Data_Sheet_1_Insignificant Response of Bacterioplankton Community to Elevated pCO2 During a Short-Term Microcosm Experiment in a Subtropical Eutrophic Coastal Ecosystem.zip

Ocean acidification, as one of the major consequences of global climate change, markedly affects multiple ecosystem functions in disparate marine environments from coastal habitats to the deep ocean. Evaluation of the responses of marine microbial community to the increasing partial pressure of CO2 (pCO2) is crucial to explore the microbe-driven biogeochemical processes in the future ocean. In this study, a microcosm incubation of eutrophic coastal water from Xiamen Bay under elevated pCO2 (about 1,000 μatm) and control (ambient air, about 380–410 μatm) conditions was conducted to investigate the effect of ocean acidification on the natural bacterioplankton community. During the 5-day incubation period, the chlorophyll a concentration and bacterioplankton abundance were not significantly affected by increased pCO2. Hierarchical clustering and non-metric multidimensional scaling analysis based on Bray-Curtis similarity among the bacterioplankton community derived from the 16S rRNA genes revealed an inconspicuous impact of elevated pCO2 on the bacterial community. During the incubation period, Proteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, and Epsilonbacteraeota were predominant in all microcosms. Despite the distinct temporal variation in the composition of the bacterioplankton community during the experimental period, statistical analyses showed that no significant difference was found on bacterioplankton taxa between elevated pCO2 and control, indicating that the bacterioplankton at the population-level were also insensitive to elevated pCO2. Our results therefore suggest that the bacterioplankton communities in the fluctuating and eutrophic coastal ecosystems appear to be adaptable to the short-term elevated pCO2.

海洋酸化，作为全球气候变化的主要后果之一，显著影响从沿海栖息地到深海等多种海洋环境中的多个生态系统功能。评估海洋微生物群落对增加的二氧化碳分压（pCO2）的响应，对于探索未来海洋中微生物驱动的生物地球化学过程至关重要。在本研究中，对来自厦门湾富营养化沿海水体的微型生态系统进行了在升高pCO2（约1,000 μatm）和对照（环境空气，约380–410 μatm）条件下的培养实验，以研究海洋酸化对自然细菌浮游生物群落的影响。在5天的培养期间，叶绿素a浓度和细菌浮游生物丰度并未因pCO2的增加而受到显著影响。基于Bray-Curtis相似性，通过对细菌浮游生物群落中16S rRNA基因的聚类分析和非度量多维尺度分析，揭示了升高pCO2对细菌群落的影响并不显著。在培养期间，所有微型生态系统中的主要细菌类群为变形菌门、拟杆菌门、放线菌门、蓝细菌门和ε-变形菌门。尽管实验期间细菌浮游生物群落的组成存在明显的时空变化，但统计分析表明，在升高pCO2和对照之间，细菌浮游生物类群之间并未发现显著差异，这表明细菌浮游生物在种群水平上对升高pCO2也不敏感。因此，我们的结果表明，在波动且富营养化的沿海生态系统中，细菌浮游生物群落似乎能够适应短期的升高pCO2。