Éditeur(s) : Soc Francaise D Ichtyologie
Résumé : This work deals with the fishing effects on the diversity dynamics of demersal fish communities, focusing on the biotic interactions. Multispecies indices were used in order to characterise the demersal fish community dynamics of the Bay of Biscay and of the Gulf of Lions. These are the diversity indices, the temporal variability of the total biomass and of the slope of the number size spectra and the slope of the species-area curves (spatial segregation). The data were provided by yearly bottom trawl surveys EVHOE, CHALIST and MEDITS carried out in these two areas since 1983 by IFREMER for stock assessment. The differences between areas are related to a fishing index (mean value of the annual landings of demersal fish per surface area). Other areas are included in the analysis when the index values are available from the published literature (North Sea, Scotian Shelf, Kenya, French Guyana). From the diversity indices analysis it is argued that the Gulf of Lions community is more diverse and less disturbed than the Bay of Biscay one. This result is not consistent with a fishing effect. It is interpreted as a biogeography pattern. The total biomass variability and the slope variability of size spectra are higher in the most harvested areas than in the least ones. On the contrary, the species-area slope is the lowest in the most harvested areas. Theoretically, biotic interactions decrease the total biomass variability and the spectra slope variability because of compensations, and increase the species area slope because of competitive exclusion. It is concluded that harvesting alters biotic interactions and favours local coexistence by decreasing competitive exclusion. The species diversity maintenance depends on competitive exclusion. Hence, biodiversity is threatened not only by a direct fishing effect but also by a dynamics alteration.
Ce mémoire aborde le problème de l'impact de l'exploitation par la pêche sur la dynamique de diversité des peuplements de poissons démersaux. Les effets de la pêche sur le rôle des interactions biotiques entre espèces dans la dynamique des peuplements sont plus particulièrement analysés à l'aide de descripteurs multispécifiques. Les descripteurs utilisés sont les indices de diversité, la variabilité temporelle de la biomasse totale et de la pente multispécifique du spectre de poids et la pente des droites d'accumulation d'espèces mesurant la ségrégation spatiale. Les valeurs de ces indices sont calculées à partir des données de campagnes annuelles de chalutage de fond EVHOE, CHALIST et MEDITS, menées par l'IFREMER depuis 1983 pour évaluer les ressources halieutiques dans le golfe de Gascogne et dans le golfe du Lion. Les différences de caractéristiques de dynamique entre les deux peuplements révélées par ces descripteurs sont mises en relation avec un indice d'exploitation (valeur moyenne des débarquements annuels, divisée par la surface du plateau de la région concernée). D'autres régions ont été intégrées dans cette analyse lorsque les valeurs des indicateurs étaient disponibles dans la littérature (Mer du Nord, plateau de Nouvelle-Ecosse, Kenya et Guyane Française). Les indices de diversité utilisés permettent de mettre en évidence que le peuplement du golfe du Lion est plus diversifié et moins soumis à perturbations que celui du golfe de Gascogne. Ces caractéristiques semblent dues à l'histoire biogéographique de ces deux régions et non à un effet de la pêche. La variabilité de la biomasse totale et celle de la pente du spectre multispécifique augmentent depuis les régions les moins exploitées vers les plus exploitées. A l'inverse, la ségrégation spatiale diminue. En théorie, les interactions entre espèces diminuent la variabilité temporelle de la biomasse totale et de la pente du spectre multispécifique, à cause de compensations entre espèces, et augmentent la ségrégation spatiale par exclusion compétitive. L'interprétation donnée des résultats obtenus est ainsi une altération des interactions entre les espèces par l'exploitation. En prélevant de la biomasse, l'exploitation augmente la disponibilité des ressources pour les individus non pêchés. En conséquence, l'exclusion compétitive diminue et la coexistence locale des individus est facilitée. A long terme, la diversité est donc menacée, non seulement par raréfaction des espèces prélevées par l'exploitation mais aussi parce que les interactions sont altérées et que le maintien de la diversité en dépend pour partie.
Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2001 , Vol. 25 , N. 3 , P. 293-294

