摘要
挪威南部的小型源头集水区Storgama径流中硝酸盐(NO_3)和总有机碳(TOC)浓度和通量20年记录的波动起伏与气候和酸沉降有关。NO_3的长期下降与NO_3沉降减少和冬季水流量增加有关,而TOC的长期增加与硫沉降减少有关。我们用描述这些记录长期趋势和季节性变化的多元回归模型,来预测在气候变化和酸沉降的情景条件下的未来浓度。所有的情景都表明,NO_3通量降低,TOC通量增加;2071～2100年间预测的最大变化分别是-86%和+24%。不确定性是:对未来温度的预测明显高于历史记录。生态系统过程(氮的矿化)对温度、土壤的氮富集、环境条件逐步变化的非线性反应也会影响碳和氮的未来淋溶。
Fluctuations in the 20-year record of nitrate (NO_3) and total organic carbon (TOC) concentrations and fluxes in runoff at the small headwater catchment Storgama,southern Norway,were related to climate and acid deposition.The long-term decline in NO_3 related to reduced NO_3 deposition and increased winter discharge,whereas the long-term increase in TOC related to reduced sulfur deposition.Multiple regression models describing long-term trends and seasonal variability in these records were used to project future concentrations given scenarios of climate change and acid deposition.All scenarios indicated reduced NO_3 fluxes and increased TOC fluxes;the largest projected changes for the period 2071 -2100 were -86% and 24%,respectively.Uncertainties are that the predicted future temperatures are considerably higher than the historical record. Also,nonlinear responses of ecosystem processes (nitrogen [N] mineralization) to temperature,N-enrichment of soils,and step-changes in environmental conditions may affect future leaching of carbon and N.
