Fire frequency and type regulate the response of soil carbon cycling and storage to fire across soil depths and ecosystems: A meta-analysis

Xu, Shan; Eisenhauer, Nico; Pellegrini, Adam F. A.; Wang, Junjian; Certini, Giacomo; Guerra, Carlos A.; Lai, Derrick Y.F.

doi:10.1016/j.scitotenv.2022.153921

Cited by 21 publications

(12 citation statements)

References 83 publications

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“…These findings suggest that if detritus is heated <325 °C and soil heated <375 °C during a low- or moderate-intensity wildfire in a similar environment, there is a potential for a net increase in the production of DOC, even though TOC levels are expected to decrease. A meta analysis of hundreds of wildfire cases has found that wildfires either increase or decrease the soil DOC content and thus do not statistically significantly alter soil DOC content, different from the significant decrease in the soil organic carbon content . Our results provide laboratory-based evidence that these inconclusive observations are likely caused by the diverse and mixed thermal behaviors of various DOM compounds across a different range of soil heating temperatures during various wildfire events.…”

Section: Resultsmentioning

confidence: 57%

“…A meta analysis of hundreds of wildfire cases has found that wildfires either increase or decrease the soil DOC content and thus do not statistically significantly alter soil DOC content, different from the significant decrease in the soil organic carbon content. 14 Our results provide laboratory-based evidence that these inconclusive observations are likely caused by the diverse and mixed thermal behaviors of various DOM compounds across a different range of soil heating temperatures during various wildfire events.…”

Section: Resultsmentioning

confidence: 77%

“…12 In contrast, the quantity of DOM formed during heating, indicated by dissolved organic carbon (DOC) content, usually first increases and then decreases with increasing heating temperature. 13,14 Although studies have reported high losses in DOC content in materials heated at ≥500 °C, 13−15 recent studies found that the DOC content was often higher in materials heated at ≤250 °C than in the nonheated reference. 10,13,16 Thus, there should be two heating temperature thresholds.…”

Section: Introductionmentioning

confidence: 99%

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Temperature Thresholds of Pyrogenic Dissolved Organic Matter in Heating Experiments Simulating Forest Fires

Zhang,

Wang,

Guan

et al. 2023

Environ. Sci. Technol.

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Heating temperature (HT) during forest fires is a critical factor in regulating the quantity and quality of pyrogenic dissolved organic matter (DOM). However, the temperature thresholds at which maximum amounts of DOM are produced (TTmax) and at which the DOC gain turns into net DOC loss (TT0) remain unidentified on a component-specific basis. Here, based on solid-state 13C nuclear magnetic resonance, absorbance and fluorescence spectroscopies, and Fourier transform ion cyclotron resonance mass spectrometry, we analyzed variations in DOM composition in detritus and soil with HT (150–500 °C) and identified temperature thresholds for components on structural, fluorophoric, and molecular formula levels. TTmax was similar for detritus and soil and ranged between 225 and 250 °C for bulk dissolved organic carbon (DOC) and most DOM components. TT0 was consistently lower in detritus than in soil. Moreover, temperature thresholds differed across the DOM components. As the HT increased, net loss was observed initially in molecular formulas tentatively associated with carbohydrates and aliphatics, then proteins, peptides, and polyphenolics, and ultimately condensed aromatics. Notably, at temperatures lower than TT0, particularly at TTmax, burning increased the DOC quantity and thus might increase labile substrates to fuel soil microbial community. These composition-specific variations of DOM with temperature imply nonlinear and multiple temperature-dependent wildfire impacts on soil organic matter properties.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temperature Thresholds of Pyrogenic Dissolved Organic Matter in Heating Experiments Simulating Forest Fires

Zhang,

Wang,

Guan

et al. 2023

Environ. Sci. Technol.

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“…Interestingly, our analysis revealed that postfire declines in R h were associated with increases in pH (Figure 5). This can be explained by an increased ratio of fungal to bacterial biomass and microbial C use efficiency as pH increases, which were linked to the reduced microbial turnover rate and respiration allocation (Blagodatskaya & Anderson, 1998; Jones et al, 2019; Xu et al, 2022). Increases in bulk density following fires are typically caused by the collapse of soil aggregates and pore‐clogging with ash or free clay minerals (Alcañiz et al, 2018; Hu et al, 2021), which lead to a decrease in water holding capacity and oxygen diffusion adversely affecting R h .…”

Section: Discussionmentioning

confidence: 99%

Section: Soil Biogeochemistry Regulates the Responses Of Soil Respira...mentioning

confidence: 99%

Fire decreases soil respiration and its components in terrestrial ecosystems

Zhou,

Liu,

et al. 2023

Functional Ecology

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The impact of fire on above‐ground biomass has significant consequences on soil carbon (C) dynamics, which is essential in predicting the global C budget during the Anthropocene. However, there is considerable spatiotemporal variability in the directions and magnitudes of fire effects on soil respiration, and the drivers associated with these effects are not well understood. Here, we conducted a global meta‐analysis of 1327 individual observations from 170 studies to determine the extent to which fire influenced soil total respiration (Rs), heterotrophic respiration (Rh) and autotrophic respiration (Ra). We found fires reduced Rs, Rh and Ra, with an average effect of −11.0%, −17.5% and −40.6%, compared with unburnt sites. Specifically, wildfires significantly reduced Rs and Rh (−20.4% and −25.0%, respectively), and prescribed fire significantly decreased Ra (−74.8%). The influences of fire on Rs and its components were moderated by fire severity, season, type, climate zones and biomes. After several years from the time of the fire, the negative effects of fire on Rs diminished and then recovered to a state not significantly different from unburnt sites; Rh exhibited a similar but decayed temporal response. Similarly, the negative effects on Ra disappeared after 3 years following the latest fire. The magnitude of the effect on Rs was strongly associated with soil temperature, cation exchange capacity, total nitrogen (N) content and N‐acquiring enzyme activity. In contrast, the magnitude of the effect on Rh significantly changed with pH, bulk density, texture, soil C and nutrient contents, and C‐acquiring enzyme activity. Our findings advance the understanding of the inhibition and associated mechanisms of fire on Rs and its components, highlighting the need for new research efforts to predict the spatial‐temporal shifts in underground C‐cycling induced by fire. Read the free Plain Language Summary for this article on the Journal blog.

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