DISSERTATION RESEARCH: Quantification and Characterization of the Production of Methane in Living Trees

论文研究：活树中甲烷产生的量化和表征

• 批准号: 1405135
• 负责人: Mark Bradford
• 金额: $ 2.16万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1405135&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Quantification; Characterization; Production

Previous studies into the production of methane in living trees suggest that trees have the potential to be a globally significant source of methane, which is an important greenhouse gas. Wood-rot inside living trees is known to be common, but the production of methane from this rotting material has not been considered in global methane budgets. Using a collaborative kit-based sampling effort, gas will be collected from living trees, dead wood, and debris, in western conifer forests and results evaluated in the context of forest management approaches that maximize carbon storage and hence limit methane production. A great deal of attention has been focused on forests and their role in mitigating the potentially catastrophic impacts of global change on the health of millions of people worldwide. For forest management to be as effective as possible at carbon capture, it is imperative that a better understanding of the fundamental dynamics of forest-climate interactions is developed. The quantification and characterization of methane emission from upland forests that will be undertaken in this project can inform climate modelers and forest managers about the potential role of tree-methane emission in carbon cycling. Beyond generating needed data, the work will fund both graduate and undergraduate research experiences. Specifically, the funds will extend the dissertation of a 4th year doctoral student and be used to facilitate undergraduate research experiences with a four-year college of higher education.In upland, hardwood-dominated, eastern US forests, the occurrence of distinct species-level patterns in methane production potential suggests that the highest methane production rates drive substantial through-bark emission to the atmosphere. Initial flux estimates suggest that the magnitude of this methane source could be on the same order as the upland forest, soil methane sink. The extent to which this applies to forests more broadly is not known, as the physiology of tree species in eastern hardwood forests in the US may be particularly conducive to the development of substantive wood rot inside living trees. The physiology of coniferous species, however, can limit the spread of rot within living trees and so their potential to produce methane through this rot pathway could be much lower. Based on the methods used to measure methane production in eastern hardwood trees, the investigators will conduct paired field and laboratory studies in western US coniferous forests. Specifically, using a distributed, collaborative, kit-based sampling effort, gas will be collected from living trees, dead wood, and debris, in western conifer forests. In addition, wood samples will be collected across a chronosequence and placed in static chambers to assess the magnitude of methane flux. A subset of these debris samples will be subjected to microbial community analysis to relate observed methane flux rates and internal methane concentrations to microbial dynamics in living trees and downed dead wood.

先前对活树中甲烷生产的研究表明，树木有可能成为全球重要的甲烷来源，这是重要的温室气体。众所周知，活树中的木 - rot很常见，但是在全球甲烷预算中尚未考虑这种腐烂材料的甲烷。使用基于协作的套件的采样工作，将从西部针叶树林中从活树，死木和碎片中收集气体，并在森林管理方法中评估的结果，从而最大程度地提高碳存储，从而限制甲烷的产量。广泛关注的是森林及其在减轻全球变化对全球数百万人健康的潜在灾难性影响中的作用。为了使森林管理在碳捕获中尽可能有效，必须更好地了解森林气候相互作用的基本动态。该项目将在该项目中进行的甲烷排放的量化和表征可以为气候建模者和森林经理提供有关树甲烷排放在碳循环中的潜在作用的信息。除了生成所需的数据外，这项工作还将为研究生和本科研究经验提供资金。具体而言，这些资金将扩大对四年级的博士生的论文，并用于促进四年制高等教育学院的本科研究经验。在高地，由硬木主导的美国森林中，美国东部的美国森林，甲烷生产潜力中最高的甲烷生产率在甲烷生产的潜力中发生了不同的物种水平模式，这表明甲烷的生产率最高，使实质性通过了基本的生产率。最初的通量估计表明，该甲烷源的大小可能与高地森林，土壤甲烷下水道相同。不知道它在森林中的程度不足，因为美国东部硬木森林中树种的生理可能特别有利于开发生物内部的实质性木质腐烂。但是，针叶性物种的生理学可以限制腐烂在活树中的扩散，因此它们通过此腐烂途径产生甲烷的潜力可能要低得多。根据用于测量东部硬木树中甲烷生产的方法，研究人员将在美国西部针叶林进行配对的田间和实验室研究。具体而言，使用分布式的，基于套件的采样工作，将从西部针叶林森林中从活树，死木和碎片中收集天然气。此外，将在沿射频序列上收集木材样品，并将其放置在静态室中，以评估甲烷通量的大小。这些碎屑样品的一个子集将进行微生物群落分析，以将观察到的甲烷通量速率和内部甲烷浓度与活树和倒下的死木中的微生物动力学联系起来。