Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : The south-west lagoon of New Caledonia is a wide semi-open coral reef lagoon bounded by an intertidal barrier reef and bisected by numerous deep inlets. This paper synthesizes findings from the 2000-2008 French National Program EC2CO-PNEC relative to the circulation and the transport of suspended particles in this lagoon. Numerical model development (hydrodynamic, fine suspended sediment transport, wind-wave, small-scale atmospheric circulation) allowed the determination of circulation patterns in the lagoon and the charting of residence time, the later of which has been recently used in a series of ecological studies. Topical studies based on field measurements permitted the parameterisation of wave set-up induced by the swell breaking on the reef barrier and the validation of a wind-wave model in a fetch-limited environment. The analysis of spatial and temporal variability of suspended matter concentration over short and long time-scales, the measurement of grain size distribution and the density of suspended matter (1.27 kg 1(-1)), and the estimation of erodibility of heterogeneous (sand/mud, terrigenous/biogenic) soft bottoms was also conducted. Aggregates were shown to be more abundant near or around reefs and a possible biological influence on this aggregation is discussed. Optical measurements enabled the quantification of suspended matter either in situ (monochromatic measurements) or remotely (surface spectral measurements and satellite observations) and provided indirect calibration and validation of a suspended sediment transport model. The processes that warrant further investigation in order to improve our knowledge of circulation and suspended sediment transport in the New Caledonia lagoon as well as in other coral reef areas are discussed, as are the relevance and reliability of the numerical models for this endeavour.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2010 , Vol. 61 , N. 7-12 , P. 269-296

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00014/12526/9401.pdf
DOI:10.1016/j.marpolbul.2010.06.023
http://archimer.ifremer.fr/doc/00014/12526/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The biogeochemistry of sulfur and carbon during early-diagenetic processes within organic-rich marine mangrove sediments was studied in the “Manche à Eau” lagoon, Guadeloupe, West Indies. These sediments are characterized by a total organic carbon content (TOC) mostly above 11 wt%, δ13CTOC below − 25‰ VPDB and C/Nmolar ratios exceeding 15. Rates of mangrove-derived organic carbon accumulation vary between ~ 200 and 400 gOC·m− 2·yr− 1, with highest rates at the shore of the lagoon. On the lagoon border, where colorless filamentous sulfur-oxidizing bacteria colonize the sediments, active sulfate reduction within the upper 20 cm, with a net removal rate of ~ 0.5 μmol·cm− 3·d− 1, is assumed to be essentially driven by organic carbon oxidation. This is expressed by relatively low apparent sulfur isotope fractionation (34εnet = − 33‰) and a gentle δ18O/δ34Ssulfate apparent slope of 0.36 ± 0.03 (2s). Further inside the lagoon, in the absence of sulfur-oxidizing bacteria, higher apparent sulfur isotope fractionation and a steeper δ18O/δ34Ssulfate slope (0.67 ± 0.20) suggest an overall lower sulfate removal rate that may be coupled to minor sulfur disproportionation. Spatial and vertical variation in sulfur cycling, reflected by oxygen and sulfur isotopic characteristics, seem to be mainly controlled by unsteady to relatively steady organic matter deposition and its reactivity. In all sediments, δ34S values of pyrite are positively correlated with the TOC/TS ratio and negatively correlated with δ13CTOC; suggesting a primary control of the quantity and quality of organic matter on the pyrite isotope records, despite potential iron-limiting conditions for the most active sites. Our results provide insights into the role of organic carbon input on sulfur cycling; stimulating sulfate reduction and in turn the presence of sulfur-oxidizing microbial mats, resulting in an intense cycling of both carbon and sulfur in these marine mangrove sediments.
ISSN: 0009-2541

hal-01507696
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01507696
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01507696/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01507696/file/Cr%C3%A9mi%C3%A8re%20et%20al.%20-%20Sulfur%20diagenesis%20under%20rapid%20accumulation%20of%20orga.pdf
DOI : 10.1016/j.chemgeo.2017.02.017

