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Auteur Zilius, M.; Bartoli, M.; Bresciani, M.; Katarzyte, M.; Ruginis, T.; Petkuviene, J.; Lubiene, I.; Giardino, C.; Bukaveckas, P.A.; De Wit, R.; Razinkovas-Baziukas, A.
Titre Feedback Mechanisms Between Cyanobacterial Blooms, Transient Hypoxia, and Benthic Phosphorus Regeneration in Shallow Coastal Environments Type Article scientifique
Année 2014 Publication Revue Abrégée Estuaries and Coasts
Volume 37 Numéro 3 Pages (down) 680-694
Mots-Clés baltic sea; chesapeake bay; curonian lagoon; Cyanobacterial blooms; ecosystem metabolism; Estuary; gulf; Hypoxia; Net; nutrient limitation; Oxygen; Phosphorus release; respiration; satellite data; temporal variability
Résumé We investigated the dissolved oxygen metabolism of the Curonian Lagoon (Baltic Sea) to assess the relative contributions of pelagic and benthic processes to the development of transient hypoxic conditions in shallow water habitats. Metabolism measurements along with the remote sensing-derived estimates of spatial variability in chlorophyll a were used to evaluate the risk of hypoxia at the whole lagoon level. Our data demonstrate that cyanobacterial blooms strongly inhibit light penetration, resulting in net heterotrophic conditions in which pelagic oxygen demand exceeds benthic oxygen demand by an order of magnitude. The combination of bloom conditions and reduced vertical mixing during calm periods resulted in oxygen depletion of bottom waters and greater sediment nutrient release. The peak of reactive P regeneration (nearly 30 mu mol m(-2) h(-1)) coincided with oxygen depletion in the water column, and resulted in a marked drop of the inorganic N:P ratio (from > 40 to < 5, as molar). Our results suggest a strong link between cyanobacterial blooms, pelagic respiration, hypoxia, and P regeneration, which acts as a feedback in sustaining algal blooms through internal nutrient cycling. Meteorological data and satellite-derived maps of chlorophyll a were used to show that nearly 70 % of the lagoon surface (approximately 1,000 km(2)) is prone to transient hypoxia development when blooms coincide with low wind speed conditions.
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ISSN 1559-2723 ISBN Médium
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Notes <p>ISI Document Delivery No.: AF0SM<br/>Times Cited: 1<br/>Cited Reference Count: 66<br/>Zilius, Mindaugas Bartoli, Marco Bresciani, Mariano Katarzyte, Marija Ruginis, Tomas Petkuviene, Jolita Lubiene, Irma Giardino, Claudia Bukaveckas, Paul A. de Wit, Rutger Razinkovas-Baziukas, Arturas<br/>European Union Structural Funds project “Postdoctoral Fellowship Implementation in Lithuania”; Fulbright Fellowship; ESA project [AO-553]; CYAN-IS-WAS (Ministero dell'Istruzione dell'Universita e della Ricerca, Science and technological of Sweden); CLAM-PHYM (Italian Space Agency) [ASI I/015/11/0]<br/>Mindaugas Zilius was supported by a postdoctoral fellowship funded by the European Union Structural Funds project “Postdoctoral Fellowship Implementation in Lithuania.” Paul Bukaveckas was supported by a Fulbright Fellowship during his residence at Klaipeda University. MERIS data were made available through the ESA project AO-553 (MELINOS). This study was co-funded by CYAN-IS-WAS (Ministero dell'Istruzione dell'Universita e della Ricerca, Science and technological cooperation between Italy and the Kingdom of Sweden) and CLAM-PHYM (Italian Space Agency, contract ASI I/015/11/0) projects. We gratefully thank the Lithuanian Hydrometeorological Service of the Ministry of Environment for providing meteorological data. We also gratefully thank three anonymous reviewers for valuable comments which improved the quality of the manuscript.<br/>Springer<br/>New york</p> Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1184
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Auteur Nguyen-Kim, H.; Bouvier, T.; Bouvier, C.; Hai, D.N.; Lam, N.N.; Rochelle-Newall, E.; Baudoux, A.C.; Desnues, C.; Reynaud, S.; Ferrier-Pages, C.; Bettarel, Y.
Titre High occurrence of viruses in the mucus layer of scleractinian corals Type Article scientifique
Année 2014 Publication Revue Abrégée Environmental Microbiology Reports
Volume 6 Numéro 6 Pages (down) 675-682
Mots-Clés abundance; bacteria; communities; diversity; ecology; gradient gel-electrophoresis; level physiological profiles; microbial; reef; release; water
Résumé Viruses attract increasing interest from environmental microbiologists seeking to understand their function and role in coral health. However, little is known about their main ecological traits within the coral holobiont. In this study, a quantitative and qualitative characterization of viral and bacterial communities was conducted on the mucus of seven different coral species of the Van Phong Bay (Vietnam). On average, the concentrations of viruses and bacteria were, respectively, 17- and twofold higher in the mucus than in the surrounding water. The examination of bacterial community composition also showed remarkable differences between mucus and water samples. The percentage of active respiring cells was nearly threefold higher in mucus (m=24.8%) than in water (m=8.6%). Interestingly, a positive and highly significant correlation was observed between the proportion of active cells and viral abundance in the mucus, suggesting that the metabolism of the bacterial associates is probably a strong determinant of the distribution of viruses within the coral holobiont. Overall, coral mucus, given its unique physicochemical characteristics and sticking properties, can be regarded as a highly selective biotope for abundant, diversified and specialized symbiotic microbial and viral organisms.
