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Auteur Misson, B.; Garnier, C.; Lauga, B.; Dang, D.H.; Ghiglione, J.-F.; Mullot, J.-U.; Duran, R.; Pringault, O.
Titre Chemical multi-contamination drives benthic prokaryotic diversity in the anthropized Toulon Bay Type Article scientifique
Année 2016 Publication Revue Abrégée Science of The Total Environment
Volume 556 Numéro Pages 319-329
Mots-Clés Marine sediment; Microbial ecotoxicology; Multi-contamination; Prokaryotic diversity
Résumé Investigating the impact of human activities on marine coastal ecosystems remains difficult because of the co-occurrence of numerous natural and human-induced gradients. Our aims were (i) to evaluate the links between the chemical environment as a whole and microbial diversity in the benthic compartment, and (ii) to compare the contributions of anthropogenic and natural chemical gradients to microbial diversity shifts. We studied surface sediments from 54 sampling sites in the semi-enclosed Toulon Bay (NW Mediterranean) exposed to high anthropogenic pressure. Previously published chemical data were completed by new measurements, resulting in an in depth geochemical characterization by 29 representative environmental variables. Bacterial and archaeal diversity was assessed by terminal restriction fragment length polymorphism profiling on a selection of samples distributed along chemical gradients. Multivariate statistical analyses explained from 45% to 80% of the spatial variation in microbial diversity, considering only the chemical variables. A selection of trace metals of anthropogenic origin appeared to be strong structural factors for both bacterial and archaeal communities. Bacterial terminal restriction fragment (T-RF) richness correlated strongly with both anthropogenic and natural chemical gradients, whereas archaeal T-RF richness demonstrated fewer links with chemical variables. No significant decrease in diversity was evidenced in relation to chemical contamination, suggesting a high adaptive potential of benthic microbial communities in Toulon Bay.
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ISSN 0048-9697 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1560
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Auteur Barberan, A.; Fernandez-Guerra, A.; Auguet, J.C.; Galand, P.E.; Casamayor, E.O.
Titre Phylogenetic ecology of widespread uncultured clades of the Kingdom Euryarchaeota Type Article scientifique
Année 2011 Publication Revue Abrégée Mol Ecol
Volume 20 Numéro 9 Pages 1988-1996
Mots-Clés 16S/genetics Sequence Analysis; Biodiversity Databases; dna; Genetic *Ecosystem Environment Euryarchaeota/*classification/*genetics Genes; Ribosomal; rRNA/*genetics Phylogeny RNA
Résumé Despite its widespread distribution and high levels of phylogenetic diversity, microbes are poorly understood creatures. We applied a phylogenetic ecology approach in the Kingdom Euryarchaeota (Archaea) to gain insight into the environmental distribution and evolutionary history of one of the most ubiquitous and largely unknown microbial groups. We compiled 16S rRNA gene sequences from our own sequence libraries and public genetic databases for two of the most widespread mesophilic Euryarchaeota clades, Lake Dagow Sediment (LDS) and Rice Cluster-V (RC-V). The inferred population history indicated that both groups have undergone specific nonrandom evolution within environments, with several noteworthy habitat transition events. Remarkably, the LDS and RC-V groups had enormous levels of genetic diversity when compared with other microbial groups, and proliferation of sequences within each single clade was accompanied by significant ecological differentiation. Additionally, the freshwater Euryarchaeota counterparts unexpectedly showed high phylogenetic diversity, possibly promoted by their environmental adaptability and the heterogeneous nature of freshwater ecosystems. The temporal phylogenetic diversification pattern of these freshwater Euryarchaeota was concentrated both in early times and recently, similarly to other much less diverse but deeply sampled archaeal groups, further stressing that their genetic diversity is a function of environment plasticity. For the vast majority of living beings on Earth (i.e. the uncultured microorganisms), how they differ in the genetic or physiological traits used to exploit the environmental resources is largely unknown. Inferring population history from 16S rRNA gene-based molecular phylogenies under an ecological perspective may shed light on the intriguing relationships between lineage, environment, evolution and diversity in the microbial world.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1305
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Auteur Strauß, A.; Guilhaumon, F.; Randrianiaina, R.D.; Valero, K.C.W.; Vences, M.; Glos, J.
