Features of the coupled distribution of methane and hydrogen sulfide in the bottom sediments of the Azov and Black Seas firth

Abstract

In the summer-autumn period, studies of the conjugate distribution of methane and total hydrogen sulfide in the bottom sediments of the limans of the Azov and Black Seas, characterized by different salinity, were carried out. For the first time, to characterize the conjugate distribution of CH4 and ΣH2S in bottom sediments, the “methanization” coefficient was used, which is the percentage of CH4 from the summa of concentrations (mg/g) of CH4 and ΣH2S. The concentrations of CH4 and ΣH2S in bottom sediments of desalinated limans (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. The concentrations of CH4 and ΣH2S in the sediments of saline limans (Yeisky, Beisugskysky, Vityazevsky, Kiziltashsky, and Bugazsky) vary from 0.01 to 1.44 μg/g and from 0.01 to 1.44 mg/g, respectively. The coefficient of methanization in the bottom sediments of saline limans varies from 0.002 to 1.38% and does not exceed 1% in 97% of the samples taken. In the deposits of desalinated limans, the methanization coefficient noticeably increases (up to 19.14%). The tightness of the correlation between the studied reduced gases and hydrochemical parameters is analyzed.