References of "Collignon, Amandine"
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See detailLe plastique dans les océans, la Méditerranée est-elle menacée?
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Goffart, Anne ULg

Scientific conference (2015, March 05)

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See detailControl of plankton phenology by climate variation in a Mediterranean coastal area : results from a long-term study (1979-2011)
Goffart, Anne ULg; Collignon, Amandine ULg; Hecq, Jean-Henri ULg

Conference (2015, March)

Physical processes are known to play major roles in marine plankton succession. However, few studies have addressed the mechanisms that regulate phyto- and zooplankton phenology in a context of changing ... [more ▼]

Physical processes are known to play major roles in marine plankton succession. However, few studies have addressed the mechanisms that regulate phyto- and zooplankton phenology in a context of changing climate. Here we used a unique long-term (1979-2011) time series performed in a Mediterranean coastal area unbiased by local anthropogenic pressure (PHYTOCLY station, Bay of Calvi, Corsica) to understand how environmental forcing affects the timing, duration and magnitude of the winter-spring phyto- and zooplankton blooms. We showed that phyto- and zooplankton blooms were bottom-up controlled by the establishment of favourable abiotic conditions, i.e. nutrient replenishment by vertical mixing under specific water temperature and wind conditions, for which thresholds were defined. According to the intensity of winter characteristics, there were strong differences in both the abundance and composition of phyto- and zooplankton during the winter-spring period. Our study is consistent with the recent reports that, when occurring, diatoms peaks were added to the initial phytoplankton groups instead of replacing them. In contrast, zooplankton groups followed a replacement sequence. Based on the results provided by our time series, we show that plankton phenology in the Bay of Calvi is highly controlled by climate variation and exhibits contrasted patterns in response to different scenarios of environmental forcing. [less ▲]

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See detailBiodiversity and seasonal variations of zooneuston in the northwestern Mediterranean Sea
Collard, France ULg; Collignon, Amandine ULg; Hecq, Jean-Henri ULg et al

in Belgian Journal of Zoology (2015), 145(1), 40-48

Neuston includes animals and plants inhabiting the surface layer of the water column. The neustonic area is an accumulation zone for bacteria, organic molecules but also terrestrial debris. The surface ... [more ▼]

Neuston includes animals and plants inhabiting the surface layer of the water column. The neustonic area is an accumulation zone for bacteria, organic molecules but also terrestrial debris. The surface layer is also the air/water exchange region. Therefore, neustonic organisms are directly exposed to several constraints such as wind stress and turbulence. The present study aims to characterize the zooneuston in terms of abundance and biodiversity and to evaluate the impacts of wind stress on neustonic abundance. Zooneustonic and zooplanktonic (depth of 5 meters) samples were collected twice a month between 30th August 2011 and 10th July 2012 in Calvi Bay, Corsica. Zooneustonic biodiversity was high and, notably, twenty-eight copepod genera were identified. Among these copepods, several organisms, belonging to the Pontellidae family, were much more frequent in neuston than in underlying plankton and their abundance depended on wind direction. Taxon-specific trends in seasonal abundance variation were present. For example, individuals of the Acantharia Lithoptera spp. were found in summer whereas the Pontellidae Anomalocera patersoni appeared in winter. Overall, our data provide a first step towards a better knowledge of neuston community structure in the Mediterranean Sea. [less ▲]

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See detailAbundance and variability of jellyfishes in the Bay of Calvi, Corsica
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Goffart, Anne ULg

Scientific conference (2014, May 29)

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See detailAbondance et variabilité des méduses en Baie de Calvi (Corse)
Collignon, Amandine ULg

Doctoral thesis (2014)

L’importance et la variabilité temporelle des méduses calycophores et de la méduse schyphozoaire, Pelagia noctiluca en Baie de Calvi (Corse) ont été étudiées en utilisant une série temporelle planctonique ... [more ▼]

