Метан и сероводород в донных отложениях лиманов Азово-Черноморского бассейна

Abstract

In the summer-autumn period of 2013–2018, studies were conducted on the distribution of methane (CH4) and hydrogen sulfide (ΣH2S) in the estuaries of the Azov (Yeisky, Beisugsky, Sladky, Kurchansky and Akhtanizovsky) and Black (Vityazevsky, Kiziltashsky and Bugazsky) seas characterized by different salinity. For the first time, to characterize the conjugate distribution of CH4 and ΣH2S in the bottom sediments of aquatic ecosystems, the "methanization" coefficient was used, which is the percentage of CH4 from the sum of concentrations (in mg/g) of reduced gases – ΣH2S and CH4. Concentrations of CH4 and ΣH2S in bottom sediments of desalinated estuaries with water salinity from 0,26 to 8,20% (Sladky, Akhtanizovsky and Kurchansky) vary from 0,01 to 114,34 μg/g of wet sediment and from <0,001 to 3,07 mg/g of wet sediment, respectively. Concentrations of CH4 and ΣH2S in sediments of saline estuaries with water salinity from 10,7 to 58% (Yeisky, Beisugsky, Vityazevsky, Kiziltashsky and Bugazsky) vary from 0,01 to 1,44 micrograms/g and from 0,01 to 1,44 μg/g, respectively. The methanization coefficient in sediments of saline estuaries varies in the range from 0,002 to 1,38% and in 97% of the samples taken does not exceed 1%, which indicates a significant dominance of the sulfide formation process over the methanogenesis process. In the sediments of desalinated estuaries, the methanization coefficient increases markedly (up to 19,14%), while the proportion of sediments with a percentage of CH4 of more than 1% increases to 32%. The closeness of correlations between the studied reduced gases and hydrochemical parameters is analyzed.