Extrait de : Le Globe trotter, n°166 pp214-216
Résumé : Article 3 p. 1 gravure 7 photos
Siècle(s) traité(s) : 20
Droits : Domaine public
Provenance : ORkidé|Fonds privé Pierre Rostan
Permalien : http://www.manioc.org/patrimon/ORK12166
ORK12166

Éditeur(s) : La Habana : Imprenta "El siglo XX"

Droits : Domaine public
Provenance : Institut des Hautes Études de l'Amérique latine, Bibliothèque Pierre-Monbeig
Permalien : http://www.manioc.org/patrimon/IHE14020
IHE14020

Éditeur(s) : Elsevier Science Bv
Résumé : Fluid escape structures on the Nile Deep Sea Fan were investigated during the MEDIFLUX MIMES expedition in 2004. Mud volcanoes, pockmarks and authigenic carbonate structures were surveyed for the first time with a high-resolution deep-towed 75 kHz sidescan sonar and a 2-8 kHz Chirp sediment echosounder. In combination with existing multibeam bathymetry and detailed seafloor in situ geological observations, these new data allowed detailed seep analyses. About 60 gas flares were detected acoustically in the water column from the sidescan sonar raw data at water depths from 770 to 1700 m. These gas flares coincide at the seabed with 1) the centres of the mud volcanoes where mud is also extruded, 2) the borders of the mud volcanoes where the emitted gases contribute to the precipitation of authigenic carbonates, and 3) to the edges of broad sheets of authigenic carbonates. Subsurface sediments are commonly disturbed by ascending fluids throughout the delta, with an abundance of seep-related carbonate structures on the seafloor. The feeder channels below mud volcanoes, similar to the gas conduits below the widespread carbonate crust structures and pockmarks, are relatively narrow and, for the vast majority of them, do not exceed a few metres in diameter. The seeps on the Nile Deep Sea Fan clearly follow lineations on the seafloor that we can relate to faults. (C) 2010 Elsevier B.V. All rights reserved.
Marine Geology (0025-3227) (Elsevier Science Bv), 2010-09 , Vol. 275 , N. 1-4 , P. 1-19

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00013/12457/9766.pdf
DOI:10.1016/j.margeo.2010.04.003
http://archimer.ifremer.fr/doc/00013/12457/

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
Microbathymetry data, in situ observations, and sampling along the 13°20′N and 13°20′N oceanic core complexes (OCCs) reveal mechanisms of detachment fault denudation at the seafloor, links between tectonic extension and mass wasting, and expose the nature of corrugations, ubiquitous at OCCs. In the initial stages of detachment faulting and high-angle fault, scarps show extensive mass wasting that reduces their slope. Flexural rotation further lowers scarp slope, hinders mass wasting, resulting in morphologically complex chaotic terrain between the breakaway and the denuded corrugated surface. Extension and drag along the fault plane uplifts a wedge of hangingwall material (apron). The detachment surface emerges along a continuous moat that sheds rocks and covers it with unconsolidated rubble, while local slumping emplaces rubble ridges overlying corrugations. The detachment fault zone is a set of anostomosed slip planes, elongated in the along-extension direction. Slip planes bind fault rock bodies defining the corrugations observed in microbathymetry and sonar. Fault planes with extension-parallel stria are exposed along corrugation flanks, where the rubble cover is shed. Detachment fault rocks are primarily basalt fault breccia at 13°20′N OCC, and gabbro and peridotite at 13°30′N, demonstrating that brittle strain localization in shallow lithosphere form corrugations, regardless of lithologies in the detachment zone. Finally, faulting and volcanism dismember the 13°30′N OCC, with widespread present and past hydrothermal activity (Semenov fields), while the Irinovskoe hydrothermal field at the 13°20′N core complex suggests a magmatic source within the footwall. These results confirm the ubiquitous relationship between hydrothermal activity and oceanic detachment formation and evolution.
ISSN: 1525-2027

hal-01571973
https://hal.archives-ouvertes.fr/hal-01571973
https://hal.archives-ouvertes.fr/hal-01571973v2/document
https://hal.archives-ouvertes.fr/hal-01571973/file/Escart-n_et_al-2017-Geochemistry%2C_Geophysics%2C_Geosystems.pdf
DOI : 10.1002/2016GC006775

