Temperature sensitivity of soil respiration declines with climate warming in subalpine and alpine grassland soils

作者：Khatab Abdalla, Larissa Schierling, Yue Sun, Max A. Schuchardt, Anke Jentsch, Thomas Deola, Peter Wolff, Ralf Kiese, Eva Lehndorff, Johanna Pausch, Nele Meyer · 发表于：Biogeochemistry · 年份：2024 · DOI：10.1007/s10533-024-01179-3 · 被引用次数：12 · 研究领域：Climate change and permafrost、Soil and Unsaturated Flow、Soil Carbon and Nitrogen Dynamics

Abstract Warming as a climate change phenomenon affects soil organic matter dynamics, especially in high elevation ecosystems. However, our understanding of the controls of soil organic matter mineralization and dynamics remains limited, particularly in alpine (above treeline) and subalpine (below treeline) grassland ecosystems. Here, we investigated how downslope (warming) and upslope (cooling) translocations, in a 5-years reciprocal transplanting experiment, affects soil respiration and its temperature sensitivity (Q10), soil aggregation, and soil organic matter carbon (C) and nitrogen (N) composition (C/N ratio). Downslope translocation of the alpine (2440 m a.s.l.) and subalpine (1850 m a.s.l.) to the lowland site (350 m a.s.l.) resulted in a temperature change during the growing seasons of + 4.4K and + 3.3K, respectively. Warming of alpine soils (+ 4.4K) reduced soil organic carbon (SOC) content by 32%, which was accompanied by a significant decrease of soil macroaggregates. Macroaggregate breakdown induced an increased respiration quotient (qCO 2 ) by 27% following warming of alpine soils. The increase in qCO 2 respiration was associated with a significant decrease (from 2.84 ± 0.05 to 2.46 ± 0.05) in Q10, and a change in soil organic matter composition (lower C/N ratios). Cooling did not show the opposite patterns to warming, implying that other mechanisms, such as plant and microbial community shifts and adaptation, were involved. This study highlights the important r...