Publications des scientifiques de l'IRD

Sardenne Fany, Hollanda S., Lawrence S., Albert-Arrisol R., Degroote M., Bodin Nathalie. (2017). Trophic structures in tropical marine ecosystems: a comparative investigation using three different ecological tracers. Ecological Indicators, 81, p. 315-324. ISSN 1470-160X.

Titre du document
Trophic structures in tropical marine ecosystems: a comparative investigation using three different ecological tracers
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000417229100032
Auteurs
Sardenne Fany, Hollanda S., Lawrence S., Albert-Arrisol R., Degroote M., Bodin Nathalie
Source
Ecological Indicators, 2017, 81, p. 315-324 ISSN 1470-160X
We looked at how three ecological tracers may influence the characterization and interpretation of trophic structures in a tropical marine system, with a view to informing tracer(s) selection in future trophic ecology studies. We compared the trophic structures described by stable isotope compositions (carbon and nitrogen), the total mercury concentration (THg) and levels of essential fatty acids (EFA) at both the individual and species level. Analyses were undertaken on muscle tissue samples from fish and crustacean species caught in the waters surrounding the Seychelles. The carbon isotope composition (delta C-13) correlated to the proportion of arachidonic acid (ARA), whereas the nitrogen isotope composition (delta N-15) correlated to the proportion of docosahexaenoic acid (DHA) and THg. At the individual level, trophic position obtained with these three last tracers are similar. In ' contrast, the eicosapentaenoic acid (EPA) was not clearly correlated to any of the tracers. At the species level, the use of EFA (ARA and DHA), as compared to stable isotopes, resulted in slight structural modifications, mainly in the middle trophic levels. For example, the EFA overestimated the trophic positions of Thunnus alalunga and Etelis coruscans but underestimated the trophic positions of other snappers and groupers. While ARA mainly originates from coastal/benthic areas, DHA is conserved throughout the food web and may be used as a proxy indicator of trophic position. However, metabolic disparities can affect ecological tracers and in turn, distort the trophic structures derived from their results. This is especially true for species with close trophic ecologies. Despite these caveats, we think that analysing at the individual level the wealth of ARA, DHA and THg data that has already been obtained through earlier nutrition or food security studies would enhance our understanding of trophic structures.
Plan de classement
Ecologie, systèmes aquatiques [036] ; Pollution [038] ; Ressources halieutiques [040]
Description Géographique
OCEAN INDIEN ; SEYCHELLES
Localisation
Fonds IRD [F B010071432]
Identifiant IRD
fdi:010071432
Contact