The post-flooding carbon sequestration capacity of riparian areas

Fluvial-driven carbon capture systems are critical components of global carbon dynamics, yet their behavior in the aftermath of catastrophic industrial failures remains understudied. This study quantifies the carbon saturation deficit (CSD) and carbon sequestration potential (CSP) of riparian soils three years after flooding along the Paraopeba River, which was affected by the Brumadinho dam collapse in 2019. Topsoil samples (0–20 cm) were collected from three impacted riparian sites (A1, A2, and A3) and two undisturbed reference forests (R1 and R2). We integrated particle-size distribution and soil organic carbon (SOC) analyses to model the theoretical carbon saturation capacity. Our findings reveal that impacted riparian areas exhibit a significantly higher CSD (13.22 g kg^–1 to 15.91 g kg^–1) than reference sites (1.85 g kg^–1 to 4.58 g kg^–1), alongside elevated CSP values (averaging 22.96 to 23.58 % in riparian areas and 18.72 to 21.96 %). These results suggest that the post-flood recovery phase, driven by sediment deposition and subsequent vegetation re-establishment, creates a significant “carbon sink” opportunity. The high saturation deficit in impacted areas underscores their role as highly receptive substrates for SOC accumulation during ecological succession. This study provides a quantitative framework for SOM modeling in disaster-recovered landscapes, offering essential data for targeted restoration and long-term environmental monitoring in tropical riparian ecosystems.