Food source of intertidal nematodes in the Bay of Marennes-Oleron (France), as determined by dual stable isotope analysis

Nematodes living on an intertidal mudflat of the Marennes-Oleron Bay (France) were assayed for delta(13)C and delta(15)N ratios together with their potential food resources between July 1992 and May 1993. Results suggest that nematodes do not exploit all the components of the sedimented organic matter (SOM) pool at the same rate. Furthermore, based on coefficients of average trophic enrichment found in the literature for both C and N, the enrichment of nematodes in C-13 and their depletion in N-15 relative to SOM suggest that microphytobenthos constitutes their main food source in this particular environment.