The Global Distribution, Formation, and Fate of Mineral‐Associated Soil Organic Matter Under a Changing Climate – A Trait‐Based Perspective
The Global Distribution, Formation, and Fate of Mineral‐Associated Soil Organic Matter Under a Changing Climate – A Trait‐Based Perspective
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DOI：
10.1111/1365-2435.14040
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发表时间：
2022-03
影响因子：
5.2
通讯作者：
N. Sokol;E. Whalen;Andrea Jilling;C. Kallenbach;J. Pett‐Ridge;K. Georgiou
中科院分区：
文献类型：
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作者：
N. Sokol;E. Whalen;Andrea Jilling;C. Kallenbach;J. Pett‐Ridge;K. Georgiou
土壤有机质（SOM）是陆地碳(C)最大的活跃循环库，地球矿质土壤中大部分有机质（~65%）是矿物伴生有机质（MAOM）。因此，MAOM的形成和命运可以对全球C循环产生实质性影响。为了预测未来地球气候的变化，从机制上理解MAOM形成和分解的过程，并在生物地球化学和地球系统模型中准确地表达基于这一过程的理解是至关重要的。本文以植物、土壤微生物和矿物基质在调控MAOM形成和分解过程中的相互作用为基础，综述了植物、土壤微生物和矿物基质在MAOM形成和分解中的相互作用。我们提出的框架区分了影响土壤有机质总输入的植物和微生物性状（“原料性状”）与影响最终纳入有机质的有机质输入比例的性状（“有机质形成性状”）。我们讨论了这些原料和MAOM形成特征如何被变暖、降水改变和二氧化碳升高改变。在全球尺度上，这些原料和MAOM形成特征有助于塑造MAOM在地球生物群系中的分布，并调节MAOM对气候变化的生物群系特异性响应。我们利用全球合成的MAOM测量值来估计全球MAOM - C总量（~ 840-1540 Pg C，占陆地总有机C的34%-51%）及其在地球生物群系中的分布。研究表明，MAOM - C浓度在温带森林和草原中最高，在灌丛和稀树草原中最低。草地和农田土壤有机碳（SOC）在MAOM组分（即MAOM - C:SOC比）中所占比例最高，而寒带森林和冻土带的MAOM - C:SOC比最低。利用我们的性状框架，我们回顾了实验数据，并假设气候变化对不同生物群系的MAOM池的影响。最后，我们讨论了如何将MAOM整合到土壤C模型中，以及如何将原料和MAOM形成特征包含在这些模型中。我们还总结了在气候变化情景下MAOM的预估命运（代表性浓度路径4.5和8.5），并讨论了关键的模式不确定性。在《华尔街日报》博客上阅读免费的《简明语言摘要》。
Soil organic matter (SOM) is the largest actively cycling reservoir of terrestrial carbon (C), and the majority of SOM in Earth's mineral soils (~65%) is mineral‐associated organic matter (MAOM). Thus, the formation and fate of MAOM can exert substantial influence on the global C cycle. To predict future changes to Earth's climate, it is critical to mechanistically understand the processes by which MAOM is formed and decomposed, and to accurately represent this process‐based understanding in biogeochemical and Earth system models.In this review, we use a trait‐based framework to synthesize the interacting roles of plants, soil micro‐organisms, and the mineral matrix in regulating MAOM formation and decomposition. Our proposed framework differentiates between plant and microbial traits that influence total OM inputs to the soil (‘feedstock traits’) versus traits that influence the proportion of OM inputs that are ultimately incorporated into MAOM (‘MAOM formation traits’). We discuss how these feedstock and MAOM formation traits may be altered by warming, altered precipitation and elevated carbon dioxide.At a planetary scale, these feedstock and MAOM formation traits help shape the distribution of MAOM across Earth's biomes, and modulate biome‐specific responses of MAOM to climate change. We leverage a global synthesis of MAOM measurements to provide estimates of the total amount of MAOM‐C globally (~840–1540 Pg C; 34%–51% of total terrestrial organic C), and its distribution across Earth's biomes. We show that MAOM‐C concentration is highest in temperate forests and grasslands, and lowest in shrublands and savannas. Grasslands and croplands have the highest proportion of soil organic carbon (SOC) in the MAOM fraction (i.e. the MAOM‐C:SOC ratio), while boreal forests and tundra have the lowest MAOM‐C:SOC ratio. Drawing on our trait framework, we then review experimental data and posit the effects of climate change on MAOM pools in different biomes.We conclude by discussing how MAOM is integrated into soil C models, and how feedstock and MAOM formation traits may be included in these models. We also summarize the projected fate of MAOM under climate change scenarios (Representative Concentration Pathways 4.5 and 8.5) and discuss key model uncertainties.Read the free Plain Language Summary for this article on the Journal blog.