L’importance et la variabilité temporelle des méduses calycophores et de la méduse schyphozoaire, Pelagia noctiluca en Baie de Calvi (Corse) ont été étudiées en utilisant une série temporelle planctonique hebdomadaire de 2003 à 2013. Cette variabilité a été comparée à celles des variables biotiques et abiotiques grâce à la technique du calcul des anomalies saisonnières et interannuelles. La diversité des méduses siphonophores calycophores a été décrite et les critères taxonomiques permettant d’identifier les espèces dominantes (Chelophyes appendiculata, Lensia subtilis, Abylopsis tetragona et Muggiaea atlantica) et de leurs stades de développement ont été précisés. Le cycle de développement de Chelophyes appendiculata a été établi sur base de la variation saisonnière climatique des différents stades moyennée sur les 10 années. Cette espèce est rencontrée toute l’année et présente deux générations, par an. Ce cycle est en phase avec les périodes d’abondance du zooplancton et en particulier des copépodes. Il s’inscrit dans la séquence des événements planctoniques liés à stratification de la colone d’eau. La variation interannuelle se marque par la succession des différentes espèces dont l’abondance augmente sur une période de quatre ans environ. Ainsi au cours des 10 ans, Chelophyes est progressivement remplacé par Lensia. La corrélation entre la moyenne annuelle de l’abondance des eudoxies et celle de la température de surface est très significative et suggère le contrôle de la reproduction par la température. Une relation inverse de l’abondance des stades polygastriques et l’abondance du zooplancton suggère un contrôle de ces méduses sur ce dernier. La distribution spatiale des calycophores a été étudiée au large de la Corse en relation avec les différentes masses d’eau et structures hydrologiques associées au front Liguro-provençal. Les plus fortes abondances sont situées au niveau du plateau continental. Dans 90% des échantillons de surface de fortes abondances de microplastiques étaient associées au zooplancton et aux méduses en particulier. L’étude de la variabilité de la méduse Pelagia noctiluca en Baie de Calvi a confirmé que les invasions obéissent à un cycle pluriannuel indépendamment de la pollution. La distribution en essaims a été étudiée en relation avec les contraintes du milieu. [less ▲]

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See detailAnnual variation in neustonic micro- and meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean–Corsica)
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Galgani, François et al

in Marine Pollution Bulletin (2014), 79(1-2), 293-298

The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi 23 (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size ... [more ▼]

The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi 23 (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size classes, small microplastics (0.2–2 mm), large microplastics (2–5 mm) and mesoplastics (5–10 mm). 74% of the 38 samples contained plastic particles of varying composition: e.g. filaments, polystyrene, thin plastic films. An average concentration of 6.2 particles/100 m2 was observed. The highest abundance values (69 particles/100 m2) observed occurred during periods of low offshore wind conditions. These values rose in the same order of magnitude as in previous studies in the North Western Mediterranean. The relationships between the abundance values of the size classes between zooplankton and plastic particles were then examined. The ratio for the intermediate size class (2–5 mm) reached 2.73. This would suggest a potential confusion for predators regarding planktonic prey of this size class. [less ▲]

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See detailAtlas du zooplancton des eaux côtières corses, version du 04/06/2014
Hecq, Jean-Henri ULg; Collignon, Amandine ULg; Goffart, Anne ULg

Book published by Travail de synthèse réalisé à la demande de l’Agence de l’Eau RMC, France (2014)

Cet atlas a pour but : de fournir, sous forme de manuel pratique rédigé en français, un guide illustré des principaux taxons zooplanctoniques, des protistes et des méduses aux céphalopodes; d’illustrer la ... [more ▼]

Cet atlas a pour but : de fournir, sous forme de manuel pratique rédigé en français, un guide illustré des principaux taxons zooplanctoniques, des protistes et des méduses aux céphalopodes; d’illustrer la biodiversité et l’écologie des espèces dominantes et de quelques espèces moins fréquentes mais spectaculaires, de synthétiser, sous un graphisme attrayant, les informations permettant l’identification des organismes présentés.   Pour chaque espèce ou groupe d’espèces, une fiche descriptive renseigne le nom latin et la classification. Les éléments morphologiques qui permettent de différencier les espèces présentées sont soulignés. Les fiches sont illustrées par des photos originales réalisées sur du plancton prélevé en Baie de Calvi (Corse), et dans certains cas, de notes sur la biologie et l'écologie. L’atlas du zooplancton des eaux côtières corses s’adresse prioritairement aux gestionnaires de l’environnement, aux techniciens de la mer, aux naturalistes ainsi qu’aux étudiants et enseignants des Masters en Sciences marines. Il est conçu pour être complété par les utilisateurs qui peuvent insérer leurs propres fiches au sein des groupes présentés. [less ▲]

