Search

Your search keyword '"Romain Le Gendre"' showing total 20 results
Start Over Author "Romain Le Gendre" Topic 01 natural sciences
20 results on '"Romain Le Gendre"'

1. Shallow Water Bathymetry Retrieval Using a Band-Optimization Iterative Approach: Application to New Caledonia Coral Reef Lagoons Using Sentinel-2 Data

Author

Benoit Soulard, Serge Andréfouët, Sélim Amrari, Hugues Lemonnier, Romain Le Gendre, and Emmanuel Bourassin

Subjects
010504 meteorology & atmospheric sciences, rugose lagoon, Science, Multispectral image, 0211 other engineering and technologies, 02 engineering and technology, UNESCO World Heritage Area, 01 natural sciences, Range (statistics), adaptive iterative model, Bathymetry, 14. Life underwater, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Block (data storage), geography, geography.geographical_feature_category, Single band, Coral reef, satellite derived bathymetry, band ratio, multispectral image, Waves and shallow water, General Earth and Planetary Sciences, Band ratio, Geology
Abstract

To achieve high accuracy bathymetry retrieval using remote sensing images with robust performance in a 0 to 25 m-deep lagoon with sharp bottom depth variations, a new Iterative Multiple Band Ratio (IMBR) algorithm is tested against known Multiple Band Ratio (MBR) and Single Band Ratio (SBR) algorithms. The test was conducted using the five multispectral bands, at 10 to 60 m resolution, of a Sentinel-2 image of the 25 km2 Poe lagoon, a UNESCO World Heritage Area. The IMBR approach requires training datasets for the definitions of depth threshold at which optimal band ratios vary. IMBR achieved accuracy, quantified with an original block cross-validation procedure across the entire depth range reached a mean absolute error of 46.0 cm. It compares very favorably against MBR (78.3 cm) and the various SBR results (188–254 cm). The method is suitable for generalization to other sites pending a minimal ground-truth dataset crossing all the depth range being available. We stress that different users may need different precisions and can use MBR or SBR algorithms for their applications. For the hydrodynamic modelling applications that are developing in New Caledonia, the IMBR solutions applied to Sentinel imagery are optimal.

Published
2021
Full Text
View/download PDF

2. Understanding connectivity of pearl oyster populations within Tuamotu atoll semi-closed lagoons: Cumulative insight from genetics and biophysical modelling approaches

Author

Céline M. O. Reisser, Romain Le Gendre, Serge Andréfouët, Alain Lo-Yat, Yoann Thomas, Institut de Recherche pour le Développement (IRD), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and ANR-16-CE32-0004,MANA,Gestion des Atolls(2016)

Subjects
0106 biological sciences, Connectivity matrix, Biogeography, Population, Population Dynamics, Atoll, Aquaculture, 010501 environmental sciences, Aquatic Science, engineering.material, Oceanography, 01 natural sciences, Pinctada margaritifera, Population genomics, Dispersal modelling, Animals, 14. Life underwater, Pinctada, education, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Genetics, geography, education.field_of_study, geography.geographical_feature_category, Pacific Ocean, biology, 010604 marine biology & hydrobiology, Sampling (statistics), Agriculture, biology.organism_classification, Pollution, Lagoon hydrodynamics, engineering, Biological dispersal, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Pearl
Abstract

Connectivity affects species demography, (meta)population dynamics, evolution, phylogeny and biogeography. Various methodological approaches are applied to measure connectivity. Biophysical modelling can explore systematically the influence of atmospheric, oceanic and ecological forcing, while genetics measures connectivity patterns within the sampling strategy limit. In the Pacific Ocean pearl farming lagoons, the activity relies on spat collecting of the black lipped pearl oyster Pinctada margaritifera occurring after the larval dispersal phase, which follows spawning from wild or farmed populations. Biophysical 3D modelling and genomic studies have both separately brought insights on within-lagoon connectivity and on the origin of spats. Here, we combined previous genetics results with new realistic biophysical modelling scenarios to elucidate connectivity in Ahe Atoll lagoon. When combined, we identified the weather sequence likely explaining the realized connectivity observations. We discuss the strengths, weaknesses, opportunities and threats of combining these two approaches considering specific pearl farming demographic connectivity questions.

Published
2021
Full Text
View/download PDF

3. Hindcast and Near Real-Time Monitoring of Green Macroalgae Blooms in Shallow Coral Reef Lagoons Using Sentinel-2: A New-Caledonia Case Study

Author

Romain Le Gendre, Maële Brisset, Emmanuel Coutures, Claude Payri, Emmanuel Bourassin, Simon Van Wynsberge, Serge Andréfouët, and Benoit Soulard

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Science, satellite, algal bloom, 01 natural sciences, Algal bloom, Ulva, remote sensing, Hindcast, 14. Life underwater, Seabed, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Pacific lagoons, 010604 marine biology & hydrobiology, Coral reef, Spectral bands, Reflectivity, Oceanography, Sentinel-2, coral reefs, Temporal resolution, General Earth and Planetary Sciences, Environmental science, Satellite
Abstract

Despite the necessary trade-offs between spatial and temporal resolution, remote sensing is an effective approach to monitor macroalgae blooms, understand their origins and anticipate their developments. Monitoring of small tropical lagoons is challenging because they require high resolutions. Since 2017, the Sentinel-2 satellites has provided new perspectives, and the feasibility of monitoring green algae blooms was investigated in this study. In the Poé-Gouaro-Déva lagoon, New Caledonia, recent Ulva blooms are the cause of significant nuisances when beaching. Spectral indices using the blue and green spectral bands were confronted with field observations of algal abundances using images concurrent with fieldwork. Depending on seabed compositions and types of correction applied to reflectance data, the spectral indices explained between 1 and 64.9% of variance. The models providing the best statistical fit were used to revisit the algal dynamics using Sentinel-2 data from January 2017 to December 2019, through two image segmentation approaches: unsupervised and supervised. The latter accurately reproduced the two algal blooms that occurred in the area in 2018. This paper demonstrates that Sentinel-2 data can be an effective source to hindcast and monitor the dynamics of green algae in shallow lagoons.

