Résumé : The slides were taken on collecting trips sponsored by the William L. Bryant Foundation, where books, music and art indigenous to the regions were gathered. They are organized by geographical location.
View of shoreline, plants, and resorts near Bathsheba Beach. Slide labeled Barb 26
Barbados -- Caribbean region -- Bathsheba, Saint Andrew

Droits : All rights to images are held by the respective holding institution. This image is posted publicly for non-profit educational uses, excluding printed publication. For permission to reproduce images and/or for copyright information contact Special Collections & University Archives, University of Central Florida Libraries, Orlando, FL 32816 phone (407) 823-2576, email: speccoll@ucf.edu
CFM1972_01a
Sheet 20: 19
http://ufdc.ufl.edu/AA00017934/00001

Éditeur(s) : HAL CCSD
Résumé : International audience
Island barriers are common features along the world coastlines. They have a crucial role in protecting inland and rich lagoonal ecosystems. Erosion and sand transfers on these island barriers during extreme events such as tropical storms or typhoons remain poorly investigated. This work focuses on a multi-scales nalysis (season to decade) of the morphodynamics of Wan-Tzu-Liao sand barrier subjected to extreme waves and sea surges. We combine topographic measurements of the emerged beach at seasonal scale between 2011 to 2012 and long-term (1993-2009) shoreline changes using aerial photographs and satellite images. At the seasonal scale, during Monsoon, the sand was taken from the beach-front and transported seaward outside the study area. During typhoons season, 12 typhoons drove a beach recovery process resulting in a seaward shoreline shift. This annual behavior is discussed in term of roll-over process of the barrier. At the decadal scale, the shoreline changes evidence cross-shore processes in the north part of the barrier and longshore processes in the south. Although the chronic landward migration displays several stages, the strong losses of the barrier area occurs only since 2004 and call into question the general concept of conservation of mass during the roll-over of a barrier.
Revue Paralia, XIIIème Journées Nationales Génie CIvil Génie Côtier
Dunkerque, France

hal-01018203
https://hal.archives-ouvertes.fr/hal-01018203

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : The wave-dominated beach barrier of Villeneuve-Lès-Maguelone extends between Palavas and Frontignan (Gul f of Lions, northernmost Me diterranean Sea), along a slightly natural sandy protected area char acterized by typical and well-expressed morphologies. In the nearshore, the sea bottom shows one or two approximately rectilinear sand bars. In 2010-2011, we pe rformed a 6 month-long monitoring (autumn 2010/late spring 2011) of a 500 meter-long se gment along this sand barrier. We used RTK D-GPS offering centimeter resolution to acquire sets of elevation data on the beach and the upper shoreface. The study is innovative because a full morphologic monitoring was performed each time the wave/ wind conditions changed significantly. These changes were tracked in real-time thanks to a set of hydrodynamic equipments deployed at sea, including well-known DREAL buoys. We identify from well- documented data: (1) a beach reconstruction cycle at the shorelin e after a moderate storm event (wave height at 3-4 m) and (2) how a sand bar in the nearshore migrates to the shoreline and drives the shoreline shift.
ISSN: 1760-8716

hal-00854402
https://hal.archives-ouvertes.fr/hal-00854402
DOI : 10.5150/jngcgc.2012.023-C

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : SUBDUNE v0.6 is a very preliminary version of an exploratory model designed tocompute the sea level to the shoreline, combining the effects of various physics, from run-up to tides. It aims at providing an easy-to-use and quick way to estimate water elevation to the beach, assuming morphology is known. Combined with accurate beachdata, such as LIDAR, this engineering tool may provide with end-users an efficient way to quantify submersion.
ISSN: 1760-8716

hal-00854170
https://hal.archives-ouvertes.fr/hal-00854170
DOI : 10.5150/jngcgc.2012.022-B

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : The present work concerns cuspate spits: slightly symmetrical geomorphic features growing along the shoreline in shallow waters. We develop a new formulation for the dynamics of cuspate spits. Our approach relies on classical paradigms such as a conservation law to the shoreface scale and an explicit formula for alongshore sediment transport. We derive a non-linear diffusion equation and a fully explicit solution for the growth of cuspate spits. From this general expression, we found interesting applications to quantify shoreline dynamics in the presence of cuspate spits. In particular, we point out a simple method for the datation of a cuspate spit given a limited number of input parameters. Furthermore, we develop a method to quantify the mean alongshore diffusivity along a shoreline perturbed by well-defined cuspate spits of known sizes. Finally, we introduce a formal relationship between the geometric characteristics (amplitude, length) of cuspate spits, which reproduce the self-similarity of these geomorphic features.
ISSN: 0749-0208

hal-01234952
https://hal.archives-ouvertes.fr/hal-01234952
DOI : 10.2112/SI70-009.1

