bascule de visibilité Search & Display Options

Tout Sélectionner    Désélectionner
 |   | 
Détails
   print
  Enregistrements Liens
Auteur Bouvy, M.; Got, P.; Domaizon, I.; Pagano, M.; Leboulanger, C.; Bouvier, C.; Carré, C.; Roques, C.; Dupuy, C. url  doi
openurl 
  Titre Plankton communities in the five Iles Eparses (Western Indian Ocean) considered to be pristine ecosystems Type Article scientifique
  Année (down) 2016 Publication Revue Abrégée Acta Oecologica  
  Volume Numéro Pages 9-20  
  Mots-Clés Distribution; Enrichment experiment; Iles Eparses; Islands; Microorganisms; Mozambique Channel; Nutrient limitation  
  Résumé Coral reef environments are generally recognized as being the most threatened of marine ecosystems. However, it is extremely difficult to distinguish the effects of climate change from other forcing factors, mainly because it is difficult to study ecosystems that are isolated from human pressure. The five Iles Eparses (Scattered Islands) are located in the Western Indian Ocean (WIO) and can be considered to be “pristine” ecosystems not subject to anthropogenic pressure. This study characterized their plankton assemblages for the first time, by determining the abundances of microbial (virus, bacteria, heterotrophic protists and phytoplankton) and metazooplankton communities in various lagoon and ocean sites around each island. The Europa lagoon has extensive, productive mangrove forests, which have the highest nutrient concentrations (nitrogen forms, dissolved organic carbon) and whose microbial communities present a peculiar structure and functioning. By means of bioassay experiments, we observed that bacterial production and growth rates are higher in Europa than those reported for the other islands. Tromelin, which lies outside the Mozambique Channel, had the lowest biological productivity, nutrient concentrations, and bacterial growth rates. Multivariate analysis indicated that distinct microbial assemblages occur in association to varying nutrient concentrations. Molecular fingerprinting showed clear discrimination of the structure of the archaea, bacteria and eukaryotes community between the sites. Our results suggest that the geographical distance can influence the diversity of dominant microbial taxa in the WIO.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Îles Éparses (French Scattered Islands, SW Indian Ocean) as reference ecosystems for environmental research. Titre de collection Abrégé  
  Volume de collection 72 Numéro de collection Edition  
  ISSN 1146-609x ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1494  
Lien permanent pour cet enregistrement
 

 
Auteur Dupuy, C.; Pagano, M.; Got, P.; Domaizon, I.; Chappuis, A.; Marchessaux, G.; Bouvy, M. url  doi
openurl 
  Titre Trophic relationships between metazooplankton communities and their plankton food sources in the Iles Eparses (Western Indian Ocean) Type Article scientifique
  Année (down) 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).  
  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 Numéro de collection Edition  
  ISSN 0141-1136 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1496  
Lien permanent pour cet enregistrement
 

 
Auteur Boyd, C.; Castillo, R.; Hunt, G.L.; Punt, A.E.; VanBlaricom, G.R.; Weimerskirch, H.; Bertrand, S. url  doi
openurl 
  Titre Predictive modelling of habitat selection by marine predators with respect to the abundance and depth distribution of pelagic prey Type Article scientifique
  Année (down) 2015 Publication Revue Abrégée J Anim Ecol  
  Volume 84 Numéro 6 Pages 1575-1588  
  Mots-Clés central place foragers; Foraging ecology; habitat use; Humboldt Current system; predator–prey interactions; spatial distribution  
  Résumé * Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. * We analysed contemporaneous data on the diving locations of two seabird species, the shallow-diving Peruvian Booby (Sula variegata) and deeper diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique data set, we developed resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper water column. * For both species, we show that the probability of diving behaviour is mostly explained by the distribution of prey at shallow depths. While the probability of diving behaviour increases sharply with prey abundance at relatively low levels of abundance, support for including abundance in addition to the depth distribution of prey is weak, suggesting that prey abundance was not a major factor determining the location of diving behaviour during the study period. * The study thus highlights the importance of the depth distribution of prey for two species of seabird with different diving capabilities. The results complement previous research that points towards the importance of oceanographic processes that enhance the accessibility of prey to seabirds. The implications are that locations where prey is predictably found at accessible depths may be more important for surface foragers, such as seabirds, than locations where prey is predictably abundant. * Analysis of the relative importance of abundance and accessibility is essential for the design and evaluation of effective management responses to reduced prey availability for seabirds and other top predators in marine systems.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue en Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1365-2656 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1349  
Lien permanent pour cet enregistrement
 

