Metabarcoding and metagenomic data across aquatic environmental gradients along the coasts of France and Chile

Coastal marine environments, such as lagoons, fjords or estuaries, experience pronounced environmental variability, with fluctuations in salinity, temperature and nutrient levels shaping microbial community structure and function. These gradients result in diverse habitats, which may harbour taxonomic and genetic novelty with biogeochemical and biotechnological relevance. To explore microbial diversity and functional potential across these dynamic ecosystems, we sampled 26 sites along the coasts of France and Chile, including lagoons, estuaries, fjords, harbours, as well as coastal and offshore marine sites. Surface waters were collected from all sites, with deeper layers included at three sites. Monthly sampling at six sites in France enabled the assessment of seasonal dynamics. In total, 116 samples were processed for both metabarcoding and metagenomic sequencing yielding over 53,000 amplicon sequence variants (ASVs) and 1,372 metagenome-assembled genomes (MAGs). This dataset further includes a comprehensive gene catalogue and environmental variables such as salinity, temperature, nutrient concentrations, productivity, as well as oxygen consumption metrics collected across the different ecosystems.