Éditeur(s) : EDP Sciences
Résumé : A population of the invasive slipper limpet (Crepidula fornicata) has been spreading in the Bay of Mont-Saint-Michel (Western English Channel) for 40 years. Sidescan sonar, underwater video and quantitative sampling were conducted in 1996 and 2004 to document the widening geographic spread of the species over the bay. The limpet population grew by 50% during this period, to reach a fresh biomass of about 150 000 t. This local study analyses causes and effects of the spread and provides a typical example of the limpet spreading process. This population increase has significant effects on the environment in the most densely colonized area (modification to the sediment and biodiversity), leading to the emergence of a new benthic community. Anthropic dredging activities are among the causative factors of the spread but are also adversely affected by the invasion.
Depuis 40 ans, la population de crépidules (Crepidula fornicata) prolifère en baie du Mont Saint-Michel (Manche Ouest). Deux études réalisées en 1996 et 2004 ont permis de cartographier et d'estimer le stock de la population grâce à des moyens similaires : sonar à balayage latéral, vidéo sous-marine et prélèvements quantitatifs à la benne. Durant cet intervalle de temps, la biomasse a augmenté de 50 % pour atteindre 150 000 t dans la baie en 2004. Cette étude comparative a permis d'analyser les causes et les effets d'une telle prolifération et d'en montrer le processus général. Dans les secteurs fortement colonisés, les effets sur l'environnement sont particulièrement néfastes (modification du sédiment et de la biodiversité) et aboutissent à une nouvelle communauté benthique. Les activités de pêche aux engins traînants (dragues et chaluts) sont à la fois les principales responsables et les victimes de cette prolifération.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2009 , Vol. 22 , N. 1 , P. 11-19

Droits : 2009 EDP Sciences
http://archimer.ifremer.fr/doc/2009/publication-6351.pdf
DOI:10.1051/alr/2009004
http://archimer.ifremer.fr/doc/00000/6351/

Éditeur(s) : Gauthier-villars
Résumé : During the Kanaut cruise of the submersible Nautile and its mothership Le-Nadir (15 November-16 December 1992), one dive was devoted to the detailed study of a specific area of the neovolcanic ridge of the MAR around 29-degrees-06'N and 43-degrees-11'W. This study emphasizes the importance of the juxtaposition and the stacking of hundreds of small volcanoes in the construction of a neovolcanic ridge and confirms the general observation made from multibeam and side-scan sonar data. The very large magnetic anomaly associated with these massifs favours an extreme freshness.
Lors de la campagne Kanaut (15 novembre-16 décembre 1992) du Nautile et de son navire support Le-Nadir, une plongée a été consacrée B l'étude détaille d'un secteur de la ride néovalcanique de l'axe de la dorsale médio-Atlantique autour de 29"06" et 43"ll'W. Cette étude permet de souligner le rôle prépondérant que jouent les centaines de petits édifices volcaniques dans la construction de la ride néovolcanique, par leur juxtaposition et leur superposition. Ceci confirme et affine les observations faites B partir des données des sondeurs multifaisceaux et les sonars latéraux. La très forte anomalie magnétique associé B ces édifices penche en faveur de leur extrème fraicheur.
Comptes Rendus de l'Academie des Sciences Serie II (1251-8069) (Gauthier-villars), 1993-05 , Vol. 316 , N. 10 , P. 1415-1422

Droits : Académie des Sciences
http://archimer.ifremer.fr/doc/00183/29475/27887.pdf
http://archimer.ifremer.fr/doc/00183/29475/

Éditeur(s) : HAL CCSD Wiley
Résumé : SUBSURF
International audience
Similarity of form between subaerial and submarine landscapes affected by erosion could suggest similarities in the process of erosion, such as by runoff and sedimentary flows, respectively. On the other hand, if aspects of form vary, its characteristics may be used to identify the environmental origin of erosion. Towards these goals, this contribution addresses the morphology of submarine volcanoes (seamounts) with widely differing histories of erosion. One set from the Pacific Ocean never exposed above sea level includes Cretaceous-age seamounts near Hawai'i (including Apu'upu'u Seamount), two seamounts of < 3 Ma in age near a mid-ocean ridge and the 11-4 Ma Jasper Seamount. These seamounts are all isolated from continents and hence from any erosion associated with mass wasting of unstable terrigenous deposits. In such isolated submarine environments, surfaces erode slowly from in situ weathering, mass wasting and scouring by sedimentary flows initiated by slope failure in pelagic or bedrock materials. The Pacific seamounts are compared with Valencia Seamount in the western Mediterranean, exposed subaerially for 100-400 k.y. during the Messinian Salinity Crisis before 5 Ma. Multibeam and deeply towed sidescan sonar data of Valencia Seamount reveal features typical of subaerial erosion of volcanic islands, such as canyons and relatively uneroded sectors (planezes) between them. Using a simple topographical reconstruction, the apparent erosion depth typically reaches 100 m within canyons and up to 180 m in places. Whereas the younger Pacific seamounts do not show these erosional features, the much older Cretaceous seamounts do have channels, which in one example suggests up to 200 m of incision. Both Valencia and Apu'upu'u seamounts have channel longitudinal profiles that are steep and typically linear to concave upwards. The erosion depth of Apu'upu'u Seamount is significant, despite the seamount's persistent submarine environment, because of its greater age, steeper flanks and greater contributing areas to channels compared with Valencia Seamount. These results illustrate that the channel morphology resulting from submarine erosion can become similar to that produced by subaerial erosion given sufficient time.
ISSN: 0950-091X

