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

Chapman University, Orange CA

Investigators

Abstract

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.