摘要
The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the interplay of climate,soil and vegetation type.Here,we synthesized currently available soil carbon data to show that mean organic carbon density in the topsoil(0-10 cm)in TP grassland(3.12±0.52 kg C m^(-2))is less than half of that in Arctic tundra(6.70±1.94 kg C m^(-2)).Such difference is primarily attributed to their difference in radiocarbon-inferred soil carbon turnover times(547 years for TP grassland versus 1609 years for Arctic tundra)rather than to their marginal difference in topsoil carbon inputs.Our findings highlight the importance of improving regional-specific soil carbon turnover and its controlling mechanisms across permafrost affected zones in ecosystem models to fully represent carbon-climate feedback.
素有"世界屋脊"之称的青藏高原是除了北极苔原之外最大的冻土分布带,且该区域存储着大量的土壤有机碳.然而,这两大冻土分布带的土壤有机碳密度却存在着很大的差别.表层土壤扮演着连接地表植被和下层冻土的桥梁作用,但是我们对于两者表层土壤有机碳密度的差别及其驱动机制的理解却十分匮乏.本研究基于多源观测数据发现青藏高原草地表层土壤有机碳密度仅为北极苔原的一半,然而两者的潜在碳输入之间却没有明显差异.基于^(14)C数据的进一步分析表明北极苔原表层土壤碳周转时间(1609年)约为青藏高原草地(547年)的3倍,这一结果意味着碳周转时间驱动了这两个区域土壤有机碳密度的差异.该研究强调了碳周转时间对于理解不同冻土分布带土壤碳差异的重要性,也指示了未来的生态系统模型应该进一步提升对土壤碳周转过程的模拟能力.
作者
Donghai Wu
Dan Liu
Tao Wang
Jinzhi Ding
Yujie He
Philippe Ciais
Gengxin Zhang
Shilong Piao
武东海;刘丹;汪涛;丁金枝;贺钰杰;Philippe Ciais;张更新;朴世龙(Sino-French Institute for Earth System Science,College of Urban and Environmental Sciences,Peking University,Beijing 100871,China;Key Laboratory of Alpine Ecology,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100085,China;Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100085,China;Department of Earth System Science,University of California,Irvine,CA 92697,USA;Laboratoire des Sciences du Climat et de l’Environnement,LSCE/IPSL,CEA-CNRS-UVSQ,UniversitéParis-Saclay,F-91191 Gif-sur-Yvette,France)
基金
This work was supported by Preliminary Research on Three Poles Environment and Climate Change(2019YFC1509103)
the National Natural Science Foundation of China(41861134036 and 41922004)
the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)
the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA19070303 and XDA20050101).
