Consulta: creatorFacets:"Sourisseau, Marc"
Registros recuperados: 32
Data/hora: 01/06/2024 12:07:44

Diel changes in acoustic and catch estimates of krill biomass
Provedor de dados: 5
Autores: Simard, Yvan; Sourisseau, Marc.
Krill-biomass estimates can be compromised by diel variabilities in acoustic backscatter and the catch efficiencies of various nets. This paper describes an effort to quantify these variabilities at fine temporal and spatial scales during a three-day experiment at a fixed location, using high-resolution, stratified Bioness samples and echo-integration, and assuming a fixed distribution of krill orientations. Night-time catches in the krill scattering layer (SL) were 15 times the acoustic estimates. The situation was reversed during daytime, when the acoustic estimates in the SL were 5 times larger than the catches. This collectively resulted in a ±10-dB gradual diel cycle in the difference of vertically integrated biomass from both sampling methods. Use of...
Tipo: Text
Palavras-chave: Thysanoessa raschi; Target strength; Strobe light; St Lawrence Estuary; Meganyctiphanes norvegica; Krill; In situ orientation; Feeding; Diel vertical migration; Avoidance.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6591.pdf

Resource Competition Affects Plankton Community Structure; Evidence from Trait-Based Modeling
Provedor de dados: 5
Autores: Sourisseau, Marc; Le Guennec, Valerie; Le Gland, Guillaume; Plus, Martin; Chapelle, Annie.
Understanding the phenology of phytoplankton species is still a challenge and despite a lot of theoretical work on competition for ressources this process is under-represented in deterministic models. To study the main driver of the species selection, we thus used a trait-based model that keeps phenotypic variability through physiological trait parameterization. We next validate the results by using a key species, the toxic dinoflagellate Alexandrium minutum. Due to their monitoring, we show that harmful algae are ideal models for studying ecological niches and for contributing to this more global challenge. As a first step, a dimensionless model of an estuary (France) was built with water temperature and water exchanges deduced from a hydro-dynamic model....
Tipo: Text
Palavras-chave: Droop; Competition; Inter-specific; Estuary; Bay of Brest; Alexandrium minutum; Phenology; Niches.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00373/48414/48624.pdf

A 37 years hindcast of a coupled physical-biogeochemical model and its use for fisheries oceanography in the Bay of Biscay
Provedor de dados: 5
Autores: Huret, Martin; Petitgas, Pierre; Struski, Caroline; Leger, Fabien; Sourisseau, Marc; Lazure, Pascal.
Overexploitation and climate change are increasingly causing unanticipated changes in marine ecosystems, such as higher variability in fish recruitment and shifts in species distribution, pressing for developing fisheries oceanography. In the meantime, operational oceanography rapidly progresses and its products become easy to access to a large community, among them fisheries scientists. Multiyear oceanographic reanalyses (hindcasts) were identified has a priority product by the ICES WG on Operational Oceanographic Products for Fisheries and Environment (WGOOFE). We performed a 37 years hindcast (1972-2008) run with a coupled physical-biogeochemical model (ECO-MARS3D) over the Bay of Biscay, using realistic meteorological and run-off forcing. We first...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00023/13432/10442.pdf

Forecasting the risk of harmful algal blooms
Provedor de dados: 5
Autores: Davidson, Keith; Anderson, Donald M.; Mateus, Marcos; Reguera, Beatriz; Silke, Joe; Sourisseau, Marc; Maguire, Julie.
The “Applied Simulations and Integrated Modelling for the Understanding of Harmful Algal Blooms” (Asimuth) project sought to develop a harmful algal bloom (HAB) alert system for Atlantic Europe. This was approached by combining, at a national or regional level, regulatory monitoring phytoplankton and biotoxin data with satellite remote sensing and other information on current marine conditions, coupled with regional scale models that included a representation of HAB transport. Synthesis of these products was achieved by expert interpretation within HAB risk alert bulletins that were prepared on a regular basis (typically weekly) for use by the aquaculture industry. In this preface to the Asimuth Special Issue we outline the main HAB species of concern in...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00333/44435/45789.pdf

