Elucidating the interactions between algae and associated microbial communities is critical for understanding the mechanisms that mediate the dynamic of harmful algal blooms (HABs) in marine environment. However, the microbial functional profiles and their biogeochemical potential in HABs process remains elusive, especially during a complete natural HAB cycle. Here, we used pyrosequencing and functional gene array (GeoChip) to investigate microbial community dynamics and metabolic potential during a natural dinoflagellate (Noctiluca scintillans) bloom. The results shown that bacterioplankton exhibited significant temporal heterogeneity over the course of the bloom stages. Microbial succession was co-driven by environmental parameters and biotic interactions. The functional analysis revealed significant variations in microbial metabolism during matter cycling. At bloom onset-stage, metabolic potential associated with iron oxidation and transport was elevated. Carbon fixation and degradation, denitrification, phosphorus acquisition, and sulfur transfer/oxidation were significantly enhanced at the plateau stage. During the decline and terminal stages, oxidative stress, lysis of compounds, and toxin degradation & protease synthesis increased. This work reveal phycosphere microorganisms can enhanced organic C decomposition capacity, altered N assimilation rate and S/P turnover efficiency, and balancing of the Fe budget during HAB process. The ecological linkage analysis has further shown that microbial composition and functional potential were significantly linked to algal blooms occurrence. It suggest that structural variability and functional plasticity of microbial communities influence HAB trajectory.

阐明藻类与相关微生物群落之间的相互作用对于理解介导海洋环境中有害藻华（HAB）动态的机制至关重要。然而，HABs过程中的微生物功能概况及其生物地球化学潜力仍然难以捉摸，尤其是在完整的天然HAB循环过程中。在这里，我们使用焦磷酸测序和功能基因阵列（GeoChip）来研究天然鞭毛甲藻（夜光藻）中的微生物群落动态和代谢潜能）盛开。结果表明，浮游细菌在开花阶段的过程中表现出明显的时间异质性。微生物演替是由环境参数和生物相互作用共同驱动的。功能分析揭示了物质循环过程中微生物代谢的显着变化。在开花开始阶段，与铁氧化和转运相关的代谢潜能升高。在高原期，碳的固定和降解，反硝化，磷的吸收以及硫的转移/氧化显着增强。在下降和最终阶段，氧化应激，化合物裂解以及毒素降解和蛋白酶合成增加。这项工作表明，藻圈微生物可以增强有机碳的分解能力，改变氮的同化率和S / P转换效率，HAB过程中的铁预算平衡。生态联系分析进一步表明，微生物组成和功能潜力与藻华的发生显着相关。这表明微生物群落的结构变异性和功能可塑性影响着HAB的轨迹。