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Auteur (up) Bourgeois, S.; Hochard, S.; Pringault, O.
Titre Subtidal microphytobenthos: effects of inorganic and organic compound supplies on migration, production, and respiration in a tropical coastal environment Type Article scientifique
Année 2010 Publication Revue Abrégée Aquat. Microb. Ecol.
Volume 61 Numéro 1 Pages 13-29
Mots-Clés Amino acids; Autotroph-heterotroph coupling; Glucose; Nutrients; Oxygen; Reflectance; availability; benthic diatoms; chlorophyll-a fluorescence; coral-reef lagoon; headwater streams; hypersaline microbial mat; lagoon; marine; microelectrode; new-caledonia; nutrient; oxygenic photosynthesis; phytoplankton
Résumé Microphytobenthos (MPB) is an important primary producer in coastal ecosystems. In oligotrophic environments, its activity may be controlled by the availability of organic or inorganic compounds but also by its migration behavior. The objective of this study was to determine, in MPB-colonized subtidal sediments, the consequences of short-term enrichments (< 24 h) of organic (alanine, glutamate, and glucose) and inorganic (ammonium, phosphate) compounds on MPB vertical migration and metabolisms, net production (NP), areal gross production (AGP), and community respiration (R). Two contrasting stations located in the southwest lagoon of New Caledonia were investigated: 1 under strong anthropogenic influence and 1 under more oceanic influence. Both stations were dominated by epipelic diatoms. Differences in net primary production were explained by diurnal variation of MPB biomass at the sediment surface, showing the importance of MPB migration in the functioning of these subtidal environments. However, a stimulation or inhibition of MPB migration did not necessarily impact the net primary production of the system; this strongly depends upon the interactions between the autotrophic and heterotrophic compartments, the latter being controlled by the environmental conditions. For the station under low anthropogenic influence, AGP and R were both significantly stimulated by alanine, glucose, and ammonium, and significantly inhibited by phosphate. The similar responses of AGP and R to enrichments suggest that autotrophs and heterotrophs were tightly coupled. Conversely, in the station under strong anthropogenic influence, AGP and R responded differently. Addition of ammonium inhibited AGP without having an impact on R, whereas addition of phosphate inhibited R whilst having no measurable effect on AGP. In this station, the coupling between autotrophs and heterotrophs was weakened, suggesting that the carbon demand of the heterotrophic compartment is probably sustained by the supplies of allochthonous organic matter rather than by exudates from the autotrophic compartment.
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Volume de collection Numéro de collection Edition
ISSN 0948-3055 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 886
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Auteur (up) D'agata, S.; Mouillot, D.; Wantiez, L.; Friedlander, A.M.; Kulbicki, M.; Vigliola, L.
Titre Marine reserves lag behind wilderness in the conservation of key functional roles Type Article scientifique
Année 2016 Publication Revue Abrégée Nat. Commun.
Volume 7 Numéro Pages 12000
Mots-Clés biodiversity; coral-reef fishes; diversity indexes; ecosystem; new-caledonia; population-density; protected areas; species richness; visual-census; vulnerability
Résumé Although marine reserves represent one of the most effective management responses to human impacts, their capacity to sustain the same diversity of species, functional roles and biomass of reef fishes as wilderness areas remains questionable, in particular in regions with deep and long-lasting human footprints. Here we show that fish functional diversity and biomass of top predators are significantly higher on coral reefs located at more than 20 h travel time from the main market compared with even the oldest (38 years old), largest (17,500 ha) and most restrictive (no entry) marine reserve in New Caledonia (South-Western Pacific). We further demonstrate that wilderness areas support unique ecological values with no equivalency as one gets closer to humans, even in large and well-managed marine reserves. Wilderness areas may therefore serve as benchmarks for management effectiveness and act as the last refuges for the most vulnerable functional roles.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 2041-1723 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1625
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Auteur (up) Durand, J.-D.; Hubert, N.; Shen, K.-N.; Borsa, P.
Titre DNA barcoding grey mullets Type Article scientifique
Année 2017 Publication Revue Abrégée Rev. Fish. Biol. Fish.