Biophysical Interactions Control the Size and Abundance of Large Phytoplankton Chains at the Ushant Tidal Front
Provedor de dados: 5
Autores: Landeira, Jose Maria; Ferron, Bruno; Lunven, Michel; Morin, Pascal; Marie, Louis; Sourisseau, Marc.
Phytoplankton blooms are usually dominated by chain-forming diatom species that can alter food pathways from primary producers to predators by reducing the interactions between intermediate trophic levels. The food-web modifications are determined by the length of the chains; however, the estimation is biased because traditional sampling strategies damage the chains and, therefore, change the phytoplankton size structure. Sedimentological studies around oceanic fronts have shown high concentrations of giant diatom mats (&gt;1 cm in length), suggesting that the size of diatom chains is underestimated in the pelagic realm. Here, we investigate the variability in size and abundance of phytoplankton chains at the Ushant tidal front (NW France) using the Video...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00186/29730/28148.pdf

A multi-decadal hindcast of a physical–biogeochemical model and derived oceanographic indices in the Bay of Biscay
Provedor de dados: 5
Autores: Huret, Martin; Sourisseau, Marc; Petitgas, Pierre; Struski, Caroline; Leger, Fabien; Lazure, Pascal.
Multiple year oceanographic simulations (hindcast) are identified as a priority oceanography product for fisheries and environment studies since they provide a unique continuous long-term dataset allowing integrated assessment of the ocean state and evolution. We performed a 37 year (1972–2008) hindcast run with a coupled physical–biogeochemical model in the Bay of Biscay. The coupled model and the hindcast configuration are described. A model skill assessment is performed with a large set of in-situ data. Average seasonal currents show major circulation patterns over the shelf. Among tracers, temperature and salinity have the best agreement, ahead of nitrates and silicates, chlorophyll, and finally phosphates and ammonium. For chlorophyll, improved...
Tipo: Text
Palavras-chave: Physical-biogeochemical model; Hindcast; Skill assessment; Environmental indices; Seasonal pattern; Interannual variability; Fisheries oceanography; Bay of Biscay.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00114/22538/20237.pdf

Répartition spatio-temporelle des nutriments. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Rogé, Marine.
Tipo: Text
Palavras-chave: Mers celtiques; Nutriments; Répartition spatio-temporelle; Evolution.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43930/79224.pdf

Coupling between taxonomic and functional diversity in protistan coastal communities
Provedor de dados: 5
Autores: Ramond, Pierre; Sourisseau, Marc; Simon, Nathalie; Romac, Sarah; Schmitt, Sophie; Rigaut-jalabert, Fabienne; Henry, Nicolas; De Vargas, Colomban; Siano, Raffaele.
The study of protistan functional diversity is crucial to understand the dynamics of oceanic ecological processes. We combined the metabarcoding data of various coastal ecosystems and a newly developed trait‐based approach to study the link between taxonomic and functional diversity across marine protistan communities of different size‐classes. Environmental DNA was extracted and the V4 18S rDNA genomic region was amplified and sequenced. In parallel, we tried to annotate the Operational Taxonomic Units (OTUs) from our metabarcoding dataset to 30 biological traits using published and accessible information on protists. We then developed a method to study trait correlations across protists (i.e. trade‐offs) in order to build the best functional groups....
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00478/58964/61554.pdf

Bulletin d'information PREVIMER - Informations et analyses des eaux côtières. Mars Avril 2009- n°7
Provedor de dados: 5
Autores: Lazure, Pascal; Huret, Martin; Gohin, Francis; Sourisseau, Marc; Saulquin, Bertrand; Lecornu, Fabrice; De Roeck, Yann-herve; Legrand, Jacques; Thomin, Pascale; Aoustin, Yannick; Jegou, P.; Baraer, F.; Le Stum, M.; Louazel, Stephanie; Equipe projet PREVIMER.
Sommaire * Météo, états de mer et débits des fleuves.....................2 * Caractéristiques des masses d’eau côtières..............6 * Production biologique............11 * Les faits marquants................12 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00242/35360/33860.pdf

