Collaborative Research: Volatile organic compounds released during litter decomposition and their relevance to soil ecology

合作研究：凋落物分解过程中释放的挥发性有机化合物及其与土壤生态的相关性

• 批准号: 1556753
• 负责人: Noah Fierer
• 金额: $ 53.02万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2019-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556753&HistoricalAwards=false
• 关键词: Collaborative; Research; Volatile; organic; compounds

Walking through a forest, one can often smell the characteristic scents of decomposing vegetation - fragrances from the many natural chemicals (volatile organic compounds or VOCs) that are released as vegetation breaks down. These compounds not only give decomposing leaves their characteristic odor, they are also important to the chemistry of the atmosphere, and to underlying soils, where they can influence soil fertility and alter the types of organisms residing in soil. Hundreds of different VOCs can also be released by the microbes that consume vegetation on the forest floor, and microbial decay of leaves and branches from different plant species produces distinct VOCs during decomposition, contributing to the different smells of a pine versus an oak forest, for example. Scientists do not yet understand how the types and amounts of these substances vary as plant matter decomposes. Researchers also need to understand how the release of VOCs will be altered as forest composition shifts seasonally with changes in the environment. This research will not only address these knowledge gaps, it will also determine the importance of VOCs to underlying soils; how they may promote the storage of carbon in forest soils, and how they can influence soil fertility by altering nitrogen cycling and the types of microorganisms found in soils. This project will be conducted by a team of researchers both at the University of Colorado and at Virginia Tech where the project will train undergraduate and graduate students in cutting-edge research. In addition, researchers at these universities will use the research results to introduce high school students to key concepts and tools in the study of soils and their roles in sustaining ecosystems.All decomposing plant litter emits VOCs, and the total amount of carbon (C) released as VOCs can be surprisingly high, with some litters emitting VOCs at rates approaching that of C emissions as carbon dioxide. The proposed research will use a series of field and laboratory-based studies to determine 1) how the amounts and types of VOCs emitted vary as litter decomposition progresses, 2) the sensitivity of these emissions to changes in moisture and temperature regimes, 3) the degree to which the VOCs produced during litter decomposition represent a source of organic C to underlying soils, and 4) how these VOCs impact microbial communities and key nitrogen cycling processes in soil. Together, the proposed work will improve model representations of VOC fluxes from terrestrial ecosystems, an important objective given that some of these litter-derived VOCs can promote the formation of ozone and secondary organic aerosols in the atmosphere. In addition, this research will explore an understudied mechanism by which leaf litter can influence the biotic and abiotic characteristics of underlying soils. Ultimately this research could lead to the development of novel strategies to manage soil by identifying specific VOCs that could reduce soil pathogen loads or alter the rates of specific microbial processes that are critical to the maintenance of soil fertility.

走在森林里，人们经常能闻到植物分解的特有气味——植物分解时释放出的许多天然化学物质（挥发性有机化合物或VOCs）的香味。这些化合物不仅使正在分解的叶子散发出特有的气味，而且对大气和下层土壤的化学成分也很重要，因为它们可以影响土壤的肥力，改变土壤中生物的类型。消耗森林地面植被的微生物也会释放出数百种不同的挥发性有机化合物，不同植物物种的叶子和树枝的微生物腐烂在分解过程中会产生不同的挥发性有机化合物，例如，松树林和橡树林的气味不同。科学家们还不知道这些物质的种类和数量在植物分解过程中是如何变化的。研究人员还需要了解，随着森林成分随环境的季节性变化而变化，挥发性有机化合物的释放将如何改变。这项研究不仅将解决这些知识空白，还将确定voc对底层土壤的重要性；它们如何促进森林土壤中的碳储存，以及它们如何通过改变氮循环和土壤中发现的微生物类型来影响土壤肥力。该项目将由科罗拉多大学和弗吉尼亚理工大学的一组研究人员进行，该项目将培养本科生和研究生进行尖端研究。此外，这些大学的研究人员将利用研究成果向高中生介绍土壤及其在维持生态系统中的作用研究中的关键概念和工具。所有分解的植物凋落物都会释放挥发性有机化合物，而以挥发性有机化合物形式释放的碳(C)总量可能会惊人地高，有些凋落物释放挥发性有机化合物的速度接近以二氧化碳形式释放的碳的速度。拟议的研究将使用一系列基于现场和实验室的研究来确定1)随着凋落物分解的进展，挥发性有机化合物排放的数量和类型如何变化；2)这些排放对湿度和温度变化的敏感性；3)凋落物分解过程中产生的挥发性有机化合物在多大程度上代表了下层土壤有机碳的来源；4)这些挥发性有机化合物如何影响土壤中的微生物群落和关键的氮循环过程。总之，拟议的工作将改进陆地生态系统挥发性有机化合物通量的模型表示，这是一个重要的目标，因为其中一些来自凋落物的挥发性有机化合物可以促进大气中臭氧和二次有机气溶胶的形成。此外，本研究还将探讨凋落叶影响下垫土壤生物和非生物特性的机制。最终，这项研究可以通过识别特定的挥发性有机化合物来开发新的土壤管理策略，这些挥发性有机化合物可以减少土壤病原体负荷或改变对维持土壤肥力至关重要的特定微生物过程的速率。