Éditeur(s) : The Royal Society
Résumé : One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic products commenced in the 1950s, plastic debris has accumulated in terrestrial environments, in the open ocean, on shorelines of even the most remote islands and in the deep sea. Annual clean-up operations, costing millions of pounds sterling, are now organized in many countries and on every continent. Here we document global plastics production and the accumulation of plastic waste. While plastics typically constitute approximately 10 per cent of discarded waste, they represent a much greater proportion of the debris accumulating on shorelines. Mega- and macro-plastics have accumulated in the highest densities in the Northern Hemisphere, adjacent to urban centres, in enclosed seas and at water convergences ( fronts). We report lower densities on remote island shores, on the continental shelf seabed and the lowest densities (but still a documented presence) in the deep sea and Southern Ocean. The longevity of plastic is estimated to be hundreds to thousands of years, but is likely to be far longer in deep sea and non-surface polar environments. Plastic debris poses considerable threat by choking and starving wildlife, distributing non-native and potentially harmful organisms, absorbing toxic chemicals and degrading to micro-plastics that may subsequently be ingested. Well-established annual surveys on coasts and at sea have shown that trends in mega- and macro-plastic accumulation rates are no longer uniformly increasing: rather stable, increasing and decreasing trends have all been reported. The average size of plastic particles in the environment seems to be decreasing, and the abundance and global distribution of micro-plastic fragments have increased over the last few decades. However, the environmental consequences of such microscopic debris are still poorly understood.
Philosophical Transactions of the Royal Society B (0962-8436) (The Royal Society), 2009-07 , Vol. 364 , N. 1526 , P. 1985-1998

Droits : The Royal Society 2009
http://archimer.ifremer.fr/doc/2009/publication-6952.pdf
DOI:10.1098/rstb.2008.0205
http://archimer.ifremer.fr/doc/00000/6952/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Past studies have shown that high coastal uplift rates are restricted to active areas, especially in a subduction context. The origin of coastal uplift in subduction zones, however, has not yet been globally investigated. Quaternary shorelines correlated to the last interglacial maximum (MIS 5e) were defined as a global tectonic benchmark (Pedoja et al. (2011)). In order to investigate the relationships between the vertical motion and the subduction dynamic parameters, we cross-linked this coastal uplift database with the "geodynamical" databases from Heuret (2005), Conrad and Husson (2009) and Müller et al. (2008). Our statistical study shows that: [1] the most intuitive parameters one can think responsible for coastal uplift (e.g., subduction obliquity, trench motion, oceanic crust age, interplate friction and force, convergence variation, dynamic topography, overriding and subducted plate velocity) are not related with the uplift (and its magnitude); [2] the only intuitive parameter is the distance to the trench which shows in specific areas a decrease from the trench up to a distance of ~300 km; [3] the slab dip (especially the deep slab dip), the position along the trench and the overriding plate tectonic regime are correlated with the coastal uplift, probably reflecting transient changes in subduction parameters. Finally we conclude that the first order parameter explaining coastal uplift is small-scale heterogeneities of the subducting plate, as for instance subducting aseismic ridges. The influence of large-scale geodynamic setting of subduction zones is secondary.
ISSN: 0264-3707

hal-00968538
https://hal.archives-ouvertes.fr/hal-00968538
https://hal.archives-ouvertes.fr/hal-00968538/document
https://hal.archives-ouvertes.fr/hal-00968538/file/henryterraces_v2.pdf
DOI : 10.1016/j.jog.2014.04.001

