Bidirectional Gradient Effect of CO2 Concentration in Soil Profile of Karst Peak–cluster Depressions and Its Influencing Factors
Year: 2025
Type: article
Abstract: Soil CO2 in karst regions is a crucial driver of karst processes. Investigating the stratification effects of soil profile CO2 concentration and its response to environmental factors could provide essential insights into karst carbon sinks and carbon cycling. This study examines five land use types (shrubland, forest, orchard, grassland, and farmland) in a typical peak-cluster depression in Guancun, Guangxi. Soil CO2 concentrations at different depths, environmental factors, and standard dissolution test pieces were analyzed using correlation and principal component analysis. The results show that soil CO2 concentrations exhibit seasonal variations, being higher in the rainy season and lower in the dry season. Soil temperature correlated positively with soil CO2 concentration overall (R2 = 0.53, P < 0.05). Temperature is the key factor influencing soil CO2 at depths of 5 and 20 cm. At 50 cm depth, CO2 concentration is primarily affected by karst processes. A bidirectional gradient effect was observed in soil CO2 concentration, with lower levels at 5 and 50 cm and a peak at 20 cm depth, which is attributed to karst processes and serves as strong evidence of karst carbon sinks. However, whether soil CO2 concentration can directly indicate the intensity of subsurface karst processes and how it reflects carbon cycling in karst systems require further research.
Source: EARTH AND ENVIRONMENT
Authors: Yifei LIU, Qiong XIAO, Licheng SHEN, Yongli GUO, Fajia CHEN, Jiabin LI
Language: English
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDGs: Climate action, Life on land
Open Access status: hybrid
Funder: Southwest University
OpenAlex ID: W4410145404