|   | 
Détails
   web
Enregistrements
Auteur Leruste, A.; Villeger, S.; Malet, N.; De Wit, R.; Bec, B.
Titre (up) Complementarity of the multidimensional functional and the taxonomic approaches to study phytoplankton communities in three Mediterranean coastal lagoons of different trophic status Type Article scientifique
Année 2018 Publication Revue Abrégée Hydrobiologia
Volume 815 Numéro 1 Pages 207-227
Mots-Clés classification; Classification; disturbance; diversity; ecology; Functional entity; Functional traits; lake phytoplankton; marine-phytoplankton; patterns; size; synechococcus; Taxonomic diversity; traits
Résumé We used the individual-based multidimensional functional diversity and the taxonomic approaches in a complementary way to describe phytoplankton communities in three coastal lagoons with different eutrophication status in the South of France. We sampled communities during three seasons, i.e., in autumn, spring, and summer. Using classical taxonomy, 107 taxa/morphotypes were identified in the nine communities. The individual-based functional approach allowed grouping these individuals into 20 functional entities according to their values for 5 traits related to trophic adaptations (cell size, mobility, trophic regime, coloniality, and pelagic/benthic life). Some species (e.g., Prorocentrum micans) emerged in multiple functional entities, showing the importance to consider intraspecific variability. The functional description of phytoplankton communities better reflected the hydrological functioning and the different eutrophication status of the lagoons than the taxonomic approach. Specific functional adaptations were identified in the nine communities. For example, phytoplankton organisms with heterotrophic and potentially mixotrophic abilities occurred when the availability of inorganic nutrient decreased, or when organic matter and small preys were potentially the main nutrient resources. The limitation has also favored small cells highly competitive for nutrients. Using functional indices together with taxonomic description has also helped revealing important aspects of community assembly, such as competitive exclusion in summer.
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 Numéro de collection Edition
ISSN 0018-8158 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 2322
Lien permanent pour cet enregistrement
 

 
Auteur Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J.
Titre (up) Complex Effects of Ecosystem Engineer Loss on Benthic Ecosystem Response to Detrital Macroalgae Type Article scientifique
Année 2013 Publication Revue Abrégée PLoS One
Volume 8 Numéro 6 Pages
Mots-Clés Community structure; assemblages; biodiversity; carbon flow; diversity; experiment; field; impact; marine-sediments; species richness; stability
Résumé Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies the response to macroalgal detrital enrichment of sediment biogeochemical properties, microphytobenthos and macrofauna assemblages. A field manipulative experiment was done on an intertidal sandflat (Oosterschelde estuary, The Netherlands). Lugworms were deliberately excluded from 1x m sediment plots and different amounts of detrital Ulva (0, 200 or 600 g Wet Weight) were added twice. Sediment biogeochemistry changes were evaluated through benthic respiration, sediment organic carbon content and porewater inorganic carbon as well as detrital macroalgae remaining in the sediment one month after enrichment. Microalgal biomass and macrofauna composition were measured at the same time. Macroalgal carbon mineralization and transfer to the benthic consumers were also investigated during decomposition at low enrichment level (200 g WW). The interaction between lugworm exclusion and detrital enrichment did not modify sediment organic carbon or benthic respiration. Weak but significant changes were instead found for porewater inorganic carbon and microalgal biomass. Lugworm exclusion caused an increase of porewater carbon and a decrease of microalgal biomass, while detrital enrichment drove these values back to values typical of lugworm-dominated sediments. Lugworm exclusion also decreased the amount of macroalgae remaining into the sediment and accelerated detrital carbon mineralization and CO2 release to the water column. Eventually, the interaction between lugworm exclusion and detrital enrichment affected macrofauna abundance and diversity, which collapsed at high level of enrichment only when the lugworms were present. This study reveals that in nature the role of this ecosystem engineer may be variable and sometimes have no or even negative effects on stability, conversely to what it should be expected based on current research knowledge.
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 Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 513
Lien permanent pour cet enregistrement
 

