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See detailThe review of Audiovisual Media Services Directive: many political voices for one digital Europe?
Vlassis, Antonios ULiege

in Politique Européenne (2017), 56

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See detailLa politique européenne de la culture. Entre paradigme économique et rhétorique de l'exception
Calligaro, Oriane; Vlassis, Antonios ULiege

in Politique Européenne (2017), 56

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See detailOutreach activities: harmonisation or standardisation of security postures?
Paile, Sylvain ULiege

in Michel, Quentin; Lehofer, Wolfgang (Eds.) Incentives of Europe for Non-Proliferation Outreach Activities (2017)

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See detailEmergent vortex phenomena in spatially and temporally modulated superconducting condensates
Jelic, Zeljko ULiege

Doctoral thesis (2017)

Superconductivity is an electronic state of matter arising from the existence of a common wave function with a coherent phase extending on a truly macroscopic scale. One major manifestation of this ... [more ▼]

Superconductivity is an electronic state of matter arising from the existence of a common wave function with a coherent phase extending on a truly macroscopic scale. One major manifestation of this striking quantum phenomenon is the dissipationless transport of electrical current, an asset deserving particular attention in the present times where the efficient energy distribution has become of utmost importance. Unfortunately, the motion of quantum units of magnetic flux (so-called vortices or fluxons), which is an unavoidable side-effect found in superconductors in the presence of transport currents and magnetic fields, severely limits the conditions to preserve dissipationless transport. This poses a challenge for achieving the functionalization of superconducting materials and threatens their spectrum of applications. It is widely known that any inhomogeneities (either material imperfections, or ones made artificially), which locally suppress superconductivity on the scale comparable to the core of the vortex, can pin the vortex and delay the onset of the vortex motion to higher applied currents. In recent years a substantial effort has been made to minimize the effects of current-induced vortex motion by tailoring arrays of artificial pinning centers. Besides improving the critical parameters of the superconducting state, a pinning matrix can be used for the manipulation of vortex matter, thus directly affecting the vortex dynamics, such as rectification of vortex motion under an ac drive (vortex diode) by introducing asymmetric pinning landscapes. In the literature one can find that the realization of the anchoring of the vortices can be based on nanostructured arrays of perforations, chemically grown defects, permanent nanomagnets, or even pinning sites produced by heavy ion bombardment. All of those realizations are based on a permanent imprint on the superconductor, without any possibility for subsequent modifications in the distribution and strength of the pinning. The principal objective of this thesis is to investigate the dynamical behavior of vortex matter under an entirely new kind of pinning landscape consisting of spatial and temporal modulation of the superconducting condensate. A particular case of spatial modulation is considered in a constricted structure where current lensing can cause extremely high vortex velocities. Subsequently, a time-dependent thermal potential introduced to the superconducting condensate will cause stroboscopic resonances during the vortex motion - a phenomenon that cannot be observed in the systems with static pinning imprints. Finally, a study of electronic gating is presented, where the local properties of superconductor, such as mean free path, or electronic band structure in general, can be influenced electronically. This is a completely unexplored interdisciplinary research topic, which will eventually allow one to manipulate individual vortices in superconducting materials by means of spatially confined and temporally controlled thermal and electromagnetic excitations. Furthermore, such techniques can provide one fundamental insight in different states of the vortex matter with respect to variation of the transport current, highly relevant for understanding the resistive state of superconducting materials and their applications. [less ▲]

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See detailDémocratie et populisme
Verjans, Pierre ULiege

Conference given outside the academic context (2017)

Le succès des candidatures populistes dans de nombreux pays depuis 2014 illustre une fragilisation de l'alignement électoral des masses observé depuis la fin de la deuxième guerre mondiale. Elle semble le ... [more ▼]

Le succès des candidatures populistes dans de nombreux pays depuis 2014 illustre une fragilisation de l'alignement électoral des masses observé depuis la fin de la deuxième guerre mondiale. Elle semble le fruit à la fois de la multiplication des moyens d'information de masse et de la désaffiliation des organisations qui avaient polarisé les systèmes politiques. [less ▲]

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See detailStudy of plant-aphid interactions in Gabonese vegetable crops and biological control perspectives
Bayendi Loudit, Sandrine ULiege

Doctoral thesis (2017)

