Four research cruises (in October, November, December, and February) collected seawater for molecular analyses following major storms that affected the Gulf Coast of Florida. Seawater was sequentially filtered through 3.0 and 0.2 um pore-size filters to characterize size-fractionated bacterial, protistan, and fungal communities. Filters were stored in Zymo DNA/RNA shield, and DNA was extracted with the Zymo Microbiomics kit. The ITS, 16S rRNA, and 18S rRNA genes were amplified in separate reactions and sequenced with Illumina NextSeq 300 x 300 bp flow-cells.