Published
2021
Full Text
View/download PDF

4. Population Connectivity and Genetic Assessment of Exploited and Natural Populations of Pearl Oysters within a French Polynesian Atoll Lagoon

Author

Serge Andréfouët, Cassandre Chupeau, Romain Le Gendre, Alain Lo-Yat, Serge Planes, Céline M. O. Reisser, Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC), Centre de recherches insulaires et observatoire de l'environnement (CRIOBE), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), and ANR-16-CE32-0004,MANA,Gestion des Atolls(2016)

Subjects
0106 biological sciences, 0301 basic medicine, Population Dynamics, Atoll, Aquaculture, 01 natural sciences, Population genomics, Pinctada margaritifera, MARS3D, Genetics (clinical), education.field_of_study, geography.geographical_feature_category, Geography, biology, Agriculture, Biodiversity, pearl farming, connectivity, Seasons, Pearl, Conservation of Natural Resources, population genomics, lcsh:QH426-470, Population, engineering.material, Polynesia, Article, farming, Life history theory, 03 medical and health sciences, Genetics, Animals, Pinctada, 14. Life underwater, pearl, education, geography, [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE], business.industry, 010604 marine biology & hydrobiology, larval dispersal modelling, Correction, biology.organism_classification, Fishery, [SDV.GEN.GA]Life Sciences [q-bio]/Genetics/Animal genetics, lcsh:Genetics, Genetics, Population, 030104 developmental biology, Hydrodynamics, engineering, Biological dispersal, business
Abstract

International audience; In French Polynesia, the production and exportation of black pearls through the aquaculture of the black-lip pearl oyster Pinctada margaritifera provide the second largest economic income for the country after tourism. This industry entirely relies on the collection of natural spats from few highly recruiting lagoons. In recent years, pearl oyster producers have experienced variable success rates in spat collection, with significant spatial and temporal variability in spat supply, driving uncertainty in the future of pearl production. This study combines, for the first time in a farmed lagoon, genetic (SNPs), demographic (sex ratio, age), and biophysical data (larval dispersal modelling) to shed new light on population dynamics, connectivity, and spat recruitment in Ahe Atoll, a well-studied pearl farming site. Our results indicate that the geographical structuring of the natural populations and the contribution of both natural and exploited stocks to the production of spats result from the interaction of hydrodynamic features, life history traits and demographic parameters: the northeastern natural populations are older, not well connected to the southwestern natural populations and are not replenished by larvae produced by adjacent exploited populations. Moreover, we observe that the exploited populations did not contribute to larval production during our experiment, despite a sampling period set during the most productive season for spat collection. This is likely the result of a strong male bias in the exploited populations, coupled with a sweepstakes reproductive strategy of the species. Our results warrant further investigations over the future of the northeastern older natural populations and a reflection on the current perliculture techniques

Published
2020
Full Text
View/download PDF

5. Surveying shrimp aquaculture pond activity using multitemporal VHSR satellite images - case study from the Perancak estuary, Bali, Indonesia

Author

Benoit Soulard, Christophe Proisy, Niken Financia Gusmawati, Hugues Lemonnier, Romain Le Gendre, Nazha Selmaoui-Folcher, Thierry Laugier, Akhmad Mustafa, Agency of Research and Development for Marine and Fisheries, Ministry of Marine Affairs and Fisheries, Pôle Pluridisciplinaire de la Matière et de l'Environnement (PPME), Université de la Nouvelle-Calédonie (UNC), IFREMER LEAD-NC, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut Français de Pondichéry (IFP), Ministère de l'Europe et des Affaires étrangères (MEAE)-Centre National de la Recherche Scientifique (CNRS), Université de la Nouvelle Calédonie (UNC), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Centre National de la Recherche Scientifique (CNRS)-Ministère de l'Europe et des Affaires étrangères (MEAE)

Subjects
0106 biological sciences, Shrimp aquaculture, 010504 meteorology & atmospheric sciences, Climate, [SDV]Life Sciences [q-bio], Aquaculture, Image haute résolution, Aquatic Science, Oceanography, 01 natural sciences, Spatial and temporal survey, Decapoda, Abandoned ponds, Animals, VHSR images, 14. Life underwater, Ponds, Ecosystem, 0105 earth and related environmental sciences, geography, Production area, geography.geographical_feature_category, business.industry, 010604 marine biology & hydrobiology, Environmental engineering, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Estuary, Vegetation, 15. Life on land, Ecosystem assessment, Pollution, 6. Clean water, Shrimp, Fishery, Indicator, Indonesia, 13. Climate action, Supervised classification, Environmental science, Satellite, Estuaries, business
Abstract

International audience; From the 1980's, Indonesian shrimp production has continuously increased through a large expansion of culturedareas and an intensification of the production. As consequences of diseases and environmental degradations linkedto this development, there are currently 250,000 ha of abandoned ponds in Indonesia. To implement effectiveprocedure to undertake appropriate aquaculture ecosystem assessment and monitoring, an integrated indicatorbased on four criteria using very high spatial optical satellite images, has been developed to discriminate activefrom abandoned ponds. These criteria were: presence of water, aerator, feeding bridge and vegetation. Thisindicator has then been applied to the Perancak estuary, a production area in decline, to highlight the abandonmentdynamic between 2001 and 2015. Two risk factors that could contribute to explain dynamics of abandonmentwereidentified: climate conditions and pond locations within the estuary, suggesting that a spatial approach should beintegrated in planning processes to operationalize pond rehabilitation.

Published
2018
Full Text
View/download PDF

6. Carbon Dynamics Along the Seine River Network: Insight From a Coupled Estuarine/River Modeling Approach

Author

Goulven G. Laruelle, Audrey Marescaux, Romain Le Gendre, Josette Garnier, Christophe Rabouille, Vincent Thieu, Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lagons, Ecosystèmes et Aquaculture Durable [Nouméa] (LEAD), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Fédération Île-de-France de Recherche sur l'Environnement (FIRE ), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École pratique des hautes études (EPHE)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Fédération Île-de-France de Recherche sur l'Environnement (FIRE (FR_3020)), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Lagons, Ecosystèmes et Aquaculture Durable de Nouvelle Calédonie (LEADNC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université libre de Bruxelles (ULB), and Sorbonne Université (SU)

Subjects
0106 biological sciences, Watershed, lcsh:QH1-199.5, 010504 meteorology & atmospheric sciences, Seine river and estuary, Alkalinity, chemistry.chemical_element, Ocean Engineering, lcsh:General. Including nature conservation, geographical distribution, Aquatic Science, Oceanography, 01 natural sciences, chemistry.chemical_compound, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Dissolved organic carbon, lcsh:Science, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Total organic carbon, Hydrology, Global and Planetary Change, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, dissolved inorganic and organic carbon, carbon dioxide, Estuary, 6. Clean water, reactive-transport model, chemistry, 13. Climate action, [SDE]Environmental Sciences, biogeochemical budget, Carbon dioxide, Carbonate, Environmental science, lcsh:Q, Carbon, Sciences exactes et naturelles
Abstract

