Carbon isotope composition of methane emissions in the Czech Republic - preliminary results

 

Authors: Buzek F, Holub V, Boháček Z, Franců J

Published in: Bulletin of Geosciences, volume 74, issue 2; pages: 191 - 196;

Keywords: methane, emissions, peat bogs, brown coal, bitumenous coal, carbon isotopic composition, microbial oxidation,

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Abstract

To specify the sources of atmospheric methane emissions in the Czech Republic, the carbon isotope composition of most anthropogenic sources was measured. Study includes pipeline gas (PG), gas emissions from peat bog (PB), emissions related to brown coal mining in the North Bohemian Brown Coal Basin (NBBCB) and of bituminous coals from Carboniferous of Central Bohemia (CB) and Upper Silesian Coal Basin (USCB).
The delta;13C values vary from -20 ‰ (CB) to -75 ‰ (biogenic gas USCB). Methane samples from PB, NBBCB and USCB were affected by microbial oxidation which changes both methane concentration and its isotopic composition. Oxidation lowers the net methane flux into the atmosphere. The most important anthropogenic source (USCB) has been studied in detail. Two types of methane dominate in this area: a thermogenic gas with the delta;13C value close to -40 ‰ and a biogenic gas with the delta;13C values in range from -55 to -75 ‰ . Biogenic methane in aerated mine zones has been reoxidized back to carbon dioxide with the delta;13C values in range from -30 to -50 ‰ .