Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Hodgkins, Suzanne B., Tfaily, Malak M., McCalley, Carmody K., Logan, Tyler A., Crill, Patrick M., Saleska, Scott R., Rich, Virginia I., Chanton, Jeffrey P.
• Format: Text
• Language: English
• Published: National Academy of Sciences 2014
• Subjects: Physical Sciences; permafrost
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000816; http://www.ncbi.nlm.nih.gov/pubmed/24711402; https://doi.org/10.1073/pnas.1314641111

We address the effect of thawing permafrost, and attendant subsidence-induced shifts in hydrology and plant community structure, on CH4 and CO2 production potentials and mechanisms driven by changes in organic matter chemical composition in a thawing peatland complex. Advanced analytical characterization of peat and dissolved organic matter along the thaw progression indicated increasingly reduced organic matter experiencing greater humification rates, which were associated with higher relative CH4 and CO2 production potentials, increasing relative CH4/CO2 production ratios, and shifts from hydrogenotrophic to acetoclastic methanogenesis. The effects of this increase in organic matter reactivity with permafrost thaw could intensify the increases in CH4 and CO2 release already predicted due to increasing temperatures, permafrost carbon mobilization, and waterlogging-induced changes in redox conditions.