Annual succession of dinoflagellate community on temperate coast zone (the southern coast of South Korea)

Abstract

To identify the succession of dinoflagellates on the southern coast of South Korea, the total phytoplankton transition was analyzed through 18s rDNA Metabarcoding analysis at 3 day intensive (311 time series monitoring) from November 2018 to June 2020. In a total of 16,224 ASVs (amplicon sequencing variables), 43% of dinoflagellate taxa (total 217 ASVs) appeared, and 66% of dinoflagellates appeared in total relative abundance. The dinoflagellates community was classified into seasonal groups using Bray-Curtis dissimilarity. In common dinoflagellates taxa (with a mean relative abundance >1% in all samples) appearance was selected as 8 dominant taxa. The predominant taxa of Heterocapsa rotundata (All times), Akashiwo sanguinea (Oct,2019, Mar-May,2020), Gymnodinium sp.(May-Jun,2019), Euduboscquella sp. (Nov-Dec,2018, Dec,2019, Jan-Feb and May-Jun,2020), Amoebophyra sp. (Jun-Jul,2019, Jan,2020), Karlodinium veneficum (Jan, Mar and Aug-Sep,2019), Katodinium glaucum (Apr, Nov,2019), Dissodinium pseudolunula (Feb and Aug,2019, Feb-Mar,2020). Overall, Heterocapsa rotundata was predominant on the coast of Geoje from 2018 to 2020. Also, harmful species such as Akashiwo sanaguinea and Gymnodinium sp. and parasitic and dinoflagellate Amoebophyra sp. increased, whereas Heterocapsa rotundata rapidly decreased. This reduction suggests that growth inhibition is due to harmful substances in the dinoflagellates or intra-species community transitions due to host-parasite relationships. In further studies, we will investigate why these predominant species are affected by environmental factors through ecological analysis between the environment and major indicator species.