ORBi: Nyssen Fabienne - Trophic position of Antarctic amphipods: enhanced analysis by a 2-dimensional biomarker assay

Reference : Trophic position of Antarctic amphipods: enhanced analysis by a 2-dimensional biomarker ...


	Document type :	Scientific journals : Article
	Discipline(s) :	Life sciences : Aquatic sciences & oceanology
	To cite this reference:	http://hdl.handle.net/2268/18472

Title :	Trophic position of Antarctic amphipods: enhanced analysis by a 2-dimensional biomarker assay
Language :	English
Alternative title :	[fr] Position trophique des amphipodes antarctiques: analyse amelioree par un biomarqueur a 2 dimensions
Author, co-author :	Nyssen, Fabienne [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Systématique et diversité animale >]
	Brey, Thomas [Alfred Wegener Institute for Polar and Marine Research > Marine ecology > > >]
	Dauby, Patrick [Université de Liège - ULG > Departement des sciences et gestion de l'environnement > Systematique et diversite animale > >]
	Graeve, Martin [Alfred Wegener Institute for Polar and Marine Research > Marine Chemistry > > >]
Publication date :	2005
Journal title :	Marine Ecology. Progress Series
Publisher :	Inter-Research Science Publishing
Volume :	300
Pages :	135-145
Peer reviewed :	Yes
Audience :	International
ISSN :	0171-8630
e-ISSN :	1616-1599
City :	Oldendorf Luhe
Country :	Germany
Keywords :	[en] 2-dimensional biomarker ; trophic relationships ; stable isotopes ; fatty acids ; Amphipoda ; Antarctic ecology
Abstract :	[en] The discrepancy between the ecological significance of amphipods in the Antarctic and our poor knowledge of their ecofunctional role calls for a more detailed investigation of their trophic status in this ecosystem. A total of 12 amphipod species from suspension feeder to scavenger have been considered in this study. Our objective was to investigate whether the combination of fatty-acid and stable-isotope signatures into a 2-dimensional trophic biomarker assay would increase accuracy in the identification of Antarctic benthic amphipod trophic position. Amphipod isotopic averages ranged from –29.3‰ (δ13C) and 4.1‰ (δ15N) for the suspension feeder Ampelisca richardsoni to –21.7‰ (δ13C) and 11.9‰ (δ15N) for the high predator Iphimediella sp. Cluster analysis of the fattyacid composition separated the amphipod species into 4 trophic groups: suspension feeders, macroherbivores, omnivores and scavengers. The suspension feeder was isolated due to an important proportion of 18:4(n-3), a fatty-acid biomarker of phytoplankton. Macro-herbivores were found to rely heavily on macroalgal carbon, containing a high percentage of arachidonic acid (20:4(n-6)). Scavenger amphipods revealed a unique fatty-acid composition dominated by 1 single fatty acid, 18:1(n- 9), probably the result of a very intensive de novo biosynthesis to cope with starvation periods. Our data emphasise the need to combine different types of information to be able to draw the right conclusions regarding trophic ecology. Indeed, in some cases, the exclusive use of 1 type of tracing method, fatty acids or stable isotopes, would have resulted in misleading/false conclusions in the trophic classification of amphipods. Therefore, a 2-dimensional biomarker assay is a useful tool to elucidate the trophic positions of benthic amphipods.
Funders :	Fonds pour la formation à la Recherche dans l'Industrie et dans l'Agriculture (Communauté française de Belgique) - FRIA ; Services Fédéraux des Affaires Scientifiques, Techniques et Culturelles - SSTC
Target :	Researchers ; Professionals ; Students
Permalink :	http://hdl.handle.net/2268/18472

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