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Auteur Saulquin, B.; Fablet, R.; Mercier, G.; Demarcq, H.; Mangin, A.; d' Andon, O.H.F.
Titre Multiscale Event-Based Mining in Geophysical Time Series: Characterization and Distribution of Significant Time-Scales in the Sea Surface Temperature Anomalies Relatively to ENSO Periods from 1985 to 2009 Type Article scientifique
Année 2014 Publication Revue Abrégée IEEE J. Sel. Top. Appl. Earth Observ. Remote Sens.
Volume 7 Numéro (down) 8 Pages 3543-3552
Mots-Clés algorithm; climate-change; Distribution of the sea surface temperature anomalies events related to the ENSO periods; event-based mining in large geophysical datasets (big data); frequency; geophysical time series as series of significant time-scale events; models; monsoon variability; ocean; pacific; patterns; predictability; wavelet analysis
Résumé In this paper, one-dimensional (1-D) geophysical time series are regarded as series of significant time-scale events. We combine a wavelet-based analysis with a Gaussian mixture model to extract characteristic time-scales of 486 144 detected events in the Sea Surface Temperature Anomaly (SSTA) observed from satellite at global scale from 1985 to 2009. We retrieve four low-frequency characteristic time-scales of Nino Southern Oscillation (ENSO) in the 1.5- to 7-year range and show their spatial distribution. High-frequency (HF) SSTA event spatial distribution shows a dependency to the ENSO regimes, pointing out that the ENSO signal also involves specific signatures at these time-scales. These fine-scale signatures can hardly be retrieved from global EOF approaches, which tend to exhibit uppermost the low-frequency influence of ENSO onto the SSTA. In particular, we observe at global scale a major increase by 11% of the number of SSTA HF events during Nino periods, with a local maximum of 80% in Europe. The methodology is also used to highlight an ENSO-induced frequency shift during the major 1997-2000 ENSO event in the intertropical Pacific. We observe a clear shift from the high frequencies toward the 3.36-year scale with a maximum shift occurring 2 months before the ENSO maximum of energy at 3.36-year scale.
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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 1939-1404 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1205
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Auteur Mazel, F.; Guilhaumon, F.; Mouquet, N.; Devictor, V.; Gravel, D.; Renaud, J.; Cianciaruso, M.V.; Loyola, R.; Diniz, J.A.F.; Mouillot, D.; Thuiller, W.
Titre Multifaceted diversity-area relationships reveal global hotspots of mammalian species, trait and lineage diversity Type Article scientifique
Année 2014 Publication Revue Abrégée Global Ecology and Biogeography
Volume 23 Numéro (down) 8 Pages 836-847
Mots-Clés Conservation biogeography; Hill's numbers; biodiversity hotspots; congruent; conservation priorities; diversity indices; ecoregions; endemism; evolutionary; functional diversity-area; histories; mammals; phylogenetic diversity; phylogenetic diversity-area; relationship; richness gradients; spatial-patterns; species-area relationship
Résumé Aim To define biome-scale hotspots of phylogenetic and functional mammalian biodiversity (PD and FD, respectively) and compare them with 'classical' hotspots based on species richness (SR) alone. Location Global. Methods SR, PD and FD were computed for 782 terrestrial ecoregions using the distribution ranges of 4616 mammalian species. We used a set of comprehensive diversity indices unified by a recent framework incorporating the relative species coverage in each ecoregion. We built large-scale multifaceted diversity-area relationships to rank ecoregions according to their levels of biodiversity while accounting for the effect of area on each facet of diversity. Finally we defined hotspots as the top-ranked ecoregions. Results While ignoring relative species coverage led to a fairly good congruence between biome-scale top ranked SR, PD and FD hotspots, ecoregions harbouring a rich and abundantly represented evolutionary history and FD did not match with the top-ranked ecoregions defined by SR. More importantly PD and FD hotspots showed important spatial mismatches. We also found that FD and PD generally reached their maximum values faster than SR as a function of area. Main conclusions The fact that PD/FD reach their maximum value faster than SR could suggest that the two former facets might be less vulnerable to habitat loss than the latter. While this point is expected, it is the first time that it has been quantified at a global scale and should have important consequences for conservation. Incorporating relative species coverage into the delineation of multifaceted hotspots of diversity led to weak congruence between SR, PD and FD hotspots. This means that maximizing species number may fail to preserve those nodes (in the phylogenetic or functional tree) that are relatively abundant in the ecoregion. As a consequence it may be of prime importance to adopt a multifaceted biodiversity perspective to inform conservation strategies at a global scale.