Éditeur(s) : EDP Sciences
Résumé : Monitoring the abundance of green turtles (Chelonia mydas) is necessary to assess population trends and risks of collapse. This note presents a study aimed at comparing three techniques for the direct estimation of green turtle numbers in their foraging habitats (seagrass beds and reef flats). The experiment was carried out at Mayotte Island, Western Indian Ocean. The techniques involved were surveys by snorkel, and aerial surveys using a microlight aircraft and a paramotor. Each technique had shortcomings and advantages. While each technique provided estimations of turtle numbers only surveys by snorkel permitted identification of species and sex, whenever visibility and turtle behaviour permitted. Along the shorelines, and over foraging areas, the paramotor was found to be most suitable for direct estimations of turtle numbers. The major advantage of this technique lied in its capability to obtain a synoptic snapshot of turtle distribution over foraging areas. Linear surveys from a microlight aircraft are better suited to monitor foraging areas located further away from the shore.
Le suivi de l'abondance de tortues vertes (Chelonia mydas) est nécessaire pour évaluer l'évolution et éventuellement, le risque d'extinction des populations. L'objectif de cette expérience est de comparer trois techniques d'observation permettant l'évaluation directe de l'abondance totale de tortues vertes sur les aires d'alimentation (herbiers et platiers récifaux). L'étude a été conduite à l'île de Mayotte (ouest de l'océan Indien). Les techniques testées sont le comptage sous-marin et les comptages aériens à partir d'un ultra léger motorisé (ULM) et d'un paramoteur. Les limites de chaque technique utilisée ont été mises en évidence. L'abondance totale des tortues a été estimée par les trois techniques. Seuls, les comptages sous-marins ont permis de préciser des caractéristiques biologiques tels que l'espèce et le sexe, lorsque les conditions de visibilité et le comportement des tortues le permettaient. Le paramoteur paraît le plus adapté pour une estimation directe de l'abondance sur les aires d'alimentation situées à proximité immédiate de la côte. Cette technique permet de disposer d'un état de la répartition des tortues sur les aires d'alimentation à un moment donné. Pour les zones d'alimentation plus éloignées de la côte, l'usage de l'ULM est nécessaire pour réaliser les comptages à partir de transects linéaires.
Aquatic Living Resources (0990-7440) (EDP Sciences), 2005-04 , Vol. 18 , N. 2 , P. 193-198

Droits : EDP Sciences, IFREMER, IRD 2005
http://archimer.ifremer.fr/doc/2005/publication-432.pdf
DOI:10.1051/alr:2005021
http://archimer.ifremer.fr/doc/00000/432/

Éditeur(s) : HAL CCSD
Résumé : Shoreline and upper beach dynamics under extreme events: the KUNSHEN experiment (Wan Tzu Liao barrier, Taiwan)
PARALIA génie civil & génie côtier

hal-00861950
https://hal.archives-ouvertes.fr/hal-00861950

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : The Gold Coast in Australia is one of these coastal places, which developed through taking advantage of its environmental assets, such as direct access to the sea, a white sandy shoreline, an extensive and naturally protected broadwater and several large accessible rivers. While many other coastal cities relied on port facilities to develop commercial and naval activities, the City of Gold Coast emerged and grew as a tourism destination. Largely because of this phenomenon, the pattern of settlement and subsequent development of the city differs from most traditional Australian settlement and development patterns. Today, the Gold Coast is one of the most famous tourist cities in Australia and it accommodates more than ten million visitors annually.In the wider Australian context, 85% of the population lives within 50 km of the beach, evidencing popular lifestyle cultural preferences of many Australians. Given this preoccupation with the coast, one may expect that Australia would be at the forefront of coastal tourism developments and coastal protection. There is, however, no overriding jurisdiction covering planning law enforcement in maritime areas and, this situation has led to many social and environmental conflicts. The City of Gold Coast is a case in point and no more so than currently (2017) with proposals to build a cruise terminal or/and a casino, and high rise residential towers on its protected coastal strip (the Spit).This paper demonstrates how the evolution and resolution of development conflicts on the Spit (Gold Coast) are symptomatic of the evolution of place values and the national coastal management and how, this informs a shift towards coastal protection.
La ville côtière de Gold Coast, en Australie, s’est développée grâce à un environnement naturel exceptionnel, qui comprend un accès direct à la mer, un littoral de sable blanc, une large baie naturellement protégée et plusieurs rivières. Si la plupart des autres villes du littoral australien se sont appuyées sur leur port pour développer leurs activités commerciales et navales, la ville de Gold Coast est, depuis ses débuts, une ville touristique. De ce fait, son mode et ses formes de développement se différencient de ceux que l’on rencontre traditionnellement dans les autres villes. Aujourd’hui la ville de Gold Coast est l’une des principales destinations touristiques australiennes et accueille plus de dix millions de visiteurs par an.En Australie, 85% de la population habite dans un rayon de 50km de la plage, avec les préférences de style de vie qui y sont associées. Vu cette attraction pour le littoral, on pourrait présumer que l’Australie soit à l’avant-garde des développements touristiques et de la protection de son littoral. Cependant, du point de vue national, comme, historiquement, il n’y a eu qu’une faible jurdiction concernant l’aménagement et la protection des zones maritimes et du littoral, de nombreux conflits sociaux et environmentaux ont vu le jour. La ville de Gold Coast concentre malheureusement nombre de ces conflits ; le dernier en date concernant le projet de construction d’un terminal de bateaux de croisière et/ou d’un casino avec quelques tours residentielles sur une langue de terre protégée (le Spit).L’objectif de cet article est de montrer comment l’évolution et la résolution des conflits sur le Spit de Gold Coast, tous liés à des projets de développements touristiques, reflètent non seulement l’évolution de la valeur d’un lieu et l’approche nationale du développement du littoral, mais aussi le changement vers une meilleure protection du littoral.
Australie