 
Auteur Genovesi, B.; Berrebi, P.; Nagai, S.; Reynaud, N.; Wang, J.; Masseret, E. url  doi
openurl 
  Titre Geographic structure evidenced in the toxic dinoflagellate Alexandrium pacificum Litaker (A. catenella – group IV (Whedon & Kofoid) Balech) along Japanese and Chinese coastal waters Type Article scientifique
  Année (down) 2015 Publication Revue Abrégée Marine Pollution Bulletin  
  Volume 98 Numéro 1–2 Pages 95-105  
  Mots-Clés Alexandrium pacificum (A. catenella – group IV); Harmful algal blooms; Invasive species distribution; Microsatellites markers; Temperate Asian coasts; Toxic dinoflagellate  
  Résumé Abstract

The intra-specific diversity and genetic structure within the Alexandrium pacificum Litaker (A. catenella – Group IV) populations along the Temperate Asian coasts, were studied among individuals isolated from Japan to China. The UPGMA dendrogram and FCA revealed the existence of 3 clusters. Assignment analysis suggested the occurrence of gene flows between the Japanese Pacific coast (cluster-1) and the Chinese Zhejiang coast (cluster-2). Human transportations are suspected to explain the lack of genetic difference between several pairs of distant Japanese samples, hardly explained by a natural dispersal mechanism. The genetic isolation of the population established in the Sea of Japan (cluster-3) suggested the existence of a strong ecological and geographical barrier. Along the Pacific coasts, the South–North current allows limited exchanges between Chinese and Japanese populations. The relationships between Temperate Asian and Mediterranean individuals suggested different scenario of large-scale dispersal mechanisms.
 
  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 Numéro de collection Edition  
  ISSN 0025-326x ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1352  
Lien permanent pour cet enregistrement
 

 
Auteur Descombes, P.; Wisz, M.S.; Leprieur, F.; Parravicini, V.; Heine, C.; Olsen, S.M.; Swingedouw, D.; Kulbicki, M.; Mouillot, D.; Pellissier, L. url  doi
openurl 
  Titre Forecasted coral reef decline in marine biodiversity hotspots under climate change Type Article scientifique
  Année (down) 2015 Publication Revue Abrégée Glob Change Biol  
  Volume 21 Numéro 7 Pages 2479-2487  
  Mots-Clés fish; fossil; Sea surface temperature; specialists; species distribution model; species richness  
  Résumé Coral bleaching events threaten coral reef habitats globally and cause severe declines of local biodiversity and productivity. Related to high sea surface temperatures (SST), bleaching events are expected to increase as a consequence of future global warming. However, response to climate change is still uncertain as future low-latitude climatic conditions have no present-day analogue. Sea surface temperatures during the Eocene epoch were warmer than forecasted changes for the coming century, and distributions of corals during the Eocene may help to inform models forecasting the future of coral reefs. We coupled contemporary and Eocene coral occurrences with information on their respective climatic conditions to model the thermal niche of coral reefs and its potential response to projected climate change. We found that under the RCP8.5 climate change scenario, the global suitability for coral reefs may increase up to 16% by 2100, mostly due to improved suitability of higher latitudes. In contrast, in its current range, coral reef suitability may decrease up to 46% by 2100. Reduction in thermal suitability will be most severe in biodiversity hotspots, especially in the Indo-Australian Archipelago. Our results suggest that many contemporary hotspots for coral reefs, including those that have been refugia in the past, spatially mismatch with future suitable areas for coral reefs posing challenges to conservation actions under climate change.  
  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 Numéro de collection Edition  
  ISSN 1365-2486 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1362  
Lien permanent pour cet enregistrement
Tout Sélectionner    Désélectionner
 |   | 
Détails
   print

Save Citations:
Export Records: