October 16-17, 2018 | Lincoln, Nebraska
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2018 NRIC speakers
portrait of Kelly Wrighton


Kelly Wrighton
Colorado State University

Methanogenesis in soils: It may not be as deep as we all thought

The current paradigm, widely incorporated in soil biogeochemical models, is that microbial methanogenesis can only occur in anoxic habitats. In contrast, here we use porewater and greenhouse-gas flux measurements to show clear evidence for methane production in well-oxygenated wetland soils. A comparison of oxic to anoxic soils revealed up to ten times greater methane production and nine times more methanogenesis activity in oxygenated soils. Metagenomic and metatranscriptomic sequencing recovered the first near complete genomes for a novel methanogen species, and showed acetoclastic production from this organism was the dominant methanogenesis pathway in oxygenated soils. This organism, Candidatus Methanosaeta oxydurans, is prevalent across methane emitting ecosystems, suggesting a global significance. Moreover, in this wetland, we estimated that a dominant fraction of methane fluxes could be attributed to methanogenesis in oxygenated soils. Together our genomic enabled findings challenge a widely-held assumption about methanogenesis, with significant ramifications for global methane estimates and Earth system modeling.
Kelly Wrighton is an Assistant Professor of Soil and Crop Science at Colorado State University. Her laboratory uses multi-omic data coupled with anaerobic physiological methods to interrogate microbial metabolic interactions in soils, subsurface, and gut ecosystems.