Permanent land use and microbial contributions shape soil organic carbon stabilization in lake floodplains

作者：Toky Jeriniaina Rabearison, Jim Félix-Faure, François Guillemette, Michelle Garneau, Christine Martineau, Louis Astorg, Martin Chantigny, Virginie Favreau, J. Malko, Alexandre Roy, Vincent Maire · 发表于：Soil Biology and Biochemistry · 年份：2026 · DOI：10.1016/j.soilbio.2026.110199 · 被引用次数：1 · 研究领域：Soil Carbon and Nitrogen Dynamics、Microbial Community Ecology and Physiology、Biocrusts and Microbial Ecology

Floodplain ecosystems play a key role in soil organic carbon (SOC) storage, as they integrate inputs from both vegetation and deposited sediments. Promoting land uses with low anthropogenic disturbances helps maintain the function of these ecosystems as soil carbon (C) sinks. However, the tipping points along a disturbance gradient where land use transitions generate the largest SOC losses or gains remain unclear, though they are key for effective land use management and climate change mitigation. Because flood events can mobilize and enhance the loss of labile C, determining the main origin of stable SOC, whether from plants or soil microorganisms, is also important to identify the optimal combination of land use, vegetation, and soil type for SOC stabilization in floodplains. We examined how SOC stabilization and origin vary in the floodplain of Lake Saint-Pierre, Québec, Canada along an anthropogenic disturbance gradient of six land uses: conventional and improved croplands, temporary and permanent meadows, marshes, and forested swamps. In all 6 land uses at the same elevation, we quantified SOC stocks, mineral-associated organic matter - C (MAOM-C), soil δ 13 C and sugar biomarkers. Driven by land use change, variations in plant inputs were associated with changes in topsoil SOC storage. Forested swamps had the highest MAOM-C due to greater plant biomass inputs that increased both microbial- and plant-derived C. Across all land uses, microbial-derived sugars, particularly...