hal-00411425
https://hal.archives-ouvertes.fr/hal-00411425
DOI : 10.1111/j.1365-2117.2008.00355.x

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
This contribution is an attempt to present a self-contained and comprehensive survey of the mathematics and physics of material behavior of rocks in terms of texture and anisotropy. Being generally multi-phase and poly-crystalline, where each single crystallite is anisotropic with respect to its physical properties, texture, i.e., the statistical and spatial distribution of crystallographic orientations becomes a constitutive characteristic and determines the material behavior except for grain boundary effects, i.e., in first order approximation. This chapter is in particular an account of modern mathematical texture analysis, explicitly clarifying terms, providing definitions and justifying their application, and emphasizing its major insights. Thus, mathematical texture analysis is brought back to the realm of spherical Radon and Fourier transforms, spherical approximation, spherical probability, i.e., to themathematics of spherical tomography
Handbook of Geomathematics

hal-00564939
https://hal.archives-ouvertes.fr/hal-00564939

Résumé : This study is inserted within the research project Risco, which aims at understanding the causes of oysters mortalities in the bay of Quiberon, since 2006. The objective was to test the feasability of an automatic segmentation of sonar images devoted to the distinction of molluscs (oysters and crepidulas) and sedimentary substrate. The method tested was of the type "segmentation dirigée basée région", implemented on the software SonarScope. It could be applied successfully only on muddy sediment where it succeeded to identify the shellfish sectors with negligeable error. However the distinction between oysters and crepidulas proved to be very delicate. A generalization to other sectors of the bay will be attempted.
Dans le cadre du projet RISCO sur la compréhension des facteurs de mortalité d'huîtres en Baie de Quiberon (France), l'objectif du stage était de tester la possibilité d'une segmentation automatique d'imagerie sonar en vue de distinguer les faciès coquilliers (huîtres et crépidules) du substrat sédimentaire. La méthode testée était de type « segmentation dirigée basée région » implémentée sous le logiciel SonarScope. Cette approche testée uniquement en secteur vaseux s'est montrée capable de détecter sans confusion les secteurs coquilliers. La distinction entre crépidules et huîtres s'est par contre avérée pour le moment très délicate. Une généralisation a d'autres secteurs sédimentaires de la Baie reste à menée.

Droits : 2011 Ifremer, UBS
http://archimer.ifremer.fr/doc/00128/23946/21911.pdf
http://archimer.ifremer.fr/doc/00128/23946/

Éditeur(s) : Université Bordeaux 1
Résumé : Les formations superficielles du plateau insulaire de la Martinique ont été cartographiées à l'aide de données acquises par l'utilisation de techniques complémentaires telles que le sonar à balayage latéral, les photographies sous-marines et les prélèvements à la benne. Ces formations sont constituées par des éléments carbonatés provenant du démantèlement des formations coralliennes actuelles et fossiles et d'éléments volcaniques transportés jusqu'à la mer par voies aérienne et fluviatile. Parmi les structures sédimentaires repérées dans les sables grossiers à très grossiers et dans les graviers, les plus significatives sont des mégarides symétriques, situées entre 20 et 60 m de profondeur. Elles présentent une hauteur comprise entre 0,20 et 0,60 m et une amplitude variant de 1 à 5 m. Le dépouillement des mesures de courantométrie, l'utilisation de statistiques sur les alizés, l'examen de données sur l'état de la mer et la modélisation des courants induits par les vents en période d'alizés et en période cyclonique ont abouti à la définition des caractéristiques des agents hydrodynamiques régnant sur le plateau insulaire de la Martinique. Les caractéristiques des corps sédimentaires permettent d'attribuer aux houles cycloniques plutôt qu'aux courants la responsabilité de leur formation notamment en période cyclonique. Les deux derniers cyclones les plus intenses ayant touché les côtes martiniquaises (David en 1979 et Allen en 1980) ont laissé des empreintes différentes en raison d'une intensité et d'une trajectoire différentes. Les courants de marée, les courants généraux et ceux induits par le vent occupent une place secondaire parmi les agents de remobilisation des sédiments et d'édification des mégarides.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00105/21587/19167.pdf
http://archimer.ifremer.fr/doc/00105/21587/

