Carbon Dioxide in Soil and Surface Waters in the North of Western Siberia: Methodological Approach and Quantitative Characteristics

Abstract

Dissolved inorganic carbon is an essential component of the carbon cycle, especially in the northern regions; however, its loss through water bodies is still rarely included in regional carbon models. The tasks of the work comprise a detailed coverage of the methodological approach of “headspace equilibration” for assessing the concentration of dissolved CO₂ in soil and surface waters and estimation of the CO₂ concentration range in waters of different geneses in the landscapes of northern Western Siberia. The performed methodological work has allowed a headspace equilibration protocol for measuring the CO₂ concentration in waters to be elaborated and described with detailed calculations. The CO₂ concentration in soil (suprapermafrost) and surface waters (river, bog, lake, etc.) ranges from 13 to 2983 µmol/L (274 to 57 000 µatm), and the vast majority of objects are supersaturated with CO₂ relative to the atmosphere. The maximum concentrations are characteristic of suprapermafrost soil and bog waters, and the minimum concentrations are in the waters of aquatic ecosystems (thermokarst and forest lakes). A high variability of CO₂ concentrations in waters necessitates a large number of measurements to provide adequate estimates.