Periurban agriculture increased vegetables production in the cities. A survey was conducted in three market gardening in Libreville and Owendo cities to register crop and pesticides diversity uses by ... [more ▼]

Periurban agriculture increased vegetables production in the cities. A survey was conducted in three market gardening in Libreville and Owendo cities to register crop and pesticides diversity uses by farmers. The most abundant cultivated species throughout the year appeared to be amaranth (Amaranthus ama L. Amaranthaceae). The most important pests were aphids (Hemiptera: Aphididae) and some beetles (Coleoptera). To control the pests, conventional neurotoxic insecticides were used with effect on environment and human health. In order to identify the occurring insects in the selected areas, a monitoring of insects was carried out during two years on amaranth, roselle, tomato (Lycopersicon esculentum M., Solanaceae) and cabbage (Brassica oleracea L., Brassicaceae). Entomological abundance and diversity were assessed through weekly trapping and visual observations from July to August each year. Insects were collected, identified at the taxonomic level of the family, and classified into three categories: pests, beneficials and associated insects to agriculture. Eighty four families belonging to height orders were recorded with 7910 and 3148 sampled individuals in 2012 and 2013 respectively. The predominant insect families were in both years Aphididae, Cecidomyiidae (Diptera) and Chrysomelidae (Coleoptera) for pests, Dolichopodidae (Diptera), Staphylinidae (Coleoptera) and Coccinellidae (Coleoptera) for beneficials, and Muscidae (Diptera), Psychodidae (Diptera) and Formicidae (Hymenoptera) for associated insects. As aphids are the most important pests, further study at species level and in relation to predatory beneficials were assessed on vegetable crops in 2013 in two periurban gardening sites. The Aphis craccivora Koch aphid was the most abundant aphid species observed infesting amaranth in both sites. The other aphid species were Lipaphis erysimi Kaltenbach, Myzus persicae Sulzer, Aphis fabae Scopoli and Aphis gossypii Glover. Moreover, seven species of natural enemies were trapped, mainly predatory hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera; Coccinellidae). A. craccivora Koch is known to be a vegetable pest. Its recent identification as pest in amaranth motivated us to study their multitrophic interactions. Since relationships between aphids and host plants could be related to symbiont and feeding behaviour. A. craccivora endosymbiont bacteria and saliva protein diversity were analysed to explain plant–aphid interactions. Indeed, Buchnera aphidicola was found. Some proteins were only identified in solid and soluble saliva, while others originated from Serratia sp. endosymbiont. Two of the identified proteins are involved in plant-pathogen interactions: calmodulin and elongation factor Tu. To control A. craccivora which causes several crop damages, volatile organic compounds (VOC) have been studied. Only aphid alarm pheromone (E)-β-farnesene (EβF) was identified and quantified. Its effect on escape behaviour in aphids has been demonstrated on three species. A. craccivora responded more strongly than the two other Aphidinae (M. persicae and A. fabae) species with 78% of the individuals initiated dispersal behavior at 500 ng dose of EβF. In another laboratory study, the repellency effect of (E)-β-farnesene, methyl salicylate and two essential oils of basil species (Ocimum gratissimum L. and Ocimum basilicum L. Lamiaceae) were determined, while no repellent effect was observed. Also, aphid populations were reduced by exposure to EβF and O. gratissimum essential oil. This study is one of the few to explore the description of insects in the market gardens of Libreville. This could contribute to the elaboration of the sustainable development strategies of pest control in the zones. [less ▲]

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See detailPascal triangles and Sierpiński gasket extended to binomial coefficients of words
Stipulanti, Manon ULiege

Conference (2017, November 29)

The binomial coefficient (u,v) of two finite words u and v (on a finite alphabet) is the number of times the word v appears inside the word u as a subsequence (or, as a "scattered" subword). For instance ... [more ▼]

The binomial coefficient (u,v) of two finite words u and v (on a finite alphabet) is the number of times the word v appears inside the word u as a subsequence (or, as a "scattered" subword). For instance, (abbabab,ab)=4. This concept naturally extends the classical binomial coefficients of integers, and has been widely studied for about thirty years (see, for instance, Simon and Sakarovitch). In this talk, I present the research lead from October 2015 on an extension of the Pascal triangles to base-2 expansions of integers. In a first part, I define two new objects that both generalize the classical Pascal triangle and the Sierpinski gasket. In a second part, I define a new sequence extracted from the Pascal triangle in base 2 and study its regularity. In a third part, I exhibit an exact formula for the behavior of the summatory function of the latter sequence. [less ▲]