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 Elsevier
Résumé : International audience
Understanding long-term variability in the frequency of intense storm activity is important for assessing whether changes are controlled by climate evolution. Understanding this variability is also important for predicting present and future community vulnerability and economic loss. Our ability to make these assessments has been limited by the short (less than 50 years) instrument record of storm activity. Storm-induced deposits preserved in the sediments of coastal lagoons offer the opportunity to study the links between climatic conditions and storm activity on longer timescales. In this study, we present a record of these extreme climatic events that have occurred in the French Mediterrannean coast over the past 1500 years. The identification of these extreme events is based on the analysis of sediment cores from Gulf of Aigues-Mortes lagoons that contain a specific sedimentary and geochemical signature associated with intense storms.;Overwash deposits do not show any evidence of intense storm landfalls in the region for several hundred years prior to the late 17th century A.D. The apparent increase in intense storms around 250 years ago occurs during the latter half of the Little Ice Age, a time of lower continental surface temperatures. Comparison of the sediment record with palaeoclimate records indicates that this variability was probably modulated by atmospheric dynamics. The apparent increase of the superstorm activity during the latter half of the Little Ice Age was probably due to the thermal gradient increase leading to enhanced lower tropospheric baroclinicity over a large Central Atlantic/European domain and leading to a modification of the occurrence of extreme wind events along the French Mediterranean coast. A complete understanding of the relationship between climate fluctuations, storm activity, and the coastal response will be crucial to predicting the impacts of future climate change.
ISSN: 0031-0182

hal-00617525
https://hal.archives-ouvertes.fr/hal-00617525
DOI : 10.1016/j.palaeo.2010.11.009

Résumé : In the booming context of shrimp culture in French Caledonia, some research actions need to be considered in order (i) to make sure this production will not impact the quality and biodiversity of the coastal environment it is contingent upon (ii) for the field to highlight, based on objective bases, its good "environmental image", for an efficient commercialization of its products. In the framework of the MOM project, a number of actions have been carried out: Action 1: A bibliographical synthesis of the impact of shrimp culture on coastal environment has been conducted, taking into account the works carried out throughout the world and in French Caledonia in order to draw the main issues the Territory will have to deal with. It seems necessary to start with an assessment of the future and the impact of the effluents on the coastal environment. Action 2: With this aim in mind, one or more indicators, among the lagoon's environmental variables, of the influence of the farms' rejects on the coastal environment, have been searched for. The first results are presented in this report. Action 3: In parallel, a long-term program taking into account the different aspects of the problem in its entirety and complexity has been defined in relation with our partners in French Caledonia. With this aim in mind, a symposium entitled "Ecosystems and shrimp culture", organised by the Ifremer in French Caledonia, with the support of the IRD, was held in Nouméa from June 22nd to June 24th, 2005. This symposium enabled the drawing out of the research perspective on the benthos, on the functioning of the lagoon ecosystem, and on the evolution of the mangrove swamps subjected to organic matter inflows from farms.
Dans un contexte d'essor de la filière crevette de Nouvelle Calédonie, des actions de recherche doivent être envisagées (i) pour assurer que cette production n'hypothéquera pas la qualité de l'environnement littoral et sa biodiversité dont elle dépend et (ii) pour que la filière puisse mettre en avant, sur des bases objectives, son image «environnementalement correcte» garante de la bonne commercialisation de son produit. Dans le cadre de ce projet MOM, plusieurs actions ont été menées : Action 1 : Une synthèse bibliographique de l'impact de l'aquaculture de crevettes sur l'environnement littoral a été réalisée en prenant en compte les travaux conduits à travers le monde et en Nouvelle-Calédonie afin de dégager les principales problématiques concernant le Territoire. Il apparaît nécessaire comme première priorité d'être capable d'évaluer le devenir et l'impact des effluents sur l'environnement littoral. Action 2 : A ce titre, un travail de recherche d'un ou de plusieurs indicateurs, parmi les variables environnementales du lagon, de l'influence des rejets aquacoles sur l'environnement littoral a été mené. Les premiers résultats sont présentés dans ce rapport. Action 3 : Parallèlement, il a été défini en relation avec nos partenaires présents en Nouvelle-Calédonie un programme pluriannuel prenant en compte les différents aspects du problème dans sa globalité et sa complexité. Pour cela, un séminaire intitulé « Écosystèmes et crevetticulture » organisé par l'Ifremer en Nouvelle-Calédonie avec le soutien de l'IRD s'est tenu à Nouméa du 22 au 24 juin 2005. Ce séminaire a permis d'élaborer des perspectives de recherche sur le benthos, sur le fonctionnement de l'écosystème lagon et sur l'évolution des mangroves soumis à des apports de matière organique issus des élevages.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/rapport-6593.pdf
http://archimer.ifremer.fr/doc/00000/6593/

