio; Biville, Romain; Saout, Johan; Breton, C; Floodpage, J.; Lescanne, M.. |
| A few thousand (2612) seeps are releasing microbial methane bubbles from the seafloor at the Aquitaine Shelf edge (Bay of Biscay) at shallow water depths (140‐220 m). This methane contributes to the formation of meter‐scale subcircular carbonate structures, which are (sub‐)outcropping over 375 km2. Based on in situ flow rate measurements and acoustic data, and assuming steady and continuous fluxes over time, the methane entering the water column is estimated to 144 Mg/yr. Microbial methane circulation has been on‐going for at least a few thousand years. This discovery highlights the importance of microbial methane generation, disconnected from deep thermogenic sources and gas hydrates, at continental shelves. The shelf edge may be viewed as a focus area... |
| Tipo: Text |
Palavras-chave: Microbial methane; Continental shelf; Fluid emissions; High‐resolution acoustics; Aquitaine Margin; Methane‐derived authigenic carbonates. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/72982/72057.pdf |
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| Durand, M.; Mojtahid, M.; Maillet, G. M.; Proust, J. -n.; Lehay, D.; Ehrhold, Axel; Barre, A.; Howa, H.. |
| We used sedimentological and foraminiferal characteristics of four sedimentary cores, supported by paleogeographical and historical data, to reconstruct the depositional history of the inner Loire estuary (Near Saint-Nazaire, France) and the response of benthic foraminifera to the mid- to late-Holocene marine flooding of the incised valley. These were further used to evaluate the consequent changes in estuarine morphological and hydro-sedimentary patterns during this time period. Our results described significant changes in hydro-sedimentary dynamics over the past ~ 6 kyrs BP. At our location, these changes expressed the combined influence of marine (e.g., tide, storm waves) and fluvial dynamics (e.g., floods), which are linked, on a broader scale, to... |
| Tipo: Text |
Palavras-chave: Macrotidal estuary; Mid-latitude estuary; Holocene paleoenvironment; Estuarine facies; Benthic foraminifera; Sea-level change. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00347/45849/45511.pdf |
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| Dutertre, Mickael; Grall, Jacques; Ehrhold, Axel; Hamon, Dominique. |
| This study used a large spatial scale approach in order to better quantify the relationships between maerl bed structure and a selection of potentially forcing physical factors. Data on maerl bed structure and morpho-sedimentary characteristics were obtained from recent oceanographic surveys using underwater video recording and grab sampling. Considering the difficulties in carrying out real-time monitoring of highly variable hydrodynamic and physicochemical factors, these were generated by three-dimensional numerical models with high spatial and temporal resolution. The BIOENV procedure indicated that variation in the percentage cover of thalli can best be explained (correlation = 0.76) by a combination of annual mean salinity, annual mean nitrate... |
| Tipo: Text |
Palavras-chave: Benthic habitats; Brittany; Environmental factors; Estuary; Large spatial scale; Maerl. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00280/39089/37816.pdf |
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| Ehrhold, Axel. |
| La baie de Morlaix, fermée par l’île de Batz à l’ouest, les falaises de Primel-Trégastel à l’est, et l’archipel de la Méloine au nord, est un des joyaux de la côte bretonne appréciée pour sa diversité biologique mais beaucoup moins connue par ses particularités géologiques. Sa morphologie sous-marine est une sorte de labyrinthe, composé de nombreux îlots et hauts-fonds, à l’origine d’une mosaïque de provinces sédimentaires où se confrontent à chaque marée, courants et sédiments. Cette synthèse (au format papier et numérique) regroupe les travaux menés depuis une dizaine d’années par l’Ifremer sur les fonds de cette région. Elle répond ainsi à la préoccupation d’une large communauté curieuse de son environnement : la morphologie du littoral, la dynamique et... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00285/39603/38097.pdf |
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| Ehrhold, Axel; Auffret, Jean-paul. |
| Grain size trends in relation to net sediment transport pathways are examined, using sorne cornmonly-used grain size pararneters. The results of the model are compared with the net sediment transport pathways established on the basis of the bedfonn asymmetry. The 3 types of trends are calculated using an increasing characteristic distance and differents grids of seabed sediment samples. lt is shown that : (1) the characteristic distance defined by Gao et Collins (maximum spatial sampling interval) changes with these two factors to a maximal value; (2) in an heterogeneous sedimentary environment, the correlations between calculated vectors and observed transport pathways are better by using sand size distributions and (3) the residual pattern rises to sixty... |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00285/39620/38111.pdf |
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| Ehrhold, Axel; Chevalier, Claire; Alix, Anne-sophie; Autret, Elodie; Caisey, Xavier; Drussel, Benjamin; Gaffet, Jean-dominique; Hamon, Dominique; Houlgatte, Eric; Pluquet, Fabrice; Biscara, Laurie; Choisnet, Justine; Bajjouk, Touria. |
| In 2000 Ifremer launched and coordinated the development of a monitoring strategy for the REBENT network (REseau BENThique) in order to assess the aftermath of the “Erika” oil spill which took place in December 1999. Its aim is to provide consistent baseline knowledge on coastal benthic habitats, as well as to develop a monitoring tool that detects changes at various spatial and temporal scales. Sector-based seabed habitat mapping in shallow water (< 50 m deep), is currently being conducted throughout Brittany's coastal waters using a combination of geoacoustic marine systems together with ground-truthing using biological grab sampling and seabed observations. Due to the extended area, the overlap of soft and rocky bottoms, and contrasting hydrological... |
| Tipo: Text |
Palavras-chave: Rebent; Trégor-Goëlo; Bréhat; Cartographie d’habitats; Sonar latéral; Macrofaune benthique; Peuplements; Crépidule; Maërl; Sédiments; Morphologie; Dynamique sédimentaire; Rebent; Trégor-Goëlo; Bréhat archipelago; Marine habitat mapping; Sidescan sonar; Benthic macrofauna; Communities; Crepidula bed; Maerl; Sediment; Morphology; Bedload transpor. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00280/39161/37724.pdf |
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| Ehrhold, Axel; Cordier, Celine; Pluquet, Fabrice; Alix, Anne-sophie; Monpert, Coralie; Autret, Elodie; Hamon, Dominique. |
| Les besoins d'inventaires et de suivis des habitats benthiques côtiers, de même que la nécessité de mieux comprendre leur fonctionnement, conduisent depuis plusieurs années à mettre en place des actions à différentes échelles d'observation spatiales et temporelles sur l’ensemble des façades métropolitaines. L’application du Réseau Benthique au pilote breton en est une parfaite illustration. Le Rebent a ainsi soutenu dès 2001 le projet d’une embarcation spécialisée, destinée à relayer dans la frange littorale les moyens acoustiques mis en oeuvre sur les navires côtiers plus au large, et capable d’assurer une investigation des fonds sur de grandes superficies, avec un fort pouvoir de résolution. Ce projet de vedette porté par l’Ifremer a été rendu possible... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00283/39440/37888.pdf |
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| Registros recuperados: 42 | |
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