Methane oxidation and methylotroph population dynamics in groundwater mesocosms

Olukayode Kuloyo, S. Emil Ruff, Aaron Cahill, Liam Connors, Jackie K. Zorz, Isabella Hrabe de Angelis, Michael Nightingale, Bernhard Mayer, Marc Strous

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)
29 Downloads (Pure)


Extraction of natural gas from unconventional hydrocarbon reservoirs by hydraulic fracturing raises concerns about methane migration into groundwater. Microbial methane oxidation can be a significant methane sink. Here, we inoculated replicated, sand-packed, continuous mesocosms with groundwater from a field methane release experiment. The mesocosms experienced thirty-five weeks of dynamic methane, oxygen and nitrate concentrations. We determined concentrations and stable isotope signatures of methane, carbon dioxide and nitrate and monitored microbial community composition of suspended and attached biomass. Methane oxidation was strictly dependent on oxygen availability and led to enrichment of 13C in residual methane. Nitrate did not enhance methane oxidation under oxygen limitation. Methylotrophs persisted for weeks in the absence of methane, making them a powerful marker for active as well as past methane leaks. Thirty-nine distinct populations of methylotrophic bacteria were observed. Methylotrophs mainly occurred attached to sediment particles. Abundances of methanotrophs and other methylotrophs were roughly similar across all samples, pointing at transfer of metabolites from the former to the latter. Two populations of Gracilibacteria (Candidate Phyla Radiation) displayed successive blooms, potentially triggered by a period of methane famine. This study will guide interpretation of future field studies and provides increased understanding of methylotroph ecophysiology.

Original languageEnglish
Pages (from-to)1222-1237
Number of pages16
JournalEnvironmental Microbiology
Issue number4
Early online date3 Feb 2020
Publication statusPublished - 1 Apr 2020

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics


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