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Atelier Nitrate-Eau. Evaluation du Programme de Gestion Durable de l'Azote. (2010)Detailed reference viewed: 25 (8 ULiège) L'isotope stable 15Net le lysimètre, des outils complémentaires pour l'étude de la lixiviation de l'azote dans les sols agricolesDestain, Jean-Pierre ; Fonder, Nathalie; Xanthoulis, Dimitri et alin Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(S1), 91-96L’isotope stable 15N a été utilisé dans des expérimentations en cases lysimétriques visant à étudier la lixiviation de l’azote dans les sols agricoles. À Gembloux, un apport de nitrate l’ammoniaque ... [more ▼]L’isotope stable 15N a été utilisé dans des expérimentations en cases lysimétriques visant à étudier la lixiviation de l’azote dans les sols agricoles. À Gembloux, un apport de nitrate l’ammoniaque présentant une abondance isotopique de 2,161 At%15N a été appliqué à raison de 200 kg N.ha-1 dans deux lysimètres, avant une culture d’épinard suivie de haricot et d’un froment d’hiver. La récupération de l’azote par les cultures a été de 39,8 % dans le premier lysimètre et de 62,2 % dans le second. Les concentrations en azote nitrique des eaux percolées du second ont été constamment plus élevées que dans le premier, probablement à cause d’une moindre immobilisation microbienne. À Remicourt et Omal, un reliquat de 150 kg N.ha-1 (simulé par un apport de 15NH4 15NO3 en automne) a complètement disparu du profil du sol (0-90 cm) dès juillet de l’année suivante. Une culture de froment d’hiver à Omal n’a récupéré qu’environ 9 % de l’azote apporté à l’automne. La mesure de la teneur en azote nitrique des eaux percolées a montré des valeurs nettement plus élevées à Remicourt (jusqu’à plus de 70 mg N.l-1) suite à un apport important de compost riche en azote, qu’à Omal. L’isotope 15N n’a pu être détecté dans aucune des eaux lysimétriques, probablement par un manque de sensibilité de l’appareil. [less ▲]Detailed reference viewed: 97 (1 ULiège) Isotopic abundance in the CN coma of comets: Ten years of measurementsSchulz, R.; Jehin, Emmanuel ; Manfroid, Jean et alin Planetary and Space Science (2008), 56Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining ... [more ▼]Over the past 10 years the isotopic ratios of carbon ([SUP]12[/SUP]C/[SUP]13[/SUP]C) and nitrogen ([SUP]14[/SUP]N/[SUP]15[/SUP]N) have been determined for a dozen comets, bright enough to allow obtaining the required measurements from the ground. The ratios were derived from high-resolution spectra of the CN coma measured in the B[SUP]2[/SUP]â [SUP]+[/SUP]â X[SUP]2[/SUP]â [SUP]+[/SUP] (0, 0) emission band around 387 nm. The observed comets belong to different dynamical classes, including dynamically new as well as long- and short-period comets from the Halley- and Jupiter-family. In some cases the comets could be observed at various heliocentric distances. All values determined for the carbon and nitrogen isotopic ratios were consistent within the error margin irrespective of the type of comet or the heliocentric distance at which it was observed. Our investigations resulted in average ratios of [SUP]12[/SUP]C/[SUP]13[/SUP]C=91Â±21 and nitrogen [SUP]14[/SUP]N/[SUP]15[/SUP]N=141Â±29. Whilst the value for the carbon isotopic ratio is in good agreement with the solar and terrestrial value of 89, the nitrogen isotopic ratio is very different from the telluric value of 272. [less ▲]Detailed reference viewed: 33 (2 ULiège) Isotopic abundance of nitrogen and carbon in distant cometsManfroid, Jean ; Jehin, Emmanuel ; Hutsemekers, Damien et alin Astronomy and Astrophysics (2005), 432(Letters), 5-8The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios have been determined in comets C/1995 O1 (Hale-Bopp), C/2001 Q4 ... [more ▼]The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios have been determined in comets C/1995 O1 (Hale-Bopp), C/2001 Q4 (NEAT) and C/2003 K4 (LINEAR) at heliocentric distances of, respectively, 2.7, 3.7 and 2.6 AU. These ratios have also been measured at rË 1 AU. No significant differences were found between all determinations, nor with the value obtained for other comets. If confirmed, the discrepancy between the nitrogen isotopic ratios from optical and millimeter measurements on CN and HCN would rule out HCN as a major parent of the cometary CN radicals. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programmes 270.C-5043, 073.C-0525 and 274.C-5015). [less ▲]Detailed reference viewed: 21 (1 ULiège) Isotopic abundances of carbon and nitrogen in Jupiter-family and Oort Cloud cometsHutsemekers, Damien ; Manfroid, Jean ; Jehin, Emmanuel et alin Astronomy and Astrophysics (2005), 440(Letters), 21-24The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P ... [more ▼]The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P/1981 Q1 Howell, and in the chemically peculiar Oort Cloud comet C/1999 S4 (LINEAR). By comparing these measurements to previous ones derived for six other Oort Cloud comets (including one of Halley-type), we find that both the carbon and nitrogen isotopic ratios are constant within the uncertainties. The mean values are [SUP]12[/SUP]C/[SUP]13[/SUP]C ~= 90 and [SUP]14[/SUP]N/[SUP]15[/SUP]N ~=145 for the eight comets. These results strengthen the view that CN radicals originate from refractory organics formed in the protosolar molecular cloud and subsequently incorporated in comets. [less ▲]Detailed reference viewed: 18 (1 ULiège) Isotopic and geochemical constraints on the evolution of the Mazury granitoids (NE Poland)Baginski, Boguslaw; Duchesne, Jean-Clair ; Martin, Hervé et alin Koslowski, A.; Wiszniewska, Janina (Eds.) Granitoids in Poland (2007)Detailed reference viewed: 20 (1 ULiège) Isotopic Composition and sources of Organic Carbon Pools within the Tana River Basin, (Kenya)Tamooh, F.; Van Den Meersche, K.; Borges, Alberto et alPoster (2011)Detailed reference viewed: 22 (1 ULiège) Isotopic composition of nitrogen species in groundwater under agricultural areas: A reviewNikolenko, Olha ; Jurado Elices, Anna ; Borges, Alberto et alin Science of the Total Environment (2017)This work reviews applications of stable isotope analysis to the studies of transport and transformation of N species in groundwater under agricultural areas. It summarizes evidence regarding factors ... [more ▼]This work reviews applications of stable isotope analysis to the studies of transport and transformation of N species in groundwater under agricultural areas. It summarizes evidence regarding factors affecting the isotopic composition of NO3−, NH4+ and N2O in subsurface, and discusses the use of 11B, 18O, 13C, 34S, 87Sr/86Sr isotopes to support the analysis of δ15N values. The isotopic composition of NO3−, NH4+ and N2O varies depending on their sources and dynamics of N cycle processes. The reported δ15N-NO3− values for sources of NO3− are: soil organic N – +3‰–+8‰, mineral fertilizers – −8‰–+7‰; manure/household waste – +5‰ to +35‰. For NH4+ sources, the isotopic signature ranges are: organic matter – +2.4–+4.1‰, rainwater – −13.4–+2.3‰, mineral fertilizers –−7.4–+5.1‰, householdwaste –+5–+9‰; animalmanure–+8–+11‰. ForN2O, isotopic composition depends on isotopic signatures of substrate pools and reaction rates. δ15Nvalues of NO3− are influenced by fractionation effects occurring during denitrification (ɛ=5–40‰), nitrification (ɛ=5–35‰) and DNRA (ɛ not reported). The isotopic signature of NH4+ is also affected by nitrification and DNRA as well as mineralization (ɛ=1‰), sorption (ɛ=1–8‰), anammox (ɛ=4.3–7.4‰) and volatilization (ɛ=25‰). As for theN2O, production of N2O leads to its depletion in 15N, whereas consumption – to enrichment in 15N. The magnitude of fractionation effects occurring during the considered processes depends on temperature, pH, DO, C/NO3− ratio, size of the substrate pool, availability of electron donors, water content in subsoil, residence time, land use, hydrogeology. While previous studies have accumulated rich data on isotopic composition of NO3− in groundwater, evidence remains scarce in the cases of NH4+ and N2O. Further research is required to consider variability of δ15N-NH4+ and δ15N-N2O in groundwater across agricultural ecosystems. [less ▲]Detailed reference viewed: 64 (23 ULiège) Isotopic compositions of North Sea marine mammalsDamseaux, France ; Pomeroy, Paddy; Sierbert, Ursula et alPoster (2017)For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test the potential ... [more ▼]For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses on marine mammals sampled in the North Sea to test the potential impact of changes in fish stocks on feeding behaviour of grey seals, harbour seals and harbour porpoises. Data included δ13C and δ15N values measured in blood cells and muscles from the three species. SIBER, an isotopic niche quantification approach, is used to highlight potential dietary similarity and thus competition between marine mammal species. Harbour seals sampled in Germany showed the highest δ15N values, reflecting a trophic position at the top of the food web, alongside grey seals. In contrast, harbour porpoises sampled from Germany displayed the lowest trophic position. The ellipse overlapping between German harbour and grey seals was very important, showing similarity in, and therefore potential competition for, food sources. On the other hand, the harbour seal and the harbour porpoise of Germany displayed extended ellipse size compared to the grey seal. This may be due to a more diverse diet and, perhaps, a more opportunistic foraging behaviour than grey seals. Surprisingly, another group of grey seals sampled at Isle of May, Scotland displayed lower δ15N values and a very small ellipse size compared to grey seals from Germany, presumably being even more selective in their prey choice. Nevertheless, comparing the trophic position of the groups of grey seals requires caution as the isotopic baseline differed between the two sampling areas. This study allowed the determination of the competition, the spatial variations and the trophic niches of marine mammals in the North Sea and will, at the end, evaluate the effects of the changes in the North Sea on the ecology of marine mammals. [less ▲]Detailed reference viewed: 49 (1 ULiège) Isotopic constraints on the Cenozoic evolution of the carbon cycleFrançois, Louis ; Godderis, Y.in Chemical Geology (1998), 145(3-4), 177-212In the last few years, several models have been built to explore the Cenozoic evolution of the carbon and strontium cycles. Of particular interest is the study of the impact on the carbon cycle of major ... [more ▼]In the last few years, several models have been built to explore the Cenozoic evolution of the carbon and strontium cycles. Of particular interest is the study of the impact on the carbon cycle of major mountain uplifts such as the Himalayan orogeny. To explain the Cenozoic increase in the measured seawater strontium isotopic ratio, it was recently proposed that the Himalyan uplift could be responsible for an enhanced consumption of atmospheric CO2 by continental silicate weathering. Here, a new model of the carbon cycle evolution over Cenozoic times is presented. It calculates the various fluxes involved in the organic and inorganic components of the carbon cycle from the seawater delta C-13, the biological isotopic fractionation in the ocean and the seafloor spreading rate. The model equilibrates the budgets of the carbon and alkalinity cycles on the million year timescale, assuming as many previous investigators that the system remains close to equilibrium. The validity of this equilibrium approximation is examined critically. Various sensitivity experiments are performed in order to test the impact of the model parameters on the results. The calculated history of the carbonate deposition rate is consistent with the available reconstruction. The continental silicate weathering rate calculated by the model appears to be widely insensitive to the model parameters, showing three distinct evolutions over the Cenozoic. The model indeed suggests a time of relative constancy of the silicate weathering flux before 40 Ma, followed by a period of slow decrease until 15 Ma and finally a marked increase up to the present. In a progressively cooler world, this evolution may be interpreted as a change from a 'chemically' controlled to a 'physically' controlled weathering regime. The evolution of continental silicate weathering thus partly appears decoupled from the increase in the observed seawater strontium isotopic ratio. For this reason, the evolution of the calculated riverine Sr-87/ Sr-86 ratio shows a strong increase over the Cenozoic, from about 0.710 to 