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.10496
http://journals.openedition.org/etudescaribeennes/10496

Éditeur(s) : HAL CCSD
Résumé : International audience
The present work concerns cuspate spits: slightly symmetrical geomorphic features growing along the shoreline in shallow waters. We develop a new formulation for the dynamics of cuspate spits. Our approach relies on classical paradigms such as a conservation law to the shoreface scale and an explicit formula for alongshore sediment transport. We derive a non-linear diffusion equation and a fully explicit solution for the growth of cuspate spits. From this general expression, we found interesting applications to quantify shoreline dynamics in the presence of cuspate spits. In particular, we point out a simple method for the datation of a cuspate spit given a limited number of input parameters. Furthermore, we develop a method to quantify the mean alongshore diffusivity along a shoreline perturbed by well-defined cuspate spits of known sizes. Finally, we introduce a formal relationship between the geometric characteristics (amplitude, length) of cuspate spits, which reproduce the self-similarity of these geomorphic features.
13th International Coastal Symposium
Durban, South Africa

hal-01006569
https://hal.archives-ouvertes.fr/hal-01006569
https://hal.archives-ouvertes.fr/hal-01006569/document
https://hal.archives-ouvertes.fr/hal-01006569/file/JCR_SI_70_009_Bouchette_et_al.pdf

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : International audience
The central part of the Gulf of Lions shoreline is characterized by many coastal wetlands that resulted from the interaction between a process of shoreline regularization by migrations of littoral barriers and a slow filling of the back-barrier areas by the riverine and marine inputs. Analyses of Late-Holocene deposits with a very high-resolution multi-proxy study of two sediment cores, allow us to reconstruct the evolution of this coastal system. Two main Holocene sediment units are identified overlying a Pliocene carbonate continental formation. The lower unit consists of sandy and pebbly marine sediments deposited around 7800 B.P., during the final stand of the last sea level rise. Just above, the upper unit displays lagoonal grey clay silts with shells and some intercalated layers of silty sands related to paleostorm events. The age model was established from radiocarbon dating, for the oldest part of the core. Over the last century, sedimentation rates were calculated using the CFCS Pb-210 model, together with Cs-137 data. Radiocarbon data show an increase in he accumulation rate from the base to the top of cores. Marine sand units related to the last transgressive deposit allow to refine the curve of Holocene post-glacial sea level rise. Sedimentological and faunal analyses associated with chronological data provide a means for reconstructing the Late-Holocene paleoenvironments along this part of the coast and suggest that the final closure of the coastal lagoon by the sandy barrier occurred at around 730 +/- 120 yr cal B.P. The beginning of this closure, together with the progradation of the coastal plain, could be responsible for the decline in economic activity of the Lattara harbour during the Roman period.
La partie centrale du littoral du golfe du Lion est caractérisée par de nombreuses lagunes qui résultent de l'interaction entre un processus de régularisation du trait de côte par migration de barrières littorales et d'un lent remplissage des zones situées en arrière des barrières par des apports continentaux et marins. Les analyses des dépôts tardi-holocènes avec une étude multi-traceurs à très haute résolution de deux carottes sédimentaires nous permettent de reconstruire l'évolution de ce système côtier. Deux unités sédimentaires holocènes sont identifiées recouvrant une formation pliocène carbonatée. L'unité inférieure est constituée de sables et de galets d'origine marine déposés vers 7800 B.P., durant les stades ultimes de la dernière remontée marine. Audessus, l'unité supérieure montre des dépôts d'argile et de silt gris coquilliers d'origine lagunaire, dans lesquels sont intercalés des niveaux de sable silteux révélant la présence d'événements de tempêtes. Le modèle d'âge est établi à partir de dates radiocarbones pour les parties les plus anciennes des archives sédimentaires, tandis que pour le dernier siècle, les taux de sédimentation sont calculés en utilisant le modèle CFCS pour le 210Pb, associé aux données de 137Cs. Les données 14C montrent une augmentation du taux d'accumulation depuis la base jusqu'en surface des carottes. Les unités de sables marins liées aux dépôts de la dernière transgression marine permettent de préciser la courbe post-glaciaire de remontée du niveau marin. Les analyses sédimentologiques et faunistiques associées aux données chronologiques fournissent une méthode permettant de reconstituer les paléoenvironnements littoraux tardi-holocènes dans la zone d'étude et suggèrent que la fermeture finale de ces lagunes par le cordon sableux survient autour de 730 ± 120 ans cal B.P. Le début de cette fermeture, associée à la une progradation deltaïque, pourrait être responsable du déclin des activités économiques du port de Lattara durant la période Romaine.
EISSN: 1777-5817

