Abstract：
Harmful algal bloom (HAB) is a rapidly expanding marine ecological hazard. Although numerous studies have been carried out about the ecological impact and the ecological mechanism of HAB outbreaks, few studies have comprehensively addressed the shifts of species composition, metabolic activity level, driving factors and community assembly mechanisms of microeukaryotic plankton in the course of the bloom event. To fill the gap of research, we conducted 18S ribosomal DNA and RNA sequencing during the initiation, development, sustenance and decline stages of a Scrippsiella acuminata (S. acuminata) bloom at the coastal sea of Fujian Province, China. We found that the bloom event caused a decrease in microeukaryotic plankton species diversity and increase in community homogeneity. Our results revealed that the RNA- and DNA-inferred communities were similar, but α-diversity was more dynamic in RNA- than in DNA-inferred communities. The main taxa with high projected metabolic activity (with RNA:DNA ratio as the proxy) during the bloom included dinoflagellates, Cercozoa, Chlorophyta, Protalveolata, and diatoms. The role of deterministic processes in microeukaryotic plankton community assembly increased during the bloom, but stochastic processes were always the dominant assembly mechanism throughout the bloom process. Our findings improve the understanding of temporal patterns, driving factors and assembly mechanisms underlying the microeukarytic plankton community in a dinoflagellate bloom.
摘要：
有害藻华（HAB）是一种迅速发展的海洋生态危害。尽管已经对HAB爆发的生态影响和生态机制进行了大量研究，很少有研究全面解决物种组成的变化，代谢活动水平，微真核浮游生物在开花事件过程中的驱动因素和群落组装机制。为了填补研究空白，我们在启动过程中进行了18S核糖体DNA和RNA测序，发展,尖锐湿疣的维持和衰退阶段(S.acuminata）在福建省沿海海域开花，中国。我们发现，开花事件导致了微真核浮游生物物种多样性的减少和群落同质性的增加。我们的结果显示，RNA和DNA推断的群落是相似的，但是RNA-中的α-多样性比DNA推断的群落更动态。在开花期间具有高预期代谢活性（以RNA：DNA比率为代表）的主要类群包括鞭毛藻，Cercozoa,绿藻门,Protalveolata,和硅藻。在开花期间，确定性过程在真核浮游生物群落组装中的作用增加，但是在整个开花过程中，随机过程始终是主要的组装机制。我们的发现提高了对时间模式的理解，鞭毛藻水华中微真核浮游生物群落的驱动因素和组装机制。
