Biological controls over the abundances of terrestrial ammonia oxidizers

Aim: Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the primary agents for nitrification, converting ammonia (NH4+) into nitrate (NO3-) and modulating plant nitrogen (N) utilization and terrestrial N retention. However, there is still lack of a unifying framework describing the patterns of global AOA and AOB distribution. In particular, biotic interactions are rarely integrated into any of the conceptual models. Location: World-wide. Time period: 2005-2016. Major taxa studied: Ammonia-oxidizing archaea and ammonia-oxidizing bacteria. Methods: A meta-analysis and synthesis was conducted to obtain a general picture of global AOA and AOB distribution and identify the primary driving factors. A microcosm experiment was then conducted to assess effects of relative carbon to nitrogen availability for heterotrophic microbes on AOA and AOB in two distinct soils. A mesocosm experiment was further carried out to characterize the effects of plant roots and their arbuscular mycorrhiz...研究目标：氨氧化古菌（Ammonia-oxidizing archaea, AOA）与氨氧化细菌（Ammonia-oxidizing bacteria, AOB）是硝化作用（nitrification）的核心介导类群，可将铵态氮（NH₄⁺）转化为硝态氮（NO₃⁻），进而调控植物氮素利用效率与陆地生态系统氮固持能力。然而当前仍缺乏能够阐明全球AOA与AOB分布格局的统一理论框架，且现有概念模型极少纳入生物相互作用这一关键维度。 研究区域：全球范围 研究时段：2005年—2016年 研究类群：氨氧化古菌与氨氧化细菌。 研究方法：本研究首先通过元分析（meta-analysis）与综合研究，明晰全球AOA与AOB的分布特征并识别其主要驱动因子；随后设置微宇宙实验（microcosm experiment），评估两种不同土壤中异养微生物（heterotrophic microbes）的碳氮相对有效性对AOA与AOB的影响；进一步开展中宇宙实验（mesocosm experiment），以解析植物根系及其丛枝菌根（arbuscular mycorrhiz...）的作用效应。