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Amino sugars, as the biomarkers of microbial residues, help explore soil microorganisms' response to global climate change. However, research on how microorganisms in the alpine meadows regulate the soil carbon cycle under the influence of climate change is limited. We hypothesized that climate change might cause different effects on soil microbial residues due to the impact on soil physical properties, chemical properties, and enzyme activities. Therefore, we conducted four-year continuous warming and increased precipitation experiments in the semi-arid grasslands to examine the differences in soil microbial residues at different depths under simulated changes. The results showed warming stimulated the accumulation of microbial residues, while increased precipitation led to their decline. The Glucosamine/Muramic Acid ratio trend indicates that the contribution of fungal residues was more significant than that of bacteria with increased precipitation, whereas that of bacterial residues exceeded that of fungi with warming. The increased precipitation had no significant effect on soil extracellular enzyme activities and amino sugar concentrations. In addition, changes in the different enzyme activities led to soil carbon loss and different amino sugar accumulation patterns under the warming treatment. These results may aid in assessing the responses of soil microorganisms to future climate change scenarios. [ABSTRACT FROM AUTHOR]

• A framework is proposed to assess the riverine carbon fluxes under climate change. • Sensitivity tests show that rainfall flow primarily influences carbon concentrations. • Seasonal variations in carbon concentrations are related to the thawing-freezing cycle. • Total carbon input is greater than output and rainfall contributes half of the carbon load. Riverine carbon dynamics connecting land and ocean carbon cycles play a crucial role in regulating global carbon turnover. Despite its importance, the impact of climate change and runoff components on riverine carbon dynamics, particularly in alpine regions, remains underexplored. In this study, we introduce a conceptual framework to assess the impact of climate change on riverine carbon fluxes across various runoff components. We use a distributed hydrological model and stable isotopes to identify key runoff components, then identify the dominant drivers of variability in runoff carbon concentrations. We establish component-specific relationships between carbon concentrations and dominant drivers, assessing the watershed carbon balance through a comparative analysis of carbon fluxes in various runoff components. The proposed framework was validated in a representative watershed on the Qinghai-Tibet Plateau, and it effectively captured the seasonal carbon dynamics and the impact of climate change and runoff components. Our results indicated that runoff and temperature dominate riverine carbon concentrations. The carbon fluxes associated with rainfall and groundwater showed higher sensitivity to runoff, while those in the snowmelt component were more sensitive to temperature. We found seasonal variability in carbon fluxes, with particulate organic carbon concentrations peaking at 4.80 mgC/L during the thawing period and other carbon components (i.e., dissolved organic carbon, dissolved inorganic carbon, particulate inorganic carbon) peaking during the freezing period. We quantified the total carbon input and output for the watershed as 15.12 tC/km2/yr and 12.19 tC/km2/yr, with 51.2% of the carbon influx attributed to rainfall, 10.9% to groundwater, and 37.9% to snowmelt. Our study enhances the understanding of riverine carbon dynamics and offers a promising approach for predicting carbon budgets under climate change. [ABSTRACT FROM AUTHOR]