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00000/10248/7688.pdf
http://archimer.ifremer.fr/doc/00000/10248/

Éditeur(s) : HAL CCSD
Résumé : International audience
The most active deep convection area in the western Mediterranean Sea is located in the Gulf of Lions. Recent studies in this area provides some insights on the complexity of the physical dynamics of convective regions, but very little is known about their impacts on the biogeochemical properties. The CASCADE (CAscading, Surge, Convection, Advection and Downwelling Events) cruise, planed in winter 2011, give us the opportunity to compare vertical profiles of properties sampled either during stratified conditions or after/during a convection event. In the present study, we focus on the distributions of the carbonate system properties (mainly total alkalinity, AT; and total dissolved inorganic carbon, CT) because, in the context of the climate change, deep convection areas are suspected to significantly increase the sequestration of anthropogenic CO2 (CANT). Given its limited size, the impact of the Mediterranean Sea on the global carbon budget is probably minor but this marginal sea can be used as a laboratory to better understand carbon sequestration and its transfer to the basin interior by deep convection processes. Distributions of AT and CT, both measured from bottle samples, and that of CANT (estimated with the TrOCA approach) are first analyzed in the light of other key properties (salinity, temperature, and dissolved oxygen). An objective interpolation procedure is then applied to estimate CT and AT from CTD measured properties. With this procedure, the vertical resolution goes from a maximum of 32 samples per station to one property estimate every meter (more detailed distributions are obtained). Results provide arguments to conclude that CANT is rapidly transferred to the deepest layer due to deep convection events. During deep convection events, the increase of CANT in the water column is positively correlated to that of potential density and oxygen content. The challenge of quantifying the amount of sequestered carbon is however not resolved due to the complexity and the highly dynamical nature of the convective regions. Deep convection in the Gulf of Lions, in parallel with cascading along the continental slope, could thus potentially explain the very high levels of both CANT and acidification estimated in the deep layers of the western Mediterranean Sea.
Deep Sea Research Part I: Oceanographic Research Papers

hal-01336725
https://hal-univ-perp.archives-ouvertes.fr/hal-01336725
DOI : 10.1016/j.dsr.2016.04.003

Éditeur(s) : Inter-Research
Résumé : The spatial structure of demersal fish assemblages on the continental shelf of the NW Mediterranean Sea was examined on a large scale between the Straits of Gibraltar and the Gulf of Lions. In contrast to its predominant role in the spatial distribution of species composition, described worldwide, it seems depth has only a limited effect on the distribution patterns of the total abundance and diversity of demersal fishes. In addition, evidence is provided for the division of the whole study area into 3 geographical fish assemblages. The influence of Atlantic inputs and the semi-permanent Almena-Oran hydrographic front play a key role in defining the Alboran Sea as a specific fish fauna area. Moreover, the clear differentiation between 2 distinct assemblages in the Gulf of Lions and the Catalan Sea could be partly linked to the North Balearic front. These results contribute to the current debate on the definition of spatial units for the purpose of demersal fisheries management. They also stress the complexity of developing an ecosystem approach which deals simultaneously with species composition and biodiversity aspects of ecosystems management.
Marine Ecology Progress Series (0171-8630) (Inter-Research), 2005-08 , Vol. 297 , P. 245-257

Droits : Inter-Research 2005
http://archimer.ifremer.fr/doc/2005/publication-3623.pdf
DOI:10.3354/meps297245
http://archimer.ifremer.fr/doc/00000/3623/

