Wang Jing, Peipoch Marc, Guo Xiaoxiao, Kan Jinjun
Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China.
Stroud Water Research Center, Avondale, PA, United States.
Front Microbiol. 2022 Sep 16;13:991816. doi: 10.3389/fmicb.2022.991816. eCollection 2022.
Biofilm communities play a major role in explaining the temporal variation of biogeochemical conditions in freshwater ecosystems, and yet we know little about how these complex microbial communities change over time (aka succession), and from different initial conditions, in comparison to other stream communities. This has resulted in limited knowledge on how biofilm community structure and microbial colonization vary over relevant time scales to become mature biofilms capable of significant alteration of the freshwater environment in which they live. Here, we monitored successional trajectories of biofilm communities from summer and winter in a headwater stream and evaluated their structural state over time by DNA high-throughput sequencing. Significant differences in biofilm composition were observed when microbial colonization started in the summer vs. winter seasons, with higher percentage of algae (Bacillariophyta) and Bacteroidetes in winter-initiated samples but higher abundance of Proteobacteria (e.g., Rhizobiales, Rhodobacterales, Sphingomonadales, and Burkholderiales), Actinobacteria, and Chloroflexi in summer-initiated samples. Interestingly, results showed that despite seasonal effects on early biofilm succession, biofilm community structures converged after 70 days, suggesting the existence of a stable, mature community in the stream that is independent of the environmental conditions during biofilm colonization. Overall, our results show that algae are important in the early development of biofilm communities during winter, while heterotrophic bacteria play a more critical role during summer colonization and development of biofilms.
生物膜群落对于解释淡水生态系统中生物地球化学条件的时间变化起着重要作用，然而，相较于其他溪流群落，我们对这些复杂的微生物群落如何随时间变化（即演替）以及从不同初始条件下的变化了解甚少。这导致我们对生物膜群落结构和微生物定殖在相关时间尺度上如何变化以形成能够显著改变其生存淡水环境的成熟生物膜的认识有限。在此，我们监测了一条源头溪流中夏季和冬季生物膜群落的演替轨迹，并通过DNA高通量测序评估了它们随时间的结构状态。当微生物定殖始于夏季和冬季时，观察到生物膜组成存在显著差异，冬季起始样本中藻类（硅藻门）和拟杆菌门的百分比更高，而夏季起始样本中变形菌门（如根瘤菌目、红杆菌目、鞘脂单胞菌目和伯克霍尔德菌目）、放线菌门和绿弯菌门的丰度更高。有趣的是，结果表明，尽管季节对早期生物膜演替有影响，但生物膜群落结构在70天后趋同，这表明溪流中存在一个稳定、成熟的群落，其独立于生物膜定殖期间的环境条件。总体而言，我们的结果表明，藻类在冬季生物膜群落的早期发育中很重要，而异养细菌在夏季生物膜定殖和发育过程中发挥更关键的作用。
