Microeukaryotic Diversity Of The Surface Layer Sediments From East China Sea

At first, We discussed the choice of pimers were amplified in microeukaryotic sequences. Three pairs of universal primer(ITS1/ITS4, EF3/EF4 and NS1/NS4) were applied to the determination of amplification specificity and diversity difference in microeukaryotic isolated from surface sediment of the East China Sea shelf, station DH-13. The result showed that the diversity of species amplified by primers NS1/NS4, EF3/EF4, ITS1/ITS4 decreased in turn. Compared with NCBI Gen Bank Data, we found that the dominant species mainly belong to the Protista, which includes Cercozoa(accounting for 36.4 % of the total OTU), Dinophyceae(14.2%), Stramenopiles(7.4%) and Ciliophora(6.3%); meanwhile, part of the species belongs to Fungi, such as Ascomycota(7.4%) and Chytridiomycota(6.3%). In the class of Protista, primer NS1/NS4 showed the highest diversity, and it fitted for the amplification about genus Cercozoa, Dinophyceae and Stramenopiles, moreover, exclusive species was also amplified, such as Euglenozoa, Cryptophyta and Apicomplexa. Primers ITS1/ITS4 fitted for the species within genus Dinophyceae and Dinophyceae, while EF3/EF4 fitted for Cercozoa. About fungus, ITS1/ITS4 fits for the species within genus Ascomycota; EF3/EF4 fitted for the species within genus Ascomycota and Chytridiomycota, while NS1/NS4 merely fitted for the genus Chytridiomycota. This result suggested that the difference of three pairs of the primer on the amplification of marine sedimentary microeukaryotes, we should choose the suitable primers or combine with the use of multiple primers according to the purpose of the study.Then we used the primer NS1/NS4 to investigate the diversity of microeukaryotes in surface layer of sediments from the East China Sea(ECS), and redundancy analysis(RDA) to reveal the relationship between sediment microbial community diversity and environmental parameters(TC, TN, TP, TOC, TIC). Most clone sequences were affiliated to protists(72.6%), dominated by Alveolata(57.2%) and Rhizaria(12.0%). The other clone sequences belonged to Metazoa(17.6%), Stramenopiles(3.4%), fungi(2.6%), Apusozoa(2.1%) and undefined(1.7%). The taxonomic identification and phylogenetic analysis showed site DH-13 had the highest diversity, a number of the clones were related to anoxic environment clones or polar region clones. RDA data displayed some environmental parameters greatly affected the sediment microbial community diversity. Our results indicated the high diverse protists in surface sediments from ECS, and pointed out several phylotypes would possess the potential to be indicators of some environmental parameters.