Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiang'an South Road, Xiamen, Fujian 361102, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian 361021, China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian 361021, China.
Sci Total Environ. 2021 Sep 1;785:147298. doi: 10.1016/j.scitotenv.2021.147298. Epub 2021 Apr 24.
Wetting-drying cycles typically result in a wide range of soil moistures and redox potentials (Eh) that significantly affect the soil microbial community. Although numerous studies have addressed the effects of soil moisture on soil microbial community structure and composition, the response of active microbes to the fluctuation in soil Eh is still largely unknown; this is especially true for the ecological roles of abundant and rare taxa. To explore the dynamics of active and total microbial communities in response to wetting-drying cycles, we conducted a microcosm experiment based on three wetting-drying cycles and 16S rRNA transcript (active) and 16S rRNA gene (total) amplicon sequencing. We found that both active and total microbial communities during three wetting-drying cycles were clustered according to the number of wetting-drying cycles (temporal factor) rather than soil moisture or Eh. Dynamics of the active microbial community, however, were redox dependent during the first wetting-drying cycle. In addition, rare taxa in the active microbial community exhibited more obvious differences than abundant ones during three wetting-drying cycles. Species turnover of abundant and rare taxa of total and active microbes, rather than species richness, explained the highest percentage of community variation. Rare taxa exhibited the most marked temporal turnover during three wetting-drying cycles. Members of Rhodospirillaceae were the major contributor to the resilience of abundant taxa of active microbes during the first wetting-drying cycle. Overall, these findings expand our current understanding of underlying assembly mechanisms of soil microbial communities responding to wetting-drying cycles.
干湿循环通常会导致土壤湿度和氧化还原电位（Eh）的大范围变化，这会显著影响土壤微生物群落。尽管许多研究已经探讨了土壤水分对土壤微生物群落结构和组成的影响，但对于活跃微生物对土壤 Eh 波动的响应，人们仍然知之甚少；对于丰富和稀有类群的生态作用，更是如此。为了探索活跃和总微生物群落对干湿循环的响应动态，我们进行了一项基于三个干湿循环和 16S rRNA 转录（活跃）和 16S rRNA 基因（总）扩增子测序的微宇宙实验。我们发现，在三个干湿循环过程中，活跃和总微生物群落都是根据干湿循环的次数（时间因素）而不是土壤湿度或 Eh 聚类的。然而，在第一个干湿循环中，活跃微生物群落的动态是依赖于氧化还原的。此外，在三个干湿循环过程中，活跃微生物群落中的稀有类群比丰富类群表现出更明显的差异。总微生物和活跃微生物中丰富和稀有类群的物种周转率，而不是物种丰富度，解释了群落变化的最高百分比。稀有类群在三个干湿循环过程中表现出最显著的时间周转率。在第一个干湿循环中，红螺菌科的成员是活跃微生物丰富类群恢复力的主要贡献者。总的来说，这些发现扩展了我们对土壤微生物群落响应干湿循环的潜在组装机制的现有理解。
