bascule de visibilité Search & Display Options

Tout Sélectionner    Désélectionner
 |   | 
Détails
   print
  Enregistrements Liens
Auteur Mostajir, B.; Amblard, C.; Buffan-Dubau, E.; De Wit, R.; Lensi, R.; Sime-Ngando, T. url  isbn
openurl 
  Titre Microbial Food Webs in Aquatic and Terrestrial Ecosystems Type Chapitre de livre
  Année 2015 Publication Revue Abrégée  
  Volume Numéro Pages 485-509  
  Mots-Clés Biodiversity; Biogeochemical cycles; Ecological interactions; Microbial Ecology; Microbial food webs; Microbial loop  
  Résumé In microbial food webs, different types of interactions occur between microorganisms themselves and with meio- and macroorganisms. After an historical and general introduction, the biological components of the microbial food webs in the pelagic and benthic marine and lake ecosystems, as well as in the terrestrial ecosystems, are presented. The functioning of the microbial food webs in different ecosystems is illustrated and explained, including the trophic pathways and transfer of matter from microbial food webs toward meio- and macroorganisms of the superior trophic levels, the nutrient recycling in the aquatic environments, and the decomposition of organic matter in soils. Finally, the factors regulating microbial food webs, primarily “top-down” and “bottom-up” controls, are described with a special focus on the role of viruses in the aquatic microbial food webs.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Springer Netherlands Lieu de Publication Éditeur Bertrand, J.-C.; Caumette, P.; Lebaron, P.; Matheron, R.; Normand, P.; Sime-Ngando, T.  
  Langue en Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé (down) Environmental Microbiology: Fundamentals and Applications  
  Volume de collection Numéro de collection Edition  
  ISSN ISBN 978-94-017-9117-5 978-94-017-9118-2 Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1394  
Lien permanent pour cet enregistrement
 

 
Auteur Leblad, B.R.; Amnhir, R.; Reqia, S.; Sitel, F.; Daoudi, M.; Marhraoui, M.; Abdellah, M.K.O.; Veron, B.; Er-Raioui, H.; Laabir, M. doi  openurl
  Titre Seasonal variations of phytoplankton assemblages in relation to environmental factors in Mediterranean coastal waters of Morocco, a focus on HABs species Type Article scientifique
  Année 2020 Publication Revue Abrégée Harmful Algae  
  Volume 96 Numéro Pages 101819  
  Mots-Clés bay; bizerte lagoon; climate-change; domoic acid; Environmental factors; gymnodinium-catenatum; HABs; harmful algal blooms; Phytoplankton diversity; pseudo-nitzschia; psp toxins; shellfish; SW Mediterranean; temperature; Toxins  
  Résumé Studies on phytoplankton and in particular Harmful Algal Blooms (HABs) species in southern Mediterranean waters are scarce. We performed from April 2008 to June 2009 weekly investigations on microphytoplankton community structure and abundance in two contrasted marine ecosystems located in the western Moroccan Mediterranean coast, M'diq Bay and Oued Laou Estuary. Simultaneously, we measured the main physico-chemical parameters. Globally, the two studied areas showed comparable values of the assessed abiotic environmental factors. Temperature and salinity followed seasonal variation with values ranging from 13.5 degrees C to 21.4 degrees C and 31 to 36.8, respectively. Average nutrient values in surface water ranged from 0.7 to 45.76 mu M for dissolved inorganic nitrogen, 0.02-2.10 mu M for PO4 and 0.23-17.46 mu M for SiO4 in the study areas. A total of 92 taxa belonging to 8 taxonomic classes were found. The highest number of microphytoplankton abundance reached 1.2 x 10(6) cells L-1 with diatoms being the most abundant taxa. Factorial Discriminant Analysis (FDA) and Spearman correlation test showed a significant seasonal discrimination of dominant microphytoplankton species. These micro-organisms were associated with different environmental variables, in particular temperature and salinity. Numerous HABs species were encountered regularly along the year. Although Dinophysis species and Prorocentrum lima were present in both sites, no Lipophilic Shellfish Poisoning was detected for the analyzed bivalve mollusks. Domoic acid (DA), produced by toxic species of Pseudo-nitzschia was found with concentrations up to 18 mu g DA g(-1) in the smooth clam Callista chione. Data showed that the observed persistent and dramatic Paralytic Shellfish Poisoning (PSP) intoxication of mollusks resulted probably of Gymnodinium catenatum proliferations in both studied areas. Contrary to C. chione, the cockle Achanthocardia tuberculatum showed a permanent and extremely high toxicity level during the 15 months survey with up to 7545 mu g Equivalent Saxitoxin kg(-1) flesh (ten times higher than the sanitary threshold of 800 tg eqSTX Kg(-1) flesh). The present work highlights for the first time the dynamic of microphytoplankton including HABs species and their associated toxin accumulation in the commercially exploited shellfish in the southern western Mediterranean waters of Morocco. Furthermore, the acquired data will help us to improve the monitoring of HABs species and related toxins in these coastal marine systems.  
  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 (down)  
  Volume de collection Numéro de collection Edition  
  ISSN 1568-9883 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000541912700003 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2820  
Lien permanent pour cet enregistrement
 

