Eukaryotic micro-plankton plays a key role in the marine biotic community and in maintaining the stability of the marine ecosystem. In order to determine the diversity and characteristics of eukaryotic micro-plankton in the Yellow Sea, Illumina high-throughput sequencing, based on gene markers of ITS, was conducted. An analysis of the relationship between community structure and environmental factors was conducted as well. The results are summarized in the following. ① Various of species of fungi, phytoplankton, and zooplankton were obtained by high-throughput sequencing technology; for OTUs, the order is fungi > phytoplankton > zooplankton, and for reads, the order is fungi > zooplankton > phytoplankton. ② In different waters, species abundance and diversity differed from each other. The Ace index and Chao1 index demonstrated an ordering of southern Yellow Sea > northern Yellow Sea > northern East Sea > Cold Water Mass; however, for the Simpson index and Shannon-Wiener index, the tendency followed the order of northern East Sea > northern Yellow Sea > southern Yellow Sea > Cold Water Mass. Species abundance and diversity in the Cold Water Mass were lowest. ③ The reads and OTUs of fungi, phytoplankton, and zooplankton increased as temperature rose. The reads and OTUs of fungi increased as salinity increased, while there was an opposite trend for phytoplankton and zooplankton. Latitude was another significant factor. In the range of 30° to 40° north latitude, the Shannon-Wiener index for fungi and zooplankton indicated an increasing tendency with an increase in latitude, while the Shannon-Wiener index for phytoplankton showed an opposite trend. With a greater distance from the coast, the Shannon-Wiener index of fungi, phytoplankton and zooplankton was lower. This is the first study that amplifies the use ITS in the research of marine eukaryotic micro-plankton, giving an enriched understanding of eukaryotic micro-plankton. The feasibility of applying high-throughput sequencing technology in the sea is proven, and this will provide a reference for other researchers.
Keywords: Yellow Sea; diversity; high-throughput sequencing technology; internal transcribed space (ITS); micro-plankton.