Integrated approach for analyzing water-microbe-DOC-oxygen interaction in soil micropores

分析土壤微孔中水-微生物-DOC-氧相互作用的综合方法

• 批准号: RGPIN-2019-07071
• 负责人: Wang, Junye
• 金额: $ 1.78万
• 依托单位: Athabasca University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715709
• 关键词: Integrated; approach; analyzing; water; microbe

Dissolved organic carbon (DOC) is one of the most important mobile types of carbon environmentally, because it can become stabilized in soils. Increasing evidence shows that soil effects are dominating carbon cycling processes, particularly in relation to DOC. Storing DOC in soil is thus an approach to mitigate global warming. However, directly measuring how DOC is stored and moves in soil and how water, DOC, and microbes interact below ground is very difficult. Moreover, soil architectures and microbial activities are spatially heterogeneous from the micro-scale to the field scale. Consequently, many questions remain regarding DOC at the soil-pore scale. For example, is the pore scale merely an environment in which DOC adsorbs or desorbs to soil aggregates, or do the local microbewaterDOCpore structure interactions have emergent phenomena unique to this scale? Are there any phenomena at this scale that cannot be addressed in large-scale process-based models and interpretations? The pore scale is important because biogeochemical processes such as watermicroorganismDOC interactions and transport occur within the pores of the soil, giving rise to new biogeochemical behaviour that might not be understood or predicted by considering smaller or larger scales alone. Therefore, quantifying the changes happening in soil pores will be crucial for understanding the dynamics of DOC stabilization. This proposal aims to understand how processes that stabilize DOC are driven by water content and flow, spatial heterogeneity in soils, the availability and movement of DOC, and microbial activities in soils. We will simulate all these processes using the lattice Boltzmann model (LBM) embedded with an individual-based model (iBM) and the Dual Arrhenius and MichaelisMenten (DAMM) kinetics model. The lattice Boltzmann codes we have already developed will provide a mathematical framework to simulate multi-species transport and degradation (e.g., DOC, water, oxygen, and product) at the soil-pore scale. The iBM will enable us to simulate microorganism growth and nutrient consumption and to set up experiments for the validation of the model. This analysis of the system will be based on the fundamental laws of physics, chemistry, and biology; it will enforce quantitative and comprehensive clarification of concepts and assumptions; and it will impose rational methods for approaching the problem. Our results will provide not only a detailed comparison of DOC stabilization in homogeneous and heterogeneous soil architectures but also quantifying influence of soil heterogeneity on DOC stabilization calculated using the DAMM. This knowledge could help to mitigate global warming by enabling the storage of greater levels of DOC in soil.

溶解有机碳（DOC）是环境中最重要的移动的碳类型之一，因为它可以在土壤中变得稳定。越来越多的证据表明，土壤的影响是主导碳循环过程，特别是在DOC。因此，在土壤中储存DOC是减缓全球变暖的一种方法。 然而，直接测量DOC如何在土壤中储存和移动，以及水，DOC和微生物如何在地下相互作用是非常困难的。此外，从微观尺度到田间尺度，土壤结构和微生物活动在空间上是异质的。因此，许多问题仍然存在关于DOC在土壤孔隙尺度。例如，孔隙尺度仅仅是DOC吸附或解吸到土壤团聚体中的环境，还是局部微生物-水-DOC-孔隙结构相互作用具有该尺度特有的涌现现象？在这种规模下，是否有任何现象无法在基于过程的大规模模型和解释中解决？ 孔隙尺度是重要的，因为水-微生物-DOC相互作用和运输等地球化学过程发生在土壤孔隙内，产生了新的地球化学行为，这些行为可能无法通过单独考虑较小或较大的尺度来理解或预测。因此，量化土壤孔隙中发生的变化将是至关重要的DOC稳定的动态理解。 该提案旨在了解如何稳定DOC的过程是由水含量和流量，土壤中的空间异质性，DOC的可用性和运动，以及土壤中的微生物活动驱动的。我们将模拟所有这些过程中使用的晶格玻尔兹曼模型（LBM）嵌入了基于个人的模型（iBM）和双Arrhenius和MichaelisMenten（DAMM）动力学模型。我们已经开发的格子玻尔兹曼代码将提供一个数学框架来模拟多物种的运输和降解（例如，DOC、水、氧和产物）。iBM将使我们能够模拟微生物的生长和营养消耗，并建立实验来验证模型。对系统的这种分析将以物理、化学和生物学的基本定律为基础;它将加强对概念和假设的定量和全面的澄清;它将强加理性的方法来处理问题。我们的研究结果将提供不仅是一个详细的比较DOC稳定在均质和非均质土壤结构，但也量化的影响土壤异质性DOC稳定使用DAMM计算。这些知识可以通过在土壤中储存更高水平的DOC来帮助缓解全球变暖。