有害藻华期间微生物与浮游生物群落的季节动态及生态互作研究

本研究通过分析韩国统营（TY）与丽水（YS）海域的微生物与浮游生物群落季节动态，揭示了藻华期间营养级调控机制（top-down与bottom-up控制）的交互作用，强调了浮游动物摄食（top-down）与细菌再矿化在维持生态系统平衡中的关键角色，为有害藻华（HABs）的生态预测与管理提供了科学依据。

　　

Highlight

This study investigates the seasonal dynamics of microbial and plankton communities in Tongyeong (TY) and the Bodol Sea near Yeosu (YS), South Korea, focusing on the interactions during algal blooms and their ecological implications. In May at TY, moderate chlorophyll a (Chl-a) and high copepod abundance suggest top-down control by zooplankton grazing, rather than nutrient limitation, regulates phytoplankton biomass. Microbial communities resembled those during August YS blooms, likely due to enhanced organic matter from grazing. By late summer, reduced nutrients favored Dinoflagellata and Ochrophyta indicating weakened grazing pressure and greater microbial diversity.

本研究探究了韩国统营（TY）与丽水（YS）附近宝多尔海域微生物与浮游生物群落的季节动态，重点关注藻华期间的生态互作及其意义。五月在TY海域，中等水平的叶绿素a（Chl-a）与高桡足类丰度表明，浮游动物摄食（top-down控制）而非营养限制调控了浮游生物量；其微生物群落与八月YS藻华期间相似，可能源于摄食活动促进的有机物输入。至夏末，营养盐减少使甲藻门（Dinoflagellata）与褐藻门（Ochrophyta）占优，反映出摄食压力减弱和微生物多样性升高。

In August at YS, a harmful Cochlodinium bloom dominated offshore waters, while diatoms prevailed nearshore. Elevated Chl-a, oversaturated oxygen, and low copepod abundance indicated disrupted trophic balance during the blooming. Cochlodinium correlated strongly with bacteria such as Pseudoaltermonas and Vibrio, reflecting responses to high productivity. After the bloom decline in September, Syndiniales (parasitic dinoflagellates) increased, suggesting predator-prey regulation of algal populations. Bacterial remineralization supported nutrient cycling, maintaining ecosystem balance.

八月在YS海域，离岸水域暴发有害旋沟藻（Cochlodinium）华，而近岸则以硅藻为主。高Chl-a、过饱和溶解氧与低桡足类丰度表明藻华期间营养平衡被破坏；旋沟藻与假交替单胞菌（Pseudoaltermonas）和弧菌（Vibrio）等细菌显著相关，反映出对高生产力的响应。九月藻华衰退后，寄生性甲藻Syndiniales增多，暗示藻类种群受捕食-被捕食关系调控；细菌再矿化作用支撑了营养循环，维持了生态平衡。

Contrasting responses to high productivity were observed: TY exhibited strong top-down control without biomass accumulation, whereas YS experienced significant biomass buildup during the bloom. Despite these differences, the microbial communities in both systems were similar and reflected the degree of productivity more accurately than the primary producers themselves. Overall, these results highlight the complex interactions among primary producers, grazers, and microbes, emphasizing the critical role of trophic dynamics in shaping coastal bloom events.

两地对高生产力呈现出迥异响应：TY表现出强top-down控制且无生物量累积，而YS则在藻华期间出现显著生物量积累。尽管存在差异，两系统的微生物群落却相似，且比初级生产者本身更准确地反映了生产力水平。总体而言，这些结果凸显了初级生产者、摄食者与微生物间的复杂互作，强调了营养动力学在塑造海岸藻华事件中的关键作用。

Conclusions

Our study reveals how top-down (zooplankton grazing) and bottom-up (nutrient-driven) forces interact to shape marine ecosystems (Table 2). Shifts in phytoplankton (Cochlodinium to Syndiniales), microbial taxa (Vibrio dominance), and nutrient fluxes underscore the adaptability of the ecosystem. Microbial communities exhibited resilience, driving nutrient recycling and maintaining stability even during HABs and seasonal shifts. A comprehensive analysis of interactions among three trophic

本研究揭示了top-down（浮游动物摄食）与bottom-up（营养驱动）力量如何交互塑造海洋生态系统。浮游植物（从旋沟藻到Syndiniales）、微生物类群（如弧菌优势）与营养通量的变化突显了生态系统的适应性。微生物群落展现出韧性，驱动营养再循环并在有害藻华（HABs）与季节更替中维持稳定。对三个营养级间互作的综合分析