Diversity of mesozooplankton-associated protists in the Yangtze River Estuary and the South Yellow Sea

Mesozooplankton play key roles in marine food webs and provide diverse microhabitats for symbiotic protists. In this study, we investigated the community composition and diversity of protists associated with mesozooplankton in the Yangtze River Estuary and the South Yellow Sea using 18S rRNA gene metabarcoding. Mesozooplankton samples were collected from 22 stations during spring, summer, and autumn in 2022 using a WP2 plankton net. Amplicon libraries of 18S rRNA gene were generated using a nested PCR comprising an initial amplification with non-metazoan-specific (UNon-Met-PCR) primers 18S-EUK581-F (5-GTGCCAGCAGCCGCG-3)/18S-EUK1134-R (5-TTTAAGTTTCAGCCTTGCG-3), followed by the 2nd amplification using primers targeting the V4 region of 18S rRNA gene, E572F (5-CYGCGGTAATTCCAGCTC-3)/E1009R (5-AYGGTATCTRATCRTCTTYG-3). Amplicon libraries were sequenced on an Illumina Nextseq 300PE platform.