Titre Opposing Patterns of Seasonal Change in Functional and Phylogenetic Diversity of Tadpole Assemblages Type Article scientifique
Année 2016 Publication Revue Abrégée Plos One
Volume 11 Numéro 3 Pages e0151744
Mots-Clés Animal phylogenetics; Ecological metrics; Frogs; Phylogenetics; Polynomials; Seasons; species diversity; Tadpoles
Résumé Assemblages that are exposed to recurring temporal environmental changes can show changes in their ecological properties. These can be expressed by differences in diversity and assembly rules. Both can be identified using two measures of diversity: functional (FD) and phylogenetic diversity (PD). Frog communities are understudied in this regard, especially during the tadpole life stage. We utilised tadpole assemblages from Madagascan rainforest streams to test predictions of seasonal changes on diversity and assemblage composition and on diversity measures. From the warm-wet to the cool-dry season, species richness (SR) of tadpole assemblages decreased. Also FD and PD decreased, but FD less and PD more than expected by chance. During the dry season, tadpole assemblages were characterised by functional redundancy (among assemblages—with increasing SR), high FD (compared to a null model), and low PD (phylogenetic clustering; compared to a null model). Although mutually contradictory at first glance, these results indicate competition as tadpole community assembly driving force. This is true during the limiting cool-dry season but not during the more suitable warm-wet season. We thereby show that assembly rules can strongly depend on season, that comparing FD and PD can reveal such forces, that FD and PD are not interchangeable, and that conclusions on assembly rules based on FD alone are critical.
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1562
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Auteur Catherine, A.; Selma, M.; Mouillot, D.; Troussellier, M.; Bernard, C.
Titre Patterns and multi-scale drivers of phytoplankton species richness in temperate peri-urban lakes Type Article scientifique
Année 2016 Publication Revue Abrégée Science of The Total Environment
Volume 559 Numéro Pages 74-83
Mots-Clés Lake- and catchment-scale; Phytoplankton; Productivity–diversity relationship; Random forest; Residuals analysis; species richness
Résumé Local species richness (SR) is a key characteristic affecting ecosystem functioning. Yet, the mechanisms regulating phytoplankton diversity in freshwater ecosystems are not fully understood, especially in peri-urban environments where anthropogenic pressures strongly impact the quality of aquatic ecosystems. To address this issue, we sampled the phytoplankton communities of 50 lakes in the Paris area (France) characterized by a large gradient of physico-chemical and catchment-scale characteristics. We used large phytoplankton datasets to describe phytoplankton diversity patterns and applied a machine-learning algorithm to test the degree to which species richness patterns are potentially controlled by environmental factors. Selected environmental factors were studied at two scales: the lake-scale (e.g. nutrients concentrations, water temperature, lake depth) and the catchment-scale (e.g. catchment, landscape and climate variables). Then, we used a variance partitioning approach to evaluate the interaction between lake-scale and catchment-scale variables in explaining local species richness. Finally, we analysed the residuals of predictive models to identify potential vectors of improvement of phytoplankton species richness predictive models. Lake-scale and catchment-scale drivers provided similar predictive accuracy of local species richness (R2 = 0.458 and 0.424, respectively). Both models suggested that seasonal temperature variations and nutrient supply strongly modulate local species richness. Integrating lake- and catchment-scale predictors in a single predictive model did not provide increased predictive accuracy; therefore suggesting that the catchment-scale model probably explains observed species richness variations through the impact of catchment-scale variables on in-lake water quality characteristics. Models based on catchment characteristics, which include simple and easy to obtain variables, provide a meaningful way of predicting phytoplankton species richness in temperate lakes. This approach may prove useful and cost-effective for the management and conservation of aquatic ecosystems.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1566
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Auteur Quétel, C.; Marinesque, S.; Ringler, D.; Fillinger, L.; Changeux, T.; Marteau, C.; Troussellier, M.
Titre Iles Eparses (SW Indian Ocean) as reference ecosystems for environmental research Type Article scientifique
Année 2016 Publication Revue Abrégée Acta Oecologica
Volume Numéro Pages 1-8
Mots-Clés Biodiversity sanctuaries; climate change; Environmental research; Iles Eparses; Indian Ocean; Pristine ecosystems
Résumé TAAF ensures since 2007 the management of 5 small tropical islands lying in the southwestern Indian Ocean: the Iles Eparses. These islands share an exceptional natural heritage including many marine and terrestrial endemic species. At a regional scale the Iles Eparses are some of the most pristine ecosystems, largely preserved from anthropogenic impacts due to their geographical isolation and a historically very limited human occupation. In this context, TAAF wished that Iles Eparses become unique natural laboratories for earth scientists and environmental process observation – like climate change impacts – but also sustainable biodiversity sanctuaries for which the scientific community should provide baseline ecological data to inform on appropriate conservation tools. An inter-agency research consortium emerged in 2009 to meet this commitment for the Iles Eparses. This program was intended to set a science framework in accordance with France' objectives for Research and Conservation. It enabled between 2009 and 2014 the implementation of 18 cross-disciplinary research projects ranging from geology to ecology and represented by the variety of the proposed articles in this special issue. Altogether research projects have dramatically increased knowledge on the Iles Eparses' ecosystems and have provided the first overview of their diversity, their functions and their dynamics and its determinants. In particular applied research efforts have supplied a significant amount of ecological evidence that is now available to develop optimal conservation strategy to ensure the Iles Eparses' long-term biodiversity value. These findings point out that the continuation of research activity in the Iles Eparses should be considered a priority.
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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
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1571
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