International audience; The Seine river discharges over 700 Gg of carbon (C) every year into the sea mostly under the form of dissolved inorganic carbon (DIC) and emits 445 Gg under the form of carbon dioxide (CO2) to the atmosphere over its entire river network. The watershed, which drains 76,000 km2, is heavily populated with 18 106 inhabitants and is thus submitted to large anthropic pressure. The offline coupling of two Reactive Transport Models is used to understand the complex spatial and temporal dynamics of carbon, oxygen and nutrients and quantify the CO2 exchange at the air-water interface along the main axis of the river. The estuarine section of the Seine is simulated by the generic estuarine model C-GEM (for Carbon Generic Estuarine Model), while the upstream part of the network, devoid of tidal influence is simulated by the pyNuts-Riverstrahler modeling platform which also includes an explicit representation of the drainage network ecological functioning. Our simulations provide a process-based representation of nutrients, oxygen, total organic carbon (TOC) and the carbonate system (DIC and alkalinity) over the entire year 2010. Our coupled modeling chain allows quantifying the respective contributions of the estuarine and freshwater sections of the system in the removal of carbon as well as following the fate of TOC and DIC along the river network. Our results also allow calculating an integrated carbon budget of the Seine river network for year 2010.

Published
2019
Full Text
View/download PDF

7. Monitoring pearl farming lagoon temperature with global high resolution satellite-derived products: An evaluation using Raroia Atoll, French Polynesia

Author

Serge Andréfouët, Simon Van Wynsberge, Nathanaël Sangare, Jérôme Aucan, Vetea Liao, Romain Le Gendre, and Christophe E. Menkès

Subjects
0106 biological sciences, Sea surface temperature, Dynamic, Satellite SST, Atoll, Context (language use), Aquaculture, 010501 environmental sciences, Aquatic Science, engineering.material, Oceanography, 01 natural sciences, Polynesia, Pinctada margaritifera, Animals, Pinctada, 14. Life underwater, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, biology, MUR SST, Energy Budget, 010604 marine biology & hydrobiology, Temperature, Agriculture, Pelagic zone, biology.organism_classification, Pollution, G1SST, 13. Climate action, Archipelago, engineering, Environmental science, Satellite, Dynamic Energy Budget, Pearl
Abstract

Temperature is important for pearl oyster reproduction, pelagic larval duration, and growth in the context of pearl farming, but has seldom been monitored over long periods in remote atolls. To test if satellite-derived Sea Surface Temperature (SST) could provide a solution, two daily global SST products were compared with 18 high precision loggers deployed during 10-months in the wide Raroia atoll (Tuamotu Archipelago, French Polynesia). The Multi-scale-Ultra-high-Resolution (MUR) SST was better correlated with lagoon temperature (r > 0.97) than the Global-Foundation-Sea-Surface-Temperature-Analysis (G1SST) SST (r < 0.94). Differences between observations and MUR SST ranged between -0.75 degrees C and + 1.12 degrees C and were influenced by seasons and locations, depth, and hours of measurements. Within this uncertainty range, simulations using a Dynamic Energy Budget model predicted similar life traits of oysters. Therefore, MUR SST appears suitable to monitor lagoon temperature in wide atolls, model oyster population dynamics and assist pearl oyster research and management.

Published
2020
Full Text
View/download PDF

8. Impact of environmental variability on Pinctada margaritifera life-history traits: A full life cycle deb modeling approach

Author

Alain Lo-Yat, Gilles Le Moullac, Nathanaël Sangare, Serge Andréfouët, Romain Le Gendre, Benoit Beliaeff, Yoann Thomas, Sébastien Lefebvre, Laure Pecquerie, Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Lagons, Ecosystèmes et Aquaculture Durable de Nouvelle Calédonie (LEADNC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), This study was co-funded by the Institut français de recherche pour l'exploitation de la mer (IFREMER) and the Direction des Ressources Marines et Minières de Polynésie française (DRMM). Support was also provided through the ANR-16-CE32-0004 MANA (Management of Atolls) project, ANR-16-CE32-0004,MANA,Gestion des Atolls(2016), Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Lagons, Ecosystèmes et Aquaculture Durable [Nouméa] (LEAD), and Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD)

Subjects
0106 biological sciences, Environmental change, Physiology, Dynamic energy budget, Population, Bioenergetics, 010603 evolutionary biology, 01 natural sciences, Life history theory, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, medicine, 14. Life underwater, education, Trophic level, Dynamic energy budget theory, education.field_of_study, biology, Ecology, Acl, 010604 marine biology & hydrobiology, Ecological Modeling, Bivalve, Pinctada margaritifera, Pearl farming, Seasonality, biology.organism_classification, medicine.disease, Sustainable management, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

International audience; The black-lipped pearl oyster (Pinctada margaritifera) is extensively farmed in French Polynesia to produce black pearls. For a sustainable management of marine resources, studying interactions between organisms and environment, and the associated factors and processes that will impact their life cycle and thus modulate population dynamics is a major research priority. Here, we describe black-lipped pearl oyster energy acquisition and use, and its control by temperature and food concentration within the Dynamic Energy Budget (DEB) theory framework. The model parametrization was based on literature data and a specific laboratory experiment. Model validation was carried out thanks to historical in-situ datasets and a dedicated field survey. Three theoretical environmental scenarios were built to investigate the response of the pearl oyster to environmental variations. We successfully modeled a wide range of life-stage-specific traits and processes, especially the delayed acceleration of growth after settlement. Applying the model on field data collected at three different culture sites required only one free-fitted parameter, the half saturation coefficient Xk, which controls how ingestion depends on food density. Xk integrates all variations linked to the trophic environment. Analysis of the kinetics of energy fluxes under theoretical environmental scenarios suggests that temperature variations induce seasonality of reproduction in a species thought to spawn opportunistically throughout the whole year. The major influence of food concentration fluctuations on growth rate and reproductive effort is highlighted. The model showed the lower performances associated with recovery time between food-rich and starvation periods. The implications of these findings in the context of black pearl farming in a changing environment are discussed.

Published
2020
Full Text
View/download PDF

9. Managing the Agri-Food System of Watersheds to Combat Coastal Eutrophication: A Land-to-Sea Modelling Approach to the French Coastal English Channel

Author

Romain Le Gendre, Gilles Billen, Sylvain Théry, Philippe Riou, Vincent Thieu, Josette Garnier, Mathilde Schapira, Antsiva Ramarson, Alain Menesguen, Philippe Cugier, Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ODE/LITTORAL/LERN, laboratoire d'Ecologie Benthique (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Fédération Île-de-France de Recherche sur l'Environnement (FIRE ), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lagons, Ecosystèmes et Aquaculture Durable de Nouvelle Calédonie (LEADNC), Laboratoire d'Ecologie Benthique Côtière (LEBCO), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Environnement Ressources Morbihan Pays de Loire (LERMPL), LITTORAL (LITTORAL), École Pratique des Hautes Études (EPHE), Ifremer - Nouvelle-Calédonie, Fédération Île-de-France de Recherche sur l'Environnement (FIRE), and Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-AgroParisTech-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
0106 biological sciences, Pseudo-nitzschia spp, Fishing, Drainage basin, 010501 environmental sciences, Riparian wetlands, 01 natural sciences, Algal bloom, modelling, Ecosystem, 14. Life underwater, Greenhouse gas indirect emissions, river basins, 0105 earth and related environmental sciences, Seine river, 2. Zero hunger, nutrient flows, geography, geography.geographical_feature_category, business.industry, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, scenarios, Loir river, 15. Life on land, Crop rotation, 6. Clean water, pseudo-nitzschia spp, lcsh:Geology, 13. Climate action, Agriculture, [SDE]Environmental Sciences, Denitrification, General Earth and Planetary Sciences, Food systems, Environmental science, coastal zone ecosystem, toxic microalgae, Water resource management, business, Eutrophication
Abstract

International audience; The continental coastal waters of the Eastern Channel, from Normandy to Hauts-de-France, are subject to the major influence of unbalanced nutrient inputs from inflowing rivers. Several episodes of harmful algal blooms (HABs) compromising fishing and shellfish farming activities have been observed at the coast. For a better understanding of how the land-to-sea aquatic continuum functions, the GRAFS-RIVERSTRAHLER river biogeochemical model was implemented to cover the watersheds of 11 rivers flowing into this area (including the Seine) and chained with the ecological marine ECO-MARS3D model, applied to the French Northern coastal zone. Human activities strongly impact on the functioning of coastal ecosystems. Specifically, for these fertile soils of Northern France, intensive agricultural nitrogen (N) deliveries in excess over silica (Si) and phosphorus (P), essentially of diffuse origin, are potentially responsible for coastal eutrophication. Phosphorous is today equally supplied by diffuse and point sources, after a drastic reduction of inputs from wastewater treatment plants since the 2000s, and is better balanced regarding Si, as shown by the indicators of coastal eutrophication potential (P-ICEP versus N-ICEP). However, despite this drastic P reduction, HABs still appear repeatedly. Exploration of several scenarios of agro-food chain reorganization shows that (i) further progress in urban wastewater treatment to fully comply with current European regulations will not result in a significant reduction of nutrient fluxes to the sea, hence including HABs, and (ii) radical structural changes in agriculture, based on generalization of long and diversified organic crop rotations, reconnection of crop and livestock farming and changes in the human diet have the capacity to significantly reduce nutrient flows, coastal eutrophication and HABs.

Published
2019
Full Text
View/download PDF

10. Two decades of Pseudo-nitzschia spp. blooms and king scallop (Pecten maximus) contamination by domoic acid along the French Atlantic and English Channel coasts: Seasonal dynamics, spatial heterogeneity and interannual variability

Author

Romain Le Gendre, Bérengère Husson, Annie Chapelle, Mathilde Schapira, and Tania Hernández-Fariñas

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Plant Science, Aquatic Science, Biology, 01 natural sciences, Domoic acid, Interannual variability, Phytoplankton, Environmental parameters, Pecten maximus, 14. Life underwater, King scallop, 0105 earth and related environmental sciences, 010604 marine biology & hydrobiology, Pseudo-nitzschia spp, Plankton, biology.organism_classification, Seasonal dynamics, Fishery, Oceanography, Diatom, 13. Climate action, Scallop, Bloom, Pseudo-nitzschia, Bay
Abstract

King scallop contamination (Pecten maximus) by domoic acid, a neurotoxin produced by some species of the diatom Pseudo-nitzschia, is highly problematic because of its lengthy retention in the bivalve tissue, leading to prolonged fishery closures. Data collected within the French Phytoplankton and Phycotoxin monitoring network (REPHY) over the 1995–2012 period were used to characterize the seasonal dynamics and the interannual variability of P.-nitzschia spp. blooms as well as the contamination of king scallop fishing grounds, in six contrasted bays distributed along the French Atlantic coast and English Channel. Monitoring revealed that these toxic events have become more frequent since the year 2000, but with varying magnitudes, frequencies and timing depending on the bay. Two bays, located in southern Brittany, exhibited both recurrent contaminations and high P.-nitzschia abundances. The Brest bay and the Seine bay were intermittently affected. The Pertuis Breton exhibited only one major toxic event related to an exceptionally intense bloom of P.-nitzschia in 2010, and the Saint Brieuc bay neither showed significant contamination nor high P.-nitzschia abundance. While high P.-nitzschia abundance appeared to be correlated to scallop toxicity, this study highlights the difficulty in linking P.-nitzschia spp. blooms to king scallop contamination through monitoring. Indeed, P.-nitzschia was determined at the genus level and data regarding species abundances and their toxicity levels are an absolute prerequisite to further assess the environmental control of ASP events. As results describe distinct P.-nitzschia bloom dynamics along the French coast, this may suggest distinct controlling factors. They also revealed that major climatic events, such as the winter storm Xynthia in 2010, can trigger toxicity in P.-nitzschia over a large spatial scale and impact king scallop fisheries all along the coast.

Published
2016
Full Text
View/download PDF

11. Are Sea Surface Temperature satellite measurements reliable proxies of lagoon temperature in the South Pacific?

Author

Teuru Passfield, Serge Andréfouët, Simon Van Wynsberge, Romain Le Gendre, Christophe E. Menkès, Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), Processus de couplage à Petite Echelle, Ecosystèmes et Prédateurs Supérieurs (PEPS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Lagons, Ecosystèmes et Aquaculture Durable de Nouvelle Calédonie (LEADNC), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Ministry of Marine Resources, GOPS (www.observatoire-gops.org) and by the Direction des Ressources Marines et Minières in French Polynesia., ANR-16-CE32-0004,MANA,Gestion des Atolls(2016), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Unité de recherche Lagons, Ecosystèmes et Aquaculture Durable en Nouvelle Calédonie, Ifremer - Nouvelle-Calédonie, and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Université de la Nouvelle-Calédonie (UNC)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Coral bleaching, Atoll, Climate change, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Aquatic Science, Oceanography, 01 natural sciences, Pacific ocean, Sea Surface Temperature, 14. Life underwater, Reef, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Pacific islands, Reef aperture, Coral reef, Sea surface temperature, 13. Climate action, Climatology, Atoll lagoon, Linear correlation, Geology
Abstract

International audience; In remote coral reef environments, lagoon and reef in situ measurements of temperature are scarce. Sea Surface Temperature (SST) measured by satellite has been frequently used as a proxy of the lagoon temperature experienced by coral reef organisms (TL) especially during coral bleaching events. However, the link between SST and TL is poorly characterized. First, we compared the correlation between various SST series and TL from 2012 to 2016 in three atolls and one island in the Central South Pacific Ocean. Simple linear correlation between SST and TLranged between 0.44 and 0.97 depending on lagoons, localities of sensors, and type of SST data. High-resolution-satellite-measurements of SST inside the lagoons did not outperform oceanic SST series, suggesting that SST products are not adapted for small lagoons. Second, we modelled the difference between oceanic SST and TL as a function of the drivers of lagoon water renewal and mixing, namely waves, tide, wind, and season. The multivariate models reduced significantly the bias between oceanic SST and T. In atoll lagoons, and probably in other hydrodynamically semi-open systems, a correction taking into account these factors is necessary when SST are used to characterize organisms’ thermal stress thresholds.

Published
2017
Full Text
View/download PDF

12. Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France)

Author

Pauline Bazin, Bertrand Le Roy, Juliette Fauchot, Romain Le Gendre, Didier Goux, Philippe Riou, Pascal Claquin, Mathilde Schapira, Maxine Thorel, Anne-Flore Deton-Cabanillas, Virginie Raimbault, Valérie Kientz-Bouchart, Biologie des mollusques marins et des écosystèmes associés (BioMEA), Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), IFREMER LEAD-NC, Laboratoire Environnement et Ressources de Normandie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Interactions Cellules Organismes Environnement (ICORE), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-CHU Caen, Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Tumorothèque de Caen Basse-Normandie (TCBN), Chirurgie digestive et hépatobiliaire, Centre Hospitalier Universitaire Estaing, Institut Pascal - Clermont Auvergne (IP), Sigma CLERMONT (Sigma CLERMONT)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Centre de Microscopie Appliquée à la Biologie [Caen] (CMABio3), Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Tumorothèque de Caen Basse-Normandie (TCBN)-Université de Caen Normandie (UNICAEN), LABÉO, Pôle d’analyses et de recherche de Normandie (LABÉO), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), ODE/LITTORAL/LERN, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), CHU Estaing [Clermont-Ferrand], Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 - Faculté des sciences pharmaceutiques et biologiques (UR1 Pharmacie), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Normandie Université (NU), and Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Time Factors, 010504 meteorology & atmospheric sciences, Plant Science, 01 natural sciences, chemistry.chemical_compound, Nutrient, English channel, ComputingMilieux_MISCELLANEOUS, Species diversity, education.field_of_study, Principal Component Analysis, Kainic Acid, Geography, Ecology, Domoic acid, Biodiversity, Bloom dynamics, Spring bloom, Bays, Environmental chemistry, [SDE]Environmental Sciences, France, Seasons, Bloom, [SDE.MCG]Environmental Sciences/Global Changes, Population, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aquatic Science, Biology, Phosphates, Species Specificity, 14. Life underwater, education, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, Diatoms, Nitrates, 010604 marine biology & hydrobiology, biology.organism_classification, Nutrient ratios, chemistry, Phytoplankton, Pseudo-nitzschia, Particulate Matter, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract

International audience; The population dynamics of different Pseudo-nitzschia species, along with particulate domoic acid (pDA) concentrations, were studied from May 2012 to December 2013 in the Bay of Seine (English Channel, Normandy). While Pseudo-nitzschia spp. blooms occurred during the two years of study, Pseudo-nitzschia species diversity and particulate domoic acid concentrations varied greatly. In 2012, three different species were identified during the spring bloom (P. australis, P. pungens and P. fraudulenta) with high pDA concentrations (similar to 1400 ngl(-1)) resulting in shellfish harvesting closures. In contrast, the 2013 spring was characterised by a P. delicatissima bloom without any toxic event. Above all, the results show that high pDA concentrations coincided with the presence of P. australis and with potential silicate limitation (Si: N < 1), while nitrate concentrations were still replete. The contrasting environmental conditions between 2012 and 2013 highlight different environmental controls that might favour the development of either P. delicatissima or P. australis. This study points to the key role of Pseudo-nitzschia diversity and cellular toxicity in the control of particulate domoic acid variations and highlights the fact that diversity and toxicity are influenced by nutrients, especially nutrient ratios. (C) 2017 Elsevier B.V. All rights reserved.

Published
2017
Full Text
View/download PDF

13. Long-term water quality in the lower Seine: Lessons learned over 4 decades of monitoring

Author

Marie Silvestre, Estela Romero, Gilles Billen, Philippe Riou, Romain Le Gendre, Josette Garnier, Cédric Fisson, Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Lagons, Ecosystèmes et Aquaculture Durable en Nouvelle Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Groupement d’Intérêt Public Seine-Aval (GIP-Seine-Aval), Pôle Régional des Savoirs, Fédération Île-de-France de Recherche sur l'Environnement (FIRE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement et Ressources de Normandie, Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Lagons, Ecosystèmes et Aquaculture Durable de Nouvelle Calédonie (LEADNC), Laboratoire Environnement Ressources de Normandie (LERN), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-AgroParisTech

Subjects
Pollution, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Geography, Planning and Development, Drainage basin, WFD, 010501 environmental sciences, Management, Monitoring, Policy and Law, 01 natural sciences, water quality, nutrients, 14. Life underwater, Environmental quality, 0105 earth and related environmental sciences, media_common, Seine River, Hydrology, geography, geography.geographical_feature_category, business.industry, Estuary, Nutrients, Long-term trends, Anoxic waters, 6. Clean water, Water quality, Policy, Water Framework Directive, 13. Climate action, Agriculture, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Water resource management, business, long - ­‐term trends, policy
Abstract

