Abstract
Wildfires act as important ecosystem controls and can benefit fire-adapted biomes by promoting habitat heterogeneity, seed germination and disease control. However, the frequency of high-severity fires and the extent of total burn area have increased since the 1970s, transforming both the organic and inorganic composition of soil. In this Review, we outline the molecular-scale transformations and biogeochemical interactions of soil organic matter (SOM) and metals induced by wildfires and explore their impacts on post-fire human health and ecosystem recovery. Wildfires enhance organic matter solubility and increase the number of nitrogen-containing SOM molecules by up to 32%. Additionally, wildfires can double the concentration of toxic polycyclic aromatic hydrocarbons (PAHs) in soil and induce the formation of toxic metal species such as As(III) and Cr(VI) through redox reactions. In post-fire environments, pyrogenic organic matter is susceptible to microbial degradation and can interact with soil minerals to influence metal redox cycling. Moreover, post-fire products such as karrikins and PAHs promote and inhibit revegetation, respectively, influencing ecosystem recovery. Improved techniques to monitor changes in the soil and the surrounding ecosystem are needed to better understand and mitigate the negative effects of wildfires.
| Original language | English |
|---|---|
| Pages (from-to) | 431-446 |
| Number of pages | 16 |
| Journal | Nature Reviews Earth and Environment |
| Volume | 5 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2024 |
| Externally published | Yes |
Funding
The authors acknowledge support from the Center for Innovation in Global Health at Stanford University and the London School of Hygiene and Tropical Medicine under the Planetary Health Postdoctoral Fellowship (A.M.L.), Stanford Doerr School of Sustainability under the Stanford Earth Postdoctoral Fellowship (C.C.E.A.), Stanford Woods Institute for the Environment (S.F.), the National Science Foundation under grant no. 2114868 (H.K.R., J.P.VR., T.B.) and US Department of Agriculture National Institute of Food and Agriculture through AFRI grant no. 2021-67019-34608 (H.K.R., J.P.VR, T.B.).