Soil Heating at High Temperatures and Different Water Content: Effects on the Soil Microorganisms

Abstract

Soil properties determining the thermal transmissivity, the heat duration and temperatures reached during soil heating are key factors driving the fire-induced changes in soil microbial communities. The aim of the present study is to analyze, under laboratory conditions, the impact of the thermal shock (infrared lamps reaching temperatures of 100 °C, 200 °C and 400 °C) and moisture level (0%, 25% and 50% per soil volume) on the microbial properties of three soil mixtures from different sites. The results demonstrated that the initial water content was a determinant factor in the response of the microbial communities to soil heating treatments. Measures of fire impact included intensity and severity (temperature, duration), using the degree-hours method. Heating temperatures produced varying thermal shock and impacts on biomass, bacterial activity and microbial community structure.

Microbial Community Interactions Are Sensitive to Small Changes in Temperature

“…Temperature sensitivity of interactions between microbes has also been discovered in many different natural communities. In soil, short-term extreme heat shock (>100 • C) has been shown to cause a long-term reduced growth of the treated microbial communities persisting for multiple generations (Barreiro et al, 2020). More moderate long-term alterations of growth temperature in Alpine soils have shown that these soil communities have a growth optimum between 27 and 30 • C and that the community structure was substantially altered, in accordance with the findings in this study.…”

Thermostable Keystone Bacteria Maintain the Functional Diversity of the Ixodes scapularis Microbiome Under Heat Stress

“…Network parameters thus suggest that heat stress reduces the robustness and stability of tick microbial communities. Shifts on microbial interaction patterns as result of temperature variation has been previously described in soil bacterial communities [3,8,13,20,54].…”

Effects of fire on CO2, CH4, and N2O exchange in a well‐drained Arctic heath ecosystem

“…Because soil chemistry is influenced by many factors, such as organic matter input and environmental factors, our results are only a snapshot of the soil conditions at the time of sampling. When it comes to microbial‐driven soil processes, temperatures reached during the experimental fire at the surface may have been high enough to inhibit microbial growth close to the surface (Bárcenas‐Moreno & Bååth, 2009; Barreiro et al, 2020). However, microbial growth recovers rapidly, in response to increased nutrients availability and C from dead organisms after fire (Bárcenas‐Moreno & Bååth, 2009; Barreiro et al, 2020).…”

“…When it comes to microbial‐driven soil processes, temperatures reached during the experimental fire at the surface may have been high enough to inhibit microbial growth close to the surface (Bárcenas‐Moreno & Bååth, 2009; Barreiro et al, 2020). However, microbial growth recovers rapidly, in response to increased nutrients availability and C from dead organisms after fire (Bárcenas‐Moreno & Bååth, 2009; Barreiro et al, 2020). The impacts of fire on microbial growth and biomass are determined by the residence time of high temperatures rather than the maximum temperature (Lombao et al, 2020).…”