Deciphering biological community changes along European coastlines during the Anthropocene through paleogenomic

Since the beginning of the intensive human activities on Earth (marking the Anthropocene) coastal biodiversity has undergone profound structural and compositional shifts. Paleogenomic approaches now allow to trace and analyze these long-term changes, even in heavily disturbed ecosystems.To assess the effects of major anthropogenic pressures in Europe such as eutrophication, industrialization, aquaculture, and urbanization, shifts in bacterial and eukaryotic biodiversity were assessed using sedimentary ancient sedaDNA-based metabarcoding and metagenomics. As part of the TREC expedition, sediment cores (ca. 1 m) were collected from 15 coastal sites across 9 European countries (France, Spain, Italy, Greece, Sweden, Germany, Poland, Estonia, and Finland).Radioisotope dating confirmed that all sediment cores span time periods linked to pollution events and/or ecosystem shifts at each site. Metabarcoding (targeting V4, V9 18S rDNA and V4-V5 16S rDNA regions) and metagenomic analyses were conducted on samples corresponding to these intervals of human impact, as corroborated by contaminant profiles.Cross-site and cross-country comparisons will test hypotheses regarding biodiversity loss, shared community trajectories in response to specific anthropogenic pressures, and regional temporal dynamics of invasive species.