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See detailMémoire de la bande dessinée dans Au travail de Olivier Josso Hamel – Cases remémorées, redessinées.
Crucifix, Benoît ULiege

in Comicalités : Études de Culture Graphique (2017)

In the first volume of Au travail (2012), Olivier Josso Hamel remembers his childhood readings of classic Franco-Belgian comics by actually redrawing those fetishized panels into the texture of his own ... [more ▼]

In the first volume of Au travail (2012), Olivier Josso Hamel remembers his childhood readings of classic Franco-Belgian comics by actually redrawing those fetishized panels into the texture of his own work. Rooted in an autobiographical approach, this quotational practice denotes a retrospective reflection on what Pierre Sterckx called the “case mémorable” (or “memorable panel”), that is fetishized panels stocked into the readers's memory. Au travail invites us to revisit the memorable panel, which is no longer limited to intimate reading memories but becomes a specific manner through which comics are citable, bound to specific aspects of “graphiation,” defining an individual and collective memory of its past. [less ▲]

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See detailHypogonadisme chez l’homme diabétique: actualités diagnostiques & thérapeutiques
VALDES SOCIN, Hernan Gonzalo ULiege

in VALDES SOCIN, Hernan Gonzalo (Ed.) RENCONTRES D’ENDOCRINOLOGIE 2017 (2017, November 25)

Résumé L’hypogonadisme chez l’homme diabétique est un syndrome clinique fréquemment sous-estimé, caractérisé par des signes et symptômes de déficience androgénique mais également par des troubles de la ... [more ▼]

Résumé L’hypogonadisme chez l’homme diabétique est un syndrome clinique fréquemment sous-estimé, caractérisé par des signes et symptômes de déficience androgénique mais également par des troubles de la fertilité. La physiopathologie de cet hypogonadisme est complexe et multifactorielle. Les troubles de la régulation glycémique, l’hyperinsulinisme et l’obésité déterminent un dysfonctionnement au niveau hypothalamique mais également au niveau gonadique. Un faisceau d’arguments nouveaux soulèvent l’intérêt de rechercher et de traiter l’hypogonadisme chez l’homme diabétique. Tout d’abord, plusieurs études épidémiologiques (1) montrent que le déficit en testostérone prédit la survenue d’un syndrome métabolique et du diabète, et que ce déficit s’accompagne d’une mortalité cardiovasculaire plus élevée (2). Ensuite, neuf études récentes démontrent que la perte pondérale intensive obtenue par régime et/ou chirurgie bariatrique normalise les taux de testostérone (3). Par ailleurs, une méta analyse portant sur cinq études confirme que la supplémentation en testostérone chez le diabétique hypogonadique se traduit par une réduction modeste de la circonférence abdominale, par une diminution de la glycémie et de l’HbA1c (4). Enfin, certaines études indiquent que la supplémentation en testostérone chez ces patients améliore leur survie (5). Si l’ensemble de ces études d’observation et d’intervention suggèrent des effets cardiométaboliques avantageux induits par la testostérone, on peut regretter un manque d’études randomisées, à large cohorte, évaluant les risques et bénéfices sur le long terme de ce traitement hormonal de supplémentation chez les patients diabétiques. Cette présentation fait le point sur les évidences actuelles reliant le déficit androgénique avec le diabète de type 2 et ses implications sur le risque cardiométabolique. [less ▲]

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See detailDébit de filtration glomérulaire : estimations et mesures
DELANAYE, Pierre ULiege

Scientific conference (2017, November 24)

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See detailModelling ice flow for large-scale ice-sheet simulations
Bulthuis, Kevin ULiege; Arnst, Maarten ULiege; Pattyn, Frank

Diverse speeche and writing (2017)

General introduction to ice-flow modelling for ice-sheet simulations

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See detailCiné-débat: Merci pour la pluie
Wellens, Joost ULiege

Conference given outside the academic context (2017)

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See detailIsolation and characterization of nanocelluloses from wheat straw and their application in agricultural water-saving materials
Liu, Qi ULiege

Doctoral thesis (2017)

