DISSERTATION RESEARCH: Microbial Oxidation of Methane in Anaerobic Soils: Ecological Significance in Mitigating Terrestrial Methane Flux

消耗甲烷的微生物可以在控制全球气候方面发挥重要作用，因为在温室效应中，每个甲烷分子的效率大约是二氧化碳的26倍。尽管许多研究对土壤甲烷消耗进行了调查，但它们侧重于氧气存在时的甲烷消耗，而忽视了无氧甲烷消耗(甲烷无氧氧化；AOM)的潜在重要作用。潮湿的热带森林是全球重要的大气甲烷来源，占所有甲烷排放的17%以上。北方和北极的湿润土壤也向大气中释放了大量甲烷，产生了超过10%的甲烷排放。重要的是确定和描述有助于控制来自这些生物群的甲烷通量的过程和生物体。甲烷的厌氧氧化是一个潜在的重要过程，以前在热带或北方陆地系统中没有发现。初步工作表明，AOM确实存在于热带和北方土壤中。本论文研究了波多黎各卢基洛实验森林和阿拉斯加Bonanza Creek LTER作为热带和北方模式生态系统的土壤中的土壤有机质。微花岗岩及其甲烷氧化活性将使用分子和基因组技术结合地球化学分析进行分析。这项研究将促进我们对厌氧甲烷氧化的微生物基础和分布的理解，并确定这一土壤过程是否在气候强迫中起重要作用。这些知识将帮助我们了解土地利用变化对土壤甲烷消耗的可能影响。为了帮助年轻科学家了解生态学研究，本科生将通过加州大学伯克利分校自然资源学院赞助的SPUR(本科生研究赞助项目)项目参与该项目。该项目完成后，成果将在同行评议的国际期刊上发表，并在国际科学会议上公布。

Microorganisms that consume methane can play an important role in controlling global climate since each molecule of methane is about 26 times more effective than carbon dioxide in the greenhouse effect. Although many studies have investigated soil methane consumption, they have focused on methane consumption in the presence of oxygen, overlooking the potentially important role of anaerobic methane consumption (anaerobic oxidation of methane; AOM). Humid tropical forests are globally significant sources of atmospheric methane, accounting for more than 17% of all methane emissions. Boreal and arctic wet soils also release significant quantities of methane to the atmosphere, producing over 10% of all methane emissions. It is important to identify and characterize processes and organisms that help to control methane fluxes from these biomes. Anaerobic oxidation of methane is a potentially important process not previously identified in tropical or boreal terrestrial systems. Preliminary work demonstrates that AOM does occur in both tropical and boreal soils. This dissertation project investigates AOM in soils from Luquillo Experimental Forest (Puerto Rico) and Bonanza Creek LTER (Alaska) as tropical and boreal model ecosystems. Microogranisms and their methane oxidizing activities will be analyzed using molecular and genomic techniques in combination with geochemical analyses. The proposed research will advance our understanding of the microbial basis and distribution of anaerobic methane oxidation, and determine whether this soil process important in climate forcing. This knowledge will help us understand the possible impacts of land use change on the consumption of methane by soils. To help introduce young scientists to ecological research, undergraduate students will be involved in the project through the SPUR (Sponsored Projects for Undergraduate Research) program sponsored by the College of Natural Resources at UC Berkeley. Upon completion of this project, results will be published in peer-reviewed international journals and presented at international scientific conferences.