EAGER: Are methylotrophic substrates important in northern peatland methane cycling?

EAGER：甲基营养底物在北部泥炭地甲烷循环中重要吗？

• 批准号: 1645360
• 负责人: Cassandra Zalman
• 金额: $ 19.55万
• 依托单位: Chapman University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1645360&HistoricalAwards=false
• 关键词: EAGER; methylotrophic; substrates; important; northern

Peatlands are a type of wetlands common in many northern landscapes. These ecosystems play an important role in the global carbon cycle. As a result of natural decomposition processes, peatlands contribute a significant fraction of methane gas to the atmosphere and could release additional methane in response to changes in environmental conditions. Our current understanding of peatland methane dynamics is built upon the premise that methane is produced through two different microbial processes in natural ecosystems. However, there is evidence that a third pathway of methane production has been overlooked, and could be important. Using a combination of field measurements and laboratory experiments, the research team will investigate the potential role of methane produced through the previously unexplored pathway in peatlands in Minnesota. This research will also provide opportunities to train undergraduate students how to do research at Chapman University, a primarily undergraduate institution.The central goal of this EAGER project is to explore the possibility that methylotrophic substrates (e.g., methanol, monomethylamine and dimethylsulfide) serve as important sources of methane in northern peatland ecosystems. This project will address 4 research questions in 3 peatlands in northern Minnesota. (1) Can methylotrophic substrates be processed by methanogens? To investigate the potential for methane production through methylotrophic pathways, the researchers will use 13C-labeled substrates as isotopic tracers in laboratory incubations. (2) Are methylotrophic substrates available in situ? The researchers will develop analytical techniques to measure concentrations of methylotrophic substrates in peatland porewater. (3) What are the rates of methylotrophic methanogenesis over a growing season? The researchers will combine measurements of methane production from 13C-labeled tracers and concentrations of methylotrophic substrates to estimate rates of methylotrophic methanogenesis across the growing season in the second year of this project. (4) What microbial communities are responsible for methylotrophic methanogenesis? The researchers will analyze the microbial communities potentially responsible for methylotrophic methane production. Given the importance of peatlands in the global carbon cycle, it is crucial to have a complete mechanistic understanding of methane cycling in these habitats. If previously understudied methylotrophic substrates are important in peatland methane cycling, it would require reconsideration of carbon cycle models at local to global scales.

泥炭地是北方许多景观中常见的一种湿地。这些生态系统在全球碳循环中发挥着重要作用。由于自然分解过程，泥炭地向大气中贡献了很大一部分甲烷气体，并可能因环境条件的变化而释放额外的甲烷。我们目前对泥炭地甲烷动态的理解是建立在这样的前提之上的：甲烷是通过自然生态系统中两种不同的微生物过程产生的。然而，有证据表明，甲烷生产的第三种途径被忽视了，而且可能很重要。利用现场测量和实验室实验的结合，研究小组将调查通过明尼苏达州泥炭地以前未探索的途径产生的甲烷的潜在作用。这项研究还将提供机会，培训本科生如何在查普曼大学，一个主要的本科机构做研究。这个EAGER项目的中心目标是探索甲基营养基质（例如，甲醇、一甲胺和二甲硫醚）是北方泥炭地生态系统中甲烷的重要来源。本计画将针对明尼苏达州北方三个泥炭地的四个研究问题。(1)甲烷菌能处理甲基营养基质吗？为了研究通过甲基营养途径产生甲烷的潜力，研究人员将在实验室孵育中使用13C标记的底物作为同位素示踪剂。(2)甲基营养基质是否可在原位获得？研究人员将开发分析技术来测量泥炭地孔隙水中甲基营养基质的浓度。(3)在一个生长季节中，甲基营养型甲烷生成的速率是多少？研究人员将结合联合收割机测量甲烷生产从13 C标记的示踪剂和浓度的甲基营养基质，以估计整个生长季节的甲基营养产甲烷率在该项目的第二年。(4)什么样的微生物群落负责甲基营养型甲烷生成？研究人员将分析可能导致甲基营养型甲烷产生的微生物群落。鉴于泥炭地在全球碳循环中的重要性，对这些栖息地中的甲烷循环有一个完整的机械理解是至关重要的。如果以前未充分研究的甲基营养基质是重要的泥炭地甲烷循环，这将需要重新考虑碳循环模型在本地到全球范围内。