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Auteur Lezama-Ochoa, A.; Grados, D.; Lebourges Dhaussy, A.; Irigoien, X.; Chaigneau, A.; Bertrand, A.
Titre Biological characteristics of the hydrological landscapes in the Bay of Biscay in spring 2009 Type Article scientifique
Année 2015 Publication Revue Abrégée Fisheries Oceanography
Volume 24 Numéro 1 Pages 26-41
Mots-Clés acoustics; Bay of Biscay; Biogeography; fish; horizontal distribution; hydrological structures; macrozooplankton; patterns
Résumé In the present study we investigated the biogeography of macrozooplankton and fish biomass in the Bay of Biscay. In this region, we defined six different landscapes based on the hydrogeographical characteristics observed in spring 2009. We then related landscape's characteristics and environmental parameters such as light attenuation depth and chlorophyll-a with macrozooplankton and fish acoustic biomass. Hydrodynamic structures together with coastal influences (river discharges, predation pressure and depth preference) and vertical thermohaline structure/mixing (feeding modes and ability to stay in preferred layers) appeared as the main factors determining the biological distribution. Besides, variance partitioning was used to assess the respective roles played by the hydrological environment, the geographical space and the biological environment alone, and their interactions. Results revealed that: (i) macrozooplankton and fish have a preference for different hydrogeographical landscapes; (ii) the association between hydrological conditions and geographical features, i.e. the spatial structure of the hydrological environment, plays a key role in the distribution of macrozooplankton; and (iii) prey-predator relationships have to be taken into account to provide a comprehensive characterization of habitat suitability.
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ISSN 1054-6006 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1109
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Auteur Ayon, P.; Swartzman, G.; Espinoza, P.; Bertrand, A.
Titre Long-term changes in zooplankton size distribution in the Peruvian Humboldt Current System : conditions favouring sardine or anchovy Type Article scientifique
Année 2011 Publication Revue Abrégée Marine Ecology. Progress Series
Volume 422 Numéro Pages 211-222
Mots-Clés abundance; anchovy; Current; dominance; energetics; Euphausiids; Feeding; Humboldt; Sardine; size; System; Zooplankton
Résumé Changes in the size distribution of zooplankton in the Humboldt Current System have been hypothesized to underlie observed changes in sardine and anchovy populations, the dominant pelagic fish species. To examine this hypothesis, the size distribution of over 15 000 zooplankton data samples collected since the 1960s was qualitatively determined. Dominance of each size group of zooplankton (small, medium and large) and of euphausiids was modelled using generalized additive models as a function of year, latitude, time of day, distance from the 200 m isobath (a surrogate for on-shelf versus off-shelf), sea surface temperature and salinity. The temporal (yr) pattern for euphausiid dominance was highly cross-correlated (i.e. was in phase) with the time series for estimated biomass of anchovy, and small zooplankton dominance with that for estimated sardine biomass. This supports the focal hypothesis based on feeding-energetic experiments, which showed energetic advantages to sardine filter feeding on smaller zooplankton and to anchovy bite feeding on larger copepods and euphausiids. Although euphausiids predominate offshore from the shelf break, anchovy biomass is generally highest on the shelf, suggesting a possible mismatch between anchovy feeding and euphausiid dominance. However, evidence concerning the offshore expansion of the anchovy range in cooler conditions, where both anchovy and euphausiids predominate, somewhat alleviates this apparent contradiction. A strong diel component to euphausiids and large zooplankton indicated diel migration for these zooplankton groups. That anchovy will preferentially eat euphausiids when they are more available (i.e. during the night and offshore) is supported by anchovy diet data.
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ISSN 0171-8630 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 117
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Auteur Pagano, M.; Sagarra, P.-B.; Champalbert, G.; Bouvy, M.; Dupuy, C.; Thomas, Y.; Charpy, L.
Titre Metazooplankton communities in the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia): Spatiotemporal variations and trophic relationships Type Article scientifique
Année 2012 Publication Revue Abrégée Marine Pollution Bulletin
Volume 65 Numéro 10–12 Pages 538-548
Mots-Clés Atoll lagoon; French Polynesia; Metazooplankton; Spatio-temporal patterns; Trophic relationships; pearl oyster
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ISSN 0025-326x ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 693
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Auteur Amélineau, F.; Grémillet, D.; Bonnet, D.; Bot, T.L.; Fort, J.
