With global warming, the large amount of greenhouse gas emissions released by permafrost degradation is important in the global carbon and nitrogen cycle. To study the feedback effect of greenhouse gases on climate change in permafrost regions, emissions of CO₂, CH₄, and N₂O were continuously measured by using the static chamber-gas chromatograph method, in three forest soil ecosystems (Larix gmelinii, Pinus sylvestris var. mongolica, and Betula platyphylla) of the Daxing’an Mountains, northeast China, from May 2016 to April 2018. Their dynamic characteristics, as well as the key environmental affecting factors, were also analyzed. The results showed that the flux variation ranges of CO₂, CH₄, and N₂O were 7.92 ± 1.30~650.93 ± 28.12 mg·m⁻²·h⁻¹, −57.71 ± 4.65~32.51 ± 13.03 ug·m⁻²·h⁻¹, and −3.87 ± 1.35~31.1 ± 2.92 ug·m⁻²·h⁻¹, respectively. The three greenhouse gas fluxes showed significant seasonal variations, and differences in soil CO₂ and CH₄ fluxes between different forest types were significant. The calculation fluxes indicated that the permafrost soil of the Daxing’an Mountains may be a potential source of CO₂ and N₂O, and a sink of CH₄. Each greenhouse gas was controlled using different key environmental factors. Based on the analysis of Q₁₀ values and global warming potential, the obtained results demonstrated that greenhouse gas emissions from forest soil ecosystems in the permafrost region of the Daxing’an Mountains, northeast China, promote the global greenhouse effect.

In recent years, geological disasters have frequently occurred on basarlt highway slopes. Studying the stability of highway slopes in this type of area is of great significance for traffic safety. However, due to the high cost and low efficiency of traditional monitoring and experimental methods for slope engineering, these methods are not conducive to the quick and comprehensive identification of regional slope stability. Due to the high iron content of basalt, iron staining anomalies in the ore prospecting field are reinterpreted from an engineering perspective in this study. Taking the S3K section of a highway in Changbai County, China, as an example, Landsat8 remote sensing (RS) images from 2014, 2016, 2018, 2020, and 2021 are selected, and principal component analysis is used to extract iron staining anomalies in the region. Combined with field investigation and evidence collection, the corresponding rock mass fragmentation is distinguished via iron staining anomalies. Then, according to previous research results, eight indexes including annual rainfall, slope, topographic relief, surface roughness, vegetation index, leaf area index (LAI), root depth of vegetation, and human activity intensity are selected for investigation. The artificial neural network–cellular automata (ANN-CA) model is established, and the rock fragmentation classification data obtained based on iron staining anomalies are used to simulate the area. Next, the calculation formula of slope stability is determined based on the simulation results, and the stability of a high and steep slope in the area is calculated and analyzed. Finally, a comparison with an actual field investigation shows that the effect of the proposed method is good. The research findings reveal that it is feasible to judge the stability of a high and steep slope in a basalt area via the use of iron staining anomalies as an indicator. The findings are tantamount to expanding the application scope of RS in practical engineering.

Permafrost zones are currently experiencing rapid warming, and dissolved organic matter (DOM) is a potentially important pathway for carbon release from permafrost after thawing. In this study, based on the UV–Vis spectral data and parallel factor analysis of fluorescence excitation‐emission matrix (EEM) spectrophotometry, we investigated the source and composition of DOM at different thawing stages in the permafrost zone of Northeast China. The results indicate that there are significant differences in the content of soil dissolved organic carbon (DOC) among different types of permafrost zones (continuous permafrost: 143–347 mg/kg, discontinuous permafrost 172–462 mg/kg, isolated patches permafrost 195–610 mg/kg), and the permafrost types had a significant effect on soil DOC ( p < 0.05). Five fluorescent components were identified from all samples, including four humic acid‐like substances (C1, C2, C3, C4) and one tryptophan‐like substance (C5). The proportion of C5 in the deep layer of the sporadic patch permafrost area (55.39%) is about 49% higher than that in the continuous permafrost area (37.25%). With increasing soil depth, the characteristics of DOM transition from high DOC value, high aromaticity, high molecular weight, and plant origin to low DOC value, low aromaticity, low molecular weight, and microbial origin. The results of soil DOM component analysis indicate that the content of C5 significantly increases ( p < 0.01) in the deeper layers of isolated patch permafrost. With the change of permafrost types, the risk of DOM decomposition may increase. These findings contribute to a deeper understanding of the dynamics and stability of DOM in permafrost under environmental warming, as well as its biogeochemical impacts in natural environments.

Global warming profoundly alters the stability of soil organic matter (SOM) in permafrost zones, yet the underlying mechanisms governing SOM stability in permafrost landscapes at different stages of degradation remain unclear. This study utilised soil samples from the 0–50 cm layer collected from both continuous and isolated patches permafrost zones in the Daxing’an Mountains for laboratory incubation experiments at constant temperatures of 5 and 15 °C. The results for SOC, Fe and Al oxide content, δ ¹³C and MBC indicate that SOM in isolated patchy permafrost possesses greater bioavailability and higher decomposability under warming, and carbon mineralization in shallow soils is more temperature-sensitive (Q₁₀ = 4.24). After 89 days of incubation, the mineralisation rate in mineral-rich deep soil was only half that of organic-rich surface soil. Furthermore, as the ratio of Fe/Al oxides to organic carbon increased, the sensitivity of SOM decomposition to temperature decreased significantly. Overall, the stability of organic matter in permafrost is jointly regulated by the intrinsic molecular properties of the organic matter and the protective effect of minerals; furthermore, this protective effect can significantly delay the process by which peatlands in permafrost regions transition from carbon sinks to carbon sources.

Permafrost is an important carbon pool for terrestrial ecosystems and a significant source of atmospheric greenhouse gases, but the effects of ground vegetation and snow cover on permafrost greenhouse gas fluxes are still unclear. The soil–atmosphere exchange fluxes of greenhouse gases (mainly carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)) occupy key roles during the winter snow and the vegetation growing seasons. Here, a typical Larix gmelinii forest, located in the permafrost region of the Daxing’an Mountains, northeast China, was studied. Using the static chamber-gas chromatograph method, the relationship between soil greenhouse gas emissions, ground vegetation, and snow cover was investigated. We found that the CO₂, CH₄, and N₂O cumulative fluxes from vegetative soils had increased by 19.5%, 37.5%, and 10.7%, compared with fluxes from areas where the ground vegetation had been removed. Snow cover increased soil CO₂ cumulative flux by 53.1% and soil N₂O cumulative flux by 28.6%, and soil CH₄ cumulative flux decreased by 39.3%. Our results show that snow cover and ground vegetation removal reduce CO₂ and N₂O emissions from permafrost soils. Ground vegetation removal also increases the absorption of CH₄ in permafrost soils, while snow cover removal promotes CH₄ emissions. These findings confirm the effects of ground vegetation and snow cover on the transformation processes of greenhouse gases from forest ecosystems in permafrost regions. Therefore, this research provides scientific data support for the improvement of land surface climate models and the mitigation of climate change in cold regions.