Résumé : Ifremer launched and coordinated the development of a strategy for the REBENT network (REseau BENThique) in 2000 to monitor the aftermath of the "Erika" oil spill in December 1999. Its aim is to provide consistent baseline knowledge about coastal benthic habitats and constitute a monitoring tool to detect changes at various scales over time and space. Sector-based seabed habitat mapping in shallow water (< 50 m deep), is currently being conducted throughout Brittany's coastal waters through a combination of geoacoustic marine systems and ground-truthing using biological grab sampling and seabed observations. Sedimentological and biological results on Glenan area emphasize a great diversity of subtidal habitats and marine species recognized. Sidescan imagery accentuates the complexity of the communities structure in a marine environment distinguished by strong and regulary roughness of the sea. Maerl biocenose is present at the nord-east of the archipelago. Progressively it gives way to mud sediment colonized by Amphiura filiformis and Haploops in the deeper channel. To the west and the south, substratum types are more coarse, occasionally mobiles, composed of essentially sand community with Nephtys and gravelly sand community with Branchiostoma lanceolatum.
Le Rebent (Réseau benthique), initié en 2000 à la suite de la catastrophe de l'Erika, a pour objectif de suivre les habitats benthiques côtiers et de détecter les changements à différentes échelles de temps et d'espace. L'approche sectorielle dans les petits fonds (< 50 m) des côtes bretonnes combine, des moyens de prospection acoustique, afin de délimiter les principaux types de substrats, avec des prélèvements et des observations biologiques pour caractériser les peuplements macrobenthiques. Les résultats des analyses sédimentologiques et faunistiques montrent autour de l'archipel des Glénan, une grande diversité d'habitats et d'espèces reconnues. L'imagerie acoustique fait ressortir la complexité de leur structuration dans un environnement marin soumis à de fortes et régulières périodes d'agitation. La biocénose de maërl occupe le nord-est de l'archipel. Elle laisse place progressivement aux sédiments envasés à Amphiura filiformis et aux vases à Haploops dans le fond du chenal. A l'ouest et au sud, les subtrats sont plus grossiers, essentiellement sableux à Nephtys et sablo-graveleux à Branchiostoma lanceolatum, épisodiquement mobiles.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/rapport-2301.pdf
http://archimer.ifremer.fr/doc/2006/sup-2301.pdf
http://archimer.ifremer.fr/doc/00000/2301/

Éditeur(s) : Scientific Technical Research Council Turkey-tubitak
Résumé : In 2002, the Bosphorus outlet was mapped using an EM 300 multibeam echo-sounder together with a Chirp sonar system. This survey, carried out on board the Ifremer RV 'Le Suroit' in the frame of the BlaSON project, completes the data previously acquired directly at the mouth of the Bosphorus by Di Iorio et al. (1999) in the frame of a NATO SACLANT Undersea Research project using jointly the NATO RV Alliance, and the Turkish Navy Survey ship 'Cubuklu'. This acoustic imaging has identified a canyon system at the slope and a shallow marine fan, which contains shelf incisions extending the Istanbul Strait incision. Multibeam bathymetry, ultra-high resolution seismic profiling and coring correlations on this subaqueous fan area allowed reconstruction of morphology and patterns of sediment distribution indicative of high energy sediment transport processes. The discovery of a shallow water/shelf type fan directly off shore from the Bosphorus and connected to its outlet is consistent with the theories of sudden discharges of large volumes of water. Age dating obtained at the bottom of this subaqueous shelf fan yielded an age of 6700 yr C-14 BP (uncorrected age) for the first marine mollusc encountered at the base. This is in accordance with a last and abrupt reconnection of the Marmara Sea to the Black Sea. A detailed morphological map of the shelf and slope along with seismic profile interpretation and core correlation is presented here. A synthesis is proposed to explain the formation of this subaqueous fan and its relationship with the last connection between Black and Marmara seas aft er the Last Glacial Maximum. This interpretation can be summarized as follows: stage A corresponds to the first erosion surface seen on the shelf related to the Last Glacial Maximum low stand; stage B is the ravine surface onlapping to ca. -30, -40 m; stage C is a second erosional surface related to a sea level fall and eroding most of underlying Unit 1B; and stage D corresponds to the onset of the fan deposit during a period of high water run-off from the Black Sea entering from the Bosphorus. Avulsion branches show that this fan has been active for a long time.
Turkish Journal Of Earth Sciences (1300-0985) (Scientific Technical Research Council Turkey-tubitak), 2011 , Vol. 20 , N. 3 , P. 287-305

