Potential for Aerobic Methane Oxidation in Carboniferous Coal Measures

Abstract

Carbon (C), geologically sequestered in coal, is gradually released to the atmosphere as CH₄ and CO₂. Recent anthropogenic activity (coal mining) has rapidly increased the rate of C reallocation from coal deposits into the atmosphere, which has deleterious effect on the climate as both gases are effective infrared absorbers. In the current study we demonstrate that the coal bearing sedimentary rocks possess potential of biological methane oxidation. Viable methanotrophic bacteria, capable of methane oxidation at ambient air and a range of methane concentrations were found in coalbearing formations of the Upper Silesian (USCB) and Lublin Coal Basins (LCB). Factors controlling activity of the aerobic methanotrophic bacteria in the deep subsurface such as, depth, methane concentration, available electron acceptors, moisture and nutrients availability were investigated along with paleoenvironmental factors (temperature changes during and after burial and paleohydrological infiltration). The distribution and activity of the methanotrophic bacteria in the deep subsurface were found to be influenced by geological conditions among which evolution of paleotemperatures and paleohydrological conditions play a predominant role. The data presented along with analysis of molecular composition of the coalbed gases in various coal basins worldwide has led to the conclusion that aerobic methanotrophy may be a widespread process, which, to our knowledge, so far has not been included in investigations concerning C cycling in the subsurface.

Keywords:

• coal
• coal mining
• methane oxidation
• methanotrophic activity
• methanotrophic bacteria
• paleoenvironmental conditions

Acknowledgments

The authors acknowledge Lubelski Węgiel Bogdanka SA and Jastrzębska Spółka Węglowa SA for allowing access to coalbed rock samples and providing information about geological settings of the sampled area.

Additional information

Funding

This work was supported by research grants (N N305 111336 and N N305 326939) founded by Polish Ministry of Science and Higher Education and National Science Center.