Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Sichuan, 610041, China.
Earth and Biological Sciences Directorate, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
Sci Rep. 2017 Dec 13;7(1):17492. doi: 10.1038/s41598-017-17736-w.
How press disturbance (long-term) influences the phylogenetic turnover of soil microbial communities responding to pulse disturbances (short-term) is not fully known. Understanding the complex connections between the history of environmental conditions, assembly processes and microbial community dynamics is necessary to predict microbial response to perturbation. We started by investigating phylogenetic spatial turnover (based on DNA) of soil prokaryotic communities after long-term nitrogen (N) deposition and temporal turnover (based on RNA) of communities responding to pulse by conducting short-term rewetting experiments. The results showed that moderate N addition increased ecological stochasticity and phylogenetic diversity. In contrast, high N addition slightly increased homogeneous selection and decreased phylogenetic diversity. Examining the system with higher phylogenetic resolution revealed a moderate contribution of variable selection across the whole N gradient. The moisture pulse experiment showed that high N soils had higher rates of phylogenetic turnover across short phylogenetic distances and significant changes in community compositions through time. Long-term N input history influenced spatial turnover of microbial communities, but the dominant community assembly mechanisms differed across different N deposition gradients. We further revealed an interaction between press and pulse disturbances whereby deterministic processes were particularly important following pulse disturbances in high N soils.
长期的压力干扰（如氮沉降）如何影响土壤微生物群落对短期脉冲干扰（如水分脉冲）的系统发育周转率尚不完全清楚。为了预测微生物对干扰的响应，理解环境条件历史、组装过程和微生物群落动态之间的复杂联系是必要的。我们首先通过进行短期复湿实验，调查了长期氮（N）添加后土壤原核微生物群落的基于 DNA 的系统发育空间周转率（phylogenetic spatial turnover）和对脉冲响应的基于 RNA 的时间周转率（temporal turnover）。结果表明，适度的 N 添加增加了生态随机性和系统发育多样性。相比之下，高 N 添加略微增加了同质性选择，降低了系统发育多样性。通过更高系统发育分辨率的系统检验发现，在整个 N 梯度上，可变选择的贡献适中。水分脉冲实验表明，高 N 土壤在短系统发育距离上具有更高的系统发育周转率，并且随着时间的推移群落组成发生显著变化。长期的 N 输入历史影响了微生物群落的空间周转率，但不同 N 沉降梯度下的主要群落组装机制不同。我们进一步揭示了压力和脉冲干扰之间的相互作用，即在高 N 土壤中，脉冲干扰后，确定性过程尤为重要。
