Spatial variation in the 15N and 13C stable isotope composition of plants, invertebrates and fishes on Mediterranean reefs:implications for the study of trophic pathways

Abstract

6I5N and 6C were determlned for plants invertebrdtes and f ~s h e s collected from 3 s ~t e s on the southern coast of the Mediterranean Island of Mallorca Spdln The sites were separated by distances of 1250 to 3750 m The mean Si5N of plants was 1 1 to 4 1 " W , , benthic Invertebrates 5 9 to 6 g':%) planktonic Invertebrates 5 5 to 5 8% and fishes 8 4 to 13 8%" 6"N became ennched with increasing trophic level The mean 6I3C of plants was -11 4 to -16 3'Xo benthlc invertebrates -14 8 to -16 8'X, planktonlc Invertebrates -19 3 to -19 8 O W b and fishes -16 1 to -19 2"y) There were s ~g n ~f i c a n t d ~f f e iences in the lsotopic c o m p o s ~t ~o n of ~ndividual specles w ~t h i n the plant invertebrate 01 flsh groupings at each slte and there were s ~g n ~f i c a n t d~fferences in the ~s o t o p ~c composit~on of the same specles at dlfferent sites Depleted ' < C was assoc~ated w ~t h b e n t h ~c food chalns and enrlched ''C w ~t h planktonlc