Droits : 2011 TÜBİTAK
http://archimer.ifremer.fr/doc/00036/14676/13677.pdf
http://archimer.ifremer.fr/doc/00036/14676/

Éditeur(s) : Rome : Vitale Mascardi
Résumé : "Les 5 premières parties (vol. 1 et vol. 2) ont une pagination continue. Le traité de Hernandez, à la fin du volume 2, a seul une pagination spéciale. Titre en rouge et noir, avec vignette gravée sur cuivre. Nombreuses figures sur bois dans le texte de plantes, animaux et minéraux. - Reliure veau brun, dos à 6 nerfs, 17e siècle. - Cachet de la bibliothèque de la Ville de Bordeaux. Leclerc, 1154. - Palaü y Dulcet, 113 538. - Pritzel, 4000. - Sabin, 31516"
Siècle(s) traité(s) : 17
Droits : Domaine public
Provenance : Ville de Bordeaux. Bibliothèque municipale
Permalien : http://www.manioc.org/patrimon/BBX17012
BBX17012

Éditeur(s) : The Oceanography Society
Résumé : Submarine hydrocarbon seeps are geologically driven "hotspots" of increased biological activity on the seabed. As part of the HERMES project, several sites of natural hydrocarbon seepage in the European seas were investigated in detail, including mud volcanoes and pockmarks, in study areas extending from the Nordic margin, to the Gulf of Cadiz, to the Mediterranean and Black seas. High-resolution seabed maps and the main properties of key seep sites are presented here. Individual seeps show ecosystem zonation related to the strength of the methane flux and distinct biogeochemical processes in surface sediments. A feature common to many seeps is the formation of authigenic carbonate constructions. These constructions exhibit various morphologies ranging from large pavements and fragmented slabs to chimneys and mushroom-shaped mounds, and they form hard substrates colonized by fixed fauna. Gas hydrate dissociation could contribute to sustain seep chemosynthetic communities over several thousand years following large gas-release events.
Oceanography (1042-8275) (The Oceanography Society), 2009-03 , Vol. 22 , N. 1 , P. 92-109

Droits : 2009 by The Oceanography Society. All rights reserved. Permission is granted to copy this article for use in teaching and research. Republication, systemmatic reproduction, or collective redistirbution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The Oceanography Society. Send all correspondence to: info@tos.org or The Oceanography Society, PO Box 1931, Rockville, MD 20849-1931, USA.
http://archimer.ifremer.fr/doc/2009/publication-6387.pdf
DOI:10.5670/oceanog.2009.11
http://archimer.ifremer.fr/doc/00000/6387/

Éditeur(s) : La Habana : impr. de Spencer y cía
Résumé : Littérature

Droits : Domaine public
Provenance : Institut des Hautes Études de l'Amérique latine, Bibliothèque Pierre-Monbeig
Permalien : http://www.manioc.org/patrimon/IHE14003
IHE14003

Éditeur(s) : San Juan : Editorial Santurce printing works

Droits : Domaine public
Provenance : Institut des Hautes Études de l'Amérique latine, Bibliothèque Pierre-Monbeig
Permalien : http://www.manioc.org/patrimon/IHE14027
IHE14027

