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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 (up) 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
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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 Moreau, S.; Mostajir, B.; Almandoz, G.O.; Demers, S.; Hernando, M.; Lemarchand, K.; Lionard, M.; Mercier, B.; Roy, S.; Schloss, I.R.; Thyssen, M.; Ferreyra, G.A.
Titre Effects of enhanced temperature and ultraviolet B radiation on a natural plankton community of the Beagle Channel (southern Argentina): a mesocosm study Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Aquatic Microbial Ecology
Volume 72 Numéro 2 Pages 155-173
Mots-Clés
Résumé ABSTRACT: Marine planktonic communities can be affected by increased temperatures associated with global climate change, as well as by increased ultraviolet B radiation (UVBR, 280-320 nm) through stratospheric ozone layer thinning. We studied individual and combined effects of increased temperature and UVBR on the plankton community of the Beagle Channel, southern Patagonia, Argentina. Eight 2 m3 mesocosms were exposed to 4 treatments (with 2 replicates) during 10 d: (1) control (natural temperature and UVBR), (2) increased UVBR (simulating a 60% decrease in stratospheric ozone layer thickness), (3) increased temperature (+ 3°C), and (4) simultaneous increased temperature and UVBR (60% decrease in stratospheric ozone; + 3°C). Two distinct situations were observed with regard to phytoplankton biomass: bloom (Days 1-4) and post-bloom (Days 5-9). Significant decreases in micro-sized diatoms (>20 µm), bacteria, chlorophyll a, and particulate organic carbon concentrations were observed during the post-bloom in the enhanced temperature treatments relative to natural temperature, accompanied by significant increases in nanophytoplankton (10-20 µm, mainly prymnesiophytes). The decrease in micro-sized diatoms in the high temperature treatment may have been caused by a physiological effect of warming, although we do not have activity measurements to support this hypothesis. Prymnesiophytes benefited from micro-sized diatom reduction in their competition for resources. The bacterial decrease under warming may have been due to a change in the dissolved organic matter release caused by the observed change in phytoplankton composition. Overall, the rise in temperature affected the structure and total biomass of the communities, while no major effect of UVBR was observed on the plankton community.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 555
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Auteur Delzor, A.; Couratier, P.; Boumédiène, F.; Nicol, M.; Druet-Cabanac, M.; Paraf, F.; Méjean, A.; Ploux, O.; Leleu, J.-P.; Brient, L.; Lengronne, M.; Pichon, V.; Combès, A.; El Abdellaoui, S.; Bonneterre, V.; Lagrange, E.; Besson, G.; Bicout, D.J.; Boutonnat, J.; Camu, W.; Pageot, N.; Juntas-Morales, R.; Rigau, V.; Masseret, E.; Abadie, E.; Preux, P.-M.; Marin, B.
Titre Searching for a link between the L-BMAA neurotoxin and amyotrophic lateral sclerosis: a study protocol of the French BMAALS programme Type (up) Article scientifique
Année 2014 Publication Revue Abrégée BMJ Open
Volume 4 Numéro 8 Pages
Mots-Clés
Résumé Introduction Amyotrophic lateral sclerosis (ALS) is the most common motor neurone disease. It occurs in two forms: (1) familial cases, for which several genes have been identified and (2) sporadic cases, for which various hypotheses have been formulated. Notably, the β-N-methylamino-L-alanine (L-BMAA) toxin has been postulated to be involved in the occurrence of sporadic ALS. The objective of the French BMAALS programme is to study the putative link between L-BMAA and ALS.Methods and analysis The programme covers the period from 1 January 2003 to 31 December 2011. Using multiple sources of ascertainment, all the incident ALS cases diagnosed during this period in the area under study (10 counties spread over three French regions) were collected. First, the standardised incidence ratio will be calculated for each municipality under concern. Then, by applying spatial clustering techniques, overincidence and underincidence zones of ALS will be sought. A case–control study, in the subpopulation living in the identified areas, will gather information about patients’ occupations, leisure activities and lifestyle habits in order to assess potential risk factors to which they are or have been exposed. Specimens of drinking water, food and biological material (brain tissue) will be examined to assess the presence of L-BMAA in the environment and tissues of ALS cases and controls.Ethics and dissemination The study has been reviewed and approved by the French ethical committee of the CPP SOOM IV (Comité de Protection des Personnes Sud-Ouest & Outre-Mer IV). The results will be published in peer-reviewed journals and presented at national and international conferences.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 818
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Auteur Katsanevakis, S.; Coll, M.; Piroddi, C.; Steenbeek, J.; Ben Rais Lasram, F.; Zenetos, A.; Cardoso, A.C.