Éditeur(s) : HAL CCSD Western Indian Ocean Marine Science Association
Résumé : International audience
Juan de Nova is one of the scattered islands known as Iles Eparses in the Mozambique Channel (Western Indian Ocean). Historically, they have been isolated from many anthropogenic influences which makes them ideal areas to study biodiversity for comparison with areas that are heavily impacted by urbanization and fishing. The programme BioReCie (Biodiversity, Resources and Conservation of Eparses Islands) undertook inventories of several marine groups, including echinoderms, which had hitherto not been assessed in Juan de Nova. A multidisciplinary team surveyed the reef slopes of the island using SCUBA to a depth of 25 m as well as the reef flats at low tide, collecting specimens and taking photos for identification. Sixty echinoderm species were found, with 51 occurring on the reef flats and in the lagoon and 22 on the reef slopes, comprising 21 species of Holothuroidea, 16 Ophiuroidea, 10 Echinoidea, 7 Asteroidea, and 6 Crinoidea. Commercial species of Holothuroidea, some of which are classified as endangered in the IUCN red list, i.e. Thelenota ananas and Holothuria nobilis, were present on the reef flats, reef slopes and in the lagoon of the island, indicating the value that protection has on biodiversity.
ISSN: 0856-860X

hal-01306709
http://hal.univ-reunion.fr/hal-01306709
http://hal.univ-reunion.fr/hal-01306709/document
http://hal.univ-reunion.fr/hal-01306709/file/A%20First%20Inventory%20of%20Echinodermata%20at%20Juan%20de%20Nova_hal.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) : HAL CCSD Elsevier
Résumé : International audience
The marine Messinian deposits of Tunisia cover a narrow littoral strip some 300 km long between the northern Bizerte and Cap Bon areas and the central-eastern Sahel region. Litho- and biofacies analysis of six stratigraphic sections reveals the distinctive features of these deposits.;The lower Messinian deposits are characterized by ubiquitous siliciclastics and abundant oolitic/bioclastic limestones organized in an eastward facing ramp. Westward (landward), this ramp changes into coastal lagoons, sometimes containing evaporites. Eastward, the ramp passes to the reefal Pelagian Platform extending as far as Lampedusa.;Two main sedimentary cycles are distinguished: 1) an early Messinian siliciclastic retrogradational then oolitic/bioclastic progradational cycle (Beni Khiar Formation and lower Oued bel Khedim Formation): 2) a late Messinian brackish to continental cycle that probably accumulated in rapidly subsiding lagoons (Cued el Bir Formation and upper Oued bel Khedim Formation). The Tunisian early Messinian cycle is partly eustatically controlled, but the late Messinian cycle cannot be confidently correlated to other well-known Messinian series because of tectonic movements.;The lower Messinian deposits of Tunisia are also characterized by abundant suspension-feeding organisms (molluscs and bryozoans) and rare corals, calcareous algae, echinoids, and larger benthic foraminifers. The proposed palaeoenvironmental model shows that the lower Messinian ramp of Tunisia was located on a current-protected margin and subjected to continent-derived sediment and nutrient supply. Eastward, nutrient influx diminished and a shallow-water isolated carbonate platform with coralgal facies developed between the western and the eastern Mediterranean basins. The main hydrological connection between these two basins occurred through a narrow seaway situated to the northeast of the Pelagian Platform, south of Sicily and Malta.
ISSN: 0031-0182

hal-00475583
https://hal.archives-ouvertes.fr/hal-00475583
DOI : 10.1016/j.palaeo.2009.10.028

