CO₂ leakage alters bacterial community structure and metabolic function of soybean rhizosphere in the Ordos Basin

CO₂ capture and storage (CCS) is a pivotal technology for mitigating global climate change, but CO₂ leakage from geological storage sites risks disrupting soil rhizosphere bacterial communities critical to soil functionality. To clarify their response mechanisms, this study focused on CO₂-sensitive soybean (Shanning 17) in the Ordos Basin, establishing a simulated CO₂ leakage platform with four treatments: CK (control, ambient CO₂), 10%, 30%, and 50%. Illumina NovaSeq 16 S rRNA sequencing combined with PICRUSt functional prediction was used to analyze rhizosphere bacteria. Results showed CO₂ leakage altered the bacterial community: Chao1 index decreased by up to 4.27%, Pielou's evenness index increased, and Beta diversity changed notably. Bacteroidetes relative abundance increased significantly, while Proteobacteria, Acidobacteria, and Nitrospirae decreased; the rare phylum Deferribacteres was only detected under 30% and 50% CO₂; Five key genera (RB41, MND1, Nitrospira, Solirubrobacter, Gaiella) dominated community shifts, with abundance trends matching their phyla. Functionally, The dominant Level 1 metabolism pathway (average relative abundance 81.02%), as well as the Level 2 pathways of amino acid metabolism, carbohydrate metabolism, and energy metabolism, were significantly affected, and these functional changes were closely linked to shifts in bacterial community structure. This study supports environmental impact and risk assessment for CCS projects in the Ordos Basin and similar geological storage areas.