Éditeur(s) : Springer
Résumé : Based on new multibeam bathymetric data, seismic-reflection profiles and side-scan sonar images, a great number of submarine failures of various types and sizes was identified along the northern margin of the Ligurian Basin and characterized with 3 distinct end-members concerning their location on the margin, sedimentary processes and possible triggering mechanisms. They include superficial landslides mainly located in the vicinity of the main mountain-supplied rivers and on the inner walls of canyons (typically smaller that 10(8) m(3) in volume: Type 1), deep scars 100-500 m high along the base of the continental slope (Type 2), and large-scale scars and Mass Transport Deposits (MTDs) affecting the upper part of the slope (Type 3 failures). The MTDs are located in different environmental contexts of the margin, including the deep Var Sedimentary Ridge (VSR) and the upper part of the continental slope in the Gulf of Genova (Finale Slide and Portofino Slide), with volumes of missing sediment reaching up to 1.5 x 10(9) m(3). High sedimentation rates related to hyperpycnal flows, faults and earthquake activity, together with sea-level fluctuations are the main factors invoked to explain the distribution and sizes of these different failure types.
Marine Geophysical Research (0025-3235) (Springer), 2011-03 , Vol. 32 , N. 1-2 , P. 225-243

Droits : Springer Science+Business Media B.V. 2011
http://archimer.ifremer.fr/doc/00043/15387/14028.pdf
DOI:10.1007/s11001-011-9123-3
http://archimer.ifremer.fr/doc/00043/15387/

Éditeur(s) : Paris : Treuttel et Wurtz
Extrait de : Collection des voyages et des découvertes des espagnols depuis la fin du XVème siècle
Siècle(s) traité(s) : 15
Droits : Domaine public
Provenance : Archives départementales de Guadeloupe
Permalien : http://www.manioc.org/patrimon/ADG17081
ADG17081

Résumé : The use of acoustical systems in various human activities in the ocean (industry, defence, science) raises the issue of their impact upon marine mammals populations. Several serious accidents linked to the use of naval sonars led the military, industrial and scientific communities to investigate the potential dangers of their own activity. This report aims at identifying the risks for the cetaceans linked to the use of acoustic and seismic systems currently used for oceanographic science. The analysis proposed here stays within the frame of bibliography synthesis and elementary modelling, and brings no new scientific elements on the topic. An overview of the status of cetacean populations is given first, with a summary of the possible acoustical threats. Risks are classified and described, insisting on the cases of massive stranding events. The present status of knowledge about auditory characteristics of cetaceans is summarised, and the definition of an objective threshold for acoustical risk is discussed ; the usually-admitted values are finally retained, despite of their evident limitations. The report presents also the emission characteristics of the various acoustic and seismic systems used in oceanographic, emphasising the ones operated by Ifremer; for the potentially harmful ones (according to the currently-used criteria) a model is proposed for the radiated acoustical intensity field, giving the extent of risk areas. This analysis concludes to the harmlessness of most systems, excepted heavy seismics and at a lesser degree low-frequency multibeam echosounders. Finally a variety of possible mitigation measures are presented and discussed; the regulations imposed by some countries are detailed. The report finally recommends both short-term measures aimed at limiting the potential risks, and longer-term actions for participating in the general effort of scientific and technological research in this field.
L'emploi des systèmes acoustiques dans les diverses activités humaines en milieu océanique (industrielles, de défense, scientifiques) pose le problème de leur impact sur les populations de mammifères marins. L'évidence de plusieurs événements graves liés à l'utilisation de sonars navals a amené les communautés militaires, industrielles et scientifiques à s'interroger sur les dangers potentiels de leurs propres activités. Le présent rapport tente de cerner les risques, pour les Cétacés, liés à l'emploi des systèmes acoustiques et sismiques couramment mis en oeuvre pour la recherche océanographique. L'analyse proposée ici reste à un niveau de synthèse bibliographique et de modélisation élémentaire, et n'offre pas d'éléments scientifiques nouveaux sur la question. On commence par donner un panorama de la situation des populations de cétacés et des agressions sonores qui les menacent. Les risques acoustiques sont répertoriés et décrits, en insistant sur les cas avérés d'échouages massifs. L'état actuel de connaissances sur les caractéristiques auditives des cétacés est résumé, et la définition d'un seuil objectif de risque acoustique est discutée ; on retient par défaut les valeurs de seuils généralement admises actuellement, en dépit de leurs limitations évidentes.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/rapport-2390.pdf
http://archimer.ifremer.fr/doc/00000/2390/

Éditeur(s) : La Habana : Secretaría de Educación. Dirección de Cultura
Extrait de : Cuadernos de cultura pointvirgule Sexta serie, 3
Siècle(s) traité(s) : 20
Provenance : Université Caen Normandie. Service commun de la documentation
Permalien : http://www.manioc.org/patrimon/CAE19022
CAE19022