 
Auteur Tribot, A.-S.; Carabeux, Q.; Deter, J.; Claverie, T.; Villeger, S.; Mouquet, N.
Titre (up) Confronting species aesthetics with ecological functions in coral reef fish Type Article scientifique
Année 2018 Publication Revue Abrégée Sci Rep
Volume 8 Numéro Pages 11733
Mots-Clés appeal; diversity; ecosystem services; experience
Résumé The biodiversity crisis has spurred scientists to assess all facets of biodiversity so that stakeholders can establish protection programs. However, species that are perceived as beautiful receive more attention than less attractive species. This dynamic could have tremendous consequences on people's willingness to preserve biodiversity. Coral reefs might be particularly affected by this issue as they are key ecosystems that provide many services, such as aesthetic and cultural benefits attracting millions of tourists each year. Here we show the results of an online photographic questionnaire completed by 8,000 participants whereby preferences were assessed for a set of 116 reef fishes. Based on these preferences, we compared the functional richness, i.e. the amount of functional space filled, by groups of fishes based on their perceived attractiveness. We present evidence indicating that the least attractive coral reef fishes have a much higher functional richness than the most attractive species. Our results highlight the extent to which species aesthetic values' may be disconnected from their ecological values and could be misleading for conservation purposes. There is thus an urgent need to increase the attention of scientists and the general public towards less attractive species to better appreciate and protect the species that crucially support functional diversity in endangered ecosystems.
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 Numéro de collection Edition
ISSN 2045-2322 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 2386
Lien permanent pour cet enregistrement
 

 
Auteur Goni-Urriza, M.; Moussard, H.; Lafabrie, H.; Carré, C.; Bouvy, M.; Sakka Hlaili, A.; Pringault, O.
Titre (up) Consequences of contamination on the interactions between phytoplankton and bacterioplankton Type Article scientifique
Année 2018 Publication Revue Abrégée Chemosphere
Volume 195 Numéro Pages 212-222
Mots-Clés bizerte lagoon; bacterial communities; polycyclic aromatic-hydrocarbons; surface sediments; functional diversity; ecosystem; sediment resuspension; coastal lagoon; nutrient enrichment; tropical lagoon
Résumé Sediment resuspension can provoke strong water enrichment in nutrients, contaminants, and microorganisms. Microcosm incubations were performed in triplicate for 96 h, with lagoon and offshore waters incubated either with sediment elutriate or with an artificial mixture of contaminants issued from sediment resuspension. Sediment elutriate provoked a strong increase in microbial biomass, with little effects on the phytoplankton and bacterioplankton community structures. Among the pool of contaminants released, few were clearly identified as structuring factors of phytoplanktdn and bacterioplankton communities, namely simazine, Cu, Sn, Ni, and Cr. Effects were more pronounced in the offshore waters, suggesting a relative tolerance of the lagoon microbial communities to contamination. The impacts of contamination on the microbial community structure were direct or indirect, depending on the nature and the strength of the interactions between phytoplankton and bacterioplankton. (C) 2017 Elsevier Ltd. All rights reserved.
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 Numéro de collection Edition
ISSN 0045-6535 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 2265
Lien permanent pour cet enregistrement
 

 
Auteur Bouvier, T.; Venail, P.; Pommier, T.; Bouvier, C.; Barbera, C.; Mouquet, N.
Titre (up) Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities Type Article scientifique
Année 2012 Publication Revue Abrégée PLoS One
Volume 7 Numéro 6 Pages
Mots-Clés 16s ribosomal-rna; bacterial communities; biodiversity; dispersal; fresh-water; gradient gel-electrophoresis; metacommunities; predictability; productivity; stability
Résumé The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local “physiological insurance” may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations.
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 Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 499
Lien permanent pour cet enregistrement