Éditeur(s) : Soc Francaise D Ichtyologie
Résumé : The energy value of the main prey and the growth of juvenile hake in the Gulf of Lions were analysed to determine whether fish condition could be linked to difference in prey quality and resulted in growth difference. Large differences in energy content (15.6 to 23.6 kJ g(-1) DW) among prey types were recorded with low values found in amphipods and natantid shrimps, intermediate values in euphausiids and mysids, and high values in fish. High condition in juvenile hake was linked to the consumption of prey with high energy content. However, no difference in fish growth was observed by the analysis of otolith micro-increments.
Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2012-06 , Vol. 36 , N. 2 , P. 323-328

Droits : 2012 Société Française d’Ichtyologie
http://archimer.ifremer.fr/doc/00092/20332/18611.pdf
http://archimer.ifremer.fr/doc/00092/20332/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300-6100, 5650-5400, 4400-4050, 3650-3200, 2800-2600, 1950-1400 and 400-50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150-650 cal yr BP) was characterised by low storm activity.;The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling-in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain. (C) 2011 University of Washington. Published by Elsevier Inc. All rights reserved.
ISSN: 0033-5894

hal-00760909
https://hal.archives-ouvertes.fr/hal-00760909
DOI : 10.1016/j.yqres.2011.09.002

Éditeur(s) : HAL CCSD
Résumé : International audience
In the analysis of coastal hazards, the features of extreme waves are determining information to question the impact of storms to the coast. The spatial behaviour of extreme waves is even more valuable especially since it is sparsely provided. Regarding recent applications in other contexts, a kind of statistical models called max-stable processes is relevant for modelling spatial extreme events. Max-stable processes are extensions of the well-known Generalised Extreme Value (GEV) distribution. Unlike univariate approaches, max-stable processes consider spatial dependence of a phenomenon. Such a modelling also overtakes a standard multivariate approach by providing information continuously over the area studied, even where no observation is available. Relying on such a stochastic modelling, the aim of this study is to discuss the extreme waves hazards in the Gulf of Lions, focusing on their spatial behaviour.
34th Conference on Coastal Engineering
Seoul, South Korea

lirmm-01382568
https://hal-lirmm.ccsd.cnrs.fr/lirmm-01382568
https://hal-lirmm.ccsd.cnrs.fr/lirmm-01382568/document
https://hal-lirmm.ccsd.cnrs.fr/lirmm-01382568/file/7553-31212-1-PB.pdf
DOI : 10.9753/icce.v34.management.17

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : Les lagunes du Golfe du Lion constituent un patrimoine naturel reconnu ainsi qu'un enjeu essentiel pour les activités économiques locales. Leur évolution morphologique est donc une question importante dans le contexte actuel de changements climatiques et environnementaux. L'analyse de données topo-bathymétriques du système des étangs Palavasiens a permis de mieux cerner son évolution depuis le XVIIIème siècle. Les actions anthropiques et les apports du bassin versant apparaissent comme les facteurs principaux de l'évolution du système. Au cours des 40 dernières années, le système montre une tendance à se combler lentement avec une accumulation moyenne de 1,3 mm/an. Des différences de fonctionnement sur chacun des étangs sont mises en lumière en fonction des forçages naturels et anthropiques locaux. Lagoons of the Gulf of Lion, recognized for their natural heritage, are a key challenge for local economic activities. Their morphological evolution is an important issue in the current context of climate and environmental changes. Analysis of topo-bathymetric data of the Palavasian lakes system has helped to clarify its evolution since the XVIII th century. Human impacts and contributions from the watershed appear to be the main drivers governing the evolutionof the system. Over the past40 years, the system shows a tendency to slowly fill at an accumulation rate of 1.3 mm/year. Differences between lagoons are highlighted according to local natural and anthropogenic forcings.
ISSN: 1760-8716

hal-00854075
https://hal.archives-ouvertes.fr/hal-00854075
DOI : 10.5150/revue-paralia.2011.007

Éditeur(s) : HAL CCSD Institute of Oceanography and Fisheries, Split
Résumé : International audience
This study deals with temporal variations in eel Anguilla anguilla diet, sampled seasonally in the Languedocian Mauguio lagoon (Gulf of Lion), from Autumn 1998 to Summer 1999. Eel mainly feeds on benthic organisms, primarily small Amphipoda, Crustacea (mainly Gammarus gr. locusta), Polychaeta, insect larvae (Chironomidae) and small fish. Based on variations in the eels feeding regime, seasonal influence is illustrated by decreased feeding activity in summer, which progressively increases during the following seasons. The trophic quality available to eels in the Mauguio lagoon depends more on allochtonous inputs from the catchment area than on its own hydrodynamics on which water of marine origin has little influence due to its long distance from the sea. Variations observed during the four seasons illustrate the opportunist type feeding behaviour of eels. They consume the most available benthic preys at a given moment without using a particular feeding strategy like specialisation or generalisation. Eel adapts its diet according to the available resources offered by the ecosystem. Because of this eel, as an amphihaline migrant species, can be characterised as an obvious indirect bioindicator of the trophic capacity and very marked level of confinement in the brackish lagoon ecosystem of Mauguio.
ISSN: 0001-5113

hal-00750416
https://hal.univ-antilles.fr/hal-00750416
https://hal.univ-antilles.fr/hal-00750416/document
https://hal.univ-antilles.fr/hal-00750416/file/Acta_Adriatica_2009_50_2_.pdf

Éditeur(s) : HAL CCSD
Résumé : The effects of climate change on extreme events are difficult to assess because extremes present large variability and consequently, it is difficult to identify significant trends in relation to the lack of instrumental long time series. Here we present a record of these extreme storm events in the French Mediterrannean coast over the past 7000 years based on a long sediment core from lagoonal environment in Gulf of Lions. Using a high resolution multiproxies approach on core associating grain size, faunal to reconstruct Mid to Late Holocene history of backbarrier deposits in relation to landfalling activity. Even if change in lagoon geomorphological setting over the Holocene does not allow to compare storm events in terms of intensity trough time, we have recorded six periods of increase in storm activity at 6200, 5500, 4400, 3200, 1500 yr cal B.P. and over the LIA (450 and 100 yr cal B.P.). These evidences of changes in coastal hydrodynamic, inversely correlated to periods of aridification in Western Mediterranean region, are in phase with those observed over the North Atlantic and correspond to Holocene cooling events. This increase in storm activity during Holocene cold events over Mediterranean region was probably due to thermal gradient increase leading to enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain. This study demonstrates that temperatures in North Atlantic region influence the severe storm activity and therefore the Mediterranean climate at Holocene timescale.
Les effets du changement climatique sur les événements extrêmes sont difficiles à estimer car ces phénomènes présentent une large variabilité, et par conséquent il est délicat d'identifier des tendances significatives compte tenu de l'absence de longues séries de données instrumentales. Dans cette étude, nous présentons un enregistrement de ces tempêtes extrêmes sur la côte Méditerranéenne française au cours des 7000 dernières années à partir de carottes sédimentaires prélevées dans un système lagunaire du Golfe du Lion. L'utilisation d'une approche multi-traceur à haute résolution avec des analyses granulométriques, faunistiques, géochimiques (XRF), en minéraux argileux associées à des données chronologiques de radiocarbone et de 210Pb, 137Cs ; nous a permis de reconstruire l'histoire, au cours de l'Holocène, des dépôts lagunaires en relation avec l'activité des tempêtes. Bien que les paramètres morphologiques de cet environnement lagunaire aient changé durant l'Holocène, ne permettant pas de comparer ces événements au cours du temps en terme d'intensité, nous enregistrons six périodes d'augmentation de l'activité des tempêtes datées à 6200, 5500, 4400, 3200, 1500 an cal B.P. et durant le Petit Age Glaciaire (de 450 à 100 an cal B.P.). Ces changements de l'activité hydrodynamique côtière, en antiphase avec les périodes d'aridifications en Méditerranée de l'Ouest, sont corrélées avec celles observées dans le bassin Nord Atlantique et correspondent aux événements de refroidissement Holocène. L'augmentation de l'activité des tempêtes dans la cette région de la Méditerranée durant les périodes froides, associée à une diminution des températures au pôle Nord, est probablement liée à l'augmentation du gradient thermique qui, par interaction barocline, favorise les cycles d'évolution des tempêtes dans toute l'Europe et la Méditerranée de l'Ouest. Cette étude démontre ainsi que la température dans la région Nord Atlantique influence l'activité des tempêtes extrêmes et donc du climat Méditerranéen à l'échelle de l'Holocène.
https://tel.archives-ouvertes.fr/tel-00437757

tel-00437757
https://tel.archives-ouvertes.fr/tel-00437757
https://tel.archives-ouvertes.fr/tel-00437757/document
https://tel.archives-ouvertes.fr/tel-00437757/file/Sabatier_these.pdf

Éditeur(s) : Elsevier
Résumé : The composition of the glacial vegetation of southern French plains has been a matter of debate for several decades. Vegetation is considered as steppic according to French and Spanish lacustrine pollen records whereas cave deposits suggest the presence of mesothermophilous trees through the Last Glacial Maximum. In our paper, we display new palynological records from marine sediments of the Gulf of Lions. They indicate the presence of Abies, Picea and deciduous Quercus in the Gulf of Lions, certainly located in the drainage basins of the Pyreneo-Languedocian rivers. These populations that were sensitive to short climatic events during Marine Isotopic Stage 2 could have been linked to northeastern Spanish and southeastern French relicts already evidenced by phylogenetic data. These trees were absent from the Rhone drainage basin during the deglaciation and certainly also disappeared from the Pyreneo-Languedocian drainage basins from ca 17 to 15 ky cal BP. Finally, the Last Glacial Maximum does not appear as stable, cold and dry as previously thought.
Quaternary Science Reviews (0277-3791) (Elsevier), 2007-04 , Vol. 26 , N. 7-8 , P. 1037-1054

Droits : 2007 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2007/publication-2804.pdf
DOI:10.1016/j.quascirev.2006.12.009
http://archimer.ifremer.fr/doc/00000/2804/

Éditeur(s) : HAL CCSD
Résumé : Livret-guide
L'objectif de l'excursion en Languedoc est d'observer les structures géologiquesdu rifting OligoMiocène du Golfe du Lion et d'analyser les évidences tectoniques, sédimentologiques, volcaniques et morphologiques de l'évolution complexe qui a suivi. Le premier jour, nous observerons les relations tectonique sédimentation dans les bassins en extension synrift et post‐rift. Le deuxième jour nous conduira dans l'arrière pays dont le paysage a été façonné par des surrections et des phases d'incisions. Est‐ce l'épaulement du rift ? La troisième journée sera consacrée aux évènements Miocène supérieur à actuel, notamment les évidences de terrain de l'assèchement de la Méditerranée au Messinien et le volcanisme alcalin Quaternaire. Nous terminerons le dernier jour par l'analyse des processus de formation et d'évolution du littoral sableux. L'occasion de se rafraîchir dans la Grande Bleue juste avant de reprendre le chemin du retour pour se préparer pour la rentrée scolaire.
https://hal.archives-ouvertes.fr/hal-00856255

hal-00856255
https://hal.archives-ouvertes.fr/hal-00856255
https://hal.archives-ouvertes.fr/hal-00856255/document
https://hal.archives-ouvertes.fr/hal-00856255/file/livret-guideExcuLanguedocUPA.pdf

