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Carbon (C), geologically sequestered in coal, is gradually released to the atmosphere as CH4and 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. [ABSTRACT FROM AUTHOR]

Methanotrophic bacteria (MB) are an important group of microorganisms, involved in the greenhouse gas (GHG) cycles. They are responsible for the utilization of methane, one of the main GHGs, which is released in large amounts (via biogenic and abiogenic processes) during coal formation. This study aimed to determine the main factors affecting the distribution of the MB in two lignite-bearing series of the Turów and Bełchatów coal basins. Distribution of MB in the lignite profiles was studied using methanotroph-specific lipid biomarkers such as amino-bacteriohopanepolyols (NH-BHPs) and C-3 methylated BHPs. BHP results were combined with physical and chemical properties of the studied sediments. In general, lignites were richer in BHPs than the mineral samples, which points to the important role of the intrinsic methane cycling. NH-BHP speciation confirmed that the methanotrophic community of the studied sediments was a combination of both type I and, especially, type II methanotrophs. Based on geological data, it was suggested that elevated temperature during diagenesis intensifies decomposition of methanotroph-specific biomarkers (aminopentol and 3-Me BHT). It was found that the tested BHPs can derive from both fossil and living MB. The presence of metabolically active methanotrophs should therefore be accounted for during studies aimed at using lignite deposits as a source of methane. [ABSTRACT FROM AUTHOR]