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ISSN 1758-2229 ISBN Médium
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Notes <p>ISI Document Delivery No.: AU6GU<br/>Times Cited: 1<br/>Cited Reference Count: 51<br/>Nguyen-Kim, Hanh Bouvier, Thierry Bouvier, Corinne Hai Doan-Nhu Lam Nguyen-Ngoc Rochelle-Newall, Emma Baudoux, Anne-Claire Desnues, Christelle Reynaud, Stephanie Ferrier-Pages, Christine Bettarel, Yvan<br/>EC2CO CORINE Project; TOTAL Foundation; French Institute of Research for Development (IRD)<br/>This work was supported by the EC2CO CORINE Project, the TOTAL Foundation and the French Institute of Research for Development (IRD). We thank Telesphore Sime-Ngando, Didier Debroas, Pham The Thu, Chu Van Thuoc, Sonia Monteil and Delphine Bonnet for their participation in the CORINE mission in Vietnam, their assistance in diving, field operations and technical support during the cruise, and Sebastien Villeger for his advice on statistical analysis. We are also very grateful to Michel Galey, Alexandre Portier and all the staff from Whale Island Resort for their hospitality and help during our stay.<br/>Wiley-blackwell<br/>Hoboken</p> Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1170
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Auteur Zupan, L.; Cabeza, M.; Maiorano, L.; Roquet, C.; Devictor, V.; Lavergne, S.; Mouillot, D.; Mouquet, N.; Renaud, J.; Thuiller, W.
Titre Spatial mismatch of phylogenetic diversity across three vertebrate groups and protected areas in Europe Type Article scientifique
Année 2014 Publication Revue Abrégée Diversity and Distributions
Volume 20 Numéro 6 Pages (down) 674-685
Mots-Clés Europe; Species diversity; approach; biodiversity; climate-change; communities; ecological; evolutionary diversity; functional diversity; global patterns; hotspots; nature conservation; phylogenetic diversity; protected areas; spatial biodiversity congruence; species richness; terrestrial vertebrates; unified
Résumé Aim We investigate patterns of phylogenetic diversity in relation to species diversity for European birds, mammals and amphibians to evaluate their congruence and highlight areas of particular evolutionary history. We estimate the extent to which the European network of protected areas (PAs) network retains interesting evolutionary history areas for the three groups separately and simultaneously. Location Europe Methods Phylogenetic (QE(PD)) and species diversity (SD) were estimated using the Rao's quadratic entropy at 10 ' resolution. We determined the regional relationship between QE(PD) and SD for each taxa with a spatial regression model and used the tails of the residuals (QE(RES)) distribution to identify areas of higher and lower QE(PD) than predicted. Spatial congruence of biodiversity between groups was assessed with Pearson correlation coefficient. A simple classification scheme allowed building a convergence map where a convergent pixel equalled to a QE(RES) value of the same sign for the three groups. This convergence map was overlaid to the current PAs network to estimate the level of protection in convergent pixels and compared it to a null expectation built on 1000 randomization of PAs over the landscape. Results QE(RES) patterns across vertebrates show a strong spatial mismatch highlighting different evolutionary histories. Convergent areas represent only 2.7% of the Western Palearctic, with only 8.4% of these areas being covered by the current PAs network while a random distribution would retain 10.4% of them. QE(RES) are unequally represented within PAs: areas with higher QE(PD) than predicted are better covered than expected, while low QE(PD) areas are undersampled. Main conclusions Patterns of diversity strongly diverge between groups of vertebrates in Europe. Although Europe has the world's most extensive PAs network, evolutionary history of terrestrial vertebrates is unequally protected. The challenge is now to reconcile effective conservation planning with a contemporary view of biodiversity integrating multiple facets.
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ISSN 1366-9516 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 856
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Auteur 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 (down) 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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ISSN 0886-6236 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 554
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Auteur Lefevre, S.; Domenici, P.; McKenzie, D.J.
Titre Swimming in air-breathing fishes Type Article scientifique
Année 2014 Publication Revue Abrégée Journal of Fish Biology
Volume 84 Numéro 3 Pages (down) 661-681
Mots-Clés acid-base; aerobic metabolism; amia-calva; bimodal respiration; dicentrarchus-labrax; european sea-bass; exercise; exhaustive exercise; gar lepisosteus-platyrhincus; megalops-cyprinoides; pacific; partitioning; rainbow-trout; recovery; respiratory; tarpon; trout oncorhynchus-mykiss
Résumé Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise.
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ISSN 0022-1112 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 877
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