A 38 years hindcast of a coupled physical-biogeochemical model and derived indices for fisheries oceanography
Provedor de dados: 5
Autores: Huret, Martin; Petitgas, Pierre; Sourisseau, Marc; Struski, Caroline; Leger, Fabien; Lazure, Pascal.
Operational oceanography rapidly progresses and its products become easy to access to a large community, among them fisheries scientists. The products cover both near real-time environment information (on scales of days to weeks) but also retrospective analysis providing long time series of environment parameters. Here we describe a 38 years hindcast of a coupled physical-biogeochemical model of the Bay of Biscay as well as the indices and major information that were derived from it.
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00023/13454/10466.pdf

Assessing spatial and temporal variability of phytoplankton communities' composition in the Iroise Sea ecosystem (Brittany, France): A 3D modeling approach: Part 2: Linking summer mesoscale distribution of phenotypic diversity to hydrodynamism
Provedor de dados: 5
Autores: Cadier, Mathilde; Sourisseau, Marc; Gorgues, Thomas; Edwards, Christopher A.; Memery, Laurent.
Tidal front ecosystems are especially dynamic environments usually characterized by high phytoplankton biomass and high primary production. However, the description of functional microbial diversity occurring in these regions remains only partially documented. In this article, we use a numerical model, simulating a large number of phytoplankton phenotypes to explore the three-dimensional spatial patterns of phytoplankton abundance and diversity in the Iroise Sea (western Brittany). Our results suggest that, in boreal summer, a seasonally marked tidal front shapes the phytoplankton species richness. A diversity maximum is found in the surface mixed layer located slightly west of the tidal front (i.e., not strictly co-localized with high biomass...
Tipo: Text
Palavras-chave: Plankton functional traits; Biodiversity; Biogeography; Local adaptation; Dynamical transport; Tidal front.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00367/47861/48101.pdf

Phytoplankton taxonomic and functional diversity patterns across a coastal tidal front
Provedor de dados: 5
Autores: Ramond, Pierre; Siano, Raffaele; Schmitt, Sophie; De Vargas, Colomban; Marié, Louis; Memery, Laurent; Sourisseau, Marc.
Oceanic physics at fine scale; e.g. eddies, fronts, filaments; are notoriously difficult to sample. However, an increasing number of theoretical approaches hypothesize that these processes affect phytoplankton diversity which have cascading effects on regional ecosystems. In 2015, we targeted the Iroise Sea (France) and evidenced the setting up of the Ushant tidal front from the beginning of spring to late summer. Seawater samples were taken during three sampling cruises and DNA-barcoding allowed us to investigate patterns of eukaryotic phytoplankton diversity across this front. First focusing on patterns of taxonomic richness, we evidenced that the front harbored a hotspot of eukaryotic phytoplankton diversity sustained throughout summer. We then detail...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00677/78933/81307.pdf

Comprendre, Prédire et Agir sur les efflorescences toxiques. Jusqu'où peut-on aller aujourd'hui dans le cas d'Alexandrium minutum en Penzé ?
Provedor de dados: 5
Autores: Chapelle, Annie; Andrieux, Francoise; Fauchot, Juliette; Guillaud, Jean-francois; Labry, Claire; Sourisseau, Marc; Verney, Romaric.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00105/21651/19232.pdf

Répartition spatio-temporelle des nutriments. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Roge, Marine.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Nutriments; Répartition spatio-temporelle; Evolution.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44008/79201.pdf

