Biological carbon stabilization and destabilization: peering into microbial hot spots to understand soil carbon turnover and terrestrial energy flows

生物碳稳定和不稳定：深入研究微生物热点以了解土壤碳周转和陆地能量流

• 批准号: RGPIN-2019-04158
• 负责人: Helgason, Bobbi
• 金额: $ 1.82万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765629
• 关键词: Biological; carbon; stabilization; destabilization; peering; Biological; carbon; stabilization; destabilization; peering

Burgeoning population, agricultural intensification and changing climate are threatening global food security. Understanding the amount, composition and stability of soil carbon (C) is needed to enhance soil fertility and agroecosystem sustainability and to establish a fair and transparent approach to evaluating sector contributions to climate change mitigation. Recently, great focus has been on storing or sequestering soil C. While this goal is critical to climate change mitigation, it is important to recognize that soil C not only needs to be stored, but also used to maintain ecosystem function. Plant photosynthate is the primary source of new C, and thus new energy, in agroecosystem soils. Formation of soil organic matter is mediated by microorganisms that utilize plant C during decomposition, releasing energy and nutrients. Understanding these microbial transformations is critical. Soil organic matter is at the heart of soil fertility and productivity. It holds C and nutrients that support plant growth, fuels biological processes, provides habitat for the biota responsible and buffers against short-term stresses (e.g. nutrient imbalance or drought).       Hot-spots of microbial activity such as plant residue surfaces and microsites within soil aggregates have active populations up to twenty times higher than the bulk soil. Hot spots arise from abundant resource availability (e.g. C). They are temporally dynamic and difficult to study at relevant scales of time and space. Improved understanding of the roles of microbial taxa or community traits that perform decomposition is needed to optimize C cycling processes and for sustainable soil management. To better understand microbial dynamics of C-turnover in C-rich hot spots, the proposed research program will specifically examine how soil microorganisms act as agents of C flows through three projects which address separate, but related aspects of microbial ecology of soil C stabilization and destabilization: 1) a survey of relationships between thermodynamic efficiency of C use and microbial community composition in different agricultural soils, 2) use C-rich buried soils as a model system to identify indicator microorganisms and SOM biomarkers for C-stabilization in C-rich hot-spots, 3) profile microbial communities and C turnover in physical size fractions and aggregates of these C-rich buried soils to better understand the role of microhabitats as potential hot-spots of C stabilization.  The interrelatedness of macronutrients nitrogen (N), phosphorus (P) and potassium (K) is acknowledged in soil fertilizer management. Explicit integration of C into resource management strategies has the potential to greatly enhance fertilizer use efficiency and to bolster critical functions of air and water filtration, climate change mitigation and food production. In other words, a shift toward a CNPK management frameworks will better support sustainable soil management and ultimately, food security.

新兴的人口，农业强化和气候变化正在威胁全球粮食安全。需要了解土壤碳（C）的数量，成分和稳定性，以增强土壤的生育能力和农业生态系统的可持续性，并建立一种公平，透明的方法来评估对气候变化缓解气候变化的贡献。最近，非常重点是储存或隔离土壤C。尽管该目标对于缓解气候变化至关重要，但重要的是要认识到，土壤C不仅需要存储，而且还用于维持生态系统功能。在农业生态系统土壤中，植物光合物是新C，因此是新能量的主要来源。土壤有机物的形成是由在分解过程中利用植物C的微生物介导的，释放了能量和养分。了解这些微生物转化至关重要。土壤有机物是土壤肥力和生产力的核心。它拥有支持植物生长的C和营养，燃料生物过程，为生物群体提供了栖息地，可为短期应力（例如，营养失衡或干旱）提供栖息地和缓冲剂。微生物活性的热点，例如植物保留表面和土壤聚集体中的微观物，其活性种群的群体比散装土壤高二十倍。热点来自丰富的资源可用性（例如C）。它们是暂时的动态性，很难在相关的时间和空间尺度上进行研究。需要提高对微生物分类单元或执行分解的社区特征的作用的理解，以优化C循环过程和可持续的土壤管理。 To better understand microbial dynamics of C-turnover in C-rich hot spots, the proposed research program will specifically examine how soil microorganisms act as agents of C flows through three projects which address separate, but related aspects of microbial ecology of soil C stabilization and destabilization: 1) a survey of relationships between thermodynamic efficiency of C use and microbial community composition in different agricultural soils, 2) use C-rich buried soils as一个模型系统，用于识别富含C的热点中C稳定的指标微生物和SOM生物标志物，3）谱图微生物群落和C周转，以及这些富含C的埋入土壤的物理尺寸分数和聚集体中的C周转，以更好地理解微生物的作用，以理解微生物的作用。在土壤肥料管理中确认了大量营养素（N），磷（P）和钾（K）的相互关系。将C的明确整合到资源管理策略中有可能大大提高肥料的使用效率，并增强空气和水过滤的关键功能，缓解气候变化和食品生产。换句话说，向CNPK管理框架的转变将更好地支持可持续的土壤管理，并最终支持粮食安全。