DNA Metabarcoding of Soil Microbial Communities in a Postvolcanic Region: Case Study from Băile Lăzărești, Romania

Those data investigates the impact of post-volcanic gas emissions on soil microbial communities in the Băile Lăzărești region (Romania). Nineteen soil samples across a CO2 gradient ranging from background levels to ≈46,221 ppm. Methane and hydrogen sulfide showed localized peaks (CH4 up to 8271 ppm; H2S up to ~10.12 ppm), with CH4 contributing to outlier community patterns. eDNA metabarcoding identified 3064 OTUs, (2463 bacterial and 601 fungal). Bacteria were dominated by Proteobacteria, fungi by Ascomycota, with Thelebolales nearly ubiquitous. Alpha diversity (Chao1, Fisher) declined significantly in high-CO2 soils (>3000 ppm), while intermediate concentrations (1000–3000 ppm) showed heterogeneous responses. Beta-diversity analyses (PCoA, clustering) revealed distinct grouping of high-CO2 soils, with sample P16 (CH4-rich) forming an outlier. A PCA including CO2, CH4, and H2S confirmed CO2 as the main driver of variance (>65%), with CH4 accounting for local effects. At the genus level, Acidobacterium, Granulicella, Streptomyces, and Nocardia increased with CO2, while Rhizobium and Pseudomonas declined. Fungal responses were mixed: Thelebolus and Cladosporium increased, whereas Mortierella and Cryptococcus decreased. Overall, elevated soil CO2 reduced microbial richness and reorganized communities, while CH4 shaped local niches. These findings provide key natural analog insights for assessing ecological risks of CO2 leakage from geological storage.本数据集旨在探究罗马尼亚巴莱拉泽雷什蒂（Băile Lăzărești）地区火山喷发后气体排放对土壤微生物群落的影响。研究沿CO₂浓度梯度采集了19份土壤样品，梯度范围覆盖本底水平至约46221 ppm。甲烷（CH₄）与硫化氢（H₂S）存在局部峰值，其中甲烷最高达8271 ppm，硫化氢最高约10.12 ppm，甲烷是造成群落异常分布模式的关键因素。通过环境DNA（eDNA）宏条形码分析，共鉴定出3064个操作分类单元（Operational Taxonomic Unit，OTU），其中细菌2463个、真菌601个。细菌群落以变形菌门（Proteobacteria）为主，真菌群落则以子囊菌门（Ascomycota）占优，柔膜菌目（Thelebolales）几乎遍布所有样品。α多样性（Chao1指数、Fisher指数）在高CO₂土壤（>3000 ppm）中显著下降，而中等浓度CO₂（1000~3000 ppm）组则呈现异质性响应。β多样性分析（主坐标分析PCoA、聚类分析）结果显示，高CO₂土壤样品形成了独特的聚类簇，其中样品P16（富甲烷）呈现异常分离。纳入CO₂、甲烷与硫化氢的主成分分析（PCA）证实，CO₂是群落变异的主要驱动因子（变异解释度>65%），甲烷则对局部群落特征产生影响。在属水平上，酸杆菌属（Acidobacterium）、芽生球菌属（Granulicella）、链霉菌属（Streptomyces）与诺卡氏菌属（Nocardia）的相对丰度随CO₂浓度升高而增加，而根瘤菌属（Rhizobium）与假单胞菌属（Pseudomonas）则呈下降趋势。真菌群落的响应则较为复杂：掷囊菌属（Thelebolus）与枝孢霉属（Cladosporium）丰度上升，而被孢霉属（Mortierella）与隐球菌属（Cryptococcus）丰度下降。总体而言，土壤中CO₂浓度升高会降低微生物群落丰富度并重塑群落结构，而甲烷则塑造了局部生态位。本研究结果可为评估地质封存CO₂泄漏的生态风险提供关键的自然类比依据。