 
Auteur Soares, A.; Lira, A.S.; Gonzalez, J.G.; Eduardo Nole, L.; Lucena-Fredou, F.; Le Loc'h, F.; Ferreira, B.P.; Fredou, T. doi  openurl
  Titre Feeding habits and population aspects of the spotted goatfish, Pseudupeneus maculatus (Perciformes: Mullidae), on the continental shelf of northeast Brazil Type Article scientifique
  Année 2020 Publication Revue Abrégée Sci. Mar.  
  Volume 84 Numéro 2 Pages 119-131  
  Mots-Clés biodiversity; biology; Brazil; coast; cross-shelf; diet composition; distribution patterns; dynamics; ecology; island; reef fishes; stable isotopes; stomach content analysis; strategy; teleostei  
  Résumé This study provides information about the feeding habits, population aspects and spatial distribution of the spotted goatfish, Pseudupeneus maculatus, along the coast of the tropical Brazilian continental shelf. Distribution patterns are described using length frequencies and catch rates. Stable isotope ratios of carbon (delta C-13) and nitrogen (delta N-15), along with stomach contents, were analysed to determine the diet of the spotted goatfish. Multivariate analysis and numerical indicators of the diet, such as numerical frequency. frequency of occurrence and weight percentage, were computed to evaluate the diet composition. The mean trophic position was defined using both stable isotope ratios and stomach content analysis. The length at first maturity for the species was determined as 13.7 cm. A slight pattern in size distribution was observed, with mean size increasing with depth along the shelf. The diet was mainly composed of crustaceans, teleosts and Polychaeta. No clear dietary difference was found between habitat types, water depth or latitude. Both trophic positions estimated by stable isotopes and stomach contents analysis ranged between levels 3 and 4. P. maculatus was found to be feeding on many rare and infrequent prey items, classifying it as a generalist zoobenthivorous predator, probably due to its efficient search strategy.  
  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 (down)  
  Volume de collection Numéro de collection Edition  
  ISSN 0214-8358 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000539067100006 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2825  
Lien permanent pour cet enregistrement
 