International audience; The Seine River is a highly artificialised catchment in Europe, comprising both productive agricultural areas and intense industrial and commercial activity. Due to its strategic importance, monitoring programs in the river started as early as the 1970s. The present study compiles and analyses this valuable data set (1970–2014), thoroughly describing the riverine section downstream of Paris and the estuary. We identify long-term trends and shifting patterns in nutrients and oxygen, and pay special attention to the river’s evolution after the year 2000, when the European Water Framework Directive came into force. The study has a manifest management perspective, and the results are discussed on the basis of the environmental quality standards proposed in current environmental regulations. The data show that water quality has improved remarkably over the past two decades, with sharp reductions of ammonium and phosphate and a progressive increase of dissolved oxygen levels. The amelioration is prominent in the estuary, where summer anoxic episodes have nearly disappeared. As a result, these three parameters are nowadays in good or very good condition throughout the year. The successful abatement of point sources contrasts, however, with the low effectiveness of the measures provided for the control of nutrients from diffuse sources. Nitrate concentration has increased by 150% since the early 1980s, and only very recently has the upward trend been reversed. Bold agri-environmental management measures are required if we are to prevent chronic pollution problems and truly restore the good ecological status of rivers.

Published
2016
Full Text
View/download PDF

14. Eutrophication modelling chain for improved management strategies to prevent algal blooms in the Bay of Seine

Author

Francois Paris, Josette Garnier, Philippe Riou, Paul Passy, Philippe Cugier, Gilles Billen, Estella Romero, Romain Le Gendre, Julie Callens, Department of Geography, National University of Singapore (NUS), Fédération Île-de-France de Recherche sur l'Environnement (FIRE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement Ressources de Normandie (LERN), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Université Pierre et Marie Curie - Paris 6 (UPMC), Dynamiques de l'Environnement Côtier (DYNECO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Laboratoire d'Ecologie Benthique Côtière (LEBCO), and Dynamiques des Écosystèmes Côtiers (DYNECO)

Subjects
010504 meteorology & atmospheric sciences, 010501 environmental sciences, Aquatic Science, 01 natural sciences, Algal bloom, Modelling, Harmful algal blooms, Nutrient load, Ecosystem, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Ecology, Primary producers, biology, Estuary, Seine, Plankton, Eutrophication, biology.organism_classification, 6. Clean water, Fishery, Water quality, 13. Climate action, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, Dinophysis
Abstract

International audience; Eutrophication of the Seine estuary and the Bay of Seine is a crucial environmental issue for the management of ecosystems and economic activities related to fisheries and tourism in the region. A large quantity of nutrients, especially nitrogen, is brought to the coastal zone by the Seine River, the main input into that area, but also by smaller rivers along the Normandy coast. This large delivery of nitrogen leads to an imbalance between nitrogen (N), phosphorus (P) and silica (Si), which affects the growth of planktonic organisms and can exacerbate the occurrence of harmful algal blooms (HABs). These events can be damaging for shellfish fisheries, an important economic resource for the region. The study describes a new modelling chain coupling a riverine and a marine model (the Seneque/Riverstrahler and the ECO-MARS3D, respectively), which allows us to explore the effects on the coast of 2 scenarios of watershed management. The first one, focused on an upgrade of wastewater treatment plants, decreases the P fluxes by 5 to 35 kg P km–2 yr–1 on average over the 2000 to 2006 period, depending on the watershed, and would reduce about 3-fold the concentration of dinoflagellates in the adjacent coastal zone. The second one explores a hypothetical scenario of generalisation of organic farming in all agricultural areas of the basin. Although this is not realistic, it shows the best theoretical results we can achieve. With this scenario, the N fluxes decrease by almost 50%, and the dinoflagellate blooms and thus possibly the Dinophysis spp. blooms are drastically reduced by a factor of 20 to 40. Nevertheless, diatoms, which are the main primary producers in the bay and sustain the marine food web, are not significantly affected by this drastic scenario.

Published
2016
Full Text
View/download PDF

15. Towards the determination of Mytilus edulis food preferences using the dynamic energy budget (DEB) theory

Author

Coralie Picoche, Frank Maheux, Benjamin Simon, Jonathan Flye-Sainte-Marie, Aline Gangnery, Sylvaine Francoise, Romain Le Gendre, Laboratoire Environnement Ressources de Normandie (LERN), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Wollongong [Australia], LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, food intake, Mytilus edulis, [SDV]Life Sciences [q-bio], Marine and Aquatic Sciences, lcsh:Medicine, Aquaculture, life history trait, 01 natural sciences, environmental factor, Biomass, lcsh:Science, Animal Management, Multidisciplinary, Ecology, Geography, plankton, species habitat, Agriculture, Plankton, particle size, Mytilus, Trophic Interactions, Community Ecology, Habitat, Calibration, Phycology, water immersion, growth rate, France, Coastal Ecology, Blue mussel, Research Article, nutrient dynamics, metabolic parameters, Animal Types, Dynamic energy budget, chlorophyll a, Marine Biology, Environment, Biology, food quality, Models, Biological, 010603 evolutionary biology, Article, animal tissue, social behavior, Food Preferences, water temperature, Marine Monitoring, Phytoplankton, Animals, controlled study, 14. Life underwater, nutritional value, energy transfer, nonhuman, 010604 marine biology & hydrobiology, organic carbon, ACL, Ecology and Environmental Sciences, fungi, lcsh:R, Biology and Life Sciences, Mussel, biology.organism_classification, Fishery, Earth Sciences, Veterinary Science, dynamic energy budget, lcsh:Q, food preference, Mariculture, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Energy Metabolism, Food quality, Aquatic Animals
Abstract

International audience; The blue mussel, Mytilus edulis, is a commercially important species, with production based on both fisheries and aquaculture. Dynamic Energy Budget (DEB) models have been extensively applied to study its energetics but such applications require a deep understanding of its nutrition, from filtration to assimilation. Being filter feeders, mussels show multiple responses to temporal fluctuations in their food and environment, raising questions that can be investigated by modeling. To provide a better insight into mussel-environment interactions, an experiment was conducted in one of the main French growing zones (Utah Beach, Normandy). Mussel growth was monitored monthly for 18 months, with a large number of environmental descriptors measured in parallel. Food proxies such as chlorophyll a, particulate organic carbon and phytoplankton were also sampled, in addition to non-nutritious particles. High-frequency physical data recording (e.g., water temperature, immersion duration) completed the habitat description. Measures revealed an increase in dry flesh mass during the first year, followed by a high mass loss, which could not be completely explained by the DEB model using raw external signals. We propose two methods that reconstruct food from shell length and dry flesh mass variations. The former depends on the inversion of the growth equation while the latter is based on iterative simulations. Assemblages of food proxies are then related to reconstructed food input, with a special focus on plankton species. A characteristic contribution is attributed to these sources to estimate nutritional values for mussels. M. edulis shows no preference between most plankton life history traits. Selection is based on the size of the ingested particles, which is modified by the volume and social behavior of plankton species. This finding reveals the importance of diet diversity and both passive and active selections, and confirms the need to adjust DEB models to different populations and sites.