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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 1466-822x ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 722
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Auteur VAN BEVEREN, E.; BONHOMMEAU, S.; FROMENTIN, J.-M.; BIGOT, J.-L.; BOURDEIX, J.-H.; BROSSET, P.; ROOS, D.; SARAUX, C.
Titre Rapid changes in growth, condition, size and age of small pelagic fish in the Mediterranean Type Article scientifique
Année 2014 Publication Marine Biology Revue Abrégée
Volume 161 Numéro (down) 8 Pages 1809-1822
Mots-Clés
Résumé Since 2007, the ecosystem of the Gulf of Lions has shifted to a different regime, characterised by a low anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) biomass and a remarkably high sprat (Sprattus sprattus) biomass. Surprisingly, the abundance and recruitment of anchovy and sardine remained high. To understand which processes (bottom-up or top-down control, etc.) could have caused this shift, we studied the changes in body condition, growth and size and age of anchovy, sardine and sprat over 1984–1985 and 1992–2012, using data from scientific surveys. The annual age structure of anchovy and sardine was estimated using Bayesian mixture models based on size frequency data with priors on the age–length relationship derived from independent otolith readings. The results indicated periods during which anchovy and sardine were in an average (1992–2004), good (2005–2007) or poor (2008–2012) overall state of condition. For sardine, the shift towards smaller fish observed during these past 4 years was explained by a combination of slower growth and the disappearance of older individuals (ages 2+). Despite the increase in biomass of sprat since 2008, indications were found that sprat was also smaller than in the past. As growth and condition decreased and overexploitation has not been documented or suspected for those three species in this area, we propose that the current decline in sardine and anchovy biomass could be due to qualitative and/or quantitative modifications in the planktonic production (i.e. a bottom-up control) or mass mortalities of adults due to an epidemic disease.
Adresse Univ Montpellier 2, Res Unit EME UMR 212, F-34203 Sete, France.
Auteur institutionnel Thèse
Editeur Springer Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0025-3162 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 30335 collection 986
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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 (down) 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 Avadi, A.; Freon, P.; Tam, J.
Titre Coupled ecosystem/supply chain modelling of fish products from sea to shelf : the Peruvian anchoveta case Type Article scientifique
Année 2014 Publication Revue Abrégée Plos One
Volume 9 Numéro (down) 7 Pages
Mots-Clés
Résumé Sustainability assessment of food supply chains is relevant for global sustainable development. A framework is proposed for analysing fishfood (fish products for direct human consumption) supply chains with local or international scopes. It combines a material flow model (including an ecosystem dimension) of the supply chains, calculation of sustainability indicators (environmental, socio-economic, nutritional), and finally multi-criteria comparison of alternative supply chains (e.g. fates of landed fish) and future exploitation scenarios. The Peruvian anchoveta fishery is the starting point for various local and global supply chains, especially via reduction of anchoveta into fishmeal and oil, used worldwide as a key input in livestock and fish feeds. The Peruvian anchoveta supply chains are described, and the proposed methodology is used to model them. Three scenarios were explored: status quo of fish exploitation (Scenario 1), increase in anchoveta landings for food (Scenario 2), and radical decrease in total anchoveta landings to allow other fish stocks to prosper (Scenario 3). It was found that Scenario 2 provided the best balance of sustainability improvements among the three scenarios, but further refinement of the assessment is recommended. In the long term, the best opportunities for improving the environmental and socio-economic performance of Peruvian fisheries are related to sustainability-improving management and policy changes affecting the reduction industry. Our approach provides the tools and quantitative results to identify these best improvement opportunities.
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1145
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