0.712. However, this increase may largely be reduced by considering the recycling of a pelagic carbonate reservoir increasing over the Cenozoic or by assuming that seafloor basalt weathering is a CO2- or climate-dependent process. (C) 1998 Elsevier Science B.V. All rights reserved. [less ▲]Detailed reference viewed: 30 (1 ULiège) Isotopic constraints on the genesis of the anorthosite suite of rocksDemaiffe, Daniel; Weis, Dominique; Michot, Jean et alin Chemical Geology (1986), 57Detailed reference viewed: 27 (1 ULiège) Isotopic half-life and enrichment factor in two species of European freshwater fish larvae: an experimental approachLatli, Adrien; Sturaro, Nicolas ; Dujardin, Nelson et alin Rapid Communications in Mass Spectrometry (2017), 31(8), 685-692RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue ... [more ▼]RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue enrichment factor (TEF) and half-life (HL). We experimentally compared TEF and HL in two freshwater fish larvae. We hypothesised that chub had a better growth/tissue replacement ratio than roach, due to the use of a food closer to their natural diet. METHODS: We determined the isotopic HL, the TEF and the contribution of growth or metabolic tissue replacement to dynamic isotopic incorporation. After yolk sac resorption, larvae were fed for 5 weeks with prey similar to their natural diet (Artemia nauplii) up to the isotopic equilibrium followed by Chironomid larvae. Stable isotope measurements were carried out using a continuous flow isotope ratio mass spectrometer coupled to an elemental analyser. RESULTS: Changes in isotopic composition strongly followed the predictions of exponential growth and time-dependent models. The isotopic HL varied between 8.2 and 12.6 days and the TEF of nitrogen and carbon ranged from 1.7 to 2.1‰ and from –0.9 to 1.2 ‰, respectively. The incorporation of dietary 13C was due more to the production of new tissue (between 56 and 79%) than to the metabolic process. Chub allocated more energy to growth than roach and the Chironomidae diet contributed more to the consumers’ growth than the Artemia diet. CONCLUSIONS: Metabolic rates seemed lower for chub than for roach, especially when they were fed with Chironomidae. A Chironomidae-based diet would be more profitable to chub, and the high associated growth rate could increase the development of the fish larvae. The HL and TEF were in the range of those reported in the literature. These results will be helpful for field-based studies, because they can help to increase the accuracy of models. [less ▲]Detailed reference viewed: 36 (8 ULiège) Isotopic niches of Fin Whales from the Mediterranean Sea and the Celtic sea (North Atlantic)Das, Krishna ; Holleville, Ophélie; Ryan, Conor et alin Marine Environmental Research (2017), 127The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the ... [more ▼]The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology. The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). δ13C and δ15N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea. δ13C and δ15N values ranged from -20.4 to -17.1 ‰ and from 5.9 to 8.9 ‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences. One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts. [less ▲]Detailed reference viewed: 40 (14 ULiège) Isotopic ratios and elemental contents as indicators of seagrass C processing and sewage influence in a tropical macrotidal ecosystem (Madagascar, Mozambic channel)Lepoint, Gilles ; Frederich, Bruno ; Gobert, Sylvie et alin Scientia Marina (2008), 72(1), 109-117Isotopic ratios and elemental concentrations of carbon and nitrogen were measured in seven seagrass species colonising different tidal flats near Toliara (SW Madagascar) in order to determine the ... [more ▼]Isotopic ratios and elemental concentrations of carbon and nitrogen were measured in seven seagrass species colonising different tidal flats near Toliara (SW Madagascar) in order to determine the potential use of these parameters for assessing C processing and sewage use by tropical seagrasses. Nitrogen concentrations measured in upper intertidal seagrasses near Toliara were almost twice those measured on the tidal flat near a healthy mangrove situated 