LAUSR

ABSTRACT Rumolo, P.; Carannante, M.; Gherardi, S.; Tamburrino, S.; Vallefuoco, M.; Migliaccio, R.; D'Argenzio, C., and Barra, M., 2017. Measuring stable carbon and nitrogen isotopes in Mytilus galloprovincialis to elucidate the sources of organic matter in three different nearshore marine environments. Stable carbon and nitrogen isotopes (δ13C and δ15N) in mussels (Mytilus galloprovincialis) were used to elucidate the sources of sedimentary organic matter in nearshore marine environments at three different locations: (1) Naples harbour, (2) Formia harbour, and (3) Gulf of Gaeta (Tyrrhenian Sea). The sites showed different environmental characteristics, with the latter one considered as the control site, because it hosts “mussel farms” cultivated for human food. Significant differences in both δ13C and δ15N were found at Naples harbour compared to the other two sites. In particular, the lowest δ15N (>4‰) and the highest δ13C (≥1.6‰) values were found in mussels collected in Naples harbour, while similar δ13C and δ15N values were detected in Formia harbour and in the Gulf of Gaeta. As shown by a Stable Isotope Analysis in R (SIAR)-mixing model, 15N-depleted and 13C-enriched mussels highlight the influence of anthropogenic inputs on this area, particularly of organic fertilizers.