Features of the spatial Distribution of Carbon Dioxide in the Atmosphere of the Steppe Landscapes (Orenburg Region, Volga-Ural Region)

The Russian steppes play a certain role in absorbing atmospheric carbon and maintaining biospheric regulation, and therefore monitoring the climate-regulating characteristics of steppe ecosystems is relevant, including the concentration of carbon dioxide in the atmosphere. The objectives of the study are to identify the features of the atmospheric carbon dioxide spatial distribution in the Ural part of the Volga-Ural steppe region (Orenburg region) and to analyze the relationship between the carbon dioxide content in the air and meteorological characteristics. A representative network of 107 key sites has been identified for research, including the subzones of the meadow steppe, fescuefeather grass forb steppes, and poor herb fescue-feather grass steppes. During field work, measurements of atmospheric carbon dioxide concentration an altitude of 1,5–2 m, air temperature and humidity, wind speed, soil temperature and humidity were carried out at each site. The following results were obtained: carbon dioxide concentrations ranging from 0.035 to 0.065% by volume were recorded in the air mixture at the study sites. It was revealed that the index of carbon dioxide content in the studied air layer has an inverse dependence on air temperature and a direct dependence on its humidity. The formation of several territorial clusters with similar values of the desired indicator was noted in the study region. Clusters with both low and high levels of atmospheric carbon dioxide are distinguished in the zones of the fescue-feather grass forb steppes and poor herb fescue-feather grass steppes. Clusters with high values of atmospheric carbon dioxide were found in the subzones of the poor herb fescue-feather grass steppes and meadow steppe. It is assumed that the features of the spatial distribution of carbon dioxide in the air of the steppe region are mainly related to the specifics of the characteristics of steppe subzones and do not show dependence on the local landscape characteristics of key sites.