Peculiarities of CH4 and CO2 Distribution in Sediments of the Arctic Seas

• Published in: Geochemistry international 2023-02, Vol.61 (2), p.150-159
• Main Authors: Sevastyanov, V. S., Fedulova, V. Yu, Kuznetsova, O. V., Naimushin, S. G., Dushenko, N. V., Fedulov, V. S., Krivenko, A. P., Malova, A. I., Tkachenko, E. A.
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Carbon dioxide concentration; Coefficients; Cores; Correlation coefficient; Correlation coefficients; Deep layer; Dimethyl sulfide; Distribution; Earth and Environmental Science; Earth Sciences; Gas formation; Gases; Geochemistry; Marine sediments; Methane; Methanogenesis; Sediment; Sediments; Sulfate reduction; Sulphate reduction; Sulphides
• ISSN: 0016-7029; 1556-1968
• DOI: 10.1134/S0016702923020088

The distribution of the concentrations of CH 4 and CO 2 and other gases in the sediments of the Kara, Laptev and East Siberian seas was studied. A correlation was found between CH 4 and CO 2 in most sediment cores. The correlation coefficient R for the sediments of the Kara Sea ranges from 0.58 to 0.97 and does not depend on the gas distribution with depth. Methanogenesis in marine sediments is presumably associated with sulfate reduction, and hydrogenotrophic methanogenesis leads to an increase in CH 4 concentration against the background of high CO 2 concentration. The high concentration of dimethyl sulfide in the sediments indicates the simultaneous formation of CH 4 and CO 2 through methylotrophic methanogenesis with the participation of CH 3 SCH 3 . In the upper layers of the sediment, opposite trends in the CH 4 and CO 2 distribution can be observed. The fact that the correlation coefficients between CH 4 and CO 2 gases in the sediments of the Laptev Sea acquire both negative and positive values is probably related to the fact that gas formation processes in the upper layers of the sediment captured by short columns differ from those of deep layers.