Éditeur(s) : PSIC 11 - 11th Pacific Science Inter-Congress : Pacific Countries and their Ocean: Facing Local and Global Changes / 2nd Symposium on French Research in the Pacific. March 2 - 6, 2009 Tahiti, French Polynesia.
Résumé : Meiofauna is a functional group made of small benthic metazoans 45 to 500µm in size. Although protista, foraminifera living in this kind of environment are often put in to the meiofauna. Meiofauna has been studied in New Caledonia for its double role as biological indicator for monitoring pond health status and as shrimp forage. Suitability of EOM (easily oxidized material), SOD(sediment oxygen demand),as new biochemical tools for monitoring shrimp pond health was assessed in an environmental survey aiming to assess the role of the water/sediment interface in the occurrence of the summer syndrome vibriosis. EOM, SOD and redox were correlated with shrimp survivals. Lowest meiofauna biomass and abundance were concomitantly found in the most polluted station. Proportion of abnormal tests over exceeding the one found in areas subjected to natural ecological stress were collected and were positively related to EOM and SOD and negatively to redox. Shrimp pond dominant species are common to estuaries and lagoons. But foraminifera abnormal behaviour indicates specific shrimp pond conditions

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00198/30876/29244.pdf
http://archimer.ifremer.fr/doc/00198/30876/

Éditeur(s) : HAL CCSD
Résumé : Carbon and Oxygen isotope profiles from a well-dated carbonate section spanning the Sinemurian time on the Caussenard High (southeast France) are compared to sedimentological data and the results from sequence stratigraphy analysis, in order to discuss the origin of isotopic variations in a shallow-marine carbonate succession. The sedimentological study has enabled the identification of four types of depositional environments (peritidal, lagoonal, sand shoal, outer-shelf) that formed meter-scale cycles. The latter are arranged in two third-order cycles whose boundaries correspond to distinct δ13C and δ18O negative peaks (at the end of the Hettangian time and during Middle Sinemurian). The origin of the isotopic signals is discussed and several hypothesis are envisaged: sea water ageing, early meteoric diagenesis. Isotopic curves observed here seems to be related to early meteoric diagenesis linked to variations of third-order sea-level cycles rather than environmental factors (temperature, salinity).
Swiss Journal of Geosciences

hal-00406603
https://hal.archives-ouvertes.fr/hal-00406603
DOI : 10.1007/s00015-007-1206-4

Éditeur(s) : Gauthier-Villars
Résumé : Fish communities from two lagoon ecosystems, Ria Formosa (Portugal) and Grand Cul-de-Sac Marin (Guadeloupe), show interesting similarities of spatial and temporal organization. On the temporal scale, three community changes are observed in both systems, corresponding to massive arrivals and/or departures of migratory species. However, these migrations are more conspicuous in the Ria Formosa than in the Grand Cul-de-Sac Marin. On a spatial scale, the community structure is also largely determined by migratory species, whose abundance is a factor of homogenization. This is clearly observed in Ria Formosa, where the lagoon selection applies on a regional scale. Conversely, the community of sedentary fish identifies remarkable stations affected by chronic aggressions such as tourism or pollution. An explicative analysis, comprising a discriminant analysis and multiple regressions was realized on the data collected in the Grand Cul-de-Sac Marin. This analysis made it possible to determine the important environmental descriptors in the two complementary processes involved in recruitment: migrant availability, which determines the temporal organization of the fish assemblage. These migrations are explained by water temperature and salinity, two descriptors controlled by climatic conditions; the settlement process, which determines the spatial organization of the fish assemblage. This is explained by habitat descriptors such as visibility and turtlegrass blade length, or trophic descriptors, such as primary production, zooplankton density or nitrate concentration.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1993 , Vol. 16 , N. 3 , P. 291-301

