Metabarcoding analysis identifies high diversity of harmful algal bloom species in the coastal waters of the Beibu Gulf

Abstract

Harmful algal blooms (HABs) have occurred more frequently in recent years. In this study, to investigate their potential impact in the Beibu Gulf, short‐read and long‐read metabarcoding analyses were combined for annual marine phytoplankton community and HAB species identification. Short‐read metabarcoding showed a high level of phytoplankton biodiversity in this area, with Dinophyceae dominating, especially Gymnodiniales. Multiple small phytoplankton, including Prymnesiophyceae and Prasinophyceae, were also identified, which complements the previous lack of identifying small phytoplankton and those unstable after fixation. Of the top 20 phytoplankton genera identified, 15 were HAB‐forming genera, which accounted for 47.3%–71.5% of the relative abundance of phytoplankton. Based on long‐read metabarcoding, a total of 147 OTUs (PID > 97%) belonging to phytoplankton were identified at the species level, including 118 species. Among them, 37 species belonged to HAB‐forming species, and 98 species were reported for the first time in the Beibu Gulf. Contrasting the two metabarcoding approaches at the class level, they both showed a predominance of Dinophyceae, and both included high abundances of Bacillariophyceae, Prasinophyceae, and Prymnesiophyceae, but the relative contents of the classes varied. Notably, the results of the two metabarcoding approaches were quite different below the genus level. The high abundance and diversity of HAB species were probably due to their special life history and multiple nutritional modes. Annual HAB species variation revealed in this study provided a basis for evaluating their potential impact on aquaculture and even nuclear power plant safety in the Beibu Gulf.

Metabarcoding reveals a high diversity and complex eukaryotic microalgal community in coastal waters of the northern Beibu Gulf, China

“…* Historical algal bloom species ( Xu et al, 2019 ). † Taxa shared with those reported in He et al, 2023 . MB, Metabarcoding; LM, Light microscopy; CFP, ciguatera fish poisoning; DA, Domoic acid; DSP, Diarrhetic shellfish poisoning; PSP, Paralytic shellfish poisoning; YTX, Yessotoxin.…”

“…A total of 48 algal bloom and/or HAB taxa were identified in this study, however, only three species of them ( Skeletonema costatum , Noctiluca scintillans , and Phaeocystis globosa ) formed blooms previously in the Beibu Gulf ( Xu et al, 2019 ). He et al (2023) detected 37 HAB species by metabarcoding in one station during the eight surveys between 2016 and 2017, but only nine HABs were the same as in our study ( Table 3 ). These results suggest rich and diverse HAB species in the Beibu Gulf, which may fluctuate greatly with sampling time.…”

Morphological and Molecular Characterization of the Unarmored Dinoflagellate Gymnodinium trapeziforme (Dinophyceae) from Jiaozhou Bay, China

“…Jeong & Ø. Moestrup [40] in Chinese coastal waters has also been confirmed via high-throughput metabarcoding sequencing, however, the other two recorded species, G. bei H.J. Spero [39] and G. heterostriatum Kofoid & Swezy [39], have been reclassified as Pelagodinium bei (H.J.Spero) Siano, Montresor, Probert & Vargas, and Gyrodinium heterostriatum (Kofoid & Swezy) F. Gómez, Artigas & Gast. Most recently, we established a clonal culture of Gymnodinium species from the coastal water of Jiaozhou Bay, China in 2020, which provided further characterization of its morphology using light, scanning electron microscopy, and phylogenetic analysis based on partial LSU rDNA sequence.…”

“…In addition, the presence of G. aureolum (Hulburt) Gert Hansen [38], Gymnodinium cf. nolleri M. Ellegaard & Moestrup [39], and G. smaydae N.S. Kang, H.J.…”