Humans have been cultivating land for approximately 12,000 years. As such, most countries worldwide have considered crop waste as a global issue linked with environmental protection, economic development ... [more ▼]

Humans have been cultivating land for approximately 12,000 years. As such, most countries worldwide have considered crop waste as a global issue linked with environmental protection, economic development, and healthy living. Many varieties of straw are produced all over China in massive quantities (more than 900 million tons per year). Although banned by the government, stubble burning is widely applied by Chinese farmers as an easy and cheap way to remove stalks after harvests. However, this practice significantly contributes to China’s carbon dioxide emissions and health risks associated with the thick mists it produces. As a renewable biomass resource, straw can be used to make new marketable materials, but its full potential has yet to be realized. Thus, future studies should be directed toward the isolation and rational use of agricultural waste. In addition to the pollution caused by agricultural waste, water shortage, particularly in northern and northwestern China, severely hinders agricultural production. This region accounts for half of the total surface of China but has less than 20% of the total national available water resources. Despite the severity of the water shortage in this region, the efficiency of irrigation water use is only 40%. Many strategies have been applied to promote a water-saving agriculture. One such strategy is the use of water-saving materials, such as plastic mulching films and superabsorbent polymers. However, these two materials are non-biodegradable, and their mechanical properties are unsatisfactory. A systematic analysis of the literature revealed that agricultural waste is a cheap and promising source of raw materials that could be used to obtain cellulose and nanocelluloses. Nanocelluloses can be used for the industrial production of super-strong but lightweight nanocomposite materials. The first step involved the isolation of cellulose, cellulose nanocrystallines (CNCs), and cellulose nanofibers (CNFs) from wheat straw. First, four CNCs were isolated from four commercial microcrystalline celluloses (MCCs) through sulfuric acid hydrolysis. The effects of the characteristics of the MCC on the morphology, structure, and properties of the resulting CNCs were assessed. The results revealed that both particle size and dispersity influenced the isolated CNCs. Second, cellulose was isolated from wheat straw through a microwave-assisted chemical treatment process that reduced chemical use. The reaction conditions and promoting effect of microwave on the resulting fibers were investigated. The results indicated that temperature played the most important role in cellulose isolation, and that microwave can reduce either the reaction time or the chemical use during the microwave-assisted alkali hydrolysis process. High-purity (94%) CNFs were isolated from wheat straw through an environmentally friendly, multi-step treatment process that combined steam explosion, microwave-assisted hydrolysis, and microfluidization. Chemical identification and characterization were performed to study the effect of each treatment step and investigate the potential utilization of CNFs in nanocomposites. Chemical analysis showed that the cellulose content increased from 44.81% to 94.23%, whereas the hemicellulose and lignin contents significantly decreased from 33.41% and 8.75% to 5.54% and 1.68%, respectively. Long and loose 10–40 nm wide nanofiber bundles and an entangled network of cellulose fibers with an average individual diameter of 5.42 nm were observed during this eco-friendly process. In the last part of this study, nanocelluloses were introduced into superabsorbent polymers and mulching films used in agriculture to improve their performance. The effects of nanocelluloses on their structure, properties, and mechanical performance were investigated. First, superabsorbent polymers of acrylamide–acrylate copolymers and others with CNFs, CNCs, or MCC were synthesized. The swelling capacities in pure water and in various solutions, the capacities for repeated water absorption, the water-retaining capacities in soil, and the mechanical properties of the hydrogels were compared. The results revealed that the 3D structures of the acrylamide–acrylate–CNF and acrylamide–acrylate–CNC hydrogels were strengthened by the nanocellulose. These two polymers exhibited excellent capacities for repeated water absorption. By contrast, the biodegradable agricultural mulching film did not present satisfying mechanical and barrier properties as an alternative for ordinary polyethylene film. In this thesis, CNC was introduced into the film of poly (butyleneadipate-co-terephthalate) /polylactic acid composites. Poly(butyleneadipate-co-terephthalate)/polylactic acid/CNC films with various contents of CNC were prepared, characterized, and tested as for their properties. Compared with the film without CNC, poly (lactic acid) / poly (butylene-adipate-co-terephtalate)/3% CNC film showed an increased deformation by 188.80%. The barrier performance of the films increased with increasing CNC content. However, the tensile properties decreased when the CNC content exceeded 3%. Both the mechanical and barrier properties were promoted. These results highlighted that (i) wheat straw is a cellulose-rich natural resource of CNF and CNC; (ii) microwave can reduce either the reaction time or the chemical use during the cellulose-isolation process; (iii) high-purity CNF could be obtained through an environmentally friendly method; and (iv) nanocellulose could improve the mechanical properties of both superabsorbent polymers and mulching films, and enhance their performances in agricultural applications. In a broader perspective, microwave and other techniques should be further explored in the context of green isolation processes. Agricultural biomass natural fiber-based composites must be further investigated to maximize their applications. Approaches that could offer significant cost savings for the industrial production of nanocellulose and new nanocellulose-based materials should be developed further. We aim to promote the research interest for the isolation and application of agricultural-waste-based nanocellulose, which deserve further research and documentation. This thesis is only the beginning of a greater endeavor. [less ▲]

