Benthic trophic network in the Bay of Banyuls-sur-Mer (northwest Mediterranean, France): An assessment based on stable carbon and nitrogen isotopes analysis

Abstract : The benthic trophic network in the Bay of Banyuls-sur-Mer was studied through the carbon and nitrogen isotopic characterization of a large set of soft-bottom macrobenthic invertebrates, fishes and potential food sources. Continental inputs as well as seagrass meadows did not contribute significantly to this benthic trophic network as indicated by: (1) the difference between their delta C-13 signatures (respectively -28.4 parts per thousand and -9.5 parts per thousand) and those of sampled animals (between -21.0 parts per thousand and -14.6 parts per thousand) and (2) their low inputs to the bay. Benthic primary consumers fed mostly on surface sediment organic matter (SSOM), which tightly interacts with suspended particulate organic matter (SPOM) and sedimenting organic matter (STOM) due to sediment resuspension. Our results also suggest the occurrence of a transfer between marine SPOM and some invertebrates (e.g. Veretillum cynomorium) and fishes (e.g. Boops boops and Spicara melanurus) through zooplankton. Moreover, the different types of primary consumers (i.e., suspension-feeders, interface-feeders, surface deposit-feeders and subsurface deposit-feeders) preferentially used distinct fractions of the heterogeneous SPOM-STOM-SSOM pool. These differences were mostly related with feeding depth and resulted in distinct isotopic signatures. Differences in the stable isotopic ratios of suspension and interface-feeders could also partly reflect the use of microphytobenthos by the later. Assuming a N-15-enrichment factor of 3.4 parts per thousand between the lower and upper ranges of two successive trophic levels, we estimated that the benthic food web of the Bay of Banyuls-sur-Mer was composed of 4 trophic levels. The comparison with our delta(13)C values suggests that the whole trophic food chain is affected by continental inputs at the immediate vicinity of the Rhone River mouth even though these effects are maximal for deposit-feeding and carnivorous polychaetes.
Type de document :
Article dans une revue
Estuarine, Coastal and Shelf Science, Elsevier, 2007, 72 (1-2), pp.1-15. 〈10.1016/j.ecss.2006.10.001〉
Liste complète des métadonnées

http://hal.univ-brest.fr/hal-00485305
Contributeur : Ivo Grigorov <>
Soumis le : jeudi 20 mai 2010 - 14:48:08
Dernière modification le : mercredi 21 mars 2018 - 18:57:20

Identifiants

Collections

Citation

Antoine Carlier, Pascal Riera, J.-M. Amouroux, Jean-Yves Bodiou, Antoine Grémare. Benthic trophic network in the Bay of Banyuls-sur-Mer (northwest Mediterranean, France): An assessment based on stable carbon and nitrogen isotopes analysis. Estuarine, Coastal and Shelf Science, Elsevier, 2007, 72 (1-2), pp.1-15. 〈10.1016/j.ecss.2006.10.001〉. 〈hal-00485305〉

Partager

Métriques

Consultations de la notice

477