Microorganisms in the cryogenic meadow-steppe soils of Central Yakutia

Abstract

The microbial communities of cryogenic meadow-steppe soils in Central Yakutia, developed within the Yakut Botanical Garden (YBG), have not been previously investigated. This study aimed to analyze soil properties, the composition of microbial communities, their abundance, and their distribution within soil profiles. Data were collected from five soil profiles of the examined cryogenic soils using a combination of soil and microbiological methods, along with standard laboratory analytical techniques. The abundance of microorganism groups studied ranged from 8.2 ± 3.3 × 10¹ to 2.4 ± 0.8 × 10⁶ CFU/g of soil. The soils exhibited an increasing sequence of total microorganisms: saline solonetz, meadow-chernozem, ordinary chernozem, chernozem-meadow, and meadow-chernozem. The highest concentration of azotobacter was identified in the chernozem, which was the only unsalted soil among those studied. The dominance of specific microbial groups was found to be influenced by the chemical composition of the soils and their hydrothermal parameters. A strong correlation was established between the number of microorganism and the content of humus and nitrogen, as well as soil temperature, which decreased with depth. The microbiological findings of cryogenic meadow-steppe soils in the cryolithozone region can be utilized to bioindicate soil fertility and assess anthropogenic and agrogenic transformations of cryogenic soils.