Éditeur(s) : HAL CCSD Station Biologique
Résumé : International audience
This study deals with temporal variations in eel diet Anguilla anguilla sampled at each of the four seasons in the Languedocian Prévost lagoon (Gulf of Lion) from Autumn 1998 to Summer 1999. The following feeding indices were calculated based on observations of 12 categories of prey found in the contents of full stomachs: coefficient of vacuity CV, degree of fullness DR, occurrence frequency PP, relative abundance N (in %) and relative weight P (in %). The interpretation of results is also based on the Costello's method (1990) which combines PP and N. Anguilla anguilla mainly feeds on benthic organisms, primarily Gammarus gr. locusta, Polychaeta, insect larvae, small fish. Based on variations in eel diet, seasonal influence is illustrated by a decrease in feeding activity in summer which gradually increases during the following seasons. The good trophic quality available to eels in the Prévost lagoon depends on its hydrodynamics which is directly related to the movement of water entering and leaving lagoon by a short communication with the sea. This water movement accelerates the enrichment and production processes of this ecosystem. Changes observed during the four seasons illustrate an opportunistic type of feeding behaviour. Eels consume the most available benthic prey. They favour the importance of the prey at a given moment without using a particular feeding strategy like specialisation or generalisation. Thus, eel adapts its diet in adjusting available energy resources in the ecosystem. Because of this, the lagoon-resident species Anguilla anguilla is an obvious indirect bioindicator of the trophic capacity and present level of confinement in the brackish water lagoon ecosystem of Prévost.
ISSN: 0007-9723

hal-00753021
https://hal.univ-antilles.fr/hal-00753021

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : The south part nearshore zone of the Gulf of Lions coast (Mediterranean Sea) is characterized by a double crescentic sandbar system. During the winter 2007, a campaign of intensive hydrodynamical measurements (current profiles) was realized. During this campaign, based mainly on ADCPs, the maximal recorded wave height was 1.5 m. Four events were observed; two of those had northern incidence, one with southern incidence and a last one with frontal incidence. This paper proposes 3D hydrodynamical circulation maps over this microtidal bar system. The currents described reveals rip, bed-return and longshore currents strongly influenced by the wind-waves forcing and the bathymetry. At the apex of the oblique incidence events, the longshore component is the most important. The breaker zone is only located over the inner bar. During storm waning conditions, the cross-shore currents appear over the trough of the outer bar. The hydrodynamic circulation is then compared with other observations made in the literature.
ISSN: 0749-0208
Szczecin, Poland

hal-00767593
https://hal.archives-ouvertes.fr/hal-00767593

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Consumption of marine organisms represents one of the main exposure sources of contaminants for human populations. To obtain a global view of the contamination in commercial fish in the NW Mediterranean Sea, we analysed four types of priority contaminants (PCBs, PBDEs, Hg and Cs-137) in the European hake, Merluccius merluccius, from the Gulf of Lions in relation with organism's trophic level (delta N-15). All contaminants presented a significant increase in concentration in hake muscle with trophic level. However, obvious differences between contaminants were evidenced. Biomagnification factors (BMF and FWMF) along the hake food web were higher for Hg and CB-153 than for BDE-47 and Cs-137, and increase in contaminant concentration with trophic level occurred at different rates depending on contaminants. Such differences of biomagnification patterns can be related to physico-chemical properties of the different contaminants. (C) 2012 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2012-05 , Vol. 64 , N. 5 , P. 974-983

Droits : 2012 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00085/19583/17484.pdf
DOI:10.1016/j.marpolbul.2012.02.014
http://archimer.ifremer.fr/doc/00085/19583/

