Stable isotopes and fatty acids used as biomarkers to distinguish among Antarctic amphipods trophic guilds

Conference (2003)

Peracarid crustaceans and amphipods in particular are an important group in the Southern Ocean and one of the most diverse in the macrozoobenthos (Jazdzewski et al., 1991). As a part of a ... [more ▼]

Peracarid crustaceans and amphipods in particular are an important group in the Southern Ocean and one of the most diverse in the macrozoobenthos (Jazdzewski et al., 1991). As a part of a multidisciplinary study of the amphipods ecological roles in Antarctic benthic systems (De Broyer et al., 2001, Nyssen et al., 2002), about 150 specimens belonging to 25 species of 10 of the most common amphipod families occurring in the Southern Ocean have been involved in this study of amphipod trophic patterns. Beside “classical” stomach content analysis or field observations, the use of naturally occurring stable isotopes of carbon (δ13C) and nitrogen (δ15N) has recently provided new insights into food web ecology (Hobson & Welch, 1992, Lepoint et al., 2000). This method is based on the direct relationship established between the isotopic signature of an organism and that of its preys (DeNiro & Epstein, 1978, 1981, Peterson & Fry, 1987). Nitrogen-15 typically shows a step-wise increase with trophic level within a food chain (Cabana & Rasmussen, 1994). Closer to the value of the diet, carbon-13 is preferentially used to assess the relative proportion of potential primary sources in a trophic web (ex.: pelagic vs benthic contribution to food intake) (Dauby et al., 1998, Hobson et al., 1995). Furthermore, for several species, the lipid signature – which has already been used successfully to help understand marine trophodynamics (Graeve et al., 2001, Nelson et al., 2001, Phleger et al. 1998) – and more particularly the fatty acid composition has been investigated as trophic biomarkers to reveal more precisely to which trophic guild they belong to. [less ▲]

Stable isotopes of captive Cetaceans (Killer Whales and Bottlenose dolphins)

in Journal of Experimental Biology (2011), 214

There is currently a great deal of interest in using stable-isotope methods to investigate diet, trophic level and migration movement in wild cetaceans. Fundamental to the interpretation of these methods ... [more ▼]

There is currently a great deal of interest in using stable-isotope methods to investigate diet, trophic level and migration movement in wild cetaceans. Fundamental to the interpretation of these methods is the need to understand how diet isotopic values are reflected in consumer tissues. In this study, we investigated patterns of isotopic discrimination between diet and blood constituents of two species of cetaceans (killer whale, Orcinus orca and 19 bottlenose dolphin, Tursiops truncutus) fed with controlled diets during 350 days. Diet discrimination factors ( ) for plasma were estimated to 13C =2.3‰ and 1520 N =1.8‰ respectively for both species and to 13C =2.7‰ and 1521 N =0.5‰ for red blood cells (RBC). Delipidation had no significant effect on carbon and nitrogen isotopic values of blood constituents, confirming that cetacean blood no serving as reservoirs of lipids. In contrast, carbon isotopic values are higher in delipidated samples of blubber, liver and muscle of orca tissues. The mean half life for plasma was 32.9 days for killer whales and 27.2 days for bottlenose dolphin and for RBC was greater than 175 days. The potential for conflict between fisheries and cetaceans has heightened the need for trophic information about this taxa within those ecosystems. These results provide the first published stable isotope turnover rates and discrimination factors for cetaceans, which are essential if conclusions are to be drawn on issues concerning trophic structures, carbon sources and diet reconstruction. [less ▲]

A stable numerical scheme for shallow flow modelling taking into account bottom curvature

in Proceedings of the 4th International Conference on Advanced Computational Methods in Engineering (2008)

Stables isotopes in the fin whale Balaenoptera physalus from the Mediterranean Sea: implications for management and conservation

Poster (2013, April)

The fin whale (Balaenoptera physalus) is the commonest large whale species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the region. This whale is ... [more ▼]

The fin whale (Balaenoptera physalus) is the commonest large whale species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the region. This whale is known to feed mainly on krill in contrast to its Atlantic counterpart, displaying a more diversified diet. δ13C and δ15N values were analysed by IR-MS (Isoprime 100) coupled to an N-C-S elemental analyser (Vario MICRO Cube, Elementar) in 113 skin biopsies from Mediterranean fin whales sampled in 2010 and 2011 during WWF campaign at sea. A lipid normalization equation was applied (adapted from Post al. 2007) because the measured C:N ratio was > 3.5. Normalized δ13C and δ15N values ranged from -20.3 to -17.3 ‰ and from 5.9 to 8.9 ‰, respectively. These values are in good agreement with those collected previously on baleen plates from Mediterranean fin whales (Bentaleb et al., 2011). A mean enrichment of 3.4 ‰ was observed between δ15N values measured in fin whale skin biopsies and Mediterranean krill (Meganyctiphanes norvegica) confirming the importance of the krill as a major food source. The narrow width of the isotopic niche of the Mediterranean fin whale (evaluated by SIBER Stable Isotope Bayesian Ellipses) compared to the Atlantic fin whale (Ryan et al. 2012) raises many concerns in the context of global changes and long-term consequences. One could expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts. [less ▲]

Stades et supporters: De la violence à la prévention des dérives passionnelles

in Revue Sport (1999), (165-166), 128

Analyse des phénomènes de violences et déviances des supporters de football et stratégies de prévention du hooliganisme par D. Bodin (Rennes), M. Comeron (Liège), J. Jacquemart (Liège), E. Jareno ... [more ▼]

Analyse des phénomènes de violences et déviances des supporters de football et stratégies de prévention du hooliganisme par D. Bodin (Rennes), M. Comeron (Liège), J. Jacquemart (Liège), E. Jareno (Barcelone), G. Kellens (Liège), F. Lovenfosse (Liège), M. Marcus (Paris), C. Moneypenny (Liverpool), Piastowski (Düsseldorf) [less ▲]

The Stadium of Olympia, from the perspective of the dialogical architecture

in proceedings (2012, May)

"Die Stadt in meinem Schoße" : Zu Gertrud Kolmars Gedicht 'Wappen von Berlin' aus dem Zyklus 'Das Preußische Wappenbuch'

in Johanning, Antje; Lieser, Dietmar (Eds.) Stadt, Land, Fluß. Urbanität und Regionalität in der literarischen Moderne (2002)

Staff development and e-tutors training

in Banks, Sheena; Goodyear, Peter; Hodgson, Vivien (Eds.) et al Networked learning 2004 : a research based conference on networked learning in higher education and lifelong learning : proceedings of the fourth international conference, Lancaster (2004)

This paper considers the rationale for the training and staff development of e-tutors. We then examine how this is implemented in practice through the presentation of case studies from three European ... [more ▼]

This paper considers the rationale for the training and staff development of e-tutors. We then examine how this is implemented in practice through the presentation of case studies from three European universities. Finally we analyse the differences and similarities of these case studies to exemplify some principles for training models and guidelines for training of e-tutors. We conclude that although it is possible to identify these principles of good practice, there is great flexibility and diversity of methods and approaches in the training and staff development of e-tutors. [less ▲]

Stages intensifs d'initiation à l'informatique

in Actes du colloque "Enseignement, formation et pratique active de l'informatique par l'enfant" (1982, December)

A Staging Model to Guide Psychological Interventions in Psychosis

in Psychiatric Services (2009), 60