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See detailContrasting patterns of phytoplankton communities in two coastal ecosystems in relation to environmental factors (Corsica, NW Mediterranean Sea)
Garrido, Marie; Koeck, Barbara; Goffart, Anne ULg et al

in Diversity (2014), 6

Corsica Island is a sub-basin of the Northwestern Mediterranean Sea, with hydrological features typical of both oligotrophic systems and eutrophic coastal zones. Phytoplankton assemblages in two coastal ... [more ▼]

Corsica Island is a sub-basin of the Northwestern Mediterranean Sea, with hydrological features typical of both oligotrophic systems and eutrophic coastal zones. Phytoplankton assemblages in two coastal ecosystems of Corsica (the deep Bay of Calvi and the shallow littoral of Bastia) show contrasting patterns over a one-year cycle. In order to determine what drives these variations, seasonal changes in littoral phytoplankton are considered together with environmental parameters. Our methodology combined a survey of the physico-chemical structure of the subsurface water with a characterization of the phytoplankton community structure. Sampling provided a detailed record of the seasonal changes and successions that occur in these two areas. Results showed that the two sampled stations presented different phytoplankton abundance and distribution patterns, notably during the winter–spring bloom period. Successions in pico-, nano-, and microphytoplankton communities appeared mainly driven by differences in the ability to acquire nutrients, and in community-specific growth rates. Phytoplankton structure and dynamics are discussed in relation to available data on the Northwestern Mediterranean Sea. These results confirm that integrated monitoring of coastal areas is a requisite for gaining a proper understanding of marine ecosystems. [less ▲]

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See detailEtude de la variation saisonnière des quantités de microplastiques de la zone de Calvi
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Goffart, Anne ULg

Report (2013)

L’étude a pour objectif de collecter des données d’abondance de microplastiques au cours d’un cycle annuel dans une zone peu impactée par l’activité anthropique locale, la Baie de Calvi (Corse). Une ... [more ▼]

L’étude a pour objectif de collecter des données d’abondance de microplastiques au cours d’un cycle annuel dans une zone peu impactée par l’activité anthropique locale, la Baie de Calvi (Corse). Une attention particulière est portée aux relations entre l’abondance des microplastiques et celle du zooplancton, ainsi qu’à la nature des organismes qui colonisent les microplastiques. [less ▲]

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See detailNutrient and phytoplankton responses to external forcing in a Mediterranean coastal area unbiaised by terrestrial inputs and local activities (Calvi, Corsica)
Goffart, Anne ULg; Hecq, Jean-Henri ULg; Collignon, Amandine ULg et al

Poster (2013, January)

We present a synthesis of a long-term (1979-2011) high-resolution study performed in the oligotrophic Bay of Calvi (Corsica, northwestern Mediterranean). We explore and discuss the mechanisms controlling ... [more ▼]

We present a synthesis of a long-term (1979-2011) high-resolution study performed in the oligotrophic Bay of Calvi (Corsica, northwestern Mediterranean). We explore and discuss the mechanisms controlling the interannual variability of both nutrient and phytoplankton bloom dynamics. [less ▲]

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See detailUNDERSTANDING DRASTIC CHANGES IN ZOOPLANKTON AND MEDUSAE COMMUNITIES OVER THE 2003-2011 PERIOD IN THE MEDITERRANEAN SEA (CORSICA)
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Goffart, Anne ULg

in 2012 ASLO aquatic sciences meeting : Voyages of discovery (2012, July)

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See detailStare-Capmed : Présentation générale du projet et exemple d'une action : "Impact de l'ancrage sur la dynamique des herbiers de posidonies".
Michel, Loïc ULg; Champenois, Willy ULg; Borges, Alberto ULg et al

Conference (2012, May 16)

STARE-CAPMED (STAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts) est un projet de recherche mis en place par Stareso S.A.S. depuis ... [more ▼]