halshs-00740923
https://halshs.archives-ouvertes.fr/halshs-00740923
DOI : 10.2113/gssgfbull.181.1.27

Éditeur(s) : HAL CCSD
Résumé : Les variations de la ligne de rivage à toutes les échelles comportent des informations fondamentales sur la dynamique du système côtier et son évolution morphologique. Nous avons étudié l'évolution de la ligne de rivage de la côte algéroise sur une longueur de 60 km, allant de l'embouchure de l'oued Réghaïa à l'est, à l'embouchure de l'oued Mazafran à l'ouest. Les variations de la ligne de rivage le long de cette portion côtière ont été obtenues à partir de photographies aériennes orthorectifiées et géo-référencées prises entre 1959 à 2003. Les fluctuations du taux net de variation sont évaluées durant les périodes 1959 -1999 pour les lignes de la côte ouest et de la Baie d'Alger, et 1959- 2003 pour la côte est. L'analyse spectrale par Transformée de Fourier des fluctuations du taux net de variation pour les trois lignes de rivage, montre un comportement en loi d'échelle, caractéristique des signaux stochastiques non stationnaires auto affines. Cette observation nous a conduit à utiliser une Transformée en Ondelettes Continue comme outil d'analyse des fluctuations des lignes de côte le mieux adapté pour quantifier l'existence de corrélations à longue portée associées aux propriétés d'invariance d'échelle que présentent ces signaux. En effet, les exposants de la loi d'échelle estimés par Transformée en Ondelettes Continue pour chacune des trois lignes de rivage qui font l'objet de l'étude varient localement dans l'intervalle [1,23, 1,80], confirmant ainsi les propriétés d'autoaffinité associées aux corrélations à longue portée de ces fluctuations. L'observation des propriétés d'auto-affinité suggère fortement que ces corrélations sont liées aux phénomènes d'érosion- accrétion de l'évolution du trait de côte, en relation avec le processus de réplication du transport des sédiments par un modèle stochastique de diffusion. Dans ce contexte, le point d'intérêt de notre démarche est d'apporter des éléments prédictifs de l'évolution morphologique de cette côte à l'échelle décennale pour une meilleure gestion et prévision des risques littoraux.
Bulletin du Service Géologique National

