design: design_description: "This study investigates the phytoplankton community structure and functional diversity in the Bohai and Yellow Seas using whole genome sequencing (WGS)-based metagenomics. Seawater samples were collected from multiple stations across different seasons and filtered through 0.2 m membranes to capture microbial biomass. DNA was extracted using the DNeasy PowerWater Kit (QIAGEN) and sequenced on the Illumina NovaSeq 6000 platform with paired-end 201 bp reads. The study aims to identify key phytoplankton taxa, assess metabolic potential, and examine environmental drivers of community shifts."