Published
2014
Full Text
View/download PDF

16. Large-scale patterns of river inputs in southwestern Europe: seasonal and interannual variations and potential eutrophication effects at the coastal zone

Author

Estela Romero, Philippe Riou, Josette Garnier, Gilles Billen, Romain Le Gendre, Luis Lassaletta, Philippe Cugier, Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement Ressources de Normandie (LERN), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Ecologie Benthique Côtière (LEBCO), Dynamiques des Écosystèmes Côtiers (DYNECO), Federation Ile-de-France for Research on the Environment (FIRE FR3020 CNRS UPMC), European Science Foundation, Paris City Council (Research in Paris), French project NEREIS, FP7 European AWARE project, French project PASTEK (GIS-Climat), Agence de l'Eau Seine Normandie, Region Basse Normandie, Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Laboratoire Écologie Benthique (LEB)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Context (language use), Coastal zone, 01 natural sciences, Algal bloom, Nutrient, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Phytoplankton, medicine, Environmental Chemistry, Ecosystem, 14. Life underwater, P:Si stoichiometry [N], 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, 010604 marine biology & hydrobiology, N:P:Si stoichiometry, Seasonality, 15. Life on land, Eutrophication, medicine.disease, 6. Clean water, Europe, Oceanography, 13. Climate action, Environmental science, River inputs, Bay
Abstract

International audience; We provide data on nutrient export for 28 rivers in southwestern Europe and analyze long-term changes in the context of anthropogenic pressures and regulation policies. Special attention is given to seasonal variations, because the integrated annual values that are usually provided do not allow us to establish comparisons with seasonal phytoplankton dynamics. The eutrophication risk associated with river inputs is addressed by means of an indicator (Index of Coastal Eutrophication Potential, ICEP, Billen and Garnier, Mar Chem 106:148-160, 2007). An overview of the temporal evolution and the intra-annual variability of the ICEP is discussed for specific rivers and integrated coastal regions. The annual dynamics of the eutrophication indicator is analyzed to delimit those periods when the risk of eutrophication is particularly high. The trends in nutrient fluxes and coastal phytoplankton are compared by means of a case study (Seine Bay). The decrease in phosphorus matches a general decrease in phytoplankton biomass in the summer. However, sustained high values of nitrogen still foster the emergence of harmful algal blooms, and we found an increase in the summer abundance of dinoflagellates. The abatement of phosphorus alone is not enough to shortcut harmful blooms and toxic outbreaks in the Seine Bay. A reduction in nitrogen inputs may be necessary to effectively minimize eutrophication problems.

Published
2013
Full Text
View/download PDF

17. Spatial Variability of Benthic-Pelagic Coupling in an Estuary Ecosystem: Consequences for Microphytobenthos Resuspension Phenomenon

Author

Karine Grangeré, Martin Ubertini, Romain Le Gendre, Aline Gangnery, Sébastien Lefebvre, Francis Orvain, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord])

Subjects
0106 biological sciences, Geologic Sediments, Time Factors, 010504 meteorology & atmospheric sciences, Marine and Aquatic Sciences, lcsh:Medicine, Oceanography, 01 natural sciences, Water column, Microalgae, Spatial and Landscape Ecology, Biomass, lcsh:Science, Trophic level, Biomass (ecology), Principal Component Analysis, Multidisciplinary, geography.geographical_feature_category, Geography, Ecology, Marine Ecology, Malacology, Biota, Benthic zone, Phycology, Seasons, Estuaries, Marine Geology, Coastal Ecology, Research Article, Marine Biology, Ecosystems, Animals, Ecosystem, 14. Life underwater, Biology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Spatial Analysis, 010604 marine biology & hydrobiology, Plant Ecology, lcsh:R, Reproducibility of Results, Pelagic zone, Estuary, 15. Life on land, 13. Climate action, Mollusca, Earth Sciences, lcsh:Q, Bay, Zoology, Environmental Sciences, Ecological Environments
Abstract

International audience; The high degree of physical factors in intertidal estuarine ecosystem increases material processing between benthic and pelagic compartments. In these ecosystems, microphytobenthos resuspension is a major phenomenon since its contribution to higher trophic levels can be highly significant. Understanding the sediment and associated microphytobenthos resuspension and its fate in the water column is indispensable for measuring the food available to benthic and pelagic food webs. To identify and hierarchize the physical/biological factors potentially involved in MPB resuspension, the entire intertidal area and surrounding water column of an estuarine ecosystem, the Bay des Veys, was sampled during ebb tide. A wide range of physical parameters (hydrodynamic regime, grain size of the sediment, and suspended matter) and biological parameters (flora and fauna assemblages, chlorophyll) were analyzed to characterize benthic-pelagic coupling at the bay scale. Samples were collected in two contrasted periods, spring and late summer, to assess the impact of forcing variables on benthic-pelagic coupling. A mapping approach using kriging interpolation enabled us to overlay benthic and pelagic maps of physical and biological variables, for both hydrological conditions and trophic indicators. Pelagic Chl a concentration was the best predictor explaining the suspension-feeders spatial distribution. Our results also suggest a perennial spatio-temporal structure of both benthic and pelagic compartments in the ecosystem, at least when the system is not imposed to intense wind, with MPB distribution controlled by both grain size and bathymetry. The benthic component appeared to control the pelagic one via resuspension phenomena at the scale of the bay. Co-inertia analysis showed closer benthic-pelagic coupling between the variables in spring. The higher MPB biomass observed in summer suggests a higher contribution to filter-feeders diets, indicating a higher resuspension effect in summer than in spring, in turn suggesting an important role of macrofauna bioturbation and filter feeding (Cerastoderma edule).