hal-00463846
https://hal.archives-ouvertes.fr/hal-00463846

Éditeur(s) : HAL CCSD Blackwell Publishing
Résumé : International audience
In the Causses platform (south-east France), Late Hettangian to Sinemurian deposits were interpreted previously as shallow-water carbonate ramp deposits. A new look at these deposits has shown a fault-controlled mosaic carbonate platform that is different from the carbonate ramp models. Within the platform mosaic, 15 lithofacies have been recognized, which are organized in four facies associations, including peritidal, restricted shallow sub-tidal, sand dunes and sub-tidal shelf facies associations. The rapid lateral and vertical facies changes, and the lack of consistent landward or seaward direction indicated by the pattern of facies changes, question the existence of a shoreline suggested by the traditional models for this region. Instead, the facies organization and cycle stacking pattern suggest deposition in a mosaic of intertidal islands between which sub-tidal restricted or open conditions could coexist in very close proximity. Such a platform mosaic would have been defined by tectonic activities along normal faults which segmented the shallow-water Causses platform. The facies and facies associations are arranged into metre-scale, peritidal and sub-tidal cycles that are also variable. Certain cycles show the same stacking pattern in all the sections and seem to be traceable over tens of kilometres. On the contrary, other cycles cannot be correlated; they are present only in specific sections and have a maximum lateral extension of 1 or 2 km. These metre-scale cycles stack to form four medium-scale cycles bounded by surfaces that display sub-aerial exposure features. Medium-scale cycles stack into two larger-scale cycles (tens of metres thick) and are bounded by well-defined karstic surfaces. Based on their lateral continuity and their stacking pattern, the metre-scale cycles are controlled probably by high frequency eustatic variations overprinting the topographic irregularities formed by differential subsidence of fault-bounded blocks. Episodic fault activities may reorganize the topography so that, even if eustatic changes may still be the major control of cycles, the expression and number of cycles could be different. Cycles of medium and large-scale are interpreted as being allogenic, controlled by changes in eustasy and/or subsidence rates as evidenced by their lateral continuity and the correlations of the large-scale cycles with third-order depositional sequences.
ISSN: 1469-3496

hal-00411940
https://hal.archives-ouvertes.fr/hal-00411940
DOI : 10.1111/j.1365-3091.2007.00896.x

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : Barrier island hydro-morphodynamics driven by typhoon events are the major concern of the project KUNSHEN (2011-2014). It aims at providing for a deep understanding of the peculiar dynamics of sand barriers where extreme events such as typhoons have a significant impact. We present the campaigns and the protocols achieved and planned in the project, on the Wan-tzu-liao sand barrier, Cigu Lagoon, Tainan, Taiwan, from October 2011 to January 2012, during the winter storm season and during summer 2012 during the typhoon season. A set of current profilers are deployed along a cross shore transect at 7, 4 and 2 meters deep. On the Wan-tzu-liao sand barrier, 3 columns of 3 pressiometers are deployed to survey the submersion. In the same time, morphological surveys are performed on the sand barrier with DGPS to analyse any change in the shoreline position, the beach slope, and the dynamics of sand beach features. A very preliminary analysis on these on-going field surveys suggests that the word "extreme" refers more to the consequence of the forcing on the sand barrier than the intensity of the forcing itself. The strategy developed in this first step will be refined to survey the next typhoon season, from May 2012 to October 2012.
ISSN: 1760-8716

hal-00854411
https://hal.archives-ouvertes.fr/hal-00854411
DOI : 10.5150/jngcgc.2012.034-M

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
P>Tehran is one of the largest cities in the world (12 million people) facing seismic hazard. Standing at the foothills of Alborz Mountains, the capital of Iran is exposed to potential earthquakes associated with several nearby active faults. Classically mentioned as active features, the Kahrizak, the North Rey and the South Rey scarps cross the town itself and would be the sources of several destructive historical earthquakes. However, the nature of these topographic scarps remains uncertain. To assess whether these features correspond to active faults, we carried out a morphological and stratigraphic study. Our results show that the three scarps define horizontal scarp lines that follow contour lines matching ancient shorelines further East. This point, associated with other morphological characteristics such as the flatness of the upper and the lower surfaces, the long and regular streams that incised the upslope upper surfaces and the fact that the deposits are horizontal and without deformations, suggests in fact that the Kahrizak, the North Rey and the South Rey scarps correspond most likely to ancient shore lines and are not fault scarps.
ISSN: 0954-4879

hal-00496390
https://hal.archives-ouvertes.fr/hal-00496390
DOI : 10.1111/j.1365-3121.2010.00938.x