Species specific gene expression dynamics during harmful algal blooms
Provedor de dados: 5
Autores: Metegnier, Gabriel; Paulino, Sauvann; Ramond, Pierre; Siano, Raffaele; Sourisseau, Marc; Destombe, Christophe; Le Gac, Mickael.
Harmful algal blooms are caused by specific members of microbial communities. Understanding the dynamics of these events requires comparing the strategies developed by the problematic species to cope with environmental fluctuations to the ones developed by the other members of the community. During three consecutive years, the meta-transcriptome of micro-eukaryote communities was sequenced during blooms of the toxic dinoflagellate Alexandrium minutum. The dataset was analyzed to investigate species specific gene expression dynamics. Major shifts in gene expression were explained by the succession of different species within the community. Although expression patterns were strongly correlated with fluctuation of the abiotic environment, and more...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00622/73390/72602.pdf

Répartition spatio-temporelle de l’oxygène. Sous-région marine Golfe de Gascogne. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Daniel, Anne; Rogé, Marine.
Tipo: Text
Palavras-chave: Golfe de Gascogne; Oxygène dissous; Répartition spatio-temporelle; Dynamique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00329/44007/43579.pdf

Assessing spatial and temporal variability of phytoplankton communities' composition in the Iroise Sea ecosystem (Brittany, France): A 3D modeling approach. Part 1: Biophysical control over plankton functional types succession and distribution
Provedor de dados: 5
Autores: Cadier, Mathilde; Gorgues, Thomas; Sourisseau, Marc; Edwards, Christopher A.; Aumont, Olivier; Marie, Louis; Memery, Laurent.
Understanding the dynamic interplay between physical, biogeochemical and biological processes represents a key challenge in oceanography, particularly in shelf seas where complex hydrodynamics are likely to drive nutrient distribution and niche partitioning of phytoplankton communities. The Iroise Sea includes a tidal front called the ‘Ushant Front’ that undergoes a pronounced seasonal cycle, with a marked signal during the summer. These characteristics as well as relatively good observational sampling make it a region of choice to study processes impacting phytoplankton dynamics. This innovative modeling study employs a phytoplankton-diversity model, coupled to a regional circulation model to explore mechanisms that alter biogeography of phytoplankton in...
Tipo: Text
Palavras-chave: Iroise Sea; Tidal mixing front; Biogeochemical modeling; Phytoplankton; Functional groups; Seasonal cycle.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00352/46367/45986.pdf

Répartition spatio-temporelle des nutriments. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Rogé, Marine.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Nutriments; Répartition spatio-temporelle; Evolution.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43826/80857.pdf

Springtime zooplankton size structure over the continental shelf of the Bay of Biscay
Provedor de dados: 5
Autores: Vandromme, Pierre; Nogueira, Enrique; Huret, Martin; Lopez-urrutia, Angel; Gonzalez-nuevo Gonzalez, G.; Sourisseau, Marc; Petitgas, Pierre.
Linking lower and higher trophic levels requires special focus on the essential role played by mid-trophic levels, i.e., the zooplankton. One of the most relevant pieces of information regarding zooplankton in terms of flux of energy lies in its size structure. In this study, an extensive data set of size measurements is presented, covering parts of the western European continental shelf and slope, from the Galician coast to the Ushant front, during the springs from 2005 to 2012. Zooplankton size spectra were estimated using measurements carried out in situ with the Laser Optical Plankton Counter (LOPC) and with an image analysis of WP2 net samples (200 μm mesh size) performed following the ZooScan methodology. The LOPC counts and sizes particles within...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00221/33246/31744.pdf

Amélioration de la gestion des conditions de frontières ouvertes biogéochimiques dans les modèles physiques et biogéochimiques couplés régionaux afin de reproduire les principaux processus d’échanges côte - large. Action vers une Modélisation Intégrée Côtière Opérationnelle (AMICO).
Provedor de dados: 5
Autores: Pinazo, Christel; Ross, Oliver; Diaz, F.; Doglioli, A.m.; D'Ortenzio, F.; Estournel, C.; Forget, P.; Garnier, Valerie; Gutknecht, E.; Kersale, M.; Kessouri, F.; Lathuilière, C.; Marie, Louis; Marmain, J.; Marsaleix, P.; Perruche, C.; Petrenko, A.; Reffray, G.; Sourisseau, Marc; Taillandier, V.; Taupier-letage, I.; Testor, P.; Thouvenin, Benedicte; Ulses, C.; Eldin, G.
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00292/40336/41772.pdf