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See detailFive years of harvest with the vortex coronagraph
Absil, Olivier ULiege

Scientific conference (2017, November 24)

While the concept of vortex coronagraphy dates back to 2005, the first science-grade Annular Groove Phase Masks (AGPM), working in the thermal infrared regime, have been installed at the VLT only in 2012 ... [more ▼]

While the concept of vortex coronagraphy dates back to 2005, the first science-grade Annular Groove Phase Masks (AGPM), working in the thermal infrared regime, have been installed at the VLT only in 2012. They are now also equipping the Keck telescope and the Large Binocular Telescope, and will soon be at the core of more ground-based high-contrast imaging instruments. In this seminar, I will shortly review the technology development undertaken over the last 12 years, and describe the on-sky operations and performance of the vortex coronagraph. I will then present the main scientific results obtained since 2012, and explain how we have recently adapted deep learning techniques to the problem of post-processing in high-contrast imaging. I will finally discuss the perspectives with new instruments, including the Breakthrough Watch project. [less ▲]

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See detailInvasive plants as potential food resource for native pollinators: A case study with two invasive species and a generalist bumble bee
Drossart, Maxime; Michez, Denis; Vanderplanck, Maryse ULiege

in Scientific Reports (2017)

It is now well established that invasive plants may induce drifts in the quantity and/or quality of floral resources. They are then often pointed out as a potential driver of bee decline. However, their ... [more ▼]

It is now well established that invasive plants may induce drifts in the quantity and/or quality of floral resources. They are then often pointed out as a potential driver of bee decline. However, their impact on bee population remains quite unclear and still controversial, as bee responses are highly variable among species. Here, we compared the amino acid composition of pollen from three native and two invasive plant species included in diets of common pollinators in NW Europe. Moreover, the nutritional intake (i.e., pollen and amino acid intakes) of Bombus terrestris colonies and the pollen foraging behaviour of workers (i.e., visiting rate, number of foraging trips, weight of pollen loads) were considered. We found significant differences in pollen nutrients among the studied species according to the plant invasive behaviour. We also found significant differences in pollen foraging behaviour according to the plant species, from few to several foraging trips carrying small or large pollen loads. Such behavioural differences directly impacted the pollen intake but depended more likely on plant morphology rather than on plant invasive behaviour. These results suggest that common generalist bumble bees might not always suffer from plant invasions, depending on their behavioural plasticity and nutritional requirements. [less ▲]

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See detailEnjeux de gouvernance métropolitaine et fragmentation territoriale
Breuer, Christophe ULiege

Conference (2017, November 24)

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See detailDans quelle mesure l’apprentissage en milieu universitaire chez les étudiants sportifs de haut niveau peut-il être étayé par un dispositif techno-pédagogique ?
Bonni, Jérémy ULiege; Cloes, Marc ULiege; Denis, Brigitte ULiege

Conference (2017, November 24)

Les étudiants sportifs qui pratiquent un sport à haut niveau, tout en poursuivant des études supérieures, sont amenés à manquer fréquemment les cours. Ceci engendre un certain nombre de problèmes ... [more ▼]