STARE-CAPMED (STAtion of Reference and rEsearch on Change of local and global Anthropogenic Pressures on Mediterranean Ecosystems Drifts) est un projet de recherche mis en place par Stareso S.A.S. depuis janvier 2012. Il a pour objectif d’établir un site de référence à long terme pour la compréhension, par la recherche fondamentale, des processus de l’évolution des écosystèmes méditerranéens côtiers et océaniques en réponse aux changements actuels globaux et locaux des pressions anthropiques. Centré sur la Baie de Calvi et le proche large, il vise à fournir un référentiel basé sur des mesures à haute fréquence qui doivent pouvoir complémenter les réseaux de surveillance basse fréquence et de recherches existants et ainsi faire progresser la compréhension des processus. En outre, le projet doit fournir aux utilisateurs finaux (collectivités locales et régionales, administrations nationales, ...) des orientations de gestion basées sur l’analyse étayée des processus en jeux. Financé par l’Agence de l’eau RMC et la Collectivité Territoriale de Corse, le projet, multidisciplinaire, se décline actuellement selon 10 axes de travail : • Suivi du cadre hydrographique et physico-chimique • Suivi et quantification des pressions anthropiques • Ecosystème planctonique • Benthos de substrat meuble • Benthos de substrat dur et faune vagile • Phanérogames marines et écosystèmes associés • Mouillages et processus d’altération des herbiers de posidonies • Ecotoxicologie et polluants émergents • Bilan CO2 et métabolisme des écosystèmes • Zones protégées, espèces nouvelles, recrutement Pour chacun de ces axes, la stratégie d’échantillonnage est basée sur la comparaison de données obtenues durant des périodes où l’impact anthropique est faible (octobre-avril) avec celles obtenues durant des périodes de pression intense (mai-septembre), et sur la comparaison de données issues de sites de référence peu impactés avec celles provenant de sites où l’impact anthropique est reconnu. A titre d’exemple, le but de l’action "Mouillages et processus d’altération des herbiers de posidonies" est de mettre en évidence les conséquences des altérations liées à l’arrachage de faisceaux de posidonies sur la vitalité de l’herbier. Des zones où la pression de mouillage est reconnue seront définies sur base des travaux de cartographie de l’herbier, également réalisés dans le cadre du projet STARE-CAPMED. Elles seront comparées avec des zones d’herbiers sains témoins par la caractérisation du sédiment (mesures de compacité in situ, mesures des concentrations en O2 et nutriments et du pH de l’eau interstitielle, granulométrie et teneur en matière organique du sédiment, proportions de rhizomes et morts) ainsi que par la définition de l’état physiologique des faisceaux de posidonies (mesures biométriques classiques, analyses des contenus élémentaires en carbone, azote et phosphore) et par l’application d’indices écologiques définis par la DCE (PREI, BIPO, …). Les résultats obtenus permettront d’avoir une vue d’ensemble des processus par lesquels l’impact physique des mouillages de bateaux de plaisance occasionne des dégâts aux herbiers de posidonies. Ils pourront ainsi fournir une base de connaissances solide aux gestionnaires soucieux de limiter cet impact. [less ▲]

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See detailAccumulation de particules de microplastiques dans le neuston en Méditerranée Occidentale et au large de la Corse
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Collard, France ULg et al

in Séminaire sur le milieu marin : 14 au 16 mai 2012 STARESO Corse (2012, May 13)

Des mesures réalisées lors de diverses campagnes océanographiques ont montré la présence de microparticules de plastiques de diverses natures à la surface des mers avec de hauts niveaux de concentration ... [more ▼]

Des mesures réalisées lors de diverses campagnes océanographiques ont montré la présence de microparticules de plastiques de diverses natures à la surface des mers avec de hauts niveaux de concentration et une large dispersion géographique. La taille de ces microplastiques est inférieure à 5 mm et voisine de celle du mésozooplancton. Ces microplastiques s’accumulent dans la couche de surface de la mer qui constitue l’habitat neustonique et qui héberge des assemblages zooplanctoniques particulièrement adaptés à ces conditions extrèmes. Cet habitat est essentiel pour la ponte et la survie des œufs de nombreux poissons et pour le recrutement des juvéniles. Une étude récente que nous avons réalisée au niveau du bassin Nord Occidental Méditerranéen et au large de la Corse (Campagne MED) a montré des concentrations de 0.116 particules/m2 et un rapport moyen de la masse de microplastique à celle du mésozooplancton de 0.5. Ceci nous suggère la potentialité d’une confusion entre les proies et les microplastiques pour les organsismes se nourrissant de zooplancton (Collignon et al., 2012). Une étude de la variabilité de ces microplastiques dans le neuston et l’impact sur celui-ci est actuellement en cours en Baie de Calvi à STARESO. Références : Collignon, A., Hecq, J.-H., Galgani, F., Voisin, P., Collard, F., Goffart, A., 2012. Neustonic microplastic and zooplankton in the North Western Mediterranean Sea. Mar. Pollut. Bull. (In Press). http://dx.doi.org/10.1016/j.marpolbul.2012.01.011 [less ▲]