 
Auteur Mouton, T.L.; Matheson, F.E.; Stephenson, F.; Champion, P.D.; Wadhwa, S.; Hamer, M.P.; Catlin, A.; Riis, T. doi  openurl
  Titre Environmental filtering of native and non-native stream macrophyte assemblages by habitat disturbances in an agricultural landscape Type Article scientifique
  Année 2019 Publication Revue Abrégée Sci. Total Environ.  
  Volume 659 Numéro Pages 1370-1381  
  Mots-Clés Agricultural impacts; classification; ecological impacts; eutrophication; Functional diversity; functional diversity measures; Functional traits; land-use; management; metaanalysis; Non-native flora; restoration; RLQ and fourth-corner analyses; species traits; trait responses  
  Résumé Understanding how inter-specific variation in functional traits affects native and non-native species responses to stream disturbances, is necessary to inform management strategies, providing tools for biomonitoring, conservation and restoration. This study used a functional trait approach to characterise the responses of macrophyte assemblages to reach-scale disturbances (measured by lack of riparian shading, altered hydromorphology and eutrophication), from 97 wadeable stream sites in an agriculturally impacted region of New Zealand. To determine whether macrophyte assemblages differed due to disturbances, we examined multidimensional assemblage functional structure in relation to eleven functional traits and further related two functional diversity indices (entropy and originality) to disturbances. Macrophyte assemblages showed distinct patterns in response to disturbances, with riparian shading and hydromorphological conditions being the strongest variables shaping macrophyte functional structure. In the multidimensional space, most of the non-native species were associatedwith disturbed conditions. These species had traits allowing faster colonisation rates (higher number of reproductive organs and larger root-rhizome system) and superior competitive abilities for resources (tall and dense canopy, heterophylly and greater preferences for light and nitrogen). In addition, lack of riparian shading increased the abundance of functionally distinct species (i.e. entropy), and eutrophication resulted in the growth of functionally unique species (i.e. originality). We demonstrated that stream reach-scale habitat disturbances were associated to a dominance of more productive species, equating to a greater abundance of non-native species. This, can result in a displacement of native species, habitat alterations, and changes to higher trophic level assemblages. Our results suggests that reachscale management efforts such as the conservation and restoration of riparian vegetation that provides substantial shading and hydromorphologically diverse in-stream habitat, would have beneficial direct and indirect effects on ecosystem functioning, and contribute to the mitigation of land-use impacts. (C) 2018 Published by Elsevier B.V.  
  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 (down)  
  Volume de collection Numéro de collection Edition  
  ISSN 0048-9697 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2571  
Lien permanent pour cet enregistrement
 

 
Auteur Mante, C.; Kide, S.O.; Yao-Lafourcade, A.-F.; Mérigot, B. doi  openurl
  Titre Fitting the truncated negative binomial distribution to count data A comparison of estimators, with an application to groundfishes from the Mauritanian Exclusive Economic Zone Type Article scientifique
  Année 2016 Publication Revue Abrégée Environ. Ecol. Stat.  
  Volume 23 Numéro 3 Pages 359-385  
  Mots-Clés Birth-and-dead models; classification; curves; diversity; habitat; Log-series; Minimum Hellinger distance; Negative binomial; parametric models; population; series; Species abundance; species abundance distributions; zeros  
  Résumé Modeling empirical distributions of repeated counts with parametric probability distributions is a frequent problem when studying species abundance. One must choose a family of distributions which is flexible enough to take into account very diverse patterns and possess parameters with clear biological/ecological interpretations. The negative binomial distribution fulfills these criteria and was selected for modeling counts of marine fish and invertebrates. This distribution depends on a vector of parameters, and ranges from the Poisson distribution (when ) to Fisher's log-series, when . Moreover, these parameters have biological/ecological interpretations which are detailed in the literature and in this study. We compared three estimators of K, and the parameter of Fisher's log-series, following the work of Rao CR (Statistical ecology. Pennsylvania State University Press, University Park, 1971) on a three-parameter unstandardized variant of the negative binomial distribution. We further investigated the coherence underlying parameter values resulting from the different estimators, using both real count data collected in the Mauritanian Exclusive Economic Zone (MEEZ) during the period 1987-2010 and realistic simulations of these data. In the case of the MEEZ, we first built homogeneous lists of counts (replicates), by gathering observations of each species with respect to “typical environments” obtained by clustering the sampled stations. The best estimation of was generally obtained by penalized minimum Hellinger distance estimation. Interestingly, the parameters of most of the correctly sampled species seem compatible with the classical birth-and-dead model of population growth with immigration by Kendall (Biometrika 35:6-15, 1948).  
  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 (down)  
  Volume de collection Numéro de collection Edition  
  ISSN 1352-8505 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2067  
Lien permanent pour cet enregistrement
Tout Sélectionner    Désélectionner
 |   | 
Détails
   print

Save Citations:
Export Records: