|   | 
Détails
   web
Enregistrements
Auteur Demarcq, H.; Reygondeau, G.; Alvain, S.; Vantrepotte, V.
Titre Monitoring marine phytoplankton seasonality from space Type Article scientifique
Année 2012 Publication Revue Abrégée Remote Sensing of Environment
Volume 117 Numéro Pages 211-222
Mots-Clés Biogeography; Phytoplankton; Phytoplankton Functional; remote sensing; seasonality; Seasonal parameters; Surface chlorophyll concentration; Types; Wavelet transform
Résumé Remote sensing techniques are used to study the large scale patterns related to the seasonal modes of variability of the marine phytoplankton. Ten years of monthly composite maps of sea surface chlorophyll-a concentration and the PHYSAT database of four Phytoplanktonic Functional Types (PFTs), both from SeaWiFS, are used to investigate characteristics of phytoplankton seasonality in the trades and westerlies wind oceanic biomes, where data density is adequate. We use a combination of wavelet transform and statistical techniques that allow us to quantify both intensity and duration of the seasonal oscillation of chlorophyll-a concentration and PFTs relative occurrence, and to map these relationships. Next, the seasonal oscillations detected are related to four PFTs revealing six major global phytoplanktonic associations. Our results elucidate the intensity and duration of the seasonal dynamic of the chlorophyll-a concentration and of the relative occurrence of four PFTs at a global scale. Thus, the typology of the different types of seasonality is investigated. Finally, an overall agreement between the results and the biogeochemical provinces partition proposed by Longhurst is found, revealing a strong environmental control on the seasonal oscillation of primary producers and a clear latitudinal organization in the succession of the phytoplankton types. Results provided in this study quantify the seasonal oscillation of key structural parameters of the global ocean, and their potential implications for our understanding of ecosystem dynamics.
Adresse
Auteur institutionnel Thèse
Editeur 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 0034-4257 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel LL @ pixluser @ collection 182
Lien permanent pour cet enregistrement
 

 
Auteur Dhurmeea, Z.; Pethybridge, H.; Langlais, C.; Somes, C.J.; Nikolic, N.; Bourjea, J.; Appadoo, C.; Bodin, N.
Titre Spatial variation in stable isotopes and fatty acid trophic markers in albacore tuna (Thunnus alalunga) from the western Indian Ocean Type Article scientifique
Année 2020 Publication Revue Abrégée Deep Sea Research Part I: Oceanographic Research Papers
Volume Numéro Pages 103286
Mots-Clés Climate change; Environmental parameters; Phytoplankton; Trophodynamics
Résumé Albacore tuna (Thunnus alalunga) is a highly economically important species in the western Indian Ocean. However, knowledge of its ecological and nutritional characteristics, essential for proper management of the species, is lacking in the region. The trophodynamics of the Indian Ocean albacore was thus examined using known fatty acid trophic markers (FATMs) of primary producers, nutritional condition indices (NCIs) (omega-3/omega-6 ratio and total fatty acid content (TFA)), and baseline and lipid corrected stable isotope of carbon (δ13Ccorr) and nitrogen (δ15Ncorr), measured in the muscle tissue. We applied generalized additive mixed models to understand the spatiotemporal patterns and drivers of these tracers, taking into consideration several intrinsic and extrinsic variables: fish size, fishing position, month, chlorophyll-a and sea surface temperature (SST). Both chlorophyll-a and SST were significant as single explanatory variables for all tracers with SST being the best predictor for docosahexaenoic acid/eicosapentaenoic acid ratio, the omega-6 protists FATM, omega-3/omega-6 ratio, δ13Ccorr and δ15Ncorr. TFA was best predicted by fish size only. Higher primary productivity, as inferred by high δ13Ccorr values and diatom contribution, nutritional condition and trophic position, as inferred by high δ15Ncorr values, were observed in albacore from the temperate southern waters than in the northern tropical regions. Relationships between environmental variables and corrected stable isotopes, FATMs confirm that ocean warming and changes in primary productivity will impact nutrient flow and energy transfer in the marine food web which may have negative nutritional outcomes for albacore. This knowledge is particularly crucial in areas where oceanographic conditions and seawater temperatures are changing at a fast rate and should also be taken into consideration by fisheries managers.
Adresse
Auteur institutionnel Thèse
Editeur Lieu de Publication Éditeur
Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0967-0637 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2783
Lien permanent pour cet enregistrement
 

 
Auteur Follesa, M.C.; Marongiu, M.F.; Zupa, W.; Bellodi, A.; Cau, A.; Cannas, R.; Colloca, F.; Djurovic, M.; Isajlovic, I.; Jadaud, A.; Manfredi, C.; Mulas, A.; Peristeraki, P.; Porcu, C.; Ramirez-Amaro, S.; Salmeron Jimenez, F.; Serena, F.; Sion, L.; Thasitis, I.; Cau, A.; Carbonara, P.
Titre Spatial variability of Chondrichthyes in the northern Mediterranean Type Article scientifique
Année 2019 Publication Revue Abrégée Sci. Mar.
Volume 83 Numéro Pages 81-100
Mots-Clés abundance; adriatic sea; balearic-islands; bottom trawl surveys; by-catch; Chondrichthyes; demersal assemblages; depth distribution; distribution; dynamics; elasmobranchs; fish; fisheries; Mediterranean; parameters; patterns
Résumé Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families). 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth). while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicida and the Torpediniformes Torpedo matmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavaia and then by R. miraleius, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canictda, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers.
Adresse
Auteur institutionnel Thèse
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 0214-8358 ISBN Médium
Région Expédition Conférence
Notes WOS:000504829900007 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2700
Lien permanent pour cet enregistrement
 

