Stability of the permafrost peatlands carbon pool under climate change and wildfires during the last 150 years in the northern Great Khingan Mountains, China

Cong, Jinxin; Gao, Chuanyu; Han, Dongxue; Li, Yunhui; Wang, Guoping

doi:10.1016/j.scitotenv.2019.136476

Cited by 30 publications

(10 citation statements)

References 49 publications

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“…According to statistics, the annual CH 4 emission from peatland accounts for 4-10% of the total global CH 4 emission (Mikaloff Fletcher et al, 2004). Climate warming has significantly affected the carbon stability of peatlands in permafrost regions (Cong et al, 2020). Therefore, it is necessary to clarify the biochemical process of this unique ecosystem.…”

Section: Introductionmentioning

confidence: 99%

Soil Enzyme Activities and Their Relationships With Soil C, N, and P in Peatlands From Different Types of Permafrost Regions, Northeast China

Liu

Song

Dong

et al. 2021

Front. Environ. Sci.

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Peatland is a key component of terrestrial ecosystems in permafrost regions and have important effects on climate warming. Soil enzymes are involved in biogeochemical cycle of soil carbon (C), nitrogen (N) and phosphorus (P), which can be used as early sensitive indicators of soil nutrient changes caused by climate change. To predict the possible effects of permafrost degradation on soil enzymes in peatlands, ten peatlands from three types of permafrost regions along the permafrost degradation sequence (predominantly continuous permafrost region-predominantly continuous and island permafrost region-sparsely island permafrost region) in northeast China were selected to examine the activities of soil invertase, β-glucosidase, urease and acid phosphatase and their relationships with soil physicochemical properties. The results demonstrated that permafrost type had significant effect on soil enzyme activities. Soil enzyme activities in predominantly continuous and island permafrost region were significantly higher than those in sparsely island permafrost region and predominantly continuous permafrost region. The activities of four soil enzymes were higher in 0–15 cm than 15–30 cm soil layer. Soil enzymes activities were positively correlated with soil ammonia nitrogen (NH4+-N), soil moisture content (SMC), total phosphorus (TP) and total nitrogen (TN), but negatively correlated with soil nitrate nitrogen (NO3−-N). Soil inorganic nitrogen and moisture contents were the main factors affecting soil enzyme activities, with NH4+-N accounted for 41.6% of the variance, SMC 29.6%, and NO3−-N 11.0%. These results suggested that permafrost degradation may change soil enzyme activities by changing soil physicochemical properties. In this study, only 0–30 cm peat soil in permafrost regions was collected during the complete thawing period of permafrost active layer, further studies should be placed on the change of soil enzyme activities in active layer and permafrost layer during freezing and thawing process in the southernmost location of northeast China in the Eurasia permafrost body and boreal forest belt.

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Section: Introductionmentioning

confidence: 99%

Soil Enzyme Activities and Their Relationships With Soil C, N, and P in Peatlands From Different Types of Permafrost Regions, Northeast China

Liu

Song

Dong

et al. 2021

Front. Environ. Sci.

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“…This trend has implications for the preservation of stored carbon in peatlands facing increased drought frequency and duration associated with climate change predictions (Karl, Melillo, Peterson, & Hassol, 2009) and the resulting increase in the frequency of fire (Turetsky et al, 2014; Walker et al, 2019). In some ecosystems, low‐severity fire has been shown to create a pool of slower‐cycling carbon (Figure 6; Figure S7) that can mitigate future carbon losses (Cong et al, 2020; Efremova & Efremov, 2006; Leifeld et al, 2012, 2018; Ludwig et al, 2018). Moreover, alteration of microbial communities can reduce heterotrophic respiration, potentially resulting in a negative feedback mechanism to climate change (Holden et al, 2013, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…Often, a regime of low to intermediate fire frequency and intensity increases carbon storage in the soils of many ecosystem types (Cong, Gao, Han, Li, & Wang, 2020;Pingree, Homann, Morrissette, & Darbyshire, 2012;Richards, Cook, & Lynch, 2011;Wirth et al, 2002). This trend has implications for the preservation of stored carbon in peatlands facing increased drought frequency and duration associated with climate change predictions (Karl, Melillo, Peterson, & Hassol, 2009) and the resulting increase in the frequency of fire (Turetsky et al, 2014;Walker et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Low‐severity fire as a mechanism of organic matter protection in global peatlands: Thermal alteration slows decomposition