Krill diel vertical migration fine dynamics, nocturnal overturns, and their roles for aggregation in stratified flows (vol 65, pg 574, 2008)
Provedor de dados: 5
Autores: Sourisseau, Marc; Simard, Y.; Saucier, F. J.
A set of high-resolution observations on short-term dynamics of krill diel vertical migrations (DVM) in the St. Lawrence Estuary are presented here, including vertical mass transfer measurements from multifrequency echo sounding coupled with stratified net sampling and tracers of individual vertical movements from stomach pigments over a 72 h period. The data set is supplemented by vertical migration speeds and biomass diel patterns from ADCP (acoustic Doppler current profiler) time series lasting up to 3 months. All krill always rapidly migrated to the surface in synchrony at sunset. Soon after the ascent, fed krill started to swim downward. A scattering layer was then formed at their daytime depth with sometimes a significant backscatter at intermediate...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7373.pdf

The Seasonal and Inter-Annual Fluctuations of Plankton Abundance and Community Structure in a North Atlantic Marine Protected Area
Provedor de dados: 5
Autores: Benedetti, Fabio; Jalabert, Laëtitia; Sourisseau, Marc; Becker, Beatriz; Cailliau, Caroline; Desnos, Corinne; Elineau, Amanda; Irisson, Jean-olivier; Lombard, Fabien; Picheral, Marc; Stemmann, Lars; Pouline, Patrick.
Marine Protected Areas have become a major tool for the conservation of marine biodiversity and resources. Yet our understanding of their efficacy is often limited because it is measured for a few biological components, typically top predators or species of commercial interest. To achieve conservation targets, marine protected areas can benefit from ecosystem-based approaches. Within such an approach, documenting the variation of plankton indicators and their covariation with climate is crucial as plankton represent the base of the food webs. With this perspective, we sought to document the variations in the emerging properties of the plankton to better understand the dynamics of the pelagic fishes, mammals and seabirds that inhabit the region. For the...
Tipo: Text
Palavras-chave: Iroise Sea; Plankton; MPA; Temporal variability; Community composition; Size structure.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00490/60213/63561.pdf

Modélisation couplée physique-biogéochimie du golfe de Gascogne sur la période 1971-2007
Provedor de dados: 5
Autores: Huret, Martin; Struski, Caroline; Leger, Fabien; Petitgas, Pierre; Lazure, Pascal; Sourisseau, Marc.
Une simulation 'hindcast' de la dynamique physique et biogéochimique du golfe de Gascogne a été réalisée pour la période 1971-2007 à l'aide du modèle ECO-MARS3D. Ce modèle couplant physique et biogéochimie fournit une série longue de données simulées, moyennées ou intégrées sur 3 jours (température, salinité, sels nutritifs, phytoplancton, zooplancton), qui sont ensuite utilisées pour des calculs d'indices hydrologiques 2D synthétiques (indices méso-échelle : stratification, upwellings, surface tourbillonnaire ; indices biologiques : chlorophylle-a de surface, production primaire intégrée). Nous nous proposons dans ce document de présenter la configuration et les forçages utilisés pour cette simulation, et de lister les différentes variables sauvegardées...
Tipo: Text
Palavras-chave: Projet FP6 RECLAIM; Halieutique; Indices hydrologiques; Hindcast; ECO MARS3D; Modélisation couplée; Golfe de Gascogne.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/rapport-5164.pdf

Significance of Plankton Community Structure and Nutrient Availability for the Control of Dinoflagellate Blooms by Parasites: A Modeling Approach
Provedor de dados: 5
Autores: Alves-de-souza, Catharina; Pecqueur, David; Le Floc'H, Emilie; Mas, Sebastien; Roques, Cecile; Mostajir, Behzad; Vidussi, Franscesca; Velo-suarez, Lourdes; Sourisseau, Marc; Fouilland, Eric; Guillou, Laure.
Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00274/38478/36938.pdf

