Particle-attached bacterioplankton and eukaryote composition of surface seawater during the spring bloom at Helgoland in the year 2018

16S rRNA amplicon and 18S rRNA sequencing of surface seawater samples collected at Helgoland during the spring bloom in the year 2018. Samples were successively filtered through 10, 3, and 0.2 µm pore-sized polycarbonate filters to separate the bulk of free-living (0.2 µm) from the bulk of particle-attached bacteria (3 and 10 µm). This sample refers to the 3-10 µm and >10 µm fractions. 16S rRNA sequencing was done on the Illumina HiSeq2500 sequencing platform in rapid mode with 2x 250 bp paired-end reads using primers targeting the V4 region. 18S rRNA was done on the Illumina MiSeq sequencing platform.