Flanagan

Wang

Winton

et al. 2020

Global Change Biology

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Worldwide, regularly recurring wildfires shape many peatland ecosystems to the extent that fire‐adapted species often dominate plant communities, suggesting that wildfire is an integral part of peatland ecology rather than an anomaly. The most destructive blazes are smoldering fires that are usually initiated in periods of drought and can combust entire peatland carbon stores. However, peatland wildfires more typically occur as low‐severity surface burns that arise in the dormant season when vegetation is desiccated, and soil moisture is high. In such low‐severity fires, surface layers experience flash heating, but there is little loss of underlying peat to combustion. This study examines the potential importance of such processes in several peatlands that span a gradient from hemiboreal to tropical ecozones and experience a wide range of fire return intervals. We show that low‐severity fires can increase the pool of stable soil carbon by thermally altering the chemistry of soil organic matter (SOM), thereby reducing rates of microbial respiration. Using X‐ray photoelectron spectroscopy and Fourier transform infrared, we demonstrate that low‐severity fires significantly increase the degree of carbon condensation and aromatization of SOM functional groups, particularly on the surface of peat aggregates. Laboratory incubations show lower CO2 emissions from peat subjected to low‐severity fire and predict lower cumulative CO2 emissions from burned peat after 1–3 years. Also, low‐severity fires reduce the temperature sensitivity (Q10) of peat, indicating that these fires can inhibit microbial access to SOM. The increased stability of thermally altered SOM may allow a greater proportion of organic matter to survive vertical migration into saturated and anaerobic zones of peatlands where environmental conditions physiochemically protect carbon stores from decomposition for thousands of years. Thus, across latitudes, low‐severity fire is an overlooked factor influencing carbon cycling in peatlands, which is relevant to global carbon budgets as climate change alters fire regimes worldwide.

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“…The Greater Khingan forest is located above the permafrost of Northeast China [41,42], where the warming-associated acceleration of snow melting and surface-thawing water tends to be maintained in shallow soil [43]. The mean April snow cover remained at a high level of 45.1% during 1968-2018 (Figure 1b), and the snowmelt date changed little (Figure 3); both phenomena prevented the fire from advancing into early spring.…”

Section: Fire Season Expansionmentioning

confidence: 99%

Asymmetrical Lightning Fire Season Expansion in the Boreal Forest of Northeast China

Gao

Wang

et al. 2021

Forests

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All-season warming is assumed to advance snowmelt and delay snow accumulation; additionally, coupled with warming-induced drought stress, all-season warming could extend both the beginning and the end of the fire season. Using fire data updated for 1968–2018, we found an asymmetrical expansion of the lightning fire season in the boreal forest of Northeast China. Lightning fires have not advanced into the early fire season (May–June) but have largely extended into the snowless late fire season (July–September) since the late 1990s (mean end Julian date delayed by 51.1 days for 1998–2018 compared with 1968–1997, p < 0.001). Despite significant warming, the Julian days of snowmelt have changed only slightly, which has prohibited the fire season from advancing into early spring. The expansion of lightning fires into July–September was associated with a warming-induced significant increase in evapotranspiration and a decrease in soil/fuel moisture.

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Stability of the permafrost peatlands carbon pool under climate change and wildfires during the last 150 years in the northern Great Khingan Mountains, China

Cited by 30 publications

References 49 publications

Soil Enzyme Activities and Their Relationships With Soil C, N, and P in Peatlands From Different Types of Permafrost Regions, Northeast China

Soil Enzyme Activities and Their Relationships With Soil C, N, and P in Peatlands From Different Types of Permafrost Regions, Northeast China

Low‐severity fire as a mechanism of organic matter protection in global peatlands: Thermal alteration slows decomposition

Asymmetrical Lightning Fire Season Expansion in the Boreal Forest of Northeast China

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