Relationships between radiation, wildfire and the soil microbial communities in the Chornobyl Exclusion Zone

• Published in: The Science of the total environment 2024-11, Vol.950, p.175381, Article 175381
• Main Authors: de Menezes, Alexandre Barretto, Gashchak, Sergii, Wood, Michael D., Beresford, Nicholas A.
• Format: Article
• Language: English
• Subjects: Chernobyl; Ecological recovery; Environmental stress; Radioactivity; Radioecology; Soil microbial ecology
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.175381

There is considerable uncertainty regarding radiation's effects on biodiversity in natural complex ecosystems typically subjected to multiple environmental disturbances and stresses. In this study we characterised the relationships between soil microbial communities and estimated total absorbed dose rates to bacteria, grassy vegetation and trees in the Red Forest region of the Chornobyl Exclusion Zone. Samples were taken from sites of contrasting ecological histories and along burn and no burn areas following a wildfire. Estimated total absorbed dose rates to bacteria reached levels one order of magnitude higher than those known to affect bacteria in laboratory studies. Sites with harsher ecological conditions, notably acidic pH and low soil moisture, tended to have higher radiation contamination levels. No relationship between the effects of fire and radiation were observed. Microbial groups that correlated with high radiation sites were mostly classified to taxa associated with high environmental stress habitats or stress resistance traits. Distance-based linear models and co-occurrence analysis revealed that the effects of radiation on the soil microbiome were minimal. Hence, the association between high radiation sites and specific microbial groups is more likely a result of the harsher ecological conditions in these sites, rather than due to radiation itself. In this study, we provide a starting point for understanding the relationship between soil microbial communities and estimated total absorbed radiation dose rates to different components of an ecosystem highly contaminated with radiation. Our results suggest that soil microbiomes adapted to natural soil conditions are more likely to be resistant to ionising radiation than expected from laboratory studies, which demonstrates the importance of assessing the impact of ionising radiation on soil microbial communities under field conditions. [Display omitted] •The impact of radiation contamination in complex ecosystems is poorly understood.•The soil microbiome in Chornobyl's Red Forest region was sequenced.•Effect of radiation compared to soil properties, wildfire, and site properties•Radiation had a minor effect on the soil microbiome.•Red Forest soil microbiome appears adapted/resistant to current radiation levels.