20 km away from Toliara town. At Toliara Beach, δ15N values were correlated with the N concentrations of Halodule sp., one of the dominant species on the tidal flat. This correlation did not exist for Halophila ovalis, the other dominant species. An increase in N concentrations and δ15N values demonstrates the influence of sewage coming directly onto Toliara Beach on the N cycles of intertidal seagrasses. Nevertheless, this influence seems restricted to the upper littoral zone and was not the main cause of seagrass die-off. On the other hand, at the mangrove site, δ15N values were not correlated with the N concentrations of Halodule sp. or Thalassia hemprichii, showing that natural δ15N variability is driven by other factors than the δ15N of N sources. Moreover, inter-individual variability of δ15N values was greater than inter-specific or inter-site variability, making the δ15N difficult to interpret in the context of human-disturbance influence on the N cycle of tropical seagrasses. δ13C values were close to -9‰, indicating the use of HCO 3– as an inorganic carbon source by the seven investigated species. Contrary to our hypothesis, variation between sites and location on the tidal flat was limited, suggesting limited impact on δ13C values of sewage, emersion duration and mechanisms for HCO 3– incorporation. [less ▲]Detailed reference viewed: 106 (23 ULiège) Isotopic Ratios in a Peculiar Outbursting CometYang, Bin; Hutsemekers, Damien ; Shinnaka, Yoshiharu et alin Bulletin of the American Astronomical Society (2017, October 01), 49Isotopic ratios in comets provide keys for the understanding of the origin of cometary material, and the physical and chemical conditions in the early Solar Nebula. A newly discovered peculiar comet, C ... [more ▼]Isotopic ratios in comets provide keys for the understanding of the origin of cometary material, and the physical and chemical conditions in the early Solar Nebula. A newly discovered peculiar comet, C/2015 ER61, underwent an outburst with a total brightness increase of 2 magnitudes on the night of April 4th, 2017. The sharp increase in brightness offers a rare opportunity to measure the isotopic ratios of the light elements of this comet. We obtained two high-resolution spectra of C/2015 ER61 with UVES on Apr. 13 and Apr. 17 respectively. At the time of our observations, the comet was fading gradually since the outburst. We measured the 12C/13C and 14N/15N isotopic ratios from the CN Violet (0,0) band. In addition, we determined the 14N/15N ratio in NH2 for C/2015 ER61 from four pairs of NH2 isotopologue lines. Some 18OH lines were detected but the S/N of these lines is too low to derive a reliable 18O/16O estimate. We will present our UVES spectra of C/2015 ER61, obtained shortly after the outburst. We will also present the comparison of the Isotopic ratios of C/2015 ER61 with those of other comets. [less ▲]Detailed reference viewed: 18 (1 ULiège) Isotopic Ratios in Comets: Status and PerspectivesJehin, Emmanuel ; Manfroid, Jean ; Hutsemekers, Damien et alin Earth, Moon, and Planets (2009), 105Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13 ... [more ▼]Isotopic abundance ratios are excellently suited to probe the origin of solar system matter. We review the recent measurements of the isotopic ratios of the light elements (D/H, [SUP]12[/SUP]C/[SUP]13[/SUP]C, [SUP]16[/SUP]O/[SUP]18[/SUP]O, [SUP]14[/SUP]N/[SUP]15[/SUP]N, [SUP]32[/SUP]S/[SUP]34[/SUP]S) in cometary dust and gas and discuss briefly their implications. Special emphasis will be put on the determinations and progress performed in the field over the past years thanks to high resolution spectroscopy of cometary comae obtained with the ESO Very Large Telescope. Future perspectives from space missions and ground-based observations with new large and extremely large telescopes operating in the optical, infrared and submillimeter wavelengths will be presented. [less ▲]Detailed reference viewed: 20 (6 ULiège) Isotopic ratios in outbursting comet C/2015 ER61Yang, Bin; Hutsemekers, Damien ; Shinnaka, Yoshiharu et alin Astronomy and Astrophysics (2018), 609Isotopic ratios in comets are critical to understanding the origin of cometary material and the physical and