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See detailNeustonic microplastic and zooplankton in the North Western Mediterranean Sea
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Galgani, François et al

in Marine Pollution Bulletin (2012), 64

Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22th and 25th ... [more ▼]

Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3-5 mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m² was observed. The highest abundances (> 0.36 particles/m²) were observed in the shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for zooplankton feeders. [less ▲]

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See detailResponse of plankton communities of the Bay of Calvi (northwestern Mediterranean) to climate variation over the past three decades
Goffart, Anne ULg; Collignon, Amandine ULg; Hecq, Jean-Henri ULg

in Symposium "Vulnerability of coastal ecosystems to global change and extreme events", Biarritz, France, 18-21 October 2011 (2011, October)

Long-term changes of surface plankton dynamics are studied from three decades at a permanent station in the oligotrophic Bay of Calvi (Corsica, northwestern Mediterranean) where water quality is unbiased ... [more ▼]

Long-term changes of surface plankton dynamics are studied from three decades at a permanent station in the oligotrophic Bay of Calvi (Corsica, northwestern Mediterranean) where water quality is unbiased by terrestrial inputs. As a distinctive feature of the Bay, a plurimodal plankton bloom occurs generally between January and April, with very large interannual variability reaching one order of magnitude from one year to another. Later in the season, the plankton biomass remains very low from May to December. Contrarily to the 1979 - 1998 period where a continuous decrease of phyto- and zooplankton biomasses was observed, observations from the last decade (1999 - 2011) emphasize abrupt changes in plankton biomass and bloom duration from one year to another in response to succession of mild and rigorous winters. Studies conducted to understand mechanisms controlling plankton variability emphasize a close relationship between winter wind stress intensity, water temperature, nutrient inputs and phytoplankton biomass. Total phytoplankton biomass is maximum during years characterized by high winter wind stress and low winter water temperature. From a specific point of view, flagellates are always the dominant component of the winter - spring phytoplankton communities. However, diatoms tend to be more abundant during rigorous winter years. Shifts in phytoplankton community structure contribute to control the dynamics of zooplankton that rely on phytoplankton as food and influence the temporal succession of zooplankton assemblages. Time-series results indicate the high sensitivity of the plankton ecosystem to climate change and confirm that the Bay of Calvi reacts rapidly to external perturbations, which are driven by climate variation. [less ▲]

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See detailJellyfish outbreaks in the Bay of Calvi (Corsica)
Hecq, Jean-Henri ULg; Goffart, Anne ULg; Collignon, Amandine ULg et al

Conference (2010, October)

The interannual variations of the Schyphozoan jellyfish Pelagia noctiluca is estimated by weekly measurements in the Bay of Calvi (Corsica) from 2003. The mean annual abundance reaches a dramatic maximum ... [more ▼]

The interannual variations of the Schyphozoan jellyfish Pelagia noctiluca is estimated by weekly measurements in the Bay of Calvi (Corsica) from 2003. The mean annual abundance reaches a dramatic maximum in 2006. The medusae appear by migration of active swarms on the shelf and at the external limit of the Bay. Degraded individuals drift as passive swarms, throughout inner side of the Bay and embayment. [less ▲]

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See detailSpatial variability of the Siphonophora along the radial Calvi-Nice (Corsican side)
Collignon, Amandine ULg; Hecq, Jean-Henri ULg; Goffart, Anne ULg

Poster (2010)

The spatial distribution of the Siphonophorae has been examined, in Occidental Mediterranean, along the radial Calvi-Nice, from Calvi up to 30 miles offshore in September 2009. The variation of the ... [more ▼]

The spatial distribution of the Siphonophorae has been examined, in Occidental Mediterranean, along the radial Calvi-Nice, from Calvi up to 30 miles offshore in September 2009. The variation of the abundance of the plankton and of the Siphonophorae was put in relation with the hydrological structures of the Liguro-Provençal front. This structure separates the coastal waters of Atlantic origin from the offshore central Mediterranean waters of deep origin. Globally, the larger abundances of Siphonophorae were present in inshore waters between the front and the coast. Both nectophores (asexual stage) and gonophores and bracts (reproductive stage) of Lensia subtilis occured only in the inshore waters. The nectophores of Chelophyes appendiculata occured at all sampling stations with no significative variation. However, the abundance of the bracts and the gonophores increases when we get closer to the coast. This allows us to hypothesize that the maximum of reproduction is located in waters close to the coast. On the other hand, the larvae abundance of calycophoran siphonophores, in the plankton samples, increase from the coastal waters to the offshore waters with a maximum of abundance at the station located at 25 miles offshore. That contradiction could be explained by plankton net avoidance of small larvae, by current transport or by variable hatching success at the various stations. The larvae of physonect siphonophores are more often found offshore. [less ▲]

