BRIDGING THE GAP: ADVANCING eDNA METABARCODING FOR BIOMONITORING IN SARDINIAN COASTAL LAGOONS

COLMARE IL DIVARIO: eDNA METABARCODING PER IL MONITORAGGIO DELLE LAGUNE COSTIERE DELLA SARDEGNA

Abstract

Coastal lagoons are dynamic ecosystems that provide essential ecological and socio-economic services in the Mediterranean Sea. However, these habitats face increasing anthropogenic pressures, therefore requiring effective biomonitoring strategies. Environmental DNA (eDNA) metabarcoding is a promising approach, but its accuracy depends on how complete the genetic reference databases are. In Sardinia, lagoon biodiversity has been studied to varying extents, but there is no comprehensive synthesis on macrozoobenthic diversity and its genetic representation. We did a systematic review compiling species records and assessing their representation in global repositories for 18S rRNA and Cytochrome c oxidase I genes. A total of 536 taxa were reported in 42 lagoons, with 401 identified at the species level. Only 69% had COI barcodes, and 42% 18S rRNA sequences, with major gaps in Mollusca, Nemertea and Arthropoda (18S) and Echinodermata (COI). Expanding reference libraries is crucial for improving eDNA-based monitoring and conservation of Mediterranean coastal lagoons.