Marine Biophysics Unit, Okinawa Institute of Science and Technology (OIST), Okinawa, Japan.
Friday Harbor Laboratories, University of Washington, WA, USA.
Environ Microbiol. 2020 Nov;22(11):4571-4588. doi: 10.1111/1462-2920.15178. Epub 2020 Aug 23.
Climate change scenarios predict tropical cyclones will increase in both frequency and intensity, which will escalate the amount of terrestrial run-off and mechanical disruption affecting coastal ecosystems. Bacteria are key contributors to ecosystem functioning, but relatively little is known about how they respond to extreme storm events, particularly in nearshore subtropical regions. In this study, we combine field observations and mesocosm experiments to assess bacterial community dynamics and changes in physicochemical properties during early- and late-season tropical cyclones affecting Okinawa, Japan. Storms caused large and fast influxes of freshwater and terrestrial sediment - locally known as red soil pollution - and caused moderate increases of macronutrients, especially SiO and PO , with up to 25 and 0.5 μM respectively. We detected shifts in relative abundances of marine and terrestrially derived bacteria, including putative coral and human pathogens, during storm events. Soil input alone did not substantially affect marine bacterial communities in mesocosms, indicating that other components of run-off or other storm effects likely exert a larger influence on bacterial communities. The storm effects were short-lived and bacterial communities quickly recovered following both storm events. The early- and late-season storms caused different physicochemical and bacterial community changes, demonstrating the context-dependency of extreme storm responses in a subtropical coastal ecosystem.
气候变化情景预测，热带气旋的频率和强度都将增加，这将加剧陆地径流和机械破坏对沿海生态系统的影响。细菌是生态系统功能的关键贡献者，但对于它们如何应对极端风暴事件，特别是在近岸亚热带地区，相对知之甚少。在这项研究中，我们结合野外观测和中观实验，评估了日本冲绳受热带气旋影响的早季和晚季的细菌群落动态和理化性质变化。风暴导致大量淡水和陆地沉积物的快速涌入——当地称为红土污染——并导致大量营养物质的适度增加，特别是 SiO 和 PO ，分别高达 25 和 0.5 μM。我们在风暴期间检测到海洋和陆地来源细菌的相对丰度发生了变化，包括珊瑚和人类病原体的假定物种。在中观实验中，仅土壤输入并没有对海洋细菌群落产生实质性影响，这表明径流的其他成分或其他风暴影响可能对细菌群落产生更大的影响。风暴的影响是短暂的，两次风暴事件后，细菌群落迅速恢复。早季和晚季风暴导致了不同的理化性质和细菌群落变化，这表明在亚热带沿海生态系统中，极端风暴的响应具有情境依赖性。
