Microbial Community Dynamics in Sterilized Soils

Soils subject to sterilization present a unique environment for understanding microbial colonisation and metabolic activity in the absence of indigenous living populations. Sterilisation methods such as gamma irradiation, autoclaving and chemical treatment are routinely applied to distinguish biotic processes from abiotic reactions in experimental settings. Following sterilisation, soils undergo physicochemical alterations that influence recolonisation by microorganisms, including residual enzyme activity, nutrient release and shifts in trace‐metal availability. Studies have revealed that extracellular enzymes stabilised on soil particles can drive oxidative metabolism independent of viable cells, with important implications for carbon cycling. When sterilised soils are reintroduced to natural environments or amended with nutrients, resident or introduced microbiota re‐establish community structure through successional dynamics governed by competition, dispersal and functional gene diversity. These processes shape soil respiration, nutrient turnover and the resilience of microbial assemblages under stressors such as radiation or pollutant exposure. Understanding these dynamics is crucial for biosecurity in soil transport, bioremediation strategies at contaminated sites and accurate modelling of the global carbon budget.

Research from Nature Portfolio

A study employing repeated gamma irradiation on soil microcosms demonstrated that high‐dose exposure leads to a marked decline in bacterial diversity while enriching fungal and algal lineages freed from competitive suppression. Despite the reduction in living cells, functional gene diversity increased across major taxonomic groups, suggesting that cycles of population collapse and regrowth enable a broader range of metabolic strategies to persist. Distinct microbial clades exhibiting elevated tolerance to ionising stress were identified, indicating their potential roles in ecosystem recovery and biotechnological applications. This work highlights how sterilisation by radiation not only removes viable organisms but also reshapes the functional potential of soil communities through selective pressures on survivors and recolonisers.

Microbial Community Dynamics in Sterilized Soils publication trend

The graph below shows the total number of articles in microbial community dynamics in sterilized soils across all publications each year (not limited to Nature Index journals).

Technical terms

Sterilisation: The process of eliminating or inactivating all living microorganisms in soil, typically via heat, radiation or chemical treatment.

Gamma irradiation: The application of high‐energy photons to soil, used to eradicate living cells while preserving mineral and organic constituents.

Extracellular oxidative metabolism: Abiotic or enzyme‐mediated oxidation of organic substrates in the absence of living cells, contributing to soil CO₂ emissions.

Functional gene diversity: The variety of genetic sequences encoding metabolic functions within a microbial community, reflecting its potential to perform ecosystem processes.

References

1. Soil carbon dioxide emissions controlled by an extracellular oxidative metabolism identifiable by its isotope signature. Biogeosciences (2016).
2. An unknown oxidative metabolism substantially contributes to soil CO2 emissions. Biogeosciences (2013).
3. Robustness of the autochthonous microbial soil community after amendment of cattle manure or its digestate. Biology and Fertility of Soils (2019).
4. Changes in soil taxonomic and functional diversity resulting from gamma irradiation. Scientific Reports (2019).
5. Impact of sterilization methods on dissolved trace metals concentrations in complex natural samples: Optimization of UV irradiation. MethodsX (2019).