De-intensification Effects on Methane-Cycling Microorganisms and the Methane Sink Function of Grasslands (MetGrass)

对甲烷循环微生物和草原甲烷汇功能的去强化效应（MetGrass）

• 批准号: 512405836
• 负责人: Professor Dr. Steffen Kolb
• 金额: --
• 依托单位: Fachgebiet Bodenbiologie (310b)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/512405836?language=en
• 关键词: De; intensification; Effects; Methane; Cycling

Methane (CH4) is the second most relevant greenhouse gas and contributes substantially to global warming. In 2021, global political efforts have been started to mitigate its emission. The soil microbiome is the most important terrestrial methane sink, but this is highly dependent on land use management. A major challenge for today´s agriculture is to adjust land-use intensity to ensure productive and at the same time sustainable grassland production systems to balance greenhouse gas emissions and increasing food demands of a growing world population. Two fundamentally different groups of microbes are crucial for CH4-cycling. Methanotrophic bacteria act as biological sink by oxidizing atmospheric CH4, while methanogens produce methane in anoxic zones, aggregates and deeper soil layers. In the previous project, the partners have revealed (1) the negative impact of high land-use intensity on methanotrophic bacteria in grassland soils, and (2) the high seasonal microbiome dynamics that determine if grasslands are sources or sinks of CH4. The results raise several questions regarding the magnitude and dynamics of land-use intensity effects on CH4-cycling microbiomes and the resulting net surface fluxes. In the new proposal MetGrass, we will thus study the effects of grassland land-use de-intensification on methanotrophs and methanogens, by contributing to the joint multi-site grassland experiments REX and LUX. How a reduction of fertilization, mowing, and grazing will impact biodiversity, activity, abundance and the distribution over the soil profile of methanotrophs and methanogens hast not been investigated in any ecosystem-scale experiment to date. We will test four complementary hypotheses with the overall aim to assess (1) how de-intensification leads to changes of the species composition and abundance of methanogenic and methanotrophic microbes, (2) how this is associated with changed CH4 net surface fluxes and (3) how rapid these changes are. In work package (WP)1, we will study the long-term recovery effects of the CH4 sink function and methanotrophs in grassland soils after de-intensification. WP2 assesses short-term responses of methanotrophs and methanogens to single management events (i.e. fertilization and mowing). In WP3, we aim to develop microbiome-based predictive model of grassland soil CH4 fluxes. WP4 will assess the tipping point of the CH4 sink function of a grassland soil upon increasing rates of fertilization and will thereby provide a mechanistic understanding of underlying microbiome dynamics. We will employ a unique combination of state-of-the-art approaches, reflecting the interdisciplinary nature of the MetGrass team. MetGrass will be able (a) to address pressing questions on the effect of land-use de-intensification on the functional diversity and activity of these key soil microorganisms in grasslands and (b) will deliver the basis for improvement of grassland management towards sustainable land use.

甲烷（CH4）是第二最相关的温室气体，并为全球变暖做出了重大贡献。 2021年，全球政治努力开始减轻其排放。土壤微生物组是最重要的陆甲烷水槽，但这高度取决于土地利用管理。当今农业的一个主要挑战是调整土地利用强度，以确保可持续的草地生产系统的生产力和可持续的草地生产系统，以平衡温室气体排放和不断增长的世界人口的粮食需求。两个根本不同的微生物组对于CH4循环至关重要。甲嗜营养细菌通过氧化大气CH4充当生物下沉，而甲烷元素在缺氧区，聚集物和更深的土壤层中产生甲烷。在上一个项目中，合作伙伴揭示了（1）高土地使用强度对草原土壤中甲烷营养细菌的负面影响，以及（2）确定草地是CH4的来源还是下沉的季节性微生物组动力学。结果提出了几个问题，内容涉及土地利用强度对CH4循环微生物组和所得净表面通量的幅度和动态。在新的提案元草中，我们将通过为联合多站点的草原实验Rex和Lux做出贡献，从而研究草地土地利用去义对甲烷营养和甲烷的影响。尚未在迄今为止的任何生态系统规模的实验中研究受精，割草和梯度的减少如何影响生物多样性，活性，抽象以及在甲烷营养和甲烷植物土壤谱的分布。我们将测试四个完整的假设，其总体目的是评估（1）脱敏化如何导致物种组成的变化和甲烷基因和甲嗜营养不良的微生物的变化，（2）与CH4净表面通量变化以及（3）这些变化的速度有多快。在工作包（WP）1中，我们将研究CH4水槽功能的长期恢复作用和脱糊化后草地土壤中的甲烷营养作用。 WP2评估甲烷营和甲烷植物对单个管理事件的短期反应（即受精和割草）。在WP3中，我们旨在开发基于微生物组的草原土壤CH4通量的预测模型。 WP4将随着受精速率增加，将评估草原土壤的CH4水槽功能的临界点，从而提供对潜在的微生物组动力学的机械理解。我们将采用最先进的方法的独特组合，以反映梅格拉斯团队的跨学科性质。梅特格拉斯将能够（a）解决有关土地利用去授课对这些关键土壤微生物在草原的功能多样性和活动影响的迫切问题，（b）将为改善草原管理对可持续土地使用的基础。