Les étudiants sportifs qui pratiquent un sport à haut niveau, tout en poursuivant des études supérieures, sont amenés à manquer fréquemment les cours. Ceci engendre un certain nombre de problèmes, notamment sur le plan temporel et organisationnel (Mc Kenna & Dustan-Lewis, 2004 ; Javerlhiac, Leyondre & Bodin, 2011). Différentes solutions sont proposées, telles que l’encadrement personnalisé par un tuteur académique, l’accompagnement d’un coordinateur, des avantages pédagogiques, des modalités spécifiques d’évaluations et d'enseignement, dont la formation à distance, et l’accès à un réseau d’étudiants sportifs. La formation à distance est en outre une solution envisagée dans différents pays (Cloes, Lenzen & Polis, 2007 ; Capranica & Guidotti, 2016). Qu’en est-il des étudiants sportifs de l’Université de Liège (ULiège) et de leurs encadrants ? Selon Namurois (2016), le recours aux TICE et aux activités/ressources en ligne sont rares chez les enseignants de l’ULiège qui s’adressent à ce type d’étudiants. Or, l’exploitation des Technologies de l’Information et de la Communication à des fins d’Enseignement (TICE) peut contribuer à construire des situations d’apprentissage qui favorisent l’atteinte des objectifs de formation, en utilisant des outils et des modes d’étayage spécifiques. Au vu de ce qui est déjà proposé à l’ULiège, s’agirait-il d’une solution permettant d’étayer l’apprentissage de ces étudiants spécifiques ? Si oui, à quelles conditions devra être soumise l’implémentation de dispositifs techno-pédagogiques au sein de cette même université ? Différents points de passages obligés (Hussenot, 2007) pouvant favoriser cette implémentation devront être identifiés et négociés. Dans le cadre de cette recherche, une analyse de l’existant et des besoins sera tout d’abord réalisée selon une approche systémique en tenant compte de divers actants (enseignants, étudiants sportifs, instances de l’ULiège, ressources, etc.). Des entretiens semi-structurés seront entrepris pour dresser la cartographie des acteurs et identifier les actions et structures déjà mises en place à l’ULiège, de même que dans d’autres universités. Parallèlement à ces entretiens, un questionnaire sera adressé aux étudiants sportifs et à leurs enseignants afin d’analyser et confronter leurs besoins en matière d’apprentissage/enseignement. L’analyse des résultats permettra également de dégager des actions potentielles de soutien à l’apprentissage qu’il serait opportun de proposer ultérieurement. Cette communication porte sur la présentation de la problématique et de la méthodologie suivie dans le cadre de cette future recherche ainsi que sur les résultats d’une première analyse des besoins réalisée auprès des étudiants sportifs de l’Université de Liège de juin à novembre 2017. [less ▲]

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See detailTrophic ecology of icefishes (Notothenioidei, Perciformes) in a context of climate change
Peignot, Quentin; Frederich, Bruno ULiege; Lepoint, Gilles ULiege et al

Poster (2017, November 23)

The Southern Ocean currently undergoes major environmental modifications related to climate change. When faced with environmental changes, all organisms are expected to have some intrinsic capacity to ... [more ▼]

The Southern Ocean currently undergoes major environmental modifications related to climate change. When faced with environmental changes, all organisms are expected to have some intrinsic capacity to adapt their ecological habits to their new life conditions. Currently, biological traits of many Antarctic species are still unknown and we need such information to assess their capacity to adapt to natural and anthropogenic perturbations. Notothenioidei (Perciformes), or icefishes, are endemic to the Southern Ocean and they are an important trophic component of these marine ecosystems. Here we used stable isotopes ratios of carbon (δ13C) and nitrogen (δ15N) of two well represented genera of icefishes (Trematomus and Lepidonotothen) sampled in 2002/2004 and/or in 2015/2016 to better understand their resources partitioning and the influence of environmental changes on their trophic ecology. Isotopic niches (which are a proxy of the realized ecological niches) were modeled using the SIBER (Stable Isotope Bayesian Ellipses in R) R-package. Our results revealed a great variation in isotopic compositions among icefishes, suggesting that they exploit a wide array of resources. The overlap between the isotopic niches of Trematomus and Lepidonotothen genera in 2002/2004 highlights a possible past competition for resources. Moreover, temporal evolution of niches suggests taxon-specific ecological plasticity in response to variation in environmental parameters and/or in prey availability. An increase in resources partitioning between the two genera was observed over the studied period. In the future, it would be interesting to use mixing models including isotopic composition of potential preys to identify possible changes in their trophic ecology. [less ▲]

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