|Trophic web and coastal ecosystem under anthropic pressure||
Context and IssuesThe main objective of Retrocan is to understand terrestrial vs offshore influences on marine coastal ecosystem functioning. It is focused on the northern part of the Bay of Biscay and based on a two-scale transect approach using trophic markers (C and N isotopes and fatty acids) measured at various levels of the benthic food web. The first scale concerns the bays (3-40 m deep) sheltered by islands and shoals. The second scale concerns gradients from inshore to the continental margin (3-170 m deep).
- Isotopic spatio-temporal trends from primary producers to secondary consumers give evidence of a clear contrast in the functioning of the Bay of Brest compared to the Bay of Vilaine, where freshwater inputs are much larger.
- Isotopic N of benthic consumers (invertebrates and fish) shows a general decreasing trend across the continental shelf. Questions arise about N isotopic fractionation and food sources at greater depths, where, according to fatty acid analysis, the latter are more characterised by detrital material.
Publications issued from the project
MORTILLARO, J.-M. SCHAAL, G. GRALL, J. NEROT, C. BRIND'AMOUR, A. MARCHAIS, V. PERDRIAU, M. LE BRIS, H. (2014) .Comparative study of isotopic trends in two coastal ecosystems of North Biscay: a multitrophic spatial gradient approach
NEROT, C. (2011) .Invertebres benthiques et biomarqueurs: temoins du fonctionnement trophique des ecosystemes cotiers
Funding and Support
IFREMER (Oceanographic Vessel Gwen Drez)
CNRS-Insu and Ifremer (support Ecosphère Continentale et Côtière “Retrocan”)
Council of Bretagne (grant Stratégie d’Attractivité Durable “Recomab”)
Université Européenne de Bretagne (grant Equipes Projets Transversaux “Moresca”)