Closely related bacterial community during and after the marine Akashiwo sanguinea(Dinophyta) blooms for in-door microcosm evidences

Abstract

We investigated dynamics of the bacterial composition and metabolic function in Akashiwo sanguinea bloom using the 100-L indoor microcosm and metagenomic next-generation sequencing. We found that the bacterial community was classified into three groups at 54% similarity. Group I was associated with “during A. sanguinea bloom stage” and mainly consisted of Alphaproteobacteria(48.51%), Flavobacteriia(47.32%), and Gammaproteobacteria(3.43%). Meanwhile, groups II and III were associated with “late bloom/decline stage to post-bloom stage”. Flavobacteriia and Gammaproteobacteria decreased in Group II but increased again to 41.05% and 5.85% in Group III, respectively. With the termination of A. sanguinea bloom, the concentrations of inorganic nutrients, particularly PO43-, NH4+ and dissolved organic carbon, increased rapidly and then decreased. From the network analysis, we found that A. sanguinea node is associated with certain bacteria, and after the bloom, the specific increases in NH4+ and PO43- nodes are associated with other bacterial taxa. The changes in the functional groups of bacteria community from chemoheterotrophy to nitrogen association metabolisms were consistent with environmental impacts during and after A. sanguinea bloom. Consequently, certain bacteria taxa and the environments dynamically changed during and after HABs bloom and a rapid turnover in the bacterial community and their function can respond to ecological interactions.