Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, The Graduate School at Shenzhen, Tsinghua University, Guangdong Province, People's Republic of China.
School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, Shandong Province, People's Republic of China.
Appl Environ Microbiol. 2019 Jul 18;85(15). doi: 10.1128/AEM.00349-19. Print 2019 Aug 1.
Given the ecological significance of microorganisms in algal blooming events, it is critical to understand the mechanisms regarding their distribution under different conditions. We tested the hypothesis that microbial community succession is strongly associated with algal bloom stages, and that the assembly mechanisms are cocontrolled by deterministic and stochastic processes. Community structures and underlying ecological processes of microbial populations (attached and free-living bacteria) at three algal bloom stages (pre-, during, and postbloom) over a complete dinoflagellate bloom were investigated. Both attached and free-living taxa had a strong response to the bloom event, and the latter was more sensitive than the former. The contribution of environmental parameters to microbial variability was 40.2%. Interaction analysis showed that complex positive or negative correlation networks exist in phycosphere microbes. These relationships were the potential drivers of mutualist and competitive interactions that impacted bacterial succession. Null model analysis showed that the attached bacterial community primarily exhibited deterministic processes at pre- and during-bloom stages, while dispersal-related processes contributed to a greater extent at the postbloom stage. In the free-living bacterial community, homogeneous selection and dispersal limitation dominated in the initial phase, which gave way to more deterministic processes at the two later stages. Relative contribution analyses further demonstrated that the community turnover of attached bacteria was mainly driven by environmental selection, while stochastic factors had partial effects on the assembly of free-living bacteria. Taken together, these data demonstrated that a robust link exists between bacterioplankton community structure and bloom progression, and phycosphere microbial succession trajectories are cogoverned by both deterministic and random processes. Disentangling the mechanisms shaping bacterioplankton communities during a marine ecological event is a core concern for ecologists. Harmful algal bloom (HAB) is a typical ecological disaster, and its formation is significantly influenced by alga-bacterium interactions. Microbial community shifts during the HAB process are relatively well known. However, the assembly processes of microbial communities in an HAB are not fully understood, especially the relative influences of deterministic and stochastic processes. We therefore analyzed the relative contributions of deterministic and stochastic processes during an HAB event. Both free-living and attached bacterial groups had a dramatic response to the HAB, and the relative importance of determinism versus stochasticity varied between the two bacterial groups at various bloom stages. Environmental factors and biotic interactions were the main drivers impacting the microbial shift process. Our results strengthen the understanding of the ecological mechanisms controlling microbial community patterns during the HAB process.
鉴于微生物在藻类大量繁殖事件中的生态意义，了解其在不同条件下的分布机制至关重要。我们检验了以下假说，即微生物群落演替与藻类大量繁殖阶段密切相关，且其组装机制受到确定性和随机性过程的共同控制。我们研究了在完整的甲藻大量繁殖过程中，三个藻类大量繁殖阶段（大量繁殖前、大量繁殖中和大量繁殖后）的微生物种群（附着和自由生活细菌）的群落结构和潜在生态过程。附着和自由生活的分类群对繁殖事件均有强烈的响应，且后者比前者更敏感。环境参数对微生物变异性的贡献为 40.2%。相互作用分析表明，在藻际微生物中存在复杂的正或负相关网络。这些关系是影响细菌演替的共生和竞争相互作用的潜在驱动因素。零模型分析表明，附着细菌群落主要在前和大量繁殖期间表现出确定性过程，而扩散相关过程在大量繁殖后阶段贡献更大。在自由生活的细菌群落中，均质选择和扩散限制在初始阶段占主导地位，随后在两个后期阶段更多地出现确定性过程。相对贡献分析进一步表明，附着细菌群落的周转率主要受环境选择驱动，而随机因素对自由生活细菌的组装有部分影响。综上所述，这些数据表明，细菌浮游生物群落结构与繁殖进展之间存在牢固的联系，藻际微生物演替轨迹受确定性和随机性过程的共同控制。阐明海洋生态事件中细菌浮游生物群落形成的机制是生态学家关注的核心问题。有害藻类大量繁殖（HAB）是一种典型的生态灾害，其形成受藻类-细菌相互作用的显著影响。HAB 过程中微生物群落的变化相对较为人知。然而，HAB 过程中微生物群落的组装过程尚不完全清楚，特别是确定性和随机性过程的相对影响。因此，我们分析了 HAB 事件中确定性和随机性过程的相对贡献。自由生活和附着细菌群体对 HAB 均有剧烈响应，且在不同的繁殖阶段，两个细菌群体的决定性与随机性的相对重要性有所不同。环境因素和生物相互作用是影响微生物转移过程的主要驱动因素。我们的研究结果增强了对控制 HAB 过程中微生物群落模式的生态机制的理解。