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00099/21056/18682.pdf
http://archimer.ifremer.fr/doc/00099/21056/

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 Elsevier
Résumé : International audience
Ciguatera Fish Poisoning (CFP) is a non-bacterial seafood poisoning well characterized in the remote archipelagos of French Polynesia, yet poorly documented in the Society archipelago, most notably on Moorea, the second most populated island in French Polynesia, which counts a high proportion of fishermen fishing on a regular basis. To address this knowledge gap, a holistic study of the ciguatera issue was conducted on Moorea. First, ciguatera risk was analysed in terms of incidence rate, fish species most commonly involved and risk stratification in Moorea lagoon based on 2007–2013 epidemiological data. A mean incidence rate of 8 cases per 10,000 inhabitants for the study period and an average under-reporting rate of 54% were found. Taking into account hospitalization and medication fees, and loss of productive days, the health-related costs due to CFP were estimated to be USD $1613 and $749 for each reported and unreported case, respectively, with an overall cost of USD $241,847 for the study period. Comparison of the present status of CFP on Moorea with a risk map established in the late 1970’s showed that the spatial distribution of the risk has stayed relatively stable in time, with the north shore of the island remaining the most prone to ciguatera. Evaluation of the current knowledge on CFP among different populations groups, i.e. fishermen, residents and visitors, was also conducted through direct and indirect interviews. About half of the fishermen interviewed were actually able to identify risky fishing areas. While, overall, the CFP risk perception in the fishing community of Moorea seemed accurate, although not scientifically complete, it was sufficient for the safe practice of their fishing activities. This may be due in part to adaptive responses adopted by 36% of the fishermen interviewed, such as the avoidance of either high-risk fishing sites or toxic species. At the residents and visitors’ level, the study points out a striking lack of awareness of the CFP issue among visitors, as compared to local residents. Indeed, less than 25% of Moorea visitors vs. an average of 98% in residents were aware of CFP or of its presence on the island. Interestingly, evaluation of the fish consumption preferences showed that 70% of visitors do not consume lagoon fish during their stay, not for fear of CFP, but mainly due to the lack of availability of these species in recreational facilities or because they have nutritional preference for pelagic fish. This lack of awareness, along with the report by several CFP patients of the consumption of fish species yet banned for sale, stress the need for improved communication efforts on this critical issue among both residents and visitors on Moorea. The implementation of a public outreach strategy is proposed, based on both existing information networks and low-cost communication actions through information displays at various strategic locations, e.g. Tahiti-Faa’a international airport, the ferry boat station, recreational facilities, as well as the major trading points on Moorea Island.
ISSN: 1568-9883

hal-01391648
https://hal-univ-perp.archives-ouvertes.fr/hal-01391648
DOI : 10.1016/j.hal.2016.10.003

