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| Registros recuperados: 42 | |
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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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| Gregoire, Gwendoline; Le Roy, Pascal; Ehrhold, Axel; Jouet, Gwenael; Garlan, Thierry. |
| This study details the sedimentary infilling of an original tidal-dominated estuary system during the final stage of the last marine transgression. The Bay of Brest is confined and connects the rivers Elorn and Aulne, to the sea of Iroise by a narrow strait encasing a well preserved paleo-channel. The compilation of high- and very-high-resolution bathymetric and seismic data, constrained by sediments datations, allows us to classify the paleo-morphology of the bay into three stepped domains: the paleo-valley floor surrounded by fluvial terraces, the central plateau, and the shallow embayments. Taking into account the main factors controlling the infilling, including sea-level rise, substratum morphology, and hydrodynamics, the stratigraphic scheme of the... |
| Tipo: Text |
Palavras-chave: Tide-dominated estuary; Incised-valley; Holocene infill; Seismic stratigraphy; Estuarine processes; Bay of Brest. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00358/46968/46883.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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| Hamon, Dominique; Ehrhold, Axel; Houlgatte, Eric; Kerdoncuff, Julien; Gaffet, Jean-dominique; Caisey, Xavier; Alix, Anne-sophie; Oger-jeanneret, Helene. |
| Poster présenté aux Journées REBENT Brest les 13 et 14/10/2011 (2ème atelier de restitution Rebent Bretagne. Dans le cadre du programme de surveillance DCE, et en lien avec le projet REBENT, il a été entrepris en 2008-2009 de cartographier et de caractériser les principaux bancs de maërl distribués dans 9 masses d'eaux autour de la Bretagne, et faisant l'objet pour la plupart d'un suivi annuel de leur biodiversité, assuré par l'IUEM (LEMAR). |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00042/15275/12631.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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| Gandois, Henri; Stephan, Pierre; Cuisnier, David; Hulot, Olivia; Ehrhold, Axel; Paul, Marine; Le Dantec, Nicolas; Franzetti, Marcaurelio. |
| This reports on a project that combined evidence gleaned from aerial photographs, place-names, interviews, topography, LIDAR data, and sonar bathymetry to locate stone tidal fish weirs in the Molene Archipelago. The results were verified by diver and pedestrian visual surveys. Models of Holocene sea-level change allowed a group of possibly Late Mesolithic-Early Neolithic weirs to be recognized, with a second group broadly dated to the later Neolithic-Early Bronze Age. The construction of these long megalithic structures is compared to the funerary monuments for which the Molene Archipelago is well known, in terms of technique, cost, and societal organization. |
| Tipo: Text |
Palavras-chave: Tidal weirs fish traps Mol<; Bold>; E<; /bold>; Ne Archipelago megalithic constructions sea-level change Mesolithic Neolithic. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00430/54208/55907.pdf |
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| Lambert, Clément; Penaud, A.; Vidal, Marie-odile; Gandini, C.; Labeyrie, L.; Chauvaud, Laurent; Ehrhold, Axel. |
| The Holocene period (last 11,700 years BP) has been marked by significant climate variability over decadal to millennial timescales. The underlying mechanisms are still being debated, despite ocean–atmosphere–land connections put forward in many paleo-studies. Among the main drivers, involving a cluster of spectral signatures and shaping the climate of north-western Europe, are solar activity, the North Atlantic Oscillation (NAO) varying atmospheric regimes and North Atlantic oceanic gyre dynamics. Over the last 2500 years BP, paleo-environmental signals have been strongly affected by anthropogenic activities through deforestation and land use for crops, grazing, habitations, or access to resources. Palynological proxies (especially pollen grains and... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00665/77715/79803.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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| Gregoire, Gwendoline; Ehrhold, Axel; Le Roy, Pascal; Jouet, Gwenael; Garlan, Thierry. |
| Long-studied with respect to its sedimentological features (1897), the Bay of Brest (Western Britanny, France) is a textbook example of a tide-dominated estuary. Characterised by macrotidal conditions, this estuary system is sheltered from the open sea (Iroise Sea) by a narrow strait that partitions the wave tide influences and continental/marine inputs. Sediments are supplied to the bay both by rivers (the Aulne and Elorn rivers) and by marine tidal currents. This study presents new analyses of detailed facies and morphological patterns, based on the integration of multisource data compiling seabed sampling, swath and LIDAR bathymetry, and backscatter imagery. The Main Map, at a scale of 1:90,000, contains (1) a sedimentological distribution using the... |
| Tipo: Text |
Palavras-chave: Morpho-sedimentological cartography; Tide-dominated; Estuary system; Estuarine sedimentation; Backscatter imagery; Bay of Brest. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00334/44492/44224.pdf |
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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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| 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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| Registros recuperados: 42 | |
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