chemical conditions in the early solar nebula. Comet C/2015 ER61 (PANSTARRS) underwent an ... [more ▼]Isotopic ratios in comets are critical to understanding the origin of cometary material and the physical and chemical conditions in the early solar nebula. Comet C/2015 ER61 (PANSTARRS) underwent an outburst with a total brightness increase of 2 magnitudes on the night of 2017 April 4. The sharp increase in brightness offered a rare opportunity to measure the isotopic ratios of the light elements in the coma of this comet. We obtained two high-resolution spectra of C/2015 ER61 with UVES/VLT on the nights of 2017 April 13 and 17. At the time of our observations, the comet was fading gradually following the outburst. We measured the nitrogen and carbon isotopic ratios from the CN violet (0, 0) band and found that [SUP]12[/SUP]C/[SUP]13[/SUP]C = 100 ± 15, [SUP]14[/SUP]N/[SUP]15[/SUP]N = 130 ± 15. In addition, we determined the [SUP]14[/SUP]N/[SUP]15[/SUP]N ratio from four pairs of NH[SUB]2[/SUB] isotopolog lines and measured [SUP]14[/SUP]N/[SUP]15[/SUP]N = 140 ± 28. The measured isotopic ratios of C/2015 ER61 do not deviate significantly from those of other comets. [less ▲]Detailed reference viewed: 7 (1 ULiège) Isotopic ratios in outbursting comet C/2015 ER61Yang, Bin; Hutsemekers, Damien ; Shinnaka, Yoshiharu et alE-print/Working paper (2017)Isotopic ratios in comets are critical to understanding the origin of cometary material and the physical and chemical conditions in the early solar nebula. Comet C/2015 ER61 (PANSTARRS) underwent an ... [more ▼]Isotopic ratios in comets are critical to understanding the origin of cometary material and the physical and chemical conditions in the early solar nebula. Comet C/2015 ER61 (PANSTARRS) underwent an outburst with a total brightness increase of 2 magnitudes on the night of 2017 April 4. The sharp increase in brightness offered a rare opportunity to measure the isotopic ratios of the light elements in the coma of this comet. We obtained two high-resolution spectra of C/2015 ER61 with UVES/VLT on the nights of 2017 April 13 and 17. At the time of our observations, the comet was fading gradually following the outburst. We measured the nitrogen and carbon isotopic ratios from the CN violet (0,0) band and found that $^{12}$C/$^{13}$C=100 $\pm$ 15, $^{14}$N/$^{15}$N=130 $\pm$ 15. In addition, we determined the $^{14}$N/$^{15}$N ratio from four pairs of NH$_2$ isotopolog lines and measured $^{14}$N/$^{15}$N=140 $\pm$ 28. The measured isotopic ratios of C/2015 ER61 do not deviate significantly from those of other comets. [less ▲]Detailed reference viewed: 8 (0 ULiège) Isotopic tracing of sediment components that are assimilated by epibiontic juveniles of Holothuria scabra (Holothuroidea)Plotieau, Thomas; Lepoint, Gilles ; Lavitra, Thiery et alin Journal of the Marine Biological Association of the United Kingdom (2014), 94(7), 1485-1490Despite H. scabra’s wide distribution and status as one of the best candidates for sustaining the development of tropical sea cucumber aquaculture, very few data are available regarding the organic ... [more ▼]Despite H. scabra’s wide distribution and status as one of the best candidates for sustaining the development of tropical sea cucumber aquaculture, very few data are available regarding the organic fraction it assimilates in practice. In this study we report experimental results where H. scabra’s diet was supplemented with various 15N-labelled organic fractions of sediment. We used juveniles weighing between 38- 88 mg at the beginning of the experiment (ca. 2 cm long and 30 days old). Their growth was measured over a four week period and their 15N composition recorded. The results showed that H. scabra juveniles assimilated all added organic components from both dissolved and particulate fractions of the sediment. Bacteria seem to be an important food source for juveniles, even more so than microphytobenthos (diatoms). [less ▲]Detailed reference viewed: 71 (10 ULiège) Isotopic turnover and trophic fractionation in two species of European freshwater fishes: an experimental approachLatli, Adrien; Sturaro, Nicolas ; Michel, Loïc et alPoster (2016, September 05)Detailed reference viewed: 20 (2 ULiège)