|   | 
Détails
   web
Enregistrements
Auteur Jose, Y.S.; Aumont, O.; Machu, E.; Penven, P.; Moloney, C.L.; Maury, O.
Titre Influence of mesoscale eddies on biological production in the Mozambique Channel : several contrasted examples from a coupled ocean-biogeochemistry model Type Article scientifique
Année 2014 Publication Revue Abrégée Deep-Sea Research Part II.Topical Studies in Oceanography
Volume 100 Numéro No spécial Pages 79-93
Mots-Clés Chlorophyll; Cyclonic and anticyclonic eddies; Mozambique Channel; Nutrients; Ocean physical-biogeochemical coupling
Résumé The impact of mesoscale activity on phytoplankton and nutrient distribution in the Mozambique Channel was simulated by coupling a biogeochemical model (PISCES) with a regional oceanic model (ROMS). Examples of the effects of eddies on the biogeochemistry of the Mozambique Channel are presented to illustrate the complexity of the system. In the model, several cyclonic eddies were found with low concentrations of chlorophyll at their cores, which contrasts with previous studies in the open ocean. In addition, several anticyclonic eddies were simulated with high concentrations of chlorophyll at their cores. Phytoplankton growth within these mesoscale features (both cyclonic and anticyclonic eddies) occurred in response to nutrient injection into the euphotic zone by advection, and subsequent retention of surrounding nutrient-rich waters within eddies. Offshore nutrient distributions depended strongly on lateral advection of nutrient-rich water from the coastal regions, induced by eddy interaction with the shelf. The environmental conditions at the locations where eddies were generated had an important effect on nutrient concentrations within these structures.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur Barlow, R.; Marsac, F.; Ternon, J.-F.; Roberts, M.
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 364
Lien permanent pour cet enregistrement
 

 
Auteur Lezama-Ochoa, A.; Irigoien, X.; Chaigneau, A.; Quiroz, Z.; Lebourges Dhaussy, A.; Bertrand, A.
Titre Acoustic reveal the presence of Macrozooplankton biocline in the Bay of Biscay in response to hydrological conditions and predator-prey relationships Type Article scientifique
Année 2014 Publication Revue Abrégée PLoS One
Volume 9 Numéro 2 Pages
Mots-Clés
Résumé Bifrequency acoustic data, hydrological measurements and satellite data were used to study the vertical distribution of

macrozooplankton in the Bay of Biscay in relation to the hydrological conditions and fish distribution during spring 2009.

The most noticeable result was the observation of a &8216;biocline&8217; during the day i.e., the interface where zooplankton biomass

changes more rapidly with depth than it does in the layers above or below. The biocline separated the surface layer, almost

devoid of macrozooplankton, from the macrozooplankton-rich deeper layers. It is a specific vertical feature which ties in

with the classic diel vertical migration pattern. Spatiotemporal correlations between macrozooplankton and environmental

variables (photic depth, thermohaline vertical structure, stratification index and chlorophyll-a) indicate that no single factor

explains the macrozooplankton vertical distribution. Rather a set of factors, the respective influence of which varies from

region to region depending on the habitat characteristics and the progress of the spring stratification, jointly influence the

distribution. In this context, the macrozooplankton biocline is potentially a biophysical response to the search for a

particular depth range where light attenuation, thermohaline vertical structure and stratification conditions together

provide a suitable alternative to the need for expending energy in reaching deeper water without the risk of being eaten.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue eng Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 365
Lien permanent pour cet enregistrement
 

 
Auteur Lefevre, S.; Domenici, P.; McKenzie, D.J.
Titre Swimming in air-breathing fishes Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Fish Biology
Volume 84 Numéro 3 Pages 661-681
Mots-Clés acid-base; aerobic metabolism; amia-calva; bimodal respiration; dicentrarchus-labrax; european sea-bass; exercise; exhaustive exercise; gar lepisosteus-platyrhincus; megalops-cyprinoides; pacific; partitioning; rainbow-trout; recovery; respiratory; tarpon; trout oncorhynchus-mykiss
Résumé Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 0022-1112 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 877
Lien permanent pour cet enregistrement
 