Published
2012
Full Text
View/download PDF

18. Island shadow effects and the wave climate of the western Tuamotu archipelago (French Polynesia) inferred from altimetry and numerical model data

Author

Serge Andréfouët, Fabrice Ardhuin, Romain Le Gendre, Pierre Queffeulou, Andréfouët, Serge (ed.), and Charpy, Loïc (ed.)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Climate, Atoll, Aquatic Science, Oceanography, 01 natural sciences, CLIMATOLOGIE, Polynesia, ALTIMETRIE, Wave model, LAGON, Shadow, Water Movements, Seawater, 14. Life underwater, Altimeter, Spacecraft, Weather, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Atmosphere, Altitude, 010604 marine biology & hydrobiology, IMPACT DE L'ENVIRONNEMENT, Storm, Models, Theoretical, Pollution, Swell, CIRCULATION OCEANIQUE, Climatology, Remote Sensing Technology, Archipelago, MODELE NUMERIQUE DE TERRAIN, Seasons, Significant wave height, Geology, Environmental Monitoring
Abstract

To implement a numerical model of atoll lagoon circulation, we characterized first the significant wave height (Hs) regime of the Western Tuamotu Archipelago and the local attenuation due to the protection offered by large atolls in the south Tuamotu. Altimetry satellite data and a WAVEWATCH III two-way nested wave model at 5 km resolution from 2000 to 2010 were used. Correlation between altimetry and model was high (0.88) over the period. According to the wave model, the archipelago inner seas experienced attenuated Hs year-long with a yearly average Hs around 1.3 m vs a minimum of 1.6 m elsewhere. The island shadow effect is especially significant in the austral winter. In contrast with southern atolls, Western Tuamotu experienced only few days per year of Hs larger than 2.5 m generated by very high Hs southern swell, transient western local storms, strong easterly winds, and during the passage of distant hurricanes.

Published
2012

19. Phytoplankton dynamics in the southern New Caledonian lagoon during a southeast trade winds event

Author

Sylvain Ouillon, Francis Gallois, Claude Courties, Philippe Gérard, Jean-Michel Fernandez, Romain Le Gendre, Jean-Pierre Lefebvre, Cécile Dupouy, Jacques Neveux, Laboratoire d'océanographie biologique de Banyuls (LOBB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Echanges Côte-Large (ECOLA), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Laboratoire Environnement Ressources de Normandie (LERN), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), LITTORAL (LITTORAL), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)

Subjects
0106 biological sciences, Chlorophyll, Chlorophyll a, 010504 meteorology & atmospheric sciences, Aquatic Science, Oceanography, 01 natural sciences, chemistry.chemical_compound, New Caledonia, Phytoplankton, 14. Life underwater, Flow cytometry, Diel vertical migration, Reef, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, geography, Trade winds, geography.geographical_feature_category, Growth rate, 010604 marine biology & hydrobiology, Phycoerythrin, Coral reef, Lagoon, Internal wave, In vivo fluorescence, chemistry, Thermocline, Surface water, Geology
Abstract

International audience; During the Echolag cruise (13 February-8 March 2007), the effect of 16-30 knot trade winds on abundance, community structure and dynamics of phytoplankton was investigated in the southern part of the New Caledonian coral reefs and surrounding oceanic waters. In this area, the coral reefs form two horn-like structures (hereinafter referred to as 'horn reefs'), oriented south-east, and separated by a relatively deep valley. Three repeated samplings at one week intervals of a 32 station array showed that trade winds induce surface water cooling and significant enrichment of mid- and bottom waters above the reef shelf. This enrichment appeared as the result of a general rise of the oceanic thermocline and nitracline due to the combination of trade winds and tidally-generated internal waves between the horn reefs. It was accompanied by a factor of 1.5 and 2.3 mean increase for the chlorophyll concentration and picoplankton-nanoplankton cell number, respectively. From diel variations of in vivo chlorophyll a fluorescence and hourly sampling, phytoplankton gross growth rate was estimated to be 1-1.35 divisions per day and was quasi balanced with phytoplankton mortality for a 24 h period.

Published
2010
Full Text
View/download PDF

20. A combined modelling and geochemical study of the fate of terrigenous inputs from mixed natural and mining sources in a coral reef lagoon (New Caledonia)

Author

Pascal Douillet, Jean-Michel Fernandez, C. Chevillon, Renaud Fichez, Sylvain Ouillon, Romain Le Gendre, UR Camelia, Institut de Recherche pour le Développement (IRD), Echanges Côte-Large (ECOLA), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement ( IRD ), ECOLA LEGOS, Laboratoire d'études en Géophysique et océanographie spatiales ( LEGOS ), and Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National d'Etudes Spatiales ( CNES ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National d'Etudes Spatiales ( CNES ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Geologic Sediments, 010504 meteorology & atmospheric sciences, Industrial Waste, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, Mining, New Caledonia, Metals, Heavy, Pelite, Animals, Seawater, 14. Life underwater, Open-cast mining, Sedimentology, Reef, Cr, 0105 earth and related environmental sciences, geochemistry, geography, Ni, geography.geographical_feature_category, Terrigenous sediment, open cast mining, sedimentology, Coral reef, 15. Life on land, Models, Theoretical, Anthozoa, Pollution, Geochemistry, hydrodynamics, Erosion, Hydrodynamics, Bay, Geology, Water Pollutants, Chemical, Environmental Monitoring
Abstract

Open-cast mining for Ni, Cr and Co was conducted in the south-west part of New Caledonia during the 20th century. Abandoned mining and prospecting sites were severely affected by erosion, resulting in all increase in the load of terrigenous particles transported to the coral reef lagoon. This article assesses the impact of a typical small catchment area (La Coulee River, 85 km 2 watershed) oil two bays (Boulari and Sainte Marie) located near Noumea, New Caledonia's main city. This multi-disciplinary study combines geochemical, sedimentological, and hydrodynamic approaches. Ni and Cr concentrations contained in the geochemical matrix phase of the pelitic fraction were determined. The study of the geochemical signatures together with sedimentological data and 3D numerical simulations of the transport of non-settling particles throughout the lagoon demonstrated that terrigenous inputs from the Coulee River were mainly transported and deposited along the shoreline, reaching areas as distant as Sainte Marie Bay. Although quantitatively low (about 3% of the pelite mass of the bay sediments), the terrigenous inputs in Sainte Marie Bay originating from the Coulee River could be traced. The metal content in Suspended matter was over 7000 mg kg(-1) for Ni and 4200 mg kg-1 for Cr. (c) 2005 Elsevier Ltd. All rights reserved.

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results