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See detailInterannual variation (2003-2008) of Calycophoran siphonophores in the Bay of Calvi (Corsica)
Collignon, Amandine ULg; Goffart, Anne ULg; Hecq, Jean-Henri ULg

in Proceedings of the 39th CIESM Congress (2010)

The interannual variation of the calycophoran siphonophores was investigated in the Bay of Calvi (Corsica) from 2003 to 2008. The dominant species, Chelophyes appendiculata, was present throughout the ... [more ▼]

The interannual variation of the calycophoran siphonophores was investigated in the Bay of Calvi (Corsica) from 2003 to 2008. The dominant species, Chelophyes appendiculata, was present throughout the year, with a maximum of reproduction during the summer. Large variations of abundance occur from year to year. The study of the developmental stages along the year allows us to establish its life cycle, which seems to be correlated with the temperature and mesozooplancton abundance. The cycle takes place each year with a similar seasonal pattern throughout all the study. Other species as Abylopsis tetragona and Lensia sp., were also present in lower abundance. [less ▲]

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See detailProblematic of the Pelagia noctiluca outbreaks in the Bay of Calvi (Corsica)
Hecq, Jean-Henri ULg; Goffart, Anne ULg; Collignon, Amandine ULg et al

in Proceedings of the 39th CIESM Congress (2010)

The interannual variations of the Schyphozoan jellyfish Pelagia noctiluca is estimated by weekly measurements in the Bay of Calvi (Corsica) from 2003. The mean annual abundance reaches a dramatic maximum ... [more ▼]

The interannual variations of the Schyphozoan jellyfish Pelagia noctiluca is estimated by weekly measurements in the Bay of Calvi (Corsica) from 2003. The mean annual abundance reaches a dramatic maximum in 2006. The medusae appear by migration of active swarms on the shelf and at the external limit of the Bay. Degraded individuals drift as passive swarms, throughout inner side of the Bay and embayments. [less ▲]

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See detailLa variabilité inter et intra-annuelle des méduses en Baie de Calvi
Collignon, Amandine ULg

Master's dissertation (2009)

During the last decade, there has been a dramatic increase in jellyfish biomass all over the world. They are infamous for their negative effects on humans. Indeed, they interfere with the tourism by ... [more ▼]

During the last decade, there has been a dramatic increase in jellyfish biomass all over the world. They are infamous for their negative effects on humans. Indeed, they interfere with the tourism by stinging swimmers, with the fishing by clogging nets, with the aquaculture by killing the fishes in net-pens and with the power plants by obstructing cooling-water intake railings. They also have indirect effects on fisheries by feeding on zooplankton and ichthyoplankton, and, therefore, are predators and potential competitors for fishes. The temporal and horizontal distributions of Medusae in the Bay of Calvi were investigated by an analysis of weekly planktonic time series (2003-2008) collected at STARESO, University of Liege’s Oceanographic field station located in Corsica (FRANCE). Firstly, our study showed similar seasonal standards throughout the year for the majority of jellyfish communities. However, we noticed an important fluctuation in quantity from year to year. Secondly, we focused on the two most common species of jellyfish found in this area; the calycophoran siphonophore, Chelophyes appendiculata (Eschscholtz, 1829) and the scyphozoan medusa Pelagia noctiluca (Forskal, 1775). The life cycle of Chelophyes appendiculata was established by using the different stages found during diverse periods into our samples and seemed to be correlated with the temperature of the water. The analysis of the spatial distribution of Pelagia noctiluca emphasizes the fact that during the 2006 bloom; most of the organisms were located far away from the coastlines where they were forming active swarms of 200 m of length with 5 to 10 individuals per m³. In the swarms, the individuals are healthy and swim actively in the upper layer (10 to 60 m) of the water with tentacles extended, probably in order to catch the food. The swarms are generally close to wind’s protected areas where the turbulences of the surface are reduced and zooplankton is accumulating. The year following a high zooplankton biomass was characterized by an increase of the number of jellyfishes. We can thus conclude that the overgrowth of adult jellyfishes seems to be related with the availability of zooplankton communities. [less ▲]

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