Thermal sensitivity and rising greenhouse gas emissions in riparian zone soils: Implications for ecosystem carbon dynamics

Abstract

Riparian zones, critical interfaces between aquatic and terrestrial ecosystems, play a significant role in global carbon dynamics and greenhouse gas (GHG) emissions. This study investigates the thermal sensitivity (Q₁₀) of soil organic carbon decomposition and its implications for GHG emissions in the riparian soils of the Three Gorges Reservoir, China. Through a 42-day incubation experiment at four temperatures (15 °C, 22 °C, 29 °C, and 36 °C), we quantified the Q₁₀ values for methane (CH₄) and carbon dioxide (CO₂) emissions, revealing spatial heterogeneity and a positive correlation with temperature. The Q₁₀ for CH₄ (2.5) was significantly higher than for CO₂ (1.4), indicating a stronger temperature sensitivity of CH₄ emissions. Structural equation modeling identified soil pH and mean annual temperature as key drivers of Q₁₀ variations. Projections based on Shared Socioeconomic Pathways from the IPCC-AR6 suggest that by 2100, CH₄, CO₂, and CO₂-equivalent emissions from riparian zones could increase by 4.9–44.3 %, 4.3–17.4 %, and 4.0–20.0 %, respectively. These findings underscore the importance of riparian zones in climate feedback loops and highlight the need for targeted management strategies to mitigate GHG emissions in these vulnerable ecosystems.