Pinna nobilis is a large bivalve endemic to the Mediterranean Sea that lives in shallow coastal areas. Due to its size and relatively fast shell growth rates, it is an interesting taxon for high-resolution study of nitrogen isotopes of carbonate bound organic matter (δ 15 N CBOM ). In this study we tested if P. nobilis shells can be used as an indicator of the nitrogen isotope baseline of the system, if it can provide high-res...