MEPS 187:301-307 (1999)  -  doi:10.3354/meps187301

ABSTRACT: δ¹³C and δ¹⁵N were measured in benthic invertebrates and food sources collected in the salt marsh of the Aiguillon Bay, France. The results showed that, although Spartina anglica was dominant, this marine phanerogame did not contribute significantly to the carbon and nitrogen requirements of the invertebrates considered in this study. In fact, Macoma balthica, Scrobicularia plana and Mytilus edulis preferentially fed on a mixture of benthic diatoms and marine phytoplankton, but in different proportions, as was estimated through isotope mixing models. However, this isotopic data set revealed complex trophic relationships for the nematode community and for the crab Carcinus maenas which did not allow accurate isotopic determination of food sources.

KEY WORDS: Carbon and nitrogen isotope ratios · Muddy salt marsh · Spartina anglica · Benthic diatoms · Benthic invertebrates