Differential responses of total and active soil microbial communities to long-term experimental N deposition
Differential responses of total and active soil microbial communities to long-term experimental N deposition
复制标题
DOI：
10.1016/j.soilbio.2015.08.014
复制
发表时间：
2015-11-01
影响因子：
9.7
通讯作者：
Zak, Donald R.
中科院分区：
文献类型：
--
作者：
Freedman, Zachary B.;Romanowicz, Karl J.;Zak, Donald R.
土壤总微生物群落与代谢活性微生物群落之间的关系可以深入了解这些群落如何受到环境变化的影响，这可能会影响未来的能量流动和养分循环。例如，在过去150年中，人为释放的生物可利用氮急剧增加，这可能改变陆地生态系统中控制碳储存的过程。在美国密歇根州北部阔叶林生态系统中，近20年实验增加的大气氮沉降减少了森林地面腐烂，增加了土壤C储量。微生物机制是这种反应的基础，因为土壤微生物群落的组成变化与这些生物地球化学变化同时被记录下来。在这里，我们从腐烂的凋落叶中共同提取DNA和RNA，以确定实验性大气氮沉降是否降低了细菌和真菌（即基于DNA的）及其活性成员（即基于RNA的）群落的多样性和组成。在我们的实验中，实验N沉降没有影响森林地面真菌群落的组成、多样性和丰富度，但降低了森林地面真菌群落的多样性（-8%），并改变了活跃真菌群落的组成。相反，试验N沉降对森林地表细菌群落总量和活性均无显著影响。我们的研究结果表明，未来大气氮沉降速率可以从根本上改变腐坏性土壤真菌群落的组织，而真菌群落是陆地环境中碳循环的关键媒介。(C) 2015 Elsevier Ltd.版权所有。
The relationship between total and metabolically active soil microbial communities can provide insight into how these communities are impacted by environmental change, which may impact the flow of energy and cycling of nutrients in the future. For example, the anthropogenic release of biologically available N has dramatically increased over the last 150 years, which can alter the processes controlling C storage in terrestrial ecosystems. In a northern hardwood forest ecosystem located in Michigan, USA, nearly 20 years of experimentally increased atmospheric N deposition has reduced forest floor decay and increased soil C storage. A microbial mechanism underlies this response, as compositional changes in the soil microbial community have been concomitantly documented with these biogeochemical changes. Here, we co-extracted DNA and RNA from decaying leaf litter to determine if experimental atmospheric N deposition has lowered the diversity and altered the composition of the whole communities of bacteria and fungi (i.e., DNA-based) and well as its active members (i.e., RNA-based). In our experiment, experimental N deposition did not affect the composition, diversity, or richness of the total forest floor fungal community, but did lower the diversity (-8%), as well as altered the composition of the active fungal community. In contrast, neither the total nor active forest floor bacterial community was significantly affected by experimental N deposition. Our results suggest that future rates of atmospheric N deposition can fundamentally alter the organization of the saprotrophic soil fungal community, key mediators of C cycling in terrestrial environments. (C) 2015 Elsevier Ltd. All rights reserved.