 
Auteur Garrido, M.; Cecchi, P.; Vaquer, A.; Pasqualini, V.
Titre Effects of sample conservation on assessments of the photosynthetic efficiency of phytoplankton using PAM fluorometry Type Article scientifique
Année 2013 Publication Revue Abrégée Deep-Sea Res. Part I-Oceanogr. Res. Pap.
Volume 71 Numéro Pages 38-48
Mots-Clés diatom, quantum yield, temperature, parameters; PAM fluorescence, Phytoplankton, Temperature Biguglia lagoon; physiological-responses, marine-phytoplankton, oxygen evolution, benthic; rapid light curves, chlorophyll-a fluorescence, in-vivo,
Résumé Pulse Amplitude Modulated (PAM) fluorometry is now a widely used method for the assessment of phytoplankton fitness, with an increasing popularity in field assessments. It is usually recommended to carry out measurements swiftly after collection, but the number of samples and analytical procedures needed to obtain valuable datasets sometimes makes immediate analysis impracticable, forcing delays between fluorescence measurements. Conservation conditions of samples before analysis may potentially affect their photosynthetic performances but no formal study documenting such impacts appears available in the literature. The aim of this study was to investigate the effects of storage conditions (temperature, duration) on photosynthetic parameters in different phytoplankton communities (characterized in situ by a BBE fluoroprobe) sampled during summer in different environmental locations in a Mediterranean lagoon (Biguglia lagoon, Corsica, France). PAM-fluorescence parameters were measured after three different conservation durations (2-4 h, 6-8 h and 10-12 h after collection) on samples stored at three different temperatures (15 degrees C, 25 degrees C and 35 degrees C). Results showed that storage at the highest temperature severely impacted photosynthetic parameters, with cumulative effects as storage duration increased. For phytoplankton samples collected in warm or tropical environments, storage at “room temperature” (25 degrees C) only appeared a valid option if measurements have to be carried out strictly within a very short delay. Inversely, cooling the samples (i.e. conservation at 15 degrees C) did not induce significant effects, independently of storage duration. Cooling appeared the best solution when sampling-to-analysis delay goes over a few hours. Long-term storage ( > 8 h) should definitively be avoided. (C) 2012 Elsevier Ltd. All rights reserved.
Adresse
Auteur institutionnel Thèse
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 0967-0637 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 552
Lien permanent pour cet enregistrement
 

 
Auteur Griot, R.; Allal, F.; Brard-Fudulea, S.; Morvezen, R.; Haffray, P.; Phocas, F.; Vandeputte, M.
Titre APIS: An auto-adaptive parentage inference software that tolerates missing parents Type Article scientifique
Année 2020 Publication Revue Abrégée Mol. Ecol. Resour.
Volume 20 Numéro 2 Pages 579-590
Mots-Clés errors; fitness; genetic-parameters; guide; identification; impact; markers; microsatellites; missing parents; natural-populations; parentage assignment; pedigree; snp
Résumé In the context of parentage assignment using genomic markers, key issues are genotyping errors and an absence of parent genotypes because of sampling, traceability or genotyping problems. Most likelihood-based parentage assignment software programs require a priori estimates of genotyping errors and the proportion of missing parents to set up meaningful assignment decision rules. We present here the R package APIS, which can assign offspring to their parents without any prior information other than the offspring and parental genotypes, and a user-defined, acceptable error rate among assigned offspring. Assignment decision rules use the distributions of average Mendelian transmission probabilities, which enable estimates of the proportion of offspring with missing parental genotypes. APIS has been compared to other software (CERVUS, VITASSIGN), on a real European seabass (Dicentrarchus labrax) single nucleotide polymorphism data set. The type I error rate (false positives) was lower with APIS than with other software, especially when parental genotypes were missing, but the true positive rate was also lower, except when the theoretical exclusion power reached 0.99999. In general, APIS provided assignments that satisfied the user-set acceptable error rate of 1% or 5%, even when tested on simulated data with high genotyping error rates (1% or 3%) and up to 50% missing sires. Because it uses the observed distribution of Mendelian transmission probabilities, APIS is best suited to assigning parentage when numerous offspring (>200) are genotyped. We have demonstrated that APIS is an easy-to-use and reliable software for parentage assignment, even when up to 50% of sires are missing.
Adresse
Auteur institutionnel Thèse
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 1755-098x ISBN Médium
Région Expédition Conférence
Notes WOS:000496576600001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2760
Lien permanent pour cet enregistrement