Répartition spatio-temporelle de l’oxygène. Sous-région marine Mers celtiques. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Daniel, Anne; Rogé, Marine.
Tipo: Text
Palavras-chave: Mers celtiques; Oxygène dissous; Répartition spatio-temporelle; Dynamique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00328/43929/43502.pdf

Advancing Observation of Ocean Biogeochemistry, Biology, and Ecosystems With Cost-Effective in situ Sensing Technologies
Provedor de dados: 5
Autores: Wang, Zhaohui Aleck; Moustahfid, Hassan; Mueller, Amy V.; Michel, Anna Pm; Mowlem, Matthew; Glazer, Brian T.; Mooney, T. Aran; Michaels, William; Mcquillan, Jonathan S.; Robidart, Julie C.; Churchill, James; Sourisseau, Marc; Daniel, Anne; Schaap, Allison; Monk, Sam; Friedman, Kim; Brehmer, Patrice.
Advancing our understanding of ocean biogeochemistry, biology, and ecosystems relies on the ability to make observations both in the ocean and at the critical boundaries between the ocean and other earth systems at relevant spatial and temporal scales. After decades of advancement in ocean observing technologies, one of the key remaining challenges is how to cost-effectively make measurements at the increased resolution necessary for illuminating complex system processes and rapidly evolving changes. In recent years, biogeochemical in situ sensors have been emerging that are threefold or more lower in cost than established technologies; the cost reduction for many biological in situ sensors has also been significant, although the absolute costs are still...
Tipo: Text
Palavras-chave: In situ; Sensor; OceanObs; Ocean technology; EOVs; Biogeochemistry; Biology; Cost effective.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00514/62567/66921.pdf

Répartition spatio-temporelle de l’oxygène. Sous-région marine Manche - Mer du Nord. Evaluation initiale DCSMM.
Provedor de dados: 5
Autores: Sourisseau, Marc; Daniel, Anne; Rogé, Marine.
Tipo: Text
Palavras-chave: Manche; Mer du Nord; Oxygène dissous; Répartition spatio-temporelle; Dynamique.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00327/43825/43399.pdf

Processes leading to the coexistence of a host and its parasitoid in homogeneous environments: The role of an infected dormant stage
Provedor de dados: 5
Autores: Arancio, Marc; Sourisseau, Marc; Souissi, Sami.
Theoretical studies have usually been used to explain host–parasitoid persistence in conditions of spatial heterogeneity or in homogeneous environments with specific conditions. In shallow estuaries where spatial heterogeneity is prevented by tides and river input, a common host–parasitoid system (dinoflagellate-Amoebophrya spp.) is able to persist even in the absence of specific conditions described in the literature. Recent observations have revealed that the cyst stage (during which the dinoflagellate host can survive in difficult environmental conditions in a dormant stage) can be infected by the parasitoid. The encystment/excystment process is suspected to be the basis for the long-term persistence of the system. In this work, the coexistence of...
Tipo: Text
Palavras-chave: Individual-based model; Dinoflagellate; Parasitoid; Amoebophrya; Host-parasite interactions; Sources of coexistence.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00180/29119/27692.pdf

Climate Variability and Oceanographic Settings Associated with Interannual Variability in the Initiation of Dinophysis acuminata Blooms
Provedor de dados: 5
Autores: Diaz, Patricio A.; Reguera, Beatriz; Ruiz-villarreal, Manuel; Pazos, Yolanda; Velo-suarez, Lourdes; Berger, Henrick; Sourisseau, Marc.
In 2012, there were exceptional blooms of D. acuminata in early spring in what appeared to be a mesoscale event affecting Western Iberia and the Bay of Biscay. The objective of this work was to identify common climatic patterns to explain the observed anomalies in two important aquaculture sites, the Galician R as Baixas (NW Spain) and Arcachon Bay (SW France). Here, we examine climate variability through physical-biological couplings, Sea Surface Temperature (SST) anomalies and time of initiation of the upwelling season and its intensity over several decades. In 2012, the mesoscale features common to the two sites were positive anomalies in SST and unusual wind patterns. These led to an atypical predominance of upwelling in winter in the Galician R as,...
Tipo: Text
Palavras-chave: Dinophysis acuminata; Climate variability; Upwelling patterns; River plumes; Exceptional algal blooms; Predictive models.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00180/29157/27554.pdf

