High-throughput sequencing and comparative analysis of eukaryotic phytoplankton community in Liaodong Bay, China

Abstract The phytoplankton community of Liaodong Bay was characterized in 2014. Considering that the continuous change in taxonomic composition and abundance was a significant characteristic of phytoplankton communities in the sea, phytoplankton community was continuously detected in 2015. Results showed that the average phytoplankton operational taxonomic units (OTUs) of each sample was 200-561. The same as in 2014, Dinophyceae abundance was still the highest in June and August of 2015 according to OTUs. Nineteen algal species could cause toxicity to disrupt food webs, and thirty-one species had been reported as causing algal blooms, four more than in 2014. Among algae documented as bloom-forming species, Akashiwo sanguinea, Amylax triacantha, Ostreococcus tauri, and Kryptoperidinium foliaceum were observed in August, while Pyrophacus steinii, Phaeocystis globosa, and Nannochloropsis granulata appeared only in June. Other algae with documented blooms were detected both in June and August of 2015. In the near-shore (NS) group, inner-shore (IS) group, and off-shore (OS) group, the number of algal species in August was higher than that in June in 2015. In NS and IS group, the dominant species were mainly Cryptophyceae and Haptophyta, respectively, while they belonged to Haptophyta and Bacillariophytina in OS.