Titre Invading the Mediterranean Sea: biodiversity patterns shaped by human activities Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Front. Mar. Sci
Volume 1 Numéro Pages
Mots-Clés alien species; Aquaculture; biodiversity patterns; biological invasions; Lessepsian migrants; pathways; shipping
Résumé Human activities, such as shipping, aquaculture, and the opening of the Suez Canal, have led to the introduction of nearly 1000 alien species into the Mediterranean Sea. We investigated how human activities, by providing pathways for the introduction of alien species, may shape the biodiversity patterns in the Mediterranean Sea. Richness of Red Sea species introduced through the Suez Canal (Lessepsian species) is very high along the eastern Mediterranean coastline, reaching a maximum of 129 species per 100 km2, and declines toward the north and west. The distribution of species introduced by shipping is strikingly different, with several hotspot areas occurring throughout the Mediterranean basin. Two main hotspots for aquaculture-introduced species are observed (the Thau and Venice lagoons). Certain taxonomic groups were mostly introduced through specific pathways—fish through the Suez Canal, macrophytes by aquaculture, and invertebrates through the Suez Canal and by shipping. Hence, the local taxonomic identity of the alien species was greatly dependent on the dominant maritime activities/interventions and the related pathways of introduction. The composition of alien species differs among Mediterranean ecoregions; such differences are greater for Lessepsian and aquaculture-introduced species. The spatial pattern of native species biodiversity differs from that of alien species: the overall richness of native species declines from the north-western to the south-eastern regions, while the opposite trend is observed for alien species. The biodiversity of the Mediterranean Sea is changing, and further research is needed to better understand how the new biodiversity patterns shaped by human activities will affect the Mediterranean food webs, ecosystem functioning, and the provision of ecosystem services.
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Numéro d'Appel collection 313
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Auteur Sequeira, A.M.M.; Mellin, C.; Floch, L.; Williams, P.G.; Bradshaw, C.J.A.
Titre Inter-ocean asynchrony in whale shark occurrence patterns Type (up) Article scientifique
Année 2014 Publication Revue Abrégée Journal of Experimental Marine Biology and Ecology
Volume 450 Numéro Pages 21-29
Mots-Clés <!–; –><keyword; Handled; id=; Not; Tag
Résumé Abstract The whale shark (Rhincodon typus, Smith, 1828) is a migratory species (classed as Vulnerable by the IUCN) with genetic and circumstantial evidence for inter-ocean connectivity. Given this migratory behaviour, population-wide occurrence trends can only be contextualized by examining the synchrony in occurrence patterns among locations where they occur. We present a two-step modelling approach of whale shark spatial and temporal probability of occurrence in the Atlantic and Pacific Oceans using generalized linear mixed-effects models. To test the hypothesis that the probability of whale shark occurrence is asynchronous across oceans, as expected if inter-ocean migration occurs, we used long-term datasets of whale shark sightings derived from tuna purse-seine logbooks covering most of the central-east Atlantic (1980–2010) and western Pacific (2000–2010). We predicted seasonal habitat suitability to produce maps in each area, and then evaluated the relative effect of time (year) on the probability of occurrence to test whether it changed over the study period. We also applied fast Fourier transforms to determine if any periodicity was apparent in whale shark occurrences in each ocean. After partialling out the effects of seasonal patterns in spatial distribution and sampling effort, we found no evidence for a temporal trend in whale shark occurrence in the Atlantic, but there was a weak trend of increasing probability of occurrence in the Pacific. The highest-ranked model for the latter included a spatial predictor of occurrence along with fishing effort, a linear term for time, and a random temporal effect (year), explaining 15% of deviance in whale shark probability of occurrence. Fast Fourier transforms revealed a prominent 15.5-year cycle in the Atlantic. The increase in the probability of occurrence in the Pacific is concurrent with a decrease previously detected in the Indian Ocean. Cyclic patterns driven by migratory behaviour would better explain temporal trends in whale shark occurrence at the oceanic scale. However, despite cycles partially explaining observations of fewer sharks in some years, overall reported sighting rate has been decreasing. As a result, we suggest that the current {IUCN} status of the species should be re-assessed, but more data are needed to examine the flow of individuals across oceans and to identify possible reasons for asynchronous occurrences.
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ISSN 0022-0981 ISBN Médium
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Numéro d'Appel LL @ pixluser @ collection 314
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