Particle-attached and free-living microbial community composition, metagenomes, and metagenome-assembled genomes of surface seawater in Daya Bay during wet and dry seasons in 2023

Surface seawater samples were collected at a fixed station in Daya Bay, a subtropical coastal bay in the northern South China Sea, across seven time points in 2023, covering both wet (3 April, 17 August, 18 September) and dry (16 February, 16 March, 27 March, and 30 November) seasons, with three biological replicates per sampling event. Seawater was sequentially filtered through 3.0 um and 0.2 um pore-size filters to separate particle-attached (3-200 um, labeled as 3um in sample names) and free-living (0.2-3 um, labeled as 0.2um in sample names) microbial communities. Multi-omics sequencing was conducted to characterize microbial community composition, functional potential, and population genomes. 1. Metagenome data: Shotgun metagenomic sequencing was performed to investigate the functional potential and genomic diversity of microbial communities across both size fractions (0.2um and 3um) and seasonal conditions. 2. 16S/18S rRNA data: Prokaryotic community composition was assessed by 16S rRNA gene amplicon sequencing from both particle-attached and free-living fractions, while eukaryotic community structure was characterized by 18S rRNA gene amplicon sequencing from the particle-attached fraction. 3. Metagenome-assembled genomes (MAGs): Metagenome-assembled genomes were reconstructed from the metagenomic datasets. Genome binning was conducted using MetaBAT2, and bin quality was assessed with CheckM. High-quality MAGs were retained based on >90% completeness and <5% contamination.