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19 results on '"Romain Le Gendre"'

2. Assessing the water quality of the Seine land-to-sea continuum for three agro-food system scenarios

Author

Estela Romero, Josette Garnier, Gilles Billen, Antsiva Ramarson, Philippe Riou, Romain Le Gendre, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), and Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Global and Planetary Change, eutrophication, [SDE]Environmental Sciences, scenarios, biogeochemical processes, Ocean Engineering, Aquatic Science, Oceanography, agro-food system, estuary, Water Science and Technology
Abstract

International audience; Three scenarios for the future of the French agro-food system were specified for the territory draining into the Seine Bight, comprising Paris megacity and the Seine watershed. The first scenario assumes the pursuit of the current trend of opening and specialization of agriculture, as well as of concentration of population within the Paris agglomeration. The second scenario assesses the generalization of agro-ecological practices and a healthier human diet. A third, hybrid, scenario was elaborated assuming that agro-ecological practices were implemented in some protected areas (namely Regional Natural Parks and drinking water protection areas, making up about one-third of the total watershed area), while the rest of the territory will follow the trends of the first scenario. We use a unique modelling chain (GRAFS-Riverstrahler-ECOMARS3D) that couples the biogeochemical functioning of the river basin, the estuary and the adjacent bay. It allows exploring the implications of changes in terrestrial activities throughout the aquatic continuum in a consistent way and assessing to what extent changes in population, agricultural practices, food consumption, and sanitation may sustain the current trend of recovery in the Seine River or either increase stress on the system. Results show that only the full agro-ecological scenario would be able to restore good water quality everywhere in the river network, as well as decrease significantly the risks of toxic algal blooms in the coastal zone. Intermediate situations, such as the protection of specific areas, however attractive as a solution, are not enough to offset the impacts of intensive human activities unless the protected areas dedicated to compensating for damage are sufficiently large.

Published
2022
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5. Natural stocks of Pinctada margaritifera pearl oysters in Tuamotu and Gambier lagoons: New assessments, temporal evolutions, and consequences for the French Polynesia pearl farming industry

Author

Océane Bionaz, Romain Le Gendre, Vetea Liao, and Serge Andréfouët

Subjects
Animals, Water, Agriculture, Aquaculture, Pinctada, Aquatic Science, Oceanography, Ostreidae, Pollution, Polynesia
Abstract

Knowledge of the status of the black-lipped pearl oyster Pinctada margaritifera populations is critical for the sustainability of the French Polynesia black pearl farming industry. Indeed, this activity relies on collection of spat settling out of the water column, which is inherently related to the abundance of in situ benthic stocks and their reproductive capacities. From surveys performed between 2016 and 2021, we present new stock assessments of natural wild oyster populations from four contrasted pearl farming lagoons (Gambier, Takapoto, Raroia, Takume). Also using Ahe atoll historical data, we first highlight how results vary with the methods (Direct, Zonal and Cokriging) used to scale in situ density measurements to lagoon-scale stocks. Takapoto and Gambier populations were also previously surveyed at least twice since the 1980s, allowing to demonstrate with field data clear changes in stock distributions and population structures. The consequences of our findings are discussed to provide recommendations for stock monitoring and management in the future.

Published
2022
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6. 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
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7. Tide and wave driven flow across the rim reef of the atoll of Raroia (Tuamotu, French Polynesia)

Author

Romain Le Gendre, Jérôme Aucan, Terence Desclaux, Serge Andréfouët, and Vetea Liao

Subjects
geography, geography.geographical_feature_category, Coral Reefs, Elevation, Atoll, Pelagic zone, Coral reef, Lagoon, Hydrodynamic, Aquatic Science, Pearl farming, Oceanography, Pollution, Polynesia, Water level, Current (stream), Physical Phenomena, Submarine pipeline, Reef, Geology
Abstract

The currents flowing across the rim of the atoll of Raroia were investigated with a 1 year-long dataset of wave, water level and currents. Offshore waves break on the edge of the reef outside the atoll's rim and drive current into the lagoon, through the shallow hoa that cut across the rim. The additional water volume generated by this wave driven flow induces an elevation of water level throughout the atoll's lagoon and is evacuated back into the open ocean through a deep reef pass. The water level inside the atoll is also driven by astronomical tides, which enter the lagoon thought the reef pass, after undergoing a ~50% decrease in amplitude and a ~4 hour lag. Using a simple parametric model with three calibrated coefficients, we show that currents across the atoll's rim can be estimated as a function of the offshore wave conditions and the water level difference between the ocean and the lagoon.

Published
2021

8. Seasonal changes in the photophysiology of Ulva batuffolosa in a coastal barrier reef

Author

Thierry Jauffrais, Maële Brisset, Laura Lagourgue, Claude E. Payri, Siloë Gobin, Romain Le Gendre, and Simon Van Wynsberge

Subjects
Chlorophyte, NPQ, Ulva batuffolosa, Rapid light curve, Pulse amplitude modulated fluorometer, Bloom, Coral reef, Plant Science, Aquatic Science
Abstract

To assess the photophysiological capacity of the recently described Ulva batuffolosa to form blooms in coral reefs, we monitored its biomass and photophysiological capacity with pulse amplitude modulated (PAM) fluorometry over a year period on a coastal barrier reef in New Caledonia, along with temperature and light. Effective and maximum quantum efficiencies of the photosystem II measured on this Ulva species indicated that the algae was in a “good health” all over the year with high quantum efficiencies under either light (Fq’/Fm’) or dark incubated conditions and (Fv/Fm). Photo-acclimation and -regulation status used by this Ulva sp. were driven by seasons (i.e., light and temperature) in the lagoon. Although photo-inhibition was an evidence during the warm period, U. batuffolosa was overall well adapted to tolerate the range of irradiance and temperature that characterized the lagoon over the year, which suggests that photosynthesis is not an impediment to green tides by this species.

Published
2022
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9. Periodicity of wave-driven flows and lagoon water renewal for 74 Central Pacific Ocean atolls

Author

Serge Andréfouët, Terence Desclaux, Julie Buttin, Swen Jullien, Jérôme Aucan, Romain Le Gendre, and Vetea Liao

Subjects
Pacific Ocean, Residence time, Water, Agriculture, Aquaculture, Pearl farming, Aquatic Science, Oceanography, Pollution, WaveWatch III, Polynesia, Tuamotu, Hoa, Animals, Wavelet transform, Pinctada
Abstract

French Polynesia atolls are spread on a vast 2300 by 1200 km Central Pacific Ocean area exposed to spatially and temporally dependent wave forcing. They also have a wide range of closed to open morphologies and several have been suitable to develop from black-lipped pearl oysters a substantial pearl farming activity in the past 30 years, representing nowadays the 2nd source of income for French Polynesia. Considering here only the component of lagoon renewal that is driven by waves, we investigate for 74 atolls different lagoon renewal metrics using 20 years of wave model data at 0.05° spatial resolution. Wavelet spectral analyses highlight that atolls, even in close vicinity, can be exposed to different and characteristic periodicities in wave-driven flows and water renewal. These characteristics are discussed in relation to pearl farming atolls, including atolls known to be efficient oyster spat producers, a critical activity for pearl farming sustainability.

Published
2022
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10. 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
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11. 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
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12. 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
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13. 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
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14. 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
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15. 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
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16. 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
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17. 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

18. 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
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19. 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
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