Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Water Res. 2021 Feb 15;190:116776. doi: 10.1016/j.watres.2020.116776. Epub 2020 Dec 23.
Microbe-mediated transformation of dissolved organic matter (DOM) contributes substantially to the carbon dynamics and energy flow of aquatic ecosystems; yet, the temporal dynamics of bacterial communities in response to diverse DOM sources are scarcely known. Here, we supplied four distinct sources of DOM (algae-derived, macrophyte-derived, sewage-derived, and soil-derived) to the same bacterial community to track the effects of these DOM sources on the carbon processing and successional dynamics of bacterial communities. Although by the end of the incubation the proportion of bio-degraded DOM was significantly lower in the soil-derived DOM treatment than for the other sources, rapid initial metabolism of protein-like and aliphatic compounds and increasing aromaticity and humification degree of DOM during the incubation period were observed for all sources. The role of stochastic processes in governing the community assembly decreased substantially from 61.4% on the first day to 16.7% at the end of the incubation. Moreover, stronger deterministic selection and lower temporal turnover rate were observed for the soil-derived than the other DOM sources, indicating stronger environmental filtering by the more aromatic DOM. Significant correlations were also observed between the humification index (HIX) of DOM and bacterial community diversities, co-occurrence patterns, habitat niche breadths, and the contribution of deterministic ecological processes. In addition, we demonstrated that taxa with different abundance patterns all play crucial but different roles in the response to DOM variation. Our results indicate the importance of DOM aromaticity as a predictor of the outcome of different DOM sources on bacterial community dynamics.
微生物介导的溶解有机物质 (DOM) 转化对水生生态系统的碳动态和能量流动有重要贡献；然而，不同 DOM 来源对细菌群落的时间动态变化却知之甚少。在这里，我们向同一细菌群落提供了四种不同来源的 DOM（藻类衍生、大型植物衍生、污水衍生和土壤衍生），以追踪这些 DOM 来源对细菌群落碳处理和演替动态的影响。尽管在培养结束时，土壤衍生 DOM 处理中生物降解 DOM 的比例明显低于其他来源，但在培养期间观察到所有来源的蛋白质样和脂肪族化合物的快速初始代谢，以及 DOM 的芳香度和腐殖化程度增加。在群落组装过程中，随机过程的作用从第一天的 61.4%显著降低到培养结束时的 16.7%。此外，与其他 DOM 来源相比，土壤衍生 DOM 具有更强的确定性选择和更低的时间周转率，表明更芳香的 DOM 具有更强的环境过滤作用。还观察到 DOM 的腐殖化指数 (HIX) 与细菌群落多样性、共存模式、生境生态位宽度以及确定性生态过程的贡献之间存在显著相关性。此外，我们还证明了具有不同丰度模式的分类群在对 DOM 变化的响应中都发挥着至关重要但不同的作用。我们的结果表明 DOM 芳香度作为不同 DOM 来源对细菌群落动态影响的预测因子的重要性。
