Abstract: Although northern peatlands are significant sources of atmospheric methane (CH₄) and carbon dioxide (CO₂), the spatial patterns of these emissions in the context of climate change remain poorly understood. In this study, peat cores were collected from different altitudes and microtopographies in peatlands of Changbai Mountain. Through an anaerobic incubation experiment, we combined gas monitoring with peat physicochemical properties to investigate how depth, microtopography, and altitude influenced the emission potentials of CH₄ and CO₂. The results showed that both CH₄ and CO₂ emissions decreased toward deeper peat. CH₄ and CO₂ emissions from the surface peat (0-5 cm) were 8.13±4.14 mg·g^-1 and 28.7±13.3 mg·g^-1 dry peat, respectively. CH₄ emissions from surface peat were 1.8-5.6 times higher than in subsurface peat (5-20 cm) and 1.6-9.6 times higher than in deep peat (20-40 cm). Similarly, CO₂ emissions of surface peat were 1.5-3.8 times higher than that in subsurface peat and 1.2-4.9 times higher than that in deep peat. Meanwhile, both elevation and microtopography had significant effects (P<0.05) on CH₄ and CO₂ emissions from surface peat. High-elevation peatlands and hummocks had higher CH₄ and CO₂ emission potentials. The cumulative CH₄ and CO₂ emissions were significantly positively correlated with soil pH and water-extractable organic carbon (WEOC) content (pH: R²=0.43-0.52, P<0.05; WEOC: R²=0.64-0.72, P<0.05), and were significantly negatively correlated with the specific ultraviolet absorbance (SUVA₂₅₄) of soluble organic matter and the ratio of carbon-to-nitrogen content of organic matter (SUVA₂₅₄: R²=0.44-0.47, P<0.05; C/N: R²=0.74-0.79, P<0.05). Our results indicate that the spatial variability of carbon emission potential in peatlands is influenced by pH and the availability of organic carbon. These findings identify the key factors driving carbon emissions of peatlands and improve our understanding of carbon loss potential across different spatial scales, particularly in the context of climate change.

Key words: microtopography, elevation, depth, organic matter, CH₄, CO₂