Integrating source tracking tools for marine shellfish tracing: Metataxonomic and isotopic analyses

Abstract

Shellfish farming is a significant activity in the Northern Adriatic Sea, particularly in Italy, where it plays a crucial role in the European industry of live bivalve mollusks. This study aimed to exploit different analyses, including metataxonomy and isotopic profiling, to address these issues. Isotopic analysis showed differences between habitats, with lower δ15N in sea samples, likely indicating lesser anthropogenic impact compared to lagoon environments. Additionally, seasonal variations in δ15N, δ13C and C/N highlighted differences in primary productivity and organic matter sources across seasons. Metataxonomic analysis revealed significant variability in microbial taxa across harvesting habitats and seasons. While no marked differences were observed in alpha and beta diversity based on habitat, distinct seasonal clustering indicated the influence of environmental factors on microbial community structure. Gammaproteobacteria were prevalent across habitats and seasons, with notable fluctuations in other taxa, such as Alphaproteobacteria, Epsilonproteobacteria, Flavobacteria, and Bacteroidia, particularly in lagoon habitats during winter. Overall, this study highlights the potential of microbial and isotopic characterization for tracing the origin of shellfish products. Metataxonomic analysis identified microbial signatures indicative of habitat and season, with implications for ecological dynamics and consumer safety. Isotopic analysis provided information on habitat characteristics and harvesting seasons, enhancing product traceability.