Éditeur(s) : Elsevier Sci Ltd
Résumé : A detailed morphological analysis of the outer shelf and continental slope of the Western Gulf of Lion is presented, based on swath bathymetry data together with sub-bottom profiles and high resolution seismic reflection profiles. These data reveal two main erosive features, of very different dimensions: the axial incision and the canyon's major valley. The height of axial incisions' flanks with respect to the canyon deepest point (the thalweg) ranges from 40 to 150 m. It creates a small axial erosive path within the canyon's major valley, which is typically bounded by flanks of more than 700 m in height. We interpret the axial incision observed in the sea floor as the imprint of turbidity currents that eroded the floor of canyons during phases of connection to rivers (hyperpycnal turbidity current). Such currents are most likely to have formed during the Last Glacial Maximum (LGM) as both proximity of the shoreline (due to the lowstand of sea level) and high detrital sediment supply (due to glacial abrasion upstream) increased the flow of sediments delivered to the canyon heads. Fossil axial incisions, observed in seismic lines, are related to equivalent conditions. The axial incision, however, has a key influence on canyon evolution as it triggers mass wasting of different sizes that affect the canyon's major valley (head and flanks). We interpret the geometry of the canyon's major valley as the result of recurrent activity of axial incisions. These periods of activity occurred during low sea levels at glacial maxima and show a cyclicity of 100,000 years for the last 400,000 years.
Marine And Petroleum Geology (0264-8172) (Elsevier Sci Ltd), 2005-06 , Vol. 22 , N. 6-7 , P. 805-826

Droits : 2005 Elsevier Ltd All rights reserved
http://archimer.ifremer.fr/doc/2005/publication-353.pdf
DOI:10.1016/j.marpetgeo.2005.03.011
http://archimer.ifremer.fr/doc/00000/353/

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : We tested the applicability of the BIT (branched and isoprenoid tetraether) index as a proxy for palaeoflood events in the river-dominated continental margin of the Gulf of Lions (NW Mediterranean). We compared the concentrations of branched glycerol dialkyl glycerol tetraethers (br GDGTs) and crenarchaeol in suspended particulate matter (SPM) collected downstream in the Rhône River, as well as in surface sediments and a ca. 8m piston core from the Rhône prodelta. The core covered the last 400 yr, with four distinct intervals recording the river influence under natural and man-induced shifts in four main channels of the river mouth (Bras de Fer, Grand Rhône, Pégoulier,and Roustan). The results indicate that there are mixed sources of br GDGTs and crenarchaeol in the prodelta, complicating applicationof the BIT index as an indicator of continental organic carbon input and thus as a palaeoflood proxy. However, the sedimentary BIT record for the period when continental material was delivered by the river more directly to the core site (Roustan phase;1892 to present) mimics the historical palaeoflood record. This shows the potential of the BIT index as a palaeoflood proxy, provided that the delivery route of the continental material by rivers to the core sites remains constant over time. The study also highlights the idea that shifts in river channels should be taken into account for the use of the BIT index as a palaeoflood proxy.
Organic Geochemistry (0146-6380) (Pergamon-elsevier Science Ltd), 2014-10 , Vol. 75 , P. 99-108

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00198/30969/29345.pdf
DOI:10.1016/j.orggeochem.2014.06.011
http://archimer.ifremer.fr/doc/00198/30969/

Éditeur(s) : IEEE
Résumé : Bathymetric estimation using remote sensing images has previously been applied to high spatial resolution imagery such as CASI, Ikonos, or SPOT but not on medium spatial resolution images (i.e., MERIS). This choice can be justified when there is a need to map the bathymetry on large areas. In this letter, we present the results of the bathymetry estimation over a large known area, the Gulf of Lion (France), expanding over 270 x 180 km.
Geoscience and Remote Sensing Letters, IEEE (1545-598X) (IEEE), 2007-04 , Vol. 4 , N. 2 , P. 274-277

Droits : 2007 IEEE
http://archimer.ifremer.fr/doc/2007/publication-2597.pdf
DOI:10.1109/LGRS.2007.890548
http://archimer.ifremer.fr/doc/00000/2597/

Éditeur(s) : Elsevier Science Bv
Résumé : The main objective of this work was to establish the influence of sex, maturity and reproduction on the contamination of the demersal fish Merluccius merluccius by organochlorine compounds. Polychlorinated biphenyls (PCBs) and p,p'DDE were quantified in muscle, liver and gonads of female and male hakes collected in the Gulf of Lions in 2004 and 2005. Observed levels appeared higher than the population of the Bay of Biscay and lower than the population of the Thyrrenian Sea. Contaminant fingerprints were roughly constant whatever the studied organ and the hake biological condition. Concentrations varied significantly according to the sex and maturity of hakes. Mature specimens were more contaminated than immature, and males presented higher levels than females. This sex effect can be linked to a lower growth rate of males, and a contaminant elimination during female spawning. Gonadal contamination depends on the importance of lipid content and increases with the maturation degree. Although the main organ of energy and PCB storage is the liver, muscle appears as the main contributor to the gonad contamination. (C) 2009 Elsevier B.V. All rights reserved.
Science Of The Total Environment (0048-9697) (Elsevier Science Bv), 2009-12 , Vol. 408 , N. 2 , P. 304-311

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00000/11129/9317.pdf
DOI:10.1016/j.scitotenv.2009.10.004
http://archimer.ifremer.fr/doc/00000/11129/

Éditeur(s) : Elsevier
Résumé : Emplacement of post-glacial turbidites is commonly controlled by rapid changes in sea level or by seismicity. On the continental rise of the Gulf of Lions (Western Mediterranean), an aseismic area, we identified turbiditic beds deposited during the rising stage and highstand of sea level. Swath bathymetry, sediment cores, in situ Cone Penetrating Tests (CPTU), heavy mineral associations and radiocarbon dating determined the source, composition, distribution and age of the turbiditic beds. Turbidites are composed of homogeneous to positively graded silts to medium sand with quartz (up to 90%), shell debris and shelfal benthic faunas. Their distribution on the sea floor is very patchy and controlled by abundant inherited erosional bedforms. Their source is found in relict regressive sands at the outershelf. Their deposition occurred just after the onset of the post-glacial sea level rise and the concomitant sediment starvation of the Rhone deep sea turbiditic system until recently. Whilst canyons are fed with sand by strong seasonal hydro-sedimentary dynamics on the outershelf, the emplacement of post-glacial turbidites is not controlled by sea level changes but probably by the periodic flushing of the canyons. Our study revealed that this low energy aseismic margin undergoes significant transport of sand, down to the base of slope, during the sea-level rise and the Holocene highstand.
Marine Geology (0025-3227) (Elsevier), 2009-02 , Vol. 257 , N. 1-4 , P. 65-86

Droits : 2009 Published by Elsevier Ltd.
http://archimer.ifremer.fr/doc/2009/publication-6316.pdf
DOI:10.1016/j.margeo.2008.10.013
http://archimer.ifremer.fr/doc/00000/6316/

Éditeur(s) : Springer
Résumé : The Balearic Basin is a young basin composed of thick Plio-Quaternary sediments, including active gravity sedimentation. During the Quaternary, gravity processes deposited (1) turbidite systems, either as symmetrical fans (Petit-Rhone and Valencia fans) or asymmetrical ridges (Marseille-Planier, Grand- Rhone and Pyreneo-Languedocian ridges) and (2) several mass-transport deposits, indicating recurrent sedimentary failures of the margin. This paper synthesizes previous works and proposes a chronological sedimentary evolution for the basin. Except for the last 20 ka, the chronostratigraphy remains poorly constrained but should soon be established for the last 500 ka, based on the PROMESS1 drillings on the outer shelf of the Gulf of Lions, and hopefully for the last 30 Ma, based on ultra-deep drilling in the deep basin from aboard the Chikyu research vessel (IODP proposal Pre699).
Geo-Marine Letters (0276-0460) (Springer), 2006-12 , Vol. 26 , N. 6 , P. 347-359

Droits : 2006 Springer Science+Business Media
http://archimer.ifremer.fr/doc/2006/publication-2171.pdf
DOI:10.1007/s00367-006-0044-0
http://archimer.ifremer.fr/doc/00000/2171/