The ZooCAM, a new in-flow imaging system for fast onboard counting, sizing and classification of fish eggs and metazooplankton
Provedor de dados: 5
Autores: Colas, Florent; Tardivel, Morgan; Perchoc, Jonathan; Lunven, Michel; Forest, Bertrand; Guyader, Gerard; Danielou, Marie-madeleine; Le Mestre, Sophie; Bourriau, Paul; Antajan, Elvire; Sourisseau, Marc; Huret, Martin; Petitgas, Pierre; Romagnan, Jean-baptiste.
In this paper we present the ZooCAM, a system designed to digitize and analyse on board large volume samples of preserved and living metazooplankton (i.e. multicellular zooplankton) and fish eggs &gt; 300 µm ESD. The ZooCAM has been specifically designed to overcome the difficulties to analyse zooplankton and fish eggs in the framework of the PELGAS survey, and provide high frequency data. The ZooCAM fish eggs counts were comparable to those done with a dissecting microscope. The ZooCAM enabled the accurate prediction and fast on board validation of staged anchovy and sardine eggs in almost real time after collection. A comparison with the ZooScan, on a more complex zooplanktonic community, provided encouraging results on the agreement between the 2...
Tipo: Text
Palavras-chave: ZooCAM; In-flow imaging; Fish eggs; Zooplankton; Ecosystemic survey.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00407/51833/52432.pdf

Tidal cycle control of biogeochemical and ecological properties of a macrotidal ecosystem
Provedor de dados: 5
Autores: Cadier, Mathilde; Gorgues, Thomas; Lhelguen, Stephane; Sourisseau, Marc; Memery, Laurent.
In some regions, tidal energy can be a key factor in the generation of variability in physical and biogeochemical properties throughout the water column. We use a numerical model resolving tidal cycles and simulating diversity in phytoplankton to assess the impact of tidal mixing on vertical stability and phytoplankton community (total biomass and diversity) in a macrotidal sea (Iroise Sea, France). Two different time scales have been considered: semi-diurnal and spring/neap tidal cycles. Our results show that the latter is the one primarily influencing the phytoplankton growth conditions by modifying the vertical stratification. During spring tide, the growth is rather light-limited whereas neap tide conditions lead to vertical stabilization and better...
Tipo: Text
Palavras-chave: Macrotidal ecosystem; Spring; Neap tidal cycle; Semidiurnal cycle; Phytoplankton communities; Diversity; Competition.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00395/50612/51325.pdf

Alexandrium minutum growth controlled by phosphorus An applied model
Provedor de dados: 5
Autores: Chapelle, Annie; Labry, Claire; Sourisseau, Marc; Lebreton, Carole; Youenou, Agnes; Crassous, Marie-pierre.
Toxic algae are a worldwide problem threatening aquaculture public health and tourism Alexandrium a toxic dinoflagellate proliferates in Northwest France estuaries (i e the Penze estuary) causing Paralytic Shellfish Poisoning events Vegetative growth and in particular the role of nutrient uptake and growth rate are crucial parameters to understand toxic blooms With the goal of modelling in situ Alexandrium blooms related to environmental parameters we first try to calibrate a zero-dimensional box model of Alexandrium growth This work focuses on phosphorus nutrition Our objective is to calibrate Alexandrium minutum as well as Heterocapsa triquetra (a non-toxic dinoflagellate) growth under different rates of phosphorus supply other factors being optimal and...
Tipo: Text
Palavras-chave: Toxic algal blooms; Alexandrium; Phosphorus uptake; Models; Competition; Northwest France.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00018/12901/9905.pdf