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The New Jersey continental shelf extends 150 km off the shoreline. During IODP Expedition 313, siliciclastic deposits of late Eocene to late Pleistocene age were drilled down to 631, 669 and 755 m below seafloor at sites 27A, 28A and 29A respectively in very shallow waters (33.5 to 36 m depth). Pore water salinities display multilayered brackish-salty-brine units 10 to 170 m thick, where low-salinity water is preferentially stored in fine-grained sediments. The sharp boundaries of these buried aquifers are often marked by cemented layers a few centimetres thick. The mineralogy and scanning electron microscope observations of these layers show two phases of cementation by authigenic minerals: (1) the early carbonate cement is frequently associated with pyrite, and (2) the late silicate cement infills the residual porosity. The isotopic compositions of the carbonate cements vary widely: −2.4 < δ¹⁸O ‰ VPDB < +2.8; −15.1 < δ¹³C ‰ VPDB < +15.6. The δ¹⁸O values indicate that the carbonate cements precipitated with pore waters comprising variable mixtures of seawater and ¹⁸O-depleted fresh water originating from submarine groundwater discharge. The δ¹³C values of the carbonate cements are related to organic matter diagenesis, providing ¹³C-depleted dissolved inorganic carbon during bacterial sulphate reduction and anaerobic oxidation of methane, and ¹³C-rich dissolved inorganic carbon during methanogenesis. The diagenetic cementation processes included chemical weathering of reactive silicate minerals by the CO²-rich pore waters issued from organic matter diagenesis that released bicarbonate, cations and dissolved silica, which were further precipitated as carbonate and silicate cements. The estimated range of temperature (18±4 °C) during carbonate precipitation is consistent with carbonate cementation at moderate burial depths; however, silicate cementation occurred later during diagenesis at deeper burial depths.
ISSN: 0276-0460

hal-01559985
https://hal.archives-ouvertes.fr/hal-01559985
DOI : 10.1007/s00367-017-0506-6

Éditeur(s) : HAL CCSD
Résumé : Quasi-3D model SHORECIRC simulates circulation on simple nearshore domains. It is modified in order to handle realistic bathymetries : beaches with complex shoreline and/or emerged structures. Added improvements are validated against other models and measurements on various configurations. New SHORECIRC version is then applied to the study of the circulation dynamics of Leucate, a sandy beach of Languedoc- Roussillon (France) with crescentic bars.
Le modèle numérique de circulation quasi-tridimensionnel SHORECIRC, initialement prévu pour fonctionner sur des bathymétries simples, a été modifié afin de pouvoir prendre en compte les caractéristiques complexes des bathymétries réalistes de la zone littorale : trait de côte irrégulier et présence d'objets émergés. Les modifications apportées ont ´été validées par comparaison avec des résultats d'autres modèles numériques et avec des données mesurées sur plusieurs configurations. Enfin, le modèle modifié a été appliqué à l'étude de la dynamique de la circulation sur une plage sableuse à barres en festons (Plage de Leucate, Languedoc-Roussillon, FR).
https://tel.archives-ouvertes.fr/tel-00438713

tel-00438713
https://tel.archives-ouvertes.fr/tel-00438713
https://tel.archives-ouvertes.fr/tel-00438713/document
https://tel.archives-ouvertes.fr/tel-00438713/file/thesebujan.pdf