Volume 27 Numéro 1 Pages 233-243
Mots-Clés coi; fish assemblages; genetics; identification; level; management; marine fishes; maximum-parsimony methods; mitochondrial phylogeny; Mugilidae; new-caledonia; south-america; species diversity; Taxonomy; teleostei mugilidae
Résumé Despite the ecological and commercial importance of grey mullets (fish family Mugilidae), their taxonomy and systematics are still much debated. Reasons for this are the low level of morphometric variability and the relatively poor phylogenetic information borne by the morpho-anatomical characters used thus far in diagnosing species. Here, we evaluate the potential of DNA barcoding to accurately delineate species and assign unknown specimens to taxa in the family Mugilidae. Our reference sample consists of 257 individuals from 91 lineages characterized by their nucleotide sequences at the COI, cytochrome b, and 16S rRNA loci. These lineages correspond to 55 species according to the current taxonomy, and 36 presumed cryptic species. All known and presumed cryptic species within the 'Mugil cephalus' (n = 15) and 'M. curema' (n = 6) species complexes, as well as within genera Chelon (n = 10), Crenimugil (n = 6), Osteomugil (n = 6), and Planiliza (n = 18) were successfully recovered as distinct lineages by COI gene sequences (598 bp), demonstrating the utility of this marker to delineate species in the family Mugilidae. Inconsistencies in the labeling of sequences deposited in GenBank were ascribed to species misidentification. A proportion of these misidentifications occurred in the course of dedicated barcoding surveys, further emphasizing the need for an accurate and exhaustive reference barcoding database for Mugilidae.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0960-3166 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2109
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Auteur (up) Mari, X.; Lefevre, J.; Torreton, J.P.; Bettarel, Y.; Pringault, O.; Rochelle-Newall, E.; Marchesiello, P.; Menkes, C.; Rodier, M.; Migon, C.; Motegi, C.; Weinbauer, M.G.; Legendre, L.
Titre Effects of soot deposition on particle dynamics and microbial processes in marine surface waters Type Article scientifique
Année 2014 Publication Revue Abrégée Global Biogeochemical Cycles
Volume 28 Numéro 7 Pages 662-678
Mots-Clés aerosols; black carbon; coral-reef lagoon; dissolved organic-matter; new-caledonia; ocean; Sea; sediments; size spectra; tep
Résumé Large amounts of soot are continuously deposited on the global ocean. Even though significant concentrations of soot particles are found in marine waters, the effects of these aerosols on ocean ecosystems are currently unknown. Using a combination of in situ and experimental data, and results from an atmospheric transport model, we show that the deposition of soot particles from an oil-fired power plant impacted biogeochemical properties and the functioning of the pelagic ecosystem in tropical oligotrophic oceanic waters off New Caledonia. Deposition was followed by a major increase in the volume concentration of suspended particles, a change in the particle size spectra that resulted from a stimulation of aggregation processes, a 5% decrease in the concentration of dissolved organic carbon (DOC), a decreases of 33 and 23% in viral and free bacterial abundances, respectively, and a factor similar to 2 increase in the activity of particle-attached bacteria suggesting that soot introduced in the system favored bacterial growth. These patterns were confirmed by experiments with natural seawater conducted with both soot aerosols collected in the study area and standard diesel soot. The data suggest a strong impact of soot deposition on ocean surface particles, DOC, and microbial processes, at least near emission hot spots.
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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 0886-6236 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 554
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Auteur (up) Pringault, O.; Viret, H.; Duran, R.
Titre Interactions between Zn and bacteria in marine tropical coastal sediments Type Article scientifique
Année 2012 Publication Revue Abrégée Environ. Sci. Pollut. Res.
Volume 19 Numéro 3 Pages 879-892
Mots-Clés Bacterial diversity; Metal spiking; Microcosms; New Caledonia; T-Rflp; baltic sea sediments; community; coral-reef lagoon; fragment-length-polymorphism; heavy-metals; hypersaline microbial mat; new-caledonia lagoon; polluted anoxic sediments; salins-de-giraud; south-west lagoon; tolerance pict
Résumé Purpose The main goals of this study were (1) to examine the effects of zinc on the microbial community structure of anthropogenically impacted sediments in a tropical coastal ecosystem and (2) to determine whether these microbial benthic communities may enhance the adsorption of zinc. Methods The interactions between zinc and bacteria in tropical sediments were studied in sediment microcosms amended with 2.5 mg L-1 of Zn in the water phase and incubated for 8 days under different environmental conditions, oxic/anoxic and glucose addition. At the end of incubation, microbial structure was assessed by molecular fingerprints (T-RFLP) analysis and Zn speciation in the sediment was determined by sequential extraction. Results In the three studied sediments, Zn spiking resulted in only slight changes in bacterial community structure. In contrast, the addition of low concentrations of glucose (5mM) strongly modified the bacterial community structure: <20% of similarity with the initial structure concomitant with a strong diminution of the specific richness. Overall, these results suggest that highly labile organic matter has a larger impact on microbial structure than heavy metal. These weak impacts of Zn on bacteria diversity might be partly explained by (1) the strong adsorption of Zn in the presence of bacteria and/or (2) the incorporation of Zn into a nonbioavailable fraction. Nevertheless, Zn spiking resulted in significant changes in nutrient cycles, suggesting that bacterial metabolisms were impacted by the heavy metal. This led to an increase in nutrient supplies to the water column, potentially enhancing eutrophication in a nutrient-limited, oligotrophic ecosystem.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0944-1344 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 683
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