Résumé : Fishing activity in the french mediterranean lagoon Etang de Berre is actually allowed in spite of a degradation of the environment during the last fifty years. To analyse the results and the working of the fishery, a study based on a sampling survey of catches and fishing effort has been conducted in the various landing ports over a two years period. Annual weight and value productions by species and gear have been evaluated by mean of statistical calculation procedures. The results show that the fishery is based on the exploitation of two main species (anguilla and grey mullet) and that important variations exist between the two sampled years. The limits to be reached by the working of this fishery are prompted in the scope of a future regulation.
La pratique de l'exploitation halieutique dans l'étang lagunaire de Berre (Méditerranée française) est actuellement tolérée malgré la dégradation du milieu au cours des cinquante dernières années. Pour réaliser une analyse des résultats et du fonctionnement de la pêcherie, une étude par enquête basée sur le suivi des captures et des efforts de pêche a été menée aux différents ports de débarquements pendant une durée de deux ans. On calcule par évaluation les productions annuelles spécifiques et par métiers, en poids et en valeurs. Ces résultats montrent que la pêcherie est basée sur l'exploitation de deux espèces principales (anguille et mulets) et qu'il existe de fortes variations entre les deux années d'études. Dans l'optique d'une réglementation on suggère les limites résultant du mode de fonctionnement de cette pêcherie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1989/rapport-1569.pdf
http://archimer.ifremer.fr/doc/00000/1569/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Coral reef resource systems are complex adaptive social-ecological systems providing vital and valuableecosystem services for human societies such as food provision, coastal protection and recreational activities.Their sustainability is questioned in many places around the world as they experience combined effects ofmultiple chronic anthropogenic and natural drivers at local to global scales. From a management perspective,there is a crucial need to understand how the impact of these drivers cascade through the social-ecologicalsystem components. This study develops a transdisciplinary and participatory approach to investigating thesocial-ecological dynamics of a Polynesian coral reef coastal system. A preliminary conceptual model using theDriver-Pressure-State-Impact (DPSI) framework is first being built through participatory modeling workshops.Then, pressure-state relationships are assessed with the help of empirical datasets as a first step towards thevalidation of the DPSI model. Results shows striking social-ecological interactions with different patterns in thelagoon and in the fore reef. Local management should be: (1) less resource-focused to account more specificallyto the existing typology of actors; (2) more spatially-explicit to better distinguish management objectives andactions for the lagoon and the fore reef sub-systems; and (3) more coordinated with terrestrial agencies for acoherent land-sea connection and integration that would both (i) account for existing land-sea interactions and(ii) better reflect the Polynesian cultural heritage that considers nature from ridge to reef as a whole. Suchconceptual models of social-ecological systems are a useful tool to build exploratory scenarios to ultimatelysupport planning decision-making processes.
ISSN: 0308-597X

hal-01491968
https://hal-univ-perp.archives-ouvertes.fr/hal-01491968
DOI : 10.1016/j.marpol.2017.01.014

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Shrimp farming in New Caledonia typically uses a flow-through system with water exchange rates as a tool to maintain optimum hydrological and biological parameters for the crop. Moreover, the effluent shows hydrobiological characteristics (minerals, phytoplankton biomass and organic matter) significantly higher than that of the receiving environment. Separate surveys were carried out in a bay (CH Bay) with a medium-size intensive farm (30 ha) (PO) and in a mangrove-lined creek (TE Creek) near a larger semi-intensive farm (133 ha) (SO). Net loads of nitrogen exported from the semi-intensive farm and the intensive farm amounted to 0.68 and 1.36 kg ha(-1) day(-1), respectively. At CH Bay, discharge effects were spatially limited and clearly restricted to periods of effluent release. The high residence time at site TE favoured the installation of a feedback system in which organic matter was not exported. Mineralization of organic matter led to the release of nutrients, which in turn, caused in an increased eutrophication of this ecosystem. The study of the pico- and nanophytoplankton assemblages showed (i) a shift in composition from picophytoplankton to nanophytoplankton from offshore towards the coast and (ii) a shift within the picophytoplankton with the disappearance of Prochlorococcus and the increase of picoeucaryotes towards the shoreline. These community changes may partially be related to a nitrogen enrichment of the environment by shrimp farm discharges. Thus, in view of the recent addition of the New Caledonian lagoon to the UNESCO World Heritage list, the data presented here could be a first approach to quantify farm discharges and evaluate their impact on the lagoon. (C) 2010 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2010 , Vol. 61 , N. 7-12 , P. 387-398

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/00014/12527/9882.pdf
DOI:10.1016/j.marpolbul.2010.07.005
http://archimer.ifremer.fr/doc/00014/12527/

Éditeur(s) : HAL CCSD
Résumé : Satellite and in situ chlorophyll concentration data collected as part of VALidation HYperspectral of a BIOgeochemical model (ValHyBio), a PNTS-sponsored project dedicated to satellite ocean-colour imaging of the Southwest Pacific, are analyzed to describe chlorophyll variability in the Coral Sea, a vast oligotrophic region characterized by a deep chlorophyll maximum and blue waters of high transparency. Average chlorophyll concentrations estimated from MODIS-Aqua are very low (<0.2 mg m-3) except in the vicinity of main islands and coral reefs, where enrichment may occur due to upwelling or internal waves that bring nutrients to the euphotic zone from the deep part of the water column. During the summer season, blooms of cyanobacteria (Trichodesmium) develop in the surface waters and may form large slicks. The nitrogen fixed by these slicks is a potential source of new nitrogen later assimilated by picoplankton and the marine food chain. Coastal areas exhibit higher chlorophyll concentrations because of nutrient input from the land, as observed in 2008 around New Caledonia. In lagoon areas, the sea colour is influenced by turbidity and bathymetry, and the MODIS OC3 algorithm is inadequate, with a systematic overestimation of chlorophyll concentration in the New Caledonia lagoon. Improved bio-optical algorithms are needed for those turbid and shallow waters, to allow not only a better description of chlorophyll variability, but also evaluation of chlorophyll simulations by recently developed biogeochemical models.
of the 12th International Coral Reef Symposium, 18E
CAIRNS, Australia

hal-00746470
https://hal.archives-ouvertes.fr/hal-00746470
https://hal.archives-ouvertes.fr/hal-00746470/document

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Metazooplankton abundance, biomass (<80 mu m, 200-500 mu m and >500 mu m) and community structure in the Ahe atoll were studied together with their relationships with environmental factors (temperature, salinity, wind) and trophic factors (phytoplankton, bacteria, heterotrophic nanoflagellates (HNF) and ciliates) during three periods in 2008-2009. Meroplankton, mainly bivalve and gastropod larvae, was dominant. Holoplankton was dominated by copepods, the main species being Oithona spp., Paracalanus parvus, Clausocalanus spp., Corycaeus spp., Acartia fossae and Undinula vulgaris. The results suggest a clear wind influence on the structure and horizontal distribution of the zooplankton communities. The metazooplankton appeared to be controlled mainly by food resources, suggesting a bottom-up control. The low nanophytoplankton biomass in contrast to the high abundance of picophytoplankton, HNF and nano-particle grazers (mainly Oithona spp., Paracalanus and bivalve larvae) highlighted the importance of the microbial loop in the food web. (C) 2012 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2012 , Vol. 65 , N. 10-12 , P. 538-548

Droits : 2012 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00101/21207/19419.pdf
DOI:10.1016/j.marpolbul.2012.01.025
http://archimer.ifremer.fr/doc/00101/21207/

Éditeur(s) : HAL CCSD
Résumé : International audience
This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
. Marine Pollution Bulletin

hal-01526382
https://hal.archives-ouvertes.fr/hal-01526382
DOI : 10.1016/j.marpolbul.2017.03.012
PUBMED : 28320509

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
The distribution of the lagoon cockle Cerastoderma glaucum is strongly fragmented and usually restricted to isolated, shallow and nontidal lagoons. A high level of genetic structuring was found among the European populations of this species based on mtDNA (COI) sequences, as well as allozymic and microsatellite markers. However, the strengths and geographic locations of the major divisions differed among markers. In the present study we characterized the diversity of a new, potentially universal exon-primed intron-crossing marker, i34, for 17 C. glaucum populations. Allele frequency data at the i34 locus were informative and relevant with respect to geography. Multivariate analyses of new data together with previously published microsatellites confirmed the divergent character of the Ionian Sea and the Aegean-Ponto-Caspian populations, but also revealed the existence of a genetic cline from the Bay of Biscay to the Baltic Sea. Some noncongruent patterns among loci were detected, which may reflect either differential introgression along the genome at the hypothetical contact zone, or selective sweeps. This strong genetic differentiation, and the occurrence of private alleles, may hint at the presence of cryptic species within C. glaucum.
ISSN: 0260-1230

hal-01444646
https://hal.archives-ouvertes.fr/hal-01444646
DOI : 10.1093/mollus/eyw019