Éditeur(s) : HAL CCSD Société nationale de protection de la nature
Résumé : International audience
The island of Moorea in French Polynesia is representative of a relatively well preserved small tropical oceanic island but both its terrestrial and marine ecosystems are currently under strong anthropogenic pressures. The terrestrial ecosystems are facing an increasing urbanization, and the destruction and modification of their natural habitats by cultivation and forestry plantations, accidental or intentional fires, and particularly by the invasion of alien plant and animal species. Coastal areas and reef ecosystems are threatened by shoreline artificialization, sedimentation due to soil erosion, increasing uses of marine and lagoon resources and frequency of coral bleaching events. A significant erosion of terrestrial and marine biodiversity is observed on the island since the last decades. In the context of the Land Management Plan (PGA) and Marine Area Management Plan (PGEM) recently set up in the island by local authorities, scientific surveys and inventories were made in 2006 in order to assess the status of terrestrial biodiversity (vascular plants) and marine biodiversity (reef fishes) and compare areas with different anthropogenic pressures. Studies conducted on the flora and the vegetation at low and middle elevation along altitudinal transects show that the plant invasion process is related to climatic and topographic factors, and species autoecology. The marine study aims to compare the protected areas with control areas in order to test the effectiveness of protection measures and to propose a streamlined monitoring protocol. A methodological study in both terrestrial and marine ecosystems was conducted in order to propose biodiversity indicators which are crucial for decision making in conservation and sustainable development of island biodiversity. We used Geographic Information System (GIS) as a fast and intuitive tool for mapping indicators and their variability. This methodological approach developed on the island of Moorea could be used as a model for other tropical islands
Moorea est une petite île océanique tropicale de la Polynésie française relativement bien préservée, mais dont les écosystèmes terrestres et marins sont actuellement soumis à de fortes pressions anthropiques. Le milieu terrestre est confronté à une urbanisation croissante, à la destruction ou à la modification des habitats naturels pour l’extension des cultures ou des plantations forestières, aux incendies volontaires ou accidentels, et particulièrement à l’invasion d’espèces végétales et animales introduites. Les zones côtières et les récifs coralliens sont menacés par de multiples perturbations telles que l’artificialisation des lignes de rivage, l’apport de sédiments dus à l’érosion des sols, l’augmentation des usages des ressources marines et lagonaires et de la fréquence des phénomènes de blanchissement du corail. Une érosion sensible de la biodiversité terrestre et marine de l’île est observée depuis les dernières décennies. Dans le cadre du Plan Général d’Aménagement (PGA) et du Plan de Gestion de l’Espace Maritime (PGEM) mis en place par les autorités locales, des inventaires scientifiques ont été réalisés en 2006 dans le but d’évaluer l’état de la biodiversité terrestre (plantes vasculaires) et marine (poissons récifaux) et de comparer des zones soumises à différentes perturbations. Les études réalisées sur la flore et la végétation de basse et moyenne altitude le long de transects altitudinaux montrent des processus d’invasion végétale différents en relation avec les facteurs climatiques, topographiques et autoécologiques des espèces. Les études en milieu marin visent à comparer des aires protégées à des aires témoins afin de suivre l’efficacité des mesures de gestion. La réflexion méthodologique menée parallèlement sur les deux écosystèmes a pour but d’illustrer différents indices de biodiversité nécessaires à la prise de décision en matière de conservation ou de développement durable de la biodiversité insulaire et de réaliser un état de référence pour établir un diagnostic sur l’état de la biodiversité. La représentation cartographique des indices à l’aide d’un SIG, illustrée dans cette étude avec la richesse spécifique terrestre et marine, permet une lecture intuitive et rapide de la variabilité de cet indice dont la restitution est basée sur une standardisation du nombre d’espèces. Cette approche méthodologique développée sur l’île de Moorea pourrait servir de modèle pour d’autres îles tropicales
EISSN: 2429-6422

hal-01306285
https://hal-univ-perp.archives-ouvertes.fr/hal-01306285

Éditeur(s) : Cambridge Univ Press
Résumé : Integrated Multi-Trophic Aquaculture takes advantage of the mutualism between some detritivorous fish and phytoplankton. The fish recycle nutrients by consuming live (and dead) algae and provide the inorganic carbon to fuel the growth of live algae. In the meanwhile, algae purify the water and generate the oxygen required by fishes. Such mechanism stabilizes the functioning of an artificially recycling ecosystem, as exemplified by combining the euryhaline tilapia Sarotherodon melanotheron heudelotii and the unicellular alga Chlorella sp. Feed addition in this ecosystem results in faster fish growth but also in an increase in phytoplankton biomass, which must be limited. In the prototype described here, the algal population control is exerted by herbivorous zooplankton growing in a separate pond connected in parallel to the fish-algae ecosystem. The zooplankton production is then consumed by tilapia, particularly by the fry and juveniles, when water is returned to the main circuit. Chlorella sp. and Brachionus plicatilis are two planktonic species that have spontaneously colonized the brackish water of the prototype, which was set-up in Senegal along the Atlantic Ocean shoreline. In our system, water was entirely recycled and only evaporation was compensated (1.5% volume/day). Sediment, which accumulated in the zooplankton pond, was the only trophic cul-de-sac. The system was temporarily destabilized following an accidental rotifer invasion in the main circuit. This caused Chlorella disappearance and replacement by opportunist algae, not consumed by Brachionus. Following the entire consumption of the Brachionus population by tilapias, Chlorella predominated again. Our artificial ecosystem combining S. m. heudelotii, Chlorella and B. plicatilis thus appeared to be resilient. This farming system was operated over one year with a fish productivity of 1.85 kg/m(2) per year during the cold season (January to April).
Animal (1751-7311) (Cambridge Univ Press), 2013-02 , Vol. 7 , N. 2 , P. 322-329

Droits : The Animal Consortium 2012
http://archimer.ifremer.fr/doc/00118/22955/20945.pdf
DOI:10.1017/S1751731112001279
http://archimer.ifremer.fr/doc/00118/22955/