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

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.

人口激增、农业集约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、组成和稳定性，以提高土壤肥力和农业生态系统的可持续性，并建立公平和透明的方法来评估部门对气候的贡献。最近，人们非常关注储存或封存土壤碳。虽然这一目标对于减缓气候变化至关重要，但重要的是要认识到土壤碳不仅需要储存，而且还用于维持植物光合产物。基本的农业生态系统土壤中新碳和新能源的形成是由微生物介导的，这些微生物在分解过程中利用植物碳，释放能量和养分。了解这些微生物转化是土壤有机质的核心。土壤肥力和生产力。它含有支持植物生长的碳和养分，为生物过程提供燃料，为负责的生物群提供栖息地，并缓冲短期压力（例如养分不平衡或干旱）。微生物活动的热点，例如植物残留物表面和土壤团聚体中的微位点，其活跃种群数量比大块土壤高出二十倍。热点是由于丰富的资源可用性而产生的（例如，C）。需要更好地了解执行分解的微生物类群或群落特征的作用，以优化碳循环过程和可持续土壤管理。在富含碳的热点地区，拟议的研究计划将通过三个项目专门研究土壤微生物如何充当碳流的媒介，这三个项目分别解决土壤碳稳定和不稳定的微生物生态学的独立但相关的方面：1）调查之间的关系不同农业土壤中碳利用的热力学效率和微生物群落组成，2）使用富碳埋藏土壤作为模型系统，识别富碳埋藏土壤中碳稳定的指示微生物和SOM生物标志物热点，3) 分析这些富含碳的埋藏土壤的物理尺寸分数和聚集体中的微生物群落和碳周转，以更好地了解微生境作为碳稳定的潜在热点的作用。磷 (P) 和钾 (K) 在土壤肥料管理中得到了广泛认可，将碳明确纳入资源管理策略有可能大大提高肥料利用效率并增强空气和水的关键功能。换句话说，向 CNPK 管理框架的转变将更好地支持可持续土壤管理，并最终支持粮食安全。