Titre Where to Forage in the Absence of Sea Ice? Bathymetry As a Key Factor for an Arctic Seabird Type Article scientifique
Année 2016 Publication Revue Abrégée Plos One
Volume 11 Numéro 7 Pages e0157764
Mots-Clés Birds; Copepods; Foraging; Predation; Seabirds; Sea ice; Trophic interactions; Zooplankton
Résumé The earth is warming at an alarming rate, especially in the Arctic, where a marked decline in sea ice cover may have far-ranging consequences for endemic species. Little auks, endemic Arctic seabirds, are key bioindicators as they forage in the marginal ice zone and feed preferentially on lipid-rich Arctic copepods and ice-associated amphipods sensitive to the consequences of global warming. We tested how little auks cope with an ice-free foraging environment during the breeding season. To this end, we took advantage of natural variation in sea ice concentration along the east coast of Greenland. We compared foraging and diving behaviour, chick diet and growth and adult body condition between two years, in the presence versus nearby absence of sea ice in the vicinity of their breeding site. Moreover, we sampled zooplankton at sea when sea ice was absent to evaluate prey location and little auk dietary preferences. Little auks foraged in the same areas both years, irrespective of sea ice presence/concentration, and targeted the shelf break and the continental shelf. We confirmed that breeding little auks showed a clear preference for larger copepod species to feed their chick, but caught smaller copepods and nearly no ice-associated amphipod when sea ice was absent. Nevertheless, these dietary changes had no impact on chick growth and adult body condition. Our findings demonstrate the importance of bathymetry for profitable little auk foraging, whatever the sea-ice conditions. Our investigations, along with recent studies, also confirm more flexibility than previously predicted for this key species in a warming Arctic.
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ISSN 1932-6203 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1592
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Auteur Dupuy, C.; Pagano, M.; Got, P.; Domaizon, I.; Chappuis, A.; Marchessaux, G.; Bouvy, M.
Titre Trophic relationships between metazooplankton communities and their plankton food sources in the Iles Eparses (Western Indian Ocean) Type Article scientifique
Année 2016 Publication Revue Abrégée Marine Environmental Research
Volume 116 Numéro Pages 18-31
Mots-Clés feeding ecology; grazing effect; Iles Eparses; Mayotte; Metazooplankton; spatial distribution
Résumé Coral reef and atoll lagoons are among the most diversified marine ecosystems but also the most affected by the combined effects of climate change and human activities. The Iles Eparses (Scattered Islands) in the Western Indian Ocean have been little affected by human pressure and can be considered to be “pristine” ecosystems. Metazooplankton plays a major role in the functioning and productivity of aquatic ecosystems, and this study was undertaken: (i) to determine the spatial abundance, distribution and species composition of metazooplankton, (ii) to assess the effect of metazooplankton grazing on pico- and nanophytoplankton and (iii) to analyze the trophic positions of metazooplankton by using the stable isotope signatures of a wide variety of taxa and particulate organic matter from the Iles Eparses and Mayotte. Tromelin Island (which is not located in the Mozambique Channel) had the lowest metazooplankton abundance with no cyanobacteria Trichodesmium spp. or mollusks (pteropods) presence, and with δ15N signatures of organisms that were higher than for the islands in the Mozambique Channel. Trichodesmium spp. was found in the Mozambique Channel and the plankton food web was probably based preferentially on these cyanobacteria with lower δ15N signatures indicating direct or indirect trophic transfer of diazotrophic nitrogen to metazooplankton. Three of the islands were distinct: Europa had the highest proportion of copepods, with oithonids being dominant, which is typical of rich mangrove systems, while Juan de Nova and Mayotte seemed to be the sites most affected by human activity with a high abundance of appendicularians and distinct particulate organic matter ∂13C signatures. Grazing experiments showed that food could be a limiting factor for metazooplankton in the Iles Eparses. However, the effect of metazooplankton grazing on phytoplankton appeared to be very low (0.01–2.32% of the total phytoplankton per day).
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Langue (up) Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0141-1136 ISBN Médium
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Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1496
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