Borges, Alberto

Das, Krishna

Dauby, Patrick

Gobert, Sylvie

Lepoint, Gilles

Mascart, Thibaud

Michel, Loïc

Remy, François

Sturaro, Nicolas

Ghent University Academic Bibliography

Applications of stable isotopes in environmental  studies at the University of Liege Sturaro N1, Borges A V2, Das K1, Dauby P3, Gobert S1, Mascart T1, Michel L1, Remy F1 and Lepoint G1 1. Laboratory of Oceanology - MARE Centre - University of LIEGE - B6C - 4000 LIEGE - Sart Tilman - Belgium 2. Chemical Oceanography Unit - MARE Centre - University of LIEGE - B5 - 4000 LIEGE - Sart Tilman - Belgium 3. Laboratory of Animal Systematic and Diversity - MARE Centre - University of LIEGE - B6C - 4000 LIEGE - Sart Tilman - Belgium Since at least 30 years, at Prof Dauby initiative, applications of stable isotopes in marine ecosystems have been developed at University of Liege within the Laboratory of Oceanology and, more  recently, within the Chemical Oceanography Unit. One research axis is the measurement  of stable isotope compositions (C, N, S) in organic matter to delineate trophic web  structure and study animal diet, their trophic niches and their alteration by human  activities. Coupling between trophic ecology and ecotoxicology, as well as  the study of biogeochemical processes are other areas of investigation.        Contacts: Dr. G. Lepoint (G.Lepoint@ulg.ac.be); Dr. N. Sturaro (nicolas.sturaro@ulg.ac.be) Publications: http://www2.ulg.ac.be/oceanbio/Publications.html Studying trophic ecology Coupling trophic ecology and ecotoxicology Studying biogeochemistry Our equipment  The Laboratory of Oceanology Left: EA-GC-C-IRMS-MSD (Isoprine, Elementar, Agilent) of the Laboratory of Oceanology In 2014, the unit has acquired an off-axis cavity ring-down spectroscopy (CRDS, Los Gatos Research) for the measurements of δ15Nα, δ15Nβ, δ18O of N2O.  Right: Isotopic N2O Analyzer (Los Gatos Research) of the Chemical Oceanography Unit The facilities, renewed in 2012, are composed  of an elemental analyser (Vario MICRO cube,  Elementar) and a gas chromatography (Agilent)  coupled to an isotope ratio mass spectrometer (Isoprime 100, Isoprime).  The GC is also equipped with a quadrupole mass spectrometer.  The Chemical Oceanography Unit Contact: Dr. A. B. Borges (alberto.borges@ulg.ac.be) Publications: http://www.co2.ulg.ac.be  Mixing modelling The use of mixing models allow to calculate the contribution  of different potential  food sources to the  diet of a species  Delineation of marine trophic web  Description of the trophic niche The fact that the isotopic composition of an animal is strongly determined by the isotopic composition of its food, allow the use of natural isotope abundance (C, N, S) as food web tracers. -35 -30 -25 -20 -15 -1001234513C: G.aequicauda: -16.4  08G.fucicola: -19.7  0.515N: G.aequicauda: 3.0  0.6G.fucicola: 2.2  0.413C (‰)‰Example of δ13C and δ15N of crustacean amphipods and potential food items (mean ± SD) sampled in Posidonia litter in the Gulf of Calvi, France (Lepoint et al. 2006) Modelling with SIAR. Dietary contributions (%) of the food source “Crustaceans” to the diet of 3 isopods (Sturaro et al., 2010). Black and grey boxes are the 50, 75 and 95% credibility intervals The measurements of δ15Nα, δ15Nβ, δ18O of N2O will allow us to characterize the origin of  N2O in a variety of aquatic environments including groundwaters in Wallonia, rivers and lakes in Wallonia and Africa, coastal environments (Scheldt estuary, Lake Greve-lingen, North Sea), Mediterranean seagrass bed and Antarctic and Arctic sea-ice.   This instrumentation will allow us to examine the isotopic composition in 15N and 18O of natural N2O, or of N2O produced in incubations with addition of labeled 15N-NH4+ and/or 15N-NO3-. Nitrous oxide (N2O) is a potent greenhouse  gas and is the dominant ozone-depleting substance  emitted in the 21st Century. Rivers, estuaries and Coastal  zones contribute to about 25% of total anthropogenic N2O  sources, while the oceans contribute to 35% of total natural N2O sources.  Example of N2O data acquired by the unit in the frame of an on-going project in Lake Kivu  Aim of the research Stable isotope compositions (C, N , S) allow us to investigate potential relations between animal diet and their pollutant contaminations.  Chlordecone concentrations versus trophic level in invertebrates colonizing a river of Guadeloupe with different water regimes (Coat et al. 2011) Case study: Stable isotope compositions of feathers allow to discriminate the 3 habitats of the White-tailed eagle in relation with brominated flame retardant contamination  (Eulaers et al. 2014)  Study areas  Applications This approach has been applied mainly to marine vertebrates (fish, turtles, mammals, birds) and freshwater ecosystems. Targeted pollutants are trace elements (e.g. Hg) and organo-chlorated or brominated pollutants.   Stable isotope compositions may also help to explain spatial variability of pollutant contaminations. The trophic niche width can be evaluated using methods estimating the degree of individual specialisation within a population.  Posidonia litter Drift photophilous algae  plus epiphytes  Drift sciaphilous algae % I. baltica I. hectica C. prismatica 

Applications of stable isotopes in environmental studies at the University of Liege

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Applications of stable isotopes in environmental studies at the University of Liege

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