Work

Precipitation-dependent nonlinear accumulation of soil organic carbon in response to warming via microbial residues

Year: 2026

Type: article

Abstract: Climate change reshapes global terrestrial ecosystems via rising temperatures and shifting precipitation, jointly regulating soil organic carbon (SOC) dynamics. Multi-factorial experiments are vital for unraveling climatic interactions, yet most only apply one warming level, leaving ecosystem nonlinear responses poorly explored. Based on a five-year field experiment in an alpine meadow, we examined the interactive effects of multi-level warming (+0, +1, +2 and +4 °C) and increased precipitation (+50%) on SOC and its nonlinear responses to warming. We found that +4 °C warming combined with increased precipitation led to a 55% increase in SOC in the topsoil (0–10 cm), whereas warming alone had negligible effects. This SOC increase is primarily attributed to the accumulation of mineral-associated organic carbon linked to fungal residues. Lower warming levels (+1 °C and +2 °C) had little impact on mineral-associated organic carbon, fungal residues, and bacterial biomass, whereas these variables increased markedly at +4 °C only under increased precipitation. This consistent gradient trend revealed a precipitation-dependent nonlinear response of the three belowground variables to warming, with identified functional thresholds falling within the 2–4 °C range. These findings highlight the need to account for interactive climate drivers and potential nonlinear ecosystem responses to refine carbon–climate feedback projections.

Source: Communications Earth & Environment

DOI: 10.1038/s43247-026-03941-x