Diversity and geographical distribution of resting stages of eukaryotic algae in the surface sediments from the southern Chinese coastline based on metabarcoding partial 18S rDNA sequences

Abstract

Surface sediment samples were collected from sixteen sites of the southern Chinese coastline in this study. Diversity of eukaryotic microalgae was examined using high‐throughput sequencing of 18S rDNA to understand the community structure and geological distribution of microalgal resting stages. A total of 218 operational taxonomic units (OTUs) were detected for eukaryotic algae, and only 75 OTUs (34.40%) were detected into species level. The algal communities were composed of sixty‐four genera belonged to twelve classes of four phyla. Dinoflagellates were the most abundant and diversified group, which accounted for the average of 56.26% and 53.70% DNA reads and OTUs, respectively. Dinoflagellates were dominated by Protoperidinium, Euduboscquella, Amylax, and Paragymnodinium. Chaetoceros, Thalassiosira, and Skeletonema were abundant in diatoms, while Pedospumella and Paraphysomonas in Chrysophyceae were the most abundant genera due to their massive occurrence in some particular sites. The high abundance of Protoperidinium sequences suggested the high nutrient levels in the southern Chinese coastline. Nineteen of the detected OTUs were assigned to harmful and/or bloom‐forming microalgae. The wide occurrence of the toxic dinoflagellate Azadinium poporum and high abundance of Alexandrium pacificum in some particular sites suggested the potential risk of human poisoning.

Metabarcoding of harmful algal bloom species in sediments from four coastal areas of the southeast China

“…Dinoflagellates also had the highest OTU richness. The algal community structure in this study is comparable to those reported in sediments from the other coastal sea areas based on metabarcoding analysis, in which dinoflagellate DNA reads and OTU richness were predominated ( Dzhembekova et al, 2018 ; Liu et al, 2020a ). Dinoflagellates have much higher DNA copies (up to thousands) than the other protists (dozens to hundreds) ( Lin, 2011 ), which may lead to their over-representation in metabarcoding studies.…”

“…A total of 3,899 eukaryotic OTUs including 454 algal OTUs were detected in the 30 surface sediment samples from the four sea areas along the southeast Chinese coasts in this study. The OTU richness in this study was much higher compared with those observed in surface sediments from other sea areas, for example 180 OTUs of microalgal species were identified from 13 stations across the Black Sea ( Dzhembekova et al, 2018 ), and 218 algal OTUs in 16 stations along the southern Chinese coast ( Liu et al, 2020a ). The results suggest that investigations in diverse sea areas may enhance the OTU richness.…”

Distribution of Dinoflagellate Cysts in Surface Sediments From the Qingdao Coast, the Yellow Sea, China: The Potential Risk of Harmful Algal Blooms

“…The potential AZP producer, Azadinium poporum, occurred in all stations except for those in the inner Jiaozhou Bay, and ranked the sixth most abundant cyst type (Figure 6). A. poporum was reported to distribute widely in surface sediments from the Chinese coasts (Gu et al, 2013;Liu et al, 2020;Tang et al, 2021), and 13 out of 16 strains of A. poporum from different geographic locations along the Chinese coastline contained AZPs (Krock et al, 2014). However, species in Azadinium has been seldom reported in the phytoplankton survey, which might be ignored due to their small Biecheleria halophila was the most abundant cyst type in sediments from the Qingdao coast in our study.…”

“…Biecheleria has become more frequently detected in the phytoplankton communities as the development of molecular biological techniques (Sundstrom et al, 2010). Taxa in Biecheleria generally form resting cysts (Moestrup et al, 2009), which made them common dominant eukaryotes in sediments based on metabarcoding analysis (Dzhembekova et al, 2018;Liu et al, 2020;Rhodes et al, 2020). B. halophila was reported to form a co-occurring bloom with Scrippsiella hangoei in the Baltic Sea (Kremp et al, 2005).…”

Annual dynamics of eukaryotic and bacterial communities revealed by 18S and 16S rRNA metabarcoding in the coastal ecosystem of Sagami Bay, Japan

“…Many species of dinoflagellates form resting cysts and have different life cycles that consist of a cyst and motile stage. The genus Euduboscquella parasitises Tintinnids and produces cysts (Dolan et al 2013;Shang et al 2019;Liu et al 2020). The temporal dominance of Amoebophrya sp.…”