 
Auteur LAGABRIELLE, E.; CROCHELET, E.; ANDRELLO, M.; SCHILL, S.R.; ARNAUD-HAOND, S.; ALLONCLE, N.; PONGE, B.
Titre Connecting MPAs – eight challenges for science and management Type Article scientifique
Année 2014 Publication Revue Abrégée Aquatic Conservation-marine And Freshwater Ecosystems
Volume 24 Numéro Pages 94-110
Mots-Clés coastal; conservation evaluation; Fishing; Marine Protected Areas; ocean; spatial modelling
Résumé Connectivity is a crucial process underpinning the persistence, recovery, and productivity of marine ecosystems. The Convention on Biological Diversity, through the Aichi Target 11, has set the ambitious objective of implementing a ‘well connected system of protected areas’ by 2020. This paper identifies eight challenges toward the integration of connectivity into MPA network management and planning. A summary table lists the main recommendations in terms of method, tool, advice, or action to address each of these challenges. Authors belong to a science–management continuum including researchers, international NGO officers, and national MPA agency members. Three knowledge challenges are addressed: selecting and integrating connectivity measurement metrics; assessing the accuracy and uncertainty of connectivity measurements; and communicating and visualizing connectivity measurements. Three management challenges are described: integrating connectivity into the planning and management of MPA networks; setting quantitative connectivity targets; and implementing connectivity-based management across scales and marine jurisdictions. Finally, two paths toward a better integration of connectivity science with MPA management are proposed: setting management-driven priorities for connectivity research, bridging connectivity science, and MPA network management. There is no single method to integrate connectivity into marine spatial planning. Rather, an array of methods can be assembled according to the MPA network objectives, budget, available skills, data, and timeframe. Overall, setting up ‘boundary organizations’ should be promoted to organize complex cross-disciplinary, cross-sectoral and cross-jurisdiction interactions that are needed between scientists, managers, stakeholders and decision-makers to make informed decision regarding connectivity-based MPA planning and management.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 1052-7613 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1133
Lien permanent pour cet enregistrement
 

 
Auteur Marsac, F.; Barlow, R.; Ternon, J.-F.; Ménard, F.; Roberts, M.
Titre Ecosystem functioning in the Mozambique Channel : synthesis and future research Type Article scientifique
Année 2014 Publication Revue Abrégée Deep-Sea Research Part II.Topical Studies in Oceanography
Volume 100 Numéro No spécial Pages 212-220
Mots-Clés Bio-physical coupling; Ecosystem approach; Mesoscale circulation; Mozambique Channel
Résumé The MESOBIO programme investigated mesoscale dynamics using an integrated ecosystem approach, linking physical and biogeochemical processes with different trophic levels. Observation and modeling were used in combination to explain the main processes occurring in the mesoscale eddy field. The particular shape of the Mozambique Channel, composed of two basins interconnected through a narrow zone, favours the generation of mesoscale eddies and increases the opportunity for eddy-shelf interactions. Phytoplankton abundance peaked in areas of nutrient enrichment that are often found in the core of cyclonic eddies, as well as on the continental shelf. Grazers in zooplankton communities exhibited high biovolume in cyclonic eddies, but their abundance was lower in fronts and divergence zones, with lowest biovolume in anticyclones. Biovolume was highest at shelf stations, but very variable and similar to phytoplankton. Age of eddies, their subsequent maturation stage and the dynamics of the eddy field played a major role effecting zooplankton abundance. Micronekton presented abundance patterns coherent with zooplankton distribution, however this was only demonstrated by acoustic methods, whereas mid-water trawl collection and predators stomach contents (predators being used as biological samplers) did not reveal significant relationships with mesoscale features. For upper trophic levels, the average density of foraging seabirds was lowest in anticyclones, highest in cyclones and at intermediate levels in divergence, shelf and frontal zones. However, multifaceted behavioral responses were observed in such a highly variable environment. Swordfish was clearly associated with divergence zones, and to a lesser extent with fronts, suggesting that the higher density in divergences was related to the presence of its main prey, essentially large squids. Although tunas tended to be more abundant in areas with weak geostrophic currents, their relationship to mesoscale features was not straightforward as adult tunas caught by longline have the ability to explore different foraging habitats over a broad range of depths. Several suggestions for advancing eddy-related research from the current state of knowledge are proposed in the second part of the paper.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur Barlow, R.; Marsac, F.; Ternon, J.-F.; Roberts, M.
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection (down) Numéro de collection Edition
ISSN 0967-0645 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 366
Lien permanent pour cet enregistrement