Thermodynamics of microbial turnover of organic compounds in soil - matter and energy flux under varying environmental conditions (water, nutrient availability, temperature) – TherMic

土壤中有机化合物的微生物周转的热力学 - 不同环境条件（水、养分利用率、温度）下的物质和能量通量 â TherMic

• 批准号: 465119920
• 负责人: Privatdozent Dr. Thomas Maskow
• 金额: --
• 依托单位: Department Umweltbiotechnologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465119920?language=en
• 关键词: Thermodynamics; microbial; turnover; organic; compounds

Soil microbial communities are both drivers of soil organic matter (SOM) dynamics and dominant contributors to SOM. They modulate soil carbon dynamics and fluxes through microbial biomass along different flux channels finally resulting in stabilised necromass in SOM. The basic hypothesis of SPP 2223 thus is that most of the C flux towards SOM pass through microbial biomass, which needs energy for growth and maintenance. Energy consideration of soil processes based on thermodynamic principles is needed, since huge amounts of solar energy pass through soil and are partly conserved in SOM. During microbial metabolism, parts of the organic substrates are used for energy delivery (catabolism) and energy conservation by biomass formation (anabolism). In addition, small amounts of nutrients and biomolecules in soils may result in higher biomass yields from a growth substrate, because less energy is needed for biomass compound synthesis. Microbial energy use efficiency (EUE) and carbon use efficiency (CUE), i.e. the balance of anabolic versus catabolic processes, are thus the overarching determinants of microbial turnover of organic substrates in soils and retention of C and energy in SOM. Boundary conditions, including temperature, soil moisture, bulk density (gas diffusion), and nutrient availability, strongly effect the relation between matter and energy flux and thus CUE and EUE. Therefore, the present core project TherMic aims at directly linking thermodynamics to microbial mass turnover and growth and alterations of microbial communities as well as at studying the effect of boundary conditions on matter and energy turnover in soil systems. TherMic addresses this objective by laboratory incubation studies with simultaneous analysis of carbon and energy fluxes from selected substrates (cellulose, peptidoglycan). We use isotope-labelled substrates to follow the flux of C through the system combined with calorimetry to assess energy balances. Incubations at different boundary conditions allow to study the effect of temperature, soil moisture and nutrient availability on mass and energy fluxes and balances. In addition, for broader application of simultaneous analysis of matter and energy fluxes, we develop a calorimeter for application in standardised soil tests. Finally, all our results are used to develop models describing and predicting C and energy fluxes on the basis of energy and mass balance data.The results from TherMic are complemented by collaboration within the SPP, in particular with the other core projects analysing microbial communities and trophic networks in the proposed experiments. At the end, TherMic will allow a better understanding of turnover processes and estimating how much of the potentially available energy can actually be used under given soil conditions.

土壤微生物群落既是土壤有机质动态的驱动者，又是土壤有机质的主要贡献者。它们通过微生物生物量沿着不同的通量通道调节土壤碳动态和通量，最终导致SOM中稳定的坏死物。沿着不同的通量通道。因此，SPP 2223的基本假设是，流向SOM的大部分C通量通过微生物生物量，微生物生物量需要能量来生长和维持。由于大量的太阳能穿过土壤并部分保存在土壤有机质中，因此需要基于热力学原理考虑土壤过程的能量。在微生物代谢过程中，部分有机基质用于能量传递（catalytic）和通过生物质形成（analytic）来保存能量。此外，土壤中的少量营养物和生物分子可导致来自生长基质的更高的生物质产量，因为生物质化合物合成需要更少的能量。因此，微生物能量利用效率（埃厄）和碳利用效率（CUE），即合成代谢与分解代谢过程的平衡，是土壤中有机基质微生物周转以及有机质中碳和能量保留的首要决定因素。边界条件，包括温度，土壤水分，体积密度（气体扩散），养分有效性，强烈影响之间的关系，物质和能量通量，从而CUE和埃厄。因此，目前的核心项目ThermMic旨在将热力学与微生物质量周转以及微生物群落的生长和改变直接联系起来，并研究边界条件对土壤系统中物质和能量周转的影响。ThermMic通过实验室培养研究解决了这一目标，同时分析了来自选定底物（纤维素，肽聚糖）的碳和能量通量。我们使用同位素标记的基板，通过系统结合量热法，以评估能量平衡的C通量。在不同的边界条件下进行培养，可以研究温度、土壤湿度和养分供应对物质和能量通量及平衡的影响。此外，为了更广泛地应用于物质和能量通量的同时分析，我们开发了一种用于标准化土壤测试的量热仪。最后，我们所有的研究结果被用来开发模型，描述和预测的基础上的能量和质量平衡数据的C和能量fluxs.The结果从Thermic补充SPP内部的合作，特别是与其他核心项目分析微生物群落和营养网络在拟议的实验。最后，ThermMic将允许更好地了解周转过程，并估计在给定的土壤条件下实际可以使用多少潜在的可用能量。